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/icBuffer.hpp"
  31 #include "code/vtableStubs.hpp"
  32 #include "gc_implementation/shared/vmGCOperations.hpp"
  33 #include "interpreter/interpreter.hpp"
  34 #include "memory/allocation.inline.hpp"
  35 #ifdef ASSERT
  36 #include "memory/guardedMemory.hpp"
  37 #endif
  38 #include "oops/oop.inline.hpp"
  39 #include "prims/jvm.h"
  40 #include "prims/jvm_misc.hpp"
  41 #include "prims/privilegedStack.hpp"
  42 #include "runtime/arguments.hpp"
  43 #include "runtime/frame.inline.hpp"
  44 #include "runtime/interfaceSupport.hpp"
  45 #include "runtime/java.hpp"
  46 #include "runtime/javaCalls.hpp"
  47 #include "runtime/mutexLocker.hpp"
  48 #include "runtime/os.hpp"
  49 #include "runtime/stubRoutines.hpp"
  50 #include "runtime/thread.inline.hpp"
  51 #include "services/attachListener.hpp"
  52 #include "services/nmtCommon.hpp"
  53 #include "services/mallocTracker.hpp"
  54 #include "services/memTracker.hpp"
  55 #include "services/threadService.hpp"
  56 #include "utilities/defaultStream.hpp"
  57 #include "utilities/events.hpp"
  58 #ifdef TARGET_OS_FAMILY_linux
  59 # include "os_linux.inline.hpp"
  60 #endif
  61 #ifdef TARGET_OS_FAMILY_solaris
  62 # include "os_solaris.inline.hpp"
  63 #endif
  64 #ifdef TARGET_OS_FAMILY_windows
  65 # include "os_windows.inline.hpp"
  66 #endif
  67 #ifdef TARGET_OS_FAMILY_bsd
  68 # include "os_bsd.inline.hpp"
  69 #endif
  70 
  71 # include <signal.h>
  72 
  73 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  74 
  75 OSThread*         os::_starting_thread    = NULL;
  76 address           os::_polling_page       = NULL;
  77 volatile int32_t* os::_mem_serialize_page = NULL;
  78 uintptr_t         os::_serialize_page_mask = 0;
  79 long              os::_rand_seed          = 1;
  80 int               os::_processor_count    = 0;
  81 int               os::_initial_active_processor_count = 0;
  82 size_t            os::_page_sizes[os::page_sizes_max];
  83 
  84 #ifndef PRODUCT
  85 julong os::num_mallocs = 0;         // # of calls to malloc/realloc
  86 julong os::alloc_bytes = 0;         // # of bytes allocated
  87 julong os::num_frees = 0;           // # of calls to free
  88 julong os::free_bytes = 0;          // # of bytes freed
  89 #endif
  90 
  91 static juint cur_malloc_words = 0;  // current size for MallocMaxTestWords
  92 
  93 void os_init_globals() {
  94   // Called from init_globals().
  95   // See Threads::create_vm() in thread.cpp, and init.cpp.
  96   os::init_globals();
  97 }
  98 
  99 // Fill in buffer with current local time as an ISO-8601 string.
 100 // E.g., yyyy-mm-ddThh:mm:ss-zzzz.
 101 // Returns buffer, or NULL if it failed.
 102 // This would mostly be a call to
 103 //     strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
 104 // except that on Windows the %z behaves badly, so we do it ourselves.
 105 // Also, people wanted milliseconds on there,
 106 // and strftime doesn't do milliseconds.
 107 char* os::iso8601_time(char* buffer, size_t buffer_length) {
 108   // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
 109   //                                      1         2
 110   //                             12345678901234567890123456789
 111   static const char* iso8601_format =
 112     "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d";
 113   static const size_t needed_buffer = 29;
 114 
 115   // Sanity check the arguments
 116   if (buffer == NULL) {
 117     assert(false, "NULL buffer");
 118     return NULL;
 119   }
 120   if (buffer_length < needed_buffer) {
 121     assert(false, "buffer_length too small");
 122     return NULL;
 123   }
 124   // Get the current time
 125   jlong milliseconds_since_19700101 = javaTimeMillis();
 126   const int milliseconds_per_microsecond = 1000;
 127   const time_t seconds_since_19700101 =
 128     milliseconds_since_19700101 / milliseconds_per_microsecond;
 129   const int milliseconds_after_second =
 130     milliseconds_since_19700101 % milliseconds_per_microsecond;
 131   // Convert the time value to a tm and timezone variable
 132   struct tm time_struct;
 133   if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
 134     assert(false, "Failed localtime_pd");
 135     return NULL;
 136   }
 137 #if defined(_ALLBSD_SOURCE)
 138   const time_t zone = (time_t) time_struct.tm_gmtoff;
 139 #else
 140   const time_t zone = timezone;
 141 #endif
 142 
 143   // If daylight savings time is in effect,
 144   // we are 1 hour East of our time zone
 145   const time_t seconds_per_minute = 60;
 146   const time_t minutes_per_hour = 60;
 147   const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
 148   time_t UTC_to_local = zone;
 149   if (time_struct.tm_isdst > 0) {
 150     UTC_to_local = UTC_to_local - seconds_per_hour;
 151   }
 152   // Compute the time zone offset.
 153   //    localtime_pd() sets timezone to the difference (in seconds)
 154   //    between UTC and and local time.
 155   //    ISO 8601 says we need the difference between local time and UTC,
 156   //    we change the sign of the localtime_pd() result.
 157   const time_t local_to_UTC = -(UTC_to_local);
 158   // Then we have to figure out if if we are ahead (+) or behind (-) UTC.
 159   char sign_local_to_UTC = '+';
 160   time_t abs_local_to_UTC = local_to_UTC;
 161   if (local_to_UTC < 0) {
 162     sign_local_to_UTC = '-';
 163     abs_local_to_UTC = -(abs_local_to_UTC);
 164   }
 165   // Convert time zone offset seconds to hours and minutes.
 166   const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
 167   const time_t zone_min =
 168     ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
 169 
 170   // Print an ISO 8601 date and time stamp into the buffer
 171   const int year = 1900 + time_struct.tm_year;
 172   const int month = 1 + time_struct.tm_mon;
 173   const int printed = jio_snprintf(buffer, buffer_length, iso8601_format,
 174                                    year,
 175                                    month,
 176                                    time_struct.tm_mday,
 177                                    time_struct.tm_hour,
 178                                    time_struct.tm_min,
 179                                    time_struct.tm_sec,
 180                                    milliseconds_after_second,
 181                                    sign_local_to_UTC,
 182                                    zone_hours,
 183                                    zone_min);
 184   if (printed == 0) {
 185     assert(false, "Failed jio_printf");
 186     return NULL;
 187   }
 188   return buffer;
 189 }
 190 
 191 OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
 192 #ifdef ASSERT
 193   if (!(!thread->is_Java_thread() ||
 194          Thread::current() == thread  ||
 195          Threads_lock->owned_by_self()
 196          || thread->is_Compiler_thread()
 197         )) {
 198     assert(false, "possibility of dangling Thread pointer");
 199   }
 200 #endif
 201 
 202   if (p >= MinPriority && p <= MaxPriority) {
 203     int priority = java_to_os_priority[p];
 204     return set_native_priority(thread, priority);
 205   } else {
 206     assert(false, "Should not happen");
 207     return OS_ERR;
 208   }
 209 }
 210 
 211 // The mapping from OS priority back to Java priority may be inexact because
 212 // Java priorities can map M:1 with native priorities. If you want the definite
 213 // Java priority then use JavaThread::java_priority()
 214 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
 215   int p;
 216   int os_prio;
 217   OSReturn ret = get_native_priority(thread, &os_prio);
 218   if (ret != OS_OK) return ret;
 219 
 220   if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) {
 221     for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
 222   } else {
 223     // niceness values are in reverse order
 224     for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] < os_prio; p--) ;
 225   }
 226   priority = (ThreadPriority)p;
 227   return OS_OK;
 228 }
 229 
 230 
 231 // --------------------- sun.misc.Signal (optional) ---------------------
 232 
 233 
 234 // SIGBREAK is sent by the keyboard to query the VM state
 235 #ifndef SIGBREAK
 236 #define SIGBREAK SIGQUIT
 237 #endif
 238 
 239 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
 240 
 241 
 242 static void signal_thread_entry(JavaThread* thread, TRAPS) {
 243   os::set_priority(thread, NearMaxPriority);
 244   while (true) {
 245     int sig;
 246     {
 247       // FIXME : Currently we have not decieded what should be the status
 248       //         for this java thread blocked here. Once we decide about
 249       //         that we should fix this.
 250       sig = os::signal_wait();
 251     }
 252     if (sig == os::sigexitnum_pd()) {
 253        // Terminate the signal thread
 254        return;
 255     }
 256 
 257     switch (sig) {
 258       case SIGBREAK: {
 259         // Check if the signal is a trigger to start the Attach Listener - in that
 260         // case don't print stack traces.
 261         if (!DisableAttachMechanism && AttachListener::is_init_trigger()) {
 262           continue;
 263         }
 264         // Print stack traces
 265         // Any SIGBREAK operations added here should make sure to flush
 266         // the output stream (e.g. tty->flush()) after output.  See 4803766.
 267         // Each module also prints an extra carriage return after its output.
 268         VM_PrintThreads op;
 269         VMThread::execute(&op);
 270         VM_PrintJNI jni_op;
 271         VMThread::execute(&jni_op);
 272         VM_FindDeadlocks op1(tty);
 273         VMThread::execute(&op1);
 274         Universe::print_heap_at_SIGBREAK();
 275         if (PrintClassHistogram) {
 276           VM_GC_HeapInspection op1(gclog_or_tty, true /* force full GC before heap inspection */);
 277           VMThread::execute(&op1);
 278         }
 279         if (JvmtiExport::should_post_data_dump()) {
 280           JvmtiExport::post_data_dump();
 281         }
 282         break;
 283       }
 284       default: {
 285         // Dispatch the signal to java
 286         HandleMark hm(THREAD);
 287         Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_Signal(), THREAD);
 288         KlassHandle klass (THREAD, k);
 289         if (klass.not_null()) {
 290           JavaValue result(T_VOID);
 291           JavaCallArguments args;
 292           args.push_int(sig);
 293           JavaCalls::call_static(
 294             &result,
 295             klass,
 296             vmSymbols::dispatch_name(),
 297             vmSymbols::int_void_signature(),
 298             &args,
 299             THREAD
 300           );
 301         }
 302         if (HAS_PENDING_EXCEPTION) {
 303           // tty is initialized early so we don't expect it to be null, but
 304           // if it is we can't risk doing an initialization that might
 305           // trigger additional out-of-memory conditions
 306           if (tty != NULL) {
 307             char klass_name[256];
 308             char tmp_sig_name[16];
 309             const char* sig_name = "UNKNOWN";
 310             InstanceKlass::cast(PENDING_EXCEPTION->klass())->
 311               name()->as_klass_external_name(klass_name, 256);
 312             if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
 313               sig_name = tmp_sig_name;
 314             warning("Exception %s occurred dispatching signal %s to handler"
 315                     "- the VM may need to be forcibly terminated",
 316                     klass_name, sig_name );
 317           }
 318           CLEAR_PENDING_EXCEPTION;
 319         }
 320       }
 321     }
 322   }
 323 }
 324 
 325 void os::init_before_ergo() {
 326   initialize_initial_active_processor_count();
 327   // We need to initialize large page support here because ergonomics takes some
 328   // decisions depending on large page support and the calculated large page size.
 329   large_page_init();
 330 
 331   // VM version initialization identifies some characteristics of the
 332   // the platform that are used during ergonomic decisions.
 333   VM_Version::init_before_ergo();
 334 }
 335 
 336 void os::signal_init() {
 337   if (!ReduceSignalUsage) {
 338     // Setup JavaThread for processing signals
 339     EXCEPTION_MARK;
 340     Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
 341     instanceKlassHandle klass (THREAD, k);
 342     instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
 343 
 344     const char thread_name[] = "Signal Dispatcher";
 345     Handle string = java_lang_String::create_from_str(thread_name, CHECK);
 346 
 347     // Initialize thread_oop to put it into the system threadGroup
 348     Handle thread_group (THREAD, Universe::system_thread_group());
 349     JavaValue result(T_VOID);
 350     JavaCalls::call_special(&result, thread_oop,
 351                            klass,
 352                            vmSymbols::object_initializer_name(),
 353                            vmSymbols::threadgroup_string_void_signature(),
 354                            thread_group,
 355                            string,
 356                            CHECK);
 357 
 358     KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
 359     JavaCalls::call_special(&result,
 360                             thread_group,
 361                             group,
 362                             vmSymbols::add_method_name(),
 363                             vmSymbols::thread_void_signature(),
 364                             thread_oop,         // ARG 1
 365                             CHECK);
 366 
 367     os::signal_init_pd();
 368 
 369     { MutexLocker mu(Threads_lock);
 370       JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
 371 
 372       // At this point it may be possible that no osthread was created for the
 373       // JavaThread due to lack of memory. We would have to throw an exception
 374       // in that case. However, since this must work and we do not allow
 375       // exceptions anyway, check and abort if this fails.
 376       if (signal_thread == NULL || signal_thread->osthread() == NULL) {
 377         vm_exit_during_initialization("java.lang.OutOfMemoryError",
 378                                       "unable to create new native thread");
 379       }
 380 
 381       java_lang_Thread::set_thread(thread_oop(), signal_thread);
 382       java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
 383       java_lang_Thread::set_daemon(thread_oop());
 384 
 385       signal_thread->set_threadObj(thread_oop());
 386       Threads::add(signal_thread);
 387       Thread::start(signal_thread);
 388     }
 389     // Handle ^BREAK
 390     os::signal(SIGBREAK, os::user_handler());
 391   }
 392 }
 393 
 394 
 395 void os::terminate_signal_thread() {
 396   if (!ReduceSignalUsage)
 397     signal_notify(sigexitnum_pd());
 398 }
 399 
 400 
 401 // --------------------- loading libraries ---------------------
 402 
 403 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
 404 extern struct JavaVM_ main_vm;
 405 
 406 static void* _native_java_library = NULL;
 407 
 408 void* os::native_java_library() {
 409   if (_native_java_library == NULL) {
 410     char buffer[JVM_MAXPATHLEN];
 411     char ebuf[1024];
 412 
 413     // Try to load verify dll first. In 1.3 java dll depends on it and is not
 414     // always able to find it when the loading executable is outside the JDK.
 415     // In order to keep working with 1.2 we ignore any loading errors.
 416     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 417                        "verify")) {
 418       dll_load(buffer, ebuf, sizeof(ebuf));
 419     }
 420 
 421     // Load java dll
 422     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 423                        "java")) {
 424       _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
 425     }
 426     if (_native_java_library == NULL) {
 427       vm_exit_during_initialization("Unable to load native library", ebuf);
 428     }
 429 
 430 #if defined(__OpenBSD__)
 431     // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so
 432     // ignore errors
 433     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 434                        "net")) {
 435       dll_load(buffer, ebuf, sizeof(ebuf));
 436     }
 437 #endif
 438   }
 439   static jboolean onLoaded = JNI_FALSE;
 440   if (onLoaded) {
 441     // We may have to wait to fire OnLoad until TLS is initialized.
 442     if (ThreadLocalStorage::is_initialized()) {
 443       // The JNI_OnLoad handling is normally done by method load in
 444       // java.lang.ClassLoader$NativeLibrary, but the VM loads the base library
 445       // explicitly so we have to check for JNI_OnLoad as well
 446       const char *onLoadSymbols[] = JNI_ONLOAD_SYMBOLS;
 447       JNI_OnLoad_t JNI_OnLoad = CAST_TO_FN_PTR(
 448           JNI_OnLoad_t, dll_lookup(_native_java_library, onLoadSymbols[0]));
 449       if (JNI_OnLoad != NULL) {
 450         JavaThread* thread = JavaThread::current();
 451         ThreadToNativeFromVM ttn(thread);
 452         HandleMark hm(thread);
 453         jint ver = (*JNI_OnLoad)(&main_vm, NULL);
 454         onLoaded = JNI_TRUE;
 455         if (!Threads::is_supported_jni_version_including_1_1(ver)) {
 456           vm_exit_during_initialization("Unsupported JNI version");
 457         }
 458       }
 459     }
 460   }
 461   return _native_java_library;
 462 }
 463 
 464 /*
 465  * Support for finding Agent_On(Un)Load/Attach<_lib_name> if it exists.
 466  * If check_lib == true then we are looking for an
 467  * Agent_OnLoad_lib_name or Agent_OnAttach_lib_name function to determine if
 468  * this library is statically linked into the image.
 469  * If check_lib == false then we will look for the appropriate symbol in the
 470  * executable if agent_lib->is_static_lib() == true or in the shared library
 471  * referenced by 'handle'.
 472  */
 473 void* os::find_agent_function(AgentLibrary *agent_lib, bool check_lib,
 474                               const char *syms[], size_t syms_len) {
 475   assert(agent_lib != NULL, "sanity check");
 476   const char *lib_name;
 477   void *handle = agent_lib->os_lib();
 478   void *entryName = NULL;
 479   char *agent_function_name;
 480   size_t i;
 481 
 482   // If checking then use the agent name otherwise test is_static_lib() to
 483   // see how to process this lookup
 484   lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : NULL);
 485   for (i = 0; i < syms_len; i++) {
 486     agent_function_name = build_agent_function_name(syms[i], lib_name, agent_lib->is_absolute_path());
 487     if (agent_function_name == NULL) {
 488       break;
 489     }
 490     entryName = dll_lookup(handle, agent_function_name);
 491     FREE_C_HEAP_ARRAY(char, agent_function_name, mtThread);
 492     if (entryName != NULL) {
 493       break;
 494     }
 495   }
 496   return entryName;
 497 }
 498 
 499 // See if the passed in agent is statically linked into the VM image.
 500 bool os::find_builtin_agent(AgentLibrary *agent_lib, const char *syms[],
 501                             size_t syms_len) {
 502   void *ret;
 503   void *proc_handle;
 504   void *save_handle;
 505 
 506   assert(agent_lib != NULL, "sanity check");
 507   if (agent_lib->name() == NULL) {
 508     return false;
 509   }
 510   proc_handle = get_default_process_handle();
 511   // Check for Agent_OnLoad/Attach_lib_name function
 512   save_handle = agent_lib->os_lib();
 513   // We want to look in this process' symbol table.
 514   agent_lib->set_os_lib(proc_handle);
 515   ret = find_agent_function(agent_lib, true, syms, syms_len);
 516   if (ret != NULL) {
 517     // Found an entry point like Agent_OnLoad_lib_name so we have a static agent
 518     agent_lib->set_valid();
 519     agent_lib->set_static_lib(true);
 520     return true;
 521   }
 522   agent_lib->set_os_lib(save_handle);
 523   return false;
 524 }
 525 
 526 // --------------------- heap allocation utilities ---------------------
 527 
 528 char *os::strdup(const char *str, MEMFLAGS flags) {
 529   size_t size = strlen(str);
 530   char *dup_str = (char *)malloc(size + 1, flags);
 531   if (dup_str == NULL) return NULL;
 532   strcpy(dup_str, str);
 533   return dup_str;
 534 }
 535 
 536 
 537 
 538 #define paranoid                 0  /* only set to 1 if you suspect checking code has bug */
 539 
 540 #ifdef ASSERT
 541 static void verify_memory(void* ptr) {
 542   GuardedMemory guarded(ptr);
 543   if (!guarded.verify_guards()) {
 544     tty->print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees);
 545     tty->print_cr("## memory stomp:");
 546     guarded.print_on(tty);
 547     fatal("memory stomping error");
 548   }
 549 }
 550 #endif
 551 
 552 //
 553 // This function supports testing of the malloc out of memory
 554 // condition without really running the system out of memory.
 555 //
 556 static u_char* testMalloc(size_t alloc_size) {
 557   assert(MallocMaxTestWords > 0, "sanity check");
 558 
 559   if ((cur_malloc_words + (alloc_size / BytesPerWord)) > MallocMaxTestWords) {
 560     return NULL;
 561   }
 562 
 563   u_char* ptr = (u_char*)::malloc(alloc_size);
 564 
 565   if (ptr != NULL) {
 566     Atomic::add(((jint) (alloc_size / BytesPerWord)),
 567                 (volatile jint *) &cur_malloc_words);
 568   }
 569   return ptr;
 570 }
 571 
 572 void* os::malloc(size_t size, MEMFLAGS flags) {
 573   return os::malloc(size, flags, CALLER_PC);
 574 }
 575 
 576 void* os::malloc(size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
 577   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 578   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 579 
 580 #ifdef ASSERT
 581   // checking for the WatcherThread and crash_protection first
 582   // since os::malloc can be called when the libjvm.{dll,so} is
 583   // first loaded and we don't have a thread yet.
 584   // try to find the thread after we see that the watcher thread
 585   // exists and has crash protection.
 586   WatcherThread *wt = WatcherThread::watcher_thread();
 587   if (wt != NULL && wt->has_crash_protection()) {
 588     Thread* thread = ThreadLocalStorage::get_thread_slow();
 589     if (thread == wt) {
 590       assert(!wt->has_crash_protection(),
 591           "Can't malloc with crash protection from WatcherThread");
 592     }
 593   }
 594 #endif
 595 
 596   if (size == 0) {
 597     // return a valid pointer if size is zero
 598     // if NULL is returned the calling functions assume out of memory.
 599     size = 1;
 600   }
 601 
 602   // NMT support
 603   NMT_TrackingLevel level = MemTracker::tracking_level();
 604   size_t            nmt_header_size = MemTracker::malloc_header_size(level);
 605 
 606 #ifndef ASSERT
 607   const size_t alloc_size = size + nmt_header_size;
 608 #else
 609   const size_t alloc_size = GuardedMemory::get_total_size(size + nmt_header_size);
 610   if (size + nmt_header_size > alloc_size) { // Check for rollover.
 611     return NULL;
 612   }
 613 #endif
 614 
 615   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 616 
 617   u_char* ptr;
 618   if (MallocMaxTestWords > 0) {
 619     ptr = testMalloc(alloc_size);
 620   } else {
 621     ptr = (u_char*)::malloc(alloc_size);
 622   }
 623 
 624 #ifdef ASSERT
 625   if (ptr == NULL) {
 626     return NULL;
 627   }
 628   // Wrap memory with guard
 629   GuardedMemory guarded(ptr, size + nmt_header_size);
 630   ptr = guarded.get_user_ptr();
 631 #endif
 632   if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
 633     tty->print_cr("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, ptr);
 634     breakpoint();
 635   }
 636   debug_only(if (paranoid) verify_memory(ptr));
 637   if (PrintMalloc && tty != NULL) {
 638     tty->print_cr("os::malloc " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, ptr);
 639   }
 640 
 641   // we do not track guard memory
 642   return MemTracker::record_malloc((address)ptr, size, memflags, stack, level);
 643 }
 644 
 645 void* os::realloc(void *memblock, size_t size, MEMFLAGS flags) {
 646   return os::realloc(memblock, size, flags, CALLER_PC);
 647 }
 648 
 649 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
 650 
 651 #ifndef ASSERT
 652   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 653   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 654    // NMT support
 655   void* membase = MemTracker::record_free(memblock);
 656   NMT_TrackingLevel level = MemTracker::tracking_level();
 657   size_t  nmt_header_size = MemTracker::malloc_header_size(level);
 658   void* ptr = ::realloc(membase, size + nmt_header_size);
 659   return MemTracker::record_malloc(ptr, size, memflags, stack, level);
 660 #else
 661   if (memblock == NULL) {
 662     return os::malloc(size, memflags, stack);
 663   }
 664   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 665     tty->print_cr("os::realloc caught " PTR_FORMAT, memblock);
 666     breakpoint();
 667   }
 668   // NMT support
 669   void* membase = MemTracker::malloc_base(memblock);
 670   verify_memory(membase);
 671   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 672   if (size == 0) {
 673     return NULL;
 674   }
 675   // always move the block
 676   void* ptr = os::malloc(size, memflags, stack);
 677   if (PrintMalloc) {
 678     tty->print_cr("os::remalloc " SIZE_FORMAT " bytes, " PTR_FORMAT " --> " PTR_FORMAT, size, memblock, ptr);
 679   }
 680   // Copy to new memory if malloc didn't fail
 681   if ( ptr != NULL ) {
 682     GuardedMemory guarded(MemTracker::malloc_base(memblock));
 683     // Guard's user data contains NMT header
 684     size_t memblock_size = guarded.get_user_size() - MemTracker::malloc_header_size(memblock);
 685     memcpy(ptr, memblock, MIN2(size, memblock_size));
 686     if (paranoid) verify_memory(MemTracker::malloc_base(ptr));
 687     if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
 688       tty->print_cr("os::realloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, ptr);
 689       breakpoint();
 690     }
 691     os::free(memblock);
 692   }
 693   return ptr;
 694 #endif
 695 }
 696 
 697 
 698 void  os::free(void *memblock, MEMFLAGS memflags) {
 699   NOT_PRODUCT(inc_stat_counter(&num_frees, 1));
 700 #ifdef ASSERT
 701   if (memblock == NULL) return;
 702   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 703     if (tty != NULL) tty->print_cr("os::free caught " PTR_FORMAT, memblock);
 704     breakpoint();
 705   }
 706   void* membase = MemTracker::record_free(memblock);
 707   verify_memory(membase);
 708   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 709 
 710   GuardedMemory guarded(membase);
 711   size_t size = guarded.get_user_size();
 712   inc_stat_counter(&free_bytes, size);
 713   membase = guarded.release_for_freeing();
 714   if (PrintMalloc && tty != NULL) {
 715       fprintf(stderr, "os::free " SIZE_FORMAT " bytes --> " PTR_FORMAT "\n", size, (uintptr_t)membase);
 716   }
 717   ::free(membase);
 718 #else
 719   void* membase = MemTracker::record_free(memblock);
 720   ::free(membase);
 721 #endif
 722 }
 723 
 724 void os::init_random(long initval) {
 725   _rand_seed = initval;
 726 }
 727 
 728 
 729 long os::random() {
 730   /* standard, well-known linear congruential random generator with
 731    * next_rand = (16807*seed) mod (2**31-1)
 732    * see
 733    * (1) "Random Number Generators: Good Ones Are Hard to Find",
 734    *      S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
 735    * (2) "Two Fast Implementations of the 'Minimal Standard' Random
 736    *     Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
 737   */
 738   const long a = 16807;
 739   const unsigned long m = 2147483647;
 740   const long q = m / a;        assert(q == 127773, "weird math");
 741   const long r = m % a;        assert(r == 2836, "weird math");
 742 
 743   // compute az=2^31p+q
 744   unsigned long lo = a * (long)(_rand_seed & 0xFFFF);
 745   unsigned long hi = a * (long)((unsigned long)_rand_seed >> 16);
 746   lo += (hi & 0x7FFF) << 16;
 747 
 748   // if q overflowed, ignore the overflow and increment q
 749   if (lo > m) {
 750     lo &= m;
 751     ++lo;
 752   }
 753   lo += hi >> 15;
 754 
 755   // if (p+q) overflowed, ignore the overflow and increment (p+q)
 756   if (lo > m) {
 757     lo &= m;
 758     ++lo;
 759   }
 760   return (_rand_seed = lo);
 761 }
 762 
 763 // The INITIALIZED state is distinguished from the SUSPENDED state because the
 764 // conditions in which a thread is first started are different from those in which
 765 // a suspension is resumed.  These differences make it hard for us to apply the
 766 // tougher checks when starting threads that we want to do when resuming them.
 767 // However, when start_thread is called as a result of Thread.start, on a Java
 768 // thread, the operation is synchronized on the Java Thread object.  So there
 769 // cannot be a race to start the thread and hence for the thread to exit while
 770 // we are working on it.  Non-Java threads that start Java threads either have
 771 // to do so in a context in which races are impossible, or should do appropriate
 772 // locking.
 773 
 774 void os::start_thread(Thread* thread) {
 775   // guard suspend/resume
 776   MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
 777   OSThread* osthread = thread->osthread();
 778   osthread->set_state(RUNNABLE);
 779   pd_start_thread(thread);
 780 }
 781 
 782 //---------------------------------------------------------------------------
 783 // Helper functions for fatal error handler
 784 
 785 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
 786   assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
 787 
 788   int cols = 0;
 789   int cols_per_line = 0;
 790   switch (unitsize) {
 791     case 1: cols_per_line = 16; break;
 792     case 2: cols_per_line = 8;  break;
 793     case 4: cols_per_line = 4;  break;
 794     case 8: cols_per_line = 2;  break;
 795     default: return;
 796   }
 797 
 798   address p = start;
 799   st->print(PTR_FORMAT ":   ", start);
 800   while (p < end) {
 801     switch (unitsize) {
 802       case 1: st->print("%02x", *(u1*)p); break;
 803       case 2: st->print("%04x", *(u2*)p); break;
 804       case 4: st->print("%08x", *(u4*)p); break;
 805       case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
 806     }
 807     p += unitsize;
 808     cols++;
 809     if (cols >= cols_per_line && p < end) {
 810        cols = 0;
 811        st->cr();
 812        st->print(PTR_FORMAT ":   ", p);
 813     } else {
 814        st->print(" ");
 815     }
 816   }
 817   st->cr();
 818 }
 819 
 820 void os::print_environment_variables(outputStream* st, const char** env_list,
 821                                      char* buffer, int len) {
 822   if (env_list) {
 823     st->print_cr("Environment Variables:");
 824 
 825     for (int i = 0; env_list[i] != NULL; i++) {
 826       if (getenv(env_list[i], buffer, len)) {
 827         st->print("%s", env_list[i]);
 828         st->print("=");
 829         st->print_cr("%s", buffer);
 830       }
 831     }
 832   }
 833 }
 834 
 835 void os::print_cpu_info(outputStream* st) {
 836   // cpu
 837   st->print("CPU:");
 838   st->print("total %d", os::processor_count());
 839   // It's not safe to query number of active processors after crash
 840   // st->print("(active %d)", os::active_processor_count()); but we can
 841   // print the initial number of active processors.
 842   // We access the raw value here because the assert in the accessor will
 843   // fail if the crash occurs before initialization of this value.
 844   st->print(" (initial active %d)", _initial_active_processor_count);
 845   st->print(" %s", VM_Version::cpu_features());
 846   st->cr();
 847   pd_print_cpu_info(st);
 848 }
 849 
 850 void os::print_date_and_time(outputStream *st, char* buf, size_t buflen) {
 851   const int secs_per_day  = 86400;
 852   const int secs_per_hour = 3600;
 853   const int secs_per_min  = 60;
 854 
 855   time_t tloc;
 856   (void)time(&tloc);
 857   st->print("time: %s", ctime(&tloc));  // ctime adds newline.
 858 
 859   struct tm tz;
 860   if (localtime_pd(&tloc, &tz) != NULL) {
 861     ::strftime(buf, buflen, "%Z", &tz);
 862     st->print_cr("timezone: %s", buf);
 863   }
 864 
 865   double t = os::elapsedTime();
 866   // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
 867   //       Linux. Must be a bug in glibc ? Workaround is to round "t" to int
 868   //       before printf. We lost some precision, but who cares?
 869   int eltime = (int)t;  // elapsed time in seconds
 870 
 871   // print elapsed time in a human-readable format:
 872   int eldays = eltime / secs_per_day;
 873   int day_secs = eldays * secs_per_day;
 874   int elhours = (eltime - day_secs) / secs_per_hour;
 875   int hour_secs = elhours * secs_per_hour;
 876   int elmins = (eltime - day_secs - hour_secs) / secs_per_min;
 877   int minute_secs = elmins * secs_per_min;
 878   int elsecs = (eltime - day_secs - hour_secs - minute_secs);
 879   st->print_cr("elapsed time: %d seconds (%dd %dh %dm %ds)", eltime, eldays, elhours, elmins, elsecs);
 880 }
 881 
 882 // moved from debug.cpp (used to be find()) but still called from there
 883 // The verbose parameter is only set by the debug code in one case
 884 void os::print_location(outputStream* st, intptr_t x, bool verbose) {
 885   address addr = (address)x;
 886   CodeBlob* b = CodeCache::find_blob_unsafe(addr);
 887   if (b != NULL) {
 888     if (b->is_buffer_blob()) {
 889       // the interpreter is generated into a buffer blob
 890       InterpreterCodelet* i = Interpreter::codelet_containing(addr);
 891       if (i != NULL) {
 892         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an Interpreter codelet", addr, (int)(addr - i->code_begin()));
 893         i->print_on(st);
 894         return;
 895       }
 896       if (Interpreter::contains(addr)) {
 897         st->print_cr(INTPTR_FORMAT " is pointing into interpreter code"
 898                      " (not bytecode specific)", addr);
 899         return;
 900       }
 901       //
 902       if (AdapterHandlerLibrary::contains(b)) {
 903         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an AdapterHandler", addr, (int)(addr - b->code_begin()));
 904         AdapterHandlerLibrary::print_handler_on(st, b);
 905       }
 906       // the stubroutines are generated into a buffer blob
 907       StubCodeDesc* d = StubCodeDesc::desc_for(addr);
 908       if (d != NULL) {
 909         st->print_cr(INTPTR_FORMAT " is at begin+%d in a stub", addr, (int)(addr - d->begin()));
 910         d->print_on(st);
 911         st->cr();
 912         return;
 913       }
 914       if (StubRoutines::contains(addr)) {
 915         st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) "
 916                      "stub routine", addr);
 917         return;
 918       }
 919       // the InlineCacheBuffer is using stubs generated into a buffer blob
 920       if (InlineCacheBuffer::contains(addr)) {
 921         st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", addr);
 922         return;
 923       }
 924       VtableStub* v = VtableStubs::stub_containing(addr);
 925       if (v != NULL) {
 926         st->print_cr(INTPTR_FORMAT " is at entry_point+%d in a vtable stub", addr, (int)(addr - v->entry_point()));
 927         v->print_on(st);
 928         st->cr();
 929         return;
 930       }
 931     }
 932     nmethod* nm = b->as_nmethod_or_null();
 933     if (nm != NULL) {
 934       ResourceMark rm;
 935       st->print(INTPTR_FORMAT " is at entry_point+%d in (nmethod*)" INTPTR_FORMAT,
 936                 addr, (int)(addr - nm->entry_point()), nm);
 937       if (verbose) {
 938         st->print(" for ");
 939         nm->method()->print_value_on(st);
 940       }
 941       st->cr();
 942       nm->print_nmethod(verbose);
 943       return;
 944     }
 945     st->print_cr(INTPTR_FORMAT " is at code_begin+%d in ", addr, (int)(addr - b->code_begin()));
 946     b->print_on(st);
 947     return;
 948   }
 949 
 950   if (Universe::heap()->is_in(addr)) {
 951     HeapWord* p = Universe::heap()->block_start(addr);
 952     bool print = false;
 953     // If we couldn't find it it just may mean that heap wasn't parseable
 954     // See if we were just given an oop directly
 955     if (p != NULL && Universe::heap()->block_is_obj(p)) {
 956       print = true;
 957     } else if (p == NULL && ((oopDesc*)addr)->is_oop()) {
 958       p = (HeapWord*) addr;
 959       print = true;
 960     }
 961     if (print) {
 962       if (p == (HeapWord*) addr) {
 963         st->print_cr(INTPTR_FORMAT " is an oop", addr);
 964       } else {
 965         st->print_cr(INTPTR_FORMAT " is pointing into object: " INTPTR_FORMAT, addr, p);
 966       }
 967       oop(p)->print_on(st);
 968       return;
 969     }
 970   } else {
 971     if (Universe::heap()->is_in_reserved(addr)) {
 972       st->print_cr(INTPTR_FORMAT " is an unallocated location "
 973                    "in the heap", addr);
 974       return;
 975     }
 976   }
 977   if (JNIHandles::is_global_handle((jobject) addr)) {
 978     st->print_cr(INTPTR_FORMAT " is a global jni handle", addr);
 979     return;
 980   }
 981   if (JNIHandles::is_weak_global_handle((jobject) addr)) {
 982     st->print_cr(INTPTR_FORMAT " is a weak global jni handle", addr);
 983     return;
 984   }
 985 #ifndef PRODUCT
 986   // we don't keep the block list in product mode
 987   if (JNIHandleBlock::any_contains((jobject) addr)) {
 988     st->print_cr(INTPTR_FORMAT " is a local jni handle", addr);
 989     return;
 990   }
 991 #endif
 992 
 993   for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
 994     // Check for privilege stack
 995     if (thread->privileged_stack_top() != NULL &&
 996         thread->privileged_stack_top()->contains(addr)) {
 997       st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack "
 998                    "for thread: " INTPTR_FORMAT, addr, thread);
 999       if (verbose) thread->print_on(st);
1000       return;
1001     }
1002     // If the addr is a java thread print information about that.
1003     if (addr == (address)thread) {
1004       if (verbose) {
1005         thread->print_on(st);
1006       } else {
1007         st->print_cr(INTPTR_FORMAT " is a thread", addr);
1008       }
1009       return;
1010     }
1011     // If the addr is in the stack region for this thread then report that
1012     // and print thread info
1013     if (thread->stack_base() >= addr &&
1014         addr > (thread->stack_base() - thread->stack_size())) {
1015       st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
1016                    INTPTR_FORMAT, addr, thread);
1017       if (verbose) thread->print_on(st);
1018       return;
1019     }
1020 
1021   }
1022 
1023   // Check if in metaspace and print types that have vptrs (only method now)
1024   if (Metaspace::contains(addr)) {
1025     if (Method::has_method_vptr((const void*)addr)) {
1026       ((Method*)addr)->print_value_on(st);
1027       st->cr();
1028     } else {
1029       // Use addr->print() from the debugger instead (not here)
1030       st->print_cr(INTPTR_FORMAT " is pointing into metadata", addr);
1031     }
1032     return;
1033   }
1034 
1035   // Try an OS specific find
1036   if (os::find(addr, st)) {
1037     return;
1038   }
1039 
1040   st->print_cr(INTPTR_FORMAT " is an unknown value", addr);
1041 }
1042 
1043 // Looks like all platforms except IA64 can use the same function to check
1044 // if C stack is walkable beyond current frame. The check for fp() is not
1045 // necessary on Sparc, but it's harmless.
1046 bool os::is_first_C_frame(frame* fr) {
1047 #if (defined(IA64) && !defined(AIX)) && !defined(_WIN32)
1048   // On IA64 we have to check if the callers bsp is still valid
1049   // (i.e. within the register stack bounds).
1050   // Notice: this only works for threads created by the VM and only if
1051   // we walk the current stack!!! If we want to be able to walk
1052   // arbitrary other threads, we'll have to somehow store the thread
1053   // object in the frame.
1054   Thread *thread = Thread::current();
1055   if ((address)fr->fp() <=
1056       thread->register_stack_base() HPUX_ONLY(+ 0x0) LINUX_ONLY(+ 0x50)) {
1057     // This check is a little hacky, because on Linux the first C
1058     // frame's ('start_thread') register stack frame starts at
1059     // "register_stack_base + 0x48" while on HPUX, the first C frame's
1060     // ('__pthread_bound_body') register stack frame seems to really
1061     // start at "register_stack_base".
1062     return true;
1063   } else {
1064     return false;
1065   }
1066 #elif defined(IA64) && defined(_WIN32)
1067   return true;
1068 #else
1069   // Load up sp, fp, sender sp and sender fp, check for reasonable values.
1070   // Check usp first, because if that's bad the other accessors may fault
1071   // on some architectures.  Ditto ufp second, etc.
1072   uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
1073   // sp on amd can be 32 bit aligned.
1074   uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
1075 
1076   uintptr_t usp    = (uintptr_t)fr->sp();
1077   if ((usp & sp_align_mask) != 0) return true;
1078 
1079   uintptr_t ufp    = (uintptr_t)fr->fp();
1080   if ((ufp & fp_align_mask) != 0) return true;
1081 
1082   uintptr_t old_sp = (uintptr_t)fr->sender_sp();
1083   if ((old_sp & sp_align_mask) != 0) return true;
1084   if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
1085 
1086   uintptr_t old_fp = (uintptr_t)fr->link();
1087   if ((old_fp & fp_align_mask) != 0) return true;
1088   if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
1089 
1090   // stack grows downwards; if old_fp is below current fp or if the stack
1091   // frame is too large, either the stack is corrupted or fp is not saved
1092   // on stack (i.e. on x86, ebp may be used as general register). The stack
1093   // is not walkable beyond current frame.
1094   if (old_fp < ufp) return true;
1095   if (old_fp - ufp > 64 * K) return true;
1096 
1097   return false;
1098 #endif
1099 }
1100 
1101 #ifdef ASSERT
1102 extern "C" void test_random() {
1103   const double m = 2147483647;
1104   double mean = 0.0, variance = 0.0, t;
1105   long reps = 10000;
1106   unsigned long seed = 1;
1107 
1108   tty->print_cr("seed %ld for %ld repeats...", seed, reps);
1109   os::init_random(seed);
1110   long num;
1111   for (int k = 0; k < reps; k++) {
1112     num = os::random();
1113     double u = (double)num / m;
1114     assert(u >= 0.0 && u <= 1.0, "bad random number!");
1115 
1116     // calculate mean and variance of the random sequence
1117     mean += u;
1118     variance += (u*u);
1119   }
1120   mean /= reps;
1121   variance /= (reps - 1);
1122 
1123   assert(num == 1043618065, "bad seed");
1124   tty->print_cr("mean of the 1st 10000 numbers: %f", mean);
1125   tty->print_cr("variance of the 1st 10000 numbers: %f", variance);
1126   const double eps = 0.0001;
1127   t = fabsd(mean - 0.5018);
1128   assert(t < eps, "bad mean");
1129   t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355;
1130   assert(t < eps, "bad variance");
1131 }
1132 #endif
1133 
1134 
1135 // Set up the boot classpath.
1136 
1137 char* os::format_boot_path(const char* format_string,
1138                            const char* home,
1139                            int home_len,
1140                            char fileSep,
1141                            char pathSep) {
1142     assert((fileSep == '/' && pathSep == ':') ||
1143            (fileSep == '\\' && pathSep == ';'), "unexpected seperator chars");
1144 
1145     // Scan the format string to determine the length of the actual
1146     // boot classpath, and handle platform dependencies as well.
1147     int formatted_path_len = 0;
1148     const char* p;
1149     for (p = format_string; *p != 0; ++p) {
1150         if (*p == '%') formatted_path_len += home_len - 1;
1151         ++formatted_path_len;
1152     }
1153 
1154     char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal);
1155     if (formatted_path == NULL) {
1156         return NULL;
1157     }
1158 
1159     // Create boot classpath from format, substituting separator chars and
1160     // java home directory.
1161     char* q = formatted_path;
1162     for (p = format_string; *p != 0; ++p) {
1163         switch (*p) {
1164         case '%':
1165             strcpy(q, home);
1166             q += home_len;
1167             break;
1168         case '/':
1169             *q++ = fileSep;
1170             break;
1171         case ':':
1172             *q++ = pathSep;
1173             break;
1174         default:
1175             *q++ = *p;
1176         }
1177     }
1178     *q = '\0';
1179 
1180     assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
1181     return formatted_path;
1182 }
1183 
1184 
1185 bool os::set_boot_path(char fileSep, char pathSep) {
1186     const char* home = Arguments::get_java_home();
1187     int home_len = (int)strlen(home);
1188 
1189     static const char* meta_index_dir_format = "%/lib/";
1190     static const char* meta_index_format = "%/lib/meta-index";
1191     char* meta_index = format_boot_path(meta_index_format, home, home_len, fileSep, pathSep);
1192     if (meta_index == NULL) return false;
1193     char* meta_index_dir = format_boot_path(meta_index_dir_format, home, home_len, fileSep, pathSep);
1194     if (meta_index_dir == NULL) return false;
1195     Arguments::set_meta_index_path(meta_index, meta_index_dir);
1196 
1197     // Any modification to the JAR-file list, for the boot classpath must be
1198     // aligned with install/install/make/common/Pack.gmk. Note: boot class
1199     // path class JARs, are stripped for StackMapTable to reduce download size.
1200     static const char classpath_format[] =
1201         "%/lib/resources.jar:"
1202         "%/lib/rt.jar:"
1203         "%/lib/sunrsasign.jar:"
1204         "%/lib/jsse.jar:"
1205         "%/lib/jce.jar:"
1206         "%/lib/charsets.jar:"
1207         "%/lib/jfr.jar:"
1208         "%/classes";
1209     char* sysclasspath = format_boot_path(classpath_format, home, home_len, fileSep, pathSep);
1210     if (sysclasspath == NULL) return false;
1211     Arguments::set_sysclasspath(sysclasspath);
1212 
1213     return true;
1214 }
1215 
1216 /*
1217  * Splits a path, based on its separator, the number of
1218  * elements is returned back in n.
1219  * It is the callers responsibility to:
1220  *   a> check the value of n, and n may be 0.
1221  *   b> ignore any empty path elements
1222  *   c> free up the data.
1223  */
1224 char** os::split_path(const char* path, int* n) {
1225   *n = 0;
1226   if (path == NULL || strlen(path) == 0) {
1227     return NULL;
1228   }
1229   const char psepchar = *os::path_separator();
1230   char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal);
1231   if (inpath == NULL) {
1232     return NULL;
1233   }
1234   strcpy(inpath, path);
1235   int count = 1;
1236   char* p = strchr(inpath, psepchar);
1237   // Get a count of elements to allocate memory
1238   while (p != NULL) {
1239     count++;
1240     p++;
1241     p = strchr(p, psepchar);
1242   }
1243   char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count, mtInternal);
1244   if (opath == NULL) {
1245     return NULL;
1246   }
1247 
1248   // do the actual splitting
1249   p = inpath;
1250   for (int i = 0 ; i < count ; i++) {
1251     size_t len = strcspn(p, os::path_separator());
1252     if (len > JVM_MAXPATHLEN) {
1253       return NULL;
1254     }
1255     // allocate the string and add terminator storage
1256     char* s  = (char*)NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
1257     if (s == NULL) {
1258       return NULL;
1259     }
1260     strncpy(s, p, len);
1261     s[len] = '\0';
1262     opath[i] = s;
1263     p += len + 1;
1264   }
1265   FREE_C_HEAP_ARRAY(char, inpath, mtInternal);
1266   *n = count;
1267   return opath;
1268 }
1269 
1270 void os::set_memory_serialize_page(address page) {
1271   int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64);
1272   _mem_serialize_page = (volatile int32_t *)page;
1273   // We initialize the serialization page shift count here
1274   // We assume a cache line size of 64 bytes
1275   assert(SerializePageShiftCount == count,
1276          "thread size changed, fix SerializePageShiftCount constant");
1277   set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t)));
1278 }
1279 
1280 static volatile intptr_t SerializePageLock = 0;
1281 
1282 // This method is called from signal handler when SIGSEGV occurs while the current
1283 // thread tries to store to the "read-only" memory serialize page during state
1284 // transition.
1285 void os::block_on_serialize_page_trap() {
1286   if (TraceSafepoint) {
1287     tty->print_cr("Block until the serialize page permission restored");
1288   }
1289   // When VMThread is holding the SerializePageLock during modifying the
1290   // access permission of the memory serialize page, the following call
1291   // will block until the permission of that page is restored to rw.
1292   // Generally, it is unsafe to manipulate locks in signal handlers, but in
1293   // this case, it's OK as the signal is synchronous and we know precisely when
1294   // it can occur.
1295   Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page");
1296   Thread::muxRelease(&SerializePageLock);
1297 }
1298 
1299 // Serialize all thread state variables
1300 void os::serialize_thread_states() {
1301   // On some platforms such as Solaris & Linux, the time duration of the page
1302   // permission restoration is observed to be much longer than expected  due to
1303   // scheduler starvation problem etc. To avoid the long synchronization
1304   // time and expensive page trap spinning, 'SerializePageLock' is used to block
1305   // the mutator thread if such case is encountered. See bug 6546278 for details.
1306   Thread::muxAcquire(&SerializePageLock, "serialize_thread_states");
1307   os::protect_memory((char *)os::get_memory_serialize_page(),
1308                      os::vm_page_size(), MEM_PROT_READ);
1309   os::protect_memory((char *)os::get_memory_serialize_page(),
1310                      os::vm_page_size(), MEM_PROT_RW);
1311   Thread::muxRelease(&SerializePageLock);
1312 }
1313 
1314 // Returns true if the current stack pointer is above the stack shadow
1315 // pages, false otherwise.
1316 
1317 bool os::stack_shadow_pages_available(Thread *thread, methodHandle method) {
1318   assert(StackRedPages > 0 && StackYellowPages > 0,"Sanity check");
1319   address sp = current_stack_pointer();
1320   // Check if we have StackShadowPages above the yellow zone.  This parameter
1321   // is dependent on the depth of the maximum VM call stack possible from
1322   // the handler for stack overflow.  'instanceof' in the stack overflow
1323   // handler or a println uses at least 8k stack of VM and native code
1324   // respectively.
1325   const int framesize_in_bytes =
1326     Interpreter::size_top_interpreter_activation(method()) * wordSize;
1327   int reserved_area = ((StackShadowPages + StackRedPages + StackYellowPages)
1328                       * vm_page_size()) + framesize_in_bytes;
1329   // The very lower end of the stack
1330   address stack_limit = thread->stack_base() - thread->stack_size();
1331   return (sp > (stack_limit + reserved_area));
1332 }
1333 
1334 size_t os::page_size_for_region(size_t region_size, size_t min_pages, bool must_be_aligned) {
1335   assert(min_pages > 0, "sanity");
1336   if (UseLargePages) {
1337     const size_t max_page_size = region_size / min_pages;
1338 
1339     for (size_t i = 0; _page_sizes[i] != 0; ++i) {
1340       const size_t page_size = _page_sizes[i];
1341       if (page_size <= max_page_size) {
1342         if (!must_be_aligned || is_size_aligned(region_size, page_size)) {
1343           return page_size;
1344         }
1345       }
1346     }
1347   }
1348 
1349   return vm_page_size();
1350 }
1351 
1352 size_t os::page_size_for_region_aligned(size_t region_size, size_t min_pages) {
1353   return page_size_for_region(region_size, min_pages, true);
1354 }
1355 
1356 size_t os::page_size_for_region_unaligned(size_t region_size, size_t min_pages) {
1357   return page_size_for_region(region_size, min_pages, false);
1358 }
1359 
1360 #ifndef PRODUCT
1361 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count)
1362 {
1363   if (TracePageSizes) {
1364     tty->print("%s: ", str);
1365     for (int i = 0; i < count; ++i) {
1366       tty->print(" " SIZE_FORMAT, page_sizes[i]);
1367     }
1368     tty->cr();
1369   }
1370 }
1371 
1372 void os::trace_page_sizes(const char* str, const size_t region_min_size,
1373                           const size_t region_max_size, const size_t page_size,
1374                           const char* base, const size_t size)
1375 {
1376   if (TracePageSizes) {
1377     tty->print_cr("%s:  min=" SIZE_FORMAT " max=" SIZE_FORMAT
1378                   " pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT
1379                   " size=" SIZE_FORMAT,
1380                   str, region_min_size, region_max_size,
1381                   page_size, base, size);
1382   }
1383 }
1384 #endif  // #ifndef PRODUCT
1385 
1386 // This is the working definition of a server class machine:
1387 // >= 2 physical CPU's and >=2GB of memory, with some fuzz
1388 // because the graphics memory (?) sometimes masks physical memory.
1389 // If you want to change the definition of a server class machine
1390 // on some OS or platform, e.g., >=4GB on Windohs platforms,
1391 // then you'll have to parameterize this method based on that state,
1392 // as was done for logical processors here, or replicate and
1393 // specialize this method for each platform.  (Or fix os to have
1394 // some inheritance structure and use subclassing.  Sigh.)
1395 // If you want some platform to always or never behave as a server
1396 // class machine, change the setting of AlwaysActAsServerClassMachine
1397 // and NeverActAsServerClassMachine in globals*.hpp.
1398 bool os::is_server_class_machine() {
1399   // First check for the early returns
1400   if (NeverActAsServerClassMachine) {
1401     return false;
1402   }
1403   if (AlwaysActAsServerClassMachine) {
1404     return true;
1405   }
1406   // Then actually look at the machine
1407   bool         result            = false;
1408   const unsigned int    server_processors = 2;
1409   const julong server_memory     = 2UL * G;
1410   // We seem not to get our full complement of memory.
1411   //     We allow some part (1/8?) of the memory to be "missing",
1412   //     based on the sizes of DIMMs, and maybe graphics cards.
1413   const julong missing_memory   = 256UL * M;
1414 
1415   /* Is this a server class machine? */
1416   if ((os::active_processor_count() >= (int)server_processors) &&
1417       (os::physical_memory() >= (server_memory - missing_memory))) {
1418     const unsigned int logical_processors =
1419       VM_Version::logical_processors_per_package();
1420     if (logical_processors > 1) {
1421       const unsigned int physical_packages =
1422         os::active_processor_count() / logical_processors;
1423       if (physical_packages > server_processors) {
1424         result = true;
1425       }
1426     } else {
1427       result = true;
1428     }
1429   }
1430   return result;
1431 }
1432 
1433 void os::initialize_initial_active_processor_count() {
1434   assert(_initial_active_processor_count == 0, "Initial active processor count already set.");
1435   _initial_active_processor_count = active_processor_count();
1436 }
1437 
1438 void os::SuspendedThreadTask::run() {
1439   assert(Threads_lock->owned_by_self() || (_thread == VMThread::vm_thread()), "must have threads lock to call this");
1440   internal_do_task();
1441   _done = true;
1442 }
1443 
1444 bool os::create_stack_guard_pages(char* addr, size_t bytes) {
1445   return os::pd_create_stack_guard_pages(addr, bytes);
1446 }
1447 
1448 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint) {
1449   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1450   if (result != NULL) {
1451     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1452   }
1453 
1454   return result;
1455 }
1456 
1457 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint,
1458    MEMFLAGS flags) {
1459   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1460   if (result != NULL) {
1461     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1462     MemTracker::record_virtual_memory_type((address)result, flags);
1463   }
1464 
1465   return result;
1466 }
1467 
1468 char* os::attempt_reserve_memory_at(size_t bytes, char* addr) {
1469   char* result = pd_attempt_reserve_memory_at(bytes, addr);
1470   if (result != NULL) {
1471     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1472   }
1473   return result;
1474 }
1475 
1476 void os::split_reserved_memory(char *base, size_t size,
1477                                  size_t split, bool realloc) {
1478   pd_split_reserved_memory(base, size, split, realloc);
1479 }
1480 
1481 bool os::commit_memory(char* addr, size_t bytes, bool executable) {
1482   bool res = pd_commit_memory(addr, bytes, executable);
1483   if (res) {
1484     MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1485   }
1486   return res;
1487 }
1488 
1489 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
1490                               bool executable) {
1491   bool res = os::pd_commit_memory(addr, size, alignment_hint, executable);
1492   if (res) {
1493     MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1494   }
1495   return res;
1496 }
1497 
1498 void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable,
1499                                const char* mesg) {
1500   pd_commit_memory_or_exit(addr, bytes, executable, mesg);
1501   MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1502 }
1503 
1504 void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint,
1505                                bool executable, const char* mesg) {
1506   os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg);
1507   MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1508 }
1509 
1510 bool os::uncommit_memory(char* addr, size_t bytes) {
1511   bool res;
1512   if (MemTracker::tracking_level() > NMT_minimal) {
1513     Tracker tkr = MemTracker::get_virtual_memory_uncommit_tracker();
1514     res = pd_uncommit_memory(addr, bytes);
1515     if (res) {
1516       tkr.record((address)addr, bytes);
1517     }
1518   } else {
1519     res = pd_uncommit_memory(addr, bytes);
1520   }
1521   return res;
1522 }
1523 
1524 bool os::release_memory(char* addr, size_t bytes) {
1525   bool res;
1526   if (MemTracker::tracking_level() > NMT_minimal) {
1527     Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1528     res = pd_release_memory(addr, bytes);
1529     if (res) {
1530       tkr.record((address)addr, bytes);
1531     }
1532   } else {
1533     res = pd_release_memory(addr, bytes);
1534   }
1535   return res;
1536 }
1537 
1538 void os::pretouch_memory(char* start, char* end) {
1539   for (volatile char *p = start; p < end; p += os::vm_page_size()) {
1540     *p = 0;
1541   }
1542 }
1543 
1544 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
1545                            char *addr, size_t bytes, bool read_only,
1546                            bool allow_exec) {
1547   char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec);
1548   if (result != NULL) {
1549     MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1550   }
1551   return result;
1552 }
1553 
1554 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
1555                              char *addr, size_t bytes, bool read_only,
1556                              bool allow_exec) {
1557   return pd_remap_memory(fd, file_name, file_offset, addr, bytes,
1558                     read_only, allow_exec);
1559 }
1560 
1561 bool os::unmap_memory(char *addr, size_t bytes) {
1562   bool result;
1563   if (MemTracker::tracking_level() > NMT_minimal) {
1564     Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1565     result = pd_unmap_memory(addr, bytes);
1566     if (result) {
1567       tkr.record((address)addr, bytes);
1568     }
1569   } else {
1570     result = pd_unmap_memory(addr, bytes);
1571   }
1572   return result;
1573 }
1574 
1575 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
1576   pd_free_memory(addr, bytes, alignment_hint);
1577 }
1578 
1579 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
1580   pd_realign_memory(addr, bytes, alignment_hint);
1581 }
1582 
1583 #ifndef TARGET_OS_FAMILY_windows
1584 /* try to switch state from state "from" to state "to"
1585  * returns the state set after the method is complete
1586  */
1587 os::SuspendResume::State os::SuspendResume::switch_state(os::SuspendResume::State from,
1588                                                          os::SuspendResume::State to)
1589 {
1590   os::SuspendResume::State result =
1591     (os::SuspendResume::State) Atomic::cmpxchg((jint) to, (jint *) &_state, (jint) from);
1592   if (result == from) {
1593     // success
1594     return to;
1595   }
1596   return result;
1597 }
1598 #endif
1599 
1600 /////////////// Unit tests ///////////////
1601 
1602 #ifndef PRODUCT
1603 
1604 #define assert_eq(a,b) assert(a == b, err_msg(SIZE_FORMAT " != " SIZE_FORMAT, a, b))
1605 
1606 class TestOS : AllStatic {
1607   static size_t small_page_size() {
1608     return os::vm_page_size();
1609   }
1610 
1611   static size_t large_page_size() {
1612     const size_t large_page_size_example = 4 * M;
1613     return os::page_size_for_region_aligned(large_page_size_example, 1);
1614   }
1615 
1616   static void test_page_size_for_region_aligned() {
1617     if (UseLargePages) {
1618       const size_t small_page = small_page_size();
1619       const size_t large_page = large_page_size();
1620 
1621       if (large_page > small_page) {
1622         size_t num_small_pages_in_large = large_page / small_page;
1623         size_t page = os::page_size_for_region_aligned(large_page, num_small_pages_in_large);
1624 
1625         assert_eq(page, small_page);
1626       }
1627     }
1628   }
1629 
1630   static void test_page_size_for_region_alignment() {
1631     if (UseLargePages) {
1632       const size_t small_page = small_page_size();
1633       const size_t large_page = large_page_size();
1634       if (large_page > small_page) {
1635         const size_t unaligned_region = large_page + 17;
1636         size_t page = os::page_size_for_region_aligned(unaligned_region, 1);
1637         assert_eq(page, small_page);
1638 
1639         const size_t num_pages = 5;
1640         const size_t aligned_region = large_page * num_pages;
1641         page = os::page_size_for_region_aligned(aligned_region, num_pages);
1642         assert_eq(page, large_page);
1643       }
1644     }
1645   }
1646 
1647   static void test_page_size_for_region_unaligned() {
1648     if (UseLargePages) {
1649       // Given exact page size, should return that page size.
1650       for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
1651         size_t expected = os::_page_sizes[i];
1652         size_t actual = os::page_size_for_region_unaligned(expected, 1);
1653         assert_eq(expected, actual);
1654       }
1655 
1656       // Given slightly larger size than a page size, return the page size.
1657       for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
1658         size_t expected = os::_page_sizes[i];
1659         size_t actual = os::page_size_for_region_unaligned(expected + 17, 1);
1660         assert_eq(expected, actual);
1661       }
1662 
1663       // Given a slightly smaller size than a page size,
1664       // return the next smaller page size.
1665       if (os::_page_sizes[1] > os::_page_sizes[0]) {
1666         size_t expected = os::_page_sizes[0];
1667         size_t actual = os::page_size_for_region_unaligned(os::_page_sizes[1] - 17, 1);
1668         assert_eq(actual, expected);
1669       }
1670 
1671       // Return small page size for values less than a small page.
1672       size_t small_page = small_page_size();
1673       size_t actual = os::page_size_for_region_unaligned(small_page - 17, 1);
1674       assert_eq(small_page, actual);
1675     }
1676   }
1677 
1678  public:
1679   static void run_tests() {
1680     test_page_size_for_region_aligned();
1681     test_page_size_for_region_alignment();
1682     test_page_size_for_region_unaligned();
1683   }
1684 };
1685 
1686 void TestOS_test() {
1687   TestOS::run_tests();
1688 }
1689 
1690 #endif // PRODUCT