1 /*
   2  * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 // no precompiled headers
  26 #include "classfile/classLoader.hpp"
  27 #include "classfile/systemDictionary.hpp"
  28 #include "classfile/vmSymbols.hpp"
  29 #include "code/icBuffer.hpp"
  30 #include "code/vtableStubs.hpp"
  31 #include "compiler/compileBroker.hpp"
  32 #include "compiler/disassembler.hpp"
  33 #include "interpreter/interpreter.hpp"
  34 #include "jvm_bsd.h"
  35 #include "memory/allocation.inline.hpp"
  36 #include "memory/filemap.hpp"
  37 #include "mutex_bsd.inline.hpp"
  38 #include "oops/oop.inline.hpp"
  39 #include "os_bsd.inline.hpp"
  40 #include "os_share_bsd.hpp"
  41 #include "prims/jniFastGetField.hpp"
  42 #include "prims/jvm.h"
  43 #include "prims/jvm_misc.hpp"
  44 #include "runtime/arguments.hpp"
  45 #include "runtime/atomic.inline.hpp"
  46 #include "runtime/extendedPC.hpp"
  47 #include "runtime/globals.hpp"
  48 #include "runtime/interfaceSupport.hpp"
  49 #include "runtime/java.hpp"
  50 #include "runtime/javaCalls.hpp"
  51 #include "runtime/mutexLocker.hpp"
  52 #include "runtime/objectMonitor.hpp"
  53 #include "runtime/orderAccess.inline.hpp"
  54 #include "runtime/osThread.hpp"
  55 #include "runtime/perfMemory.hpp"
  56 #include "runtime/sharedRuntime.hpp"
  57 #include "runtime/statSampler.hpp"
  58 #include "runtime/stubRoutines.hpp"
  59 #include "runtime/thread.inline.hpp"
  60 #include "runtime/threadCritical.hpp"
  61 #include "runtime/timer.hpp"
  62 #include "semaphore_bsd.hpp"
  63 #include "services/attachListener.hpp"
  64 #include "services/memTracker.hpp"
  65 #include "services/runtimeService.hpp"
  66 #include "utilities/decoder.hpp"
  67 #include "utilities/defaultStream.hpp"
  68 #include "utilities/events.hpp"
  69 #include "utilities/growableArray.hpp"
  70 #include "utilities/vmError.hpp"
  71 
  72 // put OS-includes here
  73 # include <sys/types.h>
  74 # include <sys/mman.h>
  75 # include <sys/stat.h>
  76 # include <sys/select.h>
  77 # include <pthread.h>
  78 # include <signal.h>
  79 # include <errno.h>
  80 # include <dlfcn.h>
  81 # include <stdio.h>
  82 # include <unistd.h>
  83 # include <sys/resource.h>
  84 # include <pthread.h>
  85 # include <sys/stat.h>
  86 # include <sys/time.h>
  87 # include <sys/times.h>
  88 # include <sys/utsname.h>
  89 # include <sys/socket.h>
  90 # include <sys/wait.h>
  91 # include <time.h>
  92 # include <pwd.h>
  93 # include <poll.h>
  94 # include <semaphore.h>
  95 # include <fcntl.h>
  96 # include <string.h>
  97 # include <sys/param.h>
  98 # include <sys/sysctl.h>
  99 # include <sys/ipc.h>
 100 # include <sys/shm.h>
 101 #ifndef __APPLE__
 102 # include <link.h>
 103 #endif
 104 # include <stdint.h>
 105 # include <inttypes.h>
 106 # include <sys/ioctl.h>
 107 # include <sys/syscall.h>
 108 
 109 #if defined(__FreeBSD__) || defined(__NetBSD__)
 110   #include <elf.h>
 111 #endif
 112 
 113 #ifdef __APPLE__
 114   #include <mach/mach.h> // semaphore_* API
 115   #include <mach-o/dyld.h>
 116   #include <sys/proc_info.h>
 117   #include <objc/objc-auto.h>
 118 #endif
 119 
 120 #ifndef MAP_ANONYMOUS
 121   #define MAP_ANONYMOUS MAP_ANON
 122 #endif
 123 
 124 #define MAX_PATH    (2 * K)
 125 
 126 // for timer info max values which include all bits
 127 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
 128 
 129 #define LARGEPAGES_BIT (1 << 6)
 130 
 131 ////////////////////////////////////////////////////////////////////////////////
 132 // global variables
 133 julong os::Bsd::_physical_memory = 0;
 134 
 135 #ifdef __APPLE__
 136 mach_timebase_info_data_t os::Bsd::_timebase_info = {0, 0};
 137 volatile uint64_t         os::Bsd::_max_abstime   = 0;
 138 #else
 139 int (*os::Bsd::_clock_gettime)(clockid_t, struct timespec *) = NULL;
 140 #endif
 141 pthread_t os::Bsd::_main_thread;
 142 int os::Bsd::_page_size = -1;
 143 
 144 static jlong initial_time_count=0;
 145 
 146 static int clock_tics_per_sec = 100;
 147 
 148 // For diagnostics to print a message once. see run_periodic_checks
 149 static sigset_t check_signal_done;
 150 static bool check_signals = true;
 151 
 152 static pid_t _initial_pid = 0;
 153 
 154 // Signal number used to suspend/resume a thread
 155 
 156 // do not use any signal number less than SIGSEGV, see 4355769
 157 static int SR_signum = SIGUSR2;
 158 sigset_t SR_sigset;
 159 
 160 
 161 ////////////////////////////////////////////////////////////////////////////////
 162 // utility functions
 163 
 164 static int SR_initialize();
 165 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
 166 
 167 julong os::available_memory() {
 168   return Bsd::available_memory();
 169 }
 170 
 171 // available here means free
 172 julong os::Bsd::available_memory() {
 173   uint64_t available = physical_memory() >> 2;
 174 #ifdef __APPLE__
 175   mach_msg_type_number_t count = HOST_VM_INFO64_COUNT;
 176   vm_statistics64_data_t vmstat;
 177   kern_return_t kerr = host_statistics64(mach_host_self(), HOST_VM_INFO64,
 178                                          (host_info64_t)&vmstat, &count);
 179   assert(kerr == KERN_SUCCESS,
 180          "host_statistics64 failed - check mach_host_self() and count");
 181   if (kerr == KERN_SUCCESS) {
 182     available = vmstat.free_count * os::vm_page_size();
 183   }
 184 #endif
 185   return available;
 186 }
 187 
 188 julong os::physical_memory() {
 189   return Bsd::physical_memory();
 190 }
 191 
 192 // Return true if user is running as root.
 193 
 194 bool os::have_special_privileges() {
 195   static bool init = false;
 196   static bool privileges = false;
 197   if (!init) {
 198     privileges = (getuid() != geteuid()) || (getgid() != getegid());
 199     init = true;
 200   }
 201   return privileges;
 202 }
 203 
 204 
 205 
 206 // Cpu architecture string
 207 #if   defined(ZERO)
 208 static char cpu_arch[] = ZERO_LIBARCH;
 209 #elif defined(IA64)
 210 static char cpu_arch[] = "ia64";
 211 #elif defined(IA32)
 212 static char cpu_arch[] = "i386";
 213 #elif defined(AMD64)
 214 static char cpu_arch[] = "amd64";
 215 #elif defined(ARM)
 216 static char cpu_arch[] = "arm";
 217 #elif defined(PPC32)
 218 static char cpu_arch[] = "ppc";
 219 #elif defined(SPARC)
 220   #ifdef _LP64
 221 static char cpu_arch[] = "sparcv9";
 222   #else
 223 static char cpu_arch[] = "sparc";
 224   #endif
 225 #else
 226   #error Add appropriate cpu_arch setting
 227 #endif
 228 
 229 // Compiler variant
 230 #ifdef COMPILER2
 231   #define COMPILER_VARIANT "server"
 232 #else
 233   #define COMPILER_VARIANT "client"
 234 #endif
 235 
 236 
 237 void os::Bsd::initialize_system_info() {
 238   int mib[2];
 239   size_t len;
 240   int cpu_val;
 241   julong mem_val;
 242 
 243   // get processors count via hw.ncpus sysctl
 244   mib[0] = CTL_HW;
 245   mib[1] = HW_NCPU;
 246   len = sizeof(cpu_val);
 247   if (sysctl(mib, 2, &cpu_val, &len, NULL, 0) != -1 && cpu_val >= 1) {
 248     assert(len == sizeof(cpu_val), "unexpected data size");
 249     set_processor_count(cpu_val);
 250   } else {
 251     set_processor_count(1);   // fallback
 252   }
 253 
 254   // get physical memory via hw.memsize sysctl (hw.memsize is used
 255   // since it returns a 64 bit value)
 256   mib[0] = CTL_HW;
 257 
 258 #if defined (HW_MEMSIZE) // Apple
 259   mib[1] = HW_MEMSIZE;
 260 #elif defined(HW_PHYSMEM) // Most of BSD
 261   mib[1] = HW_PHYSMEM;
 262 #elif defined(HW_REALMEM) // Old FreeBSD
 263   mib[1] = HW_REALMEM;
 264 #else
 265   #error No ways to get physmem
 266 #endif
 267 
 268   len = sizeof(mem_val);
 269   if (sysctl(mib, 2, &mem_val, &len, NULL, 0) != -1) {
 270     assert(len == sizeof(mem_val), "unexpected data size");
 271     _physical_memory = mem_val;
 272   } else {
 273     _physical_memory = 256 * 1024 * 1024;       // fallback (XXXBSD?)
 274   }
 275 
 276 #ifdef __OpenBSD__
 277   {
 278     // limit _physical_memory memory view on OpenBSD since
 279     // datasize rlimit restricts us anyway.
 280     struct rlimit limits;
 281     getrlimit(RLIMIT_DATA, &limits);
 282     _physical_memory = MIN2(_physical_memory, (julong)limits.rlim_cur);
 283   }
 284 #endif
 285 }
 286 
 287 #ifdef __APPLE__
 288 static const char *get_home() {
 289   const char *home_dir = ::getenv("HOME");
 290   if ((home_dir == NULL) || (*home_dir == '\0')) {
 291     struct passwd *passwd_info = getpwuid(geteuid());
 292     if (passwd_info != NULL) {
 293       home_dir = passwd_info->pw_dir;
 294     }
 295   }
 296 
 297   return home_dir;
 298 }
 299 #endif
 300 
 301 void os::init_system_properties_values() {
 302   // The next steps are taken in the product version:
 303   //
 304   // Obtain the JAVA_HOME value from the location of libjvm.so.
 305   // This library should be located at:
 306   // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so.
 307   //
 308   // If "/jre/lib/" appears at the right place in the path, then we
 309   // assume libjvm.so is installed in a JDK and we use this path.
 310   //
 311   // Otherwise exit with message: "Could not create the Java virtual machine."
 312   //
 313   // The following extra steps are taken in the debugging version:
 314   //
 315   // If "/jre/lib/" does NOT appear at the right place in the path
 316   // instead of exit check for $JAVA_HOME environment variable.
 317   //
 318   // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
 319   // then we append a fake suffix "hotspot/libjvm.so" to this path so
 320   // it looks like libjvm.so is installed there
 321   // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
 322   //
 323   // Otherwise exit.
 324   //
 325   // Important note: if the location of libjvm.so changes this
 326   // code needs to be changed accordingly.
 327 
 328   // See ld(1):
 329   //      The linker uses the following search paths to locate required
 330   //      shared libraries:
 331   //        1: ...
 332   //        ...
 333   //        7: The default directories, normally /lib and /usr/lib.
 334 #ifndef DEFAULT_LIBPATH
 335   #define DEFAULT_LIBPATH "/lib:/usr/lib"
 336 #endif
 337 
 338 // Base path of extensions installed on the system.
 339 #define SYS_EXT_DIR     "/usr/java/packages"
 340 #define EXTENSIONS_DIR  "/lib/ext"
 341 
 342 #ifndef __APPLE__
 343 
 344   // Buffer that fits several sprintfs.
 345   // Note that the space for the colon and the trailing null are provided
 346   // by the nulls included by the sizeof operator.
 347   const size_t bufsize =
 348     MAX2((size_t)MAXPATHLEN,  // For dll_dir & friends.
 349          (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
 350   char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
 351 
 352   // sysclasspath, java_home, dll_dir
 353   {
 354     char *pslash;
 355     os::jvm_path(buf, bufsize);
 356 
 357     // Found the full path to libjvm.so.
 358     // Now cut the path to <java_home>/jre if we can.
 359     *(strrchr(buf, '/')) = '\0'; // Get rid of /libjvm.so.
 360     pslash = strrchr(buf, '/');
 361     if (pslash != NULL) {
 362       *pslash = '\0';            // Get rid of /{client|server|hotspot}.
 363     }
 364     Arguments::set_dll_dir(buf);
 365 
 366     if (pslash != NULL) {
 367       pslash = strrchr(buf, '/');
 368       if (pslash != NULL) {
 369         *pslash = '\0';          // Get rid of /<arch>.
 370         pslash = strrchr(buf, '/');
 371         if (pslash != NULL) {
 372           *pslash = '\0';        // Get rid of /lib.
 373         }
 374       }
 375     }
 376     Arguments::set_java_home(buf);
 377     set_boot_path('/', ':');
 378   }
 379 
 380   // Where to look for native libraries.
 381   //
 382   // Note: Due to a legacy implementation, most of the library path
 383   // is set in the launcher. This was to accomodate linking restrictions
 384   // on legacy Bsd implementations (which are no longer supported).
 385   // Eventually, all the library path setting will be done here.
 386   //
 387   // However, to prevent the proliferation of improperly built native
 388   // libraries, the new path component /usr/java/packages is added here.
 389   // Eventually, all the library path setting will be done here.
 390   {
 391     // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
 392     // should always exist (until the legacy problem cited above is
 393     // addressed).
 394     const char *v = ::getenv("LD_LIBRARY_PATH");
 395     const char *v_colon = ":";
 396     if (v == NULL) { v = ""; v_colon = ""; }
 397     // That's +1 for the colon and +1 for the trailing '\0'.
 398     char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
 399                                                      strlen(v) + 1 +
 400                                                      sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1,
 401                                                      mtInternal);
 402     sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch);
 403     Arguments::set_library_path(ld_library_path);
 404     FREE_C_HEAP_ARRAY(char, ld_library_path);
 405   }
 406 
 407   // Extensions directories.
 408   sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
 409   Arguments::set_ext_dirs(buf);
 410 
 411   FREE_C_HEAP_ARRAY(char, buf);
 412 
 413 #else // __APPLE__
 414 
 415   #define SYS_EXTENSIONS_DIR   "/Library/Java/Extensions"
 416   #define SYS_EXTENSIONS_DIRS  SYS_EXTENSIONS_DIR ":/Network" SYS_EXTENSIONS_DIR ":/System" SYS_EXTENSIONS_DIR ":/usr/lib/java"
 417 
 418   const char *user_home_dir = get_home();
 419   // The null in SYS_EXTENSIONS_DIRS counts for the size of the colon after user_home_dir.
 420   size_t system_ext_size = strlen(user_home_dir) + sizeof(SYS_EXTENSIONS_DIR) +
 421     sizeof(SYS_EXTENSIONS_DIRS);
 422 
 423   // Buffer that fits several sprintfs.
 424   // Note that the space for the colon and the trailing null are provided
 425   // by the nulls included by the sizeof operator.
 426   const size_t bufsize =
 427     MAX2((size_t)MAXPATHLEN,  // for dll_dir & friends.
 428          (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + system_ext_size); // extensions dir
 429   char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
 430 
 431   // sysclasspath, java_home, dll_dir
 432   {
 433     char *pslash;
 434     os::jvm_path(buf, bufsize);
 435 
 436     // Found the full path to libjvm.so.
 437     // Now cut the path to <java_home>/jre if we can.
 438     *(strrchr(buf, '/')) = '\0'; // Get rid of /libjvm.so.
 439     pslash = strrchr(buf, '/');
 440     if (pslash != NULL) {
 441       *pslash = '\0';            // Get rid of /{client|server|hotspot}.
 442     }
 443 #ifdef STATIC_BUILD
 444     strcat(buf, "/lib");
 445 #endif
 446 
 447     Arguments::set_dll_dir(buf);
 448 
 449     if (pslash != NULL) {
 450       pslash = strrchr(buf, '/');
 451       if (pslash != NULL) {
 452         *pslash = '\0';          // Get rid of /lib.
 453       }
 454     }
 455     Arguments::set_java_home(buf);
 456     set_boot_path('/', ':');
 457   }
 458 
 459   // Where to look for native libraries.
 460   //
 461   // Note: Due to a legacy implementation, most of the library path
 462   // is set in the launcher. This was to accomodate linking restrictions
 463   // on legacy Bsd implementations (which are no longer supported).
 464   // Eventually, all the library path setting will be done here.
 465   //
 466   // However, to prevent the proliferation of improperly built native
 467   // libraries, the new path component /usr/java/packages is added here.
 468   // Eventually, all the library path setting will be done here.
 469   {
 470     // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
 471     // should always exist (until the legacy problem cited above is
 472     // addressed).
 473     // Prepend the default path with the JAVA_LIBRARY_PATH so that the app launcher code
 474     // can specify a directory inside an app wrapper
 475     const char *l = ::getenv("JAVA_LIBRARY_PATH");
 476     const char *l_colon = ":";
 477     if (l == NULL) { l = ""; l_colon = ""; }
 478 
 479     const char *v = ::getenv("DYLD_LIBRARY_PATH");
 480     const char *v_colon = ":";
 481     if (v == NULL) { v = ""; v_colon = ""; }
 482 
 483     // Apple's Java6 has "." at the beginning of java.library.path.
 484     // OpenJDK on Windows has "." at the end of java.library.path.
 485     // OpenJDK on Linux and Solaris don't have "." in java.library.path
 486     // at all. To ease the transition from Apple's Java6 to OpenJDK7,
 487     // "." is appended to the end of java.library.path. Yes, this
 488     // could cause a change in behavior, but Apple's Java6 behavior
 489     // can be achieved by putting "." at the beginning of the
 490     // JAVA_LIBRARY_PATH environment variable.
 491     char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
 492                                                      strlen(v) + 1 + strlen(l) + 1 +
 493                                                      system_ext_size + 3,
 494                                                      mtInternal);
 495     sprintf(ld_library_path, "%s%s%s%s%s" SYS_EXTENSIONS_DIR ":" SYS_EXTENSIONS_DIRS ":.",
 496             v, v_colon, l, l_colon, user_home_dir);
 497     Arguments::set_library_path(ld_library_path);
 498     FREE_C_HEAP_ARRAY(char, ld_library_path);
 499   }
 500 
 501   // Extensions directories.
 502   //
 503   // Note that the space for the colon and the trailing null are provided
 504   // by the nulls included by the sizeof operator (so actually one byte more
 505   // than necessary is allocated).
 506   sprintf(buf, "%s" SYS_EXTENSIONS_DIR ":%s" EXTENSIONS_DIR ":" SYS_EXTENSIONS_DIRS,
 507           user_home_dir, Arguments::get_java_home());
 508   Arguments::set_ext_dirs(buf);
 509 
 510   FREE_C_HEAP_ARRAY(char, buf);
 511 
 512 #undef SYS_EXTENSIONS_DIR
 513 #undef SYS_EXTENSIONS_DIRS
 514 
 515 #endif // __APPLE__
 516 
 517 #undef SYS_EXT_DIR
 518 #undef EXTENSIONS_DIR
 519 }
 520 
 521 ////////////////////////////////////////////////////////////////////////////////
 522 // breakpoint support
 523 
 524 void os::breakpoint() {
 525   BREAKPOINT;
 526 }
 527 
 528 extern "C" void breakpoint() {
 529   // use debugger to set breakpoint here
 530 }
 531 
 532 ////////////////////////////////////////////////////////////////////////////////
 533 // signal support
 534 
 535 debug_only(static bool signal_sets_initialized = false);
 536 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
 537 
 538 bool os::Bsd::is_sig_ignored(int sig) {
 539   struct sigaction oact;
 540   sigaction(sig, (struct sigaction*)NULL, &oact);
 541   void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*,  oact.sa_sigaction)
 542                                  : CAST_FROM_FN_PTR(void*,  oact.sa_handler);
 543   if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) {
 544     return true;
 545   } else {
 546     return false;
 547   }
 548 }
 549 
 550 void os::Bsd::signal_sets_init() {
 551   // Should also have an assertion stating we are still single-threaded.
 552   assert(!signal_sets_initialized, "Already initialized");
 553   // Fill in signals that are necessarily unblocked for all threads in
 554   // the VM. Currently, we unblock the following signals:
 555   // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
 556   //                         by -Xrs (=ReduceSignalUsage));
 557   // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
 558   // other threads. The "ReduceSignalUsage" boolean tells us not to alter
 559   // the dispositions or masks wrt these signals.
 560   // Programs embedding the VM that want to use the above signals for their
 561   // own purposes must, at this time, use the "-Xrs" option to prevent
 562   // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
 563   // (See bug 4345157, and other related bugs).
 564   // In reality, though, unblocking these signals is really a nop, since
 565   // these signals are not blocked by default.
 566   sigemptyset(&unblocked_sigs);
 567   sigemptyset(&allowdebug_blocked_sigs);
 568   sigaddset(&unblocked_sigs, SIGILL);
 569   sigaddset(&unblocked_sigs, SIGSEGV);
 570   sigaddset(&unblocked_sigs, SIGBUS);
 571   sigaddset(&unblocked_sigs, SIGFPE);
 572   sigaddset(&unblocked_sigs, SR_signum);
 573 
 574   if (!ReduceSignalUsage) {
 575     if (!os::Bsd::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
 576       sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
 577       sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
 578     }
 579     if (!os::Bsd::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
 580       sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
 581       sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
 582     }
 583     if (!os::Bsd::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
 584       sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
 585       sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
 586     }
 587   }
 588   // Fill in signals that are blocked by all but the VM thread.
 589   sigemptyset(&vm_sigs);
 590   if (!ReduceSignalUsage) {
 591     sigaddset(&vm_sigs, BREAK_SIGNAL);
 592   }
 593   debug_only(signal_sets_initialized = true);
 594 
 595 }
 596 
 597 // These are signals that are unblocked while a thread is running Java.
 598 // (For some reason, they get blocked by default.)
 599 sigset_t* os::Bsd::unblocked_signals() {
 600   assert(signal_sets_initialized, "Not initialized");
 601   return &unblocked_sigs;
 602 }
 603 
 604 // These are the signals that are blocked while a (non-VM) thread is
 605 // running Java. Only the VM thread handles these signals.
 606 sigset_t* os::Bsd::vm_signals() {
 607   assert(signal_sets_initialized, "Not initialized");
 608   return &vm_sigs;
 609 }
 610 
 611 // These are signals that are blocked during cond_wait to allow debugger in
 612 sigset_t* os::Bsd::allowdebug_blocked_signals() {
 613   assert(signal_sets_initialized, "Not initialized");
 614   return &allowdebug_blocked_sigs;
 615 }
 616 
 617 void os::Bsd::hotspot_sigmask(Thread* thread) {
 618 
 619   //Save caller's signal mask before setting VM signal mask
 620   sigset_t caller_sigmask;
 621   pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
 622 
 623   OSThread* osthread = thread->osthread();
 624   osthread->set_caller_sigmask(caller_sigmask);
 625 
 626   pthread_sigmask(SIG_UNBLOCK, os::Bsd::unblocked_signals(), NULL);
 627 
 628   if (!ReduceSignalUsage) {
 629     if (thread->is_VM_thread()) {
 630       // Only the VM thread handles BREAK_SIGNAL ...
 631       pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
 632     } else {
 633       // ... all other threads block BREAK_SIGNAL
 634       pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
 635     }
 636   }
 637 }
 638 
 639 
 640 //////////////////////////////////////////////////////////////////////////////
 641 // create new thread
 642 
 643 #ifdef __APPLE__
 644 // library handle for calling objc_registerThreadWithCollector()
 645 // without static linking to the libobjc library
 646   #define OBJC_LIB "/usr/lib/libobjc.dylib"
 647   #define OBJC_GCREGISTER "objc_registerThreadWithCollector"
 648 typedef void (*objc_registerThreadWithCollector_t)();
 649 extern "C" objc_registerThreadWithCollector_t objc_registerThreadWithCollectorFunction;
 650 objc_registerThreadWithCollector_t objc_registerThreadWithCollectorFunction = NULL;
 651 #endif
 652 
 653 #ifdef __APPLE__
 654 static uint64_t locate_unique_thread_id(mach_port_t mach_thread_port) {
 655   // Additional thread_id used to correlate threads in SA
 656   thread_identifier_info_data_t     m_ident_info;
 657   mach_msg_type_number_t            count = THREAD_IDENTIFIER_INFO_COUNT;
 658 
 659   thread_info(mach_thread_port, THREAD_IDENTIFIER_INFO,
 660               (thread_info_t) &m_ident_info, &count);
 661 
 662   return m_ident_info.thread_id;
 663 }
 664 #endif
 665 
 666 // Thread start routine for all newly created threads
 667 static void *java_start(Thread *thread) {
 668   // Try to randomize the cache line index of hot stack frames.
 669   // This helps when threads of the same stack traces evict each other's
 670   // cache lines. The threads can be either from the same JVM instance, or
 671   // from different JVM instances. The benefit is especially true for
 672   // processors with hyperthreading technology.
 673   static int counter = 0;
 674   int pid = os::current_process_id();
 675   alloca(((pid ^ counter++) & 7) * 128);
 676 
 677   ThreadLocalStorage::set_thread(thread);
 678 
 679   OSThread* osthread = thread->osthread();
 680   Monitor* sync = osthread->startThread_lock();
 681 
 682   osthread->set_thread_id(os::Bsd::gettid());
 683 
 684 #ifdef __APPLE__
 685   uint64_t unique_thread_id = locate_unique_thread_id(osthread->thread_id());
 686   guarantee(unique_thread_id != 0, "unique thread id was not found");
 687   osthread->set_unique_thread_id(unique_thread_id);
 688 #endif
 689   // initialize signal mask for this thread
 690   os::Bsd::hotspot_sigmask(thread);
 691 
 692   // initialize floating point control register
 693   os::Bsd::init_thread_fpu_state();
 694 
 695 #ifdef __APPLE__
 696   // register thread with objc gc
 697   if (objc_registerThreadWithCollectorFunction != NULL) {
 698     objc_registerThreadWithCollectorFunction();
 699   }
 700 #endif
 701 
 702   // handshaking with parent thread
 703   {
 704     MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
 705 
 706     // notify parent thread
 707     osthread->set_state(INITIALIZED);
 708     sync->notify_all();
 709 
 710     // wait until os::start_thread()
 711     while (osthread->get_state() == INITIALIZED) {
 712       sync->wait(Mutex::_no_safepoint_check_flag);
 713     }
 714   }
 715 
 716   // call one more level start routine
 717   thread->run();
 718 
 719   return 0;
 720 }
 721 
 722 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
 723   assert(thread->osthread() == NULL, "caller responsible");
 724 
 725   // Allocate the OSThread object
 726   OSThread* osthread = new OSThread(NULL, NULL);
 727   if (osthread == NULL) {
 728     return false;
 729   }
 730 
 731   // set the correct thread state
 732   osthread->set_thread_type(thr_type);
 733 
 734   // Initial state is ALLOCATED but not INITIALIZED
 735   osthread->set_state(ALLOCATED);
 736 
 737   thread->set_osthread(osthread);
 738 
 739   // init thread attributes
 740   pthread_attr_t attr;
 741   pthread_attr_init(&attr);
 742   pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 743 
 744   // calculate stack size if it's not specified by caller
 745   if (stack_size == 0) {
 746     stack_size = os::Bsd::default_stack_size(thr_type);
 747 
 748     switch (thr_type) {
 749     case os::java_thread:
 750       // Java threads use ThreadStackSize which default value can be
 751       // changed with the flag -Xss
 752       assert(JavaThread::stack_size_at_create() > 0, "this should be set");
 753       stack_size = JavaThread::stack_size_at_create();
 754       break;
 755     case os::compiler_thread:
 756       if (CompilerThreadStackSize > 0) {
 757         stack_size = (size_t)(CompilerThreadStackSize * K);
 758         break;
 759       } // else fall through:
 760         // use VMThreadStackSize if CompilerThreadStackSize is not defined
 761     case os::vm_thread:
 762     case os::pgc_thread:
 763     case os::cgc_thread:
 764     case os::watcher_thread:
 765       if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
 766       break;
 767     }
 768   }
 769 
 770   stack_size = MAX2(stack_size, os::Bsd::min_stack_allowed);
 771   pthread_attr_setstacksize(&attr, stack_size);
 772 
 773   ThreadState state;
 774 
 775   {
 776     pthread_t tid;
 777     int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
 778 
 779     pthread_attr_destroy(&attr);
 780 
 781     if (ret != 0) {
 782       if (PrintMiscellaneous && (Verbose || WizardMode)) {
 783         perror("pthread_create()");
 784       }
 785       // Need to clean up stuff we've allocated so far
 786       thread->set_osthread(NULL);
 787       delete osthread;
 788       return false;
 789     }
 790 
 791     // Store pthread info into the OSThread
 792     osthread->set_pthread_id(tid);
 793 
 794     // Wait until child thread is either initialized or aborted
 795     {
 796       Monitor* sync_with_child = osthread->startThread_lock();
 797       MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
 798       while ((state = osthread->get_state()) == ALLOCATED) {
 799         sync_with_child->wait(Mutex::_no_safepoint_check_flag);
 800       }
 801     }
 802 
 803   }
 804 
 805   // Aborted due to thread limit being reached
 806   if (state == ZOMBIE) {
 807     thread->set_osthread(NULL);
 808     delete osthread;
 809     return false;
 810   }
 811 
 812   // The thread is returned suspended (in state INITIALIZED),
 813   // and is started higher up in the call chain
 814   assert(state == INITIALIZED, "race condition");
 815   return true;
 816 }
 817 
 818 /////////////////////////////////////////////////////////////////////////////
 819 // attach existing thread
 820 
 821 // bootstrap the main thread
 822 bool os::create_main_thread(JavaThread* thread) {
 823   assert(os::Bsd::_main_thread == pthread_self(), "should be called inside main thread");
 824   return create_attached_thread(thread);
 825 }
 826 
 827 bool os::create_attached_thread(JavaThread* thread) {
 828 #ifdef ASSERT
 829   thread->verify_not_published();
 830 #endif
 831 
 832   // Allocate the OSThread object
 833   OSThread* osthread = new OSThread(NULL, NULL);
 834 
 835   if (osthread == NULL) {
 836     return false;
 837   }
 838 
 839   osthread->set_thread_id(os::Bsd::gettid());
 840 
 841   // Store pthread info into the OSThread
 842 #ifdef __APPLE__
 843   uint64_t unique_thread_id = locate_unique_thread_id(osthread->thread_id());
 844   guarantee(unique_thread_id != 0, "just checking");
 845   osthread->set_unique_thread_id(unique_thread_id);
 846 #endif
 847   osthread->set_pthread_id(::pthread_self());
 848 
 849   // initialize floating point control register
 850   os::Bsd::init_thread_fpu_state();
 851 
 852   // Initial thread state is RUNNABLE
 853   osthread->set_state(RUNNABLE);
 854 
 855   thread->set_osthread(osthread);
 856 
 857   // initialize signal mask for this thread
 858   // and save the caller's signal mask
 859   os::Bsd::hotspot_sigmask(thread);
 860 
 861   return true;
 862 }
 863 
 864 void os::pd_start_thread(Thread* thread) {
 865   OSThread * osthread = thread->osthread();
 866   assert(osthread->get_state() != INITIALIZED, "just checking");
 867   Monitor* sync_with_child = osthread->startThread_lock();
 868   MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
 869   sync_with_child->notify();
 870 }
 871 
 872 // Free Bsd resources related to the OSThread
 873 void os::free_thread(OSThread* osthread) {
 874   assert(osthread != NULL, "osthread not set");
 875 
 876   if (Thread::current()->osthread() == osthread) {
 877     // Restore caller's signal mask
 878     sigset_t sigmask = osthread->caller_sigmask();
 879     pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
 880   }
 881 
 882   delete osthread;
 883 }
 884 
 885 //////////////////////////////////////////////////////////////////////////////
 886 // thread local storage
 887 
 888 // Restore the thread pointer if the destructor is called. This is in case
 889 // someone from JNI code sets up a destructor with pthread_key_create to run
 890 // detachCurrentThread on thread death. Unless we restore the thread pointer we
 891 // will hang or crash. When detachCurrentThread is called the key will be set
 892 // to null and we will not be called again. If detachCurrentThread is never
 893 // called we could loop forever depending on the pthread implementation.
 894 static void restore_thread_pointer(void* p) {
 895   Thread* thread = (Thread*) p;
 896   os::thread_local_storage_at_put(ThreadLocalStorage::thread_index(), thread);
 897 }
 898 
 899 int os::allocate_thread_local_storage() {
 900   pthread_key_t key;
 901   int rslt = pthread_key_create(&key, restore_thread_pointer);
 902   assert(rslt == 0, "cannot allocate thread local storage");
 903   return (int)key;
 904 }
 905 
 906 // Note: This is currently not used by VM, as we don't destroy TLS key
 907 // on VM exit.
 908 void os::free_thread_local_storage(int index) {
 909   int rslt = pthread_key_delete((pthread_key_t)index);
 910   assert(rslt == 0, "invalid index");
 911 }
 912 
 913 void os::thread_local_storage_at_put(int index, void* value) {
 914   int rslt = pthread_setspecific((pthread_key_t)index, value);
 915   assert(rslt == 0, "pthread_setspecific failed");
 916 }
 917 
 918 extern "C" Thread* get_thread() {
 919   return ThreadLocalStorage::thread();
 920 }
 921 
 922 
 923 ////////////////////////////////////////////////////////////////////////////////
 924 // time support
 925 
 926 // Time since start-up in seconds to a fine granularity.
 927 // Used by VMSelfDestructTimer and the MemProfiler.
 928 double os::elapsedTime() {
 929 
 930   return ((double)os::elapsed_counter()) / os::elapsed_frequency();
 931 }
 932 
 933 jlong os::elapsed_counter() {
 934   return javaTimeNanos() - initial_time_count;
 935 }
 936 
 937 jlong os::elapsed_frequency() {
 938   return NANOSECS_PER_SEC; // nanosecond resolution
 939 }
 940 
 941 bool os::supports_vtime() { return true; }
 942 bool os::enable_vtime()   { return false; }
 943 bool os::vtime_enabled()  { return false; }
 944 
 945 double os::elapsedVTime() {
 946   // better than nothing, but not much
 947   return elapsedTime();
 948 }
 949 
 950 jlong os::javaTimeMillis() {
 951   timeval time;
 952   int status = gettimeofday(&time, NULL);
 953   assert(status != -1, "bsd error");
 954   return jlong(time.tv_sec) * 1000  +  jlong(time.tv_usec / 1000);
 955 }
 956 
 957 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
 958   timeval time;
 959   int status = gettimeofday(&time, NULL);
 960   assert(status != -1, "bsd error");
 961   seconds = jlong(time.tv_sec);
 962   nanos = jlong(time.tv_usec) * 1000;
 963 }
 964 
 965 #ifndef __APPLE__
 966   #ifndef CLOCK_MONOTONIC
 967     #define CLOCK_MONOTONIC (1)
 968   #endif
 969 #endif
 970 
 971 #ifdef __APPLE__
 972 void os::Bsd::clock_init() {
 973   mach_timebase_info(&_timebase_info);
 974 }
 975 #else
 976 void os::Bsd::clock_init() {
 977   struct timespec res;
 978   struct timespec tp;
 979   if (::clock_getres(CLOCK_MONOTONIC, &res) == 0 &&
 980       ::clock_gettime(CLOCK_MONOTONIC, &tp)  == 0) {
 981     // yes, monotonic clock is supported
 982     _clock_gettime = ::clock_gettime;
 983   }
 984 }
 985 #endif
 986 
 987 
 988 
 989 #ifdef __APPLE__
 990 
 991 jlong os::javaTimeNanos() {
 992   const uint64_t tm = mach_absolute_time();
 993   const uint64_t now = (tm * Bsd::_timebase_info.numer) / Bsd::_timebase_info.denom;
 994   const uint64_t prev = Bsd::_max_abstime;
 995   if (now <= prev) {
 996     return prev;   // same or retrograde time;
 997   }
 998   const uint64_t obsv = Atomic::cmpxchg(now, (volatile jlong*)&Bsd::_max_abstime, prev);
 999   assert(obsv >= prev, "invariant");   // Monotonicity
1000   // If the CAS succeeded then we're done and return "now".
1001   // If the CAS failed and the observed value "obsv" is >= now then
1002   // we should return "obsv".  If the CAS failed and now > obsv > prv then
1003   // some other thread raced this thread and installed a new value, in which case
1004   // we could either (a) retry the entire operation, (b) retry trying to install now
1005   // or (c) just return obsv.  We use (c).   No loop is required although in some cases
1006   // we might discard a higher "now" value in deference to a slightly lower but freshly
1007   // installed obsv value.   That's entirely benign -- it admits no new orderings compared
1008   // to (a) or (b) -- and greatly reduces coherence traffic.
1009   // We might also condition (c) on the magnitude of the delta between obsv and now.
1010   // Avoiding excessive CAS operations to hot RW locations is critical.
1011   // See https://blogs.oracle.com/dave/entry/cas_and_cache_trivia_invalidate
1012   return (prev == obsv) ? now : obsv;
1013 }
1014 
1015 #else // __APPLE__
1016 
1017 jlong os::javaTimeNanos() {
1018   if (os::supports_monotonic_clock()) {
1019     struct timespec tp;
1020     int status = Bsd::_clock_gettime(CLOCK_MONOTONIC, &tp);
1021     assert(status == 0, "gettime error");
1022     jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1023     return result;
1024   } else {
1025     timeval time;
1026     int status = gettimeofday(&time, NULL);
1027     assert(status != -1, "bsd error");
1028     jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1029     return 1000 * usecs;
1030   }
1031 }
1032 
1033 #endif // __APPLE__
1034 
1035 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1036   if (os::supports_monotonic_clock()) {
1037     info_ptr->max_value = ALL_64_BITS;
1038 
1039     // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1040     info_ptr->may_skip_backward = false;      // not subject to resetting or drifting
1041     info_ptr->may_skip_forward = false;       // not subject to resetting or drifting
1042   } else {
1043     // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1044     info_ptr->max_value = ALL_64_BITS;
1045 
1046     // gettimeofday is a real time clock so it skips
1047     info_ptr->may_skip_backward = true;
1048     info_ptr->may_skip_forward = true;
1049   }
1050 
1051   info_ptr->kind = JVMTI_TIMER_ELAPSED;                // elapsed not CPU time
1052 }
1053 
1054 // Return the real, user, and system times in seconds from an
1055 // arbitrary fixed point in the past.
1056 bool os::getTimesSecs(double* process_real_time,
1057                       double* process_user_time,
1058                       double* process_system_time) {
1059   struct tms ticks;
1060   clock_t real_ticks = times(&ticks);
1061 
1062   if (real_ticks == (clock_t) (-1)) {
1063     return false;
1064   } else {
1065     double ticks_per_second = (double) clock_tics_per_sec;
1066     *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1067     *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1068     *process_real_time = ((double) real_ticks) / ticks_per_second;
1069 
1070     return true;
1071   }
1072 }
1073 
1074 
1075 char * os::local_time_string(char *buf, size_t buflen) {
1076   struct tm t;
1077   time_t long_time;
1078   time(&long_time);
1079   localtime_r(&long_time, &t);
1080   jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1081                t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1082                t.tm_hour, t.tm_min, t.tm_sec);
1083   return buf;
1084 }
1085 
1086 struct tm* os::localtime_pd(const time_t* clock, struct tm*  res) {
1087   return localtime_r(clock, res);
1088 }
1089 
1090 ////////////////////////////////////////////////////////////////////////////////
1091 // runtime exit support
1092 
1093 // Note: os::shutdown() might be called very early during initialization, or
1094 // called from signal handler. Before adding something to os::shutdown(), make
1095 // sure it is async-safe and can handle partially initialized VM.
1096 void os::shutdown() {
1097 
1098   // allow PerfMemory to attempt cleanup of any persistent resources
1099   perfMemory_exit();
1100 
1101   // needs to remove object in file system
1102   AttachListener::abort();
1103 
1104   // flush buffered output, finish log files
1105   ostream_abort();
1106 
1107   // Check for abort hook
1108   abort_hook_t abort_hook = Arguments::abort_hook();
1109   if (abort_hook != NULL) {
1110     abort_hook();
1111   }
1112 
1113 }
1114 
1115 // Note: os::abort() might be called very early during initialization, or
1116 // called from signal handler. Before adding something to os::abort(), make
1117 // sure it is async-safe and can handle partially initialized VM.
1118 void os::abort(bool dump_core, void* siginfo, void* context) {
1119   os::shutdown();
1120   if (dump_core) {
1121 #ifndef PRODUCT
1122     fdStream out(defaultStream::output_fd());
1123     out.print_raw("Current thread is ");
1124     char buf[16];
1125     jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1126     out.print_raw_cr(buf);
1127     out.print_raw_cr("Dumping core ...");
1128 #endif
1129     ::abort(); // dump core
1130   }
1131 
1132   ::exit(1);
1133 }
1134 
1135 // Die immediately, no exit hook, no abort hook, no cleanup.
1136 void os::die() {
1137   // _exit() on BsdThreads only kills current thread
1138   ::abort();
1139 }
1140 
1141 // This method is a copy of JDK's sysGetLastErrorString
1142 // from src/solaris/hpi/src/system_md.c
1143 
1144 size_t os::lasterror(char *buf, size_t len) {
1145   if (errno == 0)  return 0;
1146 
1147   const char *s = ::strerror(errno);
1148   size_t n = ::strlen(s);
1149   if (n >= len) {
1150     n = len - 1;
1151   }
1152   ::strncpy(buf, s, n);
1153   buf[n] = '\0';
1154   return n;
1155 }
1156 
1157 // Information of current thread in variety of formats
1158 pid_t os::Bsd::gettid() {
1159   int retval = -1;
1160 
1161 #ifdef __APPLE__ //XNU kernel
1162   // despite the fact mach port is actually not a thread id use it
1163   // instead of syscall(SYS_thread_selfid) as it certainly fits to u4
1164   retval = ::pthread_mach_thread_np(::pthread_self());
1165   guarantee(retval != 0, "just checking");
1166   return retval;
1167 
1168 #else
1169   #ifdef __FreeBSD__
1170   retval = syscall(SYS_thr_self);
1171   #else
1172     #ifdef __OpenBSD__
1173   retval = syscall(SYS_getthrid);
1174     #else
1175       #ifdef __NetBSD__
1176   retval = (pid_t) syscall(SYS__lwp_self);
1177       #endif
1178     #endif
1179   #endif
1180 #endif
1181 
1182   if (retval == -1) {
1183     return getpid();
1184   }
1185 }
1186 
1187 intx os::current_thread_id() {
1188 #ifdef __APPLE__
1189   return (intx)::pthread_mach_thread_np(::pthread_self());
1190 #else
1191   return (intx)::pthread_self();
1192 #endif
1193 }
1194 
1195 int os::current_process_id() {
1196 
1197   // Under the old bsd thread library, bsd gives each thread
1198   // its own process id. Because of this each thread will return
1199   // a different pid if this method were to return the result
1200   // of getpid(2). Bsd provides no api that returns the pid
1201   // of the launcher thread for the vm. This implementation
1202   // returns a unique pid, the pid of the launcher thread
1203   // that starts the vm 'process'.
1204 
1205   // Under the NPTL, getpid() returns the same pid as the
1206   // launcher thread rather than a unique pid per thread.
1207   // Use gettid() if you want the old pre NPTL behaviour.
1208 
1209   // if you are looking for the result of a call to getpid() that
1210   // returns a unique pid for the calling thread, then look at the
1211   // OSThread::thread_id() method in osThread_bsd.hpp file
1212 
1213   return (int)(_initial_pid ? _initial_pid : getpid());
1214 }
1215 
1216 // DLL functions
1217 
1218 #define JNI_LIB_PREFIX "lib"
1219 #ifdef __APPLE__
1220   #define JNI_LIB_SUFFIX ".dylib"
1221 #else
1222   #define JNI_LIB_SUFFIX ".so"
1223 #endif
1224 
1225 const char* os::dll_file_extension() { return JNI_LIB_SUFFIX; }
1226 
1227 // This must be hard coded because it's the system's temporary
1228 // directory not the java application's temp directory, ala java.io.tmpdir.
1229 #ifdef __APPLE__
1230 // macosx has a secure per-user temporary directory
1231 char temp_path_storage[PATH_MAX];
1232 const char* os::get_temp_directory() {
1233   static char *temp_path = NULL;
1234   if (temp_path == NULL) {
1235     int pathSize = confstr(_CS_DARWIN_USER_TEMP_DIR, temp_path_storage, PATH_MAX);
1236     if (pathSize == 0 || pathSize > PATH_MAX) {
1237       strlcpy(temp_path_storage, "/tmp/", sizeof(temp_path_storage));
1238     }
1239     temp_path = temp_path_storage;
1240   }
1241   return temp_path;
1242 }
1243 #else // __APPLE__
1244 const char* os::get_temp_directory() { return "/tmp"; }
1245 #endif // __APPLE__
1246 
1247 static bool file_exists(const char* filename) {
1248   struct stat statbuf;
1249   if (filename == NULL || strlen(filename) == 0) {
1250     return false;
1251   }
1252   return os::stat(filename, &statbuf) == 0;
1253 }
1254 
1255 bool os::dll_build_name(char* buffer, size_t buflen,
1256                         const char* pname, const char* fname) {
1257   bool retval = false;
1258   // Copied from libhpi
1259   const size_t pnamelen = pname ? strlen(pname) : 0;
1260 
1261   // Return error on buffer overflow.
1262   if (pnamelen + strlen(fname) + strlen(JNI_LIB_PREFIX) + strlen(JNI_LIB_SUFFIX) + 2 > buflen) {
1263     return retval;
1264   }
1265 
1266   if (pnamelen == 0) {
1267     snprintf(buffer, buflen, JNI_LIB_PREFIX "%s" JNI_LIB_SUFFIX, fname);
1268     retval = true;
1269   } else if (strchr(pname, *os::path_separator()) != NULL) {
1270     int n;
1271     char** pelements = split_path(pname, &n);
1272     if (pelements == NULL) {
1273       return false;
1274     }
1275     for (int i = 0; i < n; i++) {
1276       // Really shouldn't be NULL, but check can't hurt
1277       if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1278         continue; // skip the empty path values
1279       }
1280       snprintf(buffer, buflen, "%s/" JNI_LIB_PREFIX "%s" JNI_LIB_SUFFIX,
1281                pelements[i], fname);
1282       if (file_exists(buffer)) {
1283         retval = true;
1284         break;
1285       }
1286     }
1287     // release the storage
1288     for (int i = 0; i < n; i++) {
1289       if (pelements[i] != NULL) {
1290         FREE_C_HEAP_ARRAY(char, pelements[i]);
1291       }
1292     }
1293     if (pelements != NULL) {
1294       FREE_C_HEAP_ARRAY(char*, pelements);
1295     }
1296   } else {
1297     snprintf(buffer, buflen, "%s/" JNI_LIB_PREFIX "%s" JNI_LIB_SUFFIX, pname, fname);
1298     retval = true;
1299   }
1300   return retval;
1301 }
1302 
1303 // check if addr is inside libjvm.so
1304 bool os::address_is_in_vm(address addr) {
1305   static address libjvm_base_addr;
1306   Dl_info dlinfo;
1307 
1308   if (libjvm_base_addr == NULL) {
1309     if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1310       libjvm_base_addr = (address)dlinfo.dli_fbase;
1311     }
1312     assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1313   }
1314 
1315   if (dladdr((void *)addr, &dlinfo) != 0) {
1316     if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1317   }
1318 
1319   return false;
1320 }
1321 
1322 
1323 #define MACH_MAXSYMLEN 256
1324 
1325 bool os::dll_address_to_function_name(address addr, char *buf,
1326                                       int buflen, int *offset,
1327                                       bool demangle) {
1328   // buf is not optional, but offset is optional
1329   assert(buf != NULL, "sanity check");
1330 
1331   Dl_info dlinfo;
1332   char localbuf[MACH_MAXSYMLEN];
1333 
1334   if (dladdr((void*)addr, &dlinfo) != 0) {
1335     // see if we have a matching symbol
1336     if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1337       if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1338         jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1339       }
1340       if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1341       return true;
1342     }
1343     // no matching symbol so try for just file info
1344     if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1345       if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1346                           buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1347         return true;
1348       }
1349     }
1350 
1351     // Handle non-dynamic manually:
1352     if (dlinfo.dli_fbase != NULL &&
1353         Decoder::decode(addr, localbuf, MACH_MAXSYMLEN, offset,
1354                         dlinfo.dli_fbase)) {
1355       if (!(demangle && Decoder::demangle(localbuf, buf, buflen))) {
1356         jio_snprintf(buf, buflen, "%s", localbuf);
1357       }
1358       return true;
1359     }
1360   }
1361   buf[0] = '\0';
1362   if (offset != NULL) *offset = -1;
1363   return false;
1364 }
1365 
1366 // ported from solaris version
1367 bool os::dll_address_to_library_name(address addr, char* buf,
1368                                      int buflen, int* offset) {
1369   // buf is not optional, but offset is optional
1370   assert(buf != NULL, "sanity check");
1371 
1372   Dl_info dlinfo;
1373 
1374   if (dladdr((void*)addr, &dlinfo) != 0) {
1375     if (dlinfo.dli_fname != NULL) {
1376       jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1377     }
1378     if (dlinfo.dli_fbase != NULL && offset != NULL) {
1379       *offset = addr - (address)dlinfo.dli_fbase;
1380     }
1381     return true;
1382   }
1383 
1384   buf[0] = '\0';
1385   if (offset) *offset = -1;
1386   return false;
1387 }
1388 
1389 // Loads .dll/.so and
1390 // in case of error it checks if .dll/.so was built for the
1391 // same architecture as Hotspot is running on
1392 
1393 #ifdef __APPLE__
1394 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1395 #ifdef STATIC_BUILD
1396   return os::get_default_process_handle();
1397 #else
1398   void * result= ::dlopen(filename, RTLD_LAZY);
1399   if (result != NULL) {
1400     // Successful loading
1401     return result;
1402   }
1403 
1404   // Read system error message into ebuf
1405   ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1406   ebuf[ebuflen-1]='\0';
1407 
1408   return NULL;
1409 #endif // STATIC_BUILD
1410 }
1411 #else
1412 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1413 #ifdef STATIC_BUILD
1414   return os::get_default_process_handle();
1415 #else
1416   void * result= ::dlopen(filename, RTLD_LAZY);
1417   if (result != NULL) {
1418     // Successful loading
1419     return result;
1420   }
1421 
1422   Elf32_Ehdr elf_head;
1423 
1424   // Read system error message into ebuf
1425   // It may or may not be overwritten below
1426   ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1427   ebuf[ebuflen-1]='\0';
1428   int diag_msg_max_length=ebuflen-strlen(ebuf);
1429   char* diag_msg_buf=ebuf+strlen(ebuf);
1430 
1431   if (diag_msg_max_length==0) {
1432     // No more space in ebuf for additional diagnostics message
1433     return NULL;
1434   }
1435 
1436 
1437   int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1438 
1439   if (file_descriptor < 0) {
1440     // Can't open library, report dlerror() message
1441     return NULL;
1442   }
1443 
1444   bool failed_to_read_elf_head=
1445     (sizeof(elf_head)!=
1446      (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1447 
1448   ::close(file_descriptor);
1449   if (failed_to_read_elf_head) {
1450     // file i/o error - report dlerror() msg
1451     return NULL;
1452   }
1453 
1454   typedef struct {
1455     Elf32_Half  code;         // Actual value as defined in elf.h
1456     Elf32_Half  compat_class; // Compatibility of archs at VM's sense
1457     char        elf_class;    // 32 or 64 bit
1458     char        endianess;    // MSB or LSB
1459     char*       name;         // String representation
1460   } arch_t;
1461 
1462   #ifndef EM_486
1463     #define EM_486          6               /* Intel 80486 */
1464   #endif
1465 
1466   #ifndef EM_MIPS_RS3_LE
1467     #define EM_MIPS_RS3_LE  10              /* MIPS */
1468   #endif
1469 
1470   #ifndef EM_PPC64
1471     #define EM_PPC64        21              /* PowerPC64 */
1472   #endif
1473 
1474   #ifndef EM_S390
1475     #define EM_S390         22              /* IBM System/390 */
1476   #endif
1477 
1478   #ifndef EM_IA_64
1479     #define EM_IA_64        50              /* HP/Intel IA-64 */
1480   #endif
1481 
1482   #ifndef EM_X86_64
1483     #define EM_X86_64       62              /* AMD x86-64 */
1484   #endif
1485 
1486   static const arch_t arch_array[]={
1487     {EM_386,         EM_386,     ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1488     {EM_486,         EM_386,     ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1489     {EM_IA_64,       EM_IA_64,   ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1490     {EM_X86_64,      EM_X86_64,  ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1491     {EM_SPARC,       EM_SPARC,   ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1492     {EM_SPARC32PLUS, EM_SPARC,   ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1493     {EM_SPARCV9,     EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1494     {EM_PPC,         EM_PPC,     ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1495     {EM_PPC64,       EM_PPC64,   ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1496     {EM_ARM,         EM_ARM,     ELFCLASS32,   ELFDATA2LSB, (char*)"ARM"},
1497     {EM_S390,        EM_S390,    ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1498     {EM_ALPHA,       EM_ALPHA,   ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1499     {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1500     {EM_MIPS,        EM_MIPS,    ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1501     {EM_PARISC,      EM_PARISC,  ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1502     {EM_68K,         EM_68K,     ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1503   };
1504 
1505   #if  (defined IA32)
1506   static  Elf32_Half running_arch_code=EM_386;
1507   #elif   (defined AMD64)
1508   static  Elf32_Half running_arch_code=EM_X86_64;
1509   #elif  (defined IA64)
1510   static  Elf32_Half running_arch_code=EM_IA_64;
1511   #elif  (defined __sparc) && (defined _LP64)
1512   static  Elf32_Half running_arch_code=EM_SPARCV9;
1513   #elif  (defined __sparc) && (!defined _LP64)
1514   static  Elf32_Half running_arch_code=EM_SPARC;
1515   #elif  (defined __powerpc64__)
1516   static  Elf32_Half running_arch_code=EM_PPC64;
1517   #elif  (defined __powerpc__)
1518   static  Elf32_Half running_arch_code=EM_PPC;
1519   #elif  (defined ARM)
1520   static  Elf32_Half running_arch_code=EM_ARM;
1521   #elif  (defined S390)
1522   static  Elf32_Half running_arch_code=EM_S390;
1523   #elif  (defined ALPHA)
1524   static  Elf32_Half running_arch_code=EM_ALPHA;
1525   #elif  (defined MIPSEL)
1526   static  Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1527   #elif  (defined PARISC)
1528   static  Elf32_Half running_arch_code=EM_PARISC;
1529   #elif  (defined MIPS)
1530   static  Elf32_Half running_arch_code=EM_MIPS;
1531   #elif  (defined M68K)
1532   static  Elf32_Half running_arch_code=EM_68K;
1533   #else
1534     #error Method os::dll_load requires that one of following is defined:\
1535          IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1536   #endif
1537 
1538   // Identify compatability class for VM's architecture and library's architecture
1539   // Obtain string descriptions for architectures
1540 
1541   arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1542   int running_arch_index=-1;
1543 
1544   for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1545     if (running_arch_code == arch_array[i].code) {
1546       running_arch_index    = i;
1547     }
1548     if (lib_arch.code == arch_array[i].code) {
1549       lib_arch.compat_class = arch_array[i].compat_class;
1550       lib_arch.name         = arch_array[i].name;
1551     }
1552   }
1553 
1554   assert(running_arch_index != -1,
1555          "Didn't find running architecture code (running_arch_code) in arch_array");
1556   if (running_arch_index == -1) {
1557     // Even though running architecture detection failed
1558     // we may still continue with reporting dlerror() message
1559     return NULL;
1560   }
1561 
1562   if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1563     ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1564     return NULL;
1565   }
1566 
1567 #ifndef S390
1568   if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1569     ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1570     return NULL;
1571   }
1572 #endif // !S390
1573 
1574   if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1575     if (lib_arch.name!=NULL) {
1576       ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1577                  " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1578                  lib_arch.name, arch_array[running_arch_index].name);
1579     } else {
1580       ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1581                  " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1582                  lib_arch.code,
1583                  arch_array[running_arch_index].name);
1584     }
1585   }
1586 
1587   return NULL;
1588 #endif // STATIC_BUILD
1589 }
1590 #endif // !__APPLE__
1591 
1592 void* os::get_default_process_handle() {
1593 #ifdef __APPLE__
1594   // MacOS X needs to use RTLD_FIRST instead of RTLD_LAZY
1595   // to avoid finding unexpected symbols on second (or later)
1596   // loads of a library.
1597   return (void*)::dlopen(NULL, RTLD_FIRST);
1598 #else
1599   return (void*)::dlopen(NULL, RTLD_LAZY);
1600 #endif
1601 }
1602 
1603 // XXX: Do we need a lock around this as per Linux?
1604 void* os::dll_lookup(void* handle, const char* name) {
1605   return dlsym(handle, name);
1606 }
1607 
1608 int _print_dll_info_cb(const char * name, address base_address, address top_address, void * param) {
1609   outputStream * out = (outputStream *) param;
1610   out->print_cr(PTR_FORMAT " \t%s", base_address, name);
1611   return 0;
1612 }
1613 
1614 void os::print_dll_info(outputStream *st) {
1615   st->print_cr("Dynamic libraries:");
1616   if (get_loaded_modules_info(_print_dll_info_cb, (void *)st)) {
1617     st->print_cr("Error: Cannot print dynamic libraries.");
1618   }
1619 }
1620 
1621 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
1622 #ifdef RTLD_DI_LINKMAP
1623   Dl_info dli;
1624   void *handle;
1625   Link_map *map;
1626   Link_map *p;
1627 
1628   if (dladdr(CAST_FROM_FN_PTR(void *, os::print_dll_info), &dli) == 0 ||
1629       dli.dli_fname == NULL) {
1630     return 1;
1631   }
1632   handle = dlopen(dli.dli_fname, RTLD_LAZY);
1633   if (handle == NULL) {
1634     return 1;
1635   }
1636   dlinfo(handle, RTLD_DI_LINKMAP, &map);
1637   if (map == NULL) {
1638     dlclose(handle);
1639     return 1;
1640   }
1641 
1642   while (map->l_prev != NULL)
1643     map = map->l_prev;
1644 
1645   while (map != NULL) {
1646     // Value for top_address is returned as 0 since we don't have any information about module size
1647     if (callback(map->l_name, (address)map->l_addr, (address)0, param)) {
1648       dlclose(handle);
1649       return 1;
1650     }
1651     map = map->l_next;
1652   }
1653 
1654   dlclose(handle);
1655 #elif defined(__APPLE__)
1656   for (uint32_t i = 1; i < _dyld_image_count(); i++) {
1657     // Value for top_address is returned as 0 since we don't have any information about module size
1658     if (callback(_dyld_get_image_name(i), (address)_dyld_get_image_header(i), (address)0, param)) {
1659       return 1;
1660     }
1661   }
1662   return 0;
1663 #else
1664   return 1;
1665 #endif
1666 }
1667 
1668 void os::get_summary_os_info(char* buf, size_t buflen) {
1669   // These buffers are small because we want this to be brief
1670   // and not use a lot of stack while generating the hs_err file.
1671   char os[100];
1672   size_t size = sizeof(os);
1673   int mib_kern[] = { CTL_KERN, KERN_OSTYPE };
1674   if (sysctl(mib_kern, 2, os, &size, NULL, 0) < 0) {
1675 #ifdef __APPLE__
1676       strncpy(os, "Darwin", sizeof(os));
1677 #elif __OpenBSD__
1678       strncpy(os, "OpenBSD", sizeof(os));
1679 #else
1680       strncpy(os, "BSD", sizeof(os));
1681 #endif
1682   }
1683 
1684   char release[100];
1685   size = sizeof(release);
1686   int mib_release[] = { CTL_KERN, KERN_OSRELEASE };
1687   if (sysctl(mib_release, 2, release, &size, NULL, 0) < 0) {
1688       // if error, leave blank
1689       strncpy(release, "", sizeof(release));
1690   }
1691   snprintf(buf, buflen, "%s %s", os, release);
1692 }
1693 
1694 void os::print_os_info_brief(outputStream* st) {
1695   os::Posix::print_uname_info(st);
1696 }
1697 
1698 void os::print_os_info(outputStream* st) {
1699   st->print("OS:");
1700 
1701   os::Posix::print_uname_info(st);
1702 
1703   os::Posix::print_rlimit_info(st);
1704 
1705   os::Posix::print_load_average(st);
1706 }
1707 
1708 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
1709   // Nothing to do for now.
1710 }
1711 
1712 void os::get_summary_cpu_info(char* buf, size_t buflen) {
1713   unsigned int mhz;
1714   size_t size = sizeof(mhz);
1715   int mib[] = { CTL_HW, HW_CPU_FREQ };
1716   if (sysctl(mib, 2, &mhz, &size, NULL, 0) < 0) {
1717     mhz = 1;  // looks like an error but can be divided by
1718   } else {
1719     mhz /= 1000000;  // reported in millions
1720   }
1721 
1722   char model[100];
1723   size = sizeof(model);
1724   int mib_model[] = { CTL_HW, HW_MODEL };
1725   if (sysctl(mib_model, 2, model, &size, NULL, 0) < 0) {
1726     strncpy(model, cpu_arch, sizeof(model));
1727   }
1728 
1729   char machine[100];
1730   size = sizeof(machine);
1731   int mib_machine[] = { CTL_HW, HW_MACHINE };
1732   if (sysctl(mib_machine, 2, machine, &size, NULL, 0) < 0) {
1733       strncpy(machine, "", sizeof(machine));
1734   }
1735 
1736   snprintf(buf, buflen, "%s %s %d MHz", model, machine, mhz);
1737 }
1738 
1739 void os::print_memory_info(outputStream* st) {
1740 
1741   st->print("Memory:");
1742   st->print(" %dk page", os::vm_page_size()>>10);
1743 
1744   st->print(", physical " UINT64_FORMAT "k",
1745             os::physical_memory() >> 10);
1746   st->print("(" UINT64_FORMAT "k free)",
1747             os::available_memory() >> 10);
1748   st->cr();
1749 }
1750 
1751 void os::print_siginfo(outputStream* st, void* siginfo) {
1752   const siginfo_t* si = (const siginfo_t*)siginfo;
1753 
1754   os::Posix::print_siginfo_brief(st, si);
1755 
1756   if (si && (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
1757       UseSharedSpaces) {
1758     FileMapInfo* mapinfo = FileMapInfo::current_info();
1759     if (mapinfo->is_in_shared_space(si->si_addr)) {
1760       st->print("\n\nError accessing class data sharing archive."   \
1761                 " Mapped file inaccessible during execution, "      \
1762                 " possible disk/network problem.");
1763     }
1764   }
1765   st->cr();
1766 }
1767 
1768 
1769 static void print_signal_handler(outputStream* st, int sig,
1770                                  char* buf, size_t buflen);
1771 
1772 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
1773   st->print_cr("Signal Handlers:");
1774   print_signal_handler(st, SIGSEGV, buf, buflen);
1775   print_signal_handler(st, SIGBUS , buf, buflen);
1776   print_signal_handler(st, SIGFPE , buf, buflen);
1777   print_signal_handler(st, SIGPIPE, buf, buflen);
1778   print_signal_handler(st, SIGXFSZ, buf, buflen);
1779   print_signal_handler(st, SIGILL , buf, buflen);
1780   print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
1781   print_signal_handler(st, SR_signum, buf, buflen);
1782   print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
1783   print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
1784   print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
1785   print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
1786 }
1787 
1788 static char saved_jvm_path[MAXPATHLEN] = {0};
1789 
1790 // Find the full path to the current module, libjvm
1791 void os::jvm_path(char *buf, jint buflen) {
1792   // Error checking.
1793   if (buflen < MAXPATHLEN) {
1794     assert(false, "must use a large-enough buffer");
1795     buf[0] = '\0';
1796     return;
1797   }
1798   // Lazy resolve the path to current module.
1799   if (saved_jvm_path[0] != 0) {
1800     strcpy(buf, saved_jvm_path);
1801     return;
1802   }
1803 
1804   char dli_fname[MAXPATHLEN];
1805   bool ret = dll_address_to_library_name(
1806                                          CAST_FROM_FN_PTR(address, os::jvm_path),
1807                                          dli_fname, sizeof(dli_fname), NULL);
1808   assert(ret, "cannot locate libjvm");
1809   char *rp = NULL;
1810   if (ret && dli_fname[0] != '\0') {
1811     rp = realpath(dli_fname, buf);
1812   }
1813   if (rp == NULL) {
1814     return;
1815   }
1816 
1817   if (Arguments::sun_java_launcher_is_altjvm()) {
1818     // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
1819     // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so"
1820     // or "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.dylib". If "/jre/lib/"
1821     // appears at the right place in the string, then assume we are
1822     // installed in a JDK and we're done. Otherwise, check for a
1823     // JAVA_HOME environment variable and construct a path to the JVM
1824     // being overridden.
1825 
1826     const char *p = buf + strlen(buf) - 1;
1827     for (int count = 0; p > buf && count < 5; ++count) {
1828       for (--p; p > buf && *p != '/'; --p)
1829         /* empty */ ;
1830     }
1831 
1832     if (strncmp(p, "/jre/lib/", 9) != 0) {
1833       // Look for JAVA_HOME in the environment.
1834       char* java_home_var = ::getenv("JAVA_HOME");
1835       if (java_home_var != NULL && java_home_var[0] != 0) {
1836         char* jrelib_p;
1837         int len;
1838 
1839         // Check the current module name "libjvm"
1840         p = strrchr(buf, '/');
1841         assert(strstr(p, "/libjvm") == p, "invalid library name");
1842 
1843         rp = realpath(java_home_var, buf);
1844         if (rp == NULL) {
1845           return;
1846         }
1847 
1848         // determine if this is a legacy image or modules image
1849         // modules image doesn't have "jre" subdirectory
1850         len = strlen(buf);
1851         assert(len < buflen, "Ran out of buffer space");
1852         jrelib_p = buf + len;
1853 
1854         // Add the appropriate library subdir
1855         snprintf(jrelib_p, buflen-len, "/jre/lib");
1856         if (0 != access(buf, F_OK)) {
1857           snprintf(jrelib_p, buflen-len, "/lib");
1858         }
1859 
1860         // Add the appropriate client or server subdir
1861         len = strlen(buf);
1862         jrelib_p = buf + len;
1863         snprintf(jrelib_p, buflen-len, "/%s", COMPILER_VARIANT);
1864         if (0 != access(buf, F_OK)) {
1865           snprintf(jrelib_p, buflen-len, "%s", "");
1866         }
1867 
1868         // If the path exists within JAVA_HOME, add the JVM library name
1869         // to complete the path to JVM being overridden.  Otherwise fallback
1870         // to the path to the current library.
1871         if (0 == access(buf, F_OK)) {
1872           // Use current module name "libjvm"
1873           len = strlen(buf);
1874           snprintf(buf + len, buflen-len, "/libjvm%s", JNI_LIB_SUFFIX);
1875         } else {
1876           // Fall back to path of current library
1877           rp = realpath(dli_fname, buf);
1878           if (rp == NULL) {
1879             return;
1880           }
1881         }
1882       }
1883     }
1884   }
1885 
1886   strncpy(saved_jvm_path, buf, MAXPATHLEN);
1887   saved_jvm_path[MAXPATHLEN - 1] = '\0';
1888 }
1889 
1890 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
1891   // no prefix required, not even "_"
1892 }
1893 
1894 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
1895   // no suffix required
1896 }
1897 
1898 ////////////////////////////////////////////////////////////////////////////////
1899 // sun.misc.Signal support
1900 
1901 static volatile jint sigint_count = 0;
1902 
1903 static void UserHandler(int sig, void *siginfo, void *context) {
1904   // 4511530 - sem_post is serialized and handled by the manager thread. When
1905   // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
1906   // don't want to flood the manager thread with sem_post requests.
1907   if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) {
1908     return;
1909   }
1910 
1911   // Ctrl-C is pressed during error reporting, likely because the error
1912   // handler fails to abort. Let VM die immediately.
1913   if (sig == SIGINT && is_error_reported()) {
1914     os::die();
1915   }
1916 
1917   os::signal_notify(sig);
1918 }
1919 
1920 void* os::user_handler() {
1921   return CAST_FROM_FN_PTR(void*, UserHandler);
1922 }
1923 
1924 extern "C" {
1925   typedef void (*sa_handler_t)(int);
1926   typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
1927 }
1928 
1929 void* os::signal(int signal_number, void* handler) {
1930   struct sigaction sigAct, oldSigAct;
1931 
1932   sigfillset(&(sigAct.sa_mask));
1933   sigAct.sa_flags   = SA_RESTART|SA_SIGINFO;
1934   sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
1935 
1936   if (sigaction(signal_number, &sigAct, &oldSigAct)) {
1937     // -1 means registration failed
1938     return (void *)-1;
1939   }
1940 
1941   return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
1942 }
1943 
1944 void os::signal_raise(int signal_number) {
1945   ::raise(signal_number);
1946 }
1947 
1948 // The following code is moved from os.cpp for making this
1949 // code platform specific, which it is by its very nature.
1950 
1951 // Will be modified when max signal is changed to be dynamic
1952 int os::sigexitnum_pd() {
1953   return NSIG;
1954 }
1955 
1956 // a counter for each possible signal value
1957 static volatile jint pending_signals[NSIG+1] = { 0 };
1958 
1959 // Bsd(POSIX) specific hand shaking semaphore.
1960 #ifdef __APPLE__
1961 typedef semaphore_t os_semaphore_t;
1962 
1963   #define SEM_INIT(sem, value)    semaphore_create(mach_task_self(), &sem, SYNC_POLICY_FIFO, value)
1964   #define SEM_WAIT(sem)           semaphore_wait(sem)
1965   #define SEM_POST(sem)           semaphore_signal(sem)
1966   #define SEM_DESTROY(sem)        semaphore_destroy(mach_task_self(), sem)
1967 #else
1968 typedef sem_t os_semaphore_t;
1969 
1970   #define SEM_INIT(sem, value)    sem_init(&sem, 0, value)
1971   #define SEM_WAIT(sem)           sem_wait(&sem)
1972   #define SEM_POST(sem)           sem_post(&sem)
1973   #define SEM_DESTROY(sem)        sem_destroy(&sem)
1974 #endif
1975 
1976 #ifdef __APPLE__
1977 // OS X doesn't support unamed POSIX semaphores, so the implementation in os_posix.cpp can't be used.
1978 
1979 static const char* sem_init_strerror(kern_return_t value) {
1980   switch (value) {
1981     case KERN_INVALID_ARGUMENT:  return "Invalid argument";
1982     case KERN_RESOURCE_SHORTAGE: return "Resource shortage";
1983     default:                     return "Unknown";
1984   }
1985 }
1986 
1987 OSXSemaphore::OSXSemaphore(uint value) {
1988   kern_return_t ret = SEM_INIT(_semaphore, value);
1989 
1990   guarantee(ret == KERN_SUCCESS, "Failed to create semaphore: %s", sem_init_strerror(ret));
1991 }
1992 
1993 OSXSemaphore::~OSXSemaphore() {
1994   SEM_DESTROY(_semaphore);
1995 }
1996 
1997 void OSXSemaphore::signal(uint count) {
1998   for (uint i = 0; i < count; i++) {
1999     kern_return_t ret = SEM_POST(_semaphore);
2000 
2001     assert(ret == KERN_SUCCESS, "Failed to signal semaphore");
2002   }
2003 }
2004 
2005 void OSXSemaphore::wait() {
2006   kern_return_t ret;
2007   while ((ret = SEM_WAIT(_semaphore)) == KERN_ABORTED) {
2008     // Semaphore was interrupted. Retry.
2009   }
2010   assert(ret == KERN_SUCCESS, "Failed to wait on semaphore");
2011 }
2012 
2013 jlong OSXSemaphore::currenttime() {
2014   struct timeval tv;
2015   gettimeofday(&tv, NULL);
2016   return (tv.tv_sec * NANOSECS_PER_SEC) + (tv.tv_usec * 1000);
2017 }
2018 
2019 bool OSXSemaphore::trywait() {
2020   return timedwait(0, 0);
2021 }
2022 
2023 bool OSXSemaphore::timedwait(unsigned int sec, int nsec) {
2024   kern_return_t kr = KERN_ABORTED;
2025   mach_timespec_t waitspec;
2026   waitspec.tv_sec = sec;
2027   waitspec.tv_nsec = nsec;
2028 
2029   jlong starttime = currenttime();
2030 
2031   kr = semaphore_timedwait(_semaphore, waitspec);
2032   while (kr == KERN_ABORTED) {
2033     jlong totalwait = (sec * NANOSECS_PER_SEC) + nsec;
2034 
2035     jlong current = currenttime();
2036     jlong passedtime = current - starttime;
2037 
2038     if (passedtime >= totalwait) {
2039       waitspec.tv_sec = 0;
2040       waitspec.tv_nsec = 0;
2041     } else {
2042       jlong waittime = totalwait - (current - starttime);
2043       waitspec.tv_sec = waittime / NANOSECS_PER_SEC;
2044       waitspec.tv_nsec = waittime % NANOSECS_PER_SEC;
2045     }
2046 
2047     kr = semaphore_timedwait(_semaphore, waitspec);
2048   }
2049 
2050   return kr == KERN_SUCCESS;
2051 }
2052 
2053 #else
2054 // Use POSIX implementation of semaphores.
2055 
2056 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) {
2057   struct timespec ts;
2058   unpackTime(&ts, false, (sec * NANOSECS_PER_SEC) + nsec);
2059 
2060   return ts;
2061 }
2062 
2063 #endif // __APPLE__
2064 
2065 static os_semaphore_t sig_sem;
2066 
2067 #ifdef __APPLE__
2068 static OSXSemaphore sr_semaphore;
2069 #else
2070 static PosixSemaphore sr_semaphore;
2071 #endif
2072 
2073 void os::signal_init_pd() {
2074   // Initialize signal structures
2075   ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2076 
2077   // Initialize signal semaphore
2078   ::SEM_INIT(sig_sem, 0);
2079 }
2080 
2081 void os::signal_notify(int sig) {
2082   Atomic::inc(&pending_signals[sig]);
2083   ::SEM_POST(sig_sem);
2084 }
2085 
2086 static int check_pending_signals(bool wait) {
2087   Atomic::store(0, &sigint_count);
2088   for (;;) {
2089     for (int i = 0; i < NSIG + 1; i++) {
2090       jint n = pending_signals[i];
2091       if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2092         return i;
2093       }
2094     }
2095     if (!wait) {
2096       return -1;
2097     }
2098     JavaThread *thread = JavaThread::current();
2099     ThreadBlockInVM tbivm(thread);
2100 
2101     bool threadIsSuspended;
2102     do {
2103       thread->set_suspend_equivalent();
2104       // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2105       ::SEM_WAIT(sig_sem);
2106 
2107       // were we externally suspended while we were waiting?
2108       threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2109       if (threadIsSuspended) {
2110         // The semaphore has been incremented, but while we were waiting
2111         // another thread suspended us. We don't want to continue running
2112         // while suspended because that would surprise the thread that
2113         // suspended us.
2114         ::SEM_POST(sig_sem);
2115 
2116         thread->java_suspend_self();
2117       }
2118     } while (threadIsSuspended);
2119   }
2120 }
2121 
2122 int os::signal_lookup() {
2123   return check_pending_signals(false);
2124 }
2125 
2126 int os::signal_wait() {
2127   return check_pending_signals(true);
2128 }
2129 
2130 ////////////////////////////////////////////////////////////////////////////////
2131 // Virtual Memory
2132 
2133 int os::vm_page_size() {
2134   // Seems redundant as all get out
2135   assert(os::Bsd::page_size() != -1, "must call os::init");
2136   return os::Bsd::page_size();
2137 }
2138 
2139 // Solaris allocates memory by pages.
2140 int os::vm_allocation_granularity() {
2141   assert(os::Bsd::page_size() != -1, "must call os::init");
2142   return os::Bsd::page_size();
2143 }
2144 
2145 // Rationale behind this function:
2146 //  current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2147 //  mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2148 //  samples for JITted code. Here we create private executable mapping over the code cache
2149 //  and then we can use standard (well, almost, as mapping can change) way to provide
2150 //  info for the reporting script by storing timestamp and location of symbol
2151 void bsd_wrap_code(char* base, size_t size) {
2152   static volatile jint cnt = 0;
2153 
2154   if (!UseOprofile) {
2155     return;
2156   }
2157 
2158   char buf[PATH_MAX + 1];
2159   int num = Atomic::add(1, &cnt);
2160 
2161   snprintf(buf, PATH_MAX + 1, "%s/hs-vm-%d-%d",
2162            os::get_temp_directory(), os::current_process_id(), num);
2163   unlink(buf);
2164 
2165   int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2166 
2167   if (fd != -1) {
2168     off_t rv = ::lseek(fd, size-2, SEEK_SET);
2169     if (rv != (off_t)-1) {
2170       if (::write(fd, "", 1) == 1) {
2171         mmap(base, size,
2172              PROT_READ|PROT_WRITE|PROT_EXEC,
2173              MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2174       }
2175     }
2176     ::close(fd);
2177     unlink(buf);
2178   }
2179 }
2180 
2181 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2182                                     int err) {
2183   warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2184           ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2185           strerror(err), err);
2186 }
2187 
2188 // NOTE: Bsd kernel does not really reserve the pages for us.
2189 //       All it does is to check if there are enough free pages
2190 //       left at the time of mmap(). This could be a potential
2191 //       problem.
2192 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2193   int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2194 #ifdef __OpenBSD__
2195   // XXX: Work-around mmap/MAP_FIXED bug temporarily on OpenBSD
2196   if (::mprotect(addr, size, prot) == 0) {
2197     return true;
2198   }
2199 #else
2200   uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2201                                      MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2202   if (res != (uintptr_t) MAP_FAILED) {
2203     return true;
2204   }
2205 #endif
2206 
2207   // Warn about any commit errors we see in non-product builds just
2208   // in case mmap() doesn't work as described on the man page.
2209   NOT_PRODUCT(warn_fail_commit_memory(addr, size, exec, errno);)
2210 
2211   return false;
2212 }
2213 
2214 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2215                           bool exec) {
2216   // alignment_hint is ignored on this OS
2217   return pd_commit_memory(addr, size, exec);
2218 }
2219 
2220 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2221                                   const char* mesg) {
2222   assert(mesg != NULL, "mesg must be specified");
2223   if (!pd_commit_memory(addr, size, exec)) {
2224     // add extra info in product mode for vm_exit_out_of_memory():
2225     PRODUCT_ONLY(warn_fail_commit_memory(addr, size, exec, errno);)
2226     vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2227   }
2228 }
2229 
2230 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2231                                   size_t alignment_hint, bool exec,
2232                                   const char* mesg) {
2233   // alignment_hint is ignored on this OS
2234   pd_commit_memory_or_exit(addr, size, exec, mesg);
2235 }
2236 
2237 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2238 }
2239 
2240 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2241   ::madvise(addr, bytes, MADV_DONTNEED);
2242 }
2243 
2244 void os::numa_make_global(char *addr, size_t bytes) {
2245 }
2246 
2247 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2248 }
2249 
2250 bool os::numa_topology_changed()   { return false; }
2251 
2252 size_t os::numa_get_groups_num() {
2253   return 1;
2254 }
2255 
2256 int os::numa_get_group_id() {
2257   return 0;
2258 }
2259 
2260 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2261   if (size > 0) {
2262     ids[0] = 0;
2263     return 1;
2264   }
2265   return 0;
2266 }
2267 
2268 bool os::get_page_info(char *start, page_info* info) {
2269   return false;
2270 }
2271 
2272 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2273   return end;
2274 }
2275 
2276 
2277 bool os::pd_uncommit_memory(char* addr, size_t size) {
2278 #ifdef __OpenBSD__
2279   // XXX: Work-around mmap/MAP_FIXED bug temporarily on OpenBSD
2280   return ::mprotect(addr, size, PROT_NONE) == 0;
2281 #else
2282   uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2283                                      MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2284   return res  != (uintptr_t) MAP_FAILED;
2285 #endif
2286 }
2287 
2288 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2289   return os::commit_memory(addr, size, !ExecMem);
2290 }
2291 
2292 // If this is a growable mapping, remove the guard pages entirely by
2293 // munmap()ping them.  If not, just call uncommit_memory().
2294 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2295   return os::uncommit_memory(addr, size);
2296 }
2297 
2298 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2299 // at 'requested_addr'. If there are existing memory mappings at the same
2300 // location, however, they will be overwritten. If 'fixed' is false,
2301 // 'requested_addr' is only treated as a hint, the return value may or
2302 // may not start from the requested address. Unlike Bsd mmap(), this
2303 // function returns NULL to indicate failure.
2304 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2305   char * addr;
2306   int flags;
2307 
2308   flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2309   if (fixed) {
2310     assert((uintptr_t)requested_addr % os::Bsd::page_size() == 0, "unaligned address");
2311     flags |= MAP_FIXED;
2312   }
2313 
2314   // Map reserved/uncommitted pages PROT_NONE so we fail early if we
2315   // touch an uncommitted page. Otherwise, the read/write might
2316   // succeed if we have enough swap space to back the physical page.
2317   addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
2318                        flags, -1, 0);
2319 
2320   return addr == MAP_FAILED ? NULL : addr;
2321 }
2322 
2323 static int anon_munmap(char * addr, size_t size) {
2324   return ::munmap(addr, size) == 0;
2325 }
2326 
2327 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
2328                             size_t alignment_hint) {
2329   return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2330 }
2331 
2332 bool os::pd_release_memory(char* addr, size_t size) {
2333   return anon_munmap(addr, size);
2334 }
2335 
2336 static bool bsd_mprotect(char* addr, size_t size, int prot) {
2337   // Bsd wants the mprotect address argument to be page aligned.
2338   char* bottom = (char*)align_size_down((intptr_t)addr, os::Bsd::page_size());
2339 
2340   // According to SUSv3, mprotect() should only be used with mappings
2341   // established by mmap(), and mmap() always maps whole pages. Unaligned
2342   // 'addr' likely indicates problem in the VM (e.g. trying to change
2343   // protection of malloc'ed or statically allocated memory). Check the
2344   // caller if you hit this assert.
2345   assert(addr == bottom, "sanity check");
2346 
2347   size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Bsd::page_size());
2348   return ::mprotect(bottom, size, prot) == 0;
2349 }
2350 
2351 // Set protections specified
2352 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2353                         bool is_committed) {
2354   unsigned int p = 0;
2355   switch (prot) {
2356   case MEM_PROT_NONE: p = PROT_NONE; break;
2357   case MEM_PROT_READ: p = PROT_READ; break;
2358   case MEM_PROT_RW:   p = PROT_READ|PROT_WRITE; break;
2359   case MEM_PROT_RWX:  p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2360   default:
2361     ShouldNotReachHere();
2362   }
2363   // is_committed is unused.
2364   return bsd_mprotect(addr, bytes, p);
2365 }
2366 
2367 bool os::guard_memory(char* addr, size_t size) {
2368   return bsd_mprotect(addr, size, PROT_NONE);
2369 }
2370 
2371 bool os::unguard_memory(char* addr, size_t size) {
2372   return bsd_mprotect(addr, size, PROT_READ|PROT_WRITE);
2373 }
2374 
2375 bool os::Bsd::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2376   return false;
2377 }
2378 
2379 // Large page support
2380 
2381 static size_t _large_page_size = 0;
2382 
2383 void os::large_page_init() {
2384 }
2385 
2386 
2387 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
2388   fatal("This code is not used or maintained.");
2389 
2390   // "exec" is passed in but not used.  Creating the shared image for
2391   // the code cache doesn't have an SHM_X executable permission to check.
2392   assert(UseLargePages && UseSHM, "only for SHM large pages");
2393 
2394   key_t key = IPC_PRIVATE;
2395   char *addr;
2396 
2397   bool warn_on_failure = UseLargePages &&
2398                          (!FLAG_IS_DEFAULT(UseLargePages) ||
2399                           !FLAG_IS_DEFAULT(LargePageSizeInBytes));
2400 
2401   // Create a large shared memory region to attach to based on size.
2402   // Currently, size is the total size of the heap
2403   int shmid = shmget(key, bytes, IPC_CREAT|SHM_R|SHM_W);
2404   if (shmid == -1) {
2405     // Possible reasons for shmget failure:
2406     // 1. shmmax is too small for Java heap.
2407     //    > check shmmax value: cat /proc/sys/kernel/shmmax
2408     //    > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
2409     // 2. not enough large page memory.
2410     //    > check available large pages: cat /proc/meminfo
2411     //    > increase amount of large pages:
2412     //          echo new_value > /proc/sys/vm/nr_hugepages
2413     //      Note 1: different Bsd may use different name for this property,
2414     //            e.g. on Redhat AS-3 it is "hugetlb_pool".
2415     //      Note 2: it's possible there's enough physical memory available but
2416     //            they are so fragmented after a long run that they can't
2417     //            coalesce into large pages. Try to reserve large pages when
2418     //            the system is still "fresh".
2419     if (warn_on_failure) {
2420       warning("Failed to reserve shared memory (errno = %d).", errno);
2421     }
2422     return NULL;
2423   }
2424 
2425   // attach to the region
2426   addr = (char*)shmat(shmid, req_addr, 0);
2427   int err = errno;
2428 
2429   // Remove shmid. If shmat() is successful, the actual shared memory segment
2430   // will be deleted when it's detached by shmdt() or when the process
2431   // terminates. If shmat() is not successful this will remove the shared
2432   // segment immediately.
2433   shmctl(shmid, IPC_RMID, NULL);
2434 
2435   if ((intptr_t)addr == -1) {
2436     if (warn_on_failure) {
2437       warning("Failed to attach shared memory (errno = %d).", err);
2438     }
2439     return NULL;
2440   }
2441 
2442   // The memory is committed
2443   MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
2444 
2445   return addr;
2446 }
2447 
2448 bool os::release_memory_special(char* base, size_t bytes) {
2449   if (MemTracker::tracking_level() > NMT_minimal) {
2450     Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
2451     // detaching the SHM segment will also delete it, see reserve_memory_special()
2452     int rslt = shmdt(base);
2453     if (rslt == 0) {
2454       tkr.record((address)base, bytes);
2455       return true;
2456     } else {
2457       return false;
2458     }
2459   } else {
2460     return shmdt(base) == 0;
2461   }
2462 }
2463 
2464 size_t os::large_page_size() {
2465   return _large_page_size;
2466 }
2467 
2468 // HugeTLBFS allows application to commit large page memory on demand;
2469 // with SysV SHM the entire memory region must be allocated as shared
2470 // memory.
2471 bool os::can_commit_large_page_memory() {
2472   return UseHugeTLBFS;
2473 }
2474 
2475 bool os::can_execute_large_page_memory() {
2476   return UseHugeTLBFS;
2477 }
2478 
2479 // Reserve memory at an arbitrary address, only if that area is
2480 // available (and not reserved for something else).
2481 
2482 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
2483   const int max_tries = 10;
2484   char* base[max_tries];
2485   size_t size[max_tries];
2486   const size_t gap = 0x000000;
2487 
2488   // Assert only that the size is a multiple of the page size, since
2489   // that's all that mmap requires, and since that's all we really know
2490   // about at this low abstraction level.  If we need higher alignment,
2491   // we can either pass an alignment to this method or verify alignment
2492   // in one of the methods further up the call chain.  See bug 5044738.
2493   assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
2494 
2495   // Repeatedly allocate blocks until the block is allocated at the
2496   // right spot.
2497 
2498   // Bsd mmap allows caller to pass an address as hint; give it a try first,
2499   // if kernel honors the hint then we can return immediately.
2500   char * addr = anon_mmap(requested_addr, bytes, false);
2501   if (addr == requested_addr) {
2502     return requested_addr;
2503   }
2504 
2505   if (addr != NULL) {
2506     // mmap() is successful but it fails to reserve at the requested address
2507     anon_munmap(addr, bytes);
2508   }
2509 
2510   int i;
2511   for (i = 0; i < max_tries; ++i) {
2512     base[i] = reserve_memory(bytes);
2513 
2514     if (base[i] != NULL) {
2515       // Is this the block we wanted?
2516       if (base[i] == requested_addr) {
2517         size[i] = bytes;
2518         break;
2519       }
2520 
2521       // Does this overlap the block we wanted? Give back the overlapped
2522       // parts and try again.
2523 
2524       size_t top_overlap = requested_addr + (bytes + gap) - base[i];
2525       if (top_overlap >= 0 && top_overlap < bytes) {
2526         unmap_memory(base[i], top_overlap);
2527         base[i] += top_overlap;
2528         size[i] = bytes - top_overlap;
2529       } else {
2530         size_t bottom_overlap = base[i] + bytes - requested_addr;
2531         if (bottom_overlap >= 0 && bottom_overlap < bytes) {
2532           unmap_memory(requested_addr, bottom_overlap);
2533           size[i] = bytes - bottom_overlap;
2534         } else {
2535           size[i] = bytes;
2536         }
2537       }
2538     }
2539   }
2540 
2541   // Give back the unused reserved pieces.
2542 
2543   for (int j = 0; j < i; ++j) {
2544     if (base[j] != NULL) {
2545       unmap_memory(base[j], size[j]);
2546     }
2547   }
2548 
2549   if (i < max_tries) {
2550     return requested_addr;
2551   } else {
2552     return NULL;
2553   }
2554 }
2555 
2556 size_t os::read(int fd, void *buf, unsigned int nBytes) {
2557   RESTARTABLE_RETURN_INT(::read(fd, buf, nBytes));
2558 }
2559 
2560 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
2561   RESTARTABLE_RETURN_INT(::pread(fd, buf, nBytes, offset));
2562 }
2563 
2564 void os::naked_short_sleep(jlong ms) {
2565   struct timespec req;
2566 
2567   assert(ms < 1000, "Un-interruptable sleep, short time use only");
2568   req.tv_sec = 0;
2569   if (ms > 0) {
2570     req.tv_nsec = (ms % 1000) * 1000000;
2571   } else {
2572     req.tv_nsec = 1;
2573   }
2574 
2575   nanosleep(&req, NULL);
2576 
2577   return;
2578 }
2579 
2580 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
2581 void os::infinite_sleep() {
2582   while (true) {    // sleep forever ...
2583     ::sleep(100);   // ... 100 seconds at a time
2584   }
2585 }
2586 
2587 // Used to convert frequent JVM_Yield() to nops
2588 bool os::dont_yield() {
2589   return DontYieldALot;
2590 }
2591 
2592 void os::naked_yield() {
2593   sched_yield();
2594 }
2595 
2596 ////////////////////////////////////////////////////////////////////////////////
2597 // thread priority support
2598 
2599 // Note: Normal Bsd applications are run with SCHED_OTHER policy. SCHED_OTHER
2600 // only supports dynamic priority, static priority must be zero. For real-time
2601 // applications, Bsd supports SCHED_RR which allows static priority (1-99).
2602 // However, for large multi-threaded applications, SCHED_RR is not only slower
2603 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
2604 // of 5 runs - Sep 2005).
2605 //
2606 // The following code actually changes the niceness of kernel-thread/LWP. It
2607 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
2608 // not the entire user process, and user level threads are 1:1 mapped to kernel
2609 // threads. It has always been the case, but could change in the future. For
2610 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
2611 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
2612 
2613 #if !defined(__APPLE__)
2614 int os::java_to_os_priority[CriticalPriority + 1] = {
2615   19,              // 0 Entry should never be used
2616 
2617    0,              // 1 MinPriority
2618    3,              // 2
2619    6,              // 3
2620 
2621   10,              // 4
2622   15,              // 5 NormPriority
2623   18,              // 6
2624 
2625   21,              // 7
2626   25,              // 8
2627   28,              // 9 NearMaxPriority
2628 
2629   31,              // 10 MaxPriority
2630 
2631   31               // 11 CriticalPriority
2632 };
2633 #else
2634 // Using Mach high-level priority assignments
2635 int os::java_to_os_priority[CriticalPriority + 1] = {
2636    0,              // 0 Entry should never be used (MINPRI_USER)
2637 
2638   27,              // 1 MinPriority
2639   28,              // 2
2640   29,              // 3
2641 
2642   30,              // 4
2643   31,              // 5 NormPriority (BASEPRI_DEFAULT)
2644   32,              // 6
2645 
2646   33,              // 7
2647   34,              // 8
2648   35,              // 9 NearMaxPriority
2649 
2650   36,              // 10 MaxPriority
2651 
2652   36               // 11 CriticalPriority
2653 };
2654 #endif
2655 
2656 static int prio_init() {
2657   if (ThreadPriorityPolicy == 1) {
2658     // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
2659     // if effective uid is not root. Perhaps, a more elegant way of doing
2660     // this is to test CAP_SYS_NICE capability, but that will require libcap.so
2661     if (geteuid() != 0) {
2662       if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
2663         warning("-XX:ThreadPriorityPolicy requires root privilege on Bsd");
2664       }
2665       ThreadPriorityPolicy = 0;
2666     }
2667   }
2668   if (UseCriticalJavaThreadPriority) {
2669     os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
2670   }
2671   return 0;
2672 }
2673 
2674 OSReturn os::set_native_priority(Thread* thread, int newpri) {
2675   if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
2676 
2677 #ifdef __OpenBSD__
2678   // OpenBSD pthread_setprio starves low priority threads
2679   return OS_OK;
2680 #elif defined(__FreeBSD__)
2681   int ret = pthread_setprio(thread->osthread()->pthread_id(), newpri);
2682 #elif defined(__APPLE__) || defined(__NetBSD__)
2683   struct sched_param sp;
2684   int policy;
2685   pthread_t self = pthread_self();
2686 
2687   if (pthread_getschedparam(self, &policy, &sp) != 0) {
2688     return OS_ERR;
2689   }
2690 
2691   sp.sched_priority = newpri;
2692   if (pthread_setschedparam(self, policy, &sp) != 0) {
2693     return OS_ERR;
2694   }
2695 
2696   return OS_OK;
2697 #else
2698   int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
2699   return (ret == 0) ? OS_OK : OS_ERR;
2700 #endif
2701 }
2702 
2703 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
2704   if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
2705     *priority_ptr = java_to_os_priority[NormPriority];
2706     return OS_OK;
2707   }
2708 
2709   errno = 0;
2710 #if defined(__OpenBSD__) || defined(__FreeBSD__)
2711   *priority_ptr = pthread_getprio(thread->osthread()->pthread_id());
2712 #elif defined(__APPLE__) || defined(__NetBSD__)
2713   int policy;
2714   struct sched_param sp;
2715 
2716   pthread_getschedparam(pthread_self(), &policy, &sp);
2717   *priority_ptr = sp.sched_priority;
2718 #else
2719   *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
2720 #endif
2721   return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
2722 }
2723 
2724 // Hint to the underlying OS that a task switch would not be good.
2725 // Void return because it's a hint and can fail.
2726 void os::hint_no_preempt() {}
2727 
2728 ////////////////////////////////////////////////////////////////////////////////
2729 // suspend/resume support
2730 
2731 //  the low-level signal-based suspend/resume support is a remnant from the
2732 //  old VM-suspension that used to be for java-suspension, safepoints etc,
2733 //  within hotspot. Now there is a single use-case for this:
2734 //    - calling get_thread_pc() on the VMThread by the flat-profiler task
2735 //      that runs in the watcher thread.
2736 //  The remaining code is greatly simplified from the more general suspension
2737 //  code that used to be used.
2738 //
2739 //  The protocol is quite simple:
2740 //  - suspend:
2741 //      - sends a signal to the target thread
2742 //      - polls the suspend state of the osthread using a yield loop
2743 //      - target thread signal handler (SR_handler) sets suspend state
2744 //        and blocks in sigsuspend until continued
2745 //  - resume:
2746 //      - sets target osthread state to continue
2747 //      - sends signal to end the sigsuspend loop in the SR_handler
2748 //
2749 //  Note that the SR_lock plays no role in this suspend/resume protocol.
2750 
2751 static void resume_clear_context(OSThread *osthread) {
2752   osthread->set_ucontext(NULL);
2753   osthread->set_siginfo(NULL);
2754 }
2755 
2756 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
2757   osthread->set_ucontext(context);
2758   osthread->set_siginfo(siginfo);
2759 }
2760 
2761 // Handler function invoked when a thread's execution is suspended or
2762 // resumed. We have to be careful that only async-safe functions are
2763 // called here (Note: most pthread functions are not async safe and
2764 // should be avoided.)
2765 //
2766 // Note: sigwait() is a more natural fit than sigsuspend() from an
2767 // interface point of view, but sigwait() prevents the signal hander
2768 // from being run. libpthread would get very confused by not having
2769 // its signal handlers run and prevents sigwait()'s use with the
2770 // mutex granting granting signal.
2771 //
2772 // Currently only ever called on the VMThread or JavaThread
2773 //
2774 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
2775   // Save and restore errno to avoid confusing native code with EINTR
2776   // after sigsuspend.
2777   int old_errno = errno;
2778 
2779   Thread* thread = Thread::current();
2780   OSThread* osthread = thread->osthread();
2781   assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
2782 
2783   os::SuspendResume::State current = osthread->sr.state();
2784   if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
2785     suspend_save_context(osthread, siginfo, context);
2786 
2787     // attempt to switch the state, we assume we had a SUSPEND_REQUEST
2788     os::SuspendResume::State state = osthread->sr.suspended();
2789     if (state == os::SuspendResume::SR_SUSPENDED) {
2790       sigset_t suspend_set;  // signals for sigsuspend()
2791 
2792       // get current set of blocked signals and unblock resume signal
2793       pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
2794       sigdelset(&suspend_set, SR_signum);
2795 
2796       sr_semaphore.signal();
2797       // wait here until we are resumed
2798       while (1) {
2799         sigsuspend(&suspend_set);
2800 
2801         os::SuspendResume::State result = osthread->sr.running();
2802         if (result == os::SuspendResume::SR_RUNNING) {
2803           sr_semaphore.signal();
2804           break;
2805         } else if (result != os::SuspendResume::SR_SUSPENDED) {
2806           ShouldNotReachHere();
2807         }
2808       }
2809 
2810     } else if (state == os::SuspendResume::SR_RUNNING) {
2811       // request was cancelled, continue
2812     } else {
2813       ShouldNotReachHere();
2814     }
2815 
2816     resume_clear_context(osthread);
2817   } else if (current == os::SuspendResume::SR_RUNNING) {
2818     // request was cancelled, continue
2819   } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
2820     // ignore
2821   } else {
2822     // ignore
2823   }
2824 
2825   errno = old_errno;
2826 }
2827 
2828 
2829 static int SR_initialize() {
2830   struct sigaction act;
2831   char *s;
2832   // Get signal number to use for suspend/resume
2833   if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
2834     int sig = ::strtol(s, 0, 10);
2835     if (sig > 0 || sig < NSIG) {
2836       SR_signum = sig;
2837     }
2838   }
2839 
2840   assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
2841          "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
2842 
2843   sigemptyset(&SR_sigset);
2844   sigaddset(&SR_sigset, SR_signum);
2845 
2846   // Set up signal handler for suspend/resume
2847   act.sa_flags = SA_RESTART|SA_SIGINFO;
2848   act.sa_handler = (void (*)(int)) SR_handler;
2849 
2850   // SR_signum is blocked by default.
2851   // 4528190 - We also need to block pthread restart signal (32 on all
2852   // supported Bsd platforms). Note that BsdThreads need to block
2853   // this signal for all threads to work properly. So we don't have
2854   // to use hard-coded signal number when setting up the mask.
2855   pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
2856 
2857   if (sigaction(SR_signum, &act, 0) == -1) {
2858     return -1;
2859   }
2860 
2861   // Save signal flag
2862   os::Bsd::set_our_sigflags(SR_signum, act.sa_flags);
2863   return 0;
2864 }
2865 
2866 static int sr_notify(OSThread* osthread) {
2867   int status = pthread_kill(osthread->pthread_id(), SR_signum);
2868   assert_status(status == 0, status, "pthread_kill");
2869   return status;
2870 }
2871 
2872 // "Randomly" selected value for how long we want to spin
2873 // before bailing out on suspending a thread, also how often
2874 // we send a signal to a thread we want to resume
2875 static const int RANDOMLY_LARGE_INTEGER = 1000000;
2876 static const int RANDOMLY_LARGE_INTEGER2 = 100;
2877 
2878 // returns true on success and false on error - really an error is fatal
2879 // but this seems the normal response to library errors
2880 static bool do_suspend(OSThread* osthread) {
2881   assert(osthread->sr.is_running(), "thread should be running");
2882   assert(!sr_semaphore.trywait(), "semaphore has invalid state");
2883 
2884   // mark as suspended and send signal
2885   if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
2886     // failed to switch, state wasn't running?
2887     ShouldNotReachHere();
2888     return false;
2889   }
2890 
2891   if (sr_notify(osthread) != 0) {
2892     ShouldNotReachHere();
2893   }
2894 
2895   // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
2896   while (true) {
2897     if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
2898       break;
2899     } else {
2900       // timeout
2901       os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
2902       if (cancelled == os::SuspendResume::SR_RUNNING) {
2903         return false;
2904       } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
2905         // make sure that we consume the signal on the semaphore as well
2906         sr_semaphore.wait();
2907         break;
2908       } else {
2909         ShouldNotReachHere();
2910         return false;
2911       }
2912     }
2913   }
2914 
2915   guarantee(osthread->sr.is_suspended(), "Must be suspended");
2916   return true;
2917 }
2918 
2919 static void do_resume(OSThread* osthread) {
2920   assert(osthread->sr.is_suspended(), "thread should be suspended");
2921   assert(!sr_semaphore.trywait(), "invalid semaphore state");
2922 
2923   if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
2924     // failed to switch to WAKEUP_REQUEST
2925     ShouldNotReachHere();
2926     return;
2927   }
2928 
2929   while (true) {
2930     if (sr_notify(osthread) == 0) {
2931       if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
2932         if (osthread->sr.is_running()) {
2933           return;
2934         }
2935       }
2936     } else {
2937       ShouldNotReachHere();
2938     }
2939   }
2940 
2941   guarantee(osthread->sr.is_running(), "Must be running!");
2942 }
2943 
2944 ///////////////////////////////////////////////////////////////////////////////////
2945 // signal handling (except suspend/resume)
2946 
2947 // This routine may be used by user applications as a "hook" to catch signals.
2948 // The user-defined signal handler must pass unrecognized signals to this
2949 // routine, and if it returns true (non-zero), then the signal handler must
2950 // return immediately.  If the flag "abort_if_unrecognized" is true, then this
2951 // routine will never retun false (zero), but instead will execute a VM panic
2952 // routine kill the process.
2953 //
2954 // If this routine returns false, it is OK to call it again.  This allows
2955 // the user-defined signal handler to perform checks either before or after
2956 // the VM performs its own checks.  Naturally, the user code would be making
2957 // a serious error if it tried to handle an exception (such as a null check
2958 // or breakpoint) that the VM was generating for its own correct operation.
2959 //
2960 // This routine may recognize any of the following kinds of signals:
2961 //    SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
2962 // It should be consulted by handlers for any of those signals.
2963 //
2964 // The caller of this routine must pass in the three arguments supplied
2965 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
2966 // field of the structure passed to sigaction().  This routine assumes that
2967 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
2968 //
2969 // Note that the VM will print warnings if it detects conflicting signal
2970 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
2971 //
2972 extern "C" JNIEXPORT int JVM_handle_bsd_signal(int signo, siginfo_t* siginfo,
2973                                                void* ucontext,
2974                                                int abort_if_unrecognized);
2975 
2976 void signalHandler(int sig, siginfo_t* info, void* uc) {
2977   assert(info != NULL && uc != NULL, "it must be old kernel");
2978   int orig_errno = errno;  // Preserve errno value over signal handler.
2979   JVM_handle_bsd_signal(sig, info, uc, true);
2980   errno = orig_errno;
2981 }
2982 
2983 
2984 // This boolean allows users to forward their own non-matching signals
2985 // to JVM_handle_bsd_signal, harmlessly.
2986 bool os::Bsd::signal_handlers_are_installed = false;
2987 
2988 // For signal-chaining
2989 struct sigaction os::Bsd::sigact[MAXSIGNUM];
2990 unsigned int os::Bsd::sigs = 0;
2991 bool os::Bsd::libjsig_is_loaded = false;
2992 typedef struct sigaction *(*get_signal_t)(int);
2993 get_signal_t os::Bsd::get_signal_action = NULL;
2994 
2995 struct sigaction* os::Bsd::get_chained_signal_action(int sig) {
2996   struct sigaction *actp = NULL;
2997 
2998   if (libjsig_is_loaded) {
2999     // Retrieve the old signal handler from libjsig
3000     actp = (*get_signal_action)(sig);
3001   }
3002   if (actp == NULL) {
3003     // Retrieve the preinstalled signal handler from jvm
3004     actp = get_preinstalled_handler(sig);
3005   }
3006 
3007   return actp;
3008 }
3009 
3010 static bool call_chained_handler(struct sigaction *actp, int sig,
3011                                  siginfo_t *siginfo, void *context) {
3012   // Call the old signal handler
3013   if (actp->sa_handler == SIG_DFL) {
3014     // It's more reasonable to let jvm treat it as an unexpected exception
3015     // instead of taking the default action.
3016     return false;
3017   } else if (actp->sa_handler != SIG_IGN) {
3018     if ((actp->sa_flags & SA_NODEFER) == 0) {
3019       // automaticlly block the signal
3020       sigaddset(&(actp->sa_mask), sig);
3021     }
3022 
3023     sa_handler_t hand;
3024     sa_sigaction_t sa;
3025     bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3026     // retrieve the chained handler
3027     if (siginfo_flag_set) {
3028       sa = actp->sa_sigaction;
3029     } else {
3030       hand = actp->sa_handler;
3031     }
3032 
3033     if ((actp->sa_flags & SA_RESETHAND) != 0) {
3034       actp->sa_handler = SIG_DFL;
3035     }
3036 
3037     // try to honor the signal mask
3038     sigset_t oset;
3039     pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3040 
3041     // call into the chained handler
3042     if (siginfo_flag_set) {
3043       (*sa)(sig, siginfo, context);
3044     } else {
3045       (*hand)(sig);
3046     }
3047 
3048     // restore the signal mask
3049     pthread_sigmask(SIG_SETMASK, &oset, 0);
3050   }
3051   // Tell jvm's signal handler the signal is taken care of.
3052   return true;
3053 }
3054 
3055 bool os::Bsd::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3056   bool chained = false;
3057   // signal-chaining
3058   if (UseSignalChaining) {
3059     struct sigaction *actp = get_chained_signal_action(sig);
3060     if (actp != NULL) {
3061       chained = call_chained_handler(actp, sig, siginfo, context);
3062     }
3063   }
3064   return chained;
3065 }
3066 
3067 struct sigaction* os::Bsd::get_preinstalled_handler(int sig) {
3068   if ((((unsigned int)1 << sig) & sigs) != 0) {
3069     return &sigact[sig];
3070   }
3071   return NULL;
3072 }
3073 
3074 void os::Bsd::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3075   assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3076   sigact[sig] = oldAct;
3077   sigs |= (unsigned int)1 << sig;
3078 }
3079 
3080 // for diagnostic
3081 int os::Bsd::sigflags[MAXSIGNUM];
3082 
3083 int os::Bsd::get_our_sigflags(int sig) {
3084   assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3085   return sigflags[sig];
3086 }
3087 
3088 void os::Bsd::set_our_sigflags(int sig, int flags) {
3089   assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3090   sigflags[sig] = flags;
3091 }
3092 
3093 void os::Bsd::set_signal_handler(int sig, bool set_installed) {
3094   // Check for overwrite.
3095   struct sigaction oldAct;
3096   sigaction(sig, (struct sigaction*)NULL, &oldAct);
3097 
3098   void* oldhand = oldAct.sa_sigaction
3099                 ? CAST_FROM_FN_PTR(void*,  oldAct.sa_sigaction)
3100                 : CAST_FROM_FN_PTR(void*,  oldAct.sa_handler);
3101   if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3102       oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3103       oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3104     if (AllowUserSignalHandlers || !set_installed) {
3105       // Do not overwrite; user takes responsibility to forward to us.
3106       return;
3107     } else if (UseSignalChaining) {
3108       // save the old handler in jvm
3109       save_preinstalled_handler(sig, oldAct);
3110       // libjsig also interposes the sigaction() call below and saves the
3111       // old sigaction on it own.
3112     } else {
3113       fatal("Encountered unexpected pre-existing sigaction handler "
3114             "%#lx for signal %d.", (long)oldhand, sig);
3115     }
3116   }
3117 
3118   struct sigaction sigAct;
3119   sigfillset(&(sigAct.sa_mask));
3120   sigAct.sa_handler = SIG_DFL;
3121   if (!set_installed) {
3122     sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3123   } else {
3124     sigAct.sa_sigaction = signalHandler;
3125     sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3126   }
3127 #ifdef __APPLE__
3128   // Needed for main thread as XNU (Mac OS X kernel) will only deliver SIGSEGV
3129   // (which starts as SIGBUS) on main thread with faulting address inside "stack+guard pages"
3130   // if the signal handler declares it will handle it on alternate stack.
3131   // Notice we only declare we will handle it on alt stack, but we are not
3132   // actually going to use real alt stack - this is just a workaround.
3133   // Please see ux_exception.c, method catch_mach_exception_raise for details
3134   // link http://www.opensource.apple.com/source/xnu/xnu-2050.18.24/bsd/uxkern/ux_exception.c
3135   if (sig == SIGSEGV) {
3136     sigAct.sa_flags |= SA_ONSTACK;
3137   }
3138 #endif
3139 
3140   // Save flags, which are set by ours
3141   assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3142   sigflags[sig] = sigAct.sa_flags;
3143 
3144   int ret = sigaction(sig, &sigAct, &oldAct);
3145   assert(ret == 0, "check");
3146 
3147   void* oldhand2  = oldAct.sa_sigaction
3148                   ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3149                   : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3150   assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3151 }
3152 
3153 // install signal handlers for signals that HotSpot needs to
3154 // handle in order to support Java-level exception handling.
3155 
3156 void os::Bsd::install_signal_handlers() {
3157   if (!signal_handlers_are_installed) {
3158     signal_handlers_are_installed = true;
3159 
3160     // signal-chaining
3161     typedef void (*signal_setting_t)();
3162     signal_setting_t begin_signal_setting = NULL;
3163     signal_setting_t end_signal_setting = NULL;
3164     begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3165                                           dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3166     if (begin_signal_setting != NULL) {
3167       end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3168                                           dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3169       get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3170                                          dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3171       libjsig_is_loaded = true;
3172       assert(UseSignalChaining, "should enable signal-chaining");
3173     }
3174     if (libjsig_is_loaded) {
3175       // Tell libjsig jvm is setting signal handlers
3176       (*begin_signal_setting)();
3177     }
3178 
3179     set_signal_handler(SIGSEGV, true);
3180     set_signal_handler(SIGPIPE, true);
3181     set_signal_handler(SIGBUS, true);
3182     set_signal_handler(SIGILL, true);
3183     set_signal_handler(SIGFPE, true);
3184     set_signal_handler(SIGXFSZ, true);
3185 
3186 #if defined(__APPLE__)
3187     // In Mac OS X 10.4, CrashReporter will write a crash log for all 'fatal' signals, including
3188     // signals caught and handled by the JVM. To work around this, we reset the mach task
3189     // signal handler that's placed on our process by CrashReporter. This disables
3190     // CrashReporter-based reporting.
3191     //
3192     // This work-around is not necessary for 10.5+, as CrashReporter no longer intercedes
3193     // on caught fatal signals.
3194     //
3195     // Additionally, gdb installs both standard BSD signal handlers, and mach exception
3196     // handlers. By replacing the existing task exception handler, we disable gdb's mach
3197     // exception handling, while leaving the standard BSD signal handlers functional.
3198     kern_return_t kr;
3199     kr = task_set_exception_ports(mach_task_self(),
3200                                   EXC_MASK_BAD_ACCESS | EXC_MASK_ARITHMETIC,
3201                                   MACH_PORT_NULL,
3202                                   EXCEPTION_STATE_IDENTITY,
3203                                   MACHINE_THREAD_STATE);
3204 
3205     assert(kr == KERN_SUCCESS, "could not set mach task signal handler");
3206 #endif
3207 
3208     if (libjsig_is_loaded) {
3209       // Tell libjsig jvm finishes setting signal handlers
3210       (*end_signal_setting)();
3211     }
3212 
3213     // We don't activate signal checker if libjsig is in place, we trust ourselves
3214     // and if UserSignalHandler is installed all bets are off
3215     if (CheckJNICalls) {
3216       if (libjsig_is_loaded) {
3217         if (PrintJNIResolving) {
3218           tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3219         }
3220         check_signals = false;
3221       }
3222       if (AllowUserSignalHandlers) {
3223         if (PrintJNIResolving) {
3224           tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3225         }
3226         check_signals = false;
3227       }
3228     }
3229   }
3230 }
3231 
3232 
3233 /////
3234 // glibc on Bsd platform uses non-documented flag
3235 // to indicate, that some special sort of signal
3236 // trampoline is used.
3237 // We will never set this flag, and we should
3238 // ignore this flag in our diagnostic
3239 #ifdef SIGNIFICANT_SIGNAL_MASK
3240   #undef SIGNIFICANT_SIGNAL_MASK
3241 #endif
3242 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3243 
3244 static const char* get_signal_handler_name(address handler,
3245                                            char* buf, int buflen) {
3246   int offset;
3247   bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3248   if (found) {
3249     // skip directory names
3250     const char *p1, *p2;
3251     p1 = buf;
3252     size_t len = strlen(os::file_separator());
3253     while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3254     jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3255   } else {
3256     jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3257   }
3258   return buf;
3259 }
3260 
3261 static void print_signal_handler(outputStream* st, int sig,
3262                                  char* buf, size_t buflen) {
3263   struct sigaction sa;
3264 
3265   sigaction(sig, NULL, &sa);
3266 
3267   // See comment for SIGNIFICANT_SIGNAL_MASK define
3268   sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3269 
3270   st->print("%s: ", os::exception_name(sig, buf, buflen));
3271 
3272   address handler = (sa.sa_flags & SA_SIGINFO)
3273     ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3274     : CAST_FROM_FN_PTR(address, sa.sa_handler);
3275 
3276   if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3277     st->print("SIG_DFL");
3278   } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3279     st->print("SIG_IGN");
3280   } else {
3281     st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3282   }
3283 
3284   st->print(", sa_mask[0]=");
3285   os::Posix::print_signal_set_short(st, &sa.sa_mask);
3286 
3287   address rh = VMError::get_resetted_sighandler(sig);
3288   // May be, handler was resetted by VMError?
3289   if (rh != NULL) {
3290     handler = rh;
3291     sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3292   }
3293 
3294   st->print(", sa_flags=");
3295   os::Posix::print_sa_flags(st, sa.sa_flags);
3296 
3297   // Check: is it our handler?
3298   if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3299       handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3300     // It is our signal handler
3301     // check for flags, reset system-used one!
3302     if ((int)sa.sa_flags != os::Bsd::get_our_sigflags(sig)) {
3303       st->print(
3304                 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3305                 os::Bsd::get_our_sigflags(sig));
3306     }
3307   }
3308   st->cr();
3309 }
3310 
3311 
3312 #define DO_SIGNAL_CHECK(sig)                      \
3313   do {                                            \
3314     if (!sigismember(&check_signal_done, sig)) {  \
3315       os::Bsd::check_signal_handler(sig);         \
3316     }                                             \
3317   } while (0)
3318 
3319 // This method is a periodic task to check for misbehaving JNI applications
3320 // under CheckJNI, we can add any periodic checks here
3321 
3322 void os::run_periodic_checks() {
3323 
3324   if (check_signals == false) return;
3325 
3326   // SEGV and BUS if overridden could potentially prevent
3327   // generation of hs*.log in the event of a crash, debugging
3328   // such a case can be very challenging, so we absolutely
3329   // check the following for a good measure:
3330   DO_SIGNAL_CHECK(SIGSEGV);
3331   DO_SIGNAL_CHECK(SIGILL);
3332   DO_SIGNAL_CHECK(SIGFPE);
3333   DO_SIGNAL_CHECK(SIGBUS);
3334   DO_SIGNAL_CHECK(SIGPIPE);
3335   DO_SIGNAL_CHECK(SIGXFSZ);
3336 
3337 
3338   // ReduceSignalUsage allows the user to override these handlers
3339   // see comments at the very top and jvm_solaris.h
3340   if (!ReduceSignalUsage) {
3341     DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
3342     DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
3343     DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
3344     DO_SIGNAL_CHECK(BREAK_SIGNAL);
3345   }
3346 
3347   DO_SIGNAL_CHECK(SR_signum);
3348   DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
3349 }
3350 
3351 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
3352 
3353 static os_sigaction_t os_sigaction = NULL;
3354 
3355 void os::Bsd::check_signal_handler(int sig) {
3356   char buf[O_BUFLEN];
3357   address jvmHandler = NULL;
3358 
3359 
3360   struct sigaction act;
3361   if (os_sigaction == NULL) {
3362     // only trust the default sigaction, in case it has been interposed
3363     os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
3364     if (os_sigaction == NULL) return;
3365   }
3366 
3367   os_sigaction(sig, (struct sigaction*)NULL, &act);
3368 
3369 
3370   act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3371 
3372   address thisHandler = (act.sa_flags & SA_SIGINFO)
3373     ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
3374     : CAST_FROM_FN_PTR(address, act.sa_handler);
3375 
3376 
3377   switch (sig) {
3378   case SIGSEGV:
3379   case SIGBUS:
3380   case SIGFPE:
3381   case SIGPIPE:
3382   case SIGILL:
3383   case SIGXFSZ:
3384     jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
3385     break;
3386 
3387   case SHUTDOWN1_SIGNAL:
3388   case SHUTDOWN2_SIGNAL:
3389   case SHUTDOWN3_SIGNAL:
3390   case BREAK_SIGNAL:
3391     jvmHandler = (address)user_handler();
3392     break;
3393 
3394   case INTERRUPT_SIGNAL:
3395     jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
3396     break;
3397 
3398   default:
3399     if (sig == SR_signum) {
3400       jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
3401     } else {
3402       return;
3403     }
3404     break;
3405   }
3406 
3407   if (thisHandler != jvmHandler) {
3408     tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
3409     tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
3410     tty->print_cr("  found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
3411     // No need to check this sig any longer
3412     sigaddset(&check_signal_done, sig);
3413     // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
3414     if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
3415       tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
3416                     exception_name(sig, buf, O_BUFLEN));
3417     }
3418   } else if(os::Bsd::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Bsd::get_our_sigflags(sig)) {
3419     tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
3420     tty->print("expected:" PTR32_FORMAT, os::Bsd::get_our_sigflags(sig));
3421     tty->print_cr("  found:" PTR32_FORMAT, act.sa_flags);
3422     // No need to check this sig any longer
3423     sigaddset(&check_signal_done, sig);
3424   }
3425 
3426   // Dump all the signal
3427   if (sigismember(&check_signal_done, sig)) {
3428     print_signal_handlers(tty, buf, O_BUFLEN);
3429   }
3430 }
3431 
3432 extern void report_error(char* file_name, int line_no, char* title,
3433                          char* format, ...);
3434 
3435 extern bool signal_name(int signo, char* buf, size_t len);
3436 
3437 const char* os::exception_name(int exception_code, char* buf, size_t size) {
3438   if (0 < exception_code && exception_code <= SIGRTMAX) {
3439     // signal
3440     if (!signal_name(exception_code, buf, size)) {
3441       jio_snprintf(buf, size, "SIG%d", exception_code);
3442     }
3443     return buf;
3444   } else {
3445     return NULL;
3446   }
3447 }
3448 
3449 // this is called _before_ the most of global arguments have been parsed
3450 void os::init(void) {
3451   char dummy;   // used to get a guess on initial stack address
3452 //  first_hrtime = gethrtime();
3453 
3454   // With BsdThreads the JavaMain thread pid (primordial thread)
3455   // is different than the pid of the java launcher thread.
3456   // So, on Bsd, the launcher thread pid is passed to the VM
3457   // via the sun.java.launcher.pid property.
3458   // Use this property instead of getpid() if it was correctly passed.
3459   // See bug 6351349.
3460   pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
3461 
3462   _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
3463 
3464   clock_tics_per_sec = CLK_TCK;
3465 
3466   init_random(1234567);
3467 
3468   ThreadCritical::initialize();
3469 
3470   Bsd::set_page_size(getpagesize());
3471   if (Bsd::page_size() == -1) {
3472     fatal("os_bsd.cpp: os::init: sysconf failed (%s)", strerror(errno));
3473   }
3474   init_page_sizes((size_t) Bsd::page_size());
3475 
3476   Bsd::initialize_system_info();
3477 
3478   // main_thread points to the aboriginal thread
3479   Bsd::_main_thread = pthread_self();
3480 
3481   Bsd::clock_init();
3482   initial_time_count = javaTimeNanos();
3483 
3484 #ifdef __APPLE__
3485   // XXXDARWIN
3486   // Work around the unaligned VM callbacks in hotspot's
3487   // sharedRuntime. The callbacks don't use SSE2 instructions, and work on
3488   // Linux, Solaris, and FreeBSD. On Mac OS X, dyld (rightly so) enforces
3489   // alignment when doing symbol lookup. To work around this, we force early
3490   // binding of all symbols now, thus binding when alignment is known-good.
3491   _dyld_bind_fully_image_containing_address((const void *) &os::init);
3492 #endif
3493 }
3494 
3495 // To install functions for atexit system call
3496 extern "C" {
3497   static void perfMemory_exit_helper() {
3498     perfMemory_exit();
3499   }
3500 }
3501 
3502 // this is called _after_ the global arguments have been parsed
3503 jint os::init_2(void) {
3504   // Allocate a single page and mark it as readable for safepoint polling
3505   address polling_page = (address) ::mmap(NULL, Bsd::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
3506   guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page");
3507 
3508   os::set_polling_page(polling_page);
3509 
3510 #ifndef PRODUCT
3511   if (Verbose && PrintMiscellaneous) {
3512     tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n",
3513                (intptr_t)polling_page);
3514   }
3515 #endif
3516 
3517   if (!UseMembar) {
3518     address mem_serialize_page = (address) ::mmap(NULL, Bsd::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
3519     guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
3520     os::set_memory_serialize_page(mem_serialize_page);
3521 
3522 #ifndef PRODUCT
3523     if (Verbose && PrintMiscellaneous) {
3524       tty->print("[Memory Serialize  Page address: " INTPTR_FORMAT "]\n",
3525                  (intptr_t)mem_serialize_page);
3526     }
3527 #endif
3528   }
3529 
3530   // initialize suspend/resume support - must do this before signal_sets_init()
3531   if (SR_initialize() != 0) {
3532     perror("SR_initialize failed");
3533     return JNI_ERR;
3534   }
3535 
3536   Bsd::signal_sets_init();
3537   Bsd::install_signal_handlers();
3538 
3539   // Check minimum allowable stack size for thread creation and to initialize
3540   // the java system classes, including StackOverflowError - depends on page
3541   // size.  Add a page for compiler2 recursion in main thread.
3542   // Add in 2*BytesPerWord times page size to account for VM stack during
3543   // class initialization depending on 32 or 64 bit VM.
3544   os::Bsd::min_stack_allowed = MAX2(os::Bsd::min_stack_allowed,
3545                                     (size_t)(StackYellowPages+StackRedPages+StackShadowPages+
3546                                     2*BytesPerWord COMPILER2_PRESENT(+1)) * Bsd::page_size());
3547 
3548   size_t threadStackSizeInBytes = ThreadStackSize * K;
3549   if (threadStackSizeInBytes != 0 &&
3550       threadStackSizeInBytes < os::Bsd::min_stack_allowed) {
3551     tty->print_cr("\nThe stack size specified is too small, "
3552                   "Specify at least %dk",
3553                   os::Bsd::min_stack_allowed/ K);
3554     return JNI_ERR;
3555   }
3556 
3557   // Make the stack size a multiple of the page size so that
3558   // the yellow/red zones can be guarded.
3559   JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
3560                                                 vm_page_size()));
3561 
3562   if (MaxFDLimit) {
3563     // set the number of file descriptors to max. print out error
3564     // if getrlimit/setrlimit fails but continue regardless.
3565     struct rlimit nbr_files;
3566     int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
3567     if (status != 0) {
3568       if (PrintMiscellaneous && (Verbose || WizardMode)) {
3569         perror("os::init_2 getrlimit failed");
3570       }
3571     } else {
3572       nbr_files.rlim_cur = nbr_files.rlim_max;
3573 
3574 #ifdef __APPLE__
3575       // Darwin returns RLIM_INFINITY for rlim_max, but fails with EINVAL if
3576       // you attempt to use RLIM_INFINITY. As per setrlimit(2), OPEN_MAX must
3577       // be used instead
3578       nbr_files.rlim_cur = MIN(OPEN_MAX, nbr_files.rlim_cur);
3579 #endif
3580 
3581       status = setrlimit(RLIMIT_NOFILE, &nbr_files);
3582       if (status != 0) {
3583         if (PrintMiscellaneous && (Verbose || WizardMode)) {
3584           perror("os::init_2 setrlimit failed");
3585         }
3586       }
3587     }
3588   }
3589 
3590   // at-exit methods are called in the reverse order of their registration.
3591   // atexit functions are called on return from main or as a result of a
3592   // call to exit(3C). There can be only 32 of these functions registered
3593   // and atexit() does not set errno.
3594 
3595   if (PerfAllowAtExitRegistration) {
3596     // only register atexit functions if PerfAllowAtExitRegistration is set.
3597     // atexit functions can be delayed until process exit time, which
3598     // can be problematic for embedded VM situations. Embedded VMs should
3599     // call DestroyJavaVM() to assure that VM resources are released.
3600 
3601     // note: perfMemory_exit_helper atexit function may be removed in
3602     // the future if the appropriate cleanup code can be added to the
3603     // VM_Exit VMOperation's doit method.
3604     if (atexit(perfMemory_exit_helper) != 0) {
3605       warning("os::init2 atexit(perfMemory_exit_helper) failed");
3606     }
3607   }
3608 
3609   // initialize thread priority policy
3610   prio_init();
3611 
3612 #ifdef __APPLE__
3613   // dynamically link to objective c gc registration
3614   void *handleLibObjc = dlopen(OBJC_LIB, RTLD_LAZY);
3615   if (handleLibObjc != NULL) {
3616     objc_registerThreadWithCollectorFunction = (objc_registerThreadWithCollector_t) dlsym(handleLibObjc, OBJC_GCREGISTER);
3617   }
3618 #endif
3619 
3620   return JNI_OK;
3621 }
3622 
3623 // Mark the polling page as unreadable
3624 void os::make_polling_page_unreadable(void) {
3625   if (!guard_memory((char*)_polling_page, Bsd::page_size())) {
3626     fatal("Could not disable polling page");
3627   }
3628 }
3629 
3630 // Mark the polling page as readable
3631 void os::make_polling_page_readable(void) {
3632   if (!bsd_mprotect((char *)_polling_page, Bsd::page_size(), PROT_READ)) {
3633     fatal("Could not enable polling page");
3634   }
3635 }
3636 
3637 int os::active_processor_count() {
3638   return _processor_count;
3639 }
3640 
3641 void os::set_native_thread_name(const char *name) {
3642 #if defined(__APPLE__) && MAC_OS_X_VERSION_MIN_REQUIRED > MAC_OS_X_VERSION_10_5
3643   // This is only supported in Snow Leopard and beyond
3644   if (name != NULL) {
3645     // Add a "Java: " prefix to the name
3646     char buf[MAXTHREADNAMESIZE];
3647     snprintf(buf, sizeof(buf), "Java: %s", name);
3648     pthread_setname_np(buf);
3649   }
3650 #endif
3651 }
3652 
3653 bool os::distribute_processes(uint length, uint* distribution) {
3654   // Not yet implemented.
3655   return false;
3656 }
3657 
3658 bool os::bind_to_processor(uint processor_id) {
3659   // Not yet implemented.
3660   return false;
3661 }
3662 
3663 void os::SuspendedThreadTask::internal_do_task() {
3664   if (do_suspend(_thread->osthread())) {
3665     SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
3666     do_task(context);
3667     do_resume(_thread->osthread());
3668   }
3669 }
3670 
3671 ///
3672 class PcFetcher : public os::SuspendedThreadTask {
3673  public:
3674   PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
3675   ExtendedPC result();
3676  protected:
3677   void do_task(const os::SuspendedThreadTaskContext& context);
3678  private:
3679   ExtendedPC _epc;
3680 };
3681 
3682 ExtendedPC PcFetcher::result() {
3683   guarantee(is_done(), "task is not done yet.");
3684   return _epc;
3685 }
3686 
3687 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
3688   Thread* thread = context.thread();
3689   OSThread* osthread = thread->osthread();
3690   if (osthread->ucontext() != NULL) {
3691     _epc = os::Bsd::ucontext_get_pc((ucontext_t *) context.ucontext());
3692   } else {
3693     // NULL context is unexpected, double-check this is the VMThread
3694     guarantee(thread->is_VM_thread(), "can only be called for VMThread");
3695   }
3696 }
3697 
3698 // Suspends the target using the signal mechanism and then grabs the PC before
3699 // resuming the target. Used by the flat-profiler only
3700 ExtendedPC os::get_thread_pc(Thread* thread) {
3701   // Make sure that it is called by the watcher for the VMThread
3702   assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
3703   assert(thread->is_VM_thread(), "Can only be called for VMThread");
3704 
3705   PcFetcher fetcher(thread);
3706   fetcher.run();
3707   return fetcher.result();
3708 }
3709 
3710 ////////////////////////////////////////////////////////////////////////////////
3711 // debug support
3712 
3713 bool os::find(address addr, outputStream* st) {
3714   Dl_info dlinfo;
3715   memset(&dlinfo, 0, sizeof(dlinfo));
3716   if (dladdr(addr, &dlinfo) != 0) {
3717     st->print(PTR_FORMAT ": ", addr);
3718     if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
3719       st->print("%s+%#x", dlinfo.dli_sname,
3720                 addr - (intptr_t)dlinfo.dli_saddr);
3721     } else if (dlinfo.dli_fbase != NULL) {
3722       st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
3723     } else {
3724       st->print("<absolute address>");
3725     }
3726     if (dlinfo.dli_fname != NULL) {
3727       st->print(" in %s", dlinfo.dli_fname);
3728     }
3729     if (dlinfo.dli_fbase != NULL) {
3730       st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
3731     }
3732     st->cr();
3733 
3734     if (Verbose) {
3735       // decode some bytes around the PC
3736       address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
3737       address end   = clamp_address_in_page(addr+40, addr, os::vm_page_size());
3738       address       lowest = (address) dlinfo.dli_sname;
3739       if (!lowest)  lowest = (address) dlinfo.dli_fbase;
3740       if (begin < lowest)  begin = lowest;
3741       Dl_info dlinfo2;
3742       if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
3743           && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
3744         end = (address) dlinfo2.dli_saddr;
3745       }
3746       Disassembler::decode(begin, end, st);
3747     }
3748     return true;
3749   }
3750   return false;
3751 }
3752 
3753 ////////////////////////////////////////////////////////////////////////////////
3754 // misc
3755 
3756 // This does not do anything on Bsd. This is basically a hook for being
3757 // able to use structured exception handling (thread-local exception filters)
3758 // on, e.g., Win32.
3759 void os::os_exception_wrapper(java_call_t f, JavaValue* value,
3760                               methodHandle* method, JavaCallArguments* args,
3761                               Thread* thread) {
3762   f(value, method, args, thread);
3763 }
3764 
3765 void os::print_statistics() {
3766 }
3767 
3768 int os::message_box(const char* title, const char* message) {
3769   int i;
3770   fdStream err(defaultStream::error_fd());
3771   for (i = 0; i < 78; i++) err.print_raw("=");
3772   err.cr();
3773   err.print_raw_cr(title);
3774   for (i = 0; i < 78; i++) err.print_raw("-");
3775   err.cr();
3776   err.print_raw_cr(message);
3777   for (i = 0; i < 78; i++) err.print_raw("=");
3778   err.cr();
3779 
3780   char buf[16];
3781   // Prevent process from exiting upon "read error" without consuming all CPU
3782   while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
3783 
3784   return buf[0] == 'y' || buf[0] == 'Y';
3785 }
3786 
3787 int os::stat(const char *path, struct stat *sbuf) {
3788   char pathbuf[MAX_PATH];
3789   if (strlen(path) > MAX_PATH - 1) {
3790     errno = ENAMETOOLONG;
3791     return -1;
3792   }
3793   os::native_path(strcpy(pathbuf, path));
3794   return ::stat(pathbuf, sbuf);
3795 }
3796 
3797 bool os::check_heap(bool force) {
3798   return true;
3799 }
3800 
3801 // Is a (classpath) directory empty?
3802 bool os::dir_is_empty(const char* path) {
3803   DIR *dir = NULL;
3804   struct dirent *ptr;
3805 
3806   dir = opendir(path);
3807   if (dir == NULL) return true;
3808 
3809   // Scan the directory
3810   bool result = true;
3811   char buf[sizeof(struct dirent) + MAX_PATH];
3812   while (result && (ptr = ::readdir(dir)) != NULL) {
3813     if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
3814       result = false;
3815     }
3816   }
3817   closedir(dir);
3818   return result;
3819 }
3820 
3821 // This code originates from JDK's sysOpen and open64_w
3822 // from src/solaris/hpi/src/system_md.c
3823 
3824 int os::open(const char *path, int oflag, int mode) {
3825   if (strlen(path) > MAX_PATH - 1) {
3826     errno = ENAMETOOLONG;
3827     return -1;
3828   }
3829   int fd;
3830 
3831   fd = ::open(path, oflag, mode);
3832   if (fd == -1) return -1;
3833 
3834   // If the open succeeded, the file might still be a directory
3835   {
3836     struct stat buf;
3837     int ret = ::fstat(fd, &buf);
3838     int st_mode = buf.st_mode;
3839 
3840     if (ret != -1) {
3841       if ((st_mode & S_IFMT) == S_IFDIR) {
3842         errno = EISDIR;
3843         ::close(fd);
3844         return -1;
3845       }
3846     } else {
3847       ::close(fd);
3848       return -1;
3849     }
3850   }
3851 
3852   // All file descriptors that are opened in the JVM and not
3853   // specifically destined for a subprocess should have the
3854   // close-on-exec flag set.  If we don't set it, then careless 3rd
3855   // party native code might fork and exec without closing all
3856   // appropriate file descriptors (e.g. as we do in closeDescriptors in
3857   // UNIXProcess.c), and this in turn might:
3858   //
3859   // - cause end-of-file to fail to be detected on some file
3860   //   descriptors, resulting in mysterious hangs, or
3861   //
3862   // - might cause an fopen in the subprocess to fail on a system
3863   //   suffering from bug 1085341.
3864   //
3865   // (Yes, the default setting of the close-on-exec flag is a Unix
3866   // design flaw)
3867   //
3868   // See:
3869   // 1085341: 32-bit stdio routines should support file descriptors >255
3870   // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
3871   // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
3872   //
3873 #ifdef FD_CLOEXEC
3874   {
3875     int flags = ::fcntl(fd, F_GETFD);
3876     if (flags != -1) {
3877       ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
3878     }
3879   }
3880 #endif
3881 
3882   return fd;
3883 }
3884 
3885 
3886 // create binary file, rewriting existing file if required
3887 int os::create_binary_file(const char* path, bool rewrite_existing) {
3888   int oflags = O_WRONLY | O_CREAT;
3889   if (!rewrite_existing) {
3890     oflags |= O_EXCL;
3891   }
3892   return ::open(path, oflags, S_IREAD | S_IWRITE);
3893 }
3894 
3895 // return current position of file pointer
3896 jlong os::current_file_offset(int fd) {
3897   return (jlong)::lseek(fd, (off_t)0, SEEK_CUR);
3898 }
3899 
3900 // move file pointer to the specified offset
3901 jlong os::seek_to_file_offset(int fd, jlong offset) {
3902   return (jlong)::lseek(fd, (off_t)offset, SEEK_SET);
3903 }
3904 
3905 // This code originates from JDK's sysAvailable
3906 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
3907 
3908 int os::available(int fd, jlong *bytes) {
3909   jlong cur, end;
3910   int mode;
3911   struct stat buf;
3912 
3913   if (::fstat(fd, &buf) >= 0) {
3914     mode = buf.st_mode;
3915     if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
3916       // XXX: is the following call interruptible? If so, this might
3917       // need to go through the INTERRUPT_IO() wrapper as for other
3918       // blocking, interruptible calls in this file.
3919       int n;
3920       if (::ioctl(fd, FIONREAD, &n) >= 0) {
3921         *bytes = n;
3922         return 1;
3923       }
3924     }
3925   }
3926   if ((cur = ::lseek(fd, 0L, SEEK_CUR)) == -1) {
3927     return 0;
3928   } else if ((end = ::lseek(fd, 0L, SEEK_END)) == -1) {
3929     return 0;
3930   } else if (::lseek(fd, cur, SEEK_SET) == -1) {
3931     return 0;
3932   }
3933   *bytes = end - cur;
3934   return 1;
3935 }
3936 
3937 // Map a block of memory.
3938 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
3939                         char *addr, size_t bytes, bool read_only,
3940                         bool allow_exec) {
3941   int prot;
3942   int flags;
3943 
3944   if (read_only) {
3945     prot = PROT_READ;
3946     flags = MAP_SHARED;
3947   } else {
3948     prot = PROT_READ | PROT_WRITE;
3949     flags = MAP_PRIVATE;
3950   }
3951 
3952   if (allow_exec) {
3953     prot |= PROT_EXEC;
3954   }
3955 
3956   if (addr != NULL) {
3957     flags |= MAP_FIXED;
3958   }
3959 
3960   char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
3961                                      fd, file_offset);
3962   if (mapped_address == MAP_FAILED) {
3963     return NULL;
3964   }
3965   return mapped_address;
3966 }
3967 
3968 
3969 // Remap a block of memory.
3970 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
3971                           char *addr, size_t bytes, bool read_only,
3972                           bool allow_exec) {
3973   // same as map_memory() on this OS
3974   return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
3975                         allow_exec);
3976 }
3977 
3978 
3979 // Unmap a block of memory.
3980 bool os::pd_unmap_memory(char* addr, size_t bytes) {
3981   return munmap(addr, bytes) == 0;
3982 }
3983 
3984 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
3985 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
3986 // of a thread.
3987 //
3988 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
3989 // the fast estimate available on the platform.
3990 
3991 jlong os::current_thread_cpu_time() {
3992 #ifdef __APPLE__
3993   return os::thread_cpu_time(Thread::current(), true /* user + sys */);
3994 #else
3995   Unimplemented();
3996   return 0;
3997 #endif
3998 }
3999 
4000 jlong os::thread_cpu_time(Thread* thread) {
4001 #ifdef __APPLE__
4002   return os::thread_cpu_time(thread, true /* user + sys */);
4003 #else
4004   Unimplemented();
4005   return 0;
4006 #endif
4007 }
4008 
4009 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4010 #ifdef __APPLE__
4011   return os::thread_cpu_time(Thread::current(), user_sys_cpu_time);
4012 #else
4013   Unimplemented();
4014   return 0;
4015 #endif
4016 }
4017 
4018 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4019 #ifdef __APPLE__
4020   struct thread_basic_info tinfo;
4021   mach_msg_type_number_t tcount = THREAD_INFO_MAX;
4022   kern_return_t kr;
4023   thread_t mach_thread;
4024 
4025   mach_thread = thread->osthread()->thread_id();
4026   kr = thread_info(mach_thread, THREAD_BASIC_INFO, (thread_info_t)&tinfo, &tcount);
4027   if (kr != KERN_SUCCESS) {
4028     return -1;
4029   }
4030 
4031   if (user_sys_cpu_time) {
4032     jlong nanos;
4033     nanos = ((jlong) tinfo.system_time.seconds + tinfo.user_time.seconds) * (jlong)1000000000;
4034     nanos += ((jlong) tinfo.system_time.microseconds + (jlong) tinfo.user_time.microseconds) * (jlong)1000;
4035     return nanos;
4036   } else {
4037     return ((jlong)tinfo.user_time.seconds * 1000000000) + ((jlong)tinfo.user_time.microseconds * (jlong)1000);
4038   }
4039 #else
4040   Unimplemented();
4041   return 0;
4042 #endif
4043 }
4044 
4045 
4046 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4047   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
4048   info_ptr->may_skip_backward = false;     // elapsed time not wall time
4049   info_ptr->may_skip_forward = false;      // elapsed time not wall time
4050   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
4051 }
4052 
4053 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4054   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
4055   info_ptr->may_skip_backward = false;     // elapsed time not wall time
4056   info_ptr->may_skip_forward = false;      // elapsed time not wall time
4057   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
4058 }
4059 
4060 bool os::is_thread_cpu_time_supported() {
4061 #ifdef __APPLE__
4062   return true;
4063 #else
4064   return false;
4065 #endif
4066 }
4067 
4068 // System loadavg support.  Returns -1 if load average cannot be obtained.
4069 // Bsd doesn't yet have a (official) notion of processor sets,
4070 // so just return the system wide load average.
4071 int os::loadavg(double loadavg[], int nelem) {
4072   return ::getloadavg(loadavg, nelem);
4073 }
4074 
4075 void os::pause() {
4076   char filename[MAX_PATH];
4077   if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4078     jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4079   } else {
4080     jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4081   }
4082 
4083   int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4084   if (fd != -1) {
4085     struct stat buf;
4086     ::close(fd);
4087     while (::stat(filename, &buf) == 0) {
4088       (void)::poll(NULL, 0, 100);
4089     }
4090   } else {
4091     jio_fprintf(stderr,
4092                 "Could not open pause file '%s', continuing immediately.\n", filename);
4093   }
4094 }
4095 
4096 
4097 // Refer to the comments in os_solaris.cpp park-unpark. The next two
4098 // comment paragraphs are worth repeating here:
4099 //
4100 // Assumption:
4101 //    Only one parker can exist on an event, which is why we allocate
4102 //    them per-thread. Multiple unparkers can coexist.
4103 //
4104 // _Event serves as a restricted-range semaphore.
4105 //   -1 : thread is blocked, i.e. there is a waiter
4106 //    0 : neutral: thread is running or ready,
4107 //        could have been signaled after a wait started
4108 //    1 : signaled - thread is running or ready
4109 //
4110 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4111 // hang indefinitely.  For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4112 // For specifics regarding the bug see GLIBC BUGID 261237 :
4113 //    http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4114 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4115 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4116 // is used.  (The simple C test-case provided in the GLIBC bug report manifests the
4117 // hang).  The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4118 // and monitorenter when we're using 1-0 locking.  All those operations may result in
4119 // calls to pthread_cond_timedwait().  Using LD_ASSUME_KERNEL to use an older version
4120 // of libpthread avoids the problem, but isn't practical.
4121 //
4122 // Possible remedies:
4123 //
4124 // 1.   Establish a minimum relative wait time.  50 to 100 msecs seems to work.
4125 //      This is palliative and probabilistic, however.  If the thread is preempted
4126 //      between the call to compute_abstime() and pthread_cond_timedwait(), more
4127 //      than the minimum period may have passed, and the abstime may be stale (in the
4128 //      past) resultin in a hang.   Using this technique reduces the odds of a hang
4129 //      but the JVM is still vulnerable, particularly on heavily loaded systems.
4130 //
4131 // 2.   Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4132 //      of the usual flag-condvar-mutex idiom.  The write side of the pipe is set
4133 //      NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4134 //      reduces to poll()+read().  This works well, but consumes 2 FDs per extant
4135 //      thread.
4136 //
4137 // 3.   Embargo pthread_cond_timedwait() and implement a native "chron" thread
4138 //      that manages timeouts.  We'd emulate pthread_cond_timedwait() by enqueuing
4139 //      a timeout request to the chron thread and then blocking via pthread_cond_wait().
4140 //      This also works well.  In fact it avoids kernel-level scalability impediments
4141 //      on certain platforms that don't handle lots of active pthread_cond_timedwait()
4142 //      timers in a graceful fashion.
4143 //
4144 // 4.   When the abstime value is in the past it appears that control returns
4145 //      correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4146 //      Subsequent timedwait/wait calls may hang indefinitely.  Given that, we
4147 //      can avoid the problem by reinitializing the condvar -- by cond_destroy()
4148 //      followed by cond_init() -- after all calls to pthread_cond_timedwait().
4149 //      It may be possible to avoid reinitialization by checking the return
4150 //      value from pthread_cond_timedwait().  In addition to reinitializing the
4151 //      condvar we must establish the invariant that cond_signal() is only called
4152 //      within critical sections protected by the adjunct mutex.  This prevents
4153 //      cond_signal() from "seeing" a condvar that's in the midst of being
4154 //      reinitialized or that is corrupt.  Sadly, this invariant obviates the
4155 //      desirable signal-after-unlock optimization that avoids futile context switching.
4156 //
4157 //      I'm also concerned that some versions of NTPL might allocate an auxilliary
4158 //      structure when a condvar is used or initialized.  cond_destroy()  would
4159 //      release the helper structure.  Our reinitialize-after-timedwait fix
4160 //      put excessive stress on malloc/free and locks protecting the c-heap.
4161 //
4162 // We currently use (4).  See the WorkAroundNTPLTimedWaitHang flag.
4163 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4164 // and only enabling the work-around for vulnerable environments.
4165 
4166 // utility to compute the abstime argument to timedwait:
4167 // millis is the relative timeout time
4168 // abstime will be the absolute timeout time
4169 // TODO: replace compute_abstime() with unpackTime()
4170 
4171 static struct timespec* compute_abstime(struct timespec* abstime,
4172                                         jlong millis) {
4173   if (millis < 0)  millis = 0;
4174   struct timeval now;
4175   int status = gettimeofday(&now, NULL);
4176   assert(status == 0, "gettimeofday");
4177   jlong seconds = millis / 1000;
4178   millis %= 1000;
4179   if (seconds > 50000000) { // see man cond_timedwait(3T)
4180     seconds = 50000000;
4181   }
4182   abstime->tv_sec = now.tv_sec  + seconds;
4183   long       usec = now.tv_usec + millis * 1000;
4184   if (usec >= 1000000) {
4185     abstime->tv_sec += 1;
4186     usec -= 1000000;
4187   }
4188   abstime->tv_nsec = usec * 1000;
4189   return abstime;
4190 }
4191 
4192 void os::PlatformEvent::park() {       // AKA "down()"
4193   // Transitions for _Event:
4194   //   -1 => -1 : illegal
4195   //    1 =>  0 : pass - return immediately
4196   //    0 => -1 : block; then set _Event to 0 before returning
4197 
4198   // Invariant: Only the thread associated with the Event/PlatformEvent
4199   // may call park().
4200   // TODO: assert that _Assoc != NULL or _Assoc == Self
4201   assert(_nParked == 0, "invariant");
4202 
4203   int v;
4204   for (;;) {
4205     v = _Event;
4206     if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
4207   }
4208   guarantee(v >= 0, "invariant");
4209   if (v == 0) {
4210     // Do this the hard way by blocking ...
4211     int status = pthread_mutex_lock(_mutex);
4212     assert_status(status == 0, status, "mutex_lock");
4213     guarantee(_nParked == 0, "invariant");
4214     ++_nParked;
4215     while (_Event < 0) {
4216       status = pthread_cond_wait(_cond, _mutex);
4217       // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
4218       // Treat this the same as if the wait was interrupted
4219       if (status == ETIMEDOUT) { status = EINTR; }
4220       assert_status(status == 0 || status == EINTR, status, "cond_wait");
4221     }
4222     --_nParked;
4223 
4224     _Event = 0;
4225     status = pthread_mutex_unlock(_mutex);
4226     assert_status(status == 0, status, "mutex_unlock");
4227     // Paranoia to ensure our locked and lock-free paths interact
4228     // correctly with each other.
4229     OrderAccess::fence();
4230   }
4231   guarantee(_Event >= 0, "invariant");
4232 }
4233 
4234 int os::PlatformEvent::park(jlong millis) {
4235   // Transitions for _Event:
4236   //   -1 => -1 : illegal
4237   //    1 =>  0 : pass - return immediately
4238   //    0 => -1 : block; then set _Event to 0 before returning
4239 
4240   guarantee(_nParked == 0, "invariant");
4241 
4242   int v;
4243   for (;;) {
4244     v = _Event;
4245     if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
4246   }
4247   guarantee(v >= 0, "invariant");
4248   if (v != 0) return OS_OK;
4249 
4250   // We do this the hard way, by blocking the thread.
4251   // Consider enforcing a minimum timeout value.
4252   struct timespec abst;
4253   compute_abstime(&abst, millis);
4254 
4255   int ret = OS_TIMEOUT;
4256   int status = pthread_mutex_lock(_mutex);
4257   assert_status(status == 0, status, "mutex_lock");
4258   guarantee(_nParked == 0, "invariant");
4259   ++_nParked;
4260 
4261   // Object.wait(timo) will return because of
4262   // (a) notification
4263   // (b) timeout
4264   // (c) thread.interrupt
4265   //
4266   // Thread.interrupt and object.notify{All} both call Event::set.
4267   // That is, we treat thread.interrupt as a special case of notification.
4268   // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false.
4269   // We assume all ETIME returns are valid.
4270   //
4271   // TODO: properly differentiate simultaneous notify+interrupt.
4272   // In that case, we should propagate the notify to another waiter.
4273 
4274   while (_Event < 0) {
4275     status = pthread_cond_timedwait(_cond, _mutex, &abst);
4276     if (status != 0 && WorkAroundNPTLTimedWaitHang) {
4277       pthread_cond_destroy(_cond);
4278       pthread_cond_init(_cond, NULL);
4279     }
4280     assert_status(status == 0 || status == EINTR ||
4281                   status == ETIMEDOUT,
4282                   status, "cond_timedwait");
4283     if (!FilterSpuriousWakeups) break;                 // previous semantics
4284     if (status == ETIMEDOUT) break;
4285     // We consume and ignore EINTR and spurious wakeups.
4286   }
4287   --_nParked;
4288   if (_Event >= 0) {
4289     ret = OS_OK;
4290   }
4291   _Event = 0;
4292   status = pthread_mutex_unlock(_mutex);
4293   assert_status(status == 0, status, "mutex_unlock");
4294   assert(_nParked == 0, "invariant");
4295   // Paranoia to ensure our locked and lock-free paths interact
4296   // correctly with each other.
4297   OrderAccess::fence();
4298   return ret;
4299 }
4300 
4301 void os::PlatformEvent::unpark() {
4302   // Transitions for _Event:
4303   //    0 => 1 : just return
4304   //    1 => 1 : just return
4305   //   -1 => either 0 or 1; must signal target thread
4306   //         That is, we can safely transition _Event from -1 to either
4307   //         0 or 1.
4308   // See also: "Semaphores in Plan 9" by Mullender & Cox
4309   //
4310   // Note: Forcing a transition from "-1" to "1" on an unpark() means
4311   // that it will take two back-to-back park() calls for the owning
4312   // thread to block. This has the benefit of forcing a spurious return
4313   // from the first park() call after an unpark() call which will help
4314   // shake out uses of park() and unpark() without condition variables.
4315 
4316   if (Atomic::xchg(1, &_Event) >= 0) return;
4317 
4318   // Wait for the thread associated with the event to vacate
4319   int status = pthread_mutex_lock(_mutex);
4320   assert_status(status == 0, status, "mutex_lock");
4321   int AnyWaiters = _nParked;
4322   assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
4323   if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
4324     AnyWaiters = 0;
4325     pthread_cond_signal(_cond);
4326   }
4327   status = pthread_mutex_unlock(_mutex);
4328   assert_status(status == 0, status, "mutex_unlock");
4329   if (AnyWaiters != 0) {
4330     // Note that we signal() *after* dropping the lock for "immortal" Events.
4331     // This is safe and avoids a common class of  futile wakeups.  In rare
4332     // circumstances this can cause a thread to return prematurely from
4333     // cond_{timed}wait() but the spurious wakeup is benign and the victim
4334     // will simply re-test the condition and re-park itself.
4335     // This provides particular benefit if the underlying platform does not
4336     // provide wait morphing.
4337     status = pthread_cond_signal(_cond);
4338     assert_status(status == 0, status, "cond_signal");
4339   }
4340 }
4341 
4342 
4343 // JSR166
4344 // -------------------------------------------------------
4345 
4346 // The solaris and bsd implementations of park/unpark are fairly
4347 // conservative for now, but can be improved. They currently use a
4348 // mutex/condvar pair, plus a a count.
4349 // Park decrements count if > 0, else does a condvar wait.  Unpark
4350 // sets count to 1 and signals condvar.  Only one thread ever waits
4351 // on the condvar. Contention seen when trying to park implies that someone
4352 // is unparking you, so don't wait. And spurious returns are fine, so there
4353 // is no need to track notifications.
4354 
4355 #define MAX_SECS 100000000
4356 
4357 // This code is common to bsd and solaris and will be moved to a
4358 // common place in dolphin.
4359 //
4360 // The passed in time value is either a relative time in nanoseconds
4361 // or an absolute time in milliseconds. Either way it has to be unpacked
4362 // into suitable seconds and nanoseconds components and stored in the
4363 // given timespec structure.
4364 // Given time is a 64-bit value and the time_t used in the timespec is only
4365 // a signed-32-bit value (except on 64-bit Bsd) we have to watch for
4366 // overflow if times way in the future are given. Further on Solaris versions
4367 // prior to 10 there is a restriction (see cond_timedwait) that the specified
4368 // number of seconds, in abstime, is less than current_time  + 100,000,000.
4369 // As it will be 28 years before "now + 100000000" will overflow we can
4370 // ignore overflow and just impose a hard-limit on seconds using the value
4371 // of "now + 100,000,000". This places a limit on the timeout of about 3.17
4372 // years from "now".
4373 
4374 static void unpackTime(struct timespec* absTime, bool isAbsolute, jlong time) {
4375   assert(time > 0, "convertTime");
4376 
4377   struct timeval now;
4378   int status = gettimeofday(&now, NULL);
4379   assert(status == 0, "gettimeofday");
4380 
4381   time_t max_secs = now.tv_sec + MAX_SECS;
4382 
4383   if (isAbsolute) {
4384     jlong secs = time / 1000;
4385     if (secs > max_secs) {
4386       absTime->tv_sec = max_secs;
4387     } else {
4388       absTime->tv_sec = secs;
4389     }
4390     absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
4391   } else {
4392     jlong secs = time / NANOSECS_PER_SEC;
4393     if (secs >= MAX_SECS) {
4394       absTime->tv_sec = max_secs;
4395       absTime->tv_nsec = 0;
4396     } else {
4397       absTime->tv_sec = now.tv_sec + secs;
4398       absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
4399       if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
4400         absTime->tv_nsec -= NANOSECS_PER_SEC;
4401         ++absTime->tv_sec; // note: this must be <= max_secs
4402       }
4403     }
4404   }
4405   assert(absTime->tv_sec >= 0, "tv_sec < 0");
4406   assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
4407   assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
4408   assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
4409 }
4410 
4411 void Parker::park(bool isAbsolute, jlong time) {
4412   // Ideally we'd do something useful while spinning, such
4413   // as calling unpackTime().
4414 
4415   // Optional fast-path check:
4416   // Return immediately if a permit is available.
4417   // We depend on Atomic::xchg() having full barrier semantics
4418   // since we are doing a lock-free update to _counter.
4419   if (Atomic::xchg(0, &_counter) > 0) return;
4420 
4421   Thread* thread = Thread::current();
4422   assert(thread->is_Java_thread(), "Must be JavaThread");
4423   JavaThread *jt = (JavaThread *)thread;
4424 
4425   // Optional optimization -- avoid state transitions if there's an interrupt pending.
4426   // Check interrupt before trying to wait
4427   if (Thread::is_interrupted(thread, false)) {
4428     return;
4429   }
4430 
4431   // Next, demultiplex/decode time arguments
4432   struct timespec absTime;
4433   if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
4434     return;
4435   }
4436   if (time > 0) {
4437     unpackTime(&absTime, isAbsolute, time);
4438   }
4439 
4440 
4441   // Enter safepoint region
4442   // Beware of deadlocks such as 6317397.
4443   // The per-thread Parker:: mutex is a classic leaf-lock.
4444   // In particular a thread must never block on the Threads_lock while
4445   // holding the Parker:: mutex.  If safepoints are pending both the
4446   // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
4447   ThreadBlockInVM tbivm(jt);
4448 
4449   // Don't wait if cannot get lock since interference arises from
4450   // unblocking.  Also. check interrupt before trying wait
4451   if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
4452     return;
4453   }
4454 
4455   int status;
4456   if (_counter > 0)  { // no wait needed
4457     _counter = 0;
4458     status = pthread_mutex_unlock(_mutex);
4459     assert(status == 0, "invariant");
4460     // Paranoia to ensure our locked and lock-free paths interact
4461     // correctly with each other and Java-level accesses.
4462     OrderAccess::fence();
4463     return;
4464   }
4465 
4466 #ifdef ASSERT
4467   // Don't catch signals while blocked; let the running threads have the signals.
4468   // (This allows a debugger to break into the running thread.)
4469   sigset_t oldsigs;
4470   sigset_t* allowdebug_blocked = os::Bsd::allowdebug_blocked_signals();
4471   pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
4472 #endif
4473 
4474   OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
4475   jt->set_suspend_equivalent();
4476   // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
4477 
4478   if (time == 0) {
4479     status = pthread_cond_wait(_cond, _mutex);
4480   } else {
4481     status = pthread_cond_timedwait(_cond, _mutex, &absTime);
4482     if (status != 0 && WorkAroundNPTLTimedWaitHang) {
4483       pthread_cond_destroy(_cond);
4484       pthread_cond_init(_cond, NULL);
4485     }
4486   }
4487   assert_status(status == 0 || status == EINTR ||
4488                 status == ETIMEDOUT,
4489                 status, "cond_timedwait");
4490 
4491 #ifdef ASSERT
4492   pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
4493 #endif
4494 
4495   _counter = 0;
4496   status = pthread_mutex_unlock(_mutex);
4497   assert_status(status == 0, status, "invariant");
4498   // Paranoia to ensure our locked and lock-free paths interact
4499   // correctly with each other and Java-level accesses.
4500   OrderAccess::fence();
4501 
4502   // If externally suspended while waiting, re-suspend
4503   if (jt->handle_special_suspend_equivalent_condition()) {
4504     jt->java_suspend_self();
4505   }
4506 }
4507 
4508 void Parker::unpark() {
4509   int status = pthread_mutex_lock(_mutex);
4510   assert(status == 0, "invariant");
4511   const int s = _counter;
4512   _counter = 1;
4513   if (s < 1) {
4514     if (WorkAroundNPTLTimedWaitHang) {
4515       status = pthread_cond_signal(_cond);
4516       assert(status == 0, "invariant");
4517       status = pthread_mutex_unlock(_mutex);
4518       assert(status == 0, "invariant");
4519     } else {
4520       status = pthread_mutex_unlock(_mutex);
4521       assert(status == 0, "invariant");
4522       status = pthread_cond_signal(_cond);
4523       assert(status == 0, "invariant");
4524     }
4525   } else {
4526     pthread_mutex_unlock(_mutex);
4527     assert(status == 0, "invariant");
4528   }
4529 }
4530 
4531 
4532 // Darwin has no "environ" in a dynamic library.
4533 #ifdef __APPLE__
4534   #include <crt_externs.h>
4535   #define environ (*_NSGetEnviron())
4536 #else
4537 extern char** environ;
4538 #endif
4539 
4540 // Run the specified command in a separate process. Return its exit value,
4541 // or -1 on failure (e.g. can't fork a new process).
4542 // Unlike system(), this function can be called from signal handler. It
4543 // doesn't block SIGINT et al.
4544 int os::fork_and_exec(char* cmd) {
4545   const char * argv[4] = {"sh", "-c", cmd, NULL};
4546 
4547   // fork() in BsdThreads/NPTL is not async-safe. It needs to run
4548   // pthread_atfork handlers and reset pthread library. All we need is a
4549   // separate process to execve. Make a direct syscall to fork process.
4550   // On IA64 there's no fork syscall, we have to use fork() and hope for
4551   // the best...
4552   pid_t pid = fork();
4553 
4554   if (pid < 0) {
4555     // fork failed
4556     return -1;
4557 
4558   } else if (pid == 0) {
4559     // child process
4560 
4561     // execve() in BsdThreads will call pthread_kill_other_threads_np()
4562     // first to kill every thread on the thread list. Because this list is
4563     // not reset by fork() (see notes above), execve() will instead kill
4564     // every thread in the parent process. We know this is the only thread
4565     // in the new process, so make a system call directly.
4566     // IA64 should use normal execve() from glibc to match the glibc fork()
4567     // above.
4568     execve("/bin/sh", (char* const*)argv, environ);
4569 
4570     // execve failed
4571     _exit(-1);
4572 
4573   } else  {
4574     // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
4575     // care about the actual exit code, for now.
4576 
4577     int status;
4578 
4579     // Wait for the child process to exit.  This returns immediately if
4580     // the child has already exited. */
4581     while (waitpid(pid, &status, 0) < 0) {
4582       switch (errno) {
4583       case ECHILD: return 0;
4584       case EINTR: break;
4585       default: return -1;
4586       }
4587     }
4588 
4589     if (WIFEXITED(status)) {
4590       // The child exited normally; get its exit code.
4591       return WEXITSTATUS(status);
4592     } else if (WIFSIGNALED(status)) {
4593       // The child exited because of a signal
4594       // The best value to return is 0x80 + signal number,
4595       // because that is what all Unix shells do, and because
4596       // it allows callers to distinguish between process exit and
4597       // process death by signal.
4598       return 0x80 + WTERMSIG(status);
4599     } else {
4600       // Unknown exit code; pass it through
4601       return status;
4602     }
4603   }
4604 }
4605 
4606 // is_headless_jre()
4607 //
4608 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
4609 // in order to report if we are running in a headless jre
4610 //
4611 // Since JDK8 xawt/libmawt.so was moved into the same directory
4612 // as libawt.so, and renamed libawt_xawt.so
4613 //
4614 bool os::is_headless_jre() {
4615 #ifdef __APPLE__
4616   // We no longer build headless-only on Mac OS X
4617   return false;
4618 #else
4619   struct stat statbuf;
4620   char buf[MAXPATHLEN];
4621   char libmawtpath[MAXPATHLEN];
4622   const char *xawtstr  = "/xawt/libmawt" JNI_LIB_SUFFIX;
4623   const char *new_xawtstr = "/libawt_xawt" JNI_LIB_SUFFIX;
4624   char *p;
4625 
4626   // Get path to libjvm.so
4627   os::jvm_path(buf, sizeof(buf));
4628 
4629   // Get rid of libjvm.so
4630   p = strrchr(buf, '/');
4631   if (p == NULL) {
4632     return false;
4633   } else {
4634     *p = '\0';
4635   }
4636 
4637   // Get rid of client or server
4638   p = strrchr(buf, '/');
4639   if (p == NULL) {
4640     return false;
4641   } else {
4642     *p = '\0';
4643   }
4644 
4645   // check xawt/libmawt.so
4646   strcpy(libmawtpath, buf);
4647   strcat(libmawtpath, xawtstr);
4648   if (::stat(libmawtpath, &statbuf) == 0) return false;
4649 
4650   // check libawt_xawt.so
4651   strcpy(libmawtpath, buf);
4652   strcat(libmawtpath, new_xawtstr);
4653   if (::stat(libmawtpath, &statbuf) == 0) return false;
4654 
4655   return true;
4656 #endif
4657 }
4658 
4659 // Get the default path to the core file
4660 // Returns the length of the string
4661 int os::get_core_path(char* buffer, size_t bufferSize) {
4662   int n = jio_snprintf(buffer, bufferSize, "/cores/core.%d", current_process_id());
4663 
4664   // Truncate if theoretical string was longer than bufferSize
4665   n = MIN2(n, (int)bufferSize);
4666 
4667   return n;
4668 }
4669 
4670 #ifndef PRODUCT
4671 void TestReserveMemorySpecial_test() {
4672   // No tests available for this platform
4673 }
4674 #endif