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