1 /*
   2  * Copyright (c) 1997, 2013, 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 #include "oops/oop.inline.hpp"
  36 #include "prims/jvm.h"
  37 #include "prims/jvm_misc.hpp"
  38 #include "prims/privilegedStack.hpp"
  39 #include "runtime/arguments.hpp"
  40 #include "runtime/frame.inline.hpp"
  41 #include "runtime/interfaceSupport.hpp"
  42 #include "runtime/java.hpp"
  43 #include "runtime/javaCalls.hpp"
  44 #include "runtime/mutexLocker.hpp"
  45 #include "runtime/os.hpp"
  46 #include "runtime/stubRoutines.hpp"
  47 #include "runtime/thread.inline.hpp"
  48 #include "services/attachListener.hpp"
  49 #include "services/memTracker.hpp"
  50 #include "services/threadService.hpp"
  51 #include "utilities/defaultStream.hpp"
  52 #include "utilities/events.hpp"
  53 #ifdef TARGET_OS_FAMILY_linux
  54 # include "os_linux.inline.hpp"
  55 #endif
  56 #ifdef TARGET_OS_FAMILY_solaris
  57 # include "os_solaris.inline.hpp"
  58 #endif
  59 #ifdef TARGET_OS_FAMILY_windows
  60 # include "os_windows.inline.hpp"
  61 #endif
  62 #ifdef TARGET_OS_FAMILY_bsd
  63 # include "os_bsd.inline.hpp"
  64 #endif
  65 
  66 # include <signal.h>
  67 
  68 OSThread*         os::_starting_thread    = NULL;
  69 address           os::_polling_page       = NULL;
  70 volatile int32_t* os::_mem_serialize_page = NULL;
  71 uintptr_t         os::_serialize_page_mask = 0;
  72 long              os::_rand_seed          = 1;
  73 int               os::_processor_count    = 0;
  74 size_t            os::_page_sizes[os::page_sizes_max];
  75 
  76 #ifndef PRODUCT
  77 julong os::num_mallocs = 0;         // # of calls to malloc/realloc
  78 julong os::alloc_bytes = 0;         // # of bytes allocated
  79 julong os::num_frees = 0;           // # of calls to free
  80 julong os::free_bytes = 0;          // # of bytes freed
  81 #endif
  82 
  83 static juint cur_malloc_words = 0;  // current size for MallocMaxTestWords
  84 
  85 void os_init_globals() {
  86   // Called from init_globals().
  87   // See Threads::create_vm() in thread.cpp, and init.cpp.
  88   os::init_globals();
  89 }
  90 
  91 // Fill in buffer with current local time as an ISO-8601 string.
  92 // E.g., yyyy-mm-ddThh:mm:ss-zzzz.
  93 // Returns buffer, or NULL if it failed.
  94 // This would mostly be a call to
  95 //     strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
  96 // except that on Windows the %z behaves badly, so we do it ourselves.
  97 // Also, people wanted milliseconds on there,
  98 // and strftime doesn't do milliseconds.
  99 char* os::iso8601_time(char* buffer, size_t buffer_length) {
 100   // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
 101   //                                      1         2
 102   //                             12345678901234567890123456789
 103   static const char* iso8601_format =
 104     "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d";
 105   static const size_t needed_buffer = 29;
 106 
 107   // Sanity check the arguments
 108   if (buffer == NULL) {
 109     assert(false, "NULL buffer");
 110     return NULL;
 111   }
 112   if (buffer_length < needed_buffer) {
 113     assert(false, "buffer_length too small");
 114     return NULL;
 115   }
 116   // Get the current time
 117   jlong milliseconds_since_19700101 = javaTimeMillis();
 118   const int milliseconds_per_microsecond = 1000;
 119   const time_t seconds_since_19700101 =
 120     milliseconds_since_19700101 / milliseconds_per_microsecond;
 121   const int milliseconds_after_second =
 122     milliseconds_since_19700101 % milliseconds_per_microsecond;
 123   // Convert the time value to a tm and timezone variable
 124   struct tm time_struct;
 125   if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
 126     assert(false, "Failed localtime_pd");
 127     return NULL;
 128   }
 129 #if defined(_ALLBSD_SOURCE)
 130   const time_t zone = (time_t) time_struct.tm_gmtoff;
 131 #else
 132   const time_t zone = timezone;
 133 #endif
 134 
 135   // If daylight savings time is in effect,
 136   // we are 1 hour East of our time zone
 137   const time_t seconds_per_minute = 60;
 138   const time_t minutes_per_hour = 60;
 139   const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
 140   time_t UTC_to_local = zone;
 141   if (time_struct.tm_isdst > 0) {
 142     UTC_to_local = UTC_to_local - seconds_per_hour;
 143   }
 144   // Compute the time zone offset.
 145   //    localtime_pd() sets timezone to the difference (in seconds)
 146   //    between UTC and and local time.
 147   //    ISO 8601 says we need the difference between local time and UTC,
 148   //    we change the sign of the localtime_pd() result.
 149   const time_t local_to_UTC = -(UTC_to_local);
 150   // Then we have to figure out if if we are ahead (+) or behind (-) UTC.
 151   char sign_local_to_UTC = '+';
 152   time_t abs_local_to_UTC = local_to_UTC;
 153   if (local_to_UTC < 0) {
 154     sign_local_to_UTC = '-';
 155     abs_local_to_UTC = -(abs_local_to_UTC);
 156   }
 157   // Convert time zone offset seconds to hours and minutes.
 158   const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
 159   const time_t zone_min =
 160     ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
 161 
 162   // Print an ISO 8601 date and time stamp into the buffer
 163   const int year = 1900 + time_struct.tm_year;
 164   const int month = 1 + time_struct.tm_mon;
 165   const int printed = jio_snprintf(buffer, buffer_length, iso8601_format,
 166                                    year,
 167                                    month,
 168                                    time_struct.tm_mday,
 169                                    time_struct.tm_hour,
 170                                    time_struct.tm_min,
 171                                    time_struct.tm_sec,
 172                                    milliseconds_after_second,
 173                                    sign_local_to_UTC,
 174                                    zone_hours,
 175                                    zone_min);
 176   if (printed == 0) {
 177     assert(false, "Failed jio_printf");
 178     return NULL;
 179   }
 180   return buffer;
 181 }
 182 
 183 OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
 184 #ifdef ASSERT
 185   if (!(!thread->is_Java_thread() ||
 186          Thread::current() == thread  ||
 187          Threads_lock->owned_by_self()
 188          || thread->is_Compiler_thread()
 189         )) {
 190     assert(false, "possibility of dangling Thread pointer");
 191   }
 192 #endif
 193 
 194   if (p >= MinPriority && p <= MaxPriority) {
 195     int priority = java_to_os_priority[p];
 196     return set_native_priority(thread, priority);
 197   } else {
 198     assert(false, "Should not happen");
 199     return OS_ERR;
 200   }
 201 }
 202 
 203 // The mapping from OS priority back to Java priority may be inexact because
 204 // Java priorities can map M:1 with native priorities. If you want the definite
 205 // Java priority then use JavaThread::java_priority()
 206 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
 207   int p;
 208   int os_prio;
 209   OSReturn ret = get_native_priority(thread, &os_prio);
 210   if (ret != OS_OK) return ret;
 211 
 212   if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) {
 213     for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
 214   } else {
 215     // niceness values are in reverse order
 216     for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] < os_prio; p--) ;
 217   }
 218   priority = (ThreadPriority)p;
 219   return OS_OK;
 220 }
 221 
 222 
 223 // --------------------- sun.misc.Signal (optional) ---------------------
 224 
 225 
 226 // SIGBREAK is sent by the keyboard to query the VM state
 227 #ifndef SIGBREAK
 228 #define SIGBREAK SIGQUIT
 229 #endif
 230 
 231 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
 232 
 233 
 234 static void signal_thread_entry(JavaThread* thread, TRAPS) {
 235   os::set_priority(thread, NearMaxPriority);
 236   while (true) {
 237     int sig;
 238     {
 239       // FIXME : Currently we have not decieded what should be the status
 240       //         for this java thread blocked here. Once we decide about
 241       //         that we should fix this.
 242       sig = os::signal_wait();
 243     }
 244     if (sig == os::sigexitnum_pd()) {
 245        // Terminate the signal thread
 246        return;
 247     }
 248 
 249     switch (sig) {
 250       case SIGBREAK: {
 251         // Check if the signal is a trigger to start the Attach Listener - in that
 252         // case don't print stack traces.
 253         if (!DisableAttachMechanism && AttachListener::is_init_trigger()) {
 254           continue;
 255         }
 256         // Print stack traces
 257         // Any SIGBREAK operations added here should make sure to flush
 258         // the output stream (e.g. tty->flush()) after output.  See 4803766.
 259         // Each module also prints an extra carriage return after its output.
 260         VM_PrintThreads op;
 261         VMThread::execute(&op);
 262         VM_PrintJNI jni_op;
 263         VMThread::execute(&jni_op);
 264         VM_FindDeadlocks op1(tty);
 265         VMThread::execute(&op1);
 266         Universe::print_heap_at_SIGBREAK();
 267         if (PrintClassHistogram) {
 268           VM_GC_HeapInspection op1(gclog_or_tty, true /* force full GC before heap inspection */);
 269           VMThread::execute(&op1);
 270         }
 271         if (JvmtiExport::should_post_data_dump()) {
 272           JvmtiExport::post_data_dump();
 273         }
 274         break;
 275       }
 276       default: {
 277         // Dispatch the signal to java
 278         HandleMark hm(THREAD);
 279         Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_Signal(), THREAD);
 280         KlassHandle klass (THREAD, k);
 281         if (klass.not_null()) {
 282           JavaValue result(T_VOID);
 283           JavaCallArguments args;
 284           args.push_int(sig);
 285           JavaCalls::call_static(
 286             &result,
 287             klass,
 288             vmSymbols::dispatch_name(),
 289             vmSymbols::int_void_signature(),
 290             &args,
 291             THREAD
 292           );
 293         }
 294         if (HAS_PENDING_EXCEPTION) {
 295           // tty is initialized early so we don't expect it to be null, but
 296           // if it is we can't risk doing an initialization that might
 297           // trigger additional out-of-memory conditions
 298           if (tty != NULL) {
 299             char klass_name[256];
 300             char tmp_sig_name[16];
 301             const char* sig_name = "UNKNOWN";
 302             InstanceKlass::cast(PENDING_EXCEPTION->klass())->
 303               name()->as_klass_external_name(klass_name, 256);
 304             if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
 305               sig_name = tmp_sig_name;
 306             warning("Exception %s occurred dispatching signal %s to handler"
 307                     "- the VM may need to be forcibly terminated",
 308                     klass_name, sig_name );
 309           }
 310           CLEAR_PENDING_EXCEPTION;
 311         }
 312       }
 313     }
 314   }
 315 }
 316 
 317 void os::init_ergo() {
 318   // We need to initialize large page support here because ergonomics takes some
 319   // decisions depending on large page support and the calculated large page size.
 320   large_page_init();
 321 }
 322 
 323 void os::signal_init() {
 324   if (!ReduceSignalUsage) {
 325     // Setup JavaThread for processing signals
 326     EXCEPTION_MARK;
 327     Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
 328     instanceKlassHandle klass (THREAD, k);
 329     instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
 330 
 331     const char thread_name[] = "Signal Dispatcher";
 332     Handle string = java_lang_String::create_from_str(thread_name, CHECK);
 333 
 334     // Initialize thread_oop to put it into the system threadGroup
 335     Handle thread_group (THREAD, Universe::system_thread_group());
 336     JavaValue result(T_VOID);
 337     JavaCalls::call_special(&result, thread_oop,
 338                            klass,
 339                            vmSymbols::object_initializer_name(),
 340                            vmSymbols::threadgroup_string_void_signature(),
 341                            thread_group,
 342                            string,
 343                            CHECK);
 344 
 345     KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
 346     JavaCalls::call_special(&result,
 347                             thread_group,
 348                             group,
 349                             vmSymbols::add_method_name(),
 350                             vmSymbols::thread_void_signature(),
 351                             thread_oop,         // ARG 1
 352                             CHECK);
 353 
 354     os::signal_init_pd();
 355 
 356     { MutexLocker mu(Threads_lock);
 357       JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
 358 
 359       // At this point it may be possible that no osthread was created for the
 360       // JavaThread due to lack of memory. We would have to throw an exception
 361       // in that case. However, since this must work and we do not allow
 362       // exceptions anyway, check and abort if this fails.
 363       if (signal_thread == NULL || signal_thread->osthread() == NULL) {
 364         vm_exit_during_initialization("java.lang.OutOfMemoryError",
 365                                       "unable to create new native thread");
 366       }
 367 
 368       java_lang_Thread::set_thread(thread_oop(), signal_thread);
 369       java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
 370       java_lang_Thread::set_daemon(thread_oop());
 371 
 372       signal_thread->set_threadObj(thread_oop());
 373       Threads::add(signal_thread);
 374       Thread::start(signal_thread);
 375     }
 376     // Handle ^BREAK
 377     os::signal(SIGBREAK, os::user_handler());
 378   }
 379 }
 380 
 381 
 382 void os::terminate_signal_thread() {
 383   if (!ReduceSignalUsage)
 384     signal_notify(sigexitnum_pd());
 385 }
 386 
 387 
 388 // --------------------- loading libraries ---------------------
 389 
 390 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
 391 extern struct JavaVM_ main_vm;
 392 
 393 static void* _native_java_library = NULL;
 394 
 395 void* os::native_java_library() {
 396   if (_native_java_library == NULL) {
 397     char buffer[JVM_MAXPATHLEN];
 398     char ebuf[1024];
 399 
 400     // Try to load verify dll first. In 1.3 java dll depends on it and is not
 401     // always able to find it when the loading executable is outside the JDK.
 402     // In order to keep working with 1.2 we ignore any loading errors.
 403     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 404                        "verify")) {
 405       dll_load(buffer, ebuf, sizeof(ebuf));
 406     }
 407 
 408     // Load java dll
 409     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 410                        "java")) {
 411       _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
 412     }
 413     if (_native_java_library == NULL) {
 414       vm_exit_during_initialization("Unable to load native library", ebuf);
 415     }
 416 
 417 #if defined(__OpenBSD__)
 418     // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so
 419     // ignore errors
 420     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 421                        "net")) {
 422       dll_load(buffer, ebuf, sizeof(ebuf));
 423     }
 424 #endif
 425   }
 426   static jboolean onLoaded = JNI_FALSE;
 427   if (onLoaded) {
 428     // We may have to wait to fire OnLoad until TLS is initialized.
 429     if (ThreadLocalStorage::is_initialized()) {
 430       // The JNI_OnLoad handling is normally done by method load in
 431       // java.lang.ClassLoader$NativeLibrary, but the VM loads the base library
 432       // explicitly so we have to check for JNI_OnLoad as well
 433       const char *onLoadSymbols[] = JNI_ONLOAD_SYMBOLS;
 434       JNI_OnLoad_t JNI_OnLoad = CAST_TO_FN_PTR(
 435           JNI_OnLoad_t, dll_lookup(_native_java_library, onLoadSymbols[0]));
 436       if (JNI_OnLoad != NULL) {
 437         JavaThread* thread = JavaThread::current();
 438         ThreadToNativeFromVM ttn(thread);
 439         HandleMark hm(thread);
 440         jint ver = (*JNI_OnLoad)(&main_vm, NULL);
 441         onLoaded = JNI_TRUE;
 442         if (!Threads::is_supported_jni_version_including_1_1(ver)) {
 443           vm_exit_during_initialization("Unsupported JNI version");
 444         }
 445       }
 446     }
 447   }
 448   return _native_java_library;
 449 }
 450 
 451 // --------------------- heap allocation utilities ---------------------
 452 
 453 char *os::strdup(const char *str, MEMFLAGS flags) {
 454   size_t size = strlen(str);
 455   char *dup_str = (char *)malloc(size + 1, flags);
 456   if (dup_str == NULL) return NULL;
 457   strcpy(dup_str, str);
 458   return dup_str;
 459 }
 460 
 461 
 462 
 463 #ifdef ASSERT
 464 #define space_before             (MallocCushion + sizeof(double))
 465 #define space_after              MallocCushion
 466 #define size_addr_from_base(p)   (size_t*)(p + space_before - sizeof(size_t))
 467 #define size_addr_from_obj(p)    ((size_t*)p - 1)
 468 // MallocCushion: size of extra cushion allocated around objects with +UseMallocOnly
 469 // NB: cannot be debug variable, because these aren't set from the command line until
 470 // *after* the first few allocs already happened
 471 #define MallocCushion            16
 472 #else
 473 #define space_before             0
 474 #define space_after              0
 475 #define size_addr_from_base(p)   should not use w/o ASSERT
 476 #define size_addr_from_obj(p)    should not use w/o ASSERT
 477 #define MallocCushion            0
 478 #endif
 479 #define paranoid                 0  /* only set to 1 if you suspect checking code has bug */
 480 
 481 #ifdef ASSERT
 482 inline size_t get_size(void* obj) {
 483   size_t size = *size_addr_from_obj(obj);
 484   if (size < 0) {
 485     fatal(err_msg("free: size field of object #" PTR_FORMAT " was overwritten ("
 486                   SIZE_FORMAT ")", obj, size));
 487   }
 488   return size;
 489 }
 490 
 491 u_char* find_cushion_backwards(u_char* start) {
 492   u_char* p = start;
 493   while (p[ 0] != badResourceValue || p[-1] != badResourceValue ||
 494          p[-2] != badResourceValue || p[-3] != badResourceValue) p--;
 495   // ok, we have four consecutive marker bytes; find start
 496   u_char* q = p - 4;
 497   while (*q == badResourceValue) q--;
 498   return q + 1;
 499 }
 500 
 501 u_char* find_cushion_forwards(u_char* start) {
 502   u_char* p = start;
 503   while (p[0] != badResourceValue || p[1] != badResourceValue ||
 504          p[2] != badResourceValue || p[3] != badResourceValue) p++;
 505   // ok, we have four consecutive marker bytes; find end of cushion
 506   u_char* q = p + 4;
 507   while (*q == badResourceValue) q++;
 508   return q - MallocCushion;
 509 }
 510 
 511 void print_neighbor_blocks(void* ptr) {
 512   // find block allocated before ptr (not entirely crash-proof)
 513   if (MallocCushion < 4) {
 514     tty->print_cr("### cannot find previous block (MallocCushion < 4)");
 515     return;
 516   }
 517   u_char* start_of_this_block = (u_char*)ptr - space_before;
 518   u_char* end_of_prev_block_data = start_of_this_block - space_after -1;
 519   // look for cushion in front of prev. block
 520   u_char* start_of_prev_block = find_cushion_backwards(end_of_prev_block_data);
 521   ptrdiff_t size = *size_addr_from_base(start_of_prev_block);
 522   u_char* obj = start_of_prev_block + space_before;
 523   if (size <= 0 ) {
 524     // start is bad; mayhave been confused by OS data inbetween objects
 525     // search one more backwards
 526     start_of_prev_block = find_cushion_backwards(start_of_prev_block);
 527     size = *size_addr_from_base(start_of_prev_block);
 528     obj = start_of_prev_block + space_before;
 529   }
 530 
 531   if (start_of_prev_block + space_before + size + space_after == start_of_this_block) {
 532     tty->print_cr("### previous object: " PTR_FORMAT " (" SSIZE_FORMAT " bytes)", obj, size);
 533   } else {
 534     tty->print_cr("### previous object (not sure if correct): " PTR_FORMAT " (" SSIZE_FORMAT " bytes)", obj, size);
 535   }
 536 
 537   // now find successor block
 538   u_char* start_of_next_block = (u_char*)ptr + *size_addr_from_obj(ptr) + space_after;
 539   start_of_next_block = find_cushion_forwards(start_of_next_block);
 540   u_char* next_obj = start_of_next_block + space_before;
 541   ptrdiff_t next_size = *size_addr_from_base(start_of_next_block);
 542   if (start_of_next_block[0] == badResourceValue &&
 543       start_of_next_block[1] == badResourceValue &&
 544       start_of_next_block[2] == badResourceValue &&
 545       start_of_next_block[3] == badResourceValue) {
 546     tty->print_cr("### next object: " PTR_FORMAT " (" SSIZE_FORMAT " bytes)", next_obj, next_size);
 547   } else {
 548     tty->print_cr("### next object (not sure if correct): " PTR_FORMAT " (" SSIZE_FORMAT " bytes)", next_obj, next_size);
 549   }
 550 }
 551 
 552 
 553 void report_heap_error(void* memblock, void* bad, const char* where) {
 554   tty->print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees);
 555   tty->print_cr("## memory stomp: byte at " PTR_FORMAT " %s object " PTR_FORMAT, bad, where, memblock);
 556   print_neighbor_blocks(memblock);
 557   fatal("memory stomping error");
 558 }
 559 
 560 void verify_block(void* memblock) {
 561   size_t size = get_size(memblock);
 562   if (MallocCushion) {
 563     u_char* ptr = (u_char*)memblock - space_before;
 564     for (int i = 0; i < MallocCushion; i++) {
 565       if (ptr[i] != badResourceValue) {
 566         report_heap_error(memblock, ptr+i, "in front of");
 567       }
 568     }
 569     u_char* end = (u_char*)memblock + size + space_after;
 570     for (int j = -MallocCushion; j < 0; j++) {
 571       if (end[j] != badResourceValue) {
 572         report_heap_error(memblock, end+j, "after");
 573       }
 574     }
 575   }
 576 }
 577 #endif
 578 
 579 //
 580 // This function supports testing of the malloc out of memory
 581 // condition without really running the system out of memory.
 582 //
 583 static u_char* testMalloc(size_t alloc_size) {
 584   assert(MallocMaxTestWords > 0, "sanity check");
 585 
 586   if ((cur_malloc_words + (alloc_size / BytesPerWord)) > MallocMaxTestWords) {
 587     return NULL;
 588   }
 589 
 590   u_char* ptr = (u_char*)::malloc(alloc_size);
 591 
 592   if (ptr != NULL) {
 593     Atomic::add(((jint) (alloc_size / BytesPerWord)),
 594                 (volatile jint *) &cur_malloc_words);
 595   }
 596   return ptr;
 597 }
 598 
 599 void* os::malloc(size_t size, MEMFLAGS memflags, address caller) {
 600   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 601   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 602 
 603 #ifdef ASSERT
 604   // checking for the WatcherThread and crash_protection first
 605   // since os::malloc can be called when the libjvm.{dll,so} is
 606   // first loaded and we don't have a thread yet.
 607   // try to find the thread after we see that the watcher thread
 608   // exists and has crash protection.
 609   WatcherThread *wt = WatcherThread::watcher_thread();
 610   if (wt != NULL && wt->has_crash_protection()) {
 611     Thread* thread = ThreadLocalStorage::get_thread_slow();
 612     if (thread == wt) {
 613       assert(!wt->has_crash_protection(),
 614           "Can't malloc with crash protection from WatcherThread");
 615     }
 616   }
 617 #endif
 618 
 619   if (size == 0) {
 620     // return a valid pointer if size is zero
 621     // if NULL is returned the calling functions assume out of memory.
 622     size = 1;
 623   }
 624 
 625   const size_t alloc_size = size + space_before + space_after;
 626 
 627   if (size > alloc_size) { // Check for rollover.
 628     return NULL;
 629   }
 630 
 631   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 632 
 633   u_char* ptr;
 634 
 635   if (MallocMaxTestWords > 0) {
 636     ptr = testMalloc(alloc_size);
 637   } else {
 638     ptr = (u_char*)::malloc(alloc_size);
 639   }
 640 
 641 #ifdef ASSERT
 642   if (ptr == NULL) return NULL;
 643   if (MallocCushion) {
 644     for (u_char* p = ptr; p < ptr + MallocCushion; p++) *p = (u_char)badResourceValue;
 645     u_char* end = ptr + space_before + size;
 646     for (u_char* pq = ptr+MallocCushion; pq < end; pq++) *pq = (u_char)uninitBlockPad;
 647     for (u_char* q = end; q < end + MallocCushion; q++) *q = (u_char)badResourceValue;
 648   }
 649   // put size just before data
 650   *size_addr_from_base(ptr) = size;
 651 #endif
 652   u_char* memblock = ptr + space_before;
 653   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 654     tty->print_cr("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, memblock);
 655     breakpoint();
 656   }
 657   debug_only(if (paranoid) verify_block(memblock));
 658   if (PrintMalloc && tty != NULL) tty->print_cr("os::malloc " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, memblock);
 659 
 660   // we do not track MallocCushion memory
 661     MemTracker::record_malloc((address)memblock, size, memflags, caller == 0 ? CALLER_PC : caller);
 662 
 663   return memblock;
 664 }
 665 
 666 
 667 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, address caller) {
 668 #ifndef ASSERT
 669   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 670   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 671   MemTracker::Tracker tkr = MemTracker::get_realloc_tracker();
 672   void* ptr = ::realloc(memblock, size);
 673   if (ptr != NULL) {
 674     tkr.record((address)memblock, (address)ptr, size, memflags,
 675      caller == 0 ? CALLER_PC : caller);
 676   } else {
 677     tkr.discard();
 678   }
 679   return ptr;
 680 #else
 681   if (memblock == NULL) {
 682     return malloc(size, memflags, (caller == 0 ? CALLER_PC : caller));
 683   }
 684   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 685     tty->print_cr("os::realloc caught " PTR_FORMAT, memblock);
 686     breakpoint();
 687   }
 688   verify_block(memblock);
 689   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 690   if (size == 0) return NULL;
 691   // always move the block
 692   void* ptr = malloc(size, memflags, caller == 0 ? CALLER_PC : caller);
 693   if (PrintMalloc) tty->print_cr("os::remalloc " SIZE_FORMAT " bytes, " PTR_FORMAT " --> " PTR_FORMAT, size, memblock, ptr);
 694   // Copy to new memory if malloc didn't fail
 695   if ( ptr != NULL ) {
 696     memcpy(ptr, memblock, MIN2(size, get_size(memblock)));
 697     if (paranoid) verify_block(ptr);
 698     if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
 699       tty->print_cr("os::realloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, ptr);
 700       breakpoint();
 701     }
 702     free(memblock);
 703   }
 704   return ptr;
 705 #endif
 706 }
 707 
 708 
 709 void  os::free(void *memblock, MEMFLAGS memflags) {
 710   NOT_PRODUCT(inc_stat_counter(&num_frees, 1));
 711 #ifdef ASSERT
 712   if (memblock == NULL) return;
 713   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 714     if (tty != NULL) tty->print_cr("os::free caught " PTR_FORMAT, memblock);
 715     breakpoint();
 716   }
 717   verify_block(memblock);
 718   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 719   // Added by detlefs.
 720   if (MallocCushion) {
 721     u_char* ptr = (u_char*)memblock - space_before;
 722     for (u_char* p = ptr; p < ptr + MallocCushion; p++) {
 723       guarantee(*p == badResourceValue,
 724                 "Thing freed should be malloc result.");
 725       *p = (u_char)freeBlockPad;
 726     }
 727     size_t size = get_size(memblock);
 728     inc_stat_counter(&free_bytes, size);
 729     u_char* end = ptr + space_before + size;
 730     for (u_char* q = end; q < end + MallocCushion; q++) {
 731       guarantee(*q == badResourceValue,
 732                 "Thing freed should be malloc result.");
 733       *q = (u_char)freeBlockPad;
 734     }
 735     if (PrintMalloc && tty != NULL)
 736       fprintf(stderr, "os::free " SIZE_FORMAT " bytes --> " PTR_FORMAT "\n", size, (uintptr_t)memblock);
 737   } else if (PrintMalloc && tty != NULL) {
 738     // tty->print_cr("os::free %p", memblock);
 739     fprintf(stderr, "os::free " PTR_FORMAT "\n", (uintptr_t)memblock);
 740   }
 741 #endif
 742   MemTracker::record_free((address)memblock, memflags);
 743 
 744   ::free((char*)memblock - space_before);
 745 }
 746 
 747 void os::init_random(long initval) {
 748   _rand_seed = initval;
 749 }
 750 
 751 
 752 long os::random() {
 753   /* standard, well-known linear congruential random generator with
 754    * next_rand = (16807*seed) mod (2**31-1)
 755    * see
 756    * (1) "Random Number Generators: Good Ones Are Hard to Find",
 757    *      S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
 758    * (2) "Two Fast Implementations of the 'Minimal Standard' Random
 759    *     Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
 760   */
 761   const long a = 16807;
 762   const unsigned long m = 2147483647;
 763   const long q = m / a;        assert(q == 127773, "weird math");
 764   const long r = m % a;        assert(r == 2836, "weird math");
 765 
 766   // compute az=2^31p+q
 767   unsigned long lo = a * (long)(_rand_seed & 0xFFFF);
 768   unsigned long hi = a * (long)((unsigned long)_rand_seed >> 16);
 769   lo += (hi & 0x7FFF) << 16;
 770 
 771   // if q overflowed, ignore the overflow and increment q
 772   if (lo > m) {
 773     lo &= m;
 774     ++lo;
 775   }
 776   lo += hi >> 15;
 777 
 778   // if (p+q) overflowed, ignore the overflow and increment (p+q)
 779   if (lo > m) {
 780     lo &= m;
 781     ++lo;
 782   }
 783   return (_rand_seed = lo);
 784 }
 785 
 786 // The INITIALIZED state is distinguished from the SUSPENDED state because the
 787 // conditions in which a thread is first started are different from those in which
 788 // a suspension is resumed.  These differences make it hard for us to apply the
 789 // tougher checks when starting threads that we want to do when resuming them.
 790 // However, when start_thread is called as a result of Thread.start, on a Java
 791 // thread, the operation is synchronized on the Java Thread object.  So there
 792 // cannot be a race to start the thread and hence for the thread to exit while
 793 // we are working on it.  Non-Java threads that start Java threads either have
 794 // to do so in a context in which races are impossible, or should do appropriate
 795 // locking.
 796 
 797 void os::start_thread(Thread* thread) {
 798   // guard suspend/resume
 799   MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
 800   OSThread* osthread = thread->osthread();
 801   osthread->set_state(RUNNABLE);
 802   pd_start_thread(thread);
 803 }
 804 
 805 //---------------------------------------------------------------------------
 806 // Helper functions for fatal error handler
 807 
 808 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
 809   assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
 810 
 811   int cols = 0;
 812   int cols_per_line = 0;
 813   switch (unitsize) {
 814     case 1: cols_per_line = 16; break;
 815     case 2: cols_per_line = 8;  break;
 816     case 4: cols_per_line = 4;  break;
 817     case 8: cols_per_line = 2;  break;
 818     default: return;
 819   }
 820 
 821   address p = start;
 822   st->print(PTR_FORMAT ":   ", start);
 823   while (p < end) {
 824     switch (unitsize) {
 825       case 1: st->print("%02x", *(u1*)p); break;
 826       case 2: st->print("%04x", *(u2*)p); break;
 827       case 4: st->print("%08x", *(u4*)p); break;
 828       case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
 829     }
 830     p += unitsize;
 831     cols++;
 832     if (cols >= cols_per_line && p < end) {
 833        cols = 0;
 834        st->cr();
 835        st->print(PTR_FORMAT ":   ", p);
 836     } else {
 837        st->print(" ");
 838     }
 839   }
 840   st->cr();
 841 }
 842 
 843 void os::print_environment_variables(outputStream* st, const char** env_list,
 844                                      char* buffer, int len) {
 845   if (env_list) {
 846     st->print_cr("Environment Variables:");
 847 
 848     for (int i = 0; env_list[i] != NULL; i++) {
 849       if (getenv(env_list[i], buffer, len)) {
 850         st->print(env_list[i]);
 851         st->print("=");
 852         st->print_cr(buffer);
 853       }
 854     }
 855   }
 856 }
 857 
 858 void os::print_cpu_info(outputStream* st) {
 859   // cpu
 860   st->print("CPU:");
 861   st->print("total %d", os::processor_count());
 862   // It's not safe to query number of active processors after crash
 863   // st->print("(active %d)", os::active_processor_count());
 864   st->print(" %s", VM_Version::cpu_features());
 865   st->cr();
 866   pd_print_cpu_info(st);
 867 }
 868 
 869 void os::print_date_and_time(outputStream *st) {
 870   time_t tloc;
 871   (void)time(&tloc);
 872   st->print("time: %s", ctime(&tloc));  // ctime adds newline.
 873 
 874   double t = os::elapsedTime();
 875   // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
 876   //       Linux. Must be a bug in glibc ? Workaround is to round "t" to int
 877   //       before printf. We lost some precision, but who cares?
 878   st->print_cr("elapsed time: %d seconds", (int)t);
 879 }
 880 
 881 // moved from debug.cpp (used to be find()) but still called from there
 882 // The verbose parameter is only set by the debug code in one case
 883 void os::print_location(outputStream* st, intptr_t x, bool verbose) {
 884   address addr = (address)x;
 885   CodeBlob* b = CodeCache::find_blob_unsafe(addr);
 886   if (b != NULL) {
 887     if (b->is_buffer_blob()) {
 888       // the interpreter is generated into a buffer blob
 889       InterpreterCodelet* i = Interpreter::codelet_containing(addr);
 890       if (i != NULL) {
 891         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an Interpreter codelet", addr, (int)(addr - i->code_begin()));
 892         i->print_on(st);
 893         return;
 894       }
 895       if (Interpreter::contains(addr)) {
 896         st->print_cr(INTPTR_FORMAT " is pointing into interpreter code"
 897                      " (not bytecode specific)", addr);
 898         return;
 899       }
 900       //
 901       if (AdapterHandlerLibrary::contains(b)) {
 902         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an AdapterHandler", addr, (int)(addr - b->code_begin()));
 903         AdapterHandlerLibrary::print_handler_on(st, b);
 904       }
 905       // the stubroutines are generated into a buffer blob
 906       StubCodeDesc* d = StubCodeDesc::desc_for(addr);
 907       if (d != NULL) {
 908         st->print_cr(INTPTR_FORMAT " is at begin+%d in a stub", addr, (int)(addr - d->begin()));
 909         d->print_on(st);
 910         st->cr();
 911         return;
 912       }
 913       if (StubRoutines::contains(addr)) {
 914         st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) "
 915                      "stub routine", addr);
 916         return;
 917       }
 918       // the InlineCacheBuffer is using stubs generated into a buffer blob
 919       if (InlineCacheBuffer::contains(addr)) {
 920         st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", addr);
 921         return;
 922       }
 923       VtableStub* v = VtableStubs::stub_containing(addr);
 924       if (v != NULL) {
 925         st->print_cr(INTPTR_FORMAT " is at entry_point+%d in a vtable stub", addr, (int)(addr - v->entry_point()));
 926         v->print_on(st);
 927         st->cr();
 928         return;
 929       }
 930     }
 931     nmethod* nm = b->as_nmethod_or_null();
 932     if (nm != NULL) {
 933       ResourceMark rm;
 934       st->print(INTPTR_FORMAT " is at entry_point+%d in (nmethod*)" INTPTR_FORMAT,
 935                 addr, (int)(addr - nm->entry_point()), nm);
 936       if (verbose) {
 937         st->print(" for ");
 938         nm->method()->print_value_on(st);
 939       }
 940       st->cr();
 941       nm->print_nmethod(verbose);
 942       return;
 943     }
 944     st->print_cr(INTPTR_FORMAT " is at code_begin+%d in ", addr, (int)(addr - b->code_begin()));
 945     b->print_on(st);
 946     return;
 947   }
 948 
 949   if (Universe::heap()->is_in(addr)) {
 950     HeapWord* p = Universe::heap()->block_start(addr);
 951     bool print = false;
 952     // If we couldn't find it it just may mean that heap wasn't parseable
 953     // See if we were just given an oop directly
 954     if (p != NULL && Universe::heap()->block_is_obj(p)) {
 955       print = true;
 956     } else if (p == NULL && ((oopDesc*)addr)->is_oop()) {
 957       p = (HeapWord*) addr;
 958       print = true;
 959     }
 960     if (print) {
 961       if (p == (HeapWord*) addr) {
 962         st->print_cr(INTPTR_FORMAT " is an oop", addr);
 963       } else {
 964         st->print_cr(INTPTR_FORMAT " is pointing into object: " INTPTR_FORMAT, addr, p);
 965       }
 966       oop(p)->print_on(st);
 967       return;
 968     }
 969   } else {
 970     if (Universe::heap()->is_in_reserved(addr)) {
 971       st->print_cr(INTPTR_FORMAT " is an unallocated location "
 972                    "in the heap", addr);
 973       return;
 974     }
 975   }
 976   if (JNIHandles::is_global_handle((jobject) addr)) {
 977     st->print_cr(INTPTR_FORMAT " is a global jni handle", addr);
 978     return;
 979   }
 980   if (JNIHandles::is_weak_global_handle((jobject) addr)) {
 981     st->print_cr(INTPTR_FORMAT " is a weak global jni handle", addr);
 982     return;
 983   }
 984 #ifndef PRODUCT
 985   // we don't keep the block list in product mode
 986   if (JNIHandleBlock::any_contains((jobject) addr)) {
 987     st->print_cr(INTPTR_FORMAT " is a local jni handle", addr);
 988     return;
 989   }
 990 #endif
 991 
 992   for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
 993     // Check for privilege stack
 994     if (thread->privileged_stack_top() != NULL &&
 995         thread->privileged_stack_top()->contains(addr)) {
 996       st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack "
 997                    "for thread: " INTPTR_FORMAT, addr, thread);
 998       if (verbose) thread->print_on(st);
 999       return;
1000     }
1001     // If the addr is a java thread print information about that.
1002     if (addr == (address)thread) {
1003       if (verbose) {
1004         thread->print_on(st);
1005       } else {
1006         st->print_cr(INTPTR_FORMAT " is a thread", addr);
1007       }
1008       return;
1009     }
1010     // If the addr is in the stack region for this thread then report that
1011     // and print thread info
1012     if (thread->stack_base() >= addr &&
1013         addr > (thread->stack_base() - thread->stack_size())) {
1014       st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
1015                    INTPTR_FORMAT, addr, thread);
1016       if (verbose) thread->print_on(st);
1017       return;
1018     }
1019 
1020   }
1021 
1022 #ifndef PRODUCT
1023   // Check if in metaspace.
1024   if (ClassLoaderDataGraph::contains((address)addr)) {
1025     // Use addr->print() from the debugger instead (not here)
1026     st->print_cr(INTPTR_FORMAT
1027                  " is pointing into metadata", addr);
1028     return;
1029   }
1030 #endif
1031 
1032   // Try an OS specific find
1033   if (os::find(addr, st)) {
1034     return;
1035   }
1036 
1037   st->print_cr(INTPTR_FORMAT " is an unknown value", addr);
1038 }
1039 
1040 // Looks like all platforms except IA64 can use the same function to check
1041 // if C stack is walkable beyond current frame. The check for fp() is not
1042 // necessary on Sparc, but it's harmless.
1043 bool os::is_first_C_frame(frame* fr) {
1044 #if defined(IA64) && !defined(_WIN32)
1045   // On IA64 we have to check if the callers bsp is still valid
1046   // (i.e. within the register stack bounds).
1047   // Notice: this only works for threads created by the VM and only if
1048   // we walk the current stack!!! If we want to be able to walk
1049   // arbitrary other threads, we'll have to somehow store the thread
1050   // object in the frame.
1051   Thread *thread = Thread::current();
1052   if ((address)fr->fp() <=
1053       thread->register_stack_base() HPUX_ONLY(+ 0x0) LINUX_ONLY(+ 0x50)) {
1054     // This check is a little hacky, because on Linux the first C
1055     // frame's ('start_thread') register stack frame starts at
1056     // "register_stack_base + 0x48" while on HPUX, the first C frame's
1057     // ('__pthread_bound_body') register stack frame seems to really
1058     // start at "register_stack_base".
1059     return true;
1060   } else {
1061     return false;
1062   }
1063 #elif defined(IA64) && defined(_WIN32)
1064   return true;
1065 #else
1066   // Load up sp, fp, sender sp and sender fp, check for reasonable values.
1067   // Check usp first, because if that's bad the other accessors may fault
1068   // on some architectures.  Ditto ufp second, etc.
1069   uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
1070   // sp on amd can be 32 bit aligned.
1071   uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
1072 
1073   uintptr_t usp    = (uintptr_t)fr->sp();
1074   if ((usp & sp_align_mask) != 0) return true;
1075 
1076   uintptr_t ufp    = (uintptr_t)fr->fp();
1077   if ((ufp & fp_align_mask) != 0) return true;
1078 
1079   uintptr_t old_sp = (uintptr_t)fr->sender_sp();
1080   if ((old_sp & sp_align_mask) != 0) return true;
1081   if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
1082 
1083   uintptr_t old_fp = (uintptr_t)fr->link();
1084   if ((old_fp & fp_align_mask) != 0) return true;
1085   if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
1086 
1087   // stack grows downwards; if old_fp is below current fp or if the stack
1088   // frame is too large, either the stack is corrupted or fp is not saved
1089   // on stack (i.e. on x86, ebp may be used as general register). The stack
1090   // is not walkable beyond current frame.
1091   if (old_fp < ufp) return true;
1092   if (old_fp - ufp > 64 * K) return true;
1093 
1094   return false;
1095 #endif
1096 }
1097 
1098 #ifdef ASSERT
1099 extern "C" void test_random() {
1100   const double m = 2147483647;
1101   double mean = 0.0, variance = 0.0, t;
1102   long reps = 10000;
1103   unsigned long seed = 1;
1104 
1105   tty->print_cr("seed %ld for %ld repeats...", seed, reps);
1106   os::init_random(seed);
1107   long num;
1108   for (int k = 0; k < reps; k++) {
1109     num = os::random();
1110     double u = (double)num / m;
1111     assert(u >= 0.0 && u <= 1.0, "bad random number!");
1112 
1113     // calculate mean and variance of the random sequence
1114     mean += u;
1115     variance += (u*u);
1116   }
1117   mean /= reps;
1118   variance /= (reps - 1);
1119 
1120   assert(num == 1043618065, "bad seed");
1121   tty->print_cr("mean of the 1st 10000 numbers: %f", mean);
1122   tty->print_cr("variance of the 1st 10000 numbers: %f", variance);
1123   const double eps = 0.0001;
1124   t = fabsd(mean - 0.5018);
1125   assert(t < eps, "bad mean");
1126   t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355;
1127   assert(t < eps, "bad variance");
1128 }
1129 #endif
1130 
1131 
1132 // Set up the boot classpath.
1133 
1134 char* os::format_boot_path(const char* format_string,
1135                            const char* home,
1136                            int home_len,
1137                            char fileSep,
1138                            char pathSep) {
1139     assert((fileSep == '/' && pathSep == ':') ||
1140            (fileSep == '\\' && pathSep == ';'), "unexpected seperator chars");
1141 
1142     // Scan the format string to determine the length of the actual
1143     // boot classpath, and handle platform dependencies as well.
1144     int formatted_path_len = 0;
1145     const char* p;
1146     for (p = format_string; *p != 0; ++p) {
1147         if (*p == '%') formatted_path_len += home_len - 1;
1148         ++formatted_path_len;
1149     }
1150 
1151     char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal);
1152     if (formatted_path == NULL) {
1153         return NULL;
1154     }
1155 
1156     // Create boot classpath from format, substituting separator chars and
1157     // java home directory.
1158     char* q = formatted_path;
1159     for (p = format_string; *p != 0; ++p) {
1160         switch (*p) {
1161         case '%':
1162             strcpy(q, home);
1163             q += home_len;
1164             break;
1165         case '/':
1166             *q++ = fileSep;
1167             break;
1168         case ':':
1169             *q++ = pathSep;
1170             break;
1171         default:
1172             *q++ = *p;
1173         }
1174     }
1175     *q = '\0';
1176 
1177     assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
1178     return formatted_path;
1179 }
1180 
1181 
1182 bool os::set_boot_path(char fileSep, char pathSep) {
1183     const char* home = Arguments::get_java_home();
1184     int home_len = (int)strlen(home);
1185 
1186     static const char* meta_index_dir_format = "%/lib/";
1187     static const char* meta_index_format = "%/lib/meta-index";
1188     char* meta_index = format_boot_path(meta_index_format, home, home_len, fileSep, pathSep);
1189     if (meta_index == NULL) return false;
1190     char* meta_index_dir = format_boot_path(meta_index_dir_format, home, home_len, fileSep, pathSep);
1191     if (meta_index_dir == NULL) return false;
1192     Arguments::set_meta_index_path(meta_index, meta_index_dir);
1193 
1194     // Any modification to the JAR-file list, for the boot classpath must be
1195     // aligned with install/install/make/common/Pack.gmk. Note: boot class
1196     // path class JARs, are stripped for StackMapTable to reduce download size.
1197     static const char classpath_format[] =
1198         "%/lib/resources.jar:"
1199         "%/lib/rt.jar:"
1200         "%/lib/sunrsasign.jar:"
1201         "%/lib/jsse.jar:"
1202         "%/lib/jce.jar:"
1203         "%/lib/charsets.jar:"
1204         "%/lib/jfr.jar:"
1205 #ifdef __APPLE__
1206         "%/lib/JObjC.jar:"
1207 #endif
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_min_size, size_t region_max_size,
1335                                 uint min_pages)
1336 {
1337   assert(min_pages > 0, "sanity");
1338   if (UseLargePages) {
1339     const size_t max_page_size = region_max_size / min_pages;
1340 
1341     for (unsigned int i = 0; _page_sizes[i] != 0; ++i) {
1342       const size_t sz = _page_sizes[i];
1343       const size_t mask = sz - 1;
1344       if ((region_min_size & mask) == 0 && (region_max_size & mask) == 0) {
1345         // The largest page size with no fragmentation.
1346         return sz;
1347       }
1348 
1349       if (sz <= max_page_size) {
1350         // The largest page size that satisfies the min_pages requirement.
1351         return sz;
1352       }
1353     }
1354   }
1355 
1356   return vm_page_size();
1357 }
1358 
1359 #ifndef PRODUCT
1360 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count)
1361 {
1362   if (TracePageSizes) {
1363     tty->print("%s: ", str);
1364     for (int i = 0; i < count; ++i) {
1365       tty->print(" " SIZE_FORMAT, page_sizes[i]);
1366     }
1367     tty->cr();
1368   }
1369 }
1370 
1371 void os::trace_page_sizes(const char* str, const size_t region_min_size,
1372                           const size_t region_max_size, const size_t page_size,
1373                           const char* base, const size_t size)
1374 {
1375   if (TracePageSizes) {
1376     tty->print_cr("%s:  min=" SIZE_FORMAT " max=" SIZE_FORMAT
1377                   " pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT
1378                   " size=" SIZE_FORMAT,
1379                   str, region_min_size, region_max_size,
1380                   page_size, base, size);
1381   }
1382 }
1383 #endif  // #ifndef PRODUCT
1384 
1385 // This is the working definition of a server class machine:
1386 // >= 2 physical CPU's and >=2GB of memory, with some fuzz
1387 // because the graphics memory (?) sometimes masks physical memory.
1388 // If you want to change the definition of a server class machine
1389 // on some OS or platform, e.g., >=4GB on Windohs platforms,
1390 // then you'll have to parameterize this method based on that state,
1391 // as was done for logical processors here, or replicate and
1392 // specialize this method for each platform.  (Or fix os to have
1393 // some inheritance structure and use subclassing.  Sigh.)
1394 // If you want some platform to always or never behave as a server
1395 // class machine, change the setting of AlwaysActAsServerClassMachine
1396 // and NeverActAsServerClassMachine in globals*.hpp.
1397 bool os::is_server_class_machine() {
1398   // First check for the early returns
1399   if (NeverActAsServerClassMachine) {
1400     return false;
1401   }
1402   if (AlwaysActAsServerClassMachine) {
1403     return true;
1404   }
1405   // Then actually look at the machine
1406   bool         result            = false;
1407   const unsigned int    server_processors = 2;
1408   const julong server_memory     = 2UL * G;
1409   // We seem not to get our full complement of memory.
1410   //     We allow some part (1/8?) of the memory to be "missing",
1411   //     based on the sizes of DIMMs, and maybe graphics cards.
1412   const julong missing_memory   = 256UL * M;
1413 
1414   /* Is this a server class machine? */
1415   if ((os::active_processor_count() >= (int)server_processors) &&
1416       (os::physical_memory() >= (server_memory - missing_memory))) {
1417     const unsigned int logical_processors =
1418       VM_Version::logical_processors_per_package();
1419     if (logical_processors > 1) {
1420       const unsigned int physical_packages =
1421         os::active_processor_count() / logical_processors;
1422       if (physical_packages > server_processors) {
1423         result = true;
1424       }
1425     } else {
1426       result = true;
1427     }
1428   }
1429   return result;
1430 }
1431 
1432 // Read file line by line, if line is longer than bsize,
1433 // skip rest of line.
1434 int os::get_line_chars(int fd, char* buf, const size_t bsize){
1435   size_t sz, i = 0;
1436 
1437   // read until EOF, EOL or buf is full
1438   while ((sz = (int) read(fd, &buf[i], 1)) == 1 && i < (bsize-2) && buf[i] != '\n') {
1439      ++i;
1440   }
1441 
1442   if (buf[i] == '\n') {
1443     // EOL reached so ignore EOL character and return
1444 
1445     buf[i] = 0;
1446     return (int) i;
1447   }
1448 
1449   buf[i+1] = 0;
1450 
1451   if (sz != 1) {
1452     // EOF reached. if we read chars before EOF return them and
1453     // return EOF on next call otherwise return EOF
1454 
1455     return (i == 0) ? -1 : (int) i;
1456   }
1457 
1458   // line is longer than size of buf, skip to EOL
1459   char ch;
1460   while (read(fd, &ch, 1) == 1 && ch != '\n') {
1461     // Do nothing
1462   }
1463 
1464   // return initial part of line that fits in buf.
1465   // If we reached EOF, it will be returned on next call.
1466 
1467   return (int) i;
1468 }
1469 
1470 void os::SuspendedThreadTask::run() {
1471   assert(Threads_lock->owned_by_self() || (_thread == VMThread::vm_thread()), "must have threads lock to call this");
1472   internal_do_task();
1473   _done = true;
1474 }
1475 
1476 bool os::create_stack_guard_pages(char* addr, size_t bytes) {
1477   return os::pd_create_stack_guard_pages(addr, bytes);
1478 }
1479 
1480 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint) {
1481   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1482   if (result != NULL) {
1483     MemTracker::record_virtual_memory_reserve((address)result, bytes, mtNone, CALLER_PC);
1484   }
1485 
1486   return result;
1487 }
1488 
1489 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint,
1490    MEMFLAGS flags) {
1491   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1492   if (result != NULL) {
1493     MemTracker::record_virtual_memory_reserve((address)result, bytes, mtNone, CALLER_PC);
1494     MemTracker::record_virtual_memory_type((address)result, flags);
1495   }
1496 
1497   return result;
1498 }
1499 
1500 char* os::attempt_reserve_memory_at(size_t bytes, char* addr) {
1501   char* result = pd_attempt_reserve_memory_at(bytes, addr);
1502   if (result != NULL) {
1503     MemTracker::record_virtual_memory_reserve((address)result, bytes, mtNone, CALLER_PC);
1504   }
1505   return result;
1506 }
1507 
1508 void os::split_reserved_memory(char *base, size_t size,
1509                                  size_t split, bool realloc) {
1510   pd_split_reserved_memory(base, size, split, realloc);
1511 }
1512 
1513 bool os::commit_memory(char* addr, size_t bytes, bool executable) {
1514   bool res = pd_commit_memory(addr, bytes, executable);
1515   if (res) {
1516     MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1517   }
1518   return res;
1519 }
1520 
1521 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
1522                               bool executable) {
1523   bool res = os::pd_commit_memory(addr, size, alignment_hint, executable);
1524   if (res) {
1525     MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1526   }
1527   return res;
1528 }
1529 
1530 void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable,
1531                                const char* mesg) {
1532   pd_commit_memory_or_exit(addr, bytes, executable, mesg);
1533   MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1534 }
1535 
1536 void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint,
1537                                bool executable, const char* mesg) {
1538   os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg);
1539   MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1540 }
1541 
1542 bool os::uncommit_memory(char* addr, size_t bytes) {
1543   MemTracker::Tracker tkr = MemTracker::get_virtual_memory_uncommit_tracker();
1544   bool res = pd_uncommit_memory(addr, bytes);
1545   if (res) {
1546     tkr.record((address)addr, bytes);
1547   } else {
1548     tkr.discard();
1549   }
1550   return res;
1551 }
1552 
1553 bool os::release_memory(char* addr, size_t bytes) {
1554   MemTracker::Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1555   bool res = pd_release_memory(addr, bytes);
1556   if (res) {
1557     tkr.record((address)addr, bytes);
1558   } else {
1559     tkr.discard();
1560   }
1561   return res;
1562 }
1563 
1564 
1565 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
1566                            char *addr, size_t bytes, bool read_only,
1567                            bool allow_exec) {
1568   char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec);
1569   if (result != NULL) {
1570     MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, mtNone, CALLER_PC);
1571   }
1572   return result;
1573 }
1574 
1575 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
1576                              char *addr, size_t bytes, bool read_only,
1577                              bool allow_exec) {
1578   return pd_remap_memory(fd, file_name, file_offset, addr, bytes,
1579                     read_only, allow_exec);
1580 }
1581 
1582 bool os::unmap_memory(char *addr, size_t bytes) {
1583   MemTracker::Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1584   bool result = pd_unmap_memory(addr, bytes);
1585   if (result) {
1586     tkr.record((address)addr, bytes);
1587   } else {
1588     tkr.discard();
1589   }
1590   return result;
1591 }
1592 
1593 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
1594   pd_free_memory(addr, bytes, alignment_hint);
1595 }
1596 
1597 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
1598   pd_realign_memory(addr, bytes, alignment_hint);
1599 }
1600 
1601 #ifndef TARGET_OS_FAMILY_windows
1602 /* try to switch state from state "from" to state "to"
1603  * returns the state set after the method is complete
1604  */
1605 os::SuspendResume::State os::SuspendResume::switch_state(os::SuspendResume::State from,
1606                                                          os::SuspendResume::State to)
1607 {
1608   os::SuspendResume::State result =
1609     (os::SuspendResume::State) Atomic::cmpxchg((jint) to, (jint *) &_state, (jint) from);
1610   if (result == from) {
1611     // success
1612     return to;
1613   }
1614   return result;
1615 }
1616 #endif