1 /*
   2  * Copyright (c) 1999, 2014, 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 "services/attachListener.hpp"
  63 #include "services/memTracker.hpp"
  64 #include "services/runtimeService.hpp"
  65 #include "utilities/decoder.hpp"
  66 #include "utilities/defaultStream.hpp"
  67 #include "utilities/events.hpp"
  68 #include "utilities/growableArray.hpp"
  69 #include "utilities/vmError.hpp"
  70 
  71 // put OS-includes here
  72 # include <sys/types.h>
  73 # include <sys/mman.h>
  74 # include <sys/stat.h>
  75 # include <sys/select.h>
  76 # include <pthread.h>
  77 # include <signal.h>
  78 # include <errno.h>
  79 # include <dlfcn.h>
  80 # include <stdio.h>
  81 # include <unistd.h>
  82 # include <sys/resource.h>
  83 # include <pthread.h>
  84 # include <sys/stat.h>
  85 # include <sys/time.h>
  86 # include <sys/times.h>
  87 # include <sys/utsname.h>
  88 # include <sys/socket.h>
  89 # include <sys/wait.h>
  90 # include <time.h>
  91 # include <pwd.h>
  92 # include <poll.h>
  93 # include <semaphore.h>
  94 # include <fcntl.h>
  95 # include <string.h>
  96 # include <sys/param.h>
  97 # include <sys/sysctl.h>
  98 # include <sys/ipc.h>
  99 # include <sys/shm.h>
 100 #ifndef __APPLE__
 101 # include <link.h>
 102 #endif
 103 # include <stdint.h>
 104 # include <inttypes.h>
 105 # include <sys/ioctl.h>
 106 # include <sys/syscall.h>
 107 
 108 #if defined(__FreeBSD__) || defined(__NetBSD__)
 109 # include <elf.h>
 110 #endif
 111 
 112 #ifdef __APPLE__
 113 # include <mach/mach.h> // semaphore_* API
 114 # include <mach-o/dyld.h>
 115 # include <sys/proc_info.h>
 116 # include <objc/objc-auto.h>
 117 #endif
 118 
 119 #ifndef MAP_ANONYMOUS
 120 #define MAP_ANONYMOUS MAP_ANON
 121 #endif
 122 
 123 #define MAX_PATH    (2 * K)
 124 
 125 // for timer info max values which include all bits
 126 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
 127 
 128 #define LARGEPAGES_BIT (1 << 6)
 129 
 130 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
 131 
 132 ////////////////////////////////////////////////////////////////////////////////
 133 // global variables
 134 julong os::Bsd::_physical_memory = 0;
 135 
 136 #ifdef __APPLE__
 137 mach_timebase_info_data_t os::Bsd::_timebase_info = {0, 0};
 138 volatile uint64_t         os::Bsd::_max_abstime   = 0;
 139 #else
 140 int (*os::Bsd::_clock_gettime)(clockid_t, struct timespec *) = NULL;
 141 #endif
 142 pthread_t os::Bsd::_main_thread;
 143 int os::Bsd::_page_size = -1;
 144 
 145 static jlong initial_time_count=0;
 146 
 147 static int clock_tics_per_sec = 100;
 148 
 149 // For diagnostics to print a message once. see run_periodic_checks
 150 static sigset_t check_signal_done;
 151 static bool check_signals = true;
 152 
 153 static pid_t _initial_pid = 0;
 154 
 155 /* Signal number used to suspend/resume a thread */
 156 
 157 /* do not use any signal number less than SIGSEGV, see 4355769 */
 158 static int SR_signum = SIGUSR2;
 159 sigset_t SR_sigset;
 160 
 161 
 162 ////////////////////////////////////////////////////////////////////////////////
 163 // utility functions
 164 
 165 static int SR_initialize();
 166 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
 167 
 168 julong os::available_memory() {
 169   return Bsd::available_memory();
 170 }
 171 
 172 // available here means free
 173 julong os::Bsd::available_memory() {
 174   uint64_t available = physical_memory() >> 2;
 175 #ifdef __APPLE__
 176   mach_msg_type_number_t count = HOST_VM_INFO64_COUNT;
 177   vm_statistics64_data_t vmstat;
 178   kern_return_t kerr = host_statistics64(mach_host_self(), HOST_VM_INFO64,
 179                                          (host_info64_t)&vmstat, &count);
 180   assert(kerr == KERN_SUCCESS,
 181          "host_statistics64 failed - check mach_host_self() and count");
 182   if (kerr == KERN_SUCCESS) {
 183     available = vmstat.free_count * os::vm_page_size();
 184   }
 185 #endif
 186   return available;
 187 }
 188 
 189 julong os::physical_memory() {
 190   return Bsd::physical_memory();
 191 }
 192 
 193 ////////////////////////////////////////////////////////////////////////////////
 194 // environment support
 195 
 196 bool os::getenv(const char* name, char* buf, int len) {
 197   const char* val = ::getenv(name);
 198   if (val != NULL && strlen(val) < (size_t)len) {
 199     strcpy(buf, val);
 200     return true;
 201   }
 202   if (len > 0) buf[0] = 0;  // return a null string
 203   return false;
 204 }
 205 
 206 
 207 // Return true if user is running as root.
 208 
 209 bool os::have_special_privileges() {
 210   static bool init = false;
 211   static bool privileges = false;
 212   if (!init) {
 213     privileges = (getuid() != geteuid()) || (getgid() != getegid());
 214     init = true;
 215   }
 216   return privileges;
 217 }
 218 
 219 
 220 
 221 // Cpu architecture string
 222 #if   defined(ZERO)
 223 static char cpu_arch[] = ZERO_LIBARCH;
 224 #elif defined(IA64)
 225 static char cpu_arch[] = "ia64";
 226 #elif defined(IA32)
 227 static char cpu_arch[] = "i386";
 228 #elif defined(AMD64)
 229 static char cpu_arch[] = "amd64";
 230 #elif defined(ARM)
 231 static char cpu_arch[] = "arm";
 232 #elif defined(PPC32)
 233 static char cpu_arch[] = "ppc";
 234 #elif defined(SPARC)
 235 #  ifdef _LP64
 236 static char cpu_arch[] = "sparcv9";
 237 #  else
 238 static char cpu_arch[] = "sparc";
 239 #  endif
 240 #else
 241 #error Add appropriate cpu_arch setting
 242 #endif
 243 
 244 // Compiler variant
 245 #ifdef COMPILER2
 246 #define COMPILER_VARIANT "server"
 247 #else
 248 #define COMPILER_VARIANT "client"
 249 #endif
 250 
 251 
 252 void os::Bsd::initialize_system_info() {
 253   int mib[2];
 254   size_t len;
 255   int cpu_val;
 256   julong mem_val;
 257 
 258   /* get processors count via hw.ncpus sysctl */
 259   mib[0] = CTL_HW;
 260   mib[1] = HW_NCPU;
 261   len = sizeof(cpu_val);
 262   if (sysctl(mib, 2, &cpu_val, &len, NULL, 0) != -1 && cpu_val >= 1) {
 263        assert(len == sizeof(cpu_val), "unexpected data size");
 264        set_processor_count(cpu_val);
 265   }
 266   else {
 267        set_processor_count(1);   // fallback
 268   }
 269 
 270   /* get physical memory via hw.memsize sysctl (hw.memsize is used
 271    * since it returns a 64 bit value)
 272    */
 273   mib[0] = CTL_HW;
 274 
 275 #if defined (HW_MEMSIZE) // Apple
 276   mib[1] = HW_MEMSIZE;
 277 #elif defined(HW_PHYSMEM) // Most of BSD
 278   mib[1] = HW_PHYSMEM;
 279 #elif defined(HW_REALMEM) // Old FreeBSD
 280   mib[1] = HW_REALMEM;
 281 #else
 282   #error No ways to get physmem
 283 #endif
 284 
 285   len = sizeof(mem_val);
 286   if (sysctl(mib, 2, &mem_val, &len, NULL, 0) != -1) {
 287        assert(len == sizeof(mem_val), "unexpected data size");
 288        _physical_memory = mem_val;
 289   } else {
 290        _physical_memory = 256*1024*1024;       // fallback (XXXBSD?)
 291   }
 292 
 293 #ifdef __OpenBSD__
 294   {
 295        // limit _physical_memory memory view on OpenBSD since
 296        // datasize rlimit restricts us anyway.
 297        struct rlimit limits;
 298        getrlimit(RLIMIT_DATA, &limits);
 299        _physical_memory = MIN2(_physical_memory, (julong)limits.rlim_cur);
 300   }
 301 #endif
 302 }
 303 
 304 #ifdef __APPLE__
 305 static const char *get_home() {
 306   const char *home_dir = ::getenv("HOME");
 307   if ((home_dir == NULL) || (*home_dir == '\0')) {
 308     struct passwd *passwd_info = getpwuid(geteuid());
 309     if (passwd_info != NULL) {
 310       home_dir = passwd_info->pw_dir;
 311     }
 312   }
 313 
 314   return home_dir;
 315 }
 316 #endif
 317 
 318 void os::init_system_properties_values() {
 319   // The next steps are taken in the product version:
 320   //
 321   // Obtain the JAVA_HOME value from the location of libjvm.so.
 322   // This library should be located at:
 323   // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so.
 324   //
 325   // If "/jre/lib/" appears at the right place in the path, then we
 326   // assume libjvm.so is installed in a JDK and we use this path.
 327   //
 328   // Otherwise exit with message: "Could not create the Java virtual machine."
 329   //
 330   // The following extra steps are taken in the debugging version:
 331   //
 332   // If "/jre/lib/" does NOT appear at the right place in the path
 333   // instead of exit check for $JAVA_HOME environment variable.
 334   //
 335   // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
 336   // then we append a fake suffix "hotspot/libjvm.so" to this path so
 337   // it looks like libjvm.so is installed there
 338   // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
 339   //
 340   // Otherwise exit.
 341   //
 342   // Important note: if the location of libjvm.so changes this
 343   // code needs to be changed accordingly.
 344 
 345 // See ld(1):
 346 //      The linker uses the following search paths to locate required
 347 //      shared libraries:
 348 //        1: ...
 349 //        ...
 350 //        7: The default directories, normally /lib and /usr/lib.
 351 #ifndef DEFAULT_LIBPATH
 352 #define DEFAULT_LIBPATH "/lib:/usr/lib"
 353 #endif
 354 
 355 // Base path of extensions installed on the system.
 356 #define SYS_EXT_DIR     "/usr/java/packages"
 357 #define EXTENSIONS_DIR  "/lib/ext"
 358 #define ENDORSED_DIR    "/lib/endorsed"
 359 
 360 #ifndef __APPLE__
 361 
 362   // Buffer that fits several sprintfs.
 363   // Note that the space for the colon and the trailing null are provided
 364   // by the nulls included by the sizeof operator.
 365   const size_t bufsize =
 366     MAX3((size_t)MAXPATHLEN,  // For dll_dir & friends.
 367          (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR), // extensions dir
 368          (size_t)MAXPATHLEN + sizeof(ENDORSED_DIR)); // endorsed dir
 369   char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
 370 
 371   // sysclasspath, java_home, dll_dir
 372   {
 373     char *pslash;
 374     os::jvm_path(buf, bufsize);
 375 
 376     // Found the full path to libjvm.so.
 377     // Now cut the path to <java_home>/jre if we can.
 378     *(strrchr(buf, '/')) = '\0'; // Get rid of /libjvm.so.
 379     pslash = strrchr(buf, '/');
 380     if (pslash != NULL) {
 381       *pslash = '\0';            // Get rid of /{client|server|hotspot}.
 382     }
 383     Arguments::set_dll_dir(buf);
 384 
 385     if (pslash != NULL) {
 386       pslash = strrchr(buf, '/');
 387       if (pslash != NULL) {
 388         *pslash = '\0';          // Get rid of /<arch>.
 389         pslash = strrchr(buf, '/');
 390         if (pslash != NULL) {
 391           *pslash = '\0';        // Get rid of /lib.
 392         }
 393       }
 394     }
 395     Arguments::set_java_home(buf);
 396     set_boot_path('/', ':');
 397   }
 398 
 399   // Where to look for native libraries.
 400   //
 401   // Note: Due to a legacy implementation, most of the library path
 402   // is set in the launcher. This was to accomodate linking restrictions
 403   // on legacy Bsd implementations (which are no longer supported).
 404   // Eventually, all the library path setting will be done here.
 405   //
 406   // However, to prevent the proliferation of improperly built native
 407   // libraries, the new path component /usr/java/packages is added here.
 408   // Eventually, all the library path setting will be done here.
 409   {
 410     // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
 411     // should always exist (until the legacy problem cited above is
 412     // addressed).
 413     const char *v = ::getenv("LD_LIBRARY_PATH");
 414     const char *v_colon = ":";
 415     if (v == NULL) { v = ""; v_colon = ""; }
 416     // That's +1 for the colon and +1 for the trailing '\0'.
 417     char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
 418                                                      strlen(v) + 1 +
 419                                                      sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1,
 420                                                      mtInternal);
 421     sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch);
 422     Arguments::set_library_path(ld_library_path);
 423     FREE_C_HEAP_ARRAY(char, ld_library_path, mtInternal);
 424   }
 425 
 426   // Extensions directories.
 427   sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
 428   Arguments::set_ext_dirs(buf);
 429 
 430   // Endorsed standards default directory.
 431   sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
 432   Arguments::set_endorsed_dirs(buf);
 433 
 434   FREE_C_HEAP_ARRAY(char, buf, mtInternal);
 435 
 436 #else // __APPLE__
 437 
 438 #define SYS_EXTENSIONS_DIR   "/Library/Java/Extensions"
 439 #define SYS_EXTENSIONS_DIRS  SYS_EXTENSIONS_DIR ":/Network" SYS_EXTENSIONS_DIR ":/System" SYS_EXTENSIONS_DIR ":/usr/lib/java"
 440 
 441   const char *user_home_dir = get_home();
 442   // The null in SYS_EXTENSIONS_DIRS counts for the size of the colon after user_home_dir.
 443   size_t system_ext_size = strlen(user_home_dir) + sizeof(SYS_EXTENSIONS_DIR) +
 444     sizeof(SYS_EXTENSIONS_DIRS);
 445 
 446   // Buffer that fits several sprintfs.
 447   // Note that the space for the colon and the trailing null are provided
 448   // by the nulls included by the sizeof operator.
 449   const size_t bufsize =
 450     MAX3((size_t)MAXPATHLEN,  // for dll_dir & friends.
 451          (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + system_ext_size, // extensions dir
 452          (size_t)MAXPATHLEN + sizeof(ENDORSED_DIR)); // endorsed dir
 453   char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
 454 
 455   // sysclasspath, java_home, dll_dir
 456   {
 457     char *pslash;
 458     os::jvm_path(buf, bufsize);
 459 
 460     // Found the full path to libjvm.so.
 461     // Now cut the path to <java_home>/jre if we can.
 462     *(strrchr(buf, '/')) = '\0'; // Get rid of /libjvm.so.
 463     pslash = strrchr(buf, '/');
 464     if (pslash != NULL) {
 465       *pslash = '\0';            // Get rid of /{client|server|hotspot}.
 466     }
 467     Arguments::set_dll_dir(buf);
 468 
 469     if (pslash != NULL) {
 470       pslash = strrchr(buf, '/');
 471       if (pslash != NULL) {
 472         *pslash = '\0';          // Get rid of /lib.
 473       }
 474     }
 475     Arguments::set_java_home(buf);
 476     set_boot_path('/', ':');
 477   }
 478 
 479   // Where to look for native libraries.
 480   //
 481   // Note: Due to a legacy implementation, most of the library path
 482   // is set in the launcher. This was to accomodate linking restrictions
 483   // on legacy Bsd implementations (which are no longer supported).
 484   // Eventually, all the library path setting will be done here.
 485   //
 486   // However, to prevent the proliferation of improperly built native
 487   // libraries, the new path component /usr/java/packages is added here.
 488   // Eventually, all the library path setting will be done here.
 489   {
 490     // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
 491     // should always exist (until the legacy problem cited above is
 492     // addressed).
 493     // Prepend the default path with the JAVA_LIBRARY_PATH so that the app launcher code
 494     // can specify a directory inside an app wrapper
 495     const char *l = ::getenv("JAVA_LIBRARY_PATH");
 496     const char *l_colon = ":";
 497     if (l == NULL) { l = ""; l_colon = ""; }
 498 
 499     const char *v = ::getenv("DYLD_LIBRARY_PATH");
 500     const char *v_colon = ":";
 501     if (v == NULL) { v = ""; v_colon = ""; }
 502 
 503     // Apple's Java6 has "." at the beginning of java.library.path.
 504     // OpenJDK on Windows has "." at the end of java.library.path.
 505     // OpenJDK on Linux and Solaris don't have "." in java.library.path
 506     // at all. To ease the transition from Apple's Java6 to OpenJDK7,
 507     // "." is appended to the end of java.library.path. Yes, this
 508     // could cause a change in behavior, but Apple's Java6 behavior
 509     // can be achieved by putting "." at the beginning of the
 510     // JAVA_LIBRARY_PATH environment variable.
 511     char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
 512                                                      strlen(v) + 1 + strlen(l) + 1 +
 513                                                      system_ext_size + 3,
 514                                                      mtInternal);
 515     sprintf(ld_library_path, "%s%s%s%s%s" SYS_EXTENSIONS_DIR ":" SYS_EXTENSIONS_DIRS ":.",
 516             v, v_colon, l, l_colon, user_home_dir);
 517     Arguments::set_library_path(ld_library_path);
 518     FREE_C_HEAP_ARRAY(char, ld_library_path, mtInternal);
 519   }
 520 
 521   // Extensions directories.
 522   //
 523   // Note that the space for the colon and the trailing null are provided
 524   // by the nulls included by the sizeof operator (so actually one byte more
 525   // than necessary is allocated).
 526   sprintf(buf, "%s" SYS_EXTENSIONS_DIR ":%s" EXTENSIONS_DIR ":" SYS_EXTENSIONS_DIRS,
 527           user_home_dir, Arguments::get_java_home());
 528   Arguments::set_ext_dirs(buf);
 529 
 530   // Endorsed standards default directory.
 531   sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
 532   Arguments::set_endorsed_dirs(buf);
 533 
 534   FREE_C_HEAP_ARRAY(char, buf, mtInternal);
 535 
 536 #undef SYS_EXTENSIONS_DIR
 537 #undef SYS_EXTENSIONS_DIRS
 538 
 539 #endif // __APPLE__
 540 
 541 #undef SYS_EXT_DIR
 542 #undef EXTENSIONS_DIR
 543 #undef ENDORSED_DIR
 544 }
 545 
 546 ////////////////////////////////////////////////////////////////////////////////
 547 // breakpoint support
 548 
 549 void os::breakpoint() {
 550   BREAKPOINT;
 551 }
 552 
 553 extern "C" void breakpoint() {
 554   // use debugger to set breakpoint here
 555 }
 556 
 557 ////////////////////////////////////////////////////////////////////////////////
 558 // signal support
 559 
 560 debug_only(static bool signal_sets_initialized = false);
 561 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
 562 
 563 bool os::Bsd::is_sig_ignored(int sig) {
 564       struct sigaction oact;
 565       sigaction(sig, (struct sigaction*)NULL, &oact);
 566       void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*,  oact.sa_sigaction)
 567                                      : CAST_FROM_FN_PTR(void*,  oact.sa_handler);
 568       if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
 569            return true;
 570       else
 571            return false;
 572 }
 573 
 574 void os::Bsd::signal_sets_init() {
 575   // Should also have an assertion stating we are still single-threaded.
 576   assert(!signal_sets_initialized, "Already initialized");
 577   // Fill in signals that are necessarily unblocked for all threads in
 578   // the VM. Currently, we unblock the following signals:
 579   // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
 580   //                         by -Xrs (=ReduceSignalUsage));
 581   // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
 582   // other threads. The "ReduceSignalUsage" boolean tells us not to alter
 583   // the dispositions or masks wrt these signals.
 584   // Programs embedding the VM that want to use the above signals for their
 585   // own purposes must, at this time, use the "-Xrs" option to prevent
 586   // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
 587   // (See bug 4345157, and other related bugs).
 588   // In reality, though, unblocking these signals is really a nop, since
 589   // these signals are not blocked by default.
 590   sigemptyset(&unblocked_sigs);
 591   sigemptyset(&allowdebug_blocked_sigs);
 592   sigaddset(&unblocked_sigs, SIGILL);
 593   sigaddset(&unblocked_sigs, SIGSEGV);
 594   sigaddset(&unblocked_sigs, SIGBUS);
 595   sigaddset(&unblocked_sigs, SIGFPE);
 596   sigaddset(&unblocked_sigs, SR_signum);
 597 
 598   if (!ReduceSignalUsage) {
 599    if (!os::Bsd::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
 600       sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
 601       sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
 602    }
 603    if (!os::Bsd::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
 604       sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
 605       sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
 606    }
 607    if (!os::Bsd::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
 608       sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
 609       sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
 610    }
 611   }
 612   // Fill in signals that are blocked by all but the VM thread.
 613   sigemptyset(&vm_sigs);
 614   if (!ReduceSignalUsage)
 615     sigaddset(&vm_sigs, BREAK_SIGNAL);
 616   debug_only(signal_sets_initialized = true);
 617 
 618 }
 619 
 620 // These are signals that are unblocked while a thread is running Java.
 621 // (For some reason, they get blocked by default.)
 622 sigset_t* os::Bsd::unblocked_signals() {
 623   assert(signal_sets_initialized, "Not initialized");
 624   return &unblocked_sigs;
 625 }
 626 
 627 // These are the signals that are blocked while a (non-VM) thread is
 628 // running Java. Only the VM thread handles these signals.
 629 sigset_t* os::Bsd::vm_signals() {
 630   assert(signal_sets_initialized, "Not initialized");
 631   return &vm_sigs;
 632 }
 633 
 634 // These are signals that are blocked during cond_wait to allow debugger in
 635 sigset_t* os::Bsd::allowdebug_blocked_signals() {
 636   assert(signal_sets_initialized, "Not initialized");
 637   return &allowdebug_blocked_sigs;
 638 }
 639 
 640 void os::Bsd::hotspot_sigmask(Thread* thread) {
 641 
 642   //Save caller's signal mask before setting VM signal mask
 643   sigset_t caller_sigmask;
 644   pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
 645 
 646   OSThread* osthread = thread->osthread();
 647   osthread->set_caller_sigmask(caller_sigmask);
 648 
 649   pthread_sigmask(SIG_UNBLOCK, os::Bsd::unblocked_signals(), NULL);
 650 
 651   if (!ReduceSignalUsage) {
 652     if (thread->is_VM_thread()) {
 653       // Only the VM thread handles BREAK_SIGNAL ...
 654       pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
 655     } else {
 656       // ... all other threads block BREAK_SIGNAL
 657       pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
 658     }
 659   }
 660 }
 661 
 662 
 663 //////////////////////////////////////////////////////////////////////////////
 664 // create new thread
 665 
 666 // check if it's safe to start a new thread
 667 static bool _thread_safety_check(Thread* thread) {
 668   return true;
 669 }
 670 
 671 #ifdef __APPLE__
 672 // library handle for calling objc_registerThreadWithCollector()
 673 // without static linking to the libobjc library
 674 #define OBJC_LIB "/usr/lib/libobjc.dylib"
 675 #define OBJC_GCREGISTER "objc_registerThreadWithCollector"
 676 typedef void (*objc_registerThreadWithCollector_t)();
 677 extern "C" objc_registerThreadWithCollector_t objc_registerThreadWithCollectorFunction;
 678 objc_registerThreadWithCollector_t objc_registerThreadWithCollectorFunction = NULL;
 679 #endif
 680 
 681 #ifdef __APPLE__
 682 static uint64_t locate_unique_thread_id(mach_port_t mach_thread_port) {
 683   // Additional thread_id used to correlate threads in SA
 684   thread_identifier_info_data_t     m_ident_info;
 685   mach_msg_type_number_t            count = THREAD_IDENTIFIER_INFO_COUNT;
 686 
 687   thread_info(mach_thread_port, THREAD_IDENTIFIER_INFO,
 688               (thread_info_t) &m_ident_info, &count);
 689 
 690   return m_ident_info.thread_id;
 691 }
 692 #endif
 693 
 694 // Thread start routine for all newly created threads
 695 static void *java_start(Thread *thread) {
 696   // Try to randomize the cache line index of hot stack frames.
 697   // This helps when threads of the same stack traces evict each other's
 698   // cache lines. The threads can be either from the same JVM instance, or
 699   // from different JVM instances. The benefit is especially true for
 700   // processors with hyperthreading technology.
 701   static int counter = 0;
 702   int pid = os::current_process_id();
 703   alloca(((pid ^ counter++) & 7) * 128);
 704 
 705   ThreadLocalStorage::set_thread(thread);
 706 
 707   OSThread* osthread = thread->osthread();
 708   Monitor* sync = osthread->startThread_lock();
 709 
 710   // non floating stack BsdThreads needs extra check, see above
 711   if (!_thread_safety_check(thread)) {
 712     // notify parent thread
 713     MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
 714     osthread->set_state(ZOMBIE);
 715     sync->notify_all();
 716     return NULL;
 717   }
 718 
 719   osthread->set_thread_id(os::Bsd::gettid());
 720 
 721 #ifdef __APPLE__
 722   uint64_t unique_thread_id = locate_unique_thread_id(osthread->thread_id());
 723   guarantee(unique_thread_id != 0, "unique thread id was not found");
 724   osthread->set_unique_thread_id(unique_thread_id);
 725 #endif
 726   // initialize signal mask for this thread
 727   os::Bsd::hotspot_sigmask(thread);
 728 
 729   // initialize floating point control register
 730   os::Bsd::init_thread_fpu_state();
 731 
 732 #ifdef __APPLE__
 733   // register thread with objc gc
 734   if (objc_registerThreadWithCollectorFunction != NULL) {
 735     objc_registerThreadWithCollectorFunction();
 736   }
 737 #endif
 738 
 739   // handshaking with parent thread
 740   {
 741     MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
 742 
 743     // notify parent thread
 744     osthread->set_state(INITIALIZED);
 745     sync->notify_all();
 746 
 747     // wait until os::start_thread()
 748     while (osthread->get_state() == INITIALIZED) {
 749       sync->wait(Mutex::_no_safepoint_check_flag);
 750     }
 751   }
 752 
 753   // call one more level start routine
 754   thread->run();
 755 
 756   return 0;
 757 }
 758 
 759 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
 760   assert(thread->osthread() == NULL, "caller responsible");
 761 
 762   // Allocate the OSThread object
 763   OSThread* osthread = new OSThread(NULL, NULL);
 764   if (osthread == NULL) {
 765     return false;
 766   }
 767 
 768   // set the correct thread state
 769   osthread->set_thread_type(thr_type);
 770 
 771   // Initial state is ALLOCATED but not INITIALIZED
 772   osthread->set_state(ALLOCATED);
 773 
 774   thread->set_osthread(osthread);
 775 
 776   // init thread attributes
 777   pthread_attr_t attr;
 778   pthread_attr_init(&attr);
 779   pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 780 
 781   // stack size
 782   if (os::Bsd::supports_variable_stack_size()) {
 783     // calculate stack size if it's not specified by caller
 784     if (stack_size == 0) {
 785       stack_size = os::Bsd::default_stack_size(thr_type);
 786 
 787       switch (thr_type) {
 788       case os::java_thread:
 789         // Java threads use ThreadStackSize which default value can be
 790         // changed with the flag -Xss
 791         assert(JavaThread::stack_size_at_create() > 0, "this should be set");
 792         stack_size = JavaThread::stack_size_at_create();
 793         break;
 794       case os::compiler_thread:
 795         if (CompilerThreadStackSize > 0) {
 796           stack_size = (size_t)(CompilerThreadStackSize * K);
 797           break;
 798         } // else fall through:
 799           // use VMThreadStackSize if CompilerThreadStackSize is not defined
 800       case os::vm_thread:
 801       case os::pgc_thread:
 802       case os::cgc_thread:
 803       case os::watcher_thread:
 804         if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
 805         break;
 806       }
 807     }
 808 
 809     stack_size = MAX2(stack_size, os::Bsd::min_stack_allowed);
 810     pthread_attr_setstacksize(&attr, stack_size);
 811   } else {
 812     // let pthread_create() pick the default value.
 813   }
 814 
 815   ThreadState state;
 816 
 817   {
 818     pthread_t tid;
 819     int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
 820 
 821     pthread_attr_destroy(&attr);
 822 
 823     if (ret != 0) {
 824       if (PrintMiscellaneous && (Verbose || WizardMode)) {
 825         perror("pthread_create()");
 826       }
 827       // Need to clean up stuff we've allocated so far
 828       thread->set_osthread(NULL);
 829       delete osthread;
 830       return false;
 831     }
 832 
 833     // Store pthread info into the OSThread
 834     osthread->set_pthread_id(tid);
 835 
 836     // Wait until child thread is either initialized or aborted
 837     {
 838       Monitor* sync_with_child = osthread->startThread_lock();
 839       MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
 840       while ((state = osthread->get_state()) == ALLOCATED) {
 841         sync_with_child->wait(Mutex::_no_safepoint_check_flag);
 842       }
 843     }
 844 
 845   }
 846 
 847   // Aborted due to thread limit being reached
 848   if (state == ZOMBIE) {
 849       thread->set_osthread(NULL);
 850       delete osthread;
 851       return false;
 852   }
 853 
 854   // The thread is returned suspended (in state INITIALIZED),
 855   // and is started higher up in the call chain
 856   assert(state == INITIALIZED, "race condition");
 857   return true;
 858 }
 859 
 860 /////////////////////////////////////////////////////////////////////////////
 861 // attach existing thread
 862 
 863 // bootstrap the main thread
 864 bool os::create_main_thread(JavaThread* thread) {
 865   assert(os::Bsd::_main_thread == pthread_self(), "should be called inside main thread");
 866   return create_attached_thread(thread);
 867 }
 868 
 869 bool os::create_attached_thread(JavaThread* thread) {
 870 #ifdef ASSERT
 871     thread->verify_not_published();
 872 #endif
 873 
 874   // Allocate the OSThread object
 875   OSThread* osthread = new OSThread(NULL, NULL);
 876 
 877   if (osthread == NULL) {
 878     return false;
 879   }
 880 
 881   osthread->set_thread_id(os::Bsd::gettid());
 882 
 883   // Store pthread info into the OSThread
 884 #ifdef __APPLE__
 885   uint64_t unique_thread_id = locate_unique_thread_id(osthread->thread_id());
 886   guarantee(unique_thread_id != 0, "just checking");
 887   osthread->set_unique_thread_id(unique_thread_id);
 888 #endif
 889   osthread->set_pthread_id(::pthread_self());
 890 
 891   // initialize floating point control register
 892   os::Bsd::init_thread_fpu_state();
 893 
 894   // Initial thread state is RUNNABLE
 895   osthread->set_state(RUNNABLE);
 896 
 897   thread->set_osthread(osthread);
 898 
 899   // initialize signal mask for this thread
 900   // and save the caller's signal mask
 901   os::Bsd::hotspot_sigmask(thread);
 902 
 903   return true;
 904 }
 905 
 906 void os::pd_start_thread(Thread* thread) {
 907   OSThread * osthread = thread->osthread();
 908   assert(osthread->get_state() != INITIALIZED, "just checking");
 909   Monitor* sync_with_child = osthread->startThread_lock();
 910   MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
 911   sync_with_child->notify();
 912 }
 913 
 914 // Free Bsd resources related to the OSThread
 915 void os::free_thread(OSThread* osthread) {
 916   assert(osthread != NULL, "osthread not set");
 917 
 918   if (Thread::current()->osthread() == osthread) {
 919     // Restore caller's signal mask
 920     sigset_t sigmask = osthread->caller_sigmask();
 921     pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
 922    }
 923 
 924   delete osthread;
 925 }
 926 
 927 //////////////////////////////////////////////////////////////////////////////
 928 // thread local storage
 929 
 930 // Restore the thread pointer if the destructor is called. This is in case
 931 // someone from JNI code sets up a destructor with pthread_key_create to run
 932 // detachCurrentThread on thread death. Unless we restore the thread pointer we
 933 // will hang or crash. When detachCurrentThread is called the key will be set
 934 // to null and we will not be called again. If detachCurrentThread is never
 935 // called we could loop forever depending on the pthread implementation.
 936 static void restore_thread_pointer(void* p) {
 937   Thread* thread = (Thread*) p;
 938   os::thread_local_storage_at_put(ThreadLocalStorage::thread_index(), thread);
 939 }
 940 
 941 int os::allocate_thread_local_storage() {
 942   pthread_key_t key;
 943   int rslt = pthread_key_create(&key, restore_thread_pointer);
 944   assert(rslt == 0, "cannot allocate thread local storage");
 945   return (int)key;
 946 }
 947 
 948 // Note: This is currently not used by VM, as we don't destroy TLS key
 949 // on VM exit.
 950 void os::free_thread_local_storage(int index) {
 951   int rslt = pthread_key_delete((pthread_key_t)index);
 952   assert(rslt == 0, "invalid index");
 953 }
 954 
 955 void os::thread_local_storage_at_put(int index, void* value) {
 956   int rslt = pthread_setspecific((pthread_key_t)index, value);
 957   assert(rslt == 0, "pthread_setspecific failed");
 958 }
 959 
 960 extern "C" Thread* get_thread() {
 961   return ThreadLocalStorage::thread();
 962 }
 963 
 964 
 965 ////////////////////////////////////////////////////////////////////////////////
 966 // time support
 967 
 968 // Time since start-up in seconds to a fine granularity.
 969 // Used by VMSelfDestructTimer and the MemProfiler.
 970 double os::elapsedTime() {
 971 
 972   return ((double)os::elapsed_counter()) / os::elapsed_frequency();
 973 }
 974 
 975 jlong os::elapsed_counter() {
 976   return javaTimeNanos() - initial_time_count;
 977 }
 978 
 979 jlong os::elapsed_frequency() {
 980   return NANOSECS_PER_SEC; // nanosecond resolution
 981 }
 982 
 983 bool os::supports_vtime() { return true; }
 984 bool os::enable_vtime()   { return false; }
 985 bool os::vtime_enabled()  { return false; }
 986 
 987 double os::elapsedVTime() {
 988   // better than nothing, but not much
 989   return elapsedTime();
 990 }
 991 
 992 jlong os::javaTimeMillis() {
 993   timeval time;
 994   int status = gettimeofday(&time, NULL);
 995   assert(status != -1, "bsd error");
 996   return jlong(time.tv_sec) * 1000  +  jlong(time.tv_usec / 1000);
 997 }
 998 
 999 #ifndef __APPLE__
1000 #ifndef CLOCK_MONOTONIC
1001 #define CLOCK_MONOTONIC (1)
1002 #endif
1003 #endif
1004 
1005 #ifdef __APPLE__
1006 void os::Bsd::clock_init() {
1007   mach_timebase_info(&_timebase_info);
1008 }
1009 #else
1010 void os::Bsd::clock_init() {
1011   struct timespec res;
1012   struct timespec tp;
1013   if (::clock_getres(CLOCK_MONOTONIC, &res) == 0 &&
1014       ::clock_gettime(CLOCK_MONOTONIC, &tp)  == 0) {
1015     // yes, monotonic clock is supported
1016     _clock_gettime = ::clock_gettime;
1017   }
1018 }
1019 #endif
1020 
1021 
1022 
1023 #ifdef __APPLE__
1024 
1025 jlong os::javaTimeNanos() {
1026     const uint64_t tm = mach_absolute_time();
1027     const uint64_t now = (tm * Bsd::_timebase_info.numer) / Bsd::_timebase_info.denom;
1028     const uint64_t prev = Bsd::_max_abstime;
1029     if (now <= prev) {
1030       return prev;   // same or retrograde time;
1031     }
1032     const uint64_t obsv = Atomic::cmpxchg(now, (volatile jlong*)&Bsd::_max_abstime, prev);
1033     assert(obsv >= prev, "invariant");   // Monotonicity
1034     // If the CAS succeeded then we're done and return "now".
1035     // If the CAS failed and the observed value "obsv" is >= now then
1036     // we should return "obsv".  If the CAS failed and now > obsv > prv then
1037     // some other thread raced this thread and installed a new value, in which case
1038     // we could either (a) retry the entire operation, (b) retry trying to install now
1039     // or (c) just return obsv.  We use (c).   No loop is required although in some cases
1040     // we might discard a higher "now" value in deference to a slightly lower but freshly
1041     // installed obsv value.   That's entirely benign -- it admits no new orderings compared
1042     // to (a) or (b) -- and greatly reduces coherence traffic.
1043     // We might also condition (c) on the magnitude of the delta between obsv and now.
1044     // Avoiding excessive CAS operations to hot RW locations is critical.
1045     // See https://blogs.oracle.com/dave/entry/cas_and_cache_trivia_invalidate
1046     return (prev == obsv) ? now : obsv;
1047 }
1048 
1049 #else // __APPLE__
1050 
1051 jlong os::javaTimeNanos() {
1052   if (os::supports_monotonic_clock()) {
1053     struct timespec tp;
1054     int status = Bsd::_clock_gettime(CLOCK_MONOTONIC, &tp);
1055     assert(status == 0, "gettime error");
1056     jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1057     return result;
1058   } else {
1059     timeval time;
1060     int status = gettimeofday(&time, NULL);
1061     assert(status != -1, "bsd error");
1062     jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1063     return 1000 * usecs;
1064   }
1065 }
1066 
1067 #endif // __APPLE__
1068 
1069 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1070   if (os::supports_monotonic_clock()) {
1071     info_ptr->max_value = ALL_64_BITS;
1072 
1073     // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1074     info_ptr->may_skip_backward = false;      // not subject to resetting or drifting
1075     info_ptr->may_skip_forward = false;       // not subject to resetting or drifting
1076   } else {
1077     // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1078     info_ptr->max_value = ALL_64_BITS;
1079 
1080     // gettimeofday is a real time clock so it skips
1081     info_ptr->may_skip_backward = true;
1082     info_ptr->may_skip_forward = true;
1083   }
1084 
1085   info_ptr->kind = JVMTI_TIMER_ELAPSED;                // elapsed not CPU time
1086 }
1087 
1088 // Return the real, user, and system times in seconds from an
1089 // arbitrary fixed point in the past.
1090 bool os::getTimesSecs(double* process_real_time,
1091                       double* process_user_time,
1092                       double* process_system_time) {
1093   struct tms ticks;
1094   clock_t real_ticks = times(&ticks);
1095 
1096   if (real_ticks == (clock_t) (-1)) {
1097     return false;
1098   } else {
1099     double ticks_per_second = (double) clock_tics_per_sec;
1100     *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1101     *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1102     *process_real_time = ((double) real_ticks) / ticks_per_second;
1103 
1104     return true;
1105   }
1106 }
1107 
1108 
1109 char * os::local_time_string(char *buf, size_t buflen) {
1110   struct tm t;
1111   time_t long_time;
1112   time(&long_time);
1113   localtime_r(&long_time, &t);
1114   jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1115                t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1116                t.tm_hour, t.tm_min, t.tm_sec);
1117   return buf;
1118 }
1119 
1120 struct tm* os::localtime_pd(const time_t* clock, struct tm*  res) {
1121   return localtime_r(clock, res);
1122 }
1123 
1124 ////////////////////////////////////////////////////////////////////////////////
1125 // runtime exit support
1126 
1127 // Note: os::shutdown() might be called very early during initialization, or
1128 // called from signal handler. Before adding something to os::shutdown(), make
1129 // sure it is async-safe and can handle partially initialized VM.
1130 void os::shutdown() {
1131 
1132   // allow PerfMemory to attempt cleanup of any persistent resources
1133   perfMemory_exit();
1134 
1135   // needs to remove object in file system
1136   AttachListener::abort();
1137 
1138   // flush buffered output, finish log files
1139   ostream_abort();
1140 
1141   // Check for abort hook
1142   abort_hook_t abort_hook = Arguments::abort_hook();
1143   if (abort_hook != NULL) {
1144     abort_hook();
1145   }
1146 
1147 }
1148 
1149 // Note: os::abort() might be called very early during initialization, or
1150 // called from signal handler. Before adding something to os::abort(), make
1151 // sure it is async-safe and can handle partially initialized VM.
1152 void os::abort(bool dump_core) {
1153   os::shutdown();
1154   if (dump_core) {
1155 #ifndef PRODUCT
1156     fdStream out(defaultStream::output_fd());
1157     out.print_raw("Current thread is ");
1158     char buf[16];
1159     jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1160     out.print_raw_cr(buf);
1161     out.print_raw_cr("Dumping core ...");
1162 #endif
1163     ::abort(); // dump core
1164   }
1165 
1166   ::exit(1);
1167 }
1168 
1169 // Die immediately, no exit hook, no abort hook, no cleanup.
1170 void os::die() {
1171   // _exit() on BsdThreads only kills current thread
1172   ::abort();
1173 }
1174 
1175 // This method is a copy of JDK's sysGetLastErrorString
1176 // from src/solaris/hpi/src/system_md.c
1177 
1178 size_t os::lasterror(char *buf, size_t len) {
1179 
1180   if (errno == 0)  return 0;
1181 
1182   const char *s = ::strerror(errno);
1183   size_t n = ::strlen(s);
1184   if (n >= len) {
1185     n = len - 1;
1186   }
1187   ::strncpy(buf, s, n);
1188   buf[n] = '\0';
1189   return n;
1190 }
1191 
1192 // Information of current thread in variety of formats
1193 pid_t os::Bsd::gettid() {
1194   int retval = -1;
1195 
1196 #ifdef __APPLE__ //XNU kernel
1197   // despite the fact mach port is actually not a thread id use it
1198   // instead of syscall(SYS_thread_selfid) as it certainly fits to u4
1199   retval = ::pthread_mach_thread_np(::pthread_self());
1200   guarantee(retval != 0, "just checking");
1201   return retval;
1202 
1203 #elif __FreeBSD__
1204   retval = syscall(SYS_thr_self);
1205 #elif __OpenBSD__
1206   retval = syscall(SYS_getthrid);
1207 #elif __NetBSD__
1208   retval = (pid_t) syscall(SYS__lwp_self);
1209 #endif
1210 
1211   if (retval == -1) {
1212     return getpid();
1213   }
1214 }
1215 
1216 intx os::current_thread_id() {
1217 #ifdef __APPLE__
1218   return (intx)::pthread_mach_thread_np(::pthread_self());
1219 #else
1220   return (intx)::pthread_self();
1221 #endif
1222 }
1223 
1224 int os::current_process_id() {
1225 
1226   // Under the old bsd thread library, bsd gives each thread
1227   // its own process id. Because of this each thread will return
1228   // a different pid if this method were to return the result
1229   // of getpid(2). Bsd provides no api that returns the pid
1230   // of the launcher thread for the vm. This implementation
1231   // returns a unique pid, the pid of the launcher thread
1232   // that starts the vm 'process'.
1233 
1234   // Under the NPTL, getpid() returns the same pid as the
1235   // launcher thread rather than a unique pid per thread.
1236   // Use gettid() if you want the old pre NPTL behaviour.
1237 
1238   // if you are looking for the result of a call to getpid() that
1239   // returns a unique pid for the calling thread, then look at the
1240   // OSThread::thread_id() method in osThread_bsd.hpp file
1241 
1242   return (int)(_initial_pid ? _initial_pid : getpid());
1243 }
1244 
1245 // DLL functions
1246 
1247 #define JNI_LIB_PREFIX "lib"
1248 #ifdef __APPLE__
1249 #define JNI_LIB_SUFFIX ".dylib"
1250 #else
1251 #define JNI_LIB_SUFFIX ".so"
1252 #endif
1253 
1254 const char* os::dll_file_extension() { return JNI_LIB_SUFFIX; }
1255 
1256 // This must be hard coded because it's the system's temporary
1257 // directory not the java application's temp directory, ala java.io.tmpdir.
1258 #ifdef __APPLE__
1259 // macosx has a secure per-user temporary directory
1260 char temp_path_storage[PATH_MAX];
1261 const char* os::get_temp_directory() {
1262   static char *temp_path = NULL;
1263   if (temp_path == NULL) {
1264     int pathSize = confstr(_CS_DARWIN_USER_TEMP_DIR, temp_path_storage, PATH_MAX);
1265     if (pathSize == 0 || pathSize > PATH_MAX) {
1266       strlcpy(temp_path_storage, "/tmp/", sizeof(temp_path_storage));
1267     }
1268     temp_path = temp_path_storage;
1269   }
1270   return temp_path;
1271 }
1272 #else /* __APPLE__ */
1273 const char* os::get_temp_directory() { return "/tmp"; }
1274 #endif /* __APPLE__ */
1275 
1276 static bool file_exists(const char* filename) {
1277   struct stat statbuf;
1278   if (filename == NULL || strlen(filename) == 0) {
1279     return false;
1280   }
1281   return os::stat(filename, &statbuf) == 0;
1282 }
1283 
1284 bool os::dll_build_name(char* buffer, size_t buflen,
1285                         const char* pname, const char* fname) {
1286   bool retval = false;
1287   // Copied from libhpi
1288   const size_t pnamelen = pname ? strlen(pname) : 0;
1289 
1290   // Return error on buffer overflow.
1291   if (pnamelen + strlen(fname) + strlen(JNI_LIB_PREFIX) + strlen(JNI_LIB_SUFFIX) + 2 > buflen) {
1292     return retval;
1293   }
1294 
1295   if (pnamelen == 0) {
1296     snprintf(buffer, buflen, JNI_LIB_PREFIX "%s" JNI_LIB_SUFFIX, fname);
1297     retval = true;
1298   } else if (strchr(pname, *os::path_separator()) != NULL) {
1299     int n;
1300     char** pelements = split_path(pname, &n);
1301     if (pelements == NULL) {
1302       return false;
1303     }
1304     for (int i = 0; i < n; i++) {
1305       // Really shouldn't be NULL, but check can't hurt
1306       if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1307         continue; // skip the empty path values
1308       }
1309       snprintf(buffer, buflen, "%s/" JNI_LIB_PREFIX "%s" JNI_LIB_SUFFIX,
1310           pelements[i], fname);
1311       if (file_exists(buffer)) {
1312         retval = true;
1313         break;
1314       }
1315     }
1316     // release the storage
1317     for (int i = 0; i < n; i++) {
1318       if (pelements[i] != NULL) {
1319         FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal);
1320       }
1321     }
1322     if (pelements != NULL) {
1323       FREE_C_HEAP_ARRAY(char*, pelements, mtInternal);
1324     }
1325   } else {
1326     snprintf(buffer, buflen, "%s/" JNI_LIB_PREFIX "%s" JNI_LIB_SUFFIX, pname, fname);
1327     retval = true;
1328   }
1329   return retval;
1330 }
1331 
1332 // check if addr is inside libjvm.so
1333 bool os::address_is_in_vm(address addr) {
1334   static address libjvm_base_addr;
1335   Dl_info dlinfo;
1336 
1337   if (libjvm_base_addr == NULL) {
1338     if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1339       libjvm_base_addr = (address)dlinfo.dli_fbase;
1340     }
1341     assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1342   }
1343 
1344   if (dladdr((void *)addr, &dlinfo) != 0) {
1345     if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1346   }
1347 
1348   return false;
1349 }
1350 
1351 
1352 #define MACH_MAXSYMLEN 256
1353 
1354 bool os::dll_address_to_function_name(address addr, char *buf,
1355                                       int buflen, int *offset) {
1356   // buf is not optional, but offset is optional
1357   assert(buf != NULL, "sanity check");
1358 
1359   Dl_info dlinfo;
1360   char localbuf[MACH_MAXSYMLEN];
1361 
1362   if (dladdr((void*)addr, &dlinfo) != 0) {
1363     // see if we have a matching symbol
1364     if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1365       if (!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1366         jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1367       }
1368       if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1369       return true;
1370     }
1371     // no matching symbol so try for just file info
1372     if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1373       if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1374                           buf, buflen, offset, dlinfo.dli_fname)) {
1375          return true;
1376       }
1377     }
1378 
1379     // Handle non-dynamic manually:
1380     if (dlinfo.dli_fbase != NULL &&
1381         Decoder::decode(addr, localbuf, MACH_MAXSYMLEN, offset,
1382                         dlinfo.dli_fbase)) {
1383       if (!Decoder::demangle(localbuf, buf, buflen)) {
1384         jio_snprintf(buf, buflen, "%s", localbuf);
1385       }
1386       return true;
1387     }
1388   }
1389   buf[0] = '\0';
1390   if (offset != NULL) *offset = -1;
1391   return false;
1392 }
1393 
1394 // ported from solaris version
1395 bool os::dll_address_to_library_name(address addr, char* buf,
1396                                      int buflen, int* offset) {
1397   // buf is not optional, but offset is optional
1398   assert(buf != NULL, "sanity check");
1399 
1400   Dl_info dlinfo;
1401 
1402   if (dladdr((void*)addr, &dlinfo) != 0) {
1403     if (dlinfo.dli_fname != NULL) {
1404       jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1405     }
1406     if (dlinfo.dli_fbase != NULL && offset != NULL) {
1407       *offset = addr - (address)dlinfo.dli_fbase;
1408     }
1409     return true;
1410   }
1411 
1412   buf[0] = '\0';
1413   if (offset) *offset = -1;
1414   return false;
1415 }
1416 
1417 // Loads .dll/.so and
1418 // in case of error it checks if .dll/.so was built for the
1419 // same architecture as Hotspot is running on
1420 
1421 #ifdef __APPLE__
1422 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1423   void * result= ::dlopen(filename, RTLD_LAZY);
1424   if (result != NULL) {
1425     // Successful loading
1426     return result;
1427   }
1428 
1429   // Read system error message into ebuf
1430   ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1431   ebuf[ebuflen-1]='\0';
1432 
1433   return NULL;
1434 }
1435 #else
1436 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1437 {
1438   void * result= ::dlopen(filename, RTLD_LAZY);
1439   if (result != NULL) {
1440     // Successful loading
1441     return result;
1442   }
1443 
1444   Elf32_Ehdr elf_head;
1445 
1446   // Read system error message into ebuf
1447   // It may or may not be overwritten below
1448   ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1449   ebuf[ebuflen-1]='\0';
1450   int diag_msg_max_length=ebuflen-strlen(ebuf);
1451   char* diag_msg_buf=ebuf+strlen(ebuf);
1452 
1453   if (diag_msg_max_length==0) {
1454     // No more space in ebuf for additional diagnostics message
1455     return NULL;
1456   }
1457 
1458 
1459   int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1460 
1461   if (file_descriptor < 0) {
1462     // Can't open library, report dlerror() message
1463     return NULL;
1464   }
1465 
1466   bool failed_to_read_elf_head=
1467     (sizeof(elf_head)!=
1468         (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1469 
1470   ::close(file_descriptor);
1471   if (failed_to_read_elf_head) {
1472     // file i/o error - report dlerror() msg
1473     return NULL;
1474   }
1475 
1476   typedef struct {
1477     Elf32_Half  code;         // Actual value as defined in elf.h
1478     Elf32_Half  compat_class; // Compatibility of archs at VM's sense
1479     char        elf_class;    // 32 or 64 bit
1480     char        endianess;    // MSB or LSB
1481     char*       name;         // String representation
1482   } arch_t;
1483 
1484   #ifndef EM_486
1485   #define EM_486          6               /* Intel 80486 */
1486   #endif
1487 
1488   #ifndef EM_MIPS_RS3_LE
1489   #define EM_MIPS_RS3_LE  10              /* MIPS */
1490   #endif
1491 
1492   #ifndef EM_PPC64
1493   #define EM_PPC64        21              /* PowerPC64 */
1494   #endif
1495 
1496   #ifndef EM_S390
1497   #define EM_S390         22              /* IBM System/390 */
1498   #endif
1499 
1500   #ifndef EM_IA_64
1501   #define EM_IA_64        50              /* HP/Intel IA-64 */
1502   #endif
1503 
1504   #ifndef EM_X86_64
1505   #define EM_X86_64       62              /* AMD x86-64 */
1506   #endif
1507 
1508   static const arch_t arch_array[]={
1509     {EM_386,         EM_386,     ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1510     {EM_486,         EM_386,     ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1511     {EM_IA_64,       EM_IA_64,   ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1512     {EM_X86_64,      EM_X86_64,  ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1513     {EM_SPARC,       EM_SPARC,   ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1514     {EM_SPARC32PLUS, EM_SPARC,   ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1515     {EM_SPARCV9,     EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1516     {EM_PPC,         EM_PPC,     ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1517     {EM_PPC64,       EM_PPC64,   ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1518     {EM_ARM,         EM_ARM,     ELFCLASS32,   ELFDATA2LSB, (char*)"ARM"},
1519     {EM_S390,        EM_S390,    ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1520     {EM_ALPHA,       EM_ALPHA,   ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1521     {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1522     {EM_MIPS,        EM_MIPS,    ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1523     {EM_PARISC,      EM_PARISC,  ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1524     {EM_68K,         EM_68K,     ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1525   };
1526 
1527   #if  (defined IA32)
1528     static  Elf32_Half running_arch_code=EM_386;
1529   #elif   (defined AMD64)
1530     static  Elf32_Half running_arch_code=EM_X86_64;
1531   #elif  (defined IA64)
1532     static  Elf32_Half running_arch_code=EM_IA_64;
1533   #elif  (defined __sparc) && (defined _LP64)
1534     static  Elf32_Half running_arch_code=EM_SPARCV9;
1535   #elif  (defined __sparc) && (!defined _LP64)
1536     static  Elf32_Half running_arch_code=EM_SPARC;
1537   #elif  (defined __powerpc64__)
1538     static  Elf32_Half running_arch_code=EM_PPC64;
1539   #elif  (defined __powerpc__)
1540     static  Elf32_Half running_arch_code=EM_PPC;
1541   #elif  (defined ARM)
1542     static  Elf32_Half running_arch_code=EM_ARM;
1543   #elif  (defined S390)
1544     static  Elf32_Half running_arch_code=EM_S390;
1545   #elif  (defined ALPHA)
1546     static  Elf32_Half running_arch_code=EM_ALPHA;
1547   #elif  (defined MIPSEL)
1548     static  Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1549   #elif  (defined PARISC)
1550     static  Elf32_Half running_arch_code=EM_PARISC;
1551   #elif  (defined MIPS)
1552     static  Elf32_Half running_arch_code=EM_MIPS;
1553   #elif  (defined M68K)
1554     static  Elf32_Half running_arch_code=EM_68K;
1555   #else
1556     #error Method os::dll_load requires that one of following is defined:\
1557          IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1558   #endif
1559 
1560   // Identify compatability class for VM's architecture and library's architecture
1561   // Obtain string descriptions for architectures
1562 
1563   arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1564   int running_arch_index=-1;
1565 
1566   for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1567     if (running_arch_code == arch_array[i].code) {
1568       running_arch_index    = i;
1569     }
1570     if (lib_arch.code == arch_array[i].code) {
1571       lib_arch.compat_class = arch_array[i].compat_class;
1572       lib_arch.name         = arch_array[i].name;
1573     }
1574   }
1575 
1576   assert(running_arch_index != -1,
1577     "Didn't find running architecture code (running_arch_code) in arch_array");
1578   if (running_arch_index == -1) {
1579     // Even though running architecture detection failed
1580     // we may still continue with reporting dlerror() message
1581     return NULL;
1582   }
1583 
1584   if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1585     ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1586     return NULL;
1587   }
1588 
1589 #ifndef S390
1590   if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1591     ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1592     return NULL;
1593   }
1594 #endif // !S390
1595 
1596   if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1597     if (lib_arch.name!=NULL) {
1598       ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1599         " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1600         lib_arch.name, arch_array[running_arch_index].name);
1601     } else {
1602       ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1603       " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1604         lib_arch.code,
1605         arch_array[running_arch_index].name);
1606     }
1607   }
1608 
1609   return NULL;
1610 }
1611 #endif /* !__APPLE__ */
1612 
1613 void* os::get_default_process_handle() {
1614 #ifdef __APPLE__
1615   // MacOS X needs to use RTLD_FIRST instead of RTLD_LAZY
1616   // to avoid finding unexpected symbols on second (or later)
1617   // loads of a library.
1618   return (void*)::dlopen(NULL, RTLD_FIRST);
1619 #else
1620   return (void*)::dlopen(NULL, RTLD_LAZY);
1621 #endif
1622 }
1623 
1624 // XXX: Do we need a lock around this as per Linux?
1625 void* os::dll_lookup(void* handle, const char* name) {
1626   return dlsym(handle, name);
1627 }
1628 
1629 
1630 static bool _print_ascii_file(const char* filename, outputStream* st) {
1631   int fd = ::open(filename, O_RDONLY);
1632   if (fd == -1) {
1633      return false;
1634   }
1635 
1636   char buf[32];
1637   int bytes;
1638   while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
1639     st->print_raw(buf, bytes);
1640   }
1641 
1642   ::close(fd);
1643 
1644   return true;
1645 }
1646 
1647 void os::print_dll_info(outputStream *st) {
1648   st->print_cr("Dynamic libraries:");
1649 #ifdef RTLD_DI_LINKMAP
1650   Dl_info dli;
1651   void *handle;
1652   Link_map *map;
1653   Link_map *p;
1654 
1655   if (dladdr(CAST_FROM_FN_PTR(void *, os::print_dll_info), &dli) == 0 ||
1656       dli.dli_fname == NULL) {
1657     st->print_cr("Error: Cannot print dynamic libraries.");
1658     return;
1659   }
1660   handle = dlopen(dli.dli_fname, RTLD_LAZY);
1661   if (handle == NULL) {
1662     st->print_cr("Error: Cannot print dynamic libraries.");
1663     return;
1664   }
1665   dlinfo(handle, RTLD_DI_LINKMAP, &map);
1666   if (map == NULL) {
1667     st->print_cr("Error: Cannot print dynamic libraries.");
1668     return;
1669   }
1670 
1671   while (map->l_prev != NULL)
1672     map = map->l_prev;
1673 
1674   while (map != NULL) {
1675     st->print_cr(PTR_FORMAT " \t%s", map->l_addr, map->l_name);
1676     map = map->l_next;
1677   }
1678 
1679   dlclose(handle);
1680 #elif defined(__APPLE__)
1681   for (uint32_t i = 1; i < _dyld_image_count(); i++) {
1682     st->print_cr(PTR_FORMAT " \t%s", _dyld_get_image_header(i),
1683         _dyld_get_image_name(i));
1684   }
1685 #else
1686   st->print_cr("Error: Cannot print dynamic libraries.");
1687 #endif
1688 }
1689 
1690 void os::print_os_info_brief(outputStream* st) {
1691   st->print("Bsd");
1692 
1693   os::Posix::print_uname_info(st);
1694 }
1695 
1696 void os::print_os_info(outputStream* st) {
1697   st->print("OS:");
1698   st->print("Bsd");
1699 
1700   os::Posix::print_uname_info(st);
1701 
1702   os::Posix::print_rlimit_info(st);
1703 
1704   os::Posix::print_load_average(st);
1705 }
1706 
1707 void os::pd_print_cpu_info(outputStream* st) {
1708   // Nothing to do for now.
1709 }
1710 
1711 void os::print_memory_info(outputStream* st) {
1712 
1713   st->print("Memory:");
1714   st->print(" %dk page", os::vm_page_size()>>10);
1715 
1716   st->print(", physical " UINT64_FORMAT "k",
1717             os::physical_memory() >> 10);
1718   st->print("(" UINT64_FORMAT "k free)",
1719             os::available_memory() >> 10);
1720   st->cr();
1721 
1722   // meminfo
1723   st->print("\n/proc/meminfo:\n");
1724   _print_ascii_file("/proc/meminfo", st);
1725   st->cr();
1726 }
1727 
1728 void os::print_siginfo(outputStream* st, void* siginfo) {
1729   const siginfo_t* si = (const siginfo_t*)siginfo;
1730 
1731   os::Posix::print_siginfo_brief(st, si);
1732 
1733   if (si && (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
1734       UseSharedSpaces) {
1735     FileMapInfo* mapinfo = FileMapInfo::current_info();
1736     if (mapinfo->is_in_shared_space(si->si_addr)) {
1737       st->print("\n\nError accessing class data sharing archive."   \
1738                 " Mapped file inaccessible during execution, "      \
1739                 " possible disk/network problem.");
1740     }
1741   }
1742   st->cr();
1743 }
1744 
1745 
1746 static void print_signal_handler(outputStream* st, int sig,
1747                                  char* buf, size_t buflen);
1748 
1749 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
1750   st->print_cr("Signal Handlers:");
1751   print_signal_handler(st, SIGSEGV, buf, buflen);
1752   print_signal_handler(st, SIGBUS , buf, buflen);
1753   print_signal_handler(st, SIGFPE , buf, buflen);
1754   print_signal_handler(st, SIGPIPE, buf, buflen);
1755   print_signal_handler(st, SIGXFSZ, buf, buflen);
1756   print_signal_handler(st, SIGILL , buf, buflen);
1757   print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
1758   print_signal_handler(st, SR_signum, buf, buflen);
1759   print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
1760   print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
1761   print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
1762   print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
1763 }
1764 
1765 static char saved_jvm_path[MAXPATHLEN] = {0};
1766 
1767 // Find the full path to the current module, libjvm
1768 void os::jvm_path(char *buf, jint buflen) {
1769   // Error checking.
1770   if (buflen < MAXPATHLEN) {
1771     assert(false, "must use a large-enough buffer");
1772     buf[0] = '\0';
1773     return;
1774   }
1775   // Lazy resolve the path to current module.
1776   if (saved_jvm_path[0] != 0) {
1777     strcpy(buf, saved_jvm_path);
1778     return;
1779   }
1780 
1781   char dli_fname[MAXPATHLEN];
1782   bool ret = dll_address_to_library_name(
1783                 CAST_FROM_FN_PTR(address, os::jvm_path),
1784                 dli_fname, sizeof(dli_fname), NULL);
1785   assert(ret, "cannot locate libjvm");
1786   char *rp = NULL;
1787   if (ret && dli_fname[0] != '\0') {
1788     rp = realpath(dli_fname, buf);
1789   }
1790   if (rp == NULL)
1791     return;
1792 
1793   if (Arguments::sun_java_launcher_is_altjvm()) {
1794     // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
1795     // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so"
1796     // or "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.dylib". If "/jre/lib/"
1797     // appears at the right place in the string, then assume we are
1798     // installed in a JDK and we're done. Otherwise, check for a
1799     // JAVA_HOME environment variable and construct a path to the JVM
1800     // being overridden.
1801 
1802     const char *p = buf + strlen(buf) - 1;
1803     for (int count = 0; p > buf && count < 5; ++count) {
1804       for (--p; p > buf && *p != '/'; --p)
1805         /* empty */ ;
1806     }
1807 
1808     if (strncmp(p, "/jre/lib/", 9) != 0) {
1809       // Look for JAVA_HOME in the environment.
1810       char* java_home_var = ::getenv("JAVA_HOME");
1811       if (java_home_var != NULL && java_home_var[0] != 0) {
1812         char* jrelib_p;
1813         int len;
1814 
1815         // Check the current module name "libjvm"
1816         p = strrchr(buf, '/');
1817         assert(strstr(p, "/libjvm") == p, "invalid library name");
1818 
1819         rp = realpath(java_home_var, buf);
1820         if (rp == NULL)
1821           return;
1822 
1823         // determine if this is a legacy image or modules image
1824         // modules image doesn't have "jre" subdirectory
1825         len = strlen(buf);
1826         assert(len < buflen, "Ran out of buffer space");
1827         jrelib_p = buf + len;
1828 
1829         // Add the appropriate library subdir
1830         snprintf(jrelib_p, buflen-len, "/jre/lib");
1831         if (0 != access(buf, F_OK)) {
1832           snprintf(jrelib_p, buflen-len, "/lib");
1833         }
1834 
1835         // Add the appropriate client or server subdir
1836         len = strlen(buf);
1837         jrelib_p = buf + len;
1838         snprintf(jrelib_p, buflen-len, "/%s", COMPILER_VARIANT);
1839         if (0 != access(buf, F_OK)) {
1840           snprintf(jrelib_p, buflen-len, "%s", "");
1841         }
1842 
1843         // If the path exists within JAVA_HOME, add the JVM library name
1844         // to complete the path to JVM being overridden.  Otherwise fallback
1845         // to the path to the current library.
1846         if (0 == access(buf, F_OK)) {
1847           // Use current module name "libjvm"
1848           len = strlen(buf);
1849           snprintf(buf + len, buflen-len, "/libjvm%s", JNI_LIB_SUFFIX);
1850         } else {
1851           // Fall back to path of current library
1852           rp = realpath(dli_fname, buf);
1853           if (rp == NULL)
1854             return;
1855         }
1856       }
1857     }
1858   }
1859 
1860   strncpy(saved_jvm_path, buf, MAXPATHLEN);
1861 }
1862 
1863 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
1864   // no prefix required, not even "_"
1865 }
1866 
1867 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
1868   // no suffix required
1869 }
1870 
1871 ////////////////////////////////////////////////////////////////////////////////
1872 // sun.misc.Signal support
1873 
1874 static volatile jint sigint_count = 0;
1875 
1876 static void
1877 UserHandler(int sig, void *siginfo, void *context) {
1878   // 4511530 - sem_post is serialized and handled by the manager thread. When
1879   // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
1880   // don't want to flood the manager thread with sem_post requests.
1881   if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
1882       return;
1883 
1884   // Ctrl-C is pressed during error reporting, likely because the error
1885   // handler fails to abort. Let VM die immediately.
1886   if (sig == SIGINT && is_error_reported()) {
1887      os::die();
1888   }
1889 
1890   os::signal_notify(sig);
1891 }
1892 
1893 void* os::user_handler() {
1894   return CAST_FROM_FN_PTR(void*, UserHandler);
1895 }
1896 
1897 extern "C" {
1898   typedef void (*sa_handler_t)(int);
1899   typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
1900 }
1901 
1902 void* os::signal(int signal_number, void* handler) {
1903   struct sigaction sigAct, oldSigAct;
1904 
1905   sigfillset(&(sigAct.sa_mask));
1906   sigAct.sa_flags   = SA_RESTART|SA_SIGINFO;
1907   sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
1908 
1909   if (sigaction(signal_number, &sigAct, &oldSigAct)) {
1910     // -1 means registration failed
1911     return (void *)-1;
1912   }
1913 
1914   return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
1915 }
1916 
1917 void os::signal_raise(int signal_number) {
1918   ::raise(signal_number);
1919 }
1920 
1921 /*
1922  * The following code is moved from os.cpp for making this
1923  * code platform specific, which it is by its very nature.
1924  */
1925 
1926 // Will be modified when max signal is changed to be dynamic
1927 int os::sigexitnum_pd() {
1928   return NSIG;
1929 }
1930 
1931 // a counter for each possible signal value
1932 static volatile jint pending_signals[NSIG+1] = { 0 };
1933 
1934 // Bsd(POSIX) specific hand shaking semaphore.
1935 #ifdef __APPLE__
1936 typedef semaphore_t os_semaphore_t;
1937 #define SEM_INIT(sem, value)    semaphore_create(mach_task_self(), &sem, SYNC_POLICY_FIFO, value)
1938 #define SEM_WAIT(sem)           semaphore_wait(sem)
1939 #define SEM_POST(sem)           semaphore_signal(sem)
1940 #define SEM_DESTROY(sem)        semaphore_destroy(mach_task_self(), sem)
1941 #else
1942 typedef sem_t os_semaphore_t;
1943 #define SEM_INIT(sem, value)    sem_init(&sem, 0, value)
1944 #define SEM_WAIT(sem)           sem_wait(&sem)
1945 #define SEM_POST(sem)           sem_post(&sem)
1946 #define SEM_DESTROY(sem)        sem_destroy(&sem)
1947 #endif
1948 
1949 class Semaphore : public StackObj {
1950   public:
1951     Semaphore();
1952     ~Semaphore();
1953     void signal();
1954     void wait();
1955     bool trywait();
1956     bool timedwait(unsigned int sec, int nsec);
1957   private:
1958     jlong currenttime() const;
1959     os_semaphore_t _semaphore;
1960 };
1961 
1962 Semaphore::Semaphore() : _semaphore(0) {
1963   SEM_INIT(_semaphore, 0);
1964 }
1965 
1966 Semaphore::~Semaphore() {
1967   SEM_DESTROY(_semaphore);
1968 }
1969 
1970 void Semaphore::signal() {
1971   SEM_POST(_semaphore);
1972 }
1973 
1974 void Semaphore::wait() {
1975   SEM_WAIT(_semaphore);
1976 }
1977 
1978 jlong Semaphore::currenttime() const {
1979     struct timeval tv;
1980     gettimeofday(&tv, NULL);
1981     return (tv.tv_sec * NANOSECS_PER_SEC) + (tv.tv_usec * 1000);
1982 }
1983 
1984 #ifdef __APPLE__
1985 bool Semaphore::trywait() {
1986   return timedwait(0, 0);
1987 }
1988 
1989 bool Semaphore::timedwait(unsigned int sec, int nsec) {
1990   kern_return_t kr = KERN_ABORTED;
1991   mach_timespec_t waitspec;
1992   waitspec.tv_sec = sec;
1993   waitspec.tv_nsec = nsec;
1994 
1995   jlong starttime = currenttime();
1996 
1997   kr = semaphore_timedwait(_semaphore, waitspec);
1998   while (kr == KERN_ABORTED) {
1999     jlong totalwait = (sec * NANOSECS_PER_SEC) + nsec;
2000 
2001     jlong current = currenttime();
2002     jlong passedtime = current - starttime;
2003 
2004     if (passedtime >= totalwait) {
2005       waitspec.tv_sec = 0;
2006       waitspec.tv_nsec = 0;
2007     } else {
2008       jlong waittime = totalwait - (current - starttime);
2009       waitspec.tv_sec = waittime / NANOSECS_PER_SEC;
2010       waitspec.tv_nsec = waittime % NANOSECS_PER_SEC;
2011     }
2012 
2013     kr = semaphore_timedwait(_semaphore, waitspec);
2014   }
2015 
2016   return kr == KERN_SUCCESS;
2017 }
2018 
2019 #else
2020 
2021 bool Semaphore::trywait() {
2022   return sem_trywait(&_semaphore) == 0;
2023 }
2024 
2025 bool Semaphore::timedwait(unsigned int sec, int nsec) {
2026   struct timespec ts;
2027   unpackTime(&ts, false, (sec * NANOSECS_PER_SEC) + nsec);
2028 
2029   while (1) {
2030     int result = sem_timedwait(&_semaphore, &ts);
2031     if (result == 0) {
2032       return true;
2033     } else if (errno == EINTR) {
2034       continue;
2035     } else if (errno == ETIMEDOUT) {
2036       return false;
2037     } else {
2038       return false;
2039     }
2040   }
2041 }
2042 
2043 #endif // __APPLE__
2044 
2045 static os_semaphore_t sig_sem;
2046 static Semaphore sr_semaphore;
2047 
2048 void os::signal_init_pd() {
2049   // Initialize signal structures
2050   ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2051 
2052   // Initialize signal semaphore
2053   ::SEM_INIT(sig_sem, 0);
2054 }
2055 
2056 void os::signal_notify(int sig) {
2057   Atomic::inc(&pending_signals[sig]);
2058   ::SEM_POST(sig_sem);
2059 }
2060 
2061 static int check_pending_signals(bool wait) {
2062   Atomic::store(0, &sigint_count);
2063   for (;;) {
2064     for (int i = 0; i < NSIG + 1; i++) {
2065       jint n = pending_signals[i];
2066       if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2067         return i;
2068       }
2069     }
2070     if (!wait) {
2071       return -1;
2072     }
2073     JavaThread *thread = JavaThread::current();
2074     ThreadBlockInVM tbivm(thread);
2075 
2076     bool threadIsSuspended;
2077     do {
2078       thread->set_suspend_equivalent();
2079       // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2080       ::SEM_WAIT(sig_sem);
2081 
2082       // were we externally suspended while we were waiting?
2083       threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2084       if (threadIsSuspended) {
2085         //
2086         // The semaphore has been incremented, but while we were waiting
2087         // another thread suspended us. We don't want to continue running
2088         // while suspended because that would surprise the thread that
2089         // suspended us.
2090         //
2091         ::SEM_POST(sig_sem);
2092 
2093         thread->java_suspend_self();
2094       }
2095     } while (threadIsSuspended);
2096   }
2097 }
2098 
2099 int os::signal_lookup() {
2100   return check_pending_signals(false);
2101 }
2102 
2103 int os::signal_wait() {
2104   return check_pending_signals(true);
2105 }
2106 
2107 ////////////////////////////////////////////////////////////////////////////////
2108 // Virtual Memory
2109 
2110 int os::vm_page_size() {
2111   // Seems redundant as all get out
2112   assert(os::Bsd::page_size() != -1, "must call os::init");
2113   return os::Bsd::page_size();
2114 }
2115 
2116 // Solaris allocates memory by pages.
2117 int os::vm_allocation_granularity() {
2118   assert(os::Bsd::page_size() != -1, "must call os::init");
2119   return os::Bsd::page_size();
2120 }
2121 
2122 // Rationale behind this function:
2123 //  current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2124 //  mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2125 //  samples for JITted code. Here we create private executable mapping over the code cache
2126 //  and then we can use standard (well, almost, as mapping can change) way to provide
2127 //  info for the reporting script by storing timestamp and location of symbol
2128 void bsd_wrap_code(char* base, size_t size) {
2129   static volatile jint cnt = 0;
2130 
2131   if (!UseOprofile) {
2132     return;
2133   }
2134 
2135   char buf[PATH_MAX + 1];
2136   int num = Atomic::add(1, &cnt);
2137 
2138   snprintf(buf, PATH_MAX + 1, "%s/hs-vm-%d-%d",
2139            os::get_temp_directory(), os::current_process_id(), num);
2140   unlink(buf);
2141 
2142   int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2143 
2144   if (fd != -1) {
2145     off_t rv = ::lseek(fd, size-2, SEEK_SET);
2146     if (rv != (off_t)-1) {
2147       if (::write(fd, "", 1) == 1) {
2148         mmap(base, size,
2149              PROT_READ|PROT_WRITE|PROT_EXEC,
2150              MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2151       }
2152     }
2153     ::close(fd);
2154     unlink(buf);
2155   }
2156 }
2157 
2158 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2159                                     int err) {
2160   warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2161           ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2162           strerror(err), err);
2163 }
2164 
2165 // NOTE: Bsd kernel does not really reserve the pages for us.
2166 //       All it does is to check if there are enough free pages
2167 //       left at the time of mmap(). This could be a potential
2168 //       problem.
2169 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2170   int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2171 #ifdef __OpenBSD__
2172   // XXX: Work-around mmap/MAP_FIXED bug temporarily on OpenBSD
2173   if (::mprotect(addr, size, prot) == 0) {
2174     return true;
2175   }
2176 #else
2177   uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2178                                    MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2179   if (res != (uintptr_t) MAP_FAILED) {
2180     return true;
2181   }
2182 #endif
2183 
2184   // Warn about any commit errors we see in non-product builds just
2185   // in case mmap() doesn't work as described on the man page.
2186   NOT_PRODUCT(warn_fail_commit_memory(addr, size, exec, errno);)
2187 
2188   return false;
2189 }
2190 
2191 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2192                        bool exec) {
2193   // alignment_hint is ignored on this OS
2194   return pd_commit_memory(addr, size, exec);
2195 }
2196 
2197 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2198                                   const char* mesg) {
2199   assert(mesg != NULL, "mesg must be specified");
2200   if (!pd_commit_memory(addr, size, exec)) {
2201     // add extra info in product mode for vm_exit_out_of_memory():
2202     PRODUCT_ONLY(warn_fail_commit_memory(addr, size, exec, errno);)
2203     vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2204   }
2205 }
2206 
2207 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2208                                   size_t alignment_hint, bool exec,
2209                                   const char* mesg) {
2210   // alignment_hint is ignored on this OS
2211   pd_commit_memory_or_exit(addr, size, exec, mesg);
2212 }
2213 
2214 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2215 }
2216 
2217 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2218   ::madvise(addr, bytes, MADV_DONTNEED);
2219 }
2220 
2221 void os::numa_make_global(char *addr, size_t bytes) {
2222 }
2223 
2224 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2225 }
2226 
2227 bool os::numa_topology_changed()   { return false; }
2228 
2229 size_t os::numa_get_groups_num() {
2230   return 1;
2231 }
2232 
2233 int os::numa_get_group_id() {
2234   return 0;
2235 }
2236 
2237 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2238   if (size > 0) {
2239     ids[0] = 0;
2240     return 1;
2241   }
2242   return 0;
2243 }
2244 
2245 bool os::get_page_info(char *start, page_info* info) {
2246   return false;
2247 }
2248 
2249 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2250   return end;
2251 }
2252 
2253 
2254 bool os::pd_uncommit_memory(char* addr, size_t size) {
2255 #ifdef __OpenBSD__
2256   // XXX: Work-around mmap/MAP_FIXED bug temporarily on OpenBSD
2257   return ::mprotect(addr, size, PROT_NONE) == 0;
2258 #else
2259   uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2260                 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2261   return res  != (uintptr_t) MAP_FAILED;
2262 #endif
2263 }
2264 
2265 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2266   return os::commit_memory(addr, size, !ExecMem);
2267 }
2268 
2269 // If this is a growable mapping, remove the guard pages entirely by
2270 // munmap()ping them.  If not, just call uncommit_memory().
2271 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2272   return os::uncommit_memory(addr, size);
2273 }
2274 
2275 static address _highest_vm_reserved_address = NULL;
2276 
2277 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2278 // at 'requested_addr'. If there are existing memory mappings at the same
2279 // location, however, they will be overwritten. If 'fixed' is false,
2280 // 'requested_addr' is only treated as a hint, the return value may or
2281 // may not start from the requested address. Unlike Bsd mmap(), this
2282 // function returns NULL to indicate failure.
2283 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2284   char * addr;
2285   int flags;
2286 
2287   flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2288   if (fixed) {
2289     assert((uintptr_t)requested_addr % os::Bsd::page_size() == 0, "unaligned address");
2290     flags |= MAP_FIXED;
2291   }
2292 
2293   // Map reserved/uncommitted pages PROT_NONE so we fail early if we
2294   // touch an uncommitted page. Otherwise, the read/write might
2295   // succeed if we have enough swap space to back the physical page.
2296   addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
2297                        flags, -1, 0);
2298 
2299   if (addr != MAP_FAILED) {
2300     // anon_mmap() should only get called during VM initialization,
2301     // don't need lock (actually we can skip locking even it can be called
2302     // from multiple threads, because _highest_vm_reserved_address is just a
2303     // hint about the upper limit of non-stack memory regions.)
2304     if ((address)addr + bytes > _highest_vm_reserved_address) {
2305       _highest_vm_reserved_address = (address)addr + bytes;
2306     }
2307   }
2308 
2309   return addr == MAP_FAILED ? NULL : addr;
2310 }
2311 
2312 // Don't update _highest_vm_reserved_address, because there might be memory
2313 // regions above addr + size. If so, releasing a memory region only creates
2314 // a hole in the address space, it doesn't help prevent heap-stack collision.
2315 //
2316 static int anon_munmap(char * addr, size_t size) {
2317   return ::munmap(addr, size) == 0;
2318 }
2319 
2320 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
2321                          size_t alignment_hint) {
2322   return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2323 }
2324 
2325 bool os::pd_release_memory(char* addr, size_t size) {
2326   return anon_munmap(addr, size);
2327 }
2328 
2329 static bool bsd_mprotect(char* addr, size_t size, int prot) {
2330   // Bsd wants the mprotect address argument to be page aligned.
2331   char* bottom = (char*)align_size_down((intptr_t)addr, os::Bsd::page_size());
2332 
2333   // According to SUSv3, mprotect() should only be used with mappings
2334   // established by mmap(), and mmap() always maps whole pages. Unaligned
2335   // 'addr' likely indicates problem in the VM (e.g. trying to change
2336   // protection of malloc'ed or statically allocated memory). Check the
2337   // caller if you hit this assert.
2338   assert(addr == bottom, "sanity check");
2339 
2340   size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Bsd::page_size());
2341   return ::mprotect(bottom, size, prot) == 0;
2342 }
2343 
2344 // Set protections specified
2345 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2346                         bool is_committed) {
2347   unsigned int p = 0;
2348   switch (prot) {
2349   case MEM_PROT_NONE: p = PROT_NONE; break;
2350   case MEM_PROT_READ: p = PROT_READ; break;
2351   case MEM_PROT_RW:   p = PROT_READ|PROT_WRITE; break;
2352   case MEM_PROT_RWX:  p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2353   default:
2354     ShouldNotReachHere();
2355   }
2356   // is_committed is unused.
2357   return bsd_mprotect(addr, bytes, p);
2358 }
2359 
2360 bool os::guard_memory(char* addr, size_t size) {
2361   return bsd_mprotect(addr, size, PROT_NONE);
2362 }
2363 
2364 bool os::unguard_memory(char* addr, size_t size) {
2365   return bsd_mprotect(addr, size, PROT_READ|PROT_WRITE);
2366 }
2367 
2368 bool os::Bsd::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2369   return false;
2370 }
2371 
2372 // Large page support
2373 
2374 static size_t _large_page_size = 0;
2375 
2376 void os::large_page_init() {
2377 }
2378 
2379 
2380 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
2381   fatal("This code is not used or maintained.");
2382 
2383   // "exec" is passed in but not used.  Creating the shared image for
2384   // the code cache doesn't have an SHM_X executable permission to check.
2385   assert(UseLargePages && UseSHM, "only for SHM large pages");
2386 
2387   key_t key = IPC_PRIVATE;
2388   char *addr;
2389 
2390   bool warn_on_failure = UseLargePages &&
2391                         (!FLAG_IS_DEFAULT(UseLargePages) ||
2392                          !FLAG_IS_DEFAULT(LargePageSizeInBytes)
2393                         );
2394 
2395   // Create a large shared memory region to attach to based on size.
2396   // Currently, size is the total size of the heap
2397   int shmid = shmget(key, bytes, IPC_CREAT|SHM_R|SHM_W);
2398   if (shmid == -1) {
2399      // Possible reasons for shmget failure:
2400      // 1. shmmax is too small for Java heap.
2401      //    > check shmmax value: cat /proc/sys/kernel/shmmax
2402      //    > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
2403      // 2. not enough large page memory.
2404      //    > check available large pages: cat /proc/meminfo
2405      //    > increase amount of large pages:
2406      //          echo new_value > /proc/sys/vm/nr_hugepages
2407      //      Note 1: different Bsd may use different name for this property,
2408      //            e.g. on Redhat AS-3 it is "hugetlb_pool".
2409      //      Note 2: it's possible there's enough physical memory available but
2410      //            they are so fragmented after a long run that they can't
2411      //            coalesce into large pages. Try to reserve large pages when
2412      //            the system is still "fresh".
2413      if (warn_on_failure) {
2414        warning("Failed to reserve shared memory (errno = %d).", errno);
2415      }
2416      return NULL;
2417   }
2418 
2419   // attach to the region
2420   addr = (char*)shmat(shmid, req_addr, 0);
2421   int err = errno;
2422 
2423   // Remove shmid. If shmat() is successful, the actual shared memory segment
2424   // will be deleted when it's detached by shmdt() or when the process
2425   // terminates. If shmat() is not successful this will remove the shared
2426   // segment immediately.
2427   shmctl(shmid, IPC_RMID, NULL);
2428 
2429   if ((intptr_t)addr == -1) {
2430      if (warn_on_failure) {
2431        warning("Failed to attach shared memory (errno = %d).", err);
2432      }
2433      return NULL;
2434   }
2435 
2436   // The memory is committed
2437   MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
2438 
2439   return addr;
2440 }
2441 
2442 bool os::release_memory_special(char* base, size_t bytes) {
2443   if (MemTracker::tracking_level() > NMT_minimal) {
2444     Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
2445     // detaching the SHM segment will also delete it, see reserve_memory_special()
2446     int rslt = shmdt(base);
2447     if (rslt == 0) {
2448       tkr.record((address)base, bytes);
2449       return true;
2450     } else {
2451       return false;
2452     }
2453   } else {
2454     return shmdt(base) == 0;
2455   }
2456 }
2457 
2458 size_t os::large_page_size() {
2459   return _large_page_size;
2460 }
2461 
2462 // HugeTLBFS allows application to commit large page memory on demand;
2463 // with SysV SHM the entire memory region must be allocated as shared
2464 // memory.
2465 bool os::can_commit_large_page_memory() {
2466   return UseHugeTLBFS;
2467 }
2468 
2469 bool os::can_execute_large_page_memory() {
2470   return UseHugeTLBFS;
2471 }
2472 
2473 // Reserve memory at an arbitrary address, only if that area is
2474 // available (and not reserved for something else).
2475 
2476 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
2477   const int max_tries = 10;
2478   char* base[max_tries];
2479   size_t size[max_tries];
2480   const size_t gap = 0x000000;
2481 
2482   // Assert only that the size is a multiple of the page size, since
2483   // that's all that mmap requires, and since that's all we really know
2484   // about at this low abstraction level.  If we need higher alignment,
2485   // we can either pass an alignment to this method or verify alignment
2486   // in one of the methods further up the call chain.  See bug 5044738.
2487   assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
2488 
2489   // Repeatedly allocate blocks until the block is allocated at the
2490   // right spot. Give up after max_tries. Note that reserve_memory() will
2491   // automatically update _highest_vm_reserved_address if the call is
2492   // successful. The variable tracks the highest memory address every reserved
2493   // by JVM. It is used to detect heap-stack collision if running with
2494   // fixed-stack BsdThreads. Because here we may attempt to reserve more
2495   // space than needed, it could confuse the collision detecting code. To
2496   // solve the problem, save current _highest_vm_reserved_address and
2497   // calculate the correct value before return.
2498   address old_highest = _highest_vm_reserved_address;
2499 
2500   // Bsd mmap allows caller to pass an address as hint; give it a try first,
2501   // if kernel honors the hint then we can return immediately.
2502   char * addr = anon_mmap(requested_addr, bytes, false);
2503   if (addr == requested_addr) {
2504      return requested_addr;
2505   }
2506 
2507   if (addr != NULL) {
2508      // mmap() is successful but it fails to reserve at the requested address
2509      anon_munmap(addr, bytes);
2510   }
2511 
2512   int i;
2513   for (i = 0; i < max_tries; ++i) {
2514     base[i] = reserve_memory(bytes);
2515 
2516     if (base[i] != NULL) {
2517       // Is this the block we wanted?
2518       if (base[i] == requested_addr) {
2519         size[i] = bytes;
2520         break;
2521       }
2522 
2523       // Does this overlap the block we wanted? Give back the overlapped
2524       // parts and try again.
2525 
2526       size_t top_overlap = requested_addr + (bytes + gap) - base[i];
2527       if (top_overlap >= 0 && top_overlap < bytes) {
2528         unmap_memory(base[i], top_overlap);
2529         base[i] += top_overlap;
2530         size[i] = bytes - top_overlap;
2531       } else {
2532         size_t bottom_overlap = base[i] + bytes - requested_addr;
2533         if (bottom_overlap >= 0 && bottom_overlap < bytes) {
2534           unmap_memory(requested_addr, bottom_overlap);
2535           size[i] = bytes - bottom_overlap;
2536         } else {
2537           size[i] = bytes;
2538         }
2539       }
2540     }
2541   }
2542 
2543   // Give back the unused reserved pieces.
2544 
2545   for (int j = 0; j < i; ++j) {
2546     if (base[j] != NULL) {
2547       unmap_memory(base[j], size[j]);
2548     }
2549   }
2550 
2551   if (i < max_tries) {
2552     _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
2553     return requested_addr;
2554   } else {
2555     _highest_vm_reserved_address = old_highest;
2556     return NULL;
2557   }
2558 }
2559 
2560 size_t os::read(int fd, void *buf, unsigned int nBytes) {
2561   RESTARTABLE_RETURN_INT(::read(fd, buf, nBytes));
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   }
2572   else {
2573     req.tv_nsec = 1;
2574   }
2575 
2576   nanosleep(&req, NULL);
2577 
2578   return;
2579 }
2580 
2581 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
2582 void os::infinite_sleep() {
2583   while (true) {    // sleep forever ...
2584     ::sleep(100);   // ... 100 seconds at a time
2585   }
2586 }
2587 
2588 // Used to convert frequent JVM_Yield() to nops
2589 bool os::dont_yield() {
2590   return DontYieldALot;
2591 }
2592 
2593 void os::naked_yield() {
2594   sched_yield();
2595 }
2596 
2597 ////////////////////////////////////////////////////////////////////////////////
2598 // thread priority support
2599 
2600 // Note: Normal Bsd applications are run with SCHED_OTHER policy. SCHED_OTHER
2601 // only supports dynamic priority, static priority must be zero. For real-time
2602 // applications, Bsd supports SCHED_RR which allows static priority (1-99).
2603 // However, for large multi-threaded applications, SCHED_RR is not only slower
2604 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
2605 // of 5 runs - Sep 2005).
2606 //
2607 // The following code actually changes the niceness of kernel-thread/LWP. It
2608 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
2609 // not the entire user process, and user level threads are 1:1 mapped to kernel
2610 // threads. It has always been the case, but could change in the future. For
2611 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
2612 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
2613 
2614 #if !defined(__APPLE__)
2615 int os::java_to_os_priority[CriticalPriority + 1] = {
2616   19,              // 0 Entry should never be used
2617 
2618    0,              // 1 MinPriority
2619    3,              // 2
2620    6,              // 3
2621 
2622   10,              // 4
2623   15,              // 5 NormPriority
2624   18,              // 6
2625 
2626   21,              // 7
2627   25,              // 8
2628   28,              // 9 NearMaxPriority
2629 
2630   31,              // 10 MaxPriority
2631 
2632   31               // 11 CriticalPriority
2633 };
2634 #else
2635 /* Using Mach high-level priority assignments */
2636 int os::java_to_os_priority[CriticalPriority + 1] = {
2637    0,              // 0 Entry should never be used (MINPRI_USER)
2638 
2639   27,              // 1 MinPriority
2640   28,              // 2
2641   29,              // 3
2642 
2643   30,              // 4
2644   31,              // 5 NormPriority (BASEPRI_DEFAULT)
2645   32,              // 6
2646 
2647   33,              // 7
2648   34,              // 8
2649   35,              // 9 NearMaxPriority
2650 
2651   36,              // 10 MaxPriority
2652 
2653   36               // 11 CriticalPriority
2654 };
2655 #endif
2656 
2657 static int prio_init() {
2658   if (ThreadPriorityPolicy == 1) {
2659     // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
2660     // if effective uid is not root. Perhaps, a more elegant way of doing
2661     // this is to test CAP_SYS_NICE capability, but that will require libcap.so
2662     if (geteuid() != 0) {
2663       if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
2664         warning("-XX:ThreadPriorityPolicy requires root privilege on Bsd");
2665       }
2666       ThreadPriorityPolicy = 0;
2667     }
2668   }
2669   if (UseCriticalJavaThreadPriority) {
2670     os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
2671   }
2672   return 0;
2673 }
2674 
2675 OSReturn os::set_native_priority(Thread* thread, int newpri) {
2676   if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
2677 
2678 #ifdef __OpenBSD__
2679   // OpenBSD pthread_setprio starves low priority threads
2680   return OS_OK;
2681 #elif defined(__FreeBSD__)
2682   int ret = pthread_setprio(thread->osthread()->pthread_id(), newpri);
2683 #elif defined(__APPLE__) || defined(__NetBSD__)
2684   struct sched_param sp;
2685   int policy;
2686   pthread_t self = pthread_self();
2687 
2688   if (pthread_getschedparam(self, &policy, &sp) != 0)
2689     return OS_ERR;
2690 
2691   sp.sched_priority = newpri;
2692   if (pthread_setschedparam(self, policy, &sp) != 0)
2693     return OS_ERR;
2694 
2695   return OS_OK;
2696 #else
2697   int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
2698   return (ret == 0) ? OS_OK : OS_ERR;
2699 #endif
2700 }
2701 
2702 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
2703   if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
2704     *priority_ptr = java_to_os_priority[NormPriority];
2705     return OS_OK;
2706   }
2707 
2708   errno = 0;
2709 #if defined(__OpenBSD__) || defined(__FreeBSD__)
2710   *priority_ptr = pthread_getprio(thread->osthread()->pthread_id());
2711 #elif defined(__APPLE__) || defined(__NetBSD__)
2712   int policy;
2713   struct sched_param sp;
2714 
2715   pthread_getschedparam(pthread_self(), &policy, &sp);
2716   *priority_ptr = sp.sched_priority;
2717 #else
2718   *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
2719 #endif
2720   return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
2721 }
2722 
2723 // Hint to the underlying OS that a task switch would not be good.
2724 // Void return because it's a hint and can fail.
2725 void os::hint_no_preempt() {}
2726 
2727 ////////////////////////////////////////////////////////////////////////////////
2728 // suspend/resume support
2729 
2730 //  the low-level signal-based suspend/resume support is a remnant from the
2731 //  old VM-suspension that used to be for java-suspension, safepoints etc,
2732 //  within hotspot. Now there is a single use-case for this:
2733 //    - calling get_thread_pc() on the VMThread by the flat-profiler task
2734 //      that runs in the watcher thread.
2735 //  The remaining code is greatly simplified from the more general suspension
2736 //  code that used to be used.
2737 //
2738 //  The protocol is quite simple:
2739 //  - suspend:
2740 //      - sends a signal to the target thread
2741 //      - polls the suspend state of the osthread using a yield loop
2742 //      - target thread signal handler (SR_handler) sets suspend state
2743 //        and blocks in sigsuspend until continued
2744 //  - resume:
2745 //      - sets target osthread state to continue
2746 //      - sends signal to end the sigsuspend loop in the SR_handler
2747 //
2748 //  Note that the SR_lock plays no role in this suspend/resume protocol.
2749 //
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 //
2762 // Handler function invoked when a thread's execution is suspended or
2763 // resumed. We have to be careful that only async-safe functions are
2764 // called here (Note: most pthread functions are not async safe and
2765 // should be avoided.)
2766 //
2767 // Note: sigwait() is a more natural fit than sigsuspend() from an
2768 // interface point of view, but sigwait() prevents the signal hander
2769 // from being run. libpthread would get very confused by not having
2770 // its signal handlers run and prevents sigwait()'s use with the
2771 // mutex granting granting signal.
2772 //
2773 // Currently only ever called on the VMThread or JavaThread
2774 //
2775 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
2776   // Save and restore errno to avoid confusing native code with EINTR
2777   // after sigsuspend.
2778   int old_errno = errno;
2779 
2780   Thread* thread = Thread::current();
2781   OSThread* osthread = thread->osthread();
2782   assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
2783 
2784   os::SuspendResume::State current = osthread->sr.state();
2785   if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
2786     suspend_save_context(osthread, siginfo, context);
2787 
2788     // attempt to switch the state, we assume we had a SUSPEND_REQUEST
2789     os::SuspendResume::State state = osthread->sr.suspended();
2790     if (state == os::SuspendResume::SR_SUSPENDED) {
2791       sigset_t suspend_set;  // signals for sigsuspend()
2792 
2793       // get current set of blocked signals and unblock resume signal
2794       pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
2795       sigdelset(&suspend_set, SR_signum);
2796 
2797       sr_semaphore.signal();
2798       // wait here until we are resumed
2799       while (1) {
2800         sigsuspend(&suspend_set);
2801 
2802         os::SuspendResume::State result = osthread->sr.running();
2803         if (result == os::SuspendResume::SR_RUNNING) {
2804           sr_semaphore.signal();
2805           break;
2806         } else if (result != os::SuspendResume::SR_SUSPENDED) {
2807           ShouldNotReachHere();
2808         }
2809       }
2810 
2811     } else if (state == os::SuspendResume::SR_RUNNING) {
2812       // request was cancelled, continue
2813     } else {
2814       ShouldNotReachHere();
2815     }
2816 
2817     resume_clear_context(osthread);
2818   } else if (current == os::SuspendResume::SR_RUNNING) {
2819     // request was cancelled, continue
2820   } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
2821     // ignore
2822   } else {
2823     // ignore
2824   }
2825 
2826   errno = old_errno;
2827 }
2828 
2829 
2830 static int SR_initialize() {
2831   struct sigaction act;
2832   char *s;
2833   /* Get signal number to use for suspend/resume */
2834   if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
2835     int sig = ::strtol(s, 0, 10);
2836     if (sig > 0 || sig < NSIG) {
2837         SR_signum = sig;
2838     }
2839   }
2840 
2841   assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
2842         "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
2843 
2844   sigemptyset(&SR_sigset);
2845   sigaddset(&SR_sigset, SR_signum);
2846 
2847   /* Set up signal handler for suspend/resume */
2848   act.sa_flags = SA_RESTART|SA_SIGINFO;
2849   act.sa_handler = (void (*)(int)) SR_handler;
2850 
2851   // SR_signum is blocked by default.
2852   // 4528190 - We also need to block pthread restart signal (32 on all
2853   // supported Bsd platforms). Note that BsdThreads need to block
2854   // this signal for all threads to work properly. So we don't have
2855   // to use hard-coded signal number when setting up the mask.
2856   pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
2857 
2858   if (sigaction(SR_signum, &act, 0) == -1) {
2859     return -1;
2860   }
2861 
2862   // Save signal flag
2863   os::Bsd::set_our_sigflags(SR_signum, act.sa_flags);
2864   return 0;
2865 }
2866 
2867 static int sr_notify(OSThread* osthread) {
2868   int status = pthread_kill(osthread->pthread_id(), SR_signum);
2869   assert_status(status == 0, status, "pthread_kill");
2870   return status;
2871 }
2872 
2873 // "Randomly" selected value for how long we want to spin
2874 // before bailing out on suspending a thread, also how often
2875 // we send a signal to a thread we want to resume
2876 static const int RANDOMLY_LARGE_INTEGER = 1000000;
2877 static const int RANDOMLY_LARGE_INTEGER2 = 100;
2878 
2879 // returns true on success and false on error - really an error is fatal
2880 // but this seems the normal response to library errors
2881 static bool do_suspend(OSThread* osthread) {
2882   assert(osthread->sr.is_running(), "thread should be running");
2883   assert(!sr_semaphore.trywait(), "semaphore has invalid state");
2884 
2885   // mark as suspended and send signal
2886   if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
2887     // failed to switch, state wasn't running?
2888     ShouldNotReachHere();
2889     return false;
2890   }
2891 
2892   if (sr_notify(osthread) != 0) {
2893     ShouldNotReachHere();
2894   }
2895 
2896   // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
2897   while (true) {
2898     if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
2899       break;
2900     } else {
2901       // timeout
2902       os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
2903       if (cancelled == os::SuspendResume::SR_RUNNING) {
2904         return false;
2905       } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
2906         // make sure that we consume the signal on the semaphore as well
2907         sr_semaphore.wait();
2908         break;
2909       } else {
2910         ShouldNotReachHere();
2911         return false;
2912       }
2913     }
2914   }
2915 
2916   guarantee(osthread->sr.is_suspended(), "Must be suspended");
2917   return true;
2918 }
2919 
2920 static void do_resume(OSThread* osthread) {
2921   assert(osthread->sr.is_suspended(), "thread should be suspended");
2922   assert(!sr_semaphore.trywait(), "invalid semaphore state");
2923 
2924   if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
2925     // failed to switch to WAKEUP_REQUEST
2926     ShouldNotReachHere();
2927     return;
2928   }
2929 
2930   while (true) {
2931     if (sr_notify(osthread) == 0) {
2932       if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
2933         if (osthread->sr.is_running()) {
2934           return;
2935         }
2936       }
2937     } else {
2938       ShouldNotReachHere();
2939     }
2940   }
2941 
2942   guarantee(osthread->sr.is_running(), "Must be running!");
2943 }
2944 
2945 ///////////////////////////////////////////////////////////////////////////////////
2946 // signal handling (except suspend/resume)
2947 
2948 // This routine may be used by user applications as a "hook" to catch signals.
2949 // The user-defined signal handler must pass unrecognized signals to this
2950 // routine, and if it returns true (non-zero), then the signal handler must
2951 // return immediately.  If the flag "abort_if_unrecognized" is true, then this
2952 // routine will never retun false (zero), but instead will execute a VM panic
2953 // routine kill the process.
2954 //
2955 // If this routine returns false, it is OK to call it again.  This allows
2956 // the user-defined signal handler to perform checks either before or after
2957 // the VM performs its own checks.  Naturally, the user code would be making
2958 // a serious error if it tried to handle an exception (such as a null check
2959 // or breakpoint) that the VM was generating for its own correct operation.
2960 //
2961 // This routine may recognize any of the following kinds of signals:
2962 //    SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
2963 // It should be consulted by handlers for any of those signals.
2964 //
2965 // The caller of this routine must pass in the three arguments supplied
2966 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
2967 // field of the structure passed to sigaction().  This routine assumes that
2968 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
2969 //
2970 // Note that the VM will print warnings if it detects conflicting signal
2971 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
2972 //
2973 extern "C" JNIEXPORT int
2974 JVM_handle_bsd_signal(int signo, siginfo_t* siginfo,
2975                         void* ucontext, int abort_if_unrecognized);
2976 
2977 void signalHandler(int sig, siginfo_t* info, void* uc) {
2978   assert(info != NULL && uc != NULL, "it must be old kernel");
2979   int orig_errno = errno;  // Preserve errno value over signal handler.
2980   JVM_handle_bsd_signal(sig, info, uc, true);
2981   errno = orig_errno;
2982 }
2983 
2984 
2985 // This boolean allows users to forward their own non-matching signals
2986 // to JVM_handle_bsd_signal, harmlessly.
2987 bool os::Bsd::signal_handlers_are_installed = false;
2988 
2989 // For signal-chaining
2990 struct sigaction os::Bsd::sigact[MAXSIGNUM];
2991 unsigned int os::Bsd::sigs = 0;
2992 bool os::Bsd::libjsig_is_loaded = false;
2993 typedef struct sigaction *(*get_signal_t)(int);
2994 get_signal_t os::Bsd::get_signal_action = NULL;
2995 
2996 struct sigaction* os::Bsd::get_chained_signal_action(int sig) {
2997   struct sigaction *actp = NULL;
2998 
2999   if (libjsig_is_loaded) {
3000     // Retrieve the old signal handler from libjsig
3001     actp = (*get_signal_action)(sig);
3002   }
3003   if (actp == NULL) {
3004     // Retrieve the preinstalled signal handler from jvm
3005     actp = get_preinstalled_handler(sig);
3006   }
3007 
3008   return actp;
3009 }
3010 
3011 static bool call_chained_handler(struct sigaction *actp, int sig,
3012                                  siginfo_t *siginfo, void *context) {
3013   // Call the old signal handler
3014   if (actp->sa_handler == SIG_DFL) {
3015     // It's more reasonable to let jvm treat it as an unexpected exception
3016     // instead of taking the default action.
3017     return false;
3018   } else if (actp->sa_handler != SIG_IGN) {
3019     if ((actp->sa_flags & SA_NODEFER) == 0) {
3020       // automaticlly block the signal
3021       sigaddset(&(actp->sa_mask), sig);
3022     }
3023 
3024     sa_handler_t hand;
3025     sa_sigaction_t sa;
3026     bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3027     // retrieve the chained handler
3028     if (siginfo_flag_set) {
3029       sa = actp->sa_sigaction;
3030     } else {
3031       hand = actp->sa_handler;
3032     }
3033 
3034     if ((actp->sa_flags & SA_RESETHAND) != 0) {
3035       actp->sa_handler = SIG_DFL;
3036     }
3037 
3038     // try to honor the signal mask
3039     sigset_t oset;
3040     pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3041 
3042     // call into the chained handler
3043     if (siginfo_flag_set) {
3044       (*sa)(sig, siginfo, context);
3045     } else {
3046       (*hand)(sig);
3047     }
3048 
3049     // restore the signal mask
3050     pthread_sigmask(SIG_SETMASK, &oset, 0);
3051   }
3052   // Tell jvm's signal handler the signal is taken care of.
3053   return true;
3054 }
3055 
3056 bool os::Bsd::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3057   bool chained = false;
3058   // signal-chaining
3059   if (UseSignalChaining) {
3060     struct sigaction *actp = get_chained_signal_action(sig);
3061     if (actp != NULL) {
3062       chained = call_chained_handler(actp, sig, siginfo, context);
3063     }
3064   }
3065   return chained;
3066 }
3067 
3068 struct sigaction* os::Bsd::get_preinstalled_handler(int sig) {
3069   if ((((unsigned int)1 << sig) & sigs) != 0) {
3070     return &sigact[sig];
3071   }
3072   return NULL;
3073 }
3074 
3075 void os::Bsd::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3076   assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3077   sigact[sig] = oldAct;
3078   sigs |= (unsigned int)1 << sig;
3079 }
3080 
3081 // for diagnostic
3082 int os::Bsd::sigflags[MAXSIGNUM];
3083 
3084 int os::Bsd::get_our_sigflags(int sig) {
3085   assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3086   return sigflags[sig];
3087 }
3088 
3089 void os::Bsd::set_our_sigflags(int sig, int flags) {
3090   assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3091   sigflags[sig] = flags;
3092 }
3093 
3094 void os::Bsd::set_signal_handler(int sig, bool set_installed) {
3095   // Check for overwrite.
3096   struct sigaction oldAct;
3097   sigaction(sig, (struct sigaction*)NULL, &oldAct);
3098 
3099   void* oldhand = oldAct.sa_sigaction
3100                 ? CAST_FROM_FN_PTR(void*,  oldAct.sa_sigaction)
3101                 : CAST_FROM_FN_PTR(void*,  oldAct.sa_handler);
3102   if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3103       oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3104       oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3105     if (AllowUserSignalHandlers || !set_installed) {
3106       // Do not overwrite; user takes responsibility to forward to us.
3107       return;
3108     } else if (UseSignalChaining) {
3109       // save the old handler in jvm
3110       save_preinstalled_handler(sig, oldAct);
3111       // libjsig also interposes the sigaction() call below and saves the
3112       // old sigaction on it own.
3113     } else {
3114       fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
3115                     "%#lx for signal %d.", (long)oldhand, sig));
3116     }
3117   }
3118 
3119   struct sigaction sigAct;
3120   sigfillset(&(sigAct.sa_mask));
3121   sigAct.sa_handler = SIG_DFL;
3122   if (!set_installed) {
3123     sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3124   } else {
3125     sigAct.sa_sigaction = signalHandler;
3126     sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3127   }
3128 #ifdef __APPLE__
3129   // Needed for main thread as XNU (Mac OS X kernel) will only deliver SIGSEGV
3130   // (which starts as SIGBUS) on main thread with faulting address inside "stack+guard pages"
3131   // if the signal handler declares it will handle it on alternate stack.
3132   // Notice we only declare we will handle it on alt stack, but we are not
3133   // actually going to use real alt stack - this is just a workaround.
3134   // Please see ux_exception.c, method catch_mach_exception_raise for details
3135   // link http://www.opensource.apple.com/source/xnu/xnu-2050.18.24/bsd/uxkern/ux_exception.c
3136   if (sig == SIGSEGV) {
3137     sigAct.sa_flags |= SA_ONSTACK;
3138   }
3139 #endif
3140 
3141   // Save flags, which are set by ours
3142   assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3143   sigflags[sig] = sigAct.sa_flags;
3144 
3145   int ret = sigaction(sig, &sigAct, &oldAct);
3146   assert(ret == 0, "check");
3147 
3148   void* oldhand2  = oldAct.sa_sigaction
3149                   ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3150                   : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3151   assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3152 }
3153 
3154 // install signal handlers for signals that HotSpot needs to
3155 // handle in order to support Java-level exception handling.
3156 
3157 void os::Bsd::install_signal_handlers() {
3158   if (!signal_handlers_are_installed) {
3159     signal_handlers_are_installed = true;
3160 
3161     // signal-chaining
3162     typedef void (*signal_setting_t)();
3163     signal_setting_t begin_signal_setting = NULL;
3164     signal_setting_t end_signal_setting = NULL;
3165     begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3166                              dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3167     if (begin_signal_setting != NULL) {
3168       end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3169                              dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3170       get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3171                             dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3172       libjsig_is_loaded = true;
3173       assert(UseSignalChaining, "should enable signal-chaining");
3174     }
3175     if (libjsig_is_loaded) {
3176       // Tell libjsig jvm is setting signal handlers
3177       (*begin_signal_setting)();
3178     }
3179 
3180     set_signal_handler(SIGSEGV, true);
3181     set_signal_handler(SIGPIPE, true);
3182     set_signal_handler(SIGBUS, true);
3183     set_signal_handler(SIGILL, true);
3184     set_signal_handler(SIGFPE, true);
3185     set_signal_handler(SIGXFSZ, true);
3186 
3187 #if defined(__APPLE__)
3188     // In Mac OS X 10.4, CrashReporter will write a crash log for all 'fatal' signals, including
3189     // signals caught and handled by the JVM. To work around this, we reset the mach task
3190     // signal handler that's placed on our process by CrashReporter. This disables
3191     // CrashReporter-based reporting.
3192     //
3193     // This work-around is not necessary for 10.5+, as CrashReporter no longer intercedes
3194     // on caught fatal signals.
3195     //
3196     // Additionally, gdb installs both standard BSD signal handlers, and mach exception
3197     // handlers. By replacing the existing task exception handler, we disable gdb's mach
3198     // exception handling, while leaving the standard BSD signal handlers functional.
3199     kern_return_t kr;
3200     kr = task_set_exception_ports(mach_task_self(),
3201         EXC_MASK_BAD_ACCESS | EXC_MASK_ARITHMETIC,
3202         MACH_PORT_NULL,
3203         EXCEPTION_STATE_IDENTITY,
3204         MACHINE_THREAD_STATE);
3205 
3206     assert(kr == KERN_SUCCESS, "could not set mach task signal handler");
3207 #endif
3208 
3209     if (libjsig_is_loaded) {
3210       // Tell libjsig jvm finishes setting signal handlers
3211       (*end_signal_setting)();
3212     }
3213 
3214     // We don't activate signal checker if libjsig is in place, we trust ourselves
3215     // and if UserSignalHandler is installed all bets are off
3216     if (CheckJNICalls) {
3217       if (libjsig_is_loaded) {
3218         if (PrintJNIResolving) {
3219           tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3220         }
3221         check_signals = false;
3222       }
3223       if (AllowUserSignalHandlers) {
3224         if (PrintJNIResolving) {
3225           tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3226         }
3227         check_signals = false;
3228       }
3229     }
3230   }
3231 }
3232 
3233 
3234 /////
3235 // glibc on Bsd platform uses non-documented flag
3236 // to indicate, that some special sort of signal
3237 // trampoline is used.
3238 // We will never set this flag, and we should
3239 // ignore this flag in our diagnostic
3240 #ifdef SIGNIFICANT_SIGNAL_MASK
3241 #undef SIGNIFICANT_SIGNAL_MASK
3242 #endif
3243 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3244 
3245 static const char* get_signal_handler_name(address handler,
3246                                            char* buf, int buflen) {
3247   int offset;
3248   bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3249   if (found) {
3250     // skip directory names
3251     const char *p1, *p2;
3252     p1 = buf;
3253     size_t len = strlen(os::file_separator());
3254     while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3255     jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3256   } else {
3257     jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3258   }
3259   return buf;
3260 }
3261 
3262 static void print_signal_handler(outputStream* st, int sig,
3263                                  char* buf, size_t buflen) {
3264   struct sigaction sa;
3265 
3266   sigaction(sig, NULL, &sa);
3267 
3268   // See comment for SIGNIFICANT_SIGNAL_MASK define
3269   sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3270 
3271   st->print("%s: ", os::exception_name(sig, buf, buflen));
3272 
3273   address handler = (sa.sa_flags & SA_SIGINFO)
3274     ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3275     : CAST_FROM_FN_PTR(address, sa.sa_handler);
3276 
3277   if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3278     st->print("SIG_DFL");
3279   } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3280     st->print("SIG_IGN");
3281   } else {
3282     st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3283   }
3284 
3285   st->print(", sa_mask[0]=");
3286   os::Posix::print_signal_set_short(st, &sa.sa_mask);
3287 
3288   address rh = VMError::get_resetted_sighandler(sig);
3289   // May be, handler was resetted by VMError?
3290   if (rh != NULL) {
3291     handler = rh;
3292     sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3293   }
3294 
3295   st->print(", sa_flags=");
3296   os::Posix::print_sa_flags(st, sa.sa_flags);
3297 
3298   // Check: is it our handler?
3299   if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3300      handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3301     // It is our signal handler
3302     // check for flags, reset system-used one!
3303     if ((int)sa.sa_flags != os::Bsd::get_our_sigflags(sig)) {
3304       st->print(
3305                 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3306                 os::Bsd::get_our_sigflags(sig));
3307     }
3308   }
3309   st->cr();
3310 }
3311 
3312 
3313 #define DO_SIGNAL_CHECK(sig) \
3314   if (!sigismember(&check_signal_done, sig)) \
3315     os::Bsd::check_signal_handler(sig)
3316 
3317 // This method is a periodic task to check for misbehaving JNI applications
3318 // under CheckJNI, we can add any periodic checks here
3319 
3320 void os::run_periodic_checks() {
3321 
3322   if (check_signals == false) return;
3323 
3324   // SEGV and BUS if overridden could potentially prevent
3325   // generation of hs*.log in the event of a crash, debugging
3326   // such a case can be very challenging, so we absolutely
3327   // check the following for a good measure:
3328   DO_SIGNAL_CHECK(SIGSEGV);
3329   DO_SIGNAL_CHECK(SIGILL);
3330   DO_SIGNAL_CHECK(SIGFPE);
3331   DO_SIGNAL_CHECK(SIGBUS);
3332   DO_SIGNAL_CHECK(SIGPIPE);
3333   DO_SIGNAL_CHECK(SIGXFSZ);
3334 
3335 
3336   // ReduceSignalUsage allows the user to override these handlers
3337   // see comments at the very top and jvm_solaris.h
3338   if (!ReduceSignalUsage) {
3339     DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
3340     DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
3341     DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
3342     DO_SIGNAL_CHECK(BREAK_SIGNAL);
3343   }
3344 
3345   DO_SIGNAL_CHECK(SR_signum);
3346   DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
3347 }
3348 
3349 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
3350 
3351 static os_sigaction_t os_sigaction = NULL;
3352 
3353 void os::Bsd::check_signal_handler(int sig) {
3354   char buf[O_BUFLEN];
3355   address jvmHandler = NULL;
3356 
3357 
3358   struct sigaction act;
3359   if (os_sigaction == NULL) {
3360     // only trust the default sigaction, in case it has been interposed
3361     os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
3362     if (os_sigaction == NULL) return;
3363   }
3364 
3365   os_sigaction(sig, (struct sigaction*)NULL, &act);
3366 
3367 
3368   act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3369 
3370   address thisHandler = (act.sa_flags & SA_SIGINFO)
3371     ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
3372     : CAST_FROM_FN_PTR(address, act.sa_handler);
3373 
3374 
3375   switch (sig) {
3376   case SIGSEGV:
3377   case SIGBUS:
3378   case SIGFPE:
3379   case SIGPIPE:
3380   case SIGILL:
3381   case SIGXFSZ:
3382     jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
3383     break;
3384 
3385   case SHUTDOWN1_SIGNAL:
3386   case SHUTDOWN2_SIGNAL:
3387   case SHUTDOWN3_SIGNAL:
3388   case BREAK_SIGNAL:
3389     jvmHandler = (address)user_handler();
3390     break;
3391 
3392   case INTERRUPT_SIGNAL:
3393     jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
3394     break;
3395 
3396   default:
3397     if (sig == SR_signum) {
3398       jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
3399     } else {
3400       return;
3401     }
3402     break;
3403   }
3404 
3405   if (thisHandler != jvmHandler) {
3406     tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
3407     tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
3408     tty->print_cr("  found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
3409     // No need to check this sig any longer
3410     sigaddset(&check_signal_done, sig);
3411     // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
3412     if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
3413       tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
3414                     exception_name(sig, buf, O_BUFLEN));
3415     }
3416   } else if(os::Bsd::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Bsd::get_our_sigflags(sig)) {
3417     tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
3418     tty->print("expected:" PTR32_FORMAT, os::Bsd::get_our_sigflags(sig));
3419     tty->print_cr("  found:" PTR32_FORMAT, act.sa_flags);
3420     // No need to check this sig any longer
3421     sigaddset(&check_signal_done, sig);
3422   }
3423 
3424   // Dump all the signal
3425   if (sigismember(&check_signal_done, sig)) {
3426     print_signal_handlers(tty, buf, O_BUFLEN);
3427   }
3428 }
3429 
3430 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
3431 
3432 extern bool signal_name(int signo, char* buf, size_t len);
3433 
3434 const char* os::exception_name(int exception_code, char* buf, size_t size) {
3435   if (0 < exception_code && exception_code <= SIGRTMAX) {
3436     // signal
3437     if (!signal_name(exception_code, buf, size)) {
3438       jio_snprintf(buf, size, "SIG%d", exception_code);
3439     }
3440     return buf;
3441   } else {
3442     return NULL;
3443   }
3444 }
3445 
3446 // this is called _before_ the most of global arguments have been parsed
3447 void os::init(void) {
3448   char dummy;   /* used to get a guess on initial stack address */
3449 //  first_hrtime = gethrtime();
3450 
3451   // With BsdThreads the JavaMain thread pid (primordial thread)
3452   // is different than the pid of the java launcher thread.
3453   // So, on Bsd, the launcher thread pid is passed to the VM
3454   // via the sun.java.launcher.pid property.
3455   // Use this property instead of getpid() if it was correctly passed.
3456   // See bug 6351349.
3457   pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
3458 
3459   _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
3460 
3461   clock_tics_per_sec = CLK_TCK;
3462 
3463   init_random(1234567);
3464 
3465   ThreadCritical::initialize();
3466 
3467   Bsd::set_page_size(getpagesize());
3468   if (Bsd::page_size() == -1) {
3469     fatal(err_msg("os_bsd.cpp: os::init: sysconf failed (%s)",
3470                   strerror(errno)));
3471   }
3472   init_page_sizes((size_t) Bsd::page_size());
3473 
3474   Bsd::initialize_system_info();
3475 
3476   // main_thread points to the aboriginal thread
3477   Bsd::_main_thread = pthread_self();
3478 
3479   Bsd::clock_init();
3480   initial_time_count = javaTimeNanos();
3481 
3482 #ifdef __APPLE__
3483   // XXXDARWIN
3484   // Work around the unaligned VM callbacks in hotspot's
3485   // sharedRuntime. The callbacks don't use SSE2 instructions, and work on
3486   // Linux, Solaris, and FreeBSD. On Mac OS X, dyld (rightly so) enforces
3487   // alignment when doing symbol lookup. To work around this, we force early
3488   // binding of all symbols now, thus binding when alignment is known-good.
3489   _dyld_bind_fully_image_containing_address((const void *) &os::init);
3490 #endif
3491 }
3492 
3493 // To install functions for atexit system call
3494 extern "C" {
3495   static void perfMemory_exit_helper() {
3496     perfMemory_exit();
3497   }
3498 }
3499 
3500 // this is called _after_ the global arguments have been parsed
3501 jint os::init_2(void)
3502 {
3503   // Allocate a single page and mark it as readable for safepoint polling
3504   address polling_page = (address) ::mmap(NULL, Bsd::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
3505   guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page");
3506 
3507   os::set_polling_page(polling_page);
3508 
3509 #ifndef PRODUCT
3510   if (Verbose && PrintMiscellaneous)
3511     tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
3512 #endif
3513 
3514   if (!UseMembar) {
3515     address mem_serialize_page = (address) ::mmap(NULL, Bsd::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
3516     guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
3517     os::set_memory_serialize_page(mem_serialize_page);
3518 
3519 #ifndef PRODUCT
3520     if (Verbose && PrintMiscellaneous)
3521       tty->print("[Memory Serialize  Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
3522 #endif
3523   }
3524 
3525   // initialize suspend/resume support - must do this before signal_sets_init()
3526   if (SR_initialize() != 0) {
3527     perror("SR_initialize failed");
3528     return JNI_ERR;
3529   }
3530 
3531   Bsd::signal_sets_init();
3532   Bsd::install_signal_handlers();
3533 
3534   // Check minimum allowable stack size for thread creation and to initialize
3535   // the java system classes, including StackOverflowError - depends on page
3536   // size.  Add a page for compiler2 recursion in main thread.
3537   // Add in 2*BytesPerWord times page size to account for VM stack during
3538   // class initialization depending on 32 or 64 bit VM.
3539   os::Bsd::min_stack_allowed = MAX2(os::Bsd::min_stack_allowed,
3540             (size_t)(StackYellowPages+StackRedPages+StackShadowPages+
3541                     2*BytesPerWord COMPILER2_PRESENT(+1)) * Bsd::page_size());
3542 
3543   size_t threadStackSizeInBytes = ThreadStackSize * K;
3544   if (threadStackSizeInBytes != 0 &&
3545       threadStackSizeInBytes < os::Bsd::min_stack_allowed) {
3546         tty->print_cr("\nThe stack size specified is too small, "
3547                       "Specify at least %dk",
3548                       os::Bsd::min_stack_allowed/ K);
3549         return JNI_ERR;
3550   }
3551 
3552   // Make the stack size a multiple of the page size so that
3553   // the yellow/red zones can be guarded.
3554   JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
3555         vm_page_size()));
3556 
3557   if (MaxFDLimit) {
3558     // set the number of file descriptors to max. print out error
3559     // if getrlimit/setrlimit fails but continue regardless.
3560     struct rlimit nbr_files;
3561     int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
3562     if (status != 0) {
3563       if (PrintMiscellaneous && (Verbose || WizardMode))
3564         perror("os::init_2 getrlimit failed");
3565     } else {
3566       nbr_files.rlim_cur = nbr_files.rlim_max;
3567 
3568 #ifdef __APPLE__
3569       // Darwin returns RLIM_INFINITY for rlim_max, but fails with EINVAL if
3570       // you attempt to use RLIM_INFINITY. As per setrlimit(2), OPEN_MAX must
3571       // be used instead
3572       nbr_files.rlim_cur = MIN(OPEN_MAX, nbr_files.rlim_cur);
3573 #endif
3574 
3575       status = setrlimit(RLIMIT_NOFILE, &nbr_files);
3576       if (status != 0) {
3577         if (PrintMiscellaneous && (Verbose || WizardMode))
3578           perror("os::init_2 setrlimit failed");
3579       }
3580     }
3581   }
3582 
3583   // at-exit methods are called in the reverse order of their registration.
3584   // atexit functions are called on return from main or as a result of a
3585   // call to exit(3C). There can be only 32 of these functions registered
3586   // and atexit() does not set errno.
3587 
3588   if (PerfAllowAtExitRegistration) {
3589     // only register atexit functions if PerfAllowAtExitRegistration is set.
3590     // atexit functions can be delayed until process exit time, which
3591     // can be problematic for embedded VM situations. Embedded VMs should
3592     // call DestroyJavaVM() to assure that VM resources are released.
3593 
3594     // note: perfMemory_exit_helper atexit function may be removed in
3595     // the future if the appropriate cleanup code can be added to the
3596     // VM_Exit VMOperation's doit method.
3597     if (atexit(perfMemory_exit_helper) != 0) {
3598       warning("os::init2 atexit(perfMemory_exit_helper) failed");
3599     }
3600   }
3601 
3602   // initialize thread priority policy
3603   prio_init();
3604 
3605 #ifdef __APPLE__
3606   // dynamically link to objective c gc registration
3607   void *handleLibObjc = dlopen(OBJC_LIB, RTLD_LAZY);
3608   if (handleLibObjc != NULL) {
3609     objc_registerThreadWithCollectorFunction = (objc_registerThreadWithCollector_t) dlsym(handleLibObjc, OBJC_GCREGISTER);
3610   }
3611 #endif
3612 
3613   return JNI_OK;
3614 }
3615 
3616 // this is called at the end of vm_initialization
3617 void os::init_3(void) { }
3618 
3619 // Mark the polling page as unreadable
3620 void os::make_polling_page_unreadable(void) {
3621   if (!guard_memory((char*)_polling_page, Bsd::page_size()))
3622     fatal("Could not disable polling page");
3623 };
3624 
3625 // Mark the polling page as readable
3626 void os::make_polling_page_readable(void) {
3627   if (!bsd_mprotect((char *)_polling_page, Bsd::page_size(), PROT_READ)) {
3628     fatal("Could not enable polling page");
3629   }
3630 };
3631 
3632 int os::active_processor_count() {
3633   return _processor_count;
3634 }
3635 
3636 void os::set_native_thread_name(const char *name) {
3637 #if defined(__APPLE__) && MAC_OS_X_VERSION_MIN_REQUIRED > MAC_OS_X_VERSION_10_5
3638   // This is only supported in Snow Leopard and beyond
3639   if (name != NULL) {
3640     // Add a "Java: " prefix to the name
3641     char buf[MAXTHREADNAMESIZE];
3642     snprintf(buf, sizeof(buf), "Java: %s", name);
3643     pthread_setname_np(buf);
3644   }
3645 #endif
3646 }
3647 
3648 bool os::distribute_processes(uint length, uint* distribution) {
3649   // Not yet implemented.
3650   return false;
3651 }
3652 
3653 bool os::bind_to_processor(uint processor_id) {
3654   // Not yet implemented.
3655   return false;
3656 }
3657 
3658 void os::SuspendedThreadTask::internal_do_task() {
3659   if (do_suspend(_thread->osthread())) {
3660     SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
3661     do_task(context);
3662     do_resume(_thread->osthread());
3663   }
3664 }
3665 
3666 ///
3667 class PcFetcher : public os::SuspendedThreadTask {
3668 public:
3669   PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
3670   ExtendedPC result();
3671 protected:
3672   void do_task(const os::SuspendedThreadTaskContext& context);
3673 private:
3674   ExtendedPC _epc;
3675 };
3676 
3677 ExtendedPC PcFetcher::result() {
3678   guarantee(is_done(), "task is not done yet.");
3679   return _epc;
3680 }
3681 
3682 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
3683   Thread* thread = context.thread();
3684   OSThread* osthread = thread->osthread();
3685   if (osthread->ucontext() != NULL) {
3686     _epc = os::Bsd::ucontext_get_pc((ucontext_t *) context.ucontext());
3687   } else {
3688     // NULL context is unexpected, double-check this is the VMThread
3689     guarantee(thread->is_VM_thread(), "can only be called for VMThread");
3690   }
3691 }
3692 
3693 // Suspends the target using the signal mechanism and then grabs the PC before
3694 // resuming the target. Used by the flat-profiler only
3695 ExtendedPC os::get_thread_pc(Thread* thread) {
3696   // Make sure that it is called by the watcher for the VMThread
3697   assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
3698   assert(thread->is_VM_thread(), "Can only be called for VMThread");
3699 
3700   PcFetcher fetcher(thread);
3701   fetcher.run();
3702   return fetcher.result();
3703 }
3704 
3705 int os::Bsd::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
3706 {
3707   return pthread_cond_timedwait(_cond, _mutex, _abstime);
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       Disassembler::decode(begin, end, st);
3746     }
3747     return true;
3748   }
3749   return false;
3750 }
3751 
3752 ////////////////////////////////////////////////////////////////////////////////
3753 // misc
3754 
3755 // This does not do anything on Bsd. This is basically a hook for being
3756 // able to use structured exception handling (thread-local exception filters)
3757 // on, e.g., Win32.
3758 void
3759 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
3760                          JavaCallArguments* args, Thread* thread) {
3761   f(value, method, args, thread);
3762 }
3763 
3764 void os::print_statistics() {
3765 }
3766 
3767 int os::message_box(const char* title, const char* message) {
3768   int i;
3769   fdStream err(defaultStream::error_fd());
3770   for (i = 0; i < 78; i++) err.print_raw("=");
3771   err.cr();
3772   err.print_raw_cr(title);
3773   for (i = 0; i < 78; i++) err.print_raw("-");
3774   err.cr();
3775   err.print_raw_cr(message);
3776   for (i = 0; i < 78; i++) err.print_raw("=");
3777   err.cr();
3778 
3779   char buf[16];
3780   // Prevent process from exiting upon "read error" without consuming all CPU
3781   while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
3782 
3783   return buf[0] == 'y' || buf[0] == 'Y';
3784 }
3785 
3786 int os::stat(const char *path, struct stat *sbuf) {
3787   char pathbuf[MAX_PATH];
3788   if (strlen(path) > MAX_PATH - 1) {
3789     errno = ENAMETOOLONG;
3790     return -1;
3791   }
3792   os::native_path(strcpy(pathbuf, path));
3793   return ::stat(pathbuf, sbuf);
3794 }
3795 
3796 bool os::check_heap(bool force) {
3797   return true;
3798 }
3799 
3800 ATTRIBUTE_PRINTF(3, 0)
3801 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
3802   return ::vsnprintf(buf, count, format, args);
3803 }
3804 
3805 // Is a (classpath) directory empty?
3806 bool os::dir_is_empty(const char* path) {
3807   DIR *dir = NULL;
3808   struct dirent *ptr;
3809 
3810   dir = opendir(path);
3811   if (dir == NULL) return true;
3812 
3813   /* Scan the directory */
3814   bool result = true;
3815   char buf[sizeof(struct dirent) + MAX_PATH];
3816   while (result && (ptr = ::readdir(dir)) != NULL) {
3817     if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
3818       result = false;
3819     }
3820   }
3821   closedir(dir);
3822   return result;
3823 }
3824 
3825 // This code originates from JDK's sysOpen and open64_w
3826 // from src/solaris/hpi/src/system_md.c
3827 
3828 #ifndef O_DELETE
3829 #define O_DELETE 0x10000
3830 #endif
3831 
3832 // Open a file. Unlink the file immediately after open returns
3833 // if the specified oflag has the O_DELETE flag set.
3834 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
3835 
3836 int os::open(const char *path, int oflag, int mode) {
3837 
3838   if (strlen(path) > MAX_PATH - 1) {
3839     errno = ENAMETOOLONG;
3840     return -1;
3841   }
3842   int fd;
3843   int o_delete = (oflag & O_DELETE);
3844   oflag = oflag & ~O_DELETE;
3845 
3846   fd = ::open(path, oflag, mode);
3847   if (fd == -1) return -1;
3848 
3849   //If the open succeeded, the file might still be a directory
3850   {
3851     struct stat buf;
3852     int ret = ::fstat(fd, &buf);
3853     int st_mode = buf.st_mode;
3854 
3855     if (ret != -1) {
3856       if ((st_mode & S_IFMT) == S_IFDIR) {
3857         errno = EISDIR;
3858         ::close(fd);
3859         return -1;
3860       }
3861     } else {
3862       ::close(fd);
3863       return -1;
3864     }
3865   }
3866 
3867     /*
3868      * All file descriptors that are opened in the JVM and not
3869      * specifically destined for a subprocess should have the
3870      * close-on-exec flag set.  If we don't set it, then careless 3rd
3871      * party native code might fork and exec without closing all
3872      * appropriate file descriptors (e.g. as we do in closeDescriptors in
3873      * UNIXProcess.c), and this in turn might:
3874      *
3875      * - cause end-of-file to fail to be detected on some file
3876      *   descriptors, resulting in mysterious hangs, or
3877      *
3878      * - might cause an fopen in the subprocess to fail on a system
3879      *   suffering from bug 1085341.
3880      *
3881      * (Yes, the default setting of the close-on-exec flag is a Unix
3882      * design flaw)
3883      *
3884      * See:
3885      * 1085341: 32-bit stdio routines should support file descriptors >255
3886      * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
3887      * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
3888      */
3889 #ifdef FD_CLOEXEC
3890     {
3891         int flags = ::fcntl(fd, F_GETFD);
3892         if (flags != -1)
3893             ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
3894     }
3895 #endif
3896 
3897   if (o_delete != 0) {
3898     ::unlink(path);
3899   }
3900   return fd;
3901 }
3902 
3903 
3904 // create binary file, rewriting existing file if required
3905 int os::create_binary_file(const char* path, bool rewrite_existing) {
3906   int oflags = O_WRONLY | O_CREAT;
3907   if (!rewrite_existing) {
3908     oflags |= O_EXCL;
3909   }
3910   return ::open(path, oflags, S_IREAD | S_IWRITE);
3911 }
3912 
3913 // return current position of file pointer
3914 jlong os::current_file_offset(int fd) {
3915   return (jlong)::lseek(fd, (off_t)0, SEEK_CUR);
3916 }
3917 
3918 // move file pointer to the specified offset
3919 jlong os::seek_to_file_offset(int fd, jlong offset) {
3920   return (jlong)::lseek(fd, (off_t)offset, SEEK_SET);
3921 }
3922 
3923 // This code originates from JDK's sysAvailable
3924 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
3925 
3926 int os::available(int fd, jlong *bytes) {
3927   jlong cur, end;
3928   int mode;
3929   struct stat buf;
3930 
3931   if (::fstat(fd, &buf) >= 0) {
3932     mode = buf.st_mode;
3933     if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
3934       /*
3935       * XXX: is the following call interruptible? If so, this might
3936       * need to go through the INTERRUPT_IO() wrapper as for other
3937       * blocking, interruptible calls in this file.
3938       */
3939       int n;
3940       if (::ioctl(fd, FIONREAD, &n) >= 0) {
3941         *bytes = n;
3942         return 1;
3943       }
3944     }
3945   }
3946   if ((cur = ::lseek(fd, 0L, SEEK_CUR)) == -1) {
3947     return 0;
3948   } else if ((end = ::lseek(fd, 0L, SEEK_END)) == -1) {
3949     return 0;
3950   } else if (::lseek(fd, cur, SEEK_SET) == -1) {
3951     return 0;
3952   }
3953   *bytes = end - cur;
3954   return 1;
3955 }
3956 
3957 int os::socket_available(int fd, jint *pbytes) {
3958    if (fd < 0)
3959      return OS_OK;
3960 
3961    int ret;
3962 
3963    RESTARTABLE(::ioctl(fd, FIONREAD, pbytes), ret);
3964 
3965    //%% note ioctl can return 0 when successful, JVM_SocketAvailable
3966    // is expected to return 0 on failure and 1 on success to the jdk.
3967 
3968    return (ret == OS_ERR) ? 0 : 1;
3969 }
3970 
3971 // Map a block of memory.
3972 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
3973                      char *addr, size_t bytes, bool read_only,
3974                      bool allow_exec) {
3975   int prot;
3976   int flags;
3977 
3978   if (read_only) {
3979     prot = PROT_READ;
3980     flags = MAP_SHARED;
3981   } else {
3982     prot = PROT_READ | PROT_WRITE;
3983     flags = MAP_PRIVATE;
3984   }
3985 
3986   if (allow_exec) {
3987     prot |= PROT_EXEC;
3988   }
3989 
3990   if (addr != NULL) {
3991     flags |= MAP_FIXED;
3992   }
3993 
3994   char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
3995                                      fd, file_offset);
3996   if (mapped_address == MAP_FAILED) {
3997     return NULL;
3998   }
3999   return mapped_address;
4000 }
4001 
4002 
4003 // Remap a block of memory.
4004 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
4005                        char *addr, size_t bytes, bool read_only,
4006                        bool allow_exec) {
4007   // same as map_memory() on this OS
4008   return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4009                         allow_exec);
4010 }
4011 
4012 
4013 // Unmap a block of memory.
4014 bool os::pd_unmap_memory(char* addr, size_t bytes) {
4015   return munmap(addr, bytes) == 0;
4016 }
4017 
4018 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4019 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4020 // of a thread.
4021 //
4022 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4023 // the fast estimate available on the platform.
4024 
4025 jlong os::current_thread_cpu_time() {
4026 #ifdef __APPLE__
4027   return os::thread_cpu_time(Thread::current(), true /* user + sys */);
4028 #else
4029   Unimplemented();
4030   return 0;
4031 #endif
4032 }
4033 
4034 jlong os::thread_cpu_time(Thread* thread) {
4035 #ifdef __APPLE__
4036   return os::thread_cpu_time(thread, true /* user + sys */);
4037 #else
4038   Unimplemented();
4039   return 0;
4040 #endif
4041 }
4042 
4043 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4044 #ifdef __APPLE__
4045   return os::thread_cpu_time(Thread::current(), user_sys_cpu_time);
4046 #else
4047   Unimplemented();
4048   return 0;
4049 #endif
4050 }
4051 
4052 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4053 #ifdef __APPLE__
4054   struct thread_basic_info tinfo;
4055   mach_msg_type_number_t tcount = THREAD_INFO_MAX;
4056   kern_return_t kr;
4057   thread_t mach_thread;
4058 
4059   mach_thread = thread->osthread()->thread_id();
4060   kr = thread_info(mach_thread, THREAD_BASIC_INFO, (thread_info_t)&tinfo, &tcount);
4061   if (kr != KERN_SUCCESS)
4062     return -1;
4063 
4064   if (user_sys_cpu_time) {
4065     jlong nanos;
4066     nanos = ((jlong) tinfo.system_time.seconds + tinfo.user_time.seconds) * (jlong)1000000000;
4067     nanos += ((jlong) tinfo.system_time.microseconds + (jlong) tinfo.user_time.microseconds) * (jlong)1000;
4068     return nanos;
4069   } else {
4070     return ((jlong)tinfo.user_time.seconds * 1000000000) + ((jlong)tinfo.user_time.microseconds * (jlong)1000);
4071   }
4072 #else
4073   Unimplemented();
4074   return 0;
4075 #endif
4076 }
4077 
4078 
4079 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4080   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
4081   info_ptr->may_skip_backward = false;     // elapsed time not wall time
4082   info_ptr->may_skip_forward = false;      // elapsed time not wall time
4083   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
4084 }
4085 
4086 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4087   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
4088   info_ptr->may_skip_backward = false;     // elapsed time not wall time
4089   info_ptr->may_skip_forward = false;      // elapsed time not wall time
4090   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
4091 }
4092 
4093 bool os::is_thread_cpu_time_supported() {
4094 #ifdef __APPLE__
4095   return true;
4096 #else
4097   return false;
4098 #endif
4099 }
4100 
4101 // System loadavg support.  Returns -1 if load average cannot be obtained.
4102 // Bsd doesn't yet have a (official) notion of processor sets,
4103 // so just return the system wide load average.
4104 int os::loadavg(double loadavg[], int nelem) {
4105   return ::getloadavg(loadavg, nelem);
4106 }
4107 
4108 void os::pause() {
4109   char filename[MAX_PATH];
4110   if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4111     jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4112   } else {
4113     jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4114   }
4115 
4116   int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4117   if (fd != -1) {
4118     struct stat buf;
4119     ::close(fd);
4120     while (::stat(filename, &buf) == 0) {
4121       (void)::poll(NULL, 0, 100);
4122     }
4123   } else {
4124     jio_fprintf(stderr,
4125       "Could not open pause file '%s', continuing immediately.\n", filename);
4126   }
4127 }
4128 
4129 
4130 // Refer to the comments in os_solaris.cpp park-unpark.
4131 //
4132 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4133 // hang indefinitely.  For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4134 // For specifics regarding the bug see GLIBC BUGID 261237 :
4135 //    http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4136 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4137 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4138 // is used.  (The simple C test-case provided in the GLIBC bug report manifests the
4139 // hang).  The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4140 // and monitorenter when we're using 1-0 locking.  All those operations may result in
4141 // calls to pthread_cond_timedwait().  Using LD_ASSUME_KERNEL to use an older version
4142 // of libpthread avoids the problem, but isn't practical.
4143 //
4144 // Possible remedies:
4145 //
4146 // 1.   Establish a minimum relative wait time.  50 to 100 msecs seems to work.
4147 //      This is palliative and probabilistic, however.  If the thread is preempted
4148 //      between the call to compute_abstime() and pthread_cond_timedwait(), more
4149 //      than the minimum period may have passed, and the abstime may be stale (in the
4150 //      past) resultin in a hang.   Using this technique reduces the odds of a hang
4151 //      but the JVM is still vulnerable, particularly on heavily loaded systems.
4152 //
4153 // 2.   Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4154 //      of the usual flag-condvar-mutex idiom.  The write side of the pipe is set
4155 //      NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4156 //      reduces to poll()+read().  This works well, but consumes 2 FDs per extant
4157 //      thread.
4158 //
4159 // 3.   Embargo pthread_cond_timedwait() and implement a native "chron" thread
4160 //      that manages timeouts.  We'd emulate pthread_cond_timedwait() by enqueuing
4161 //      a timeout request to the chron thread and then blocking via pthread_cond_wait().
4162 //      This also works well.  In fact it avoids kernel-level scalability impediments
4163 //      on certain platforms that don't handle lots of active pthread_cond_timedwait()
4164 //      timers in a graceful fashion.
4165 //
4166 // 4.   When the abstime value is in the past it appears that control returns
4167 //      correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4168 //      Subsequent timedwait/wait calls may hang indefinitely.  Given that, we
4169 //      can avoid the problem by reinitializing the condvar -- by cond_destroy()
4170 //      followed by cond_init() -- after all calls to pthread_cond_timedwait().
4171 //      It may be possible to avoid reinitialization by checking the return
4172 //      value from pthread_cond_timedwait().  In addition to reinitializing the
4173 //      condvar we must establish the invariant that cond_signal() is only called
4174 //      within critical sections protected by the adjunct mutex.  This prevents
4175 //      cond_signal() from "seeing" a condvar that's in the midst of being
4176 //      reinitialized or that is corrupt.  Sadly, this invariant obviates the
4177 //      desirable signal-after-unlock optimization that avoids futile context switching.
4178 //
4179 //      I'm also concerned that some versions of NTPL might allocate an auxilliary
4180 //      structure when a condvar is used or initialized.  cond_destroy()  would
4181 //      release the helper structure.  Our reinitialize-after-timedwait fix
4182 //      put excessive stress on malloc/free and locks protecting the c-heap.
4183 //
4184 // We currently use (4).  See the WorkAroundNTPLTimedWaitHang flag.
4185 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4186 // and only enabling the work-around for vulnerable environments.
4187 
4188 // utility to compute the abstime argument to timedwait:
4189 // millis is the relative timeout time
4190 // abstime will be the absolute timeout time
4191 // TODO: replace compute_abstime() with unpackTime()
4192 
4193 static struct timespec* compute_abstime(struct timespec* abstime, jlong millis) {
4194   if (millis < 0)  millis = 0;
4195   struct timeval now;
4196   int status = gettimeofday(&now, NULL);
4197   assert(status == 0, "gettimeofday");
4198   jlong seconds = millis / 1000;
4199   millis %= 1000;
4200   if (seconds > 50000000) { // see man cond_timedwait(3T)
4201     seconds = 50000000;
4202   }
4203   abstime->tv_sec = now.tv_sec  + seconds;
4204   long       usec = now.tv_usec + millis * 1000;
4205   if (usec >= 1000000) {
4206     abstime->tv_sec += 1;
4207     usec -= 1000000;
4208   }
4209   abstime->tv_nsec = usec * 1000;
4210   return abstime;
4211 }
4212 
4213 void os::PlatformEvent::park() {       // AKA "down()"
4214   // Invariant: Only the thread associated with the Event/PlatformEvent
4215   // may call park().
4216   // TODO: assert that _Assoc != NULL or _Assoc == Self
4217   assert(_nParked == 0, "invariant");
4218 
4219   int v;
4220   for (;;) {
4221       v = _Event;
4222       if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
4223   }
4224   guarantee(v >= 0, "invariant");
4225   if (v == 0) {
4226      // Do this the hard way by blocking ...
4227      int status = pthread_mutex_lock(_mutex);
4228      assert_status(status == 0, status, "mutex_lock");
4229      guarantee(_nParked == 0, "invariant");
4230      ++_nParked;
4231      while (_Event < 0) {
4232         status = pthread_cond_wait(_cond, _mutex);
4233         // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
4234         // Treat this the same as if the wait was interrupted
4235         if (status == ETIMEDOUT) { status = EINTR; }
4236         assert_status(status == 0 || status == EINTR, status, "cond_wait");
4237      }
4238      --_nParked;
4239 
4240     _Event = 0;
4241      status = pthread_mutex_unlock(_mutex);
4242      assert_status(status == 0, status, "mutex_unlock");
4243     // Paranoia to ensure our locked and lock-free paths interact
4244     // correctly with each other.
4245     OrderAccess::fence();
4246   }
4247   guarantee(_Event >= 0, "invariant");
4248 }
4249 
4250 int os::PlatformEvent::park(jlong millis) {
4251   guarantee(_nParked == 0, "invariant");
4252 
4253   int v;
4254   for (;;) {
4255       v = _Event;
4256       if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
4257   }
4258   guarantee(v >= 0, "invariant");
4259   if (v != 0) return OS_OK;
4260 
4261   // We do this the hard way, by blocking the thread.
4262   // Consider enforcing a minimum timeout value.
4263   struct timespec abst;
4264   compute_abstime(&abst, millis);
4265 
4266   int ret = OS_TIMEOUT;
4267   int status = pthread_mutex_lock(_mutex);
4268   assert_status(status == 0, status, "mutex_lock");
4269   guarantee(_nParked == 0, "invariant");
4270   ++_nParked;
4271 
4272   // Object.wait(timo) will return because of
4273   // (a) notification
4274   // (b) timeout
4275   // (c) thread.interrupt
4276   //
4277   // Thread.interrupt and object.notify{All} both call Event::set.
4278   // That is, we treat thread.interrupt as a special case of notification.
4279   // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false.
4280   // We assume all ETIME returns are valid.
4281   //
4282   // TODO: properly differentiate simultaneous notify+interrupt.
4283   // In that case, we should propagate the notify to another waiter.
4284 
4285   while (_Event < 0) {
4286     status = os::Bsd::safe_cond_timedwait(_cond, _mutex, &abst);
4287     if (status != 0 && WorkAroundNPTLTimedWaitHang) {
4288       pthread_cond_destroy(_cond);
4289       pthread_cond_init(_cond, NULL);
4290     }
4291     assert_status(status == 0 || status == EINTR ||
4292                   status == ETIMEDOUT,
4293                   status, "cond_timedwait");
4294     if (!FilterSpuriousWakeups) break;                 // previous semantics
4295     if (status == ETIMEDOUT) break;
4296     // We consume and ignore EINTR and spurious wakeups.
4297   }
4298   --_nParked;
4299   if (_Event >= 0) {
4300      ret = OS_OK;
4301   }
4302   _Event = 0;
4303   status = pthread_mutex_unlock(_mutex);
4304   assert_status(status == 0, status, "mutex_unlock");
4305   assert(_nParked == 0, "invariant");
4306   // Paranoia to ensure our locked and lock-free paths interact
4307   // correctly with each other.
4308   OrderAccess::fence();
4309   return ret;
4310 }
4311 
4312 void os::PlatformEvent::unpark() {
4313   // Transitions for _Event:
4314   //    0 :=> 1
4315   //    1 :=> 1
4316   //   -1 :=> either 0 or 1; must signal target thread
4317   //          That is, we can safely transition _Event from -1 to either
4318   //          0 or 1.
4319   // See also: "Semaphores in Plan 9" by Mullender & Cox
4320   //
4321   // Note: Forcing a transition from "-1" to "1" on an unpark() means
4322   // that it will take two back-to-back park() calls for the owning
4323   // thread to block. This has the benefit of forcing a spurious return
4324   // from the first park() call after an unpark() call which will help
4325   // shake out uses of park() and unpark() without condition variables.
4326 
4327   if (Atomic::xchg(1, &_Event) >= 0) return;
4328 
4329   // Wait for the thread associated with the event to vacate
4330   int status = pthread_mutex_lock(_mutex);
4331   assert_status(status == 0, status, "mutex_lock");
4332   int AnyWaiters = _nParked;
4333   assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
4334   if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
4335     AnyWaiters = 0;
4336     pthread_cond_signal(_cond);
4337   }
4338   status = pthread_mutex_unlock(_mutex);
4339   assert_status(status == 0, status, "mutex_unlock");
4340   if (AnyWaiters != 0) {
4341     status = pthread_cond_signal(_cond);
4342     assert_status(status == 0, status, "cond_signal");
4343   }
4344 
4345   // Note that we signal() _after dropping the lock for "immortal" Events.
4346   // This is safe and avoids a common class of  futile wakeups.  In rare
4347   // circumstances this can cause a thread to return prematurely from
4348   // cond_{timed}wait() but the spurious wakeup is benign and the victim will
4349   // simply re-test the condition and re-park itself.
4350 }
4351 
4352 
4353 // JSR166
4354 // -------------------------------------------------------
4355 
4356 /*
4357  * The solaris and bsd implementations of park/unpark are fairly
4358  * conservative for now, but can be improved. They currently use a
4359  * mutex/condvar pair, plus a a count.
4360  * Park decrements count if > 0, else does a condvar wait.  Unpark
4361  * sets count to 1 and signals condvar.  Only one thread ever waits
4362  * on the condvar. Contention seen when trying to park implies that someone
4363  * is unparking you, so don't wait. And spurious returns are fine, so there
4364  * is no need to track notifications.
4365  */
4366 
4367 #define MAX_SECS 100000000
4368 /*
4369  * This code is common to bsd and solaris and will be moved to a
4370  * common place in dolphin.
4371  *
4372  * The passed in time value is either a relative time in nanoseconds
4373  * or an absolute time in milliseconds. Either way it has to be unpacked
4374  * into suitable seconds and nanoseconds components and stored in the
4375  * given timespec structure.
4376  * Given time is a 64-bit value and the time_t used in the timespec is only
4377  * a signed-32-bit value (except on 64-bit Bsd) we have to watch for
4378  * overflow if times way in the future are given. Further on Solaris versions
4379  * prior to 10 there is a restriction (see cond_timedwait) that the specified
4380  * number of seconds, in abstime, is less than current_time  + 100,000,000.
4381  * As it will be 28 years before "now + 100000000" will overflow we can
4382  * ignore overflow and just impose a hard-limit on seconds using the value
4383  * of "now + 100,000,000". This places a limit on the timeout of about 3.17
4384  * years from "now".
4385  */
4386 
4387 static void unpackTime(struct timespec* absTime, bool isAbsolute, jlong time) {
4388   assert(time > 0, "convertTime");
4389 
4390   struct timeval now;
4391   int status = gettimeofday(&now, NULL);
4392   assert(status == 0, "gettimeofday");
4393 
4394   time_t max_secs = now.tv_sec + MAX_SECS;
4395 
4396   if (isAbsolute) {
4397     jlong secs = time / 1000;
4398     if (secs > max_secs) {
4399       absTime->tv_sec = max_secs;
4400     }
4401     else {
4402       absTime->tv_sec = secs;
4403     }
4404     absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
4405   }
4406   else {
4407     jlong secs = time / NANOSECS_PER_SEC;
4408     if (secs >= MAX_SECS) {
4409       absTime->tv_sec = max_secs;
4410       absTime->tv_nsec = 0;
4411     }
4412     else {
4413       absTime->tv_sec = now.tv_sec + secs;
4414       absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
4415       if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
4416         absTime->tv_nsec -= NANOSECS_PER_SEC;
4417         ++absTime->tv_sec; // note: this must be <= max_secs
4418       }
4419     }
4420   }
4421   assert(absTime->tv_sec >= 0, "tv_sec < 0");
4422   assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
4423   assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
4424   assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
4425 }
4426 
4427 void Parker::park(bool isAbsolute, jlong time) {
4428   // Ideally we'd do something useful while spinning, such
4429   // as calling unpackTime().
4430 
4431   // Optional fast-path check:
4432   // Return immediately if a permit is available.
4433   // We depend on Atomic::xchg() having full barrier semantics
4434   // since we are doing a lock-free update to _counter.
4435   if (Atomic::xchg(0, &_counter) > 0) return;
4436 
4437   Thread* thread = Thread::current();
4438   assert(thread->is_Java_thread(), "Must be JavaThread");
4439   JavaThread *jt = (JavaThread *)thread;
4440 
4441   // Optional optimization -- avoid state transitions if there's an interrupt pending.
4442   // Check interrupt before trying to wait
4443   if (Thread::is_interrupted(thread, false)) {
4444     return;
4445   }
4446 
4447   // Next, demultiplex/decode time arguments
4448   struct timespec absTime;
4449   if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
4450     return;
4451   }
4452   if (time > 0) {
4453     unpackTime(&absTime, isAbsolute, time);
4454   }
4455 
4456 
4457   // Enter safepoint region
4458   // Beware of deadlocks such as 6317397.
4459   // The per-thread Parker:: mutex is a classic leaf-lock.
4460   // In particular a thread must never block on the Threads_lock while
4461   // holding the Parker:: mutex.  If safepoints are pending both the
4462   // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
4463   ThreadBlockInVM tbivm(jt);
4464 
4465   // Don't wait if cannot get lock since interference arises from
4466   // unblocking.  Also. check interrupt before trying wait
4467   if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
4468     return;
4469   }
4470 
4471   int status;
4472   if (_counter > 0)  { // no wait needed
4473     _counter = 0;
4474     status = pthread_mutex_unlock(_mutex);
4475     assert(status == 0, "invariant");
4476     // Paranoia to ensure our locked and lock-free paths interact
4477     // correctly with each other and Java-level accesses.
4478     OrderAccess::fence();
4479     return;
4480   }
4481 
4482 #ifdef ASSERT
4483   // Don't catch signals while blocked; let the running threads have the signals.
4484   // (This allows a debugger to break into the running thread.)
4485   sigset_t oldsigs;
4486   sigset_t* allowdebug_blocked = os::Bsd::allowdebug_blocked_signals();
4487   pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
4488 #endif
4489 
4490   OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
4491   jt->set_suspend_equivalent();
4492   // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
4493 
4494   if (time == 0) {
4495     status = pthread_cond_wait(_cond, _mutex);
4496   } else {
4497     status = os::Bsd::safe_cond_timedwait(_cond, _mutex, &absTime);
4498     if (status != 0 && WorkAroundNPTLTimedWaitHang) {
4499       pthread_cond_destroy(_cond);
4500       pthread_cond_init(_cond, NULL);
4501     }
4502   }
4503   assert_status(status == 0 || status == EINTR ||
4504                 status == ETIMEDOUT,
4505                 status, "cond_timedwait");
4506 
4507 #ifdef ASSERT
4508   pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
4509 #endif
4510 
4511   _counter = 0;
4512   status = pthread_mutex_unlock(_mutex);
4513   assert_status(status == 0, status, "invariant");
4514   // Paranoia to ensure our locked and lock-free paths interact
4515   // correctly with each other and Java-level accesses.
4516   OrderAccess::fence();
4517 
4518   // If externally suspended while waiting, re-suspend
4519   if (jt->handle_special_suspend_equivalent_condition()) {
4520     jt->java_suspend_self();
4521   }
4522 }
4523 
4524 void Parker::unpark() {
4525   int status = pthread_mutex_lock(_mutex);
4526   assert(status == 0, "invariant");
4527   const int s = _counter;
4528   _counter = 1;
4529   if (s < 1) {
4530      if (WorkAroundNPTLTimedWaitHang) {
4531         status = pthread_cond_signal(_cond);
4532         assert(status == 0, "invariant");
4533         status = pthread_mutex_unlock(_mutex);
4534         assert(status == 0, "invariant");
4535      } else {
4536         status = pthread_mutex_unlock(_mutex);
4537         assert(status == 0, "invariant");
4538         status = pthread_cond_signal(_cond);
4539         assert(status == 0, "invariant");
4540      }
4541   } else {
4542     pthread_mutex_unlock(_mutex);
4543     assert(status == 0, "invariant");
4544   }
4545 }
4546 
4547 
4548 /* Darwin has no "environ" in a dynamic library. */
4549 #ifdef __APPLE__
4550 #include <crt_externs.h>
4551 #define environ (*_NSGetEnviron())
4552 #else
4553 extern char** environ;
4554 #endif
4555 
4556 // Run the specified command in a separate process. Return its exit value,
4557 // or -1 on failure (e.g. can't fork a new process).
4558 // Unlike system(), this function can be called from signal handler. It
4559 // doesn't block SIGINT et al.
4560 int os::fork_and_exec(char* cmd) {
4561   const char * argv[4] = {"sh", "-c", cmd, NULL};
4562 
4563   // fork() in BsdThreads/NPTL is not async-safe. It needs to run
4564   // pthread_atfork handlers and reset pthread library. All we need is a
4565   // separate process to execve. Make a direct syscall to fork process.
4566   // On IA64 there's no fork syscall, we have to use fork() and hope for
4567   // the best...
4568   pid_t pid = fork();
4569 
4570   if (pid < 0) {
4571     // fork failed
4572     return -1;
4573 
4574   } else if (pid == 0) {
4575     // child process
4576 
4577     // execve() in BsdThreads will call pthread_kill_other_threads_np()
4578     // first to kill every thread on the thread list. Because this list is
4579     // not reset by fork() (see notes above), execve() will instead kill
4580     // every thread in the parent process. We know this is the only thread
4581     // in the new process, so make a system call directly.
4582     // IA64 should use normal execve() from glibc to match the glibc fork()
4583     // above.
4584     execve("/bin/sh", (char* const*)argv, environ);
4585 
4586     // execve failed
4587     _exit(-1);
4588 
4589   } else  {
4590     // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
4591     // care about the actual exit code, for now.
4592 
4593     int status;
4594 
4595     // Wait for the child process to exit.  This returns immediately if
4596     // the child has already exited. */
4597     while (waitpid(pid, &status, 0) < 0) {
4598         switch (errno) {
4599         case ECHILD: return 0;
4600         case EINTR: break;
4601         default: return -1;
4602         }
4603     }
4604 
4605     if (WIFEXITED(status)) {
4606        // The child exited normally; get its exit code.
4607        return WEXITSTATUS(status);
4608     } else if (WIFSIGNALED(status)) {
4609        // The child exited because of a signal
4610        // The best value to return is 0x80 + signal number,
4611        // because that is what all Unix shells do, and because
4612        // it allows callers to distinguish between process exit and
4613        // process death by signal.
4614        return 0x80 + WTERMSIG(status);
4615     } else {
4616        // Unknown exit code; pass it through
4617        return status;
4618     }
4619   }
4620 }
4621 
4622 // is_headless_jre()
4623 //
4624 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
4625 // in order to report if we are running in a headless jre
4626 //
4627 // Since JDK8 xawt/libmawt.so was moved into the same directory
4628 // as libawt.so, and renamed libawt_xawt.so
4629 //
4630 bool os::is_headless_jre() {
4631 #ifdef __APPLE__
4632     // We no longer build headless-only on Mac OS X
4633     return false;
4634 #else
4635     struct stat statbuf;
4636     char buf[MAXPATHLEN];
4637     char libmawtpath[MAXPATHLEN];
4638     const char *xawtstr  = "/xawt/libmawt" JNI_LIB_SUFFIX;
4639     const char *new_xawtstr = "/libawt_xawt" JNI_LIB_SUFFIX;
4640     char *p;
4641 
4642     // Get path to libjvm.so
4643     os::jvm_path(buf, sizeof(buf));
4644 
4645     // Get rid of libjvm.so
4646     p = strrchr(buf, '/');
4647     if (p == NULL) return false;
4648     else *p = '\0';
4649 
4650     // Get rid of client or server
4651     p = strrchr(buf, '/');
4652     if (p == NULL) return false;
4653     else *p = '\0';
4654 
4655     // check xawt/libmawt.so
4656     strcpy(libmawtpath, buf);
4657     strcat(libmawtpath, xawtstr);
4658     if (::stat(libmawtpath, &statbuf) == 0) return false;
4659 
4660     // check libawt_xawt.so
4661     strcpy(libmawtpath, buf);
4662     strcat(libmawtpath, new_xawtstr);
4663     if (::stat(libmawtpath, &statbuf) == 0) return false;
4664 
4665     return true;
4666 #endif
4667 }
4668 
4669 // Get the default path to the core file
4670 // Returns the length of the string
4671 int os::get_core_path(char* buffer, size_t bufferSize) {
4672   int n = jio_snprintf(buffer, bufferSize, "/cores");
4673 
4674   // Truncate if theoretical string was longer than bufferSize
4675   n = MIN2(n, (int)bufferSize);
4676 
4677   return n;
4678 }
4679 
4680 #ifndef PRODUCT
4681 void TestReserveMemorySpecial_test() {
4682   // No tests available for this platform
4683 }
4684 #endif