1 /*
   2 * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "utilities/globalDefinitions.hpp"
  26 #include "prims/jvm.h"
  27 #include "runtime/frame.inline.hpp"
  28 #include "runtime/os.hpp"
  29 #include "utilities/vmError.hpp"
  30 
  31 #include <signal.h>
  32 #include <unistd.h>
  33 #include <sys/resource.h>
  34 #include <sys/utsname.h>
  35 #include <pthread.h>
  36 #include <signal.h>
  37 
  38 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  39 
  40 // Todo: provide a os::get_max_process_id() or similar. Number of processes
  41 // may have been configured, can be read more accurately from proc fs etc.
  42 #ifndef MAX_PID
  43 #define MAX_PID INT_MAX
  44 #endif
  45 #define IS_VALID_PID(p) (p > 0 && p < MAX_PID)
  46 
  47 // Check core dump limit and report possible place where core can be found
  48 void os::check_or_create_dump(void* exceptionRecord, void* contextRecord, char* buffer, size_t bufferSize) {
  49   int n;
  50   struct rlimit rlim;
  51   bool success;
  52 
  53   n = get_core_path(buffer, bufferSize);
  54 
  55   if (getrlimit(RLIMIT_CORE, &rlim) != 0) {
  56     jio_snprintf(buffer + n, bufferSize - n, "/core or core.%d (may not exist)", current_process_id());
  57     success = true;
  58   } else {
  59     switch(rlim.rlim_cur) {
  60       case RLIM_INFINITY:
  61         jio_snprintf(buffer + n, bufferSize - n, "/core or core.%d", current_process_id());
  62         success = true;
  63         break;
  64       case 0:
  65         jio_snprintf(buffer, bufferSize, "Core dumps have been disabled. To enable core dumping, try \"ulimit -c unlimited\" before starting Java again");
  66         success = false;
  67         break;
  68       default:
  69         jio_snprintf(buffer + n, bufferSize - n, "/core or core.%d (max size %lu kB). To ensure a full core dump, try \"ulimit -c unlimited\" before starting Java again", current_process_id(), (unsigned long)(rlim.rlim_cur >> 10));
  70         success = true;
  71         break;
  72     }
  73   }
  74   VMError::report_coredump_status(buffer, success);
  75 }
  76 
  77 int os::get_native_stack(address* stack, int frames, int toSkip) {
  78 #ifdef _NMT_NOINLINE_
  79   toSkip++;
  80 #endif
  81 
  82   int frame_idx = 0;
  83   int num_of_frames;  // number of frames captured
  84   frame fr = os::current_frame();
  85   while (fr.pc() && frame_idx < frames) {
  86     if (toSkip > 0) {
  87       toSkip --;
  88     } else {
  89       stack[frame_idx ++] = fr.pc();
  90     }
  91     if (fr.fp() == NULL || os::is_first_C_frame(&fr)
  92         ||fr.sender_pc() == NULL || fr.cb() != NULL) break;
  93 
  94     if (fr.sender_pc() && !os::is_first_C_frame(&fr)) {
  95       fr = os::get_sender_for_C_frame(&fr);
  96     } else {
  97       break;
  98     }
  99   }
 100   num_of_frames = frame_idx;
 101   for (; frame_idx < frames; frame_idx ++) {
 102     stack[frame_idx] = NULL;
 103   }
 104 
 105   return num_of_frames;
 106 }
 107 
 108 
 109 bool os::unsetenv(const char* name) {
 110   assert(name != NULL, "Null pointer");
 111   return (::unsetenv(name) == 0);
 112 }
 113 
 114 int os::get_last_error() {
 115   return errno;
 116 }
 117 
 118 bool os::is_debugger_attached() {
 119   // not implemented
 120   return false;
 121 }
 122 
 123 void os::wait_for_keypress_at_exit(void) {
 124   // don't do anything on posix platforms
 125   return;
 126 }
 127 
 128 // Multiple threads can race in this code, and can remap over each other with MAP_FIXED,
 129 // so on posix, unmap the section at the start and at the end of the chunk that we mapped
 130 // rather than unmapping and remapping the whole chunk to get requested alignment.
 131 char* os::reserve_memory_aligned(size_t size, size_t alignment) {
 132   assert((alignment & (os::vm_allocation_granularity() - 1)) == 0,
 133       "Alignment must be a multiple of allocation granularity (page size)");
 134   assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned");
 135 
 136   size_t extra_size = size + alignment;
 137   assert(extra_size >= size, "overflow, size is too large to allow alignment");
 138 
 139   char* extra_base = os::reserve_memory(extra_size, NULL, alignment);
 140 
 141   if (extra_base == NULL) {
 142     return NULL;
 143   }
 144 
 145   // Do manual alignment
 146   char* aligned_base = (char*) align_size_up((uintptr_t) extra_base, alignment);
 147 
 148   // [  |                                       |  ]
 149   // ^ extra_base
 150   //    ^ extra_base + begin_offset == aligned_base
 151   //     extra_base + begin_offset + size       ^
 152   //                       extra_base + extra_size ^
 153   // |<>| == begin_offset
 154   //                              end_offset == |<>|
 155   size_t begin_offset = aligned_base - extra_base;
 156   size_t end_offset = (extra_base + extra_size) - (aligned_base + size);
 157 
 158   if (begin_offset > 0) {
 159       os::release_memory(extra_base, begin_offset);
 160   }
 161 
 162   if (end_offset > 0) {
 163       os::release_memory(extra_base + begin_offset + size, end_offset);
 164   }
 165 
 166   return aligned_base;
 167 }
 168 
 169 void os::Posix::print_load_average(outputStream* st) {
 170   st->print("load average:");
 171   double loadavg[3];
 172   os::loadavg(loadavg, 3);
 173   st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
 174   st->cr();
 175 }
 176 
 177 void os::Posix::print_rlimit_info(outputStream* st) {
 178   st->print("rlimit:");
 179   struct rlimit rlim;
 180 
 181   st->print(" STACK ");
 182   getrlimit(RLIMIT_STACK, &rlim);
 183   if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
 184   else st->print("%uk", rlim.rlim_cur >> 10);
 185 
 186   st->print(", CORE ");
 187   getrlimit(RLIMIT_CORE, &rlim);
 188   if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
 189   else st->print("%uk", rlim.rlim_cur >> 10);
 190 
 191   // Isn't there on solaris
 192 #if !defined(TARGET_OS_FAMILY_solaris) && !defined(TARGET_OS_FAMILY_aix)
 193   st->print(", NPROC ");
 194   getrlimit(RLIMIT_NPROC, &rlim);
 195   if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
 196   else st->print("%d", rlim.rlim_cur);
 197 #endif
 198 
 199   st->print(", NOFILE ");
 200   getrlimit(RLIMIT_NOFILE, &rlim);
 201   if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
 202   else st->print("%d", rlim.rlim_cur);
 203 
 204   st->print(", AS ");
 205   getrlimit(RLIMIT_AS, &rlim);
 206   if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
 207   else st->print("%uk", rlim.rlim_cur >> 10);
 208   st->cr();
 209 }
 210 
 211 void os::Posix::print_uname_info(outputStream* st) {
 212   // kernel
 213   st->print("uname:");
 214   struct utsname name;
 215   uname(&name);
 216   st->print("%s ", name.sysname);
 217   st->print("%s ", name.release);
 218   st->print("%s ", name.version);
 219   st->print("%s", name.machine);
 220   st->cr();
 221 }
 222 
 223 bool os::has_allocatable_memory_limit(julong* limit) {
 224   struct rlimit rlim;
 225   int getrlimit_res = getrlimit(RLIMIT_AS, &rlim);
 226   // if there was an error when calling getrlimit, assume that there is no limitation
 227   // on virtual memory.
 228   bool result;
 229   if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) {
 230     result = false;
 231   } else {
 232     *limit = (julong)rlim.rlim_cur;
 233     result = true;
 234   }
 235 #ifdef _LP64
 236   return result;
 237 #else
 238   // arbitrary virtual space limit for 32 bit Unices found by testing. If
 239   // getrlimit above returned a limit, bound it with this limit. Otherwise
 240   // directly use it.
 241   const julong max_virtual_limit = (julong)3800*M;
 242   if (result) {
 243     *limit = MIN2(*limit, max_virtual_limit);
 244   } else {
 245     *limit = max_virtual_limit;
 246   }
 247 
 248   // bound by actually allocatable memory. The algorithm uses two bounds, an
 249   // upper and a lower limit. The upper limit is the current highest amount of
 250   // memory that could not be allocated, the lower limit is the current highest
 251   // amount of memory that could be allocated.
 252   // The algorithm iteratively refines the result by halving the difference
 253   // between these limits, updating either the upper limit (if that value could
 254   // not be allocated) or the lower limit (if the that value could be allocated)
 255   // until the difference between these limits is "small".
 256 
 257   // the minimum amount of memory we care about allocating.
 258   const julong min_allocation_size = M;
 259 
 260   julong upper_limit = *limit;
 261 
 262   // first check a few trivial cases
 263   if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) {
 264     *limit = upper_limit;
 265   } else if (!is_allocatable(min_allocation_size)) {
 266     // we found that not even min_allocation_size is allocatable. Return it
 267     // anyway. There is no point to search for a better value any more.
 268     *limit = min_allocation_size;
 269   } else {
 270     // perform the binary search.
 271     julong lower_limit = min_allocation_size;
 272     while ((upper_limit - lower_limit) > min_allocation_size) {
 273       julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit;
 274       temp_limit = align_size_down_(temp_limit, min_allocation_size);
 275       if (is_allocatable(temp_limit)) {
 276         lower_limit = temp_limit;
 277       } else {
 278         upper_limit = temp_limit;
 279       }
 280     }
 281     *limit = lower_limit;
 282   }
 283   return true;
 284 #endif
 285 }
 286 
 287 const char* os::get_current_directory(char *buf, size_t buflen) {
 288   return getcwd(buf, buflen);
 289 }
 290 
 291 FILE* os::open(int fd, const char* mode) {
 292   return ::fdopen(fd, mode);
 293 }
 294 
 295 // Builds a platform dependent Agent_OnLoad_<lib_name> function name
 296 // which is used to find statically linked in agents.
 297 // Parameters:
 298 //            sym_name: Symbol in library we are looking for
 299 //            lib_name: Name of library to look in, NULL for shared libs.
 300 //            is_absolute_path == true if lib_name is absolute path to agent
 301 //                                     such as "/a/b/libL.so"
 302 //            == false if only the base name of the library is passed in
 303 //               such as "L"
 304 char* os::build_agent_function_name(const char *sym_name, const char *lib_name,
 305                                     bool is_absolute_path) {
 306   char *agent_entry_name;
 307   size_t len;
 308   size_t name_len;
 309   size_t prefix_len = strlen(JNI_LIB_PREFIX);
 310   size_t suffix_len = strlen(JNI_LIB_SUFFIX);
 311   const char *start;
 312 
 313   if (lib_name != NULL) {
 314     len = name_len = strlen(lib_name);
 315     if (is_absolute_path) {
 316       // Need to strip path, prefix and suffix
 317       if ((start = strrchr(lib_name, *os::file_separator())) != NULL) {
 318         lib_name = ++start;
 319       }
 320       if (len <= (prefix_len + suffix_len)) {
 321         return NULL;
 322       }
 323       lib_name += prefix_len;
 324       name_len = strlen(lib_name) - suffix_len;
 325     }
 326   }
 327   len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2;
 328   agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread);
 329   if (agent_entry_name == NULL) {
 330     return NULL;
 331   }
 332   strcpy(agent_entry_name, sym_name);
 333   if (lib_name != NULL) {
 334     strcat(agent_entry_name, "_");
 335     strncat(agent_entry_name, lib_name, name_len);
 336   }
 337   return agent_entry_name;
 338 }
 339 
 340 // Returned string is a constant. For unknown signals "UNKNOWN" is returned.
 341 const char* os::Posix::get_signal_name(int sig, char* out, size_t outlen) {
 342 
 343   static const struct {
 344     int sig; const char* name;
 345   }
 346   info[] =
 347   {
 348     {  SIGABRT,     "SIGABRT" },
 349 #ifdef SIGAIO
 350     {  SIGAIO,      "SIGAIO" },
 351 #endif
 352     {  SIGALRM,     "SIGALRM" },
 353 #ifdef SIGALRM1
 354     {  SIGALRM1,    "SIGALRM1" },
 355 #endif
 356     {  SIGBUS,      "SIGBUS" },
 357 #ifdef SIGCANCEL
 358     {  SIGCANCEL,   "SIGCANCEL" },
 359 #endif
 360     {  SIGCHLD,     "SIGCHLD" },
 361 #ifdef SIGCLD
 362     {  SIGCLD,      "SIGCLD" },
 363 #endif
 364     {  SIGCONT,     "SIGCONT" },
 365 #ifdef SIGCPUFAIL
 366     {  SIGCPUFAIL,  "SIGCPUFAIL" },
 367 #endif
 368 #ifdef SIGDANGER
 369     {  SIGDANGER,   "SIGDANGER" },
 370 #endif
 371 #ifdef SIGDIL
 372     {  SIGDIL,      "SIGDIL" },
 373 #endif
 374 #ifdef SIGEMT
 375     {  SIGEMT,      "SIGEMT" },
 376 #endif
 377     {  SIGFPE,      "SIGFPE" },
 378 #ifdef SIGFREEZE
 379     {  SIGFREEZE,   "SIGFREEZE" },
 380 #endif
 381 #ifdef SIGGFAULT
 382     {  SIGGFAULT,   "SIGGFAULT" },
 383 #endif
 384 #ifdef SIGGRANT
 385     {  SIGGRANT,    "SIGGRANT" },
 386 #endif
 387     {  SIGHUP,      "SIGHUP" },
 388     {  SIGILL,      "SIGILL" },
 389     {  SIGINT,      "SIGINT" },
 390 #ifdef SIGIO
 391     {  SIGIO,       "SIGIO" },
 392 #endif
 393 #ifdef SIGIOINT
 394     {  SIGIOINT,    "SIGIOINT" },
 395 #endif
 396 #ifdef SIGIOT
 397   // SIGIOT is there for BSD compatibility, but on most Unices just a
 398   // synonym for SIGABRT. The result should be "SIGABRT", not
 399   // "SIGIOT".
 400   #if (SIGIOT != SIGABRT )
 401     {  SIGIOT,      "SIGIOT" },
 402   #endif
 403 #endif
 404 #ifdef SIGKAP
 405     {  SIGKAP,      "SIGKAP" },
 406 #endif
 407     {  SIGKILL,     "SIGKILL" },
 408 #ifdef SIGLOST
 409     {  SIGLOST,     "SIGLOST" },
 410 #endif
 411 #ifdef SIGLWP
 412     {  SIGLWP,      "SIGLWP" },
 413 #endif
 414 #ifdef SIGLWPTIMER
 415     {  SIGLWPTIMER, "SIGLWPTIMER" },
 416 #endif
 417 #ifdef SIGMIGRATE
 418     {  SIGMIGRATE,  "SIGMIGRATE" },
 419 #endif
 420 #ifdef SIGMSG
 421     {  SIGMSG,      "SIGMSG" },
 422 #endif
 423     {  SIGPIPE,     "SIGPIPE" },
 424 #ifdef SIGPOLL
 425     {  SIGPOLL,     "SIGPOLL" },
 426 #endif
 427 #ifdef SIGPRE
 428     {  SIGPRE,      "SIGPRE" },
 429 #endif
 430     {  SIGPROF,     "SIGPROF" },
 431 #ifdef SIGPTY
 432     {  SIGPTY,      "SIGPTY" },
 433 #endif
 434 #ifdef SIGPWR
 435     {  SIGPWR,      "SIGPWR" },
 436 #endif
 437     {  SIGQUIT,     "SIGQUIT" },
 438 #ifdef SIGRECONFIG
 439     {  SIGRECONFIG, "SIGRECONFIG" },
 440 #endif
 441 #ifdef SIGRECOVERY
 442     {  SIGRECOVERY, "SIGRECOVERY" },
 443 #endif
 444 #ifdef SIGRESERVE
 445     {  SIGRESERVE,  "SIGRESERVE" },
 446 #endif
 447 #ifdef SIGRETRACT
 448     {  SIGRETRACT,  "SIGRETRACT" },
 449 #endif
 450 #ifdef SIGSAK
 451     {  SIGSAK,      "SIGSAK" },
 452 #endif
 453     {  SIGSEGV,     "SIGSEGV" },
 454 #ifdef SIGSOUND
 455     {  SIGSOUND,    "SIGSOUND" },
 456 #endif
 457     {  SIGSTOP,     "SIGSTOP" },
 458     {  SIGSYS,      "SIGSYS" },
 459 #ifdef SIGSYSERROR
 460     {  SIGSYSERROR, "SIGSYSERROR" },
 461 #endif
 462 #ifdef SIGTALRM
 463     {  SIGTALRM,    "SIGTALRM" },
 464 #endif
 465     {  SIGTERM,     "SIGTERM" },
 466 #ifdef SIGTHAW
 467     {  SIGTHAW,     "SIGTHAW" },
 468 #endif
 469     {  SIGTRAP,     "SIGTRAP" },
 470 #ifdef SIGTSTP
 471     {  SIGTSTP,     "SIGTSTP" },
 472 #endif
 473     {  SIGTTIN,     "SIGTTIN" },
 474     {  SIGTTOU,     "SIGTTOU" },
 475 #ifdef SIGURG
 476     {  SIGURG,      "SIGURG" },
 477 #endif
 478     {  SIGUSR1,     "SIGUSR1" },
 479     {  SIGUSR2,     "SIGUSR2" },
 480 #ifdef SIGVIRT
 481     {  SIGVIRT,     "SIGVIRT" },
 482 #endif
 483     {  SIGVTALRM,   "SIGVTALRM" },
 484 #ifdef SIGWAITING
 485     {  SIGWAITING,  "SIGWAITING" },
 486 #endif
 487 #ifdef SIGWINCH
 488     {  SIGWINCH,    "SIGWINCH" },
 489 #endif
 490 #ifdef SIGWINDOW
 491     {  SIGWINDOW,   "SIGWINDOW" },
 492 #endif
 493     {  SIGXCPU,     "SIGXCPU" },
 494     {  SIGXFSZ,     "SIGXFSZ" },
 495 #ifdef SIGXRES
 496     {  SIGXRES,     "SIGXRES" },
 497 #endif
 498     { -1, NULL }
 499   };
 500 
 501   const char* ret = NULL;
 502 
 503 #ifdef SIGRTMIN
 504   if (sig >= SIGRTMIN && sig <= SIGRTMAX) {
 505     if (sig == SIGRTMIN) {
 506       ret = "SIGRTMIN";
 507     } else if (sig == SIGRTMAX) {
 508       ret = "SIGRTMAX";
 509     } else {
 510       jio_snprintf(out, outlen, "SIGRTMIN+%d", sig - SIGRTMIN);
 511       return out;
 512     }
 513   }
 514 #endif
 515 
 516   if (sig > 0) {
 517     for (int idx = 0; info[idx].sig != -1; idx ++) {
 518       if (info[idx].sig == sig) {
 519         ret = info[idx].name;
 520         break;
 521       }
 522     }
 523   }
 524 
 525   if (!ret) {
 526     if (!is_valid_signal(sig)) {
 527       ret = "INVALID";
 528     } else {
 529       ret = "UNKNOWN";
 530     }
 531   }
 532 
 533   jio_snprintf(out, outlen, ret);
 534   return out;
 535 }
 536 
 537 // Returns true if signal number is valid.
 538 bool os::Posix::is_valid_signal(int sig) {
 539   // MacOS not really POSIX compliant: sigaddset does not return
 540   // an error for invalid signal numbers. However, MacOS does not
 541   // support real time signals and simply seems to have just 33
 542   // signals with no holes in the signal range.
 543 #ifdef __APPLE__
 544   return sig >= 1 && sig < NSIG;
 545 #else
 546   // Use sigaddset to check for signal validity.
 547   sigset_t set;
 548   if (sigaddset(&set, sig) == -1 && errno == EINVAL) {
 549     return false;
 550   }
 551   return true;
 552 #endif
 553 }
 554 
 555 #define NUM_IMPORTANT_SIGS 32
 556 // Returns one-line short description of a signal set in a user provided buffer.
 557 const char* os::Posix::describe_signal_set_short(const sigset_t* set, char* buffer, size_t buf_size) {
 558   assert(buf_size == (NUM_IMPORTANT_SIGS + 1), "wrong buffer size");
 559   // Note: for shortness, just print out the first 32. That should
 560   // cover most of the useful ones, apart from realtime signals.
 561   for (int sig = 1; sig <= NUM_IMPORTANT_SIGS; sig++) {
 562     const int rc = sigismember(set, sig);
 563     if (rc == -1 && errno == EINVAL) {
 564       buffer[sig-1] = '?';
 565     } else {
 566       buffer[sig-1] = rc == 0 ? '0' : '1';
 567     }
 568   }
 569   buffer[NUM_IMPORTANT_SIGS] = 0;
 570   return buffer;
 571 }
 572 
 573 // Prints one-line description of a signal set.
 574 void os::Posix::print_signal_set_short(outputStream* st, const sigset_t* set) {
 575   char buf[NUM_IMPORTANT_SIGS + 1];
 576   os::Posix::describe_signal_set_short(set, buf, sizeof(buf));
 577   st->print("%s", buf);
 578 }
 579 
 580 // Writes one-line description of a combination of sigaction.sa_flags into a user
 581 // provided buffer. Returns that buffer.
 582 const char* os::Posix::describe_sa_flags(int flags, char* buffer, size_t size) {
 583   char* p = buffer;
 584   size_t remaining = size;
 585   bool first = true;
 586   int idx = 0;
 587 
 588   assert(buffer, "invalid argument");
 589 
 590   if (size == 0) {
 591     return buffer;
 592   }
 593 
 594   strncpy(buffer, "none", size);
 595 
 596   const struct {
 597     int i;
 598     const char* s;
 599   } flaginfo [] = {
 600     { SA_NOCLDSTOP, "SA_NOCLDSTOP" },
 601     { SA_ONSTACK,   "SA_ONSTACK"   },
 602     { SA_RESETHAND, "SA_RESETHAND" },
 603     { SA_RESTART,   "SA_RESTART"   },
 604     { SA_SIGINFO,   "SA_SIGINFO"   },
 605     { SA_NOCLDWAIT, "SA_NOCLDWAIT" },
 606     { SA_NODEFER,   "SA_NODEFER"   },
 607 #ifdef AIX
 608     { SA_ONSTACK,   "SA_ONSTACK"   },
 609     { SA_OLDSTYLE,  "SA_OLDSTYLE"  },
 610 #endif
 611     { 0, NULL }
 612   };
 613 
 614   for (idx = 0; flaginfo[idx].s && remaining > 1; idx++) {
 615     if (flags & flaginfo[idx].i) {
 616       if (first) {
 617         jio_snprintf(p, remaining, "%s", flaginfo[idx].s);
 618         first = false;
 619       } else {
 620         jio_snprintf(p, remaining, "|%s", flaginfo[idx].s);
 621       }
 622       const size_t len = strlen(p);
 623       p += len;
 624       remaining -= len;
 625     }
 626   }
 627 
 628   buffer[size - 1] = '\0';
 629 
 630   return buffer;
 631 }
 632 
 633 // Prints one-line description of a combination of sigaction.sa_flags.
 634 void os::Posix::print_sa_flags(outputStream* st, int flags) {
 635   char buffer[0x100];
 636   os::Posix::describe_sa_flags(flags, buffer, sizeof(buffer));
 637   st->print("%s", buffer);
 638 }
 639 
 640 // Helper function for os::Posix::print_siginfo_...():
 641 // return a textual description for signal code.
 642 struct enum_sigcode_desc_t {
 643   const char* s_name;
 644   const char* s_desc;
 645 };
 646 
 647 static bool get_signal_code_description(const siginfo_t* si, enum_sigcode_desc_t* out) {
 648 
 649   const struct {
 650     int sig; int code; const char* s_code; const char* s_desc;
 651   } t1 [] = {
 652     { SIGILL,  ILL_ILLOPC,   "ILL_ILLOPC",   "Illegal opcode." },
 653     { SIGILL,  ILL_ILLOPN,   "ILL_ILLOPN",   "Illegal operand." },
 654     { SIGILL,  ILL_ILLADR,   "ILL_ILLADR",   "Illegal addressing mode." },
 655     { SIGILL,  ILL_ILLTRP,   "ILL_ILLTRP",   "Illegal trap." },
 656     { SIGILL,  ILL_PRVOPC,   "ILL_PRVOPC",   "Privileged opcode." },
 657     { SIGILL,  ILL_PRVREG,   "ILL_PRVREG",   "Privileged register." },
 658     { SIGILL,  ILL_COPROC,   "ILL_COPROC",   "Coprocessor error." },
 659     { SIGILL,  ILL_BADSTK,   "ILL_BADSTK",   "Internal stack error." },
 660 #if defined(IA64) && defined(LINUX)
 661     { SIGILL,  ILL_BADIADDR, "ILL_BADIADDR", "Unimplemented instruction address" },
 662     { SIGILL,  ILL_BREAK,    "ILL_BREAK",    "Application Break instruction" },
 663 #endif
 664     { SIGFPE,  FPE_INTDIV,   "FPE_INTDIV",   "Integer divide by zero." },
 665     { SIGFPE,  FPE_INTOVF,   "FPE_INTOVF",   "Integer overflow." },
 666     { SIGFPE,  FPE_FLTDIV,   "FPE_FLTDIV",   "Floating-point divide by zero." },
 667     { SIGFPE,  FPE_FLTOVF,   "FPE_FLTOVF",   "Floating-point overflow." },
 668     { SIGFPE,  FPE_FLTUND,   "FPE_FLTUND",   "Floating-point underflow." },
 669     { SIGFPE,  FPE_FLTRES,   "FPE_FLTRES",   "Floating-point inexact result." },
 670     { SIGFPE,  FPE_FLTINV,   "FPE_FLTINV",   "Invalid floating-point operation." },
 671     { SIGFPE,  FPE_FLTSUB,   "FPE_FLTSUB",   "Subscript out of range." },
 672     { SIGSEGV, SEGV_MAPERR,  "SEGV_MAPERR",  "Address not mapped to object." },
 673     { SIGSEGV, SEGV_ACCERR,  "SEGV_ACCERR",  "Invalid permissions for mapped object." },
 674 #ifdef AIX
 675     // no explanation found what keyerr would be
 676     { SIGSEGV, SEGV_KEYERR,  "SEGV_KEYERR",  "key error" },
 677 #endif
 678 #if defined(IA64) && !defined(AIX)
 679     { SIGSEGV, SEGV_PSTKOVF, "SEGV_PSTKOVF", "Paragraph stack overflow" },
 680 #endif
 681 #if defined(__sparc) && defined(SOLARIS)
 682 // define Solaris Sparc M7 ADI SEGV signals
 683 #if !defined(SEGV_ACCADI)
 684 #define SEGV_ACCADI 3
 685 #endif
 686     { SIGSEGV, SEGV_ACCADI,  "SEGV_ACCADI",  "ADI not enabled for mapped object." },
 687 #if !defined(SEGV_ACCDERR)
 688 #define SEGV_ACCDERR 4
 689 #endif
 690     { SIGSEGV, SEGV_ACCDERR, "SEGV_ACCDERR", "ADI disrupting exception." },
 691 #if !defined(SEGV_ACCPERR)
 692 #define SEGV_ACCPERR 5
 693 #endif
 694     { SIGSEGV, SEGV_ACCPERR, "SEGV_ACCPERR", "ADI precise exception." },
 695 #endif // defined(__sparc) && defined(SOLARIS)
 696     { SIGBUS,  BUS_ADRALN,   "BUS_ADRALN",   "Invalid address alignment." },
 697     { SIGBUS,  BUS_ADRERR,   "BUS_ADRERR",   "Nonexistent physical address." },
 698     { SIGBUS,  BUS_OBJERR,   "BUS_OBJERR",   "Object-specific hardware error." },
 699     { SIGTRAP, TRAP_BRKPT,   "TRAP_BRKPT",   "Process breakpoint." },
 700     { SIGTRAP, TRAP_TRACE,   "TRAP_TRACE",   "Process trace trap." },
 701     { SIGCHLD, CLD_EXITED,   "CLD_EXITED",   "Child has exited." },
 702     { SIGCHLD, CLD_KILLED,   "CLD_KILLED",   "Child has terminated abnormally and did not create a core file." },
 703     { SIGCHLD, CLD_DUMPED,   "CLD_DUMPED",   "Child has terminated abnormally and created a core file." },
 704     { SIGCHLD, CLD_TRAPPED,  "CLD_TRAPPED",  "Traced child has trapped." },
 705     { SIGCHLD, CLD_STOPPED,  "CLD_STOPPED",  "Child has stopped." },
 706     { SIGCHLD, CLD_CONTINUED,"CLD_CONTINUED","Stopped child has continued." },
 707 #ifdef SIGPOLL
 708     { SIGPOLL, POLL_OUT,     "POLL_OUT",     "Output buffers available." },
 709     { SIGPOLL, POLL_MSG,     "POLL_MSG",     "Input message available." },
 710     { SIGPOLL, POLL_ERR,     "POLL_ERR",     "I/O error." },
 711     { SIGPOLL, POLL_PRI,     "POLL_PRI",     "High priority input available." },
 712     { SIGPOLL, POLL_HUP,     "POLL_HUP",     "Device disconnected. [Option End]" },
 713 #endif
 714     { -1, -1, NULL, NULL }
 715   };
 716 
 717   // Codes valid in any signal context.
 718   const struct {
 719     int code; const char* s_code; const char* s_desc;
 720   } t2 [] = {
 721     { SI_USER,      "SI_USER",     "Signal sent by kill()." },
 722     { SI_QUEUE,     "SI_QUEUE",    "Signal sent by the sigqueue()." },
 723     { SI_TIMER,     "SI_TIMER",    "Signal generated by expiration of a timer set by timer_settime()." },
 724     { SI_ASYNCIO,   "SI_ASYNCIO",  "Signal generated by completion of an asynchronous I/O request." },
 725     { SI_MESGQ,     "SI_MESGQ",    "Signal generated by arrival of a message on an empty message queue." },
 726     // Linux specific
 727 #ifdef SI_TKILL
 728     { SI_TKILL,     "SI_TKILL",    "Signal sent by tkill (pthread_kill)" },
 729 #endif
 730 #ifdef SI_DETHREAD
 731     { SI_DETHREAD,  "SI_DETHREAD", "Signal sent by execve() killing subsidiary threads" },
 732 #endif
 733 #ifdef SI_KERNEL
 734     { SI_KERNEL,    "SI_KERNEL",   "Signal sent by kernel." },
 735 #endif
 736 #ifdef SI_SIGIO
 737     { SI_SIGIO,     "SI_SIGIO",    "Signal sent by queued SIGIO" },
 738 #endif
 739 
 740 #ifdef AIX
 741     { SI_UNDEFINED, "SI_UNDEFINED","siginfo contains partial information" },
 742     { SI_EMPTY,     "SI_EMPTY",    "siginfo contains no useful information" },
 743 #endif
 744 
 745 #ifdef __sun
 746     { SI_NOINFO,    "SI_NOINFO",   "No signal information" },
 747     { SI_RCTL,      "SI_RCTL",     "kernel generated signal via rctl action" },
 748     { SI_LWP,       "SI_LWP",      "Signal sent via lwp_kill" },
 749 #endif
 750 
 751     { -1, NULL, NULL }
 752   };
 753 
 754   const char* s_code = NULL;
 755   const char* s_desc = NULL;
 756 
 757   for (int i = 0; t1[i].sig != -1; i ++) {
 758     if (t1[i].sig == si->si_signo && t1[i].code == si->si_code) {
 759       s_code = t1[i].s_code;
 760       s_desc = t1[i].s_desc;
 761       break;
 762     }
 763   }
 764 
 765   if (s_code == NULL) {
 766     for (int i = 0; t2[i].s_code != NULL; i ++) {
 767       if (t2[i].code == si->si_code) {
 768         s_code = t2[i].s_code;
 769         s_desc = t2[i].s_desc;
 770       }
 771     }
 772   }
 773 
 774   if (s_code == NULL) {
 775     out->s_name = "unknown";
 776     out->s_desc = "unknown";
 777     return false;
 778   }
 779 
 780   out->s_name = s_code;
 781   out->s_desc = s_desc;
 782 
 783   return true;
 784 }
 785 
 786 // A POSIX conform, platform-independend siginfo print routine.
 787 // Short print out on one line.
 788 void os::Posix::print_siginfo_brief(outputStream* os, const siginfo_t* si) {
 789   char buf[20];
 790   os->print("siginfo: ");
 791 
 792   if (!si) {
 793     os->print("<null>");
 794     return;
 795   }
 796 
 797   // See print_siginfo_full() for details.
 798   const int sig = si->si_signo;
 799 
 800   os->print("si_signo: %d (%s)", sig, os::Posix::get_signal_name(sig, buf, sizeof(buf)));
 801 
 802   enum_sigcode_desc_t ed;
 803   if (get_signal_code_description(si, &ed)) {
 804     os->print(", si_code: %d (%s)", si->si_code, ed.s_name);
 805   } else {
 806     os->print(", si_code: %d (unknown)", si->si_code);
 807   }
 808 
 809   if (si->si_errno) {
 810     os->print(", si_errno: %d", si->si_errno);
 811   }
 812 
 813   const int me = (int) ::getpid();
 814   const int pid = (int) si->si_pid;
 815 
 816   if (si->si_code == SI_USER || si->si_code == SI_QUEUE) {
 817     if (IS_VALID_PID(pid) && pid != me) {
 818       os->print(", sent from pid: %d (uid: %d)", pid, (int) si->si_uid);
 819     }
 820   } else if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
 821              sig == SIGTRAP || sig == SIGFPE) {
 822     os->print(", si_addr: " PTR_FORMAT, si->si_addr);
 823 #ifdef SIGPOLL
 824   } else if (sig == SIGPOLL) {
 825     os->print(", si_band: " PTR64_FORMAT, (uint64_t)si->si_band);
 826 #endif
 827   } else if (sig == SIGCHLD) {
 828     os->print_cr(", si_pid: %d, si_uid: %d, si_status: %d", (int) si->si_pid, si->si_uid, si->si_status);
 829   }
 830 }
 831 
 832 os::WatcherThreadCrashProtection::WatcherThreadCrashProtection() {
 833   assert(Thread::current()->is_Watcher_thread(), "Must be WatcherThread");
 834 }
 835 
 836 /*
 837  * See the caveats for this class in os_posix.hpp
 838  * Protects the callback call so that SIGSEGV / SIGBUS jumps back into this
 839  * method and returns false. If none of the signals are raised, returns true.
 840  * The callback is supposed to provide the method that should be protected.
 841  */
 842 bool os::WatcherThreadCrashProtection::call(os::CrashProtectionCallback& cb) {
 843   sigset_t saved_sig_mask;
 844 
 845   assert(Thread::current()->is_Watcher_thread(), "Only for WatcherThread");
 846   assert(!WatcherThread::watcher_thread()->has_crash_protection(),
 847       "crash_protection already set?");
 848 
 849   // we cannot rely on sigsetjmp/siglongjmp to save/restore the signal mask
 850   // since on at least some systems (OS X) siglongjmp will restore the mask
 851   // for the process, not the thread
 852   pthread_sigmask(0, NULL, &saved_sig_mask);
 853   if (sigsetjmp(_jmpbuf, 0) == 0) {
 854     // make sure we can see in the signal handler that we have crash protection
 855     // installed
 856     WatcherThread::watcher_thread()->set_crash_protection(this);
 857     cb.call();
 858     // and clear the crash protection
 859     WatcherThread::watcher_thread()->set_crash_protection(NULL);
 860     return true;
 861   }
 862   // this happens when we siglongjmp() back
 863   pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL);
 864   WatcherThread::watcher_thread()->set_crash_protection(NULL);
 865   return false;
 866 }
 867 
 868 void os::WatcherThreadCrashProtection::restore() {
 869   assert(WatcherThread::watcher_thread()->has_crash_protection(),
 870       "must have crash protection");
 871 
 872   siglongjmp(_jmpbuf, 1);
 873 }
 874 
 875 void os::WatcherThreadCrashProtection::check_crash_protection(int sig,
 876     Thread* thread) {
 877 
 878   if (thread != NULL &&
 879       thread->is_Watcher_thread() &&
 880       WatcherThread::watcher_thread()->has_crash_protection()) {
 881 
 882     if (sig == SIGSEGV || sig == SIGBUS) {
 883       WatcherThread::watcher_thread()->crash_protection()->restore();
 884     }
 885   }
 886 }