1 /*
   2  * Copyright (c) 1997, 2016, 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::jdk_internal_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   // We need to adapt the configured number of stack protection pages given
 320   // in 4K pages to the actual os page size. We must do this before setting
 321   // up minimal stack sizes etc. in os::init_2().
 322   JavaThread::set_stack_red_zone_size     (align_size_up(StackRedPages      * 4 * K, vm_page_size()));
 323   JavaThread::set_stack_yellow_zone_size  (align_size_up(StackYellowPages   * 4 * K, vm_page_size()));
 324   JavaThread::set_stack_reserved_zone_size(align_size_up(StackReservedPages * 4 * K, vm_page_size()));
 325   JavaThread::set_stack_shadow_zone_size  (align_size_up(StackShadowPages   * 4 * K, vm_page_size()));
 326 
 327   // VM version initialization identifies some characteristics of the
 328   // platform that are used during ergonomic decisions.
 329   VM_Version::init_before_ergo();
 330 }
 331 
 332 void os::signal_init() {
 333   if (!ReduceSignalUsage) {
 334     // Setup JavaThread for processing signals
 335     EXCEPTION_MARK;
 336     Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
 337     instanceKlassHandle klass (THREAD, k);
 338     instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
 339 
 340     const char thread_name[] = "Signal Dispatcher";
 341     Handle string = java_lang_String::create_from_str(thread_name, CHECK);
 342 
 343     // Initialize thread_oop to put it into the system threadGroup
 344     Handle thread_group (THREAD, Universe::system_thread_group());
 345     JavaValue result(T_VOID);
 346     JavaCalls::call_special(&result, thread_oop,
 347                            klass,
 348                            vmSymbols::object_initializer_name(),
 349                            vmSymbols::threadgroup_string_void_signature(),
 350                            thread_group,
 351                            string,
 352                            CHECK);
 353 
 354     KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
 355     JavaCalls::call_special(&result,
 356                             thread_group,
 357                             group,
 358                             vmSymbols::add_method_name(),
 359                             vmSymbols::thread_void_signature(),
 360                             thread_oop,         // ARG 1
 361                             CHECK);
 362 
 363     os::signal_init_pd();
 364 
 365     { MutexLocker mu(Threads_lock);
 366       JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
 367 
 368       // At this point it may be possible that no osthread was created for the
 369       // JavaThread due to lack of memory. We would have to throw an exception
 370       // in that case. However, since this must work and we do not allow
 371       // exceptions anyway, check and abort if this fails.
 372       if (signal_thread == NULL || signal_thread->osthread() == NULL) {
 373         vm_exit_during_initialization("java.lang.OutOfMemoryError",
 374                                       os::native_thread_creation_failed_msg());
 375       }
 376 
 377       java_lang_Thread::set_thread(thread_oop(), signal_thread);
 378       java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
 379       java_lang_Thread::set_daemon(thread_oop());
 380 
 381       signal_thread->set_threadObj(thread_oop());
 382       Threads::add(signal_thread);
 383       Thread::start(signal_thread);
 384     }
 385     // Handle ^BREAK
 386     os::signal(SIGBREAK, os::user_handler());
 387   }
 388 }
 389 
 390 
 391 void os::terminate_signal_thread() {
 392   if (!ReduceSignalUsage)
 393     signal_notify(sigexitnum_pd());
 394 }
 395 
 396 
 397 // --------------------- loading libraries ---------------------
 398 
 399 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
 400 extern struct JavaVM_ main_vm;
 401 
 402 static void* _native_java_library = NULL;
 403 
 404 void* os::native_java_library() {
 405   if (_native_java_library == NULL) {
 406     char buffer[JVM_MAXPATHLEN];
 407     char ebuf[1024];
 408 
 409     // Try to load verify dll first. In 1.3 java dll depends on it and is not
 410     // always able to find it when the loading executable is outside the JDK.
 411     // In order to keep working with 1.2 we ignore any loading errors.
 412     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 413                        "verify")) {
 414       dll_load(buffer, ebuf, sizeof(ebuf));
 415     }
 416 
 417     // Load java dll
 418     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 419                        "java")) {
 420       _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
 421     }
 422     if (_native_java_library == NULL) {
 423       vm_exit_during_initialization("Unable to load native library", ebuf);
 424     }
 425 
 426 #if defined(__OpenBSD__)
 427     // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so
 428     // ignore errors
 429     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 430                        "net")) {
 431       dll_load(buffer, ebuf, sizeof(ebuf));
 432     }
 433 #endif
 434   }
 435   return _native_java_library;
 436 }
 437 
 438 /*
 439  * Support for finding Agent_On(Un)Load/Attach<_lib_name> if it exists.
 440  * If check_lib == true then we are looking for an
 441  * Agent_OnLoad_lib_name or Agent_OnAttach_lib_name function to determine if
 442  * this library is statically linked into the image.
 443  * If check_lib == false then we will look for the appropriate symbol in the
 444  * executable if agent_lib->is_static_lib() == true or in the shared library
 445  * referenced by 'handle'.
 446  */
 447 void* os::find_agent_function(AgentLibrary *agent_lib, bool check_lib,
 448                               const char *syms[], size_t syms_len) {
 449   assert(agent_lib != NULL, "sanity check");
 450   const char *lib_name;
 451   void *handle = agent_lib->os_lib();
 452   void *entryName = NULL;
 453   char *agent_function_name;
 454   size_t i;
 455 
 456   // If checking then use the agent name otherwise test is_static_lib() to
 457   // see how to process this lookup
 458   lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : NULL);
 459   for (i = 0; i < syms_len; i++) {
 460     agent_function_name = build_agent_function_name(syms[i], lib_name, agent_lib->is_absolute_path());
 461     if (agent_function_name == NULL) {
 462       break;
 463     }
 464     entryName = dll_lookup(handle, agent_function_name);
 465     FREE_C_HEAP_ARRAY(char, agent_function_name);
 466     if (entryName != NULL) {
 467       break;
 468     }
 469   }
 470   return entryName;
 471 }
 472 
 473 // See if the passed in agent is statically linked into the VM image.
 474 bool os::find_builtin_agent(AgentLibrary *agent_lib, const char *syms[],
 475                             size_t syms_len) {
 476   void *ret;
 477   void *proc_handle;
 478   void *save_handle;
 479 
 480   assert(agent_lib != NULL, "sanity check");
 481   if (agent_lib->name() == NULL) {
 482     return false;
 483   }
 484   proc_handle = get_default_process_handle();
 485   // Check for Agent_OnLoad/Attach_lib_name function
 486   save_handle = agent_lib->os_lib();
 487   // We want to look in this process' symbol table.
 488   agent_lib->set_os_lib(proc_handle);
 489   ret = find_agent_function(agent_lib, true, syms, syms_len);
 490   if (ret != NULL) {
 491     // Found an entry point like Agent_OnLoad_lib_name so we have a static agent
 492     agent_lib->set_valid();
 493     agent_lib->set_static_lib(true);
 494     return true;
 495   }
 496   agent_lib->set_os_lib(save_handle);
 497   return false;
 498 }
 499 
 500 // --------------------- heap allocation utilities ---------------------
 501 
 502 char *os::strdup(const char *str, MEMFLAGS flags) {
 503   size_t size = strlen(str);
 504   char *dup_str = (char *)malloc(size + 1, flags);
 505   if (dup_str == NULL) return NULL;
 506   strcpy(dup_str, str);
 507   return dup_str;
 508 }
 509 
 510 char* os::strdup_check_oom(const char* str, MEMFLAGS flags) {
 511   char* p = os::strdup(str, flags);
 512   if (p == NULL) {
 513     vm_exit_out_of_memory(strlen(str) + 1, OOM_MALLOC_ERROR, "os::strdup_check_oom");
 514   }
 515   return p;
 516 }
 517 
 518 
 519 #define paranoid                 0  /* only set to 1 if you suspect checking code has bug */
 520 
 521 #ifdef ASSERT
 522 
 523 static void verify_memory(void* ptr) {
 524   GuardedMemory guarded(ptr);
 525   if (!guarded.verify_guards()) {
 526     tty->print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees);
 527     tty->print_cr("## memory stomp:");
 528     guarded.print_on(tty);
 529     fatal("memory stomping error");
 530   }
 531 }
 532 
 533 #endif
 534 
 535 //
 536 // This function supports testing of the malloc out of memory
 537 // condition without really running the system out of memory.
 538 //
 539 static bool has_reached_max_malloc_test_peak(size_t alloc_size) {
 540   if (MallocMaxTestWords > 0) {
 541     jint words = (jint)(alloc_size / BytesPerWord);
 542 
 543     if ((cur_malloc_words + words) > MallocMaxTestWords) {
 544       return true;
 545     }
 546     Atomic::add(words, (volatile jint *)&cur_malloc_words);
 547   }
 548   return false;
 549 }
 550 
 551 void* os::malloc(size_t size, MEMFLAGS flags) {
 552   return os::malloc(size, flags, CALLER_PC);
 553 }
 554 
 555 void* os::malloc(size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
 556   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 557   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 558 
 559 #ifdef ASSERT
 560   // checking for the WatcherThread and crash_protection first
 561   // since os::malloc can be called when the libjvm.{dll,so} is
 562   // first loaded and we don't have a thread yet.
 563   // try to find the thread after we see that the watcher thread
 564   // exists and has crash protection.
 565   WatcherThread *wt = WatcherThread::watcher_thread();
 566   if (wt != NULL && wt->has_crash_protection()) {
 567     Thread* thread = Thread::current_or_null();
 568     if (thread == wt) {
 569       assert(!wt->has_crash_protection(),
 570           "Can't malloc with crash protection from WatcherThread");
 571     }
 572   }
 573 #endif
 574 
 575   if (size == 0) {
 576     // return a valid pointer if size is zero
 577     // if NULL is returned the calling functions assume out of memory.
 578     size = 1;
 579   }
 580 
 581   // NMT support
 582   NMT_TrackingLevel level = MemTracker::tracking_level();
 583   size_t            nmt_header_size = MemTracker::malloc_header_size(level);
 584 
 585 #ifndef ASSERT
 586   const size_t alloc_size = size + nmt_header_size;
 587 #else
 588   const size_t alloc_size = GuardedMemory::get_total_size(size + nmt_header_size);
 589   if (size + nmt_header_size > alloc_size) { // Check for rollover.
 590     return NULL;
 591   }
 592 #endif
 593 
 594   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 595 
 596   // For the test flag -XX:MallocMaxTestWords
 597   if (has_reached_max_malloc_test_peak(size)) {
 598     return NULL;
 599   }
 600 
 601   u_char* ptr;
 602   ptr = (u_char*)::malloc(alloc_size);
 603 
 604 #ifdef ASSERT
 605   if (ptr == NULL) {
 606     return NULL;
 607   }
 608   // Wrap memory with guard
 609   GuardedMemory guarded(ptr, size + nmt_header_size);
 610   ptr = guarded.get_user_ptr();
 611 #endif
 612   if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
 613     tty->print_cr("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
 614     breakpoint();
 615   }
 616   debug_only(if (paranoid) verify_memory(ptr));
 617   if (PrintMalloc && tty != NULL) {
 618     tty->print_cr("os::malloc " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
 619   }
 620 
 621   // we do not track guard memory
 622   return MemTracker::record_malloc((address)ptr, size, memflags, stack, level);
 623 }
 624 
 625 void* os::realloc(void *memblock, size_t size, MEMFLAGS flags) {
 626   return os::realloc(memblock, size, flags, CALLER_PC);
 627 }
 628 
 629 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
 630 
 631   // For the test flag -XX:MallocMaxTestWords
 632   if (has_reached_max_malloc_test_peak(size)) {
 633     return NULL;
 634   }
 635 
 636 #ifndef ASSERT
 637   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 638   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 639    // NMT support
 640   void* membase = MemTracker::record_free(memblock);
 641   NMT_TrackingLevel level = MemTracker::tracking_level();
 642   size_t  nmt_header_size = MemTracker::malloc_header_size(level);
 643   void* ptr = ::realloc(membase, size + nmt_header_size);
 644   return MemTracker::record_malloc(ptr, size, memflags, stack, level);
 645 #else
 646   if (memblock == NULL) {
 647     return os::malloc(size, memflags, stack);
 648   }
 649   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 650     tty->print_cr("os::realloc caught " PTR_FORMAT, p2i(memblock));
 651     breakpoint();
 652   }
 653   // NMT support
 654   void* membase = MemTracker::malloc_base(memblock);
 655   verify_memory(membase);
 656   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 657   if (size == 0) {
 658     return NULL;
 659   }
 660   // always move the block
 661   void* ptr = os::malloc(size, memflags, stack);
 662   if (PrintMalloc && tty != NULL) {
 663     tty->print_cr("os::realloc " SIZE_FORMAT " bytes, " PTR_FORMAT " --> " PTR_FORMAT, size, p2i(memblock), p2i(ptr));
 664   }
 665   // Copy to new memory if malloc didn't fail
 666   if ( ptr != NULL ) {
 667     GuardedMemory guarded(MemTracker::malloc_base(memblock));
 668     // Guard's user data contains NMT header
 669     size_t memblock_size = guarded.get_user_size() - MemTracker::malloc_header_size(memblock);
 670     memcpy(ptr, memblock, MIN2(size, memblock_size));
 671     if (paranoid) verify_memory(MemTracker::malloc_base(ptr));
 672     if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
 673       tty->print_cr("os::realloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
 674       breakpoint();
 675     }
 676     os::free(memblock);
 677   }
 678   return ptr;
 679 #endif
 680 }
 681 
 682 
 683 void  os::free(void *memblock) {
 684   NOT_PRODUCT(inc_stat_counter(&num_frees, 1));
 685 #ifdef ASSERT
 686   if (memblock == NULL) return;
 687   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 688     if (tty != NULL) tty->print_cr("os::free caught " PTR_FORMAT, p2i(memblock));
 689     breakpoint();
 690   }
 691   void* membase = MemTracker::record_free(memblock);
 692   verify_memory(membase);
 693   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 694 
 695   GuardedMemory guarded(membase);
 696   size_t size = guarded.get_user_size();
 697   inc_stat_counter(&free_bytes, size);
 698   membase = guarded.release_for_freeing();
 699   if (PrintMalloc && tty != NULL) {
 700       fprintf(stderr, "os::free " SIZE_FORMAT " bytes --> " PTR_FORMAT "\n", size, (uintptr_t)membase);
 701   }
 702   ::free(membase);
 703 #else
 704   void* membase = MemTracker::record_free(memblock);
 705   ::free(membase);
 706 #endif
 707 }
 708 
 709 void os::init_random(long initval) {
 710   _rand_seed = initval;
 711 }
 712 
 713 
 714 long os::random() {
 715   /* standard, well-known linear congruential random generator with
 716    * next_rand = (16807*seed) mod (2**31-1)
 717    * see
 718    * (1) "Random Number Generators: Good Ones Are Hard to Find",
 719    *      S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
 720    * (2) "Two Fast Implementations of the 'Minimal Standard' Random
 721    *     Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
 722   */
 723   const long a = 16807;
 724   const unsigned long m = 2147483647;
 725   const long q = m / a;        assert(q == 127773, "weird math");
 726   const long r = m % a;        assert(r == 2836, "weird math");
 727 
 728   // compute az=2^31p+q
 729   unsigned long lo = a * (long)(_rand_seed & 0xFFFF);
 730   unsigned long hi = a * (long)((unsigned long)_rand_seed >> 16);
 731   lo += (hi & 0x7FFF) << 16;
 732 
 733   // if q overflowed, ignore the overflow and increment q
 734   if (lo > m) {
 735     lo &= m;
 736     ++lo;
 737   }
 738   lo += hi >> 15;
 739 
 740   // if (p+q) overflowed, ignore the overflow and increment (p+q)
 741   if (lo > m) {
 742     lo &= m;
 743     ++lo;
 744   }
 745   return (_rand_seed = lo);
 746 }
 747 
 748 // The INITIALIZED state is distinguished from the SUSPENDED state because the
 749 // conditions in which a thread is first started are different from those in which
 750 // a suspension is resumed.  These differences make it hard for us to apply the
 751 // tougher checks when starting threads that we want to do when resuming them.
 752 // However, when start_thread is called as a result of Thread.start, on a Java
 753 // thread, the operation is synchronized on the Java Thread object.  So there
 754 // cannot be a race to start the thread and hence for the thread to exit while
 755 // we are working on it.  Non-Java threads that start Java threads either have
 756 // to do so in a context in which races are impossible, or should do appropriate
 757 // locking.
 758 
 759 void os::start_thread(Thread* thread) {
 760   // guard suspend/resume
 761   MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
 762   OSThread* osthread = thread->osthread();
 763   osthread->set_state(RUNNABLE);
 764   pd_start_thread(thread);
 765 }
 766 
 767 void os::abort(bool dump_core) {
 768   abort(dump_core && CreateCoredumpOnCrash, NULL, NULL);
 769 }
 770 
 771 //---------------------------------------------------------------------------
 772 // Helper functions for fatal error handler
 773 
 774 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
 775   assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
 776 
 777   int cols = 0;
 778   int cols_per_line = 0;
 779   switch (unitsize) {
 780     case 1: cols_per_line = 16; break;
 781     case 2: cols_per_line = 8;  break;
 782     case 4: cols_per_line = 4;  break;
 783     case 8: cols_per_line = 2;  break;
 784     default: return;
 785   }
 786 
 787   address p = start;
 788   st->print(PTR_FORMAT ":   ", p2i(start));
 789   while (p < end) {
 790     switch (unitsize) {
 791       case 1: st->print("%02x", *(u1*)p); break;
 792       case 2: st->print("%04x", *(u2*)p); break;
 793       case 4: st->print("%08x", *(u4*)p); break;
 794       case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
 795     }
 796     p += unitsize;
 797     cols++;
 798     if (cols >= cols_per_line && p < end) {
 799        cols = 0;
 800        st->cr();
 801        st->print(PTR_FORMAT ":   ", p2i(p));
 802     } else {
 803        st->print(" ");
 804     }
 805   }
 806   st->cr();
 807 }
 808 
 809 void os::print_environment_variables(outputStream* st, const char** env_list) {
 810   if (env_list) {
 811     st->print_cr("Environment Variables:");
 812 
 813     for (int i = 0; env_list[i] != NULL; i++) {
 814       char *envvar = ::getenv(env_list[i]);
 815       if (envvar != NULL) {
 816         st->print("%s", env_list[i]);
 817         st->print("=");
 818         st->print_cr("%s", envvar);
 819       }
 820     }
 821   }
 822 }
 823 
 824 void os::print_cpu_info(outputStream* st, char* buf, size_t buflen) {
 825   // cpu
 826   st->print("CPU:");
 827   st->print("total %d", os::processor_count());
 828   // It's not safe to query number of active processors after crash
 829   // st->print("(active %d)", os::active_processor_count());
 830   st->print(" %s", VM_Version::features_string());
 831   st->cr();
 832   pd_print_cpu_info(st, buf, buflen);
 833 }
 834 
 835 // Print a one line string summarizing the cpu, number of cores, memory, and operating system version
 836 void os::print_summary_info(outputStream* st, char* buf, size_t buflen) {
 837   st->print("Host: ");
 838 #ifndef PRODUCT
 839   if (get_host_name(buf, buflen)) {
 840     st->print("%s, ", buf);
 841   }
 842 #endif // PRODUCT
 843   get_summary_cpu_info(buf, buflen);
 844   st->print("%s, ", buf);
 845   size_t mem = physical_memory()/G;
 846   if (mem == 0) {  // for low memory systems
 847     mem = physical_memory()/M;
 848     st->print("%d cores, " SIZE_FORMAT "M, ", processor_count(), mem);
 849   } else {
 850     st->print("%d cores, " SIZE_FORMAT "G, ", processor_count(), mem);
 851   }
 852   get_summary_os_info(buf, buflen);
 853   st->print_raw(buf);
 854   st->cr();
 855 }
 856 
 857 void os::print_date_and_time(outputStream *st, char* buf, size_t buflen) {
 858   const int secs_per_day  = 86400;
 859   const int secs_per_hour = 3600;
 860   const int secs_per_min  = 60;
 861 
 862   time_t tloc;
 863   (void)time(&tloc);
 864   char* timestring = ctime(&tloc);  // ctime adds newline.
 865   // edit out the newline
 866   char* nl = strchr(timestring, '\n');
 867   if (nl != NULL) {
 868     *nl = '\0';
 869   }
 870 
 871   struct tm tz;
 872   if (localtime_pd(&tloc, &tz) != NULL) {
 873     ::strftime(buf, buflen, "%Z", &tz);
 874     st->print("Time: %s %s", timestring, buf);
 875   } else {
 876     st->print("Time: %s", timestring);
 877   }
 878 
 879   double t = os::elapsedTime();
 880   // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
 881   //       Linux. Must be a bug in glibc ? Workaround is to round "t" to int
 882   //       before printf. We lost some precision, but who cares?
 883   int eltime = (int)t;  // elapsed time in seconds
 884 
 885   // print elapsed time in a human-readable format:
 886   int eldays = eltime / secs_per_day;
 887   int day_secs = eldays * secs_per_day;
 888   int elhours = (eltime - day_secs) / secs_per_hour;
 889   int hour_secs = elhours * secs_per_hour;
 890   int elmins = (eltime - day_secs - hour_secs) / secs_per_min;
 891   int minute_secs = elmins * secs_per_min;
 892   int elsecs = (eltime - day_secs - hour_secs - minute_secs);
 893   st->print_cr(" elapsed time: %d seconds (%dd %dh %dm %ds)", eltime, eldays, elhours, elmins, elsecs);
 894 }
 895 
 896 // moved from debug.cpp (used to be find()) but still called from there
 897 // The verbose parameter is only set by the debug code in one case
 898 void os::print_location(outputStream* st, intptr_t x, bool verbose) {
 899   address addr = (address)x;
 900   CodeBlob* b = CodeCache::find_blob_unsafe(addr);
 901   if (b != NULL) {
 902     if (b->is_buffer_blob()) {
 903       // the interpreter is generated into a buffer blob
 904       InterpreterCodelet* i = Interpreter::codelet_containing(addr);
 905       if (i != NULL) {
 906         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an Interpreter codelet", p2i(addr), (int)(addr - i->code_begin()));
 907         i->print_on(st);
 908         return;
 909       }
 910       if (Interpreter::contains(addr)) {
 911         st->print_cr(INTPTR_FORMAT " is pointing into interpreter code"
 912                      " (not bytecode specific)", p2i(addr));
 913         return;
 914       }
 915       //
 916       if (AdapterHandlerLibrary::contains(b)) {
 917         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an AdapterHandler", p2i(addr), (int)(addr - b->code_begin()));
 918         AdapterHandlerLibrary::print_handler_on(st, b);
 919       }
 920       // the stubroutines are generated into a buffer blob
 921       StubCodeDesc* d = StubCodeDesc::desc_for(addr);
 922       if (d != NULL) {
 923         st->print_cr(INTPTR_FORMAT " is at begin+%d in a stub", p2i(addr), (int)(addr - d->begin()));
 924         d->print_on(st);
 925         st->cr();
 926         return;
 927       }
 928       if (StubRoutines::contains(addr)) {
 929         st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) stub routine", p2i(addr));
 930         return;
 931       }
 932       // the InlineCacheBuffer is using stubs generated into a buffer blob
 933       if (InlineCacheBuffer::contains(addr)) {
 934         st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", p2i(addr));
 935         return;
 936       }
 937       VtableStub* v = VtableStubs::stub_containing(addr);
 938       if (v != NULL) {
 939         st->print_cr(INTPTR_FORMAT " is at entry_point+%d in a vtable stub", p2i(addr), (int)(addr - v->entry_point()));
 940         v->print_on(st);
 941         st->cr();
 942         return;
 943       }
 944     }
 945     nmethod* nm = b->as_nmethod_or_null();
 946     if (nm != NULL) {
 947       ResourceMark rm;
 948       st->print(INTPTR_FORMAT " is at entry_point+%d in (nmethod*)" INTPTR_FORMAT,
 949                 p2i(addr), (int)(addr - nm->entry_point()), p2i(nm));
 950       if (verbose) {
 951         st->print(" for ");
 952         nm->method()->print_value_on(st);
 953       }
 954       st->cr();
 955       nm->print_nmethod(verbose);
 956       return;
 957     }
 958     st->print_cr(INTPTR_FORMAT " is at code_begin+%d in ", p2i(addr), (int)(addr - b->code_begin()));
 959     b->print_on(st);
 960     return;
 961   }
 962 
 963   if (Universe::heap()->is_in(addr)) {
 964     HeapWord* p = Universe::heap()->block_start(addr);
 965     bool print = false;
 966     // If we couldn't find it it just may mean that heap wasn't parsable
 967     // See if we were just given an oop directly
 968     if (p != NULL && Universe::heap()->block_is_obj(p)) {
 969       print = true;
 970     } else if (p == NULL && ((oopDesc*)addr)->is_oop()) {
 971       p = (HeapWord*) addr;
 972       print = true;
 973     }
 974     if (print) {
 975       if (p == (HeapWord*) addr) {
 976         st->print_cr(INTPTR_FORMAT " is an oop", p2i(addr));
 977       } else {
 978         st->print_cr(INTPTR_FORMAT " is pointing into object: " INTPTR_FORMAT, p2i(addr), p2i(p));
 979       }
 980       oop(p)->print_on(st);
 981       return;
 982     }
 983   } else {
 984     if (Universe::heap()->is_in_reserved(addr)) {
 985       st->print_cr(INTPTR_FORMAT " is an unallocated location "
 986                    "in the heap", p2i(addr));
 987       return;
 988     }
 989   }
 990   if (JNIHandles::is_global_handle((jobject) addr)) {
 991     st->print_cr(INTPTR_FORMAT " is a global jni handle", p2i(addr));
 992     return;
 993   }
 994   if (JNIHandles::is_weak_global_handle((jobject) addr)) {
 995     st->print_cr(INTPTR_FORMAT " is a weak global jni handle", p2i(addr));
 996     return;
 997   }
 998 #ifndef PRODUCT
 999   // we don't keep the block list in product mode
1000   if (JNIHandleBlock::any_contains((jobject) addr)) {
1001     st->print_cr(INTPTR_FORMAT " is a local jni handle", p2i(addr));
1002     return;
1003   }
1004 #endif
1005 
1006   for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
1007     // Check for privilege stack
1008     if (thread->privileged_stack_top() != NULL &&
1009         thread->privileged_stack_top()->contains(addr)) {
1010       st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack "
1011                    "for thread: " INTPTR_FORMAT, p2i(addr), p2i(thread));
1012       if (verbose) thread->print_on(st);
1013       return;
1014     }
1015     // If the addr is a java thread print information about that.
1016     if (addr == (address)thread) {
1017       if (verbose) {
1018         thread->print_on(st);
1019       } else {
1020         st->print_cr(INTPTR_FORMAT " is a thread", p2i(addr));
1021       }
1022       return;
1023     }
1024     // If the addr is in the stack region for this thread then report that
1025     // and print thread info
1026     if (thread->on_local_stack(addr)) {
1027       st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
1028                    INTPTR_FORMAT, p2i(addr), p2i(thread));
1029       if (verbose) thread->print_on(st);
1030       return;
1031     }
1032 
1033   }
1034 
1035   // Check if in metaspace and print types that have vptrs (only method now)
1036   if (Metaspace::contains(addr)) {
1037     if (Method::has_method_vptr((const void*)addr)) {
1038       ((Method*)addr)->print_value_on(st);
1039       st->cr();
1040     } else {
1041       // Use addr->print() from the debugger instead (not here)
1042       st->print_cr(INTPTR_FORMAT " is pointing into metadata", p2i(addr));
1043     }
1044     return;
1045   }
1046 
1047   // Try an OS specific find
1048   if (os::find(addr, st)) {
1049     return;
1050   }
1051 
1052   st->print_cr(INTPTR_FORMAT " is an unknown value", p2i(addr));
1053 }
1054 
1055 // Looks like all platforms except IA64 can use the same function to check
1056 // if C stack is walkable beyond current frame. The check for fp() is not
1057 // necessary on Sparc, but it's harmless.
1058 bool os::is_first_C_frame(frame* fr) {
1059 #if (defined(IA64) && !defined(AIX)) && !defined(_WIN32)
1060   // On IA64 we have to check if the callers bsp is still valid
1061   // (i.e. within the register stack bounds).
1062   // Notice: this only works for threads created by the VM and only if
1063   // we walk the current stack!!! If we want to be able to walk
1064   // arbitrary other threads, we'll have to somehow store the thread
1065   // object in the frame.
1066   Thread *thread = Thread::current();
1067   if ((address)fr->fp() <=
1068       thread->register_stack_base() HPUX_ONLY(+ 0x0) LINUX_ONLY(+ 0x50)) {
1069     // This check is a little hacky, because on Linux the first C
1070     // frame's ('start_thread') register stack frame starts at
1071     // "register_stack_base + 0x48" while on HPUX, the first C frame's
1072     // ('__pthread_bound_body') register stack frame seems to really
1073     // start at "register_stack_base".
1074     return true;
1075   } else {
1076     return false;
1077   }
1078 #elif defined(IA64) && defined(_WIN32)
1079   return true;
1080 #else
1081   // Load up sp, fp, sender sp and sender fp, check for reasonable values.
1082   // Check usp first, because if that's bad the other accessors may fault
1083   // on some architectures.  Ditto ufp second, etc.
1084   uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
1085   // sp on amd can be 32 bit aligned.
1086   uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
1087 
1088   uintptr_t usp    = (uintptr_t)fr->sp();
1089   if ((usp & sp_align_mask) != 0) return true;
1090 
1091   uintptr_t ufp    = (uintptr_t)fr->fp();
1092   if ((ufp & fp_align_mask) != 0) return true;
1093 
1094   uintptr_t old_sp = (uintptr_t)fr->sender_sp();
1095   if ((old_sp & sp_align_mask) != 0) return true;
1096   if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
1097 
1098   uintptr_t old_fp = (uintptr_t)fr->link();
1099   if ((old_fp & fp_align_mask) != 0) return true;
1100   if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
1101 
1102   // stack grows downwards; if old_fp is below current fp or if the stack
1103   // frame is too large, either the stack is corrupted or fp is not saved
1104   // on stack (i.e. on x86, ebp may be used as general register). The stack
1105   // is not walkable beyond current frame.
1106   if (old_fp < ufp) return true;
1107   if (old_fp - ufp > 64 * K) return true;
1108 
1109   return false;
1110 #endif
1111 }
1112 
1113 #ifdef ASSERT
1114 extern "C" void test_random() {
1115   const double m = 2147483647;
1116   double mean = 0.0, variance = 0.0, t;
1117   long reps = 10000;
1118   unsigned long seed = 1;
1119 
1120   tty->print_cr("seed %ld for %ld repeats...", seed, reps);
1121   os::init_random(seed);
1122   long num;
1123   for (int k = 0; k < reps; k++) {
1124     num = os::random();
1125     double u = (double)num / m;
1126     assert(u >= 0.0 && u <= 1.0, "bad random number!");
1127 
1128     // calculate mean and variance of the random sequence
1129     mean += u;
1130     variance += (u*u);
1131   }
1132   mean /= reps;
1133   variance /= (reps - 1);
1134 
1135   assert(num == 1043618065, "bad seed");
1136   tty->print_cr("mean of the 1st 10000 numbers: %f", mean);
1137   tty->print_cr("variance of the 1st 10000 numbers: %f", variance);
1138   const double eps = 0.0001;
1139   t = fabsd(mean - 0.5018);
1140   assert(t < eps, "bad mean");
1141   t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355;
1142   assert(t < eps, "bad variance");
1143 }
1144 #endif
1145 
1146 
1147 // Set up the boot classpath.
1148 
1149 char* os::format_boot_path(const char* format_string,
1150                            const char* home,
1151                            int home_len,
1152                            char fileSep,
1153                            char pathSep) {
1154     assert((fileSep == '/' && pathSep == ':') ||
1155            (fileSep == '\\' && pathSep == ';'), "unexpected separator chars");
1156 
1157     // Scan the format string to determine the length of the actual
1158     // boot classpath, and handle platform dependencies as well.
1159     int formatted_path_len = 0;
1160     const char* p;
1161     for (p = format_string; *p != 0; ++p) {
1162         if (*p == '%') formatted_path_len += home_len - 1;
1163         ++formatted_path_len;
1164     }
1165 
1166     char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal);
1167     if (formatted_path == NULL) {
1168         return NULL;
1169     }
1170 
1171     // Create boot classpath from format, substituting separator chars and
1172     // java home directory.
1173     char* q = formatted_path;
1174     for (p = format_string; *p != 0; ++p) {
1175         switch (*p) {
1176         case '%':
1177             strcpy(q, home);
1178             q += home_len;
1179             break;
1180         case '/':
1181             *q++ = fileSep;
1182             break;
1183         case ':':
1184             *q++ = pathSep;
1185             break;
1186         default:
1187             *q++ = *p;
1188         }
1189     }
1190     *q = '\0';
1191 
1192     assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
1193     return formatted_path;
1194 }
1195 
1196 // returns a PATH of all entries in the given directory that do not start with a '.'
1197 static char* expand_entries_to_path(char* directory, char fileSep, char pathSep) {
1198   DIR* dir = os::opendir(directory);
1199   if (dir == NULL) return NULL;
1200 
1201   char* path = NULL;
1202   size_t path_len = 0;  // path length including \0 terminator
1203 
1204   size_t directory_len = strlen(directory);
1205   struct dirent *entry;
1206   char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(directory), mtInternal);
1207   while ((entry = os::readdir(dir, (dirent *) dbuf)) != NULL) {
1208     const char* name = entry->d_name;
1209     if (name[0] == '.') continue;
1210 
1211     size_t name_len = strlen(name);
1212     size_t needed = directory_len + name_len + 2;
1213     size_t new_len = path_len + needed;
1214     if (path == NULL) {
1215       path = NEW_C_HEAP_ARRAY(char, new_len, mtInternal);
1216     } else {
1217       path = REALLOC_C_HEAP_ARRAY(char, path, new_len, mtInternal);
1218     }
1219     if (path == NULL)
1220       break;
1221 
1222     // append <pathSep>directory<fileSep>name
1223     char* p = path;
1224     if (path_len > 0) {
1225       p += (path_len -1);
1226       *p = pathSep;
1227       p++;
1228     }
1229 
1230     strcpy(p, directory);
1231     p += directory_len;
1232 
1233     *p = fileSep;
1234     p++;
1235 
1236     strcpy(p, name);
1237     p += name_len;
1238 
1239     path_len = new_len;
1240   }
1241 
1242   FREE_C_HEAP_ARRAY(char, dbuf);
1243   os::closedir(dir);
1244 
1245   return path;
1246 }
1247 
1248 bool os::set_boot_path(char fileSep, char pathSep) {
1249   const char* home = Arguments::get_java_home();
1250   int home_len = (int)strlen(home);
1251 
1252   char* sysclasspath = NULL;
1253   struct stat st;
1254 
1255   // modular image if bootmodules.jimage exists
1256   char* jimage = format_boot_path("%/lib/modules/" BOOT_IMAGE_NAME, home, home_len, fileSep, pathSep);
1257   if (jimage == NULL) return false;
1258   bool has_jimage = (os::stat(jimage, &st) == 0);
1259   if (has_jimage) {
1260     Arguments::set_sysclasspath(jimage);
1261     FREE_C_HEAP_ARRAY(char, jimage);
1262     return true;
1263   }
1264   FREE_C_HEAP_ARRAY(char, jimage);
1265 
1266   // check if developer build with exploded modules
1267   char* modules_dir = format_boot_path("%/modules", home, home_len, fileSep, pathSep);
1268   if (os::stat(modules_dir, &st) == 0) {
1269     if ((st.st_mode & S_IFDIR) == S_IFDIR) {
1270       sysclasspath = expand_entries_to_path(modules_dir, fileSep, pathSep);
1271     }
1272   }
1273   FREE_C_HEAP_ARRAY(char, modules_dir);
1274 
1275   // fallback to classes
1276   if (sysclasspath == NULL)
1277     sysclasspath = format_boot_path("%/classes", home, home_len, fileSep, pathSep);
1278 
1279   if (sysclasspath == NULL) return false;
1280   Arguments::set_sysclasspath(sysclasspath);
1281   FREE_C_HEAP_ARRAY(char, sysclasspath);
1282 
1283   return true;
1284 }
1285 
1286 /*
1287  * Splits a path, based on its separator, the number of
1288  * elements is returned back in n.
1289  * It is the callers responsibility to:
1290  *   a> check the value of n, and n may be 0.
1291  *   b> ignore any empty path elements
1292  *   c> free up the data.
1293  */
1294 char** os::split_path(const char* path, int* n) {
1295   *n = 0;
1296   if (path == NULL || strlen(path) == 0) {
1297     return NULL;
1298   }
1299   const char psepchar = *os::path_separator();
1300   char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal);
1301   if (inpath == NULL) {
1302     return NULL;
1303   }
1304   strcpy(inpath, path);
1305   int count = 1;
1306   char* p = strchr(inpath, psepchar);
1307   // Get a count of elements to allocate memory
1308   while (p != NULL) {
1309     count++;
1310     p++;
1311     p = strchr(p, psepchar);
1312   }
1313   char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count, mtInternal);
1314   if (opath == NULL) {
1315     return NULL;
1316   }
1317 
1318   // do the actual splitting
1319   p = inpath;
1320   for (int i = 0 ; i < count ; i++) {
1321     size_t len = strcspn(p, os::path_separator());
1322     if (len > JVM_MAXPATHLEN) {
1323       return NULL;
1324     }
1325     // allocate the string and add terminator storage
1326     char* s  = (char*)NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
1327     if (s == NULL) {
1328       return NULL;
1329     }
1330     strncpy(s, p, len);
1331     s[len] = '\0';
1332     opath[i] = s;
1333     p += len + 1;
1334   }
1335   FREE_C_HEAP_ARRAY(char, inpath);
1336   *n = count;
1337   return opath;
1338 }
1339 
1340 void os::set_memory_serialize_page(address page) {
1341   int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64);
1342   _mem_serialize_page = (volatile int32_t *)page;
1343   // We initialize the serialization page shift count here
1344   // We assume a cache line size of 64 bytes
1345   assert(SerializePageShiftCount == count,
1346          "thread size changed, fix SerializePageShiftCount constant");
1347   set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t)));
1348 }
1349 
1350 static volatile intptr_t SerializePageLock = 0;
1351 
1352 // This method is called from signal handler when SIGSEGV occurs while the current
1353 // thread tries to store to the "read-only" memory serialize page during state
1354 // transition.
1355 void os::block_on_serialize_page_trap() {
1356   log_debug(safepoint)("Block until the serialize page permission restored");
1357 
1358   // When VMThread is holding the SerializePageLock during modifying the
1359   // access permission of the memory serialize page, the following call
1360   // will block until the permission of that page is restored to rw.
1361   // Generally, it is unsafe to manipulate locks in signal handlers, but in
1362   // this case, it's OK as the signal is synchronous and we know precisely when
1363   // it can occur.
1364   Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page");
1365   Thread::muxRelease(&SerializePageLock);
1366 }
1367 
1368 // Serialize all thread state variables
1369 void os::serialize_thread_states() {
1370   // On some platforms such as Solaris & Linux, the time duration of the page
1371   // permission restoration is observed to be much longer than expected  due to
1372   // scheduler starvation problem etc. To avoid the long synchronization
1373   // time and expensive page trap spinning, 'SerializePageLock' is used to block
1374   // the mutator thread if such case is encountered. See bug 6546278 for details.
1375   Thread::muxAcquire(&SerializePageLock, "serialize_thread_states");
1376   os::protect_memory((char *)os::get_memory_serialize_page(),
1377                      os::vm_page_size(), MEM_PROT_READ);
1378   os::protect_memory((char *)os::get_memory_serialize_page(),
1379                      os::vm_page_size(), MEM_PROT_RW);
1380   Thread::muxRelease(&SerializePageLock);
1381 }
1382 
1383 // Returns true if the current stack pointer is above the stack shadow
1384 // pages, false otherwise.
1385 bool os::stack_shadow_pages_available(Thread *thread, const methodHandle& method) {
1386   if (!thread->is_Java_thread()) return false;
1387   address sp = current_stack_pointer();
1388   // Check if we have StackShadowPages above the yellow zone.  This parameter
1389   // is dependent on the depth of the maximum VM call stack possible from
1390   // the handler for stack overflow.  'instanceof' in the stack overflow
1391   // handler or a println uses at least 8k stack of VM and native code
1392   // respectively.
1393   const int framesize_in_bytes =
1394     Interpreter::size_top_interpreter_activation(method()) * wordSize;
1395 
1396   assert((thread->stack_base() - thread->stack_size()) +
1397          (JavaThread::stack_guard_zone_size() +
1398           JavaThread::stack_shadow_zone_size() + framesize_in_bytes) ==
1399          ((JavaThread*)thread)->stack_overflow_limit() + framesize_in_bytes, "sanity");
1400 
1401   return (sp > ((JavaThread*)thread)->stack_overflow_limit() + framesize_in_bytes);
1402 }
1403 
1404 size_t os::page_size_for_region(size_t region_size, size_t min_pages, bool must_be_aligned) {
1405   assert(min_pages > 0, "sanity");
1406   if (UseLargePages) {
1407     const size_t max_page_size = region_size / min_pages;
1408 
1409     for (size_t i = 0; _page_sizes[i] != 0; ++i) {
1410       const size_t page_size = _page_sizes[i];
1411       if (page_size <= max_page_size) {
1412         if (!must_be_aligned || is_size_aligned(region_size, page_size)) {
1413           return page_size;
1414         }
1415       }
1416     }
1417   }
1418 
1419   return vm_page_size();
1420 }
1421 
1422 size_t os::page_size_for_region_aligned(size_t region_size, size_t min_pages) {
1423   return page_size_for_region(region_size, min_pages, true);
1424 }
1425 
1426 size_t os::page_size_for_region_unaligned(size_t region_size, size_t min_pages) {
1427   return page_size_for_region(region_size, min_pages, false);
1428 }
1429 
1430 #ifndef PRODUCT
1431 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count)
1432 {
1433   if (TracePageSizes) {
1434     tty->print("%s: ", str);
1435     for (int i = 0; i < count; ++i) {
1436       tty->print(" " SIZE_FORMAT, page_sizes[i]);
1437     }
1438     tty->cr();
1439   }
1440 }
1441 
1442 void os::trace_page_sizes(const char* str, const size_t region_min_size,
1443                           const size_t region_max_size, const size_t page_size,
1444                           const char* base, const size_t size)
1445 {
1446   if (TracePageSizes) {
1447     tty->print_cr("%s:  min=" SIZE_FORMAT " max=" SIZE_FORMAT
1448                   " pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT
1449                   " size=" SIZE_FORMAT,
1450                   str, region_min_size, region_max_size,
1451                   page_size, p2i(base), size);
1452   }
1453 }
1454 #endif  // #ifndef PRODUCT
1455 
1456 // This is the working definition of a server class machine:
1457 // >= 2 physical CPU's and >=2GB of memory, with some fuzz
1458 // because the graphics memory (?) sometimes masks physical memory.
1459 // If you want to change the definition of a server class machine
1460 // on some OS or platform, e.g., >=4GB on Windows platforms,
1461 // then you'll have to parameterize this method based on that state,
1462 // as was done for logical processors here, or replicate and
1463 // specialize this method for each platform.  (Or fix os to have
1464 // some inheritance structure and use subclassing.  Sigh.)
1465 // If you want some platform to always or never behave as a server
1466 // class machine, change the setting of AlwaysActAsServerClassMachine
1467 // and NeverActAsServerClassMachine in globals*.hpp.
1468 bool os::is_server_class_machine() {
1469   // First check for the early returns
1470   if (NeverActAsServerClassMachine) {
1471     return false;
1472   }
1473   if (AlwaysActAsServerClassMachine) {
1474     return true;
1475   }
1476   // Then actually look at the machine
1477   bool         result            = false;
1478   const unsigned int    server_processors = 2;
1479   const julong server_memory     = 2UL * G;
1480   // We seem not to get our full complement of memory.
1481   //     We allow some part (1/8?) of the memory to be "missing",
1482   //     based on the sizes of DIMMs, and maybe graphics cards.
1483   const julong missing_memory   = 256UL * M;
1484 
1485   /* Is this a server class machine? */
1486   if ((os::active_processor_count() >= (int)server_processors) &&
1487       (os::physical_memory() >= (server_memory - missing_memory))) {
1488     const unsigned int logical_processors =
1489       VM_Version::logical_processors_per_package();
1490     if (logical_processors > 1) {
1491       const unsigned int physical_packages =
1492         os::active_processor_count() / logical_processors;
1493       if (physical_packages >= server_processors) {
1494         result = true;
1495       }
1496     } else {
1497       result = true;
1498     }
1499   }
1500   return result;
1501 }
1502 
1503 void os::SuspendedThreadTask::run() {
1504   assert(Threads_lock->owned_by_self() || (_thread == VMThread::vm_thread()), "must have threads lock to call this");
1505   internal_do_task();
1506   _done = true;
1507 }
1508 
1509 bool os::create_stack_guard_pages(char* addr, size_t bytes) {
1510   return os::pd_create_stack_guard_pages(addr, bytes);
1511 }
1512 
1513 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint) {
1514   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1515   if (result != NULL) {
1516     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1517   }
1518 
1519   return result;
1520 }
1521 
1522 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint,
1523    MEMFLAGS flags) {
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     MemTracker::record_virtual_memory_type((address)result, flags);
1528   }
1529 
1530   return result;
1531 }
1532 
1533 char* os::attempt_reserve_memory_at(size_t bytes, char* addr) {
1534   char* result = pd_attempt_reserve_memory_at(bytes, addr);
1535   if (result != NULL) {
1536     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1537   }
1538   return result;
1539 }
1540 
1541 void os::split_reserved_memory(char *base, size_t size,
1542                                  size_t split, bool realloc) {
1543   pd_split_reserved_memory(base, size, split, realloc);
1544 }
1545 
1546 bool os::commit_memory(char* addr, size_t bytes, bool executable) {
1547   bool res = pd_commit_memory(addr, bytes, executable);
1548   if (res) {
1549     MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1550   }
1551   return res;
1552 }
1553 
1554 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
1555                               bool executable) {
1556   bool res = os::pd_commit_memory(addr, size, alignment_hint, executable);
1557   if (res) {
1558     MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1559   }
1560   return res;
1561 }
1562 
1563 void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable,
1564                                const char* mesg) {
1565   pd_commit_memory_or_exit(addr, bytes, executable, mesg);
1566   MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1567 }
1568 
1569 void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint,
1570                                bool executable, const char* mesg) {
1571   os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg);
1572   MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1573 }
1574 
1575 bool os::uncommit_memory(char* addr, size_t bytes) {
1576   bool res;
1577   if (MemTracker::tracking_level() > NMT_minimal) {
1578     Tracker tkr = MemTracker::get_virtual_memory_uncommit_tracker();
1579     res = pd_uncommit_memory(addr, bytes);
1580     if (res) {
1581       tkr.record((address)addr, bytes);
1582     }
1583   } else {
1584     res = pd_uncommit_memory(addr, bytes);
1585   }
1586   return res;
1587 }
1588 
1589 bool os::release_memory(char* addr, size_t bytes) {
1590   bool res;
1591   if (MemTracker::tracking_level() > NMT_minimal) {
1592     Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1593     res = pd_release_memory(addr, bytes);
1594     if (res) {
1595       tkr.record((address)addr, bytes);
1596     }
1597   } else {
1598     res = pd_release_memory(addr, bytes);
1599   }
1600   return res;
1601 }
1602 
1603 void os::pretouch_memory(char* start, char* end) {
1604   for (volatile char *p = start; p < end; p += os::vm_page_size()) {
1605     *p = 0;
1606   }
1607 }
1608 
1609 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
1610                            char *addr, size_t bytes, bool read_only,
1611                            bool allow_exec) {
1612   char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec);
1613   if (result != NULL) {
1614     MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1615   }
1616   return result;
1617 }
1618 
1619 char* os::remap_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   return pd_remap_memory(fd, file_name, file_offset, addr, bytes,
1623                     read_only, allow_exec);
1624 }
1625 
1626 bool os::unmap_memory(char *addr, size_t bytes) {
1627   bool result;
1628   if (MemTracker::tracking_level() > NMT_minimal) {
1629     Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1630     result = pd_unmap_memory(addr, bytes);
1631     if (result) {
1632       tkr.record((address)addr, bytes);
1633     }
1634   } else {
1635     result = pd_unmap_memory(addr, bytes);
1636   }
1637   return result;
1638 }
1639 
1640 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
1641   pd_free_memory(addr, bytes, alignment_hint);
1642 }
1643 
1644 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
1645   pd_realign_memory(addr, bytes, alignment_hint);
1646 }
1647 
1648 #ifndef TARGET_OS_FAMILY_windows
1649 /* try to switch state from state "from" to state "to"
1650  * returns the state set after the method is complete
1651  */
1652 os::SuspendResume::State os::SuspendResume::switch_state(os::SuspendResume::State from,
1653                                                          os::SuspendResume::State to)
1654 {
1655   os::SuspendResume::State result =
1656     (os::SuspendResume::State) Atomic::cmpxchg((jint) to, (jint *) &_state, (jint) from);
1657   if (result == from) {
1658     // success
1659     return to;
1660   }
1661   return result;
1662 }
1663 #endif
1664 
1665 /////////////// Unit tests ///////////////
1666 
1667 #ifndef PRODUCT
1668 
1669 #define assert_eq(a,b) assert(a == b, SIZE_FORMAT " != " SIZE_FORMAT, a, b)
1670 
1671 class TestOS : AllStatic {
1672   static size_t small_page_size() {
1673     return os::vm_page_size();
1674   }
1675 
1676   static size_t large_page_size() {
1677     const size_t large_page_size_example = 4 * M;
1678     return os::page_size_for_region_aligned(large_page_size_example, 1);
1679   }
1680 
1681   static void test_page_size_for_region_aligned() {
1682     if (UseLargePages) {
1683       const size_t small_page = small_page_size();
1684       const size_t large_page = large_page_size();
1685 
1686       if (large_page > small_page) {
1687         size_t num_small_pages_in_large = large_page / small_page;
1688         size_t page = os::page_size_for_region_aligned(large_page, num_small_pages_in_large);
1689 
1690         assert_eq(page, small_page);
1691       }
1692     }
1693   }
1694 
1695   static void test_page_size_for_region_alignment() {
1696     if (UseLargePages) {
1697       const size_t small_page = small_page_size();
1698       const size_t large_page = large_page_size();
1699       if (large_page > small_page) {
1700         const size_t unaligned_region = large_page + 17;
1701         size_t page = os::page_size_for_region_aligned(unaligned_region, 1);
1702         assert_eq(page, small_page);
1703 
1704         const size_t num_pages = 5;
1705         const size_t aligned_region = large_page * num_pages;
1706         page = os::page_size_for_region_aligned(aligned_region, num_pages);
1707         assert_eq(page, large_page);
1708       }
1709     }
1710   }
1711 
1712   static void test_page_size_for_region_unaligned() {
1713     if (UseLargePages) {
1714       // Given exact page size, should return that page size.
1715       for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
1716         size_t expected = os::_page_sizes[i];
1717         size_t actual = os::page_size_for_region_unaligned(expected, 1);
1718         assert_eq(expected, actual);
1719       }
1720 
1721       // Given slightly larger size than a page size, return the page size.
1722       for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
1723         size_t expected = os::_page_sizes[i];
1724         size_t actual = os::page_size_for_region_unaligned(expected + 17, 1);
1725         assert_eq(expected, actual);
1726       }
1727 
1728       // Given a slightly smaller size than a page size,
1729       // return the next smaller page size.
1730       if (os::_page_sizes[1] > os::_page_sizes[0]) {
1731         size_t expected = os::_page_sizes[0];
1732         size_t actual = os::page_size_for_region_unaligned(os::_page_sizes[1] - 17, 1);
1733         assert_eq(actual, expected);
1734       }
1735 
1736       // Return small page size for values less than a small page.
1737       size_t small_page = small_page_size();
1738       size_t actual = os::page_size_for_region_unaligned(small_page - 17, 1);
1739       assert_eq(small_page, actual);
1740     }
1741   }
1742 
1743  public:
1744   static void run_tests() {
1745     test_page_size_for_region_aligned();
1746     test_page_size_for_region_alignment();
1747     test_page_size_for_region_unaligned();
1748   }
1749 };
1750 
1751 void TestOS_test() {
1752   TestOS::run_tests();
1753 }
1754 
1755 #endif // PRODUCT