1 /*
2 * Copyright (c) 1999, 2011, 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 #define SEC_IN_NANOSECS 1000000000LL
131
132 #define LARGEPAGES_BIT (1 << 6)
133 ////////////////////////////////////////////////////////////////////////////////
134 // global variables
135 julong os::Linux::_physical_memory = 0;
136
137 address os::Linux::_initial_thread_stack_bottom = NULL;
138 uintptr_t os::Linux::_initial_thread_stack_size = 0;
139
140 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
141 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
142 Mutex* os::Linux::_createThread_lock = NULL;
143 pthread_t os::Linux::_main_thread;
144 int os::Linux::_page_size = -1;
145 bool os::Linux::_is_floating_stack = false;
146 bool os::Linux::_is_NPTL = false;
147 bool os::Linux::_supports_fast_thread_cpu_time = false;
148 const char * os::Linux::_glibc_version = NULL;
149 const char * os::Linux::_libpthread_version = NULL;
150
151 static jlong initial_time_count=0;
152
153 static int clock_tics_per_sec = 100;
154
155 // For diagnostics to print a message once. see run_periodic_checks
156 static sigset_t check_signal_done;
157 static bool check_signals = true;;
158
159 static pid_t _initial_pid = 0;
160
161 /* Signal number used to suspend/resume a thread */
162
163 /* do not use any signal number less than SIGSEGV, see 4355769 */
164 static int SR_signum = SIGUSR2;
165 sigset_t SR_sigset;
166
167 /* Used to protect dlsym() calls */
168 static pthread_mutex_t dl_mutex;
169
170 #ifdef JAVASE_EMBEDDED
171 class MemNotifyThread: public Thread {
172 friend class VMStructs;
173 public:
174 virtual void run();
175
176 private:
177 static MemNotifyThread* _memnotify_thread;
178 int _fd;
179
180 public:
181
182 // Constructor
183 MemNotifyThread(int fd);
184
185 // Tester
186 bool is_memnotify_thread() const { return true; }
187
188 // Printing
189 char* name() const { return (char*)"Linux MemNotify Thread"; }
190
191 // Returns the single instance of the MemNotifyThread
192 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }
193
194 // Create and start the single instance of MemNotifyThread
195 static void start();
196 };
197 #endif // JAVASE_EMBEDDED
198
199 // utility functions
200
201 static int SR_initialize();
202 static int SR_finalize();
203
204 julong os::available_memory() {
205 return Linux::available_memory();
206 }
207
208 julong os::Linux::available_memory() {
209 // values in struct sysinfo are "unsigned long"
210 struct sysinfo si;
211 sysinfo(&si);
212
213 return (julong)si.freeram * si.mem_unit;
214 }
215
216 julong os::physical_memory() {
217 return Linux::physical_memory();
218 }
219
220 julong os::allocatable_physical_memory(julong size) {
221 #ifdef _LP64
222 return size;
223 #else
224 julong result = MIN2(size, (julong)3800*M);
225 if (!is_allocatable(result)) {
226 // See comments under solaris for alignment considerations
227 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
228 result = MIN2(size, reasonable_size);
229 }
230 return result;
231 #endif // _LP64
232 }
233
234 ////////////////////////////////////////////////////////////////////////////////
235 // environment support
236
237 bool os::getenv(const char* name, char* buf, int len) {
238 const char* val = ::getenv(name);
239 if (val != NULL && strlen(val) < (size_t)len) {
240 strcpy(buf, val);
241 return true;
242 }
243 if (len > 0) buf[0] = 0; // return a null string
244 return false;
245 }
246
247
248 // Return true if user is running as root.
249
250 bool os::have_special_privileges() {
251 static bool init = false;
252 static bool privileges = false;
253 if (!init) {
254 privileges = (getuid() != geteuid()) || (getgid() != getegid());
255 init = true;
256 }
257 return privileges;
258 }
259
260
261 #ifndef SYS_gettid
262 // i386: 224, ia64: 1105, amd64: 186, sparc 143
263 #ifdef __ia64__
264 #define SYS_gettid 1105
265 #elif __i386__
266 #define SYS_gettid 224
267 #elif __amd64__
268 #define SYS_gettid 186
269 #elif __sparc__
270 #define SYS_gettid 143
271 #else
272 #error define gettid for the arch
273 #endif
274 #endif
275
276 // Cpu architecture string
277 #if defined(ZERO)
278 static char cpu_arch[] = ZERO_LIBARCH;
279 #elif defined(IA64)
280 static char cpu_arch[] = "ia64";
281 #elif defined(IA32)
282 static char cpu_arch[] = "i386";
283 #elif defined(AMD64)
284 static char cpu_arch[] = "amd64";
285 #elif defined(ARM)
286 static char cpu_arch[] = "arm";
287 #elif defined(PPC)
288 static char cpu_arch[] = "ppc";
289 #elif defined(SPARC)
290 # ifdef _LP64
291 static char cpu_arch[] = "sparcv9";
292 # else
293 static char cpu_arch[] = "sparc";
294 # endif
295 #else
296 #error Add appropriate cpu_arch setting
297 #endif
298
299
300 // pid_t gettid()
301 //
302 // Returns the kernel thread id of the currently running thread. Kernel
303 // thread id is used to access /proc.
304 //
305 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
306 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
307 //
308 pid_t os::Linux::gettid() {
309 int rslt = syscall(SYS_gettid);
310 if (rslt == -1) {
311 // old kernel, no NPTL support
312 return getpid();
313 } else {
314 return (pid_t)rslt;
315 }
316 }
317
318 // Most versions of linux have a bug where the number of processors are
319 // determined by looking at the /proc file system. In a chroot environment,
320 // the system call returns 1. This causes the VM to act as if it is
321 // a single processor and elide locking (see is_MP() call).
322 static bool unsafe_chroot_detected = false;
323 static const char *unstable_chroot_error = "/proc file system not found.\n"
324 "Java may be unstable running multithreaded in a chroot "
325 "environment on Linux when /proc filesystem is not mounted.";
326
327 void os::Linux::initialize_system_info() {
328 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
329 if (processor_count() == 1) {
330 pid_t pid = os::Linux::gettid();
331 char fname[32];
332 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
333 FILE *fp = fopen(fname, "r");
334 if (fp == NULL) {
335 unsafe_chroot_detected = true;
336 } else {
337 fclose(fp);
338 }
339 }
340 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
341 assert(processor_count() > 0, "linux error");
342 }
343
344 void os::init_system_properties_values() {
345 // char arch[12];
346 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
347
348 // The next steps are taken in the product version:
349 //
350 // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
351 // This library should be located at:
352 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
353 //
354 // If "/jre/lib/" appears at the right place in the path, then we
355 // assume libjvm[_g].so is installed in a JDK and we use this path.
356 //
357 // Otherwise exit with message: "Could not create the Java virtual machine."
358 //
359 // The following extra steps are taken in the debugging version:
360 //
361 // If "/jre/lib/" does NOT appear at the right place in the path
362 // instead of exit check for $JAVA_HOME environment variable.
363 //
364 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
365 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
366 // it looks like libjvm[_g].so is installed there
367 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
368 //
369 // Otherwise exit.
370 //
371 // Important note: if the location of libjvm.so changes this
372 // code needs to be changed accordingly.
373
374 // The next few definitions allow the code to be verbatim:
375 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n))
376 #define getenv(n) ::getenv(n)
377
378 /*
379 * See ld(1):
380 * The linker uses the following search paths to locate required
381 * shared libraries:
382 * 1: ...
383 * ...
384 * 7: The default directories, normally /lib and /usr/lib.
385 */
386 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
387 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
388 #else
389 #define DEFAULT_LIBPATH "/lib:/usr/lib"
390 #endif
391
392 #define EXTENSIONS_DIR "/lib/ext"
393 #define ENDORSED_DIR "/lib/endorsed"
394 #define REG_DIR "/usr/java/packages"
395
396 {
397 /* sysclasspath, java_home, dll_dir */
398 {
399 char *home_path;
400 char *dll_path;
401 char *pslash;
402 char buf[MAXPATHLEN];
403 os::jvm_path(buf, sizeof(buf));
404
405 // Found the full path to libjvm.so.
406 // Now cut the path to <java_home>/jre if we can.
407 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
408 pslash = strrchr(buf, '/');
409 if (pslash != NULL)
410 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
411 dll_path = malloc(strlen(buf) + 1);
412 if (dll_path == NULL)
413 return;
414 strcpy(dll_path, buf);
415 Arguments::set_dll_dir(dll_path);
416
417 if (pslash != NULL) {
418 pslash = strrchr(buf, '/');
419 if (pslash != NULL) {
420 *pslash = '\0'; /* get rid of /<arch> */
421 pslash = strrchr(buf, '/');
422 if (pslash != NULL)
423 *pslash = '\0'; /* get rid of /lib */
424 }
425 }
426
427 home_path = malloc(strlen(buf) + 1);
428 if (home_path == NULL)
429 return;
430 strcpy(home_path, buf);
431 Arguments::set_java_home(home_path);
432
433 if (!set_boot_path('/', ':'))
434 return;
435 }
436
437 /*
438 * Where to look for native libraries
439 *
440 * Note: Due to a legacy implementation, most of the library path
441 * is set in the launcher. This was to accomodate linking restrictions
442 * on legacy Linux implementations (which are no longer supported).
443 * Eventually, all the library path setting will be done here.
444 *
445 * However, to prevent the proliferation of improperly built native
446 * libraries, the new path component /usr/java/packages is added here.
447 * Eventually, all the library path setting will be done here.
448 */
449 {
450 char *ld_library_path;
451
452 /*
453 * Construct the invariant part of ld_library_path. Note that the
454 * space for the colon and the trailing null are provided by the
455 * nulls included by the sizeof operator (so actually we allocate
456 * a byte more than necessary).
457 */
458 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
459 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
460 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
461
462 /*
463 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
464 * should always exist (until the legacy problem cited above is
465 * addressed).
466 */
467 char *v = getenv("LD_LIBRARY_PATH");
468 if (v != NULL) {
469 char *t = ld_library_path;
470 /* That's +1 for the colon and +1 for the trailing '\0' */
471 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
472 sprintf(ld_library_path, "%s:%s", v, t);
473 }
474 Arguments::set_library_path(ld_library_path);
475 }
476
477 /*
478 * Extensions directories.
479 *
480 * Note that the space for the colon and the trailing null are provided
481 * by the nulls included by the sizeof operator (so actually one byte more
482 * than necessary is allocated).
483 */
484 {
485 char *buf = malloc(strlen(Arguments::get_java_home()) +
486 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
487 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
488 Arguments::get_java_home());
489 Arguments::set_ext_dirs(buf);
490 }
491
492 /* Endorsed standards default directory. */
493 {
494 char * buf;
495 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
496 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
497 Arguments::set_endorsed_dirs(buf);
498 }
499 }
500
501 #undef malloc
502 #undef getenv
503 #undef EXTENSIONS_DIR
504 #undef ENDORSED_DIR
505
506 // Done
507 return;
508 }
509
510 ////////////////////////////////////////////////////////////////////////////////
511 // breakpoint support
512
513 void os::breakpoint() {
514 BREAKPOINT;
515 }
516
517 extern "C" void breakpoint() {
518 // use debugger to set breakpoint here
519 }
520
521 ////////////////////////////////////////////////////////////////////////////////
522 // signal support
523
524 debug_only(static bool signal_sets_initialized = false);
525 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
526
527 bool os::Linux::is_sig_ignored(int sig) {
528 struct sigaction oact;
529 sigaction(sig, (struct sigaction*)NULL, &oact);
530 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
531 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
532 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
533 return true;
534 else
535 return false;
536 }
537
538 void os::Linux::signal_sets_init() {
539 // Should also have an assertion stating we are still single-threaded.
540 assert(!signal_sets_initialized, "Already initialized");
541 // Fill in signals that are necessarily unblocked for all threads in
542 // the VM. Currently, we unblock the following signals:
543 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
544 // by -Xrs (=ReduceSignalUsage));
545 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
546 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
547 // the dispositions or masks wrt these signals.
548 // Programs embedding the VM that want to use the above signals for their
549 // own purposes must, at this time, use the "-Xrs" option to prevent
550 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
551 // (See bug 4345157, and other related bugs).
552 // In reality, though, unblocking these signals is really a nop, since
553 // these signals are not blocked by default.
554 sigemptyset(&unblocked_sigs);
555 sigemptyset(&allowdebug_blocked_sigs);
556 sigaddset(&unblocked_sigs, SIGILL);
557 sigaddset(&unblocked_sigs, SIGSEGV);
558 sigaddset(&unblocked_sigs, SIGBUS);
559 sigaddset(&unblocked_sigs, SIGFPE);
560 sigaddset(&unblocked_sigs, SR_signum);
561
562 if (!ReduceSignalUsage) {
563 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
564 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
565 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
566 }
567 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
568 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
569 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
570 }
571 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
572 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
573 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
574 }
575 }
576 // Fill in signals that are blocked by all but the VM thread.
577 sigemptyset(&vm_sigs);
578 if (!ReduceSignalUsage)
579 sigaddset(&vm_sigs, BREAK_SIGNAL);
580 debug_only(signal_sets_initialized = true);
581
582 }
583
584 // These are signals that are unblocked while a thread is running Java.
585 // (For some reason, they get blocked by default.)
586 sigset_t* os::Linux::unblocked_signals() {
587 assert(signal_sets_initialized, "Not initialized");
588 return &unblocked_sigs;
589 }
590
591 // These are the signals that are blocked while a (non-VM) thread is
592 // running Java. Only the VM thread handles these signals.
593 sigset_t* os::Linux::vm_signals() {
594 assert(signal_sets_initialized, "Not initialized");
595 return &vm_sigs;
596 }
597
598 // These are signals that are blocked during cond_wait to allow debugger in
599 sigset_t* os::Linux::allowdebug_blocked_signals() {
600 assert(signal_sets_initialized, "Not initialized");
601 return &allowdebug_blocked_sigs;
602 }
603
604 void os::Linux::hotspot_sigmask(Thread* thread) {
605
606 //Save caller's signal mask before setting VM signal mask
607 sigset_t caller_sigmask;
608 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
609
610 OSThread* osthread = thread->osthread();
611 osthread->set_caller_sigmask(caller_sigmask);
612
613 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
614
615 if (!ReduceSignalUsage) {
616 if (thread->is_VM_thread()) {
617 // Only the VM thread handles BREAK_SIGNAL ...
618 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
619 } else {
620 // ... all other threads block BREAK_SIGNAL
621 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
622 }
623 }
624 }
625
626 //////////////////////////////////////////////////////////////////////////////
627 // detecting pthread library
628
629 void os::Linux::libpthread_init() {
630 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
631 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
632 // generic name for earlier versions.
633 // Define macros here so we can build HotSpot on old systems.
634 # ifndef _CS_GNU_LIBC_VERSION
635 # define _CS_GNU_LIBC_VERSION 2
636 # endif
637 # ifndef _CS_GNU_LIBPTHREAD_VERSION
638 # define _CS_GNU_LIBPTHREAD_VERSION 3
639 # endif
640
641 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
642 if (n > 0) {
643 char *str = (char *)malloc(n);
644 confstr(_CS_GNU_LIBC_VERSION, str, n);
645 os::Linux::set_glibc_version(str);
646 } else {
647 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
648 static char _gnu_libc_version[32];
649 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
650 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
651 os::Linux::set_glibc_version(_gnu_libc_version);
652 }
653
654 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
655 if (n > 0) {
656 char *str = (char *)malloc(n);
657 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
658 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
659 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
660 // is the case. LinuxThreads has a hard limit on max number of threads.
661 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
662 // On the other hand, NPTL does not have such a limit, sysconf()
663 // will return -1 and errno is not changed. Check if it is really NPTL.
664 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
665 strstr(str, "NPTL") &&
666 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
667 free(str);
668 os::Linux::set_libpthread_version("linuxthreads");
669 } else {
670 os::Linux::set_libpthread_version(str);
671 }
672 } else {
673 // glibc before 2.3.2 only has LinuxThreads.
674 os::Linux::set_libpthread_version("linuxthreads");
675 }
676
677 if (strstr(libpthread_version(), "NPTL")) {
678 os::Linux::set_is_NPTL();
679 } else {
680 os::Linux::set_is_LinuxThreads();
681 }
682
683 // LinuxThreads have two flavors: floating-stack mode, which allows variable
684 // stack size; and fixed-stack mode. NPTL is always floating-stack.
685 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
686 os::Linux::set_is_floating_stack();
687 }
688 }
689
690 /////////////////////////////////////////////////////////////////////////////
691 // thread stack
692
693 // Force Linux kernel to expand current thread stack. If "bottom" is close
694 // to the stack guard, caller should block all signals.
695 //
696 // MAP_GROWSDOWN:
697 // A special mmap() flag that is used to implement thread stacks. It tells
698 // kernel that the memory region should extend downwards when needed. This
699 // allows early versions of LinuxThreads to only mmap the first few pages
700 // when creating a new thread. Linux kernel will automatically expand thread
701 // stack as needed (on page faults).
702 //
703 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
704 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
705 // region, it's hard to tell if the fault is due to a legitimate stack
706 // access or because of reading/writing non-exist memory (e.g. buffer
707 // overrun). As a rule, if the fault happens below current stack pointer,
708 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
709 // application (see Linux kernel fault.c).
710 //
711 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
712 // stack overflow detection.
713 //
714 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
715 // not use this flag. However, the stack of initial thread is not created
716 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
717 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
718 // and then attach the thread to JVM.
719 //
720 // To get around the problem and allow stack banging on Linux, we need to
721 // manually expand thread stack after receiving the SIGSEGV.
722 //
723 // There are two ways to expand thread stack to address "bottom", we used
724 // both of them in JVM before 1.5:
725 // 1. adjust stack pointer first so that it is below "bottom", and then
726 // touch "bottom"
727 // 2. mmap() the page in question
728 //
729 // Now alternate signal stack is gone, it's harder to use 2. For instance,
730 // if current sp is already near the lower end of page 101, and we need to
731 // call mmap() to map page 100, it is possible that part of the mmap() frame
732 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
733 // That will destroy the mmap() frame and cause VM to crash.
734 //
735 // The following code works by adjusting sp first, then accessing the "bottom"
736 // page to force a page fault. Linux kernel will then automatically expand the
737 // stack mapping.
738 //
739 // _expand_stack_to() assumes its frame size is less than page size, which
740 // should always be true if the function is not inlined.
741
742 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
743 #define NOINLINE
744 #else
745 #define NOINLINE __attribute__ ((noinline))
746 #endif
747
748 static void _expand_stack_to(address bottom) NOINLINE;
749
750 static void _expand_stack_to(address bottom) {
751 address sp;
752 size_t size;
753 volatile char *p;
754
755 // Adjust bottom to point to the largest address within the same page, it
756 // gives us a one-page buffer if alloca() allocates slightly more memory.
757 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
758 bottom += os::Linux::page_size() - 1;
759
760 // sp might be slightly above current stack pointer; if that's the case, we
761 // will alloca() a little more space than necessary, which is OK. Don't use
762 // os::current_stack_pointer(), as its result can be slightly below current
763 // stack pointer, causing us to not alloca enough to reach "bottom".
764 sp = (address)&sp;
765
766 if (sp > bottom) {
767 size = sp - bottom;
768 p = (volatile char *)alloca(size);
769 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
770 p[0] = '\0';
771 }
772 }
773
774 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
775 assert(t!=NULL, "just checking");
776 assert(t->osthread()->expanding_stack(), "expand should be set");
777 assert(t->stack_base() != NULL, "stack_base was not initialized");
778
779 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
780 sigset_t mask_all, old_sigset;
781 sigfillset(&mask_all);
782 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
783 _expand_stack_to(addr);
784 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
785 return true;
786 }
787 return false;
788 }
789
790 //////////////////////////////////////////////////////////////////////////////
791 // create new thread
792
793 static address highest_vm_reserved_address();
794
795 // check if it's safe to start a new thread
796 static bool _thread_safety_check(Thread* thread) {
797 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
798 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
799 // Heap is mmap'ed at lower end of memory space. Thread stacks are
800 // allocated (MAP_FIXED) from high address space. Every thread stack
801 // occupies a fixed size slot (usually 2Mbytes, but user can change
802 // it to other values if they rebuild LinuxThreads).
803 //
804 // Problem with MAP_FIXED is that mmap() can still succeed even part of
805 // the memory region has already been mmap'ed. That means if we have too
806 // many threads and/or very large heap, eventually thread stack will
807 // collide with heap.
808 //
809 // Here we try to prevent heap/stack collision by comparing current
810 // stack bottom with the highest address that has been mmap'ed by JVM
811 // plus a safety margin for memory maps created by native code.
812 //
813 // This feature can be disabled by setting ThreadSafetyMargin to 0
814 //
815 if (ThreadSafetyMargin > 0) {
816 address stack_bottom = os::current_stack_base() - os::current_stack_size();
817
818 // not safe if our stack extends below the safety margin
819 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
820 } else {
821 return true;
822 }
823 } else {
824 // Floating stack LinuxThreads or NPTL:
825 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
826 // there's not enough space left, pthread_create() will fail. If we come
827 // here, that means enough space has been reserved for stack.
828 return true;
829 }
830 }
831
832 // Thread start routine for all newly created threads
833 static void *java_start(Thread *thread) {
834 // Try to randomize the cache line index of hot stack frames.
835 // This helps when threads of the same stack traces evict each other's
836 // cache lines. The threads can be either from the same JVM instance, or
837 // from different JVM instances. The benefit is especially true for
838 // processors with hyperthreading technology.
839 static int counter = 0;
840 int pid = os::current_process_id();
841 alloca(((pid ^ counter++) & 7) * 128);
842
843 ThreadLocalStorage::set_thread(thread);
844
845 OSThread* osthread = thread->osthread();
846 Monitor* sync = osthread->startThread_lock();
847
848 // non floating stack LinuxThreads needs extra check, see above
849 if (!_thread_safety_check(thread)) {
850 // notify parent thread
851 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
852 osthread->set_state(ZOMBIE);
853 sync->notify_all();
854 return NULL;
855 }
856
857 // thread_id is kernel thread id (similar to Solaris LWP id)
858 osthread->set_thread_id(os::Linux::gettid());
859
860 if (UseNUMA) {
861 int lgrp_id = os::numa_get_group_id();
862 if (lgrp_id != -1) {
863 thread->set_lgrp_id(lgrp_id);
864 }
865 }
866 // initialize signal mask for this thread
867 os::Linux::hotspot_sigmask(thread);
868
869 // initialize floating point control register
870 os::Linux::init_thread_fpu_state();
871
872 // handshaking with parent thread
873 {
874 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
875
876 // notify parent thread
877 osthread->set_state(INITIALIZED);
878 sync->notify_all();
879
880 // wait until os::start_thread()
881 while (osthread->get_state() == INITIALIZED) {
882 sync->wait(Mutex::_no_safepoint_check_flag);
883 }
884 }
885
886 // call one more level start routine
887 thread->run();
888
889 return 0;
890 }
891
892 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
893 assert(thread->osthread() == NULL, "caller responsible");
894
895 // Allocate the OSThread object
896 OSThread* osthread = new OSThread(NULL, NULL);
897 if (osthread == NULL) {
898 return false;
899 }
900
901 // set the correct thread state
902 osthread->set_thread_type(thr_type);
903
904 // Initial state is ALLOCATED but not INITIALIZED
905 osthread->set_state(ALLOCATED);
906
907 thread->set_osthread(osthread);
908
909 // init thread attributes
910 pthread_attr_t attr;
911 pthread_attr_init(&attr);
912 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
913
914 // stack size
915 if (os::Linux::supports_variable_stack_size()) {
916 // calculate stack size if it's not specified by caller
917 if (stack_size == 0) {
918 stack_size = os::Linux::default_stack_size(thr_type);
919
920 switch (thr_type) {
921 case os::java_thread:
922 // Java threads use ThreadStackSize which default value can be
923 // changed with the flag -Xss
924 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
925 stack_size = JavaThread::stack_size_at_create();
926 break;
927 case os::compiler_thread:
928 if (CompilerThreadStackSize > 0) {
929 stack_size = (size_t)(CompilerThreadStackSize * K);
930 break;
931 } // else fall through:
932 // use VMThreadStackSize if CompilerThreadStackSize is not defined
933 case os::vm_thread:
934 case os::pgc_thread:
935 case os::cgc_thread:
936 case os::watcher_thread:
937 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
938 break;
939 }
940 }
941
942 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
943 pthread_attr_setstacksize(&attr, stack_size);
944 } else {
945 // let pthread_create() pick the default value.
946 }
947
948 // glibc guard page
949 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
950
951 ThreadState state;
952
953 {
954 // Serialize thread creation if we are running with fixed stack LinuxThreads
955 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
956 if (lock) {
957 os::Linux::createThread_lock()->lock_without_safepoint_check();
958 }
959
960 pthread_t tid;
961 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
962
963 pthread_attr_destroy(&attr);
964
965 if (ret != 0) {
966 if (PrintMiscellaneous && (Verbose || WizardMode)) {
967 perror("pthread_create()");
968 }
969 // Need to clean up stuff we've allocated so far
970 thread->set_osthread(NULL);
971 delete osthread;
972 if (lock) os::Linux::createThread_lock()->unlock();
973 return false;
974 }
975
976 // Store pthread info into the OSThread
977 osthread->set_pthread_id(tid);
978
979 // Wait until child thread is either initialized or aborted
980 {
981 Monitor* sync_with_child = osthread->startThread_lock();
982 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
983 while ((state = osthread->get_state()) == ALLOCATED) {
984 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
985 }
986 }
987
988 if (lock) {
989 os::Linux::createThread_lock()->unlock();
990 }
991 }
992
993 // Aborted due to thread limit being reached
994 if (state == ZOMBIE) {
995 thread->set_osthread(NULL);
996 delete osthread;
997 return false;
998 }
999
1000 // The thread is returned suspended (in state INITIALIZED),
1001 // and is started higher up in the call chain
1002 assert(state == INITIALIZED, "race condition");
1003 return true;
1004 }
1005
1006 /////////////////////////////////////////////////////////////////////////////
1007 // attach existing thread
1008
1009 // bootstrap the main thread
1010 bool os::create_main_thread(JavaThread* thread) {
1011 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
1012 return create_attached_thread(thread);
1013 }
1014
1015 bool os::create_attached_thread(JavaThread* thread) {
1016 #ifdef ASSERT
1017 thread->verify_not_published();
1018 #endif
1019
1020 // Allocate the OSThread object
1021 OSThread* osthread = new OSThread(NULL, NULL);
1022
1023 if (osthread == NULL) {
1024 return false;
1025 }
1026
1027 // Store pthread info into the OSThread
1028 osthread->set_thread_id(os::Linux::gettid());
1029 osthread->set_pthread_id(::pthread_self());
1030
1031 // initialize floating point control register
1032 os::Linux::init_thread_fpu_state();
1033
1034 // Initial thread state is RUNNABLE
1035 osthread->set_state(RUNNABLE);
1036
1037 thread->set_osthread(osthread);
1038
1039 if (UseNUMA) {
1040 int lgrp_id = os::numa_get_group_id();
1041 if (lgrp_id != -1) {
1042 thread->set_lgrp_id(lgrp_id);
1043 }
1044 }
1045
1046 if (os::Linux::is_initial_thread()) {
1047 // If current thread is initial thread, its stack is mapped on demand,
1048 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1049 // the entire stack region to avoid SEGV in stack banging.
1050 // It is also useful to get around the heap-stack-gap problem on SuSE
1051 // kernel (see 4821821 for details). We first expand stack to the top
1052 // of yellow zone, then enable stack yellow zone (order is significant,
1053 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1054 // is no gap between the last two virtual memory regions.
1055
1056 JavaThread *jt = (JavaThread *)thread;
1057 address addr = jt->stack_yellow_zone_base();
1058 assert(addr != NULL, "initialization problem?");
1059 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1060
1061 osthread->set_expanding_stack();
1062 os::Linux::manually_expand_stack(jt, addr);
1063 osthread->clear_expanding_stack();
1064 }
1065
1066 // initialize signal mask for this thread
1067 // and save the caller's signal mask
1068 os::Linux::hotspot_sigmask(thread);
1069
1070 return true;
1071 }
1072
1073 void os::pd_start_thread(Thread* thread) {
1074 OSThread * osthread = thread->osthread();
1075 assert(osthread->get_state() != INITIALIZED, "just checking");
1076 Monitor* sync_with_child = osthread->startThread_lock();
1077 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1078 sync_with_child->notify();
1079 }
1080
1081 // Free Linux resources related to the OSThread
1082 void os::free_thread(OSThread* osthread) {
1083 assert(osthread != NULL, "osthread not set");
1084
1085 if (Thread::current()->osthread() == osthread) {
1086 // Restore caller's signal mask
1087 sigset_t sigmask = osthread->caller_sigmask();
1088 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1089 }
1090
1091 delete osthread;
1092 }
1093
1094 //////////////////////////////////////////////////////////////////////////////
1095 // thread local storage
1096
1097 int os::allocate_thread_local_storage() {
1098 pthread_key_t key;
1099 int rslt = pthread_key_create(&key, NULL);
1100 assert(rslt == 0, "cannot allocate thread local storage");
1101 return (int)key;
1102 }
1103
1104 // Note: This is currently not used by VM, as we don't destroy TLS key
1105 // on VM exit.
1106 void os::free_thread_local_storage(int index) {
1107 int rslt = pthread_key_delete((pthread_key_t)index);
1108 assert(rslt == 0, "invalid index");
1109 }
1110
1111 void os::thread_local_storage_at_put(int index, void* value) {
1112 int rslt = pthread_setspecific((pthread_key_t)index, value);
1113 assert(rslt == 0, "pthread_setspecific failed");
1114 }
1115
1116 extern "C" Thread* get_thread() {
1117 return ThreadLocalStorage::thread();
1118 }
1119
1120 //////////////////////////////////////////////////////////////////////////////
1121 // initial thread
1122
1123 // Check if current thread is the initial thread, similar to Solaris thr_main.
1124 bool os::Linux::is_initial_thread(void) {
1125 char dummy;
1126 // If called before init complete, thread stack bottom will be null.
1127 // Can be called if fatal error occurs before initialization.
1128 if (initial_thread_stack_bottom() == NULL) return false;
1129 assert(initial_thread_stack_bottom() != NULL &&
1130 initial_thread_stack_size() != 0,
1131 "os::init did not locate initial thread's stack region");
1132 if ((address)&dummy >= initial_thread_stack_bottom() &&
1133 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1134 return true;
1135 else return false;
1136 }
1137
1138 // Find the virtual memory area that contains addr
1139 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1140 FILE *fp = fopen("/proc/self/maps", "r");
1141 if (fp) {
1142 address low, high;
1143 while (!feof(fp)) {
1144 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1145 if (low <= addr && addr < high) {
1146 if (vma_low) *vma_low = low;
1147 if (vma_high) *vma_high = high;
1148 fclose (fp);
1149 return true;
1150 }
1151 }
1152 for (;;) {
1153 int ch = fgetc(fp);
1154 if (ch == EOF || ch == (int)'\n') break;
1155 }
1156 }
1157 fclose(fp);
1158 }
1159 return false;
1160 }
1161
1162 // Locate initial thread stack. This special handling of initial thread stack
1163 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1164 // bogus value for initial thread.
1165 void os::Linux::capture_initial_stack(size_t max_size) {
1166 // stack size is the easy part, get it from RLIMIT_STACK
1167 size_t stack_size;
1168 struct rlimit rlim;
1169 getrlimit(RLIMIT_STACK, &rlim);
1170 stack_size = rlim.rlim_cur;
1171
1172 // 6308388: a bug in ld.so will relocate its own .data section to the
1173 // lower end of primordial stack; reduce ulimit -s value a little bit
1174 // so we won't install guard page on ld.so's data section.
1175 stack_size -= 2 * page_size();
1176
1177 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1178 // 7.1, in both cases we will get 2G in return value.
1179 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1180 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1181 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1182 // in case other parts in glibc still assumes 2M max stack size.
1183 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1184 #ifndef IA64
1185 if (stack_size > 2 * K * K) stack_size = 2 * K * K;
1186 #else
1187 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1188 if (stack_size > 4 * K * K) stack_size = 4 * K * K;
1189 #endif
1190
1191 // Try to figure out where the stack base (top) is. This is harder.
1192 //
1193 // When an application is started, glibc saves the initial stack pointer in
1194 // a global variable "__libc_stack_end", which is then used by system
1195 // libraries. __libc_stack_end should be pretty close to stack top. The
1196 // variable is available since the very early days. However, because it is
1197 // a private interface, it could disappear in the future.
1198 //
1199 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1200 // to __libc_stack_end, it is very close to stack top, but isn't the real
1201 // stack top. Note that /proc may not exist if VM is running as a chroot
1202 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1203 // /proc/<pid>/stat could change in the future (though unlikely).
1204 //
1205 // We try __libc_stack_end first. If that doesn't work, look for
1206 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1207 // as a hint, which should work well in most cases.
1208
1209 uintptr_t stack_start;
1210
1211 // try __libc_stack_end first
1212 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1213 if (p && *p) {
1214 stack_start = *p;
1215 } else {
1216 // see if we can get the start_stack field from /proc/self/stat
1217 FILE *fp;
1218 int pid;
1219 char state;
1220 int ppid;
1221 int pgrp;
1222 int session;
1223 int nr;
1224 int tpgrp;
1225 unsigned long flags;
1226 unsigned long minflt;
1227 unsigned long cminflt;
1228 unsigned long majflt;
1229 unsigned long cmajflt;
1230 unsigned long utime;
1231 unsigned long stime;
1232 long cutime;
1233 long cstime;
1234 long prio;
1235 long nice;
1236 long junk;
1237 long it_real;
1238 uintptr_t start;
1239 uintptr_t vsize;
1240 intptr_t rss;
1241 uintptr_t rsslim;
1242 uintptr_t scodes;
1243 uintptr_t ecode;
1244 int i;
1245
1246 // Figure what the primordial thread stack base is. Code is inspired
1247 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1248 // followed by command name surrounded by parentheses, state, etc.
1249 char stat[2048];
1250 int statlen;
1251
1252 fp = fopen("/proc/self/stat", "r");
1253 if (fp) {
1254 statlen = fread(stat, 1, 2047, fp);
1255 stat[statlen] = '\0';
1256 fclose(fp);
1257
1258 // Skip pid and the command string. Note that we could be dealing with
1259 // weird command names, e.g. user could decide to rename java launcher
1260 // to "java 1.4.2 :)", then the stat file would look like
1261 // 1234 (java 1.4.2 :)) R ... ...
1262 // We don't really need to know the command string, just find the last
1263 // occurrence of ")" and then start parsing from there. See bug 4726580.
1264 char * s = strrchr(stat, ')');
1265
1266 i = 0;
1267 if (s) {
1268 // Skip blank chars
1269 do s++; while (isspace(*s));
1270
1271 #define _UFM UINTX_FORMAT
1272 #define _DFM INTX_FORMAT
1273
1274 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1275 /* 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 */
1276 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,
1277 &state, /* 3 %c */
1278 &ppid, /* 4 %d */
1279 &pgrp, /* 5 %d */
1280 &session, /* 6 %d */
1281 &nr, /* 7 %d */
1282 &tpgrp, /* 8 %d */
1283 &flags, /* 9 %lu */
1284 &minflt, /* 10 %lu */
1285 &cminflt, /* 11 %lu */
1286 &majflt, /* 12 %lu */
1287 &cmajflt, /* 13 %lu */
1288 &utime, /* 14 %lu */
1289 &stime, /* 15 %lu */
1290 &cutime, /* 16 %ld */
1291 &cstime, /* 17 %ld */
1292 &prio, /* 18 %ld */
1293 &nice, /* 19 %ld */
1294 &junk, /* 20 %ld */
1295 &it_real, /* 21 %ld */
1296 &start, /* 22 UINTX_FORMAT */
1297 &vsize, /* 23 UINTX_FORMAT */
1298 &rss, /* 24 INTX_FORMAT */
1299 &rsslim, /* 25 UINTX_FORMAT */
1300 &scodes, /* 26 UINTX_FORMAT */
1301 &ecode, /* 27 UINTX_FORMAT */
1302 &stack_start); /* 28 UINTX_FORMAT */
1303 }
1304
1305 #undef _UFM
1306 #undef _DFM
1307
1308 if (i != 28 - 2) {
1309 assert(false, "Bad conversion from /proc/self/stat");
1310 // product mode - assume we are the initial thread, good luck in the
1311 // embedded case.
1312 warning("Can't detect initial thread stack location - bad conversion");
1313 stack_start = (uintptr_t) &rlim;
1314 }
1315 } else {
1316 // For some reason we can't open /proc/self/stat (for example, running on
1317 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1318 // most cases, so don't abort:
1319 warning("Can't detect initial thread stack location - no /proc/self/stat");
1320 stack_start = (uintptr_t) &rlim;
1321 }
1322 }
1323
1324 // Now we have a pointer (stack_start) very close to the stack top, the
1325 // next thing to do is to figure out the exact location of stack top. We
1326 // can find out the virtual memory area that contains stack_start by
1327 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1328 // and its upper limit is the real stack top. (again, this would fail if
1329 // running inside chroot, because /proc may not exist.)
1330
1331 uintptr_t stack_top;
1332 address low, high;
1333 if (find_vma((address)stack_start, &low, &high)) {
1334 // success, "high" is the true stack top. (ignore "low", because initial
1335 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1336 stack_top = (uintptr_t)high;
1337 } else {
1338 // failed, likely because /proc/self/maps does not exist
1339 warning("Can't detect initial thread stack location - find_vma failed");
1340 // best effort: stack_start is normally within a few pages below the real
1341 // stack top, use it as stack top, and reduce stack size so we won't put
1342 // guard page outside stack.
1343 stack_top = stack_start;
1344 stack_size -= 16 * page_size();
1345 }
1346
1347 // stack_top could be partially down the page so align it
1348 stack_top = align_size_up(stack_top, page_size());
1349
1350 if (max_size && stack_size > max_size) {
1351 _initial_thread_stack_size = max_size;
1352 } else {
1353 _initial_thread_stack_size = stack_size;
1354 }
1355
1356 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1357 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1358 }
1359
1360 ////////////////////////////////////////////////////////////////////////////////
1361 // time support
1362
1363 // Time since start-up in seconds to a fine granularity.
1364 // Used by VMSelfDestructTimer and the MemProfiler.
1365 double os::elapsedTime() {
1366
1367 return (double)(os::elapsed_counter()) * 0.000001;
1368 }
1369
1370 jlong os::elapsed_counter() {
1371 timeval time;
1372 int status = gettimeofday(&time, NULL);
1373 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1374 }
1375
1376 jlong os::elapsed_frequency() {
1377 return (1000 * 1000);
1378 }
1379
1380 // For now, we say that linux does not support vtime. I have no idea
1381 // whether it can actually be made to (DLD, 9/13/05).
1382
1383 bool os::supports_vtime() { return false; }
1384 bool os::enable_vtime() { return false; }
1385 bool os::vtime_enabled() { return false; }
1386 double os::elapsedVTime() {
1387 // better than nothing, but not much
1388 return elapsedTime();
1389 }
1390
1391 jlong os::javaTimeMillis() {
1392 timeval time;
1393 int status = gettimeofday(&time, NULL);
1394 assert(status != -1, "linux error");
1395 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1396 }
1397
1398 #ifndef CLOCK_MONOTONIC
1399 #define CLOCK_MONOTONIC (1)
1400 #endif
1401
1402 void os::Linux::clock_init() {
1403 // we do dlopen's in this particular order due to bug in linux
1404 // dynamical loader (see 6348968) leading to crash on exit
1405 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1406 if (handle == NULL) {
1407 handle = dlopen("librt.so", RTLD_LAZY);
1408 }
1409
1410 if (handle) {
1411 int (*clock_getres_func)(clockid_t, struct timespec*) =
1412 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1413 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1414 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1415 if (clock_getres_func && clock_gettime_func) {
1416 // See if monotonic clock is supported by the kernel. Note that some
1417 // early implementations simply return kernel jiffies (updated every
1418 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1419 // for nano time (though the monotonic property is still nice to have).
1420 // It's fixed in newer kernels, however clock_getres() still returns
1421 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1422 // resolution for now. Hopefully as people move to new kernels, this
1423 // won't be a problem.
1424 struct timespec res;
1425 struct timespec tp;
1426 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1427 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1428 // yes, monotonic clock is supported
1429 _clock_gettime = clock_gettime_func;
1430 } else {
1431 // close librt if there is no monotonic clock
1432 dlclose(handle);
1433 }
1434 }
1435 }
1436 }
1437
1438 #ifndef SYS_clock_getres
1439
1440 #if defined(IA32) || defined(AMD64)
1441 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1442 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1443 #else
1444 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1445 #define sys_clock_getres(x,y) -1
1446 #endif
1447
1448 #else
1449 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1450 #endif
1451
1452 void os::Linux::fast_thread_clock_init() {
1453 if (!UseLinuxPosixThreadCPUClocks) {
1454 return;
1455 }
1456 clockid_t clockid;
1457 struct timespec tp;
1458 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1459 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1460
1461 // Switch to using fast clocks for thread cpu time if
1462 // the sys_clock_getres() returns 0 error code.
1463 // Note, that some kernels may support the current thread
1464 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1465 // returned by the pthread_getcpuclockid().
1466 // If the fast Posix clocks are supported then the sys_clock_getres()
1467 // must return at least tp.tv_sec == 0 which means a resolution
1468 // better than 1 sec. This is extra check for reliability.
1469
1470 if(pthread_getcpuclockid_func &&
1471 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1472 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1473
1474 _supports_fast_thread_cpu_time = true;
1475 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1476 }
1477 }
1478
1479 jlong os::javaTimeNanos() {
1480 if (Linux::supports_monotonic_clock()) {
1481 struct timespec tp;
1482 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1483 assert(status == 0, "gettime error");
1484 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1485 return result;
1486 } else {
1487 timeval time;
1488 int status = gettimeofday(&time, NULL);
1489 assert(status != -1, "linux error");
1490 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1491 return 1000 * usecs;
1492 }
1493 }
1494
1495 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1496 if (Linux::supports_monotonic_clock()) {
1497 info_ptr->max_value = ALL_64_BITS;
1498
1499 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1500 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1501 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1502 } else {
1503 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1504 info_ptr->max_value = ALL_64_BITS;
1505
1506 // gettimeofday is a real time clock so it skips
1507 info_ptr->may_skip_backward = true;
1508 info_ptr->may_skip_forward = true;
1509 }
1510
1511 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1512 }
1513
1514 // Return the real, user, and system times in seconds from an
1515 // arbitrary fixed point in the past.
1516 bool os::getTimesSecs(double* process_real_time,
1517 double* process_user_time,
1518 double* process_system_time) {
1519 struct tms ticks;
1520 clock_t real_ticks = times(&ticks);
1521
1522 if (real_ticks == (clock_t) (-1)) {
1523 return false;
1524 } else {
1525 double ticks_per_second = (double) clock_tics_per_sec;
1526 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1527 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1528 *process_real_time = ((double) real_ticks) / ticks_per_second;
1529
1530 return true;
1531 }
1532 }
1533
1534
1535 char * os::local_time_string(char *buf, size_t buflen) {
1536 struct tm t;
1537 time_t long_time;
1538 time(&long_time);
1539 localtime_r(&long_time, &t);
1540 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1541 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1542 t.tm_hour, t.tm_min, t.tm_sec);
1543 return buf;
1544 }
1545
1546 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1547 return localtime_r(clock, res);
1548 }
1549
1550 ////////////////////////////////////////////////////////////////////////////////
1551 // runtime exit support
1552
1553 // Note: os::shutdown() might be called very early during initialization, or
1554 // called from signal handler. Before adding something to os::shutdown(), make
1555 // sure it is async-safe and can handle partially initialized VM.
1556 void os::shutdown() {
1557
1558 // allow PerfMemory to attempt cleanup of any persistent resources
1559 perfMemory_exit();
1560
1561 // needs to remove object in file system
1562 AttachListener::abort();
1563
1564 // flush buffered output, finish log files
1565 ostream_abort();
1566
1567 // Check for abort hook
1568 abort_hook_t abort_hook = Arguments::abort_hook();
1569 if (abort_hook != NULL) {
1570 abort_hook();
1571 }
1572
1573 }
1574
1575 // Note: os::abort() might be called very early during initialization, or
1576 // called from signal handler. Before adding something to os::abort(), make
1577 // sure it is async-safe and can handle partially initialized VM.
1578 void os::abort(bool dump_core) {
1579 os::shutdown();
1580 if (dump_core) {
1581 #ifndef PRODUCT
1582 fdStream out(defaultStream::output_fd());
1583 out.print_raw("Current thread is ");
1584 char buf[16];
1585 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1586 out.print_raw_cr(buf);
1587 out.print_raw_cr("Dumping core ...");
1588 #endif
1589 ::abort(); // dump core
1590 }
1591
1592 ::exit(1);
1593 }
1594
1595 // Die immediately, no exit hook, no abort hook, no cleanup.
1596 void os::die() {
1597 // _exit() on LinuxThreads only kills current thread
1598 ::abort();
1599 }
1600
1601 // unused on linux for now.
1602 void os::set_error_file(const char *logfile) {}
1603
1604
1605 // This method is a copy of JDK's sysGetLastErrorString
1606 // from src/solaris/hpi/src/system_md.c
1607
1608 size_t os::lasterror(char *buf, size_t len) {
1609
1610 if (errno == 0) return 0;
1611
1612 const char *s = ::strerror(errno);
1613 size_t n = ::strlen(s);
1614 if (n >= len) {
1615 n = len - 1;
1616 }
1617 ::strncpy(buf, s, n);
1618 buf[n] = '\0';
1619 return n;
1620 }
1621
1622 intx os::current_thread_id() { return (intx)pthread_self(); }
1623 int os::current_process_id() {
1624
1625 // Under the old linux thread library, linux gives each thread
1626 // its own process id. Because of this each thread will return
1627 // a different pid if this method were to return the result
1628 // of getpid(2). Linux provides no api that returns the pid
1629 // of the launcher thread for the vm. This implementation
1630 // returns a unique pid, the pid of the launcher thread
1631 // that starts the vm 'process'.
1632
1633 // Under the NPTL, getpid() returns the same pid as the
1634 // launcher thread rather than a unique pid per thread.
1635 // Use gettid() if you want the old pre NPTL behaviour.
1636
1637 // if you are looking for the result of a call to getpid() that
1638 // returns a unique pid for the calling thread, then look at the
1639 // OSThread::thread_id() method in osThread_linux.hpp file
1640
1641 return (int)(_initial_pid ? _initial_pid : getpid());
1642 }
1643
1644 // DLL functions
1645
1646 const char* os::dll_file_extension() { return ".so"; }
1647
1648 // This must be hard coded because it's the system's temporary
1649 // directory not the java application's temp directory, ala java.io.tmpdir.
1650 const char* os::get_temp_directory() { return "/tmp"; }
1651
1652 static bool file_exists(const char* filename) {
1653 struct stat statbuf;
1654 if (filename == NULL || strlen(filename) == 0) {
1655 return false;
1656 }
1657 return os::stat(filename, &statbuf) == 0;
1658 }
1659
1660 void os::dll_build_name(char* buffer, size_t buflen,
1661 const char* pname, const char* fname) {
1662 // Copied from libhpi
1663 const size_t pnamelen = pname ? strlen(pname) : 0;
1664
1665 // Quietly truncate on buffer overflow. Should be an error.
1666 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1667 *buffer = '\0';
1668 return;
1669 }
1670
1671 if (pnamelen == 0) {
1672 snprintf(buffer, buflen, "lib%s.so", fname);
1673 } else if (strchr(pname, *os::path_separator()) != NULL) {
1674 int n;
1675 char** pelements = split_path(pname, &n);
1676 for (int i = 0 ; i < n ; i++) {
1677 // Really shouldn't be NULL, but check can't hurt
1678 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1679 continue; // skip the empty path values
1680 }
1681 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1682 if (file_exists(buffer)) {
1683 break;
1684 }
1685 }
1686 // release the storage
1687 for (int i = 0 ; i < n ; i++) {
1688 if (pelements[i] != NULL) {
1689 FREE_C_HEAP_ARRAY(char, pelements[i]);
1690 }
1691 }
1692 if (pelements != NULL) {
1693 FREE_C_HEAP_ARRAY(char*, pelements);
1694 }
1695 } else {
1696 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1697 }
1698 }
1699
1700 const char* os::get_current_directory(char *buf, int buflen) {
1701 return getcwd(buf, buflen);
1702 }
1703
1704 // check if addr is inside libjvm[_g].so
1705 bool os::address_is_in_vm(address addr) {
1706 static address libjvm_base_addr;
1707 Dl_info dlinfo;
1708
1709 if (libjvm_base_addr == NULL) {
1710 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
1711 libjvm_base_addr = (address)dlinfo.dli_fbase;
1712 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1713 }
1714
1715 if (dladdr((void *)addr, &dlinfo)) {
1716 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1717 }
1718
1719 return false;
1720 }
1721
1722 bool os::dll_address_to_function_name(address addr, char *buf,
1723 int buflen, int *offset) {
1724 Dl_info dlinfo;
1725
1726 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
1727 if (buf != NULL) {
1728 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1729 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1730 }
1731 }
1732 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1733 return true;
1734 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) {
1735 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1736 dlinfo.dli_fname, buf, buflen, offset) == Decoder::no_error) {
1737 return true;
1738 }
1739 }
1740
1741 if (buf != NULL) buf[0] = '\0';
1742 if (offset != NULL) *offset = -1;
1743 return false;
1744 }
1745
1746 struct _address_to_library_name {
1747 address addr; // input : memory address
1748 size_t buflen; // size of fname
1749 char* fname; // output: library name
1750 address base; // library base addr
1751 };
1752
1753 static int address_to_library_name_callback(struct dl_phdr_info *info,
1754 size_t size, void *data) {
1755 int i;
1756 bool found = false;
1757 address libbase = NULL;
1758 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1759
1760 // iterate through all loadable segments
1761 for (i = 0; i < info->dlpi_phnum; i++) {
1762 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1763 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1764 // base address of a library is the lowest address of its loaded
1765 // segments.
1766 if (libbase == NULL || libbase > segbase) {
1767 libbase = segbase;
1768 }
1769 // see if 'addr' is within current segment
1770 if (segbase <= d->addr &&
1771 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1772 found = true;
1773 }
1774 }
1775 }
1776
1777 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1778 // so dll_address_to_library_name() can fall through to use dladdr() which
1779 // can figure out executable name from argv[0].
1780 if (found && info->dlpi_name && info->dlpi_name[0]) {
1781 d->base = libbase;
1782 if (d->fname) {
1783 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1784 }
1785 return 1;
1786 }
1787 return 0;
1788 }
1789
1790 bool os::dll_address_to_library_name(address addr, char* buf,
1791 int buflen, int* offset) {
1792 Dl_info dlinfo;
1793 struct _address_to_library_name data;
1794
1795 // There is a bug in old glibc dladdr() implementation that it could resolve
1796 // to wrong library name if the .so file has a base address != NULL. Here
1797 // we iterate through the program headers of all loaded libraries to find
1798 // out which library 'addr' really belongs to. This workaround can be
1799 // removed once the minimum requirement for glibc is moved to 2.3.x.
1800 data.addr = addr;
1801 data.fname = buf;
1802 data.buflen = buflen;
1803 data.base = NULL;
1804 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1805
1806 if (rslt) {
1807 // buf already contains library name
1808 if (offset) *offset = addr - data.base;
1809 return true;
1810 } else if (dladdr((void*)addr, &dlinfo)){
1811 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1812 if (offset) *offset = addr - (address)dlinfo.dli_fbase;
1813 return true;
1814 } else {
1815 if (buf) buf[0] = '\0';
1816 if (offset) *offset = -1;
1817 return false;
1818 }
1819 }
1820
1821 // Loads .dll/.so and
1822 // in case of error it checks if .dll/.so was built for the
1823 // same architecture as Hotspot is running on
1824
1825 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1826 {
1827 void * result= ::dlopen(filename, RTLD_LAZY);
1828 if (result != NULL) {
1829 // Successful loading
1830 return result;
1831 }
1832
1833 Elf32_Ehdr elf_head;
1834
1835 // Read system error message into ebuf
1836 // It may or may not be overwritten below
1837 ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1838 ebuf[ebuflen-1]='\0';
1839 int diag_msg_max_length=ebuflen-strlen(ebuf);
1840 char* diag_msg_buf=ebuf+strlen(ebuf);
1841
1842 if (diag_msg_max_length==0) {
1843 // No more space in ebuf for additional diagnostics message
1844 return NULL;
1845 }
1846
1847
1848 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1849
1850 if (file_descriptor < 0) {
1851 // Can't open library, report dlerror() message
1852 return NULL;
1853 }
1854
1855 bool failed_to_read_elf_head=
1856 (sizeof(elf_head)!=
1857 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1858
1859 ::close(file_descriptor);
1860 if (failed_to_read_elf_head) {
1861 // file i/o error - report dlerror() msg
1862 return NULL;
1863 }
1864
1865 typedef struct {
1866 Elf32_Half code; // Actual value as defined in elf.h
1867 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1868 char elf_class; // 32 or 64 bit
1869 char endianess; // MSB or LSB
1870 char* name; // String representation
1871 } arch_t;
1872
1873 #ifndef EM_486
1874 #define EM_486 6 /* Intel 80486 */
1875 #endif
1876
1877 static const arch_t arch_array[]={
1878 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1879 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1880 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1881 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1882 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1883 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1884 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1885 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1886 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1887 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1888 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1889 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1890 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1891 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1892 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1893 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1894 };
1895
1896 #if (defined IA32)
1897 static Elf32_Half running_arch_code=EM_386;
1898 #elif (defined AMD64)
1899 static Elf32_Half running_arch_code=EM_X86_64;
1900 #elif (defined IA64)
1901 static Elf32_Half running_arch_code=EM_IA_64;
1902 #elif (defined __sparc) && (defined _LP64)
1903 static Elf32_Half running_arch_code=EM_SPARCV9;
1904 #elif (defined __sparc) && (!defined _LP64)
1905 static Elf32_Half running_arch_code=EM_SPARC;
1906 #elif (defined __powerpc64__)
1907 static Elf32_Half running_arch_code=EM_PPC64;
1908 #elif (defined __powerpc__)
1909 static Elf32_Half running_arch_code=EM_PPC;
1910 #elif (defined ARM)
1911 static Elf32_Half running_arch_code=EM_ARM;
1912 #elif (defined S390)
1913 static Elf32_Half running_arch_code=EM_S390;
1914 #elif (defined ALPHA)
1915 static Elf32_Half running_arch_code=EM_ALPHA;
1916 #elif (defined MIPSEL)
1917 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1918 #elif (defined PARISC)
1919 static Elf32_Half running_arch_code=EM_PARISC;
1920 #elif (defined MIPS)
1921 static Elf32_Half running_arch_code=EM_MIPS;
1922 #elif (defined M68K)
1923 static Elf32_Half running_arch_code=EM_68K;
1924 #else
1925 #error Method os::dll_load requires that one of following is defined:\
1926 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1927 #endif
1928
1929 // Identify compatability class for VM's architecture and library's architecture
1930 // Obtain string descriptions for architectures
1931
1932 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1933 int running_arch_index=-1;
1934
1935 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1936 if (running_arch_code == arch_array[i].code) {
1937 running_arch_index = i;
1938 }
1939 if (lib_arch.code == arch_array[i].code) {
1940 lib_arch.compat_class = arch_array[i].compat_class;
1941 lib_arch.name = arch_array[i].name;
1942 }
1943 }
1944
1945 assert(running_arch_index != -1,
1946 "Didn't find running architecture code (running_arch_code) in arch_array");
1947 if (running_arch_index == -1) {
1948 // Even though running architecture detection failed
1949 // we may still continue with reporting dlerror() message
1950 return NULL;
1951 }
1952
1953 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1954 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1955 return NULL;
1956 }
1957
1958 #ifndef S390
1959 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1960 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1961 return NULL;
1962 }
1963 #endif // !S390
1964
1965 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1966 if ( lib_arch.name!=NULL ) {
1967 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1968 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1969 lib_arch.name, arch_array[running_arch_index].name);
1970 } else {
1971 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1972 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1973 lib_arch.code,
1974 arch_array[running_arch_index].name);
1975 }
1976 }
1977
1978 return NULL;
1979 }
1980
1981 /*
1982 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
1983 * chances are you might want to run the generated bits against glibc-2.0
1984 * libdl.so, so always use locking for any version of glibc.
1985 */
1986 void* os::dll_lookup(void* handle, const char* name) {
1987 pthread_mutex_lock(&dl_mutex);
1988 void* res = dlsym(handle, name);
1989 pthread_mutex_unlock(&dl_mutex);
1990 return res;
1991 }
1992
1993
1994 static bool _print_ascii_file(const char* filename, outputStream* st) {
1995 int fd = ::open(filename, O_RDONLY);
1996 if (fd == -1) {
1997 return false;
1998 }
1999
2000 char buf[32];
2001 int bytes;
2002 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2003 st->print_raw(buf, bytes);
2004 }
2005
2006 ::close(fd);
2007
2008 return true;
2009 }
2010
2011 void os::print_dll_info(outputStream *st) {
2012 st->print_cr("Dynamic libraries:");
2013
2014 char fname[32];
2015 pid_t pid = os::Linux::gettid();
2016
2017 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2018
2019 if (!_print_ascii_file(fname, st)) {
2020 st->print("Can not get library information for pid = %d\n", pid);
2021 }
2022 }
2023
2024
2025 void os::print_os_info(outputStream* st) {
2026 st->print("OS:");
2027
2028 // Try to identify popular distros.
2029 // Most Linux distributions have /etc/XXX-release file, which contains
2030 // the OS version string. Some have more than one /etc/XXX-release file
2031 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
2032 // so the order is important.
2033 if (!_print_ascii_file("/etc/mandrake-release", st) &&
2034 !_print_ascii_file("/etc/sun-release", st) &&
2035 !_print_ascii_file("/etc/redhat-release", st) &&
2036 !_print_ascii_file("/etc/SuSE-release", st) &&
2037 !_print_ascii_file("/etc/turbolinux-release", st) &&
2038 !_print_ascii_file("/etc/gentoo-release", st) &&
2039 !_print_ascii_file("/etc/debian_version", st) &&
2040 !_print_ascii_file("/etc/ltib-release", st) &&
2041 !_print_ascii_file("/etc/angstrom-version", st)) {
2042 st->print("Linux");
2043 }
2044 st->cr();
2045
2046 // kernel
2047 st->print("uname:");
2048 struct utsname name;
2049 uname(&name);
2050 st->print(name.sysname); st->print(" ");
2051 st->print(name.release); st->print(" ");
2052 st->print(name.version); st->print(" ");
2053 st->print(name.machine);
2054 st->cr();
2055
2056 // Print warning if unsafe chroot environment detected
2057 if (unsafe_chroot_detected) {
2058 st->print("WARNING!! ");
2059 st->print_cr(unstable_chroot_error);
2060 }
2061
2062 // libc, pthread
2063 st->print("libc:");
2064 st->print(os::Linux::glibc_version()); st->print(" ");
2065 st->print(os::Linux::libpthread_version()); st->print(" ");
2066 if (os::Linux::is_LinuxThreads()) {
2067 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2068 }
2069 st->cr();
2070
2071 // rlimit
2072 st->print("rlimit:");
2073 struct rlimit rlim;
2074
2075 st->print(" STACK ");
2076 getrlimit(RLIMIT_STACK, &rlim);
2077 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2078 else st->print("%uk", rlim.rlim_cur >> 10);
2079
2080 st->print(", CORE ");
2081 getrlimit(RLIMIT_CORE, &rlim);
2082 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2083 else st->print("%uk", rlim.rlim_cur >> 10);
2084
2085 st->print(", NPROC ");
2086 getrlimit(RLIMIT_NPROC, &rlim);
2087 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2088 else st->print("%d", rlim.rlim_cur);
2089
2090 st->print(", NOFILE ");
2091 getrlimit(RLIMIT_NOFILE, &rlim);
2092 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2093 else st->print("%d", rlim.rlim_cur);
2094
2095 st->print(", AS ");
2096 getrlimit(RLIMIT_AS, &rlim);
2097 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
2098 else st->print("%uk", rlim.rlim_cur >> 10);
2099 st->cr();
2100
2101 // load average
2102 st->print("load average:");
2103 double loadavg[3];
2104 os::loadavg(loadavg, 3);
2105 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
2106 st->cr();
2107
2108 // meminfo
2109 st->print("\n/proc/meminfo:\n");
2110 _print_ascii_file("/proc/meminfo", st);
2111 st->cr();
2112 }
2113
2114 void os::pd_print_cpu_info(outputStream* st) {
2115 st->print("\n/proc/cpuinfo:\n");
2116 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2117 st->print(" <Not Available>");
2118 }
2119 st->cr();
2120 }
2121
2122 void os::print_memory_info(outputStream* st) {
2123
2124 st->print("Memory:");
2125 st->print(" %dk page", os::vm_page_size()>>10);
2126
2127 // values in struct sysinfo are "unsigned long"
2128 struct sysinfo si;
2129 sysinfo(&si);
2130
2131 st->print(", physical " UINT64_FORMAT "k",
2132 os::physical_memory() >> 10);
2133 st->print("(" UINT64_FORMAT "k free)",
2134 os::available_memory() >> 10);
2135 st->print(", swap " UINT64_FORMAT "k",
2136 ((jlong)si.totalswap * si.mem_unit) >> 10);
2137 st->print("(" UINT64_FORMAT "k free)",
2138 ((jlong)si.freeswap * si.mem_unit) >> 10);
2139 st->cr();
2140 }
2141
2142 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
2143 // but they're the same for all the linux arch that we support
2144 // and they're the same for solaris but there's no common place to put this.
2145 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
2146 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
2147 "ILL_COPROC", "ILL_BADSTK" };
2148
2149 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
2150 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
2151 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
2152
2153 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
2154
2155 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
2156
2157 void os::print_siginfo(outputStream* st, void* siginfo) {
2158 st->print("siginfo:");
2159
2160 const int buflen = 100;
2161 char buf[buflen];
2162 siginfo_t *si = (siginfo_t*)siginfo;
2163 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
2164 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
2165 st->print("si_errno=%s", buf);
2166 } else {
2167 st->print("si_errno=%d", si->si_errno);
2168 }
2169 const int c = si->si_code;
2170 assert(c > 0, "unexpected si_code");
2171 switch (si->si_signo) {
2172 case SIGILL:
2173 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
2174 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2175 break;
2176 case SIGFPE:
2177 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
2178 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2179 break;
2180 case SIGSEGV:
2181 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2182 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2183 break;
2184 case SIGBUS:
2185 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2186 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2187 break;
2188 default:
2189 st->print(", si_code=%d", si->si_code);
2190 // no si_addr
2191 }
2192
2193 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2194 UseSharedSpaces) {
2195 FileMapInfo* mapinfo = FileMapInfo::current_info();
2196 if (mapinfo->is_in_shared_space(si->si_addr)) {
2197 st->print("\n\nError accessing class data sharing archive." \
2198 " Mapped file inaccessible during execution, " \
2199 " possible disk/network problem.");
2200 }
2201 }
2202 st->cr();
2203 }
2204
2205
2206 static void print_signal_handler(outputStream* st, int sig,
2207 char* buf, size_t buflen);
2208
2209 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2210 st->print_cr("Signal Handlers:");
2211 print_signal_handler(st, SIGSEGV, buf, buflen);
2212 print_signal_handler(st, SIGBUS , buf, buflen);
2213 print_signal_handler(st, SIGFPE , buf, buflen);
2214 print_signal_handler(st, SIGPIPE, buf, buflen);
2215 print_signal_handler(st, SIGXFSZ, buf, buflen);
2216 print_signal_handler(st, SIGILL , buf, buflen);
2217 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2218 print_signal_handler(st, SR_signum, buf, buflen);
2219 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2220 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2221 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2222 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2223 }
2224
2225 static char saved_jvm_path[MAXPATHLEN] = {0};
2226
2227 // Find the full path to the current module, libjvm.so or libjvm_g.so
2228 void os::jvm_path(char *buf, jint buflen) {
2229 // Error checking.
2230 if (buflen < MAXPATHLEN) {
2231 assert(false, "must use a large-enough buffer");
2232 buf[0] = '\0';
2233 return;
2234 }
2235 // Lazy resolve the path to current module.
2236 if (saved_jvm_path[0] != 0) {
2237 strcpy(buf, saved_jvm_path);
2238 return;
2239 }
2240
2241 char dli_fname[MAXPATHLEN];
2242 bool ret = dll_address_to_library_name(
2243 CAST_FROM_FN_PTR(address, os::jvm_path),
2244 dli_fname, sizeof(dli_fname), NULL);
2245 assert(ret != 0, "cannot locate libjvm");
2246 char *rp = realpath(dli_fname, buf);
2247 if (rp == NULL)
2248 return;
2249
2250 if (Arguments::created_by_gamma_launcher()) {
2251 // Support for the gamma launcher. Typical value for buf is
2252 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2253 // the right place in the string, then assume we are installed in a JDK and
2254 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2255 // up the path so it looks like libjvm.so is installed there (append a
2256 // fake suffix hotspot/libjvm.so).
2257 const char *p = buf + strlen(buf) - 1;
2258 for (int count = 0; p > buf && count < 5; ++count) {
2259 for (--p; p > buf && *p != '/'; --p)
2260 /* empty */ ;
2261 }
2262
2263 if (strncmp(p, "/jre/lib/", 9) != 0) {
2264 // Look for JAVA_HOME in the environment.
2265 char* java_home_var = ::getenv("JAVA_HOME");
2266 if (java_home_var != NULL && java_home_var[0] != 0) {
2267 char* jrelib_p;
2268 int len;
2269
2270 // Check the current module name "libjvm.so" or "libjvm_g.so".
2271 p = strrchr(buf, '/');
2272 assert(strstr(p, "/libjvm") == p, "invalid library name");
2273 p = strstr(p, "_g") ? "_g" : "";
2274
2275 rp = realpath(java_home_var, buf);
2276 if (rp == NULL)
2277 return;
2278
2279 // determine if this is a legacy image or modules image
2280 // modules image doesn't have "jre" subdirectory
2281 len = strlen(buf);
2282 jrelib_p = buf + len;
2283 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2284 if (0 != access(buf, F_OK)) {
2285 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2286 }
2287
2288 if (0 == access(buf, F_OK)) {
2289 // Use current module name "libjvm[_g].so" instead of
2290 // "libjvm"debug_only("_g")".so" since for fastdebug version
2291 // we should have "libjvm.so" but debug_only("_g") adds "_g"!
2292 len = strlen(buf);
2293 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p);
2294 } else {
2295 // Go back to path of .so
2296 rp = realpath(dli_fname, buf);
2297 if (rp == NULL)
2298 return;
2299 }
2300 }
2301 }
2302 }
2303
2304 strcpy(saved_jvm_path, buf);
2305 }
2306
2307 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2308 // no prefix required, not even "_"
2309 }
2310
2311 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2312 // no suffix required
2313 }
2314
2315 ////////////////////////////////////////////////////////////////////////////////
2316 // sun.misc.Signal support
2317
2318 static volatile jint sigint_count = 0;
2319
2320 static void
2321 UserHandler(int sig, void *siginfo, void *context) {
2322 // 4511530 - sem_post is serialized and handled by the manager thread. When
2323 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2324 // don't want to flood the manager thread with sem_post requests.
2325 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2326 return;
2327
2328 // Ctrl-C is pressed during error reporting, likely because the error
2329 // handler fails to abort. Let VM die immediately.
2330 if (sig == SIGINT && is_error_reported()) {
2331 os::die();
2332 }
2333
2334 os::signal_notify(sig);
2335 }
2336
2337 void* os::user_handler() {
2338 return CAST_FROM_FN_PTR(void*, UserHandler);
2339 }
2340
2341 extern "C" {
2342 typedef void (*sa_handler_t)(int);
2343 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2344 }
2345
2346 void* os::signal(int signal_number, void* handler) {
2347 struct sigaction sigAct, oldSigAct;
2348
2349 sigfillset(&(sigAct.sa_mask));
2350 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2351 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2352
2353 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2354 // -1 means registration failed
2355 return (void *)-1;
2356 }
2357
2358 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2359 }
2360
2361 void os::signal_raise(int signal_number) {
2362 ::raise(signal_number);
2363 }
2364
2365 /*
2366 * The following code is moved from os.cpp for making this
2367 * code platform specific, which it is by its very nature.
2368 */
2369
2370 // Will be modified when max signal is changed to be dynamic
2371 int os::sigexitnum_pd() {
2372 return NSIG;
2373 }
2374
2375 // a counter for each possible signal value
2376 static volatile jint pending_signals[NSIG+1] = { 0 };
2377
2378 // Linux(POSIX) specific hand shaking semaphore.
2379 static sem_t sig_sem;
2380
2381 void os::signal_init_pd() {
2382 // Initialize signal structures
2383 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2384
2385 // Initialize signal semaphore
2386 ::sem_init(&sig_sem, 0, 0);
2387 }
2388
2389 void os::signal_notify(int sig) {
2390 Atomic::inc(&pending_signals[sig]);
2391 ::sem_post(&sig_sem);
2392 }
2393
2394 static int check_pending_signals(bool wait) {
2395 Atomic::store(0, &sigint_count);
2396 for (;;) {
2397 for (int i = 0; i < NSIG + 1; i++) {
2398 jint n = pending_signals[i];
2399 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2400 return i;
2401 }
2402 }
2403 if (!wait) {
2404 return -1;
2405 }
2406 JavaThread *thread = JavaThread::current();
2407 ThreadBlockInVM tbivm(thread);
2408
2409 bool threadIsSuspended;
2410 do {
2411 thread->set_suspend_equivalent();
2412 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2413 ::sem_wait(&sig_sem);
2414
2415 // were we externally suspended while we were waiting?
2416 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2417 if (threadIsSuspended) {
2418 //
2419 // The semaphore has been incremented, but while we were waiting
2420 // another thread suspended us. We don't want to continue running
2421 // while suspended because that would surprise the thread that
2422 // suspended us.
2423 //
2424 ::sem_post(&sig_sem);
2425
2426 thread->java_suspend_self();
2427 }
2428 } while (threadIsSuspended);
2429 }
2430 }
2431
2432 int os::signal_lookup() {
2433 return check_pending_signals(false);
2434 }
2435
2436 int os::signal_wait() {
2437 return check_pending_signals(true);
2438 }
2439
2440 ////////////////////////////////////////////////////////////////////////////////
2441 // Virtual Memory
2442
2443 int os::vm_page_size() {
2444 // Seems redundant as all get out
2445 assert(os::Linux::page_size() != -1, "must call os::init");
2446 return os::Linux::page_size();
2447 }
2448
2449 // Solaris allocates memory by pages.
2450 int os::vm_allocation_granularity() {
2451 assert(os::Linux::page_size() != -1, "must call os::init");
2452 return os::Linux::page_size();
2453 }
2454
2455 // Rationale behind this function:
2456 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2457 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2458 // samples for JITted code. Here we create private executable mapping over the code cache
2459 // and then we can use standard (well, almost, as mapping can change) way to provide
2460 // info for the reporting script by storing timestamp and location of symbol
2461 void linux_wrap_code(char* base, size_t size) {
2462 static volatile jint cnt = 0;
2463
2464 if (!UseOprofile) {
2465 return;
2466 }
2467
2468 char buf[PATH_MAX+1];
2469 int num = Atomic::add(1, &cnt);
2470
2471 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2472 os::get_temp_directory(), os::current_process_id(), num);
2473 unlink(buf);
2474
2475 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2476
2477 if (fd != -1) {
2478 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2479 if (rv != (off_t)-1) {
2480 if (::write(fd, "", 1) == 1) {
2481 mmap(base, size,
2482 PROT_READ|PROT_WRITE|PROT_EXEC,
2483 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2484 }
2485 }
2486 ::close(fd);
2487 unlink(buf);
2488 }
2489 }
2490
2491 // NOTE: Linux kernel does not really reserve the pages for us.
2492 // All it does is to check if there are enough free pages
2493 // left at the time of mmap(). This could be a potential
2494 // problem.
2495 bool os::commit_memory(char* addr, size_t size, bool exec) {
2496 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2497 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2498 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2499 if (res != (uintptr_t) MAP_FAILED) {
2500 if (UseNUMAInterleaving) {
2501 numa_make_global(addr, size);
2502 }
2503 return true;
2504 }
2505 return false;
2506 }
2507
2508 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2509 #ifndef MAP_HUGETLB
2510 #define MAP_HUGETLB 0x40000
2511 #endif
2512
2513 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2514 #ifndef MADV_HUGEPAGE
2515 #define MADV_HUGEPAGE 14
2516 #endif
2517
2518 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
2519 bool exec) {
2520 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2521 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2522 uintptr_t res =
2523 (uintptr_t) ::mmap(addr, size, prot,
2524 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB,
2525 -1, 0);
2526 if (res != (uintptr_t) MAP_FAILED) {
2527 if (UseNUMAInterleaving) {
2528 numa_make_global(addr, size);
2529 }
2530 return true;
2531 }
2532 // Fall through and try to use small pages
2533 }
2534
2535 if (commit_memory(addr, size, exec)) {
2536 realign_memory(addr, size, alignment_hint);
2537 return true;
2538 }
2539 return false;
2540 }
2541
2542 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2543 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2544 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2545 // be supported or the memory may already be backed by huge pages.
2546 ::madvise(addr, bytes, MADV_HUGEPAGE);
2547 }
2548 }
2549
2550 void os::free_memory(char *addr, size_t bytes) {
2551 commit_memory(addr, bytes, false);
2552 }
2553
2554 void os::numa_make_global(char *addr, size_t bytes) {
2555 Linux::numa_interleave_memory(addr, bytes);
2556 }
2557
2558 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2559 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2560 }
2561
2562 bool os::numa_topology_changed() { return false; }
2563
2564 size_t os::numa_get_groups_num() {
2565 int max_node = Linux::numa_max_node();
2566 return max_node > 0 ? max_node + 1 : 1;
2567 }
2568
2569 int os::numa_get_group_id() {
2570 int cpu_id = Linux::sched_getcpu();
2571 if (cpu_id != -1) {
2572 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2573 if (lgrp_id != -1) {
2574 return lgrp_id;
2575 }
2576 }
2577 return 0;
2578 }
2579
2580 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2581 for (size_t i = 0; i < size; i++) {
2582 ids[i] = i;
2583 }
2584 return size;
2585 }
2586
2587 bool os::get_page_info(char *start, page_info* info) {
2588 return false;
2589 }
2590
2591 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2592 return end;
2593 }
2594
2595
2596 int os::Linux::sched_getcpu_syscall(void) {
2597 unsigned int cpu;
2598 int retval = -1;
2599
2600 #if defined(IA32)
2601 # ifndef SYS_getcpu
2602 # define SYS_getcpu 318
2603 # endif
2604 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2605 #elif defined(AMD64)
2606 // Unfortunately we have to bring all these macros here from vsyscall.h
2607 // to be able to compile on old linuxes.
2608 # define __NR_vgetcpu 2
2609 # define VSYSCALL_START (-10UL << 20)
2610 # define VSYSCALL_SIZE 1024
2611 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2612 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2613 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2614 retval = vgetcpu(&cpu, NULL, NULL);
2615 #endif
2616
2617 return (retval == -1) ? retval : cpu;
2618 }
2619
2620 // Something to do with the numa-aware allocator needs these symbols
2621 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2622 extern "C" JNIEXPORT void numa_error(char *where) { }
2623 extern "C" JNIEXPORT int fork1() { return fork(); }
2624
2625
2626 // If we are running with libnuma version > 2, then we should
2627 // be trying to use symbols with versions 1.1
2628 // If we are running with earlier version, which did not have symbol versions,
2629 // we should use the base version.
2630 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2631 void *f = dlvsym(handle, name, "libnuma_1.1");
2632 if (f == NULL) {
2633 f = dlsym(handle, name);
2634 }
2635 return f;
2636 }
2637
2638 bool os::Linux::libnuma_init() {
2639 // sched_getcpu() should be in libc.
2640 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2641 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2642
2643 // If it's not, try a direct syscall.
2644 if (sched_getcpu() == -1)
2645 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2646
2647 if (sched_getcpu() != -1) { // Does it work?
2648 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2649 if (handle != NULL) {
2650 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2651 libnuma_dlsym(handle, "numa_node_to_cpus")));
2652 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2653 libnuma_dlsym(handle, "numa_max_node")));
2654 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2655 libnuma_dlsym(handle, "numa_available")));
2656 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2657 libnuma_dlsym(handle, "numa_tonode_memory")));
2658 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2659 libnuma_dlsym(handle, "numa_interleave_memory")));
2660
2661
2662 if (numa_available() != -1) {
2663 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2664 // Create a cpu -> node mapping
2665 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true);
2666 rebuild_cpu_to_node_map();
2667 return true;
2668 }
2669 }
2670 }
2671 return false;
2672 }
2673
2674 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2675 // The table is later used in get_node_by_cpu().
2676 void os::Linux::rebuild_cpu_to_node_map() {
2677 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2678 // in libnuma (possible values are starting from 16,
2679 // and continuing up with every other power of 2, but less
2680 // than the maximum number of CPUs supported by kernel), and
2681 // is a subject to change (in libnuma version 2 the requirements
2682 // are more reasonable) we'll just hardcode the number they use
2683 // in the library.
2684 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2685
2686 size_t cpu_num = os::active_processor_count();
2687 size_t cpu_map_size = NCPUS / BitsPerCLong;
2688 size_t cpu_map_valid_size =
2689 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2690
2691 cpu_to_node()->clear();
2692 cpu_to_node()->at_grow(cpu_num - 1);
2693 size_t node_num = numa_get_groups_num();
2694
2695 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size);
2696 for (size_t i = 0; i < node_num; i++) {
2697 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2698 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2699 if (cpu_map[j] != 0) {
2700 for (size_t k = 0; k < BitsPerCLong; k++) {
2701 if (cpu_map[j] & (1UL << k)) {
2702 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2703 }
2704 }
2705 }
2706 }
2707 }
2708 }
2709 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2710 }
2711
2712 int os::Linux::get_node_by_cpu(int cpu_id) {
2713 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2714 return cpu_to_node()->at(cpu_id);
2715 }
2716 return -1;
2717 }
2718
2719 GrowableArray<int>* os::Linux::_cpu_to_node;
2720 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2721 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2722 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2723 os::Linux::numa_available_func_t os::Linux::_numa_available;
2724 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2725 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2726 unsigned long* os::Linux::_numa_all_nodes;
2727
2728 bool os::uncommit_memory(char* addr, size_t size) {
2729 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2730 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2731 return res != (uintptr_t) MAP_FAILED;
2732 }
2733
2734 // Linux uses a growable mapping for the stack, and if the mapping for
2735 // the stack guard pages is not removed when we detach a thread the
2736 // stack cannot grow beyond the pages where the stack guard was
2737 // mapped. If at some point later in the process the stack expands to
2738 // that point, the Linux kernel cannot expand the stack any further
2739 // because the guard pages are in the way, and a segfault occurs.
2740 //
2741 // However, it's essential not to split the stack region by unmapping
2742 // a region (leaving a hole) that's already part of the stack mapping,
2743 // so if the stack mapping has already grown beyond the guard pages at
2744 // the time we create them, we have to truncate the stack mapping.
2745 // So, we need to know the extent of the stack mapping when
2746 // create_stack_guard_pages() is called.
2747
2748 // Find the bounds of the stack mapping. Return true for success.
2749 //
2750 // We only need this for stacks that are growable: at the time of
2751 // writing thread stacks don't use growable mappings (i.e. those
2752 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2753 // only applies to the main thread.
2754
2755 static
2756 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) {
2757
2758 char buf[128];
2759 int fd, sz;
2760
2761 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) {
2762 return false;
2763 }
2764
2765 const char kw[] = "[stack]";
2766 const int kwlen = sizeof(kw)-1;
2767
2768 // Address part of /proc/self/maps couldn't be more than 128 bytes
2769 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) {
2770 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) {
2771 // Extract addresses
2772 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
2773 uintptr_t sp = (uintptr_t) __builtin_frame_address(0);
2774 if (sp >= *bottom && sp <= *top) {
2775 ::close(fd);
2776 return true;
2777 }
2778 }
2779 }
2780 }
2781
2782 ::close(fd);
2783 return false;
2784 }
2785
2786
2787 // If the (growable) stack mapping already extends beyond the point
2788 // where we're going to put our guard pages, truncate the mapping at
2789 // that point by munmap()ping it. This ensures that when we later
2790 // munmap() the guard pages we don't leave a hole in the stack
2791 // mapping. This only affects the main/initial thread, but guard
2792 // against future OS changes
2793 bool os::create_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 if (stack_extent < (uintptr_t)addr)
2800 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent);
2801 }
2802
2803 return os::commit_memory(addr, size);
2804 }
2805
2806 // If this is a growable mapping, remove the guard pages entirely by
2807 // munmap()ping them. If not, just call uncommit_memory(). This only
2808 // affects the main/initial thread, but guard against future OS changes
2809 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2810 uintptr_t stack_extent, stack_base;
2811 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2812 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2813 assert(os::Linux::is_initial_thread(),
2814 "growable stack in non-initial thread");
2815
2816 return ::munmap(addr, size) == 0;
2817 }
2818
2819 return os::uncommit_memory(addr, size);
2820 }
2821
2822 static address _highest_vm_reserved_address = NULL;
2823
2824 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2825 // at 'requested_addr'. If there are existing memory mappings at the same
2826 // location, however, they will be overwritten. If 'fixed' is false,
2827 // 'requested_addr' is only treated as a hint, the return value may or
2828 // may not start from the requested address. Unlike Linux mmap(), this
2829 // function returns NULL to indicate failure.
2830 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2831 char * addr;
2832 int flags;
2833
2834 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2835 if (fixed) {
2836 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
2837 flags |= MAP_FIXED;
2838 }
2839
2840 // Map uncommitted pages PROT_READ and PROT_WRITE, change access
2841 // to PROT_EXEC if executable when we commit the page.
2842 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE,
2843 flags, -1, 0);
2844
2845 if (addr != MAP_FAILED) {
2846 // anon_mmap() should only get called during VM initialization,
2847 // don't need lock (actually we can skip locking even it can be called
2848 // from multiple threads, because _highest_vm_reserved_address is just a
2849 // hint about the upper limit of non-stack memory regions.)
2850 if ((address)addr + bytes > _highest_vm_reserved_address) {
2851 _highest_vm_reserved_address = (address)addr + bytes;
2852 }
2853 }
2854
2855 return addr == MAP_FAILED ? NULL : addr;
2856 }
2857
2858 // Don't update _highest_vm_reserved_address, because there might be memory
2859 // regions above addr + size. If so, releasing a memory region only creates
2860 // a hole in the address space, it doesn't help prevent heap-stack collision.
2861 //
2862 static int anon_munmap(char * addr, size_t size) {
2863 return ::munmap(addr, size) == 0;
2864 }
2865
2866 char* os::reserve_memory(size_t bytes, char* requested_addr,
2867 size_t alignment_hint) {
2868 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2869 }
2870
2871 bool os::release_memory(char* addr, size_t size) {
2872 return anon_munmap(addr, size);
2873 }
2874
2875 static address highest_vm_reserved_address() {
2876 return _highest_vm_reserved_address;
2877 }
2878
2879 static bool linux_mprotect(char* addr, size_t size, int prot) {
2880 // Linux wants the mprotect address argument to be page aligned.
2881 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
2882
2883 // According to SUSv3, mprotect() should only be used with mappings
2884 // established by mmap(), and mmap() always maps whole pages. Unaligned
2885 // 'addr' likely indicates problem in the VM (e.g. trying to change
2886 // protection of malloc'ed or statically allocated memory). Check the
2887 // caller if you hit this assert.
2888 assert(addr == bottom, "sanity check");
2889
2890 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
2891 return ::mprotect(bottom, size, prot) == 0;
2892 }
2893
2894 // Set protections specified
2895 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2896 bool is_committed) {
2897 unsigned int p = 0;
2898 switch (prot) {
2899 case MEM_PROT_NONE: p = PROT_NONE; break;
2900 case MEM_PROT_READ: p = PROT_READ; break;
2901 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
2902 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2903 default:
2904 ShouldNotReachHere();
2905 }
2906 // is_committed is unused.
2907 return linux_mprotect(addr, bytes, p);
2908 }
2909
2910 bool os::guard_memory(char* addr, size_t size) {
2911 return linux_mprotect(addr, size, PROT_NONE);
2912 }
2913
2914 bool os::unguard_memory(char* addr, size_t size) {
2915 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2916 }
2917
2918 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2919 bool result = false;
2920 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE,
2921 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
2922 -1, 0);
2923
2924 if (p != (void *) -1) {
2925 // We don't know if this really is a huge page or not.
2926 FILE *fp = fopen("/proc/self/maps", "r");
2927 if (fp) {
2928 while (!feof(fp)) {
2929 char chars[257];
2930 long x = 0;
2931 if (fgets(chars, sizeof(chars), fp)) {
2932 if (sscanf(chars, "%lx-%*x", &x) == 1
2933 && x == (long)p) {
2934 if (strstr (chars, "hugepage")) {
2935 result = true;
2936 break;
2937 }
2938 }
2939 }
2940 }
2941 fclose(fp);
2942 }
2943 munmap (p, page_size);
2944 if (result)
2945 return true;
2946 }
2947
2948 if (warn) {
2949 warning("HugeTLBFS is not supported by the operating system.");
2950 }
2951
2952 return result;
2953 }
2954
2955 /*
2956 * Set the coredump_filter bits to include largepages in core dump (bit 6)
2957 *
2958 * From the coredump_filter documentation:
2959 *
2960 * - (bit 0) anonymous private memory
2961 * - (bit 1) anonymous shared memory
2962 * - (bit 2) file-backed private memory
2963 * - (bit 3) file-backed shared memory
2964 * - (bit 4) ELF header pages in file-backed private memory areas (it is
2965 * effective only if the bit 2 is cleared)
2966 * - (bit 5) hugetlb private memory
2967 * - (bit 6) hugetlb shared memory
2968 */
2969 static void set_coredump_filter(void) {
2970 FILE *f;
2971 long cdm;
2972
2973 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
2974 return;
2975 }
2976
2977 if (fscanf(f, "%lx", &cdm) != 1) {
2978 fclose(f);
2979 return;
2980 }
2981
2982 rewind(f);
2983
2984 if ((cdm & LARGEPAGES_BIT) == 0) {
2985 cdm |= LARGEPAGES_BIT;
2986 fprintf(f, "%#lx", cdm);
2987 }
2988
2989 fclose(f);
2990 }
2991
2992 // Large page support
2993
2994 static size_t _large_page_size = 0;
2995
2996 void os::large_page_init() {
2997 if (!UseLargePages) {
2998 UseHugeTLBFS = false;
2999 UseSHM = false;
3000 return;
3001 }
3002
3003 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) {
3004 // If UseLargePages is specified on the command line try both methods,
3005 // if it's default, then try only HugeTLBFS.
3006 if (FLAG_IS_DEFAULT(UseLargePages)) {
3007 UseHugeTLBFS = true;
3008 } else {
3009 UseHugeTLBFS = UseSHM = true;
3010 }
3011 }
3012
3013 if (LargePageSizeInBytes) {
3014 _large_page_size = LargePageSizeInBytes;
3015 } else {
3016 // large_page_size on Linux is used to round up heap size. x86 uses either
3017 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3018 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3019 // page as large as 256M.
3020 //
3021 // Here we try to figure out page size by parsing /proc/meminfo and looking
3022 // for a line with the following format:
3023 // Hugepagesize: 2048 kB
3024 //
3025 // If we can't determine the value (e.g. /proc is not mounted, or the text
3026 // format has been changed), we'll use the largest page size supported by
3027 // the processor.
3028
3029 #ifndef ZERO
3030 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3031 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
3032 #endif // ZERO
3033
3034 FILE *fp = fopen("/proc/meminfo", "r");
3035 if (fp) {
3036 while (!feof(fp)) {
3037 int x = 0;
3038 char buf[16];
3039 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3040 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3041 _large_page_size = x * K;
3042 break;
3043 }
3044 } else {
3045 // skip to next line
3046 for (;;) {
3047 int ch = fgetc(fp);
3048 if (ch == EOF || ch == (int)'\n') break;
3049 }
3050 }
3051 }
3052 fclose(fp);
3053 }
3054 }
3055
3056 // print a warning if any large page related flag is specified on command line
3057 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3058
3059 const size_t default_page_size = (size_t)Linux::page_size();
3060 if (_large_page_size > default_page_size) {
3061 _page_sizes[0] = _large_page_size;
3062 _page_sizes[1] = default_page_size;
3063 _page_sizes[2] = 0;
3064 }
3065 UseHugeTLBFS = UseHugeTLBFS &&
3066 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size);
3067
3068 if (UseHugeTLBFS)
3069 UseSHM = false;
3070
3071 UseLargePages = UseHugeTLBFS || UseSHM;
3072
3073 set_coredump_filter();
3074 }
3075
3076 #ifndef SHM_HUGETLB
3077 #define SHM_HUGETLB 04000
3078 #endif
3079
3080 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
3081 // "exec" is passed in but not used. Creating the shared image for
3082 // the code cache doesn't have an SHM_X executable permission to check.
3083 assert(UseLargePages && UseSHM, "only for SHM large pages");
3084
3085 key_t key = IPC_PRIVATE;
3086 char *addr;
3087
3088 bool warn_on_failure = UseLargePages &&
3089 (!FLAG_IS_DEFAULT(UseLargePages) ||
3090 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3091 );
3092 char msg[128];
3093
3094 // Create a large shared memory region to attach to based on size.
3095 // Currently, size is the total size of the heap
3096 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3097 if (shmid == -1) {
3098 // Possible reasons for shmget failure:
3099 // 1. shmmax is too small for Java heap.
3100 // > check shmmax value: cat /proc/sys/kernel/shmmax
3101 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3102 // 2. not enough large page memory.
3103 // > check available large pages: cat /proc/meminfo
3104 // > increase amount of large pages:
3105 // echo new_value > /proc/sys/vm/nr_hugepages
3106 // Note 1: different Linux may use different name for this property,
3107 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3108 // Note 2: it's possible there's enough physical memory available but
3109 // they are so fragmented after a long run that they can't
3110 // coalesce into large pages. Try to reserve large pages when
3111 // the system is still "fresh".
3112 if (warn_on_failure) {
3113 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3114 warning(msg);
3115 }
3116 return NULL;
3117 }
3118
3119 // attach to the region
3120 addr = (char*)shmat(shmid, req_addr, 0);
3121 int err = errno;
3122
3123 // Remove shmid. If shmat() is successful, the actual shared memory segment
3124 // will be deleted when it's detached by shmdt() or when the process
3125 // terminates. If shmat() is not successful this will remove the shared
3126 // segment immediately.
3127 shmctl(shmid, IPC_RMID, NULL);
3128
3129 if ((intptr_t)addr == -1) {
3130 if (warn_on_failure) {
3131 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3132 warning(msg);
3133 }
3134 return NULL;
3135 }
3136
3137 if ((addr != NULL) && UseNUMAInterleaving) {
3138 numa_make_global(addr, bytes);
3139 }
3140
3141 return addr;
3142 }
3143
3144 bool os::release_memory_special(char* base, size_t bytes) {
3145 // detaching the SHM segment will also delete it, see reserve_memory_special()
3146 int rslt = shmdt(base);
3147 return rslt == 0;
3148 }
3149
3150 size_t os::large_page_size() {
3151 return _large_page_size;
3152 }
3153
3154 // HugeTLBFS allows application to commit large page memory on demand;
3155 // with SysV SHM the entire memory region must be allocated as shared
3156 // memory.
3157 bool os::can_commit_large_page_memory() {
3158 return UseHugeTLBFS;
3159 }
3160
3161 bool os::can_execute_large_page_memory() {
3162 return UseHugeTLBFS;
3163 }
3164
3165 // Reserve memory at an arbitrary address, only if that area is
3166 // available (and not reserved for something else).
3167
3168 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3169 const int max_tries = 10;
3170 char* base[max_tries];
3171 size_t size[max_tries];
3172 const size_t gap = 0x000000;
3173
3174 // Assert only that the size is a multiple of the page size, since
3175 // that's all that mmap requires, and since that's all we really know
3176 // about at this low abstraction level. If we need higher alignment,
3177 // we can either pass an alignment to this method or verify alignment
3178 // in one of the methods further up the call chain. See bug 5044738.
3179 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3180
3181 // Repeatedly allocate blocks until the block is allocated at the
3182 // right spot. Give up after max_tries. Note that reserve_memory() will
3183 // automatically update _highest_vm_reserved_address if the call is
3184 // successful. The variable tracks the highest memory address every reserved
3185 // by JVM. It is used to detect heap-stack collision if running with
3186 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3187 // space than needed, it could confuse the collision detecting code. To
3188 // solve the problem, save current _highest_vm_reserved_address and
3189 // calculate the correct value before return.
3190 address old_highest = _highest_vm_reserved_address;
3191
3192 // Linux mmap allows caller to pass an address as hint; give it a try first,
3193 // if kernel honors the hint then we can return immediately.
3194 char * addr = anon_mmap(requested_addr, bytes, false);
3195 if (addr == requested_addr) {
3196 return requested_addr;
3197 }
3198
3199 if (addr != NULL) {
3200 // mmap() is successful but it fails to reserve at the requested address
3201 anon_munmap(addr, bytes);
3202 }
3203
3204 int i;
3205 for (i = 0; i < max_tries; ++i) {
3206 base[i] = reserve_memory(bytes);
3207
3208 if (base[i] != NULL) {
3209 // Is this the block we wanted?
3210 if (base[i] == requested_addr) {
3211 size[i] = bytes;
3212 break;
3213 }
3214
3215 // Does this overlap the block we wanted? Give back the overlapped
3216 // parts and try again.
3217
3218 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3219 if (top_overlap >= 0 && top_overlap < bytes) {
3220 unmap_memory(base[i], top_overlap);
3221 base[i] += top_overlap;
3222 size[i] = bytes - top_overlap;
3223 } else {
3224 size_t bottom_overlap = base[i] + bytes - requested_addr;
3225 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3226 unmap_memory(requested_addr, bottom_overlap);
3227 size[i] = bytes - bottom_overlap;
3228 } else {
3229 size[i] = bytes;
3230 }
3231 }
3232 }
3233 }
3234
3235 // Give back the unused reserved pieces.
3236
3237 for (int j = 0; j < i; ++j) {
3238 if (base[j] != NULL) {
3239 unmap_memory(base[j], size[j]);
3240 }
3241 }
3242
3243 if (i < max_tries) {
3244 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3245 return requested_addr;
3246 } else {
3247 _highest_vm_reserved_address = old_highest;
3248 return NULL;
3249 }
3250 }
3251
3252 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3253 return ::read(fd, buf, nBytes);
3254 }
3255
3256 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
3257 // Solaris uses poll(), linux uses park().
3258 // Poll() is likely a better choice, assuming that Thread.interrupt()
3259 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
3260 // SIGSEGV, see 4355769.
3261
3262 const int NANOSECS_PER_MILLISECS = 1000000;
3263
3264 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
3265 assert(thread == Thread::current(), "thread consistency check");
3266
3267 ParkEvent * const slp = thread->_SleepEvent ;
3268 slp->reset() ;
3269 OrderAccess::fence() ;
3270
3271 if (interruptible) {
3272 jlong prevtime = javaTimeNanos();
3273
3274 for (;;) {
3275 if (os::is_interrupted(thread, true)) {
3276 return OS_INTRPT;
3277 }
3278
3279 jlong newtime = javaTimeNanos();
3280
3281 if (newtime - prevtime < 0) {
3282 // time moving backwards, should only happen if no monotonic clock
3283 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3284 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3285 } else {
3286 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
3287 }
3288
3289 if(millis <= 0) {
3290 return OS_OK;
3291 }
3292
3293 prevtime = newtime;
3294
3295 {
3296 assert(thread->is_Java_thread(), "sanity check");
3297 JavaThread *jt = (JavaThread *) thread;
3298 ThreadBlockInVM tbivm(jt);
3299 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
3300
3301 jt->set_suspend_equivalent();
3302 // cleared by handle_special_suspend_equivalent_condition() or
3303 // java_suspend_self() via check_and_wait_while_suspended()
3304
3305 slp->park(millis);
3306
3307 // were we externally suspended while we were waiting?
3308 jt->check_and_wait_while_suspended();
3309 }
3310 }
3311 } else {
3312 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
3313 jlong prevtime = javaTimeNanos();
3314
3315 for (;;) {
3316 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
3317 // the 1st iteration ...
3318 jlong newtime = javaTimeNanos();
3319
3320 if (newtime - prevtime < 0) {
3321 // time moving backwards, should only happen if no monotonic clock
3322 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3323 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3324 } else {
3325 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
3326 }
3327
3328 if(millis <= 0) break ;
3329
3330 prevtime = newtime;
3331 slp->park(millis);
3332 }
3333 return OS_OK ;
3334 }
3335 }
3336
3337 int os::naked_sleep() {
3338 // %% make the sleep time an integer flag. for now use 1 millisec.
3339 return os::sleep(Thread::current(), 1, false);
3340 }
3341
3342 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3343 void os::infinite_sleep() {
3344 while (true) { // sleep forever ...
3345 ::sleep(100); // ... 100 seconds at a time
3346 }
3347 }
3348
3349 // Used to convert frequent JVM_Yield() to nops
3350 bool os::dont_yield() {
3351 return DontYieldALot;
3352 }
3353
3354 void os::yield() {
3355 sched_yield();
3356 }
3357
3358 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3359
3360 void os::yield_all(int attempts) {
3361 // Yields to all threads, including threads with lower priorities
3362 // Threads on Linux are all with same priority. The Solaris style
3363 // os::yield_all() with nanosleep(1ms) is not necessary.
3364 sched_yield();
3365 }
3366
3367 // Called from the tight loops to possibly influence time-sharing heuristics
3368 void os::loop_breaker(int attempts) {
3369 os::yield_all(attempts);
3370 }
3371
3372 ////////////////////////////////////////////////////////////////////////////////
3373 // thread priority support
3374
3375 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3376 // only supports dynamic priority, static priority must be zero. For real-time
3377 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3378 // However, for large multi-threaded applications, SCHED_RR is not only slower
3379 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3380 // of 5 runs - Sep 2005).
3381 //
3382 // The following code actually changes the niceness of kernel-thread/LWP. It
3383 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3384 // not the entire user process, and user level threads are 1:1 mapped to kernel
3385 // threads. It has always been the case, but could change in the future. For
3386 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3387 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3388
3389 int os::java_to_os_priority[MaxPriority + 1] = {
3390 19, // 0 Entry should never be used
3391
3392 4, // 1 MinPriority
3393 3, // 2
3394 2, // 3
3395
3396 1, // 4
3397 0, // 5 NormPriority
3398 -1, // 6
3399
3400 -2, // 7
3401 -3, // 8
3402 -4, // 9 NearMaxPriority
3403
3404 -5 // 10 MaxPriority
3405 };
3406
3407 static int prio_init() {
3408 if (ThreadPriorityPolicy == 1) {
3409 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3410 // if effective uid is not root. Perhaps, a more elegant way of doing
3411 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3412 if (geteuid() != 0) {
3413 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3414 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3415 }
3416 ThreadPriorityPolicy = 0;
3417 }
3418 }
3419 return 0;
3420 }
3421
3422 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3423 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3424
3425 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3426 return (ret == 0) ? OS_OK : OS_ERR;
3427 }
3428
3429 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3430 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3431 *priority_ptr = java_to_os_priority[NormPriority];
3432 return OS_OK;
3433 }
3434
3435 errno = 0;
3436 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3437 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3438 }
3439
3440 // Hint to the underlying OS that a task switch would not be good.
3441 // Void return because it's a hint and can fail.
3442 void os::hint_no_preempt() {}
3443
3444 ////////////////////////////////////////////////////////////////////////////////
3445 // suspend/resume support
3446
3447 // the low-level signal-based suspend/resume support is a remnant from the
3448 // old VM-suspension that used to be for java-suspension, safepoints etc,
3449 // within hotspot. Now there is a single use-case for this:
3450 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3451 // that runs in the watcher thread.
3452 // The remaining code is greatly simplified from the more general suspension
3453 // code that used to be used.
3454 //
3455 // The protocol is quite simple:
3456 // - suspend:
3457 // - sends a signal to the target thread
3458 // - polls the suspend state of the osthread using a yield loop
3459 // - target thread signal handler (SR_handler) sets suspend state
3460 // and blocks in sigsuspend until continued
3461 // - resume:
3462 // - sets target osthread state to continue
3463 // - sends signal to end the sigsuspend loop in the SR_handler
3464 //
3465 // Note that the SR_lock plays no role in this suspend/resume protocol.
3466 //
3467
3468 static void resume_clear_context(OSThread *osthread) {
3469 osthread->set_ucontext(NULL);
3470 osthread->set_siginfo(NULL);
3471
3472 // notify the suspend action is completed, we have now resumed
3473 osthread->sr.clear_suspended();
3474 }
3475
3476 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3477 osthread->set_ucontext(context);
3478 osthread->set_siginfo(siginfo);
3479 }
3480
3481 //
3482 // Handler function invoked when a thread's execution is suspended or
3483 // resumed. We have to be careful that only async-safe functions are
3484 // called here (Note: most pthread functions are not async safe and
3485 // should be avoided.)
3486 //
3487 // Note: sigwait() is a more natural fit than sigsuspend() from an
3488 // interface point of view, but sigwait() prevents the signal hander
3489 // from being run. libpthread would get very confused by not having
3490 // its signal handlers run and prevents sigwait()'s use with the
3491 // mutex granting granting signal.
3492 //
3493 // Currently only ever called on the VMThread
3494 //
3495 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3496 // Save and restore errno to avoid confusing native code with EINTR
3497 // after sigsuspend.
3498 int old_errno = errno;
3499
3500 Thread* thread = Thread::current();
3501 OSThread* osthread = thread->osthread();
3502 assert(thread->is_VM_thread(), "Must be VMThread");
3503 // read current suspend action
3504 int action = osthread->sr.suspend_action();
3505 if (action == SR_SUSPEND) {
3506 suspend_save_context(osthread, siginfo, context);
3507
3508 // Notify the suspend action is about to be completed. do_suspend()
3509 // waits until SR_SUSPENDED is set and then returns. We will wait
3510 // here for a resume signal and that completes the suspend-other
3511 // action. do_suspend/do_resume is always called as a pair from
3512 // the same thread - so there are no races
3513
3514 // notify the caller
3515 osthread->sr.set_suspended();
3516
3517 sigset_t suspend_set; // signals for sigsuspend()
3518
3519 // get current set of blocked signals and unblock resume signal
3520 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3521 sigdelset(&suspend_set, SR_signum);
3522
3523 // wait here until we are resumed
3524 do {
3525 sigsuspend(&suspend_set);
3526 // ignore all returns until we get a resume signal
3527 } while (osthread->sr.suspend_action() != SR_CONTINUE);
3528
3529 resume_clear_context(osthread);
3530
3531 } else {
3532 assert(action == SR_CONTINUE, "unexpected sr action");
3533 // nothing special to do - just leave the handler
3534 }
3535
3536 errno = old_errno;
3537 }
3538
3539
3540 static int SR_initialize() {
3541 struct sigaction act;
3542 char *s;
3543 /* Get signal number to use for suspend/resume */
3544 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
3545 int sig = ::strtol(s, 0, 10);
3546 if (sig > 0 || sig < _NSIG) {
3547 SR_signum = sig;
3548 }
3549 }
3550
3551 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
3552 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
3553
3554 sigemptyset(&SR_sigset);
3555 sigaddset(&SR_sigset, SR_signum);
3556
3557 /* Set up signal handler for suspend/resume */
3558 act.sa_flags = SA_RESTART|SA_SIGINFO;
3559 act.sa_handler = (void (*)(int)) SR_handler;
3560
3561 // SR_signum is blocked by default.
3562 // 4528190 - We also need to block pthread restart signal (32 on all
3563 // supported Linux platforms). Note that LinuxThreads need to block
3564 // this signal for all threads to work properly. So we don't have
3565 // to use hard-coded signal number when setting up the mask.
3566 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
3567
3568 if (sigaction(SR_signum, &act, 0) == -1) {
3569 return -1;
3570 }
3571
3572 // Save signal flag
3573 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
3574 return 0;
3575 }
3576
3577 static int SR_finalize() {
3578 return 0;
3579 }
3580
3581
3582 // returns true on success and false on error - really an error is fatal
3583 // but this seems the normal response to library errors
3584 static bool do_suspend(OSThread* osthread) {
3585 // mark as suspended and send signal
3586 osthread->sr.set_suspend_action(SR_SUSPEND);
3587 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3588 assert_status(status == 0, status, "pthread_kill");
3589
3590 // check status and wait until notified of suspension
3591 if (status == 0) {
3592 for (int i = 0; !osthread->sr.is_suspended(); i++) {
3593 os::yield_all(i);
3594 }
3595 osthread->sr.set_suspend_action(SR_NONE);
3596 return true;
3597 }
3598 else {
3599 osthread->sr.set_suspend_action(SR_NONE);
3600 return false;
3601 }
3602 }
3603
3604 static void do_resume(OSThread* osthread) {
3605 assert(osthread->sr.is_suspended(), "thread should be suspended");
3606 osthread->sr.set_suspend_action(SR_CONTINUE);
3607
3608 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3609 assert_status(status == 0, status, "pthread_kill");
3610 // check status and wait unit notified of resumption
3611 if (status == 0) {
3612 for (int i = 0; osthread->sr.is_suspended(); i++) {
3613 os::yield_all(i);
3614 }
3615 }
3616 osthread->sr.set_suspend_action(SR_NONE);
3617 }
3618
3619 ////////////////////////////////////////////////////////////////////////////////
3620 // interrupt support
3621
3622 void os::interrupt(Thread* thread) {
3623 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3624 "possibility of dangling Thread pointer");
3625
3626 OSThread* osthread = thread->osthread();
3627
3628 if (!osthread->interrupted()) {
3629 osthread->set_interrupted(true);
3630 // More than one thread can get here with the same value of osthread,
3631 // resulting in multiple notifications. We do, however, want the store
3632 // to interrupted() to be visible to other threads before we execute unpark().
3633 OrderAccess::fence();
3634 ParkEvent * const slp = thread->_SleepEvent ;
3635 if (slp != NULL) slp->unpark() ;
3636 }
3637
3638 // For JSR166. Unpark even if interrupt status already was set
3639 if (thread->is_Java_thread())
3640 ((JavaThread*)thread)->parker()->unpark();
3641
3642 ParkEvent * ev = thread->_ParkEvent ;
3643 if (ev != NULL) ev->unpark() ;
3644
3645 }
3646
3647 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
3648 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3649 "possibility of dangling Thread pointer");
3650
3651 OSThread* osthread = thread->osthread();
3652
3653 bool interrupted = osthread->interrupted();
3654
3655 if (interrupted && clear_interrupted) {
3656 osthread->set_interrupted(false);
3657 // consider thread->_SleepEvent->reset() ... optional optimization
3658 }
3659
3660 return interrupted;
3661 }
3662
3663 ///////////////////////////////////////////////////////////////////////////////////
3664 // signal handling (except suspend/resume)
3665
3666 // This routine may be used by user applications as a "hook" to catch signals.
3667 // The user-defined signal handler must pass unrecognized signals to this
3668 // routine, and if it returns true (non-zero), then the signal handler must
3669 // return immediately. If the flag "abort_if_unrecognized" is true, then this
3670 // routine will never retun false (zero), but instead will execute a VM panic
3671 // routine kill the process.
3672 //
3673 // If this routine returns false, it is OK to call it again. This allows
3674 // the user-defined signal handler to perform checks either before or after
3675 // the VM performs its own checks. Naturally, the user code would be making
3676 // a serious error if it tried to handle an exception (such as a null check
3677 // or breakpoint) that the VM was generating for its own correct operation.
3678 //
3679 // This routine may recognize any of the following kinds of signals:
3680 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
3681 // It should be consulted by handlers for any of those signals.
3682 //
3683 // The caller of this routine must pass in the three arguments supplied
3684 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
3685 // field of the structure passed to sigaction(). This routine assumes that
3686 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
3687 //
3688 // Note that the VM will print warnings if it detects conflicting signal
3689 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
3690 //
3691 extern "C" JNIEXPORT int
3692 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
3693 void* ucontext, int abort_if_unrecognized);
3694
3695 void signalHandler(int sig, siginfo_t* info, void* uc) {
3696 assert(info != NULL && uc != NULL, "it must be old kernel");
3697 JVM_handle_linux_signal(sig, info, uc, true);
3698 }
3699
3700
3701 // This boolean allows users to forward their own non-matching signals
3702 // to JVM_handle_linux_signal, harmlessly.
3703 bool os::Linux::signal_handlers_are_installed = false;
3704
3705 // For signal-chaining
3706 struct sigaction os::Linux::sigact[MAXSIGNUM];
3707 unsigned int os::Linux::sigs = 0;
3708 bool os::Linux::libjsig_is_loaded = false;
3709 typedef struct sigaction *(*get_signal_t)(int);
3710 get_signal_t os::Linux::get_signal_action = NULL;
3711
3712 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
3713 struct sigaction *actp = NULL;
3714
3715 if (libjsig_is_loaded) {
3716 // Retrieve the old signal handler from libjsig
3717 actp = (*get_signal_action)(sig);
3718 }
3719 if (actp == NULL) {
3720 // Retrieve the preinstalled signal handler from jvm
3721 actp = get_preinstalled_handler(sig);
3722 }
3723
3724 return actp;
3725 }
3726
3727 static bool call_chained_handler(struct sigaction *actp, int sig,
3728 siginfo_t *siginfo, void *context) {
3729 // Call the old signal handler
3730 if (actp->sa_handler == SIG_DFL) {
3731 // It's more reasonable to let jvm treat it as an unexpected exception
3732 // instead of taking the default action.
3733 return false;
3734 } else if (actp->sa_handler != SIG_IGN) {
3735 if ((actp->sa_flags & SA_NODEFER) == 0) {
3736 // automaticlly block the signal
3737 sigaddset(&(actp->sa_mask), sig);
3738 }
3739
3740 sa_handler_t hand;
3741 sa_sigaction_t sa;
3742 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3743 // retrieve the chained handler
3744 if (siginfo_flag_set) {
3745 sa = actp->sa_sigaction;
3746 } else {
3747 hand = actp->sa_handler;
3748 }
3749
3750 if ((actp->sa_flags & SA_RESETHAND) != 0) {
3751 actp->sa_handler = SIG_DFL;
3752 }
3753
3754 // try to honor the signal mask
3755 sigset_t oset;
3756 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3757
3758 // call into the chained handler
3759 if (siginfo_flag_set) {
3760 (*sa)(sig, siginfo, context);
3761 } else {
3762 (*hand)(sig);
3763 }
3764
3765 // restore the signal mask
3766 pthread_sigmask(SIG_SETMASK, &oset, 0);
3767 }
3768 // Tell jvm's signal handler the signal is taken care of.
3769 return true;
3770 }
3771
3772 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3773 bool chained = false;
3774 // signal-chaining
3775 if (UseSignalChaining) {
3776 struct sigaction *actp = get_chained_signal_action(sig);
3777 if (actp != NULL) {
3778 chained = call_chained_handler(actp, sig, siginfo, context);
3779 }
3780 }
3781 return chained;
3782 }
3783
3784 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
3785 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
3786 return &sigact[sig];
3787 }
3788 return NULL;
3789 }
3790
3791 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3792 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3793 sigact[sig] = oldAct;
3794 sigs |= (unsigned int)1 << sig;
3795 }
3796
3797 // for diagnostic
3798 int os::Linux::sigflags[MAXSIGNUM];
3799
3800 int os::Linux::get_our_sigflags(int sig) {
3801 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3802 return sigflags[sig];
3803 }
3804
3805 void os::Linux::set_our_sigflags(int sig, int flags) {
3806 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3807 sigflags[sig] = flags;
3808 }
3809
3810 void os::Linux::set_signal_handler(int sig, bool set_installed) {
3811 // Check for overwrite.
3812 struct sigaction oldAct;
3813 sigaction(sig, (struct sigaction*)NULL, &oldAct);
3814
3815 void* oldhand = oldAct.sa_sigaction
3816 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3817 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3818 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3819 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3820 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3821 if (AllowUserSignalHandlers || !set_installed) {
3822 // Do not overwrite; user takes responsibility to forward to us.
3823 return;
3824 } else if (UseSignalChaining) {
3825 // save the old handler in jvm
3826 save_preinstalled_handler(sig, oldAct);
3827 // libjsig also interposes the sigaction() call below and saves the
3828 // old sigaction on it own.
3829 } else {
3830 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
3831 "%#lx for signal %d.", (long)oldhand, sig));
3832 }
3833 }
3834
3835 struct sigaction sigAct;
3836 sigfillset(&(sigAct.sa_mask));
3837 sigAct.sa_handler = SIG_DFL;
3838 if (!set_installed) {
3839 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3840 } else {
3841 sigAct.sa_sigaction = signalHandler;
3842 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3843 }
3844 // Save flags, which are set by ours
3845 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3846 sigflags[sig] = sigAct.sa_flags;
3847
3848 int ret = sigaction(sig, &sigAct, &oldAct);
3849 assert(ret == 0, "check");
3850
3851 void* oldhand2 = oldAct.sa_sigaction
3852 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3853 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3854 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3855 }
3856
3857 // install signal handlers for signals that HotSpot needs to
3858 // handle in order to support Java-level exception handling.
3859
3860 void os::Linux::install_signal_handlers() {
3861 if (!signal_handlers_are_installed) {
3862 signal_handlers_are_installed = true;
3863
3864 // signal-chaining
3865 typedef void (*signal_setting_t)();
3866 signal_setting_t begin_signal_setting = NULL;
3867 signal_setting_t end_signal_setting = NULL;
3868 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3869 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3870 if (begin_signal_setting != NULL) {
3871 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3872 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3873 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3874 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3875 libjsig_is_loaded = true;
3876 assert(UseSignalChaining, "should enable signal-chaining");
3877 }
3878 if (libjsig_is_loaded) {
3879 // Tell libjsig jvm is setting signal handlers
3880 (*begin_signal_setting)();
3881 }
3882
3883 set_signal_handler(SIGSEGV, true);
3884 set_signal_handler(SIGPIPE, true);
3885 set_signal_handler(SIGBUS, true);
3886 set_signal_handler(SIGILL, true);
3887 set_signal_handler(SIGFPE, true);
3888 set_signal_handler(SIGXFSZ, true);
3889
3890 if (libjsig_is_loaded) {
3891 // Tell libjsig jvm finishes setting signal handlers
3892 (*end_signal_setting)();
3893 }
3894
3895 // We don't activate signal checker if libjsig is in place, we trust ourselves
3896 // and if UserSignalHandler is installed all bets are off.
3897 // Log that signal checking is off only if -verbose:jni is specified.
3898 if (CheckJNICalls) {
3899 if (libjsig_is_loaded) {
3900 if (PrintJNIResolving) {
3901 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3902 }
3903 check_signals = false;
3904 }
3905 if (AllowUserSignalHandlers) {
3906 if (PrintJNIResolving) {
3907 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3908 }
3909 check_signals = false;
3910 }
3911 }
3912 }
3913 }
3914
3915 // This is the fastest way to get thread cpu time on Linux.
3916 // Returns cpu time (user+sys) for any thread, not only for current.
3917 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
3918 // It might work on 2.6.10+ with a special kernel/glibc patch.
3919 // For reference, please, see IEEE Std 1003.1-2004:
3920 // http://www.unix.org/single_unix_specification
3921
3922 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
3923 struct timespec tp;
3924 int rc = os::Linux::clock_gettime(clockid, &tp);
3925 assert(rc == 0, "clock_gettime is expected to return 0 code");
3926
3927 return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec;
3928 }
3929
3930 /////
3931 // glibc on Linux platform uses non-documented flag
3932 // to indicate, that some special sort of signal
3933 // trampoline is used.
3934 // We will never set this flag, and we should
3935 // ignore this flag in our diagnostic
3936 #ifdef SIGNIFICANT_SIGNAL_MASK
3937 #undef SIGNIFICANT_SIGNAL_MASK
3938 #endif
3939 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3940
3941 static const char* get_signal_handler_name(address handler,
3942 char* buf, int buflen) {
3943 int offset;
3944 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3945 if (found) {
3946 // skip directory names
3947 const char *p1, *p2;
3948 p1 = buf;
3949 size_t len = strlen(os::file_separator());
3950 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3951 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3952 } else {
3953 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3954 }
3955 return buf;
3956 }
3957
3958 static void print_signal_handler(outputStream* st, int sig,
3959 char* buf, size_t buflen) {
3960 struct sigaction sa;
3961
3962 sigaction(sig, NULL, &sa);
3963
3964 // See comment for SIGNIFICANT_SIGNAL_MASK define
3965 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3966
3967 st->print("%s: ", os::exception_name(sig, buf, buflen));
3968
3969 address handler = (sa.sa_flags & SA_SIGINFO)
3970 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3971 : CAST_FROM_FN_PTR(address, sa.sa_handler);
3972
3973 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3974 st->print("SIG_DFL");
3975 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3976 st->print("SIG_IGN");
3977 } else {
3978 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3979 }
3980
3981 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
3982
3983 address rh = VMError::get_resetted_sighandler(sig);
3984 // May be, handler was resetted by VMError?
3985 if(rh != NULL) {
3986 handler = rh;
3987 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3988 }
3989
3990 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
3991
3992 // Check: is it our handler?
3993 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3994 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3995 // It is our signal handler
3996 // check for flags, reset system-used one!
3997 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
3998 st->print(
3999 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4000 os::Linux::get_our_sigflags(sig));
4001 }
4002 }
4003 st->cr();
4004 }
4005
4006
4007 #define DO_SIGNAL_CHECK(sig) \
4008 if (!sigismember(&check_signal_done, sig)) \
4009 os::Linux::check_signal_handler(sig)
4010
4011 // This method is a periodic task to check for misbehaving JNI applications
4012 // under CheckJNI, we can add any periodic checks here
4013
4014 void os::run_periodic_checks() {
4015
4016 if (check_signals == false) return;
4017
4018 // SEGV and BUS if overridden could potentially prevent
4019 // generation of hs*.log in the event of a crash, debugging
4020 // such a case can be very challenging, so we absolutely
4021 // check the following for a good measure:
4022 DO_SIGNAL_CHECK(SIGSEGV);
4023 DO_SIGNAL_CHECK(SIGILL);
4024 DO_SIGNAL_CHECK(SIGFPE);
4025 DO_SIGNAL_CHECK(SIGBUS);
4026 DO_SIGNAL_CHECK(SIGPIPE);
4027 DO_SIGNAL_CHECK(SIGXFSZ);
4028
4029
4030 // ReduceSignalUsage allows the user to override these handlers
4031 // see comments at the very top and jvm_solaris.h
4032 if (!ReduceSignalUsage) {
4033 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4034 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4035 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4036 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4037 }
4038
4039 DO_SIGNAL_CHECK(SR_signum);
4040 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4041 }
4042
4043 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4044
4045 static os_sigaction_t os_sigaction = NULL;
4046
4047 void os::Linux::check_signal_handler(int sig) {
4048 char buf[O_BUFLEN];
4049 address jvmHandler = NULL;
4050
4051
4052 struct sigaction act;
4053 if (os_sigaction == NULL) {
4054 // only trust the default sigaction, in case it has been interposed
4055 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4056 if (os_sigaction == NULL) return;
4057 }
4058
4059 os_sigaction(sig, (struct sigaction*)NULL, &act);
4060
4061
4062 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4063
4064 address thisHandler = (act.sa_flags & SA_SIGINFO)
4065 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4066 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4067
4068
4069 switch(sig) {
4070 case SIGSEGV:
4071 case SIGBUS:
4072 case SIGFPE:
4073 case SIGPIPE:
4074 case SIGILL:
4075 case SIGXFSZ:
4076 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4077 break;
4078
4079 case SHUTDOWN1_SIGNAL:
4080 case SHUTDOWN2_SIGNAL:
4081 case SHUTDOWN3_SIGNAL:
4082 case BREAK_SIGNAL:
4083 jvmHandler = (address)user_handler();
4084 break;
4085
4086 case INTERRUPT_SIGNAL:
4087 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4088 break;
4089
4090 default:
4091 if (sig == SR_signum) {
4092 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4093 } else {
4094 return;
4095 }
4096 break;
4097 }
4098
4099 if (thisHandler != jvmHandler) {
4100 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4101 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4102 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4103 // No need to check this sig any longer
4104 sigaddset(&check_signal_done, sig);
4105 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4106 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4107 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4108 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4109 // No need to check this sig any longer
4110 sigaddset(&check_signal_done, sig);
4111 }
4112
4113 // Dump all the signal
4114 if (sigismember(&check_signal_done, sig)) {
4115 print_signal_handlers(tty, buf, O_BUFLEN);
4116 }
4117 }
4118
4119 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4120
4121 extern bool signal_name(int signo, char* buf, size_t len);
4122
4123 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4124 if (0 < exception_code && exception_code <= SIGRTMAX) {
4125 // signal
4126 if (!signal_name(exception_code, buf, size)) {
4127 jio_snprintf(buf, size, "SIG%d", exception_code);
4128 }
4129 return buf;
4130 } else {
4131 return NULL;
4132 }
4133 }
4134
4135 // this is called _before_ the most of global arguments have been parsed
4136 void os::init(void) {
4137 char dummy; /* used to get a guess on initial stack address */
4138 // first_hrtime = gethrtime();
4139
4140 // With LinuxThreads the JavaMain thread pid (primordial thread)
4141 // is different than the pid of the java launcher thread.
4142 // So, on Linux, the launcher thread pid is passed to the VM
4143 // via the sun.java.launcher.pid property.
4144 // Use this property instead of getpid() if it was correctly passed.
4145 // See bug 6351349.
4146 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4147
4148 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4149
4150 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4151
4152 init_random(1234567);
4153
4154 ThreadCritical::initialize();
4155
4156 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4157 if (Linux::page_size() == -1) {
4158 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4159 strerror(errno)));
4160 }
4161 init_page_sizes((size_t) Linux::page_size());
4162
4163 Linux::initialize_system_info();
4164
4165 // main_thread points to the aboriginal thread
4166 Linux::_main_thread = pthread_self();
4167
4168 Linux::clock_init();
4169 initial_time_count = os::elapsed_counter();
4170 pthread_mutex_init(&dl_mutex, NULL);
4171 }
4172
4173 // To install functions for atexit system call
4174 extern "C" {
4175 static void perfMemory_exit_helper() {
4176 perfMemory_exit();
4177 }
4178 }
4179
4180 // this is called _after_ the global arguments have been parsed
4181 jint os::init_2(void)
4182 {
4183 Linux::fast_thread_clock_init();
4184
4185 // Allocate a single page and mark it as readable for safepoint polling
4186 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4187 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4188
4189 os::set_polling_page( polling_page );
4190
4191 #ifndef PRODUCT
4192 if(Verbose && PrintMiscellaneous)
4193 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4194 #endif
4195
4196 if (!UseMembar) {
4197 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4198 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page");
4199 os::set_memory_serialize_page( mem_serialize_page );
4200
4201 #ifndef PRODUCT
4202 if(Verbose && PrintMiscellaneous)
4203 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4204 #endif
4205 }
4206
4207 os::large_page_init();
4208
4209 // initialize suspend/resume support - must do this before signal_sets_init()
4210 if (SR_initialize() != 0) {
4211 perror("SR_initialize failed");
4212 return JNI_ERR;
4213 }
4214
4215 Linux::signal_sets_init();
4216 Linux::install_signal_handlers();
4217
4218 // Check minimum allowable stack size for thread creation and to initialize
4219 // the java system classes, including StackOverflowError - depends on page
4220 // size. Add a page for compiler2 recursion in main thread.
4221 // Add in 2*BytesPerWord times page size to account for VM stack during
4222 // class initialization depending on 32 or 64 bit VM.
4223 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4224 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+
4225 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size());
4226
4227 size_t threadStackSizeInBytes = ThreadStackSize * K;
4228 if (threadStackSizeInBytes != 0 &&
4229 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4230 tty->print_cr("\nThe stack size specified is too small, "
4231 "Specify at least %dk",
4232 os::Linux::min_stack_allowed/ K);
4233 return JNI_ERR;
4234 }
4235
4236 // Make the stack size a multiple of the page size so that
4237 // the yellow/red zones can be guarded.
4238 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4239 vm_page_size()));
4240
4241 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4242
4243 Linux::libpthread_init();
4244 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4245 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4246 Linux::glibc_version(), Linux::libpthread_version(),
4247 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4248 }
4249
4250 if (UseNUMA) {
4251 if (!Linux::libnuma_init()) {
4252 UseNUMA = false;
4253 } else {
4254 if ((Linux::numa_max_node() < 1)) {
4255 // There's only one node(they start from 0), disable NUMA.
4256 UseNUMA = false;
4257 }
4258 }
4259 // With SHM large pages we cannot uncommit a page, so there's not way
4260 // we can make the adaptive lgrp chunk resizing work. If the user specified
4261 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and
4262 // disable adaptive resizing.
4263 if (UseNUMA && UseLargePages && UseSHM) {
4264 if (!FLAG_IS_DEFAULT(UseNUMA)) {
4265 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) {
4266 UseLargePages = false;
4267 } else {
4268 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing");
4269 UseAdaptiveSizePolicy = false;
4270 UseAdaptiveNUMAChunkSizing = false;
4271 }
4272 } else {
4273 UseNUMA = false;
4274 }
4275 }
4276 if (!UseNUMA && ForceNUMA) {
4277 UseNUMA = true;
4278 }
4279 }
4280
4281 if (MaxFDLimit) {
4282 // set the number of file descriptors to max. print out error
4283 // if getrlimit/setrlimit fails but continue regardless.
4284 struct rlimit nbr_files;
4285 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4286 if (status != 0) {
4287 if (PrintMiscellaneous && (Verbose || WizardMode))
4288 perror("os::init_2 getrlimit failed");
4289 } else {
4290 nbr_files.rlim_cur = nbr_files.rlim_max;
4291 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4292 if (status != 0) {
4293 if (PrintMiscellaneous && (Verbose || WizardMode))
4294 perror("os::init_2 setrlimit failed");
4295 }
4296 }
4297 }
4298
4299 // Initialize lock used to serialize thread creation (see os::create_thread)
4300 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4301
4302 // at-exit methods are called in the reverse order of their registration.
4303 // atexit functions are called on return from main or as a result of a
4304 // call to exit(3C). There can be only 32 of these functions registered
4305 // and atexit() does not set errno.
4306
4307 if (PerfAllowAtExitRegistration) {
4308 // only register atexit functions if PerfAllowAtExitRegistration is set.
4309 // atexit functions can be delayed until process exit time, which
4310 // can be problematic for embedded VM situations. Embedded VMs should
4311 // call DestroyJavaVM() to assure that VM resources are released.
4312
4313 // note: perfMemory_exit_helper atexit function may be removed in
4314 // the future if the appropriate cleanup code can be added to the
4315 // VM_Exit VMOperation's doit method.
4316 if (atexit(perfMemory_exit_helper) != 0) {
4317 warning("os::init2 atexit(perfMemory_exit_helper) failed");
4318 }
4319 }
4320
4321 // initialize thread priority policy
4322 prio_init();
4323
4324 return JNI_OK;
4325 }
4326
4327 // this is called at the end of vm_initialization
4328 void os::init_3(void)
4329 {
4330 #ifdef JAVASE_EMBEDDED
4331 // Start the MemNotifyThread
4332 if (LowMemoryProtection) {
4333 MemNotifyThread::start();
4334 }
4335 return;
4336 #endif
4337 }
4338
4339 // Mark the polling page as unreadable
4340 void os::make_polling_page_unreadable(void) {
4341 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
4342 fatal("Could not disable polling page");
4343 };
4344
4345 // Mark the polling page as readable
4346 void os::make_polling_page_readable(void) {
4347 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4348 fatal("Could not enable polling page");
4349 }
4350 };
4351
4352 int os::active_processor_count() {
4353 // Linux doesn't yet have a (official) notion of processor sets,
4354 // so just return the number of online processors.
4355 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4356 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
4357 return online_cpus;
4358 }
4359
4360 void os::set_native_thread_name(const char *name) {
4361 // Not yet implemented.
4362 return;
4363 }
4364
4365 bool os::distribute_processes(uint length, uint* distribution) {
4366 // Not yet implemented.
4367 return false;
4368 }
4369
4370 bool os::bind_to_processor(uint processor_id) {
4371 // Not yet implemented.
4372 return false;
4373 }
4374
4375 ///
4376
4377 // Suspends the target using the signal mechanism and then grabs the PC before
4378 // resuming the target. Used by the flat-profiler only
4379 ExtendedPC os::get_thread_pc(Thread* thread) {
4380 // Make sure that it is called by the watcher for the VMThread
4381 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4382 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4383
4384 ExtendedPC epc;
4385
4386 OSThread* osthread = thread->osthread();
4387 if (do_suspend(osthread)) {
4388 if (osthread->ucontext() != NULL) {
4389 epc = os::Linux::ucontext_get_pc(osthread->ucontext());
4390 } else {
4391 // NULL context is unexpected, double-check this is the VMThread
4392 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4393 }
4394 do_resume(osthread);
4395 }
4396 // failure means pthread_kill failed for some reason - arguably this is
4397 // a fatal problem, but such problems are ignored elsewhere
4398
4399 return epc;
4400 }
4401
4402 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4403 {
4404 if (is_NPTL()) {
4405 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4406 } else {
4407 #ifndef IA64
4408 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4409 // word back to default 64bit precision if condvar is signaled. Java
4410 // wants 53bit precision. Save and restore current value.
4411 int fpu = get_fpu_control_word();
4412 #endif // IA64
4413 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4414 #ifndef IA64
4415 set_fpu_control_word(fpu);
4416 #endif // IA64
4417 return status;
4418 }
4419 }
4420
4421 ////////////////////////////////////////////////////////////////////////////////
4422 // debug support
4423
4424 static address same_page(address x, address y) {
4425 int page_bits = -os::vm_page_size();
4426 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
4427 return x;
4428 else if (x > y)
4429 return (address)(intptr_t(y) | ~page_bits) + 1;
4430 else
4431 return (address)(intptr_t(y) & page_bits);
4432 }
4433
4434 bool os::find(address addr, outputStream* st) {
4435 Dl_info dlinfo;
4436 memset(&dlinfo, 0, sizeof(dlinfo));
4437 if (dladdr(addr, &dlinfo)) {
4438 st->print(PTR_FORMAT ": ", addr);
4439 if (dlinfo.dli_sname != NULL) {
4440 st->print("%s+%#x", dlinfo.dli_sname,
4441 addr - (intptr_t)dlinfo.dli_saddr);
4442 } else if (dlinfo.dli_fname) {
4443 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4444 } else {
4445 st->print("<absolute address>");
4446 }
4447 if (dlinfo.dli_fname) {
4448 st->print(" in %s", dlinfo.dli_fname);
4449 }
4450 if (dlinfo.dli_fbase) {
4451 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4452 }
4453 st->cr();
4454
4455 if (Verbose) {
4456 // decode some bytes around the PC
4457 address begin = same_page(addr-40, addr);
4458 address end = same_page(addr+40, addr);
4459 address lowest = (address) dlinfo.dli_sname;
4460 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4461 if (begin < lowest) begin = lowest;
4462 Dl_info dlinfo2;
4463 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
4464 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
4465 end = (address) dlinfo2.dli_saddr;
4466 Disassembler::decode(begin, end, st);
4467 }
4468 return true;
4469 }
4470 return false;
4471 }
4472
4473 ////////////////////////////////////////////////////////////////////////////////
4474 // misc
4475
4476 // This does not do anything on Linux. This is basically a hook for being
4477 // able to use structured exception handling (thread-local exception filters)
4478 // on, e.g., Win32.
4479 void
4480 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
4481 JavaCallArguments* args, Thread* thread) {
4482 f(value, method, args, thread);
4483 }
4484
4485 void os::print_statistics() {
4486 }
4487
4488 int os::message_box(const char* title, const char* message) {
4489 int i;
4490 fdStream err(defaultStream::error_fd());
4491 for (i = 0; i < 78; i++) err.print_raw("=");
4492 err.cr();
4493 err.print_raw_cr(title);
4494 for (i = 0; i < 78; i++) err.print_raw("-");
4495 err.cr();
4496 err.print_raw_cr(message);
4497 for (i = 0; i < 78; i++) err.print_raw("=");
4498 err.cr();
4499
4500 char buf[16];
4501 // Prevent process from exiting upon "read error" without consuming all CPU
4502 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
4503
4504 return buf[0] == 'y' || buf[0] == 'Y';
4505 }
4506
4507 int os::stat(const char *path, struct stat *sbuf) {
4508 char pathbuf[MAX_PATH];
4509 if (strlen(path) > MAX_PATH - 1) {
4510 errno = ENAMETOOLONG;
4511 return -1;
4512 }
4513 os::native_path(strcpy(pathbuf, path));
4514 return ::stat(pathbuf, sbuf);
4515 }
4516
4517 bool os::check_heap(bool force) {
4518 return true;
4519 }
4520
4521 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
4522 return ::vsnprintf(buf, count, format, args);
4523 }
4524
4525 // Is a (classpath) directory empty?
4526 bool os::dir_is_empty(const char* path) {
4527 DIR *dir = NULL;
4528 struct dirent *ptr;
4529
4530 dir = opendir(path);
4531 if (dir == NULL) return true;
4532
4533 /* Scan the directory */
4534 bool result = true;
4535 char buf[sizeof(struct dirent) + MAX_PATH];
4536 while (result && (ptr = ::readdir(dir)) != NULL) {
4537 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
4538 result = false;
4539 }
4540 }
4541 closedir(dir);
4542 return result;
4543 }
4544
4545 // This code originates from JDK's sysOpen and open64_w
4546 // from src/solaris/hpi/src/system_md.c
4547
4548 #ifndef O_DELETE
4549 #define O_DELETE 0x10000
4550 #endif
4551
4552 // Open a file. Unlink the file immediately after open returns
4553 // if the specified oflag has the O_DELETE flag set.
4554 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
4555
4556 int os::open(const char *path, int oflag, int mode) {
4557
4558 if (strlen(path) > MAX_PATH - 1) {
4559 errno = ENAMETOOLONG;
4560 return -1;
4561 }
4562 int fd;
4563 int o_delete = (oflag & O_DELETE);
4564 oflag = oflag & ~O_DELETE;
4565
4566 fd = ::open64(path, oflag, mode);
4567 if (fd == -1) return -1;
4568
4569 //If the open succeeded, the file might still be a directory
4570 {
4571 struct stat64 buf64;
4572 int ret = ::fstat64(fd, &buf64);
4573 int st_mode = buf64.st_mode;
4574
4575 if (ret != -1) {
4576 if ((st_mode & S_IFMT) == S_IFDIR) {
4577 errno = EISDIR;
4578 ::close(fd);
4579 return -1;
4580 }
4581 } else {
4582 ::close(fd);
4583 return -1;
4584 }
4585 }
4586
4587 /*
4588 * All file descriptors that are opened in the JVM and not
4589 * specifically destined for a subprocess should have the
4590 * close-on-exec flag set. If we don't set it, then careless 3rd
4591 * party native code might fork and exec without closing all
4592 * appropriate file descriptors (e.g. as we do in closeDescriptors in
4593 * UNIXProcess.c), and this in turn might:
4594 *
4595 * - cause end-of-file to fail to be detected on some file
4596 * descriptors, resulting in mysterious hangs, or
4597 *
4598 * - might cause an fopen in the subprocess to fail on a system
4599 * suffering from bug 1085341.
4600 *
4601 * (Yes, the default setting of the close-on-exec flag is a Unix
4602 * design flaw)
4603 *
4604 * See:
4605 * 1085341: 32-bit stdio routines should support file descriptors >255
4606 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
4607 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
4608 */
4609 #ifdef FD_CLOEXEC
4610 {
4611 int flags = ::fcntl(fd, F_GETFD);
4612 if (flags != -1)
4613 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
4614 }
4615 #endif
4616
4617 if (o_delete != 0) {
4618 ::unlink(path);
4619 }
4620 return fd;
4621 }
4622
4623
4624 // create binary file, rewriting existing file if required
4625 int os::create_binary_file(const char* path, bool rewrite_existing) {
4626 int oflags = O_WRONLY | O_CREAT;
4627 if (!rewrite_existing) {
4628 oflags |= O_EXCL;
4629 }
4630 return ::open64(path, oflags, S_IREAD | S_IWRITE);
4631 }
4632
4633 // return current position of file pointer
4634 jlong os::current_file_offset(int fd) {
4635 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
4636 }
4637
4638 // move file pointer to the specified offset
4639 jlong os::seek_to_file_offset(int fd, jlong offset) {
4640 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
4641 }
4642
4643 // This code originates from JDK's sysAvailable
4644 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
4645
4646 int os::available(int fd, jlong *bytes) {
4647 jlong cur, end;
4648 int mode;
4649 struct stat64 buf64;
4650
4651 if (::fstat64(fd, &buf64) >= 0) {
4652 mode = buf64.st_mode;
4653 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
4654 /*
4655 * XXX: is the following call interruptible? If so, this might
4656 * need to go through the INTERRUPT_IO() wrapper as for other
4657 * blocking, interruptible calls in this file.
4658 */
4659 int n;
4660 if (::ioctl(fd, FIONREAD, &n) >= 0) {
4661 *bytes = n;
4662 return 1;
4663 }
4664 }
4665 }
4666 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
4667 return 0;
4668 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
4669 return 0;
4670 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
4671 return 0;
4672 }
4673 *bytes = end - cur;
4674 return 1;
4675 }
4676
4677 int os::socket_available(int fd, jint *pbytes) {
4678 // Linux doc says EINTR not returned, unlike Solaris
4679 int ret = ::ioctl(fd, FIONREAD, pbytes);
4680
4681 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
4682 // is expected to return 0 on failure and 1 on success to the jdk.
4683 return (ret < 0) ? 0 : 1;
4684 }
4685
4686 // Map a block of memory.
4687 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
4688 char *addr, size_t bytes, bool read_only,
4689 bool allow_exec) {
4690 int prot;
4691 int flags;
4692
4693 if (read_only) {
4694 prot = PROT_READ;
4695 flags = MAP_SHARED;
4696 } else {
4697 prot = PROT_READ | PROT_WRITE;
4698 flags = MAP_PRIVATE;
4699 }
4700
4701 if (allow_exec) {
4702 prot |= PROT_EXEC;
4703 }
4704
4705 if (addr != NULL) {
4706 flags |= MAP_FIXED;
4707 }
4708
4709 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
4710 fd, file_offset);
4711 if (mapped_address == MAP_FAILED) {
4712 return NULL;
4713 }
4714 return mapped_address;
4715 }
4716
4717
4718 // Remap a block of memory.
4719 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
4720 char *addr, size_t bytes, bool read_only,
4721 bool allow_exec) {
4722 // same as map_memory() on this OS
4723 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4724 allow_exec);
4725 }
4726
4727
4728 // Unmap a block of memory.
4729 bool os::unmap_memory(char* addr, size_t bytes) {
4730 return munmap(addr, bytes) == 0;
4731 }
4732
4733 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
4734
4735 static clockid_t thread_cpu_clockid(Thread* thread) {
4736 pthread_t tid = thread->osthread()->pthread_id();
4737 clockid_t clockid;
4738
4739 // Get thread clockid
4740 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
4741 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
4742 return clockid;
4743 }
4744
4745 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4746 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4747 // of a thread.
4748 //
4749 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4750 // the fast estimate available on the platform.
4751
4752 jlong os::current_thread_cpu_time() {
4753 if (os::Linux::supports_fast_thread_cpu_time()) {
4754 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4755 } else {
4756 // return user + sys since the cost is the same
4757 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
4758 }
4759 }
4760
4761 jlong os::thread_cpu_time(Thread* thread) {
4762 // consistent with what current_thread_cpu_time() returns
4763 if (os::Linux::supports_fast_thread_cpu_time()) {
4764 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4765 } else {
4766 return slow_thread_cpu_time(thread, true /* user + sys */);
4767 }
4768 }
4769
4770 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4771 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4772 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4773 } else {
4774 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
4775 }
4776 }
4777
4778 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4779 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4780 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4781 } else {
4782 return slow_thread_cpu_time(thread, user_sys_cpu_time);
4783 }
4784 }
4785
4786 //
4787 // -1 on error.
4788 //
4789
4790 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4791 static bool proc_pid_cpu_avail = true;
4792 static bool proc_task_unchecked = true;
4793 static const char *proc_stat_path = "/proc/%d/stat";
4794 pid_t tid = thread->osthread()->thread_id();
4795 int i;
4796 char *s;
4797 char stat[2048];
4798 int statlen;
4799 char proc_name[64];
4800 int count;
4801 long sys_time, user_time;
4802 char string[64];
4803 char cdummy;
4804 int idummy;
4805 long ldummy;
4806 FILE *fp;
4807
4808 // We first try accessing /proc/<pid>/cpu since this is faster to
4809 // process. If this file is not present (linux kernels 2.5 and above)
4810 // then we open /proc/<pid>/stat.
4811 if ( proc_pid_cpu_avail ) {
4812 sprintf(proc_name, "/proc/%d/cpu", tid);
4813 fp = fopen(proc_name, "r");
4814 if ( fp != NULL ) {
4815 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
4816 fclose(fp);
4817 if ( count != 3 ) return -1;
4818
4819 if (user_sys_cpu_time) {
4820 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4821 } else {
4822 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4823 }
4824 }
4825 else proc_pid_cpu_avail = false;
4826 }
4827
4828 // The /proc/<tid>/stat aggregates per-process usage on
4829 // new Linux kernels 2.6+ where NPTL is supported.
4830 // The /proc/self/task/<tid>/stat still has the per-thread usage.
4831 // See bug 6328462.
4832 // There can be no directory /proc/self/task on kernels 2.4 with NPTL
4833 // and possibly in some other cases, so we check its availability.
4834 if (proc_task_unchecked && os::Linux::is_NPTL()) {
4835 // This is executed only once
4836 proc_task_unchecked = false;
4837 fp = fopen("/proc/self/task", "r");
4838 if (fp != NULL) {
4839 proc_stat_path = "/proc/self/task/%d/stat";
4840 fclose(fp);
4841 }
4842 }
4843
4844 sprintf(proc_name, proc_stat_path, tid);
4845 fp = fopen(proc_name, "r");
4846 if ( fp == NULL ) return -1;
4847 statlen = fread(stat, 1, 2047, fp);
4848 stat[statlen] = '\0';
4849 fclose(fp);
4850
4851 // Skip pid and the command string. Note that we could be dealing with
4852 // weird command names, e.g. user could decide to rename java launcher
4853 // to "java 1.4.2 :)", then the stat file would look like
4854 // 1234 (java 1.4.2 :)) R ... ...
4855 // We don't really need to know the command string, just find the last
4856 // occurrence of ")" and then start parsing from there. See bug 4726580.
4857 s = strrchr(stat, ')');
4858 i = 0;
4859 if (s == NULL ) return -1;
4860
4861 // Skip blank chars
4862 do s++; while (isspace(*s));
4863
4864 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
4865 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
4866 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
4867 &user_time, &sys_time);
4868 if ( count != 13 ) return -1;
4869 if (user_sys_cpu_time) {
4870 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4871 } else {
4872 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4873 }
4874 }
4875
4876 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4877 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4878 info_ptr->may_skip_backward = false; // elapsed time not wall time
4879 info_ptr->may_skip_forward = false; // elapsed time not wall time
4880 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4881 }
4882
4883 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4884 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4885 info_ptr->may_skip_backward = false; // elapsed time not wall time
4886 info_ptr->may_skip_forward = false; // elapsed time not wall time
4887 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4888 }
4889
4890 bool os::is_thread_cpu_time_supported() {
4891 return true;
4892 }
4893
4894 // System loadavg support. Returns -1 if load average cannot be obtained.
4895 // Linux doesn't yet have a (official) notion of processor sets,
4896 // so just return the system wide load average.
4897 int os::loadavg(double loadavg[], int nelem) {
4898 return ::getloadavg(loadavg, nelem);
4899 }
4900
4901 void os::pause() {
4902 char filename[MAX_PATH];
4903 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4904 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4905 } else {
4906 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4907 }
4908
4909 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4910 if (fd != -1) {
4911 struct stat buf;
4912 ::close(fd);
4913 while (::stat(filename, &buf) == 0) {
4914 (void)::poll(NULL, 0, 100);
4915 }
4916 } else {
4917 jio_fprintf(stderr,
4918 "Could not open pause file '%s', continuing immediately.\n", filename);
4919 }
4920 }
4921
4922
4923 // Refer to the comments in os_solaris.cpp park-unpark.
4924 //
4925 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4926 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4927 // For specifics regarding the bug see GLIBC BUGID 261237 :
4928 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4929 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4930 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4931 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
4932 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4933 // and monitorenter when we're using 1-0 locking. All those operations may result in
4934 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
4935 // of libpthread avoids the problem, but isn't practical.
4936 //
4937 // Possible remedies:
4938 //
4939 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
4940 // This is palliative and probabilistic, however. If the thread is preempted
4941 // between the call to compute_abstime() and pthread_cond_timedwait(), more
4942 // than the minimum period may have passed, and the abstime may be stale (in the
4943 // past) resultin in a hang. Using this technique reduces the odds of a hang
4944 // but the JVM is still vulnerable, particularly on heavily loaded systems.
4945 //
4946 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4947 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
4948 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4949 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
4950 // thread.
4951 //
4952 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
4953 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
4954 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
4955 // This also works well. In fact it avoids kernel-level scalability impediments
4956 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
4957 // timers in a graceful fashion.
4958 //
4959 // 4. When the abstime value is in the past it appears that control returns
4960 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4961 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
4962 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
4963 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
4964 // It may be possible to avoid reinitialization by checking the return
4965 // value from pthread_cond_timedwait(). In addition to reinitializing the
4966 // condvar we must establish the invariant that cond_signal() is only called
4967 // within critical sections protected by the adjunct mutex. This prevents
4968 // cond_signal() from "seeing" a condvar that's in the midst of being
4969 // reinitialized or that is corrupt. Sadly, this invariant obviates the
4970 // desirable signal-after-unlock optimization that avoids futile context switching.
4971 //
4972 // I'm also concerned that some versions of NTPL might allocate an auxilliary
4973 // structure when a condvar is used or initialized. cond_destroy() would
4974 // release the helper structure. Our reinitialize-after-timedwait fix
4975 // put excessive stress on malloc/free and locks protecting the c-heap.
4976 //
4977 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
4978 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4979 // and only enabling the work-around for vulnerable environments.
4980
4981 // utility to compute the abstime argument to timedwait:
4982 // millis is the relative timeout time
4983 // abstime will be the absolute timeout time
4984 // TODO: replace compute_abstime() with unpackTime()
4985
4986 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
4987 if (millis < 0) millis = 0;
4988 struct timeval now;
4989 int status = gettimeofday(&now, NULL);
4990 assert(status == 0, "gettimeofday");
4991 jlong seconds = millis / 1000;
4992 millis %= 1000;
4993 if (seconds > 50000000) { // see man cond_timedwait(3T)
4994 seconds = 50000000;
4995 }
4996 abstime->tv_sec = now.tv_sec + seconds;
4997 long usec = now.tv_usec + millis * 1000;
4998 if (usec >= 1000000) {
4999 abstime->tv_sec += 1;
5000 usec -= 1000000;
5001 }
5002 abstime->tv_nsec = usec * 1000;
5003 return abstime;
5004 }
5005
5006
5007 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
5008 // Conceptually TryPark() should be equivalent to park(0).
5009
5010 int os::PlatformEvent::TryPark() {
5011 for (;;) {
5012 const int v = _Event ;
5013 guarantee ((v == 0) || (v == 1), "invariant") ;
5014 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
5015 }
5016 }
5017
5018 void os::PlatformEvent::park() { // AKA "down()"
5019 // Invariant: Only the thread associated with the Event/PlatformEvent
5020 // may call park().
5021 // TODO: assert that _Assoc != NULL or _Assoc == Self
5022 int v ;
5023 for (;;) {
5024 v = _Event ;
5025 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5026 }
5027 guarantee (v >= 0, "invariant") ;
5028 if (v == 0) {
5029 // Do this the hard way by blocking ...
5030 int status = pthread_mutex_lock(_mutex);
5031 assert_status(status == 0, status, "mutex_lock");
5032 guarantee (_nParked == 0, "invariant") ;
5033 ++ _nParked ;
5034 while (_Event < 0) {
5035 status = pthread_cond_wait(_cond, _mutex);
5036 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5037 // Treat this the same as if the wait was interrupted
5038 if (status == ETIME) { status = EINTR; }
5039 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5040 }
5041 -- _nParked ;
5042
5043 // In theory we could move the ST of 0 into _Event past the unlock(),
5044 // but then we'd need a MEMBAR after the ST.
5045 _Event = 0 ;
5046 status = pthread_mutex_unlock(_mutex);
5047 assert_status(status == 0, status, "mutex_unlock");
5048 }
5049 guarantee (_Event >= 0, "invariant") ;
5050 }
5051
5052 int os::PlatformEvent::park(jlong millis) {
5053 guarantee (_nParked == 0, "invariant") ;
5054
5055 int v ;
5056 for (;;) {
5057 v = _Event ;
5058 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5059 }
5060 guarantee (v >= 0, "invariant") ;
5061 if (v != 0) return OS_OK ;
5062
5063 // We do this the hard way, by blocking the thread.
5064 // Consider enforcing a minimum timeout value.
5065 struct timespec abst;
5066 compute_abstime(&abst, millis);
5067
5068 int ret = OS_TIMEOUT;
5069 int status = pthread_mutex_lock(_mutex);
5070 assert_status(status == 0, status, "mutex_lock");
5071 guarantee (_nParked == 0, "invariant") ;
5072 ++_nParked ;
5073
5074 // Object.wait(timo) will return because of
5075 // (a) notification
5076 // (b) timeout
5077 // (c) thread.interrupt
5078 //
5079 // Thread.interrupt and object.notify{All} both call Event::set.
5080 // That is, we treat thread.interrupt as a special case of notification.
5081 // The underlying Solaris implementation, cond_timedwait, admits
5082 // spurious/premature wakeups, but the JLS/JVM spec prevents the
5083 // JVM from making those visible to Java code. As such, we must
5084 // filter out spurious wakeups. We assume all ETIME returns are valid.
5085 //
5086 // TODO: properly differentiate simultaneous notify+interrupt.
5087 // In that case, we should propagate the notify to another waiter.
5088
5089 while (_Event < 0) {
5090 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
5091 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5092 pthread_cond_destroy (_cond);
5093 pthread_cond_init (_cond, NULL) ;
5094 }
5095 assert_status(status == 0 || status == EINTR ||
5096 status == ETIME || status == ETIMEDOUT,
5097 status, "cond_timedwait");
5098 if (!FilterSpuriousWakeups) break ; // previous semantics
5099 if (status == ETIME || status == ETIMEDOUT) break ;
5100 // We consume and ignore EINTR and spurious wakeups.
5101 }
5102 --_nParked ;
5103 if (_Event >= 0) {
5104 ret = OS_OK;
5105 }
5106 _Event = 0 ;
5107 status = pthread_mutex_unlock(_mutex);
5108 assert_status(status == 0, status, "mutex_unlock");
5109 assert (_nParked == 0, "invariant") ;
5110 return ret;
5111 }
5112
5113 void os::PlatformEvent::unpark() {
5114 int v, AnyWaiters ;
5115 for (;;) {
5116 v = _Event ;
5117 if (v > 0) {
5118 // The LD of _Event could have reordered or be satisfied
5119 // by a read-aside from this processor's write buffer.
5120 // To avoid problems execute a barrier and then
5121 // ratify the value.
5122 OrderAccess::fence() ;
5123 if (_Event == v) return ;
5124 continue ;
5125 }
5126 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
5127 }
5128 if (v < 0) {
5129 // Wait for the thread associated with the event to vacate
5130 int status = pthread_mutex_lock(_mutex);
5131 assert_status(status == 0, status, "mutex_lock");
5132 AnyWaiters = _nParked ;
5133 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ;
5134 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5135 AnyWaiters = 0 ;
5136 pthread_cond_signal (_cond);
5137 }
5138 status = pthread_mutex_unlock(_mutex);
5139 assert_status(status == 0, status, "mutex_unlock");
5140 if (AnyWaiters != 0) {
5141 status = pthread_cond_signal(_cond);
5142 assert_status(status == 0, status, "cond_signal");
5143 }
5144 }
5145
5146 // Note that we signal() _after dropping the lock for "immortal" Events.
5147 // This is safe and avoids a common class of futile wakeups. In rare
5148 // circumstances this can cause a thread to return prematurely from
5149 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5150 // simply re-test the condition and re-park itself.
5151 }
5152
5153
5154 // JSR166
5155 // -------------------------------------------------------
5156
5157 /*
5158 * The solaris and linux implementations of park/unpark are fairly
5159 * conservative for now, but can be improved. They currently use a
5160 * mutex/condvar pair, plus a a count.
5161 * Park decrements count if > 0, else does a condvar wait. Unpark
5162 * sets count to 1 and signals condvar. Only one thread ever waits
5163 * on the condvar. Contention seen when trying to park implies that someone
5164 * is unparking you, so don't wait. And spurious returns are fine, so there
5165 * is no need to track notifications.
5166 */
5167
5168
5169 #define NANOSECS_PER_SEC 1000000000
5170 #define NANOSECS_PER_MILLISEC 1000000
5171 #define MAX_SECS 100000000
5172 /*
5173 * This code is common to linux and solaris and will be moved to a
5174 * common place in dolphin.
5175 *
5176 * The passed in time value is either a relative time in nanoseconds
5177 * or an absolute time in milliseconds. Either way it has to be unpacked
5178 * into suitable seconds and nanoseconds components and stored in the
5179 * given timespec structure.
5180 * Given time is a 64-bit value and the time_t used in the timespec is only
5181 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5182 * overflow if times way in the future are given. Further on Solaris versions
5183 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5184 * number of seconds, in abstime, is less than current_time + 100,000,000.
5185 * As it will be 28 years before "now + 100000000" will overflow we can
5186 * ignore overflow and just impose a hard-limit on seconds using the value
5187 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5188 * years from "now".
5189 */
5190
5191 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5192 assert (time > 0, "convertTime");
5193
5194 struct timeval now;
5195 int status = gettimeofday(&now, NULL);
5196 assert(status == 0, "gettimeofday");
5197
5198 time_t max_secs = now.tv_sec + MAX_SECS;
5199
5200 if (isAbsolute) {
5201 jlong secs = time / 1000;
5202 if (secs > max_secs) {
5203 absTime->tv_sec = max_secs;
5204 }
5205 else {
5206 absTime->tv_sec = secs;
5207 }
5208 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5209 }
5210 else {
5211 jlong secs = time / NANOSECS_PER_SEC;
5212 if (secs >= MAX_SECS) {
5213 absTime->tv_sec = max_secs;
5214 absTime->tv_nsec = 0;
5215 }
5216 else {
5217 absTime->tv_sec = now.tv_sec + secs;
5218 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5219 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5220 absTime->tv_nsec -= NANOSECS_PER_SEC;
5221 ++absTime->tv_sec; // note: this must be <= max_secs
5222 }
5223 }
5224 }
5225 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5226 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5227 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5228 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5229 }
5230
5231 void Parker::park(bool isAbsolute, jlong time) {
5232 // Optional fast-path check:
5233 // Return immediately if a permit is available.
5234 if (_counter > 0) {
5235 _counter = 0 ;
5236 OrderAccess::fence();
5237 return ;
5238 }
5239
5240 Thread* thread = Thread::current();
5241 assert(thread->is_Java_thread(), "Must be JavaThread");
5242 JavaThread *jt = (JavaThread *)thread;
5243
5244 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5245 // Check interrupt before trying to wait
5246 if (Thread::is_interrupted(thread, false)) {
5247 return;
5248 }
5249
5250 // Next, demultiplex/decode time arguments
5251 timespec absTime;
5252 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
5253 return;
5254 }
5255 if (time > 0) {
5256 unpackTime(&absTime, isAbsolute, time);
5257 }
5258
5259
5260 // Enter safepoint region
5261 // Beware of deadlocks such as 6317397.
5262 // The per-thread Parker:: mutex is a classic leaf-lock.
5263 // In particular a thread must never block on the Threads_lock while
5264 // holding the Parker:: mutex. If safepoints are pending both the
5265 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5266 ThreadBlockInVM tbivm(jt);
5267
5268 // Don't wait if cannot get lock since interference arises from
5269 // unblocking. Also. check interrupt before trying wait
5270 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5271 return;
5272 }
5273
5274 int status ;
5275 if (_counter > 0) { // no wait needed
5276 _counter = 0;
5277 status = pthread_mutex_unlock(_mutex);
5278 assert (status == 0, "invariant") ;
5279 OrderAccess::fence();
5280 return;
5281 }
5282
5283 #ifdef ASSERT
5284 // Don't catch signals while blocked; let the running threads have the signals.
5285 // (This allows a debugger to break into the running thread.)
5286 sigset_t oldsigs;
5287 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5288 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5289 #endif
5290
5291 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5292 jt->set_suspend_equivalent();
5293 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5294
5295 if (time == 0) {
5296 status = pthread_cond_wait (_cond, _mutex) ;
5297 } else {
5298 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
5299 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5300 pthread_cond_destroy (_cond) ;
5301 pthread_cond_init (_cond, NULL);
5302 }
5303 }
5304 assert_status(status == 0 || status == EINTR ||
5305 status == ETIME || status == ETIMEDOUT,
5306 status, "cond_timedwait");
5307
5308 #ifdef ASSERT
5309 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5310 #endif
5311
5312 _counter = 0 ;
5313 status = pthread_mutex_unlock(_mutex) ;
5314 assert_status(status == 0, status, "invariant") ;
5315 // If externally suspended while waiting, re-suspend
5316 if (jt->handle_special_suspend_equivalent_condition()) {
5317 jt->java_suspend_self();
5318 }
5319
5320 OrderAccess::fence();
5321 }
5322
5323 void Parker::unpark() {
5324 int s, status ;
5325 status = pthread_mutex_lock(_mutex);
5326 assert (status == 0, "invariant") ;
5327 s = _counter;
5328 _counter = 1;
5329 if (s < 1) {
5330 if (WorkAroundNPTLTimedWaitHang) {
5331 status = pthread_cond_signal (_cond) ;
5332 assert (status == 0, "invariant") ;
5333 status = pthread_mutex_unlock(_mutex);
5334 assert (status == 0, "invariant") ;
5335 } else {
5336 status = pthread_mutex_unlock(_mutex);
5337 assert (status == 0, "invariant") ;
5338 status = pthread_cond_signal (_cond) ;
5339 assert (status == 0, "invariant") ;
5340 }
5341 } else {
5342 pthread_mutex_unlock(_mutex);
5343 assert (status == 0, "invariant") ;
5344 }
5345 }
5346
5347
5348 extern char** environ;
5349
5350 #ifndef __NR_fork
5351 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
5352 #endif
5353
5354 #ifndef __NR_execve
5355 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
5356 #endif
5357
5358 // Run the specified command in a separate process. Return its exit value,
5359 // or -1 on failure (e.g. can't fork a new process).
5360 // Unlike system(), this function can be called from signal handler. It
5361 // doesn't block SIGINT et al.
5362 int os::fork_and_exec(char* cmd) {
5363 const char * argv[4] = {"sh", "-c", cmd, NULL};
5364
5365 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
5366 // pthread_atfork handlers and reset pthread library. All we need is a
5367 // separate process to execve. Make a direct syscall to fork process.
5368 // On IA64 there's no fork syscall, we have to use fork() and hope for
5369 // the best...
5370 pid_t pid = NOT_IA64(syscall(__NR_fork);)
5371 IA64_ONLY(fork();)
5372
5373 if (pid < 0) {
5374 // fork failed
5375 return -1;
5376
5377 } else if (pid == 0) {
5378 // child process
5379
5380 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
5381 // first to kill every thread on the thread list. Because this list is
5382 // not reset by fork() (see notes above), execve() will instead kill
5383 // every thread in the parent process. We know this is the only thread
5384 // in the new process, so make a system call directly.
5385 // IA64 should use normal execve() from glibc to match the glibc fork()
5386 // above.
5387 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
5388 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
5389
5390 // execve failed
5391 _exit(-1);
5392
5393 } else {
5394 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5395 // care about the actual exit code, for now.
5396
5397 int status;
5398
5399 // Wait for the child process to exit. This returns immediately if
5400 // the child has already exited. */
5401 while (waitpid(pid, &status, 0) < 0) {
5402 switch (errno) {
5403 case ECHILD: return 0;
5404 case EINTR: break;
5405 default: return -1;
5406 }
5407 }
5408
5409 if (WIFEXITED(status)) {
5410 // The child exited normally; get its exit code.
5411 return WEXITSTATUS(status);
5412 } else if (WIFSIGNALED(status)) {
5413 // The child exited because of a signal
5414 // The best value to return is 0x80 + signal number,
5415 // because that is what all Unix shells do, and because
5416 // it allows callers to distinguish between process exit and
5417 // process death by signal.
5418 return 0x80 + WTERMSIG(status);
5419 } else {
5420 // Unknown exit code; pass it through
5421 return status;
5422 }
5423 }
5424 }
5425
5426 // is_headless_jre()
5427 //
5428 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5429 // in order to report if we are running in a headless jre
5430 //
5431 // Since JDK8 xawt/libmawt.so was moved into the same directory
5432 // as libawt.so, and renamed libawt_xawt.so
5433 //
5434 bool os::is_headless_jre() {
5435 struct stat statbuf;
5436 char buf[MAXPATHLEN];
5437 char libmawtpath[MAXPATHLEN];
5438 const char *xawtstr = "/xawt/libmawt.so";
5439 const char *new_xawtstr = "/libawt_xawt.so";
5440 char *p;
5441
5442 // Get path to libjvm.so
5443 os::jvm_path(buf, sizeof(buf));
5444
5445 // Get rid of libjvm.so
5446 p = strrchr(buf, '/');
5447 if (p == NULL) return false;
5448 else *p = '\0';
5449
5450 // Get rid of client or server
5451 p = strrchr(buf, '/');
5452 if (p == NULL) return false;
5453 else *p = '\0';
5454
5455 // check xawt/libmawt.so
5456 strcpy(libmawtpath, buf);
5457 strcat(libmawtpath, xawtstr);
5458 if (::stat(libmawtpath, &statbuf) == 0) return false;
5459
5460 // check libawt_xawt.so
5461 strcpy(libmawtpath, buf);
5462 strcat(libmawtpath, new_xawtstr);
5463 if (::stat(libmawtpath, &statbuf) == 0) return false;
5464
5465 return true;
5466 }
5467
5468
5469 #ifdef JAVASE_EMBEDDED
5470 //
5471 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory.
5472 //
5473 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL;
5474
5475 // ctor
5476 //
5477 MemNotifyThread::MemNotifyThread(int fd): Thread() {
5478 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread");
5479 _fd = fd;
5480
5481 if (os::create_thread(this, os::os_thread)) {
5482 _memnotify_thread = this;
5483 os::set_priority(this, NearMaxPriority);
5484 os::start_thread(this);
5485 }
5486 }
5487
5488 // Where all the work gets done
5489 //
5490 void MemNotifyThread::run() {
5491 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread");
5492
5493 // Set up the select arguments
5494 fd_set rfds;
5495 if (_fd != -1) {
5496 FD_ZERO(&rfds);
5497 FD_SET(_fd, &rfds);
5498 }
5499
5500 // Now wait for the mem_notify device to wake up
5501 while (1) {
5502 // Wait for the mem_notify device to signal us..
5503 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL);
5504 if (rc == -1) {
5505 perror("select!\n");
5506 break;
5507 } else if (rc) {
5508 //ssize_t free_before = os::available_memory();
5509 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024);
5510
5511 // The kernel is telling us there is not much memory left...
5512 // try to do something about that
5513
5514 // If we are not already in a GC, try one.
5515 if (!Universe::heap()->is_gc_active()) {
5516 Universe::heap()->collect(GCCause::_allocation_failure);
5517
5518 //ssize_t free_after = os::available_memory();
5519 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024);
5520 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024);
5521 }
5522 // We might want to do something like the following if we find the GC's are not helping...
5523 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true);
5524 }
5525 }
5526 }
5527
5528 //
5529 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it.
5530 //
5531 void MemNotifyThread::start() {
5532 int fd;
5533 fd = open ("/dev/mem_notify", O_RDONLY, 0);
5534 if (fd < 0) {
5535 return;
5536 }
5537
5538 if (memnotify_thread() == NULL) {
5539 new MemNotifyThread(fd);
5540 }
5541 }
5542 #endif // JAVASE_EMBEDDED