1 /*
   2  * Copyright (c) 1999, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2012, 2017 SAP SE. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 // According to the AIX OS doc #pragma alloca must be used
  27 // with C++ compiler before referencing the function alloca()
  28 #pragma alloca
  29 
  30 // no precompiled headers
  31 #include "jvm.h"
  32 #include "classfile/classLoader.hpp"
  33 #include "classfile/systemDictionary.hpp"
  34 #include "classfile/vmSymbols.hpp"
  35 #include "code/icBuffer.hpp"
  36 #include "code/vtableStubs.hpp"
  37 #include "compiler/compileBroker.hpp"
  38 #include "interpreter/interpreter.hpp"
  39 #include "logging/log.hpp"
  40 #include "libo4.hpp"
  41 #include "libperfstat_aix.hpp"
  42 #include "libodm_aix.hpp"
  43 #include "loadlib_aix.hpp"
  44 #include "memory/allocation.inline.hpp"
  45 #include "memory/filemap.hpp"
  46 #include "misc_aix.hpp"
  47 #include "oops/oop.inline.hpp"
  48 #include "os_aix.inline.hpp"
  49 #include "os_share_aix.hpp"
  50 #include "porting_aix.hpp"
  51 #include "prims/jniFastGetField.hpp"
  52 #include "prims/jvm_misc.hpp"
  53 #include "runtime/arguments.hpp"
  54 #include "runtime/atomic.hpp"
  55 #include "runtime/extendedPC.hpp"
  56 #include "runtime/globals.hpp"
  57 #include "runtime/interfaceSupport.hpp"
  58 #include "runtime/java.hpp"
  59 #include "runtime/javaCalls.hpp"
  60 #include "runtime/mutexLocker.hpp"
  61 #include "runtime/objectMonitor.hpp"
  62 #include "runtime/orderAccess.inline.hpp"
  63 #include "runtime/os.hpp"
  64 #include "runtime/osThread.hpp"
  65 #include "runtime/perfMemory.hpp"
  66 #include "runtime/sharedRuntime.hpp"
  67 #include "runtime/statSampler.hpp"
  68 #include "runtime/stubRoutines.hpp"
  69 #include "runtime/thread.inline.hpp"
  70 #include "runtime/threadCritical.hpp"
  71 #include "runtime/timer.hpp"
  72 #include "runtime/vm_version.hpp"
  73 #include "services/attachListener.hpp"
  74 #include "services/runtimeService.hpp"
  75 #include "utilities/align.hpp"
  76 #include "utilities/decoder.hpp"
  77 #include "utilities/defaultStream.hpp"
  78 #include "utilities/events.hpp"
  79 #include "utilities/growableArray.hpp"
  80 #include "utilities/vmError.hpp"
  81 
  82 // put OS-includes here (sorted alphabetically)
  83 #include <errno.h>
  84 #include <fcntl.h>
  85 #include <inttypes.h>
  86 #include <poll.h>
  87 #include <procinfo.h>
  88 #include <pthread.h>
  89 #include <pwd.h>
  90 #include <semaphore.h>
  91 #include <signal.h>
  92 #include <stdint.h>
  93 #include <stdio.h>
  94 #include <string.h>
  95 #include <unistd.h>
  96 #include <sys/ioctl.h>
  97 #include <sys/ipc.h>
  98 #include <sys/mman.h>
  99 #include <sys/resource.h>
 100 #include <sys/select.h>
 101 #include <sys/shm.h>
 102 #include <sys/socket.h>
 103 #include <sys/stat.h>
 104 #include <sys/sysinfo.h>
 105 #include <sys/systemcfg.h>
 106 #include <sys/time.h>
 107 #include <sys/times.h>
 108 #include <sys/types.h>
 109 #include <sys/utsname.h>
 110 #include <sys/vminfo.h>
 111 #include <sys/wait.h>
 112 
 113 // Missing prototypes for various system APIs.
 114 extern "C"
 115 int mread_real_time(timebasestruct_t *t, size_t size_of_timebasestruct_t);
 116 
 117 #if !defined(_AIXVERSION_610)
 118 extern "C" int getthrds64(pid_t, struct thrdentry64*, int, tid64_t*, int);
 119 extern "C" int getprocs64(procentry64*, int, fdsinfo*, int, pid_t*, int);
 120 extern "C" int getargs   (procsinfo*, int, char*, int);
 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 // for multipage initialization error analysis (in 'g_multipage_error')
 128 #define ERROR_MP_OS_TOO_OLD                          100
 129 #define ERROR_MP_EXTSHM_ACTIVE                       101
 130 #define ERROR_MP_VMGETINFO_FAILED                    102
 131 #define ERROR_MP_VMGETINFO_CLAIMS_NO_SUPPORT_FOR_64K 103
 132 
 133 static address resolve_function_descriptor_to_code_pointer(address p);
 134 
 135 static void vmembk_print_on(outputStream* os);
 136 
 137 ////////////////////////////////////////////////////////////////////////////////
 138 // global variables (for a description see os_aix.hpp)
 139 
 140 julong    os::Aix::_physical_memory = 0;
 141 
 142 pthread_t os::Aix::_main_thread = ((pthread_t)0);
 143 int       os::Aix::_page_size = -1;
 144 
 145 // -1 = uninitialized, 0 if AIX, 1 if OS/400 pase
 146 int       os::Aix::_on_pase = -1;
 147 
 148 // 0 = uninitialized, otherwise 32 bit number:
 149 //  0xVVRRTTSS
 150 //  VV - major version
 151 //  RR - minor version
 152 //  TT - tech level, if known, 0 otherwise
 153 //  SS - service pack, if known, 0 otherwise
 154 uint32_t  os::Aix::_os_version = 0;
 155 
 156 // -1 = uninitialized, 0 - no, 1 - yes
 157 int       os::Aix::_xpg_sus_mode = -1;
 158 
 159 // -1 = uninitialized, 0 - no, 1 - yes
 160 int       os::Aix::_extshm = -1;
 161 
 162 ////////////////////////////////////////////////////////////////////////////////
 163 // local variables
 164 
 165 static jlong    initial_time_count = 0;
 166 static int      clock_tics_per_sec = 100;
 167 static sigset_t check_signal_done;         // For diagnostics to print a message once (see run_periodic_checks)
 168 static bool     check_signals      = true;
 169 static int      SR_signum          = SIGUSR2; // Signal used to suspend/resume a thread (must be > SIGSEGV, see 4355769)
 170 static sigset_t SR_sigset;
 171 
 172 // Process break recorded at startup.
 173 static address g_brk_at_startup = NULL;
 174 
 175 // This describes the state of multipage support of the underlying
 176 // OS. Note that this is of no interest to the outsize world and
 177 // therefore should not be defined in AIX class.
 178 //
 179 // AIX supports four different page sizes - 4K, 64K, 16MB, 16GB. The
 180 // latter two (16M "large" resp. 16G "huge" pages) require special
 181 // setup and are normally not available.
 182 //
 183 // AIX supports multiple page sizes per process, for:
 184 //  - Stack (of the primordial thread, so not relevant for us)
 185 //  - Data - data, bss, heap, for us also pthread stacks
 186 //  - Text - text code
 187 //  - shared memory
 188 //
 189 // Default page sizes can be set via linker options (-bdatapsize, -bstacksize, ...)
 190 // and via environment variable LDR_CNTRL (DATAPSIZE, STACKPSIZE, ...).
 191 //
 192 // For shared memory, page size can be set dynamically via
 193 // shmctl(). Different shared memory regions can have different page
 194 // sizes.
 195 //
 196 // More information can be found at AIBM info center:
 197 //   http://publib.boulder.ibm.com/infocenter/aix/v6r1/index.jsp?topic=/com.ibm.aix.prftungd/doc/prftungd/multiple_page_size_app_support.htm
 198 //
 199 static struct {
 200   size_t pagesize;            // sysconf _SC_PAGESIZE (4K)
 201   size_t datapsize;           // default data page size (LDR_CNTRL DATAPSIZE)
 202   size_t shmpsize;            // default shared memory page size (LDR_CNTRL SHMPSIZE)
 203   size_t pthr_stack_pagesize; // stack page size of pthread threads
 204   size_t textpsize;           // default text page size (LDR_CNTRL STACKPSIZE)
 205   bool can_use_64K_pages;     // True if we can alloc 64K pages dynamically with Sys V shm.
 206   bool can_use_16M_pages;     // True if we can alloc 16M pages dynamically with Sys V shm.
 207   int error;                  // Error describing if something went wrong at multipage init.
 208 } g_multipage_support = {
 209   (size_t) -1,
 210   (size_t) -1,
 211   (size_t) -1,
 212   (size_t) -1,
 213   (size_t) -1,
 214   false, false,
 215   0
 216 };
 217 
 218 // We must not accidentally allocate memory close to the BRK - even if
 219 // that would work - because then we prevent the BRK segment from
 220 // growing which may result in a malloc OOM even though there is
 221 // enough memory. The problem only arises if we shmat() or mmap() at
 222 // a specific wish address, e.g. to place the heap in a
 223 // compressed-oops-friendly way.
 224 static bool is_close_to_brk(address a) {
 225   assert0(g_brk_at_startup != NULL);
 226   if (a >= g_brk_at_startup &&
 227       a < (g_brk_at_startup + MaxExpectedDataSegmentSize)) {
 228     return true;
 229   }
 230   return false;
 231 }
 232 
 233 julong os::available_memory() {
 234   return Aix::available_memory();
 235 }
 236 
 237 julong os::Aix::available_memory() {
 238   // Avoid expensive API call here, as returned value will always be null.
 239   if (os::Aix::on_pase()) {
 240     return 0x0LL;
 241   }
 242   os::Aix::meminfo_t mi;
 243   if (os::Aix::get_meminfo(&mi)) {
 244     return mi.real_free;
 245   } else {
 246     return ULONG_MAX;
 247   }
 248 }
 249 
 250 julong os::physical_memory() {
 251   return Aix::physical_memory();
 252 }
 253 
 254 // Return true if user is running as root.
 255 
 256 bool os::have_special_privileges() {
 257   static bool init = false;
 258   static bool privileges = false;
 259   if (!init) {
 260     privileges = (getuid() != geteuid()) || (getgid() != getegid());
 261     init = true;
 262   }
 263   return privileges;
 264 }
 265 
 266 // Helper function, emulates disclaim64 using multiple 32bit disclaims
 267 // because we cannot use disclaim64() on AS/400 and old AIX releases.
 268 static bool my_disclaim64(char* addr, size_t size) {
 269 
 270   if (size == 0) {
 271     return true;
 272   }
 273 
 274   // Maximum size 32bit disclaim() accepts. (Theoretically 4GB, but I just do not trust that.)
 275   const unsigned int maxDisclaimSize = 0x40000000;
 276 
 277   const unsigned int numFullDisclaimsNeeded = (size / maxDisclaimSize);
 278   const unsigned int lastDisclaimSize = (size % maxDisclaimSize);
 279 
 280   char* p = addr;
 281 
 282   for (int i = 0; i < numFullDisclaimsNeeded; i ++) {
 283     if (::disclaim(p, maxDisclaimSize, DISCLAIM_ZEROMEM) != 0) {
 284       trcVerbose("Cannot disclaim %p - %p (errno %d)\n", p, p + maxDisclaimSize, errno);
 285       return false;
 286     }
 287     p += maxDisclaimSize;
 288   }
 289 
 290   if (lastDisclaimSize > 0) {
 291     if (::disclaim(p, lastDisclaimSize, DISCLAIM_ZEROMEM) != 0) {
 292       trcVerbose("Cannot disclaim %p - %p (errno %d)\n", p, p + lastDisclaimSize, errno);
 293       return false;
 294     }
 295   }
 296 
 297   return true;
 298 }
 299 
 300 // Cpu architecture string
 301 #if defined(PPC32)
 302 static char cpu_arch[] = "ppc";
 303 #elif defined(PPC64)
 304 static char cpu_arch[] = "ppc64";
 305 #else
 306 #error Add appropriate cpu_arch setting
 307 #endif
 308 
 309 // Wrap the function "vmgetinfo" which is not available on older OS releases.
 310 static int checked_vmgetinfo(void *out, int command, int arg) {
 311   if (os::Aix::on_pase() && os::Aix::os_version_short() < 0x0601) {
 312     guarantee(false, "cannot call vmgetinfo on AS/400 older than V6R1");
 313   }
 314   return ::vmgetinfo(out, command, arg);
 315 }
 316 
 317 // Given an address, returns the size of the page backing that address.
 318 size_t os::Aix::query_pagesize(void* addr) {
 319 
 320   if (os::Aix::on_pase() && os::Aix::os_version_short() < 0x0601) {
 321     // AS/400 older than V6R1: no vmgetinfo here, default to 4K
 322     return 4*K;
 323   }
 324 
 325   vm_page_info pi;
 326   pi.addr = (uint64_t)addr;
 327   if (checked_vmgetinfo(&pi, VM_PAGE_INFO, sizeof(pi)) == 0) {
 328     return pi.pagesize;
 329   } else {
 330     assert(false, "vmgetinfo failed to retrieve page size");
 331     return 4*K;
 332   }
 333 }
 334 
 335 void os::Aix::initialize_system_info() {
 336 
 337   // Get the number of online(logical) cpus instead of configured.
 338   os::_processor_count = sysconf(_SC_NPROCESSORS_ONLN);
 339   assert(_processor_count > 0, "_processor_count must be > 0");
 340 
 341   // Retrieve total physical storage.
 342   os::Aix::meminfo_t mi;
 343   if (!os::Aix::get_meminfo(&mi)) {
 344     assert(false, "os::Aix::get_meminfo failed.");
 345   }
 346   _physical_memory = (julong) mi.real_total;
 347 }
 348 
 349 // Helper function for tracing page sizes.
 350 static const char* describe_pagesize(size_t pagesize) {
 351   switch (pagesize) {
 352     case 4*K : return "4K";
 353     case 64*K: return "64K";
 354     case 16*M: return "16M";
 355     case 16*G: return "16G";
 356     default:
 357       assert(false, "surprise");
 358       return "??";
 359   }
 360 }
 361 
 362 // Probe OS for multipage support.
 363 // Will fill the global g_multipage_support structure.
 364 // Must be called before calling os::large_page_init().
 365 static void query_multipage_support() {
 366 
 367   guarantee(g_multipage_support.pagesize == -1,
 368             "do not call twice");
 369 
 370   g_multipage_support.pagesize = ::sysconf(_SC_PAGESIZE);
 371 
 372   // This really would surprise me.
 373   assert(g_multipage_support.pagesize == 4*K, "surprise!");
 374 
 375   // Query default data page size (default page size for C-Heap, pthread stacks and .bss).
 376   // Default data page size is defined either by linker options (-bdatapsize)
 377   // or by environment variable LDR_CNTRL (suboption DATAPSIZE). If none is given,
 378   // default should be 4K.
 379   {
 380     void* p = ::malloc(16*M);
 381     g_multipage_support.datapsize = os::Aix::query_pagesize(p);
 382     ::free(p);
 383   }
 384 
 385   // Query default shm page size (LDR_CNTRL SHMPSIZE).
 386   // Note that this is pure curiosity. We do not rely on default page size but set
 387   // our own page size after allocated.
 388   {
 389     const int shmid = ::shmget(IPC_PRIVATE, 1, IPC_CREAT | S_IRUSR | S_IWUSR);
 390     guarantee(shmid != -1, "shmget failed");
 391     void* p = ::shmat(shmid, NULL, 0);
 392     ::shmctl(shmid, IPC_RMID, NULL);
 393     guarantee(p != (void*) -1, "shmat failed");
 394     g_multipage_support.shmpsize = os::Aix::query_pagesize(p);
 395     ::shmdt(p);
 396   }
 397 
 398   // Before querying the stack page size, make sure we are not running as primordial
 399   // thread (because primordial thread's stack may have different page size than
 400   // pthread thread stacks). Running a VM on the primordial thread won't work for a
 401   // number of reasons so we may just as well guarantee it here.
 402   guarantee0(!os::Aix::is_primordial_thread());
 403 
 404   // Query pthread stack page size. Should be the same as data page size because
 405   // pthread stacks are allocated from C-Heap.
 406   {
 407     int dummy = 0;
 408     g_multipage_support.pthr_stack_pagesize = os::Aix::query_pagesize(&dummy);
 409   }
 410 
 411   // Query default text page size (LDR_CNTRL TEXTPSIZE).
 412   {
 413     address any_function =
 414       resolve_function_descriptor_to_code_pointer((address)describe_pagesize);
 415     g_multipage_support.textpsize = os::Aix::query_pagesize(any_function);
 416   }
 417 
 418   // Now probe for support of 64K pages and 16M pages.
 419 
 420   // Before OS/400 V6R1, there is no support for pages other than 4K.
 421   if (os::Aix::on_pase_V5R4_or_older()) {
 422     trcVerbose("OS/400 < V6R1 - no large page support.");
 423     g_multipage_support.error = ERROR_MP_OS_TOO_OLD;
 424     goto query_multipage_support_end;
 425   }
 426 
 427   // Now check which page sizes the OS claims it supports, and of those, which actually can be used.
 428   {
 429     const int MAX_PAGE_SIZES = 4;
 430     psize_t sizes[MAX_PAGE_SIZES];
 431     const int num_psizes = checked_vmgetinfo(sizes, VMINFO_GETPSIZES, MAX_PAGE_SIZES);
 432     if (num_psizes == -1) {
 433       trcVerbose("vmgetinfo(VMINFO_GETPSIZES) failed (errno: %d)", errno);
 434       trcVerbose("disabling multipage support.");
 435       g_multipage_support.error = ERROR_MP_VMGETINFO_FAILED;
 436       goto query_multipage_support_end;
 437     }
 438     guarantee(num_psizes > 0, "vmgetinfo(.., VMINFO_GETPSIZES, ...) failed.");
 439     assert(num_psizes <= MAX_PAGE_SIZES, "Surprise! more than 4 page sizes?");
 440     trcVerbose("vmgetinfo(.., VMINFO_GETPSIZES, ...) returns %d supported page sizes: ", num_psizes);
 441     for (int i = 0; i < num_psizes; i ++) {
 442       trcVerbose(" %s ", describe_pagesize(sizes[i]));
 443     }
 444 
 445     // Can we use 64K, 16M pages?
 446     for (int i = 0; i < num_psizes; i ++) {
 447       const size_t pagesize = sizes[i];
 448       if (pagesize != 64*K && pagesize != 16*M) {
 449         continue;
 450       }
 451       bool can_use = false;
 452       trcVerbose("Probing support for %s pages...", describe_pagesize(pagesize));
 453       const int shmid = ::shmget(IPC_PRIVATE, pagesize,
 454         IPC_CREAT | S_IRUSR | S_IWUSR);
 455       guarantee0(shmid != -1); // Should always work.
 456       // Try to set pagesize.
 457       struct shmid_ds shm_buf = { 0 };
 458       shm_buf.shm_pagesize = pagesize;
 459       if (::shmctl(shmid, SHM_PAGESIZE, &shm_buf) != 0) {
 460         const int en = errno;
 461         ::shmctl(shmid, IPC_RMID, NULL); // As early as possible!
 462         trcVerbose("shmctl(SHM_PAGESIZE) failed with errno=%n",
 463           errno);
 464       } else {
 465         // Attach and double check pageisze.
 466         void* p = ::shmat(shmid, NULL, 0);
 467         ::shmctl(shmid, IPC_RMID, NULL); // As early as possible!
 468         guarantee0(p != (void*) -1); // Should always work.
 469         const size_t real_pagesize = os::Aix::query_pagesize(p);
 470         if (real_pagesize != pagesize) {
 471           trcVerbose("real page size (0x%llX) differs.", real_pagesize);
 472         } else {
 473           can_use = true;
 474         }
 475         ::shmdt(p);
 476       }
 477       trcVerbose("Can use: %s", (can_use ? "yes" : "no"));
 478       if (pagesize == 64*K) {
 479         g_multipage_support.can_use_64K_pages = can_use;
 480       } else if (pagesize == 16*M) {
 481         g_multipage_support.can_use_16M_pages = can_use;
 482       }
 483     }
 484 
 485   } // end: check which pages can be used for shared memory
 486 
 487 query_multipage_support_end:
 488 
 489   trcVerbose("base page size (sysconf _SC_PAGESIZE): %s",
 490       describe_pagesize(g_multipage_support.pagesize));
 491   trcVerbose("Data page size (C-Heap, bss, etc): %s",
 492       describe_pagesize(g_multipage_support.datapsize));
 493   trcVerbose("Text page size: %s",
 494       describe_pagesize(g_multipage_support.textpsize));
 495   trcVerbose("Thread stack page size (pthread): %s",
 496       describe_pagesize(g_multipage_support.pthr_stack_pagesize));
 497   trcVerbose("Default shared memory page size: %s",
 498       describe_pagesize(g_multipage_support.shmpsize));
 499   trcVerbose("Can use 64K pages dynamically with shared meory: %s",
 500       (g_multipage_support.can_use_64K_pages ? "yes" :"no"));
 501   trcVerbose("Can use 16M pages dynamically with shared memory: %s",
 502       (g_multipage_support.can_use_16M_pages ? "yes" :"no"));
 503   trcVerbose("Multipage error details: %d",
 504       g_multipage_support.error);
 505 
 506   // sanity checks
 507   assert0(g_multipage_support.pagesize == 4*K);
 508   assert0(g_multipage_support.datapsize == 4*K || g_multipage_support.datapsize == 64*K);
 509   assert0(g_multipage_support.textpsize == 4*K || g_multipage_support.textpsize == 64*K);
 510   assert0(g_multipage_support.pthr_stack_pagesize == g_multipage_support.datapsize);
 511   assert0(g_multipage_support.shmpsize == 4*K || g_multipage_support.shmpsize == 64*K);
 512 
 513 }
 514 
 515 void os::init_system_properties_values() {
 516 
 517 #define DEFAULT_LIBPATH "/lib:/usr/lib"
 518 #define EXTENSIONS_DIR  "/lib/ext"
 519 
 520   // Buffer that fits several sprintfs.
 521   // Note that the space for the trailing null is provided
 522   // by the nulls included by the sizeof operator.
 523   const size_t bufsize =
 524     MAX2((size_t)MAXPATHLEN,  // For dll_dir & friends.
 525          (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR)); // extensions dir
 526   char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
 527 
 528   // sysclasspath, java_home, dll_dir
 529   {
 530     char *pslash;
 531     os::jvm_path(buf, bufsize);
 532 
 533     // Found the full path to libjvm.so.
 534     // Now cut the path to <java_home>/jre if we can.
 535     pslash = strrchr(buf, '/');
 536     if (pslash != NULL) {
 537       *pslash = '\0';            // Get rid of /libjvm.so.
 538     }
 539     pslash = strrchr(buf, '/');
 540     if (pslash != NULL) {
 541       *pslash = '\0';            // Get rid of /{client|server|hotspot}.
 542     }
 543     Arguments::set_dll_dir(buf);
 544 
 545     if (pslash != NULL) {
 546       pslash = strrchr(buf, '/');
 547       if (pslash != NULL) {
 548         *pslash = '\0';        // Get rid of /lib.
 549       }
 550     }
 551     Arguments::set_java_home(buf);
 552     set_boot_path('/', ':');
 553   }
 554 
 555   // Where to look for native libraries.
 556 
 557   // On Aix we get the user setting of LIBPATH.
 558   // Eventually, all the library path setting will be done here.
 559   // Get the user setting of LIBPATH.
 560   const char *v = ::getenv("LIBPATH");
 561   const char *v_colon = ":";
 562   if (v == NULL) { v = ""; v_colon = ""; }
 563 
 564   // Concatenate user and invariant part of ld_library_path.
 565   // That's +1 for the colon and +1 for the trailing '\0'.
 566   char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, strlen(v) + 1 + sizeof(DEFAULT_LIBPATH) + 1, mtInternal);
 567   sprintf(ld_library_path, "%s%s" DEFAULT_LIBPATH, v, v_colon);
 568   Arguments::set_library_path(ld_library_path);
 569   FREE_C_HEAP_ARRAY(char, ld_library_path);
 570 
 571   // Extensions directories.
 572   sprintf(buf, "%s" EXTENSIONS_DIR, Arguments::get_java_home());
 573   Arguments::set_ext_dirs(buf);
 574 
 575   FREE_C_HEAP_ARRAY(char, buf);
 576 
 577 #undef DEFAULT_LIBPATH
 578 #undef EXTENSIONS_DIR
 579 }
 580 
 581 ////////////////////////////////////////////////////////////////////////////////
 582 // breakpoint support
 583 
 584 void os::breakpoint() {
 585   BREAKPOINT;
 586 }
 587 
 588 extern "C" void breakpoint() {
 589   // use debugger to set breakpoint here
 590 }
 591 
 592 ////////////////////////////////////////////////////////////////////////////////
 593 // signal support
 594 
 595 debug_only(static bool signal_sets_initialized = false);
 596 static sigset_t unblocked_sigs, vm_sigs;
 597 
 598 bool os::Aix::is_sig_ignored(int sig) {
 599   struct sigaction oact;
 600   sigaction(sig, (struct sigaction*)NULL, &oact);
 601   void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
 602     : CAST_FROM_FN_PTR(void*, oact.sa_handler);
 603   if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) {
 604     return true;
 605   } else {
 606     return false;
 607   }
 608 }
 609 
 610 void os::Aix::signal_sets_init() {
 611   // Should also have an assertion stating we are still single-threaded.
 612   assert(!signal_sets_initialized, "Already initialized");
 613   // Fill in signals that are necessarily unblocked for all threads in
 614   // the VM. Currently, we unblock the following signals:
 615   // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
 616   //                         by -Xrs (=ReduceSignalUsage));
 617   // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
 618   // other threads. The "ReduceSignalUsage" boolean tells us not to alter
 619   // the dispositions or masks wrt these signals.
 620   // Programs embedding the VM that want to use the above signals for their
 621   // own purposes must, at this time, use the "-Xrs" option to prevent
 622   // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
 623   // (See bug 4345157, and other related bugs).
 624   // In reality, though, unblocking these signals is really a nop, since
 625   // these signals are not blocked by default.
 626   sigemptyset(&unblocked_sigs);
 627   sigaddset(&unblocked_sigs, SIGILL);
 628   sigaddset(&unblocked_sigs, SIGSEGV);
 629   sigaddset(&unblocked_sigs, SIGBUS);
 630   sigaddset(&unblocked_sigs, SIGFPE);
 631   sigaddset(&unblocked_sigs, SIGTRAP);
 632   sigaddset(&unblocked_sigs, SR_signum);
 633 
 634   if (!ReduceSignalUsage) {
 635    if (!os::Aix::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
 636      sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
 637    }
 638    if (!os::Aix::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
 639      sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
 640    }
 641    if (!os::Aix::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
 642      sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
 643    }
 644   }
 645   // Fill in signals that are blocked by all but the VM thread.
 646   sigemptyset(&vm_sigs);
 647   if (!ReduceSignalUsage)
 648     sigaddset(&vm_sigs, BREAK_SIGNAL);
 649   debug_only(signal_sets_initialized = true);
 650 }
 651 
 652 // These are signals that are unblocked while a thread is running Java.
 653 // (For some reason, they get blocked by default.)
 654 sigset_t* os::Aix::unblocked_signals() {
 655   assert(signal_sets_initialized, "Not initialized");
 656   return &unblocked_sigs;
 657 }
 658 
 659 // These are the signals that are blocked while a (non-VM) thread is
 660 // running Java. Only the VM thread handles these signals.
 661 sigset_t* os::Aix::vm_signals() {
 662   assert(signal_sets_initialized, "Not initialized");
 663   return &vm_sigs;
 664 }
 665 
 666 void os::Aix::hotspot_sigmask(Thread* thread) {
 667 
 668   //Save caller's signal mask before setting VM signal mask
 669   sigset_t caller_sigmask;
 670   pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
 671 
 672   OSThread* osthread = thread->osthread();
 673   osthread->set_caller_sigmask(caller_sigmask);
 674 
 675   pthread_sigmask(SIG_UNBLOCK, os::Aix::unblocked_signals(), NULL);
 676 
 677   if (!ReduceSignalUsage) {
 678     if (thread->is_VM_thread()) {
 679       // Only the VM thread handles BREAK_SIGNAL ...
 680       pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
 681     } else {
 682       // ... all other threads block BREAK_SIGNAL
 683       pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
 684     }
 685   }
 686 }
 687 
 688 // retrieve memory information.
 689 // Returns false if something went wrong;
 690 // content of pmi undefined in this case.
 691 bool os::Aix::get_meminfo(meminfo_t* pmi) {
 692 
 693   assert(pmi, "get_meminfo: invalid parameter");
 694 
 695   memset(pmi, 0, sizeof(meminfo_t));
 696 
 697   if (os::Aix::on_pase()) {
 698     // On PASE, use the libo4 porting library.
 699 
 700     unsigned long long virt_total = 0;
 701     unsigned long long real_total = 0;
 702     unsigned long long real_free = 0;
 703     unsigned long long pgsp_total = 0;
 704     unsigned long long pgsp_free = 0;
 705     if (libo4::get_memory_info(&virt_total, &real_total, &real_free, &pgsp_total, &pgsp_free)) {
 706       pmi->virt_total = virt_total;
 707       pmi->real_total = real_total;
 708       pmi->real_free = real_free;
 709       pmi->pgsp_total = pgsp_total;
 710       pmi->pgsp_free = pgsp_free;
 711       return true;
 712     }
 713     return false;
 714 
 715   } else {
 716 
 717     // On AIX, I use the (dynamically loaded) perfstat library to retrieve memory statistics
 718     // See:
 719     // http://publib.boulder.ibm.com/infocenter/systems/index.jsp
 720     //        ?topic=/com.ibm.aix.basetechref/doc/basetrf1/perfstat_memtot.htm
 721     // http://publib.boulder.ibm.com/infocenter/systems/index.jsp
 722     //        ?topic=/com.ibm.aix.files/doc/aixfiles/libperfstat.h.htm
 723 
 724     perfstat_memory_total_t psmt;
 725     memset (&psmt, '\0', sizeof(psmt));
 726     const int rc = libperfstat::perfstat_memory_total(NULL, &psmt, sizeof(psmt), 1);
 727     if (rc == -1) {
 728       trcVerbose("perfstat_memory_total() failed (errno=%d)", errno);
 729       assert(0, "perfstat_memory_total() failed");
 730       return false;
 731     }
 732 
 733     assert(rc == 1, "perfstat_memory_total() - weird return code");
 734 
 735     // excerpt from
 736     // http://publib.boulder.ibm.com/infocenter/systems/index.jsp
 737     //        ?topic=/com.ibm.aix.files/doc/aixfiles/libperfstat.h.htm
 738     // The fields of perfstat_memory_total_t:
 739     // u_longlong_t virt_total         Total virtual memory (in 4 KB pages).
 740     // u_longlong_t real_total         Total real memory (in 4 KB pages).
 741     // u_longlong_t real_free          Free real memory (in 4 KB pages).
 742     // u_longlong_t pgsp_total         Total paging space (in 4 KB pages).
 743     // u_longlong_t pgsp_free          Free paging space (in 4 KB pages).
 744 
 745     pmi->virt_total = psmt.virt_total * 4096;
 746     pmi->real_total = psmt.real_total * 4096;
 747     pmi->real_free = psmt.real_free * 4096;
 748     pmi->pgsp_total = psmt.pgsp_total * 4096;
 749     pmi->pgsp_free = psmt.pgsp_free * 4096;
 750 
 751     return true;
 752 
 753   }
 754 } // end os::Aix::get_meminfo
 755 
 756 //////////////////////////////////////////////////////////////////////////////
 757 // create new thread
 758 
 759 // Thread start routine for all newly created threads
 760 static void *thread_native_entry(Thread *thread) {
 761 
 762   // find out my own stack dimensions
 763   {
 764     // actually, this should do exactly the same as thread->record_stack_base_and_size...
 765     thread->set_stack_base(os::current_stack_base());
 766     thread->set_stack_size(os::current_stack_size());
 767   }
 768 
 769   const pthread_t pthread_id = ::pthread_self();
 770   const tid_t kernel_thread_id = ::thread_self();
 771 
 772   LogTarget(Info, os, thread) lt;
 773   if (lt.is_enabled()) {
 774     address low_address = thread->stack_end();
 775     address high_address = thread->stack_base();
 776     lt.print("Thread is alive (tid: " UINTX_FORMAT ", kernel thread id: " UINTX_FORMAT
 777              ", stack [" PTR_FORMAT " - " PTR_FORMAT " (" SIZE_FORMAT "k using %uk pages)).",
 778              os::current_thread_id(), (uintx) kernel_thread_id, low_address, high_address,
 779              (high_address - low_address) / K, os::Aix::query_pagesize(low_address) / K);
 780   }
 781 
 782   // Normally, pthread stacks on AIX live in the data segment (are allocated with malloc()
 783   // by the pthread library). In rare cases, this may not be the case, e.g. when third-party
 784   // tools hook pthread_create(). In this case, we may run into problems establishing
 785   // guard pages on those stacks, because the stacks may reside in memory which is not
 786   // protectable (shmated).
 787   if (thread->stack_base() > ::sbrk(0)) {
 788     log_warning(os, thread)("Thread stack not in data segment.");
 789   }
 790 
 791   // Try to randomize the cache line index of hot stack frames.
 792   // This helps when threads of the same stack traces evict each other's
 793   // cache lines. The threads can be either from the same JVM instance, or
 794   // from different JVM instances. The benefit is especially true for
 795   // processors with hyperthreading technology.
 796 
 797   static int counter = 0;
 798   int pid = os::current_process_id();
 799   alloca(((pid ^ counter++) & 7) * 128);
 800 
 801   thread->initialize_thread_current();
 802 
 803   OSThread* osthread = thread->osthread();
 804 
 805   // Thread_id is pthread id.
 806   osthread->set_thread_id(pthread_id);
 807 
 808   // .. but keep kernel thread id too for diagnostics
 809   osthread->set_kernel_thread_id(kernel_thread_id);
 810 
 811   // Initialize signal mask for this thread.
 812   os::Aix::hotspot_sigmask(thread);
 813 
 814   // Initialize floating point control register.
 815   os::Aix::init_thread_fpu_state();
 816 
 817   assert(osthread->get_state() == RUNNABLE, "invalid os thread state");
 818 
 819   // Call one more level start routine.
 820   thread->run();
 821 
 822   log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", kernel thread id: " UINTX_FORMAT ").",
 823     os::current_thread_id(), (uintx) kernel_thread_id);
 824 
 825   // If a thread has not deleted itself ("delete this") as part of its
 826   // termination sequence, we have to ensure thread-local-storage is
 827   // cleared before we actually terminate. No threads should ever be
 828   // deleted asynchronously with respect to their termination.
 829   if (Thread::current_or_null_safe() != NULL) {
 830     assert(Thread::current_or_null_safe() == thread, "current thread is wrong");
 831     thread->clear_thread_current();
 832   }
 833 
 834   return 0;
 835 }
 836 
 837 bool os::create_thread(Thread* thread, ThreadType thr_type,
 838                        size_t req_stack_size) {
 839 
 840   assert(thread->osthread() == NULL, "caller responsible");
 841 
 842   // Allocate the OSThread object.
 843   OSThread* osthread = new OSThread(NULL, NULL);
 844   if (osthread == NULL) {
 845     return false;
 846   }
 847 
 848   // Set the correct thread state.
 849   osthread->set_thread_type(thr_type);
 850 
 851   // Initial state is ALLOCATED but not INITIALIZED
 852   osthread->set_state(ALLOCATED);
 853 
 854   thread->set_osthread(osthread);
 855 
 856   // Init thread attributes.
 857   pthread_attr_t attr;
 858   pthread_attr_init(&attr);
 859   guarantee(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) == 0, "???");
 860 
 861   // Make sure we run in 1:1 kernel-user-thread mode.
 862   if (os::Aix::on_aix()) {
 863     guarantee(pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM) == 0, "???");
 864     guarantee(pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED) == 0, "???");
 865   }
 866 
 867   // Start in suspended state, and in os::thread_start, wake the thread up.
 868   guarantee(pthread_attr_setsuspendstate_np(&attr, PTHREAD_CREATE_SUSPENDED_NP) == 0, "???");
 869 
 870   // Calculate stack size if it's not specified by caller.
 871   size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
 872 
 873   // JDK-8187028: It was observed that on some configurations (4K backed thread stacks)
 874   // the real thread stack size may be smaller than the requested stack size, by as much as 64K.
 875   // This very much looks like a pthread lib error. As a workaround, increase the stack size
 876   // by 64K for small thread stacks (arbitrarily choosen to be < 4MB)
 877   if (stack_size < 4096 * K) {
 878     stack_size += 64 * K;
 879   }
 880 
 881   // On Aix, pthread_attr_setstacksize fails with huge values and leaves the
 882   // thread size in attr unchanged. If this is the minimal stack size as set
 883   // by pthread_attr_init this leads to crashes after thread creation. E.g. the
 884   // guard pages might not fit on the tiny stack created.
 885   int ret = pthread_attr_setstacksize(&attr, stack_size);
 886   if (ret != 0) {
 887     log_warning(os, thread)("The thread stack size specified is invalid: " SIZE_FORMAT "k",
 888                             stack_size / K);
 889   }
 890 
 891   // Save some cycles and a page by disabling OS guard pages where we have our own
 892   // VM guard pages (in java threads). For other threads, keep system default guard
 893   // pages in place.
 894   if (thr_type == java_thread || thr_type == compiler_thread) {
 895     ret = pthread_attr_setguardsize(&attr, 0);
 896   }
 897 
 898   pthread_t tid = 0;
 899   if (ret == 0) {
 900     ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
 901   }
 902 
 903   if (ret == 0) {
 904     char buf[64];
 905     log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
 906       (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
 907   } else {
 908     char buf[64];
 909     log_warning(os, thread)("Failed to start thread - pthread_create failed (%d=%s) for attributes: %s.",
 910       ret, os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
 911   }
 912 
 913   pthread_attr_destroy(&attr);
 914 
 915   if (ret != 0) {
 916     // Need to clean up stuff we've allocated so far.
 917     thread->set_osthread(NULL);
 918     delete osthread;
 919     return false;
 920   }
 921 
 922   // OSThread::thread_id is the pthread id.
 923   osthread->set_thread_id(tid);
 924 
 925   return true;
 926 }
 927 
 928 /////////////////////////////////////////////////////////////////////////////
 929 // attach existing thread
 930 
 931 // bootstrap the main thread
 932 bool os::create_main_thread(JavaThread* thread) {
 933   assert(os::Aix::_main_thread == pthread_self(), "should be called inside main thread");
 934   return create_attached_thread(thread);
 935 }
 936 
 937 bool os::create_attached_thread(JavaThread* thread) {
 938 #ifdef ASSERT
 939     thread->verify_not_published();
 940 #endif
 941 
 942   // Allocate the OSThread object
 943   OSThread* osthread = new OSThread(NULL, NULL);
 944 
 945   if (osthread == NULL) {
 946     return false;
 947   }
 948 
 949   const pthread_t pthread_id = ::pthread_self();
 950   const tid_t kernel_thread_id = ::thread_self();
 951 
 952   // OSThread::thread_id is the pthread id.
 953   osthread->set_thread_id(pthread_id);
 954 
 955   // .. but keep kernel thread id too for diagnostics
 956   osthread->set_kernel_thread_id(kernel_thread_id);
 957 
 958   // initialize floating point control register
 959   os::Aix::init_thread_fpu_state();
 960 
 961   // Initial thread state is RUNNABLE
 962   osthread->set_state(RUNNABLE);
 963 
 964   thread->set_osthread(osthread);
 965 
 966   if (UseNUMA) {
 967     int lgrp_id = os::numa_get_group_id();
 968     if (lgrp_id != -1) {
 969       thread->set_lgrp_id(lgrp_id);
 970     }
 971   }
 972 
 973   // initialize signal mask for this thread
 974   // and save the caller's signal mask
 975   os::Aix::hotspot_sigmask(thread);
 976 
 977   log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", kernel thread id: " UINTX_FORMAT ").",
 978     os::current_thread_id(), (uintx) kernel_thread_id);
 979 
 980   return true;
 981 }
 982 
 983 void os::pd_start_thread(Thread* thread) {
 984   int status = pthread_continue_np(thread->osthread()->pthread_id());
 985   assert(status == 0, "thr_continue failed");
 986 }
 987 
 988 // Free OS resources related to the OSThread
 989 void os::free_thread(OSThread* osthread) {
 990   assert(osthread != NULL, "osthread not set");
 991 
 992   // We are told to free resources of the argument thread,
 993   // but we can only really operate on the current thread.
 994   assert(Thread::current()->osthread() == osthread,
 995          "os::free_thread but not current thread");
 996 
 997   // Restore caller's signal mask
 998   sigset_t sigmask = osthread->caller_sigmask();
 999   pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1000 
1001   delete osthread;
1002 }
1003 
1004 ////////////////////////////////////////////////////////////////////////////////
1005 // time support
1006 
1007 // Time since start-up in seconds to a fine granularity.
1008 // Used by VMSelfDestructTimer and the MemProfiler.
1009 double os::elapsedTime() {
1010   return (double)(os::elapsed_counter()) * 0.000001;
1011 }
1012 
1013 jlong os::elapsed_counter() {
1014   timeval time;
1015   int status = gettimeofday(&time, NULL);
1016   return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1017 }
1018 
1019 jlong os::elapsed_frequency() {
1020   return (1000 * 1000);
1021 }
1022 
1023 bool os::supports_vtime() { return true; }
1024 bool os::enable_vtime()   { return false; }
1025 bool os::vtime_enabled()  { return false; }
1026 
1027 double os::elapsedVTime() {
1028   struct rusage usage;
1029   int retval = getrusage(RUSAGE_THREAD, &usage);
1030   if (retval == 0) {
1031     return usage.ru_utime.tv_sec + usage.ru_stime.tv_sec + (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000.0 * 1000);
1032   } else {
1033     // better than nothing, but not much
1034     return elapsedTime();
1035   }
1036 }
1037 
1038 jlong os::javaTimeMillis() {
1039   timeval time;
1040   int status = gettimeofday(&time, NULL);
1041   assert(status != -1, "aix error at gettimeofday()");
1042   return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1043 }
1044 
1045 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1046   timeval time;
1047   int status = gettimeofday(&time, NULL);
1048   assert(status != -1, "aix error at gettimeofday()");
1049   seconds = jlong(time.tv_sec);
1050   nanos = jlong(time.tv_usec) * 1000;
1051 }
1052 
1053 jlong os::javaTimeNanos() {
1054   if (os::Aix::on_pase()) {
1055 
1056     timeval time;
1057     int status = gettimeofday(&time, NULL);
1058     assert(status != -1, "PASE error at gettimeofday()");
1059     jlong usecs = jlong((unsigned long long) time.tv_sec * (1000 * 1000) + time.tv_usec);
1060     return 1000 * usecs;
1061 
1062   } else {
1063     // On AIX use the precision of processors real time clock
1064     // or time base registers.
1065     timebasestruct_t time;
1066     int rc;
1067 
1068     // If the CPU has a time register, it will be used and
1069     // we have to convert to real time first. After convertion we have following data:
1070     // time.tb_high [seconds since 00:00:00 UTC on 1.1.1970]
1071     // time.tb_low  [nanoseconds after the last full second above]
1072     // We better use mread_real_time here instead of read_real_time
1073     // to ensure that we will get a monotonic increasing time.
1074     if (mread_real_time(&time, TIMEBASE_SZ) != RTC_POWER) {
1075       rc = time_base_to_time(&time, TIMEBASE_SZ);
1076       assert(rc != -1, "aix error at time_base_to_time()");
1077     }
1078     return jlong(time.tb_high) * (1000 * 1000 * 1000) + jlong(time.tb_low);
1079   }
1080 }
1081 
1082 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1083   info_ptr->max_value = ALL_64_BITS;
1084   // mread_real_time() is monotonic (see 'os::javaTimeNanos()')
1085   info_ptr->may_skip_backward = false;
1086   info_ptr->may_skip_forward = false;
1087   info_ptr->kind = JVMTI_TIMER_ELAPSED;    // elapsed not CPU time
1088 }
1089 
1090 // Return the real, user, and system times in seconds from an
1091 // arbitrary fixed point in the past.
1092 bool os::getTimesSecs(double* process_real_time,
1093                       double* process_user_time,
1094                       double* process_system_time) {
1095   struct tms ticks;
1096   clock_t real_ticks = times(&ticks);
1097 
1098   if (real_ticks == (clock_t) (-1)) {
1099     return false;
1100   } else {
1101     double ticks_per_second = (double) clock_tics_per_sec;
1102     *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1103     *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1104     *process_real_time = ((double) real_ticks) / ticks_per_second;
1105 
1106     return true;
1107   }
1108 }
1109 
1110 char * os::local_time_string(char *buf, size_t buflen) {
1111   struct tm t;
1112   time_t long_time;
1113   time(&long_time);
1114   localtime_r(&long_time, &t);
1115   jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1116                t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1117                t.tm_hour, t.tm_min, t.tm_sec);
1118   return buf;
1119 }
1120 
1121 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1122   return localtime_r(clock, res);
1123 }
1124 
1125 ////////////////////////////////////////////////////////////////////////////////
1126 // runtime exit support
1127 
1128 // Note: os::shutdown() might be called very early during initialization, or
1129 // called from signal handler. Before adding something to os::shutdown(), make
1130 // sure it is async-safe and can handle partially initialized VM.
1131 void os::shutdown() {
1132 
1133   // allow PerfMemory to attempt cleanup of any persistent resources
1134   perfMemory_exit();
1135 
1136   // needs to remove object in file system
1137   AttachListener::abort();
1138 
1139   // flush buffered output, finish log files
1140   ostream_abort();
1141 
1142   // Check for abort hook
1143   abort_hook_t abort_hook = Arguments::abort_hook();
1144   if (abort_hook != NULL) {
1145     abort_hook();
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, void* siginfo, const void* context) {
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   ::abort();
1172 }
1173 
1174 // This method is a copy of JDK's sysGetLastErrorString
1175 // from src/solaris/hpi/src/system_md.c
1176 
1177 size_t os::lasterror(char *buf, size_t len) {
1178   if (errno == 0) return 0;
1179 
1180   const char *s = os::strerror(errno);
1181   size_t n = ::strlen(s);
1182   if (n >= len) {
1183     n = len - 1;
1184   }
1185   ::strncpy(buf, s, n);
1186   buf[n] = '\0';
1187   return n;
1188 }
1189 
1190 intx os::current_thread_id() {
1191   return (intx)pthread_self();
1192 }
1193 
1194 int os::current_process_id() {
1195   return getpid();
1196 }
1197 
1198 // DLL functions
1199 
1200 const char* os::dll_file_extension() { return ".so"; }
1201 
1202 // This must be hard coded because it's the system's temporary
1203 // directory not the java application's temp directory, ala java.io.tmpdir.
1204 const char* os::get_temp_directory() { return "/tmp"; }
1205 
1206 // Check if addr is inside libjvm.so.
1207 bool os::address_is_in_vm(address addr) {
1208 
1209   // Input could be a real pc or a function pointer literal. The latter
1210   // would be a function descriptor residing in the data segment of a module.
1211   loaded_module_t lm;
1212   if (LoadedLibraries::find_for_text_address(addr, &lm) != NULL) {
1213     return lm.is_in_vm;
1214   } else if (LoadedLibraries::find_for_data_address(addr, &lm) != NULL) {
1215     return lm.is_in_vm;
1216   } else {
1217     return false;
1218   }
1219 
1220 }
1221 
1222 // Resolve an AIX function descriptor literal to a code pointer.
1223 // If the input is a valid code pointer to a text segment of a loaded module,
1224 //   it is returned unchanged.
1225 // If the input is a valid AIX function descriptor, it is resolved to the
1226 //   code entry point.
1227 // If the input is neither a valid function descriptor nor a valid code pointer,
1228 //   NULL is returned.
1229 static address resolve_function_descriptor_to_code_pointer(address p) {
1230 
1231   if (LoadedLibraries::find_for_text_address(p, NULL) != NULL) {
1232     // It is a real code pointer.
1233     return p;
1234   } else if (LoadedLibraries::find_for_data_address(p, NULL) != NULL) {
1235     // Pointer to data segment, potential function descriptor.
1236     address code_entry = (address)(((FunctionDescriptor*)p)->entry());
1237     if (LoadedLibraries::find_for_text_address(code_entry, NULL) != NULL) {
1238       // It is a function descriptor.
1239       return code_entry;
1240     }
1241   }
1242 
1243   return NULL;
1244 }
1245 
1246 bool os::dll_address_to_function_name(address addr, char *buf,
1247                                       int buflen, int *offset,
1248                                       bool demangle) {
1249   if (offset) {
1250     *offset = -1;
1251   }
1252   // Buf is not optional, but offset is optional.
1253   assert(buf != NULL, "sanity check");
1254   buf[0] = '\0';
1255 
1256   // Resolve function ptr literals first.
1257   addr = resolve_function_descriptor_to_code_pointer(addr);
1258   if (!addr) {
1259     return false;
1260   }
1261 
1262   return AixSymbols::get_function_name(addr, buf, buflen, offset, NULL, demangle);
1263 }
1264 
1265 bool os::dll_address_to_library_name(address addr, char* buf,
1266                                      int buflen, int* offset) {
1267   if (offset) {
1268     *offset = -1;
1269   }
1270   // Buf is not optional, but offset is optional.
1271   assert(buf != NULL, "sanity check");
1272   buf[0] = '\0';
1273 
1274   // Resolve function ptr literals first.
1275   addr = resolve_function_descriptor_to_code_pointer(addr);
1276   if (!addr) {
1277     return false;
1278   }
1279 
1280   return AixSymbols::get_module_name(addr, buf, buflen);
1281 }
1282 
1283 // Loads .dll/.so and in case of error it checks if .dll/.so was built
1284 // for the same architecture as Hotspot is running on.
1285 void *os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1286 
1287   if (ebuf && ebuflen > 0) {
1288     ebuf[0] = '\0';
1289     ebuf[ebuflen - 1] = '\0';
1290   }
1291 
1292   if (!filename || strlen(filename) == 0) {
1293     ::strncpy(ebuf, "dll_load: empty filename specified", ebuflen - 1);
1294     return NULL;
1295   }
1296 
1297   // RTLD_LAZY is currently not implemented. The dl is loaded immediately with all its dependants.
1298   void * result= ::dlopen(filename, RTLD_LAZY);
1299   if (result != NULL) {
1300     // Reload dll cache. Don't do this in signal handling.
1301     LoadedLibraries::reload();
1302     return result;
1303   } else {
1304     // error analysis when dlopen fails
1305     const char* const error_report = ::dlerror();
1306     if (error_report && ebuf && ebuflen > 0) {
1307       snprintf(ebuf, ebuflen - 1, "%s, LIBPATH=%s, LD_LIBRARY_PATH=%s : %s",
1308                filename, ::getenv("LIBPATH"), ::getenv("LD_LIBRARY_PATH"), error_report);
1309     }
1310   }
1311   return NULL;
1312 }
1313 
1314 void* os::dll_lookup(void* handle, const char* name) {
1315   void* res = dlsym(handle, name);
1316   return res;
1317 }
1318 
1319 void* os::get_default_process_handle() {
1320   return (void*)::dlopen(NULL, RTLD_LAZY);
1321 }
1322 
1323 void os::print_dll_info(outputStream *st) {
1324   st->print_cr("Dynamic libraries:");
1325   LoadedLibraries::print(st);
1326 }
1327 
1328 void os::get_summary_os_info(char* buf, size_t buflen) {
1329   // There might be something more readable than uname results for AIX.
1330   struct utsname name;
1331   uname(&name);
1332   snprintf(buf, buflen, "%s %s", name.release, name.version);
1333 }
1334 
1335 void os::print_os_info(outputStream* st) {
1336   st->print("OS:");
1337 
1338   st->print("uname:");
1339   struct utsname name;
1340   uname(&name);
1341   st->print(name.sysname); st->print(" ");
1342   st->print(name.nodename); st->print(" ");
1343   st->print(name.release); st->print(" ");
1344   st->print(name.version); st->print(" ");
1345   st->print(name.machine);
1346   st->cr();
1347 
1348   uint32_t ver = os::Aix::os_version();
1349   st->print_cr("AIX kernel version %u.%u.%u.%u",
1350                (ver >> 24) & 0xFF, (ver >> 16) & 0xFF, (ver >> 8) & 0xFF, ver & 0xFF);
1351 
1352   os::Posix::print_rlimit_info(st);
1353 
1354   // load average
1355   st->print("load average:");
1356   double loadavg[3] = {-1.L, -1.L, -1.L};
1357   os::loadavg(loadavg, 3);
1358   st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
1359   st->cr();
1360 
1361   // print wpar info
1362   libperfstat::wparinfo_t wi;
1363   if (libperfstat::get_wparinfo(&wi)) {
1364     st->print_cr("wpar info");
1365     st->print_cr("name: %s", wi.name);
1366     st->print_cr("id:   %d", wi.wpar_id);
1367     st->print_cr("type: %s", (wi.app_wpar ? "application" : "system"));
1368   }
1369 
1370   // print partition info
1371   libperfstat::partitioninfo_t pi;
1372   if (libperfstat::get_partitioninfo(&pi)) {
1373     st->print_cr("partition info");
1374     st->print_cr(" name: %s", pi.name);
1375   }
1376 
1377 }
1378 
1379 void os::print_memory_info(outputStream* st) {
1380 
1381   st->print_cr("Memory:");
1382 
1383   st->print_cr("  Base page size (sysconf _SC_PAGESIZE):  %s",
1384     describe_pagesize(g_multipage_support.pagesize));
1385   st->print_cr("  Data page size (C-Heap, bss, etc):      %s",
1386     describe_pagesize(g_multipage_support.datapsize));
1387   st->print_cr("  Text page size:                         %s",
1388     describe_pagesize(g_multipage_support.textpsize));
1389   st->print_cr("  Thread stack page size (pthread):       %s",
1390     describe_pagesize(g_multipage_support.pthr_stack_pagesize));
1391   st->print_cr("  Default shared memory page size:        %s",
1392     describe_pagesize(g_multipage_support.shmpsize));
1393   st->print_cr("  Can use 64K pages dynamically with shared meory:  %s",
1394     (g_multipage_support.can_use_64K_pages ? "yes" :"no"));
1395   st->print_cr("  Can use 16M pages dynamically with shared memory: %s",
1396     (g_multipage_support.can_use_16M_pages ? "yes" :"no"));
1397   st->print_cr("  Multipage error: %d",
1398     g_multipage_support.error);
1399   st->cr();
1400   st->print_cr("  os::vm_page_size:       %s", describe_pagesize(os::vm_page_size()));
1401 
1402   // print out LDR_CNTRL because it affects the default page sizes
1403   const char* const ldr_cntrl = ::getenv("LDR_CNTRL");
1404   st->print_cr("  LDR_CNTRL=%s.", ldr_cntrl ? ldr_cntrl : "<unset>");
1405 
1406   // Print out EXTSHM because it is an unsupported setting.
1407   const char* const extshm = ::getenv("EXTSHM");
1408   st->print_cr("  EXTSHM=%s.", extshm ? extshm : "<unset>");
1409   if ( (strcmp(extshm, "on") == 0) || (strcmp(extshm, "ON") == 0) ) {
1410     st->print_cr("  *** Unsupported! Please remove EXTSHM from your environment! ***");
1411   }
1412 
1413   // Print out AIXTHREAD_GUARDPAGES because it affects the size of pthread stacks.
1414   const char* const aixthread_guardpages = ::getenv("AIXTHREAD_GUARDPAGES");
1415   st->print_cr("  AIXTHREAD_GUARDPAGES=%s.",
1416       aixthread_guardpages ? aixthread_guardpages : "<unset>");
1417 
1418   os::Aix::meminfo_t mi;
1419   if (os::Aix::get_meminfo(&mi)) {
1420     char buffer[256];
1421     if (os::Aix::on_aix()) {
1422       st->print_cr("physical total : " SIZE_FORMAT, mi.real_total);
1423       st->print_cr("physical free  : " SIZE_FORMAT, mi.real_free);
1424       st->print_cr("swap total     : " SIZE_FORMAT, mi.pgsp_total);
1425       st->print_cr("swap free      : " SIZE_FORMAT, mi.pgsp_free);
1426     } else {
1427       // PASE - Numbers are result of QWCRSSTS; they mean:
1428       // real_total: Sum of all system pools
1429       // real_free: always 0
1430       // pgsp_total: we take the size of the system ASP
1431       // pgsp_free: size of system ASP times percentage of system ASP unused
1432       st->print_cr("physical total     : " SIZE_FORMAT, mi.real_total);
1433       st->print_cr("system asp total   : " SIZE_FORMAT, mi.pgsp_total);
1434       st->print_cr("%% system asp used : " SIZE_FORMAT,
1435         mi.pgsp_total ? (100.0f * (mi.pgsp_total - mi.pgsp_free) / mi.pgsp_total) : -1.0f);
1436     }
1437     st->print_raw(buffer);
1438   }
1439   st->cr();
1440 
1441   // Print segments allocated with os::reserve_memory.
1442   st->print_cr("internal virtual memory regions used by vm:");
1443   vmembk_print_on(st);
1444 }
1445 
1446 // Get a string for the cpuinfo that is a summary of the cpu type
1447 void os::get_summary_cpu_info(char* buf, size_t buflen) {
1448   // This looks good
1449   libperfstat::cpuinfo_t ci;
1450   if (libperfstat::get_cpuinfo(&ci)) {
1451     strncpy(buf, ci.version, buflen);
1452   } else {
1453     strncpy(buf, "AIX", buflen);
1454   }
1455 }
1456 
1457 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
1458   // Nothing to do beyond what os::print_cpu_info() does.
1459 }
1460 
1461 static void print_signal_handler(outputStream* st, int sig,
1462                                  char* buf, size_t buflen);
1463 
1464 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
1465   st->print_cr("Signal Handlers:");
1466   print_signal_handler(st, SIGSEGV, buf, buflen);
1467   print_signal_handler(st, SIGBUS , buf, buflen);
1468   print_signal_handler(st, SIGFPE , buf, buflen);
1469   print_signal_handler(st, SIGPIPE, buf, buflen);
1470   print_signal_handler(st, SIGXFSZ, buf, buflen);
1471   print_signal_handler(st, SIGILL , buf, buflen);
1472   print_signal_handler(st, SR_signum, buf, buflen);
1473   print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
1474   print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
1475   print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
1476   print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
1477   print_signal_handler(st, SIGTRAP, buf, buflen);
1478   // We also want to know if someone else adds a SIGDANGER handler because
1479   // that will interfere with OOM killling.
1480   print_signal_handler(st, SIGDANGER, buf, buflen);
1481 }
1482 
1483 static char saved_jvm_path[MAXPATHLEN] = {0};
1484 
1485 // Find the full path to the current module, libjvm.so.
1486 void os::jvm_path(char *buf, jint buflen) {
1487   // Error checking.
1488   if (buflen < MAXPATHLEN) {
1489     assert(false, "must use a large-enough buffer");
1490     buf[0] = '\0';
1491     return;
1492   }
1493   // Lazy resolve the path to current module.
1494   if (saved_jvm_path[0] != 0) {
1495     strcpy(buf, saved_jvm_path);
1496     return;
1497   }
1498 
1499   Dl_info dlinfo;
1500   int ret = dladdr(CAST_FROM_FN_PTR(void *, os::jvm_path), &dlinfo);
1501   assert(ret != 0, "cannot locate libjvm");
1502   char* rp = os::Posix::realpath((char *)dlinfo.dli_fname, buf, buflen);
1503   assert(rp != NULL, "error in realpath(): maybe the 'path' argument is too long?");
1504 
1505   if (Arguments::sun_java_launcher_is_altjvm()) {
1506     // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
1507     // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
1508     // If "/jre/lib/" appears at the right place in the string, then
1509     // assume we are installed in a JDK and we're done. Otherwise, check
1510     // for a JAVA_HOME environment variable and fix up the path so it
1511     // looks like libjvm.so is installed there (append a fake suffix
1512     // hotspot/libjvm.so).
1513     const char *p = buf + strlen(buf) - 1;
1514     for (int count = 0; p > buf && count < 4; ++count) {
1515       for (--p; p > buf && *p != '/'; --p)
1516         /* empty */ ;
1517     }
1518 
1519     if (strncmp(p, "/jre/lib/", 9) != 0) {
1520       // Look for JAVA_HOME in the environment.
1521       char* java_home_var = ::getenv("JAVA_HOME");
1522       if (java_home_var != NULL && java_home_var[0] != 0) {
1523         char* jrelib_p;
1524         int len;
1525 
1526         // Check the current module name "libjvm.so".
1527         p = strrchr(buf, '/');
1528         if (p == NULL) {
1529           return;
1530         }
1531         assert(strstr(p, "/libjvm") == p, "invalid library name");
1532 
1533         rp = os::Posix::realpath(java_home_var, buf, buflen);
1534         if (rp == NULL) {
1535           return;
1536         }
1537 
1538         // determine if this is a legacy image or modules image
1539         // modules image doesn't have "jre" subdirectory
1540         len = strlen(buf);
1541         assert(len < buflen, "Ran out of buffer room");
1542         jrelib_p = buf + len;
1543         snprintf(jrelib_p, buflen-len, "/jre/lib");
1544         if (0 != access(buf, F_OK)) {
1545           snprintf(jrelib_p, buflen-len, "/lib");
1546         }
1547 
1548         if (0 == access(buf, F_OK)) {
1549           // Use current module name "libjvm.so"
1550           len = strlen(buf);
1551           snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
1552         } else {
1553           // Go back to path of .so
1554           rp = os::Posix::realpath((char *)dlinfo.dli_fname, buf, buflen);
1555           if (rp == NULL) {
1556             return;
1557           }
1558         }
1559       }
1560     }
1561   }
1562 
1563   strncpy(saved_jvm_path, buf, sizeof(saved_jvm_path));
1564   saved_jvm_path[sizeof(saved_jvm_path) - 1] = '\0';
1565 }
1566 
1567 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
1568   // no prefix required, not even "_"
1569 }
1570 
1571 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
1572   // no suffix required
1573 }
1574 
1575 ////////////////////////////////////////////////////////////////////////////////
1576 // sun.misc.Signal support
1577 
1578 static volatile jint sigint_count = 0;
1579 
1580 static void
1581 UserHandler(int sig, void *siginfo, void *context) {
1582   // 4511530 - sem_post is serialized and handled by the manager thread. When
1583   // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
1584   // don't want to flood the manager thread with sem_post requests.
1585   if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
1586     return;
1587 
1588   // Ctrl-C is pressed during error reporting, likely because the error
1589   // handler fails to abort. Let VM die immediately.
1590   if (sig == SIGINT && VMError::is_error_reported()) {
1591     os::die();
1592   }
1593 
1594   os::signal_notify(sig);
1595 }
1596 
1597 void* os::user_handler() {
1598   return CAST_FROM_FN_PTR(void*, UserHandler);
1599 }
1600 
1601 extern "C" {
1602   typedef void (*sa_handler_t)(int);
1603   typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
1604 }
1605 
1606 void* os::signal(int signal_number, void* handler) {
1607   struct sigaction sigAct, oldSigAct;
1608 
1609   sigfillset(&(sigAct.sa_mask));
1610 
1611   // Do not block out synchronous signals in the signal handler.
1612   // Blocking synchronous signals only makes sense if you can really
1613   // be sure that those signals won't happen during signal handling,
1614   // when the blocking applies. Normal signal handlers are lean and
1615   // do not cause signals. But our signal handlers tend to be "risky"
1616   // - secondary SIGSEGV, SIGILL, SIGBUS' may and do happen.
1617   // On AIX, PASE there was a case where a SIGSEGV happened, followed
1618   // by a SIGILL, which was blocked due to the signal mask. The process
1619   // just hung forever. Better to crash from a secondary signal than to hang.
1620   sigdelset(&(sigAct.sa_mask), SIGSEGV);
1621   sigdelset(&(sigAct.sa_mask), SIGBUS);
1622   sigdelset(&(sigAct.sa_mask), SIGILL);
1623   sigdelset(&(sigAct.sa_mask), SIGFPE);
1624   sigdelset(&(sigAct.sa_mask), SIGTRAP);
1625 
1626   sigAct.sa_flags   = SA_RESTART|SA_SIGINFO;
1627 
1628   sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
1629 
1630   if (sigaction(signal_number, &sigAct, &oldSigAct)) {
1631     // -1 means registration failed
1632     return (void *)-1;
1633   }
1634 
1635   return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
1636 }
1637 
1638 void os::signal_raise(int signal_number) {
1639   ::raise(signal_number);
1640 }
1641 
1642 //
1643 // The following code is moved from os.cpp for making this
1644 // code platform specific, which it is by its very nature.
1645 //
1646 
1647 // Will be modified when max signal is changed to be dynamic
1648 int os::sigexitnum_pd() {
1649   return NSIG;
1650 }
1651 
1652 // a counter for each possible signal value
1653 static volatile jint pending_signals[NSIG+1] = { 0 };
1654 
1655 // Wrapper functions for: sem_init(), sem_post(), sem_wait()
1656 // On AIX, we use sem_init(), sem_post(), sem_wait()
1657 // On Pase, we need to use msem_lock() and msem_unlock(), because Posix Semaphores
1658 // do not seem to work at all on PASE (unimplemented, will cause SIGILL).
1659 // Note that just using msem_.. APIs for both PASE and AIX is not an option either, as
1660 // on AIX, msem_..() calls are suspected of causing problems.
1661 static sem_t sig_sem;
1662 static msemaphore* p_sig_msem = 0;
1663 
1664 static void local_sem_init() {
1665   if (os::Aix::on_aix()) {
1666     int rc = ::sem_init(&sig_sem, 0, 0);
1667     guarantee(rc != -1, "sem_init failed");
1668   } else {
1669     // Memory semaphores must live in shared mem.
1670     guarantee0(p_sig_msem == NULL);
1671     p_sig_msem = (msemaphore*)os::reserve_memory(sizeof(msemaphore), NULL);
1672     guarantee(p_sig_msem, "Cannot allocate memory for memory semaphore");
1673     guarantee(::msem_init(p_sig_msem, 0) == p_sig_msem, "msem_init failed");
1674   }
1675 }
1676 
1677 static void local_sem_post() {
1678   static bool warn_only_once = false;
1679   if (os::Aix::on_aix()) {
1680     int rc = ::sem_post(&sig_sem);
1681     if (rc == -1 && !warn_only_once) {
1682       trcVerbose("sem_post failed (errno = %d, %s)", errno, os::errno_name(errno));
1683       warn_only_once = true;
1684     }
1685   } else {
1686     guarantee0(p_sig_msem != NULL);
1687     int rc = ::msem_unlock(p_sig_msem, 0);
1688     if (rc == -1 && !warn_only_once) {
1689       trcVerbose("msem_unlock failed (errno = %d, %s)", errno, os::errno_name(errno));
1690       warn_only_once = true;
1691     }
1692   }
1693 }
1694 
1695 static void local_sem_wait() {
1696   static bool warn_only_once = false;
1697   if (os::Aix::on_aix()) {
1698     int rc = ::sem_wait(&sig_sem);
1699     if (rc == -1 && !warn_only_once) {
1700       trcVerbose("sem_wait failed (errno = %d, %s)", errno, os::errno_name(errno));
1701       warn_only_once = true;
1702     }
1703   } else {
1704     guarantee0(p_sig_msem != NULL); // must init before use
1705     int rc = ::msem_lock(p_sig_msem, 0);
1706     if (rc == -1 && !warn_only_once) {
1707       trcVerbose("msem_lock failed (errno = %d, %s)", errno, os::errno_name(errno));
1708       warn_only_once = true;
1709     }
1710   }
1711 }
1712 
1713 void os::signal_init_pd() {
1714   // Initialize signal structures
1715   ::memset((void*)pending_signals, 0, sizeof(pending_signals));
1716 
1717   // Initialize signal semaphore
1718   local_sem_init();
1719 }
1720 
1721 void os::signal_notify(int sig) {
1722   Atomic::inc(&pending_signals[sig]);
1723   local_sem_post();
1724 }
1725 
1726 static int check_pending_signals(bool wait) {
1727   Atomic::store(0, &sigint_count);
1728   for (;;) {
1729     for (int i = 0; i < NSIG + 1; i++) {
1730       jint n = pending_signals[i];
1731       if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
1732         return i;
1733       }
1734     }
1735     if (!wait) {
1736       return -1;
1737     }
1738     JavaThread *thread = JavaThread::current();
1739     ThreadBlockInVM tbivm(thread);
1740 
1741     bool threadIsSuspended;
1742     do {
1743       thread->set_suspend_equivalent();
1744       // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
1745 
1746       local_sem_wait();
1747 
1748       // were we externally suspended while we were waiting?
1749       threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
1750       if (threadIsSuspended) {
1751         //
1752         // The semaphore has been incremented, but while we were waiting
1753         // another thread suspended us. We don't want to continue running
1754         // while suspended because that would surprise the thread that
1755         // suspended us.
1756         //
1757 
1758         local_sem_post();
1759 
1760         thread->java_suspend_self();
1761       }
1762     } while (threadIsSuspended);
1763   }
1764 }
1765 
1766 int os::signal_lookup() {
1767   return check_pending_signals(false);
1768 }
1769 
1770 int os::signal_wait() {
1771   return check_pending_signals(true);
1772 }
1773 
1774 ////////////////////////////////////////////////////////////////////////////////
1775 // Virtual Memory
1776 
1777 // We need to keep small simple bookkeeping for os::reserve_memory and friends.
1778 
1779 #define VMEM_MAPPED  1
1780 #define VMEM_SHMATED 2
1781 
1782 struct vmembk_t {
1783   int type;         // 1 - mmap, 2 - shmat
1784   char* addr;
1785   size_t size;      // Real size, may be larger than usersize.
1786   size_t pagesize;  // page size of area
1787   vmembk_t* next;
1788 
1789   bool contains_addr(char* p) const {
1790     return p >= addr && p < (addr + size);
1791   }
1792 
1793   bool contains_range(char* p, size_t s) const {
1794     return contains_addr(p) && contains_addr(p + s - 1);
1795   }
1796 
1797   void print_on(outputStream* os) const {
1798     os->print("[" PTR_FORMAT " - " PTR_FORMAT "] (" UINTX_FORMAT
1799       " bytes, %d %s pages), %s",
1800       addr, addr + size - 1, size, size / pagesize, describe_pagesize(pagesize),
1801       (type == VMEM_SHMATED ? "shmat" : "mmap")
1802     );
1803   }
1804 
1805   // Check that range is a sub range of memory block (or equal to memory block);
1806   // also check that range is fully page aligned to the page size if the block.
1807   void assert_is_valid_subrange(char* p, size_t s) const {
1808     if (!contains_range(p, s)) {
1809       trcVerbose("[" PTR_FORMAT " - " PTR_FORMAT "] is not a sub "
1810               "range of [" PTR_FORMAT " - " PTR_FORMAT "].",
1811               p, p + s, addr, addr + size);
1812       guarantee0(false);
1813     }
1814     if (!is_aligned_to(p, pagesize) || !is_aligned_to(p + s, pagesize)) {
1815       trcVerbose("range [" PTR_FORMAT " - " PTR_FORMAT "] is not"
1816               " aligned to pagesize (%lu)", p, p + s, (unsigned long) pagesize);
1817       guarantee0(false);
1818     }
1819   }
1820 };
1821 
1822 static struct {
1823   vmembk_t* first;
1824   MiscUtils::CritSect cs;
1825 } vmem;
1826 
1827 static void vmembk_add(char* addr, size_t size, size_t pagesize, int type) {
1828   vmembk_t* p = (vmembk_t*) ::malloc(sizeof(vmembk_t));
1829   assert0(p);
1830   if (p) {
1831     MiscUtils::AutoCritSect lck(&vmem.cs);
1832     p->addr = addr; p->size = size;
1833     p->pagesize = pagesize;
1834     p->type = type;
1835     p->next = vmem.first;
1836     vmem.first = p;
1837   }
1838 }
1839 
1840 static vmembk_t* vmembk_find(char* addr) {
1841   MiscUtils::AutoCritSect lck(&vmem.cs);
1842   for (vmembk_t* p = vmem.first; p; p = p->next) {
1843     if (p->addr <= addr && (p->addr + p->size) > addr) {
1844       return p;
1845     }
1846   }
1847   return NULL;
1848 }
1849 
1850 static void vmembk_remove(vmembk_t* p0) {
1851   MiscUtils::AutoCritSect lck(&vmem.cs);
1852   assert0(p0);
1853   assert0(vmem.first); // List should not be empty.
1854   for (vmembk_t** pp = &(vmem.first); *pp; pp = &((*pp)->next)) {
1855     if (*pp == p0) {
1856       *pp = p0->next;
1857       ::free(p0);
1858       return;
1859     }
1860   }
1861   assert0(false); // Not found?
1862 }
1863 
1864 static void vmembk_print_on(outputStream* os) {
1865   MiscUtils::AutoCritSect lck(&vmem.cs);
1866   for (vmembk_t* vmi = vmem.first; vmi; vmi = vmi->next) {
1867     vmi->print_on(os);
1868     os->cr();
1869   }
1870 }
1871 
1872 // Reserve and attach a section of System V memory.
1873 // If <requested_addr> is not NULL, function will attempt to attach the memory at the given
1874 // address. Failing that, it will attach the memory anywhere.
1875 // If <requested_addr> is NULL, function will attach the memory anywhere.
1876 //
1877 // <alignment_hint> is being ignored by this function. It is very probable however that the
1878 // alignment requirements are met anyway, because shmat() attaches at 256M boundaries.
1879 // Should this be not enogh, we can put more work into it.
1880 static char* reserve_shmated_memory (
1881   size_t bytes,
1882   char* requested_addr,
1883   size_t alignment_hint) {
1884 
1885   trcVerbose("reserve_shmated_memory " UINTX_FORMAT " bytes, wishaddress "
1886     PTR_FORMAT ", alignment_hint " UINTX_FORMAT "...",
1887     bytes, requested_addr, alignment_hint);
1888 
1889   // Either give me wish address or wish alignment but not both.
1890   assert0(!(requested_addr != NULL && alignment_hint != 0));
1891 
1892   // We must prevent anyone from attaching too close to the
1893   // BRK because that may cause malloc OOM.
1894   if (requested_addr != NULL && is_close_to_brk((address)requested_addr)) {
1895     trcVerbose("Wish address " PTR_FORMAT " is too close to the BRK segment. "
1896       "Will attach anywhere.", requested_addr);
1897     // Act like the OS refused to attach there.
1898     requested_addr = NULL;
1899   }
1900 
1901   // For old AS/400's (V5R4 and older) we should not even be here - System V shared memory is not
1902   // really supported (max size 4GB), so reserve_mmapped_memory should have been used instead.
1903   if (os::Aix::on_pase_V5R4_or_older()) {
1904     ShouldNotReachHere();
1905   }
1906 
1907   // Align size of shm up to 64K to avoid errors if we later try to change the page size.
1908   const size_t size = align_up(bytes, 64*K);
1909 
1910   // Reserve the shared segment.
1911   int shmid = shmget(IPC_PRIVATE, size, IPC_CREAT | S_IRUSR | S_IWUSR);
1912   if (shmid == -1) {
1913     trcVerbose("shmget(.., " UINTX_FORMAT ", ..) failed (errno: %d).", size, errno);
1914     return NULL;
1915   }
1916 
1917   // Important note:
1918   // It is very important that we, upon leaving this function, do not leave a shm segment alive.
1919   // We must right after attaching it remove it from the system. System V shm segments are global and
1920   // survive the process.
1921   // So, from here on: Do not assert, do not return, until we have called shmctl(IPC_RMID) (A).
1922 
1923   struct shmid_ds shmbuf;
1924   memset(&shmbuf, 0, sizeof(shmbuf));
1925   shmbuf.shm_pagesize = 64*K;
1926   if (shmctl(shmid, SHM_PAGESIZE, &shmbuf) != 0) {
1927     trcVerbose("Failed to set page size (need " UINTX_FORMAT " 64K pages) - shmctl failed with %d.",
1928                size / (64*K), errno);
1929     // I want to know if this ever happens.
1930     assert(false, "failed to set page size for shmat");
1931   }
1932 
1933   // Now attach the shared segment.
1934   // Note that I attach with SHM_RND - which means that the requested address is rounded down, if
1935   // needed, to the next lowest segment boundary. Otherwise the attach would fail if the address
1936   // were not a segment boundary.
1937   char* const addr = (char*) shmat(shmid, requested_addr, SHM_RND);
1938   const int errno_shmat = errno;
1939 
1940   // (A) Right after shmat and before handing shmat errors delete the shm segment.
1941   if (::shmctl(shmid, IPC_RMID, NULL) == -1) {
1942     trcVerbose("shmctl(%u, IPC_RMID) failed (%d)\n", shmid, errno);
1943     assert(false, "failed to remove shared memory segment!");
1944   }
1945 
1946   // Handle shmat error. If we failed to attach, just return.
1947   if (addr == (char*)-1) {
1948     trcVerbose("Failed to attach segment at " PTR_FORMAT " (%d).", requested_addr, errno_shmat);
1949     return NULL;
1950   }
1951 
1952   // Just for info: query the real page size. In case setting the page size did not
1953   // work (see above), the system may have given us something other then 4K (LDR_CNTRL).
1954   const size_t real_pagesize = os::Aix::query_pagesize(addr);
1955   if (real_pagesize != shmbuf.shm_pagesize) {
1956     trcVerbose("pagesize is, surprisingly, %h.", real_pagesize);
1957   }
1958 
1959   if (addr) {
1960     trcVerbose("shm-allocated " PTR_FORMAT " .. " PTR_FORMAT " (" UINTX_FORMAT " bytes, " UINTX_FORMAT " %s pages)",
1961       addr, addr + size - 1, size, size/real_pagesize, describe_pagesize(real_pagesize));
1962   } else {
1963     if (requested_addr != NULL) {
1964       trcVerbose("failed to shm-allocate " UINTX_FORMAT " bytes at with address " PTR_FORMAT ".", size, requested_addr);
1965     } else {
1966       trcVerbose("failed to shm-allocate " UINTX_FORMAT " bytes at any address.", size);
1967     }
1968   }
1969 
1970   // book-keeping
1971   vmembk_add(addr, size, real_pagesize, VMEM_SHMATED);
1972   assert0(is_aligned_to(addr, os::vm_page_size()));
1973 
1974   return addr;
1975 }
1976 
1977 static bool release_shmated_memory(char* addr, size_t size) {
1978 
1979   trcVerbose("release_shmated_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
1980     addr, addr + size - 1);
1981 
1982   bool rc = false;
1983 
1984   // TODO: is there a way to verify shm size without doing bookkeeping?
1985   if (::shmdt(addr) != 0) {
1986     trcVerbose("error (%d).", errno);
1987   } else {
1988     trcVerbose("ok.");
1989     rc = true;
1990   }
1991   return rc;
1992 }
1993 
1994 static bool uncommit_shmated_memory(char* addr, size_t size) {
1995   trcVerbose("uncommit_shmated_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
1996     addr, addr + size - 1);
1997 
1998   const bool rc = my_disclaim64(addr, size);
1999 
2000   if (!rc) {
2001     trcVerbose("my_disclaim64(" PTR_FORMAT ", " UINTX_FORMAT ") failed.\n", addr, size);
2002     return false;
2003   }
2004   return true;
2005 }
2006 
2007 ////////////////////////////////  mmap-based routines /////////////////////////////////
2008 
2009 // Reserve memory via mmap.
2010 // If <requested_addr> is given, an attempt is made to attach at the given address.
2011 // Failing that, memory is allocated at any address.
2012 // If <alignment_hint> is given and <requested_addr> is NULL, an attempt is made to
2013 // allocate at an address aligned with the given alignment. Failing that, memory
2014 // is aligned anywhere.
2015 static char* reserve_mmaped_memory(size_t bytes, char* requested_addr, size_t alignment_hint) {
2016   trcVerbose("reserve_mmaped_memory " UINTX_FORMAT " bytes, wishaddress " PTR_FORMAT ", "
2017     "alignment_hint " UINTX_FORMAT "...",
2018     bytes, requested_addr, alignment_hint);
2019 
2020   // If a wish address is given, but not aligned to 4K page boundary, mmap will fail.
2021   if (requested_addr && !is_aligned_to(requested_addr, os::vm_page_size()) != 0) {
2022     trcVerbose("Wish address " PTR_FORMAT " not aligned to page boundary.", requested_addr);
2023     return NULL;
2024   }
2025 
2026   // We must prevent anyone from attaching too close to the
2027   // BRK because that may cause malloc OOM.
2028   if (requested_addr != NULL && is_close_to_brk((address)requested_addr)) {
2029     trcVerbose("Wish address " PTR_FORMAT " is too close to the BRK segment. "
2030       "Will attach anywhere.", requested_addr);
2031     // Act like the OS refused to attach there.
2032     requested_addr = NULL;
2033   }
2034 
2035   // Specify one or the other but not both.
2036   assert0(!(requested_addr != NULL && alignment_hint > 0));
2037 
2038   // In 64K mode, we claim the global page size (os::vm_page_size())
2039   // is 64K. This is one of the few points where that illusion may
2040   // break, because mmap() will always return memory aligned to 4K. So
2041   // we must ensure we only ever return memory aligned to 64k.
2042   if (alignment_hint) {
2043     alignment_hint = lcm(alignment_hint, os::vm_page_size());
2044   } else {
2045     alignment_hint = os::vm_page_size();
2046   }
2047 
2048   // Size shall always be a multiple of os::vm_page_size (esp. in 64K mode).
2049   const size_t size = align_up(bytes, os::vm_page_size());
2050 
2051   // alignment: Allocate memory large enough to include an aligned range of the right size and
2052   // cut off the leading and trailing waste pages.
2053   assert0(alignment_hint != 0 && is_aligned_to(alignment_hint, os::vm_page_size())); // see above
2054   const size_t extra_size = size + alignment_hint;
2055 
2056   // Note: MAP_SHARED (instead of MAP_PRIVATE) needed to be able to
2057   // later use msync(MS_INVALIDATE) (see os::uncommit_memory).
2058   int flags = MAP_ANONYMOUS | MAP_SHARED;
2059 
2060   // MAP_FIXED is needed to enforce requested_addr - manpage is vague about what
2061   // it means if wishaddress is given but MAP_FIXED is not set.
2062   //
2063   // Important! Behaviour differs depending on whether SPEC1170 mode is active or not.
2064   // SPEC1170 mode active: behaviour like POSIX, MAP_FIXED will clobber existing mappings.
2065   // SPEC1170 mode not active: behaviour, unlike POSIX, is that no existing mappings will
2066   // get clobbered.
2067   if (requested_addr != NULL) {
2068     if (!os::Aix::xpg_sus_mode()) {  // not SPEC1170 Behaviour
2069       flags |= MAP_FIXED;
2070     }
2071   }
2072 
2073   char* addr = (char*)::mmap(requested_addr, extra_size,
2074       PROT_READ|PROT_WRITE|PROT_EXEC, flags, -1, 0);
2075 
2076   if (addr == MAP_FAILED) {
2077     trcVerbose("mmap(" PTR_FORMAT ", " UINTX_FORMAT ", ..) failed (%d)", requested_addr, size, errno);
2078     return NULL;
2079   }
2080 
2081   // Handle alignment.
2082   char* const addr_aligned = align_up(addr, alignment_hint);
2083   const size_t waste_pre = addr_aligned - addr;
2084   char* const addr_aligned_end = addr_aligned + size;
2085   const size_t waste_post = extra_size - waste_pre - size;
2086   if (waste_pre > 0) {
2087     ::munmap(addr, waste_pre);
2088   }
2089   if (waste_post > 0) {
2090     ::munmap(addr_aligned_end, waste_post);
2091   }
2092   addr = addr_aligned;
2093 
2094   if (addr) {
2095     trcVerbose("mmap-allocated " PTR_FORMAT " .. " PTR_FORMAT " (" UINTX_FORMAT " bytes)",
2096       addr, addr + bytes, bytes);
2097   } else {
2098     if (requested_addr != NULL) {
2099       trcVerbose("failed to mmap-allocate " UINTX_FORMAT " bytes at wish address " PTR_FORMAT ".", bytes, requested_addr);
2100     } else {
2101       trcVerbose("failed to mmap-allocate " UINTX_FORMAT " bytes at any address.", bytes);
2102     }
2103   }
2104 
2105   // bookkeeping
2106   vmembk_add(addr, size, 4*K, VMEM_MAPPED);
2107 
2108   // Test alignment, see above.
2109   assert0(is_aligned_to(addr, os::vm_page_size()));
2110 
2111   return addr;
2112 }
2113 
2114 static bool release_mmaped_memory(char* addr, size_t size) {
2115   assert0(is_aligned_to(addr, os::vm_page_size()));
2116   assert0(is_aligned_to(size, os::vm_page_size()));
2117 
2118   trcVerbose("release_mmaped_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2119     addr, addr + size - 1);
2120   bool rc = false;
2121 
2122   if (::munmap(addr, size) != 0) {
2123     trcVerbose("failed (%d)\n", errno);
2124     rc = false;
2125   } else {
2126     trcVerbose("ok.");
2127     rc = true;
2128   }
2129 
2130   return rc;
2131 }
2132 
2133 static bool uncommit_mmaped_memory(char* addr, size_t size) {
2134 
2135   assert0(is_aligned_to(addr, os::vm_page_size()));
2136   assert0(is_aligned_to(size, os::vm_page_size()));
2137 
2138   trcVerbose("uncommit_mmaped_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2139     addr, addr + size - 1);
2140   bool rc = false;
2141 
2142   // Uncommit mmap memory with msync MS_INVALIDATE.
2143   if (::msync(addr, size, MS_INVALIDATE) != 0) {
2144     trcVerbose("failed (%d)\n", errno);
2145     rc = false;
2146   } else {
2147     trcVerbose("ok.");
2148     rc = true;
2149   }
2150 
2151   return rc;
2152 }
2153 
2154 int os::vm_page_size() {
2155   // Seems redundant as all get out.
2156   assert(os::Aix::page_size() != -1, "must call os::init");
2157   return os::Aix::page_size();
2158 }
2159 
2160 // Aix allocates memory by pages.
2161 int os::vm_allocation_granularity() {
2162   assert(os::Aix::page_size() != -1, "must call os::init");
2163   return os::Aix::page_size();
2164 }
2165 
2166 #ifdef PRODUCT
2167 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2168                                     int err) {
2169   warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2170           ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2171           os::errno_name(err), err);
2172 }
2173 #endif
2174 
2175 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2176                                   const char* mesg) {
2177   assert(mesg != NULL, "mesg must be specified");
2178   if (!pd_commit_memory(addr, size, exec)) {
2179     // Add extra info in product mode for vm_exit_out_of_memory():
2180     PRODUCT_ONLY(warn_fail_commit_memory(addr, size, exec, errno);)
2181     vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2182   }
2183 }
2184 
2185 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2186 
2187   assert(is_aligned_to(addr, os::vm_page_size()),
2188     "addr " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2189     p2i(addr), os::vm_page_size());
2190   assert(is_aligned_to(size, os::vm_page_size()),
2191     "size " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2192     size, os::vm_page_size());
2193 
2194   vmembk_t* const vmi = vmembk_find(addr);
2195   guarantee0(vmi);
2196   vmi->assert_is_valid_subrange(addr, size);
2197 
2198   trcVerbose("commit_memory [" PTR_FORMAT " - " PTR_FORMAT "].", addr, addr + size - 1);
2199 
2200   if (UseExplicitCommit) {
2201     // AIX commits memory on touch. So, touch all pages to be committed.
2202     for (char* p = addr; p < (addr + size); p += 4*K) {
2203       *p = '\0';
2204     }
2205   }
2206 
2207   return true;
2208 }
2209 
2210 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, bool exec) {
2211   return pd_commit_memory(addr, size, exec);
2212 }
2213 
2214 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2215                                   size_t alignment_hint, bool exec,
2216                                   const char* mesg) {
2217   // Alignment_hint is ignored on this OS.
2218   pd_commit_memory_or_exit(addr, size, exec, mesg);
2219 }
2220 
2221 bool os::pd_uncommit_memory(char* addr, size_t size) {
2222   assert(is_aligned_to(addr, os::vm_page_size()),
2223     "addr " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2224     p2i(addr), os::vm_page_size());
2225   assert(is_aligned_to(size, os::vm_page_size()),
2226     "size " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2227     size, os::vm_page_size());
2228 
2229   // Dynamically do different things for mmap/shmat.
2230   const vmembk_t* const vmi = vmembk_find(addr);
2231   guarantee0(vmi);
2232   vmi->assert_is_valid_subrange(addr, size);
2233 
2234   if (vmi->type == VMEM_SHMATED) {
2235     return uncommit_shmated_memory(addr, size);
2236   } else {
2237     return uncommit_mmaped_memory(addr, size);
2238   }
2239 }
2240 
2241 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2242   // Do not call this; no need to commit stack pages on AIX.
2243   ShouldNotReachHere();
2244   return true;
2245 }
2246 
2247 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2248   // Do not call this; no need to commit stack pages on AIX.
2249   ShouldNotReachHere();
2250   return true;
2251 }
2252 
2253 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2254 }
2255 
2256 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2257 }
2258 
2259 void os::numa_make_global(char *addr, size_t bytes) {
2260 }
2261 
2262 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2263 }
2264 
2265 bool os::numa_topology_changed() {
2266   return false;
2267 }
2268 
2269 size_t os::numa_get_groups_num() {
2270   return 1;
2271 }
2272 
2273 int os::numa_get_group_id() {
2274   return 0;
2275 }
2276 
2277 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2278   if (size > 0) {
2279     ids[0] = 0;
2280     return 1;
2281   }
2282   return 0;
2283 }
2284 
2285 bool os::get_page_info(char *start, page_info* info) {
2286   return false;
2287 }
2288 
2289 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2290   return end;
2291 }
2292 
2293 // Reserves and attaches a shared memory segment.
2294 // Will assert if a wish address is given and could not be obtained.
2295 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, size_t alignment_hint) {
2296 
2297   // All other Unices do a mmap(MAP_FIXED) if the addr is given,
2298   // thereby clobbering old mappings at that place. That is probably
2299   // not intended, never used and almost certainly an error were it
2300   // ever be used this way (to try attaching at a specified address
2301   // without clobbering old mappings an alternate API exists,
2302   // os::attempt_reserve_memory_at()).
2303   // Instead of mimicking the dangerous coding of the other platforms, here I
2304   // just ignore the request address (release) or assert(debug).
2305   assert0(requested_addr == NULL);
2306 
2307   // Always round to os::vm_page_size(), which may be larger than 4K.
2308   bytes = align_up(bytes, os::vm_page_size());
2309   const size_t alignment_hint0 =
2310     alignment_hint ? align_up(alignment_hint, os::vm_page_size()) : 0;
2311 
2312   // In 4K mode always use mmap.
2313   // In 64K mode allocate small sizes with mmap, large ones with 64K shmatted.
2314   if (os::vm_page_size() == 4*K) {
2315     return reserve_mmaped_memory(bytes, requested_addr, alignment_hint);
2316   } else {
2317     if (bytes >= Use64KPagesThreshold) {
2318       return reserve_shmated_memory(bytes, requested_addr, alignment_hint);
2319     } else {
2320       return reserve_mmaped_memory(bytes, requested_addr, alignment_hint);
2321     }
2322   }
2323 }
2324 
2325 bool os::pd_release_memory(char* addr, size_t size) {
2326 
2327   // Dynamically do different things for mmap/shmat.
2328   vmembk_t* const vmi = vmembk_find(addr);
2329   guarantee0(vmi);
2330 
2331   // Always round to os::vm_page_size(), which may be larger than 4K.
2332   size = align_up(size, os::vm_page_size());
2333   addr = align_up(addr, os::vm_page_size());
2334 
2335   bool rc = false;
2336   bool remove_bookkeeping = false;
2337   if (vmi->type == VMEM_SHMATED) {
2338     // For shmatted memory, we do:
2339     // - If user wants to release the whole range, release the memory (shmdt).
2340     // - If user only wants to release a partial range, uncommit (disclaim) that
2341     //   range. That way, at least, we do not use memory anymore (bust still page
2342     //   table space).
2343     vmi->assert_is_valid_subrange(addr, size);
2344     if (addr == vmi->addr && size == vmi->size) {
2345       rc = release_shmated_memory(addr, size);
2346       remove_bookkeeping = true;
2347     } else {
2348       rc = uncommit_shmated_memory(addr, size);
2349     }
2350   } else {
2351     // User may unmap partial regions but region has to be fully contained.
2352 #ifdef ASSERT
2353     vmi->assert_is_valid_subrange(addr, size);
2354 #endif
2355     rc = release_mmaped_memory(addr, size);
2356     remove_bookkeeping = true;
2357   }
2358 
2359   // update bookkeeping
2360   if (rc && remove_bookkeeping) {
2361     vmembk_remove(vmi);
2362   }
2363 
2364   return rc;
2365 }
2366 
2367 static bool checked_mprotect(char* addr, size_t size, int prot) {
2368 
2369   // Little problem here: if SPEC1170 behaviour is off, mprotect() on AIX will
2370   // not tell me if protection failed when trying to protect an un-protectable range.
2371   //
2372   // This means if the memory was allocated using shmget/shmat, protection wont work
2373   // but mprotect will still return 0:
2374   //
2375   // See http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.basetechref/doc/basetrf1/mprotect.htm
2376 
2377   bool rc = ::mprotect(addr, size, prot) == 0 ? true : false;
2378 
2379   if (!rc) {
2380     const char* const s_errno = os::errno_name(errno);
2381     warning("mprotect(" PTR_FORMAT "-" PTR_FORMAT ", 0x%X) failed (%s).", addr, addr + size, prot, s_errno);
2382     return false;
2383   }
2384 
2385   // mprotect success check
2386   //
2387   // Mprotect said it changed the protection but can I believe it?
2388   //
2389   // To be sure I need to check the protection afterwards. Try to
2390   // read from protected memory and check whether that causes a segfault.
2391   //
2392   if (!os::Aix::xpg_sus_mode()) {
2393 
2394     if (CanUseSafeFetch32()) {
2395 
2396       const bool read_protected =
2397         (SafeFetch32((int*)addr, 0x12345678) == 0x12345678 &&
2398          SafeFetch32((int*)addr, 0x76543210) == 0x76543210) ? true : false;
2399 
2400       if (prot & PROT_READ) {
2401         rc = !read_protected;
2402       } else {
2403         rc = read_protected;
2404       }
2405 
2406       if (!rc) {
2407         if (os::Aix::on_pase()) {
2408           // There is an issue on older PASE systems where mprotect() will return success but the
2409           // memory will not be protected.
2410           // This has nothing to do with the problem of using mproect() on SPEC1170 incompatible
2411           // machines; we only see it rarely, when using mprotect() to protect the guard page of
2412           // a stack. It is an OS error.
2413           //
2414           // A valid strategy is just to try again. This usually works. :-/
2415 
2416           ::usleep(1000);
2417           if (::mprotect(addr, size, prot) == 0) {
2418             const bool read_protected_2 =
2419               (SafeFetch32((int*)addr, 0x12345678) == 0x12345678 &&
2420               SafeFetch32((int*)addr, 0x76543210) == 0x76543210) ? true : false;
2421             rc = true;
2422           }
2423         }
2424       }
2425     }
2426   }
2427 
2428   assert(rc == true, "mprotect failed.");
2429 
2430   return rc;
2431 }
2432 
2433 // Set protections specified
2434 bool os::protect_memory(char* addr, size_t size, ProtType prot, bool is_committed) {
2435   unsigned int p = 0;
2436   switch (prot) {
2437   case MEM_PROT_NONE: p = PROT_NONE; break;
2438   case MEM_PROT_READ: p = PROT_READ; break;
2439   case MEM_PROT_RW:   p = PROT_READ|PROT_WRITE; break;
2440   case MEM_PROT_RWX:  p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2441   default:
2442     ShouldNotReachHere();
2443   }
2444   // is_committed is unused.
2445   return checked_mprotect(addr, size, p);
2446 }
2447 
2448 bool os::guard_memory(char* addr, size_t size) {
2449   return checked_mprotect(addr, size, PROT_NONE);
2450 }
2451 
2452 bool os::unguard_memory(char* addr, size_t size) {
2453   return checked_mprotect(addr, size, PROT_READ|PROT_WRITE|PROT_EXEC);
2454 }
2455 
2456 // Large page support
2457 
2458 static size_t _large_page_size = 0;
2459 
2460 // Enable large page support if OS allows that.
2461 void os::large_page_init() {
2462   return; // Nothing to do. See query_multipage_support and friends.
2463 }
2464 
2465 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
2466   // reserve_memory_special() is used to allocate large paged memory. On AIX, we implement
2467   // 64k paged memory reservation using the normal memory allocation paths (os::reserve_memory()),
2468   // so this is not needed.
2469   assert(false, "should not be called on AIX");
2470   return NULL;
2471 }
2472 
2473 bool os::release_memory_special(char* base, size_t bytes) {
2474   // Detaching the SHM segment will also delete it, see reserve_memory_special().
2475   Unimplemented();
2476   return false;
2477 }
2478 
2479 size_t os::large_page_size() {
2480   return _large_page_size;
2481 }
2482 
2483 bool os::can_commit_large_page_memory() {
2484   // Does not matter, we do not support huge pages.
2485   return false;
2486 }
2487 
2488 bool os::can_execute_large_page_memory() {
2489   // Does not matter, we do not support huge pages.
2490   return false;
2491 }
2492 
2493 // Reserve memory at an arbitrary address, only if that area is
2494 // available (and not reserved for something else).
2495 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
2496   char* addr = NULL;
2497 
2498   // Always round to os::vm_page_size(), which may be larger than 4K.
2499   bytes = align_up(bytes, os::vm_page_size());
2500 
2501   // In 4K mode always use mmap.
2502   // In 64K mode allocate small sizes with mmap, large ones with 64K shmatted.
2503   if (os::vm_page_size() == 4*K) {
2504     return reserve_mmaped_memory(bytes, requested_addr, 0);
2505   } else {
2506     if (bytes >= Use64KPagesThreshold) {
2507       return reserve_shmated_memory(bytes, requested_addr, 0);
2508     } else {
2509       return reserve_mmaped_memory(bytes, requested_addr, 0);
2510     }
2511   }
2512 
2513   return addr;
2514 }
2515 
2516 size_t os::read(int fd, void *buf, unsigned int nBytes) {
2517   return ::read(fd, buf, nBytes);
2518 }
2519 
2520 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
2521   return ::pread(fd, buf, nBytes, offset);
2522 }
2523 
2524 void os::naked_short_sleep(jlong ms) {
2525   struct timespec req;
2526 
2527   assert(ms < 1000, "Un-interruptable sleep, short time use only");
2528   req.tv_sec = 0;
2529   if (ms > 0) {
2530     req.tv_nsec = (ms % 1000) * 1000000;
2531   }
2532   else {
2533     req.tv_nsec = 1;
2534   }
2535 
2536   nanosleep(&req, NULL);
2537 
2538   return;
2539 }
2540 
2541 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
2542 void os::infinite_sleep() {
2543   while (true) {    // sleep forever ...
2544     ::sleep(100);   // ... 100 seconds at a time
2545   }
2546 }
2547 
2548 // Used to convert frequent JVM_Yield() to nops
2549 bool os::dont_yield() {
2550   return DontYieldALot;
2551 }
2552 
2553 void os::naked_yield() {
2554   sched_yield();
2555 }
2556 
2557 ////////////////////////////////////////////////////////////////////////////////
2558 // thread priority support
2559 
2560 // From AIX manpage to pthread_setschedparam
2561 // (see: http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?
2562 //    topic=/com.ibm.aix.basetechref/doc/basetrf1/pthread_setschedparam.htm):
2563 //
2564 // "If schedpolicy is SCHED_OTHER, then sched_priority must be in the
2565 // range from 40 to 80, where 40 is the least favored priority and 80
2566 // is the most favored."
2567 //
2568 // (Actually, I doubt this even has an impact on AIX, as we do kernel
2569 // scheduling there; however, this still leaves iSeries.)
2570 //
2571 // We use the same values for AIX and PASE.
2572 int os::java_to_os_priority[CriticalPriority + 1] = {
2573   54,             // 0 Entry should never be used
2574 
2575   55,             // 1 MinPriority
2576   55,             // 2
2577   56,             // 3
2578 
2579   56,             // 4
2580   57,             // 5 NormPriority
2581   57,             // 6
2582 
2583   58,             // 7
2584   58,             // 8
2585   59,             // 9 NearMaxPriority
2586 
2587   60,             // 10 MaxPriority
2588 
2589   60              // 11 CriticalPriority
2590 };
2591 
2592 OSReturn os::set_native_priority(Thread* thread, int newpri) {
2593   if (!UseThreadPriorities) return OS_OK;
2594   pthread_t thr = thread->osthread()->pthread_id();
2595   int policy = SCHED_OTHER;
2596   struct sched_param param;
2597   param.sched_priority = newpri;
2598   int ret = pthread_setschedparam(thr, policy, &param);
2599 
2600   if (ret != 0) {
2601     trcVerbose("Could not change priority for thread %d to %d (error %d, %s)",
2602         (int)thr, newpri, ret, os::errno_name(ret));
2603   }
2604   return (ret == 0) ? OS_OK : OS_ERR;
2605 }
2606 
2607 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
2608   if (!UseThreadPriorities) {
2609     *priority_ptr = java_to_os_priority[NormPriority];
2610     return OS_OK;
2611   }
2612   pthread_t thr = thread->osthread()->pthread_id();
2613   int policy = SCHED_OTHER;
2614   struct sched_param param;
2615   int ret = pthread_getschedparam(thr, &policy, &param);
2616   *priority_ptr = param.sched_priority;
2617 
2618   return (ret == 0) ? OS_OK : OS_ERR;
2619 }
2620 
2621 // Hint to the underlying OS that a task switch would not be good.
2622 // Void return because it's a hint and can fail.
2623 void os::hint_no_preempt() {}
2624 
2625 ////////////////////////////////////////////////////////////////////////////////
2626 // suspend/resume support
2627 
2628 //  The low-level signal-based suspend/resume support is a remnant from the
2629 //  old VM-suspension that used to be for java-suspension, safepoints etc,
2630 //  within hotspot. Currently used by JFR's OSThreadSampler
2631 //
2632 //  The remaining code is greatly simplified from the more general suspension
2633 //  code that used to be used.
2634 //
2635 //  The protocol is quite simple:
2636 //  - suspend:
2637 //      - sends a signal to the target thread
2638 //      - polls the suspend state of the osthread using a yield loop
2639 //      - target thread signal handler (SR_handler) sets suspend state
2640 //        and blocks in sigsuspend until continued
2641 //  - resume:
2642 //      - sets target osthread state to continue
2643 //      - sends signal to end the sigsuspend loop in the SR_handler
2644 //
2645 //  Note that the SR_lock plays no role in this suspend/resume protocol,
2646 //  but is checked for NULL in SR_handler as a thread termination indicator.
2647 //  The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
2648 //
2649 //  Note that resume_clear_context() and suspend_save_context() are needed
2650 //  by SR_handler(), so that fetch_frame_from_ucontext() works,
2651 //  which in part is used by:
2652 //    - Forte Analyzer: AsyncGetCallTrace()
2653 //    - StackBanging: get_frame_at_stack_banging_point()
2654 
2655 static void resume_clear_context(OSThread *osthread) {
2656   osthread->set_ucontext(NULL);
2657   osthread->set_siginfo(NULL);
2658 }
2659 
2660 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
2661   osthread->set_ucontext(context);
2662   osthread->set_siginfo(siginfo);
2663 }
2664 
2665 //
2666 // Handler function invoked when a thread's execution is suspended or
2667 // resumed. We have to be careful that only async-safe functions are
2668 // called here (Note: most pthread functions are not async safe and
2669 // should be avoided.)
2670 //
2671 // Note: sigwait() is a more natural fit than sigsuspend() from an
2672 // interface point of view, but sigwait() prevents the signal hander
2673 // from being run. libpthread would get very confused by not having
2674 // its signal handlers run and prevents sigwait()'s use with the
2675 // mutex granting granting signal.
2676 //
2677 // Currently only ever called on the VMThread and JavaThreads (PC sampling).
2678 //
2679 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
2680   // Save and restore errno to avoid confusing native code with EINTR
2681   // after sigsuspend.
2682   int old_errno = errno;
2683 
2684   Thread* thread = Thread::current_or_null_safe();
2685   assert(thread != NULL, "Missing current thread in SR_handler");
2686 
2687   // On some systems we have seen signal delivery get "stuck" until the signal
2688   // mask is changed as part of thread termination. Check that the current thread
2689   // has not already terminated (via SR_lock()) - else the following assertion
2690   // will fail because the thread is no longer a JavaThread as the ~JavaThread
2691   // destructor has completed.
2692 
2693   if (thread->SR_lock() == NULL) {
2694     return;
2695   }
2696 
2697   assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
2698 
2699   OSThread* osthread = thread->osthread();
2700 
2701   os::SuspendResume::State current = osthread->sr.state();
2702   if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
2703     suspend_save_context(osthread, siginfo, context);
2704 
2705     // attempt to switch the state, we assume we had a SUSPEND_REQUEST
2706     os::SuspendResume::State state = osthread->sr.suspended();
2707     if (state == os::SuspendResume::SR_SUSPENDED) {
2708       sigset_t suspend_set;  // signals for sigsuspend()
2709 
2710       // get current set of blocked signals and unblock resume signal
2711       pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
2712       sigdelset(&suspend_set, SR_signum);
2713 
2714       // wait here until we are resumed
2715       while (1) {
2716         sigsuspend(&suspend_set);
2717 
2718         os::SuspendResume::State result = osthread->sr.running();
2719         if (result == os::SuspendResume::SR_RUNNING) {
2720           break;
2721         }
2722       }
2723 
2724     } else if (state == os::SuspendResume::SR_RUNNING) {
2725       // request was cancelled, continue
2726     } else {
2727       ShouldNotReachHere();
2728     }
2729 
2730     resume_clear_context(osthread);
2731   } else if (current == os::SuspendResume::SR_RUNNING) {
2732     // request was cancelled, continue
2733   } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
2734     // ignore
2735   } else {
2736     ShouldNotReachHere();
2737   }
2738 
2739   errno = old_errno;
2740 }
2741 
2742 static int SR_initialize() {
2743   struct sigaction act;
2744   char *s;
2745   // Get signal number to use for suspend/resume
2746   if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
2747     int sig = ::strtol(s, 0, 10);
2748     if (sig > MAX2(SIGSEGV, SIGBUS) &&  // See 4355769.
2749         sig < NSIG) {                   // Must be legal signal and fit into sigflags[].
2750       SR_signum = sig;
2751     } else {
2752       warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
2753               sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
2754     }
2755   }
2756 
2757   assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
2758         "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
2759 
2760   sigemptyset(&SR_sigset);
2761   sigaddset(&SR_sigset, SR_signum);
2762 
2763   // Set up signal handler for suspend/resume.
2764   act.sa_flags = SA_RESTART|SA_SIGINFO;
2765   act.sa_handler = (void (*)(int)) SR_handler;
2766 
2767   // SR_signum is blocked by default.
2768   pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
2769 
2770   if (sigaction(SR_signum, &act, 0) == -1) {
2771     return -1;
2772   }
2773 
2774   // Save signal flag
2775   os::Aix::set_our_sigflags(SR_signum, act.sa_flags);
2776   return 0;
2777 }
2778 
2779 static int SR_finalize() {
2780   return 0;
2781 }
2782 
2783 static int sr_notify(OSThread* osthread) {
2784   int status = pthread_kill(osthread->pthread_id(), SR_signum);
2785   assert_status(status == 0, status, "pthread_kill");
2786   return status;
2787 }
2788 
2789 // "Randomly" selected value for how long we want to spin
2790 // before bailing out on suspending a thread, also how often
2791 // we send a signal to a thread we want to resume
2792 static const int RANDOMLY_LARGE_INTEGER = 1000000;
2793 static const int RANDOMLY_LARGE_INTEGER2 = 100;
2794 
2795 // returns true on success and false on error - really an error is fatal
2796 // but this seems the normal response to library errors
2797 static bool do_suspend(OSThread* osthread) {
2798   assert(osthread->sr.is_running(), "thread should be running");
2799   // mark as suspended and send signal
2800 
2801   if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
2802     // failed to switch, state wasn't running?
2803     ShouldNotReachHere();
2804     return false;
2805   }
2806 
2807   if (sr_notify(osthread) != 0) {
2808     // try to cancel, switch to running
2809 
2810     os::SuspendResume::State result = osthread->sr.cancel_suspend();
2811     if (result == os::SuspendResume::SR_RUNNING) {
2812       // cancelled
2813       return false;
2814     } else if (result == os::SuspendResume::SR_SUSPENDED) {
2815       // somehow managed to suspend
2816       return true;
2817     } else {
2818       ShouldNotReachHere();
2819       return false;
2820     }
2821   }
2822 
2823   // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
2824 
2825   for (int n = 0; !osthread->sr.is_suspended(); n++) {
2826     for (int i = 0; i < RANDOMLY_LARGE_INTEGER2 && !osthread->sr.is_suspended(); i++) {
2827       os::naked_yield();
2828     }
2829 
2830     // timeout, try to cancel the request
2831     if (n >= RANDOMLY_LARGE_INTEGER) {
2832       os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
2833       if (cancelled == os::SuspendResume::SR_RUNNING) {
2834         return false;
2835       } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
2836         return true;
2837       } else {
2838         ShouldNotReachHere();
2839         return false;
2840       }
2841     }
2842   }
2843 
2844   guarantee(osthread->sr.is_suspended(), "Must be suspended");
2845   return true;
2846 }
2847 
2848 static void do_resume(OSThread* osthread) {
2849   //assert(osthread->sr.is_suspended(), "thread should be suspended");
2850 
2851   if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
2852     // failed to switch to WAKEUP_REQUEST
2853     ShouldNotReachHere();
2854     return;
2855   }
2856 
2857   while (!osthread->sr.is_running()) {
2858     if (sr_notify(osthread) == 0) {
2859       for (int n = 0; n < RANDOMLY_LARGE_INTEGER && !osthread->sr.is_running(); n++) {
2860         for (int i = 0; i < 100 && !osthread->sr.is_running(); i++) {
2861           os::naked_yield();
2862         }
2863       }
2864     } else {
2865       ShouldNotReachHere();
2866     }
2867   }
2868 
2869   guarantee(osthread->sr.is_running(), "Must be running!");
2870 }
2871 
2872 ///////////////////////////////////////////////////////////////////////////////////
2873 // signal handling (except suspend/resume)
2874 
2875 // This routine may be used by user applications as a "hook" to catch signals.
2876 // The user-defined signal handler must pass unrecognized signals to this
2877 // routine, and if it returns true (non-zero), then the signal handler must
2878 // return immediately. If the flag "abort_if_unrecognized" is true, then this
2879 // routine will never retun false (zero), but instead will execute a VM panic
2880 // routine kill the process.
2881 //
2882 // If this routine returns false, it is OK to call it again. This allows
2883 // the user-defined signal handler to perform checks either before or after
2884 // the VM performs its own checks. Naturally, the user code would be making
2885 // a serious error if it tried to handle an exception (such as a null check
2886 // or breakpoint) that the VM was generating for its own correct operation.
2887 //
2888 // This routine may recognize any of the following kinds of signals:
2889 //   SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
2890 // It should be consulted by handlers for any of those signals.
2891 //
2892 // The caller of this routine must pass in the three arguments supplied
2893 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
2894 // field of the structure passed to sigaction(). This routine assumes that
2895 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
2896 //
2897 // Note that the VM will print warnings if it detects conflicting signal
2898 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
2899 //
2900 extern "C" JNIEXPORT int
2901 JVM_handle_aix_signal(int signo, siginfo_t* siginfo, void* ucontext, int abort_if_unrecognized);
2902 
2903 // Set thread signal mask (for some reason on AIX sigthreadmask() seems
2904 // to be the thing to call; documentation is not terribly clear about whether
2905 // pthread_sigmask also works, and if it does, whether it does the same.
2906 bool set_thread_signal_mask(int how, const sigset_t* set, sigset_t* oset) {
2907   const int rc = ::pthread_sigmask(how, set, oset);
2908   // return value semantics differ slightly for error case:
2909   // pthread_sigmask returns error number, sigthreadmask -1 and sets global errno
2910   // (so, pthread_sigmask is more theadsafe for error handling)
2911   // But success is always 0.
2912   return rc == 0 ? true : false;
2913 }
2914 
2915 // Function to unblock all signals which are, according
2916 // to POSIX, typical program error signals. If they happen while being blocked,
2917 // they typically will bring down the process immediately.
2918 bool unblock_program_error_signals() {
2919   sigset_t set;
2920   ::sigemptyset(&set);
2921   ::sigaddset(&set, SIGILL);
2922   ::sigaddset(&set, SIGBUS);
2923   ::sigaddset(&set, SIGFPE);
2924   ::sigaddset(&set, SIGSEGV);
2925   return set_thread_signal_mask(SIG_UNBLOCK, &set, NULL);
2926 }
2927 
2928 // Renamed from 'signalHandler' to avoid collision with other shared libs.
2929 void javaSignalHandler(int sig, siginfo_t* info, void* uc) {
2930   assert(info != NULL && uc != NULL, "it must be old kernel");
2931 
2932   // Never leave program error signals blocked;
2933   // on all our platforms they would bring down the process immediately when
2934   // getting raised while being blocked.
2935   unblock_program_error_signals();
2936 
2937   int orig_errno = errno;  // Preserve errno value over signal handler.
2938   JVM_handle_aix_signal(sig, info, uc, true);
2939   errno = orig_errno;
2940 }
2941 
2942 // This boolean allows users to forward their own non-matching signals
2943 // to JVM_handle_aix_signal, harmlessly.
2944 bool os::Aix::signal_handlers_are_installed = false;
2945 
2946 // For signal-chaining
2947 struct sigaction sigact[NSIG];
2948 sigset_t sigs;
2949 bool os::Aix::libjsig_is_loaded = false;
2950 typedef struct sigaction *(*get_signal_t)(int);
2951 get_signal_t os::Aix::get_signal_action = NULL;
2952 
2953 struct sigaction* os::Aix::get_chained_signal_action(int sig) {
2954   struct sigaction *actp = NULL;
2955 
2956   if (libjsig_is_loaded) {
2957     // Retrieve the old signal handler from libjsig
2958     actp = (*get_signal_action)(sig);
2959   }
2960   if (actp == NULL) {
2961     // Retrieve the preinstalled signal handler from jvm
2962     actp = get_preinstalled_handler(sig);
2963   }
2964 
2965   return actp;
2966 }
2967 
2968 static bool call_chained_handler(struct sigaction *actp, int sig,
2969                                  siginfo_t *siginfo, void *context) {
2970   // Call the old signal handler
2971   if (actp->sa_handler == SIG_DFL) {
2972     // It's more reasonable to let jvm treat it as an unexpected exception
2973     // instead of taking the default action.
2974     return false;
2975   } else if (actp->sa_handler != SIG_IGN) {
2976     if ((actp->sa_flags & SA_NODEFER) == 0) {
2977       // automaticlly block the signal
2978       sigaddset(&(actp->sa_mask), sig);
2979     }
2980 
2981     sa_handler_t hand = NULL;
2982     sa_sigaction_t sa = NULL;
2983     bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
2984     // retrieve the chained handler
2985     if (siginfo_flag_set) {
2986       sa = actp->sa_sigaction;
2987     } else {
2988       hand = actp->sa_handler;
2989     }
2990 
2991     if ((actp->sa_flags & SA_RESETHAND) != 0) {
2992       actp->sa_handler = SIG_DFL;
2993     }
2994 
2995     // try to honor the signal mask
2996     sigset_t oset;
2997     pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
2998 
2999     // call into the chained handler
3000     if (siginfo_flag_set) {
3001       (*sa)(sig, siginfo, context);
3002     } else {
3003       (*hand)(sig);
3004     }
3005 
3006     // restore the signal mask
3007     pthread_sigmask(SIG_SETMASK, &oset, 0);
3008   }
3009   // Tell jvm's signal handler the signal is taken care of.
3010   return true;
3011 }
3012 
3013 bool os::Aix::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3014   bool chained = false;
3015   // signal-chaining
3016   if (UseSignalChaining) {
3017     struct sigaction *actp = get_chained_signal_action(sig);
3018     if (actp != NULL) {
3019       chained = call_chained_handler(actp, sig, siginfo, context);
3020     }
3021   }
3022   return chained;
3023 }
3024 
3025 struct sigaction* os::Aix::get_preinstalled_handler(int sig) {
3026   if (sigismember(&sigs, sig)) {
3027     return &sigact[sig];
3028   }
3029   return NULL;
3030 }
3031 
3032 void os::Aix::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3033   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3034   sigact[sig] = oldAct;
3035   sigaddset(&sigs, sig);
3036 }
3037 
3038 // for diagnostic
3039 int sigflags[NSIG];
3040 
3041 int os::Aix::get_our_sigflags(int sig) {
3042   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3043   return sigflags[sig];
3044 }
3045 
3046 void os::Aix::set_our_sigflags(int sig, int flags) {
3047   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3048   if (sig > 0 && sig < NSIG) {
3049     sigflags[sig] = flags;
3050   }
3051 }
3052 
3053 void os::Aix::set_signal_handler(int sig, bool set_installed) {
3054   // Check for overwrite.
3055   struct sigaction oldAct;
3056   sigaction(sig, (struct sigaction*)NULL, &oldAct);
3057 
3058   void* oldhand = oldAct.sa_sigaction
3059     ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3060     : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3061   if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3062       oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3063       oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)javaSignalHandler)) {
3064     if (AllowUserSignalHandlers || !set_installed) {
3065       // Do not overwrite; user takes responsibility to forward to us.
3066       return;
3067     } else if (UseSignalChaining) {
3068       // save the old handler in jvm
3069       save_preinstalled_handler(sig, oldAct);
3070       // libjsig also interposes the sigaction() call below and saves the
3071       // old sigaction on it own.
3072     } else {
3073       fatal("Encountered unexpected pre-existing sigaction handler "
3074             "%#lx for signal %d.", (long)oldhand, sig);
3075     }
3076   }
3077 
3078   struct sigaction sigAct;
3079   sigfillset(&(sigAct.sa_mask));
3080   if (!set_installed) {
3081     sigAct.sa_handler = SIG_DFL;
3082     sigAct.sa_flags = SA_RESTART;
3083   } else {
3084     sigAct.sa_sigaction = javaSignalHandler;
3085     sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3086   }
3087   // Save flags, which are set by ours
3088   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3089   sigflags[sig] = sigAct.sa_flags;
3090 
3091   int ret = sigaction(sig, &sigAct, &oldAct);
3092   assert(ret == 0, "check");
3093 
3094   void* oldhand2 = oldAct.sa_sigaction
3095                  ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3096                  : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3097   assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3098 }
3099 
3100 // install signal handlers for signals that HotSpot needs to
3101 // handle in order to support Java-level exception handling.
3102 void os::Aix::install_signal_handlers() {
3103   if (!signal_handlers_are_installed) {
3104     signal_handlers_are_installed = true;
3105 
3106     // signal-chaining
3107     typedef void (*signal_setting_t)();
3108     signal_setting_t begin_signal_setting = NULL;
3109     signal_setting_t end_signal_setting = NULL;
3110     begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3111                              dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3112     if (begin_signal_setting != NULL) {
3113       end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3114                              dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3115       get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3116                             dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3117       libjsig_is_loaded = true;
3118       assert(UseSignalChaining, "should enable signal-chaining");
3119     }
3120     if (libjsig_is_loaded) {
3121       // Tell libjsig jvm is setting signal handlers.
3122       (*begin_signal_setting)();
3123     }
3124 
3125     ::sigemptyset(&sigs);
3126     set_signal_handler(SIGSEGV, true);
3127     set_signal_handler(SIGPIPE, true);
3128     set_signal_handler(SIGBUS, true);
3129     set_signal_handler(SIGILL, true);
3130     set_signal_handler(SIGFPE, true);
3131     set_signal_handler(SIGTRAP, true);
3132     set_signal_handler(SIGXFSZ, true);
3133 
3134     if (libjsig_is_loaded) {
3135       // Tell libjsig jvm finishes setting signal handlers.
3136       (*end_signal_setting)();
3137     }
3138 
3139     // We don't activate signal checker if libjsig is in place, we trust ourselves
3140     // and if UserSignalHandler is installed all bets are off.
3141     // Log that signal checking is off only if -verbose:jni is specified.
3142     if (CheckJNICalls) {
3143       if (libjsig_is_loaded) {
3144         tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3145         check_signals = false;
3146       }
3147       if (AllowUserSignalHandlers) {
3148         tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3149         check_signals = false;
3150       }
3151       // Need to initialize check_signal_done.
3152       ::sigemptyset(&check_signal_done);
3153     }
3154   }
3155 }
3156 
3157 static const char* get_signal_handler_name(address handler,
3158                                            char* buf, int buflen) {
3159   int offset;
3160   bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3161   if (found) {
3162     // skip directory names
3163     const char *p1, *p2;
3164     p1 = buf;
3165     size_t len = strlen(os::file_separator());
3166     while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3167     // The way os::dll_address_to_library_name is implemented on Aix
3168     // right now, it always returns -1 for the offset which is not
3169     // terribly informative.
3170     // Will fix that. For now, omit the offset.
3171     jio_snprintf(buf, buflen, "%s", p1);
3172   } else {
3173     jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3174   }
3175   return buf;
3176 }
3177 
3178 static void print_signal_handler(outputStream* st, int sig,
3179                                  char* buf, size_t buflen) {
3180   struct sigaction sa;
3181   sigaction(sig, NULL, &sa);
3182 
3183   st->print("%s: ", os::exception_name(sig, buf, buflen));
3184 
3185   address handler = (sa.sa_flags & SA_SIGINFO)
3186     ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3187     : CAST_FROM_FN_PTR(address, sa.sa_handler);
3188 
3189   if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3190     st->print("SIG_DFL");
3191   } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3192     st->print("SIG_IGN");
3193   } else {
3194     st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3195   }
3196 
3197   // Print readable mask.
3198   st->print(", sa_mask[0]=");
3199   os::Posix::print_signal_set_short(st, &sa.sa_mask);
3200 
3201   address rh = VMError::get_resetted_sighandler(sig);
3202   // May be, handler was resetted by VMError?
3203   if (rh != NULL) {
3204     handler = rh;
3205     sa.sa_flags = VMError::get_resetted_sigflags(sig);
3206   }
3207 
3208   // Print textual representation of sa_flags.
3209   st->print(", sa_flags=");
3210   os::Posix::print_sa_flags(st, sa.sa_flags);
3211 
3212   // Check: is it our handler?
3213   if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)javaSignalHandler) ||
3214       handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3215     // It is our signal handler.
3216     // Check for flags, reset system-used one!
3217     if ((int)sa.sa_flags != os::Aix::get_our_sigflags(sig)) {
3218       st->print(", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3219                 os::Aix::get_our_sigflags(sig));
3220     }
3221   }
3222   st->cr();
3223 }
3224 
3225 #define DO_SIGNAL_CHECK(sig) \
3226   if (!sigismember(&check_signal_done, sig)) \
3227     os::Aix::check_signal_handler(sig)
3228 
3229 // This method is a periodic task to check for misbehaving JNI applications
3230 // under CheckJNI, we can add any periodic checks here
3231 
3232 void os::run_periodic_checks() {
3233 
3234   if (check_signals == false) return;
3235 
3236   // SEGV and BUS if overridden could potentially prevent
3237   // generation of hs*.log in the event of a crash, debugging
3238   // such a case can be very challenging, so we absolutely
3239   // check the following for a good measure:
3240   DO_SIGNAL_CHECK(SIGSEGV);
3241   DO_SIGNAL_CHECK(SIGILL);
3242   DO_SIGNAL_CHECK(SIGFPE);
3243   DO_SIGNAL_CHECK(SIGBUS);
3244   DO_SIGNAL_CHECK(SIGPIPE);
3245   DO_SIGNAL_CHECK(SIGXFSZ);
3246   if (UseSIGTRAP) {
3247     DO_SIGNAL_CHECK(SIGTRAP);
3248   }
3249 
3250   // ReduceSignalUsage allows the user to override these handlers
3251   // see comments at the very top and jvm_md.h
3252   if (!ReduceSignalUsage) {
3253     DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
3254     DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
3255     DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
3256     DO_SIGNAL_CHECK(BREAK_SIGNAL);
3257   }
3258 
3259   DO_SIGNAL_CHECK(SR_signum);
3260 }
3261 
3262 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
3263 
3264 static os_sigaction_t os_sigaction = NULL;
3265 
3266 void os::Aix::check_signal_handler(int sig) {
3267   char buf[O_BUFLEN];
3268   address jvmHandler = NULL;
3269 
3270   struct sigaction act;
3271   if (os_sigaction == NULL) {
3272     // only trust the default sigaction, in case it has been interposed
3273     os_sigaction = CAST_TO_FN_PTR(os_sigaction_t, dlsym(RTLD_DEFAULT, "sigaction"));
3274     if (os_sigaction == NULL) return;
3275   }
3276 
3277   os_sigaction(sig, (struct sigaction*)NULL, &act);
3278 
3279   address thisHandler = (act.sa_flags & SA_SIGINFO)
3280     ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
3281     : CAST_FROM_FN_PTR(address, act.sa_handler);
3282 
3283   switch(sig) {
3284   case SIGSEGV:
3285   case SIGBUS:
3286   case SIGFPE:
3287   case SIGPIPE:
3288   case SIGILL:
3289   case SIGXFSZ:
3290     jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)javaSignalHandler);
3291     break;
3292 
3293   case SHUTDOWN1_SIGNAL:
3294   case SHUTDOWN2_SIGNAL:
3295   case SHUTDOWN3_SIGNAL:
3296   case BREAK_SIGNAL:
3297     jvmHandler = (address)user_handler();
3298     break;
3299 
3300   default:
3301     if (sig == SR_signum) {
3302       jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
3303     } else {
3304       return;
3305     }
3306     break;
3307   }
3308 
3309   if (thisHandler != jvmHandler) {
3310     tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
3311     tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
3312     tty->print_cr("  found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
3313     // No need to check this sig any longer
3314     sigaddset(&check_signal_done, sig);
3315     // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
3316     if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
3317       tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
3318                     exception_name(sig, buf, O_BUFLEN));
3319     }
3320   } else if (os::Aix::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Aix::get_our_sigflags(sig)) {
3321     tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
3322     tty->print("expected:");
3323     os::Posix::print_sa_flags(tty, os::Aix::get_our_sigflags(sig));
3324     tty->cr();
3325     tty->print("  found:");
3326     os::Posix::print_sa_flags(tty, act.sa_flags);
3327     tty->cr();
3328     // No need to check this sig any longer
3329     sigaddset(&check_signal_done, sig);
3330   }
3331 
3332   // Dump all the signal
3333   if (sigismember(&check_signal_done, sig)) {
3334     print_signal_handlers(tty, buf, O_BUFLEN);
3335   }
3336 }
3337 
3338 // To install functions for atexit system call
3339 extern "C" {
3340   static void perfMemory_exit_helper() {
3341     perfMemory_exit();
3342   }
3343 }
3344 
3345 // This is called _before_ the most of global arguments have been parsed.
3346 void os::init(void) {
3347   // This is basic, we want to know if that ever changes.
3348   // (Shared memory boundary is supposed to be a 256M aligned.)
3349   assert(SHMLBA == ((uint64_t)0x10000000ULL)/*256M*/, "unexpected");
3350 
3351   // Record process break at startup.
3352   g_brk_at_startup = (address) ::sbrk(0);
3353   assert(g_brk_at_startup != (address) -1, "sbrk failed");
3354 
3355   // First off, we need to know whether we run on AIX or PASE, and
3356   // the OS level we run on.
3357   os::Aix::initialize_os_info();
3358 
3359   // Scan environment (SPEC1170 behaviour, etc).
3360   os::Aix::scan_environment();
3361 
3362   // Probe multipage support.
3363   query_multipage_support();
3364 
3365   // Act like we only have one page size by eliminating corner cases which
3366   // we did not support very well anyway.
3367   // We have two input conditions:
3368   // 1) Data segment page size. This is controlled by linker setting (datapsize) on the
3369   //    launcher, and/or by LDR_CNTRL environment variable. The latter overrules the linker
3370   //    setting.
3371   //    Data segment page size is important for us because it defines the thread stack page
3372   //    size, which is needed for guard page handling, stack banging etc.
3373   // 2) The ability to allocate 64k pages dynamically. If this is a given, java heap can
3374   //    and should be allocated with 64k pages.
3375   //
3376   // So, we do the following:
3377   // LDR_CNTRL    can_use_64K_pages_dynamically       what we do                      remarks
3378   // 4K           no                                  4K                              old systems (aix 5.2, as/400 v5r4) or new systems with AME activated
3379   // 4k           yes                                 64k (treat 4k stacks as 64k)    different loader than java and standard settings
3380   // 64k          no              --- AIX 5.2 ? ---
3381   // 64k          yes                                 64k                             new systems and standard java loader (we set datapsize=64k when linking)
3382 
3383   // We explicitly leave no option to change page size, because only upgrading would work,
3384   // not downgrading (if stack page size is 64k you cannot pretend its 4k).
3385 
3386   if (g_multipage_support.datapsize == 4*K) {
3387     // datapsize = 4K. Data segment, thread stacks are 4K paged.
3388     if (g_multipage_support.can_use_64K_pages) {
3389       // .. but we are able to use 64K pages dynamically.
3390       // This would be typical for java launchers which are not linked
3391       // with datapsize=64K (like, any other launcher but our own).
3392       //
3393       // In this case it would be smart to allocate the java heap with 64K
3394       // to get the performance benefit, and to fake 64k pages for the
3395       // data segment (when dealing with thread stacks).
3396       //
3397       // However, leave a possibility to downgrade to 4K, using
3398       // -XX:-Use64KPages.
3399       if (Use64KPages) {
3400         trcVerbose("64K page mode (faked for data segment)");
3401         Aix::_page_size = 64*K;
3402       } else {
3403         trcVerbose("4K page mode (Use64KPages=off)");
3404         Aix::_page_size = 4*K;
3405       }
3406     } else {
3407       // .. and not able to allocate 64k pages dynamically. Here, just
3408       // fall back to 4K paged mode and use mmap for everything.
3409       trcVerbose("4K page mode");
3410       Aix::_page_size = 4*K;
3411       FLAG_SET_ERGO(bool, Use64KPages, false);
3412     }
3413   } else {
3414     // datapsize = 64k. Data segment, thread stacks are 64k paged.
3415     // This normally means that we can allocate 64k pages dynamically.
3416     // (There is one special case where this may be false: EXTSHM=on.
3417     // but we decided to not support that mode).
3418     assert0(g_multipage_support.can_use_64K_pages);
3419     Aix::_page_size = 64*K;
3420     trcVerbose("64K page mode");
3421     FLAG_SET_ERGO(bool, Use64KPages, true);
3422   }
3423 
3424   // For now UseLargePages is just ignored.
3425   FLAG_SET_ERGO(bool, UseLargePages, false);
3426   _page_sizes[0] = 0;
3427 
3428   // debug trace
3429   trcVerbose("os::vm_page_size %s", describe_pagesize(os::vm_page_size()));
3430 
3431   // Next, we need to initialize libo4 and libperfstat libraries.
3432   if (os::Aix::on_pase()) {
3433     os::Aix::initialize_libo4();
3434   } else {
3435     os::Aix::initialize_libperfstat();
3436   }
3437 
3438   // Reset the perfstat information provided by ODM.
3439   if (os::Aix::on_aix()) {
3440     libperfstat::perfstat_reset();
3441   }
3442 
3443   // Now initialze basic system properties. Note that for some of the values we
3444   // need libperfstat etc.
3445   os::Aix::initialize_system_info();
3446 
3447   clock_tics_per_sec = sysconf(_SC_CLK_TCK);
3448 
3449   init_random(1234567);
3450 
3451   // Main_thread points to the aboriginal thread.
3452   Aix::_main_thread = pthread_self();
3453 
3454   initial_time_count = os::elapsed_counter();
3455 
3456   os::Posix::init();
3457 }
3458 
3459 // This is called _after_ the global arguments have been parsed.
3460 jint os::init_2(void) {
3461 
3462   os::Posix::init_2();
3463 
3464   if (os::Aix::on_pase()) {
3465     trcVerbose("Running on PASE.");
3466   } else {
3467     trcVerbose("Running on AIX (not PASE).");
3468   }
3469 
3470   trcVerbose("processor count: %d", os::_processor_count);
3471   trcVerbose("physical memory: %lu", Aix::_physical_memory);
3472 
3473   // Initially build up the loaded dll map.
3474   LoadedLibraries::reload();
3475   if (Verbose) {
3476     trcVerbose("Loaded Libraries: ");
3477     LoadedLibraries::print(tty);
3478   }
3479 
3480   // initialize suspend/resume support - must do this before signal_sets_init()
3481   if (SR_initialize() != 0) {
3482     perror("SR_initialize failed");
3483     return JNI_ERR;
3484   }
3485 
3486   Aix::signal_sets_init();
3487   Aix::install_signal_handlers();
3488 
3489   // Check and sets minimum stack sizes against command line options
3490   if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
3491     return JNI_ERR;
3492   }
3493 
3494   if (UseNUMA) {
3495     UseNUMA = false;
3496     warning("NUMA optimizations are not available on this OS.");
3497   }
3498 
3499   if (MaxFDLimit) {
3500     // Set the number of file descriptors to max. print out error
3501     // if getrlimit/setrlimit fails but continue regardless.
3502     struct rlimit nbr_files;
3503     int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
3504     if (status != 0) {
3505       log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
3506     } else {
3507       nbr_files.rlim_cur = nbr_files.rlim_max;
3508       status = setrlimit(RLIMIT_NOFILE, &nbr_files);
3509       if (status != 0) {
3510         log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
3511       }
3512     }
3513   }
3514 
3515   if (PerfAllowAtExitRegistration) {
3516     // Only register atexit functions if PerfAllowAtExitRegistration is set.
3517     // At exit functions can be delayed until process exit time, which
3518     // can be problematic for embedded VM situations. Embedded VMs should
3519     // call DestroyJavaVM() to assure that VM resources are released.
3520 
3521     // Note: perfMemory_exit_helper atexit function may be removed in
3522     // the future if the appropriate cleanup code can be added to the
3523     // VM_Exit VMOperation's doit method.
3524     if (atexit(perfMemory_exit_helper) != 0) {
3525       warning("os::init_2 atexit(perfMemory_exit_helper) failed");
3526     }
3527   }
3528 
3529   return JNI_OK;
3530 }
3531 
3532 // Mark the polling page as unreadable
3533 void os::make_polling_page_unreadable(void) {
3534   if (!guard_memory((char*)_polling_page, Aix::page_size())) {
3535     fatal("Could not disable polling page");
3536   }
3537 };
3538 
3539 // Mark the polling page as readable
3540 void os::make_polling_page_readable(void) {
3541   // Changed according to os_linux.cpp.
3542   if (!checked_mprotect((char *)_polling_page, Aix::page_size(), PROT_READ)) {
3543     fatal("Could not enable polling page at " PTR_FORMAT, _polling_page);
3544   }
3545 };
3546 
3547 int os::active_processor_count() {
3548   int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
3549   assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
3550   return online_cpus;
3551 }
3552 
3553 void os::set_native_thread_name(const char *name) {
3554   // Not yet implemented.
3555   return;
3556 }
3557 
3558 bool os::distribute_processes(uint length, uint* distribution) {
3559   // Not yet implemented.
3560   return false;
3561 }
3562 
3563 bool os::bind_to_processor(uint processor_id) {
3564   // Not yet implemented.
3565   return false;
3566 }
3567 
3568 void os::SuspendedThreadTask::internal_do_task() {
3569   if (do_suspend(_thread->osthread())) {
3570     SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
3571     do_task(context);
3572     do_resume(_thread->osthread());
3573   }
3574 }
3575 
3576 ////////////////////////////////////////////////////////////////////////////////
3577 // debug support
3578 
3579 bool os::find(address addr, outputStream* st) {
3580 
3581   st->print(PTR_FORMAT ": ", addr);
3582 
3583   loaded_module_t lm;
3584   if (LoadedLibraries::find_for_text_address(addr, &lm) != NULL ||
3585       LoadedLibraries::find_for_data_address(addr, &lm) != NULL) {
3586     st->print_cr("%s", lm.path);
3587     return true;
3588   }
3589 
3590   return false;
3591 }
3592 
3593 ////////////////////////////////////////////////////////////////////////////////
3594 // misc
3595 
3596 // This does not do anything on Aix. This is basically a hook for being
3597 // able to use structured exception handling (thread-local exception filters)
3598 // on, e.g., Win32.
3599 void
3600 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
3601                          JavaCallArguments* args, Thread* thread) {
3602   f(value, method, args, thread);
3603 }
3604 
3605 void os::print_statistics() {
3606 }
3607 
3608 bool os::message_box(const char* title, const char* message) {
3609   int i;
3610   fdStream err(defaultStream::error_fd());
3611   for (i = 0; i < 78; i++) err.print_raw("=");
3612   err.cr();
3613   err.print_raw_cr(title);
3614   for (i = 0; i < 78; i++) err.print_raw("-");
3615   err.cr();
3616   err.print_raw_cr(message);
3617   for (i = 0; i < 78; i++) err.print_raw("=");
3618   err.cr();
3619 
3620   char buf[16];
3621   // Prevent process from exiting upon "read error" without consuming all CPU
3622   while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
3623 
3624   return buf[0] == 'y' || buf[0] == 'Y';
3625 }
3626 
3627 int os::stat(const char *path, struct stat *sbuf) {
3628   char pathbuf[MAX_PATH];
3629   if (strlen(path) > MAX_PATH - 1) {
3630     errno = ENAMETOOLONG;
3631     return -1;
3632   }
3633   os::native_path(strcpy(pathbuf, path));
3634   return ::stat(pathbuf, sbuf);
3635 }
3636 
3637 // Is a (classpath) directory empty?
3638 bool os::dir_is_empty(const char* path) {
3639   DIR *dir = NULL;
3640   struct dirent *ptr;
3641 
3642   dir = opendir(path);
3643   if (dir == NULL) return true;
3644 
3645   /* Scan the directory */
3646   bool result = true;
3647   char buf[sizeof(struct dirent) + MAX_PATH];
3648   while (result && (ptr = ::readdir(dir)) != NULL) {
3649     if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
3650       result = false;
3651     }
3652   }
3653   closedir(dir);
3654   return result;
3655 }
3656 
3657 // This code originates from JDK's sysOpen and open64_w
3658 // from src/solaris/hpi/src/system_md.c
3659 
3660 int os::open(const char *path, int oflag, int mode) {
3661 
3662   if (strlen(path) > MAX_PATH - 1) {
3663     errno = ENAMETOOLONG;
3664     return -1;
3665   }
3666   int fd;
3667 
3668   fd = ::open64(path, oflag, mode);
3669   if (fd == -1) return -1;
3670 
3671   // If the open succeeded, the file might still be a directory.
3672   {
3673     struct stat64 buf64;
3674     int ret = ::fstat64(fd, &buf64);
3675     int st_mode = buf64.st_mode;
3676 
3677     if (ret != -1) {
3678       if ((st_mode & S_IFMT) == S_IFDIR) {
3679         errno = EISDIR;
3680         ::close(fd);
3681         return -1;
3682       }
3683     } else {
3684       ::close(fd);
3685       return -1;
3686     }
3687   }
3688 
3689   // All file descriptors that are opened in the JVM and not
3690   // specifically destined for a subprocess should have the
3691   // close-on-exec flag set. If we don't set it, then careless 3rd
3692   // party native code might fork and exec without closing all
3693   // appropriate file descriptors (e.g. as we do in closeDescriptors in
3694   // UNIXProcess.c), and this in turn might:
3695   //
3696   // - cause end-of-file to fail to be detected on some file
3697   //   descriptors, resulting in mysterious hangs, or
3698   //
3699   // - might cause an fopen in the subprocess to fail on a system
3700   //   suffering from bug 1085341.
3701   //
3702   // (Yes, the default setting of the close-on-exec flag is a Unix
3703   // design flaw.)
3704   //
3705   // See:
3706   // 1085341: 32-bit stdio routines should support file descriptors >255
3707   // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
3708   // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
3709 #ifdef FD_CLOEXEC
3710   {
3711     int flags = ::fcntl(fd, F_GETFD);
3712     if (flags != -1)
3713       ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
3714   }
3715 #endif
3716 
3717   return fd;
3718 }
3719 
3720 // create binary file, rewriting existing file if required
3721 int os::create_binary_file(const char* path, bool rewrite_existing) {
3722   int oflags = O_WRONLY | O_CREAT;
3723   if (!rewrite_existing) {
3724     oflags |= O_EXCL;
3725   }
3726   return ::open64(path, oflags, S_IREAD | S_IWRITE);
3727 }
3728 
3729 // return current position of file pointer
3730 jlong os::current_file_offset(int fd) {
3731   return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
3732 }
3733 
3734 // move file pointer to the specified offset
3735 jlong os::seek_to_file_offset(int fd, jlong offset) {
3736   return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
3737 }
3738 
3739 // This code originates from JDK's sysAvailable
3740 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
3741 
3742 int os::available(int fd, jlong *bytes) {
3743   jlong cur, end;
3744   int mode;
3745   struct stat64 buf64;
3746 
3747   if (::fstat64(fd, &buf64) >= 0) {
3748     mode = buf64.st_mode;
3749     if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
3750       int n;
3751       if (::ioctl(fd, FIONREAD, &n) >= 0) {
3752         *bytes = n;
3753         return 1;
3754       }
3755     }
3756   }
3757   if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
3758     return 0;
3759   } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
3760     return 0;
3761   } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
3762     return 0;
3763   }
3764   *bytes = end - cur;
3765   return 1;
3766 }
3767 
3768 // Map a block of memory.
3769 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
3770                         char *addr, size_t bytes, bool read_only,
3771                         bool allow_exec) {
3772   int prot;
3773   int flags = MAP_PRIVATE;
3774 
3775   if (read_only) {
3776     prot = PROT_READ;
3777     flags = MAP_SHARED;
3778   } else {
3779     prot = PROT_READ | PROT_WRITE;
3780     flags = MAP_PRIVATE;
3781   }
3782 
3783   if (allow_exec) {
3784     prot |= PROT_EXEC;
3785   }
3786 
3787   if (addr != NULL) {
3788     flags |= MAP_FIXED;
3789   }
3790 
3791   // Allow anonymous mappings if 'fd' is -1.
3792   if (fd == -1) {
3793     flags |= MAP_ANONYMOUS;
3794   }
3795 
3796   char* mapped_address = (char*)::mmap(addr, (size_t)bytes, prot, flags,
3797                                      fd, file_offset);
3798   if (mapped_address == MAP_FAILED) {
3799     return NULL;
3800   }
3801   return mapped_address;
3802 }
3803 
3804 // Remap a block of memory.
3805 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
3806                           char *addr, size_t bytes, bool read_only,
3807                           bool allow_exec) {
3808   // same as map_memory() on this OS
3809   return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
3810                         allow_exec);
3811 }
3812 
3813 // Unmap a block of memory.
3814 bool os::pd_unmap_memory(char* addr, size_t bytes) {
3815   return munmap(addr, bytes) == 0;
3816 }
3817 
3818 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
3819 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
3820 // of a thread.
3821 //
3822 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
3823 // the fast estimate available on the platform.
3824 
3825 jlong os::current_thread_cpu_time() {
3826   // return user + sys since the cost is the same
3827   const jlong n = os::thread_cpu_time(Thread::current(), true /* user + sys */);
3828   assert(n >= 0, "negative CPU time");
3829   return n;
3830 }
3831 
3832 jlong os::thread_cpu_time(Thread* thread) {
3833   // consistent with what current_thread_cpu_time() returns
3834   const jlong n = os::thread_cpu_time(thread, true /* user + sys */);
3835   assert(n >= 0, "negative CPU time");
3836   return n;
3837 }
3838 
3839 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
3840   const jlong n = os::thread_cpu_time(Thread::current(), user_sys_cpu_time);
3841   assert(n >= 0, "negative CPU time");
3842   return n;
3843 }
3844 
3845 static bool thread_cpu_time_unchecked(Thread* thread, jlong* p_sys_time, jlong* p_user_time) {
3846   bool error = false;
3847 
3848   jlong sys_time = 0;
3849   jlong user_time = 0;
3850 
3851   // Reimplemented using getthrds64().
3852   //
3853   // Works like this:
3854   // For the thread in question, get the kernel thread id. Then get the
3855   // kernel thread statistics using that id.
3856   //
3857   // This only works of course when no pthread scheduling is used,
3858   // i.e. there is a 1:1 relationship to kernel threads.
3859   // On AIX, see AIXTHREAD_SCOPE variable.
3860 
3861   pthread_t pthtid = thread->osthread()->pthread_id();
3862 
3863   // retrieve kernel thread id for the pthread:
3864   tid64_t tid = 0;
3865   struct __pthrdsinfo pinfo;
3866   // I just love those otherworldly IBM APIs which force me to hand down
3867   // dummy buffers for stuff I dont care for...
3868   char dummy[1];
3869   int dummy_size = sizeof(dummy);
3870   if (pthread_getthrds_np(&pthtid, PTHRDSINFO_QUERY_TID, &pinfo, sizeof(pinfo),
3871                           dummy, &dummy_size) == 0) {
3872     tid = pinfo.__pi_tid;
3873   } else {
3874     tty->print_cr("pthread_getthrds_np failed.");
3875     error = true;
3876   }
3877 
3878   // retrieve kernel timing info for that kernel thread
3879   if (!error) {
3880     struct thrdentry64 thrdentry;
3881     if (getthrds64(getpid(), &thrdentry, sizeof(thrdentry), &tid, 1) == 1) {
3882       sys_time = thrdentry.ti_ru.ru_stime.tv_sec * 1000000000LL + thrdentry.ti_ru.ru_stime.tv_usec * 1000LL;
3883       user_time = thrdentry.ti_ru.ru_utime.tv_sec * 1000000000LL + thrdentry.ti_ru.ru_utime.tv_usec * 1000LL;
3884     } else {
3885       tty->print_cr("pthread_getthrds_np failed.");
3886       error = true;
3887     }
3888   }
3889 
3890   if (p_sys_time) {
3891     *p_sys_time = sys_time;
3892   }
3893 
3894   if (p_user_time) {
3895     *p_user_time = user_time;
3896   }
3897 
3898   if (error) {
3899     return false;
3900   }
3901 
3902   return true;
3903 }
3904 
3905 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
3906   jlong sys_time;
3907   jlong user_time;
3908 
3909   if (!thread_cpu_time_unchecked(thread, &sys_time, &user_time)) {
3910     return -1;
3911   }
3912 
3913   return user_sys_cpu_time ? sys_time + user_time : user_time;
3914 }
3915 
3916 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
3917   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
3918   info_ptr->may_skip_backward = false;     // elapsed time not wall time
3919   info_ptr->may_skip_forward = false;      // elapsed time not wall time
3920   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
3921 }
3922 
3923 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
3924   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
3925   info_ptr->may_skip_backward = false;     // elapsed time not wall time
3926   info_ptr->may_skip_forward = false;      // elapsed time not wall time
3927   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
3928 }
3929 
3930 bool os::is_thread_cpu_time_supported() {
3931   return true;
3932 }
3933 
3934 // System loadavg support. Returns -1 if load average cannot be obtained.
3935 // For now just return the system wide load average (no processor sets).
3936 int os::loadavg(double values[], int nelem) {
3937 
3938   guarantee(nelem >= 0 && nelem <= 3, "argument error");
3939   guarantee(values, "argument error");
3940 
3941   if (os::Aix::on_pase()) {
3942 
3943     // AS/400 PASE: use libo4 porting library
3944     double v[3] = { 0.0, 0.0, 0.0 };
3945 
3946     if (libo4::get_load_avg(v, v + 1, v + 2)) {
3947       for (int i = 0; i < nelem; i ++) {
3948         values[i] = v[i];
3949       }
3950       return nelem;
3951     } else {
3952       return -1;
3953     }
3954 
3955   } else {
3956 
3957     // AIX: use libperfstat
3958     libperfstat::cpuinfo_t ci;
3959     if (libperfstat::get_cpuinfo(&ci)) {
3960       for (int i = 0; i < nelem; i++) {
3961         values[i] = ci.loadavg[i];
3962       }
3963     } else {
3964       return -1;
3965     }
3966     return nelem;
3967   }
3968 }
3969 
3970 void os::pause() {
3971   char filename[MAX_PATH];
3972   if (PauseAtStartupFile && PauseAtStartupFile[0]) {
3973     jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
3974   } else {
3975     jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
3976   }
3977 
3978   int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
3979   if (fd != -1) {
3980     struct stat buf;
3981     ::close(fd);
3982     while (::stat(filename, &buf) == 0) {
3983       (void)::poll(NULL, 0, 100);
3984     }
3985   } else {
3986     trcVerbose("Could not open pause file '%s', continuing immediately.", filename);
3987   }
3988 }
3989 
3990 bool os::Aix::is_primordial_thread() {
3991   if (pthread_self() == (pthread_t)1) {
3992     return true;
3993   } else {
3994     return false;
3995   }
3996 }
3997 
3998 // OS recognitions (PASE/AIX, OS level) call this before calling any
3999 // one of Aix::on_pase(), Aix::os_version() static
4000 void os::Aix::initialize_os_info() {
4001 
4002   assert(_on_pase == -1 && _os_version == 0, "already called.");
4003 
4004   struct utsname uts;
4005   memset(&uts, 0, sizeof(uts));
4006   strcpy(uts.sysname, "?");
4007   if (::uname(&uts) == -1) {
4008     trcVerbose("uname failed (%d)", errno);
4009     guarantee(0, "Could not determine whether we run on AIX or PASE");
4010   } else {
4011     trcVerbose("uname says: sysname \"%s\" version \"%s\" release \"%s\" "
4012                "node \"%s\" machine \"%s\"\n",
4013                uts.sysname, uts.version, uts.release, uts.nodename, uts.machine);
4014     const int major = atoi(uts.version);
4015     assert(major > 0, "invalid OS version");
4016     const int minor = atoi(uts.release);
4017     assert(minor > 0, "invalid OS release");
4018     _os_version = (major << 24) | (minor << 16);
4019     char ver_str[20] = {0};
4020     char *name_str = "unknown OS";
4021     if (strcmp(uts.sysname, "OS400") == 0) {
4022       // We run on AS/400 PASE. We do not support versions older than V5R4M0.
4023       _on_pase = 1;
4024       if (os_version_short() < 0x0504) {
4025         trcVerbose("OS/400 releases older than V5R4M0 not supported.");
4026         assert(false, "OS/400 release too old.");
4027       }
4028       name_str = "OS/400 (pase)";
4029       jio_snprintf(ver_str, sizeof(ver_str), "%u.%u", major, minor);
4030     } else if (strcmp(uts.sysname, "AIX") == 0) {
4031       // We run on AIX. We do not support versions older than AIX 5.3.
4032       _on_pase = 0;
4033       // Determine detailed AIX version: Version, Release, Modification, Fix Level.
4034       odmWrapper::determine_os_kernel_version(&_os_version);
4035       if (os_version_short() < 0x0503) {
4036         trcVerbose("AIX release older than AIX 5.3 not supported.");
4037         assert(false, "AIX release too old.");
4038       }
4039       name_str = "AIX";
4040       jio_snprintf(ver_str, sizeof(ver_str), "%u.%u.%u.%u",
4041                    major, minor, (_os_version >> 8) & 0xFF, _os_version & 0xFF);
4042     } else {
4043       assert(false, name_str);
4044     }
4045     trcVerbose("We run on %s %s", name_str, ver_str);
4046   }
4047 
4048   guarantee(_on_pase != -1 && _os_version, "Could not determine AIX/OS400 release");
4049 } // end: os::Aix::initialize_os_info()
4050 
4051 // Scan environment for important settings which might effect the VM.
4052 // Trace out settings. Warn about invalid settings and/or correct them.
4053 //
4054 // Must run after os::Aix::initialue_os_info().
4055 void os::Aix::scan_environment() {
4056 
4057   char* p;
4058   int rc;
4059 
4060   // Warn explicity if EXTSHM=ON is used. That switch changes how
4061   // System V shared memory behaves. One effect is that page size of
4062   // shared memory cannot be change dynamically, effectivly preventing
4063   // large pages from working.
4064   // This switch was needed on AIX 32bit, but on AIX 64bit the general
4065   // recommendation is (in OSS notes) to switch it off.
4066   p = ::getenv("EXTSHM");
4067   trcVerbose("EXTSHM=%s.", p ? p : "<unset>");
4068   if (p && strcasecmp(p, "ON") == 0) {
4069     _extshm = 1;
4070     trcVerbose("*** Unsupported mode! Please remove EXTSHM from your environment! ***");
4071     if (!AllowExtshm) {
4072       // We allow under certain conditions the user to continue. However, we want this
4073       // to be a fatal error by default. On certain AIX systems, leaving EXTSHM=ON means
4074       // that the VM is not able to allocate 64k pages for the heap.
4075       // We do not want to run with reduced performance.
4076       vm_exit_during_initialization("EXTSHM is ON. Please remove EXTSHM from your environment.");
4077     }
4078   } else {
4079     _extshm = 0;
4080   }
4081 
4082   // SPEC1170 behaviour: will change the behaviour of a number of POSIX APIs.
4083   // Not tested, not supported.
4084   //
4085   // Note that it might be worth the trouble to test and to require it, if only to
4086   // get useful return codes for mprotect.
4087   //
4088   // Note: Setting XPG_SUS_ENV in the process is too late. Must be set earlier (before
4089   // exec() ? before loading the libjvm ? ....)
4090   p = ::getenv("XPG_SUS_ENV");
4091   trcVerbose("XPG_SUS_ENV=%s.", p ? p : "<unset>");
4092   if (p && strcmp(p, "ON") == 0) {
4093     _xpg_sus_mode = 1;
4094     trcVerbose("Unsupported setting: XPG_SUS_ENV=ON");
4095     // This is not supported. Worst of all, it changes behaviour of mmap MAP_FIXED to
4096     // clobber address ranges. If we ever want to support that, we have to do some
4097     // testing first.
4098     guarantee(false, "XPG_SUS_ENV=ON not supported");
4099   } else {
4100     _xpg_sus_mode = 0;
4101   }
4102 
4103   if (os::Aix::on_pase()) {
4104     p = ::getenv("QIBM_MULTI_THREADED");
4105     trcVerbose("QIBM_MULTI_THREADED=%s.", p ? p : "<unset>");
4106   }
4107 
4108   p = ::getenv("LDR_CNTRL");
4109   trcVerbose("LDR_CNTRL=%s.", p ? p : "<unset>");
4110   if (os::Aix::on_pase() && os::Aix::os_version_short() == 0x0701) {
4111     if (p && ::strstr(p, "TEXTPSIZE")) {
4112       trcVerbose("*** WARNING - LDR_CNTRL contains TEXTPSIZE. "
4113         "you may experience hangs or crashes on OS/400 V7R1.");
4114     }
4115   }
4116 
4117   p = ::getenv("AIXTHREAD_GUARDPAGES");
4118   trcVerbose("AIXTHREAD_GUARDPAGES=%s.", p ? p : "<unset>");
4119 
4120 } // end: os::Aix::scan_environment()
4121 
4122 // PASE: initialize the libo4 library (PASE porting library).
4123 void os::Aix::initialize_libo4() {
4124   guarantee(os::Aix::on_pase(), "OS/400 only.");
4125   if (!libo4::init()) {
4126     trcVerbose("libo4 initialization failed.");
4127     assert(false, "libo4 initialization failed");
4128   } else {
4129     trcVerbose("libo4 initialized.");
4130   }
4131 }
4132 
4133 // AIX: initialize the libperfstat library.
4134 void os::Aix::initialize_libperfstat() {
4135   assert(os::Aix::on_aix(), "AIX only");
4136   if (!libperfstat::init()) {
4137     trcVerbose("libperfstat initialization failed.");
4138     assert(false, "libperfstat initialization failed");
4139   } else {
4140     trcVerbose("libperfstat initialized.");
4141   }
4142 }
4143 
4144 /////////////////////////////////////////////////////////////////////////////
4145 // thread stack
4146 
4147 // Get the current stack base from the OS (actually, the pthread library).
4148 // Note: usually not page aligned.
4149 address os::current_stack_base() {
4150   AixMisc::stackbounds_t bounds;
4151   bool rc = AixMisc::query_stack_bounds_for_current_thread(&bounds);
4152   guarantee(rc, "Unable to retrieve stack bounds.");
4153   return bounds.base;
4154 }
4155 
4156 // Get the current stack size from the OS (actually, the pthread library).
4157 // Returned size is such that (base - size) is always aligned to page size.
4158 size_t os::current_stack_size() {
4159   AixMisc::stackbounds_t bounds;
4160   bool rc = AixMisc::query_stack_bounds_for_current_thread(&bounds);
4161   guarantee(rc, "Unable to retrieve stack bounds.");
4162   // Align the returned stack size such that the stack low address
4163   // is aligned to page size (Note: base is usually not and we do not care).
4164   // We need to do this because caller code will assume stack low address is
4165   // page aligned and will place guard pages without checking.
4166   address low = bounds.base - bounds.size;
4167   address low_aligned = (address)align_up(low, os::vm_page_size());
4168   size_t s = bounds.base - low_aligned;
4169   return s;
4170 }
4171 
4172 extern char** environ;
4173 
4174 // Run the specified command in a separate process. Return its exit value,
4175 // or -1 on failure (e.g. can't fork a new process).
4176 // Unlike system(), this function can be called from signal handler. It
4177 // doesn't block SIGINT et al.
4178 int os::fork_and_exec(char* cmd) {
4179   char * argv[4] = {"sh", "-c", cmd, NULL};
4180 
4181   pid_t pid = fork();
4182 
4183   if (pid < 0) {
4184     // fork failed
4185     return -1;
4186 
4187   } else if (pid == 0) {
4188     // child process
4189 
4190     // Try to be consistent with system(), which uses "/usr/bin/sh" on AIX.
4191     execve("/usr/bin/sh", argv, environ);
4192 
4193     // execve failed
4194     _exit(-1);
4195 
4196   } else {
4197     // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
4198     // care about the actual exit code, for now.
4199 
4200     int status;
4201 
4202     // Wait for the child process to exit. This returns immediately if
4203     // the child has already exited. */
4204     while (waitpid(pid, &status, 0) < 0) {
4205       switch (errno) {
4206         case ECHILD: return 0;
4207         case EINTR: break;
4208         default: return -1;
4209       }
4210     }
4211 
4212     if (WIFEXITED(status)) {
4213       // The child exited normally; get its exit code.
4214       return WEXITSTATUS(status);
4215     } else if (WIFSIGNALED(status)) {
4216       // The child exited because of a signal.
4217       // The best value to return is 0x80 + signal number,
4218       // because that is what all Unix shells do, and because
4219       // it allows callers to distinguish between process exit and
4220       // process death by signal.
4221       return 0x80 + WTERMSIG(status);
4222     } else {
4223       // Unknown exit code; pass it through.
4224       return status;
4225     }
4226   }
4227   return -1;
4228 }
4229 
4230 // is_headless_jre()
4231 //
4232 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
4233 // in order to report if we are running in a headless jre.
4234 //
4235 // Since JDK8 xawt/libmawt.so is moved into the same directory
4236 // as libawt.so, and renamed libawt_xawt.so
4237 bool os::is_headless_jre() {
4238   struct stat statbuf;
4239   char buf[MAXPATHLEN];
4240   char libmawtpath[MAXPATHLEN];
4241   const char *xawtstr = "/xawt/libmawt.so";
4242   const char *new_xawtstr = "/libawt_xawt.so";
4243 
4244   char *p;
4245 
4246   // Get path to libjvm.so
4247   os::jvm_path(buf, sizeof(buf));
4248 
4249   // Get rid of libjvm.so
4250   p = strrchr(buf, '/');
4251   if (p == NULL) return false;
4252   else *p = '\0';
4253 
4254   // Get rid of client or server
4255   p = strrchr(buf, '/');
4256   if (p == NULL) return false;
4257   else *p = '\0';
4258 
4259   // check xawt/libmawt.so
4260   strcpy(libmawtpath, buf);
4261   strcat(libmawtpath, xawtstr);
4262   if (::stat(libmawtpath, &statbuf) == 0) return false;
4263 
4264   // check libawt_xawt.so
4265   strcpy(libmawtpath, buf);
4266   strcat(libmawtpath, new_xawtstr);
4267   if (::stat(libmawtpath, &statbuf) == 0) return false;
4268 
4269   return true;
4270 }
4271 
4272 // Get the default path to the core file
4273 // Returns the length of the string
4274 int os::get_core_path(char* buffer, size_t bufferSize) {
4275   const char* p = get_current_directory(buffer, bufferSize);
4276 
4277   if (p == NULL) {
4278     assert(p != NULL, "failed to get current directory");
4279     return 0;
4280   }
4281 
4282   jio_snprintf(buffer, bufferSize, "%s/core or core.%d",
4283                                                p, current_process_id());
4284 
4285   return strlen(buffer);
4286 }
4287 
4288 #ifndef PRODUCT
4289 void TestReserveMemorySpecial_test() {
4290   // No tests available for this platform
4291 }
4292 #endif
4293 
4294 bool os::start_debugging(char *buf, int buflen) {
4295   int len = (int)strlen(buf);
4296   char *p = &buf[len];
4297 
4298   jio_snprintf(p, buflen -len,
4299                  "\n\n"
4300                  "Do you want to debug the problem?\n\n"
4301                  "To debug, run 'dbx -a %d'; then switch to thread tid " INTX_FORMAT ", k-tid " INTX_FORMAT "\n"
4302                  "Enter 'yes' to launch dbx automatically (PATH must include dbx)\n"
4303                  "Otherwise, press RETURN to abort...",
4304                  os::current_process_id(),
4305                  os::current_thread_id(), thread_self());
4306 
4307   bool yes = os::message_box("Unexpected Error", buf);
4308 
4309   if (yes) {
4310     // yes, user asked VM to launch debugger
4311     jio_snprintf(buf, buflen, "dbx -a %d", os::current_process_id());
4312 
4313     os::fork_and_exec(buf);
4314     yes = false;
4315   }
4316   return yes;
4317 }
4318 
4319 static inline time_t get_mtime(const char* filename) {
4320   struct stat st;
4321   int ret = os::stat(filename, &st);
4322   assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno));
4323   return st.st_mtime;
4324 }
4325 
4326 int os::compare_file_modified_times(const char* file1, const char* file2) {
4327   time_t t1 = get_mtime(file1);
4328   time_t t2 = get_mtime(file2);
4329   return t1 - t2;
4330 }