1 /*
2 * Copyright 1999-2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 # define __STDC_FORMAT_MACROS
26
27 // do not include precompiled header file
28 # include "incls/_os_linux.cpp.incl"
29
30 // put OS-includes here
31 # include <sys/types.h>
32 # include <sys/mman.h>
33 # include <pthread.h>
34 # include <signal.h>
35 # include <errno.h>
36 # include <dlfcn.h>
37 # include <stdio.h>
38 # include <unistd.h>
39 # include <sys/resource.h>
40 # include <pthread.h>
41 # include <sys/stat.h>
42 # include <sys/time.h>
43 # include <sys/times.h>
44 # include <sys/utsname.h>
45 # include <sys/socket.h>
46 # include <sys/wait.h>
47 # include <pwd.h>
48 # include <poll.h>
49 # include <semaphore.h>
50 # include <fcntl.h>
51 # include <string.h>
52 # include <syscall.h>
53 # include <sys/sysinfo.h>
54 # include <gnu/libc-version.h>
55 # include <sys/ipc.h>
56 # include <sys/shm.h>
57 # include <link.h>
58 # include <stdint.h>
59 # include <inttypes.h>
60
61 #define MAX_PATH (2 * K)
62
63 // for timer info max values which include all bits
64 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
65 #define SEC_IN_NANOSECS 1000000000LL
66
67 ////////////////////////////////////////////////////////////////////////////////
68 // global variables
69 julong os::Linux::_physical_memory = 0;
70
71 address os::Linux::_initial_thread_stack_bottom = NULL;
72 uintptr_t os::Linux::_initial_thread_stack_size = 0;
73
74 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
75 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
76 Mutex* os::Linux::_createThread_lock = NULL;
77 pthread_t os::Linux::_main_thread;
78 int os::Linux::_page_size = -1;
79 bool os::Linux::_is_floating_stack = false;
80 bool os::Linux::_is_NPTL = false;
81 bool os::Linux::_supports_fast_thread_cpu_time = false;
82 const char * os::Linux::_glibc_version = NULL;
83 const char * os::Linux::_libpthread_version = NULL;
84
85 static jlong initial_time_count=0;
86
87 static int clock_tics_per_sec = 100;
88
89 // For diagnostics to print a message once. see run_periodic_checks
90 static sigset_t check_signal_done;
91 static bool check_signals = true;;
92
93 static pid_t _initial_pid = 0;
94
95 /* Signal number used to suspend/resume a thread */
96
97 /* do not use any signal number less than SIGSEGV, see 4355769 */
98 static int SR_signum = SIGUSR2;
99 sigset_t SR_sigset;
100
101 /* Used to protect dlsym() calls */
102 static pthread_mutex_t dl_mutex;
103
104 ////////////////////////////////////////////////////////////////////////////////
105 // utility functions
106
107 static int SR_initialize();
108 static int SR_finalize();
109
110 julong os::available_memory() {
111 return Linux::available_memory();
112 }
113
114 julong os::Linux::available_memory() {
115 // values in struct sysinfo are "unsigned long"
116 struct sysinfo si;
117 sysinfo(&si);
118
119 return (julong)si.freeram * si.mem_unit;
120 }
121
122 julong os::physical_memory() {
123 return Linux::physical_memory();
124 }
125
126 julong os::allocatable_physical_memory(julong size) {
127 #ifdef _LP64
128 return size;
129 #else
130 julong result = MIN2(size, (julong)3800*M);
131 if (!is_allocatable(result)) {
132 // See comments under solaris for alignment considerations
133 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
134 result = MIN2(size, reasonable_size);
135 }
136 return result;
137 #endif // _LP64
138 }
139
140 ////////////////////////////////////////////////////////////////////////////////
141 // environment support
142
143 bool os::getenv(const char* name, char* buf, int len) {
144 const char* val = ::getenv(name);
145 if (val != NULL && strlen(val) < (size_t)len) {
146 strcpy(buf, val);
147 return true;
148 }
149 if (len > 0) buf[0] = 0; // return a null string
150 return false;
151 }
152
153
154 // Return true if user is running as root.
155
156 bool os::have_special_privileges() {
157 static bool init = false;
158 static bool privileges = false;
159 if (!init) {
160 privileges = (getuid() != geteuid()) || (getgid() != getegid());
161 init = true;
162 }
163 return privileges;
164 }
165
166
167 #ifndef SYS_gettid
168 // i386: 224, ia64: 1105, amd64: 186, sparc 143
169 #ifdef __ia64__
170 #define SYS_gettid 1105
171 #elif __i386__
172 #define SYS_gettid 224
173 #elif __amd64__
174 #define SYS_gettid 186
175 #elif __sparc__
176 #define SYS_gettid 143
177 #else
178 #error define gettid for the arch
179 #endif
180 #endif
181
182 // Cpu architecture string
183 #if defined(ZERO)
184 static char cpu_arch[] = ZERO_LIBARCH;
185 #elif defined(IA64)
186 static char cpu_arch[] = "ia64";
187 #elif defined(IA32)
188 static char cpu_arch[] = "i386";
189 #elif defined(AMD64)
190 static char cpu_arch[] = "amd64";
191 #elif defined(SPARC)
192 # ifdef _LP64
193 static char cpu_arch[] = "sparcv9";
194 # else
195 static char cpu_arch[] = "sparc";
196 # endif
197 #else
198 #error Add appropriate cpu_arch setting
199 #endif
200
201
202 // pid_t gettid()
203 //
204 // Returns the kernel thread id of the currently running thread. Kernel
205 // thread id is used to access /proc.
206 //
207 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
208 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
209 //
210 pid_t os::Linux::gettid() {
211 int rslt = syscall(SYS_gettid);
212 if (rslt == -1) {
213 // old kernel, no NPTL support
214 return getpid();
215 } else {
216 return (pid_t)rslt;
217 }
218 }
219
220 // Most versions of linux have a bug where the number of processors are
221 // determined by looking at the /proc file system. In a chroot environment,
222 // the system call returns 1. This causes the VM to act as if it is
223 // a single processor and elide locking (see is_MP() call).
224 static bool unsafe_chroot_detected = false;
225 static const char *unstable_chroot_error = "/proc file system not found.\n"
226 "Java may be unstable running multithreaded in a chroot "
227 "environment on Linux when /proc filesystem is not mounted.";
228
229 void os::Linux::initialize_system_info() {
230 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
231 if (processor_count() == 1) {
232 pid_t pid = os::Linux::gettid();
233 char fname[32];
234 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
235 FILE *fp = fopen(fname, "r");
236 if (fp == NULL) {
237 unsafe_chroot_detected = true;
238 } else {
239 fclose(fp);
240 }
241 }
242 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
243 assert(processor_count() > 0, "linux error");
244 }
245
246 void os::init_system_properties_values() {
247 // char arch[12];
248 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
249
250 // The next steps are taken in the product version:
251 //
252 // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
253 // This library should be located at:
254 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
255 //
256 // If "/jre/lib/" appears at the right place in the path, then we
257 // assume libjvm[_g].so is installed in a JDK and we use this path.
258 //
259 // Otherwise exit with message: "Could not create the Java virtual machine."
260 //
261 // The following extra steps are taken in the debugging version:
262 //
263 // If "/jre/lib/" does NOT appear at the right place in the path
264 // instead of exit check for $JAVA_HOME environment variable.
265 //
266 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
267 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
268 // it looks like libjvm[_g].so is installed there
269 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
270 //
271 // Otherwise exit.
272 //
273 // Important note: if the location of libjvm.so changes this
274 // code needs to be changed accordingly.
275
276 // The next few definitions allow the code to be verbatim:
277 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n))
278 #define getenv(n) ::getenv(n)
279
280 /*
281 * See ld(1):
282 * The linker uses the following search paths to locate required
283 * shared libraries:
284 * 1: ...
285 * ...
286 * 7: The default directories, normally /lib and /usr/lib.
287 */
288 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
289 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
290 #else
291 #define DEFAULT_LIBPATH "/lib:/usr/lib"
292 #endif
293
294 #define EXTENSIONS_DIR "/lib/ext"
295 #define ENDORSED_DIR "/lib/endorsed"
296 #define REG_DIR "/usr/java/packages"
297
298 {
299 /* sysclasspath, java_home, dll_dir */
300 {
301 char *home_path;
302 char *dll_path;
303 char *pslash;
304 char buf[MAXPATHLEN];
305 os::jvm_path(buf, sizeof(buf));
306
307 // Found the full path to libjvm.so.
308 // Now cut the path to <java_home>/jre if we can.
309 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
310 pslash = strrchr(buf, '/');
311 if (pslash != NULL)
312 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
313 dll_path = malloc(strlen(buf) + 1);
314 if (dll_path == NULL)
315 return;
316 strcpy(dll_path, buf);
317 Arguments::set_dll_dir(dll_path);
318
319 if (pslash != NULL) {
320 pslash = strrchr(buf, '/');
321 if (pslash != NULL) {
322 *pslash = '\0'; /* get rid of /<arch> */
323 pslash = strrchr(buf, '/');
324 if (pslash != NULL)
325 *pslash = '\0'; /* get rid of /lib */
326 }
327 }
328
329 home_path = malloc(strlen(buf) + 1);
330 if (home_path == NULL)
331 return;
332 strcpy(home_path, buf);
333 Arguments::set_java_home(home_path);
334
335 if (!set_boot_path('/', ':'))
336 return;
337 }
338
339 /*
340 * Where to look for native libraries
341 *
342 * Note: Due to a legacy implementation, most of the library path
343 * is set in the launcher. This was to accomodate linking restrictions
344 * on legacy Linux implementations (which are no longer supported).
345 * Eventually, all the library path setting will be done here.
346 *
347 * However, to prevent the proliferation of improperly built native
348 * libraries, the new path component /usr/java/packages is added here.
349 * Eventually, all the library path setting will be done here.
350 */
351 {
352 char *ld_library_path;
353
354 /*
355 * Construct the invariant part of ld_library_path. Note that the
356 * space for the colon and the trailing null are provided by the
357 * nulls included by the sizeof operator (so actually we allocate
358 * a byte more than necessary).
359 */
360 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
361 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
362 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
363
364 /*
365 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
366 * should always exist (until the legacy problem cited above is
367 * addressed).
368 */
369 char *v = getenv("LD_LIBRARY_PATH");
370 if (v != NULL) {
371 char *t = ld_library_path;
372 /* That's +1 for the colon and +1 for the trailing '\0' */
373 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
374 sprintf(ld_library_path, "%s:%s", v, t);
375 }
376 Arguments::set_library_path(ld_library_path);
377 }
378
379 /*
380 * Extensions directories.
381 *
382 * Note that the space for the colon and the trailing null are provided
383 * by the nulls included by the sizeof operator (so actually one byte more
384 * than necessary is allocated).
385 */
386 {
387 char *buf = malloc(strlen(Arguments::get_java_home()) +
388 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
389 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
390 Arguments::get_java_home());
391 Arguments::set_ext_dirs(buf);
392 }
393
394 /* Endorsed standards default directory. */
395 {
396 char * buf;
397 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
398 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
399 Arguments::set_endorsed_dirs(buf);
400 }
401 }
402
403 #undef malloc
404 #undef getenv
405 #undef EXTENSIONS_DIR
406 #undef ENDORSED_DIR
407
408 // Done
409 return;
410 }
411
412 ////////////////////////////////////////////////////////////////////////////////
413 // breakpoint support
414
415 void os::breakpoint() {
416 BREAKPOINT;
417 }
418
419 extern "C" void breakpoint() {
420 // use debugger to set breakpoint here
421 }
422
423 ////////////////////////////////////////////////////////////////////////////////
424 // signal support
425
426 debug_only(static bool signal_sets_initialized = false);
427 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
428
429 bool os::Linux::is_sig_ignored(int sig) {
430 struct sigaction oact;
431 sigaction(sig, (struct sigaction*)NULL, &oact);
432 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
433 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
434 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
435 return true;
436 else
437 return false;
438 }
439
440 void os::Linux::signal_sets_init() {
441 // Should also have an assertion stating we are still single-threaded.
442 assert(!signal_sets_initialized, "Already initialized");
443 // Fill in signals that are necessarily unblocked for all threads in
444 // the VM. Currently, we unblock the following signals:
445 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
446 // by -Xrs (=ReduceSignalUsage));
447 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
448 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
449 // the dispositions or masks wrt these signals.
450 // Programs embedding the VM that want to use the above signals for their
451 // own purposes must, at this time, use the "-Xrs" option to prevent
452 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
453 // (See bug 4345157, and other related bugs).
454 // In reality, though, unblocking these signals is really a nop, since
455 // these signals are not blocked by default.
456 sigemptyset(&unblocked_sigs);
457 sigemptyset(&allowdebug_blocked_sigs);
458 sigaddset(&unblocked_sigs, SIGILL);
459 sigaddset(&unblocked_sigs, SIGSEGV);
460 sigaddset(&unblocked_sigs, SIGBUS);
461 sigaddset(&unblocked_sigs, SIGFPE);
462 sigaddset(&unblocked_sigs, SR_signum);
463
464 if (!ReduceSignalUsage) {
465 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
466 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
467 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
468 }
469 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
470 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
471 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
472 }
473 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
474 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
475 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
476 }
477 }
478 // Fill in signals that are blocked by all but the VM thread.
479 sigemptyset(&vm_sigs);
480 if (!ReduceSignalUsage)
481 sigaddset(&vm_sigs, BREAK_SIGNAL);
482 debug_only(signal_sets_initialized = true);
483
484 }
485
486 // These are signals that are unblocked while a thread is running Java.
487 // (For some reason, they get blocked by default.)
488 sigset_t* os::Linux::unblocked_signals() {
489 assert(signal_sets_initialized, "Not initialized");
490 return &unblocked_sigs;
491 }
492
493 // These are the signals that are blocked while a (non-VM) thread is
494 // running Java. Only the VM thread handles these signals.
495 sigset_t* os::Linux::vm_signals() {
496 assert(signal_sets_initialized, "Not initialized");
497 return &vm_sigs;
498 }
499
500 // These are signals that are blocked during cond_wait to allow debugger in
501 sigset_t* os::Linux::allowdebug_blocked_signals() {
502 assert(signal_sets_initialized, "Not initialized");
503 return &allowdebug_blocked_sigs;
504 }
505
506 void os::Linux::hotspot_sigmask(Thread* thread) {
507
508 //Save caller's signal mask before setting VM signal mask
509 sigset_t caller_sigmask;
510 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
511
512 OSThread* osthread = thread->osthread();
513 osthread->set_caller_sigmask(caller_sigmask);
514
515 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
516
517 if (!ReduceSignalUsage) {
518 if (thread->is_VM_thread()) {
519 // Only the VM thread handles BREAK_SIGNAL ...
520 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
521 } else {
522 // ... all other threads block BREAK_SIGNAL
523 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
524 }
525 }
526 }
527
528 //////////////////////////////////////////////////////////////////////////////
529 // detecting pthread library
530
531 void os::Linux::libpthread_init() {
532 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
533 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
534 // generic name for earlier versions.
535 // Define macros here so we can build HotSpot on old systems.
536 # ifndef _CS_GNU_LIBC_VERSION
537 # define _CS_GNU_LIBC_VERSION 2
538 # endif
539 # ifndef _CS_GNU_LIBPTHREAD_VERSION
540 # define _CS_GNU_LIBPTHREAD_VERSION 3
541 # endif
542
543 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
544 if (n > 0) {
545 char *str = (char *)malloc(n);
546 confstr(_CS_GNU_LIBC_VERSION, str, n);
547 os::Linux::set_glibc_version(str);
548 } else {
549 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
550 static char _gnu_libc_version[32];
551 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
552 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
553 os::Linux::set_glibc_version(_gnu_libc_version);
554 }
555
556 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
557 if (n > 0) {
558 char *str = (char *)malloc(n);
559 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
560 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
561 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
562 // is the case. LinuxThreads has a hard limit on max number of threads.
563 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
564 // On the other hand, NPTL does not have such a limit, sysconf()
565 // will return -1 and errno is not changed. Check if it is really NPTL.
566 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
567 strstr(str, "NPTL") &&
568 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
569 free(str);
570 os::Linux::set_libpthread_version("linuxthreads");
571 } else {
572 os::Linux::set_libpthread_version(str);
573 }
574 } else {
575 // glibc before 2.3.2 only has LinuxThreads.
576 os::Linux::set_libpthread_version("linuxthreads");
577 }
578
579 if (strstr(libpthread_version(), "NPTL")) {
580 os::Linux::set_is_NPTL();
581 } else {
582 os::Linux::set_is_LinuxThreads();
583 }
584
585 // LinuxThreads have two flavors: floating-stack mode, which allows variable
586 // stack size; and fixed-stack mode. NPTL is always floating-stack.
587 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
588 os::Linux::set_is_floating_stack();
589 }
590 }
591
592 /////////////////////////////////////////////////////////////////////////////
593 // thread stack
594
595 // Force Linux kernel to expand current thread stack. If "bottom" is close
596 // to the stack guard, caller should block all signals.
597 //
598 // MAP_GROWSDOWN:
599 // A special mmap() flag that is used to implement thread stacks. It tells
600 // kernel that the memory region should extend downwards when needed. This
601 // allows early versions of LinuxThreads to only mmap the first few pages
602 // when creating a new thread. Linux kernel will automatically expand thread
603 // stack as needed (on page faults).
604 //
605 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
606 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
607 // region, it's hard to tell if the fault is due to a legitimate stack
608 // access or because of reading/writing non-exist memory (e.g. buffer
609 // overrun). As a rule, if the fault happens below current stack pointer,
610 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
611 // application (see Linux kernel fault.c).
612 //
613 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
614 // stack overflow detection.
615 //
616 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
617 // not use this flag. However, the stack of initial thread is not created
618 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
619 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
620 // and then attach the thread to JVM.
621 //
622 // To get around the problem and allow stack banging on Linux, we need to
623 // manually expand thread stack after receiving the SIGSEGV.
624 //
625 // There are two ways to expand thread stack to address "bottom", we used
626 // both of them in JVM before 1.5:
627 // 1. adjust stack pointer first so that it is below "bottom", and then
628 // touch "bottom"
629 // 2. mmap() the page in question
630 //
631 // Now alternate signal stack is gone, it's harder to use 2. For instance,
632 // if current sp is already near the lower end of page 101, and we need to
633 // call mmap() to map page 100, it is possible that part of the mmap() frame
634 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
635 // That will destroy the mmap() frame and cause VM to crash.
636 //
637 // The following code works by adjusting sp first, then accessing the "bottom"
638 // page to force a page fault. Linux kernel will then automatically expand the
639 // stack mapping.
640 //
641 // _expand_stack_to() assumes its frame size is less than page size, which
642 // should always be true if the function is not inlined.
643
644 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
645 #define NOINLINE
646 #else
647 #define NOINLINE __attribute__ ((noinline))
648 #endif
649
650 static void _expand_stack_to(address bottom) NOINLINE;
651
652 static void _expand_stack_to(address bottom) {
653 address sp;
654 size_t size;
655 volatile char *p;
656
657 // Adjust bottom to point to the largest address within the same page, it
658 // gives us a one-page buffer if alloca() allocates slightly more memory.
659 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
660 bottom += os::Linux::page_size() - 1;
661
662 // sp might be slightly above current stack pointer; if that's the case, we
663 // will alloca() a little more space than necessary, which is OK. Don't use
664 // os::current_stack_pointer(), as its result can be slightly below current
665 // stack pointer, causing us to not alloca enough to reach "bottom".
666 sp = (address)&sp;
667
668 if (sp > bottom) {
669 size = sp - bottom;
670 p = (volatile char *)alloca(size);
671 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
672 p[0] = '\0';
673 }
674 }
675
676 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
677 assert(t!=NULL, "just checking");
678 assert(t->osthread()->expanding_stack(), "expand should be set");
679 assert(t->stack_base() != NULL, "stack_base was not initialized");
680
681 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
682 sigset_t mask_all, old_sigset;
683 sigfillset(&mask_all);
684 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
685 _expand_stack_to(addr);
686 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
687 return true;
688 }
689 return false;
690 }
691
692 //////////////////////////////////////////////////////////////////////////////
693 // create new thread
694
695 static address highest_vm_reserved_address();
696
697 // check if it's safe to start a new thread
698 static bool _thread_safety_check(Thread* thread) {
699 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
700 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
701 // Heap is mmap'ed at lower end of memory space. Thread stacks are
702 // allocated (MAP_FIXED) from high address space. Every thread stack
703 // occupies a fixed size slot (usually 2Mbytes, but user can change
704 // it to other values if they rebuild LinuxThreads).
705 //
706 // Problem with MAP_FIXED is that mmap() can still succeed even part of
707 // the memory region has already been mmap'ed. That means if we have too
708 // many threads and/or very large heap, eventually thread stack will
709 // collide with heap.
710 //
711 // Here we try to prevent heap/stack collision by comparing current
712 // stack bottom with the highest address that has been mmap'ed by JVM
713 // plus a safety margin for memory maps created by native code.
714 //
715 // This feature can be disabled by setting ThreadSafetyMargin to 0
716 //
717 if (ThreadSafetyMargin > 0) {
718 address stack_bottom = os::current_stack_base() - os::current_stack_size();
719
720 // not safe if our stack extends below the safety margin
721 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
722 } else {
723 return true;
724 }
725 } else {
726 // Floating stack LinuxThreads or NPTL:
727 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
728 // there's not enough space left, pthread_create() will fail. If we come
729 // here, that means enough space has been reserved for stack.
730 return true;
731 }
732 }
733
734 // Thread start routine for all newly created threads
735 static void *java_start(Thread *thread) {
736 // Try to randomize the cache line index of hot stack frames.
737 // This helps when threads of the same stack traces evict each other's
738 // cache lines. The threads can be either from the same JVM instance, or
739 // from different JVM instances. The benefit is especially true for
740 // processors with hyperthreading technology.
741 static int counter = 0;
742 int pid = os::current_process_id();
743 alloca(((pid ^ counter++) & 7) * 128);
744
745 ThreadLocalStorage::set_thread(thread);
746
747 OSThread* osthread = thread->osthread();
748 Monitor* sync = osthread->startThread_lock();
749
750 // non floating stack LinuxThreads needs extra check, see above
751 if (!_thread_safety_check(thread)) {
752 // notify parent thread
753 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
754 osthread->set_state(ZOMBIE);
755 sync->notify_all();
756 return NULL;
757 }
758
759 // thread_id is kernel thread id (similar to Solaris LWP id)
760 osthread->set_thread_id(os::Linux::gettid());
761
762 if (UseNUMA) {
763 int lgrp_id = os::numa_get_group_id();
764 if (lgrp_id != -1) {
765 thread->set_lgrp_id(lgrp_id);
766 }
767 }
768 // initialize signal mask for this thread
769 os::Linux::hotspot_sigmask(thread);
770
771 // initialize floating point control register
772 os::Linux::init_thread_fpu_state();
773
774 // handshaking with parent thread
775 {
776 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
777
778 // notify parent thread
779 osthread->set_state(INITIALIZED);
780 sync->notify_all();
781
782 // wait until os::start_thread()
783 while (osthread->get_state() == INITIALIZED) {
784 sync->wait(Mutex::_no_safepoint_check_flag);
785 }
786 }
787
788 // call one more level start routine
789 thread->run();
790
791 return 0;
792 }
793
794 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
795 assert(thread->osthread() == NULL, "caller responsible");
796
797 // Allocate the OSThread object
798 OSThread* osthread = new OSThread(NULL, NULL);
799 if (osthread == NULL) {
800 return false;
801 }
802
803 // set the correct thread state
804 osthread->set_thread_type(thr_type);
805
806 // Initial state is ALLOCATED but not INITIALIZED
807 osthread->set_state(ALLOCATED);
808
809 thread->set_osthread(osthread);
810
811 // init thread attributes
812 pthread_attr_t attr;
813 pthread_attr_init(&attr);
814 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
815
816 // stack size
817 if (os::Linux::supports_variable_stack_size()) {
818 // calculate stack size if it's not specified by caller
819 if (stack_size == 0) {
820 stack_size = os::Linux::default_stack_size(thr_type);
821
822 switch (thr_type) {
823 case os::java_thread:
824 // Java threads use ThreadStackSize which default value can be changed with the flag -Xss
825 if (JavaThread::stack_size_at_create() > 0) stack_size = JavaThread::stack_size_at_create();
826 break;
827 case os::compiler_thread:
828 if (CompilerThreadStackSize > 0) {
829 stack_size = (size_t)(CompilerThreadStackSize * K);
830 break;
831 } // else fall through:
832 // use VMThreadStackSize if CompilerThreadStackSize is not defined
833 case os::vm_thread:
834 case os::pgc_thread:
835 case os::cgc_thread:
836 case os::watcher_thread:
837 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
838 break;
839 }
840 }
841
842 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
843 pthread_attr_setstacksize(&attr, stack_size);
844 } else {
845 // let pthread_create() pick the default value.
846 }
847
848 // glibc guard page
849 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
850
851 ThreadState state;
852
853 {
854 // Serialize thread creation if we are running with fixed stack LinuxThreads
855 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
856 if (lock) {
857 os::Linux::createThread_lock()->lock_without_safepoint_check();
858 }
859
860 pthread_t tid;
861 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
862
863 pthread_attr_destroy(&attr);
864
865 if (ret != 0) {
866 if (PrintMiscellaneous && (Verbose || WizardMode)) {
867 perror("pthread_create()");
868 }
869 // Need to clean up stuff we've allocated so far
870 thread->set_osthread(NULL);
871 delete osthread;
872 if (lock) os::Linux::createThread_lock()->unlock();
873 return false;
874 }
875
876 // Store pthread info into the OSThread
877 osthread->set_pthread_id(tid);
878
879 // Wait until child thread is either initialized or aborted
880 {
881 Monitor* sync_with_child = osthread->startThread_lock();
882 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
883 while ((state = osthread->get_state()) == ALLOCATED) {
884 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
885 }
886 }
887
888 if (lock) {
889 os::Linux::createThread_lock()->unlock();
890 }
891 }
892
893 // Aborted due to thread limit being reached
894 if (state == ZOMBIE) {
895 thread->set_osthread(NULL);
896 delete osthread;
897 return false;
898 }
899
900 // The thread is returned suspended (in state INITIALIZED),
901 // and is started higher up in the call chain
902 assert(state == INITIALIZED, "race condition");
903 return true;
904 }
905
906 /////////////////////////////////////////////////////////////////////////////
907 // attach existing thread
908
909 // bootstrap the main thread
910 bool os::create_main_thread(JavaThread* thread) {
911 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
912 return create_attached_thread(thread);
913 }
914
915 bool os::create_attached_thread(JavaThread* thread) {
916 #ifdef ASSERT
917 thread->verify_not_published();
918 #endif
919
920 // Allocate the OSThread object
921 OSThread* osthread = new OSThread(NULL, NULL);
922
923 if (osthread == NULL) {
924 return false;
925 }
926
927 // Store pthread info into the OSThread
928 osthread->set_thread_id(os::Linux::gettid());
929 osthread->set_pthread_id(::pthread_self());
930
931 // initialize floating point control register
932 os::Linux::init_thread_fpu_state();
933
934 // Initial thread state is RUNNABLE
935 osthread->set_state(RUNNABLE);
936
937 thread->set_osthread(osthread);
938
939 if (UseNUMA) {
940 int lgrp_id = os::numa_get_group_id();
941 if (lgrp_id != -1) {
942 thread->set_lgrp_id(lgrp_id);
943 }
944 }
945
946 if (os::Linux::is_initial_thread()) {
947 // If current thread is initial thread, its stack is mapped on demand,
948 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
949 // the entire stack region to avoid SEGV in stack banging.
950 // It is also useful to get around the heap-stack-gap problem on SuSE
951 // kernel (see 4821821 for details). We first expand stack to the top
952 // of yellow zone, then enable stack yellow zone (order is significant,
953 // enabling yellow zone first will crash JVM on SuSE Linux), so there
954 // is no gap between the last two virtual memory regions.
955
956 JavaThread *jt = (JavaThread *)thread;
957 address addr = jt->stack_yellow_zone_base();
958 assert(addr != NULL, "initialization problem?");
959 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
960
961 osthread->set_expanding_stack();
962 os::Linux::manually_expand_stack(jt, addr);
963 osthread->clear_expanding_stack();
964 }
965
966 // initialize signal mask for this thread
967 // and save the caller's signal mask
968 os::Linux::hotspot_sigmask(thread);
969
970 return true;
971 }
972
973 void os::pd_start_thread(Thread* thread) {
974 OSThread * osthread = thread->osthread();
975 assert(osthread->get_state() != INITIALIZED, "just checking");
976 Monitor* sync_with_child = osthread->startThread_lock();
977 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
978 sync_with_child->notify();
979 }
980
981 // Free Linux resources related to the OSThread
982 void os::free_thread(OSThread* osthread) {
983 assert(osthread != NULL, "osthread not set");
984
985 if (Thread::current()->osthread() == osthread) {
986 // Restore caller's signal mask
987 sigset_t sigmask = osthread->caller_sigmask();
988 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
989 }
990
991 delete osthread;
992 }
993
994 //////////////////////////////////////////////////////////////////////////////
995 // thread local storage
996
997 int os::allocate_thread_local_storage() {
998 pthread_key_t key;
999 int rslt = pthread_key_create(&key, NULL);
1000 assert(rslt == 0, "cannot allocate thread local storage");
1001 return (int)key;
1002 }
1003
1004 // Note: This is currently not used by VM, as we don't destroy TLS key
1005 // on VM exit.
1006 void os::free_thread_local_storage(int index) {
1007 int rslt = pthread_key_delete((pthread_key_t)index);
1008 assert(rslt == 0, "invalid index");
1009 }
1010
1011 void os::thread_local_storage_at_put(int index, void* value) {
1012 int rslt = pthread_setspecific((pthread_key_t)index, value);
1013 assert(rslt == 0, "pthread_setspecific failed");
1014 }
1015
1016 extern "C" Thread* get_thread() {
1017 return ThreadLocalStorage::thread();
1018 }
1019
1020 //////////////////////////////////////////////////////////////////////////////
1021 // initial thread
1022
1023 // Check if current thread is the initial thread, similar to Solaris thr_main.
1024 bool os::Linux::is_initial_thread(void) {
1025 char dummy;
1026 // If called before init complete, thread stack bottom will be null.
1027 // Can be called if fatal error occurs before initialization.
1028 if (initial_thread_stack_bottom() == NULL) return false;
1029 assert(initial_thread_stack_bottom() != NULL &&
1030 initial_thread_stack_size() != 0,
1031 "os::init did not locate initial thread's stack region");
1032 if ((address)&dummy >= initial_thread_stack_bottom() &&
1033 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1034 return true;
1035 else return false;
1036 }
1037
1038 // Find the virtual memory area that contains addr
1039 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1040 FILE *fp = fopen("/proc/self/maps", "r");
1041 if (fp) {
1042 address low, high;
1043 while (!feof(fp)) {
1044 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1045 if (low <= addr && addr < high) {
1046 if (vma_low) *vma_low = low;
1047 if (vma_high) *vma_high = high;
1048 fclose (fp);
1049 return true;
1050 }
1051 }
1052 for (;;) {
1053 int ch = fgetc(fp);
1054 if (ch == EOF || ch == (int)'\n') break;
1055 }
1056 }
1057 fclose(fp);
1058 }
1059 return false;
1060 }
1061
1062 // Locate initial thread stack. This special handling of initial thread stack
1063 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1064 // bogus value for initial thread.
1065 void os::Linux::capture_initial_stack(size_t max_size) {
1066 // stack size is the easy part, get it from RLIMIT_STACK
1067 size_t stack_size;
1068 struct rlimit rlim;
1069 getrlimit(RLIMIT_STACK, &rlim);
1070 stack_size = rlim.rlim_cur;
1071
1072 // 6308388: a bug in ld.so will relocate its own .data section to the
1073 // lower end of primordial stack; reduce ulimit -s value a little bit
1074 // so we won't install guard page on ld.so's data section.
1075 stack_size -= 2 * page_size();
1076
1077 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1078 // 7.1, in both cases we will get 2G in return value.
1079 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1080 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1081 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1082 // in case other parts in glibc still assumes 2M max stack size.
1083 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1084 #ifndef IA64
1085 if (stack_size > 2 * K * K) stack_size = 2 * K * K;
1086 #else
1087 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1088 if (stack_size > 4 * K * K) stack_size = 4 * K * K;
1089 #endif
1090
1091 // Try to figure out where the stack base (top) is. This is harder.
1092 //
1093 // When an application is started, glibc saves the initial stack pointer in
1094 // a global variable "__libc_stack_end", which is then used by system
1095 // libraries. __libc_stack_end should be pretty close to stack top. The
1096 // variable is available since the very early days. However, because it is
1097 // a private interface, it could disappear in the future.
1098 //
1099 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1100 // to __libc_stack_end, it is very close to stack top, but isn't the real
1101 // stack top. Note that /proc may not exist if VM is running as a chroot
1102 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1103 // /proc/<pid>/stat could change in the future (though unlikely).
1104 //
1105 // We try __libc_stack_end first. If that doesn't work, look for
1106 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1107 // as a hint, which should work well in most cases.
1108
1109 uintptr_t stack_start;
1110
1111 // try __libc_stack_end first
1112 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1113 if (p && *p) {
1114 stack_start = *p;
1115 } else {
1116 // see if we can get the start_stack field from /proc/self/stat
1117 FILE *fp;
1118 int pid;
1119 char state;
1120 int ppid;
1121 int pgrp;
1122 int session;
1123 int nr;
1124 int tpgrp;
1125 unsigned long flags;
1126 unsigned long minflt;
1127 unsigned long cminflt;
1128 unsigned long majflt;
1129 unsigned long cmajflt;
1130 unsigned long utime;
1131 unsigned long stime;
1132 long cutime;
1133 long cstime;
1134 long prio;
1135 long nice;
1136 long junk;
1137 long it_real;
1138 uintptr_t start;
1139 uintptr_t vsize;
1140 uintptr_t rss;
1141 unsigned long rsslim;
1142 uintptr_t scodes;
1143 uintptr_t ecode;
1144 int i;
1145
1146 // Figure what the primordial thread stack base is. Code is inspired
1147 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1148 // followed by command name surrounded by parentheses, state, etc.
1149 char stat[2048];
1150 int statlen;
1151
1152 fp = fopen("/proc/self/stat", "r");
1153 if (fp) {
1154 statlen = fread(stat, 1, 2047, fp);
1155 stat[statlen] = '\0';
1156 fclose(fp);
1157
1158 // Skip pid and the command string. Note that we could be dealing with
1159 // weird command names, e.g. user could decide to rename java launcher
1160 // to "java 1.4.2 :)", then the stat file would look like
1161 // 1234 (java 1.4.2 :)) R ... ...
1162 // We don't really need to know the command string, just find the last
1163 // occurrence of ")" and then start parsing from there. See bug 4726580.
1164 char * s = strrchr(stat, ')');
1165
1166 i = 0;
1167 if (s) {
1168 // Skip blank chars
1169 do s++; while (isspace(*s));
1170
1171 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1172 /* 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 */
1173 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld "
1174 UINTX_FORMAT UINTX_FORMAT UINTX_FORMAT
1175 " %lu "
1176 UINTX_FORMAT UINTX_FORMAT UINTX_FORMAT,
1177 &state, /* 3 %c */
1178 &ppid, /* 4 %d */
1179 &pgrp, /* 5 %d */
1180 &session, /* 6 %d */
1181 &nr, /* 7 %d */
1182 &tpgrp, /* 8 %d */
1183 &flags, /* 9 %lu */
1184 &minflt, /* 10 %lu */
1185 &cminflt, /* 11 %lu */
1186 &majflt, /* 12 %lu */
1187 &cmajflt, /* 13 %lu */
1188 &utime, /* 14 %lu */
1189 &stime, /* 15 %lu */
1190 &cutime, /* 16 %ld */
1191 &cstime, /* 17 %ld */
1192 &prio, /* 18 %ld */
1193 &nice, /* 19 %ld */
1194 &junk, /* 20 %ld */
1195 &it_real, /* 21 %ld */
1196 &start, /* 22 UINTX_FORMAT */
1197 &vsize, /* 23 UINTX_FORMAT */
1198 &rss, /* 24 UINTX_FORMAT */
1199 &rsslim, /* 25 %lu */
1200 &scodes, /* 26 UINTX_FORMAT */
1201 &ecode, /* 27 UINTX_FORMAT */
1202 &stack_start); /* 28 UINTX_FORMAT */
1203 }
1204
1205 if (i != 28 - 2) {
1206 assert(false, "Bad conversion from /proc/self/stat");
1207 // product mode - assume we are the initial thread, good luck in the
1208 // embedded case.
1209 warning("Can't detect initial thread stack location - bad conversion");
1210 stack_start = (uintptr_t) &rlim;
1211 }
1212 } else {
1213 // For some reason we can't open /proc/self/stat (for example, running on
1214 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1215 // most cases, so don't abort:
1216 warning("Can't detect initial thread stack location - no /proc/self/stat");
1217 stack_start = (uintptr_t) &rlim;
1218 }
1219 }
1220
1221 // Now we have a pointer (stack_start) very close to the stack top, the
1222 // next thing to do is to figure out the exact location of stack top. We
1223 // can find out the virtual memory area that contains stack_start by
1224 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1225 // and its upper limit is the real stack top. (again, this would fail if
1226 // running inside chroot, because /proc may not exist.)
1227
1228 uintptr_t stack_top;
1229 address low, high;
1230 if (find_vma((address)stack_start, &low, &high)) {
1231 // success, "high" is the true stack top. (ignore "low", because initial
1232 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1233 stack_top = (uintptr_t)high;
1234 } else {
1235 // failed, likely because /proc/self/maps does not exist
1236 warning("Can't detect initial thread stack location - find_vma failed");
1237 // best effort: stack_start is normally within a few pages below the real
1238 // stack top, use it as stack top, and reduce stack size so we won't put
1239 // guard page outside stack.
1240 stack_top = stack_start;
1241 stack_size -= 16 * page_size();
1242 }
1243
1244 // stack_top could be partially down the page so align it
1245 stack_top = align_size_up(stack_top, page_size());
1246
1247 if (max_size && stack_size > max_size) {
1248 _initial_thread_stack_size = max_size;
1249 } else {
1250 _initial_thread_stack_size = stack_size;
1251 }
1252
1253 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1254 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1255 }
1256
1257 ////////////////////////////////////////////////////////////////////////////////
1258 // time support
1259
1260 // Time since start-up in seconds to a fine granularity.
1261 // Used by VMSelfDestructTimer and the MemProfiler.
1262 double os::elapsedTime() {
1263
1264 return (double)(os::elapsed_counter()) * 0.000001;
1265 }
1266
1267 jlong os::elapsed_counter() {
1268 timeval time;
1269 int status = gettimeofday(&time, NULL);
1270 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1271 }
1272
1273 jlong os::elapsed_frequency() {
1274 return (1000 * 1000);
1275 }
1276
1277 // For now, we say that linux does not support vtime. I have no idea
1278 // whether it can actually be made to (DLD, 9/13/05).
1279
1280 bool os::supports_vtime() { return false; }
1281 bool os::enable_vtime() { return false; }
1282 bool os::vtime_enabled() { return false; }
1283 double os::elapsedVTime() {
1284 // better than nothing, but not much
1285 return elapsedTime();
1286 }
1287
1288 jlong os::javaTimeMillis() {
1289 timeval time;
1290 int status = gettimeofday(&time, NULL);
1291 assert(status != -1, "linux error");
1292 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1293 }
1294
1295 #ifndef CLOCK_MONOTONIC
1296 #define CLOCK_MONOTONIC (1)
1297 #endif
1298
1299 void os::Linux::clock_init() {
1300 // we do dlopen's in this particular order due to bug in linux
1301 // dynamical loader (see 6348968) leading to crash on exit
1302 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1303 if (handle == NULL) {
1304 handle = dlopen("librt.so", RTLD_LAZY);
1305 }
1306
1307 if (handle) {
1308 int (*clock_getres_func)(clockid_t, struct timespec*) =
1309 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1310 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1311 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1312 if (clock_getres_func && clock_gettime_func) {
1313 // See if monotonic clock is supported by the kernel. Note that some
1314 // early implementations simply return kernel jiffies (updated every
1315 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1316 // for nano time (though the monotonic property is still nice to have).
1317 // It's fixed in newer kernels, however clock_getres() still returns
1318 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1319 // resolution for now. Hopefully as people move to new kernels, this
1320 // won't be a problem.
1321 struct timespec res;
1322 struct timespec tp;
1323 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1324 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1325 // yes, monotonic clock is supported
1326 _clock_gettime = clock_gettime_func;
1327 } else {
1328 // close librt if there is no monotonic clock
1329 dlclose(handle);
1330 }
1331 }
1332 }
1333 }
1334
1335 #ifndef SYS_clock_getres
1336
1337 #if defined(IA32) || defined(AMD64)
1338 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1339 #else
1340 #error Value of SYS_clock_getres not known on this platform
1341 #endif
1342
1343 #endif
1344
1345 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1346
1347 void os::Linux::fast_thread_clock_init() {
1348 if (!UseLinuxPosixThreadCPUClocks) {
1349 return;
1350 }
1351 clockid_t clockid;
1352 struct timespec tp;
1353 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1354 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1355
1356 // Switch to using fast clocks for thread cpu time if
1357 // the sys_clock_getres() returns 0 error code.
1358 // Note, that some kernels may support the current thread
1359 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1360 // returned by the pthread_getcpuclockid().
1361 // If the fast Posix clocks are supported then the sys_clock_getres()
1362 // must return at least tp.tv_sec == 0 which means a resolution
1363 // better than 1 sec. This is extra check for reliability.
1364
1365 if(pthread_getcpuclockid_func &&
1366 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1367 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1368
1369 _supports_fast_thread_cpu_time = true;
1370 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1371 }
1372 }
1373
1374 jlong os::javaTimeNanos() {
1375 if (Linux::supports_monotonic_clock()) {
1376 struct timespec tp;
1377 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1378 assert(status == 0, "gettime error");
1379 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1380 return result;
1381 } else {
1382 timeval time;
1383 int status = gettimeofday(&time, NULL);
1384 assert(status != -1, "linux error");
1385 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1386 return 1000 * usecs;
1387 }
1388 }
1389
1390 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1391 if (Linux::supports_monotonic_clock()) {
1392 info_ptr->max_value = ALL_64_BITS;
1393
1394 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1395 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1396 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1397 } else {
1398 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1399 info_ptr->max_value = ALL_64_BITS;
1400
1401 // gettimeofday is a real time clock so it skips
1402 info_ptr->may_skip_backward = true;
1403 info_ptr->may_skip_forward = true;
1404 }
1405
1406 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1407 }
1408
1409 // Return the real, user, and system times in seconds from an
1410 // arbitrary fixed point in the past.
1411 bool os::getTimesSecs(double* process_real_time,
1412 double* process_user_time,
1413 double* process_system_time) {
1414 struct tms ticks;
1415 clock_t real_ticks = times(&ticks);
1416
1417 if (real_ticks == (clock_t) (-1)) {
1418 return false;
1419 } else {
1420 double ticks_per_second = (double) clock_tics_per_sec;
1421 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1422 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1423 *process_real_time = ((double) real_ticks) / ticks_per_second;
1424
1425 return true;
1426 }
1427 }
1428
1429
1430 char * os::local_time_string(char *buf, size_t buflen) {
1431 struct tm t;
1432 time_t long_time;
1433 time(&long_time);
1434 localtime_r(&long_time, &t);
1435 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1436 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1437 t.tm_hour, t.tm_min, t.tm_sec);
1438 return buf;
1439 }
1440
1441 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1442 return localtime_r(clock, res);
1443 }
1444
1445 ////////////////////////////////////////////////////////////////////////////////
1446 // runtime exit support
1447
1448 // Note: os::shutdown() might be called very early during initialization, or
1449 // called from signal handler. Before adding something to os::shutdown(), make
1450 // sure it is async-safe and can handle partially initialized VM.
1451 void os::shutdown() {
1452
1453 // allow PerfMemory to attempt cleanup of any persistent resources
1454 perfMemory_exit();
1455
1456 // needs to remove object in file system
1457 AttachListener::abort();
1458
1459 // flush buffered output, finish log files
1460 ostream_abort();
1461
1462 // Check for abort hook
1463 abort_hook_t abort_hook = Arguments::abort_hook();
1464 if (abort_hook != NULL) {
1465 abort_hook();
1466 }
1467
1468 }
1469
1470 // Note: os::abort() might be called very early during initialization, or
1471 // called from signal handler. Before adding something to os::abort(), make
1472 // sure it is async-safe and can handle partially initialized VM.
1473 void os::abort(bool dump_core) {
1474 os::shutdown();
1475 if (dump_core) {
1476 #ifndef PRODUCT
1477 fdStream out(defaultStream::output_fd());
1478 out.print_raw("Current thread is ");
1479 char buf[16];
1480 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1481 out.print_raw_cr(buf);
1482 out.print_raw_cr("Dumping core ...");
1483 #endif
1484 ::abort(); // dump core
1485 }
1486
1487 ::exit(1);
1488 }
1489
1490 // Die immediately, no exit hook, no abort hook, no cleanup.
1491 void os::die() {
1492 // _exit() on LinuxThreads only kills current thread
1493 ::abort();
1494 }
1495
1496 // unused on linux for now.
1497 void os::set_error_file(const char *logfile) {}
1498
1499 intx os::current_thread_id() { return (intx)pthread_self(); }
1500 int os::current_process_id() {
1501
1502 // Under the old linux thread library, linux gives each thread
1503 // its own process id. Because of this each thread will return
1504 // a different pid if this method were to return the result
1505 // of getpid(2). Linux provides no api that returns the pid
1506 // of the launcher thread for the vm. This implementation
1507 // returns a unique pid, the pid of the launcher thread
1508 // that starts the vm 'process'.
1509
1510 // Under the NPTL, getpid() returns the same pid as the
1511 // launcher thread rather than a unique pid per thread.
1512 // Use gettid() if you want the old pre NPTL behaviour.
1513
1514 // if you are looking for the result of a call to getpid() that
1515 // returns a unique pid for the calling thread, then look at the
1516 // OSThread::thread_id() method in osThread_linux.hpp file
1517
1518 return (int)(_initial_pid ? _initial_pid : getpid());
1519 }
1520
1521 // DLL functions
1522
1523 const char* os::dll_file_extension() { return ".so"; }
1524
1525 const char* os::get_temp_directory() { return "/tmp/"; }
1526
1527 static bool file_exists(const char* filename) {
1528 struct stat statbuf;
1529 if (filename == NULL || strlen(filename) == 0) {
1530 return false;
1531 }
1532 return os::stat(filename, &statbuf) == 0;
1533 }
1534
1535 void os::dll_build_name(char* buffer, size_t buflen,
1536 const char* pname, const char* fname) {
1537 // Copied from libhpi
1538 const size_t pnamelen = pname ? strlen(pname) : 0;
1539
1540 // Quietly truncate on buffer overflow. Should be an error.
1541 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1542 *buffer = '\0';
1543 return;
1544 }
1545
1546 if (pnamelen == 0) {
1547 snprintf(buffer, buflen, "lib%s.so", fname);
1548 } else if (strchr(pname, *os::path_separator()) != NULL) {
1549 int n;
1550 char** pelements = split_path(pname, &n);
1551 for (int i = 0 ; i < n ; i++) {
1552 // Really shouldn't be NULL, but check can't hurt
1553 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1554 continue; // skip the empty path values
1555 }
1556 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1557 if (file_exists(buffer)) {
1558 break;
1559 }
1560 }
1561 // release the storage
1562 for (int i = 0 ; i < n ; i++) {
1563 if (pelements[i] != NULL) {
1564 FREE_C_HEAP_ARRAY(char, pelements[i]);
1565 }
1566 }
1567 if (pelements != NULL) {
1568 FREE_C_HEAP_ARRAY(char*, pelements);
1569 }
1570 } else {
1571 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1572 }
1573 }
1574
1575 const char* os::get_current_directory(char *buf, int buflen) {
1576 return getcwd(buf, buflen);
1577 }
1578
1579 // check if addr is inside libjvm[_g].so
1580 bool os::address_is_in_vm(address addr) {
1581 static address libjvm_base_addr;
1582 Dl_info dlinfo;
1583
1584 if (libjvm_base_addr == NULL) {
1585 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
1586 libjvm_base_addr = (address)dlinfo.dli_fbase;
1587 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1588 }
1589
1590 if (dladdr((void *)addr, &dlinfo)) {
1591 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1592 }
1593
1594 return false;
1595 }
1596
1597 bool os::dll_address_to_function_name(address addr, char *buf,
1598 int buflen, int *offset) {
1599 Dl_info dlinfo;
1600
1601 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
1602 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1603 if (offset) *offset = addr - (address)dlinfo.dli_saddr;
1604 return true;
1605 } else {
1606 if (buf) buf[0] = '\0';
1607 if (offset) *offset = -1;
1608 return false;
1609 }
1610 }
1611
1612 struct _address_to_library_name {
1613 address addr; // input : memory address
1614 size_t buflen; // size of fname
1615 char* fname; // output: library name
1616 address base; // library base addr
1617 };
1618
1619 static int address_to_library_name_callback(struct dl_phdr_info *info,
1620 size_t size, void *data) {
1621 int i;
1622 bool found = false;
1623 address libbase = NULL;
1624 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1625
1626 // iterate through all loadable segments
1627 for (i = 0; i < info->dlpi_phnum; i++) {
1628 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1629 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1630 // base address of a library is the lowest address of its loaded
1631 // segments.
1632 if (libbase == NULL || libbase > segbase) {
1633 libbase = segbase;
1634 }
1635 // see if 'addr' is within current segment
1636 if (segbase <= d->addr &&
1637 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1638 found = true;
1639 }
1640 }
1641 }
1642
1643 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1644 // so dll_address_to_library_name() can fall through to use dladdr() which
1645 // can figure out executable name from argv[0].
1646 if (found && info->dlpi_name && info->dlpi_name[0]) {
1647 d->base = libbase;
1648 if (d->fname) {
1649 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1650 }
1651 return 1;
1652 }
1653 return 0;
1654 }
1655
1656 bool os::dll_address_to_library_name(address addr, char* buf,
1657 int buflen, int* offset) {
1658 Dl_info dlinfo;
1659 struct _address_to_library_name data;
1660
1661 // There is a bug in old glibc dladdr() implementation that it could resolve
1662 // to wrong library name if the .so file has a base address != NULL. Here
1663 // we iterate through the program headers of all loaded libraries to find
1664 // out which library 'addr' really belongs to. This workaround can be
1665 // removed once the minimum requirement for glibc is moved to 2.3.x.
1666 data.addr = addr;
1667 data.fname = buf;
1668 data.buflen = buflen;
1669 data.base = NULL;
1670 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1671
1672 if (rslt) {
1673 // buf already contains library name
1674 if (offset) *offset = addr - data.base;
1675 return true;
1676 } else if (dladdr((void*)addr, &dlinfo)){
1677 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1678 if (offset) *offset = addr - (address)dlinfo.dli_fbase;
1679 return true;
1680 } else {
1681 if (buf) buf[0] = '\0';
1682 if (offset) *offset = -1;
1683 return false;
1684 }
1685 }
1686
1687 // Loads .dll/.so and
1688 // in case of error it checks if .dll/.so was built for the
1689 // same architecture as Hotspot is running on
1690
1691 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1692 {
1693 void * result= ::dlopen(filename, RTLD_LAZY);
1694 if (result != NULL) {
1695 // Successful loading
1696 return result;
1697 }
1698
1699 Elf32_Ehdr elf_head;
1700
1701 // Read system error message into ebuf
1702 // It may or may not be overwritten below
1703 ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1704 ebuf[ebuflen-1]='\0';
1705 int diag_msg_max_length=ebuflen-strlen(ebuf);
1706 char* diag_msg_buf=ebuf+strlen(ebuf);
1707
1708 if (diag_msg_max_length==0) {
1709 // No more space in ebuf for additional diagnostics message
1710 return NULL;
1711 }
1712
1713
1714 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1715
1716 if (file_descriptor < 0) {
1717 // Can't open library, report dlerror() message
1718 return NULL;
1719 }
1720
1721 bool failed_to_read_elf_head=
1722 (sizeof(elf_head)!=
1723 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1724
1725 ::close(file_descriptor);
1726 if (failed_to_read_elf_head) {
1727 // file i/o error - report dlerror() msg
1728 return NULL;
1729 }
1730
1731 typedef struct {
1732 Elf32_Half code; // Actual value as defined in elf.h
1733 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1734 char elf_class; // 32 or 64 bit
1735 char endianess; // MSB or LSB
1736 char* name; // String representation
1737 } arch_t;
1738
1739 #ifndef EM_486
1740 #define EM_486 6 /* Intel 80486 */
1741 #endif
1742
1743 static const arch_t arch_array[]={
1744 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1745 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1746 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1747 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1748 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1749 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1750 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1751 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1752 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1753 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1754 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1755 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1756 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1757 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1758 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1759 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1760 };
1761
1762 #if (defined IA32)
1763 static Elf32_Half running_arch_code=EM_386;
1764 #elif (defined AMD64)
1765 static Elf32_Half running_arch_code=EM_X86_64;
1766 #elif (defined IA64)
1767 static Elf32_Half running_arch_code=EM_IA_64;
1768 #elif (defined __sparc) && (defined _LP64)
1769 static Elf32_Half running_arch_code=EM_SPARCV9;
1770 #elif (defined __sparc) && (!defined _LP64)
1771 static Elf32_Half running_arch_code=EM_SPARC;
1772 #elif (defined __powerpc64__)
1773 static Elf32_Half running_arch_code=EM_PPC64;
1774 #elif (defined __powerpc__)
1775 static Elf32_Half running_arch_code=EM_PPC;
1776 #elif (defined ARM)
1777 static Elf32_Half running_arch_code=EM_ARM;
1778 #elif (defined S390)
1779 static Elf32_Half running_arch_code=EM_S390;
1780 #elif (defined ALPHA)
1781 static Elf32_Half running_arch_code=EM_ALPHA;
1782 #elif (defined MIPSEL)
1783 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1784 #elif (defined PARISC)
1785 static Elf32_Half running_arch_code=EM_PARISC;
1786 #elif (defined MIPS)
1787 static Elf32_Half running_arch_code=EM_MIPS;
1788 #elif (defined M68K)
1789 static Elf32_Half running_arch_code=EM_68K;
1790 #else
1791 #error Method os::dll_load requires that one of following is defined:\
1792 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1793 #endif
1794
1795 // Identify compatability class for VM's architecture and library's architecture
1796 // Obtain string descriptions for architectures
1797
1798 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1799 int running_arch_index=-1;
1800
1801 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1802 if (running_arch_code == arch_array[i].code) {
1803 running_arch_index = i;
1804 }
1805 if (lib_arch.code == arch_array[i].code) {
1806 lib_arch.compat_class = arch_array[i].compat_class;
1807 lib_arch.name = arch_array[i].name;
1808 }
1809 }
1810
1811 assert(running_arch_index != -1,
1812 "Didn't find running architecture code (running_arch_code) in arch_array");
1813 if (running_arch_index == -1) {
1814 // Even though running architecture detection failed
1815 // we may still continue with reporting dlerror() message
1816 return NULL;
1817 }
1818
1819 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1820 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1821 return NULL;
1822 }
1823
1824 #ifndef S390
1825 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1826 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1827 return NULL;
1828 }
1829 #endif // !S390
1830
1831 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1832 if ( lib_arch.name!=NULL ) {
1833 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1834 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1835 lib_arch.name, arch_array[running_arch_index].name);
1836 } else {
1837 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1838 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1839 lib_arch.code,
1840 arch_array[running_arch_index].name);
1841 }
1842 }
1843
1844 return NULL;
1845 }
1846
1847 /*
1848 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
1849 * chances are you might want to run the generated bits against glibc-2.0
1850 * libdl.so, so always use locking for any version of glibc.
1851 */
1852 void* os::dll_lookup(void* handle, const char* name) {
1853 pthread_mutex_lock(&dl_mutex);
1854 void* res = dlsym(handle, name);
1855 pthread_mutex_unlock(&dl_mutex);
1856 return res;
1857 }
1858
1859
1860 bool _print_ascii_file(const char* filename, outputStream* st) {
1861 int fd = open(filename, O_RDONLY);
1862 if (fd == -1) {
1863 return false;
1864 }
1865
1866 char buf[32];
1867 int bytes;
1868 while ((bytes = read(fd, buf, sizeof(buf))) > 0) {
1869 st->print_raw(buf, bytes);
1870 }
1871
1872 close(fd);
1873
1874 return true;
1875 }
1876
1877 void os::print_dll_info(outputStream *st) {
1878 st->print_cr("Dynamic libraries:");
1879
1880 char fname[32];
1881 pid_t pid = os::Linux::gettid();
1882
1883 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
1884
1885 if (!_print_ascii_file(fname, st)) {
1886 st->print("Can not get library information for pid = %d\n", pid);
1887 }
1888 }
1889
1890
1891 void os::print_os_info(outputStream* st) {
1892 st->print("OS:");
1893
1894 // Try to identify popular distros.
1895 // Most Linux distributions have /etc/XXX-release file, which contains
1896 // the OS version string. Some have more than one /etc/XXX-release file
1897 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
1898 // so the order is important.
1899 if (!_print_ascii_file("/etc/mandrake-release", st) &&
1900 !_print_ascii_file("/etc/sun-release", st) &&
1901 !_print_ascii_file("/etc/redhat-release", st) &&
1902 !_print_ascii_file("/etc/SuSE-release", st) &&
1903 !_print_ascii_file("/etc/turbolinux-release", st) &&
1904 !_print_ascii_file("/etc/gentoo-release", st) &&
1905 !_print_ascii_file("/etc/debian_version", st)) {
1906 st->print("Linux");
1907 }
1908 st->cr();
1909
1910 // kernel
1911 st->print("uname:");
1912 struct utsname name;
1913 uname(&name);
1914 st->print(name.sysname); st->print(" ");
1915 st->print(name.release); st->print(" ");
1916 st->print(name.version); st->print(" ");
1917 st->print(name.machine);
1918 st->cr();
1919
1920 // Print warning if unsafe chroot environment detected
1921 if (unsafe_chroot_detected) {
1922 st->print("WARNING!! ");
1923 st->print_cr(unstable_chroot_error);
1924 }
1925
1926 // libc, pthread
1927 st->print("libc:");
1928 st->print(os::Linux::glibc_version()); st->print(" ");
1929 st->print(os::Linux::libpthread_version()); st->print(" ");
1930 if (os::Linux::is_LinuxThreads()) {
1931 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
1932 }
1933 st->cr();
1934
1935 // rlimit
1936 st->print("rlimit:");
1937 struct rlimit rlim;
1938
1939 st->print(" STACK ");
1940 getrlimit(RLIMIT_STACK, &rlim);
1941 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1942 else st->print("%uk", rlim.rlim_cur >> 10);
1943
1944 st->print(", CORE ");
1945 getrlimit(RLIMIT_CORE, &rlim);
1946 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1947 else st->print("%uk", rlim.rlim_cur >> 10);
1948
1949 st->print(", NPROC ");
1950 getrlimit(RLIMIT_NPROC, &rlim);
1951 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1952 else st->print("%d", rlim.rlim_cur);
1953
1954 st->print(", NOFILE ");
1955 getrlimit(RLIMIT_NOFILE, &rlim);
1956 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1957 else st->print("%d", rlim.rlim_cur);
1958
1959 st->print(", AS ");
1960 getrlimit(RLIMIT_AS, &rlim);
1961 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1962 else st->print("%uk", rlim.rlim_cur >> 10);
1963 st->cr();
1964
1965 // load average
1966 st->print("load average:");
1967 double loadavg[3];
1968 os::loadavg(loadavg, 3);
1969 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
1970 st->cr();
1971 }
1972
1973 void os::print_memory_info(outputStream* st) {
1974
1975 st->print("Memory:");
1976 st->print(" %dk page", os::vm_page_size()>>10);
1977
1978 // values in struct sysinfo are "unsigned long"
1979 struct sysinfo si;
1980 sysinfo(&si);
1981
1982 st->print(", physical " UINT64_FORMAT "k",
1983 os::physical_memory() >> 10);
1984 st->print("(" UINT64_FORMAT "k free)",
1985 os::available_memory() >> 10);
1986 st->print(", swap " UINT64_FORMAT "k",
1987 ((jlong)si.totalswap * si.mem_unit) >> 10);
1988 st->print("(" UINT64_FORMAT "k free)",
1989 ((jlong)si.freeswap * si.mem_unit) >> 10);
1990 st->cr();
1991 }
1992
1993 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
1994 // but they're the same for all the linux arch that we support
1995 // and they're the same for solaris but there's no common place to put this.
1996 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
1997 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
1998 "ILL_COPROC", "ILL_BADSTK" };
1999
2000 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
2001 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
2002 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
2003
2004 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
2005
2006 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
2007
2008 void os::print_siginfo(outputStream* st, void* siginfo) {
2009 st->print("siginfo:");
2010
2011 const int buflen = 100;
2012 char buf[buflen];
2013 siginfo_t *si = (siginfo_t*)siginfo;
2014 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
2015 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
2016 st->print("si_errno=%s", buf);
2017 } else {
2018 st->print("si_errno=%d", si->si_errno);
2019 }
2020 const int c = si->si_code;
2021 assert(c > 0, "unexpected si_code");
2022 switch (si->si_signo) {
2023 case SIGILL:
2024 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
2025 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2026 break;
2027 case SIGFPE:
2028 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
2029 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2030 break;
2031 case SIGSEGV:
2032 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2033 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2034 break;
2035 case SIGBUS:
2036 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2037 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2038 break;
2039 default:
2040 st->print(", si_code=%d", si->si_code);
2041 // no si_addr
2042 }
2043
2044 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2045 UseSharedSpaces) {
2046 FileMapInfo* mapinfo = FileMapInfo::current_info();
2047 if (mapinfo->is_in_shared_space(si->si_addr)) {
2048 st->print("\n\nError accessing class data sharing archive." \
2049 " Mapped file inaccessible during execution, " \
2050 " possible disk/network problem.");
2051 }
2052 }
2053 st->cr();
2054 }
2055
2056
2057 static void print_signal_handler(outputStream* st, int sig,
2058 char* buf, size_t buflen);
2059
2060 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2061 st->print_cr("Signal Handlers:");
2062 print_signal_handler(st, SIGSEGV, buf, buflen);
2063 print_signal_handler(st, SIGBUS , buf, buflen);
2064 print_signal_handler(st, SIGFPE , buf, buflen);
2065 print_signal_handler(st, SIGPIPE, buf, buflen);
2066 print_signal_handler(st, SIGXFSZ, buf, buflen);
2067 print_signal_handler(st, SIGILL , buf, buflen);
2068 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2069 print_signal_handler(st, SR_signum, buf, buflen);
2070 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2071 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2072 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2073 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2074 }
2075
2076 static char saved_jvm_path[MAXPATHLEN] = {0};
2077
2078 // Find the full path to the current module, libjvm.so or libjvm_g.so
2079 void os::jvm_path(char *buf, jint len) {
2080 // Error checking.
2081 if (len < MAXPATHLEN) {
2082 assert(false, "must use a large-enough buffer");
2083 buf[0] = '\0';
2084 return;
2085 }
2086 // Lazy resolve the path to current module.
2087 if (saved_jvm_path[0] != 0) {
2088 strcpy(buf, saved_jvm_path);
2089 return;
2090 }
2091
2092 char dli_fname[MAXPATHLEN];
2093 bool ret = dll_address_to_library_name(
2094 CAST_FROM_FN_PTR(address, os::jvm_path),
2095 dli_fname, sizeof(dli_fname), NULL);
2096 assert(ret != 0, "cannot locate libjvm");
2097 if (realpath(dli_fname, buf) == NULL)
2098 return;
2099
2100 if (strcmp(Arguments::sun_java_launcher(), "gamma") == 0) {
2101 // Support for the gamma launcher. Typical value for buf is
2102 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2103 // the right place in the string, then assume we are installed in a JDK and
2104 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2105 // up the path so it looks like libjvm.so is installed there (append a
2106 // fake suffix hotspot/libjvm.so).
2107 const char *p = buf + strlen(buf) - 1;
2108 for (int count = 0; p > buf && count < 5; ++count) {
2109 for (--p; p > buf && *p != '/'; --p)
2110 /* empty */ ;
2111 }
2112
2113 if (strncmp(p, "/jre/lib/", 9) != 0) {
2114 // Look for JAVA_HOME in the environment.
2115 char* java_home_var = ::getenv("JAVA_HOME");
2116 if (java_home_var != NULL && java_home_var[0] != 0) {
2117 // Check the current module name "libjvm.so" or "libjvm_g.so".
2118 p = strrchr(buf, '/');
2119 assert(strstr(p, "/libjvm") == p, "invalid library name");
2120 p = strstr(p, "_g") ? "_g" : "";
2121
2122 if (realpath(java_home_var, buf) == NULL)
2123 return;
2124 sprintf(buf + strlen(buf), "/jre/lib/%s", cpu_arch);
2125 if (0 == access(buf, F_OK)) {
2126 // Use current module name "libjvm[_g].so" instead of
2127 // "libjvm"debug_only("_g")".so" since for fastdebug version
2128 // we should have "libjvm.so" but debug_only("_g") adds "_g"!
2129 // It is used when we are choosing the HPI library's name
2130 // "libhpi[_g].so" in hpi::initialize_get_interface().
2131 sprintf(buf + strlen(buf), "/hotspot/libjvm%s.so", p);
2132 } else {
2133 // Go back to path of .so
2134 if (realpath(dli_fname, buf) == NULL)
2135 return;
2136 }
2137 }
2138 }
2139 }
2140
2141 strcpy(saved_jvm_path, buf);
2142 }
2143
2144 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2145 // no prefix required, not even "_"
2146 }
2147
2148 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2149 // no suffix required
2150 }
2151
2152 ////////////////////////////////////////////////////////////////////////////////
2153 // sun.misc.Signal support
2154
2155 static volatile jint sigint_count = 0;
2156
2157 static void
2158 UserHandler(int sig, void *siginfo, void *context) {
2159 // 4511530 - sem_post is serialized and handled by the manager thread. When
2160 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2161 // don't want to flood the manager thread with sem_post requests.
2162 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2163 return;
2164
2165 // Ctrl-C is pressed during error reporting, likely because the error
2166 // handler fails to abort. Let VM die immediately.
2167 if (sig == SIGINT && is_error_reported()) {
2168 os::die();
2169 }
2170
2171 os::signal_notify(sig);
2172 }
2173
2174 void* os::user_handler() {
2175 return CAST_FROM_FN_PTR(void*, UserHandler);
2176 }
2177
2178 extern "C" {
2179 typedef void (*sa_handler_t)(int);
2180 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2181 }
2182
2183 void* os::signal(int signal_number, void* handler) {
2184 struct sigaction sigAct, oldSigAct;
2185
2186 sigfillset(&(sigAct.sa_mask));
2187 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2188 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2189
2190 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2191 // -1 means registration failed
2192 return (void *)-1;
2193 }
2194
2195 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2196 }
2197
2198 void os::signal_raise(int signal_number) {
2199 ::raise(signal_number);
2200 }
2201
2202 /*
2203 * The following code is moved from os.cpp for making this
2204 * code platform specific, which it is by its very nature.
2205 */
2206
2207 // Will be modified when max signal is changed to be dynamic
2208 int os::sigexitnum_pd() {
2209 return NSIG;
2210 }
2211
2212 // a counter for each possible signal value
2213 static volatile jint pending_signals[NSIG+1] = { 0 };
2214
2215 // Linux(POSIX) specific hand shaking semaphore.
2216 static sem_t sig_sem;
2217
2218 void os::signal_init_pd() {
2219 // Initialize signal structures
2220 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2221
2222 // Initialize signal semaphore
2223 ::sem_init(&sig_sem, 0, 0);
2224 }
2225
2226 void os::signal_notify(int sig) {
2227 Atomic::inc(&pending_signals[sig]);
2228 ::sem_post(&sig_sem);
2229 }
2230
2231 static int check_pending_signals(bool wait) {
2232 Atomic::store(0, &sigint_count);
2233 for (;;) {
2234 for (int i = 0; i < NSIG + 1; i++) {
2235 jint n = pending_signals[i];
2236 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2237 return i;
2238 }
2239 }
2240 if (!wait) {
2241 return -1;
2242 }
2243 JavaThread *thread = JavaThread::current();
2244 ThreadBlockInVM tbivm(thread);
2245
2246 bool threadIsSuspended;
2247 do {
2248 thread->set_suspend_equivalent();
2249 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2250 ::sem_wait(&sig_sem);
2251
2252 // were we externally suspended while we were waiting?
2253 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2254 if (threadIsSuspended) {
2255 //
2256 // The semaphore has been incremented, but while we were waiting
2257 // another thread suspended us. We don't want to continue running
2258 // while suspended because that would surprise the thread that
2259 // suspended us.
2260 //
2261 ::sem_post(&sig_sem);
2262
2263 thread->java_suspend_self();
2264 }
2265 } while (threadIsSuspended);
2266 }
2267 }
2268
2269 int os::signal_lookup() {
2270 return check_pending_signals(false);
2271 }
2272
2273 int os::signal_wait() {
2274 return check_pending_signals(true);
2275 }
2276
2277 ////////////////////////////////////////////////////////////////////////////////
2278 // Virtual Memory
2279
2280 int os::vm_page_size() {
2281 // Seems redundant as all get out
2282 assert(os::Linux::page_size() != -1, "must call os::init");
2283 return os::Linux::page_size();
2284 }
2285
2286 // Solaris allocates memory by pages.
2287 int os::vm_allocation_granularity() {
2288 assert(os::Linux::page_size() != -1, "must call os::init");
2289 return os::Linux::page_size();
2290 }
2291
2292 // Rationale behind this function:
2293 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2294 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2295 // samples for JITted code. Here we create private executable mapping over the code cache
2296 // and then we can use standard (well, almost, as mapping can change) way to provide
2297 // info for the reporting script by storing timestamp and location of symbol
2298 void linux_wrap_code(char* base, size_t size) {
2299 static volatile jint cnt = 0;
2300
2301 if (!UseOprofile) {
2302 return;
2303 }
2304
2305 char buf[40];
2306 int num = Atomic::add(1, &cnt);
2307
2308 sprintf(buf, "/tmp/hs-vm-%d-%d", os::current_process_id(), num);
2309 unlink(buf);
2310
2311 int fd = open(buf, O_CREAT | O_RDWR, S_IRWXU);
2312
2313 if (fd != -1) {
2314 off_t rv = lseek(fd, size-2, SEEK_SET);
2315 if (rv != (off_t)-1) {
2316 if (write(fd, "", 1) == 1) {
2317 mmap(base, size,
2318 PROT_READ|PROT_WRITE|PROT_EXEC,
2319 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2320 }
2321 }
2322 close(fd);
2323 unlink(buf);
2324 }
2325 }
2326
2327 // NOTE: Linux kernel does not really reserve the pages for us.
2328 // All it does is to check if there are enough free pages
2329 // left at the time of mmap(). This could be a potential
2330 // problem.
2331 bool os::commit_memory(char* addr, size_t size, bool exec) {
2332 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2333 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2334 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2335 return res != (uintptr_t) MAP_FAILED;
2336 }
2337
2338 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
2339 bool exec) {
2340 return commit_memory(addr, size, exec);
2341 }
2342
2343 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { }
2344
2345 void os::free_memory(char *addr, size_t bytes) {
2346 ::mmap(addr, bytes, PROT_READ | PROT_WRITE,
2347 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2348 }
2349
2350 void os::numa_make_global(char *addr, size_t bytes) {
2351 Linux::numa_interleave_memory(addr, bytes);
2352 }
2353
2354 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2355 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2356 }
2357
2358 bool os::numa_topology_changed() { return false; }
2359
2360 size_t os::numa_get_groups_num() {
2361 int max_node = Linux::numa_max_node();
2362 return max_node > 0 ? max_node + 1 : 1;
2363 }
2364
2365 int os::numa_get_group_id() {
2366 int cpu_id = Linux::sched_getcpu();
2367 if (cpu_id != -1) {
2368 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2369 if (lgrp_id != -1) {
2370 return lgrp_id;
2371 }
2372 }
2373 return 0;
2374 }
2375
2376 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2377 for (size_t i = 0; i < size; i++) {
2378 ids[i] = i;
2379 }
2380 return size;
2381 }
2382
2383 bool os::get_page_info(char *start, page_info* info) {
2384 return false;
2385 }
2386
2387 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2388 return end;
2389 }
2390
2391 extern "C" void numa_warn(int number, char *where, ...) { }
2392 extern "C" void numa_error(char *where) { }
2393
2394
2395 // If we are running with libnuma version > 2, then we should
2396 // be trying to use symbols with versions 1.1
2397 // If we are running with earlier version, which did not have symbol versions,
2398 // we should use the base version.
2399 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2400 void *f = dlvsym(handle, name, "libnuma_1.1");
2401 if (f == NULL) {
2402 f = dlsym(handle, name);
2403 }
2404 return f;
2405 }
2406
2407 bool os::Linux::libnuma_init() {
2408 // sched_getcpu() should be in libc.
2409 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2410 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2411
2412 if (sched_getcpu() != -1) { // Does it work?
2413 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2414 if (handle != NULL) {
2415 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2416 libnuma_dlsym(handle, "numa_node_to_cpus")));
2417 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2418 libnuma_dlsym(handle, "numa_max_node")));
2419 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2420 libnuma_dlsym(handle, "numa_available")));
2421 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2422 libnuma_dlsym(handle, "numa_tonode_memory")));
2423 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2424 libnuma_dlsym(handle, "numa_interleave_memory")));
2425
2426
2427 if (numa_available() != -1) {
2428 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2429 // Create a cpu -> node mapping
2430 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true);
2431 rebuild_cpu_to_node_map();
2432 return true;
2433 }
2434 }
2435 }
2436 return false;
2437 }
2438
2439 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2440 // The table is later used in get_node_by_cpu().
2441 void os::Linux::rebuild_cpu_to_node_map() {
2442 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2443 // in libnuma (possible values are starting from 16,
2444 // and continuing up with every other power of 2, but less
2445 // than the maximum number of CPUs supported by kernel), and
2446 // is a subject to change (in libnuma version 2 the requirements
2447 // are more reasonable) we'll just hardcode the number they use
2448 // in the library.
2449 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2450
2451 size_t cpu_num = os::active_processor_count();
2452 size_t cpu_map_size = NCPUS / BitsPerCLong;
2453 size_t cpu_map_valid_size =
2454 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2455
2456 cpu_to_node()->clear();
2457 cpu_to_node()->at_grow(cpu_num - 1);
2458 size_t node_num = numa_get_groups_num();
2459
2460 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size);
2461 for (size_t i = 0; i < node_num; i++) {
2462 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2463 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2464 if (cpu_map[j] != 0) {
2465 for (size_t k = 0; k < BitsPerCLong; k++) {
2466 if (cpu_map[j] & (1UL << k)) {
2467 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2468 }
2469 }
2470 }
2471 }
2472 }
2473 }
2474 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2475 }
2476
2477 int os::Linux::get_node_by_cpu(int cpu_id) {
2478 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2479 return cpu_to_node()->at(cpu_id);
2480 }
2481 return -1;
2482 }
2483
2484 GrowableArray<int>* os::Linux::_cpu_to_node;
2485 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2486 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2487 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2488 os::Linux::numa_available_func_t os::Linux::_numa_available;
2489 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2490 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2491 unsigned long* os::Linux::_numa_all_nodes;
2492
2493 bool os::uncommit_memory(char* addr, size_t size) {
2494 return ::mmap(addr, size, PROT_NONE,
2495 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0)
2496 != MAP_FAILED;
2497 }
2498
2499 // Linux uses a growable mapping for the stack, and if the mapping for
2500 // the stack guard pages is not removed when we detach a thread the
2501 // stack cannot grow beyond the pages where the stack guard was
2502 // mapped. If at some point later in the process the stack expands to
2503 // that point, the Linux kernel cannot expand the stack any further
2504 // because the guard pages are in the way, and a segfault occurs.
2505 //
2506 // However, it's essential not to split the stack region by unmapping
2507 // a region (leaving a hole) that's already part of the stack mapping,
2508 // so if the stack mapping has already grown beyond the guard pages at
2509 // the time we create them, we have to truncate the stack mapping.
2510 // So, we need to know the extent of the stack mapping when
2511 // create_stack_guard_pages() is called.
2512
2513 // Find the bounds of the stack mapping. Return true for success.
2514 //
2515 // We only need this for stacks that are growable: at the time of
2516 // writing thread stacks don't use growable mappings (i.e. those
2517 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2518 // only applies to the main thread.
2519 static bool
2520 get_stack_bounds(uintptr_t *bottom, uintptr_t *top)
2521 {
2522 char filename[sizeof "/proc/" + sizeof "4294967295" + sizeof "/maps"];
2523 snprintf(filename, sizeof filename,
2524 "/proc/%d/maps", syscall(SYS_gettid));
2525 FILE *f = fopen(filename, "r");
2526 if (f == NULL)
2527 return false;
2528
2529 while (!feof(f)) {
2530 size_t dummy;
2531 char *str = NULL;
2532 ssize_t len = getline(&str, &dummy, f);
2533 if (len == -1) {
2534 return false;
2535 }
2536
2537 if (len > 0 && str[len-1] == '\n') {
2538 str[len-1] = 0;
2539 len--;
2540 }
2541
2542 static const char *stack_str = "[stack]";
2543 if (len > (ssize_t)strlen(stack_str)
2544 && (strcmp(str + len - strlen(stack_str), stack_str)
2545 == 0)) {
2546 if (sscanf(str, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
2547 uintptr_t sp = (uintptr_t)__builtin_frame_address(0);
2548 if (sp >= *bottom && sp <= *top) {
2549 free(str);
2550 return true;
2551 }
2552 }
2553 }
2554
2555 free(str);
2556 }
2557
2558 return false;
2559 }
2560
2561 // If the (growable) stack mapping already extends beyond the point
2562 // where we're going to put our guard pages, truncate the mapping at
2563 // that point my munmap()ping it. This ensures that when we later
2564 // munmap() the guard pages we don't leave a hole in the stack
2565 // mapping.
2566 bool os::create_stack_guard_pages(char* addr, size_t size) {
2567 uintptr_t stack_extent, stack_base;
2568 if (get_stack_bounds(&stack_extent, &stack_base)) {
2569 if (stack_extent < (uintptr_t)addr)
2570 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent);
2571 }
2572
2573 return os::commit_memory(addr, size);
2574 }
2575
2576 // If this is a growable mapping, remove the guard pages entirely by
2577 // munmap()ping them. If not, just call uncommit_memory().
2578 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2579 uintptr_t stack_extent, stack_base;
2580 if (get_stack_bounds(&stack_extent, &stack_base)) {
2581 return ::munmap(addr, size) == 0;
2582 }
2583
2584 return os::uncommit_memory(addr, size);
2585 }
2586
2587 static address _highest_vm_reserved_address = NULL;
2588
2589 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2590 // at 'requested_addr'. If there are existing memory mappings at the same
2591 // location, however, they will be overwritten. If 'fixed' is false,
2592 // 'requested_addr' is only treated as a hint, the return value may or
2593 // may not start from the requested address. Unlike Linux mmap(), this
2594 // function returns NULL to indicate failure.
2595 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2596 char * addr;
2597 int flags;
2598
2599 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2600 if (fixed) {
2601 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
2602 flags |= MAP_FIXED;
2603 }
2604
2605 // Map uncommitted pages PROT_READ and PROT_WRITE, change access
2606 // to PROT_EXEC if executable when we commit the page.
2607 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE,
2608 flags, -1, 0);
2609
2610 if (addr != MAP_FAILED) {
2611 // anon_mmap() should only get called during VM initialization,
2612 // don't need lock (actually we can skip locking even it can be called
2613 // from multiple threads, because _highest_vm_reserved_address is just a
2614 // hint about the upper limit of non-stack memory regions.)
2615 if ((address)addr + bytes > _highest_vm_reserved_address) {
2616 _highest_vm_reserved_address = (address)addr + bytes;
2617 }
2618 }
2619
2620 return addr == MAP_FAILED ? NULL : addr;
2621 }
2622
2623 // Don't update _highest_vm_reserved_address, because there might be memory
2624 // regions above addr + size. If so, releasing a memory region only creates
2625 // a hole in the address space, it doesn't help prevent heap-stack collision.
2626 //
2627 static int anon_munmap(char * addr, size_t size) {
2628 return ::munmap(addr, size) == 0;
2629 }
2630
2631 char* os::reserve_memory(size_t bytes, char* requested_addr,
2632 size_t alignment_hint) {
2633 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2634 }
2635
2636 bool os::release_memory(char* addr, size_t size) {
2637 return anon_munmap(addr, size);
2638 }
2639
2640 static address highest_vm_reserved_address() {
2641 return _highest_vm_reserved_address;
2642 }
2643
2644 static bool linux_mprotect(char* addr, size_t size, int prot) {
2645 // Linux wants the mprotect address argument to be page aligned.
2646 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
2647
2648 // According to SUSv3, mprotect() should only be used with mappings
2649 // established by mmap(), and mmap() always maps whole pages. Unaligned
2650 // 'addr' likely indicates problem in the VM (e.g. trying to change
2651 // protection of malloc'ed or statically allocated memory). Check the
2652 // caller if you hit this assert.
2653 assert(addr == bottom, "sanity check");
2654
2655 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
2656 return ::mprotect(bottom, size, prot) == 0;
2657 }
2658
2659 // Set protections specified
2660 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2661 bool is_committed) {
2662 unsigned int p = 0;
2663 switch (prot) {
2664 case MEM_PROT_NONE: p = PROT_NONE; break;
2665 case MEM_PROT_READ: p = PROT_READ; break;
2666 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
2667 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2668 default:
2669 ShouldNotReachHere();
2670 }
2671 // is_committed is unused.
2672 return linux_mprotect(addr, bytes, p);
2673 }
2674
2675 bool os::guard_memory(char* addr, size_t size) {
2676 return linux_mprotect(addr, size, PROT_NONE);
2677 }
2678
2679 bool os::unguard_memory(char* addr, size_t size) {
2680 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2681 }
2682
2683 // Large page support
2684
2685 static size_t _large_page_size = 0;
2686
2687 bool os::large_page_init() {
2688 if (!UseLargePages) return false;
2689
2690 if (LargePageSizeInBytes) {
2691 _large_page_size = LargePageSizeInBytes;
2692 } else {
2693 // large_page_size on Linux is used to round up heap size. x86 uses either
2694 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
2695 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
2696 // page as large as 256M.
2697 //
2698 // Here we try to figure out page size by parsing /proc/meminfo and looking
2699 // for a line with the following format:
2700 // Hugepagesize: 2048 kB
2701 //
2702 // If we can't determine the value (e.g. /proc is not mounted, or the text
2703 // format has been changed), we'll use the largest page size supported by
2704 // the processor.
2705
2706 #ifndef ZERO
2707 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M);
2708 #endif // ZERO
2709
2710 FILE *fp = fopen("/proc/meminfo", "r");
2711 if (fp) {
2712 while (!feof(fp)) {
2713 int x = 0;
2714 char buf[16];
2715 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
2716 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
2717 _large_page_size = x * K;
2718 break;
2719 }
2720 } else {
2721 // skip to next line
2722 for (;;) {
2723 int ch = fgetc(fp);
2724 if (ch == EOF || ch == (int)'\n') break;
2725 }
2726 }
2727 }
2728 fclose(fp);
2729 }
2730 }
2731
2732 const size_t default_page_size = (size_t)Linux::page_size();
2733 if (_large_page_size > default_page_size) {
2734 _page_sizes[0] = _large_page_size;
2735 _page_sizes[1] = default_page_size;
2736 _page_sizes[2] = 0;
2737 }
2738
2739 // Large page support is available on 2.6 or newer kernel, some vendors
2740 // (e.g. Redhat) have backported it to their 2.4 based distributions.
2741 // We optimistically assume the support is available. If later it turns out
2742 // not true, VM will automatically switch to use regular page size.
2743 return true;
2744 }
2745
2746 #ifndef SHM_HUGETLB
2747 #define SHM_HUGETLB 04000
2748 #endif
2749
2750 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
2751 // "exec" is passed in but not used. Creating the shared image for
2752 // the code cache doesn't have an SHM_X executable permission to check.
2753 assert(UseLargePages, "only for large pages");
2754
2755 key_t key = IPC_PRIVATE;
2756 char *addr;
2757
2758 bool warn_on_failure = UseLargePages &&
2759 (!FLAG_IS_DEFAULT(UseLargePages) ||
2760 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
2761 );
2762 char msg[128];
2763
2764 // Create a large shared memory region to attach to based on size.
2765 // Currently, size is the total size of the heap
2766 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
2767 if (shmid == -1) {
2768 // Possible reasons for shmget failure:
2769 // 1. shmmax is too small for Java heap.
2770 // > check shmmax value: cat /proc/sys/kernel/shmmax
2771 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
2772 // 2. not enough large page memory.
2773 // > check available large pages: cat /proc/meminfo
2774 // > increase amount of large pages:
2775 // echo new_value > /proc/sys/vm/nr_hugepages
2776 // Note 1: different Linux may use different name for this property,
2777 // e.g. on Redhat AS-3 it is "hugetlb_pool".
2778 // Note 2: it's possible there's enough physical memory available but
2779 // they are so fragmented after a long run that they can't
2780 // coalesce into large pages. Try to reserve large pages when
2781 // the system is still "fresh".
2782 if (warn_on_failure) {
2783 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
2784 warning(msg);
2785 }
2786 return NULL;
2787 }
2788
2789 // attach to the region
2790 addr = (char*)shmat(shmid, NULL, 0);
2791 int err = errno;
2792
2793 // Remove shmid. If shmat() is successful, the actual shared memory segment
2794 // will be deleted when it's detached by shmdt() or when the process
2795 // terminates. If shmat() is not successful this will remove the shared
2796 // segment immediately.
2797 shmctl(shmid, IPC_RMID, NULL);
2798
2799 if ((intptr_t)addr == -1) {
2800 if (warn_on_failure) {
2801 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
2802 warning(msg);
2803 }
2804 return NULL;
2805 }
2806
2807 return addr;
2808 }
2809
2810 bool os::release_memory_special(char* base, size_t bytes) {
2811 // detaching the SHM segment will also delete it, see reserve_memory_special()
2812 int rslt = shmdt(base);
2813 return rslt == 0;
2814 }
2815
2816 size_t os::large_page_size() {
2817 return _large_page_size;
2818 }
2819
2820 // Linux does not support anonymous mmap with large page memory. The only way
2821 // to reserve large page memory without file backing is through SysV shared
2822 // memory API. The entire memory region is committed and pinned upfront.
2823 // Hopefully this will change in the future...
2824 bool os::can_commit_large_page_memory() {
2825 return false;
2826 }
2827
2828 bool os::can_execute_large_page_memory() {
2829 return false;
2830 }
2831
2832 // Reserve memory at an arbitrary address, only if that area is
2833 // available (and not reserved for something else).
2834
2835 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
2836 const int max_tries = 10;
2837 char* base[max_tries];
2838 size_t size[max_tries];
2839 const size_t gap = 0x000000;
2840
2841 // Assert only that the size is a multiple of the page size, since
2842 // that's all that mmap requires, and since that's all we really know
2843 // about at this low abstraction level. If we need higher alignment,
2844 // we can either pass an alignment to this method or verify alignment
2845 // in one of the methods further up the call chain. See bug 5044738.
2846 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
2847
2848 // Repeatedly allocate blocks until the block is allocated at the
2849 // right spot. Give up after max_tries. Note that reserve_memory() will
2850 // automatically update _highest_vm_reserved_address if the call is
2851 // successful. The variable tracks the highest memory address every reserved
2852 // by JVM. It is used to detect heap-stack collision if running with
2853 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
2854 // space than needed, it could confuse the collision detecting code. To
2855 // solve the problem, save current _highest_vm_reserved_address and
2856 // calculate the correct value before return.
2857 address old_highest = _highest_vm_reserved_address;
2858
2859 // Linux mmap allows caller to pass an address as hint; give it a try first,
2860 // if kernel honors the hint then we can return immediately.
2861 char * addr = anon_mmap(requested_addr, bytes, false);
2862 if (addr == requested_addr) {
2863 return requested_addr;
2864 }
2865
2866 if (addr != NULL) {
2867 // mmap() is successful but it fails to reserve at the requested address
2868 anon_munmap(addr, bytes);
2869 }
2870
2871 int i;
2872 for (i = 0; i < max_tries; ++i) {
2873 base[i] = reserve_memory(bytes);
2874
2875 if (base[i] != NULL) {
2876 // Is this the block we wanted?
2877 if (base[i] == requested_addr) {
2878 size[i] = bytes;
2879 break;
2880 }
2881
2882 // Does this overlap the block we wanted? Give back the overlapped
2883 // parts and try again.
2884
2885 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
2886 if (top_overlap >= 0 && top_overlap < bytes) {
2887 unmap_memory(base[i], top_overlap);
2888 base[i] += top_overlap;
2889 size[i] = bytes - top_overlap;
2890 } else {
2891 size_t bottom_overlap = base[i] + bytes - requested_addr;
2892 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
2893 unmap_memory(requested_addr, bottom_overlap);
2894 size[i] = bytes - bottom_overlap;
2895 } else {
2896 size[i] = bytes;
2897 }
2898 }
2899 }
2900 }
2901
2902 // Give back the unused reserved pieces.
2903
2904 for (int j = 0; j < i; ++j) {
2905 if (base[j] != NULL) {
2906 unmap_memory(base[j], size[j]);
2907 }
2908 }
2909
2910 if (i < max_tries) {
2911 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
2912 return requested_addr;
2913 } else {
2914 _highest_vm_reserved_address = old_highest;
2915 return NULL;
2916 }
2917 }
2918
2919 size_t os::read(int fd, void *buf, unsigned int nBytes) {
2920 return ::read(fd, buf, nBytes);
2921 }
2922
2923 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
2924 // Solaris uses poll(), linux uses park().
2925 // Poll() is likely a better choice, assuming that Thread.interrupt()
2926 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
2927 // SIGSEGV, see 4355769.
2928
2929 const int NANOSECS_PER_MILLISECS = 1000000;
2930
2931 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
2932 assert(thread == Thread::current(), "thread consistency check");
2933
2934 ParkEvent * const slp = thread->_SleepEvent ;
2935 slp->reset() ;
2936 OrderAccess::fence() ;
2937
2938 if (interruptible) {
2939 jlong prevtime = javaTimeNanos();
2940
2941 for (;;) {
2942 if (os::is_interrupted(thread, true)) {
2943 return OS_INTRPT;
2944 }
2945
2946 jlong newtime = javaTimeNanos();
2947
2948 if (newtime - prevtime < 0) {
2949 // time moving backwards, should only happen if no monotonic clock
2950 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2951 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
2952 } else {
2953 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
2954 }
2955
2956 if(millis <= 0) {
2957 return OS_OK;
2958 }
2959
2960 prevtime = newtime;
2961
2962 {
2963 assert(thread->is_Java_thread(), "sanity check");
2964 JavaThread *jt = (JavaThread *) thread;
2965 ThreadBlockInVM tbivm(jt);
2966 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
2967
2968 jt->set_suspend_equivalent();
2969 // cleared by handle_special_suspend_equivalent_condition() or
2970 // java_suspend_self() via check_and_wait_while_suspended()
2971
2972 slp->park(millis);
2973
2974 // were we externally suspended while we were waiting?
2975 jt->check_and_wait_while_suspended();
2976 }
2977 }
2978 } else {
2979 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
2980 jlong prevtime = javaTimeNanos();
2981
2982 for (;;) {
2983 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
2984 // the 1st iteration ...
2985 jlong newtime = javaTimeNanos();
2986
2987 if (newtime - prevtime < 0) {
2988 // time moving backwards, should only happen if no monotonic clock
2989 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2990 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
2991 } else {
2992 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
2993 }
2994
2995 if(millis <= 0) break ;
2996
2997 prevtime = newtime;
2998 slp->park(millis);
2999 }
3000 return OS_OK ;
3001 }
3002 }
3003
3004 int os::naked_sleep() {
3005 // %% make the sleep time an integer flag. for now use 1 millisec.
3006 return os::sleep(Thread::current(), 1, false);
3007 }
3008
3009 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3010 void os::infinite_sleep() {
3011 while (true) { // sleep forever ...
3012 ::sleep(100); // ... 100 seconds at a time
3013 }
3014 }
3015
3016 // Used to convert frequent JVM_Yield() to nops
3017 bool os::dont_yield() {
3018 return DontYieldALot;
3019 }
3020
3021 void os::yield() {
3022 sched_yield();
3023 }
3024
3025 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3026
3027 void os::yield_all(int attempts) {
3028 // Yields to all threads, including threads with lower priorities
3029 // Threads on Linux are all with same priority. The Solaris style
3030 // os::yield_all() with nanosleep(1ms) is not necessary.
3031 sched_yield();
3032 }
3033
3034 // Called from the tight loops to possibly influence time-sharing heuristics
3035 void os::loop_breaker(int attempts) {
3036 os::yield_all(attempts);
3037 }
3038
3039 ////////////////////////////////////////////////////////////////////////////////
3040 // thread priority support
3041
3042 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3043 // only supports dynamic priority, static priority must be zero. For real-time
3044 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3045 // However, for large multi-threaded applications, SCHED_RR is not only slower
3046 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3047 // of 5 runs - Sep 2005).
3048 //
3049 // The following code actually changes the niceness of kernel-thread/LWP. It
3050 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3051 // not the entire user process, and user level threads are 1:1 mapped to kernel
3052 // threads. It has always been the case, but could change in the future. For
3053 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3054 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3055
3056 int os::java_to_os_priority[MaxPriority + 1] = {
3057 19, // 0 Entry should never be used
3058
3059 4, // 1 MinPriority
3060 3, // 2
3061 2, // 3
3062
3063 1, // 4
3064 0, // 5 NormPriority
3065 -1, // 6
3066
3067 -2, // 7
3068 -3, // 8
3069 -4, // 9 NearMaxPriority
3070
3071 -5 // 10 MaxPriority
3072 };
3073
3074 static int prio_init() {
3075 if (ThreadPriorityPolicy == 1) {
3076 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3077 // if effective uid is not root. Perhaps, a more elegant way of doing
3078 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3079 if (geteuid() != 0) {
3080 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3081 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3082 }
3083 ThreadPriorityPolicy = 0;
3084 }
3085 }
3086 return 0;
3087 }
3088
3089 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3090 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3091
3092 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3093 return (ret == 0) ? OS_OK : OS_ERR;
3094 }
3095
3096 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3097 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3098 *priority_ptr = java_to_os_priority[NormPriority];
3099 return OS_OK;
3100 }
3101
3102 errno = 0;
3103 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3104 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3105 }
3106
3107 // Hint to the underlying OS that a task switch would not be good.
3108 // Void return because it's a hint and can fail.
3109 void os::hint_no_preempt() {}
3110
3111 ////////////////////////////////////////////////////////////////////////////////
3112 // suspend/resume support
3113
3114 // the low-level signal-based suspend/resume support is a remnant from the
3115 // old VM-suspension that used to be for java-suspension, safepoints etc,
3116 // within hotspot. Now there is a single use-case for this:
3117 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3118 // that runs in the watcher thread.
3119 // The remaining code is greatly simplified from the more general suspension
3120 // code that used to be used.
3121 //
3122 // The protocol is quite simple:
3123 // - suspend:
3124 // - sends a signal to the target thread
3125 // - polls the suspend state of the osthread using a yield loop
3126 // - target thread signal handler (SR_handler) sets suspend state
3127 // and blocks in sigsuspend until continued
3128 // - resume:
3129 // - sets target osthread state to continue
3130 // - sends signal to end the sigsuspend loop in the SR_handler
3131 //
3132 // Note that the SR_lock plays no role in this suspend/resume protocol.
3133 //
3134
3135 static void resume_clear_context(OSThread *osthread) {
3136 osthread->set_ucontext(NULL);
3137 osthread->set_siginfo(NULL);
3138
3139 // notify the suspend action is completed, we have now resumed
3140 osthread->sr.clear_suspended();
3141 }
3142
3143 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3144 osthread->set_ucontext(context);
3145 osthread->set_siginfo(siginfo);
3146 }
3147
3148 //
3149 // Handler function invoked when a thread's execution is suspended or
3150 // resumed. We have to be careful that only async-safe functions are
3151 // called here (Note: most pthread functions are not async safe and
3152 // should be avoided.)
3153 //
3154 // Note: sigwait() is a more natural fit than sigsuspend() from an
3155 // interface point of view, but sigwait() prevents the signal hander
3156 // from being run. libpthread would get very confused by not having
3157 // its signal handlers run and prevents sigwait()'s use with the
3158 // mutex granting granting signal.
3159 //
3160 // Currently only ever called on the VMThread
3161 //
3162 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3163 // Save and restore errno to avoid confusing native code with EINTR
3164 // after sigsuspend.
3165 int old_errno = errno;
3166
3167 Thread* thread = Thread::current();
3168 OSThread* osthread = thread->osthread();
3169 assert(thread->is_VM_thread(), "Must be VMThread");
3170 // read current suspend action
3171 int action = osthread->sr.suspend_action();
3172 if (action == SR_SUSPEND) {
3173 suspend_save_context(osthread, siginfo, context);
3174
3175 // Notify the suspend action is about to be completed. do_suspend()
3176 // waits until SR_SUSPENDED is set and then returns. We will wait
3177 // here for a resume signal and that completes the suspend-other
3178 // action. do_suspend/do_resume is always called as a pair from
3179 // the same thread - so there are no races
3180
3181 // notify the caller
3182 osthread->sr.set_suspended();
3183
3184 sigset_t suspend_set; // signals for sigsuspend()
3185
3186 // get current set of blocked signals and unblock resume signal
3187 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3188 sigdelset(&suspend_set, SR_signum);
3189
3190 // wait here until we are resumed
3191 do {
3192 sigsuspend(&suspend_set);
3193 // ignore all returns until we get a resume signal
3194 } while (osthread->sr.suspend_action() != SR_CONTINUE);
3195
3196 resume_clear_context(osthread);
3197
3198 } else {
3199 assert(action == SR_CONTINUE, "unexpected sr action");
3200 // nothing special to do - just leave the handler
3201 }
3202
3203 errno = old_errno;
3204 }
3205
3206
3207 static int SR_initialize() {
3208 struct sigaction act;
3209 char *s;
3210 /* Get signal number to use for suspend/resume */
3211 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
3212 int sig = ::strtol(s, 0, 10);
3213 if (sig > 0 || sig < _NSIG) {
3214 SR_signum = sig;
3215 }
3216 }
3217
3218 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
3219 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
3220
3221 sigemptyset(&SR_sigset);
3222 sigaddset(&SR_sigset, SR_signum);
3223
3224 /* Set up signal handler for suspend/resume */
3225 act.sa_flags = SA_RESTART|SA_SIGINFO;
3226 act.sa_handler = (void (*)(int)) SR_handler;
3227
3228 // SR_signum is blocked by default.
3229 // 4528190 - We also need to block pthread restart signal (32 on all
3230 // supported Linux platforms). Note that LinuxThreads need to block
3231 // this signal for all threads to work properly. So we don't have
3232 // to use hard-coded signal number when setting up the mask.
3233 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
3234
3235 if (sigaction(SR_signum, &act, 0) == -1) {
3236 return -1;
3237 }
3238
3239 // Save signal flag
3240 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
3241 return 0;
3242 }
3243
3244 static int SR_finalize() {
3245 return 0;
3246 }
3247
3248
3249 // returns true on success and false on error - really an error is fatal
3250 // but this seems the normal response to library errors
3251 static bool do_suspend(OSThread* osthread) {
3252 // mark as suspended and send signal
3253 osthread->sr.set_suspend_action(SR_SUSPEND);
3254 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3255 assert_status(status == 0, status, "pthread_kill");
3256
3257 // check status and wait until notified of suspension
3258 if (status == 0) {
3259 for (int i = 0; !osthread->sr.is_suspended(); i++) {
3260 os::yield_all(i);
3261 }
3262 osthread->sr.set_suspend_action(SR_NONE);
3263 return true;
3264 }
3265 else {
3266 osthread->sr.set_suspend_action(SR_NONE);
3267 return false;
3268 }
3269 }
3270
3271 static void do_resume(OSThread* osthread) {
3272 assert(osthread->sr.is_suspended(), "thread should be suspended");
3273 osthread->sr.set_suspend_action(SR_CONTINUE);
3274
3275 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3276 assert_status(status == 0, status, "pthread_kill");
3277 // check status and wait unit notified of resumption
3278 if (status == 0) {
3279 for (int i = 0; osthread->sr.is_suspended(); i++) {
3280 os::yield_all(i);
3281 }
3282 }
3283 osthread->sr.set_suspend_action(SR_NONE);
3284 }
3285
3286 ////////////////////////////////////////////////////////////////////////////////
3287 // interrupt support
3288
3289 void os::interrupt(Thread* thread) {
3290 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3291 "possibility of dangling Thread pointer");
3292
3293 OSThread* osthread = thread->osthread();
3294
3295 if (!osthread->interrupted()) {
3296 osthread->set_interrupted(true);
3297 // More than one thread can get here with the same value of osthread,
3298 // resulting in multiple notifications. We do, however, want the store
3299 // to interrupted() to be visible to other threads before we execute unpark().
3300 OrderAccess::fence();
3301 ParkEvent * const slp = thread->_SleepEvent ;
3302 if (slp != NULL) slp->unpark() ;
3303 }
3304
3305 // For JSR166. Unpark even if interrupt status already was set
3306 if (thread->is_Java_thread())
3307 ((JavaThread*)thread)->parker()->unpark();
3308
3309 ParkEvent * ev = thread->_ParkEvent ;
3310 if (ev != NULL) ev->unpark() ;
3311
3312 }
3313
3314 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
3315 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3316 "possibility of dangling Thread pointer");
3317
3318 OSThread* osthread = thread->osthread();
3319
3320 bool interrupted = osthread->interrupted();
3321
3322 if (interrupted && clear_interrupted) {
3323 osthread->set_interrupted(false);
3324 // consider thread->_SleepEvent->reset() ... optional optimization
3325 }
3326
3327 return interrupted;
3328 }
3329
3330 ///////////////////////////////////////////////////////////////////////////////////
3331 // signal handling (except suspend/resume)
3332
3333 // This routine may be used by user applications as a "hook" to catch signals.
3334 // The user-defined signal handler must pass unrecognized signals to this
3335 // routine, and if it returns true (non-zero), then the signal handler must
3336 // return immediately. If the flag "abort_if_unrecognized" is true, then this
3337 // routine will never retun false (zero), but instead will execute a VM panic
3338 // routine kill the process.
3339 //
3340 // If this routine returns false, it is OK to call it again. This allows
3341 // the user-defined signal handler to perform checks either before or after
3342 // the VM performs its own checks. Naturally, the user code would be making
3343 // a serious error if it tried to handle an exception (such as a null check
3344 // or breakpoint) that the VM was generating for its own correct operation.
3345 //
3346 // This routine may recognize any of the following kinds of signals:
3347 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
3348 // It should be consulted by handlers for any of those signals.
3349 //
3350 // The caller of this routine must pass in the three arguments supplied
3351 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
3352 // field of the structure passed to sigaction(). This routine assumes that
3353 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
3354 //
3355 // Note that the VM will print warnings if it detects conflicting signal
3356 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
3357 //
3358 extern "C" int
3359 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
3360 void* ucontext, int abort_if_unrecognized);
3361
3362 void signalHandler(int sig, siginfo_t* info, void* uc) {
3363 assert(info != NULL && uc != NULL, "it must be old kernel");
3364 JVM_handle_linux_signal(sig, info, uc, true);
3365 }
3366
3367
3368 // This boolean allows users to forward their own non-matching signals
3369 // to JVM_handle_linux_signal, harmlessly.
3370 bool os::Linux::signal_handlers_are_installed = false;
3371
3372 // For signal-chaining
3373 struct sigaction os::Linux::sigact[MAXSIGNUM];
3374 unsigned int os::Linux::sigs = 0;
3375 bool os::Linux::libjsig_is_loaded = false;
3376 typedef struct sigaction *(*get_signal_t)(int);
3377 get_signal_t os::Linux::get_signal_action = NULL;
3378
3379 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
3380 struct sigaction *actp = NULL;
3381
3382 if (libjsig_is_loaded) {
3383 // Retrieve the old signal handler from libjsig
3384 actp = (*get_signal_action)(sig);
3385 }
3386 if (actp == NULL) {
3387 // Retrieve the preinstalled signal handler from jvm
3388 actp = get_preinstalled_handler(sig);
3389 }
3390
3391 return actp;
3392 }
3393
3394 static bool call_chained_handler(struct sigaction *actp, int sig,
3395 siginfo_t *siginfo, void *context) {
3396 // Call the old signal handler
3397 if (actp->sa_handler == SIG_DFL) {
3398 // It's more reasonable to let jvm treat it as an unexpected exception
3399 // instead of taking the default action.
3400 return false;
3401 } else if (actp->sa_handler != SIG_IGN) {
3402 if ((actp->sa_flags & SA_NODEFER) == 0) {
3403 // automaticlly block the signal
3404 sigaddset(&(actp->sa_mask), sig);
3405 }
3406
3407 sa_handler_t hand;
3408 sa_sigaction_t sa;
3409 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3410 // retrieve the chained handler
3411 if (siginfo_flag_set) {
3412 sa = actp->sa_sigaction;
3413 } else {
3414 hand = actp->sa_handler;
3415 }
3416
3417 if ((actp->sa_flags & SA_RESETHAND) != 0) {
3418 actp->sa_handler = SIG_DFL;
3419 }
3420
3421 // try to honor the signal mask
3422 sigset_t oset;
3423 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3424
3425 // call into the chained handler
3426 if (siginfo_flag_set) {
3427 (*sa)(sig, siginfo, context);
3428 } else {
3429 (*hand)(sig);
3430 }
3431
3432 // restore the signal mask
3433 pthread_sigmask(SIG_SETMASK, &oset, 0);
3434 }
3435 // Tell jvm's signal handler the signal is taken care of.
3436 return true;
3437 }
3438
3439 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3440 bool chained = false;
3441 // signal-chaining
3442 if (UseSignalChaining) {
3443 struct sigaction *actp = get_chained_signal_action(sig);
3444 if (actp != NULL) {
3445 chained = call_chained_handler(actp, sig, siginfo, context);
3446 }
3447 }
3448 return chained;
3449 }
3450
3451 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
3452 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
3453 return &sigact[sig];
3454 }
3455 return NULL;
3456 }
3457
3458 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3459 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3460 sigact[sig] = oldAct;
3461 sigs |= (unsigned int)1 << sig;
3462 }
3463
3464 // for diagnostic
3465 int os::Linux::sigflags[MAXSIGNUM];
3466
3467 int os::Linux::get_our_sigflags(int sig) {
3468 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3469 return sigflags[sig];
3470 }
3471
3472 void os::Linux::set_our_sigflags(int sig, int flags) {
3473 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3474 sigflags[sig] = flags;
3475 }
3476
3477 void os::Linux::set_signal_handler(int sig, bool set_installed) {
3478 // Check for overwrite.
3479 struct sigaction oldAct;
3480 sigaction(sig, (struct sigaction*)NULL, &oldAct);
3481
3482 void* oldhand = oldAct.sa_sigaction
3483 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3484 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3485 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3486 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3487 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3488 if (AllowUserSignalHandlers || !set_installed) {
3489 // Do not overwrite; user takes responsibility to forward to us.
3490 return;
3491 } else if (UseSignalChaining) {
3492 // save the old handler in jvm
3493 save_preinstalled_handler(sig, oldAct);
3494 // libjsig also interposes the sigaction() call below and saves the
3495 // old sigaction on it own.
3496 } else {
3497 fatal2("Encountered unexpected pre-existing sigaction handler %#lx for signal %d.", (long)oldhand, sig);
3498 }
3499 }
3500
3501 struct sigaction sigAct;
3502 sigfillset(&(sigAct.sa_mask));
3503 sigAct.sa_handler = SIG_DFL;
3504 if (!set_installed) {
3505 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3506 } else {
3507 sigAct.sa_sigaction = signalHandler;
3508 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3509 }
3510 // Save flags, which are set by ours
3511 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3512 sigflags[sig] = sigAct.sa_flags;
3513
3514 int ret = sigaction(sig, &sigAct, &oldAct);
3515 assert(ret == 0, "check");
3516
3517 void* oldhand2 = oldAct.sa_sigaction
3518 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3519 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3520 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3521 }
3522
3523 // install signal handlers for signals that HotSpot needs to
3524 // handle in order to support Java-level exception handling.
3525
3526 void os::Linux::install_signal_handlers() {
3527 if (!signal_handlers_are_installed) {
3528 signal_handlers_are_installed = true;
3529
3530 // signal-chaining
3531 typedef void (*signal_setting_t)();
3532 signal_setting_t begin_signal_setting = NULL;
3533 signal_setting_t end_signal_setting = NULL;
3534 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3535 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3536 if (begin_signal_setting != NULL) {
3537 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3538 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3539 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3540 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3541 libjsig_is_loaded = true;
3542 assert(UseSignalChaining, "should enable signal-chaining");
3543 }
3544 if (libjsig_is_loaded) {
3545 // Tell libjsig jvm is setting signal handlers
3546 (*begin_signal_setting)();
3547 }
3548
3549 set_signal_handler(SIGSEGV, true);
3550 set_signal_handler(SIGPIPE, true);
3551 set_signal_handler(SIGBUS, true);
3552 set_signal_handler(SIGILL, true);
3553 set_signal_handler(SIGFPE, true);
3554 set_signal_handler(SIGXFSZ, true);
3555
3556 if (libjsig_is_loaded) {
3557 // Tell libjsig jvm finishes setting signal handlers
3558 (*end_signal_setting)();
3559 }
3560
3561 // We don't activate signal checker if libjsig is in place, we trust ourselves
3562 // and if UserSignalHandler is installed all bets are off
3563 if (CheckJNICalls) {
3564 if (libjsig_is_loaded) {
3565 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3566 check_signals = false;
3567 }
3568 if (AllowUserSignalHandlers) {
3569 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3570 check_signals = false;
3571 }
3572 }
3573 }
3574 }
3575
3576 // This is the fastest way to get thread cpu time on Linux.
3577 // Returns cpu time (user+sys) for any thread, not only for current.
3578 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
3579 // It might work on 2.6.10+ with a special kernel/glibc patch.
3580 // For reference, please, see IEEE Std 1003.1-2004:
3581 // http://www.unix.org/single_unix_specification
3582
3583 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
3584 struct timespec tp;
3585 int rc = os::Linux::clock_gettime(clockid, &tp);
3586 assert(rc == 0, "clock_gettime is expected to return 0 code");
3587
3588 return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec;
3589 }
3590
3591 /////
3592 // glibc on Linux platform uses non-documented flag
3593 // to indicate, that some special sort of signal
3594 // trampoline is used.
3595 // We will never set this flag, and we should
3596 // ignore this flag in our diagnostic
3597 #ifdef SIGNIFICANT_SIGNAL_MASK
3598 #undef SIGNIFICANT_SIGNAL_MASK
3599 #endif
3600 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3601
3602 static const char* get_signal_handler_name(address handler,
3603 char* buf, int buflen) {
3604 int offset;
3605 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3606 if (found) {
3607 // skip directory names
3608 const char *p1, *p2;
3609 p1 = buf;
3610 size_t len = strlen(os::file_separator());
3611 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3612 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3613 } else {
3614 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3615 }
3616 return buf;
3617 }
3618
3619 static void print_signal_handler(outputStream* st, int sig,
3620 char* buf, size_t buflen) {
3621 struct sigaction sa;
3622
3623 sigaction(sig, NULL, &sa);
3624
3625 // See comment for SIGNIFICANT_SIGNAL_MASK define
3626 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3627
3628 st->print("%s: ", os::exception_name(sig, buf, buflen));
3629
3630 address handler = (sa.sa_flags & SA_SIGINFO)
3631 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3632 : CAST_FROM_FN_PTR(address, sa.sa_handler);
3633
3634 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3635 st->print("SIG_DFL");
3636 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3637 st->print("SIG_IGN");
3638 } else {
3639 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3640 }
3641
3642 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
3643
3644 address rh = VMError::get_resetted_sighandler(sig);
3645 // May be, handler was resetted by VMError?
3646 if(rh != NULL) {
3647 handler = rh;
3648 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3649 }
3650
3651 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
3652
3653 // Check: is it our handler?
3654 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3655 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3656 // It is our signal handler
3657 // check for flags, reset system-used one!
3658 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
3659 st->print(
3660 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3661 os::Linux::get_our_sigflags(sig));
3662 }
3663 }
3664 st->cr();
3665 }
3666
3667
3668 #define DO_SIGNAL_CHECK(sig) \
3669 if (!sigismember(&check_signal_done, sig)) \
3670 os::Linux::check_signal_handler(sig)
3671
3672 // This method is a periodic task to check for misbehaving JNI applications
3673 // under CheckJNI, we can add any periodic checks here
3674
3675 void os::run_periodic_checks() {
3676
3677 if (check_signals == false) return;
3678
3679 // SEGV and BUS if overridden could potentially prevent
3680 // generation of hs*.log in the event of a crash, debugging
3681 // such a case can be very challenging, so we absolutely
3682 // check the following for a good measure:
3683 DO_SIGNAL_CHECK(SIGSEGV);
3684 DO_SIGNAL_CHECK(SIGILL);
3685 DO_SIGNAL_CHECK(SIGFPE);
3686 DO_SIGNAL_CHECK(SIGBUS);
3687 DO_SIGNAL_CHECK(SIGPIPE);
3688 DO_SIGNAL_CHECK(SIGXFSZ);
3689
3690
3691 // ReduceSignalUsage allows the user to override these handlers
3692 // see comments at the very top and jvm_solaris.h
3693 if (!ReduceSignalUsage) {
3694 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
3695 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
3696 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
3697 DO_SIGNAL_CHECK(BREAK_SIGNAL);
3698 }
3699
3700 DO_SIGNAL_CHECK(SR_signum);
3701 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
3702 }
3703
3704 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
3705
3706 static os_sigaction_t os_sigaction = NULL;
3707
3708 void os::Linux::check_signal_handler(int sig) {
3709 char buf[O_BUFLEN];
3710 address jvmHandler = NULL;
3711
3712
3713 struct sigaction act;
3714 if (os_sigaction == NULL) {
3715 // only trust the default sigaction, in case it has been interposed
3716 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
3717 if (os_sigaction == NULL) return;
3718 }
3719
3720 os_sigaction(sig, (struct sigaction*)NULL, &act);
3721
3722
3723 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3724
3725 address thisHandler = (act.sa_flags & SA_SIGINFO)
3726 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
3727 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
3728
3729
3730 switch(sig) {
3731 case SIGSEGV:
3732 case SIGBUS:
3733 case SIGFPE:
3734 case SIGPIPE:
3735 case SIGILL:
3736 case SIGXFSZ:
3737 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
3738 break;
3739
3740 case SHUTDOWN1_SIGNAL:
3741 case SHUTDOWN2_SIGNAL:
3742 case SHUTDOWN3_SIGNAL:
3743 case BREAK_SIGNAL:
3744 jvmHandler = (address)user_handler();
3745 break;
3746
3747 case INTERRUPT_SIGNAL:
3748 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
3749 break;
3750
3751 default:
3752 if (sig == SR_signum) {
3753 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
3754 } else {
3755 return;
3756 }
3757 break;
3758 }
3759
3760 if (thisHandler != jvmHandler) {
3761 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
3762 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
3763 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
3764 // No need to check this sig any longer
3765 sigaddset(&check_signal_done, sig);
3766 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
3767 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
3768 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
3769 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
3770 // No need to check this sig any longer
3771 sigaddset(&check_signal_done, sig);
3772 }
3773
3774 // Dump all the signal
3775 if (sigismember(&check_signal_done, sig)) {
3776 print_signal_handlers(tty, buf, O_BUFLEN);
3777 }
3778 }
3779
3780 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
3781
3782 extern bool signal_name(int signo, char* buf, size_t len);
3783
3784 const char* os::exception_name(int exception_code, char* buf, size_t size) {
3785 if (0 < exception_code && exception_code <= SIGRTMAX) {
3786 // signal
3787 if (!signal_name(exception_code, buf, size)) {
3788 jio_snprintf(buf, size, "SIG%d", exception_code);
3789 }
3790 return buf;
3791 } else {
3792 return NULL;
3793 }
3794 }
3795
3796 // this is called _before_ the most of global arguments have been parsed
3797 void os::init(void) {
3798 char dummy; /* used to get a guess on initial stack address */
3799 // first_hrtime = gethrtime();
3800
3801 // With LinuxThreads the JavaMain thread pid (primordial thread)
3802 // is different than the pid of the java launcher thread.
3803 // So, on Linux, the launcher thread pid is passed to the VM
3804 // via the sun.java.launcher.pid property.
3805 // Use this property instead of getpid() if it was correctly passed.
3806 // See bug 6351349.
3807 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
3808
3809 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
3810
3811 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
3812
3813 init_random(1234567);
3814
3815 ThreadCritical::initialize();
3816
3817 Linux::set_page_size(sysconf(_SC_PAGESIZE));
3818 if (Linux::page_size() == -1) {
3819 fatal1("os_linux.cpp: os::init: sysconf failed (%s)", strerror(errno));
3820 }
3821 init_page_sizes((size_t) Linux::page_size());
3822
3823 Linux::initialize_system_info();
3824
3825 // main_thread points to the aboriginal thread
3826 Linux::_main_thread = pthread_self();
3827
3828 Linux::clock_init();
3829 initial_time_count = os::elapsed_counter();
3830 pthread_mutex_init(&dl_mutex, NULL);
3831 }
3832
3833 // To install functions for atexit system call
3834 extern "C" {
3835 static void perfMemory_exit_helper() {
3836 perfMemory_exit();
3837 }
3838 }
3839
3840 // this is called _after_ the global arguments have been parsed
3841 jint os::init_2(void)
3842 {
3843 Linux::fast_thread_clock_init();
3844
3845 // Allocate a single page and mark it as readable for safepoint polling
3846 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
3847 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
3848
3849 os::set_polling_page( polling_page );
3850
3851 #ifndef PRODUCT
3852 if(Verbose && PrintMiscellaneous)
3853 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
3854 #endif
3855
3856 if (!UseMembar) {
3857 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
3858 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page");
3859 os::set_memory_serialize_page( mem_serialize_page );
3860
3861 #ifndef PRODUCT
3862 if(Verbose && PrintMiscellaneous)
3863 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
3864 #endif
3865 }
3866
3867 FLAG_SET_DEFAULT(UseLargePages, os::large_page_init());
3868
3869 // initialize suspend/resume support - must do this before signal_sets_init()
3870 if (SR_initialize() != 0) {
3871 perror("SR_initialize failed");
3872 return JNI_ERR;
3873 }
3874
3875 Linux::signal_sets_init();
3876 Linux::install_signal_handlers();
3877
3878 size_t threadStackSizeInBytes = ThreadStackSize * K;
3879 if (threadStackSizeInBytes != 0 &&
3880 threadStackSizeInBytes < Linux::min_stack_allowed) {
3881 tty->print_cr("\nThe stack size specified is too small, "
3882 "Specify at least %dk",
3883 Linux::min_stack_allowed / K);
3884 return JNI_ERR;
3885 }
3886
3887 // Make the stack size a multiple of the page size so that
3888 // the yellow/red zones can be guarded.
3889 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
3890 vm_page_size()));
3891
3892 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
3893
3894 Linux::libpthread_init();
3895 if (PrintMiscellaneous && (Verbose || WizardMode)) {
3896 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
3897 Linux::glibc_version(), Linux::libpthread_version(),
3898 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
3899 }
3900
3901 if (UseNUMA) {
3902 if (!Linux::libnuma_init()) {
3903 UseNUMA = false;
3904 } else {
3905 if ((Linux::numa_max_node() < 1)) {
3906 // There's only one node(they start from 0), disable NUMA.
3907 UseNUMA = false;
3908 }
3909 }
3910 if (!UseNUMA && ForceNUMA) {
3911 UseNUMA = true;
3912 }
3913 }
3914
3915 if (MaxFDLimit) {
3916 // set the number of file descriptors to max. print out error
3917 // if getrlimit/setrlimit fails but continue regardless.
3918 struct rlimit nbr_files;
3919 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
3920 if (status != 0) {
3921 if (PrintMiscellaneous && (Verbose || WizardMode))
3922 perror("os::init_2 getrlimit failed");
3923 } else {
3924 nbr_files.rlim_cur = nbr_files.rlim_max;
3925 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
3926 if (status != 0) {
3927 if (PrintMiscellaneous && (Verbose || WizardMode))
3928 perror("os::init_2 setrlimit failed");
3929 }
3930 }
3931 }
3932
3933 // Initialize lock used to serialize thread creation (see os::create_thread)
3934 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
3935
3936 // Initialize HPI.
3937 jint hpi_result = hpi::initialize();
3938 if (hpi_result != JNI_OK) {
3939 tty->print_cr("There was an error trying to initialize the HPI library.");
3940 return hpi_result;
3941 }
3942
3943 // at-exit methods are called in the reverse order of their registration.
3944 // atexit functions are called on return from main or as a result of a
3945 // call to exit(3C). There can be only 32 of these functions registered
3946 // and atexit() does not set errno.
3947
3948 if (PerfAllowAtExitRegistration) {
3949 // only register atexit functions if PerfAllowAtExitRegistration is set.
3950 // atexit functions can be delayed until process exit time, which
3951 // can be problematic for embedded VM situations. Embedded VMs should
3952 // call DestroyJavaVM() to assure that VM resources are released.
3953
3954 // note: perfMemory_exit_helper atexit function may be removed in
3955 // the future if the appropriate cleanup code can be added to the
3956 // VM_Exit VMOperation's doit method.
3957 if (atexit(perfMemory_exit_helper) != 0) {
3958 warning("os::init2 atexit(perfMemory_exit_helper) failed");
3959 }
3960 }
3961
3962 // initialize thread priority policy
3963 prio_init();
3964
3965 return JNI_OK;
3966 }
3967
3968 // Mark the polling page as unreadable
3969 void os::make_polling_page_unreadable(void) {
3970 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
3971 fatal("Could not disable polling page");
3972 };
3973
3974 // Mark the polling page as readable
3975 void os::make_polling_page_readable(void) {
3976 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
3977 fatal("Could not enable polling page");
3978 }
3979 };
3980
3981 int os::active_processor_count() {
3982 // Linux doesn't yet have a (official) notion of processor sets,
3983 // so just return the number of online processors.
3984 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
3985 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
3986 return online_cpus;
3987 }
3988
3989 bool os::distribute_processes(uint length, uint* distribution) {
3990 // Not yet implemented.
3991 return false;
3992 }
3993
3994 bool os::bind_to_processor(uint processor_id) {
3995 // Not yet implemented.
3996 return false;
3997 }
3998
3999 ///
4000
4001 // Suspends the target using the signal mechanism and then grabs the PC before
4002 // resuming the target. Used by the flat-profiler only
4003 ExtendedPC os::get_thread_pc(Thread* thread) {
4004 // Make sure that it is called by the watcher for the VMThread
4005 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4006 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4007
4008 ExtendedPC epc;
4009
4010 OSThread* osthread = thread->osthread();
4011 if (do_suspend(osthread)) {
4012 if (osthread->ucontext() != NULL) {
4013 epc = os::Linux::ucontext_get_pc(osthread->ucontext());
4014 } else {
4015 // NULL context is unexpected, double-check this is the VMThread
4016 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4017 }
4018 do_resume(osthread);
4019 }
4020 // failure means pthread_kill failed for some reason - arguably this is
4021 // a fatal problem, but such problems are ignored elsewhere
4022
4023 return epc;
4024 }
4025
4026 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4027 {
4028 if (is_NPTL()) {
4029 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4030 } else {
4031 #ifndef IA64
4032 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4033 // word back to default 64bit precision if condvar is signaled. Java
4034 // wants 53bit precision. Save and restore current value.
4035 int fpu = get_fpu_control_word();
4036 #endif // IA64
4037 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4038 #ifndef IA64
4039 set_fpu_control_word(fpu);
4040 #endif // IA64
4041 return status;
4042 }
4043 }
4044
4045 ////////////////////////////////////////////////////////////////////////////////
4046 // debug support
4047
4048 #ifndef PRODUCT
4049 static address same_page(address x, address y) {
4050 int page_bits = -os::vm_page_size();
4051 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
4052 return x;
4053 else if (x > y)
4054 return (address)(intptr_t(y) | ~page_bits) + 1;
4055 else
4056 return (address)(intptr_t(y) & page_bits);
4057 }
4058
4059 bool os::find(address addr) {
4060 Dl_info dlinfo;
4061 memset(&dlinfo, 0, sizeof(dlinfo));
4062 if (dladdr(addr, &dlinfo)) {
4063 tty->print(PTR_FORMAT ": ", addr);
4064 if (dlinfo.dli_sname != NULL) {
4065 tty->print("%s+%#x", dlinfo.dli_sname,
4066 addr - (intptr_t)dlinfo.dli_saddr);
4067 } else if (dlinfo.dli_fname) {
4068 tty->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4069 } else {
4070 tty->print("<absolute address>");
4071 }
4072 if (dlinfo.dli_fname) {
4073 tty->print(" in %s", dlinfo.dli_fname);
4074 }
4075 if (dlinfo.dli_fbase) {
4076 tty->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4077 }
4078 tty->cr();
4079
4080 if (Verbose) {
4081 // decode some bytes around the PC
4082 address begin = same_page(addr-40, addr);
4083 address end = same_page(addr+40, addr);
4084 address lowest = (address) dlinfo.dli_sname;
4085 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4086 if (begin < lowest) begin = lowest;
4087 Dl_info dlinfo2;
4088 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
4089 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
4090 end = (address) dlinfo2.dli_saddr;
4091 Disassembler::decode(begin, end);
4092 }
4093 return true;
4094 }
4095 return false;
4096 }
4097
4098 #endif
4099
4100 ////////////////////////////////////////////////////////////////////////////////
4101 // misc
4102
4103 // This does not do anything on Linux. This is basically a hook for being
4104 // able to use structured exception handling (thread-local exception filters)
4105 // on, e.g., Win32.
4106 void
4107 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
4108 JavaCallArguments* args, Thread* thread) {
4109 f(value, method, args, thread);
4110 }
4111
4112 void os::print_statistics() {
4113 }
4114
4115 int os::message_box(const char* title, const char* message) {
4116 int i;
4117 fdStream err(defaultStream::error_fd());
4118 for (i = 0; i < 78; i++) err.print_raw("=");
4119 err.cr();
4120 err.print_raw_cr(title);
4121 for (i = 0; i < 78; i++) err.print_raw("-");
4122 err.cr();
4123 err.print_raw_cr(message);
4124 for (i = 0; i < 78; i++) err.print_raw("=");
4125 err.cr();
4126
4127 char buf[16];
4128 // Prevent process from exiting upon "read error" without consuming all CPU
4129 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
4130
4131 return buf[0] == 'y' || buf[0] == 'Y';
4132 }
4133
4134 int os::stat(const char *path, struct stat *sbuf) {
4135 char pathbuf[MAX_PATH];
4136 if (strlen(path) > MAX_PATH - 1) {
4137 errno = ENAMETOOLONG;
4138 return -1;
4139 }
4140 hpi::native_path(strcpy(pathbuf, path));
4141 return ::stat(pathbuf, sbuf);
4142 }
4143
4144 bool os::check_heap(bool force) {
4145 return true;
4146 }
4147
4148 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
4149 return ::vsnprintf(buf, count, format, args);
4150 }
4151
4152 // Is a (classpath) directory empty?
4153 bool os::dir_is_empty(const char* path) {
4154 DIR *dir = NULL;
4155 struct dirent *ptr;
4156
4157 dir = opendir(path);
4158 if (dir == NULL) return true;
4159
4160 /* Scan the directory */
4161 bool result = true;
4162 char buf[sizeof(struct dirent) + MAX_PATH];
4163 while (result && (ptr = ::readdir(dir)) != NULL) {
4164 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
4165 result = false;
4166 }
4167 }
4168 closedir(dir);
4169 return result;
4170 }
4171
4172 // create binary file, rewriting existing file if required
4173 int os::create_binary_file(const char* path, bool rewrite_existing) {
4174 int oflags = O_WRONLY | O_CREAT;
4175 if (!rewrite_existing) {
4176 oflags |= O_EXCL;
4177 }
4178 return ::open64(path, oflags, S_IREAD | S_IWRITE);
4179 }
4180
4181 // return current position of file pointer
4182 jlong os::current_file_offset(int fd) {
4183 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
4184 }
4185
4186 // move file pointer to the specified offset
4187 jlong os::seek_to_file_offset(int fd, jlong offset) {
4188 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
4189 }
4190
4191 // Map a block of memory.
4192 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
4193 char *addr, size_t bytes, bool read_only,
4194 bool allow_exec) {
4195 int prot;
4196 int flags;
4197
4198 if (read_only) {
4199 prot = PROT_READ;
4200 flags = MAP_SHARED;
4201 } else {
4202 prot = PROT_READ | PROT_WRITE;
4203 flags = MAP_PRIVATE;
4204 }
4205
4206 if (allow_exec) {
4207 prot |= PROT_EXEC;
4208 }
4209
4210 if (addr != NULL) {
4211 flags |= MAP_FIXED;
4212 }
4213
4214 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
4215 fd, file_offset);
4216 if (mapped_address == MAP_FAILED) {
4217 return NULL;
4218 }
4219 return mapped_address;
4220 }
4221
4222
4223 // Remap a block of memory.
4224 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
4225 char *addr, size_t bytes, bool read_only,
4226 bool allow_exec) {
4227 // same as map_memory() on this OS
4228 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4229 allow_exec);
4230 }
4231
4232
4233 // Unmap a block of memory.
4234 bool os::unmap_memory(char* addr, size_t bytes) {
4235 return munmap(addr, bytes) == 0;
4236 }
4237
4238 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
4239
4240 static clockid_t thread_cpu_clockid(Thread* thread) {
4241 pthread_t tid = thread->osthread()->pthread_id();
4242 clockid_t clockid;
4243
4244 // Get thread clockid
4245 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
4246 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
4247 return clockid;
4248 }
4249
4250 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4251 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4252 // of a thread.
4253 //
4254 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4255 // the fast estimate available on the platform.
4256
4257 jlong os::current_thread_cpu_time() {
4258 if (os::Linux::supports_fast_thread_cpu_time()) {
4259 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4260 } else {
4261 // return user + sys since the cost is the same
4262 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
4263 }
4264 }
4265
4266 jlong os::thread_cpu_time(Thread* thread) {
4267 // consistent with what current_thread_cpu_time() returns
4268 if (os::Linux::supports_fast_thread_cpu_time()) {
4269 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4270 } else {
4271 return slow_thread_cpu_time(thread, true /* user + sys */);
4272 }
4273 }
4274
4275 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4276 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4277 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4278 } else {
4279 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
4280 }
4281 }
4282
4283 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4284 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4285 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4286 } else {
4287 return slow_thread_cpu_time(thread, user_sys_cpu_time);
4288 }
4289 }
4290
4291 //
4292 // -1 on error.
4293 //
4294
4295 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4296 static bool proc_pid_cpu_avail = true;
4297 static bool proc_task_unchecked = true;
4298 static const char *proc_stat_path = "/proc/%d/stat";
4299 pid_t tid = thread->osthread()->thread_id();
4300 int i;
4301 char *s;
4302 char stat[2048];
4303 int statlen;
4304 char proc_name[64];
4305 int count;
4306 long sys_time, user_time;
4307 char string[64];
4308 int idummy;
4309 long ldummy;
4310 FILE *fp;
4311
4312 // We first try accessing /proc/<pid>/cpu since this is faster to
4313 // process. If this file is not present (linux kernels 2.5 and above)
4314 // then we open /proc/<pid>/stat.
4315 if ( proc_pid_cpu_avail ) {
4316 sprintf(proc_name, "/proc/%d/cpu", tid);
4317 fp = fopen(proc_name, "r");
4318 if ( fp != NULL ) {
4319 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
4320 fclose(fp);
4321 if ( count != 3 ) return -1;
4322
4323 if (user_sys_cpu_time) {
4324 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4325 } else {
4326 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4327 }
4328 }
4329 else proc_pid_cpu_avail = false;
4330 }
4331
4332 // The /proc/<tid>/stat aggregates per-process usage on
4333 // new Linux kernels 2.6+ where NPTL is supported.
4334 // The /proc/self/task/<tid>/stat still has the per-thread usage.
4335 // See bug 6328462.
4336 // There can be no directory /proc/self/task on kernels 2.4 with NPTL
4337 // and possibly in some other cases, so we check its availability.
4338 if (proc_task_unchecked && os::Linux::is_NPTL()) {
4339 // This is executed only once
4340 proc_task_unchecked = false;
4341 fp = fopen("/proc/self/task", "r");
4342 if (fp != NULL) {
4343 proc_stat_path = "/proc/self/task/%d/stat";
4344 fclose(fp);
4345 }
4346 }
4347
4348 sprintf(proc_name, proc_stat_path, tid);
4349 fp = fopen(proc_name, "r");
4350 if ( fp == NULL ) return -1;
4351 statlen = fread(stat, 1, 2047, fp);
4352 stat[statlen] = '\0';
4353 fclose(fp);
4354
4355 // Skip pid and the command string. Note that we could be dealing with
4356 // weird command names, e.g. user could decide to rename java launcher
4357 // to "java 1.4.2 :)", then the stat file would look like
4358 // 1234 (java 1.4.2 :)) R ... ...
4359 // We don't really need to know the command string, just find the last
4360 // occurrence of ")" and then start parsing from there. See bug 4726580.
4361 s = strrchr(stat, ')');
4362 i = 0;
4363 if (s == NULL ) return -1;
4364
4365 // Skip blank chars
4366 do s++; while (isspace(*s));
4367
4368 count = sscanf(s,"%*c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
4369 &idummy, &idummy, &idummy, &idummy, &idummy,
4370 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
4371 &user_time, &sys_time);
4372 if ( count != 12 ) return -1;
4373 if (user_sys_cpu_time) {
4374 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4375 } else {
4376 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4377 }
4378 }
4379
4380 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4381 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4382 info_ptr->may_skip_backward = false; // elapsed time not wall time
4383 info_ptr->may_skip_forward = false; // elapsed time not wall time
4384 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4385 }
4386
4387 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4388 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4389 info_ptr->may_skip_backward = false; // elapsed time not wall time
4390 info_ptr->may_skip_forward = false; // elapsed time not wall time
4391 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4392 }
4393
4394 bool os::is_thread_cpu_time_supported() {
4395 return true;
4396 }
4397
4398 // System loadavg support. Returns -1 if load average cannot be obtained.
4399 // Linux doesn't yet have a (official) notion of processor sets,
4400 // so just return the system wide load average.
4401 int os::loadavg(double loadavg[], int nelem) {
4402 return ::getloadavg(loadavg, nelem);
4403 }
4404
4405 void os::pause() {
4406 char filename[MAX_PATH];
4407 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4408 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4409 } else {
4410 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4411 }
4412
4413 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4414 if (fd != -1) {
4415 struct stat buf;
4416 close(fd);
4417 while (::stat(filename, &buf) == 0) {
4418 (void)::poll(NULL, 0, 100);
4419 }
4420 } else {
4421 jio_fprintf(stderr,
4422 "Could not open pause file '%s', continuing immediately.\n", filename);
4423 }
4424 }
4425
4426 extern "C" {
4427
4428 /**
4429 * NOTE: the following code is to keep the green threads code
4430 * in the libjava.so happy. Once the green threads is removed,
4431 * these code will no longer be needed.
4432 */
4433 int
4434 jdk_waitpid(pid_t pid, int* status, int options) {
4435 return waitpid(pid, status, options);
4436 }
4437
4438 int
4439 fork1() {
4440 return fork();
4441 }
4442
4443 int
4444 jdk_sem_init(sem_t *sem, int pshared, unsigned int value) {
4445 return sem_init(sem, pshared, value);
4446 }
4447
4448 int
4449 jdk_sem_post(sem_t *sem) {
4450 return sem_post(sem);
4451 }
4452
4453 int
4454 jdk_sem_wait(sem_t *sem) {
4455 return sem_wait(sem);
4456 }
4457
4458 int
4459 jdk_pthread_sigmask(int how , const sigset_t* newmask, sigset_t* oldmask) {
4460 return pthread_sigmask(how , newmask, oldmask);
4461 }
4462
4463 }
4464
4465 // Refer to the comments in os_solaris.cpp park-unpark.
4466 //
4467 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4468 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4469 // For specifics regarding the bug see GLIBC BUGID 261237 :
4470 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4471 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4472 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4473 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
4474 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4475 // and monitorenter when we're using 1-0 locking. All those operations may result in
4476 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
4477 // of libpthread avoids the problem, but isn't practical.
4478 //
4479 // Possible remedies:
4480 //
4481 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
4482 // This is palliative and probabilistic, however. If the thread is preempted
4483 // between the call to compute_abstime() and pthread_cond_timedwait(), more
4484 // than the minimum period may have passed, and the abstime may be stale (in the
4485 // past) resultin in a hang. Using this technique reduces the odds of a hang
4486 // but the JVM is still vulnerable, particularly on heavily loaded systems.
4487 //
4488 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4489 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
4490 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4491 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
4492 // thread.
4493 //
4494 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
4495 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
4496 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
4497 // This also works well. In fact it avoids kernel-level scalability impediments
4498 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
4499 // timers in a graceful fashion.
4500 //
4501 // 4. When the abstime value is in the past it appears that control returns
4502 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4503 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
4504 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
4505 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
4506 // It may be possible to avoid reinitialization by checking the return
4507 // value from pthread_cond_timedwait(). In addition to reinitializing the
4508 // condvar we must establish the invariant that cond_signal() is only called
4509 // within critical sections protected by the adjunct mutex. This prevents
4510 // cond_signal() from "seeing" a condvar that's in the midst of being
4511 // reinitialized or that is corrupt. Sadly, this invariant obviates the
4512 // desirable signal-after-unlock optimization that avoids futile context switching.
4513 //
4514 // I'm also concerned that some versions of NTPL might allocate an auxilliary
4515 // structure when a condvar is used or initialized. cond_destroy() would
4516 // release the helper structure. Our reinitialize-after-timedwait fix
4517 // put excessive stress on malloc/free and locks protecting the c-heap.
4518 //
4519 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
4520 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4521 // and only enabling the work-around for vulnerable environments.
4522
4523 // utility to compute the abstime argument to timedwait:
4524 // millis is the relative timeout time
4525 // abstime will be the absolute timeout time
4526 // TODO: replace compute_abstime() with unpackTime()
4527
4528 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
4529 if (millis < 0) millis = 0;
4530 struct timeval now;
4531 int status = gettimeofday(&now, NULL);
4532 assert(status == 0, "gettimeofday");
4533 jlong seconds = millis / 1000;
4534 millis %= 1000;
4535 if (seconds > 50000000) { // see man cond_timedwait(3T)
4536 seconds = 50000000;
4537 }
4538 abstime->tv_sec = now.tv_sec + seconds;
4539 long usec = now.tv_usec + millis * 1000;
4540 if (usec >= 1000000) {
4541 abstime->tv_sec += 1;
4542 usec -= 1000000;
4543 }
4544 abstime->tv_nsec = usec * 1000;
4545 return abstime;
4546 }
4547
4548
4549 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
4550 // Conceptually TryPark() should be equivalent to park(0).
4551
4552 int os::PlatformEvent::TryPark() {
4553 for (;;) {
4554 const int v = _Event ;
4555 guarantee ((v == 0) || (v == 1), "invariant") ;
4556 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
4557 }
4558 }
4559
4560 void os::PlatformEvent::park() { // AKA "down()"
4561 // Invariant: Only the thread associated with the Event/PlatformEvent
4562 // may call park().
4563 // TODO: assert that _Assoc != NULL or _Assoc == Self
4564 int v ;
4565 for (;;) {
4566 v = _Event ;
4567 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
4568 }
4569 guarantee (v >= 0, "invariant") ;
4570 if (v == 0) {
4571 // Do this the hard way by blocking ...
4572 int status = pthread_mutex_lock(_mutex);
4573 assert_status(status == 0, status, "mutex_lock");
4574 guarantee (_nParked == 0, "invariant") ;
4575 ++ _nParked ;
4576 while (_Event < 0) {
4577 status = pthread_cond_wait(_cond, _mutex);
4578 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
4579 // Treat this the same as if the wait was interrupted
4580 if (status == ETIME) { status = EINTR; }
4581 assert_status(status == 0 || status == EINTR, status, "cond_wait");
4582 }
4583 -- _nParked ;
4584
4585 // In theory we could move the ST of 0 into _Event past the unlock(),
4586 // but then we'd need a MEMBAR after the ST.
4587 _Event = 0 ;
4588 status = pthread_mutex_unlock(_mutex);
4589 assert_status(status == 0, status, "mutex_unlock");
4590 }
4591 guarantee (_Event >= 0, "invariant") ;
4592 }
4593
4594 int os::PlatformEvent::park(jlong millis) {
4595 guarantee (_nParked == 0, "invariant") ;
4596
4597 int v ;
4598 for (;;) {
4599 v = _Event ;
4600 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
4601 }
4602 guarantee (v >= 0, "invariant") ;
4603 if (v != 0) return OS_OK ;
4604
4605 // We do this the hard way, by blocking the thread.
4606 // Consider enforcing a minimum timeout value.
4607 struct timespec abst;
4608 compute_abstime(&abst, millis);
4609
4610 int ret = OS_TIMEOUT;
4611 int status = pthread_mutex_lock(_mutex);
4612 assert_status(status == 0, status, "mutex_lock");
4613 guarantee (_nParked == 0, "invariant") ;
4614 ++_nParked ;
4615
4616 // Object.wait(timo) will return because of
4617 // (a) notification
4618 // (b) timeout
4619 // (c) thread.interrupt
4620 //
4621 // Thread.interrupt and object.notify{All} both call Event::set.
4622 // That is, we treat thread.interrupt as a special case of notification.
4623 // The underlying Solaris implementation, cond_timedwait, admits
4624 // spurious/premature wakeups, but the JLS/JVM spec prevents the
4625 // JVM from making those visible to Java code. As such, we must
4626 // filter out spurious wakeups. We assume all ETIME returns are valid.
4627 //
4628 // TODO: properly differentiate simultaneous notify+interrupt.
4629 // In that case, we should propagate the notify to another waiter.
4630
4631 while (_Event < 0) {
4632 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
4633 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
4634 pthread_cond_destroy (_cond);
4635 pthread_cond_init (_cond, NULL) ;
4636 }
4637 assert_status(status == 0 || status == EINTR ||
4638 status == ETIME || status == ETIMEDOUT,
4639 status, "cond_timedwait");
4640 if (!FilterSpuriousWakeups) break ; // previous semantics
4641 if (status == ETIME || status == ETIMEDOUT) break ;
4642 // We consume and ignore EINTR and spurious wakeups.
4643 }
4644 --_nParked ;
4645 if (_Event >= 0) {
4646 ret = OS_OK;
4647 }
4648 _Event = 0 ;
4649 status = pthread_mutex_unlock(_mutex);
4650 assert_status(status == 0, status, "mutex_unlock");
4651 assert (_nParked == 0, "invariant") ;
4652 return ret;
4653 }
4654
4655 void os::PlatformEvent::unpark() {
4656 int v, AnyWaiters ;
4657 for (;;) {
4658 v = _Event ;
4659 if (v > 0) {
4660 // The LD of _Event could have reordered or be satisfied
4661 // by a read-aside from this processor's write buffer.
4662 // To avoid problems execute a barrier and then
4663 // ratify the value.
4664 OrderAccess::fence() ;
4665 if (_Event == v) return ;
4666 continue ;
4667 }
4668 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
4669 }
4670 if (v < 0) {
4671 // Wait for the thread associated with the event to vacate
4672 int status = pthread_mutex_lock(_mutex);
4673 assert_status(status == 0, status, "mutex_lock");
4674 AnyWaiters = _nParked ;
4675 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ;
4676 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
4677 AnyWaiters = 0 ;
4678 pthread_cond_signal (_cond);
4679 }
4680 status = pthread_mutex_unlock(_mutex);
4681 assert_status(status == 0, status, "mutex_unlock");
4682 if (AnyWaiters != 0) {
4683 status = pthread_cond_signal(_cond);
4684 assert_status(status == 0, status, "cond_signal");
4685 }
4686 }
4687
4688 // Note that we signal() _after dropping the lock for "immortal" Events.
4689 // This is safe and avoids a common class of futile wakeups. In rare
4690 // circumstances this can cause a thread to return prematurely from
4691 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
4692 // simply re-test the condition and re-park itself.
4693 }
4694
4695
4696 // JSR166
4697 // -------------------------------------------------------
4698
4699 /*
4700 * The solaris and linux implementations of park/unpark are fairly
4701 * conservative for now, but can be improved. They currently use a
4702 * mutex/condvar pair, plus a a count.
4703 * Park decrements count if > 0, else does a condvar wait. Unpark
4704 * sets count to 1 and signals condvar. Only one thread ever waits
4705 * on the condvar. Contention seen when trying to park implies that someone
4706 * is unparking you, so don't wait. And spurious returns are fine, so there
4707 * is no need to track notifications.
4708 */
4709
4710
4711 #define NANOSECS_PER_SEC 1000000000
4712 #define NANOSECS_PER_MILLISEC 1000000
4713 #define MAX_SECS 100000000
4714 /*
4715 * This code is common to linux and solaris and will be moved to a
4716 * common place in dolphin.
4717 *
4718 * The passed in time value is either a relative time in nanoseconds
4719 * or an absolute time in milliseconds. Either way it has to be unpacked
4720 * into suitable seconds and nanoseconds components and stored in the
4721 * given timespec structure.
4722 * Given time is a 64-bit value and the time_t used in the timespec is only
4723 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
4724 * overflow if times way in the future are given. Further on Solaris versions
4725 * prior to 10 there is a restriction (see cond_timedwait) that the specified
4726 * number of seconds, in abstime, is less than current_time + 100,000,000.
4727 * As it will be 28 years before "now + 100000000" will overflow we can
4728 * ignore overflow and just impose a hard-limit on seconds using the value
4729 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
4730 * years from "now".
4731 */
4732
4733 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
4734 assert (time > 0, "convertTime");
4735
4736 struct timeval now;
4737 int status = gettimeofday(&now, NULL);
4738 assert(status == 0, "gettimeofday");
4739
4740 time_t max_secs = now.tv_sec + MAX_SECS;
4741
4742 if (isAbsolute) {
4743 jlong secs = time / 1000;
4744 if (secs > max_secs) {
4745 absTime->tv_sec = max_secs;
4746 }
4747 else {
4748 absTime->tv_sec = secs;
4749 }
4750 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
4751 }
4752 else {
4753 jlong secs = time / NANOSECS_PER_SEC;
4754 if (secs >= MAX_SECS) {
4755 absTime->tv_sec = max_secs;
4756 absTime->tv_nsec = 0;
4757 }
4758 else {
4759 absTime->tv_sec = now.tv_sec + secs;
4760 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
4761 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
4762 absTime->tv_nsec -= NANOSECS_PER_SEC;
4763 ++absTime->tv_sec; // note: this must be <= max_secs
4764 }
4765 }
4766 }
4767 assert(absTime->tv_sec >= 0, "tv_sec < 0");
4768 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
4769 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
4770 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
4771 }
4772
4773 void Parker::park(bool isAbsolute, jlong time) {
4774 // Optional fast-path check:
4775 // Return immediately if a permit is available.
4776 if (_counter > 0) {
4777 _counter = 0 ;
4778 OrderAccess::fence();
4779 return ;
4780 }
4781
4782 Thread* thread = Thread::current();
4783 assert(thread->is_Java_thread(), "Must be JavaThread");
4784 JavaThread *jt = (JavaThread *)thread;
4785
4786 // Optional optimization -- avoid state transitions if there's an interrupt pending.
4787 // Check interrupt before trying to wait
4788 if (Thread::is_interrupted(thread, false)) {
4789 return;
4790 }
4791
4792 // Next, demultiplex/decode time arguments
4793 timespec absTime;
4794 if (time < 0) { // don't wait at all
4795 return;
4796 }
4797 if (time > 0) {
4798 unpackTime(&absTime, isAbsolute, time);
4799 }
4800
4801
4802 // Enter safepoint region
4803 // Beware of deadlocks such as 6317397.
4804 // The per-thread Parker:: mutex is a classic leaf-lock.
4805 // In particular a thread must never block on the Threads_lock while
4806 // holding the Parker:: mutex. If safepoints are pending both the
4807 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
4808 ThreadBlockInVM tbivm(jt);
4809
4810 // Don't wait if cannot get lock since interference arises from
4811 // unblocking. Also. check interrupt before trying wait
4812 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
4813 return;
4814 }
4815
4816 int status ;
4817 if (_counter > 0) { // no wait needed
4818 _counter = 0;
4819 status = pthread_mutex_unlock(_mutex);
4820 assert (status == 0, "invariant") ;
4821 OrderAccess::fence();
4822 return;
4823 }
4824
4825 #ifdef ASSERT
4826 // Don't catch signals while blocked; let the running threads have the signals.
4827 // (This allows a debugger to break into the running thread.)
4828 sigset_t oldsigs;
4829 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
4830 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
4831 #endif
4832
4833 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
4834 jt->set_suspend_equivalent();
4835 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
4836
4837 if (time == 0) {
4838 status = pthread_cond_wait (_cond, _mutex) ;
4839 } else {
4840 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
4841 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
4842 pthread_cond_destroy (_cond) ;
4843 pthread_cond_init (_cond, NULL);
4844 }
4845 }
4846 assert_status(status == 0 || status == EINTR ||
4847 status == ETIME || status == ETIMEDOUT,
4848 status, "cond_timedwait");
4849
4850 #ifdef ASSERT
4851 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
4852 #endif
4853
4854 _counter = 0 ;
4855 status = pthread_mutex_unlock(_mutex) ;
4856 assert_status(status == 0, status, "invariant") ;
4857 // If externally suspended while waiting, re-suspend
4858 if (jt->handle_special_suspend_equivalent_condition()) {
4859 jt->java_suspend_self();
4860 }
4861
4862 OrderAccess::fence();
4863 }
4864
4865 void Parker::unpark() {
4866 int s, status ;
4867 status = pthread_mutex_lock(_mutex);
4868 assert (status == 0, "invariant") ;
4869 s = _counter;
4870 _counter = 1;
4871 if (s < 1) {
4872 if (WorkAroundNPTLTimedWaitHang) {
4873 status = pthread_cond_signal (_cond) ;
4874 assert (status == 0, "invariant") ;
4875 status = pthread_mutex_unlock(_mutex);
4876 assert (status == 0, "invariant") ;
4877 } else {
4878 status = pthread_mutex_unlock(_mutex);
4879 assert (status == 0, "invariant") ;
4880 status = pthread_cond_signal (_cond) ;
4881 assert (status == 0, "invariant") ;
4882 }
4883 } else {
4884 pthread_mutex_unlock(_mutex);
4885 assert (status == 0, "invariant") ;
4886 }
4887 }
4888
4889
4890 extern char** environ;
4891
4892 #ifndef __NR_fork
4893 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
4894 #endif
4895
4896 #ifndef __NR_execve
4897 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
4898 #endif
4899
4900 // Run the specified command in a separate process. Return its exit value,
4901 // or -1 on failure (e.g. can't fork a new process).
4902 // Unlike system(), this function can be called from signal handler. It
4903 // doesn't block SIGINT et al.
4904 int os::fork_and_exec(char* cmd) {
4905 const char * argv[4] = {"sh", "-c", cmd, NULL};
4906
4907 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
4908 // pthread_atfork handlers and reset pthread library. All we need is a
4909 // separate process to execve. Make a direct syscall to fork process.
4910 // On IA64 there's no fork syscall, we have to use fork() and hope for
4911 // the best...
4912 pid_t pid = NOT_IA64(syscall(__NR_fork);)
4913 IA64_ONLY(fork();)
4914
4915 if (pid < 0) {
4916 // fork failed
4917 return -1;
4918
4919 } else if (pid == 0) {
4920 // child process
4921
4922 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
4923 // first to kill every thread on the thread list. Because this list is
4924 // not reset by fork() (see notes above), execve() will instead kill
4925 // every thread in the parent process. We know this is the only thread
4926 // in the new process, so make a system call directly.
4927 // IA64 should use normal execve() from glibc to match the glibc fork()
4928 // above.
4929 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
4930 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
4931
4932 // execve failed
4933 _exit(-1);
4934
4935 } else {
4936 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
4937 // care about the actual exit code, for now.
4938
4939 int status;
4940
4941 // Wait for the child process to exit. This returns immediately if
4942 // the child has already exited. */
4943 while (waitpid(pid, &status, 0) < 0) {
4944 switch (errno) {
4945 case ECHILD: return 0;
4946 case EINTR: break;
4947 default: return -1;
4948 }
4949 }
4950
4951 if (WIFEXITED(status)) {
4952 // The child exited normally; get its exit code.
4953 return WEXITSTATUS(status);
4954 } else if (WIFSIGNALED(status)) {
4955 // The child exited because of a signal
4956 // The best value to return is 0x80 + signal number,
4957 // because that is what all Unix shells do, and because
4958 // it allows callers to distinguish between process exit and
4959 // process death by signal.
4960 return 0x80 + WTERMSIG(status);
4961 } else {
4962 // Unknown exit code; pass it through
4963 return status;
4964 }
4965 }
4966 }