1 /*
2 * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 // no precompiled headers
26 #include "classfile/classLoader.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/icBuffer.hpp"
30 #include "code/vtableStubs.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "jvm_linux.h"
34 #include "memory/allocation.inline.hpp"
35 #include "memory/filemap.hpp"
36 #include "mutex_linux.inline.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "os_share_linux.hpp"
39 #include "prims/jniFastGetField.hpp"
40 #include "prims/jvm.h"
41 #include "prims/jvm_misc.hpp"
42 #include "runtime/arguments.hpp"
43 #include "runtime/extendedPC.hpp"
44 #include "runtime/globals.hpp"
45 #include "runtime/interfaceSupport.hpp"
46 #include "runtime/java.hpp"
47 #include "runtime/javaCalls.hpp"
48 #include "runtime/mutexLocker.hpp"
49 #include "runtime/objectMonitor.hpp"
50 #include "runtime/osThread.hpp"
51 #include "runtime/perfMemory.hpp"
52 #include "runtime/sharedRuntime.hpp"
53 #include "runtime/statSampler.hpp"
54 #include "runtime/stubRoutines.hpp"
55 #include "runtime/threadCritical.hpp"
56 #include "runtime/timer.hpp"
57 #include "services/attachListener.hpp"
58 #include "services/runtimeService.hpp"
59 #include "thread_linux.inline.hpp"
60 #include "utilities/decoder.hpp"
61 #include "utilities/defaultStream.hpp"
62 #include "utilities/events.hpp"
63 #include "utilities/growableArray.hpp"
64 #include "utilities/vmError.hpp"
65 #ifdef TARGET_ARCH_x86
66 # include "assembler_x86.inline.hpp"
67 # include "nativeInst_x86.hpp"
68 #endif
69 #ifdef TARGET_ARCH_sparc
70 # include "assembler_sparc.inline.hpp"
71 # include "nativeInst_sparc.hpp"
72 #endif
73 #ifdef TARGET_ARCH_zero
74 # include "assembler_zero.inline.hpp"
75 # include "nativeInst_zero.hpp"
76 #endif
77 #ifdef TARGET_ARCH_arm
78 # include "assembler_arm.inline.hpp"
79 # include "nativeInst_arm.hpp"
80 #endif
81 #ifdef TARGET_ARCH_ppc
82 # include "assembler_ppc.inline.hpp"
83 # include "nativeInst_ppc.hpp"
84 #endif
85 #ifdef COMPILER1
86 #include "c1/c1_Runtime1.hpp"
87 #endif
88 #ifdef COMPILER2
89 #include "opto/runtime.hpp"
90 #endif
91
92 // put OS-includes here
93 # include <sys/types.h>
94 # include <sys/mman.h>
95 # include <sys/stat.h>
96 # include <sys/select.h>
97 # include <pthread.h>
98 # include <signal.h>
99 # include <errno.h>
100 # include <dlfcn.h>
101 # include <stdio.h>
102 # include <unistd.h>
103 # include <sys/resource.h>
104 # include <pthread.h>
105 # include <sys/stat.h>
106 # include <sys/time.h>
107 # include <sys/times.h>
108 # include <sys/utsname.h>
109 # include <sys/socket.h>
110 # include <sys/wait.h>
111 # include <pwd.h>
112 # include <poll.h>
113 # include <semaphore.h>
114 # include <fcntl.h>
115 # include <string.h>
116 # include <syscall.h>
117 # include <sys/sysinfo.h>
118 # include <gnu/libc-version.h>
119 # include <sys/ipc.h>
120 # include <sys/shm.h>
121 # include <link.h>
122 # include <stdint.h>
123 # include <inttypes.h>
124 # include <sys/ioctl.h>
125
126 #define MAX_PATH (2 * K)
127
128 // for timer info max values which include all bits
129 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
130
131 #define LARGEPAGES_BIT (1 << 6)
132 ////////////////////////////////////////////////////////////////////////////////
133 // global variables
134 julong os::Linux::_physical_memory = 0;
135
136 address os::Linux::_initial_thread_stack_bottom = NULL;
137 uintptr_t os::Linux::_initial_thread_stack_size = 0;
138
139 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
140 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
141 Mutex* os::Linux::_createThread_lock = NULL;
142 pthread_t os::Linux::_main_thread;
143 int os::Linux::_page_size = -1;
144 bool os::Linux::_is_floating_stack = false;
145 bool os::Linux::_is_NPTL = false;
146 bool os::Linux::_supports_fast_thread_cpu_time = false;
147 const char * os::Linux::_glibc_version = NULL;
148 const char * os::Linux::_libpthread_version = NULL;
149
150 static jlong initial_time_count=0;
151
152 static int clock_tics_per_sec = 100;
153
154 // For diagnostics to print a message once. see run_periodic_checks
155 static sigset_t check_signal_done;
156 static bool check_signals = true;;
157
158 static pid_t _initial_pid = 0;
159
160 /* Signal number used to suspend/resume a thread */
161
162 /* do not use any signal number less than SIGSEGV, see 4355769 */
163 static int SR_signum = SIGUSR2;
164 sigset_t SR_sigset;
165
166 /* Used to protect dlsym() calls */
167 static pthread_mutex_t dl_mutex;
168
169 #ifdef JAVASE_EMBEDDED
170 class MemNotifyThread: public Thread {
171 friend class VMStructs;
172 public:
173 virtual void run();
174
175 private:
176 static MemNotifyThread* _memnotify_thread;
177 int _fd;
178
179 public:
180
181 // Constructor
182 MemNotifyThread(int fd);
183
184 // Tester
185 bool is_memnotify_thread() const { return true; }
186
187 // Printing
188 char* name() const { return (char*)"Linux MemNotify Thread"; }
189
190 // Returns the single instance of the MemNotifyThread
191 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }
192
193 // Create and start the single instance of MemNotifyThread
194 static void start();
195 };
196 #endif // JAVASE_EMBEDDED
197
198 // utility functions
199
200 static int SR_initialize();
201 static int SR_finalize();
202
203 julong os::available_memory() {
204 return Linux::available_memory();
205 }
206
207 julong os::Linux::available_memory() {
208 // values in struct sysinfo are "unsigned long"
209 struct sysinfo si;
210 sysinfo(&si);
211
212 return (julong)si.freeram * si.mem_unit;
213 }
214
215 julong os::physical_memory() {
216 return Linux::physical_memory();
217 }
218
219 julong os::allocatable_physical_memory(julong size) {
220 #ifdef _LP64
221 return size;
222 #else
223 julong result = MIN2(size, (julong)3800*M);
224 if (!is_allocatable(result)) {
225 // See comments under solaris for alignment considerations
226 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
227 result = MIN2(size, reasonable_size);
228 }
229 return result;
230 #endif // _LP64
231 }
232
233 ////////////////////////////////////////////////////////////////////////////////
234 // environment support
235
236 bool os::getenv(const char* name, char* buf, int len) {
237 const char* val = ::getenv(name);
238 if (val != NULL && strlen(val) < (size_t)len) {
239 strcpy(buf, val);
240 return true;
241 }
242 if (len > 0) buf[0] = 0; // return a null string
243 return false;
244 }
245
246
247 // Return true if user is running as root.
248
249 bool os::have_special_privileges() {
250 static bool init = false;
251 static bool privileges = false;
252 if (!init) {
253 privileges = (getuid() != geteuid()) || (getgid() != getegid());
254 init = true;
255 }
256 return privileges;
257 }
258
259
260 #ifndef SYS_gettid
261 // i386: 224, ia64: 1105, amd64: 186, sparc 143
262 #ifdef __ia64__
263 #define SYS_gettid 1105
264 #elif __i386__
265 #define SYS_gettid 224
266 #elif __amd64__
267 #define SYS_gettid 186
268 #elif __sparc__
269 #define SYS_gettid 143
270 #else
271 #error define gettid for the arch
272 #endif
273 #endif
274
275 // Cpu architecture string
276 #if defined(ZERO)
277 static char cpu_arch[] = ZERO_LIBARCH;
278 #elif defined(IA64)
279 static char cpu_arch[] = "ia64";
280 #elif defined(IA32)
281 static char cpu_arch[] = "i386";
282 #elif defined(AMD64)
283 static char cpu_arch[] = "amd64";
284 #elif defined(ARM)
285 static char cpu_arch[] = "arm";
286 #elif defined(PPC)
287 static char cpu_arch[] = "ppc";
288 #elif defined(SPARC)
289 # ifdef _LP64
290 static char cpu_arch[] = "sparcv9";
291 # else
292 static char cpu_arch[] = "sparc";
293 # endif
294 #else
295 #error Add appropriate cpu_arch setting
296 #endif
297
298
299 // pid_t gettid()
300 //
301 // Returns the kernel thread id of the currently running thread. Kernel
302 // thread id is used to access /proc.
303 //
304 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
305 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
306 //
307 pid_t os::Linux::gettid() {
308 int rslt = syscall(SYS_gettid);
309 if (rslt == -1) {
310 // old kernel, no NPTL support
311 return getpid();
312 } else {
313 return (pid_t)rslt;
314 }
315 }
316
317 // Most versions of linux have a bug where the number of processors are
318 // determined by looking at the /proc file system. In a chroot environment,
319 // the system call returns 1. This causes the VM to act as if it is
320 // a single processor and elide locking (see is_MP() call).
321 static bool unsafe_chroot_detected = false;
322 static const char *unstable_chroot_error = "/proc file system not found.\n"
323 "Java may be unstable running multithreaded in a chroot "
324 "environment on Linux when /proc filesystem is not mounted.";
325
326 void os::Linux::initialize_system_info() {
327 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
328 if (processor_count() == 1) {
329 pid_t pid = os::Linux::gettid();
330 char fname[32];
331 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
332 FILE *fp = fopen(fname, "r");
333 if (fp == NULL) {
334 unsafe_chroot_detected = true;
335 } else {
336 fclose(fp);
337 }
338 }
339 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
340 assert(processor_count() > 0, "linux error");
341 }
342
343 void os::init_system_properties_values() {
344 // char arch[12];
345 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
346
347 // The next steps are taken in the product version:
348 //
349 // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
350 // This library should be located at:
351 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
352 //
353 // If "/jre/lib/" appears at the right place in the path, then we
354 // assume libjvm[_g].so is installed in a JDK and we use this path.
355 //
356 // Otherwise exit with message: "Could not create the Java virtual machine."
357 //
358 // The following extra steps are taken in the debugging version:
359 //
360 // If "/jre/lib/" does NOT appear at the right place in the path
361 // instead of exit check for $JAVA_HOME environment variable.
362 //
363 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
364 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
365 // it looks like libjvm[_g].so is installed there
366 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
367 //
368 // Otherwise exit.
369 //
370 // Important note: if the location of libjvm.so changes this
371 // code needs to be changed accordingly.
372
373 // The next few definitions allow the code to be verbatim:
374 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n), mtInternal)
375 #define getenv(n) ::getenv(n)
376
377 /*
378 * See ld(1):
379 * The linker uses the following search paths to locate required
380 * shared libraries:
381 * 1: ...
382 * ...
383 * 7: The default directories, normally /lib and /usr/lib.
384 */
385 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
386 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
387 #else
388 #define DEFAULT_LIBPATH "/lib:/usr/lib"
389 #endif
390
391 #define EXTENSIONS_DIR "/lib/ext"
392 #define ENDORSED_DIR "/lib/endorsed"
393 #define REG_DIR "/usr/java/packages"
394
395 {
396 /* sysclasspath, java_home, dll_dir */
397 {
398 char *home_path;
399 char *dll_path;
400 char *pslash;
401 char buf[MAXPATHLEN];
402 os::jvm_path(buf, sizeof(buf));
403
404 // Found the full path to libjvm.so.
405 // Now cut the path to <java_home>/jre if we can.
406 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
407 pslash = strrchr(buf, '/');
408 if (pslash != NULL)
409 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
410 dll_path = malloc(strlen(buf) + 1);
411 if (dll_path == NULL)
412 return;
413 strcpy(dll_path, buf);
414 Arguments::set_dll_dir(dll_path);
415
416 if (pslash != NULL) {
417 pslash = strrchr(buf, '/');
418 if (pslash != NULL) {
419 *pslash = '\0'; /* get rid of /<arch> */
420 pslash = strrchr(buf, '/');
421 if (pslash != NULL)
422 *pslash = '\0'; /* get rid of /lib */
423 }
424 }
425
426 home_path = malloc(strlen(buf) + 1);
427 if (home_path == NULL)
428 return;
429 strcpy(home_path, buf);
430 Arguments::set_java_home(home_path);
431
432 if (!set_boot_path('/', ':'))
433 return;
434 }
435
436 /*
437 * Where to look for native libraries
438 *
439 * Note: Due to a legacy implementation, most of the library path
440 * is set in the launcher. This was to accomodate linking restrictions
441 * on legacy Linux implementations (which are no longer supported).
442 * Eventually, all the library path setting will be done here.
443 *
444 * However, to prevent the proliferation of improperly built native
445 * libraries, the new path component /usr/java/packages is added here.
446 * Eventually, all the library path setting will be done here.
447 */
448 {
449 char *ld_library_path;
450
451 /*
452 * Construct the invariant part of ld_library_path. Note that the
453 * space for the colon and the trailing null are provided by the
454 * nulls included by the sizeof operator (so actually we allocate
455 * a byte more than necessary).
456 */
457 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
458 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
459 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
460
461 /*
462 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
463 * should always exist (until the legacy problem cited above is
464 * addressed).
465 */
466 char *v = getenv("LD_LIBRARY_PATH");
467 if (v != NULL) {
468 char *t = ld_library_path;
469 /* That's +1 for the colon and +1 for the trailing '\0' */
470 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
471 sprintf(ld_library_path, "%s:%s", v, t);
472 }
473 Arguments::set_library_path(ld_library_path);
474 }
475
476 /*
477 * Extensions directories.
478 *
479 * Note that the space for the colon and the trailing null are provided
480 * by the nulls included by the sizeof operator (so actually one byte more
481 * than necessary is allocated).
482 */
483 {
484 char *buf = malloc(strlen(Arguments::get_java_home()) +
485 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
486 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
487 Arguments::get_java_home());
488 Arguments::set_ext_dirs(buf);
489 }
490
491 /* Endorsed standards default directory. */
492 {
493 char * buf;
494 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
495 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
496 Arguments::set_endorsed_dirs(buf);
497 }
498 }
499
500 #undef malloc
501 #undef getenv
502 #undef EXTENSIONS_DIR
503 #undef ENDORSED_DIR
504
505 // Done
506 return;
507 }
508
509 ////////////////////////////////////////////////////////////////////////////////
510 // breakpoint support
511
512 void os::breakpoint() {
513 BREAKPOINT;
514 }
515
516 extern "C" void breakpoint() {
517 // use debugger to set breakpoint here
518 }
519
520 ////////////////////////////////////////////////////////////////////////////////
521 // signal support
522
523 debug_only(static bool signal_sets_initialized = false);
524 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
525
526 bool os::Linux::is_sig_ignored(int sig) {
527 struct sigaction oact;
528 sigaction(sig, (struct sigaction*)NULL, &oact);
529 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
530 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
531 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
532 return true;
533 else
534 return false;
535 }
536
537 void os::Linux::signal_sets_init() {
538 // Should also have an assertion stating we are still single-threaded.
539 assert(!signal_sets_initialized, "Already initialized");
540 // Fill in signals that are necessarily unblocked for all threads in
541 // the VM. Currently, we unblock the following signals:
542 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
543 // by -Xrs (=ReduceSignalUsage));
544 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
545 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
546 // the dispositions or masks wrt these signals.
547 // Programs embedding the VM that want to use the above signals for their
548 // own purposes must, at this time, use the "-Xrs" option to prevent
549 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
550 // (See bug 4345157, and other related bugs).
551 // In reality, though, unblocking these signals is really a nop, since
552 // these signals are not blocked by default.
553 sigemptyset(&unblocked_sigs);
554 sigemptyset(&allowdebug_blocked_sigs);
555 sigaddset(&unblocked_sigs, SIGILL);
556 sigaddset(&unblocked_sigs, SIGSEGV);
557 sigaddset(&unblocked_sigs, SIGBUS);
558 sigaddset(&unblocked_sigs, SIGFPE);
559 sigaddset(&unblocked_sigs, SR_signum);
560
561 if (!ReduceSignalUsage) {
562 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
563 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
564 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
565 }
566 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
567 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
568 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
569 }
570 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
571 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
572 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
573 }
574 }
575 // Fill in signals that are blocked by all but the VM thread.
576 sigemptyset(&vm_sigs);
577 if (!ReduceSignalUsage)
578 sigaddset(&vm_sigs, BREAK_SIGNAL);
579 debug_only(signal_sets_initialized = true);
580
581 }
582
583 // These are signals that are unblocked while a thread is running Java.
584 // (For some reason, they get blocked by default.)
585 sigset_t* os::Linux::unblocked_signals() {
586 assert(signal_sets_initialized, "Not initialized");
587 return &unblocked_sigs;
588 }
589
590 // These are the signals that are blocked while a (non-VM) thread is
591 // running Java. Only the VM thread handles these signals.
592 sigset_t* os::Linux::vm_signals() {
593 assert(signal_sets_initialized, "Not initialized");
594 return &vm_sigs;
595 }
596
597 // These are signals that are blocked during cond_wait to allow debugger in
598 sigset_t* os::Linux::allowdebug_blocked_signals() {
599 assert(signal_sets_initialized, "Not initialized");
600 return &allowdebug_blocked_sigs;
601 }
602
603 void os::Linux::hotspot_sigmask(Thread* thread) {
604
605 //Save caller's signal mask before setting VM signal mask
606 sigset_t caller_sigmask;
607 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
608
609 OSThread* osthread = thread->osthread();
610 osthread->set_caller_sigmask(caller_sigmask);
611
612 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
613
614 if (!ReduceSignalUsage) {
615 if (thread->is_VM_thread()) {
616 // Only the VM thread handles BREAK_SIGNAL ...
617 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
618 } else {
619 // ... all other threads block BREAK_SIGNAL
620 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
621 }
622 }
623 }
624
625 //////////////////////////////////////////////////////////////////////////////
626 // detecting pthread library
627
628 void os::Linux::libpthread_init() {
629 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
630 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
631 // generic name for earlier versions.
632 // Define macros here so we can build HotSpot on old systems.
633 # ifndef _CS_GNU_LIBC_VERSION
634 # define _CS_GNU_LIBC_VERSION 2
635 # endif
636 # ifndef _CS_GNU_LIBPTHREAD_VERSION
637 # define _CS_GNU_LIBPTHREAD_VERSION 3
638 # endif
639
640 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
641 if (n > 0) {
642 char *str = (char *)malloc(n, mtInternal);
643 confstr(_CS_GNU_LIBC_VERSION, str, n);
644 os::Linux::set_glibc_version(str);
645 } else {
646 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
647 static char _gnu_libc_version[32];
648 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
649 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
650 os::Linux::set_glibc_version(_gnu_libc_version);
651 }
652
653 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
654 if (n > 0) {
655 char *str = (char *)malloc(n, mtInternal);
656 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
657 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
658 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
659 // is the case. LinuxThreads has a hard limit on max number of threads.
660 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
661 // On the other hand, NPTL does not have such a limit, sysconf()
662 // will return -1 and errno is not changed. Check if it is really NPTL.
663 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
664 strstr(str, "NPTL") &&
665 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
666 free(str);
667 os::Linux::set_libpthread_version("linuxthreads");
668 } else {
669 os::Linux::set_libpthread_version(str);
670 }
671 } else {
672 // glibc before 2.3.2 only has LinuxThreads.
673 os::Linux::set_libpthread_version("linuxthreads");
674 }
675
676 if (strstr(libpthread_version(), "NPTL")) {
677 os::Linux::set_is_NPTL();
678 } else {
679 os::Linux::set_is_LinuxThreads();
680 }
681
682 // LinuxThreads have two flavors: floating-stack mode, which allows variable
683 // stack size; and fixed-stack mode. NPTL is always floating-stack.
684 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
685 os::Linux::set_is_floating_stack();
686 }
687 }
688
689 /////////////////////////////////////////////////////////////////////////////
690 // thread stack
691
692 // Force Linux kernel to expand current thread stack. If "bottom" is close
693 // to the stack guard, caller should block all signals.
694 //
695 // MAP_GROWSDOWN:
696 // A special mmap() flag that is used to implement thread stacks. It tells
697 // kernel that the memory region should extend downwards when needed. This
698 // allows early versions of LinuxThreads to only mmap the first few pages
699 // when creating a new thread. Linux kernel will automatically expand thread
700 // stack as needed (on page faults).
701 //
702 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
703 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
704 // region, it's hard to tell if the fault is due to a legitimate stack
705 // access or because of reading/writing non-exist memory (e.g. buffer
706 // overrun). As a rule, if the fault happens below current stack pointer,
707 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
708 // application (see Linux kernel fault.c).
709 //
710 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
711 // stack overflow detection.
712 //
713 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
714 // not use this flag. However, the stack of initial thread is not created
715 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
716 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
717 // and then attach the thread to JVM.
718 //
719 // To get around the problem and allow stack banging on Linux, we need to
720 // manually expand thread stack after receiving the SIGSEGV.
721 //
722 // There are two ways to expand thread stack to address "bottom", we used
723 // both of them in JVM before 1.5:
724 // 1. adjust stack pointer first so that it is below "bottom", and then
725 // touch "bottom"
726 // 2. mmap() the page in question
727 //
728 // Now alternate signal stack is gone, it's harder to use 2. For instance,
729 // if current sp is already near the lower end of page 101, and we need to
730 // call mmap() to map page 100, it is possible that part of the mmap() frame
731 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
732 // That will destroy the mmap() frame and cause VM to crash.
733 //
734 // The following code works by adjusting sp first, then accessing the "bottom"
735 // page to force a page fault. Linux kernel will then automatically expand the
736 // stack mapping.
737 //
738 // _expand_stack_to() assumes its frame size is less than page size, which
739 // should always be true if the function is not inlined.
740
741 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
742 #define NOINLINE
743 #else
744 #define NOINLINE __attribute__ ((noinline))
745 #endif
746
747 static void _expand_stack_to(address bottom) NOINLINE;
748
749 static void _expand_stack_to(address bottom) {
750 address sp;
751 size_t size;
752 volatile char *p;
753
754 // Adjust bottom to point to the largest address within the same page, it
755 // gives us a one-page buffer if alloca() allocates slightly more memory.
756 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
757 bottom += os::Linux::page_size() - 1;
758
759 // sp might be slightly above current stack pointer; if that's the case, we
760 // will alloca() a little more space than necessary, which is OK. Don't use
761 // os::current_stack_pointer(), as its result can be slightly below current
762 // stack pointer, causing us to not alloca enough to reach "bottom".
763 sp = (address)&sp;
764
765 if (sp > bottom) {
766 size = sp - bottom;
767 p = (volatile char *)alloca(size);
768 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
769 p[0] = '\0';
770 }
771 }
772
773 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
774 assert(t!=NULL, "just checking");
775 assert(t->osthread()->expanding_stack(), "expand should be set");
776 assert(t->stack_base() != NULL, "stack_base was not initialized");
777
778 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
779 sigset_t mask_all, old_sigset;
780 sigfillset(&mask_all);
781 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
782 _expand_stack_to(addr);
783 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
784 return true;
785 }
786 return false;
787 }
788
789 //////////////////////////////////////////////////////////////////////////////
790 // create new thread
791
792 static address highest_vm_reserved_address();
793
794 // check if it's safe to start a new thread
795 static bool _thread_safety_check(Thread* thread) {
796 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
797 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
798 // Heap is mmap'ed at lower end of memory space. Thread stacks are
799 // allocated (MAP_FIXED) from high address space. Every thread stack
800 // occupies a fixed size slot (usually 2Mbytes, but user can change
801 // it to other values if they rebuild LinuxThreads).
802 //
803 // Problem with MAP_FIXED is that mmap() can still succeed even part of
804 // the memory region has already been mmap'ed. That means if we have too
805 // many threads and/or very large heap, eventually thread stack will
806 // collide with heap.
807 //
808 // Here we try to prevent heap/stack collision by comparing current
809 // stack bottom with the highest address that has been mmap'ed by JVM
810 // plus a safety margin for memory maps created by native code.
811 //
812 // This feature can be disabled by setting ThreadSafetyMargin to 0
813 //
814 if (ThreadSafetyMargin > 0) {
815 address stack_bottom = os::current_stack_base() - os::current_stack_size();
816
817 // not safe if our stack extends below the safety margin
818 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
819 } else {
820 return true;
821 }
822 } else {
823 // Floating stack LinuxThreads or NPTL:
824 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
825 // there's not enough space left, pthread_create() will fail. If we come
826 // here, that means enough space has been reserved for stack.
827 return true;
828 }
829 }
830
831 // Thread start routine for all newly created threads
832 static void *java_start(Thread *thread) {
833 // Try to randomize the cache line index of hot stack frames.
834 // This helps when threads of the same stack traces evict each other's
835 // cache lines. The threads can be either from the same JVM instance, or
836 // from different JVM instances. The benefit is especially true for
837 // processors with hyperthreading technology.
838 static int counter = 0;
839 int pid = os::current_process_id();
840 alloca(((pid ^ counter++) & 7) * 128);
841
842 ThreadLocalStorage::set_thread(thread);
843
844 OSThread* osthread = thread->osthread();
845 Monitor* sync = osthread->startThread_lock();
846
847 // non floating stack LinuxThreads needs extra check, see above
848 if (!_thread_safety_check(thread)) {
849 // notify parent thread
850 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
851 osthread->set_state(ZOMBIE);
852 sync->notify_all();
853 return NULL;
854 }
855
856 // thread_id is kernel thread id (similar to Solaris LWP id)
857 osthread->set_thread_id(os::Linux::gettid());
858
859 if (UseNUMA) {
860 int lgrp_id = os::numa_get_group_id();
861 if (lgrp_id != -1) {
862 thread->set_lgrp_id(lgrp_id);
863 }
864 }
865 // initialize signal mask for this thread
866 os::Linux::hotspot_sigmask(thread);
867
868 // initialize floating point control register
869 os::Linux::init_thread_fpu_state();
870
871 // handshaking with parent thread
872 {
873 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
874
875 // notify parent thread
876 osthread->set_state(INITIALIZED);
877 sync->notify_all();
878
879 // wait until os::start_thread()
880 while (osthread->get_state() == INITIALIZED) {
881 sync->wait(Mutex::_no_safepoint_check_flag);
882 }
883 }
884
885 // call one more level start routine
886 thread->run();
887
888 return 0;
889 }
890
891 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
892 assert(thread->osthread() == NULL, "caller responsible");
893
894 // Allocate the OSThread object
895 OSThread* osthread = new OSThread(NULL, NULL);
896 if (osthread == NULL) {
897 return false;
898 }
899
900 // set the correct thread state
901 osthread->set_thread_type(thr_type);
902
903 // Initial state is ALLOCATED but not INITIALIZED
904 osthread->set_state(ALLOCATED);
905
906 thread->set_osthread(osthread);
907
908 // init thread attributes
909 pthread_attr_t attr;
910 pthread_attr_init(&attr);
911 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
912
913 // stack size
914 if (os::Linux::supports_variable_stack_size()) {
915 // calculate stack size if it's not specified by caller
916 if (stack_size == 0) {
917 stack_size = os::Linux::default_stack_size(thr_type);
918
919 switch (thr_type) {
920 case os::java_thread:
921 // Java threads use ThreadStackSize which default value can be
922 // changed with the flag -Xss
923 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
924 stack_size = JavaThread::stack_size_at_create();
925 break;
926 case os::compiler_thread:
927 if (CompilerThreadStackSize > 0) {
928 stack_size = (size_t)(CompilerThreadStackSize * K);
929 break;
930 } // else fall through:
931 // use VMThreadStackSize if CompilerThreadStackSize is not defined
932 case os::vm_thread:
933 case os::pgc_thread:
934 case os::cgc_thread:
935 case os::watcher_thread:
936 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
937 break;
938 }
939 }
940
941 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
942 pthread_attr_setstacksize(&attr, stack_size);
943 } else {
944 // let pthread_create() pick the default value.
945 }
946
947 // glibc guard page
948 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
949
950 ThreadState state;
951
952 {
953 // Serialize thread creation if we are running with fixed stack LinuxThreads
954 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
955 if (lock) {
956 os::Linux::createThread_lock()->lock_without_safepoint_check();
957 }
958
959 pthread_t tid;
960 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
961
962 pthread_attr_destroy(&attr);
963
964 if (ret != 0) {
965 if (PrintMiscellaneous && (Verbose || WizardMode)) {
966 perror("pthread_create()");
967 }
968 // Need to clean up stuff we've allocated so far
969 thread->set_osthread(NULL);
970 delete osthread;
971 if (lock) os::Linux::createThread_lock()->unlock();
972 return false;
973 }
974
975 // Store pthread info into the OSThread
976 osthread->set_pthread_id(tid);
977
978 // Wait until child thread is either initialized or aborted
979 {
980 Monitor* sync_with_child = osthread->startThread_lock();
981 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
982 while ((state = osthread->get_state()) == ALLOCATED) {
983 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
984 }
985 }
986
987 if (lock) {
988 os::Linux::createThread_lock()->unlock();
989 }
990 }
991
992 // Aborted due to thread limit being reached
993 if (state == ZOMBIE) {
994 thread->set_osthread(NULL);
995 delete osthread;
996 return false;
997 }
998
999 // The thread is returned suspended (in state INITIALIZED),
1000 // and is started higher up in the call chain
1001 assert(state == INITIALIZED, "race condition");
1002 return true;
1003 }
1004
1005 /////////////////////////////////////////////////////////////////////////////
1006 // attach existing thread
1007
1008 // bootstrap the main thread
1009 bool os::create_main_thread(JavaThread* thread) {
1010 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
1011 return create_attached_thread(thread);
1012 }
1013
1014 bool os::create_attached_thread(JavaThread* thread) {
1015 #ifdef ASSERT
1016 thread->verify_not_published();
1017 #endif
1018
1019 // Allocate the OSThread object
1020 OSThread* osthread = new OSThread(NULL, NULL);
1021
1022 if (osthread == NULL) {
1023 return false;
1024 }
1025
1026 // Store pthread info into the OSThread
1027 osthread->set_thread_id(os::Linux::gettid());
1028 osthread->set_pthread_id(::pthread_self());
1029
1030 // initialize floating point control register
1031 os::Linux::init_thread_fpu_state();
1032
1033 // Initial thread state is RUNNABLE
1034 osthread->set_state(RUNNABLE);
1035
1036 thread->set_osthread(osthread);
1037
1038 if (UseNUMA) {
1039 int lgrp_id = os::numa_get_group_id();
1040 if (lgrp_id != -1) {
1041 thread->set_lgrp_id(lgrp_id);
1042 }
1043 }
1044
1045 if (os::Linux::is_initial_thread()) {
1046 // If current thread is initial thread, its stack is mapped on demand,
1047 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1048 // the entire stack region to avoid SEGV in stack banging.
1049 // It is also useful to get around the heap-stack-gap problem on SuSE
1050 // kernel (see 4821821 for details). We first expand stack to the top
1051 // of yellow zone, then enable stack yellow zone (order is significant,
1052 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1053 // is no gap between the last two virtual memory regions.
1054
1055 JavaThread *jt = (JavaThread *)thread;
1056 address addr = jt->stack_yellow_zone_base();
1057 assert(addr != NULL, "initialization problem?");
1058 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1059
1060 osthread->set_expanding_stack();
1061 os::Linux::manually_expand_stack(jt, addr);
1062 osthread->clear_expanding_stack();
1063 }
1064
1065 // initialize signal mask for this thread
1066 // and save the caller's signal mask
1067 os::Linux::hotspot_sigmask(thread);
1068
1069 return true;
1070 }
1071
1072 void os::pd_start_thread(Thread* thread) {
1073 OSThread * osthread = thread->osthread();
1074 assert(osthread->get_state() != INITIALIZED, "just checking");
1075 Monitor* sync_with_child = osthread->startThread_lock();
1076 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1077 sync_with_child->notify();
1078 }
1079
1080 // Free Linux resources related to the OSThread
1081 void os::free_thread(OSThread* osthread) {
1082 assert(osthread != NULL, "osthread not set");
1083
1084 if (Thread::current()->osthread() == osthread) {
1085 // Restore caller's signal mask
1086 sigset_t sigmask = osthread->caller_sigmask();
1087 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1088 }
1089
1090 delete osthread;
1091 }
1092
1093 //////////////////////////////////////////////////////////////////////////////
1094 // thread local storage
1095
1096 int os::allocate_thread_local_storage() {
1097 pthread_key_t key;
1098 int rslt = pthread_key_create(&key, NULL);
1099 assert(rslt == 0, "cannot allocate thread local storage");
1100 return (int)key;
1101 }
1102
1103 // Note: This is currently not used by VM, as we don't destroy TLS key
1104 // on VM exit.
1105 void os::free_thread_local_storage(int index) {
1106 int rslt = pthread_key_delete((pthread_key_t)index);
1107 assert(rslt == 0, "invalid index");
1108 }
1109
1110 void os::thread_local_storage_at_put(int index, void* value) {
1111 int rslt = pthread_setspecific((pthread_key_t)index, value);
1112 assert(rslt == 0, "pthread_setspecific failed");
1113 }
1114
1115 extern "C" Thread* get_thread() {
1116 return ThreadLocalStorage::thread();
1117 }
1118
1119 //////////////////////////////////////////////////////////////////////////////
1120 // initial thread
1121
1122 // Check if current thread is the initial thread, similar to Solaris thr_main.
1123 bool os::Linux::is_initial_thread(void) {
1124 char dummy;
1125 // If called before init complete, thread stack bottom will be null.
1126 // Can be called if fatal error occurs before initialization.
1127 if (initial_thread_stack_bottom() == NULL) return false;
1128 assert(initial_thread_stack_bottom() != NULL &&
1129 initial_thread_stack_size() != 0,
1130 "os::init did not locate initial thread's stack region");
1131 if ((address)&dummy >= initial_thread_stack_bottom() &&
1132 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1133 return true;
1134 else return false;
1135 }
1136
1137 // Find the virtual memory area that contains addr
1138 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1139 FILE *fp = fopen("/proc/self/maps", "r");
1140 if (fp) {
1141 address low, high;
1142 while (!feof(fp)) {
1143 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1144 if (low <= addr && addr < high) {
1145 if (vma_low) *vma_low = low;
1146 if (vma_high) *vma_high = high;
1147 fclose (fp);
1148 return true;
1149 }
1150 }
1151 for (;;) {
1152 int ch = fgetc(fp);
1153 if (ch == EOF || ch == (int)'\n') break;
1154 }
1155 }
1156 fclose(fp);
1157 }
1158 return false;
1159 }
1160
1161 // Locate initial thread stack. This special handling of initial thread stack
1162 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1163 // bogus value for initial thread.
1164 void os::Linux::capture_initial_stack(size_t max_size) {
1165 // stack size is the easy part, get it from RLIMIT_STACK
1166 size_t stack_size;
1167 struct rlimit rlim;
1168 getrlimit(RLIMIT_STACK, &rlim);
1169 stack_size = rlim.rlim_cur;
1170
1171 // 6308388: a bug in ld.so will relocate its own .data section to the
1172 // lower end of primordial stack; reduce ulimit -s value a little bit
1173 // so we won't install guard page on ld.so's data section.
1174 stack_size -= 2 * page_size();
1175
1176 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1177 // 7.1, in both cases we will get 2G in return value.
1178 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1179 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1180 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1181 // in case other parts in glibc still assumes 2M max stack size.
1182 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1183 #ifndef IA64
1184 if (stack_size > 2 * K * K) stack_size = 2 * K * K;
1185 #else
1186 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1187 if (stack_size > 4 * K * K) stack_size = 4 * K * K;
1188 #endif
1189
1190 // Try to figure out where the stack base (top) is. This is harder.
1191 //
1192 // When an application is started, glibc saves the initial stack pointer in
1193 // a global variable "__libc_stack_end", which is then used by system
1194 // libraries. __libc_stack_end should be pretty close to stack top. The
1195 // variable is available since the very early days. However, because it is
1196 // a private interface, it could disappear in the future.
1197 //
1198 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1199 // to __libc_stack_end, it is very close to stack top, but isn't the real
1200 // stack top. Note that /proc may not exist if VM is running as a chroot
1201 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1202 // /proc/<pid>/stat could change in the future (though unlikely).
1203 //
1204 // We try __libc_stack_end first. If that doesn't work, look for
1205 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1206 // as a hint, which should work well in most cases.
1207
1208 uintptr_t stack_start;
1209
1210 // try __libc_stack_end first
1211 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1212 if (p && *p) {
1213 stack_start = *p;
1214 } else {
1215 // see if we can get the start_stack field from /proc/self/stat
1216 FILE *fp;
1217 int pid;
1218 char state;
1219 int ppid;
1220 int pgrp;
1221 int session;
1222 int nr;
1223 int tpgrp;
1224 unsigned long flags;
1225 unsigned long minflt;
1226 unsigned long cminflt;
1227 unsigned long majflt;
1228 unsigned long cmajflt;
1229 unsigned long utime;
1230 unsigned long stime;
1231 long cutime;
1232 long cstime;
1233 long prio;
1234 long nice;
1235 long junk;
1236 long it_real;
1237 uintptr_t start;
1238 uintptr_t vsize;
1239 intptr_t rss;
1240 uintptr_t rsslim;
1241 uintptr_t scodes;
1242 uintptr_t ecode;
1243 int i;
1244
1245 // Figure what the primordial thread stack base is. Code is inspired
1246 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1247 // followed by command name surrounded by parentheses, state, etc.
1248 char stat[2048];
1249 int statlen;
1250
1251 fp = fopen("/proc/self/stat", "r");
1252 if (fp) {
1253 statlen = fread(stat, 1, 2047, fp);
1254 stat[statlen] = '\0';
1255 fclose(fp);
1256
1257 // Skip pid and the command string. Note that we could be dealing with
1258 // weird command names, e.g. user could decide to rename java launcher
1259 // to "java 1.4.2 :)", then the stat file would look like
1260 // 1234 (java 1.4.2 :)) R ... ...
1261 // We don't really need to know the command string, just find the last
1262 // occurrence of ")" and then start parsing from there. See bug 4726580.
1263 char * s = strrchr(stat, ')');
1264
1265 i = 0;
1266 if (s) {
1267 // Skip blank chars
1268 do s++; while (isspace(*s));
1269
1270 #define _UFM UINTX_FORMAT
1271 #define _DFM INTX_FORMAT
1272
1273 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1274 /* 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 */
1275 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM,
1276 &state, /* 3 %c */
1277 &ppid, /* 4 %d */
1278 &pgrp, /* 5 %d */
1279 &session, /* 6 %d */
1280 &nr, /* 7 %d */
1281 &tpgrp, /* 8 %d */
1282 &flags, /* 9 %lu */
1283 &minflt, /* 10 %lu */
1284 &cminflt, /* 11 %lu */
1285 &majflt, /* 12 %lu */
1286 &cmajflt, /* 13 %lu */
1287 &utime, /* 14 %lu */
1288 &stime, /* 15 %lu */
1289 &cutime, /* 16 %ld */
1290 &cstime, /* 17 %ld */
1291 &prio, /* 18 %ld */
1292 &nice, /* 19 %ld */
1293 &junk, /* 20 %ld */
1294 &it_real, /* 21 %ld */
1295 &start, /* 22 UINTX_FORMAT */
1296 &vsize, /* 23 UINTX_FORMAT */
1297 &rss, /* 24 INTX_FORMAT */
1298 &rsslim, /* 25 UINTX_FORMAT */
1299 &scodes, /* 26 UINTX_FORMAT */
1300 &ecode, /* 27 UINTX_FORMAT */
1301 &stack_start); /* 28 UINTX_FORMAT */
1302 }
1303
1304 #undef _UFM
1305 #undef _DFM
1306
1307 if (i != 28 - 2) {
1308 assert(false, "Bad conversion from /proc/self/stat");
1309 // product mode - assume we are the initial thread, good luck in the
1310 // embedded case.
1311 warning("Can't detect initial thread stack location - bad conversion");
1312 stack_start = (uintptr_t) &rlim;
1313 }
1314 } else {
1315 // For some reason we can't open /proc/self/stat (for example, running on
1316 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1317 // most cases, so don't abort:
1318 warning("Can't detect initial thread stack location - no /proc/self/stat");
1319 stack_start = (uintptr_t) &rlim;
1320 }
1321 }
1322
1323 // Now we have a pointer (stack_start) very close to the stack top, the
1324 // next thing to do is to figure out the exact location of stack top. We
1325 // can find out the virtual memory area that contains stack_start by
1326 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1327 // and its upper limit is the real stack top. (again, this would fail if
1328 // running inside chroot, because /proc may not exist.)
1329
1330 uintptr_t stack_top;
1331 address low, high;
1332 if (find_vma((address)stack_start, &low, &high)) {
1333 // success, "high" is the true stack top. (ignore "low", because initial
1334 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1335 stack_top = (uintptr_t)high;
1336 } else {
1337 // failed, likely because /proc/self/maps does not exist
1338 warning("Can't detect initial thread stack location - find_vma failed");
1339 // best effort: stack_start is normally within a few pages below the real
1340 // stack top, use it as stack top, and reduce stack size so we won't put
1341 // guard page outside stack.
1342 stack_top = stack_start;
1343 stack_size -= 16 * page_size();
1344 }
1345
1346 // stack_top could be partially down the page so align it
1347 stack_top = align_size_up(stack_top, page_size());
1348
1349 if (max_size && stack_size > max_size) {
1350 _initial_thread_stack_size = max_size;
1351 } else {
1352 _initial_thread_stack_size = stack_size;
1353 }
1354
1355 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1356 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1357 }
1358
1359 ////////////////////////////////////////////////////////////////////////////////
1360 // time support
1361
1362 // Time since start-up in seconds to a fine granularity.
1363 // Used by VMSelfDestructTimer and the MemProfiler.
1364 double os::elapsedTime() {
1365
1366 return (double)(os::elapsed_counter()) * 0.000001;
1367 }
1368
1369 jlong os::elapsed_counter() {
1370 timeval time;
1371 int status = gettimeofday(&time, NULL);
1372 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1373 }
1374
1375 jlong os::elapsed_frequency() {
1376 return (1000 * 1000);
1377 }
1378
1379 // For now, we say that linux does not support vtime. I have no idea
1380 // whether it can actually be made to (DLD, 9/13/05).
1381
1382 bool os::supports_vtime() { return false; }
1383 bool os::enable_vtime() { return false; }
1384 bool os::vtime_enabled() { return false; }
1385 double os::elapsedVTime() {
1386 // better than nothing, but not much
1387 return elapsedTime();
1388 }
1389
1390 jlong os::javaTimeMillis() {
1391 timeval time;
1392 int status = gettimeofday(&time, NULL);
1393 assert(status != -1, "linux error");
1394 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1395 }
1396
1397 #ifndef CLOCK_MONOTONIC
1398 #define CLOCK_MONOTONIC (1)
1399 #endif
1400
1401 void os::Linux::clock_init() {
1402 // we do dlopen's in this particular order due to bug in linux
1403 // dynamical loader (see 6348968) leading to crash on exit
1404 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1405 if (handle == NULL) {
1406 handle = dlopen("librt.so", RTLD_LAZY);
1407 }
1408
1409 if (handle) {
1410 int (*clock_getres_func)(clockid_t, struct timespec*) =
1411 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1412 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1413 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1414 if (clock_getres_func && clock_gettime_func) {
1415 // See if monotonic clock is supported by the kernel. Note that some
1416 // early implementations simply return kernel jiffies (updated every
1417 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1418 // for nano time (though the monotonic property is still nice to have).
1419 // It's fixed in newer kernels, however clock_getres() still returns
1420 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1421 // resolution for now. Hopefully as people move to new kernels, this
1422 // won't be a problem.
1423 struct timespec res;
1424 struct timespec tp;
1425 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1426 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1427 // yes, monotonic clock is supported
1428 _clock_gettime = clock_gettime_func;
1429 } else {
1430 // close librt if there is no monotonic clock
1431 dlclose(handle);
1432 }
1433 }
1434 }
1435 }
1436
1437 #ifndef SYS_clock_getres
1438
1439 #if defined(IA32) || defined(AMD64)
1440 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1441 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1442 #else
1443 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1444 #define sys_clock_getres(x,y) -1
1445 #endif
1446
1447 #else
1448 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1449 #endif
1450
1451 void os::Linux::fast_thread_clock_init() {
1452 if (!UseLinuxPosixThreadCPUClocks) {
1453 return;
1454 }
1455 clockid_t clockid;
1456 struct timespec tp;
1457 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1458 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1459
1460 // Switch to using fast clocks for thread cpu time if
1461 // the sys_clock_getres() returns 0 error code.
1462 // Note, that some kernels may support the current thread
1463 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1464 // returned by the pthread_getcpuclockid().
1465 // If the fast Posix clocks are supported then the sys_clock_getres()
1466 // must return at least tp.tv_sec == 0 which means a resolution
1467 // better than 1 sec. This is extra check for reliability.
1468
1469 if(pthread_getcpuclockid_func &&
1470 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1471 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1472
1473 _supports_fast_thread_cpu_time = true;
1474 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1475 }
1476 }
1477
1478 jlong os::javaTimeNanos() {
1479 if (Linux::supports_monotonic_clock()) {
1480 struct timespec tp;
1481 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1482 assert(status == 0, "gettime error");
1483 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1484 return result;
1485 } else {
1486 timeval time;
1487 int status = gettimeofday(&time, NULL);
1488 assert(status != -1, "linux error");
1489 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1490 return 1000 * usecs;
1491 }
1492 }
1493
1494 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1495 if (Linux::supports_monotonic_clock()) {
1496 info_ptr->max_value = ALL_64_BITS;
1497
1498 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1499 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1500 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1501 } else {
1502 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1503 info_ptr->max_value = ALL_64_BITS;
1504
1505 // gettimeofday is a real time clock so it skips
1506 info_ptr->may_skip_backward = true;
1507 info_ptr->may_skip_forward = true;
1508 }
1509
1510 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1511 }
1512
1513 // Return the real, user, and system times in seconds from an
1514 // arbitrary fixed point in the past.
1515 bool os::getTimesSecs(double* process_real_time,
1516 double* process_user_time,
1517 double* process_system_time) {
1518 struct tms ticks;
1519 clock_t real_ticks = times(&ticks);
1520
1521 if (real_ticks == (clock_t) (-1)) {
1522 return false;
1523 } else {
1524 double ticks_per_second = (double) clock_tics_per_sec;
1525 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1526 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1527 *process_real_time = ((double) real_ticks) / ticks_per_second;
1528
1529 return true;
1530 }
1531 }
1532
1533
1534 char * os::local_time_string(char *buf, size_t buflen) {
1535 struct tm t;
1536 time_t long_time;
1537 time(&long_time);
1538 localtime_r(&long_time, &t);
1539 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1540 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1541 t.tm_hour, t.tm_min, t.tm_sec);
1542 return buf;
1543 }
1544
1545 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1546 return localtime_r(clock, res);
1547 }
1548
1549 ////////////////////////////////////////////////////////////////////////////////
1550 // runtime exit support
1551
1552 // Note: os::shutdown() might be called very early during initialization, or
1553 // called from signal handler. Before adding something to os::shutdown(), make
1554 // sure it is async-safe and can handle partially initialized VM.
1555 void os::shutdown() {
1556
1557 // allow PerfMemory to attempt cleanup of any persistent resources
1558 perfMemory_exit();
1559
1560 // needs to remove object in file system
1561 AttachListener::abort();
1562
1563 // flush buffered output, finish log files
1564 ostream_abort();
1565
1566 // Check for abort hook
1567 abort_hook_t abort_hook = Arguments::abort_hook();
1568 if (abort_hook != NULL) {
1569 abort_hook();
1570 }
1571
1572 }
1573
1574 // Note: os::abort() might be called very early during initialization, or
1575 // called from signal handler. Before adding something to os::abort(), make
1576 // sure it is async-safe and can handle partially initialized VM.
1577 void os::abort(bool dump_core) {
1578 os::shutdown();
1579 if (dump_core) {
1580 #ifndef PRODUCT
1581 fdStream out(defaultStream::output_fd());
1582 out.print_raw("Current thread is ");
1583 char buf[16];
1584 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1585 out.print_raw_cr(buf);
1586 out.print_raw_cr("Dumping core ...");
1587 #endif
1588 ::abort(); // dump core
1589 }
1590
1591 ::exit(1);
1592 }
1593
1594 // Die immediately, no exit hook, no abort hook, no cleanup.
1595 void os::die() {
1596 // _exit() on LinuxThreads only kills current thread
1597 ::abort();
1598 }
1599
1600 // unused on linux for now.
1601 void os::set_error_file(const char *logfile) {}
1602
1603
1604 // This method is a copy of JDK's sysGetLastErrorString
1605 // from src/solaris/hpi/src/system_md.c
1606
1607 size_t os::lasterror(char *buf, size_t len) {
1608
1609 if (errno == 0) return 0;
1610
1611 const char *s = ::strerror(errno);
1612 size_t n = ::strlen(s);
1613 if (n >= len) {
1614 n = len - 1;
1615 }
1616 ::strncpy(buf, s, n);
1617 buf[n] = '\0';
1618 return n;
1619 }
1620
1621 intx os::current_thread_id() { return (intx)pthread_self(); }
1622 int os::current_process_id() {
1623
1624 // Under the old linux thread library, linux gives each thread
1625 // its own process id. Because of this each thread will return
1626 // a different pid if this method were to return the result
1627 // of getpid(2). Linux provides no api that returns the pid
1628 // of the launcher thread for the vm. This implementation
1629 // returns a unique pid, the pid of the launcher thread
1630 // that starts the vm 'process'.
1631
1632 // Under the NPTL, getpid() returns the same pid as the
1633 // launcher thread rather than a unique pid per thread.
1634 // Use gettid() if you want the old pre NPTL behaviour.
1635
1636 // if you are looking for the result of a call to getpid() that
1637 // returns a unique pid for the calling thread, then look at the
1638 // OSThread::thread_id() method in osThread_linux.hpp file
1639
1640 return (int)(_initial_pid ? _initial_pid : getpid());
1641 }
1642
1643 // DLL functions
1644
1645 const char* os::dll_file_extension() { return ".so"; }
1646
1647 // This must be hard coded because it's the system's temporary
1648 // directory not the java application's temp directory, ala java.io.tmpdir.
1649 const char* os::get_temp_directory() { return "/tmp"; }
1650
1651 static bool file_exists(const char* filename) {
1652 struct stat statbuf;
1653 if (filename == NULL || strlen(filename) == 0) {
1654 return false;
1655 }
1656 return os::stat(filename, &statbuf) == 0;
1657 }
1658
1659 void os::dll_build_name(char* buffer, size_t buflen,
1660 const char* pname, const char* fname) {
1661 // Copied from libhpi
1662 const size_t pnamelen = pname ? strlen(pname) : 0;
1663
1664 // Quietly truncate on buffer overflow. Should be an error.
1665 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1666 *buffer = '\0';
1667 return;
1668 }
1669
1670 if (pnamelen == 0) {
1671 snprintf(buffer, buflen, "lib%s.so", fname);
1672 } else if (strchr(pname, *os::path_separator()) != NULL) {
1673 int n;
1674 char** pelements = split_path(pname, &n);
1675 for (int i = 0 ; i < n ; i++) {
1676 // Really shouldn't be NULL, but check can't hurt
1677 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1678 continue; // skip the empty path values
1679 }
1680 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1681 if (file_exists(buffer)) {
1682 break;
1683 }
1684 }
1685 // release the storage
1686 for (int i = 0 ; i < n ; i++) {
1687 if (pelements[i] != NULL) {
1688 FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal);
1689 }
1690 }
1691 if (pelements != NULL) {
1692 FREE_C_HEAP_ARRAY(char*, pelements, mtInternal);
1693 }
1694 } else {
1695 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1696 }
1697 }
1698
1699 const char* os::get_current_directory(char *buf, int buflen) {
1700 return getcwd(buf, buflen);
1701 }
1702
1703 // check if addr is inside libjvm[_g].so
1704 bool os::address_is_in_vm(address addr) {
1705 static address libjvm_base_addr;
1706 Dl_info dlinfo;
1707
1708 if (libjvm_base_addr == NULL) {
1709 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
1710 libjvm_base_addr = (address)dlinfo.dli_fbase;
1711 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1712 }
1713
1714 if (dladdr((void *)addr, &dlinfo)) {
1715 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1716 }
1717
1718 return false;
1719 }
1720
1721 bool os::dll_address_to_function_name(address addr, char *buf,
1722 int buflen, int *offset) {
1723 Dl_info dlinfo;
1724
1725 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
1726 if (buf != NULL) {
1727 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1728 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1729 }
1730 }
1731 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1732 return true;
1733 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) {
1734 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1735 buf, buflen, offset, dlinfo.dli_fname)) {
1736 return true;
1737 }
1738 }
1739
1740 if (buf != NULL) buf[0] = '\0';
1741 if (offset != NULL) *offset = -1;
1742 return false;
1743 }
1744
1745 struct _address_to_library_name {
1746 address addr; // input : memory address
1747 size_t buflen; // size of fname
1748 char* fname; // output: library name
1749 address base; // library base addr
1750 };
1751
1752 static int address_to_library_name_callback(struct dl_phdr_info *info,
1753 size_t size, void *data) {
1754 int i;
1755 bool found = false;
1756 address libbase = NULL;
1757 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1758
1759 // iterate through all loadable segments
1760 for (i = 0; i < info->dlpi_phnum; i++) {
1761 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1762 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1763 // base address of a library is the lowest address of its loaded
1764 // segments.
1765 if (libbase == NULL || libbase > segbase) {
1766 libbase = segbase;
1767 }
1768 // see if 'addr' is within current segment
1769 if (segbase <= d->addr &&
1770 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1771 found = true;
1772 }
1773 }
1774 }
1775
1776 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1777 // so dll_address_to_library_name() can fall through to use dladdr() which
1778 // can figure out executable name from argv[0].
1779 if (found && info->dlpi_name && info->dlpi_name[0]) {
1780 d->base = libbase;
1781 if (d->fname) {
1782 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1783 }
1784 return 1;
1785 }
1786 return 0;
1787 }
1788
1789 bool os::dll_address_to_library_name(address addr, char* buf,
1790 int buflen, int* offset) {
1791 Dl_info dlinfo;
1792 struct _address_to_library_name data;
1793
1794 // There is a bug in old glibc dladdr() implementation that it could resolve
1795 // to wrong library name if the .so file has a base address != NULL. Here
1796 // we iterate through the program headers of all loaded libraries to find
1797 // out which library 'addr' really belongs to. This workaround can be
1798 // removed once the minimum requirement for glibc is moved to 2.3.x.
1799 data.addr = addr;
1800 data.fname = buf;
1801 data.buflen = buflen;
1802 data.base = NULL;
1803 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1804
1805 if (rslt) {
1806 // buf already contains library name
1807 if (offset) *offset = addr - data.base;
1808 return true;
1809 } else if (dladdr((void*)addr, &dlinfo)){
1810 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1811 if (offset) *offset = addr - (address)dlinfo.dli_fbase;
1812 return true;
1813 } else {
1814 if (buf) buf[0] = '\0';
1815 if (offset) *offset = -1;
1816 return false;
1817 }
1818 }
1819
1820 // Loads .dll/.so and
1821 // in case of error it checks if .dll/.so was built for the
1822 // same architecture as Hotspot is running on
1823
1824 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1825 {
1826 void * result= ::dlopen(filename, RTLD_LAZY);
1827 if (result != NULL) {
1828 // Successful loading
1829 return result;
1830 }
1831
1832 Elf32_Ehdr elf_head;
1833
1834 // Read system error message into ebuf
1835 // It may or may not be overwritten below
1836 ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1837 ebuf[ebuflen-1]='\0';
1838 int diag_msg_max_length=ebuflen-strlen(ebuf);
1839 char* diag_msg_buf=ebuf+strlen(ebuf);
1840
1841 if (diag_msg_max_length==0) {
1842 // No more space in ebuf for additional diagnostics message
1843 return NULL;
1844 }
1845
1846
1847 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1848
1849 if (file_descriptor < 0) {
1850 // Can't open library, report dlerror() message
1851 return NULL;
1852 }
1853
1854 bool failed_to_read_elf_head=
1855 (sizeof(elf_head)!=
1856 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1857
1858 ::close(file_descriptor);
1859 if (failed_to_read_elf_head) {
1860 // file i/o error - report dlerror() msg
1861 return NULL;
1862 }
1863
1864 typedef struct {
1865 Elf32_Half code; // Actual value as defined in elf.h
1866 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1867 char elf_class; // 32 or 64 bit
1868 char endianess; // MSB or LSB
1869 char* name; // String representation
1870 } arch_t;
1871
1872 #ifndef EM_486
1873 #define EM_486 6 /* Intel 80486 */
1874 #endif
1875
1876 static const arch_t arch_array[]={
1877 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1878 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1879 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1880 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1881 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1882 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1883 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1884 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1885 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1886 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1887 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1888 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1889 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1890 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1891 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1892 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1893 };
1894
1895 #if (defined IA32)
1896 static Elf32_Half running_arch_code=EM_386;
1897 #elif (defined AMD64)
1898 static Elf32_Half running_arch_code=EM_X86_64;
1899 #elif (defined IA64)
1900 static Elf32_Half running_arch_code=EM_IA_64;
1901 #elif (defined __sparc) && (defined _LP64)
1902 static Elf32_Half running_arch_code=EM_SPARCV9;
1903 #elif (defined __sparc) && (!defined _LP64)
1904 static Elf32_Half running_arch_code=EM_SPARC;
1905 #elif (defined __powerpc64__)
1906 static Elf32_Half running_arch_code=EM_PPC64;
1907 #elif (defined __powerpc__)
1908 static Elf32_Half running_arch_code=EM_PPC;
1909 #elif (defined ARM)
1910 static Elf32_Half running_arch_code=EM_ARM;
1911 #elif (defined S390)
1912 static Elf32_Half running_arch_code=EM_S390;
1913 #elif (defined ALPHA)
1914 static Elf32_Half running_arch_code=EM_ALPHA;
1915 #elif (defined MIPSEL)
1916 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1917 #elif (defined PARISC)
1918 static Elf32_Half running_arch_code=EM_PARISC;
1919 #elif (defined MIPS)
1920 static Elf32_Half running_arch_code=EM_MIPS;
1921 #elif (defined M68K)
1922 static Elf32_Half running_arch_code=EM_68K;
1923 #else
1924 #error Method os::dll_load requires that one of following is defined:\
1925 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1926 #endif
1927
1928 // Identify compatability class for VM's architecture and library's architecture
1929 // Obtain string descriptions for architectures
1930
1931 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1932 int running_arch_index=-1;
1933
1934 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1935 if (running_arch_code == arch_array[i].code) {
1936 running_arch_index = i;
1937 }
1938 if (lib_arch.code == arch_array[i].code) {
1939 lib_arch.compat_class = arch_array[i].compat_class;
1940 lib_arch.name = arch_array[i].name;
1941 }
1942 }
1943
1944 assert(running_arch_index != -1,
1945 "Didn't find running architecture code (running_arch_code) in arch_array");
1946 if (running_arch_index == -1) {
1947 // Even though running architecture detection failed
1948 // we may still continue with reporting dlerror() message
1949 return NULL;
1950 }
1951
1952 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1953 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1954 return NULL;
1955 }
1956
1957 #ifndef S390
1958 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1959 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1960 return NULL;
1961 }
1962 #endif // !S390
1963
1964 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1965 if ( lib_arch.name!=NULL ) {
1966 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1967 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1968 lib_arch.name, arch_array[running_arch_index].name);
1969 } else {
1970 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1971 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1972 lib_arch.code,
1973 arch_array[running_arch_index].name);
1974 }
1975 }
1976
1977 return NULL;
1978 }
1979
1980 /*
1981 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
1982 * chances are you might want to run the generated bits against glibc-2.0
1983 * libdl.so, so always use locking for any version of glibc.
1984 */
1985 void* os::dll_lookup(void* handle, const char* name) {
1986 pthread_mutex_lock(&dl_mutex);
1987 void* res = dlsym(handle, name);
1988 pthread_mutex_unlock(&dl_mutex);
1989 return res;
1990 }
1991
1992
1993 static bool _print_ascii_file(const char* filename, outputStream* st) {
1994 int fd = ::open(filename, O_RDONLY);
1995 if (fd == -1) {
1996 return false;
1997 }
1998
1999 char buf[32];
2000 int bytes;
2001 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2002 st->print_raw(buf, bytes);
2003 }
2004
2005 ::close(fd);
2006
2007 return true;
2008 }
2009
2010 void os::print_dll_info(outputStream *st) {
2011 st->print_cr("Dynamic libraries:");
2012
2013 char fname[32];
2014 pid_t pid = os::Linux::gettid();
2015
2016 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2017
2018 if (!_print_ascii_file(fname, st)) {
2019 st->print("Can not get library information for pid = %d\n", pid);
2020 }
2021 }
2022
2023 void os::print_os_info_brief(outputStream* st) {
2024 os::Linux::print_distro_info(st);
2025
2026 os::Posix::print_uname_info(st);
2027
2028 os::Linux::print_libversion_info(st);
2029
2030 }
2031
2032 void os::print_os_info(outputStream* st) {
2033 st->print("OS:");
2034
2035 os::Linux::print_distro_info(st);
2036
2037 os::Posix::print_uname_info(st);
2038
2039 // Print warning if unsafe chroot environment detected
2040 if (unsafe_chroot_detected) {
2041 st->print("WARNING!! ");
2042 st->print_cr(unstable_chroot_error);
2043 }
2044
2045 os::Linux::print_libversion_info(st);
2046
2047 os::Posix::print_rlimit_info(st);
2048
2049 os::Posix::print_load_average(st);
2050
2051 os::Linux::print_full_memory_info(st);
2052 }
2053
2054 // Try to identify popular distros.
2055 // Most Linux distributions have /etc/XXX-release file, which contains
2056 // the OS version string. Some have more than one /etc/XXX-release file
2057 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
2058 // so the order is important.
2059 void os::Linux::print_distro_info(outputStream* st) {
2060 if (!_print_ascii_file("/etc/mandrake-release", st) &&
2061 !_print_ascii_file("/etc/sun-release", st) &&
2062 !_print_ascii_file("/etc/redhat-release", st) &&
2063 !_print_ascii_file("/etc/SuSE-release", st) &&
2064 !_print_ascii_file("/etc/turbolinux-release", st) &&
2065 !_print_ascii_file("/etc/gentoo-release", st) &&
2066 !_print_ascii_file("/etc/debian_version", st) &&
2067 !_print_ascii_file("/etc/ltib-release", st) &&
2068 !_print_ascii_file("/etc/angstrom-version", st)) {
2069 st->print("Linux");
2070 }
2071 st->cr();
2072 }
2073
2074 void os::Linux::print_libversion_info(outputStream* st) {
2075 // libc, pthread
2076 st->print("libc:");
2077 st->print(os::Linux::glibc_version()); st->print(" ");
2078 st->print(os::Linux::libpthread_version()); st->print(" ");
2079 if (os::Linux::is_LinuxThreads()) {
2080 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2081 }
2082 st->cr();
2083 }
2084
2085 void os::Linux::print_full_memory_info(outputStream* st) {
2086 st->print("\n/proc/meminfo:\n");
2087 _print_ascii_file("/proc/meminfo", st);
2088 st->cr();
2089 }
2090
2091 void os::print_memory_info(outputStream* st) {
2092
2093 st->print("Memory:");
2094 st->print(" %dk page", os::vm_page_size()>>10);
2095
2096 // values in struct sysinfo are "unsigned long"
2097 struct sysinfo si;
2098 sysinfo(&si);
2099
2100 st->print(", physical " UINT64_FORMAT "k",
2101 os::physical_memory() >> 10);
2102 st->print("(" UINT64_FORMAT "k free)",
2103 os::available_memory() >> 10);
2104 st->print(", swap " UINT64_FORMAT "k",
2105 ((jlong)si.totalswap * si.mem_unit) >> 10);
2106 st->print("(" UINT64_FORMAT "k free)",
2107 ((jlong)si.freeswap * si.mem_unit) >> 10);
2108 st->cr();
2109 }
2110
2111 void os::pd_print_cpu_info(outputStream* st) {
2112 st->print("\n/proc/cpuinfo:\n");
2113 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2114 st->print(" <Not Available>");
2115 }
2116 st->cr();
2117 }
2118
2119 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
2120 // but they're the same for all the linux arch that we support
2121 // and they're the same for solaris but there's no common place to put this.
2122 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
2123 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
2124 "ILL_COPROC", "ILL_BADSTK" };
2125
2126 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
2127 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
2128 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
2129
2130 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
2131
2132 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
2133
2134 void os::print_siginfo(outputStream* st, void* siginfo) {
2135 st->print("siginfo:");
2136
2137 const int buflen = 100;
2138 char buf[buflen];
2139 siginfo_t *si = (siginfo_t*)siginfo;
2140 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
2141 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
2142 st->print("si_errno=%s", buf);
2143 } else {
2144 st->print("si_errno=%d", si->si_errno);
2145 }
2146 const int c = si->si_code;
2147 assert(c > 0, "unexpected si_code");
2148 switch (si->si_signo) {
2149 case SIGILL:
2150 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
2151 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2152 break;
2153 case SIGFPE:
2154 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
2155 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2156 break;
2157 case SIGSEGV:
2158 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2159 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2160 break;
2161 case SIGBUS:
2162 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2163 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2164 break;
2165 default:
2166 st->print(", si_code=%d", si->si_code);
2167 // no si_addr
2168 }
2169
2170 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2171 UseSharedSpaces) {
2172 FileMapInfo* mapinfo = FileMapInfo::current_info();
2173 if (mapinfo->is_in_shared_space(si->si_addr)) {
2174 st->print("\n\nError accessing class data sharing archive." \
2175 " Mapped file inaccessible during execution, " \
2176 " possible disk/network problem.");
2177 }
2178 }
2179 st->cr();
2180 }
2181
2182
2183 static void print_signal_handler(outputStream* st, int sig,
2184 char* buf, size_t buflen);
2185
2186 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2187 st->print_cr("Signal Handlers:");
2188 print_signal_handler(st, SIGSEGV, buf, buflen);
2189 print_signal_handler(st, SIGBUS , buf, buflen);
2190 print_signal_handler(st, SIGFPE , buf, buflen);
2191 print_signal_handler(st, SIGPIPE, buf, buflen);
2192 print_signal_handler(st, SIGXFSZ, buf, buflen);
2193 print_signal_handler(st, SIGILL , buf, buflen);
2194 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2195 print_signal_handler(st, SR_signum, buf, buflen);
2196 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2197 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2198 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2199 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2200 }
2201
2202 static char saved_jvm_path[MAXPATHLEN] = {0};
2203
2204 // Find the full path to the current module, libjvm.so or libjvm_g.so
2205 void os::jvm_path(char *buf, jint buflen) {
2206 // Error checking.
2207 if (buflen < MAXPATHLEN) {
2208 assert(false, "must use a large-enough buffer");
2209 buf[0] = '\0';
2210 return;
2211 }
2212 // Lazy resolve the path to current module.
2213 if (saved_jvm_path[0] != 0) {
2214 strcpy(buf, saved_jvm_path);
2215 return;
2216 }
2217
2218 char dli_fname[MAXPATHLEN];
2219 bool ret = dll_address_to_library_name(
2220 CAST_FROM_FN_PTR(address, os::jvm_path),
2221 dli_fname, sizeof(dli_fname), NULL);
2222 assert(ret != 0, "cannot locate libjvm");
2223 char *rp = realpath(dli_fname, buf);
2224 if (rp == NULL)
2225 return;
2226
2227 if (Arguments::created_by_gamma_launcher()) {
2228 // Support for the gamma launcher. Typical value for buf is
2229 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2230 // the right place in the string, then assume we are installed in a JDK and
2231 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2232 // up the path so it looks like libjvm.so is installed there (append a
2233 // fake suffix hotspot/libjvm.so).
2234 const char *p = buf + strlen(buf) - 1;
2235 for (int count = 0; p > buf && count < 5; ++count) {
2236 for (--p; p > buf && *p != '/'; --p)
2237 /* empty */ ;
2238 }
2239
2240 if (strncmp(p, "/jre/lib/", 9) != 0) {
2241 // Look for JAVA_HOME in the environment.
2242 char* java_home_var = ::getenv("JAVA_HOME");
2243 if (java_home_var != NULL && java_home_var[0] != 0) {
2244 char* jrelib_p;
2245 int len;
2246
2247 // Check the current module name "libjvm.so" or "libjvm_g.so".
2248 p = strrchr(buf, '/');
2249 assert(strstr(p, "/libjvm") == p, "invalid library name");
2250 p = strstr(p, "_g") ? "_g" : "";
2251
2252 rp = realpath(java_home_var, buf);
2253 if (rp == NULL)
2254 return;
2255
2256 // determine if this is a legacy image or modules image
2257 // modules image doesn't have "jre" subdirectory
2258 len = strlen(buf);
2259 jrelib_p = buf + len;
2260 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2261 if (0 != access(buf, F_OK)) {
2262 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2263 }
2264
2265 if (0 == access(buf, F_OK)) {
2266 // Use current module name "libjvm[_g].so" instead of
2267 // "libjvm"debug_only("_g")".so" since for fastdebug version
2268 // we should have "libjvm.so" but debug_only("_g") adds "_g"!
2269 len = strlen(buf);
2270 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p);
2271 } else {
2272 // Go back to path of .so
2273 rp = realpath(dli_fname, buf);
2274 if (rp == NULL)
2275 return;
2276 }
2277 }
2278 }
2279 }
2280
2281 strcpy(saved_jvm_path, buf);
2282 }
2283
2284 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2285 // no prefix required, not even "_"
2286 }
2287
2288 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2289 // no suffix required
2290 }
2291
2292 ////////////////////////////////////////////////////////////////////////////////
2293 // sun.misc.Signal support
2294
2295 static volatile jint sigint_count = 0;
2296
2297 static void
2298 UserHandler(int sig, void *siginfo, void *context) {
2299 // 4511530 - sem_post is serialized and handled by the manager thread. When
2300 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2301 // don't want to flood the manager thread with sem_post requests.
2302 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2303 return;
2304
2305 // Ctrl-C is pressed during error reporting, likely because the error
2306 // handler fails to abort. Let VM die immediately.
2307 if (sig == SIGINT && is_error_reported()) {
2308 os::die();
2309 }
2310
2311 os::signal_notify(sig);
2312 }
2313
2314 void* os::user_handler() {
2315 return CAST_FROM_FN_PTR(void*, UserHandler);
2316 }
2317
2318 extern "C" {
2319 typedef void (*sa_handler_t)(int);
2320 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2321 }
2322
2323 void* os::signal(int signal_number, void* handler) {
2324 struct sigaction sigAct, oldSigAct;
2325
2326 sigfillset(&(sigAct.sa_mask));
2327 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2328 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2329
2330 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2331 // -1 means registration failed
2332 return (void *)-1;
2333 }
2334
2335 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2336 }
2337
2338 void os::signal_raise(int signal_number) {
2339 ::raise(signal_number);
2340 }
2341
2342 /*
2343 * The following code is moved from os.cpp for making this
2344 * code platform specific, which it is by its very nature.
2345 */
2346
2347 // Will be modified when max signal is changed to be dynamic
2348 int os::sigexitnum_pd() {
2349 return NSIG;
2350 }
2351
2352 // a counter for each possible signal value
2353 static volatile jint pending_signals[NSIG+1] = { 0 };
2354
2355 // Linux(POSIX) specific hand shaking semaphore.
2356 static sem_t sig_sem;
2357
2358 void os::signal_init_pd() {
2359 // Initialize signal structures
2360 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2361
2362 // Initialize signal semaphore
2363 ::sem_init(&sig_sem, 0, 0);
2364 }
2365
2366 void os::signal_notify(int sig) {
2367 Atomic::inc(&pending_signals[sig]);
2368 ::sem_post(&sig_sem);
2369 }
2370
2371 static int check_pending_signals(bool wait) {
2372 Atomic::store(0, &sigint_count);
2373 for (;;) {
2374 for (int i = 0; i < NSIG + 1; i++) {
2375 jint n = pending_signals[i];
2376 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2377 return i;
2378 }
2379 }
2380 if (!wait) {
2381 return -1;
2382 }
2383 JavaThread *thread = JavaThread::current();
2384 ThreadBlockInVM tbivm(thread);
2385
2386 bool threadIsSuspended;
2387 do {
2388 thread->set_suspend_equivalent();
2389 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2390 ::sem_wait(&sig_sem);
2391
2392 // were we externally suspended while we were waiting?
2393 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2394 if (threadIsSuspended) {
2395 //
2396 // The semaphore has been incremented, but while we were waiting
2397 // another thread suspended us. We don't want to continue running
2398 // while suspended because that would surprise the thread that
2399 // suspended us.
2400 //
2401 ::sem_post(&sig_sem);
2402
2403 thread->java_suspend_self();
2404 }
2405 } while (threadIsSuspended);
2406 }
2407 }
2408
2409 int os::signal_lookup() {
2410 return check_pending_signals(false);
2411 }
2412
2413 int os::signal_wait() {
2414 return check_pending_signals(true);
2415 }
2416
2417 ////////////////////////////////////////////////////////////////////////////////
2418 // Virtual Memory
2419
2420 int os::vm_page_size() {
2421 // Seems redundant as all get out
2422 assert(os::Linux::page_size() != -1, "must call os::init");
2423 return os::Linux::page_size();
2424 }
2425
2426 // Solaris allocates memory by pages.
2427 int os::vm_allocation_granularity() {
2428 assert(os::Linux::page_size() != -1, "must call os::init");
2429 return os::Linux::page_size();
2430 }
2431
2432 // Rationale behind this function:
2433 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2434 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2435 // samples for JITted code. Here we create private executable mapping over the code cache
2436 // and then we can use standard (well, almost, as mapping can change) way to provide
2437 // info for the reporting script by storing timestamp and location of symbol
2438 void linux_wrap_code(char* base, size_t size) {
2439 static volatile jint cnt = 0;
2440
2441 if (!UseOprofile) {
2442 return;
2443 }
2444
2445 char buf[PATH_MAX+1];
2446 int num = Atomic::add(1, &cnt);
2447
2448 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2449 os::get_temp_directory(), os::current_process_id(), num);
2450 unlink(buf);
2451
2452 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2453
2454 if (fd != -1) {
2455 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2456 if (rv != (off_t)-1) {
2457 if (::write(fd, "", 1) == 1) {
2458 mmap(base, size,
2459 PROT_READ|PROT_WRITE|PROT_EXEC,
2460 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2461 }
2462 }
2463 ::close(fd);
2464 unlink(buf);
2465 }
2466 }
2467
2468 // NOTE: Linux kernel does not really reserve the pages for us.
2469 // All it does is to check if there are enough free pages
2470 // left at the time of mmap(). This could be a potential
2471 // problem.
2472 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2473 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2474 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2475 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2476 if (res != (uintptr_t) MAP_FAILED) {
2477 if (UseNUMAInterleaving) {
2478 numa_make_global(addr, size);
2479 }
2480 return true;
2481 }
2482 return false;
2483 }
2484
2485 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2486 #ifndef MAP_HUGETLB
2487 #define MAP_HUGETLB 0x40000
2488 #endif
2489
2490 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2491 #ifndef MADV_HUGEPAGE
2492 #define MADV_HUGEPAGE 14
2493 #endif
2494
2495 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2496 bool exec) {
2497 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2498 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2499 uintptr_t res =
2500 (uintptr_t) ::mmap(addr, size, prot,
2501 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB,
2502 -1, 0);
2503 if (res != (uintptr_t) MAP_FAILED) {
2504 if (UseNUMAInterleaving) {
2505 numa_make_global(addr, size);
2506 }
2507 return true;
2508 }
2509 // Fall through and try to use small pages
2510 }
2511
2512 if (commit_memory(addr, size, exec)) {
2513 realign_memory(addr, size, alignment_hint);
2514 return true;
2515 }
2516 return false;
2517 }
2518
2519 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2520 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2521 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2522 // be supported or the memory may already be backed by huge pages.
2523 ::madvise(addr, bytes, MADV_HUGEPAGE);
2524 }
2525 }
2526
2527 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2528 // This method works by doing an mmap over an existing mmaping and effectively discarding
2529 // the existing pages. However it won't work for SHM-based large pages that cannot be
2530 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2531 // small pages on top of the SHM segment. This method always works for small pages, so we
2532 // allow that in any case.
2533 if (alignment_hint <= (size_t)os::vm_page_size() || !UseSHM) {
2534 commit_memory(addr, bytes, alignment_hint, false);
2535 }
2536 }
2537
2538 void os::numa_make_global(char *addr, size_t bytes) {
2539 Linux::numa_interleave_memory(addr, bytes);
2540 }
2541
2542 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2543 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2544 }
2545
2546 bool os::numa_topology_changed() { return false; }
2547
2548 size_t os::numa_get_groups_num() {
2549 int max_node = Linux::numa_max_node();
2550 return max_node > 0 ? max_node + 1 : 1;
2551 }
2552
2553 int os::numa_get_group_id() {
2554 int cpu_id = Linux::sched_getcpu();
2555 if (cpu_id != -1) {
2556 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2557 if (lgrp_id != -1) {
2558 return lgrp_id;
2559 }
2560 }
2561 return 0;
2562 }
2563
2564 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2565 for (size_t i = 0; i < size; i++) {
2566 ids[i] = i;
2567 }
2568 return size;
2569 }
2570
2571 bool os::get_page_info(char *start, page_info* info) {
2572 return false;
2573 }
2574
2575 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2576 return end;
2577 }
2578
2579
2580 int os::Linux::sched_getcpu_syscall(void) {
2581 unsigned int cpu;
2582 int retval = -1;
2583
2584 #if defined(IA32)
2585 # ifndef SYS_getcpu
2586 # define SYS_getcpu 318
2587 # endif
2588 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2589 #elif defined(AMD64)
2590 // Unfortunately we have to bring all these macros here from vsyscall.h
2591 // to be able to compile on old linuxes.
2592 # define __NR_vgetcpu 2
2593 # define VSYSCALL_START (-10UL << 20)
2594 # define VSYSCALL_SIZE 1024
2595 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2596 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2597 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2598 retval = vgetcpu(&cpu, NULL, NULL);
2599 #endif
2600
2601 return (retval == -1) ? retval : cpu;
2602 }
2603
2604 // Something to do with the numa-aware allocator needs these symbols
2605 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2606 extern "C" JNIEXPORT void numa_error(char *where) { }
2607 extern "C" JNIEXPORT int fork1() { return fork(); }
2608
2609
2610 // If we are running with libnuma version > 2, then we should
2611 // be trying to use symbols with versions 1.1
2612 // If we are running with earlier version, which did not have symbol versions,
2613 // we should use the base version.
2614 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2615 void *f = dlvsym(handle, name, "libnuma_1.1");
2616 if (f == NULL) {
2617 f = dlsym(handle, name);
2618 }
2619 return f;
2620 }
2621
2622 bool os::Linux::libnuma_init() {
2623 // sched_getcpu() should be in libc.
2624 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2625 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2626
2627 // If it's not, try a direct syscall.
2628 if (sched_getcpu() == -1)
2629 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2630
2631 if (sched_getcpu() != -1) { // Does it work?
2632 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2633 if (handle != NULL) {
2634 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2635 libnuma_dlsym(handle, "numa_node_to_cpus")));
2636 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2637 libnuma_dlsym(handle, "numa_max_node")));
2638 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2639 libnuma_dlsym(handle, "numa_available")));
2640 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2641 libnuma_dlsym(handle, "numa_tonode_memory")));
2642 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2643 libnuma_dlsym(handle, "numa_interleave_memory")));
2644
2645
2646 if (numa_available() != -1) {
2647 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2648 // Create a cpu -> node mapping
2649 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2650 rebuild_cpu_to_node_map();
2651 return true;
2652 }
2653 }
2654 }
2655 return false;
2656 }
2657
2658 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2659 // The table is later used in get_node_by_cpu().
2660 void os::Linux::rebuild_cpu_to_node_map() {
2661 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2662 // in libnuma (possible values are starting from 16,
2663 // and continuing up with every other power of 2, but less
2664 // than the maximum number of CPUs supported by kernel), and
2665 // is a subject to change (in libnuma version 2 the requirements
2666 // are more reasonable) we'll just hardcode the number they use
2667 // in the library.
2668 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2669
2670 size_t cpu_num = os::active_processor_count();
2671 size_t cpu_map_size = NCPUS / BitsPerCLong;
2672 size_t cpu_map_valid_size =
2673 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2674
2675 cpu_to_node()->clear();
2676 cpu_to_node()->at_grow(cpu_num - 1);
2677 size_t node_num = numa_get_groups_num();
2678
2679 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2680 for (size_t i = 0; i < node_num; i++) {
2681 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2682 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2683 if (cpu_map[j] != 0) {
2684 for (size_t k = 0; k < BitsPerCLong; k++) {
2685 if (cpu_map[j] & (1UL << k)) {
2686 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2687 }
2688 }
2689 }
2690 }
2691 }
2692 }
2693 FREE_C_HEAP_ARRAY(unsigned long, cpu_map, mtInternal);
2694 }
2695
2696 int os::Linux::get_node_by_cpu(int cpu_id) {
2697 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2698 return cpu_to_node()->at(cpu_id);
2699 }
2700 return -1;
2701 }
2702
2703 GrowableArray<int>* os::Linux::_cpu_to_node;
2704 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2705 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2706 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2707 os::Linux::numa_available_func_t os::Linux::_numa_available;
2708 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2709 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2710 unsigned long* os::Linux::_numa_all_nodes;
2711
2712 bool os::pd_uncommit_memory(char* addr, size_t size) {
2713 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2714 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2715 return res != (uintptr_t) MAP_FAILED;
2716 }
2717
2718 // Linux uses a growable mapping for the stack, and if the mapping for
2719 // the stack guard pages is not removed when we detach a thread the
2720 // stack cannot grow beyond the pages where the stack guard was
2721 // mapped. If at some point later in the process the stack expands to
2722 // that point, the Linux kernel cannot expand the stack any further
2723 // because the guard pages are in the way, and a segfault occurs.
2724 //
2725 // However, it's essential not to split the stack region by unmapping
2726 // a region (leaving a hole) that's already part of the stack mapping,
2727 // so if the stack mapping has already grown beyond the guard pages at
2728 // the time we create them, we have to truncate the stack mapping.
2729 // So, we need to know the extent of the stack mapping when
2730 // create_stack_guard_pages() is called.
2731
2732 // Find the bounds of the stack mapping. Return true for success.
2733 //
2734 // We only need this for stacks that are growable: at the time of
2735 // writing thread stacks don't use growable mappings (i.e. those
2736 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2737 // only applies to the main thread.
2738
2739 static
2740 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) {
2741
2742 char buf[128];
2743 int fd, sz;
2744
2745 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) {
2746 return false;
2747 }
2748
2749 const char kw[] = "[stack]";
2750 const int kwlen = sizeof(kw)-1;
2751
2752 // Address part of /proc/self/maps couldn't be more than 128 bytes
2753 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) {
2754 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) {
2755 // Extract addresses
2756 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
2757 uintptr_t sp = (uintptr_t) __builtin_frame_address(0);
2758 if (sp >= *bottom && sp <= *top) {
2759 ::close(fd);
2760 return true;
2761 }
2762 }
2763 }
2764 }
2765
2766 ::close(fd);
2767 return false;
2768 }
2769
2770
2771 // If the (growable) stack mapping already extends beyond the point
2772 // where we're going to put our guard pages, truncate the mapping at
2773 // that point by munmap()ping it. This ensures that when we later
2774 // munmap() the guard pages we don't leave a hole in the stack
2775 // mapping. This only affects the main/initial thread, but guard
2776 // against future OS changes
2777 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2778 uintptr_t stack_extent, stack_base;
2779 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2780 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2781 assert(os::Linux::is_initial_thread(),
2782 "growable stack in non-initial thread");
2783 if (stack_extent < (uintptr_t)addr)
2784 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent);
2785 }
2786
2787 return os::commit_memory(addr, size);
2788 }
2789
2790 // If this is a growable mapping, remove the guard pages entirely by
2791 // munmap()ping them. If not, just call uncommit_memory(). This only
2792 // affects the main/initial thread, but guard against future OS changes
2793 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2794 uintptr_t stack_extent, stack_base;
2795 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2796 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2797 assert(os::Linux::is_initial_thread(),
2798 "growable stack in non-initial thread");
2799
2800 return ::munmap(addr, size) == 0;
2801 }
2802
2803 return os::uncommit_memory(addr, size);
2804 }
2805
2806 static address _highest_vm_reserved_address = NULL;
2807
2808 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2809 // at 'requested_addr'. If there are existing memory mappings at the same
2810 // location, however, they will be overwritten. If 'fixed' is false,
2811 // 'requested_addr' is only treated as a hint, the return value may or
2812 // may not start from the requested address. Unlike Linux mmap(), this
2813 // function returns NULL to indicate failure.
2814 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2815 char * addr;
2816 int flags;
2817
2818 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2819 if (fixed) {
2820 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
2821 flags |= MAP_FIXED;
2822 }
2823
2824 // Map uncommitted pages PROT_READ and PROT_WRITE, change access
2825 // to PROT_EXEC if executable when we commit the page.
2826 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE,
2827 flags, -1, 0);
2828
2829 if (addr != MAP_FAILED) {
2830 // anon_mmap() should only get called during VM initialization,
2831 // don't need lock (actually we can skip locking even it can be called
2832 // from multiple threads, because _highest_vm_reserved_address is just a
2833 // hint about the upper limit of non-stack memory regions.)
2834 if ((address)addr + bytes > _highest_vm_reserved_address) {
2835 _highest_vm_reserved_address = (address)addr + bytes;
2836 }
2837 }
2838
2839 return addr == MAP_FAILED ? NULL : addr;
2840 }
2841
2842 // Don't update _highest_vm_reserved_address, because there might be memory
2843 // regions above addr + size. If so, releasing a memory region only creates
2844 // a hole in the address space, it doesn't help prevent heap-stack collision.
2845 //
2846 static int anon_munmap(char * addr, size_t size) {
2847 return ::munmap(addr, size) == 0;
2848 }
2849
2850 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
2851 size_t alignment_hint) {
2852 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2853 }
2854
2855 bool os::pd_release_memory(char* addr, size_t size) {
2856 return anon_munmap(addr, size);
2857 }
2858
2859 static address highest_vm_reserved_address() {
2860 return _highest_vm_reserved_address;
2861 }
2862
2863 static bool linux_mprotect(char* addr, size_t size, int prot) {
2864 // Linux wants the mprotect address argument to be page aligned.
2865 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
2866
2867 // According to SUSv3, mprotect() should only be used with mappings
2868 // established by mmap(), and mmap() always maps whole pages. Unaligned
2869 // 'addr' likely indicates problem in the VM (e.g. trying to change
2870 // protection of malloc'ed or statically allocated memory). Check the
2871 // caller if you hit this assert.
2872 assert(addr == bottom, "sanity check");
2873
2874 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
2875 return ::mprotect(bottom, size, prot) == 0;
2876 }
2877
2878 // Set protections specified
2879 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2880 bool is_committed) {
2881 unsigned int p = 0;
2882 switch (prot) {
2883 case MEM_PROT_NONE: p = PROT_NONE; break;
2884 case MEM_PROT_READ: p = PROT_READ; break;
2885 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
2886 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2887 default:
2888 ShouldNotReachHere();
2889 }
2890 // is_committed is unused.
2891 return linux_mprotect(addr, bytes, p);
2892 }
2893
2894 bool os::guard_memory(char* addr, size_t size) {
2895 return linux_mprotect(addr, size, PROT_NONE);
2896 }
2897
2898 bool os::unguard_memory(char* addr, size_t size) {
2899 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2900 }
2901
2902 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2903 bool result = false;
2904 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE,
2905 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
2906 -1, 0);
2907
2908 if (p != (void *) -1) {
2909 // We don't know if this really is a huge page or not.
2910 FILE *fp = fopen("/proc/self/maps", "r");
2911 if (fp) {
2912 while (!feof(fp)) {
2913 char chars[257];
2914 long x = 0;
2915 if (fgets(chars, sizeof(chars), fp)) {
2916 if (sscanf(chars, "%lx-%*x", &x) == 1
2917 && x == (long)p) {
2918 if (strstr (chars, "hugepage")) {
2919 result = true;
2920 break;
2921 }
2922 }
2923 }
2924 }
2925 fclose(fp);
2926 }
2927 munmap (p, page_size);
2928 if (result)
2929 return true;
2930 }
2931
2932 if (warn) {
2933 warning("HugeTLBFS is not supported by the operating system.");
2934 }
2935
2936 return result;
2937 }
2938
2939 /*
2940 * Set the coredump_filter bits to include largepages in core dump (bit 6)
2941 *
2942 * From the coredump_filter documentation:
2943 *
2944 * - (bit 0) anonymous private memory
2945 * - (bit 1) anonymous shared memory
2946 * - (bit 2) file-backed private memory
2947 * - (bit 3) file-backed shared memory
2948 * - (bit 4) ELF header pages in file-backed private memory areas (it is
2949 * effective only if the bit 2 is cleared)
2950 * - (bit 5) hugetlb private memory
2951 * - (bit 6) hugetlb shared memory
2952 */
2953 static void set_coredump_filter(void) {
2954 FILE *f;
2955 long cdm;
2956
2957 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
2958 return;
2959 }
2960
2961 if (fscanf(f, "%lx", &cdm) != 1) {
2962 fclose(f);
2963 return;
2964 }
2965
2966 rewind(f);
2967
2968 if ((cdm & LARGEPAGES_BIT) == 0) {
2969 cdm |= LARGEPAGES_BIT;
2970 fprintf(f, "%#lx", cdm);
2971 }
2972
2973 fclose(f);
2974 }
2975
2976 // Large page support
2977
2978 static size_t _large_page_size = 0;
2979
2980 void os::large_page_init() {
2981 if (!UseLargePages) {
2982 UseHugeTLBFS = false;
2983 UseSHM = false;
2984 return;
2985 }
2986
2987 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) {
2988 // If UseLargePages is specified on the command line try both methods,
2989 // if it's default, then try only HugeTLBFS.
2990 if (FLAG_IS_DEFAULT(UseLargePages)) {
2991 UseHugeTLBFS = true;
2992 } else {
2993 UseHugeTLBFS = UseSHM = true;
2994 }
2995 }
2996
2997 if (LargePageSizeInBytes) {
2998 _large_page_size = LargePageSizeInBytes;
2999 } else {
3000 // large_page_size on Linux is used to round up heap size. x86 uses either
3001 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3002 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3003 // page as large as 256M.
3004 //
3005 // Here we try to figure out page size by parsing /proc/meminfo and looking
3006 // for a line with the following format:
3007 // Hugepagesize: 2048 kB
3008 //
3009 // If we can't determine the value (e.g. /proc is not mounted, or the text
3010 // format has been changed), we'll use the largest page size supported by
3011 // the processor.
3012
3013 #ifndef ZERO
3014 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3015 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
3016 #endif // ZERO
3017
3018 FILE *fp = fopen("/proc/meminfo", "r");
3019 if (fp) {
3020 while (!feof(fp)) {
3021 int x = 0;
3022 char buf[16];
3023 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3024 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3025 _large_page_size = x * K;
3026 break;
3027 }
3028 } else {
3029 // skip to next line
3030 for (;;) {
3031 int ch = fgetc(fp);
3032 if (ch == EOF || ch == (int)'\n') break;
3033 }
3034 }
3035 }
3036 fclose(fp);
3037 }
3038 }
3039
3040 // print a warning if any large page related flag is specified on command line
3041 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3042
3043 const size_t default_page_size = (size_t)Linux::page_size();
3044 if (_large_page_size > default_page_size) {
3045 _page_sizes[0] = _large_page_size;
3046 _page_sizes[1] = default_page_size;
3047 _page_sizes[2] = 0;
3048 }
3049 UseHugeTLBFS = UseHugeTLBFS &&
3050 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size);
3051
3052 if (UseHugeTLBFS)
3053 UseSHM = false;
3054
3055 UseLargePages = UseHugeTLBFS || UseSHM;
3056
3057 set_coredump_filter();
3058 }
3059
3060 #ifndef SHM_HUGETLB
3061 #define SHM_HUGETLB 04000
3062 #endif
3063
3064 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
3065 // "exec" is passed in but not used. Creating the shared image for
3066 // the code cache doesn't have an SHM_X executable permission to check.
3067 assert(UseLargePages && UseSHM, "only for SHM large pages");
3068
3069 key_t key = IPC_PRIVATE;
3070 char *addr;
3071
3072 bool warn_on_failure = UseLargePages &&
3073 (!FLAG_IS_DEFAULT(UseLargePages) ||
3074 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3075 );
3076 char msg[128];
3077
3078 // Create a large shared memory region to attach to based on size.
3079 // Currently, size is the total size of the heap
3080 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3081 if (shmid == -1) {
3082 // Possible reasons for shmget failure:
3083 // 1. shmmax is too small for Java heap.
3084 // > check shmmax value: cat /proc/sys/kernel/shmmax
3085 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3086 // 2. not enough large page memory.
3087 // > check available large pages: cat /proc/meminfo
3088 // > increase amount of large pages:
3089 // echo new_value > /proc/sys/vm/nr_hugepages
3090 // Note 1: different Linux may use different name for this property,
3091 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3092 // Note 2: it's possible there's enough physical memory available but
3093 // they are so fragmented after a long run that they can't
3094 // coalesce into large pages. Try to reserve large pages when
3095 // the system is still "fresh".
3096 if (warn_on_failure) {
3097 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3098 warning(msg);
3099 }
3100 return NULL;
3101 }
3102
3103 // attach to the region
3104 addr = (char*)shmat(shmid, req_addr, 0);
3105 int err = errno;
3106
3107 // Remove shmid. If shmat() is successful, the actual shared memory segment
3108 // will be deleted when it's detached by shmdt() or when the process
3109 // terminates. If shmat() is not successful this will remove the shared
3110 // segment immediately.
3111 shmctl(shmid, IPC_RMID, NULL);
3112
3113 if ((intptr_t)addr == -1) {
3114 if (warn_on_failure) {
3115 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3116 warning(msg);
3117 }
3118 return NULL;
3119 }
3120
3121 if ((addr != NULL) && UseNUMAInterleaving) {
3122 numa_make_global(addr, bytes);
3123 }
3124
3125 return addr;
3126 }
3127
3128 bool os::release_memory_special(char* base, size_t bytes) {
3129 // detaching the SHM segment will also delete it, see reserve_memory_special()
3130 int rslt = shmdt(base);
3131 return rslt == 0;
3132 }
3133
3134 size_t os::large_page_size() {
3135 return _large_page_size;
3136 }
3137
3138 // HugeTLBFS allows application to commit large page memory on demand;
3139 // with SysV SHM the entire memory region must be allocated as shared
3140 // memory.
3141 bool os::can_commit_large_page_memory() {
3142 return UseHugeTLBFS;
3143 }
3144
3145 bool os::can_execute_large_page_memory() {
3146 return UseHugeTLBFS;
3147 }
3148
3149 // Reserve memory at an arbitrary address, only if that area is
3150 // available (and not reserved for something else).
3151
3152 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3153 const int max_tries = 10;
3154 char* base[max_tries];
3155 size_t size[max_tries];
3156 const size_t gap = 0x000000;
3157
3158 // Assert only that the size is a multiple of the page size, since
3159 // that's all that mmap requires, and since that's all we really know
3160 // about at this low abstraction level. If we need higher alignment,
3161 // we can either pass an alignment to this method or verify alignment
3162 // in one of the methods further up the call chain. See bug 5044738.
3163 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3164
3165 // Repeatedly allocate blocks until the block is allocated at the
3166 // right spot. Give up after max_tries. Note that reserve_memory() will
3167 // automatically update _highest_vm_reserved_address if the call is
3168 // successful. The variable tracks the highest memory address every reserved
3169 // by JVM. It is used to detect heap-stack collision if running with
3170 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3171 // space than needed, it could confuse the collision detecting code. To
3172 // solve the problem, save current _highest_vm_reserved_address and
3173 // calculate the correct value before return.
3174 address old_highest = _highest_vm_reserved_address;
3175
3176 // Linux mmap allows caller to pass an address as hint; give it a try first,
3177 // if kernel honors the hint then we can return immediately.
3178 char * addr = anon_mmap(requested_addr, bytes, false);
3179 if (addr == requested_addr) {
3180 return requested_addr;
3181 }
3182
3183 if (addr != NULL) {
3184 // mmap() is successful but it fails to reserve at the requested address
3185 anon_munmap(addr, bytes);
3186 }
3187
3188 int i;
3189 for (i = 0; i < max_tries; ++i) {
3190 base[i] = reserve_memory(bytes);
3191
3192 if (base[i] != NULL) {
3193 // Is this the block we wanted?
3194 if (base[i] == requested_addr) {
3195 size[i] = bytes;
3196 break;
3197 }
3198
3199 // Does this overlap the block we wanted? Give back the overlapped
3200 // parts and try again.
3201
3202 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3203 if (top_overlap >= 0 && top_overlap < bytes) {
3204 unmap_memory(base[i], top_overlap);
3205 base[i] += top_overlap;
3206 size[i] = bytes - top_overlap;
3207 } else {
3208 size_t bottom_overlap = base[i] + bytes - requested_addr;
3209 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3210 unmap_memory(requested_addr, bottom_overlap);
3211 size[i] = bytes - bottom_overlap;
3212 } else {
3213 size[i] = bytes;
3214 }
3215 }
3216 }
3217 }
3218
3219 // Give back the unused reserved pieces.
3220
3221 for (int j = 0; j < i; ++j) {
3222 if (base[j] != NULL) {
3223 unmap_memory(base[j], size[j]);
3224 }
3225 }
3226
3227 if (i < max_tries) {
3228 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3229 return requested_addr;
3230 } else {
3231 _highest_vm_reserved_address = old_highest;
3232 return NULL;
3233 }
3234 }
3235
3236 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3237 return ::read(fd, buf, nBytes);
3238 }
3239
3240 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
3241 // Solaris uses poll(), linux uses park().
3242 // Poll() is likely a better choice, assuming that Thread.interrupt()
3243 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
3244 // SIGSEGV, see 4355769.
3245
3246 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
3247 assert(thread == Thread::current(), "thread consistency check");
3248
3249 ParkEvent * const slp = thread->_SleepEvent ;
3250 slp->reset() ;
3251 OrderAccess::fence() ;
3252
3253 if (interruptible) {
3254 jlong prevtime = javaTimeNanos();
3255
3256 for (;;) {
3257 if (os::is_interrupted(thread, true)) {
3258 return OS_INTRPT;
3259 }
3260
3261 jlong newtime = javaTimeNanos();
3262
3263 if (newtime - prevtime < 0) {
3264 // time moving backwards, should only happen if no monotonic clock
3265 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3266 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3267 } else {
3268 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3269 }
3270
3271 if(millis <= 0) {
3272 return OS_OK;
3273 }
3274
3275 prevtime = newtime;
3276
3277 {
3278 assert(thread->is_Java_thread(), "sanity check");
3279 JavaThread *jt = (JavaThread *) thread;
3280 ThreadBlockInVM tbivm(jt);
3281 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
3282
3283 jt->set_suspend_equivalent();
3284 // cleared by handle_special_suspend_equivalent_condition() or
3285 // java_suspend_self() via check_and_wait_while_suspended()
3286
3287 slp->park(millis);
3288
3289 // were we externally suspended while we were waiting?
3290 jt->check_and_wait_while_suspended();
3291 }
3292 }
3293 } else {
3294 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
3295 jlong prevtime = javaTimeNanos();
3296
3297 for (;;) {
3298 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
3299 // the 1st iteration ...
3300 jlong newtime = javaTimeNanos();
3301
3302 if (newtime - prevtime < 0) {
3303 // time moving backwards, should only happen if no monotonic clock
3304 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3305 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3306 } else {
3307 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3308 }
3309
3310 if(millis <= 0) break ;
3311
3312 prevtime = newtime;
3313 slp->park(millis);
3314 }
3315 return OS_OK ;
3316 }
3317 }
3318
3319 int os::naked_sleep() {
3320 // %% make the sleep time an integer flag. for now use 1 millisec.
3321 return os::sleep(Thread::current(), 1, false);
3322 }
3323
3324 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3325 void os::infinite_sleep() {
3326 while (true) { // sleep forever ...
3327 ::sleep(100); // ... 100 seconds at a time
3328 }
3329 }
3330
3331 // Used to convert frequent JVM_Yield() to nops
3332 bool os::dont_yield() {
3333 return DontYieldALot;
3334 }
3335
3336 void os::yield() {
3337 sched_yield();
3338 }
3339
3340 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3341
3342 void os::yield_all(int attempts) {
3343 // Yields to all threads, including threads with lower priorities
3344 // Threads on Linux are all with same priority. The Solaris style
3345 // os::yield_all() with nanosleep(1ms) is not necessary.
3346 sched_yield();
3347 }
3348
3349 // Called from the tight loops to possibly influence time-sharing heuristics
3350 void os::loop_breaker(int attempts) {
3351 os::yield_all(attempts);
3352 }
3353
3354 ////////////////////////////////////////////////////////////////////////////////
3355 // thread priority support
3356
3357 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3358 // only supports dynamic priority, static priority must be zero. For real-time
3359 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3360 // However, for large multi-threaded applications, SCHED_RR is not only slower
3361 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3362 // of 5 runs - Sep 2005).
3363 //
3364 // The following code actually changes the niceness of kernel-thread/LWP. It
3365 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3366 // not the entire user process, and user level threads are 1:1 mapped to kernel
3367 // threads. It has always been the case, but could change in the future. For
3368 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3369 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3370
3371 int os::java_to_os_priority[CriticalPriority + 1] = {
3372 19, // 0 Entry should never be used
3373
3374 4, // 1 MinPriority
3375 3, // 2
3376 2, // 3
3377
3378 1, // 4
3379 0, // 5 NormPriority
3380 -1, // 6
3381
3382 -2, // 7
3383 -3, // 8
3384 -4, // 9 NearMaxPriority
3385
3386 -5, // 10 MaxPriority
3387
3388 -5 // 11 CriticalPriority
3389 };
3390
3391 static int prio_init() {
3392 if (ThreadPriorityPolicy == 1) {
3393 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3394 // if effective uid is not root. Perhaps, a more elegant way of doing
3395 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3396 if (geteuid() != 0) {
3397 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3398 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3399 }
3400 ThreadPriorityPolicy = 0;
3401 }
3402 }
3403 if (UseCriticalJavaThreadPriority) {
3404 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
3405 }
3406 return 0;
3407 }
3408
3409 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3410 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3411
3412 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3413 return (ret == 0) ? OS_OK : OS_ERR;
3414 }
3415
3416 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3417 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3418 *priority_ptr = java_to_os_priority[NormPriority];
3419 return OS_OK;
3420 }
3421
3422 errno = 0;
3423 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3424 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3425 }
3426
3427 // Hint to the underlying OS that a task switch would not be good.
3428 // Void return because it's a hint and can fail.
3429 void os::hint_no_preempt() {}
3430
3431 ////////////////////////////////////////////////////////////////////////////////
3432 // suspend/resume support
3433
3434 // the low-level signal-based suspend/resume support is a remnant from the
3435 // old VM-suspension that used to be for java-suspension, safepoints etc,
3436 // within hotspot. Now there is a single use-case for this:
3437 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3438 // that runs in the watcher thread.
3439 // The remaining code is greatly simplified from the more general suspension
3440 // code that used to be used.
3441 //
3442 // The protocol is quite simple:
3443 // - suspend:
3444 // - sends a signal to the target thread
3445 // - polls the suspend state of the osthread using a yield loop
3446 // - target thread signal handler (SR_handler) sets suspend state
3447 // and blocks in sigsuspend until continued
3448 // - resume:
3449 // - sets target osthread state to continue
3450 // - sends signal to end the sigsuspend loop in the SR_handler
3451 //
3452 // Note that the SR_lock plays no role in this suspend/resume protocol.
3453 //
3454
3455 static void resume_clear_context(OSThread *osthread) {
3456 osthread->set_ucontext(NULL);
3457 osthread->set_siginfo(NULL);
3458
3459 // notify the suspend action is completed, we have now resumed
3460 osthread->sr.clear_suspended();
3461 }
3462
3463 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3464 osthread->set_ucontext(context);
3465 osthread->set_siginfo(siginfo);
3466 }
3467
3468 //
3469 // Handler function invoked when a thread's execution is suspended or
3470 // resumed. We have to be careful that only async-safe functions are
3471 // called here (Note: most pthread functions are not async safe and
3472 // should be avoided.)
3473 //
3474 // Note: sigwait() is a more natural fit than sigsuspend() from an
3475 // interface point of view, but sigwait() prevents the signal hander
3476 // from being run. libpthread would get very confused by not having
3477 // its signal handlers run and prevents sigwait()'s use with the
3478 // mutex granting granting signal.
3479 //
3480 // Currently only ever called on the VMThread
3481 //
3482 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3483 // Save and restore errno to avoid confusing native code with EINTR
3484 // after sigsuspend.
3485 int old_errno = errno;
3486
3487 Thread* thread = Thread::current();
3488 OSThread* osthread = thread->osthread();
3489 assert(thread->is_VM_thread(), "Must be VMThread");
3490 // read current suspend action
3491 int action = osthread->sr.suspend_action();
3492 if (action == SR_SUSPEND) {
3493 suspend_save_context(osthread, siginfo, context);
3494
3495 // Notify the suspend action is about to be completed. do_suspend()
3496 // waits until SR_SUSPENDED is set and then returns. We will wait
3497 // here for a resume signal and that completes the suspend-other
3498 // action. do_suspend/do_resume is always called as a pair from
3499 // the same thread - so there are no races
3500
3501 // notify the caller
3502 osthread->sr.set_suspended();
3503
3504 sigset_t suspend_set; // signals for sigsuspend()
3505
3506 // get current set of blocked signals and unblock resume signal
3507 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3508 sigdelset(&suspend_set, SR_signum);
3509
3510 // wait here until we are resumed
3511 do {
3512 sigsuspend(&suspend_set);
3513 // ignore all returns until we get a resume signal
3514 } while (osthread->sr.suspend_action() != SR_CONTINUE);
3515
3516 resume_clear_context(osthread);
3517
3518 } else {
3519 assert(action == SR_CONTINUE, "unexpected sr action");
3520 // nothing special to do - just leave the handler
3521 }
3522
3523 errno = old_errno;
3524 }
3525
3526
3527 static int SR_initialize() {
3528 struct sigaction act;
3529 char *s;
3530 /* Get signal number to use for suspend/resume */
3531 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
3532 int sig = ::strtol(s, 0, 10);
3533 if (sig > 0 || sig < _NSIG) {
3534 SR_signum = sig;
3535 }
3536 }
3537
3538 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
3539 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
3540
3541 sigemptyset(&SR_sigset);
3542 sigaddset(&SR_sigset, SR_signum);
3543
3544 /* Set up signal handler for suspend/resume */
3545 act.sa_flags = SA_RESTART|SA_SIGINFO;
3546 act.sa_handler = (void (*)(int)) SR_handler;
3547
3548 // SR_signum is blocked by default.
3549 // 4528190 - We also need to block pthread restart signal (32 on all
3550 // supported Linux platforms). Note that LinuxThreads need to block
3551 // this signal for all threads to work properly. So we don't have
3552 // to use hard-coded signal number when setting up the mask.
3553 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
3554
3555 if (sigaction(SR_signum, &act, 0) == -1) {
3556 return -1;
3557 }
3558
3559 // Save signal flag
3560 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
3561 return 0;
3562 }
3563
3564 static int SR_finalize() {
3565 return 0;
3566 }
3567
3568
3569 // returns true on success and false on error - really an error is fatal
3570 // but this seems the normal response to library errors
3571 static bool do_suspend(OSThread* osthread) {
3572 // mark as suspended and send signal
3573 osthread->sr.set_suspend_action(SR_SUSPEND);
3574 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3575 assert_status(status == 0, status, "pthread_kill");
3576
3577 // check status and wait until notified of suspension
3578 if (status == 0) {
3579 for (int i = 0; !osthread->sr.is_suspended(); i++) {
3580 os::yield_all(i);
3581 }
3582 osthread->sr.set_suspend_action(SR_NONE);
3583 return true;
3584 }
3585 else {
3586 osthread->sr.set_suspend_action(SR_NONE);
3587 return false;
3588 }
3589 }
3590
3591 static void do_resume(OSThread* osthread) {
3592 assert(osthread->sr.is_suspended(), "thread should be suspended");
3593 osthread->sr.set_suspend_action(SR_CONTINUE);
3594
3595 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3596 assert_status(status == 0, status, "pthread_kill");
3597 // check status and wait unit notified of resumption
3598 if (status == 0) {
3599 for (int i = 0; osthread->sr.is_suspended(); i++) {
3600 os::yield_all(i);
3601 }
3602 }
3603 osthread->sr.set_suspend_action(SR_NONE);
3604 }
3605
3606 ////////////////////////////////////////////////////////////////////////////////
3607 // interrupt support
3608
3609 void os::interrupt(Thread* thread) {
3610 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3611 "possibility of dangling Thread pointer");
3612
3613 OSThread* osthread = thread->osthread();
3614
3615 if (!osthread->interrupted()) {
3616 osthread->set_interrupted(true);
3617 // More than one thread can get here with the same value of osthread,
3618 // resulting in multiple notifications. We do, however, want the store
3619 // to interrupted() to be visible to other threads before we execute unpark().
3620 OrderAccess::fence();
3621 ParkEvent * const slp = thread->_SleepEvent ;
3622 if (slp != NULL) slp->unpark() ;
3623 }
3624
3625 // For JSR166. Unpark even if interrupt status already was set
3626 if (thread->is_Java_thread())
3627 ((JavaThread*)thread)->parker()->unpark();
3628
3629 ParkEvent * ev = thread->_ParkEvent ;
3630 if (ev != NULL) ev->unpark() ;
3631
3632 }
3633
3634 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
3635 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3636 "possibility of dangling Thread pointer");
3637
3638 OSThread* osthread = thread->osthread();
3639
3640 bool interrupted = osthread->interrupted();
3641
3642 if (interrupted && clear_interrupted) {
3643 osthread->set_interrupted(false);
3644 // consider thread->_SleepEvent->reset() ... optional optimization
3645 }
3646
3647 return interrupted;
3648 }
3649
3650 ///////////////////////////////////////////////////////////////////////////////////
3651 // signal handling (except suspend/resume)
3652
3653 // This routine may be used by user applications as a "hook" to catch signals.
3654 // The user-defined signal handler must pass unrecognized signals to this
3655 // routine, and if it returns true (non-zero), then the signal handler must
3656 // return immediately. If the flag "abort_if_unrecognized" is true, then this
3657 // routine will never retun false (zero), but instead will execute a VM panic
3658 // routine kill the process.
3659 //
3660 // If this routine returns false, it is OK to call it again. This allows
3661 // the user-defined signal handler to perform checks either before or after
3662 // the VM performs its own checks. Naturally, the user code would be making
3663 // a serious error if it tried to handle an exception (such as a null check
3664 // or breakpoint) that the VM was generating for its own correct operation.
3665 //
3666 // This routine may recognize any of the following kinds of signals:
3667 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
3668 // It should be consulted by handlers for any of those signals.
3669 //
3670 // The caller of this routine must pass in the three arguments supplied
3671 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
3672 // field of the structure passed to sigaction(). This routine assumes that
3673 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
3674 //
3675 // Note that the VM will print warnings if it detects conflicting signal
3676 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
3677 //
3678 extern "C" JNIEXPORT int
3679 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
3680 void* ucontext, int abort_if_unrecognized);
3681
3682 void signalHandler(int sig, siginfo_t* info, void* uc) {
3683 assert(info != NULL && uc != NULL, "it must be old kernel");
3684 JVM_handle_linux_signal(sig, info, uc, true);
3685 }
3686
3687
3688 // This boolean allows users to forward their own non-matching signals
3689 // to JVM_handle_linux_signal, harmlessly.
3690 bool os::Linux::signal_handlers_are_installed = false;
3691
3692 // For signal-chaining
3693 struct sigaction os::Linux::sigact[MAXSIGNUM];
3694 unsigned int os::Linux::sigs = 0;
3695 bool os::Linux::libjsig_is_loaded = false;
3696 typedef struct sigaction *(*get_signal_t)(int);
3697 get_signal_t os::Linux::get_signal_action = NULL;
3698
3699 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
3700 struct sigaction *actp = NULL;
3701
3702 if (libjsig_is_loaded) {
3703 // Retrieve the old signal handler from libjsig
3704 actp = (*get_signal_action)(sig);
3705 }
3706 if (actp == NULL) {
3707 // Retrieve the preinstalled signal handler from jvm
3708 actp = get_preinstalled_handler(sig);
3709 }
3710
3711 return actp;
3712 }
3713
3714 static bool call_chained_handler(struct sigaction *actp, int sig,
3715 siginfo_t *siginfo, void *context) {
3716 // Call the old signal handler
3717 if (actp->sa_handler == SIG_DFL) {
3718 // It's more reasonable to let jvm treat it as an unexpected exception
3719 // instead of taking the default action.
3720 return false;
3721 } else if (actp->sa_handler != SIG_IGN) {
3722 if ((actp->sa_flags & SA_NODEFER) == 0) {
3723 // automaticlly block the signal
3724 sigaddset(&(actp->sa_mask), sig);
3725 }
3726
3727 sa_handler_t hand;
3728 sa_sigaction_t sa;
3729 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3730 // retrieve the chained handler
3731 if (siginfo_flag_set) {
3732 sa = actp->sa_sigaction;
3733 } else {
3734 hand = actp->sa_handler;
3735 }
3736
3737 if ((actp->sa_flags & SA_RESETHAND) != 0) {
3738 actp->sa_handler = SIG_DFL;
3739 }
3740
3741 // try to honor the signal mask
3742 sigset_t oset;
3743 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3744
3745 // call into the chained handler
3746 if (siginfo_flag_set) {
3747 (*sa)(sig, siginfo, context);
3748 } else {
3749 (*hand)(sig);
3750 }
3751
3752 // restore the signal mask
3753 pthread_sigmask(SIG_SETMASK, &oset, 0);
3754 }
3755 // Tell jvm's signal handler the signal is taken care of.
3756 return true;
3757 }
3758
3759 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3760 bool chained = false;
3761 // signal-chaining
3762 if (UseSignalChaining) {
3763 struct sigaction *actp = get_chained_signal_action(sig);
3764 if (actp != NULL) {
3765 chained = call_chained_handler(actp, sig, siginfo, context);
3766 }
3767 }
3768 return chained;
3769 }
3770
3771 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
3772 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
3773 return &sigact[sig];
3774 }
3775 return NULL;
3776 }
3777
3778 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3779 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3780 sigact[sig] = oldAct;
3781 sigs |= (unsigned int)1 << sig;
3782 }
3783
3784 // for diagnostic
3785 int os::Linux::sigflags[MAXSIGNUM];
3786
3787 int os::Linux::get_our_sigflags(int sig) {
3788 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3789 return sigflags[sig];
3790 }
3791
3792 void os::Linux::set_our_sigflags(int sig, int flags) {
3793 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3794 sigflags[sig] = flags;
3795 }
3796
3797 void os::Linux::set_signal_handler(int sig, bool set_installed) {
3798 // Check for overwrite.
3799 struct sigaction oldAct;
3800 sigaction(sig, (struct sigaction*)NULL, &oldAct);
3801
3802 void* oldhand = oldAct.sa_sigaction
3803 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3804 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3805 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3806 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3807 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3808 if (AllowUserSignalHandlers || !set_installed) {
3809 // Do not overwrite; user takes responsibility to forward to us.
3810 return;
3811 } else if (UseSignalChaining) {
3812 // save the old handler in jvm
3813 save_preinstalled_handler(sig, oldAct);
3814 // libjsig also interposes the sigaction() call below and saves the
3815 // old sigaction on it own.
3816 } else {
3817 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
3818 "%#lx for signal %d.", (long)oldhand, sig));
3819 }
3820 }
3821
3822 struct sigaction sigAct;
3823 sigfillset(&(sigAct.sa_mask));
3824 sigAct.sa_handler = SIG_DFL;
3825 if (!set_installed) {
3826 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3827 } else {
3828 sigAct.sa_sigaction = signalHandler;
3829 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3830 }
3831 // Save flags, which are set by ours
3832 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3833 sigflags[sig] = sigAct.sa_flags;
3834
3835 int ret = sigaction(sig, &sigAct, &oldAct);
3836 assert(ret == 0, "check");
3837
3838 void* oldhand2 = oldAct.sa_sigaction
3839 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3840 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3841 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3842 }
3843
3844 // install signal handlers for signals that HotSpot needs to
3845 // handle in order to support Java-level exception handling.
3846
3847 void os::Linux::install_signal_handlers() {
3848 if (!signal_handlers_are_installed) {
3849 signal_handlers_are_installed = true;
3850
3851 // signal-chaining
3852 typedef void (*signal_setting_t)();
3853 signal_setting_t begin_signal_setting = NULL;
3854 signal_setting_t end_signal_setting = NULL;
3855 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3856 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3857 if (begin_signal_setting != NULL) {
3858 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3859 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3860 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3861 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3862 libjsig_is_loaded = true;
3863 assert(UseSignalChaining, "should enable signal-chaining");
3864 }
3865 if (libjsig_is_loaded) {
3866 // Tell libjsig jvm is setting signal handlers
3867 (*begin_signal_setting)();
3868 }
3869
3870 set_signal_handler(SIGSEGV, true);
3871 set_signal_handler(SIGPIPE, true);
3872 set_signal_handler(SIGBUS, true);
3873 set_signal_handler(SIGILL, true);
3874 set_signal_handler(SIGFPE, true);
3875 set_signal_handler(SIGXFSZ, true);
3876
3877 if (libjsig_is_loaded) {
3878 // Tell libjsig jvm finishes setting signal handlers
3879 (*end_signal_setting)();
3880 }
3881
3882 // We don't activate signal checker if libjsig is in place, we trust ourselves
3883 // and if UserSignalHandler is installed all bets are off.
3884 // Log that signal checking is off only if -verbose:jni is specified.
3885 if (CheckJNICalls) {
3886 if (libjsig_is_loaded) {
3887 if (PrintJNIResolving) {
3888 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3889 }
3890 check_signals = false;
3891 }
3892 if (AllowUserSignalHandlers) {
3893 if (PrintJNIResolving) {
3894 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3895 }
3896 check_signals = false;
3897 }
3898 }
3899 }
3900 }
3901
3902 // This is the fastest way to get thread cpu time on Linux.
3903 // Returns cpu time (user+sys) for any thread, not only for current.
3904 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
3905 // It might work on 2.6.10+ with a special kernel/glibc patch.
3906 // For reference, please, see IEEE Std 1003.1-2004:
3907 // http://www.unix.org/single_unix_specification
3908
3909 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
3910 struct timespec tp;
3911 int rc = os::Linux::clock_gettime(clockid, &tp);
3912 assert(rc == 0, "clock_gettime is expected to return 0 code");
3913
3914 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
3915 }
3916
3917 /////
3918 // glibc on Linux platform uses non-documented flag
3919 // to indicate, that some special sort of signal
3920 // trampoline is used.
3921 // We will never set this flag, and we should
3922 // ignore this flag in our diagnostic
3923 #ifdef SIGNIFICANT_SIGNAL_MASK
3924 #undef SIGNIFICANT_SIGNAL_MASK
3925 #endif
3926 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3927
3928 static const char* get_signal_handler_name(address handler,
3929 char* buf, int buflen) {
3930 int offset;
3931 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3932 if (found) {
3933 // skip directory names
3934 const char *p1, *p2;
3935 p1 = buf;
3936 size_t len = strlen(os::file_separator());
3937 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3938 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3939 } else {
3940 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3941 }
3942 return buf;
3943 }
3944
3945 static void print_signal_handler(outputStream* st, int sig,
3946 char* buf, size_t buflen) {
3947 struct sigaction sa;
3948
3949 sigaction(sig, NULL, &sa);
3950
3951 // See comment for SIGNIFICANT_SIGNAL_MASK define
3952 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3953
3954 st->print("%s: ", os::exception_name(sig, buf, buflen));
3955
3956 address handler = (sa.sa_flags & SA_SIGINFO)
3957 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3958 : CAST_FROM_FN_PTR(address, sa.sa_handler);
3959
3960 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3961 st->print("SIG_DFL");
3962 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3963 st->print("SIG_IGN");
3964 } else {
3965 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3966 }
3967
3968 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
3969
3970 address rh = VMError::get_resetted_sighandler(sig);
3971 // May be, handler was resetted by VMError?
3972 if(rh != NULL) {
3973 handler = rh;
3974 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3975 }
3976
3977 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
3978
3979 // Check: is it our handler?
3980 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3981 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3982 // It is our signal handler
3983 // check for flags, reset system-used one!
3984 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
3985 st->print(
3986 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3987 os::Linux::get_our_sigflags(sig));
3988 }
3989 }
3990 st->cr();
3991 }
3992
3993
3994 #define DO_SIGNAL_CHECK(sig) \
3995 if (!sigismember(&check_signal_done, sig)) \
3996 os::Linux::check_signal_handler(sig)
3997
3998 // This method is a periodic task to check for misbehaving JNI applications
3999 // under CheckJNI, we can add any periodic checks here
4000
4001 void os::run_periodic_checks() {
4002
4003 if (check_signals == false) return;
4004
4005 // SEGV and BUS if overridden could potentially prevent
4006 // generation of hs*.log in the event of a crash, debugging
4007 // such a case can be very challenging, so we absolutely
4008 // check the following for a good measure:
4009 DO_SIGNAL_CHECK(SIGSEGV);
4010 DO_SIGNAL_CHECK(SIGILL);
4011 DO_SIGNAL_CHECK(SIGFPE);
4012 DO_SIGNAL_CHECK(SIGBUS);
4013 DO_SIGNAL_CHECK(SIGPIPE);
4014 DO_SIGNAL_CHECK(SIGXFSZ);
4015
4016
4017 // ReduceSignalUsage allows the user to override these handlers
4018 // see comments at the very top and jvm_solaris.h
4019 if (!ReduceSignalUsage) {
4020 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4021 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4022 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4023 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4024 }
4025
4026 DO_SIGNAL_CHECK(SR_signum);
4027 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4028 }
4029
4030 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4031
4032 static os_sigaction_t os_sigaction = NULL;
4033
4034 void os::Linux::check_signal_handler(int sig) {
4035 char buf[O_BUFLEN];
4036 address jvmHandler = NULL;
4037
4038
4039 struct sigaction act;
4040 if (os_sigaction == NULL) {
4041 // only trust the default sigaction, in case it has been interposed
4042 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4043 if (os_sigaction == NULL) return;
4044 }
4045
4046 os_sigaction(sig, (struct sigaction*)NULL, &act);
4047
4048
4049 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4050
4051 address thisHandler = (act.sa_flags & SA_SIGINFO)
4052 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4053 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4054
4055
4056 switch(sig) {
4057 case SIGSEGV:
4058 case SIGBUS:
4059 case SIGFPE:
4060 case SIGPIPE:
4061 case SIGILL:
4062 case SIGXFSZ:
4063 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4064 break;
4065
4066 case SHUTDOWN1_SIGNAL:
4067 case SHUTDOWN2_SIGNAL:
4068 case SHUTDOWN3_SIGNAL:
4069 case BREAK_SIGNAL:
4070 jvmHandler = (address)user_handler();
4071 break;
4072
4073 case INTERRUPT_SIGNAL:
4074 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4075 break;
4076
4077 default:
4078 if (sig == SR_signum) {
4079 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4080 } else {
4081 return;
4082 }
4083 break;
4084 }
4085
4086 if (thisHandler != jvmHandler) {
4087 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4088 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4089 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4090 // No need to check this sig any longer
4091 sigaddset(&check_signal_done, sig);
4092 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4093 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4094 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4095 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4096 // No need to check this sig any longer
4097 sigaddset(&check_signal_done, sig);
4098 }
4099
4100 // Dump all the signal
4101 if (sigismember(&check_signal_done, sig)) {
4102 print_signal_handlers(tty, buf, O_BUFLEN);
4103 }
4104 }
4105
4106 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4107
4108 extern bool signal_name(int signo, char* buf, size_t len);
4109
4110 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4111 if (0 < exception_code && exception_code <= SIGRTMAX) {
4112 // signal
4113 if (!signal_name(exception_code, buf, size)) {
4114 jio_snprintf(buf, size, "SIG%d", exception_code);
4115 }
4116 return buf;
4117 } else {
4118 return NULL;
4119 }
4120 }
4121
4122 // this is called _before_ the most of global arguments have been parsed
4123 void os::init(void) {
4124 char dummy; /* used to get a guess on initial stack address */
4125 // first_hrtime = gethrtime();
4126
4127 // With LinuxThreads the JavaMain thread pid (primordial thread)
4128 // is different than the pid of the java launcher thread.
4129 // So, on Linux, the launcher thread pid is passed to the VM
4130 // via the sun.java.launcher.pid property.
4131 // Use this property instead of getpid() if it was correctly passed.
4132 // See bug 6351349.
4133 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4134
4135 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4136
4137 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4138
4139 init_random(1234567);
4140
4141 ThreadCritical::initialize();
4142
4143 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4144 if (Linux::page_size() == -1) {
4145 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4146 strerror(errno)));
4147 }
4148 init_page_sizes((size_t) Linux::page_size());
4149
4150 Linux::initialize_system_info();
4151
4152 // main_thread points to the aboriginal thread
4153 Linux::_main_thread = pthread_self();
4154
4155 Linux::clock_init();
4156 initial_time_count = os::elapsed_counter();
4157 pthread_mutex_init(&dl_mutex, NULL);
4158 }
4159
4160 // To install functions for atexit system call
4161 extern "C" {
4162 static void perfMemory_exit_helper() {
4163 perfMemory_exit();
4164 }
4165 }
4166
4167 // this is called _after_ the global arguments have been parsed
4168 jint os::init_2(void)
4169 {
4170 Linux::fast_thread_clock_init();
4171
4172 // Allocate a single page and mark it as readable for safepoint polling
4173 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4174 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4175
4176 os::set_polling_page( polling_page );
4177
4178 #ifndef PRODUCT
4179 if(Verbose && PrintMiscellaneous)
4180 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4181 #endif
4182
4183 if (!UseMembar) {
4184 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4185 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page");
4186 os::set_memory_serialize_page( mem_serialize_page );
4187
4188 #ifndef PRODUCT
4189 if(Verbose && PrintMiscellaneous)
4190 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4191 #endif
4192 }
4193
4194 os::large_page_init();
4195
4196 // initialize suspend/resume support - must do this before signal_sets_init()
4197 if (SR_initialize() != 0) {
4198 perror("SR_initialize failed");
4199 return JNI_ERR;
4200 }
4201
4202 Linux::signal_sets_init();
4203 Linux::install_signal_handlers();
4204
4205 // Check minimum allowable stack size for thread creation and to initialize
4206 // the java system classes, including StackOverflowError - depends on page
4207 // size. Add a page for compiler2 recursion in main thread.
4208 // Add in 2*BytesPerWord times page size to account for VM stack during
4209 // class initialization depending on 32 or 64 bit VM.
4210 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4211 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+
4212 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size());
4213
4214 size_t threadStackSizeInBytes = ThreadStackSize * K;
4215 if (threadStackSizeInBytes != 0 &&
4216 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4217 tty->print_cr("\nThe stack size specified is too small, "
4218 "Specify at least %dk",
4219 os::Linux::min_stack_allowed/ K);
4220 return JNI_ERR;
4221 }
4222
4223 // Make the stack size a multiple of the page size so that
4224 // the yellow/red zones can be guarded.
4225 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4226 vm_page_size()));
4227
4228 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4229
4230 Linux::libpthread_init();
4231 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4232 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4233 Linux::glibc_version(), Linux::libpthread_version(),
4234 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4235 }
4236
4237 if (UseNUMA) {
4238 if (!Linux::libnuma_init()) {
4239 UseNUMA = false;
4240 } else {
4241 if ((Linux::numa_max_node() < 1)) {
4242 // There's only one node(they start from 0), disable NUMA.
4243 UseNUMA = false;
4244 }
4245 }
4246 // With SHM large pages we cannot uncommit a page, so there's not way
4247 // we can make the adaptive lgrp chunk resizing work. If the user specified
4248 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and
4249 // disable adaptive resizing.
4250 if (UseNUMA && UseLargePages && UseSHM) {
4251 if (!FLAG_IS_DEFAULT(UseNUMA)) {
4252 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) {
4253 UseLargePages = false;
4254 } else {
4255 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing");
4256 UseAdaptiveSizePolicy = false;
4257 UseAdaptiveNUMAChunkSizing = false;
4258 }
4259 } else {
4260 UseNUMA = false;
4261 }
4262 }
4263 if (!UseNUMA && ForceNUMA) {
4264 UseNUMA = true;
4265 }
4266 }
4267
4268 if (MaxFDLimit) {
4269 // set the number of file descriptors to max. print out error
4270 // if getrlimit/setrlimit fails but continue regardless.
4271 struct rlimit nbr_files;
4272 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4273 if (status != 0) {
4274 if (PrintMiscellaneous && (Verbose || WizardMode))
4275 perror("os::init_2 getrlimit failed");
4276 } else {
4277 nbr_files.rlim_cur = nbr_files.rlim_max;
4278 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4279 if (status != 0) {
4280 if (PrintMiscellaneous && (Verbose || WizardMode))
4281 perror("os::init_2 setrlimit failed");
4282 }
4283 }
4284 }
4285
4286 // Initialize lock used to serialize thread creation (see os::create_thread)
4287 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4288
4289 // at-exit methods are called in the reverse order of their registration.
4290 // atexit functions are called on return from main or as a result of a
4291 // call to exit(3C). There can be only 32 of these functions registered
4292 // and atexit() does not set errno.
4293
4294 if (PerfAllowAtExitRegistration) {
4295 // only register atexit functions if PerfAllowAtExitRegistration is set.
4296 // atexit functions can be delayed until process exit time, which
4297 // can be problematic for embedded VM situations. Embedded VMs should
4298 // call DestroyJavaVM() to assure that VM resources are released.
4299
4300 // note: perfMemory_exit_helper atexit function may be removed in
4301 // the future if the appropriate cleanup code can be added to the
4302 // VM_Exit VMOperation's doit method.
4303 if (atexit(perfMemory_exit_helper) != 0) {
4304 warning("os::init2 atexit(perfMemory_exit_helper) failed");
4305 }
4306 }
4307
4308 // initialize thread priority policy
4309 prio_init();
4310
4311 return JNI_OK;
4312 }
4313
4314 // this is called at the end of vm_initialization
4315 void os::init_3(void)
4316 {
4317 #ifdef JAVASE_EMBEDDED
4318 // Start the MemNotifyThread
4319 if (LowMemoryProtection) {
4320 MemNotifyThread::start();
4321 }
4322 return;
4323 #endif
4324 }
4325
4326 // Mark the polling page as unreadable
4327 void os::make_polling_page_unreadable(void) {
4328 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
4329 fatal("Could not disable polling page");
4330 };
4331
4332 // Mark the polling page as readable
4333 void os::make_polling_page_readable(void) {
4334 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4335 fatal("Could not enable polling page");
4336 }
4337 };
4338
4339 int os::active_processor_count() {
4340 // Linux doesn't yet have a (official) notion of processor sets,
4341 // so just return the number of online processors.
4342 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4343 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
4344 return online_cpus;
4345 }
4346
4347 #define MAXTHREADNAMESIZE 16
4348
4349 void os::set_native_thread_name(const char *name) {
4350 if (name != NULL) {
4351 // The maximum length is 16 (including the trailing \0), we copy
4352 // the first 15 chars into the buffer.
4353 char buf[MAXTHREADNAMESIZE];
4354 jio_snprintf(buf, sizeof(buf), "%s", name);
4355 pthread_setname_np(pthread_self(), buf);
4356 }
4357 }
4358
4359 // TODO: This is almost 100% copied from os_solaris.cpp,
4360 // it can and should be extracted into a shared method.
4361 static bool assign_distribution(uint* id_array,
4362 uint id_length,
4363 uint* distribution,
4364 uint distribution_length) {
4365 // Quick check to see if we won't succeed.
4366 if (id_length < distribution_length) {
4367 return false;
4368 }
4369 // Assign processor ids to the distribution.
4370 // Try to shuffle processors to distribute work across boards,
4371 // assuming 4 processors per board.
4372 const uint processors_per_board = ProcessDistributionStride;
4373 // Find the maximum processor id.
4374 uint max_id = 0;
4375 for (uint m = 0; m < id_length; m += 1) {
4376 max_id = MAX2(max_id, id_array[m]);
4377 }
4378 // The next id, to limit loops.
4379 const uint limit_id = max_id + 1;
4380 // Make up markers for available processors.
4381 bool* available_id = NEW_C_HEAP_ARRAY(bool, limit_id, mtInternal);
4382 for (uint c = 0; c < limit_id; c += 1) {
4383 available_id[c] = false;
4384 }
4385 for (uint a = 0; a < id_length; a += 1) {
4386 available_id[id_array[a]] = true;
4387 }
4388 // Step by "boards", then by "slot", copying to "assigned".
4389 // NEEDS_CLEANUP: The assignment of processors should be stateful,
4390 // remembering which processors have been assigned by
4391 // previous calls, etc., so as to distribute several
4392 // independent calls of this method. What we'd like is
4393 // It would be nice to have an API that let us ask
4394 // how many processes are bound to a processor,
4395 // but we don't have that, either.
4396 // In the short term, "board" is static so that
4397 // subsequent distributions don't all start at board 0.
4398 static uint board = 0;
4399 uint assigned = 0;
4400 // Until we've found enough processors ....
4401 while (assigned < distribution_length) {
4402 // ... find the next available processor in the board.
4403 for (uint slot = 0; slot < processors_per_board; slot += 1) {
4404 uint try_id = board * processors_per_board + slot;
4405 if ((try_id < limit_id) && (available_id[try_id] == true)) {
4406 distribution[assigned] = try_id;
4407 available_id[try_id] = false;
4408 assigned += 1;
4409 break;
4410 }
4411 }
4412 board += 1;
4413 if (board * processors_per_board + 0 >= limit_id) {
4414 board = 0;
4415 }
4416 }
4417 if (available_id != NULL) {
4418 FREE_C_HEAP_ARRAY(bool, available_id, mtInternal);
4419 }
4420 return true;
4421 }
4422
4423 bool os::distribute_processes(uint length, uint* distribution) {
4424
4425 cpu_set_t cpu_set;
4426
4427 int result = pthread_getaffinity_np(pthread_self(), sizeof(cpu_set_t), &cpu_set);
4428
4429 if (result == 0) {
4430
4431 uint cpu_ids_length;
4432 uint *cpu_ids;
4433 uint cpu_ids_found = 0;
4434
4435 cpu_ids_length = CPU_COUNT(&cpu_set);
4436
4437 cpu_ids = NEW_C_HEAP_ARRAY(uint, cpu_ids_length, mtInternal);
4438
4439 for (uint i = 0; i < CPU_SETSIZE && cpu_ids_found < cpu_ids_length; i++) {
4440 if (CPU_ISSET(i, &cpu_set)) {
4441 cpu_ids[cpu_ids_found] = i;
4442 cpu_ids_found++;
4443 }
4444 }
4445 bool result = assign_distribution(cpu_ids, cpu_ids_length, distribution, length);
4446
4447 FREE_C_HEAP_ARRAY(uint, cpu_ids, mtInternal);
4448
4449 return result;
4450 }
4451 return false;
4452 }
4453
4454 bool os::bind_to_processor(uint processor_id) {
4455 cpu_set_t cpu_set;
4456 CPU_ZERO(&cpu_set);
4457 CPU_SET(processor_id, &cpu_set);
4458 pthread_t current_thread = pthread_self();
4459 int result = pthread_setaffinity_np(current_thread, sizeof(cpu_set), &cpu_set);
4460 return result;
4461 }
4462
4463 ///
4464
4465 // Suspends the target using the signal mechanism and then grabs the PC before
4466 // resuming the target. Used by the flat-profiler only
4467 ExtendedPC os::get_thread_pc(Thread* thread) {
4468 // Make sure that it is called by the watcher for the VMThread
4469 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4470 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4471
4472 ExtendedPC epc;
4473
4474 OSThread* osthread = thread->osthread();
4475 if (do_suspend(osthread)) {
4476 if (osthread->ucontext() != NULL) {
4477 epc = os::Linux::ucontext_get_pc(osthread->ucontext());
4478 } else {
4479 // NULL context is unexpected, double-check this is the VMThread
4480 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4481 }
4482 do_resume(osthread);
4483 }
4484 // failure means pthread_kill failed for some reason - arguably this is
4485 // a fatal problem, but such problems are ignored elsewhere
4486
4487 return epc;
4488 }
4489
4490 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4491 {
4492 if (is_NPTL()) {
4493 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4494 } else {
4495 #ifndef IA64
4496 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4497 // word back to default 64bit precision if condvar is signaled. Java
4498 // wants 53bit precision. Save and restore current value.
4499 int fpu = get_fpu_control_word();
4500 #endif // IA64
4501 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4502 #ifndef IA64
4503 set_fpu_control_word(fpu);
4504 #endif // IA64
4505 return status;
4506 }
4507 }
4508
4509 ////////////////////////////////////////////////////////////////////////////////
4510 // debug support
4511
4512 static address same_page(address x, address y) {
4513 int page_bits = -os::vm_page_size();
4514 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
4515 return x;
4516 else if (x > y)
4517 return (address)(intptr_t(y) | ~page_bits) + 1;
4518 else
4519 return (address)(intptr_t(y) & page_bits);
4520 }
4521
4522 bool os::find(address addr, outputStream* st) {
4523 Dl_info dlinfo;
4524 memset(&dlinfo, 0, sizeof(dlinfo));
4525 if (dladdr(addr, &dlinfo)) {
4526 st->print(PTR_FORMAT ": ", addr);
4527 if (dlinfo.dli_sname != NULL) {
4528 st->print("%s+%#x", dlinfo.dli_sname,
4529 addr - (intptr_t)dlinfo.dli_saddr);
4530 } else if (dlinfo.dli_fname) {
4531 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4532 } else {
4533 st->print("<absolute address>");
4534 }
4535 if (dlinfo.dli_fname) {
4536 st->print(" in %s", dlinfo.dli_fname);
4537 }
4538 if (dlinfo.dli_fbase) {
4539 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4540 }
4541 st->cr();
4542
4543 if (Verbose) {
4544 // decode some bytes around the PC
4545 address begin = same_page(addr-40, addr);
4546 address end = same_page(addr+40, addr);
4547 address lowest = (address) dlinfo.dli_sname;
4548 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4549 if (begin < lowest) begin = lowest;
4550 Dl_info dlinfo2;
4551 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
4552 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
4553 end = (address) dlinfo2.dli_saddr;
4554 Disassembler::decode(begin, end, st);
4555 }
4556 return true;
4557 }
4558 return false;
4559 }
4560
4561 ////////////////////////////////////////////////////////////////////////////////
4562 // misc
4563
4564 // This does not do anything on Linux. This is basically a hook for being
4565 // able to use structured exception handling (thread-local exception filters)
4566 // on, e.g., Win32.
4567 void
4568 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
4569 JavaCallArguments* args, Thread* thread) {
4570 f(value, method, args, thread);
4571 }
4572
4573 void os::print_statistics() {
4574 }
4575
4576 int os::message_box(const char* title, const char* message) {
4577 int i;
4578 fdStream err(defaultStream::error_fd());
4579 for (i = 0; i < 78; i++) err.print_raw("=");
4580 err.cr();
4581 err.print_raw_cr(title);
4582 for (i = 0; i < 78; i++) err.print_raw("-");
4583 err.cr();
4584 err.print_raw_cr(message);
4585 for (i = 0; i < 78; i++) err.print_raw("=");
4586 err.cr();
4587
4588 char buf[16];
4589 // Prevent process from exiting upon "read error" without consuming all CPU
4590 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
4591
4592 return buf[0] == 'y' || buf[0] == 'Y';
4593 }
4594
4595 int os::stat(const char *path, struct stat *sbuf) {
4596 char pathbuf[MAX_PATH];
4597 if (strlen(path) > MAX_PATH - 1) {
4598 errno = ENAMETOOLONG;
4599 return -1;
4600 }
4601 os::native_path(strcpy(pathbuf, path));
4602 return ::stat(pathbuf, sbuf);
4603 }
4604
4605 bool os::check_heap(bool force) {
4606 return true;
4607 }
4608
4609 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
4610 return ::vsnprintf(buf, count, format, args);
4611 }
4612
4613 // Is a (classpath) directory empty?
4614 bool os::dir_is_empty(const char* path) {
4615 DIR *dir = NULL;
4616 struct dirent *ptr;
4617
4618 dir = opendir(path);
4619 if (dir == NULL) return true;
4620
4621 /* Scan the directory */
4622 bool result = true;
4623 char buf[sizeof(struct dirent) + MAX_PATH];
4624 while (result && (ptr = ::readdir(dir)) != NULL) {
4625 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
4626 result = false;
4627 }
4628 }
4629 closedir(dir);
4630 return result;
4631 }
4632
4633 // This code originates from JDK's sysOpen and open64_w
4634 // from src/solaris/hpi/src/system_md.c
4635
4636 #ifndef O_DELETE
4637 #define O_DELETE 0x10000
4638 #endif
4639
4640 // Open a file. Unlink the file immediately after open returns
4641 // if the specified oflag has the O_DELETE flag set.
4642 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
4643
4644 int os::open(const char *path, int oflag, int mode) {
4645
4646 if (strlen(path) > MAX_PATH - 1) {
4647 errno = ENAMETOOLONG;
4648 return -1;
4649 }
4650 int fd;
4651 int o_delete = (oflag & O_DELETE);
4652 oflag = oflag & ~O_DELETE;
4653
4654 fd = ::open64(path, oflag, mode);
4655 if (fd == -1) return -1;
4656
4657 //If the open succeeded, the file might still be a directory
4658 {
4659 struct stat64 buf64;
4660 int ret = ::fstat64(fd, &buf64);
4661 int st_mode = buf64.st_mode;
4662
4663 if (ret != -1) {
4664 if ((st_mode & S_IFMT) == S_IFDIR) {
4665 errno = EISDIR;
4666 ::close(fd);
4667 return -1;
4668 }
4669 } else {
4670 ::close(fd);
4671 return -1;
4672 }
4673 }
4674
4675 /*
4676 * All file descriptors that are opened in the JVM and not
4677 * specifically destined for a subprocess should have the
4678 * close-on-exec flag set. If we don't set it, then careless 3rd
4679 * party native code might fork and exec without closing all
4680 * appropriate file descriptors (e.g. as we do in closeDescriptors in
4681 * UNIXProcess.c), and this in turn might:
4682 *
4683 * - cause end-of-file to fail to be detected on some file
4684 * descriptors, resulting in mysterious hangs, or
4685 *
4686 * - might cause an fopen in the subprocess to fail on a system
4687 * suffering from bug 1085341.
4688 *
4689 * (Yes, the default setting of the close-on-exec flag is a Unix
4690 * design flaw)
4691 *
4692 * See:
4693 * 1085341: 32-bit stdio routines should support file descriptors >255
4694 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
4695 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
4696 */
4697 #ifdef FD_CLOEXEC
4698 {
4699 int flags = ::fcntl(fd, F_GETFD);
4700 if (flags != -1)
4701 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
4702 }
4703 #endif
4704
4705 if (o_delete != 0) {
4706 ::unlink(path);
4707 }
4708 return fd;
4709 }
4710
4711
4712 // create binary file, rewriting existing file if required
4713 int os::create_binary_file(const char* path, bool rewrite_existing) {
4714 int oflags = O_WRONLY | O_CREAT;
4715 if (!rewrite_existing) {
4716 oflags |= O_EXCL;
4717 }
4718 return ::open64(path, oflags, S_IREAD | S_IWRITE);
4719 }
4720
4721 // return current position of file pointer
4722 jlong os::current_file_offset(int fd) {
4723 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
4724 }
4725
4726 // move file pointer to the specified offset
4727 jlong os::seek_to_file_offset(int fd, jlong offset) {
4728 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
4729 }
4730
4731 // This code originates from JDK's sysAvailable
4732 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
4733
4734 int os::available(int fd, jlong *bytes) {
4735 jlong cur, end;
4736 int mode;
4737 struct stat64 buf64;
4738
4739 if (::fstat64(fd, &buf64) >= 0) {
4740 mode = buf64.st_mode;
4741 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
4742 /*
4743 * XXX: is the following call interruptible? If so, this might
4744 * need to go through the INTERRUPT_IO() wrapper as for other
4745 * blocking, interruptible calls in this file.
4746 */
4747 int n;
4748 if (::ioctl(fd, FIONREAD, &n) >= 0) {
4749 *bytes = n;
4750 return 1;
4751 }
4752 }
4753 }
4754 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
4755 return 0;
4756 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
4757 return 0;
4758 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
4759 return 0;
4760 }
4761 *bytes = end - cur;
4762 return 1;
4763 }
4764
4765 int os::socket_available(int fd, jint *pbytes) {
4766 // Linux doc says EINTR not returned, unlike Solaris
4767 int ret = ::ioctl(fd, FIONREAD, pbytes);
4768
4769 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
4770 // is expected to return 0 on failure and 1 on success to the jdk.
4771 return (ret < 0) ? 0 : 1;
4772 }
4773
4774 // Map a block of memory.
4775 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
4776 char *addr, size_t bytes, bool read_only,
4777 bool allow_exec) {
4778 int prot;
4779 int flags = MAP_PRIVATE;
4780
4781 if (read_only) {
4782 prot = PROT_READ;
4783 } else {
4784 prot = PROT_READ | PROT_WRITE;
4785 }
4786
4787 if (allow_exec) {
4788 prot |= PROT_EXEC;
4789 }
4790
4791 if (addr != NULL) {
4792 flags |= MAP_FIXED;
4793 }
4794
4795 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
4796 fd, file_offset);
4797 if (mapped_address == MAP_FAILED) {
4798 return NULL;
4799 }
4800 return mapped_address;
4801 }
4802
4803
4804 // Remap a block of memory.
4805 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
4806 char *addr, size_t bytes, bool read_only,
4807 bool allow_exec) {
4808 // same as map_memory() on this OS
4809 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4810 allow_exec);
4811 }
4812
4813
4814 // Unmap a block of memory.
4815 bool os::pd_unmap_memory(char* addr, size_t bytes) {
4816 return munmap(addr, bytes) == 0;
4817 }
4818
4819 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
4820
4821 static clockid_t thread_cpu_clockid(Thread* thread) {
4822 pthread_t tid = thread->osthread()->pthread_id();
4823 clockid_t clockid;
4824
4825 // Get thread clockid
4826 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
4827 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
4828 return clockid;
4829 }
4830
4831 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4832 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4833 // of a thread.
4834 //
4835 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4836 // the fast estimate available on the platform.
4837
4838 jlong os::current_thread_cpu_time() {
4839 if (os::Linux::supports_fast_thread_cpu_time()) {
4840 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4841 } else {
4842 // return user + sys since the cost is the same
4843 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
4844 }
4845 }
4846
4847 jlong os::thread_cpu_time(Thread* thread) {
4848 // consistent with what current_thread_cpu_time() returns
4849 if (os::Linux::supports_fast_thread_cpu_time()) {
4850 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4851 } else {
4852 return slow_thread_cpu_time(thread, true /* user + sys */);
4853 }
4854 }
4855
4856 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4857 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4858 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4859 } else {
4860 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
4861 }
4862 }
4863
4864 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4865 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4866 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4867 } else {
4868 return slow_thread_cpu_time(thread, user_sys_cpu_time);
4869 }
4870 }
4871
4872 //
4873 // -1 on error.
4874 //
4875
4876 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4877 static bool proc_pid_cpu_avail = true;
4878 static bool proc_task_unchecked = true;
4879 static const char *proc_stat_path = "/proc/%d/stat";
4880 pid_t tid = thread->osthread()->thread_id();
4881 int i;
4882 char *s;
4883 char stat[2048];
4884 int statlen;
4885 char proc_name[64];
4886 int count;
4887 long sys_time, user_time;
4888 char string[64];
4889 char cdummy;
4890 int idummy;
4891 long ldummy;
4892 FILE *fp;
4893
4894 // We first try accessing /proc/<pid>/cpu since this is faster to
4895 // process. If this file is not present (linux kernels 2.5 and above)
4896 // then we open /proc/<pid>/stat.
4897 if ( proc_pid_cpu_avail ) {
4898 sprintf(proc_name, "/proc/%d/cpu", tid);
4899 fp = fopen(proc_name, "r");
4900 if ( fp != NULL ) {
4901 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
4902 fclose(fp);
4903 if ( count != 3 ) return -1;
4904
4905 if (user_sys_cpu_time) {
4906 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4907 } else {
4908 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4909 }
4910 }
4911 else proc_pid_cpu_avail = false;
4912 }
4913
4914 // The /proc/<tid>/stat aggregates per-process usage on
4915 // new Linux kernels 2.6+ where NPTL is supported.
4916 // The /proc/self/task/<tid>/stat still has the per-thread usage.
4917 // See bug 6328462.
4918 // There can be no directory /proc/self/task on kernels 2.4 with NPTL
4919 // and possibly in some other cases, so we check its availability.
4920 if (proc_task_unchecked && os::Linux::is_NPTL()) {
4921 // This is executed only once
4922 proc_task_unchecked = false;
4923 fp = fopen("/proc/self/task", "r");
4924 if (fp != NULL) {
4925 proc_stat_path = "/proc/self/task/%d/stat";
4926 fclose(fp);
4927 }
4928 }
4929
4930 sprintf(proc_name, proc_stat_path, tid);
4931 fp = fopen(proc_name, "r");
4932 if ( fp == NULL ) return -1;
4933 statlen = fread(stat, 1, 2047, fp);
4934 stat[statlen] = '\0';
4935 fclose(fp);
4936
4937 // Skip pid and the command string. Note that we could be dealing with
4938 // weird command names, e.g. user could decide to rename java launcher
4939 // to "java 1.4.2 :)", then the stat file would look like
4940 // 1234 (java 1.4.2 :)) R ... ...
4941 // We don't really need to know the command string, just find the last
4942 // occurrence of ")" and then start parsing from there. See bug 4726580.
4943 s = strrchr(stat, ')');
4944 i = 0;
4945 if (s == NULL ) return -1;
4946
4947 // Skip blank chars
4948 do s++; while (isspace(*s));
4949
4950 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
4951 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
4952 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
4953 &user_time, &sys_time);
4954 if ( count != 13 ) return -1;
4955 if (user_sys_cpu_time) {
4956 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4957 } else {
4958 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4959 }
4960 }
4961
4962 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4963 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4964 info_ptr->may_skip_backward = false; // elapsed time not wall time
4965 info_ptr->may_skip_forward = false; // elapsed time not wall time
4966 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4967 }
4968
4969 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4970 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4971 info_ptr->may_skip_backward = false; // elapsed time not wall time
4972 info_ptr->may_skip_forward = false; // elapsed time not wall time
4973 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4974 }
4975
4976 bool os::is_thread_cpu_time_supported() {
4977 return true;
4978 }
4979
4980 // System loadavg support. Returns -1 if load average cannot be obtained.
4981 // Linux doesn't yet have a (official) notion of processor sets,
4982 // so just return the system wide load average.
4983 int os::loadavg(double loadavg[], int nelem) {
4984 return ::getloadavg(loadavg, nelem);
4985 }
4986
4987 void os::pause() {
4988 char filename[MAX_PATH];
4989 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4990 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4991 } else {
4992 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4993 }
4994
4995 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4996 if (fd != -1) {
4997 struct stat buf;
4998 ::close(fd);
4999 while (::stat(filename, &buf) == 0) {
5000 (void)::poll(NULL, 0, 100);
5001 }
5002 } else {
5003 jio_fprintf(stderr,
5004 "Could not open pause file '%s', continuing immediately.\n", filename);
5005 }
5006 }
5007
5008
5009 // Refer to the comments in os_solaris.cpp park-unpark.
5010 //
5011 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
5012 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
5013 // For specifics regarding the bug see GLIBC BUGID 261237 :
5014 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
5015 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
5016 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
5017 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
5018 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
5019 // and monitorenter when we're using 1-0 locking. All those operations may result in
5020 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
5021 // of libpthread avoids the problem, but isn't practical.
5022 //
5023 // Possible remedies:
5024 //
5025 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
5026 // This is palliative and probabilistic, however. If the thread is preempted
5027 // between the call to compute_abstime() and pthread_cond_timedwait(), more
5028 // than the minimum period may have passed, and the abstime may be stale (in the
5029 // past) resultin in a hang. Using this technique reduces the odds of a hang
5030 // but the JVM is still vulnerable, particularly on heavily loaded systems.
5031 //
5032 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
5033 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
5034 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
5035 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
5036 // thread.
5037 //
5038 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
5039 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
5040 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
5041 // This also works well. In fact it avoids kernel-level scalability impediments
5042 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
5043 // timers in a graceful fashion.
5044 //
5045 // 4. When the abstime value is in the past it appears that control returns
5046 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
5047 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
5048 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
5049 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
5050 // It may be possible to avoid reinitialization by checking the return
5051 // value from pthread_cond_timedwait(). In addition to reinitializing the
5052 // condvar we must establish the invariant that cond_signal() is only called
5053 // within critical sections protected by the adjunct mutex. This prevents
5054 // cond_signal() from "seeing" a condvar that's in the midst of being
5055 // reinitialized or that is corrupt. Sadly, this invariant obviates the
5056 // desirable signal-after-unlock optimization that avoids futile context switching.
5057 //
5058 // I'm also concerned that some versions of NTPL might allocate an auxilliary
5059 // structure when a condvar is used or initialized. cond_destroy() would
5060 // release the helper structure. Our reinitialize-after-timedwait fix
5061 // put excessive stress on malloc/free and locks protecting the c-heap.
5062 //
5063 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
5064 // It may be possible to refine (4) by checking the kernel and NTPL verisons
5065 // and only enabling the work-around for vulnerable environments.
5066
5067 // utility to compute the abstime argument to timedwait:
5068 // millis is the relative timeout time
5069 // abstime will be the absolute timeout time
5070 // TODO: replace compute_abstime() with unpackTime()
5071
5072 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
5073 if (millis < 0) millis = 0;
5074 struct timeval now;
5075 int status = gettimeofday(&now, NULL);
5076 assert(status == 0, "gettimeofday");
5077 jlong seconds = millis / 1000;
5078 millis %= 1000;
5079 if (seconds > 50000000) { // see man cond_timedwait(3T)
5080 seconds = 50000000;
5081 }
5082 abstime->tv_sec = now.tv_sec + seconds;
5083 long usec = now.tv_usec + millis * 1000;
5084 if (usec >= 1000000) {
5085 abstime->tv_sec += 1;
5086 usec -= 1000000;
5087 }
5088 abstime->tv_nsec = usec * 1000;
5089 return abstime;
5090 }
5091
5092
5093 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
5094 // Conceptually TryPark() should be equivalent to park(0).
5095
5096 int os::PlatformEvent::TryPark() {
5097 for (;;) {
5098 const int v = _Event ;
5099 guarantee ((v == 0) || (v == 1), "invariant") ;
5100 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
5101 }
5102 }
5103
5104 void os::PlatformEvent::park() { // AKA "down()"
5105 // Invariant: Only the thread associated with the Event/PlatformEvent
5106 // may call park().
5107 // TODO: assert that _Assoc != NULL or _Assoc == Self
5108 int v ;
5109 for (;;) {
5110 v = _Event ;
5111 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5112 }
5113 guarantee (v >= 0, "invariant") ;
5114 if (v == 0) {
5115 // Do this the hard way by blocking ...
5116 int status = pthread_mutex_lock(_mutex);
5117 assert_status(status == 0, status, "mutex_lock");
5118 guarantee (_nParked == 0, "invariant") ;
5119 ++ _nParked ;
5120 while (_Event < 0) {
5121 status = pthread_cond_wait(_cond, _mutex);
5122 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5123 // Treat this the same as if the wait was interrupted
5124 if (status == ETIME) { status = EINTR; }
5125 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5126 }
5127 -- _nParked ;
5128
5129 // In theory we could move the ST of 0 into _Event past the unlock(),
5130 // but then we'd need a MEMBAR after the ST.
5131 _Event = 0 ;
5132 status = pthread_mutex_unlock(_mutex);
5133 assert_status(status == 0, status, "mutex_unlock");
5134 }
5135 guarantee (_Event >= 0, "invariant") ;
5136 }
5137
5138 int os::PlatformEvent::park(jlong millis) {
5139 guarantee (_nParked == 0, "invariant") ;
5140
5141 int v ;
5142 for (;;) {
5143 v = _Event ;
5144 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5145 }
5146 guarantee (v >= 0, "invariant") ;
5147 if (v != 0) return OS_OK ;
5148
5149 // We do this the hard way, by blocking the thread.
5150 // Consider enforcing a minimum timeout value.
5151 struct timespec abst;
5152 compute_abstime(&abst, millis);
5153
5154 int ret = OS_TIMEOUT;
5155 int status = pthread_mutex_lock(_mutex);
5156 assert_status(status == 0, status, "mutex_lock");
5157 guarantee (_nParked == 0, "invariant") ;
5158 ++_nParked ;
5159
5160 // Object.wait(timo) will return because of
5161 // (a) notification
5162 // (b) timeout
5163 // (c) thread.interrupt
5164 //
5165 // Thread.interrupt and object.notify{All} both call Event::set.
5166 // That is, we treat thread.interrupt as a special case of notification.
5167 // The underlying Solaris implementation, cond_timedwait, admits
5168 // spurious/premature wakeups, but the JLS/JVM spec prevents the
5169 // JVM from making those visible to Java code. As such, we must
5170 // filter out spurious wakeups. We assume all ETIME returns are valid.
5171 //
5172 // TODO: properly differentiate simultaneous notify+interrupt.
5173 // In that case, we should propagate the notify to another waiter.
5174
5175 while (_Event < 0) {
5176 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
5177 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5178 pthread_cond_destroy (_cond);
5179 pthread_cond_init (_cond, NULL) ;
5180 }
5181 assert_status(status == 0 || status == EINTR ||
5182 status == ETIME || status == ETIMEDOUT,
5183 status, "cond_timedwait");
5184 if (!FilterSpuriousWakeups) break ; // previous semantics
5185 if (status == ETIME || status == ETIMEDOUT) break ;
5186 // We consume and ignore EINTR and spurious wakeups.
5187 }
5188 --_nParked ;
5189 if (_Event >= 0) {
5190 ret = OS_OK;
5191 }
5192 _Event = 0 ;
5193 status = pthread_mutex_unlock(_mutex);
5194 assert_status(status == 0, status, "mutex_unlock");
5195 assert (_nParked == 0, "invariant") ;
5196 return ret;
5197 }
5198
5199 void os::PlatformEvent::unpark() {
5200 int v, AnyWaiters ;
5201 for (;;) {
5202 v = _Event ;
5203 if (v > 0) {
5204 // The LD of _Event could have reordered or be satisfied
5205 // by a read-aside from this processor's write buffer.
5206 // To avoid problems execute a barrier and then
5207 // ratify the value.
5208 OrderAccess::fence() ;
5209 if (_Event == v) return ;
5210 continue ;
5211 }
5212 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
5213 }
5214 if (v < 0) {
5215 // Wait for the thread associated with the event to vacate
5216 int status = pthread_mutex_lock(_mutex);
5217 assert_status(status == 0, status, "mutex_lock");
5218 AnyWaiters = _nParked ;
5219 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ;
5220 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5221 AnyWaiters = 0 ;
5222 pthread_cond_signal (_cond);
5223 }
5224 status = pthread_mutex_unlock(_mutex);
5225 assert_status(status == 0, status, "mutex_unlock");
5226 if (AnyWaiters != 0) {
5227 status = pthread_cond_signal(_cond);
5228 assert_status(status == 0, status, "cond_signal");
5229 }
5230 }
5231
5232 // Note that we signal() _after dropping the lock for "immortal" Events.
5233 // This is safe and avoids a common class of futile wakeups. In rare
5234 // circumstances this can cause a thread to return prematurely from
5235 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5236 // simply re-test the condition and re-park itself.
5237 }
5238
5239
5240 // JSR166
5241 // -------------------------------------------------------
5242
5243 /*
5244 * The solaris and linux implementations of park/unpark are fairly
5245 * conservative for now, but can be improved. They currently use a
5246 * mutex/condvar pair, plus a a count.
5247 * Park decrements count if > 0, else does a condvar wait. Unpark
5248 * sets count to 1 and signals condvar. Only one thread ever waits
5249 * on the condvar. Contention seen when trying to park implies that someone
5250 * is unparking you, so don't wait. And spurious returns are fine, so there
5251 * is no need to track notifications.
5252 */
5253
5254 #define MAX_SECS 100000000
5255 /*
5256 * This code is common to linux and solaris and will be moved to a
5257 * common place in dolphin.
5258 *
5259 * The passed in time value is either a relative time in nanoseconds
5260 * or an absolute time in milliseconds. Either way it has to be unpacked
5261 * into suitable seconds and nanoseconds components and stored in the
5262 * given timespec structure.
5263 * Given time is a 64-bit value and the time_t used in the timespec is only
5264 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5265 * overflow if times way in the future are given. Further on Solaris versions
5266 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5267 * number of seconds, in abstime, is less than current_time + 100,000,000.
5268 * As it will be 28 years before "now + 100000000" will overflow we can
5269 * ignore overflow and just impose a hard-limit on seconds using the value
5270 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5271 * years from "now".
5272 */
5273
5274 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5275 assert (time > 0, "convertTime");
5276
5277 struct timeval now;
5278 int status = gettimeofday(&now, NULL);
5279 assert(status == 0, "gettimeofday");
5280
5281 time_t max_secs = now.tv_sec + MAX_SECS;
5282
5283 if (isAbsolute) {
5284 jlong secs = time / 1000;
5285 if (secs > max_secs) {
5286 absTime->tv_sec = max_secs;
5287 }
5288 else {
5289 absTime->tv_sec = secs;
5290 }
5291 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5292 }
5293 else {
5294 jlong secs = time / NANOSECS_PER_SEC;
5295 if (secs >= MAX_SECS) {
5296 absTime->tv_sec = max_secs;
5297 absTime->tv_nsec = 0;
5298 }
5299 else {
5300 absTime->tv_sec = now.tv_sec + secs;
5301 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5302 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5303 absTime->tv_nsec -= NANOSECS_PER_SEC;
5304 ++absTime->tv_sec; // note: this must be <= max_secs
5305 }
5306 }
5307 }
5308 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5309 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5310 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5311 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5312 }
5313
5314 void Parker::park(bool isAbsolute, jlong time) {
5315 // Optional fast-path check:
5316 // Return immediately if a permit is available.
5317 if (_counter > 0) {
5318 _counter = 0 ;
5319 OrderAccess::fence();
5320 return ;
5321 }
5322
5323 Thread* thread = Thread::current();
5324 assert(thread->is_Java_thread(), "Must be JavaThread");
5325 JavaThread *jt = (JavaThread *)thread;
5326
5327 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5328 // Check interrupt before trying to wait
5329 if (Thread::is_interrupted(thread, false)) {
5330 return;
5331 }
5332
5333 // Next, demultiplex/decode time arguments
5334 timespec absTime;
5335 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
5336 return;
5337 }
5338 if (time > 0) {
5339 unpackTime(&absTime, isAbsolute, time);
5340 }
5341
5342
5343 // Enter safepoint region
5344 // Beware of deadlocks such as 6317397.
5345 // The per-thread Parker:: mutex is a classic leaf-lock.
5346 // In particular a thread must never block on the Threads_lock while
5347 // holding the Parker:: mutex. If safepoints are pending both the
5348 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5349 ThreadBlockInVM tbivm(jt);
5350
5351 // Don't wait if cannot get lock since interference arises from
5352 // unblocking. Also. check interrupt before trying wait
5353 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5354 return;
5355 }
5356
5357 int status ;
5358 if (_counter > 0) { // no wait needed
5359 _counter = 0;
5360 status = pthread_mutex_unlock(_mutex);
5361 assert (status == 0, "invariant") ;
5362 OrderAccess::fence();
5363 return;
5364 }
5365
5366 #ifdef ASSERT
5367 // Don't catch signals while blocked; let the running threads have the signals.
5368 // (This allows a debugger to break into the running thread.)
5369 sigset_t oldsigs;
5370 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5371 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5372 #endif
5373
5374 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5375 jt->set_suspend_equivalent();
5376 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5377
5378 if (time == 0) {
5379 status = pthread_cond_wait (_cond, _mutex) ;
5380 } else {
5381 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
5382 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5383 pthread_cond_destroy (_cond) ;
5384 pthread_cond_init (_cond, NULL);
5385 }
5386 }
5387 assert_status(status == 0 || status == EINTR ||
5388 status == ETIME || status == ETIMEDOUT,
5389 status, "cond_timedwait");
5390
5391 #ifdef ASSERT
5392 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5393 #endif
5394
5395 _counter = 0 ;
5396 status = pthread_mutex_unlock(_mutex) ;
5397 assert_status(status == 0, status, "invariant") ;
5398 // If externally suspended while waiting, re-suspend
5399 if (jt->handle_special_suspend_equivalent_condition()) {
5400 jt->java_suspend_self();
5401 }
5402
5403 OrderAccess::fence();
5404 }
5405
5406 void Parker::unpark() {
5407 int s, status ;
5408 status = pthread_mutex_lock(_mutex);
5409 assert (status == 0, "invariant") ;
5410 s = _counter;
5411 _counter = 1;
5412 if (s < 1) {
5413 if (WorkAroundNPTLTimedWaitHang) {
5414 status = pthread_cond_signal (_cond) ;
5415 assert (status == 0, "invariant") ;
5416 status = pthread_mutex_unlock(_mutex);
5417 assert (status == 0, "invariant") ;
5418 } else {
5419 status = pthread_mutex_unlock(_mutex);
5420 assert (status == 0, "invariant") ;
5421 status = pthread_cond_signal (_cond) ;
5422 assert (status == 0, "invariant") ;
5423 }
5424 } else {
5425 pthread_mutex_unlock(_mutex);
5426 assert (status == 0, "invariant") ;
5427 }
5428 }
5429
5430
5431 extern char** environ;
5432
5433 #ifndef __NR_fork
5434 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
5435 #endif
5436
5437 #ifndef __NR_execve
5438 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
5439 #endif
5440
5441 // Run the specified command in a separate process. Return its exit value,
5442 // or -1 on failure (e.g. can't fork a new process).
5443 // Unlike system(), this function can be called from signal handler. It
5444 // doesn't block SIGINT et al.
5445 int os::fork_and_exec(char* cmd) {
5446 const char * argv[4] = {"sh", "-c", cmd, NULL};
5447
5448 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
5449 // pthread_atfork handlers and reset pthread library. All we need is a
5450 // separate process to execve. Make a direct syscall to fork process.
5451 // On IA64 there's no fork syscall, we have to use fork() and hope for
5452 // the best...
5453 pid_t pid = NOT_IA64(syscall(__NR_fork);)
5454 IA64_ONLY(fork();)
5455
5456 if (pid < 0) {
5457 // fork failed
5458 return -1;
5459
5460 } else if (pid == 0) {
5461 // child process
5462
5463 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
5464 // first to kill every thread on the thread list. Because this list is
5465 // not reset by fork() (see notes above), execve() will instead kill
5466 // every thread in the parent process. We know this is the only thread
5467 // in the new process, so make a system call directly.
5468 // IA64 should use normal execve() from glibc to match the glibc fork()
5469 // above.
5470 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
5471 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
5472
5473 // execve failed
5474 _exit(-1);
5475
5476 } else {
5477 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5478 // care about the actual exit code, for now.
5479
5480 int status;
5481
5482 // Wait for the child process to exit. This returns immediately if
5483 // the child has already exited. */
5484 while (waitpid(pid, &status, 0) < 0) {
5485 switch (errno) {
5486 case ECHILD: return 0;
5487 case EINTR: break;
5488 default: return -1;
5489 }
5490 }
5491
5492 if (WIFEXITED(status)) {
5493 // The child exited normally; get its exit code.
5494 return WEXITSTATUS(status);
5495 } else if (WIFSIGNALED(status)) {
5496 // The child exited because of a signal
5497 // The best value to return is 0x80 + signal number,
5498 // because that is what all Unix shells do, and because
5499 // it allows callers to distinguish between process exit and
5500 // process death by signal.
5501 return 0x80 + WTERMSIG(status);
5502 } else {
5503 // Unknown exit code; pass it through
5504 return status;
5505 }
5506 }
5507 }
5508
5509 // is_headless_jre()
5510 //
5511 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5512 // in order to report if we are running in a headless jre
5513 //
5514 // Since JDK8 xawt/libmawt.so was moved into the same directory
5515 // as libawt.so, and renamed libawt_xawt.so
5516 //
5517 bool os::is_headless_jre() {
5518 struct stat statbuf;
5519 char buf[MAXPATHLEN];
5520 char libmawtpath[MAXPATHLEN];
5521 const char *xawtstr = "/xawt/libmawt.so";
5522 const char *new_xawtstr = "/libawt_xawt.so";
5523 char *p;
5524
5525 // Get path to libjvm.so
5526 os::jvm_path(buf, sizeof(buf));
5527
5528 // Get rid of libjvm.so
5529 p = strrchr(buf, '/');
5530 if (p == NULL) return false;
5531 else *p = '\0';
5532
5533 // Get rid of client or server
5534 p = strrchr(buf, '/');
5535 if (p == NULL) return false;
5536 else *p = '\0';
5537
5538 // check xawt/libmawt.so
5539 strcpy(libmawtpath, buf);
5540 strcat(libmawtpath, xawtstr);
5541 if (::stat(libmawtpath, &statbuf) == 0) return false;
5542
5543 // check libawt_xawt.so
5544 strcpy(libmawtpath, buf);
5545 strcat(libmawtpath, new_xawtstr);
5546 if (::stat(libmawtpath, &statbuf) == 0) return false;
5547
5548 return true;
5549 }
5550
5551 // Get the default path to the core file
5552 // Returns the length of the string
5553 int os::get_core_path(char* buffer, size_t bufferSize) {
5554 const char* p = get_current_directory(buffer, bufferSize);
5555
5556 if (p == NULL) {
5557 assert(p != NULL, "failed to get current directory");
5558 return 0;
5559 }
5560
5561 return strlen(buffer);
5562 }
5563
5564 #ifdef JAVASE_EMBEDDED
5565 //
5566 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory.
5567 //
5568 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL;
5569
5570 // ctor
5571 //
5572 MemNotifyThread::MemNotifyThread(int fd): Thread() {
5573 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread");
5574 _fd = fd;
5575
5576 if (os::create_thread(this, os::os_thread)) {
5577 _memnotify_thread = this;
5578 os::set_priority(this, NearMaxPriority);
5579 os::start_thread(this);
5580 }
5581 }
5582
5583 // Where all the work gets done
5584 //
5585 void MemNotifyThread::run() {
5586 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread");
5587
5588 // Set up the select arguments
5589 fd_set rfds;
5590 if (_fd != -1) {
5591 FD_ZERO(&rfds);
5592 FD_SET(_fd, &rfds);
5593 }
5594
5595 // Now wait for the mem_notify device to wake up
5596 while (1) {
5597 // Wait for the mem_notify device to signal us..
5598 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL);
5599 if (rc == -1) {
5600 perror("select!\n");
5601 break;
5602 } else if (rc) {
5603 //ssize_t free_before = os::available_memory();
5604 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024);
5605
5606 // The kernel is telling us there is not much memory left...
5607 // try to do something about that
5608
5609 // If we are not already in a GC, try one.
5610 if (!Universe::heap()->is_gc_active()) {
5611 Universe::heap()->collect(GCCause::_allocation_failure);
5612
5613 //ssize_t free_after = os::available_memory();
5614 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024);
5615 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024);
5616 }
5617 // We might want to do something like the following if we find the GC's are not helping...
5618 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true);
5619 }
5620 }
5621 }
5622
5623 //
5624 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it.
5625 //
5626 void MemNotifyThread::start() {
5627 int fd;
5628 fd = open ("/dev/mem_notify", O_RDONLY, 0);
5629 if (fd < 0) {
5630 return;
5631 }
5632
5633 if (memnotify_thread() == NULL) {
5634 new MemNotifyThread(fd);
5635 }
5636 }
5637 #endif // JAVASE_EMBEDDED