1 /*
   2  * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoader.hpp"
  27 #include "classfile/javaClasses.hpp"
  28 #include "classfile/systemDictionary.hpp"
  29 #include "classfile/vmSymbols.hpp"
  30 #include "code/codeCache.hpp"
  31 #include "code/icBuffer.hpp"
  32 #include "code/vtableStubs.hpp"
  33 #include "gc/shared/vmGCOperations.hpp"
  34 #include "interpreter/interpreter.hpp"
  35 #include "logging/log.hpp"
  36 #include "memory/allocation.inline.hpp"
  37 #ifdef ASSERT
  38 #include "memory/guardedMemory.hpp"
  39 #endif
  40 #include "oops/oop.inline.hpp"
  41 #include "prims/jvm.h"
  42 #include "prims/jvm_misc.hpp"
  43 #include "prims/privilegedStack.hpp"
  44 #include "runtime/arguments.hpp"
  45 #include "runtime/atomic.inline.hpp"
  46 #include "runtime/frame.inline.hpp"
  47 #include "runtime/interfaceSupport.hpp"
  48 #include "runtime/java.hpp"
  49 #include "runtime/javaCalls.hpp"
  50 #include "runtime/mutexLocker.hpp"
  51 #include "runtime/os.inline.hpp"
  52 #include "runtime/stubRoutines.hpp"
  53 #include "runtime/thread.inline.hpp"
  54 #include "runtime/vm_version.hpp"
  55 #include "services/attachListener.hpp"
  56 #include "services/mallocTracker.hpp"
  57 #include "services/memTracker.hpp"
  58 #include "services/nmtCommon.hpp"
  59 #include "services/threadService.hpp"
  60 #include "utilities/defaultStream.hpp"
  61 #include "utilities/events.hpp"
  62 
  63 # include <signal.h>
  64 
  65 OSThread*         os::_starting_thread    = NULL;
  66 address           os::_polling_page       = NULL;
  67 volatile int32_t* os::_mem_serialize_page = NULL;
  68 uintptr_t         os::_serialize_page_mask = 0;
  69 long              os::_rand_seed          = 1;
  70 int               os::_processor_count    = 0;
  71 size_t            os::_page_sizes[os::page_sizes_max];
  72 
  73 #ifndef PRODUCT
  74 julong os::num_mallocs = 0;         // # of calls to malloc/realloc
  75 julong os::alloc_bytes = 0;         // # of bytes allocated
  76 julong os::num_frees = 0;           // # of calls to free
  77 julong os::free_bytes = 0;          // # of bytes freed
  78 #endif
  79 
  80 static juint cur_malloc_words = 0;  // current size for MallocMaxTestWords
  81 
  82 void os_init_globals() {
  83   // Called from init_globals().
  84   // See Threads::create_vm() in thread.cpp, and init.cpp.
  85   os::init_globals();
  86 }
  87 
  88 // Fill in buffer with current local time as an ISO-8601 string.
  89 // E.g., yyyy-mm-ddThh:mm:ss-zzzz.
  90 // Returns buffer, or NULL if it failed.
  91 // This would mostly be a call to
  92 //     strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
  93 // except that on Windows the %z behaves badly, so we do it ourselves.
  94 // Also, people wanted milliseconds on there,
  95 // and strftime doesn't do milliseconds.
  96 char* os::iso8601_time(char* buffer, size_t buffer_length) {
  97   // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
  98   //                                      1         2
  99   //                             12345678901234567890123456789
 100   // format string: "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d"
 101   static const size_t needed_buffer = 29;
 102 
 103   // Sanity check the arguments
 104   if (buffer == NULL) {
 105     assert(false, "NULL buffer");
 106     return NULL;
 107   }
 108   if (buffer_length < needed_buffer) {
 109     assert(false, "buffer_length too small");
 110     return NULL;
 111   }
 112   // Get the current time
 113   jlong milliseconds_since_19700101 = javaTimeMillis();
 114   const int milliseconds_per_microsecond = 1000;
 115   const time_t seconds_since_19700101 =
 116     milliseconds_since_19700101 / milliseconds_per_microsecond;
 117   const int milliseconds_after_second =
 118     milliseconds_since_19700101 % milliseconds_per_microsecond;
 119   // Convert the time value to a tm and timezone variable
 120   struct tm time_struct;
 121   if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
 122     assert(false, "Failed localtime_pd");
 123     return NULL;
 124   }
 125 #if defined(_ALLBSD_SOURCE)
 126   const time_t zone = (time_t) time_struct.tm_gmtoff;
 127 #else
 128   const time_t zone = timezone;
 129 #endif
 130 
 131   // If daylight savings time is in effect,
 132   // we are 1 hour East of our time zone
 133   const time_t seconds_per_minute = 60;
 134   const time_t minutes_per_hour = 60;
 135   const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
 136   time_t UTC_to_local = zone;
 137   if (time_struct.tm_isdst > 0) {
 138     UTC_to_local = UTC_to_local - seconds_per_hour;
 139   }
 140   // Compute the time zone offset.
 141   //    localtime_pd() sets timezone to the difference (in seconds)
 142   //    between UTC and and local time.
 143   //    ISO 8601 says we need the difference between local time and UTC,
 144   //    we change the sign of the localtime_pd() result.
 145   const time_t local_to_UTC = -(UTC_to_local);
 146   // Then we have to figure out if if we are ahead (+) or behind (-) UTC.
 147   char sign_local_to_UTC = '+';
 148   time_t abs_local_to_UTC = local_to_UTC;
 149   if (local_to_UTC < 0) {
 150     sign_local_to_UTC = '-';
 151     abs_local_to_UTC = -(abs_local_to_UTC);
 152   }
 153   // Convert time zone offset seconds to hours and minutes.
 154   const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
 155   const time_t zone_min =
 156     ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
 157 
 158   // Print an ISO 8601 date and time stamp into the buffer
 159   const int year = 1900 + time_struct.tm_year;
 160   const int month = 1 + time_struct.tm_mon;
 161   const int printed = jio_snprintf(buffer, buffer_length,
 162                                    "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d",
 163                                    year,
 164                                    month,
 165                                    time_struct.tm_mday,
 166                                    time_struct.tm_hour,
 167                                    time_struct.tm_min,
 168                                    time_struct.tm_sec,
 169                                    milliseconds_after_second,
 170                                    sign_local_to_UTC,
 171                                    zone_hours,
 172                                    zone_min);
 173   if (printed == 0) {
 174     assert(false, "Failed jio_printf");
 175     return NULL;
 176   }
 177   return buffer;
 178 }
 179 
 180 OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
 181 #ifdef ASSERT
 182   if (!(!thread->is_Java_thread() ||
 183          Thread::current() == thread  ||
 184          Threads_lock->owned_by_self()
 185          || thread->is_Compiler_thread()
 186         )) {
 187     assert(false, "possibility of dangling Thread pointer");
 188   }
 189 #endif
 190 
 191   if (p >= MinPriority && p <= MaxPriority) {
 192     int priority = java_to_os_priority[p];
 193     return set_native_priority(thread, priority);
 194   } else {
 195     assert(false, "Should not happen");
 196     return OS_ERR;
 197   }
 198 }
 199 
 200 // The mapping from OS priority back to Java priority may be inexact because
 201 // Java priorities can map M:1 with native priorities. If you want the definite
 202 // Java priority then use JavaThread::java_priority()
 203 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
 204   int p;
 205   int os_prio;
 206   OSReturn ret = get_native_priority(thread, &os_prio);
 207   if (ret != OS_OK) return ret;
 208 
 209   if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) {
 210     for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
 211   } else {
 212     // niceness values are in reverse order
 213     for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] < os_prio; p--) ;
 214   }
 215   priority = (ThreadPriority)p;
 216   return OS_OK;
 217 }
 218 
 219 
 220 // --------------------- sun.misc.Signal (optional) ---------------------
 221 
 222 
 223 // SIGBREAK is sent by the keyboard to query the VM state
 224 #ifndef SIGBREAK
 225 #define SIGBREAK SIGQUIT
 226 #endif
 227 
 228 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
 229 
 230 
 231 static void signal_thread_entry(JavaThread* thread, TRAPS) {
 232   os::set_priority(thread, NearMaxPriority);
 233   while (true) {
 234     int sig;
 235     {
 236       // FIXME : Currently we have not decided what should be the status
 237       //         for this java thread blocked here. Once we decide about
 238       //         that we should fix this.
 239       sig = os::signal_wait();
 240     }
 241     if (sig == os::sigexitnum_pd()) {
 242        // Terminate the signal thread
 243        return;
 244     }
 245 
 246     switch (sig) {
 247       case SIGBREAK: {
 248         // Check if the signal is a trigger to start the Attach Listener - in that
 249         // case don't print stack traces.
 250         if (!DisableAttachMechanism && AttachListener::is_init_trigger()) {
 251           continue;
 252         }
 253         // Print stack traces
 254         // Any SIGBREAK operations added here should make sure to flush
 255         // the output stream (e.g. tty->flush()) after output.  See 4803766.
 256         // Each module also prints an extra carriage return after its output.
 257         VM_PrintThreads op;
 258         VMThread::execute(&op);
 259         VM_PrintJNI jni_op;
 260         VMThread::execute(&jni_op);
 261         VM_FindDeadlocks op1(tty);
 262         VMThread::execute(&op1);
 263         Universe::print_heap_at_SIGBREAK();
 264         if (PrintClassHistogram) {
 265           VM_GC_HeapInspection op1(gclog_or_tty, true /* force full GC before heap inspection */);
 266           VMThread::execute(&op1);
 267         }
 268         if (JvmtiExport::should_post_data_dump()) {
 269           JvmtiExport::post_data_dump();
 270         }
 271         break;
 272       }
 273       default: {
 274         // Dispatch the signal to java
 275         HandleMark hm(THREAD);
 276         Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_Signal(), THREAD);
 277         KlassHandle klass (THREAD, k);
 278         if (klass.not_null()) {
 279           JavaValue result(T_VOID);
 280           JavaCallArguments args;
 281           args.push_int(sig);
 282           JavaCalls::call_static(
 283             &result,
 284             klass,
 285             vmSymbols::dispatch_name(),
 286             vmSymbols::int_void_signature(),
 287             &args,
 288             THREAD
 289           );
 290         }
 291         if (HAS_PENDING_EXCEPTION) {
 292           // tty is initialized early so we don't expect it to be null, but
 293           // if it is we can't risk doing an initialization that might
 294           // trigger additional out-of-memory conditions
 295           if (tty != NULL) {
 296             char klass_name[256];
 297             char tmp_sig_name[16];
 298             const char* sig_name = "UNKNOWN";
 299             InstanceKlass::cast(PENDING_EXCEPTION->klass())->
 300               name()->as_klass_external_name(klass_name, 256);
 301             if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
 302               sig_name = tmp_sig_name;
 303             warning("Exception %s occurred dispatching signal %s to handler"
 304                     "- the VM may need to be forcibly terminated",
 305                     klass_name, sig_name );
 306           }
 307           CLEAR_PENDING_EXCEPTION;
 308         }
 309       }
 310     }
 311   }
 312 }
 313 
 314 void os::init_before_ergo() {
 315   // We need to initialize large page support here because ergonomics takes some
 316   // decisions depending on large page support and the calculated large page size.
 317   large_page_init();
 318 }
 319 
 320 void os::signal_init() {
 321   if (!ReduceSignalUsage) {
 322     // Setup JavaThread for processing signals
 323     EXCEPTION_MARK;
 324     Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
 325     instanceKlassHandle klass (THREAD, k);
 326     instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
 327 
 328     const char thread_name[] = "Signal Dispatcher";
 329     Handle string = java_lang_String::create_from_str(thread_name, CHECK);
 330 
 331     // Initialize thread_oop to put it into the system threadGroup
 332     Handle thread_group (THREAD, Universe::system_thread_group());
 333     JavaValue result(T_VOID);
 334     JavaCalls::call_special(&result, thread_oop,
 335                            klass,
 336                            vmSymbols::object_initializer_name(),
 337                            vmSymbols::threadgroup_string_void_signature(),
 338                            thread_group,
 339                            string,
 340                            CHECK);
 341 
 342     KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
 343     JavaCalls::call_special(&result,
 344                             thread_group,
 345                             group,
 346                             vmSymbols::add_method_name(),
 347                             vmSymbols::thread_void_signature(),
 348                             thread_oop,         // ARG 1
 349                             CHECK);
 350 
 351     os::signal_init_pd();
 352 
 353     { MutexLocker mu(Threads_lock);
 354       JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
 355 
 356       // At this point it may be possible that no osthread was created for the
 357       // JavaThread due to lack of memory. We would have to throw an exception
 358       // in that case. However, since this must work and we do not allow
 359       // exceptions anyway, check and abort if this fails.
 360       if (signal_thread == NULL || signal_thread->osthread() == NULL) {
 361         vm_exit_during_initialization("java.lang.OutOfMemoryError",
 362                                       os::native_thread_creation_failed_msg());
 363       }
 364 
 365       java_lang_Thread::set_thread(thread_oop(), signal_thread);
 366       java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
 367       java_lang_Thread::set_daemon(thread_oop());
 368 
 369       signal_thread->set_threadObj(thread_oop());
 370       Threads::add(signal_thread);
 371       Thread::start(signal_thread);
 372     }
 373     // Handle ^BREAK
 374     os::signal(SIGBREAK, os::user_handler());
 375   }
 376 }
 377 
 378 
 379 void os::terminate_signal_thread() {
 380   if (!ReduceSignalUsage)
 381     signal_notify(sigexitnum_pd());
 382 }
 383 
 384 
 385 // --------------------- loading libraries ---------------------
 386 
 387 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
 388 extern struct JavaVM_ main_vm;
 389 
 390 static void* _native_java_library = NULL;
 391 
 392 void* os::native_java_library() {
 393   if (_native_java_library == NULL) {
 394     char buffer[JVM_MAXPATHLEN];
 395     char ebuf[1024];
 396 
 397     // Try to load verify dll first. In 1.3 java dll depends on it and is not
 398     // always able to find it when the loading executable is outside the JDK.
 399     // In order to keep working with 1.2 we ignore any loading errors.
 400     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 401                        "verify")) {
 402       dll_load(buffer, ebuf, sizeof(ebuf));
 403     }
 404 
 405     // Load java dll
 406     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 407                        "java")) {
 408       _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
 409     }
 410     if (_native_java_library == NULL) {
 411       vm_exit_during_initialization("Unable to load native library", ebuf);
 412     }
 413 
 414 #if defined(__OpenBSD__)
 415     // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so
 416     // ignore errors
 417     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 418                        "net")) {
 419       dll_load(buffer, ebuf, sizeof(ebuf));
 420     }
 421 #endif
 422   }
 423   static jboolean onLoaded = JNI_FALSE;
 424   if (onLoaded) {
 425     // We may have to wait to fire OnLoad until TLS is initialized.
 426     if (ThreadLocalStorage::is_initialized()) {
 427       // The JNI_OnLoad handling is normally done by method load in
 428       // java.lang.ClassLoader$NativeLibrary, but the VM loads the base library
 429       // explicitly so we have to check for JNI_OnLoad as well
 430       const char *onLoadSymbols[] = JNI_ONLOAD_SYMBOLS;
 431       JNI_OnLoad_t JNI_OnLoad = CAST_TO_FN_PTR(
 432           JNI_OnLoad_t, dll_lookup(_native_java_library, onLoadSymbols[0]));
 433       if (JNI_OnLoad != NULL) {
 434         JavaThread* thread = JavaThread::current();
 435         ThreadToNativeFromVM ttn(thread);
 436         HandleMark hm(thread);
 437         jint ver = (*JNI_OnLoad)(&main_vm, NULL);
 438         onLoaded = JNI_TRUE;
 439         if (!Threads::is_supported_jni_version_including_1_1(ver)) {
 440           vm_exit_during_initialization("Unsupported JNI version");
 441         }
 442       }
 443     }
 444   }
 445   return _native_java_library;
 446 }
 447 
 448 /*
 449  * Support for finding Agent_On(Un)Load/Attach<_lib_name> if it exists.
 450  * If check_lib == true then we are looking for an
 451  * Agent_OnLoad_lib_name or Agent_OnAttach_lib_name function to determine if
 452  * this library is statically linked into the image.
 453  * If check_lib == false then we will look for the appropriate symbol in the
 454  * executable if agent_lib->is_static_lib() == true or in the shared library
 455  * referenced by 'handle'.
 456  */
 457 void* os::find_agent_function(AgentLibrary *agent_lib, bool check_lib,
 458                               const char *syms[], size_t syms_len) {
 459   assert(agent_lib != NULL, "sanity check");
 460   const char *lib_name;
 461   void *handle = agent_lib->os_lib();
 462   void *entryName = NULL;
 463   char *agent_function_name;
 464   size_t i;
 465 
 466   // If checking then use the agent name otherwise test is_static_lib() to
 467   // see how to process this lookup
 468   lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : NULL);
 469   for (i = 0; i < syms_len; i++) {
 470     agent_function_name = build_agent_function_name(syms[i], lib_name, agent_lib->is_absolute_path());
 471     if (agent_function_name == NULL) {
 472       break;
 473     }
 474     entryName = dll_lookup(handle, agent_function_name);
 475     FREE_C_HEAP_ARRAY(char, agent_function_name);
 476     if (entryName != NULL) {
 477       break;
 478     }
 479   }
 480   return entryName;
 481 }
 482 
 483 // See if the passed in agent is statically linked into the VM image.
 484 bool os::find_builtin_agent(AgentLibrary *agent_lib, const char *syms[],
 485                             size_t syms_len) {
 486   void *ret;
 487   void *proc_handle;
 488   void *save_handle;
 489 
 490   assert(agent_lib != NULL, "sanity check");
 491   if (agent_lib->name() == NULL) {
 492     return false;
 493   }
 494   proc_handle = get_default_process_handle();
 495   // Check for Agent_OnLoad/Attach_lib_name function
 496   save_handle = agent_lib->os_lib();
 497   // We want to look in this process' symbol table.
 498   agent_lib->set_os_lib(proc_handle);
 499   ret = find_agent_function(agent_lib, true, syms, syms_len);
 500   if (ret != NULL) {
 501     // Found an entry point like Agent_OnLoad_lib_name so we have a static agent
 502     agent_lib->set_valid();
 503     agent_lib->set_static_lib(true);
 504     return true;
 505   }
 506   agent_lib->set_os_lib(save_handle);
 507   return false;
 508 }
 509 
 510 // --------------------- heap allocation utilities ---------------------
 511 
 512 char *os::strdup(const char *str, MEMFLAGS flags) {
 513   size_t size = strlen(str);
 514   char *dup_str = (char *)malloc(size + 1, flags);
 515   if (dup_str == NULL) return NULL;
 516   strcpy(dup_str, str);
 517   return dup_str;
 518 }
 519 
 520 char* os::strdup_check_oom(const char* str, MEMFLAGS flags) {
 521   char* p = os::strdup(str, flags);
 522   if (p == NULL) {
 523     vm_exit_out_of_memory(strlen(str) + 1, OOM_MALLOC_ERROR, "os::strdup_check_oom");
 524   }
 525   return p;
 526 }
 527 
 528 
 529 #define paranoid                 0  /* only set to 1 if you suspect checking code has bug */
 530 
 531 #ifdef ASSERT
 532 
 533 static void verify_memory(void* ptr) {
 534   GuardedMemory guarded(ptr);
 535   if (!guarded.verify_guards()) {
 536     tty->print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees);
 537     tty->print_cr("## memory stomp:");
 538     guarded.print_on(tty);
 539     fatal("memory stomping error");
 540   }
 541 }
 542 
 543 #endif
 544 
 545 //
 546 // This function supports testing of the malloc out of memory
 547 // condition without really running the system out of memory.
 548 //
 549 static bool has_reached_max_malloc_test_peak(size_t alloc_size) {
 550   if (MallocMaxTestWords > 0) {
 551     jint words = (jint)(alloc_size / BytesPerWord);
 552 
 553     if ((cur_malloc_words + words) > MallocMaxTestWords) {
 554       return true;
 555     }
 556     Atomic::add(words, (volatile jint *)&cur_malloc_words);
 557   }
 558   return false;
 559 }
 560 
 561 void* os::malloc(size_t size, MEMFLAGS flags) {
 562   return os::malloc(size, flags, CALLER_PC);
 563 }
 564 
 565 void* os::malloc(size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
 566   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 567   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 568 
 569 #ifdef ASSERT
 570   // checking for the WatcherThread and crash_protection first
 571   // since os::malloc can be called when the libjvm.{dll,so} is
 572   // first loaded and we don't have a thread yet.
 573   // try to find the thread after we see that the watcher thread
 574   // exists and has crash protection.
 575   WatcherThread *wt = WatcherThread::watcher_thread();
 576   if (wt != NULL && wt->has_crash_protection()) {
 577     Thread* thread = ThreadLocalStorage::get_thread_slow();
 578     if (thread == wt) {
 579       assert(!wt->has_crash_protection(),
 580           "Can't malloc with crash protection from WatcherThread");
 581     }
 582   }
 583 #endif
 584 
 585   if (size == 0) {
 586     // return a valid pointer if size is zero
 587     // if NULL is returned the calling functions assume out of memory.
 588     size = 1;
 589   }
 590 
 591   // NMT support
 592   NMT_TrackingLevel level = MemTracker::tracking_level();
 593   size_t            nmt_header_size = MemTracker::malloc_header_size(level);
 594 
 595 #ifndef ASSERT
 596   const size_t alloc_size = size + nmt_header_size;
 597 #else
 598   const size_t alloc_size = GuardedMemory::get_total_size(size + nmt_header_size);
 599   if (size + nmt_header_size > alloc_size) { // Check for rollover.
 600     return NULL;
 601   }
 602 #endif
 603 
 604   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 605 
 606   // For the test flag -XX:MallocMaxTestWords
 607   if (has_reached_max_malloc_test_peak(size)) {
 608     return NULL;
 609   }
 610 
 611   u_char* ptr;
 612   ptr = (u_char*)::malloc(alloc_size);
 613 
 614 #ifdef ASSERT
 615   if (ptr == NULL) {
 616     return NULL;
 617   }
 618   // Wrap memory with guard
 619   GuardedMemory guarded(ptr, size + nmt_header_size);
 620   ptr = guarded.get_user_ptr();
 621 #endif
 622   if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
 623     tty->print_cr("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
 624     breakpoint();
 625   }
 626   debug_only(if (paranoid) verify_memory(ptr));
 627   if (PrintMalloc && tty != NULL) {
 628     tty->print_cr("os::malloc " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
 629   }
 630 
 631   // we do not track guard memory
 632   return MemTracker::record_malloc((address)ptr, size, memflags, stack, level);
 633 }
 634 
 635 void* os::realloc(void *memblock, size_t size, MEMFLAGS flags) {
 636   return os::realloc(memblock, size, flags, CALLER_PC);
 637 }
 638 
 639 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
 640 
 641   // For the test flag -XX:MallocMaxTestWords
 642   if (has_reached_max_malloc_test_peak(size)) {
 643     return NULL;
 644   }
 645 
 646 #ifndef ASSERT
 647   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 648   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 649    // NMT support
 650   void* membase = MemTracker::record_free(memblock);
 651   NMT_TrackingLevel level = MemTracker::tracking_level();
 652   size_t  nmt_header_size = MemTracker::malloc_header_size(level);
 653   void* ptr = ::realloc(membase, size + nmt_header_size);
 654   return MemTracker::record_malloc(ptr, size, memflags, stack, level);
 655 #else
 656   if (memblock == NULL) {
 657     return os::malloc(size, memflags, stack);
 658   }
 659   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 660     tty->print_cr("os::realloc caught " PTR_FORMAT, p2i(memblock));
 661     breakpoint();
 662   }
 663   // NMT support
 664   void* membase = MemTracker::malloc_base(memblock);
 665   verify_memory(membase);
 666   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 667   if (size == 0) {
 668     return NULL;
 669   }
 670   // always move the block
 671   void* ptr = os::malloc(size, memflags, stack);
 672   if (PrintMalloc && tty != NULL) {
 673     tty->print_cr("os::realloc " SIZE_FORMAT " bytes, " PTR_FORMAT " --> " PTR_FORMAT, size, p2i(memblock), p2i(ptr));
 674   }
 675   // Copy to new memory if malloc didn't fail
 676   if ( ptr != NULL ) {
 677     GuardedMemory guarded(MemTracker::malloc_base(memblock));
 678     // Guard's user data contains NMT header
 679     size_t memblock_size = guarded.get_user_size() - MemTracker::malloc_header_size(memblock);
 680     memcpy(ptr, memblock, MIN2(size, memblock_size));
 681     if (paranoid) verify_memory(MemTracker::malloc_base(ptr));
 682     if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
 683       tty->print_cr("os::realloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
 684       breakpoint();
 685     }
 686     os::free(memblock);
 687   }
 688   return ptr;
 689 #endif
 690 }
 691 
 692 
 693 void  os::free(void *memblock) {
 694   NOT_PRODUCT(inc_stat_counter(&num_frees, 1));
 695 #ifdef ASSERT
 696   if (memblock == NULL) return;
 697   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 698     if (tty != NULL) tty->print_cr("os::free caught " PTR_FORMAT, p2i(memblock));
 699     breakpoint();
 700   }
 701   void* membase = MemTracker::record_free(memblock);
 702   verify_memory(membase);
 703   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 704 
 705   GuardedMemory guarded(membase);
 706   size_t size = guarded.get_user_size();
 707   inc_stat_counter(&free_bytes, size);
 708   membase = guarded.release_for_freeing();
 709   if (PrintMalloc && tty != NULL) {
 710       fprintf(stderr, "os::free " SIZE_FORMAT " bytes --> " PTR_FORMAT "\n", size, (uintptr_t)membase);
 711   }
 712   ::free(membase);
 713 #else
 714   void* membase = MemTracker::record_free(memblock);
 715   ::free(membase);
 716 #endif
 717 }
 718 
 719 void os::init_random(long initval) {
 720   _rand_seed = initval;
 721 }
 722 
 723 
 724 long os::random() {
 725   /* standard, well-known linear congruential random generator with
 726    * next_rand = (16807*seed) mod (2**31-1)
 727    * see
 728    * (1) "Random Number Generators: Good Ones Are Hard to Find",
 729    *      S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
 730    * (2) "Two Fast Implementations of the 'Minimal Standard' Random
 731    *     Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
 732   */
 733   const long a = 16807;
 734   const unsigned long m = 2147483647;
 735   const long q = m / a;        assert(q == 127773, "weird math");
 736   const long r = m % a;        assert(r == 2836, "weird math");
 737 
 738   // compute az=2^31p+q
 739   unsigned long lo = a * (long)(_rand_seed & 0xFFFF);
 740   unsigned long hi = a * (long)((unsigned long)_rand_seed >> 16);
 741   lo += (hi & 0x7FFF) << 16;
 742 
 743   // if q overflowed, ignore the overflow and increment q
 744   if (lo > m) {
 745     lo &= m;
 746     ++lo;
 747   }
 748   lo += hi >> 15;
 749 
 750   // if (p+q) overflowed, ignore the overflow and increment (p+q)
 751   if (lo > m) {
 752     lo &= m;
 753     ++lo;
 754   }
 755   return (_rand_seed = lo);
 756 }
 757 
 758 // The INITIALIZED state is distinguished from the SUSPENDED state because the
 759 // conditions in which a thread is first started are different from those in which
 760 // a suspension is resumed.  These differences make it hard for us to apply the
 761 // tougher checks when starting threads that we want to do when resuming them.
 762 // However, when start_thread is called as a result of Thread.start, on a Java
 763 // thread, the operation is synchronized on the Java Thread object.  So there
 764 // cannot be a race to start the thread and hence for the thread to exit while
 765 // we are working on it.  Non-Java threads that start Java threads either have
 766 // to do so in a context in which races are impossible, or should do appropriate
 767 // locking.
 768 
 769 void os::start_thread(Thread* thread) {
 770   // guard suspend/resume
 771   MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
 772   OSThread* osthread = thread->osthread();
 773   osthread->set_state(RUNNABLE);
 774   pd_start_thread(thread);
 775 }
 776 
 777 void os::abort(bool dump_core) {
 778   abort(dump_core && CreateCoredumpOnCrash, NULL, NULL);
 779 }
 780 
 781 //---------------------------------------------------------------------------
 782 // Helper functions for fatal error handler
 783 
 784 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
 785   assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
 786 
 787   int cols = 0;
 788   int cols_per_line = 0;
 789   switch (unitsize) {
 790     case 1: cols_per_line = 16; break;
 791     case 2: cols_per_line = 8;  break;
 792     case 4: cols_per_line = 4;  break;
 793     case 8: cols_per_line = 2;  break;
 794     default: return;
 795   }
 796 
 797   address p = start;
 798   st->print(PTR_FORMAT ":   ", p2i(start));
 799   while (p < end) {
 800     switch (unitsize) {
 801       case 1: st->print("%02x", *(u1*)p); break;
 802       case 2: st->print("%04x", *(u2*)p); break;
 803       case 4: st->print("%08x", *(u4*)p); break;
 804       case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
 805     }
 806     p += unitsize;
 807     cols++;
 808     if (cols >= cols_per_line && p < end) {
 809        cols = 0;
 810        st->cr();
 811        st->print(PTR_FORMAT ":   ", p2i(p));
 812     } else {
 813        st->print(" ");
 814     }
 815   }
 816   st->cr();
 817 }
 818 
 819 void os::print_environment_variables(outputStream* st, const char** env_list) {
 820   if (env_list) {
 821     st->print_cr("Environment Variables:");
 822 
 823     for (int i = 0; env_list[i] != NULL; i++) {
 824       char *envvar = ::getenv(env_list[i]);
 825       if (envvar != NULL) {
 826         st->print("%s", env_list[i]);
 827         st->print("=");
 828         st->print_cr("%s", envvar);
 829       }
 830     }
 831   }
 832 }
 833 
 834 void os::print_cpu_info(outputStream* st, char* buf, size_t buflen) {
 835   // cpu
 836   st->print("CPU:");
 837   st->print("total %d", os::processor_count());
 838   // It's not safe to query number of active processors after crash
 839   // st->print("(active %d)", os::active_processor_count());
 840   st->print(" %s", VM_Version::cpu_features());
 841   st->cr();
 842   pd_print_cpu_info(st, buf, buflen);
 843 }
 844 
 845 // Print a one line string summarizing the cpu, number of cores, memory, and operating system version
 846 void os::print_summary_info(outputStream* st, char* buf, size_t buflen) {
 847   st->print("Host: ");
 848 #ifndef PRODUCT
 849   if (get_host_name(buf, buflen)) {
 850     st->print("%s, ", buf);
 851   }
 852 #endif // PRODUCT
 853   get_summary_cpu_info(buf, buflen);
 854   st->print("%s, ", buf);
 855   size_t mem = physical_memory()/G;
 856   if (mem == 0) {  // for low memory systems
 857     mem = physical_memory()/M;
 858     st->print("%d cores, " SIZE_FORMAT "M, ", processor_count(), mem);
 859   } else {
 860     st->print("%d cores, " SIZE_FORMAT "G, ", processor_count(), mem);
 861   }
 862   get_summary_os_info(buf, buflen);
 863   st->print_raw(buf);
 864   st->cr();
 865 }
 866 
 867 void os::print_date_and_time(outputStream *st, char* buf, size_t buflen) {
 868   const int secs_per_day  = 86400;
 869   const int secs_per_hour = 3600;
 870   const int secs_per_min  = 60;
 871 
 872   time_t tloc;
 873   (void)time(&tloc);
 874   char* timestring = ctime(&tloc);  // ctime adds newline.
 875   // edit out the newline
 876   char* nl = strchr(timestring, '\n');
 877   if (nl != NULL) {
 878     *nl = '\0';
 879   }
 880 
 881   struct tm tz;
 882   if (localtime_pd(&tloc, &tz) != NULL) {
 883     ::strftime(buf, buflen, "%Z", &tz);
 884     st->print("Time: %s %s", timestring, buf);
 885   } else {
 886     st->print("Time: %s", timestring);
 887   }
 888 
 889   double t = os::elapsedTime();
 890   // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
 891   //       Linux. Must be a bug in glibc ? Workaround is to round "t" to int
 892   //       before printf. We lost some precision, but who cares?
 893   int eltime = (int)t;  // elapsed time in seconds
 894 
 895   // print elapsed time in a human-readable format:
 896   int eldays = eltime / secs_per_day;
 897   int day_secs = eldays * secs_per_day;
 898   int elhours = (eltime - day_secs) / secs_per_hour;
 899   int hour_secs = elhours * secs_per_hour;
 900   int elmins = (eltime - day_secs - hour_secs) / secs_per_min;
 901   int minute_secs = elmins * secs_per_min;
 902   int elsecs = (eltime - day_secs - hour_secs - minute_secs);
 903   st->print_cr(" elapsed time: %d seconds (%dd %dh %dm %ds)", eltime, eldays, elhours, elmins, elsecs);
 904 }
 905 
 906 // moved from debug.cpp (used to be find()) but still called from there
 907 // The verbose parameter is only set by the debug code in one case
 908 void os::print_location(outputStream* st, intptr_t x, bool verbose) {
 909   address addr = (address)x;
 910   CodeBlob* b = CodeCache::find_blob_unsafe(addr);
 911   if (b != NULL) {
 912     if (b->is_buffer_blob()) {
 913       // the interpreter is generated into a buffer blob
 914       InterpreterCodelet* i = Interpreter::codelet_containing(addr);
 915       if (i != NULL) {
 916         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an Interpreter codelet", p2i(addr), (int)(addr - i->code_begin()));
 917         i->print_on(st);
 918         return;
 919       }
 920       if (Interpreter::contains(addr)) {
 921         st->print_cr(INTPTR_FORMAT " is pointing into interpreter code"
 922                      " (not bytecode specific)", p2i(addr));
 923         return;
 924       }
 925       //
 926       if (AdapterHandlerLibrary::contains(b)) {
 927         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an AdapterHandler", p2i(addr), (int)(addr - b->code_begin()));
 928         AdapterHandlerLibrary::print_handler_on(st, b);
 929       }
 930       // the stubroutines are generated into a buffer blob
 931       StubCodeDesc* d = StubCodeDesc::desc_for(addr);
 932       if (d != NULL) {
 933         st->print_cr(INTPTR_FORMAT " is at begin+%d in a stub", p2i(addr), (int)(addr - d->begin()));
 934         d->print_on(st);
 935         st->cr();
 936         return;
 937       }
 938       if (StubRoutines::contains(addr)) {
 939         st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) stub routine", p2i(addr));
 940         return;
 941       }
 942       // the InlineCacheBuffer is using stubs generated into a buffer blob
 943       if (InlineCacheBuffer::contains(addr)) {
 944         st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", p2i(addr));
 945         return;
 946       }
 947       VtableStub* v = VtableStubs::stub_containing(addr);
 948       if (v != NULL) {
 949         st->print_cr(INTPTR_FORMAT " is at entry_point+%d in a vtable stub", p2i(addr), (int)(addr - v->entry_point()));
 950         v->print_on(st);
 951         st->cr();
 952         return;
 953       }
 954     }
 955     nmethod* nm = b->as_nmethod_or_null();
 956     if (nm != NULL) {
 957       ResourceMark rm;
 958       st->print(INTPTR_FORMAT " is at entry_point+%d in (nmethod*)" INTPTR_FORMAT,
 959                 p2i(addr), (int)(addr - nm->entry_point()), p2i(nm));
 960       if (verbose) {
 961         st->print(" for ");
 962         nm->method()->print_value_on(st);
 963       }
 964       st->cr();
 965       nm->print_nmethod(verbose);
 966       return;
 967     }
 968     st->print_cr(INTPTR_FORMAT " is at code_begin+%d in ", p2i(addr), (int)(addr - b->code_begin()));
 969     b->print_on(st);
 970     return;
 971   }
 972 
 973   if (Universe::heap()->is_in(addr)) {
 974     HeapWord* p = Universe::heap()->block_start(addr);
 975     bool print = false;
 976     // If we couldn't find it it just may mean that heap wasn't parsable
 977     // See if we were just given an oop directly
 978     if (p != NULL && Universe::heap()->block_is_obj(p)) {
 979       print = true;
 980     } else if (p == NULL && ((oopDesc*)addr)->is_oop()) {
 981       p = (HeapWord*) addr;
 982       print = true;
 983     }
 984     if (print) {
 985       if (p == (HeapWord*) addr) {
 986         st->print_cr(INTPTR_FORMAT " is an oop", p2i(addr));
 987       } else {
 988         st->print_cr(INTPTR_FORMAT " is pointing into object: " INTPTR_FORMAT, p2i(addr), p2i(p));
 989       }
 990       oop(p)->print_on(st);
 991       return;
 992     }
 993   } else {
 994     if (Universe::heap()->is_in_reserved(addr)) {
 995       st->print_cr(INTPTR_FORMAT " is an unallocated location "
 996                    "in the heap", p2i(addr));
 997       return;
 998     }
 999   }
1000   if (JNIHandles::is_global_handle((jobject) addr)) {
1001     st->print_cr(INTPTR_FORMAT " is a global jni handle", p2i(addr));
1002     return;
1003   }
1004   if (JNIHandles::is_weak_global_handle((jobject) addr)) {
1005     st->print_cr(INTPTR_FORMAT " is a weak global jni handle", p2i(addr));
1006     return;
1007   }
1008 #ifndef PRODUCT
1009   // we don't keep the block list in product mode
1010   if (JNIHandleBlock::any_contains((jobject) addr)) {
1011     st->print_cr(INTPTR_FORMAT " is a local jni handle", p2i(addr));
1012     return;
1013   }
1014 #endif
1015 
1016   for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
1017     // Check for privilege stack
1018     if (thread->privileged_stack_top() != NULL &&
1019         thread->privileged_stack_top()->contains(addr)) {
1020       st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack "
1021                    "for thread: " INTPTR_FORMAT, p2i(addr), p2i(thread));
1022       if (verbose) thread->print_on(st);
1023       return;
1024     }
1025     // If the addr is a java thread print information about that.
1026     if (addr == (address)thread) {
1027       if (verbose) {
1028         thread->print_on(st);
1029       } else {
1030         st->print_cr(INTPTR_FORMAT " is a thread", p2i(addr));
1031       }
1032       return;
1033     }
1034     // If the addr is in the stack region for this thread then report that
1035     // and print thread info
1036     if (thread->stack_base() >= addr &&
1037         addr > (thread->stack_base() - thread->stack_size())) {
1038       st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
1039                    INTPTR_FORMAT, p2i(addr), p2i(thread));
1040       if (verbose) thread->print_on(st);
1041       return;
1042     }
1043 
1044   }
1045 
1046   // Check if in metaspace and print types that have vptrs (only method now)
1047   if (Metaspace::contains(addr)) {
1048     if (Method::has_method_vptr((const void*)addr)) {
1049       ((Method*)addr)->print_value_on(st);
1050       st->cr();
1051     } else {
1052       // Use addr->print() from the debugger instead (not here)
1053       st->print_cr(INTPTR_FORMAT " is pointing into metadata", p2i(addr));
1054     }
1055     return;
1056   }
1057 
1058   // Try an OS specific find
1059   if (os::find(addr, st)) {
1060     return;
1061   }
1062 
1063   st->print_cr(INTPTR_FORMAT " is an unknown value", p2i(addr));
1064 }
1065 
1066 // Looks like all platforms except IA64 can use the same function to check
1067 // if C stack is walkable beyond current frame. The check for fp() is not
1068 // necessary on Sparc, but it's harmless.
1069 bool os::is_first_C_frame(frame* fr) {
1070 #if (defined(IA64) && !defined(AIX)) && !defined(_WIN32)
1071   // On IA64 we have to check if the callers bsp is still valid
1072   // (i.e. within the register stack bounds).
1073   // Notice: this only works for threads created by the VM and only if
1074   // we walk the current stack!!! If we want to be able to walk
1075   // arbitrary other threads, we'll have to somehow store the thread
1076   // object in the frame.
1077   Thread *thread = Thread::current();
1078   if ((address)fr->fp() <=
1079       thread->register_stack_base() HPUX_ONLY(+ 0x0) LINUX_ONLY(+ 0x50)) {
1080     // This check is a little hacky, because on Linux the first C
1081     // frame's ('start_thread') register stack frame starts at
1082     // "register_stack_base + 0x48" while on HPUX, the first C frame's
1083     // ('__pthread_bound_body') register stack frame seems to really
1084     // start at "register_stack_base".
1085     return true;
1086   } else {
1087     return false;
1088   }
1089 #elif defined(IA64) && defined(_WIN32)
1090   return true;
1091 #else
1092   // Load up sp, fp, sender sp and sender fp, check for reasonable values.
1093   // Check usp first, because if that's bad the other accessors may fault
1094   // on some architectures.  Ditto ufp second, etc.
1095   uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
1096   // sp on amd can be 32 bit aligned.
1097   uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
1098 
1099   uintptr_t usp    = (uintptr_t)fr->sp();
1100   if ((usp & sp_align_mask) != 0) return true;
1101 
1102   uintptr_t ufp    = (uintptr_t)fr->fp();
1103   if ((ufp & fp_align_mask) != 0) return true;
1104 
1105   uintptr_t old_sp = (uintptr_t)fr->sender_sp();
1106   if ((old_sp & sp_align_mask) != 0) return true;
1107   if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
1108 
1109   uintptr_t old_fp = (uintptr_t)fr->link();
1110   if ((old_fp & fp_align_mask) != 0) return true;
1111   if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
1112 
1113   // stack grows downwards; if old_fp is below current fp or if the stack
1114   // frame is too large, either the stack is corrupted or fp is not saved
1115   // on stack (i.e. on x86, ebp may be used as general register). The stack
1116   // is not walkable beyond current frame.
1117   if (old_fp < ufp) return true;
1118   if (old_fp - ufp > 64 * K) return true;
1119 
1120   return false;
1121 #endif
1122 }
1123 
1124 #ifdef ASSERT
1125 extern "C" void test_random() {
1126   const double m = 2147483647;
1127   double mean = 0.0, variance = 0.0, t;
1128   long reps = 10000;
1129   unsigned long seed = 1;
1130 
1131   tty->print_cr("seed %ld for %ld repeats...", seed, reps);
1132   os::init_random(seed);
1133   long num;
1134   for (int k = 0; k < reps; k++) {
1135     num = os::random();
1136     double u = (double)num / m;
1137     assert(u >= 0.0 && u <= 1.0, "bad random number!");
1138 
1139     // calculate mean and variance of the random sequence
1140     mean += u;
1141     variance += (u*u);
1142   }
1143   mean /= reps;
1144   variance /= (reps - 1);
1145 
1146   assert(num == 1043618065, "bad seed");
1147   tty->print_cr("mean of the 1st 10000 numbers: %f", mean);
1148   tty->print_cr("variance of the 1st 10000 numbers: %f", variance);
1149   const double eps = 0.0001;
1150   t = fabsd(mean - 0.5018);
1151   assert(t < eps, "bad mean");
1152   t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355;
1153   assert(t < eps, "bad variance");
1154 }
1155 #endif
1156 
1157 
1158 // Set up the boot classpath.
1159 
1160 char* os::format_boot_path(const char* format_string,
1161                            const char* home,
1162                            int home_len,
1163                            char fileSep,
1164                            char pathSep) {
1165     assert((fileSep == '/' && pathSep == ':') ||
1166            (fileSep == '\\' && pathSep == ';'), "unexpected separator chars");
1167 
1168     // Scan the format string to determine the length of the actual
1169     // boot classpath, and handle platform dependencies as well.
1170     int formatted_path_len = 0;
1171     const char* p;
1172     for (p = format_string; *p != 0; ++p) {
1173         if (*p == '%') formatted_path_len += home_len - 1;
1174         ++formatted_path_len;
1175     }
1176 
1177     char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal);
1178     if (formatted_path == NULL) {
1179         return NULL;
1180     }
1181 
1182     // Create boot classpath from format, substituting separator chars and
1183     // java home directory.
1184     char* q = formatted_path;
1185     for (p = format_string; *p != 0; ++p) {
1186         switch (*p) {
1187         case '%':
1188             strcpy(q, home);
1189             q += home_len;
1190             break;
1191         case '/':
1192             *q++ = fileSep;
1193             break;
1194         case ':':
1195             *q++ = pathSep;
1196             break;
1197         default:
1198             *q++ = *p;
1199         }
1200     }
1201     *q = '\0';
1202 
1203     assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
1204     return formatted_path;
1205 }
1206 
1207 // returns a PATH of all entries in the given directory that do not start with a '.'
1208 static char* expand_entries_to_path(char* directory, char fileSep, char pathSep) {
1209   DIR* dir = os::opendir(directory);
1210   if (dir == NULL) return NULL;
1211 
1212   char* path = NULL;
1213   size_t path_len = 0;  // path length including \0 terminator
1214 
1215   size_t directory_len = strlen(directory);
1216   struct dirent *entry;
1217   char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(directory), mtInternal);
1218   while ((entry = os::readdir(dir, (dirent *) dbuf)) != NULL) {
1219     const char* name = entry->d_name;
1220     if (name[0] == '.') continue;
1221 
1222     size_t name_len = strlen(name);
1223     size_t needed = directory_len + name_len + 2;
1224     size_t new_len = path_len + needed;
1225     if (path == NULL) {
1226       path = NEW_C_HEAP_ARRAY(char, new_len, mtInternal);
1227     } else {
1228       path = REALLOC_C_HEAP_ARRAY(char, path, new_len, mtInternal);
1229     }
1230     if (path == NULL)
1231       break;
1232 
1233     // append <pathSep>directory<fileSep>name
1234     char* p = path;
1235     if (path_len > 0) {
1236       p += (path_len -1);
1237       *p = pathSep;
1238       p++;
1239     }
1240 
1241     strcpy(p, directory);
1242     p += directory_len;
1243 
1244     *p = fileSep;
1245     p++;
1246 
1247     strcpy(p, name);
1248     p += name_len;
1249 
1250     path_len = new_len;
1251   }
1252 
1253   FREE_C_HEAP_ARRAY(char, dbuf);
1254   os::closedir(dir);
1255 
1256   return path;
1257 }
1258 
1259 bool os::set_boot_path(char fileSep, char pathSep) {
1260   const char* home = Arguments::get_java_home();
1261   int home_len = (int)strlen(home);
1262 
1263   char* sysclasspath = NULL;
1264   struct stat st;
1265 
1266   // modular image if bootmodules.jimage exists
1267   char* jimage = format_boot_path("%/lib/modules/" BOOT_IMAGE_NAME, home, home_len, fileSep, pathSep);
1268   if (jimage == NULL) return false;
1269   bool has_jimage = (os::stat(jimage, &st) == 0);
1270   if (has_jimage) {
1271     Arguments::set_sysclasspath(jimage);
1272     FREE_C_HEAP_ARRAY(char, jimage);
1273     return true;
1274   }
1275   FREE_C_HEAP_ARRAY(char, jimage);
1276 
1277   // check if developer build with exploded modules
1278   char* modules_dir = format_boot_path("%/modules", home, home_len, fileSep, pathSep);
1279   if (os::stat(modules_dir, &st) == 0) {
1280     if ((st.st_mode & S_IFDIR) == S_IFDIR) {
1281       sysclasspath = expand_entries_to_path(modules_dir, fileSep, pathSep);
1282     }
1283   }
1284   FREE_C_HEAP_ARRAY(char, modules_dir);
1285 
1286   // fallback to classes
1287   if (sysclasspath == NULL)
1288     sysclasspath = format_boot_path("%/classes", home, home_len, fileSep, pathSep);
1289 
1290   if (sysclasspath == NULL) return false;
1291   Arguments::set_sysclasspath(sysclasspath);
1292   FREE_C_HEAP_ARRAY(char, sysclasspath);
1293 
1294   return true;
1295 }
1296 
1297 /*
1298  * Splits a path, based on its separator, the number of
1299  * elements is returned back in n.
1300  * It is the callers responsibility to:
1301  *   a> check the value of n, and n may be 0.
1302  *   b> ignore any empty path elements
1303  *   c> free up the data.
1304  */
1305 char** os::split_path(const char* path, int* n) {
1306   *n = 0;
1307   if (path == NULL || strlen(path) == 0) {
1308     return NULL;
1309   }
1310   const char psepchar = *os::path_separator();
1311   char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal);
1312   if (inpath == NULL) {
1313     return NULL;
1314   }
1315   strcpy(inpath, path);
1316   int count = 1;
1317   char* p = strchr(inpath, psepchar);
1318   // Get a count of elements to allocate memory
1319   while (p != NULL) {
1320     count++;
1321     p++;
1322     p = strchr(p, psepchar);
1323   }
1324   char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count, mtInternal);
1325   if (opath == NULL) {
1326     return NULL;
1327   }
1328 
1329   // do the actual splitting
1330   p = inpath;
1331   for (int i = 0 ; i < count ; i++) {
1332     size_t len = strcspn(p, os::path_separator());
1333     if (len > JVM_MAXPATHLEN) {
1334       return NULL;
1335     }
1336     // allocate the string and add terminator storage
1337     char* s  = (char*)NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
1338     if (s == NULL) {
1339       return NULL;
1340     }
1341     strncpy(s, p, len);
1342     s[len] = '\0';
1343     opath[i] = s;
1344     p += len + 1;
1345   }
1346   FREE_C_HEAP_ARRAY(char, inpath);
1347   *n = count;
1348   return opath;
1349 }
1350 
1351 void os::set_memory_serialize_page(address page) {
1352   int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64);
1353   _mem_serialize_page = (volatile int32_t *)page;
1354   // We initialize the serialization page shift count here
1355   // We assume a cache line size of 64 bytes
1356   assert(SerializePageShiftCount == count,
1357          "thread size changed, fix SerializePageShiftCount constant");
1358   set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t)));
1359 }
1360 
1361 static volatile intptr_t SerializePageLock = 0;
1362 
1363 // This method is called from signal handler when SIGSEGV occurs while the current
1364 // thread tries to store to the "read-only" memory serialize page during state
1365 // transition.
1366 void os::block_on_serialize_page_trap() {
1367   log_debug(safepoint)("Block until the serialize page permission restored");
1368 
1369   // When VMThread is holding the SerializePageLock during modifying the
1370   // access permission of the memory serialize page, the following call
1371   // will block until the permission of that page is restored to rw.
1372   // Generally, it is unsafe to manipulate locks in signal handlers, but in
1373   // this case, it's OK as the signal is synchronous and we know precisely when
1374   // it can occur.
1375   Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page");
1376   Thread::muxRelease(&SerializePageLock);
1377 }
1378 
1379 // Serialize all thread state variables
1380 void os::serialize_thread_states() {
1381   // On some platforms such as Solaris & Linux, the time duration of the page
1382   // permission restoration is observed to be much longer than expected  due to
1383   // scheduler starvation problem etc. To avoid the long synchronization
1384   // time and expensive page trap spinning, 'SerializePageLock' is used to block
1385   // the mutator thread if such case is encountered. See bug 6546278 for details.
1386   Thread::muxAcquire(&SerializePageLock, "serialize_thread_states");
1387   os::protect_memory((char *)os::get_memory_serialize_page(),
1388                      os::vm_page_size(), MEM_PROT_READ);
1389   os::protect_memory((char *)os::get_memory_serialize_page(),
1390                      os::vm_page_size(), MEM_PROT_RW);
1391   Thread::muxRelease(&SerializePageLock);
1392 }
1393 
1394 // Returns true if the current stack pointer is above the stack shadow
1395 // pages, false otherwise.
1396 
1397 bool os::stack_shadow_pages_available(Thread *thread, const methodHandle& method) {
1398   assert(StackRedPages > 0 && StackYellowPages > 0,"Sanity check");
1399   address sp = current_stack_pointer();
1400   // Check if we have StackShadowPages above the yellow zone.  This parameter
1401   // is dependent on the depth of the maximum VM call stack possible from
1402   // the handler for stack overflow.  'instanceof' in the stack overflow
1403   // handler or a println uses at least 8k stack of VM and native code
1404   // respectively.
1405   const int framesize_in_bytes =
1406     Interpreter::size_top_interpreter_activation(method()) * wordSize;
1407   int reserved_area = ((StackShadowPages + StackRedPages + StackYellowPages)
1408                       * vm_page_size()) + framesize_in_bytes;
1409   // The very lower end of the stack
1410   address stack_limit = thread->stack_base() - thread->stack_size();
1411   return (sp > (stack_limit + reserved_area));
1412 }
1413 
1414 size_t os::page_size_for_region(size_t region_size, size_t min_pages, bool must_be_aligned) {
1415   assert(min_pages > 0, "sanity");
1416   if (UseLargePages) {
1417     const size_t max_page_size = region_size / min_pages;
1418 
1419     for (size_t i = 0; _page_sizes[i] != 0; ++i) {
1420       const size_t page_size = _page_sizes[i];
1421       if (page_size <= max_page_size) {
1422         if (!must_be_aligned || is_size_aligned(region_size, page_size)) {
1423           return page_size;
1424         }
1425       }
1426     }
1427   }
1428 
1429   return vm_page_size();
1430 }
1431 
1432 size_t os::page_size_for_region_aligned(size_t region_size, size_t min_pages) {
1433   return page_size_for_region(region_size, min_pages, true);
1434 }
1435 
1436 size_t os::page_size_for_region_unaligned(size_t region_size, size_t min_pages) {
1437   return page_size_for_region(region_size, min_pages, false);
1438 }
1439 
1440 #ifndef PRODUCT
1441 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count)
1442 {
1443   if (TracePageSizes) {
1444     tty->print("%s: ", str);
1445     for (int i = 0; i < count; ++i) {
1446       tty->print(" " SIZE_FORMAT, page_sizes[i]);
1447     }
1448     tty->cr();
1449   }
1450 }
1451 
1452 void os::trace_page_sizes(const char* str, const size_t region_min_size,
1453                           const size_t region_max_size, const size_t page_size,
1454                           const char* base, const size_t size)
1455 {
1456   if (TracePageSizes) {
1457     tty->print_cr("%s:  min=" SIZE_FORMAT " max=" SIZE_FORMAT
1458                   " pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT
1459                   " size=" SIZE_FORMAT,
1460                   str, region_min_size, region_max_size,
1461                   page_size, p2i(base), size);
1462   }
1463 }
1464 #endif  // #ifndef PRODUCT
1465 
1466 // This is the working definition of a server class machine:
1467 // >= 2 physical CPU's and >=2GB of memory, with some fuzz
1468 // because the graphics memory (?) sometimes masks physical memory.
1469 // If you want to change the definition of a server class machine
1470 // on some OS or platform, e.g., >=4GB on Windows platforms,
1471 // then you'll have to parameterize this method based on that state,
1472 // as was done for logical processors here, or replicate and
1473 // specialize this method for each platform.  (Or fix os to have
1474 // some inheritance structure and use subclassing.  Sigh.)
1475 // If you want some platform to always or never behave as a server
1476 // class machine, change the setting of AlwaysActAsServerClassMachine
1477 // and NeverActAsServerClassMachine in globals*.hpp.
1478 bool os::is_server_class_machine() {
1479   // First check for the early returns
1480   if (NeverActAsServerClassMachine) {
1481     return false;
1482   }
1483   if (AlwaysActAsServerClassMachine) {
1484     return true;
1485   }
1486   // Then actually look at the machine
1487   bool         result            = false;
1488   const unsigned int    server_processors = 2;
1489   const julong server_memory     = 2UL * G;
1490   // We seem not to get our full complement of memory.
1491   //     We allow some part (1/8?) of the memory to be "missing",
1492   //     based on the sizes of DIMMs, and maybe graphics cards.
1493   const julong missing_memory   = 256UL * M;
1494 
1495   /* Is this a server class machine? */
1496   if ((os::active_processor_count() >= (int)server_processors) &&
1497       (os::physical_memory() >= (server_memory - missing_memory))) {
1498     const unsigned int logical_processors =
1499       VM_Version::logical_processors_per_package();
1500     if (logical_processors > 1) {
1501       const unsigned int physical_packages =
1502         os::active_processor_count() / logical_processors;
1503       if (physical_packages > server_processors) {
1504         result = true;
1505       }
1506     } else {
1507       result = true;
1508     }
1509   }
1510   return result;
1511 }
1512 
1513 void os::SuspendedThreadTask::run() {
1514   assert(Threads_lock->owned_by_self() || (_thread == VMThread::vm_thread()), "must have threads lock to call this");
1515   internal_do_task();
1516   _done = true;
1517 }
1518 
1519 bool os::create_stack_guard_pages(char* addr, size_t bytes) {
1520   return os::pd_create_stack_guard_pages(addr, bytes);
1521 }
1522 
1523 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint) {
1524   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1525   if (result != NULL) {
1526     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1527   }
1528 
1529   return result;
1530 }
1531 
1532 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint,
1533    MEMFLAGS flags) {
1534   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1535   if (result != NULL) {
1536     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1537     MemTracker::record_virtual_memory_type((address)result, flags);
1538   }
1539 
1540   return result;
1541 }
1542 
1543 char* os::attempt_reserve_memory_at(size_t bytes, char* addr) {
1544   char* result = pd_attempt_reserve_memory_at(bytes, addr);
1545   if (result != NULL) {
1546     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1547   }
1548   return result;
1549 }
1550 
1551 void os::split_reserved_memory(char *base, size_t size,
1552                                  size_t split, bool realloc) {
1553   pd_split_reserved_memory(base, size, split, realloc);
1554 }
1555 
1556 bool os::commit_memory(char* addr, size_t bytes, bool executable) {
1557   bool res = pd_commit_memory(addr, bytes, executable);
1558   if (res) {
1559     MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1560   }
1561   return res;
1562 }
1563 
1564 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
1565                               bool executable) {
1566   bool res = os::pd_commit_memory(addr, size, alignment_hint, executable);
1567   if (res) {
1568     MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1569   }
1570   return res;
1571 }
1572 
1573 void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable,
1574                                const char* mesg) {
1575   pd_commit_memory_or_exit(addr, bytes, executable, mesg);
1576   MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1577 }
1578 
1579 void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint,
1580                                bool executable, const char* mesg) {
1581   os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg);
1582   MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1583 }
1584 
1585 bool os::uncommit_memory(char* addr, size_t bytes) {
1586   bool res;
1587   if (MemTracker::tracking_level() > NMT_minimal) {
1588     Tracker tkr = MemTracker::get_virtual_memory_uncommit_tracker();
1589     res = pd_uncommit_memory(addr, bytes);
1590     if (res) {
1591       tkr.record((address)addr, bytes);
1592     }
1593   } else {
1594     res = pd_uncommit_memory(addr, bytes);
1595   }
1596   return res;
1597 }
1598 
1599 bool os::release_memory(char* addr, size_t bytes) {
1600   bool res;
1601   if (MemTracker::tracking_level() > NMT_minimal) {
1602     Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1603     res = pd_release_memory(addr, bytes);
1604     if (res) {
1605       tkr.record((address)addr, bytes);
1606     }
1607   } else {
1608     res = pd_release_memory(addr, bytes);
1609   }
1610   return res;
1611 }
1612 
1613 void os::pretouch_memory(char* start, char* end) {
1614   for (volatile char *p = start; p < end; p += os::vm_page_size()) {
1615     *p = 0;
1616   }
1617 }
1618 
1619 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
1620                            char *addr, size_t bytes, bool read_only,
1621                            bool allow_exec) {
1622   char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec);
1623   if (result != NULL) {
1624     MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1625   }
1626   return result;
1627 }
1628 
1629 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
1630                              char *addr, size_t bytes, bool read_only,
1631                              bool allow_exec) {
1632   return pd_remap_memory(fd, file_name, file_offset, addr, bytes,
1633                     read_only, allow_exec);
1634 }
1635 
1636 bool os::unmap_memory(char *addr, size_t bytes) {
1637   bool result;
1638   if (MemTracker::tracking_level() > NMT_minimal) {
1639     Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1640     result = pd_unmap_memory(addr, bytes);
1641     if (result) {
1642       tkr.record((address)addr, bytes);
1643     }
1644   } else {
1645     result = pd_unmap_memory(addr, bytes);
1646   }
1647   return result;
1648 }
1649 
1650 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
1651   pd_free_memory(addr, bytes, alignment_hint);
1652 }
1653 
1654 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
1655   pd_realign_memory(addr, bytes, alignment_hint);
1656 }
1657 
1658 #ifndef TARGET_OS_FAMILY_windows
1659 /* try to switch state from state "from" to state "to"
1660  * returns the state set after the method is complete
1661  */
1662 os::SuspendResume::State os::SuspendResume::switch_state(os::SuspendResume::State from,
1663                                                          os::SuspendResume::State to)
1664 {
1665   os::SuspendResume::State result =
1666     (os::SuspendResume::State) Atomic::cmpxchg((jint) to, (jint *) &_state, (jint) from);
1667   if (result == from) {
1668     // success
1669     return to;
1670   }
1671   return result;
1672 }
1673 #endif
1674 
1675 /////////////// Unit tests ///////////////
1676 
1677 #ifndef PRODUCT
1678 
1679 #define assert_eq(a,b) assert(a == b, SIZE_FORMAT " != " SIZE_FORMAT, a, b)
1680 
1681 class TestOS : AllStatic {
1682   static size_t small_page_size() {
1683     return os::vm_page_size();
1684   }
1685 
1686   static size_t large_page_size() {
1687     const size_t large_page_size_example = 4 * M;
1688     return os::page_size_for_region_aligned(large_page_size_example, 1);
1689   }
1690 
1691   static void test_page_size_for_region_aligned() {
1692     if (UseLargePages) {
1693       const size_t small_page = small_page_size();
1694       const size_t large_page = large_page_size();
1695 
1696       if (large_page > small_page) {
1697         size_t num_small_pages_in_large = large_page / small_page;
1698         size_t page = os::page_size_for_region_aligned(large_page, num_small_pages_in_large);
1699 
1700         assert_eq(page, small_page);
1701       }
1702     }
1703   }
1704 
1705   static void test_page_size_for_region_alignment() {
1706     if (UseLargePages) {
1707       const size_t small_page = small_page_size();
1708       const size_t large_page = large_page_size();
1709       if (large_page > small_page) {
1710         const size_t unaligned_region = large_page + 17;
1711         size_t page = os::page_size_for_region_aligned(unaligned_region, 1);
1712         assert_eq(page, small_page);
1713 
1714         const size_t num_pages = 5;
1715         const size_t aligned_region = large_page * num_pages;
1716         page = os::page_size_for_region_aligned(aligned_region, num_pages);
1717         assert_eq(page, large_page);
1718       }
1719     }
1720   }
1721 
1722   static void test_page_size_for_region_unaligned() {
1723     if (UseLargePages) {
1724       // Given exact page size, should return that page size.
1725       for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
1726         size_t expected = os::_page_sizes[i];
1727         size_t actual = os::page_size_for_region_unaligned(expected, 1);
1728         assert_eq(expected, actual);
1729       }
1730 
1731       // Given slightly larger size than a page size, return the page size.
1732       for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
1733         size_t expected = os::_page_sizes[i];
1734         size_t actual = os::page_size_for_region_unaligned(expected + 17, 1);
1735         assert_eq(expected, actual);
1736       }
1737 
1738       // Given a slightly smaller size than a page size,
1739       // return the next smaller page size.
1740       if (os::_page_sizes[1] > os::_page_sizes[0]) {
1741         size_t expected = os::_page_sizes[0];
1742         size_t actual = os::page_size_for_region_unaligned(os::_page_sizes[1] - 17, 1);
1743         assert_eq(actual, expected);
1744       }
1745 
1746       // Return small page size for values less than a small page.
1747       size_t small_page = small_page_size();
1748       size_t actual = os::page_size_for_region_unaligned(small_page - 17, 1);
1749       assert_eq(small_page, actual);
1750     }
1751   }
1752 
1753  public:
1754   static void run_tests() {
1755     test_page_size_for_region_aligned();
1756     test_page_size_for_region_alignment();
1757     test_page_size_for_region_unaligned();
1758   }
1759 };
1760 
1761 void TestOS_test() {
1762   TestOS::run_tests();
1763 }
1764 
1765 #endif // PRODUCT
--- EOF ---