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(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   // VM version initialization identifies some characteristics of the
 320   // the platform that are used during ergonomic decisions.
 321   VM_Version::init_before_ergo();
 322 }
 323 
 324 void os::signal_init() {
 325   if (!ReduceSignalUsage) {
 326     // Setup JavaThread for processing signals
 327     EXCEPTION_MARK;
 328     Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
 329     instanceKlassHandle klass (THREAD, k);
 330     instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
 331 
 332     const char thread_name[] = "Signal Dispatcher";
 333     Handle string = java_lang_String::create_from_str(thread_name, CHECK);
 334 
 335     // Initialize thread_oop to put it into the system threadGroup
 336     Handle thread_group (THREAD, Universe::system_thread_group());
 337     JavaValue result(T_VOID);
 338     JavaCalls::call_special(&result, thread_oop,
 339                            klass,
 340                            vmSymbols::object_initializer_name(),
 341                            vmSymbols::threadgroup_string_void_signature(),
 342                            thread_group,
 343                            string,
 344                            CHECK);
 345 
 346     KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
 347     JavaCalls::call_special(&result,
 348                             thread_group,
 349                             group,
 350                             vmSymbols::add_method_name(),
 351                             vmSymbols::thread_void_signature(),
 352                             thread_oop,         // ARG 1
 353                             CHECK);
 354 
 355     os::signal_init_pd();
 356 
 357     { MutexLocker mu(Threads_lock);
 358       JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
 359 
 360       // At this point it may be possible that no osthread was created for the
 361       // JavaThread due to lack of memory. We would have to throw an exception
 362       // in that case. However, since this must work and we do not allow
 363       // exceptions anyway, check and abort if this fails.
 364       if (signal_thread == NULL || signal_thread->osthread() == NULL) {
 365         vm_exit_during_initialization("java.lang.OutOfMemoryError",
 366                                       os::native_thread_creation_failed_msg());
 367       }
 368 
 369       java_lang_Thread::set_thread(thread_oop(), signal_thread);
 370       java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
 371       java_lang_Thread::set_daemon(thread_oop());
 372 
 373       signal_thread->set_threadObj(thread_oop());
 374       Threads::add(signal_thread);
 375       Thread::start(signal_thread);
 376     }
 377     // Handle ^BREAK
 378     os::signal(SIGBREAK, os::user_handler());
 379   }
 380 }
 381 
 382 
 383 void os::terminate_signal_thread() {
 384   if (!ReduceSignalUsage)
 385     signal_notify(sigexitnum_pd());
 386 }
 387 
 388 
 389 // --------------------- loading libraries ---------------------
 390 
 391 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
 392 extern struct JavaVM_ main_vm;
 393 
 394 static void* _native_java_library = NULL;
 395 
 396 void* os::native_java_library() {
 397   if (_native_java_library == NULL) {
 398     char buffer[JVM_MAXPATHLEN];
 399     char ebuf[1024];
 400 
 401     // Try to load verify dll first. In 1.3 java dll depends on it and is not
 402     // always able to find it when the loading executable is outside the JDK.
 403     // In order to keep working with 1.2 we ignore any loading errors.
 404     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 405                        "verify")) {
 406       dll_load(buffer, ebuf, sizeof(ebuf));
 407     }
 408 
 409     // Load java dll
 410     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 411                        "java")) {
 412       _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
 413     }
 414     if (_native_java_library == NULL) {
 415       vm_exit_during_initialization("Unable to load native library", ebuf);
 416     }
 417 
 418 #if defined(__OpenBSD__)
 419     // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so
 420     // ignore errors
 421     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 422                        "net")) {
 423       dll_load(buffer, ebuf, sizeof(ebuf));
 424     }
 425 #endif
 426   }
 427   return _native_java_library;
 428 }
 429 
 430 /*
 431  * Support for finding Agent_On(Un)Load/Attach<_lib_name> if it exists.
 432  * If check_lib == true then we are looking for an
 433  * Agent_OnLoad_lib_name or Agent_OnAttach_lib_name function to determine if
 434  * this library is statically linked into the image.
 435  * If check_lib == false then we will look for the appropriate symbol in the
 436  * executable if agent_lib->is_static_lib() == true or in the shared library
 437  * referenced by 'handle'.
 438  */
 439 void* os::find_agent_function(AgentLibrary *agent_lib, bool check_lib,
 440                               const char *syms[], size_t syms_len) {
 441   assert(agent_lib != NULL, "sanity check");
 442   const char *lib_name;
 443   void *handle = agent_lib->os_lib();
 444   void *entryName = NULL;
 445   char *agent_function_name;
 446   size_t i;
 447 
 448   // If checking then use the agent name otherwise test is_static_lib() to
 449   // see how to process this lookup
 450   lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : NULL);
 451   for (i = 0; i < syms_len; i++) {
 452     agent_function_name = build_agent_function_name(syms[i], lib_name, agent_lib->is_absolute_path());
 453     if (agent_function_name == NULL) {
 454       break;
 455     }
 456     entryName = dll_lookup(handle, agent_function_name);
 457     FREE_C_HEAP_ARRAY(char, agent_function_name);
 458     if (entryName != NULL) {
 459       break;
 460     }
 461   }
 462   return entryName;
 463 }
 464 
 465 // See if the passed in agent is statically linked into the VM image.
 466 bool os::find_builtin_agent(AgentLibrary *agent_lib, const char *syms[],
 467                             size_t syms_len) {
 468   void *ret;
 469   void *proc_handle;
 470   void *save_handle;
 471 
 472   assert(agent_lib != NULL, "sanity check");
 473   if (agent_lib->name() == NULL) {
 474     return false;
 475   }
 476   proc_handle = get_default_process_handle();
 477   // Check for Agent_OnLoad/Attach_lib_name function
 478   save_handle = agent_lib->os_lib();
 479   // We want to look in this process' symbol table.
 480   agent_lib->set_os_lib(proc_handle);
 481   ret = find_agent_function(agent_lib, true, syms, syms_len);
 482   if (ret != NULL) {
 483     // Found an entry point like Agent_OnLoad_lib_name so we have a static agent
 484     agent_lib->set_valid();
 485     agent_lib->set_static_lib(true);
 486     return true;
 487   }
 488   agent_lib->set_os_lib(save_handle);
 489   return false;
 490 }
 491 
 492 // --------------------- heap allocation utilities ---------------------
 493 
 494 char *os::strdup(const char *str, MEMFLAGS flags) {
 495   size_t size = strlen(str);
 496   char *dup_str = (char *)malloc(size + 1, flags);
 497   if (dup_str == NULL) return NULL;
 498   strcpy(dup_str, str);
 499   return dup_str;
 500 }
 501 
 502 char* os::strdup_check_oom(const char* str, MEMFLAGS flags) {
 503   char* p = os::strdup(str, flags);
 504   if (p == NULL) {
 505     vm_exit_out_of_memory(strlen(str) + 1, OOM_MALLOC_ERROR, "os::strdup_check_oom");
 506   }
 507   return p;
 508 }
 509 
 510 
 511 #define paranoid                 0  /* only set to 1 if you suspect checking code has bug */
 512 
 513 #ifdef ASSERT
 514 
 515 static void verify_memory(void* ptr) {
 516   GuardedMemory guarded(ptr);
 517   if (!guarded.verify_guards()) {
 518     tty->print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees);
 519     tty->print_cr("## memory stomp:");
 520     guarded.print_on(tty);
 521     fatal("memory stomping error");
 522   }
 523 }
 524 
 525 #endif
 526 
 527 //
 528 // This function supports testing of the malloc out of memory
 529 // condition without really running the system out of memory.
 530 //
 531 static bool has_reached_max_malloc_test_peak(size_t alloc_size) {
 532   if (MallocMaxTestWords > 0) {
 533     jint words = (jint)(alloc_size / BytesPerWord);
 534 
 535     if ((cur_malloc_words + words) > MallocMaxTestWords) {
 536       return true;
 537     }
 538     Atomic::add(words, (volatile jint *)&cur_malloc_words);
 539   }
 540   return false;
 541 }
 542 
 543 void* os::malloc(size_t size, MEMFLAGS flags) {
 544   return os::malloc(size, flags, CALLER_PC);
 545 }
 546 
 547 void* os::malloc(size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
 548   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 549   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 550 
 551 #ifdef ASSERT
 552   // checking for the WatcherThread and crash_protection first
 553   // since os::malloc can be called when the libjvm.{dll,so} is
 554   // first loaded and we don't have a thread yet.
 555   // try to find the thread after we see that the watcher thread
 556   // exists and has crash protection.
 557   WatcherThread *wt = WatcherThread::watcher_thread();
 558   if (wt != NULL && wt->has_crash_protection()) {
 559     Thread* thread = Thread::current_or_null();
 560     if (thread == wt) {
 561       assert(!wt->has_crash_protection(),
 562           "Can't malloc with crash protection from WatcherThread");
 563     }
 564   }
 565 #endif
 566 
 567   if (size == 0) {
 568     // return a valid pointer if size is zero
 569     // if NULL is returned the calling functions assume out of memory.
 570     size = 1;
 571   }
 572 
 573   // NMT support
 574   NMT_TrackingLevel level = MemTracker::tracking_level();
 575   size_t            nmt_header_size = MemTracker::malloc_header_size(level);
 576 
 577 #ifndef ASSERT
 578   const size_t alloc_size = size + nmt_header_size;
 579 #else
 580   const size_t alloc_size = GuardedMemory::get_total_size(size + nmt_header_size);
 581   if (size + nmt_header_size > alloc_size) { // Check for rollover.
 582     return NULL;
 583   }
 584 #endif
 585 
 586   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 587 
 588   // For the test flag -XX:MallocMaxTestWords
 589   if (has_reached_max_malloc_test_peak(size)) {
 590     return NULL;
 591   }
 592 
 593   u_char* ptr;
 594   ptr = (u_char*)::malloc(alloc_size);
 595 
 596 #ifdef ASSERT
 597   if (ptr == NULL) {
 598     return NULL;
 599   }
 600   // Wrap memory with guard
 601   GuardedMemory guarded(ptr, size + nmt_header_size);
 602   ptr = guarded.get_user_ptr();
 603 #endif
 604   if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
 605     tty->print_cr("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
 606     breakpoint();
 607   }
 608   debug_only(if (paranoid) verify_memory(ptr));
 609   if (PrintMalloc && tty != NULL) {
 610     tty->print_cr("os::malloc " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
 611   }
 612 
 613   // we do not track guard memory
 614   return MemTracker::record_malloc((address)ptr, size, memflags, stack, level);
 615 }
 616 
 617 void* os::realloc(void *memblock, size_t size, MEMFLAGS flags) {
 618   return os::realloc(memblock, size, flags, CALLER_PC);
 619 }
 620 
 621 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
 622 
 623   // For the test flag -XX:MallocMaxTestWords
 624   if (has_reached_max_malloc_test_peak(size)) {
 625     return NULL;
 626   }
 627 
 628 #ifndef ASSERT
 629   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 630   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 631    // NMT support
 632   void* membase = MemTracker::record_free(memblock);
 633   NMT_TrackingLevel level = MemTracker::tracking_level();
 634   size_t  nmt_header_size = MemTracker::malloc_header_size(level);
 635   void* ptr = ::realloc(membase, size + nmt_header_size);
 636   return MemTracker::record_malloc(ptr, size, memflags, stack, level);
 637 #else
 638   if (memblock == NULL) {
 639     return os::malloc(size, memflags, stack);
 640   }
 641   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 642     tty->print_cr("os::realloc caught " PTR_FORMAT, p2i(memblock));
 643     breakpoint();
 644   }
 645   // NMT support
 646   void* membase = MemTracker::malloc_base(memblock);
 647   verify_memory(membase);
 648   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 649   if (size == 0) {
 650     return NULL;
 651   }
 652   // always move the block
 653   void* ptr = os::malloc(size, memflags, stack);
 654   if (PrintMalloc && tty != NULL) {
 655     tty->print_cr("os::realloc " SIZE_FORMAT " bytes, " PTR_FORMAT " --> " PTR_FORMAT, size, p2i(memblock), p2i(ptr));
 656   }
 657   // Copy to new memory if malloc didn't fail
 658   if ( ptr != NULL ) {
 659     GuardedMemory guarded(MemTracker::malloc_base(memblock));
 660     // Guard's user data contains NMT header
 661     size_t memblock_size = guarded.get_user_size() - MemTracker::malloc_header_size(memblock);
 662     memcpy(ptr, memblock, MIN2(size, memblock_size));
 663     if (paranoid) verify_memory(MemTracker::malloc_base(ptr));
 664     if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
 665       tty->print_cr("os::realloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
 666       breakpoint();
 667     }
 668     os::free(memblock);
 669   }
 670   return ptr;
 671 #endif
 672 }
 673 
 674 
 675 void  os::free(void *memblock) {
 676   NOT_PRODUCT(inc_stat_counter(&num_frees, 1));
 677 #ifdef ASSERT
 678   if (memblock == NULL) return;
 679   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 680     if (tty != NULL) tty->print_cr("os::free caught " PTR_FORMAT, p2i(memblock));
 681     breakpoint();
 682   }
 683   void* membase = MemTracker::record_free(memblock);
 684   verify_memory(membase);
 685   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 686 
 687   GuardedMemory guarded(membase);
 688   size_t size = guarded.get_user_size();
 689   inc_stat_counter(&free_bytes, size);
 690   membase = guarded.release_for_freeing();
 691   if (PrintMalloc && tty != NULL) {
 692       fprintf(stderr, "os::free " SIZE_FORMAT " bytes --> " PTR_FORMAT "\n", size, (uintptr_t)membase);
 693   }
 694   ::free(membase);
 695 #else
 696   void* membase = MemTracker::record_free(memblock);
 697   ::free(membase);
 698 #endif
 699 }
 700 
 701 void os::init_random(long initval) {
 702   _rand_seed = initval;
 703 }
 704 
 705 
 706 long os::random() {
 707   /* standard, well-known linear congruential random generator with
 708    * next_rand = (16807*seed) mod (2**31-1)
 709    * see
 710    * (1) "Random Number Generators: Good Ones Are Hard to Find",
 711    *      S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
 712    * (2) "Two Fast Implementations of the 'Minimal Standard' Random
 713    *     Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
 714   */
 715   const long a = 16807;
 716   const unsigned long m = 2147483647;
 717   const long q = m / a;        assert(q == 127773, "weird math");
 718   const long r = m % a;        assert(r == 2836, "weird math");
 719 
 720   // compute az=2^31p+q
 721   unsigned long lo = a * (long)(_rand_seed & 0xFFFF);
 722   unsigned long hi = a * (long)((unsigned long)_rand_seed >> 16);
 723   lo += (hi & 0x7FFF) << 16;
 724 
 725   // if q overflowed, ignore the overflow and increment q
 726   if (lo > m) {
 727     lo &= m;
 728     ++lo;
 729   }
 730   lo += hi >> 15;
 731 
 732   // if (p+q) overflowed, ignore the overflow and increment (p+q)
 733   if (lo > m) {
 734     lo &= m;
 735     ++lo;
 736   }
 737   return (_rand_seed = lo);
 738 }
 739 
 740 // The INITIALIZED state is distinguished from the SUSPENDED state because the
 741 // conditions in which a thread is first started are different from those in which
 742 // a suspension is resumed.  These differences make it hard for us to apply the
 743 // tougher checks when starting threads that we want to do when resuming them.
 744 // However, when start_thread is called as a result of Thread.start, on a Java
 745 // thread, the operation is synchronized on the Java Thread object.  So there
 746 // cannot be a race to start the thread and hence for the thread to exit while
 747 // we are working on it.  Non-Java threads that start Java threads either have
 748 // to do so in a context in which races are impossible, or should do appropriate
 749 // locking.
 750 
 751 void os::start_thread(Thread* thread) {
 752   // guard suspend/resume
 753   MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
 754   OSThread* osthread = thread->osthread();
 755   osthread->set_state(RUNNABLE);
 756   pd_start_thread(thread);
 757 }
 758 
 759 void os::abort(bool dump_core) {
 760   abort(dump_core && CreateCoredumpOnCrash, NULL, NULL);
 761 }
 762 
 763 //---------------------------------------------------------------------------
 764 // Helper functions for fatal error handler
 765 
 766 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
 767   assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
 768 
 769   int cols = 0;
 770   int cols_per_line = 0;
 771   switch (unitsize) {
 772     case 1: cols_per_line = 16; break;
 773     case 2: cols_per_line = 8;  break;
 774     case 4: cols_per_line = 4;  break;
 775     case 8: cols_per_line = 2;  break;
 776     default: return;
 777   }
 778 
 779   address p = start;
 780   st->print(PTR_FORMAT ":   ", p2i(start));
 781   while (p < end) {
 782     switch (unitsize) {
 783       case 1: st->print("%02x", *(u1*)p); break;
 784       case 2: st->print("%04x", *(u2*)p); break;
 785       case 4: st->print("%08x", *(u4*)p); break;
 786       case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
 787     }
 788     p += unitsize;
 789     cols++;
 790     if (cols >= cols_per_line && p < end) {
 791        cols = 0;
 792        st->cr();
 793        st->print(PTR_FORMAT ":   ", p2i(p));
 794     } else {
 795        st->print(" ");
 796     }
 797   }
 798   st->cr();
 799 }
 800 
 801 void os::print_environment_variables(outputStream* st, const char** env_list) {
 802   if (env_list) {
 803     st->print_cr("Environment Variables:");
 804 
 805     for (int i = 0; env_list[i] != NULL; i++) {
 806       char *envvar = ::getenv(env_list[i]);
 807       if (envvar != NULL) {
 808         st->print("%s", env_list[i]);
 809         st->print("=");
 810         st->print_cr("%s", envvar);
 811       }
 812     }
 813   }
 814 }
 815 
 816 void os::print_cpu_info(outputStream* st, char* buf, size_t buflen) {
 817   // cpu
 818   st->print("CPU:");
 819   st->print("total %d", os::processor_count());
 820   // It's not safe to query number of active processors after crash
 821   // st->print("(active %d)", os::active_processor_count());
 822   st->print(" %s", VM_Version::cpu_features());
 823   st->cr();
 824   pd_print_cpu_info(st, buf, buflen);
 825 }
 826 
 827 // Print a one line string summarizing the cpu, number of cores, memory, and operating system version
 828 void os::print_summary_info(outputStream* st, char* buf, size_t buflen) {
 829   st->print("Host: ");
 830 #ifndef PRODUCT
 831   if (get_host_name(buf, buflen)) {
 832     st->print("%s, ", buf);
 833   }
 834 #endif // PRODUCT
 835   get_summary_cpu_info(buf, buflen);
 836   st->print("%s, ", buf);
 837   size_t mem = physical_memory()/G;
 838   if (mem == 0) {  // for low memory systems
 839     mem = physical_memory()/M;
 840     st->print("%d cores, " SIZE_FORMAT "M, ", processor_count(), mem);
 841   } else {
 842     st->print("%d cores, " SIZE_FORMAT "G, ", processor_count(), mem);
 843   }
 844   get_summary_os_info(buf, buflen);
 845   st->print_raw(buf);
 846   st->cr();
 847 }
 848 
 849 void os::print_date_and_time(outputStream *st, char* buf, size_t buflen) {
 850   const int secs_per_day  = 86400;
 851   const int secs_per_hour = 3600;
 852   const int secs_per_min  = 60;
 853 
 854   time_t tloc;
 855   (void)time(&tloc);
 856   char* timestring = ctime(&tloc);  // ctime adds newline.
 857   // edit out the newline
 858   char* nl = strchr(timestring, '\n');
 859   if (nl != NULL) {
 860     *nl = '\0';
 861   }
 862 
 863   struct tm tz;
 864   if (localtime_pd(&tloc, &tz) != NULL) {
 865     ::strftime(buf, buflen, "%Z", &tz);
 866     st->print("Time: %s %s", timestring, buf);
 867   } else {
 868     st->print("Time: %s", timestring);
 869   }
 870 
 871   double t = os::elapsedTime();
 872   // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
 873   //       Linux. Must be a bug in glibc ? Workaround is to round "t" to int
 874   //       before printf. We lost some precision, but who cares?
 875   int eltime = (int)t;  // elapsed time in seconds
 876 
 877   // print elapsed time in a human-readable format:
 878   int eldays = eltime / secs_per_day;
 879   int day_secs = eldays * secs_per_day;
 880   int elhours = (eltime - day_secs) / secs_per_hour;
 881   int hour_secs = elhours * secs_per_hour;
 882   int elmins = (eltime - day_secs - hour_secs) / secs_per_min;
 883   int minute_secs = elmins * secs_per_min;
 884   int elsecs = (eltime - day_secs - hour_secs - minute_secs);
 885   st->print_cr(" elapsed time: %d seconds (%dd %dh %dm %ds)", eltime, eldays, elhours, elmins, elsecs);
 886 }
 887 
 888 // moved from debug.cpp (used to be find()) but still called from there
 889 // The verbose parameter is only set by the debug code in one case
 890 void os::print_location(outputStream* st, intptr_t x, bool verbose) {
 891   address addr = (address)x;
 892   CodeBlob* b = CodeCache::find_blob_unsafe(addr);
 893   if (b != NULL) {
 894     if (b->is_buffer_blob()) {
 895       // the interpreter is generated into a buffer blob
 896       InterpreterCodelet* i = Interpreter::codelet_containing(addr);
 897       if (i != NULL) {
 898         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an Interpreter codelet", p2i(addr), (int)(addr - i->code_begin()));
 899         i->print_on(st);
 900         return;
 901       }
 902       if (Interpreter::contains(addr)) {
 903         st->print_cr(INTPTR_FORMAT " is pointing into interpreter code"
 904                      " (not bytecode specific)", p2i(addr));
 905         return;
 906       }
 907       //
 908       if (AdapterHandlerLibrary::contains(b)) {
 909         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an AdapterHandler", p2i(addr), (int)(addr - b->code_begin()));
 910         AdapterHandlerLibrary::print_handler_on(st, b);
 911       }
 912       // the stubroutines are generated into a buffer blob
 913       StubCodeDesc* d = StubCodeDesc::desc_for(addr);
 914       if (d != NULL) {
 915         st->print_cr(INTPTR_FORMAT " is at begin+%d in a stub", p2i(addr), (int)(addr - d->begin()));
 916         d->print_on(st);
 917         st->cr();
 918         return;
 919       }
 920       if (StubRoutines::contains(addr)) {
 921         st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) stub routine", p2i(addr));
 922         return;
 923       }
 924       // the InlineCacheBuffer is using stubs generated into a buffer blob
 925       if (InlineCacheBuffer::contains(addr)) {
 926         st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", p2i(addr));
 927         return;
 928       }
 929       VtableStub* v = VtableStubs::stub_containing(addr);
 930       if (v != NULL) {
 931         st->print_cr(INTPTR_FORMAT " is at entry_point+%d in a vtable stub", p2i(addr), (int)(addr - v->entry_point()));
 932         v->print_on(st);
 933         st->cr();
 934         return;
 935       }
 936     }
 937     nmethod* nm = b->as_nmethod_or_null();
 938     if (nm != NULL) {
 939       ResourceMark rm;
 940       st->print(INTPTR_FORMAT " is at entry_point+%d in (nmethod*)" INTPTR_FORMAT,
 941                 p2i(addr), (int)(addr - nm->entry_point()), p2i(nm));
 942       if (verbose) {
 943         st->print(" for ");
 944         nm->method()->print_value_on(st);
 945       }
 946       st->cr();
 947       nm->print_nmethod(verbose);
 948       return;
 949     }
 950     st->print_cr(INTPTR_FORMAT " is at code_begin+%d in ", p2i(addr), (int)(addr - b->code_begin()));
 951     b->print_on(st);
 952     return;
 953   }
 954 
 955   if (Universe::heap()->is_in(addr)) {
 956     HeapWord* p = Universe::heap()->block_start(addr);
 957     bool print = false;
 958     // If we couldn't find it it just may mean that heap wasn't parsable
 959     // See if we were just given an oop directly
 960     if (p != NULL && Universe::heap()->block_is_obj(p)) {
 961       print = true;
 962     } else if (p == NULL && ((oopDesc*)addr)->is_oop()) {
 963       p = (HeapWord*) addr;
 964       print = true;
 965     }
 966     if (print) {
 967       if (p == (HeapWord*) addr) {
 968         st->print_cr(INTPTR_FORMAT " is an oop", p2i(addr));
 969       } else {
 970         st->print_cr(INTPTR_FORMAT " is pointing into object: " INTPTR_FORMAT, p2i(addr), p2i(p));
 971       }
 972       oop(p)->print_on(st);
 973       return;
 974     }
 975   } else {
 976     if (Universe::heap()->is_in_reserved(addr)) {
 977       st->print_cr(INTPTR_FORMAT " is an unallocated location "
 978                    "in the heap", p2i(addr));
 979       return;
 980     }
 981   }
 982   if (JNIHandles::is_global_handle((jobject) addr)) {
 983     st->print_cr(INTPTR_FORMAT " is a global jni handle", p2i(addr));
 984     return;
 985   }
 986   if (JNIHandles::is_weak_global_handle((jobject) addr)) {
 987     st->print_cr(INTPTR_FORMAT " is a weak global jni handle", p2i(addr));
 988     return;
 989   }
 990 #ifndef PRODUCT
 991   // we don't keep the block list in product mode
 992   if (JNIHandleBlock::any_contains((jobject) addr)) {
 993     st->print_cr(INTPTR_FORMAT " is a local jni handle", p2i(addr));
 994     return;
 995   }
 996 #endif
 997 
 998   for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
 999     // Check for privilege stack
1000     if (thread->privileged_stack_top() != NULL &&
1001         thread->privileged_stack_top()->contains(addr)) {
1002       st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack "
1003                    "for thread: " INTPTR_FORMAT, p2i(addr), p2i(thread));
1004       if (verbose) thread->print_on(st);
1005       return;
1006     }
1007     // If the addr is a java thread print information about that.
1008     if (addr == (address)thread) {
1009       if (verbose) {
1010         thread->print_on(st);
1011       } else {
1012         st->print_cr(INTPTR_FORMAT " is a thread", p2i(addr));
1013       }
1014       return;
1015     }
1016     // If the addr is in the stack region for this thread then report that
1017     // and print thread info
1018     if (thread->stack_base() >= addr &&
1019         addr > (thread->stack_base() - thread->stack_size())) {
1020       st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
1021                    INTPTR_FORMAT, p2i(addr), p2i(thread));
1022       if (verbose) thread->print_on(st);
1023       return;
1024     }
1025 
1026   }
1027 
1028   // Check if in metaspace and print types that have vptrs (only method now)
1029   if (Metaspace::contains(addr)) {
1030     if (Method::has_method_vptr((const void*)addr)) {
1031       ((Method*)addr)->print_value_on(st);
1032       st->cr();
1033     } else {
1034       // Use addr->print() from the debugger instead (not here)
1035       st->print_cr(INTPTR_FORMAT " is pointing into metadata", p2i(addr));
1036     }
1037     return;
1038   }
1039 
1040   // Try an OS specific find
1041   if (os::find(addr, st)) {
1042     return;
1043   }
1044 
1045   st->print_cr(INTPTR_FORMAT " is an unknown value", p2i(addr));
1046 }
1047 
1048 // Looks like all platforms except IA64 can use the same function to check
1049 // if C stack is walkable beyond current frame. The check for fp() is not
1050 // necessary on Sparc, but it's harmless.
1051 bool os::is_first_C_frame(frame* fr) {
1052 #if (defined(IA64) && !defined(AIX)) && !defined(_WIN32)
1053   // On IA64 we have to check if the callers bsp is still valid
1054   // (i.e. within the register stack bounds).
1055   // Notice: this only works for threads created by the VM and only if
1056   // we walk the current stack!!! If we want to be able to walk
1057   // arbitrary other threads, we'll have to somehow store the thread
1058   // object in the frame.
1059   Thread *thread = Thread::current();
1060   if ((address)fr->fp() <=
1061       thread->register_stack_base() HPUX_ONLY(+ 0x0) LINUX_ONLY(+ 0x50)) {
1062     // This check is a little hacky, because on Linux the first C
1063     // frame's ('start_thread') register stack frame starts at
1064     // "register_stack_base + 0x48" while on HPUX, the first C frame's
1065     // ('__pthread_bound_body') register stack frame seems to really
1066     // start at "register_stack_base".
1067     return true;
1068   } else {
1069     return false;
1070   }
1071 #elif defined(IA64) && defined(_WIN32)
1072   return true;
1073 #else
1074   // Load up sp, fp, sender sp and sender fp, check for reasonable values.
1075   // Check usp first, because if that's bad the other accessors may fault
1076   // on some architectures.  Ditto ufp second, etc.
1077   uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
1078   // sp on amd can be 32 bit aligned.
1079   uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
1080 
1081   uintptr_t usp    = (uintptr_t)fr->sp();
1082   if ((usp & sp_align_mask) != 0) return true;
1083 
1084   uintptr_t ufp    = (uintptr_t)fr->fp();
1085   if ((ufp & fp_align_mask) != 0) return true;
1086 
1087   uintptr_t old_sp = (uintptr_t)fr->sender_sp();
1088   if ((old_sp & sp_align_mask) != 0) return true;
1089   if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
1090 
1091   uintptr_t old_fp = (uintptr_t)fr->link();
1092   if ((old_fp & fp_align_mask) != 0) return true;
1093   if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
1094 
1095   // stack grows downwards; if old_fp is below current fp or if the stack
1096   // frame is too large, either the stack is corrupted or fp is not saved
1097   // on stack (i.e. on x86, ebp may be used as general register). The stack
1098   // is not walkable beyond current frame.
1099   if (old_fp < ufp) return true;
1100   if (old_fp - ufp > 64 * K) return true;
1101 
1102   return false;
1103 #endif
1104 }
1105 
1106 #ifdef ASSERT
1107 extern "C" void test_random() {
1108   const double m = 2147483647;
1109   double mean = 0.0, variance = 0.0, t;
1110   long reps = 10000;
1111   unsigned long seed = 1;
1112 
1113   tty->print_cr("seed %ld for %ld repeats...", seed, reps);
1114   os::init_random(seed);
1115   long num;
1116   for (int k = 0; k < reps; k++) {
1117     num = os::random();
1118     double u = (double)num / m;
1119     assert(u >= 0.0 && u <= 1.0, "bad random number!");
1120 
1121     // calculate mean and variance of the random sequence
1122     mean += u;
1123     variance += (u*u);
1124   }
1125   mean /= reps;
1126   variance /= (reps - 1);
1127 
1128   assert(num == 1043618065, "bad seed");
1129   tty->print_cr("mean of the 1st 10000 numbers: %f", mean);
1130   tty->print_cr("variance of the 1st 10000 numbers: %f", variance);
1131   const double eps = 0.0001;
1132   t = fabsd(mean - 0.5018);
1133   assert(t < eps, "bad mean");
1134   t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355;
1135   assert(t < eps, "bad variance");
1136 }
1137 #endif
1138 
1139 
1140 // Set up the boot classpath.
1141 
1142 char* os::format_boot_path(const char* format_string,
1143                            const char* home,
1144                            int home_len,
1145                            char fileSep,
1146                            char pathSep) {
1147     assert((fileSep == '/' && pathSep == ':') ||
1148            (fileSep == '\\' && pathSep == ';'), "unexpected separator chars");
1149 
1150     // Scan the format string to determine the length of the actual
1151     // boot classpath, and handle platform dependencies as well.
1152     int formatted_path_len = 0;
1153     const char* p;
1154     for (p = format_string; *p != 0; ++p) {
1155         if (*p == '%') formatted_path_len += home_len - 1;
1156         ++formatted_path_len;
1157     }
1158 
1159     char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal);
1160     if (formatted_path == NULL) {
1161         return NULL;
1162     }
1163 
1164     // Create boot classpath from format, substituting separator chars and
1165     // java home directory.
1166     char* q = formatted_path;
1167     for (p = format_string; *p != 0; ++p) {
1168         switch (*p) {
1169         case '%':
1170             strcpy(q, home);
1171             q += home_len;
1172             break;
1173         case '/':
1174             *q++ = fileSep;
1175             break;
1176         case ':':
1177             *q++ = pathSep;
1178             break;
1179         default:
1180             *q++ = *p;
1181         }
1182     }
1183     *q = '\0';
1184 
1185     assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
1186     return formatted_path;
1187 }
1188 
1189 // returns a PATH of all entries in the given directory that do not start with a '.'
1190 static char* expand_entries_to_path(char* directory, char fileSep, char pathSep) {
1191   DIR* dir = os::opendir(directory);
1192   if (dir == NULL) return NULL;
1193 
1194   char* path = NULL;
1195   size_t path_len = 0;  // path length including \0 terminator
1196 
1197   size_t directory_len = strlen(directory);
1198   struct dirent *entry;
1199   char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(directory), mtInternal);
1200   while ((entry = os::readdir(dir, (dirent *) dbuf)) != NULL) {
1201     const char* name = entry->d_name;
1202     if (name[0] == '.') continue;
1203 
1204     size_t name_len = strlen(name);
1205     size_t needed = directory_len + name_len + 2;
1206     size_t new_len = path_len + needed;
1207     if (path == NULL) {
1208       path = NEW_C_HEAP_ARRAY(char, new_len, mtInternal);
1209     } else {
1210       path = REALLOC_C_HEAP_ARRAY(char, path, new_len, mtInternal);
1211     }
1212     if (path == NULL)
1213       break;
1214 
1215     // append <pathSep>directory<fileSep>name
1216     char* p = path;
1217     if (path_len > 0) {
1218       p += (path_len -1);
1219       *p = pathSep;
1220       p++;
1221     }
1222 
1223     strcpy(p, directory);
1224     p += directory_len;
1225 
1226     *p = fileSep;
1227     p++;
1228 
1229     strcpy(p, name);
1230     p += name_len;
1231 
1232     path_len = new_len;
1233   }
1234 
1235   FREE_C_HEAP_ARRAY(char, dbuf);
1236   os::closedir(dir);
1237 
1238   return path;
1239 }
1240 
1241 bool os::set_boot_path(char fileSep, char pathSep) {
1242   const char* home = Arguments::get_java_home();
1243   int home_len = (int)strlen(home);
1244 
1245   char* sysclasspath = NULL;
1246   struct stat st;
1247 
1248   // modular image if bootmodules.jimage exists
1249   char* jimage = format_boot_path("%/lib/modules/" BOOT_IMAGE_NAME, home, home_len, fileSep, pathSep);
1250   if (jimage == NULL) return false;
1251   bool has_jimage = (os::stat(jimage, &st) == 0);
1252   if (has_jimage) {
1253     Arguments::set_sysclasspath(jimage);
1254     FREE_C_HEAP_ARRAY(char, jimage);
1255     return true;
1256   }
1257   FREE_C_HEAP_ARRAY(char, jimage);
1258 
1259   // check if developer build with exploded modules
1260   char* modules_dir = format_boot_path("%/modules", home, home_len, fileSep, pathSep);
1261   if (os::stat(modules_dir, &st) == 0) {
1262     if ((st.st_mode & S_IFDIR) == S_IFDIR) {
1263       sysclasspath = expand_entries_to_path(modules_dir, fileSep, pathSep);
1264     }
1265   }
1266   FREE_C_HEAP_ARRAY(char, modules_dir);
1267 
1268   // fallback to classes
1269   if (sysclasspath == NULL)
1270     sysclasspath = format_boot_path("%/classes", home, home_len, fileSep, pathSep);
1271 
1272   if (sysclasspath == NULL) return false;
1273   Arguments::set_sysclasspath(sysclasspath);
1274   FREE_C_HEAP_ARRAY(char, sysclasspath);
1275 
1276   return true;
1277 }
1278 
1279 /*
1280  * Splits a path, based on its separator, the number of
1281  * elements is returned back in n.
1282  * It is the callers responsibility to:
1283  *   a> check the value of n, and n may be 0.
1284  *   b> ignore any empty path elements
1285  *   c> free up the data.
1286  */
1287 char** os::split_path(const char* path, int* n) {
1288   *n = 0;
1289   if (path == NULL || strlen(path) == 0) {
1290     return NULL;
1291   }
1292   const char psepchar = *os::path_separator();
1293   char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal);
1294   if (inpath == NULL) {
1295     return NULL;
1296   }
1297   strcpy(inpath, path);
1298   int count = 1;
1299   char* p = strchr(inpath, psepchar);
1300   // Get a count of elements to allocate memory
1301   while (p != NULL) {
1302     count++;
1303     p++;
1304     p = strchr(p, psepchar);
1305   }
1306   char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count, mtInternal);
1307   if (opath == NULL) {
1308     return NULL;
1309   }
1310 
1311   // do the actual splitting
1312   p = inpath;
1313   for (int i = 0 ; i < count ; i++) {
1314     size_t len = strcspn(p, os::path_separator());
1315     if (len > JVM_MAXPATHLEN) {
1316       return NULL;
1317     }
1318     // allocate the string and add terminator storage
1319     char* s  = (char*)NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
1320     if (s == NULL) {
1321       return NULL;
1322     }
1323     strncpy(s, p, len);
1324     s[len] = '\0';
1325     opath[i] = s;
1326     p += len + 1;
1327   }
1328   FREE_C_HEAP_ARRAY(char, inpath);
1329   *n = count;
1330   return opath;
1331 }
1332 
1333 void os::set_memory_serialize_page(address page) {
1334   int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64);
1335   _mem_serialize_page = (volatile int32_t *)page;
1336   // We initialize the serialization page shift count here
1337   // We assume a cache line size of 64 bytes
1338   assert(SerializePageShiftCount == count,
1339          "thread size changed, fix SerializePageShiftCount constant");
1340   set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t)));
1341 }
1342 
1343 static volatile intptr_t SerializePageLock = 0;
1344 
1345 // This method is called from signal handler when SIGSEGV occurs while the current
1346 // thread tries to store to the "read-only" memory serialize page during state
1347 // transition.
1348 void os::block_on_serialize_page_trap() {
1349   log_debug(safepoint)("Block until the serialize page permission restored");
1350 
1351   // When VMThread is holding the SerializePageLock during modifying the
1352   // access permission of the memory serialize page, the following call
1353   // will block until the permission of that page is restored to rw.
1354   // Generally, it is unsafe to manipulate locks in signal handlers, but in
1355   // this case, it's OK as the signal is synchronous and we know precisely when
1356   // it can occur.
1357   Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page");
1358   Thread::muxRelease(&SerializePageLock);
1359 }
1360 
1361 // Serialize all thread state variables
1362 void os::serialize_thread_states() {
1363   // On some platforms such as Solaris & Linux, the time duration of the page
1364   // permission restoration is observed to be much longer than expected  due to
1365   // scheduler starvation problem etc. To avoid the long synchronization
1366   // time and expensive page trap spinning, 'SerializePageLock' is used to block
1367   // the mutator thread if such case is encountered. See bug 6546278 for details.
1368   Thread::muxAcquire(&SerializePageLock, "serialize_thread_states");
1369   os::protect_memory((char *)os::get_memory_serialize_page(),
1370                      os::vm_page_size(), MEM_PROT_READ);
1371   os::protect_memory((char *)os::get_memory_serialize_page(),
1372                      os::vm_page_size(), MEM_PROT_RW);
1373   Thread::muxRelease(&SerializePageLock);
1374 }
1375 
1376 // Returns true if the current stack pointer is above the stack shadow
1377 // pages, false otherwise.
1378 
1379 bool os::stack_shadow_pages_available(Thread *thread, const methodHandle& method) {
1380   assert(StackRedPages > 0 && StackYellowPages > 0,"Sanity check");
1381   address sp = current_stack_pointer();
1382   // Check if we have StackShadowPages above the yellow zone.  This parameter
1383   // is dependent on the depth of the maximum VM call stack possible from
1384   // the handler for stack overflow.  'instanceof' in the stack overflow
1385   // handler or a println uses at least 8k stack of VM and native code
1386   // respectively.
1387   const int framesize_in_bytes =
1388     Interpreter::size_top_interpreter_activation(method()) * wordSize;
1389   int reserved_area = ((StackShadowPages + StackRedPages + StackYellowPages)
1390                       * vm_page_size()) + framesize_in_bytes;
1391   // The very lower end of the stack
1392   address stack_limit = thread->stack_base() - thread->stack_size();
1393   return (sp > (stack_limit + reserved_area));
1394 }
1395 
1396 size_t os::page_size_for_region(size_t region_size, size_t min_pages, bool must_be_aligned) {
1397   assert(min_pages > 0, "sanity");
1398   if (UseLargePages) {
1399     const size_t max_page_size = region_size / min_pages;
1400 
1401     for (size_t i = 0; _page_sizes[i] != 0; ++i) {
1402       const size_t page_size = _page_sizes[i];
1403       if (page_size <= max_page_size) {
1404         if (!must_be_aligned || is_size_aligned(region_size, page_size)) {
1405           return page_size;
1406         }
1407       }
1408     }
1409   }
1410 
1411   return vm_page_size();
1412 }
1413 
1414 size_t os::page_size_for_region_aligned(size_t region_size, size_t min_pages) {
1415   return page_size_for_region(region_size, min_pages, true);
1416 }
1417 
1418 size_t os::page_size_for_region_unaligned(size_t region_size, size_t min_pages) {
1419   return page_size_for_region(region_size, min_pages, false);
1420 }
1421 
1422 #ifndef PRODUCT
1423 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count)
1424 {
1425   if (TracePageSizes) {
1426     tty->print("%s: ", str);
1427     for (int i = 0; i < count; ++i) {
1428       tty->print(" " SIZE_FORMAT, page_sizes[i]);
1429     }
1430     tty->cr();
1431   }
1432 }
1433 
1434 void os::trace_page_sizes(const char* str, const size_t region_min_size,
1435                           const size_t region_max_size, const size_t page_size,
1436                           const char* base, const size_t size)
1437 {
1438   if (TracePageSizes) {
1439     tty->print_cr("%s:  min=" SIZE_FORMAT " max=" SIZE_FORMAT
1440                   " pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT
1441                   " size=" SIZE_FORMAT,
1442                   str, region_min_size, region_max_size,
1443                   page_size, p2i(base), size);
1444   }
1445 }
1446 #endif  // #ifndef PRODUCT
1447 
1448 // This is the working definition of a server class machine:
1449 // >= 2 physical CPU's and >=2GB of memory, with some fuzz
1450 // because the graphics memory (?) sometimes masks physical memory.
1451 // If you want to change the definition of a server class machine
1452 // on some OS or platform, e.g., >=4GB on Windows platforms,
1453 // then you'll have to parameterize this method based on that state,
1454 // as was done for logical processors here, or replicate and
1455 // specialize this method for each platform.  (Or fix os to have
1456 // some inheritance structure and use subclassing.  Sigh.)
1457 // If you want some platform to always or never behave as a server
1458 // class machine, change the setting of AlwaysActAsServerClassMachine
1459 // and NeverActAsServerClassMachine in globals*.hpp.
1460 bool os::is_server_class_machine() {
1461   // First check for the early returns
1462   if (NeverActAsServerClassMachine) {
1463     return false;
1464   }
1465   if (AlwaysActAsServerClassMachine) {
1466     return true;
1467   }
1468   // Then actually look at the machine
1469   bool         result            = false;
1470   const unsigned int    server_processors = 2;
1471   const julong server_memory     = 2UL * G;
1472   // We seem not to get our full complement of memory.
1473   //     We allow some part (1/8?) of the memory to be "missing",
1474   //     based on the sizes of DIMMs, and maybe graphics cards.
1475   const julong missing_memory   = 256UL * M;
1476 
1477   /* Is this a server class machine? */
1478   if ((os::active_processor_count() >= (int)server_processors) &&
1479       (os::physical_memory() >= (server_memory - missing_memory))) {
1480     const unsigned int logical_processors =
1481       VM_Version::logical_processors_per_package();
1482     if (logical_processors > 1) {
1483       const unsigned int physical_packages =
1484         os::active_processor_count() / logical_processors;
1485       if (physical_packages > server_processors) {
1486         result = true;
1487       }
1488     } else {
1489       result = true;
1490     }
1491   }
1492   return result;
1493 }
1494 
1495 void os::SuspendedThreadTask::run() {
1496   assert(Threads_lock->owned_by_self() || (_thread == VMThread::vm_thread()), "must have threads lock to call this");
1497   internal_do_task();
1498   _done = true;
1499 }
1500 
1501 bool os::create_stack_guard_pages(char* addr, size_t bytes) {
1502   return os::pd_create_stack_guard_pages(addr, bytes);
1503 }
1504 
1505 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint) {
1506   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1507   if (result != NULL) {
1508     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1509   }
1510 
1511   return result;
1512 }
1513 
1514 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint,
1515    MEMFLAGS flags) {
1516   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1517   if (result != NULL) {
1518     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1519     MemTracker::record_virtual_memory_type((address)result, flags);
1520   }
1521 
1522   return result;
1523 }
1524 
1525 char* os::attempt_reserve_memory_at(size_t bytes, char* addr) {
1526   char* result = pd_attempt_reserve_memory_at(bytes, addr);
1527   if (result != NULL) {
1528     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1529   }
1530   return result;
1531 }
1532 
1533 void os::split_reserved_memory(char *base, size_t size,
1534                                  size_t split, bool realloc) {
1535   pd_split_reserved_memory(base, size, split, realloc);
1536 }
1537 
1538 bool os::commit_memory(char* addr, size_t bytes, bool executable) {
1539   bool res = pd_commit_memory(addr, bytes, executable);
1540   if (res) {
1541     MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1542   }
1543   return res;
1544 }
1545 
1546 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
1547                               bool executable) {
1548   bool res = os::pd_commit_memory(addr, size, alignment_hint, executable);
1549   if (res) {
1550     MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1551   }
1552   return res;
1553 }
1554 
1555 void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable,
1556                                const char* mesg) {
1557   pd_commit_memory_or_exit(addr, bytes, executable, mesg);
1558   MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1559 }
1560 
1561 void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint,
1562                                bool executable, const char* mesg) {
1563   os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg);
1564   MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1565 }
1566 
1567 bool os::uncommit_memory(char* addr, size_t bytes) {
1568   bool res;
1569   if (MemTracker::tracking_level() > NMT_minimal) {
1570     Tracker tkr = MemTracker::get_virtual_memory_uncommit_tracker();
1571     res = pd_uncommit_memory(addr, bytes);
1572     if (res) {
1573       tkr.record((address)addr, bytes);
1574     }
1575   } else {
1576     res = pd_uncommit_memory(addr, bytes);
1577   }
1578   return res;
1579 }
1580 
1581 bool os::release_memory(char* addr, size_t bytes) {
1582   bool res;
1583   if (MemTracker::tracking_level() > NMT_minimal) {
1584     Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1585     res = pd_release_memory(addr, bytes);
1586     if (res) {
1587       tkr.record((address)addr, bytes);
1588     }
1589   } else {
1590     res = pd_release_memory(addr, bytes);
1591   }
1592   return res;
1593 }
1594 
1595 void os::pretouch_memory(char* start, char* end) {
1596   for (volatile char *p = start; p < end; p += os::vm_page_size()) {
1597     *p = 0;
1598   }
1599 }
1600 
1601 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
1602                            char *addr, size_t bytes, bool read_only,
1603                            bool allow_exec) {
1604   char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec);
1605   if (result != NULL) {
1606     MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1607   }
1608   return result;
1609 }
1610 
1611 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
1612                              char *addr, size_t bytes, bool read_only,
1613                              bool allow_exec) {
1614   return pd_remap_memory(fd, file_name, file_offset, addr, bytes,
1615                     read_only, allow_exec);
1616 }
1617 
1618 bool os::unmap_memory(char *addr, size_t bytes) {
1619   bool result;
1620   if (MemTracker::tracking_level() > NMT_minimal) {
1621     Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1622     result = pd_unmap_memory(addr, bytes);
1623     if (result) {
1624       tkr.record((address)addr, bytes);
1625     }
1626   } else {
1627     result = pd_unmap_memory(addr, bytes);
1628   }
1629   return result;
1630 }
1631 
1632 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
1633   pd_free_memory(addr, bytes, alignment_hint);
1634 }
1635 
1636 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
1637   pd_realign_memory(addr, bytes, alignment_hint);
1638 }
1639 
1640 #ifndef TARGET_OS_FAMILY_windows
1641 /* try to switch state from state "from" to state "to"
1642  * returns the state set after the method is complete
1643  */
1644 os::SuspendResume::State os::SuspendResume::switch_state(os::SuspendResume::State from,
1645                                                          os::SuspendResume::State to)
1646 {
1647   os::SuspendResume::State result =
1648     (os::SuspendResume::State) Atomic::cmpxchg((jint) to, (jint *) &_state, (jint) from);
1649   if (result == from) {
1650     // success
1651     return to;
1652   }
1653   return result;
1654 }
1655 #endif
1656 
1657 /////////////// Unit tests ///////////////
1658 
1659 #ifndef PRODUCT
1660 
1661 #define assert_eq(a,b) assert(a == b, SIZE_FORMAT " != " SIZE_FORMAT, a, b)
1662 
1663 class TestOS : AllStatic {
1664   static size_t small_page_size() {
1665     return os::vm_page_size();
1666   }
1667 
1668   static size_t large_page_size() {
1669     const size_t large_page_size_example = 4 * M;
1670     return os::page_size_for_region_aligned(large_page_size_example, 1);
1671   }
1672 
1673   static void test_page_size_for_region_aligned() {
1674     if (UseLargePages) {
1675       const size_t small_page = small_page_size();
1676       const size_t large_page = large_page_size();
1677 
1678       if (large_page > small_page) {
1679         size_t num_small_pages_in_large = large_page / small_page;
1680         size_t page = os::page_size_for_region_aligned(large_page, num_small_pages_in_large);
1681 
1682         assert_eq(page, small_page);
1683       }
1684     }
1685   }
1686 
1687   static void test_page_size_for_region_alignment() {
1688     if (UseLargePages) {
1689       const size_t small_page = small_page_size();
1690       const size_t large_page = large_page_size();
1691       if (large_page > small_page) {
1692         const size_t unaligned_region = large_page + 17;
1693         size_t page = os::page_size_for_region_aligned(unaligned_region, 1);
1694         assert_eq(page, small_page);
1695 
1696         const size_t num_pages = 5;
1697         const size_t aligned_region = large_page * num_pages;
1698         page = os::page_size_for_region_aligned(aligned_region, num_pages);
1699         assert_eq(page, large_page);
1700       }
1701     }
1702   }
1703 
1704   static void test_page_size_for_region_unaligned() {
1705     if (UseLargePages) {
1706       // Given exact page size, should return that page size.
1707       for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
1708         size_t expected = os::_page_sizes[i];
1709         size_t actual = os::page_size_for_region_unaligned(expected, 1);
1710         assert_eq(expected, actual);
1711       }
1712 
1713       // Given slightly larger size than a page size, return the page size.
1714       for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
1715         size_t expected = os::_page_sizes[i];
1716         size_t actual = os::page_size_for_region_unaligned(expected + 17, 1);
1717         assert_eq(expected, actual);
1718       }
1719 
1720       // Given a slightly smaller size than a page size,
1721       // return the next smaller page size.
1722       if (os::_page_sizes[1] > os::_page_sizes[0]) {
1723         size_t expected = os::_page_sizes[0];
1724         size_t actual = os::page_size_for_region_unaligned(os::_page_sizes[1] - 17, 1);
1725         assert_eq(actual, expected);
1726       }
1727 
1728       // Return small page size for values less than a small page.
1729       size_t small_page = small_page_size();
1730       size_t actual = os::page_size_for_region_unaligned(small_page - 17, 1);
1731       assert_eq(small_page, actual);
1732     }
1733   }
1734 
1735  public:
1736   static void run_tests() {
1737     test_page_size_for_region_aligned();
1738     test_page_size_for_region_alignment();
1739     test_page_size_for_region_unaligned();
1740   }
1741 };
1742 
1743 void TestOS_test() {
1744   TestOS::run_tests();
1745 }
1746 
1747 #endif // PRODUCT