1 /*
   2  * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "jvm.h"
  27 #include "classfile/classLoader.hpp"
  28 #include "classfile/javaClasses.hpp"
  29 #include "classfile/moduleEntry.hpp"
  30 #include "classfile/systemDictionary.hpp"
  31 #include "classfile/vmSymbols.hpp"
  32 #include "code/codeCache.hpp"
  33 #include "code/icBuffer.hpp"
  34 #include "code/vtableStubs.hpp"
  35 #include "gc/shared/gcVMOperations.hpp"
  36 #include "logging/log.hpp"
  37 #include "interpreter/interpreter.hpp"
  38 #include "logging/log.hpp"
  39 #include "logging/logStream.hpp"
  40 #include "memory/allocation.inline.hpp"
  41 #include "memory/guardedMemory.hpp"
  42 #include "memory/resourceArea.hpp"
  43 #include "memory/universe.hpp"
  44 #include "oops/compressedOops.inline.hpp"
  45 #include "oops/oop.inline.hpp"
  46 #include "prims/jvm_misc.hpp"
  47 #include "runtime/arguments.hpp"
  48 #include "runtime/atomic.hpp"
  49 #include "runtime/frame.inline.hpp"
  50 #include "runtime/handles.inline.hpp"
  51 #include "runtime/interfaceSupport.inline.hpp"
  52 #include "runtime/java.hpp"
  53 #include "runtime/javaCalls.hpp"
  54 #include "runtime/mutexLocker.hpp"
  55 #include "runtime/os.inline.hpp"
  56 #include "runtime/sharedRuntime.hpp"
  57 #include "runtime/stubRoutines.hpp"
  58 #include "runtime/thread.inline.hpp"
  59 #include "runtime/threadSMR.hpp"
  60 #include "runtime/vm_version.hpp"
  61 #include "services/attachListener.hpp"
  62 #include "services/mallocTracker.hpp"
  63 #include "services/memTracker.hpp"
  64 #include "services/nmtCommon.hpp"
  65 #include "services/threadService.hpp"
  66 #include "utilities/align.hpp"
  67 #include "utilities/defaultStream.hpp"
  68 #include "utilities/events.hpp"
  69 
  70 # include <signal.h>
  71 # include <errno.h>
  72 
  73 OSThread*         os::_starting_thread    = NULL;
  74 address           os::_polling_page       = NULL;
  75 volatile unsigned int os::_rand_seed      = 1;
  76 int               os::_processor_count    = 0;
  77 int               os::_initial_active_processor_count = 0;
  78 size_t            os::_page_sizes[os::page_sizes_max];
  79 
  80 #ifndef PRODUCT
  81 julong os::num_mallocs = 0;         // # of calls to malloc/realloc
  82 julong os::alloc_bytes = 0;         // # of bytes allocated
  83 julong os::num_frees = 0;           // # of calls to free
  84 julong os::free_bytes = 0;          // # of bytes freed
  85 #endif
  86 
  87 static size_t cur_malloc_words = 0;  // current size for MallocMaxTestWords
  88 
  89 DEBUG_ONLY(bool os::_mutex_init_done = false;)
  90 
  91 static time_t get_timezone(const struct tm* time_struct) {
  92 #if defined(_ALLBSD_SOURCE)
  93   return time_struct->tm_gmtoff;
  94 #elif defined(_WINDOWS)
  95   long zone;
  96   _get_timezone(&zone);
  97   return static_cast<time_t>(zone);
  98 #else
  99   return timezone;
 100 #endif
 101 }
 102 
 103 int os::snprintf(char* buf, size_t len, const char* fmt, ...) {
 104   va_list args;
 105   va_start(args, fmt);
 106   int result = os::vsnprintf(buf, len, fmt, args);
 107   va_end(args);
 108   return result;
 109 }
 110 
 111 // Fill in buffer with current local time as an ISO-8601 string.
 112 // E.g., yyyy-mm-ddThh:mm:ss-zzzz.
 113 // Returns buffer, or NULL if it failed.
 114 // This would mostly be a call to
 115 //     strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
 116 // except that on Windows the %z behaves badly, so we do it ourselves.
 117 // Also, people wanted milliseconds on there,
 118 // and strftime doesn't do milliseconds.
 119 char* os::iso8601_time(char* buffer, size_t buffer_length, bool utc) {
 120   // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
 121   //                                      1         2
 122   //                             12345678901234567890123456789
 123   // format string: "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d"
 124   static const size_t needed_buffer = 29;
 125 
 126   // Sanity check the arguments
 127   if (buffer == NULL) {
 128     assert(false, "NULL buffer");
 129     return NULL;
 130   }
 131   if (buffer_length < needed_buffer) {
 132     assert(false, "buffer_length too small");
 133     return NULL;
 134   }
 135   // Get the current time
 136   jlong milliseconds_since_19700101 = javaTimeMillis();
 137   const int milliseconds_per_microsecond = 1000;
 138   const time_t seconds_since_19700101 =
 139     milliseconds_since_19700101 / milliseconds_per_microsecond;
 140   const int milliseconds_after_second =
 141     milliseconds_since_19700101 % milliseconds_per_microsecond;
 142   // Convert the time value to a tm and timezone variable
 143   struct tm time_struct;
 144   if (utc) {
 145     if (gmtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
 146       assert(false, "Failed gmtime_pd");
 147       return NULL;
 148     }
 149   } else {
 150     if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
 151       assert(false, "Failed localtime_pd");
 152       return NULL;
 153     }
 154   }
 155   const time_t zone = get_timezone(&time_struct);
 156 
 157   // If daylight savings time is in effect,
 158   // we are 1 hour East of our time zone
 159   const time_t seconds_per_minute = 60;
 160   const time_t minutes_per_hour = 60;
 161   const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
 162   time_t UTC_to_local = zone;
 163   if (time_struct.tm_isdst > 0) {
 164     UTC_to_local = UTC_to_local - seconds_per_hour;
 165   }
 166 
 167   // No offset when dealing with UTC
 168   if (utc) {
 169     UTC_to_local = 0;
 170   }
 171 
 172   // Compute the time zone offset.
 173   //    localtime_pd() sets timezone to the difference (in seconds)
 174   //    between UTC and and local time.
 175   //    ISO 8601 says we need the difference between local time and UTC,
 176   //    we change the sign of the localtime_pd() result.
 177   const time_t local_to_UTC = -(UTC_to_local);
 178   // Then we have to figure out if if we are ahead (+) or behind (-) UTC.
 179   char sign_local_to_UTC = '+';
 180   time_t abs_local_to_UTC = local_to_UTC;
 181   if (local_to_UTC < 0) {
 182     sign_local_to_UTC = '-';
 183     abs_local_to_UTC = -(abs_local_to_UTC);
 184   }
 185   // Convert time zone offset seconds to hours and minutes.
 186   const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
 187   const time_t zone_min =
 188     ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
 189 
 190   // Print an ISO 8601 date and time stamp into the buffer
 191   const int year = 1900 + time_struct.tm_year;
 192   const int month = 1 + time_struct.tm_mon;
 193   const int printed = jio_snprintf(buffer, buffer_length,
 194                                    "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d",
 195                                    year,
 196                                    month,
 197                                    time_struct.tm_mday,
 198                                    time_struct.tm_hour,
 199                                    time_struct.tm_min,
 200                                    time_struct.tm_sec,
 201                                    milliseconds_after_second,
 202                                    sign_local_to_UTC,
 203                                    zone_hours,
 204                                    zone_min);
 205   if (printed == 0) {
 206     assert(false, "Failed jio_printf");
 207     return NULL;
 208   }
 209   return buffer;
 210 }
 211 
 212 OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
 213   debug_only(Thread::check_for_dangling_thread_pointer(thread);)
 214 
 215   if ((p >= MinPriority && p <= MaxPriority) ||
 216       (p == CriticalPriority && thread->is_ConcurrentGC_thread())) {
 217     int priority = java_to_os_priority[p];
 218     return set_native_priority(thread, priority);
 219   } else {
 220     assert(false, "Should not happen");
 221     return OS_ERR;
 222   }
 223 }
 224 
 225 // The mapping from OS priority back to Java priority may be inexact because
 226 // Java priorities can map M:1 with native priorities. If you want the definite
 227 // Java priority then use JavaThread::java_priority()
 228 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
 229   int p;
 230   int os_prio;
 231   OSReturn ret = get_native_priority(thread, &os_prio);
 232   if (ret != OS_OK) return ret;
 233 
 234   if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) {
 235     for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
 236   } else {
 237     // niceness values are in reverse order
 238     for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] < os_prio; p--) ;
 239   }
 240   priority = (ThreadPriority)p;
 241   return OS_OK;
 242 }
 243 
 244 bool os::dll_build_name(char* buffer, size_t size, const char* fname) {
 245   int n = jio_snprintf(buffer, size, "%s%s%s", JNI_LIB_PREFIX, fname, JNI_LIB_SUFFIX);
 246   return (n != -1);
 247 }
 248 
 249 #if !defined(LINUX) && !defined(_WINDOWS)
 250 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
 251   committed_start = start;
 252   committed_size = size;
 253   return true;
 254 }
 255 #endif
 256 
 257 // Helper for dll_locate_lib.
 258 // Pass buffer and printbuffer as we already printed the path to buffer
 259 // when we called get_current_directory. This way we avoid another buffer
 260 // of size MAX_PATH.
 261 static bool conc_path_file_and_check(char *buffer, char *printbuffer, size_t printbuflen,
 262                                      const char* pname, char lastchar, const char* fname) {
 263 
 264   // Concatenate path and file name, but don't print double path separators.
 265   const char *filesep = (WINDOWS_ONLY(lastchar == ':' ||) lastchar == os::file_separator()[0]) ?
 266                         "" : os::file_separator();
 267   int ret = jio_snprintf(printbuffer, printbuflen, "%s%s%s", pname, filesep, fname);
 268   // Check whether file exists.
 269   if (ret != -1) {
 270     struct stat statbuf;
 271     return os::stat(buffer, &statbuf) == 0;
 272   }
 273   return false;
 274 }
 275 
 276 // Frees all memory allocated on the heap for the
 277 // supplied array of arrays of chars (a), where n
 278 // is the number of elements in the array.
 279 static void free_array_of_char_arrays(char** a, size_t n) {
 280       while (n > 0) {
 281           n--;
 282           if (a[n] != NULL) {
 283             FREE_C_HEAP_ARRAY(char, a[n]);
 284           }
 285       }
 286       FREE_C_HEAP_ARRAY(char*, a);
 287 }
 288 
 289 bool os::dll_locate_lib(char *buffer, size_t buflen,
 290                         const char* pname, const char* fname) {
 291   bool retval = false;
 292 
 293   size_t fullfnamelen = strlen(JNI_LIB_PREFIX) + strlen(fname) + strlen(JNI_LIB_SUFFIX);
 294   char* fullfname = NEW_C_HEAP_ARRAY(char, fullfnamelen + 1, mtInternal);
 295   if (dll_build_name(fullfname, fullfnamelen + 1, fname)) {
 296     const size_t pnamelen = pname ? strlen(pname) : 0;
 297 
 298     if (pnamelen == 0) {
 299       // If no path given, use current working directory.
 300       const char* p = get_current_directory(buffer, buflen);
 301       if (p != NULL) {
 302         const size_t plen = strlen(buffer);
 303         const char lastchar = buffer[plen - 1];
 304         retval = conc_path_file_and_check(buffer, &buffer[plen], buflen - plen,
 305                                           "", lastchar, fullfname);
 306       }
 307     } else if (strchr(pname, *os::path_separator()) != NULL) {
 308       // A list of paths. Search for the path that contains the library.
 309       size_t n;
 310       char** pelements = split_path(pname, &n, fullfnamelen);
 311       if (pelements != NULL) {
 312         for (size_t i = 0; i < n; i++) {
 313           char* path = pelements[i];
 314           // Really shouldn't be NULL, but check can't hurt.
 315           size_t plen = (path == NULL) ? 0 : strlen(path);
 316           if (plen == 0) {
 317             continue; // Skip the empty path values.
 318           }
 319           const char lastchar = path[plen - 1];
 320           retval = conc_path_file_and_check(buffer, buffer, buflen, path, lastchar, fullfname);
 321           if (retval) break;
 322         }
 323         // Release the storage allocated by split_path.
 324         free_array_of_char_arrays(pelements, n);
 325       }
 326     } else {
 327       // A definite path.
 328       const char lastchar = pname[pnamelen-1];
 329       retval = conc_path_file_and_check(buffer, buffer, buflen, pname, lastchar, fullfname);
 330     }
 331   }
 332 
 333   FREE_C_HEAP_ARRAY(char*, fullfname);
 334   return retval;
 335 }
 336 
 337 // --------------------- sun.misc.Signal (optional) ---------------------
 338 
 339 
 340 // SIGBREAK is sent by the keyboard to query the VM state
 341 #ifndef SIGBREAK
 342 #define SIGBREAK SIGQUIT
 343 #endif
 344 
 345 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
 346 
 347 
 348 static void signal_thread_entry(JavaThread* thread, TRAPS) {
 349   os::set_priority(thread, NearMaxPriority);
 350   while (true) {
 351     int sig;
 352     {
 353       // FIXME : Currently we have not decided what should be the status
 354       //         for this java thread blocked here. Once we decide about
 355       //         that we should fix this.
 356       sig = os::signal_wait();
 357     }
 358     if (sig == os::sigexitnum_pd()) {
 359        // Terminate the signal thread
 360        return;
 361     }
 362 
 363     switch (sig) {
 364       case SIGBREAK: {
 365 #if INCLUDE_SERVICES
 366         // Check if the signal is a trigger to start the Attach Listener - in that
 367         // case don't print stack traces.
 368         if (!DisableAttachMechanism) {
 369           // Attempt to transit state to AL_INITIALIZING.
 370           AttachListenerState cur_state = AttachListener::transit_state(AL_INITIALIZING, AL_NOT_INITIALIZED);
 371           if (cur_state == AL_INITIALIZING) {
 372             // Attach Listener has been started to initialize. Ignore this signal.
 373             continue;
 374           } else if (cur_state == AL_NOT_INITIALIZED) {
 375             // Start to initialize.
 376             if (AttachListener::is_init_trigger()) {
 377               // Attach Listener has been initialized.
 378               // Accept subsequent request.
 379               continue;
 380             } else {
 381               // Attach Listener could not be started.
 382               // So we need to transit the state to AL_NOT_INITIALIZED.
 383               AttachListener::set_state(AL_NOT_INITIALIZED);
 384             }
 385           } else if (AttachListener::check_socket_file()) {
 386             // Attach Listener has been started, but unix domain socket file
 387             // does not exist. So restart Attach Listener.
 388             continue;
 389           }
 390         }
 391 #endif
 392         // Print stack traces
 393         // Any SIGBREAK operations added here should make sure to flush
 394         // the output stream (e.g. tty->flush()) after output.  See 4803766.
 395         // Each module also prints an extra carriage return after its output.
 396         VM_PrintThreads op;
 397         VMThread::execute(&op);
 398         VM_PrintJNI jni_op;
 399         VMThread::execute(&jni_op);
 400         VM_FindDeadlocks op1(tty);
 401         VMThread::execute(&op1);
 402         Universe::print_heap_at_SIGBREAK();
 403         if (PrintClassHistogram) {
 404           VM_GC_HeapInspection op1(tty, true /* force full GC before heap inspection */);
 405           VMThread::execute(&op1);
 406         }
 407         if (JvmtiExport::should_post_data_dump()) {
 408           JvmtiExport::post_data_dump();
 409         }
 410         break;
 411       }
 412       default: {
 413         // Dispatch the signal to java
 414         HandleMark hm(THREAD);
 415         Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_misc_Signal(), THREAD);
 416         if (klass != NULL) {
 417           JavaValue result(T_VOID);
 418           JavaCallArguments args;
 419           args.push_int(sig);
 420           JavaCalls::call_static(
 421             &result,
 422             klass,
 423             vmSymbols::dispatch_name(),
 424             vmSymbols::int_void_signature(),
 425             &args,
 426             THREAD
 427           );
 428         }
 429         if (HAS_PENDING_EXCEPTION) {
 430           // tty is initialized early so we don't expect it to be null, but
 431           // if it is we can't risk doing an initialization that might
 432           // trigger additional out-of-memory conditions
 433           if (tty != NULL) {
 434             char klass_name[256];
 435             char tmp_sig_name[16];
 436             const char* sig_name = "UNKNOWN";
 437             InstanceKlass::cast(PENDING_EXCEPTION->klass())->
 438               name()->as_klass_external_name(klass_name, 256);
 439             if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
 440               sig_name = tmp_sig_name;
 441             warning("Exception %s occurred dispatching signal %s to handler"
 442                     "- the VM may need to be forcibly terminated",
 443                     klass_name, sig_name );
 444           }
 445           CLEAR_PENDING_EXCEPTION;
 446         }
 447       }
 448     }
 449   }
 450 }
 451 
 452 void os::init_before_ergo() {
 453   initialize_initial_active_processor_count();
 454   // We need to initialize large page support here because ergonomics takes some
 455   // decisions depending on large page support and the calculated large page size.
 456   large_page_init();
 457 
 458   // We need to adapt the configured number of stack protection pages given
 459   // in 4K pages to the actual os page size. We must do this before setting
 460   // up minimal stack sizes etc. in os::init_2().
 461   JavaThread::set_stack_red_zone_size     (align_up(StackRedPages      * 4 * K, vm_page_size()));
 462   JavaThread::set_stack_yellow_zone_size  (align_up(StackYellowPages   * 4 * K, vm_page_size()));
 463   JavaThread::set_stack_reserved_zone_size(align_up(StackReservedPages * 4 * K, vm_page_size()));
 464   JavaThread::set_stack_shadow_zone_size  (align_up(StackShadowPages   * 4 * K, vm_page_size()));
 465 
 466   // VM version initialization identifies some characteristics of the
 467   // platform that are used during ergonomic decisions.
 468   VM_Version::init_before_ergo();
 469 }
 470 
 471 void os::initialize_jdk_signal_support(TRAPS) {
 472   if (!ReduceSignalUsage) {
 473     // Setup JavaThread for processing signals
 474     const char thread_name[] = "Signal Dispatcher";
 475     Handle string = java_lang_String::create_from_str(thread_name, CHECK);
 476 
 477     // Initialize thread_oop to put it into the system threadGroup
 478     Handle thread_group (THREAD, Universe::system_thread_group());
 479     Handle thread_oop = JavaCalls::construct_new_instance(SystemDictionary::Thread_klass(),
 480                            vmSymbols::threadgroup_string_void_signature(),
 481                            thread_group,
 482                            string,
 483                            CHECK);
 484 
 485     Klass* group = SystemDictionary::ThreadGroup_klass();
 486     JavaValue result(T_VOID);
 487     JavaCalls::call_special(&result,
 488                             thread_group,
 489                             group,
 490                             vmSymbols::add_method_name(),
 491                             vmSymbols::thread_void_signature(),
 492                             thread_oop,
 493                             CHECK);
 494 
 495     { MutexLocker mu(Threads_lock);
 496       JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
 497 
 498       // At this point it may be possible that no osthread was created for the
 499       // JavaThread due to lack of memory. We would have to throw an exception
 500       // in that case. However, since this must work and we do not allow
 501       // exceptions anyway, check and abort if this fails.
 502       if (signal_thread == NULL || signal_thread->osthread() == NULL) {
 503         vm_exit_during_initialization("java.lang.OutOfMemoryError",
 504                                       os::native_thread_creation_failed_msg());
 505       }
 506 
 507       java_lang_Thread::set_thread(thread_oop(), signal_thread);
 508       java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
 509       java_lang_Thread::set_daemon(thread_oop());
 510 
 511       signal_thread->set_threadObj(thread_oop());
 512       Threads::add(signal_thread);
 513       Thread::start(signal_thread);
 514     }
 515     // Handle ^BREAK
 516     os::signal(SIGBREAK, os::user_handler());
 517   }
 518 }
 519 
 520 
 521 void os::terminate_signal_thread() {
 522   if (!ReduceSignalUsage)
 523     signal_notify(sigexitnum_pd());
 524 }
 525 
 526 
 527 // --------------------- loading libraries ---------------------
 528 
 529 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
 530 extern struct JavaVM_ main_vm;
 531 
 532 static void* _native_java_library = NULL;
 533 
 534 void* os::native_java_library() {
 535   if (_native_java_library == NULL) {
 536     char buffer[JVM_MAXPATHLEN];
 537     char ebuf[1024];
 538 
 539     // Load java dll
 540     if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 541                        "java")) {
 542       _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
 543     }
 544     if (_native_java_library == NULL) {
 545       vm_exit_during_initialization("Unable to load native library", ebuf);
 546     }
 547 
 548 #if defined(__OpenBSD__)
 549     // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so
 550     // ignore errors
 551     if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 552                        "net")) {
 553       dll_load(buffer, ebuf, sizeof(ebuf));
 554     }
 555 #endif
 556   }
 557   return _native_java_library;
 558 }
 559 
 560 /*
 561  * Support for finding Agent_On(Un)Load/Attach<_lib_name> if it exists.
 562  * If check_lib == true then we are looking for an
 563  * Agent_OnLoad_lib_name or Agent_OnAttach_lib_name function to determine if
 564  * this library is statically linked into the image.
 565  * If check_lib == false then we will look for the appropriate symbol in the
 566  * executable if agent_lib->is_static_lib() == true or in the shared library
 567  * referenced by 'handle'.
 568  */
 569 void* os::find_agent_function(AgentLibrary *agent_lib, bool check_lib,
 570                               const char *syms[], size_t syms_len) {
 571   assert(agent_lib != NULL, "sanity check");
 572   const char *lib_name;
 573   void *handle = agent_lib->os_lib();
 574   void *entryName = NULL;
 575   char *agent_function_name;
 576   size_t i;
 577 
 578   // If checking then use the agent name otherwise test is_static_lib() to
 579   // see how to process this lookup
 580   lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : NULL);
 581   for (i = 0; i < syms_len; i++) {
 582     agent_function_name = build_agent_function_name(syms[i], lib_name, agent_lib->is_absolute_path());
 583     if (agent_function_name == NULL) {
 584       break;
 585     }
 586     entryName = dll_lookup(handle, agent_function_name);
 587     FREE_C_HEAP_ARRAY(char, agent_function_name);
 588     if (entryName != NULL) {
 589       break;
 590     }
 591   }
 592   return entryName;
 593 }
 594 
 595 // See if the passed in agent is statically linked into the VM image.
 596 bool os::find_builtin_agent(AgentLibrary *agent_lib, const char *syms[],
 597                             size_t syms_len) {
 598   void *ret;
 599   void *proc_handle;
 600   void *save_handle;
 601 
 602   assert(agent_lib != NULL, "sanity check");
 603   if (agent_lib->name() == NULL) {
 604     return false;
 605   }
 606   proc_handle = get_default_process_handle();
 607   // Check for Agent_OnLoad/Attach_lib_name function
 608   save_handle = agent_lib->os_lib();
 609   // We want to look in this process' symbol table.
 610   agent_lib->set_os_lib(proc_handle);
 611   ret = find_agent_function(agent_lib, true, syms, syms_len);
 612   if (ret != NULL) {
 613     // Found an entry point like Agent_OnLoad_lib_name so we have a static agent
 614     agent_lib->set_valid();
 615     agent_lib->set_static_lib(true);
 616     return true;
 617   }
 618   agent_lib->set_os_lib(save_handle);
 619   return false;
 620 }
 621 
 622 // --------------------- heap allocation utilities ---------------------
 623 
 624 char *os::strdup(const char *str, MEMFLAGS flags) {
 625   size_t size = strlen(str);
 626   char *dup_str = (char *)malloc(size + 1, flags);
 627   if (dup_str == NULL) return NULL;
 628   strcpy(dup_str, str);
 629   return dup_str;
 630 }
 631 
 632 char* os::strdup_check_oom(const char* str, MEMFLAGS flags) {
 633   char* p = os::strdup(str, flags);
 634   if (p == NULL) {
 635     vm_exit_out_of_memory(strlen(str) + 1, OOM_MALLOC_ERROR, "os::strdup_check_oom");
 636   }
 637   return p;
 638 }
 639 
 640 
 641 #define paranoid                 0  /* only set to 1 if you suspect checking code has bug */
 642 
 643 #ifdef ASSERT
 644 
 645 static void verify_memory(void* ptr) {
 646   GuardedMemory guarded(ptr);
 647   if (!guarded.verify_guards()) {
 648     LogTarget(Warning, malloc, free) lt;
 649     ResourceMark rm;
 650     LogStream ls(lt);
 651     ls.print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees);
 652     ls.print_cr("## memory stomp:");
 653     guarded.print_on(&ls);
 654     fatal("memory stomping error");
 655   }
 656 }
 657 
 658 #endif
 659 
 660 //
 661 // This function supports testing of the malloc out of memory
 662 // condition without really running the system out of memory.
 663 //
 664 static bool has_reached_max_malloc_test_peak(size_t alloc_size) {
 665   if (MallocMaxTestWords > 0) {
 666     size_t words = (alloc_size / BytesPerWord);
 667 
 668     if ((cur_malloc_words + words) > MallocMaxTestWords) {
 669       return true;
 670     }
 671     Atomic::add(&cur_malloc_words, words);
 672   }
 673   return false;
 674 }
 675 
 676 void* os::malloc(size_t size, MEMFLAGS flags) {
 677   return os::malloc(size, flags, CALLER_PC);
 678 }
 679 
 680 void* os::malloc(size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
 681   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 682   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 683 
 684   // Since os::malloc can be called when the libjvm.{dll,so} is
 685   // first loaded and we don't have a thread yet we must accept NULL also here.
 686   assert(!os::ThreadCrashProtection::is_crash_protected(Thread::current_or_null()),
 687          "malloc() not allowed when crash protection is set");
 688 
 689   if (size == 0) {
 690     // return a valid pointer if size is zero
 691     // if NULL is returned the calling functions assume out of memory.
 692     size = 1;
 693   }
 694 
 695   // NMT support
 696   NMT_TrackingLevel level = MemTracker::tracking_level();
 697   size_t            nmt_header_size = MemTracker::malloc_header_size(level);
 698 
 699 #ifndef ASSERT
 700   const size_t alloc_size = size + nmt_header_size;
 701 #else
 702   const size_t alloc_size = GuardedMemory::get_total_size(size + nmt_header_size);
 703   if (size + nmt_header_size > alloc_size) { // Check for rollover.
 704     return NULL;
 705   }
 706 #endif
 707 
 708   // For the test flag -XX:MallocMaxTestWords
 709   if (has_reached_max_malloc_test_peak(size)) {
 710     return NULL;
 711   }
 712 
 713   u_char* ptr;
 714   ptr = (u_char*)::malloc(alloc_size);
 715 
 716 #ifdef ASSERT
 717   if (ptr == NULL) {
 718     return NULL;
 719   }
 720   // Wrap memory with guard
 721   GuardedMemory guarded(ptr, size + nmt_header_size);
 722   ptr = guarded.get_user_ptr();
 723 
 724   if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
 725     log_warning(malloc, free)("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
 726     breakpoint();
 727   }
 728   if (paranoid) {
 729     verify_memory(ptr);
 730   }
 731 #endif
 732 
 733   // we do not track guard memory
 734   return MemTracker::record_malloc((address)ptr, size, memflags, stack, level);
 735 }
 736 
 737 void* os::realloc(void *memblock, size_t size, MEMFLAGS flags) {
 738   return os::realloc(memblock, size, flags, CALLER_PC);
 739 }
 740 
 741 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
 742 
 743   // For the test flag -XX:MallocMaxTestWords
 744   if (has_reached_max_malloc_test_peak(size)) {
 745     return NULL;
 746   }
 747 
 748   if (size == 0) {
 749     // return a valid pointer if size is zero
 750     // if NULL is returned the calling functions assume out of memory.
 751     size = 1;
 752   }
 753 
 754 #ifndef ASSERT
 755   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 756   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 757    // NMT support
 758   NMT_TrackingLevel level = MemTracker::tracking_level();
 759   void* membase = MemTracker::record_free(memblock, level);
 760   size_t  nmt_header_size = MemTracker::malloc_header_size(level);
 761   void* ptr = ::realloc(membase, size + nmt_header_size);
 762   return MemTracker::record_malloc(ptr, size, memflags, stack, level);
 763 #else
 764   if (memblock == NULL) {
 765     return os::malloc(size, memflags, stack);
 766   }
 767   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 768     log_warning(malloc, free)("os::realloc caught " PTR_FORMAT, p2i(memblock));
 769     breakpoint();
 770   }
 771   // NMT support
 772   void* membase = MemTracker::malloc_base(memblock);
 773   verify_memory(membase);
 774   // always move the block
 775   void* ptr = os::malloc(size, memflags, stack);
 776   // Copy to new memory if malloc didn't fail
 777   if (ptr != NULL ) {
 778     GuardedMemory guarded(MemTracker::malloc_base(memblock));
 779     // Guard's user data contains NMT header
 780     size_t memblock_size = guarded.get_user_size() - MemTracker::malloc_header_size(memblock);
 781     memcpy(ptr, memblock, MIN2(size, memblock_size));
 782     if (paranoid) {
 783       verify_memory(MemTracker::malloc_base(ptr));
 784     }
 785     os::free(memblock);
 786   }
 787   return ptr;
 788 #endif
 789 }
 790 
 791 // handles NULL pointers
 792 void  os::free(void *memblock) {
 793   NOT_PRODUCT(inc_stat_counter(&num_frees, 1));
 794 #ifdef ASSERT
 795   if (memblock == NULL) return;
 796   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 797     log_warning(malloc, free)("os::free caught " PTR_FORMAT, p2i(memblock));
 798     breakpoint();
 799   }
 800   void* membase = MemTracker::record_free(memblock, MemTracker::tracking_level());
 801   verify_memory(membase);
 802 
 803   GuardedMemory guarded(membase);
 804   size_t size = guarded.get_user_size();
 805   inc_stat_counter(&free_bytes, size);
 806   membase = guarded.release_for_freeing();
 807   ::free(membase);
 808 #else
 809   void* membase = MemTracker::record_free(memblock, MemTracker::tracking_level());
 810   ::free(membase);
 811 #endif
 812 }
 813 
 814 void os::init_random(unsigned int initval) {
 815   _rand_seed = initval;
 816 }
 817 
 818 
 819 static int random_helper(unsigned int rand_seed) {
 820   /* standard, well-known linear congruential random generator with
 821    * next_rand = (16807*seed) mod (2**31-1)
 822    * see
 823    * (1) "Random Number Generators: Good Ones Are Hard to Find",
 824    *      S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
 825    * (2) "Two Fast Implementations of the 'Minimal Standard' Random
 826    *     Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
 827   */
 828   const unsigned int a = 16807;
 829   const unsigned int m = 2147483647;
 830   const int q = m / a;        assert(q == 127773, "weird math");
 831   const int r = m % a;        assert(r == 2836, "weird math");
 832 
 833   // compute az=2^31p+q
 834   unsigned int lo = a * (rand_seed & 0xFFFF);
 835   unsigned int hi = a * (rand_seed >> 16);
 836   lo += (hi & 0x7FFF) << 16;
 837 
 838   // if q overflowed, ignore the overflow and increment q
 839   if (lo > m) {
 840     lo &= m;
 841     ++lo;
 842   }
 843   lo += hi >> 15;
 844 
 845   // if (p+q) overflowed, ignore the overflow and increment (p+q)
 846   if (lo > m) {
 847     lo &= m;
 848     ++lo;
 849   }
 850   return lo;
 851 }
 852 
 853 int os::random() {
 854   // Make updating the random seed thread safe.
 855   while (true) {
 856     unsigned int seed = _rand_seed;
 857     unsigned int rand = random_helper(seed);
 858     if (Atomic::cmpxchg(rand, &_rand_seed, seed) == seed) {
 859       return static_cast<int>(rand);
 860     }
 861   }
 862 }
 863 
 864 // The INITIALIZED state is distinguished from the SUSPENDED state because the
 865 // conditions in which a thread is first started are different from those in which
 866 // a suspension is resumed.  These differences make it hard for us to apply the
 867 // tougher checks when starting threads that we want to do when resuming them.
 868 // However, when start_thread is called as a result of Thread.start, on a Java
 869 // thread, the operation is synchronized on the Java Thread object.  So there
 870 // cannot be a race to start the thread and hence for the thread to exit while
 871 // we are working on it.  Non-Java threads that start Java threads either have
 872 // to do so in a context in which races are impossible, or should do appropriate
 873 // locking.
 874 
 875 void os::start_thread(Thread* thread) {
 876   // guard suspend/resume
 877   MutexLocker ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
 878   OSThread* osthread = thread->osthread();
 879   osthread->set_state(RUNNABLE);
 880   pd_start_thread(thread);
 881 }
 882 
 883 void os::abort(bool dump_core) {
 884   abort(dump_core && CreateCoredumpOnCrash, NULL, NULL);
 885 }
 886 
 887 //---------------------------------------------------------------------------
 888 // Helper functions for fatal error handler
 889 
 890 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
 891   assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
 892 
 893   start = align_down(start, unitsize);
 894 
 895   int cols = 0;
 896   int cols_per_line = 0;
 897   switch (unitsize) {
 898     case 1: cols_per_line = 16; break;
 899     case 2: cols_per_line = 8;  break;
 900     case 4: cols_per_line = 4;  break;
 901     case 8: cols_per_line = 2;  break;
 902     default: return;
 903   }
 904 
 905   address p = start;
 906   st->print(PTR_FORMAT ":   ", p2i(start));
 907   while (p < end) {
 908     if (is_readable_pointer(p)) {
 909       switch (unitsize) {
 910         case 1: st->print("%02x", *(u1*)p); break;
 911         case 2: st->print("%04x", *(u2*)p); break;
 912         case 4: st->print("%08x", *(u4*)p); break;
 913         case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
 914       }
 915     } else {
 916       st->print("%*.*s", 2*unitsize, 2*unitsize, "????????????????");
 917     }
 918     p += unitsize;
 919     cols++;
 920     if (cols >= cols_per_line && p < end) {
 921        cols = 0;
 922        st->cr();
 923        st->print(PTR_FORMAT ":   ", p2i(p));
 924     } else {
 925        st->print(" ");
 926     }
 927   }
 928   st->cr();
 929 }
 930 
 931 void os::print_instructions(outputStream* st, address pc, int unitsize) {
 932   st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc));
 933   print_hex_dump(st, pc - 256, pc + 256, unitsize);
 934 }
 935 
 936 void os::print_environment_variables(outputStream* st, const char** env_list) {
 937   if (env_list) {
 938     st->print_cr("Environment Variables:");
 939 
 940     for (int i = 0; env_list[i] != NULL; i++) {
 941       char *envvar = ::getenv(env_list[i]);
 942       if (envvar != NULL) {
 943         st->print("%s", env_list[i]);
 944         st->print("=");
 945         st->print_cr("%s", envvar);
 946       }
 947     }
 948   }
 949 }
 950 
 951 void os::print_cpu_info(outputStream* st, char* buf, size_t buflen) {
 952   // cpu
 953   st->print("CPU:");
 954   st->print("total %d", os::processor_count());
 955   // It's not safe to query number of active processors after crash
 956   // st->print("(active %d)", os::active_processor_count()); but we can
 957   // print the initial number of active processors.
 958   // We access the raw value here because the assert in the accessor will
 959   // fail if the crash occurs before initialization of this value.
 960   st->print(" (initial active %d)", _initial_active_processor_count);
 961   st->print(" %s", VM_Version::features_string());
 962   st->cr();
 963   pd_print_cpu_info(st, buf, buflen);
 964 }
 965 
 966 // Print a one line string summarizing the cpu, number of cores, memory, and operating system version
 967 void os::print_summary_info(outputStream* st, char* buf, size_t buflen) {
 968   st->print("Host: ");
 969 #ifndef PRODUCT
 970   if (get_host_name(buf, buflen)) {
 971     st->print("%s, ", buf);
 972   }
 973 #endif // PRODUCT
 974   get_summary_cpu_info(buf, buflen);
 975   st->print("%s, ", buf);
 976   size_t mem = physical_memory()/G;
 977   if (mem == 0) {  // for low memory systems
 978     mem = physical_memory()/M;
 979     st->print("%d cores, " SIZE_FORMAT "M, ", processor_count(), mem);
 980   } else {
 981     st->print("%d cores, " SIZE_FORMAT "G, ", processor_count(), mem);
 982   }
 983   get_summary_os_info(buf, buflen);
 984   st->print_raw(buf);
 985   st->cr();
 986 }
 987 
 988 void os::print_date_and_time(outputStream *st, char* buf, size_t buflen) {
 989   const int secs_per_day  = 86400;
 990   const int secs_per_hour = 3600;
 991   const int secs_per_min  = 60;
 992 
 993   time_t tloc;
 994   (void)time(&tloc);
 995   char* timestring = ctime(&tloc);  // ctime adds newline.
 996   // edit out the newline
 997   char* nl = strchr(timestring, '\n');
 998   if (nl != NULL) {
 999     *nl = '\0';
1000   }
1001 
1002   struct tm tz;
1003   if (localtime_pd(&tloc, &tz) != NULL) {
1004     ::strftime(buf, buflen, "%Z", &tz);
1005     st->print("Time: %s %s", timestring, buf);
1006   } else {
1007     st->print("Time: %s", timestring);
1008   }
1009 
1010   double t = os::elapsedTime();
1011   // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
1012   //       Linux. Must be a bug in glibc ? Workaround is to round "t" to int
1013   //       before printf. We lost some precision, but who cares?
1014   int eltime = (int)t;  // elapsed time in seconds
1015 
1016   // print elapsed time in a human-readable format:
1017   int eldays = eltime / secs_per_day;
1018   int day_secs = eldays * secs_per_day;
1019   int elhours = (eltime - day_secs) / secs_per_hour;
1020   int hour_secs = elhours * secs_per_hour;
1021   int elmins = (eltime - day_secs - hour_secs) / secs_per_min;
1022   int minute_secs = elmins * secs_per_min;
1023   int elsecs = (eltime - day_secs - hour_secs - minute_secs);
1024   st->print_cr(" elapsed time: %d seconds (%dd %dh %dm %ds)", eltime, eldays, elhours, elmins, elsecs);
1025 }
1026 
1027 
1028 // Check if pointer can be read from (4-byte read access).
1029 // Helps to prove validity of a not-NULL pointer.
1030 // Returns true in very early stages of VM life when stub is not yet generated.
1031 #define SAFEFETCH_DEFAULT true
1032 bool os::is_readable_pointer(const void* p) {
1033   if (!CanUseSafeFetch32()) {
1034     return SAFEFETCH_DEFAULT;
1035   }
1036   int* const aligned = (int*) align_down((intptr_t)p, 4);
1037   int cafebabe = 0xcafebabe;  // tester value 1
1038   int deadbeef = 0xdeadbeef;  // tester value 2
1039   return (SafeFetch32(aligned, cafebabe) != cafebabe) || (SafeFetch32(aligned, deadbeef) != deadbeef);
1040 }
1041 
1042 bool os::is_readable_range(const void* from, const void* to) {
1043   if ((uintptr_t)from >= (uintptr_t)to) return false;
1044   for (uintptr_t p = align_down((uintptr_t)from, min_page_size()); p < (uintptr_t)to; p += min_page_size()) {
1045     if (!is_readable_pointer((const void*)p)) {
1046       return false;
1047     }
1048   }
1049   return true;
1050 }
1051 
1052 
1053 // moved from debug.cpp (used to be find()) but still called from there
1054 // The verbose parameter is only set by the debug code in one case
1055 void os::print_location(outputStream* st, intptr_t x, bool verbose) {
1056   address addr = (address)x;
1057   // Handle NULL first, so later checks don't need to protect against it.
1058   if (addr == NULL) {
1059     st->print_cr("0x0 is NULL");
1060     return;
1061   }
1062 
1063   // Check if addr points into a code blob.
1064   CodeBlob* b = CodeCache::find_blob_unsafe(addr);
1065   if (b != NULL) {
1066     b->dump_for_addr(addr, st, verbose);
1067     return;
1068   }
1069 
1070   // Check if addr points into Java heap.
1071   if (Universe::heap()->print_location(st, addr)) {
1072     return;
1073   }
1074 
1075   bool accessible = is_readable_pointer(addr);
1076 
1077   // Check if addr is a JNI handle.
1078   if (align_down((intptr_t)addr, sizeof(intptr_t)) != 0 && accessible) {
1079     if (JNIHandles::is_global_handle((jobject) addr)) {
1080       st->print_cr(INTPTR_FORMAT " is a global jni handle", p2i(addr));
1081       return;
1082     }
1083     if (JNIHandles::is_weak_global_handle((jobject) addr)) {
1084       st->print_cr(INTPTR_FORMAT " is a weak global jni handle", p2i(addr));
1085       return;
1086     }
1087 #ifndef PRODUCT
1088     // we don't keep the block list in product mode
1089     if (JNIHandles::is_local_handle((jobject) addr)) {
1090       st->print_cr(INTPTR_FORMAT " is a local jni handle", p2i(addr));
1091       return;
1092     }
1093 #endif
1094   }
1095 
1096   // Check if addr belongs to a Java thread.
1097   for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
1098     // If the addr is a java thread print information about that.
1099     if (addr == (address)thread) {
1100       if (verbose) {
1101         thread->print_on(st);
1102       } else {
1103         st->print_cr(INTPTR_FORMAT " is a thread", p2i(addr));
1104       }
1105       return;
1106     }
1107     // If the addr is in the stack region for this thread then report that
1108     // and print thread info
1109     if (thread->on_local_stack(addr)) {
1110       st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
1111                    INTPTR_FORMAT, p2i(addr), p2i(thread));
1112       if (verbose) thread->print_on(st);
1113       return;
1114     }
1115   }
1116 
1117   // Check if in metaspace and print types that have vptrs
1118   if (Metaspace::contains(addr)) {
1119     if (Klass::is_valid((Klass*)addr)) {
1120       st->print_cr(INTPTR_FORMAT " is a pointer to class: ", p2i(addr));
1121       ((Klass*)addr)->print_on(st);
1122     } else if (Method::is_valid_method((const Method*)addr)) {
1123       ((Method*)addr)->print_value_on(st);
1124       st->cr();
1125     } else {
1126       // Use addr->print() from the debugger instead (not here)
1127       st->print_cr(INTPTR_FORMAT " is pointing into metadata", p2i(addr));
1128     }
1129     return;
1130   }
1131 
1132   // Compressed klass needs to be decoded first.
1133 #ifdef _LP64
1134   if (UseCompressedClassPointers && ((uintptr_t)addr &~ (uintptr_t)max_juint) == 0) {
1135     narrowKlass narrow_klass = (narrowKlass)(uintptr_t)addr;
1136     Klass* k = CompressedKlassPointers::decode_raw(narrow_klass);
1137 
1138     if (Klass::is_valid(k)) {
1139       st->print_cr(UINT32_FORMAT " is a compressed pointer to class: " INTPTR_FORMAT, narrow_klass, p2i((HeapWord*)k));
1140       k->print_on(st);
1141       return;
1142     }
1143   }
1144 #endif
1145 
1146   // Try an OS specific find
1147   if (os::find(addr, st)) {
1148     return;
1149   }
1150 
1151   if (accessible) {
1152     st->print(INTPTR_FORMAT " points into unknown readable memory:", p2i(addr));
1153     for (address p = addr; p < align_up(addr + 1, sizeof(intptr_t)); ++p) {
1154       st->print(" %02x", *(u1*)p);
1155     }
1156     st->cr();
1157     return;
1158   }
1159 
1160   st->print_cr(INTPTR_FORMAT " is an unknown value", p2i(addr));
1161 }
1162 
1163 // Looks like all platforms can use the same function to check if C
1164 // stack is walkable beyond current frame. The check for fp() is not
1165 // necessary on Sparc, but it's harmless.
1166 bool os::is_first_C_frame(frame* fr) {
1167   // Load up sp, fp, sender sp and sender fp, check for reasonable values.
1168   // Check usp first, because if that's bad the other accessors may fault
1169   // on some architectures.  Ditto ufp second, etc.
1170   uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
1171   // sp on amd can be 32 bit aligned.
1172   uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
1173 
1174   uintptr_t usp    = (uintptr_t)fr->sp();
1175   if ((usp & sp_align_mask) != 0) return true;
1176 
1177   uintptr_t ufp    = (uintptr_t)fr->fp();
1178   if ((ufp & fp_align_mask) != 0) return true;
1179 
1180   uintptr_t old_sp = (uintptr_t)fr->sender_sp();
1181   if ((old_sp & sp_align_mask) != 0) return true;
1182   if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
1183 
1184   uintptr_t old_fp = (uintptr_t)fr->link();
1185   if ((old_fp & fp_align_mask) != 0) return true;
1186   if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
1187 
1188   // stack grows downwards; if old_fp is below current fp or if the stack
1189   // frame is too large, either the stack is corrupted or fp is not saved
1190   // on stack (i.e. on x86, ebp may be used as general register). The stack
1191   // is not walkable beyond current frame.
1192   if (old_fp < ufp) return true;
1193   if (old_fp - ufp > 64 * K) return true;
1194 
1195   return false;
1196 }
1197 
1198 
1199 // Set up the boot classpath.
1200 
1201 char* os::format_boot_path(const char* format_string,
1202                            const char* home,
1203                            int home_len,
1204                            char fileSep,
1205                            char pathSep) {
1206     assert((fileSep == '/' && pathSep == ':') ||
1207            (fileSep == '\\' && pathSep == ';'), "unexpected separator chars");
1208 
1209     // Scan the format string to determine the length of the actual
1210     // boot classpath, and handle platform dependencies as well.
1211     int formatted_path_len = 0;
1212     const char* p;
1213     for (p = format_string; *p != 0; ++p) {
1214         if (*p == '%') formatted_path_len += home_len - 1;
1215         ++formatted_path_len;
1216     }
1217 
1218     char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal);
1219 
1220     // Create boot classpath from format, substituting separator chars and
1221     // java home directory.
1222     char* q = formatted_path;
1223     for (p = format_string; *p != 0; ++p) {
1224         switch (*p) {
1225         case '%':
1226             strcpy(q, home);
1227             q += home_len;
1228             break;
1229         case '/':
1230             *q++ = fileSep;
1231             break;
1232         case ':':
1233             *q++ = pathSep;
1234             break;
1235         default:
1236             *q++ = *p;
1237         }
1238     }
1239     *q = '\0';
1240 
1241     assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
1242     return formatted_path;
1243 }
1244 
1245 // This function is a proxy to fopen, it tries to add a non standard flag ('e' or 'N')
1246 // that ensures automatic closing of the file on exec. If it can not find support in
1247 // the underlying c library, it will make an extra system call (fcntl) to ensure automatic
1248 // closing of the file on exec.
1249 FILE* os::fopen(const char* path, const char* mode) {
1250   char modified_mode[20];
1251   assert(strlen(mode) + 1 < sizeof(modified_mode), "mode chars plus one extra must fit in buffer");
1252   sprintf(modified_mode, "%s" LINUX_ONLY("e") BSD_ONLY("e") WINDOWS_ONLY("N"), mode);
1253   FILE* file = ::fopen(path, modified_mode);
1254 
1255 #if !(defined LINUX || defined BSD || defined _WINDOWS)
1256   // assume fcntl FD_CLOEXEC support as a backup solution when 'e' or 'N'
1257   // is not supported as mode in fopen
1258   if (file != NULL) {
1259     int fd = fileno(file);
1260     if (fd != -1) {
1261       int fd_flags = fcntl(fd, F_GETFD);
1262       if (fd_flags != -1) {
1263         fcntl(fd, F_SETFD, fd_flags | FD_CLOEXEC);
1264       }
1265     }
1266   }
1267 #endif
1268 
1269   return file;
1270 }
1271 
1272 bool os::set_boot_path(char fileSep, char pathSep) {
1273   const char* home = Arguments::get_java_home();
1274   int home_len = (int)strlen(home);
1275 
1276   struct stat st;
1277 
1278   // modular image if "modules" jimage exists
1279   char* jimage = format_boot_path("%/lib/" MODULES_IMAGE_NAME, home, home_len, fileSep, pathSep);
1280   if (jimage == NULL) return false;
1281   bool has_jimage = (os::stat(jimage, &st) == 0);
1282   if (has_jimage) {
1283     Arguments::set_sysclasspath(jimage, true);
1284     FREE_C_HEAP_ARRAY(char, jimage);
1285     return true;
1286   }
1287   FREE_C_HEAP_ARRAY(char, jimage);
1288 
1289   // check if developer build with exploded modules
1290   char* base_classes = format_boot_path("%/modules/" JAVA_BASE_NAME, home, home_len, fileSep, pathSep);
1291   if (base_classes == NULL) return false;
1292   if (os::stat(base_classes, &st) == 0) {
1293     Arguments::set_sysclasspath(base_classes, false);
1294     FREE_C_HEAP_ARRAY(char, base_classes);
1295     return true;
1296   }
1297   FREE_C_HEAP_ARRAY(char, base_classes);
1298 
1299   return false;
1300 }
1301 
1302 // Splits a path, based on its separator, the number of
1303 // elements is returned back in "elements".
1304 // file_name_length is used as a modifier for each path's
1305 // length when compared to JVM_MAXPATHLEN. So if you know
1306 // each returned path will have something appended when
1307 // in use, you can pass the length of that in
1308 // file_name_length, to ensure we detect if any path
1309 // exceeds the maximum path length once prepended onto
1310 // the sub-path/file name.
1311 // It is the callers responsibility to:
1312 //   a> check the value of "elements", which may be 0.
1313 //   b> ignore any empty path elements
1314 //   c> free up the data.
1315 char** os::split_path(const char* path, size_t* elements, size_t file_name_length) {
1316   *elements = (size_t)0;
1317   if (path == NULL || strlen(path) == 0 || file_name_length == (size_t)NULL) {
1318     return NULL;
1319   }
1320   const char psepchar = *os::path_separator();
1321   char* inpath = NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal);
1322   strcpy(inpath, path);
1323   size_t count = 1;
1324   char* p = strchr(inpath, psepchar);
1325   // Get a count of elements to allocate memory
1326   while (p != NULL) {
1327     count++;
1328     p++;
1329     p = strchr(p, psepchar);
1330   }
1331 
1332   char** opath = NEW_C_HEAP_ARRAY(char*, count, mtInternal);
1333 
1334   // do the actual splitting
1335   p = inpath;
1336   for (size_t i = 0 ; i < count ; i++) {
1337     size_t len = strcspn(p, os::path_separator());
1338     if (len + file_name_length > JVM_MAXPATHLEN) {
1339       // release allocated storage before exiting the vm
1340       free_array_of_char_arrays(opath, i++);
1341       vm_exit_during_initialization("The VM tried to use a path that exceeds the maximum path length for "
1342                                     "this system. Review path-containing parameters and properties, such as "
1343                                     "sun.boot.library.path, to identify potential sources for this path.");
1344     }
1345     // allocate the string and add terminator storage
1346     char* s = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
1347     strncpy(s, p, len);
1348     s[len] = '\0';
1349     opath[i] = s;
1350     p += len + 1;
1351   }
1352   FREE_C_HEAP_ARRAY(char, inpath);
1353   *elements = count;
1354   return opath;
1355 }
1356 
1357 // Returns true if the current stack pointer is above the stack shadow
1358 // pages, false otherwise.
1359 bool os::stack_shadow_pages_available(Thread *thread, const methodHandle& method, address sp) {
1360   if (!thread->is_Java_thread()) return false;
1361   // Check if we have StackShadowPages above the yellow zone.  This parameter
1362   // is dependent on the depth of the maximum VM call stack possible from
1363   // the handler for stack overflow.  'instanceof' in the stack overflow
1364   // handler or a println uses at least 8k stack of VM and native code
1365   // respectively.
1366   const int framesize_in_bytes =
1367     Interpreter::size_top_interpreter_activation(method()) * wordSize;
1368 
1369   address limit = ((JavaThread*)thread)->stack_end() +
1370                   (JavaThread::stack_guard_zone_size() + JavaThread::stack_shadow_zone_size());
1371 
1372   return sp > (limit + framesize_in_bytes);
1373 }
1374 
1375 size_t os::page_size_for_region(size_t region_size, size_t min_pages, bool must_be_aligned) {
1376   assert(min_pages > 0, "sanity");
1377   if (UseLargePages) {
1378     const size_t max_page_size = region_size / min_pages;
1379 
1380     for (size_t i = 0; _page_sizes[i] != 0; ++i) {
1381       const size_t page_size = _page_sizes[i];
1382       if (page_size <= max_page_size) {
1383         if (!must_be_aligned || is_aligned(region_size, page_size)) {
1384           return page_size;
1385         }
1386       }
1387     }
1388   }
1389 
1390   return vm_page_size();
1391 }
1392 
1393 size_t os::page_size_for_region_aligned(size_t region_size, size_t min_pages) {
1394   return page_size_for_region(region_size, min_pages, true);
1395 }
1396 
1397 size_t os::page_size_for_region_unaligned(size_t region_size, size_t min_pages) {
1398   return page_size_for_region(region_size, min_pages, false);
1399 }
1400 
1401 static const char* errno_to_string (int e, bool short_text) {
1402   #define ALL_SHARED_ENUMS(X) \
1403     X(E2BIG, "Argument list too long") \
1404     X(EACCES, "Permission denied") \
1405     X(EADDRINUSE, "Address in use") \
1406     X(EADDRNOTAVAIL, "Address not available") \
1407     X(EAFNOSUPPORT, "Address family not supported") \
1408     X(EAGAIN, "Resource unavailable, try again") \
1409     X(EALREADY, "Connection already in progress") \
1410     X(EBADF, "Bad file descriptor") \
1411     X(EBADMSG, "Bad message") \
1412     X(EBUSY, "Device or resource busy") \
1413     X(ECANCELED, "Operation canceled") \
1414     X(ECHILD, "No child processes") \
1415     X(ECONNABORTED, "Connection aborted") \
1416     X(ECONNREFUSED, "Connection refused") \
1417     X(ECONNRESET, "Connection reset") \
1418     X(EDEADLK, "Resource deadlock would occur") \
1419     X(EDESTADDRREQ, "Destination address required") \
1420     X(EDOM, "Mathematics argument out of domain of function") \
1421     X(EEXIST, "File exists") \
1422     X(EFAULT, "Bad address") \
1423     X(EFBIG, "File too large") \
1424     X(EHOSTUNREACH, "Host is unreachable") \
1425     X(EIDRM, "Identifier removed") \
1426     X(EILSEQ, "Illegal byte sequence") \
1427     X(EINPROGRESS, "Operation in progress") \
1428     X(EINTR, "Interrupted function") \
1429     X(EINVAL, "Invalid argument") \
1430     X(EIO, "I/O error") \
1431     X(EISCONN, "Socket is connected") \
1432     X(EISDIR, "Is a directory") \
1433     X(ELOOP, "Too many levels of symbolic links") \
1434     X(EMFILE, "Too many open files") \
1435     X(EMLINK, "Too many links") \
1436     X(EMSGSIZE, "Message too large") \
1437     X(ENAMETOOLONG, "Filename too long") \
1438     X(ENETDOWN, "Network is down") \
1439     X(ENETRESET, "Connection aborted by network") \
1440     X(ENETUNREACH, "Network unreachable") \
1441     X(ENFILE, "Too many files open in system") \
1442     X(ENOBUFS, "No buffer space available") \
1443     X(ENODATA, "No message is available on the STREAM head read queue") \
1444     X(ENODEV, "No such device") \
1445     X(ENOENT, "No such file or directory") \
1446     X(ENOEXEC, "Executable file format error") \
1447     X(ENOLCK, "No locks available") \
1448     X(ENOLINK, "Reserved") \
1449     X(ENOMEM, "Not enough space") \
1450     X(ENOMSG, "No message of the desired type") \
1451     X(ENOPROTOOPT, "Protocol not available") \
1452     X(ENOSPC, "No space left on device") \
1453     X(ENOSR, "No STREAM resources") \
1454     X(ENOSTR, "Not a STREAM") \
1455     X(ENOSYS, "Function not supported") \
1456     X(ENOTCONN, "The socket is not connected") \
1457     X(ENOTDIR, "Not a directory") \
1458     X(ENOTEMPTY, "Directory not empty") \
1459     X(ENOTSOCK, "Not a socket") \
1460     X(ENOTSUP, "Not supported") \
1461     X(ENOTTY, "Inappropriate I/O control operation") \
1462     X(ENXIO, "No such device or address") \
1463     X(EOPNOTSUPP, "Operation not supported on socket") \
1464     X(EOVERFLOW, "Value too large to be stored in data type") \
1465     X(EPERM, "Operation not permitted") \
1466     X(EPIPE, "Broken pipe") \
1467     X(EPROTO, "Protocol error") \
1468     X(EPROTONOSUPPORT, "Protocol not supported") \
1469     X(EPROTOTYPE, "Protocol wrong type for socket") \
1470     X(ERANGE, "Result too large") \
1471     X(EROFS, "Read-only file system") \
1472     X(ESPIPE, "Invalid seek") \
1473     X(ESRCH, "No such process") \
1474     X(ETIME, "Stream ioctl() timeout") \
1475     X(ETIMEDOUT, "Connection timed out") \
1476     X(ETXTBSY, "Text file busy") \
1477     X(EWOULDBLOCK, "Operation would block") \
1478     X(EXDEV, "Cross-device link")
1479 
1480   #define DEFINE_ENTRY(e, text) { e, #e, text },
1481 
1482   static const struct {
1483     int v;
1484     const char* short_text;
1485     const char* long_text;
1486   } table [] = {
1487 
1488     ALL_SHARED_ENUMS(DEFINE_ENTRY)
1489 
1490     // The following enums are not defined on all platforms.
1491     #ifdef ESTALE
1492     DEFINE_ENTRY(ESTALE, "Reserved")
1493     #endif
1494     #ifdef EDQUOT
1495     DEFINE_ENTRY(EDQUOT, "Reserved")
1496     #endif
1497     #ifdef EMULTIHOP
1498     DEFINE_ENTRY(EMULTIHOP, "Reserved")
1499     #endif
1500 
1501     // End marker.
1502     { -1, "Unknown errno", "Unknown error" }
1503 
1504   };
1505 
1506   #undef DEFINE_ENTRY
1507   #undef ALL_FLAGS
1508 
1509   int i = 0;
1510   while (table[i].v != -1 && table[i].v != e) {
1511     i ++;
1512   }
1513 
1514   return short_text ? table[i].short_text : table[i].long_text;
1515 
1516 }
1517 
1518 const char* os::strerror(int e) {
1519   return errno_to_string(e, false);
1520 }
1521 
1522 const char* os::errno_name(int e) {
1523   return errno_to_string(e, true);
1524 }
1525 
1526 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count) {
1527   LogTarget(Info, pagesize) log;
1528   if (log.is_enabled()) {
1529     LogStream out(log);
1530 
1531     out.print("%s: ", str);
1532     for (int i = 0; i < count; ++i) {
1533       out.print(" " SIZE_FORMAT, page_sizes[i]);
1534     }
1535     out.cr();
1536   }
1537 }
1538 
1539 #define trace_page_size_params(size) byte_size_in_exact_unit(size), exact_unit_for_byte_size(size)
1540 
1541 void os::trace_page_sizes(const char* str,
1542                           const size_t region_min_size,
1543                           const size_t region_max_size,
1544                           const size_t page_size,
1545                           const char* base,
1546                           const size_t size) {
1547 
1548   log_info(pagesize)("%s: "
1549                      " min=" SIZE_FORMAT "%s"
1550                      " max=" SIZE_FORMAT "%s"
1551                      " base=" PTR_FORMAT
1552                      " page_size=" SIZE_FORMAT "%s"
1553                      " size=" SIZE_FORMAT "%s",
1554                      str,
1555                      trace_page_size_params(region_min_size),
1556                      trace_page_size_params(region_max_size),
1557                      p2i(base),
1558                      trace_page_size_params(page_size),
1559                      trace_page_size_params(size));
1560 }
1561 
1562 void os::trace_page_sizes_for_requested_size(const char* str,
1563                                              const size_t requested_size,
1564                                              const size_t page_size,
1565                                              const size_t alignment,
1566                                              const char* base,
1567                                              const size_t size) {
1568 
1569   log_info(pagesize)("%s:"
1570                      " req_size=" SIZE_FORMAT "%s"
1571                      " base=" PTR_FORMAT
1572                      " page_size=" SIZE_FORMAT "%s"
1573                      " alignment=" SIZE_FORMAT "%s"
1574                      " size=" SIZE_FORMAT "%s",
1575                      str,
1576                      trace_page_size_params(requested_size),
1577                      p2i(base),
1578                      trace_page_size_params(page_size),
1579                      trace_page_size_params(alignment),
1580                      trace_page_size_params(size));
1581 }
1582 
1583 
1584 // This is the working definition of a server class machine:
1585 // >= 2 physical CPU's and >=2GB of memory, with some fuzz
1586 // because the graphics memory (?) sometimes masks physical memory.
1587 // If you want to change the definition of a server class machine
1588 // on some OS or platform, e.g., >=4GB on Windows platforms,
1589 // then you'll have to parameterize this method based on that state,
1590 // as was done for logical processors here, or replicate and
1591 // specialize this method for each platform.  (Or fix os to have
1592 // some inheritance structure and use subclassing.  Sigh.)
1593 // If you want some platform to always or never behave as a server
1594 // class machine, change the setting of AlwaysActAsServerClassMachine
1595 // and NeverActAsServerClassMachine in globals*.hpp.
1596 bool os::is_server_class_machine() {
1597   // First check for the early returns
1598   if (NeverActAsServerClassMachine) {
1599     return false;
1600   }
1601   if (AlwaysActAsServerClassMachine) {
1602     return true;
1603   }
1604   // Then actually look at the machine
1605   bool         result            = false;
1606   const unsigned int    server_processors = 2;
1607   const julong server_memory     = 2UL * G;
1608   // We seem not to get our full complement of memory.
1609   //     We allow some part (1/8?) of the memory to be "missing",
1610   //     based on the sizes of DIMMs, and maybe graphics cards.
1611   const julong missing_memory   = 256UL * M;
1612 
1613   /* Is this a server class machine? */
1614   if ((os::active_processor_count() >= (int)server_processors) &&
1615       (os::physical_memory() >= (server_memory - missing_memory))) {
1616     const unsigned int logical_processors =
1617       VM_Version::logical_processors_per_package();
1618     if (logical_processors > 1) {
1619       const unsigned int physical_packages =
1620         os::active_processor_count() / logical_processors;
1621       if (physical_packages >= server_processors) {
1622         result = true;
1623       }
1624     } else {
1625       result = true;
1626     }
1627   }
1628   return result;
1629 }
1630 
1631 void os::initialize_initial_active_processor_count() {
1632   assert(_initial_active_processor_count == 0, "Initial active processor count already set.");
1633   _initial_active_processor_count = active_processor_count();
1634   log_debug(os)("Initial active processor count set to %d" , _initial_active_processor_count);
1635 }
1636 
1637 void os::SuspendedThreadTask::run() {
1638   internal_do_task();
1639   _done = true;
1640 }
1641 
1642 bool os::create_stack_guard_pages(char* addr, size_t bytes) {
1643   return os::pd_create_stack_guard_pages(addr, bytes);
1644 }
1645 
1646 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint, int file_desc) {
1647   char* result = NULL;
1648 
1649   if (file_desc != -1) {
1650     // Could have called pd_reserve_memory() followed by replace_existing_mapping_with_file_mapping(),
1651     // but AIX may use SHM in which case its more trouble to detach the segment and remap memory to the file.
1652     result = os::map_memory_to_file(addr, bytes, file_desc);
1653     if (result != NULL) {
1654       MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1655     }
1656   } else {
1657     result = pd_reserve_memory(bytes, addr, alignment_hint);
1658     if (result != NULL) {
1659       MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1660     }
1661   }
1662 
1663   return result;
1664 }
1665 
1666 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint,
1667    MEMFLAGS flags) {
1668   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1669   if (result != NULL) {
1670     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1671     MemTracker::record_virtual_memory_type((address)result, flags);
1672   }
1673 
1674   return result;
1675 }
1676 
1677 char* os::attempt_reserve_memory_at(size_t bytes, char* addr, int file_desc) {
1678   char* result = NULL;
1679   if (file_desc != -1) {
1680     result = pd_attempt_reserve_memory_at(bytes, addr, file_desc);
1681     if (result != NULL) {
1682       MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1683     }
1684   } else {
1685     result = pd_attempt_reserve_memory_at(bytes, addr);
1686     if (result != NULL) {
1687       MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1688     }
1689   }
1690   return result;
1691 }
1692 
1693 void os::split_reserved_memory(char *base, size_t size,
1694                                  size_t split, bool realloc) {
1695   pd_split_reserved_memory(base, size, split, realloc);
1696 }
1697 
1698 bool os::commit_memory(char* addr, size_t bytes, bool executable) {
1699   bool res = pd_commit_memory(addr, bytes, executable);
1700   if (res) {
1701     MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1702   }
1703   return res;
1704 }
1705 
1706 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
1707                               bool executable) {
1708   bool res = os::pd_commit_memory(addr, size, alignment_hint, executable);
1709   if (res) {
1710     MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1711   }
1712   return res;
1713 }
1714 
1715 void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable,
1716                                const char* mesg) {
1717   pd_commit_memory_or_exit(addr, bytes, executable, mesg);
1718   MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1719 }
1720 
1721 void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint,
1722                                bool executable, const char* mesg) {
1723   os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg);
1724   MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1725 }
1726 
1727 bool os::uncommit_memory(char* addr, size_t bytes) {
1728   bool res;
1729   if (MemTracker::tracking_level() > NMT_minimal) {
1730     Tracker tkr(Tracker::uncommit);
1731     res = pd_uncommit_memory(addr, bytes);
1732     if (res) {
1733       tkr.record((address)addr, bytes);
1734     }
1735   } else {
1736     res = pd_uncommit_memory(addr, bytes);
1737   }
1738   return res;
1739 }
1740 
1741 bool os::release_memory(char* addr, size_t bytes) {
1742   bool res;
1743   if (MemTracker::tracking_level() > NMT_minimal) {
1744     Tracker tkr(Tracker::release);
1745     res = pd_release_memory(addr, bytes);
1746     if (res) {
1747       tkr.record((address)addr, bytes);
1748     }
1749   } else {
1750     res = pd_release_memory(addr, bytes);
1751   }
1752   return res;
1753 }
1754 
1755 void os::pretouch_memory(void* start, void* end, size_t page_size) {
1756   for (volatile char *p = (char*)start; p < (char*)end; p += page_size) {
1757     *p = 0;
1758   }
1759 }
1760 
1761 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
1762                            char *addr, size_t bytes, bool read_only,
1763                            bool allow_exec) {
1764   char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec);
1765   if (result != NULL) {
1766     MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1767   }
1768   return result;
1769 }
1770 
1771 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
1772                              char *addr, size_t bytes, bool read_only,
1773                              bool allow_exec) {
1774   return pd_remap_memory(fd, file_name, file_offset, addr, bytes,
1775                     read_only, allow_exec);
1776 }
1777 
1778 bool os::unmap_memory(char *addr, size_t bytes) {
1779   bool result;
1780   if (MemTracker::tracking_level() > NMT_minimal) {
1781     Tracker tkr(Tracker::release);
1782     result = pd_unmap_memory(addr, bytes);
1783     if (result) {
1784       tkr.record((address)addr, bytes);
1785     }
1786   } else {
1787     result = pd_unmap_memory(addr, bytes);
1788   }
1789   return result;
1790 }
1791 
1792 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
1793   pd_free_memory(addr, bytes, alignment_hint);
1794 }
1795 
1796 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
1797   pd_realign_memory(addr, bytes, alignment_hint);
1798 }
1799 
1800 #ifndef _WINDOWS
1801 /* try to switch state from state "from" to state "to"
1802  * returns the state set after the method is complete
1803  */
1804 os::SuspendResume::State os::SuspendResume::switch_state(os::SuspendResume::State from,
1805                                                          os::SuspendResume::State to)
1806 {
1807   os::SuspendResume::State result = Atomic::cmpxchg(to, &_state, from);
1808   if (result == from) {
1809     // success
1810     return to;
1811   }
1812   return result;
1813 }
1814 #endif
1815 
1816 // Convenience wrapper around naked_short_sleep to allow for longer sleep
1817 // times. Only for use by non-JavaThreads.
1818 void os::naked_sleep(jlong millis) {
1819   assert(!Thread::current()->is_Java_thread(), "not for use by JavaThreads");
1820   const jlong limit = 999;
1821   while (millis > limit) {
1822     naked_short_sleep(limit);
1823     millis -= limit;
1824   }
1825   naked_short_sleep(millis);
1826 }
--- EOF ---