1 /*
   2  * Copyright (c) 1997, 2011, 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 "services/attachListener.hpp"
  48 #include "services/memTracker.hpp"
  49 #include "services/threadService.hpp"
  50 #include "utilities/defaultStream.hpp"
  51 #include "utilities/events.hpp"
  52 #ifdef TARGET_OS_FAMILY_linux
  53 # include "os_linux.inline.hpp"
  54 # include "thread_linux.inline.hpp"
  55 #endif
  56 #ifdef TARGET_OS_FAMILY_solaris
  57 # include "os_solaris.inline.hpp"
  58 # include "thread_solaris.inline.hpp"
  59 #endif
  60 #ifdef TARGET_OS_FAMILY_windows
  61 # include "os_windows.inline.hpp"
  62 # include "thread_windows.inline.hpp"
  63 #endif
  64 #ifdef TARGET_OS_FAMILY_bsd
  65 # include "os_bsd.inline.hpp"
  66 # include "thread_bsd.inline.hpp"
  67 #endif
  68 
  69 # include <signal.h>
  70 
  71 OSThread*         os::_starting_thread    = NULL;
  72 address           os::_polling_page       = NULL;
  73 volatile int32_t* os::_mem_serialize_page = NULL;
  74 uintptr_t         os::_serialize_page_mask = 0;
  75 long              os::_rand_seed          = 1;
  76 int               os::_processor_count    = 0;
  77 size_t            os::_page_sizes[os::page_sizes_max];
  78 
  79 #ifndef PRODUCT
  80 julong os::num_mallocs = 0;         // # of calls to malloc/realloc
  81 julong os::alloc_bytes = 0;         // # of bytes allocated
  82 julong os::num_frees = 0;           // # of calls to free
  83 julong os::free_bytes = 0;          // # of bytes freed
  84 #endif
  85 
  86 void os_init_globals() {
  87   // Called from init_globals().
  88   // See Threads::create_vm() in thread.cpp, and init.cpp.
  89   os::init_globals();
  90 }
  91 
  92 // Fill in buffer with current local time as an ISO-8601 string.
  93 // E.g., yyyy-mm-ddThh:mm:ss-zzzz.
  94 // Returns buffer, or NULL if it failed.
  95 // This would mostly be a call to
  96 //     strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
  97 // except that on Windows the %z behaves badly, so we do it ourselves.
  98 // Also, people wanted milliseconds on there,
  99 // and strftime doesn't do milliseconds.
 100 char* os::iso8601_time(char* buffer, size_t buffer_length) {
 101   // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
 102   //                                      1         2
 103   //                             12345678901234567890123456789
 104   static const char* iso8601_format =
 105     "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d";
 106   static const size_t needed_buffer = 29;
 107 
 108   // Sanity check the arguments
 109   if (buffer == NULL) {
 110     assert(false, "NULL buffer");
 111     return NULL;
 112   }
 113   if (buffer_length < needed_buffer) {
 114     assert(false, "buffer_length too small");
 115     return NULL;
 116   }
 117   // Get the current time
 118   jlong milliseconds_since_19700101 = javaTimeMillis();
 119   const int milliseconds_per_microsecond = 1000;
 120   const time_t seconds_since_19700101 =
 121     milliseconds_since_19700101 / milliseconds_per_microsecond;
 122   const int milliseconds_after_second =
 123     milliseconds_since_19700101 % milliseconds_per_microsecond;
 124   // Convert the time value to a tm and timezone variable
 125   struct tm time_struct;
 126   if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
 127     assert(false, "Failed localtime_pd");
 128     return NULL;
 129   }
 130 #if defined(_ALLBSD_SOURCE)
 131   const time_t zone = (time_t) time_struct.tm_gmtoff;
 132 #else
 133   const time_t zone = timezone;
 134 #endif
 135 
 136   // If daylight savings time is in effect,
 137   // we are 1 hour East of our time zone
 138   const time_t seconds_per_minute = 60;
 139   const time_t minutes_per_hour = 60;
 140   const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
 141   time_t UTC_to_local = zone;
 142   if (time_struct.tm_isdst > 0) {
 143     UTC_to_local = UTC_to_local - seconds_per_hour;
 144   }
 145   // Compute the time zone offset.
 146   //    localtime_pd() sets timezone to the difference (in seconds)
 147   //    between UTC and and local time.
 148   //    ISO 8601 says we need the difference between local time and UTC,
 149   //    we change the sign of the localtime_pd() result.
 150   const time_t local_to_UTC = -(UTC_to_local);
 151   // Then we have to figure out if if we are ahead (+) or behind (-) UTC.
 152   char sign_local_to_UTC = '+';
 153   time_t abs_local_to_UTC = local_to_UTC;
 154   if (local_to_UTC < 0) {
 155     sign_local_to_UTC = '-';
 156     abs_local_to_UTC = -(abs_local_to_UTC);
 157   }
 158   // Convert time zone offset seconds to hours and minutes.
 159   const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
 160   const time_t zone_min =
 161     ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
 162 
 163   // Print an ISO 8601 date and time stamp into the buffer
 164   const int year = 1900 + time_struct.tm_year;
 165   const int month = 1 + time_struct.tm_mon;
 166   const int printed = jio_snprintf(buffer, buffer_length, iso8601_format,
 167                                    year,
 168                                    month,
 169                                    time_struct.tm_mday,
 170                                    time_struct.tm_hour,
 171                                    time_struct.tm_min,
 172                                    time_struct.tm_sec,
 173                                    milliseconds_after_second,
 174                                    sign_local_to_UTC,
 175                                    zone_hours,
 176                                    zone_min);
 177   if (printed == 0) {
 178     assert(false, "Failed jio_printf");
 179     return NULL;
 180   }
 181   return buffer;
 182 }
 183 
 184 OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
 185 #ifdef ASSERT
 186   if (!(!thread->is_Java_thread() ||
 187          Thread::current() == thread  ||
 188          Threads_lock->owned_by_self()
 189          || thread->is_Compiler_thread()
 190         )) {
 191     assert(false, "possibility of dangling Thread pointer");
 192   }
 193 #endif
 194 
 195   if (p >= MinPriority && p <= MaxPriority) {
 196     int priority = java_to_os_priority[p];
 197     return set_native_priority(thread, priority);
 198   } else {
 199     assert(false, "Should not happen");
 200     return OS_ERR;
 201   }
 202 }
 203 
 204 
 205 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
 206   int p;
 207   int os_prio;
 208   OSReturn ret = get_native_priority(thread, &os_prio);
 209   if (ret != OS_OK) return ret;
 210 
 211   for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
 212   priority = (ThreadPriority)p;
 213   return OS_OK;
 214 }
 215 
 216 
 217 // --------------------- sun.misc.Signal (optional) ---------------------
 218 
 219 
 220 // SIGBREAK is sent by the keyboard to query the VM state
 221 #ifndef SIGBREAK
 222 #define SIGBREAK SIGQUIT
 223 #endif
 224 
 225 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
 226 
 227 
 228 static void signal_thread_entry(JavaThread* thread, TRAPS) {
 229   os::set_priority(thread, NearMaxPriority);
 230   while (true) {
 231     int sig;
 232     {
 233       // FIXME : Currently we have not decieded what should be the status
 234       //         for this java thread blocked here. Once we decide about
 235       //         that we should fix this.
 236       sig = os::signal_wait();
 237     }
 238     if (sig == os::sigexitnum_pd()) {
 239        // Terminate the signal thread
 240        return;
 241     }
 242 
 243     switch (sig) {
 244       case SIGBREAK: {
 245         // Check if the signal is a trigger to start the Attach Listener - in that
 246         // case don't print stack traces.
 247         if (!DisableAttachMechanism && AttachListener::is_init_trigger()) {
 248           continue;
 249         }
 250         // Print stack traces
 251         // Any SIGBREAK operations added here should make sure to flush
 252         // the output stream (e.g. tty->flush()) after output.  See 4803766.
 253         // Each module also prints an extra carriage return after its output.
 254         VM_PrintThreads op;
 255         VMThread::execute(&op);
 256         VM_PrintJNI jni_op;
 257         VMThread::execute(&jni_op);
 258         VM_FindDeadlocks op1(tty);
 259         VMThread::execute(&op1);
 260         Universe::print_heap_at_SIGBREAK();
 261         if (PrintClassHistogram) {
 262           VM_GC_HeapInspection op1(gclog_or_tty, true /* force full GC before heap inspection */,
 263                                    true /* need_prologue */);
 264           VMThread::execute(&op1);
 265         }
 266         if (JvmtiExport::should_post_data_dump()) {
 267           JvmtiExport::post_data_dump();
 268         }
 269         break;
 270       }
 271       default: {
 272         // Dispatch the signal to java
 273         HandleMark hm(THREAD);
 274         klassOop k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_Signal(), THREAD);
 275         KlassHandle klass (THREAD, k);
 276         if (klass.not_null()) {
 277           JavaValue result(T_VOID);
 278           JavaCallArguments args;
 279           args.push_int(sig);
 280           JavaCalls::call_static(
 281             &result,
 282             klass,
 283             vmSymbols::dispatch_name(),
 284             vmSymbols::int_void_signature(),
 285             &args,
 286             THREAD
 287           );
 288         }
 289         if (HAS_PENDING_EXCEPTION) {
 290           // tty is initialized early so we don't expect it to be null, but
 291           // if it is we can't risk doing an initialization that might
 292           // trigger additional out-of-memory conditions
 293           if (tty != NULL) {
 294             char klass_name[256];
 295             char tmp_sig_name[16];
 296             const char* sig_name = "UNKNOWN";
 297             instanceKlass::cast(PENDING_EXCEPTION->klass())->
 298               name()->as_klass_external_name(klass_name, 256);
 299             if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
 300               sig_name = tmp_sig_name;
 301             warning("Exception %s occurred dispatching signal %s to handler"
 302                     "- the VM may need to be forcibly terminated",
 303                     klass_name, sig_name );
 304           }
 305           CLEAR_PENDING_EXCEPTION;
 306         }
 307       }
 308     }
 309   }
 310 }
 311 
 312 
 313 void os::signal_init() {
 314   if (!ReduceSignalUsage) {
 315     // Setup JavaThread for processing signals
 316     EXCEPTION_MARK;
 317     klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
 318     instanceKlassHandle klass (THREAD, k);
 319     instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
 320 
 321     const char thread_name[] = "Signal Dispatcher";
 322     Handle string = java_lang_String::create_from_str(thread_name, CHECK);
 323 
 324     // Initialize thread_oop to put it into the system threadGroup
 325     Handle thread_group (THREAD, Universe::system_thread_group());
 326     JavaValue result(T_VOID);
 327     JavaCalls::call_special(&result, thread_oop,
 328                            klass,
 329                            vmSymbols::object_initializer_name(),
 330                            vmSymbols::threadgroup_string_void_signature(),
 331                            thread_group,
 332                            string,
 333                            CHECK);
 334 
 335     KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
 336     JavaCalls::call_special(&result,
 337                             thread_group,
 338                             group,
 339                             vmSymbols::add_method_name(),
 340                             vmSymbols::thread_void_signature(),
 341                             thread_oop,         // ARG 1
 342                             CHECK);
 343 
 344     os::signal_init_pd();
 345 
 346     { MutexLocker mu(Threads_lock);
 347       JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
 348 
 349       // At this point it may be possible that no osthread was created for the
 350       // JavaThread due to lack of memory. We would have to throw an exception
 351       // in that case. However, since this must work and we do not allow
 352       // exceptions anyway, check and abort if this fails.
 353       if (signal_thread == NULL || signal_thread->osthread() == NULL) {
 354         vm_exit_during_initialization("java.lang.OutOfMemoryError",
 355                                       "unable to create new native thread");
 356       }
 357 
 358       java_lang_Thread::set_thread(thread_oop(), signal_thread);
 359       java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
 360       java_lang_Thread::set_daemon(thread_oop());
 361 
 362       signal_thread->set_threadObj(thread_oop());
 363       Threads::add(signal_thread);
 364       Thread::start(signal_thread);
 365     }
 366     // Handle ^BREAK
 367     os::signal(SIGBREAK, os::user_handler());
 368   }
 369 }
 370 
 371 
 372 void os::terminate_signal_thread() {
 373   if (!ReduceSignalUsage)
 374     signal_notify(sigexitnum_pd());
 375 }
 376 
 377 
 378 // --------------------- loading libraries ---------------------
 379 
 380 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
 381 extern struct JavaVM_ main_vm;
 382 
 383 static void* _native_java_library = NULL;
 384 
 385 void* os::native_java_library() {
 386   if (_native_java_library == NULL) {
 387     char buffer[JVM_MAXPATHLEN];
 388     char ebuf[1024];
 389 
 390     // Try to load verify dll first. In 1.3 java dll depends on it and is not
 391     // always able to find it when the loading executable is outside the JDK.
 392     // In order to keep working with 1.2 we ignore any loading errors.
 393     dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "verify");
 394     dll_load(buffer, ebuf, sizeof(ebuf));
 395 
 396     // Load java dll
 397     dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "java");
 398     _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
 399     if (_native_java_library == NULL) {
 400       vm_exit_during_initialization("Unable to load native library", ebuf);
 401     }
 402 
 403 #if defined(__OpenBSD__)
 404     // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so
 405     // ignore errors
 406     dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "net");
 407     dll_load(buffer, ebuf, sizeof(ebuf));
 408 #endif
 409   }
 410   static jboolean onLoaded = JNI_FALSE;
 411   if (onLoaded) {
 412     // We may have to wait to fire OnLoad until TLS is initialized.
 413     if (ThreadLocalStorage::is_initialized()) {
 414       // The JNI_OnLoad handling is normally done by method load in
 415       // java.lang.ClassLoader$NativeLibrary, but the VM loads the base library
 416       // explicitly so we have to check for JNI_OnLoad as well
 417       const char *onLoadSymbols[] = JNI_ONLOAD_SYMBOLS;
 418       JNI_OnLoad_t JNI_OnLoad = CAST_TO_FN_PTR(
 419           JNI_OnLoad_t, dll_lookup(_native_java_library, onLoadSymbols[0]));
 420       if (JNI_OnLoad != NULL) {
 421         JavaThread* thread = JavaThread::current();
 422         ThreadToNativeFromVM ttn(thread);
 423         HandleMark hm(thread);
 424         jint ver = (*JNI_OnLoad)(&main_vm, NULL);
 425         onLoaded = JNI_TRUE;
 426         if (!Threads::is_supported_jni_version_including_1_1(ver)) {
 427           vm_exit_during_initialization("Unsupported JNI version");
 428         }
 429       }
 430     }
 431   }
 432   return _native_java_library;
 433 }
 434 
 435 // --------------------- heap allocation utilities ---------------------
 436 
 437 char *os::strdup(const char *str, MEMFLAGS flags) {
 438   size_t size = strlen(str);
 439   char *dup_str = (char *)malloc(size + 1, flags);
 440   if (dup_str == NULL) return NULL;
 441   strcpy(dup_str, str);
 442   return dup_str;
 443 }
 444 
 445 
 446 
 447 #ifdef ASSERT
 448 #define space_before             (MallocCushion + sizeof(double))
 449 #define space_after              MallocCushion
 450 #define size_addr_from_base(p)   (size_t*)(p + space_before - sizeof(size_t))
 451 #define size_addr_from_obj(p)    ((size_t*)p - 1)
 452 // MallocCushion: size of extra cushion allocated around objects with +UseMallocOnly
 453 // NB: cannot be debug variable, because these aren't set from the command line until
 454 // *after* the first few allocs already happened
 455 #define MallocCushion            16
 456 #else
 457 #define space_before             0
 458 #define space_after              0
 459 #define size_addr_from_base(p)   should not use w/o ASSERT
 460 #define size_addr_from_obj(p)    should not use w/o ASSERT
 461 #define MallocCushion            0
 462 #endif
 463 #define paranoid                 0  /* only set to 1 if you suspect checking code has bug */
 464 
 465 #ifdef ASSERT
 466 inline size_t get_size(void* obj) {
 467   size_t size = *size_addr_from_obj(obj);
 468   if (size < 0) {
 469     fatal(err_msg("free: size field of object #" PTR_FORMAT " was overwritten ("
 470                   SIZE_FORMAT ")", obj, size));
 471   }
 472   return size;
 473 }
 474 
 475 u_char* find_cushion_backwards(u_char* start) {
 476   u_char* p = start;
 477   while (p[ 0] != badResourceValue || p[-1] != badResourceValue ||
 478          p[-2] != badResourceValue || p[-3] != badResourceValue) p--;
 479   // ok, we have four consecutive marker bytes; find start
 480   u_char* q = p - 4;
 481   while (*q == badResourceValue) q--;
 482   return q + 1;
 483 }
 484 
 485 u_char* find_cushion_forwards(u_char* start) {
 486   u_char* p = start;
 487   while (p[0] != badResourceValue || p[1] != badResourceValue ||
 488          p[2] != badResourceValue || p[3] != badResourceValue) p++;
 489   // ok, we have four consecutive marker bytes; find end of cushion
 490   u_char* q = p + 4;
 491   while (*q == badResourceValue) q++;
 492   return q - MallocCushion;
 493 }
 494 
 495 void print_neighbor_blocks(void* ptr) {
 496   // find block allocated before ptr (not entirely crash-proof)
 497   if (MallocCushion < 4) {
 498     tty->print_cr("### cannot find previous block (MallocCushion < 4)");
 499     return;
 500   }
 501   u_char* start_of_this_block = (u_char*)ptr - space_before;
 502   u_char* end_of_prev_block_data = start_of_this_block - space_after -1;
 503   // look for cushion in front of prev. block
 504   u_char* start_of_prev_block = find_cushion_backwards(end_of_prev_block_data);
 505   ptrdiff_t size = *size_addr_from_base(start_of_prev_block);
 506   u_char* obj = start_of_prev_block + space_before;
 507   if (size <= 0 ) {
 508     // start is bad; mayhave been confused by OS data inbetween objects
 509     // search one more backwards
 510     start_of_prev_block = find_cushion_backwards(start_of_prev_block);
 511     size = *size_addr_from_base(start_of_prev_block);
 512     obj = start_of_prev_block + space_before;
 513   }
 514 
 515   if (start_of_prev_block + space_before + size + space_after == start_of_this_block) {
 516     tty->print_cr("### previous object: " PTR_FORMAT " (" SSIZE_FORMAT " bytes)", obj, size);
 517   } else {
 518     tty->print_cr("### previous object (not sure if correct): " PTR_FORMAT " (" SSIZE_FORMAT " bytes)", obj, size);
 519   }
 520 
 521   // now find successor block
 522   u_char* start_of_next_block = (u_char*)ptr + *size_addr_from_obj(ptr) + space_after;
 523   start_of_next_block = find_cushion_forwards(start_of_next_block);
 524   u_char* next_obj = start_of_next_block + space_before;
 525   ptrdiff_t next_size = *size_addr_from_base(start_of_next_block);
 526   if (start_of_next_block[0] == badResourceValue &&
 527       start_of_next_block[1] == badResourceValue &&
 528       start_of_next_block[2] == badResourceValue &&
 529       start_of_next_block[3] == badResourceValue) {
 530     tty->print_cr("### next object: " PTR_FORMAT " (" SSIZE_FORMAT " bytes)", next_obj, next_size);
 531   } else {
 532     tty->print_cr("### next object (not sure if correct): " PTR_FORMAT " (" SSIZE_FORMAT " bytes)", next_obj, next_size);
 533   }
 534 }
 535 
 536 
 537 void report_heap_error(void* memblock, void* bad, const char* where) {
 538   tty->print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees);
 539   tty->print_cr("## memory stomp: byte at " PTR_FORMAT " %s object " PTR_FORMAT, bad, where, memblock);
 540   print_neighbor_blocks(memblock);
 541   fatal("memory stomping error");
 542 }
 543 
 544 void verify_block(void* memblock) {
 545   size_t size = get_size(memblock);
 546   if (MallocCushion) {
 547     u_char* ptr = (u_char*)memblock - space_before;
 548     for (int i = 0; i < MallocCushion; i++) {
 549       if (ptr[i] != badResourceValue) {
 550         report_heap_error(memblock, ptr+i, "in front of");
 551       }
 552     }
 553     u_char* end = (u_char*)memblock + size + space_after;
 554     for (int j = -MallocCushion; j < 0; j++) {
 555       if (end[j] != badResourceValue) {
 556         report_heap_error(memblock, end+j, "after");
 557       }
 558     }
 559   }
 560 }
 561 #endif
 562 
 563 void* os::malloc(size_t size, MEMFLAGS memflags, address caller) {
 564   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 565   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 566 
 567   if (size == 0) {
 568     // return a valid pointer if size is zero
 569     // if NULL is returned the calling functions assume out of memory.
 570     size = 1;
 571   }
 572 
 573   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 574   u_char* ptr = (u_char*)::malloc(size + space_before + space_after);
 575 
 576 #ifdef ASSERT
 577   if (ptr == NULL) return NULL;
 578   if (MallocCushion) {
 579     for (u_char* p = ptr; p < ptr + MallocCushion; p++) *p = (u_char)badResourceValue;
 580     u_char* end = ptr + space_before + size;
 581     for (u_char* pq = ptr+MallocCushion; pq < end; pq++) *pq = (u_char)uninitBlockPad;
 582     for (u_char* q = end; q < end + MallocCushion; q++) *q = (u_char)badResourceValue;
 583   }
 584   // put size just before data
 585   *size_addr_from_base(ptr) = size;
 586 #endif
 587   u_char* memblock = ptr + space_before;
 588   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 589     tty->print_cr("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, memblock);
 590     breakpoint();
 591   }
 592   debug_only(if (paranoid) verify_block(memblock));
 593   if (PrintMalloc && tty != NULL) tty->print_cr("os::malloc " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, memblock);
 594 
 595   // we do not track MallocCushion memory
 596     MemTracker::record_malloc((address)memblock, size, memflags, caller == 0 ? CALLER_PC : caller);
 597 
 598   return memblock;
 599 }
 600 
 601 
 602 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, address caller) {
 603 #ifndef ASSERT
 604   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 605   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 606   void* ptr = ::realloc(memblock, size);
 607   if (ptr != NULL) {
 608     MemTracker::record_realloc((address)memblock, (address)ptr, size, memflags,
 609      caller == 0 ? CALLER_PC : caller);
 610   }
 611   return ptr;
 612 #else
 613   if (memblock == NULL) {
 614     return malloc(size, memflags, (caller == 0 ? CALLER_PC : caller));
 615   }
 616   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 617     tty->print_cr("os::realloc caught " PTR_FORMAT, memblock);
 618     breakpoint();
 619   }
 620   verify_block(memblock);
 621   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 622   if (size == 0) return NULL;
 623   // always move the block
 624   void* ptr = malloc(size, memflags, caller == 0 ? CALLER_PC : caller);
 625   if (PrintMalloc) tty->print_cr("os::remalloc " SIZE_FORMAT " bytes, " PTR_FORMAT " --> " PTR_FORMAT, size, memblock, ptr);
 626   // Copy to new memory if malloc didn't fail
 627   if ( ptr != NULL ) {
 628     memcpy(ptr, memblock, MIN2(size, get_size(memblock)));
 629     if (paranoid) verify_block(ptr);
 630     if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
 631       tty->print_cr("os::realloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, ptr);
 632       breakpoint();
 633     }
 634     free(memblock);
 635   }
 636   return ptr;
 637 #endif
 638 }
 639 
 640 
 641 void  os::free(void *memblock, MEMFLAGS memflags) {
 642   NOT_PRODUCT(inc_stat_counter(&num_frees, 1));
 643 #ifdef ASSERT
 644   if (memblock == NULL) return;
 645   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 646     if (tty != NULL) tty->print_cr("os::free caught " PTR_FORMAT, memblock);
 647     breakpoint();
 648   }
 649   verify_block(memblock);
 650   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
 651   // Added by detlefs.
 652   if (MallocCushion) {
 653     u_char* ptr = (u_char*)memblock - space_before;
 654     for (u_char* p = ptr; p < ptr + MallocCushion; p++) {
 655       guarantee(*p == badResourceValue,
 656                 "Thing freed should be malloc result.");
 657       *p = (u_char)freeBlockPad;
 658     }
 659     size_t size = get_size(memblock);
 660     inc_stat_counter(&free_bytes, size);
 661     u_char* end = ptr + space_before + size;
 662     for (u_char* q = end; q < end + MallocCushion; q++) {
 663       guarantee(*q == badResourceValue,
 664                 "Thing freed should be malloc result.");
 665       *q = (u_char)freeBlockPad;
 666     }
 667     if (PrintMalloc && tty != NULL)
 668       fprintf(stderr, "os::free " SIZE_FORMAT " bytes --> " PTR_FORMAT "\n", size, (uintptr_t)memblock);
 669   } else if (PrintMalloc && tty != NULL) {
 670     // tty->print_cr("os::free %p", memblock);
 671     fprintf(stderr, "os::free " PTR_FORMAT "\n", (uintptr_t)memblock);
 672   }
 673 #endif
 674   MemTracker::record_free((address)memblock, memflags);
 675 
 676   ::free((char*)memblock - space_before);
 677 }
 678 
 679 void os::init_random(long initval) {
 680   _rand_seed = initval;
 681 }
 682 
 683 
 684 long os::random() {
 685   /* standard, well-known linear congruential random generator with
 686    * next_rand = (16807*seed) mod (2**31-1)
 687    * see
 688    * (1) "Random Number Generators: Good Ones Are Hard to Find",
 689    *      S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
 690    * (2) "Two Fast Implementations of the 'Minimal Standard' Random
 691    *     Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
 692   */
 693   const long a = 16807;
 694   const unsigned long m = 2147483647;
 695   const long q = m / a;        assert(q == 127773, "weird math");
 696   const long r = m % a;        assert(r == 2836, "weird math");
 697 
 698   // compute az=2^31p+q
 699   unsigned long lo = a * (long)(_rand_seed & 0xFFFF);
 700   unsigned long hi = a * (long)((unsigned long)_rand_seed >> 16);
 701   lo += (hi & 0x7FFF) << 16;
 702 
 703   // if q overflowed, ignore the overflow and increment q
 704   if (lo > m) {
 705     lo &= m;
 706     ++lo;
 707   }
 708   lo += hi >> 15;
 709 
 710   // if (p+q) overflowed, ignore the overflow and increment (p+q)
 711   if (lo > m) {
 712     lo &= m;
 713     ++lo;
 714   }
 715   return (_rand_seed = lo);
 716 }
 717 
 718 // The INITIALIZED state is distinguished from the SUSPENDED state because the
 719 // conditions in which a thread is first started are different from those in which
 720 // a suspension is resumed.  These differences make it hard for us to apply the
 721 // tougher checks when starting threads that we want to do when resuming them.
 722 // However, when start_thread is called as a result of Thread.start, on a Java
 723 // thread, the operation is synchronized on the Java Thread object.  So there
 724 // cannot be a race to start the thread and hence for the thread to exit while
 725 // we are working on it.  Non-Java threads that start Java threads either have
 726 // to do so in a context in which races are impossible, or should do appropriate
 727 // locking.
 728 
 729 void os::start_thread(Thread* thread) {
 730   // guard suspend/resume
 731   MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
 732   OSThread* osthread = thread->osthread();
 733   osthread->set_state(RUNNABLE);
 734   pd_start_thread(thread);
 735 }
 736 
 737 //---------------------------------------------------------------------------
 738 // Helper functions for fatal error handler
 739 
 740 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
 741   assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
 742 
 743   int cols = 0;
 744   int cols_per_line = 0;
 745   switch (unitsize) {
 746     case 1: cols_per_line = 16; break;
 747     case 2: cols_per_line = 8;  break;
 748     case 4: cols_per_line = 4;  break;
 749     case 8: cols_per_line = 2;  break;
 750     default: return;
 751   }
 752 
 753   address p = start;
 754   st->print(PTR_FORMAT ":   ", start);
 755   while (p < end) {
 756     switch (unitsize) {
 757       case 1: st->print("%02x", *(u1*)p); break;
 758       case 2: st->print("%04x", *(u2*)p); break;
 759       case 4: st->print("%08x", *(u4*)p); break;
 760       case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
 761     }
 762     p += unitsize;
 763     cols++;
 764     if (cols >= cols_per_line && p < end) {
 765        cols = 0;
 766        st->cr();
 767        st->print(PTR_FORMAT ":   ", p);
 768     } else {
 769        st->print(" ");
 770     }
 771   }
 772   st->cr();
 773 }
 774 
 775 void os::print_environment_variables(outputStream* st, const char** env_list,
 776                                      char* buffer, int len) {
 777   if (env_list) {
 778     st->print_cr("Environment Variables:");
 779 
 780     for (int i = 0; env_list[i] != NULL; i++) {
 781       if (getenv(env_list[i], buffer, len)) {
 782         st->print(env_list[i]);
 783         st->print("=");
 784         st->print_cr(buffer);
 785       }
 786     }
 787   }
 788 }
 789 
 790 void os::print_cpu_info(outputStream* st) {
 791   // cpu
 792   st->print("CPU:");
 793   st->print("total %d", os::processor_count());
 794   // It's not safe to query number of active processors after crash
 795   // st->print("(active %d)", os::active_processor_count());
 796   st->print(" %s", VM_Version::cpu_features());
 797   st->cr();
 798   pd_print_cpu_info(st);
 799 }
 800 
 801 void os::print_date_and_time(outputStream *st) {
 802   time_t tloc;
 803   (void)time(&tloc);
 804   st->print("time: %s", ctime(&tloc));  // ctime adds newline.
 805 
 806   double t = os::elapsedTime();
 807   // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
 808   //       Linux. Must be a bug in glibc ? Workaround is to round "t" to int
 809   //       before printf. We lost some precision, but who cares?
 810   st->print_cr("elapsed time: %d seconds", (int)t);
 811 }
 812 
 813 // moved from debug.cpp (used to be find()) but still called from there
 814 // The verbose parameter is only set by the debug code in one case
 815 void os::print_location(outputStream* st, intptr_t x, bool verbose) {
 816   address addr = (address)x;
 817   CodeBlob* b = CodeCache::find_blob_unsafe(addr);
 818   if (b != NULL) {
 819     if (b->is_buffer_blob()) {
 820       // the interpreter is generated into a buffer blob
 821       InterpreterCodelet* i = Interpreter::codelet_containing(addr);
 822       if (i != NULL) {
 823         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an Interpreter codelet", addr, (int)(addr - i->code_begin()));
 824         i->print_on(st);
 825         return;
 826       }
 827       if (Interpreter::contains(addr)) {
 828         st->print_cr(INTPTR_FORMAT " is pointing into interpreter code"
 829                      " (not bytecode specific)", addr);
 830         return;
 831       }
 832       //
 833       if (AdapterHandlerLibrary::contains(b)) {
 834         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an AdapterHandler", addr, (int)(addr - b->code_begin()));
 835         AdapterHandlerLibrary::print_handler_on(st, b);
 836       }
 837       // the stubroutines are generated into a buffer blob
 838       StubCodeDesc* d = StubCodeDesc::desc_for(addr);
 839       if (d != NULL) {
 840         st->print_cr(INTPTR_FORMAT " is at begin+%d in a stub", addr, (int)(addr - d->begin()));
 841         d->print_on(st);
 842         st->cr();
 843         return;
 844       }
 845       if (StubRoutines::contains(addr)) {
 846         st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) "
 847                      "stub routine", addr);
 848         return;
 849       }
 850       // the InlineCacheBuffer is using stubs generated into a buffer blob
 851       if (InlineCacheBuffer::contains(addr)) {
 852         st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", addr);
 853         return;
 854       }
 855       VtableStub* v = VtableStubs::stub_containing(addr);
 856       if (v != NULL) {
 857         st->print_cr(INTPTR_FORMAT " is at entry_point+%d in a vtable stub", addr, (int)(addr - v->entry_point()));
 858         v->print_on(st);
 859         st->cr();
 860         return;
 861       }
 862     }
 863     nmethod* nm = b->as_nmethod_or_null();
 864     if (nm != NULL) {
 865       ResourceMark rm;
 866       st->print(INTPTR_FORMAT " is at entry_point+%d in (nmethod*)" INTPTR_FORMAT,
 867                 addr, (int)(addr - nm->entry_point()), nm);
 868       if (verbose) {
 869         st->print(" for ");
 870         nm->method()->print_value_on(st);
 871       }
 872       st->cr();
 873       nm->print_nmethod(verbose);
 874       return;
 875     }
 876     st->print_cr(INTPTR_FORMAT " is at code_begin+%d in ", addr, (int)(addr - b->code_begin()));
 877     b->print_on(st);
 878     return;
 879   }
 880 
 881   if (Universe::heap()->is_in(addr)) {
 882     HeapWord* p = Universe::heap()->block_start(addr);
 883     bool print = false;
 884     // If we couldn't find it it just may mean that heap wasn't parseable
 885     // See if we were just given an oop directly
 886     if (p != NULL && Universe::heap()->block_is_obj(p)) {
 887       print = true;
 888     } else if (p == NULL && ((oopDesc*)addr)->is_oop()) {
 889       p = (HeapWord*) addr;
 890       print = true;
 891     }
 892     if (print) {
 893       if (p == (HeapWord*) addr) {
 894         st->print_cr(INTPTR_FORMAT " is an oop", addr);
 895       } else {
 896         st->print_cr(INTPTR_FORMAT " is pointing into object: " INTPTR_FORMAT, addr, p);
 897       }
 898       oop(p)->print_on(st);
 899       if (p != (HeapWord*)x && oop(p)->is_constMethod() &&
 900           constMethodOop(p)->contains(addr)) {
 901         Thread *thread = Thread::current();
 902         HandleMark hm(thread);
 903         methodHandle mh (thread, constMethodOop(p)->method());
 904         if (!mh->is_native()) {
 905           st->print_cr("bci_from(%p) = %d; print_codes():",
 906                         addr, mh->bci_from(address(x)));
 907           mh->print_codes_on(st);
 908         }
 909       }
 910       return;
 911     }
 912   } else {
 913     if (Universe::heap()->is_in_reserved(addr)) {
 914       st->print_cr(INTPTR_FORMAT " is an unallocated location "
 915                    "in the heap", addr);
 916       return;
 917     }
 918   }
 919   if (JNIHandles::is_global_handle((jobject) addr)) {
 920     st->print_cr(INTPTR_FORMAT " is a global jni handle", addr);
 921     return;
 922   }
 923   if (JNIHandles::is_weak_global_handle((jobject) addr)) {
 924     st->print_cr(INTPTR_FORMAT " is a weak global jni handle", addr);
 925     return;
 926   }
 927 #ifndef PRODUCT
 928   // we don't keep the block list in product mode
 929   if (JNIHandleBlock::any_contains((jobject) addr)) {
 930     st->print_cr(INTPTR_FORMAT " is a local jni handle", addr);
 931     return;
 932   }
 933 #endif
 934 
 935   for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
 936     // Check for privilege stack
 937     if (thread->privileged_stack_top() != NULL &&
 938         thread->privileged_stack_top()->contains(addr)) {
 939       st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack "
 940                    "for thread: " INTPTR_FORMAT, addr, thread);
 941       if (verbose) thread->print_on(st);
 942       return;
 943     }
 944     // If the addr is a java thread print information about that.
 945     if (addr == (address)thread) {
 946       if (verbose) {
 947         thread->print_on(st);
 948       } else {
 949         st->print_cr(INTPTR_FORMAT " is a thread", addr);
 950       }
 951       return;
 952     }
 953     // If the addr is in the stack region for this thread then report that
 954     // and print thread info
 955     if (thread->stack_base() >= addr &&
 956         addr > (thread->stack_base() - thread->stack_size())) {
 957       st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
 958                    INTPTR_FORMAT, addr, thread);
 959       if (verbose) thread->print_on(st);
 960       return;
 961     }
 962 
 963   }
 964   // Try an OS specific find
 965   if (os::find(addr, st)) {
 966     return;
 967   }
 968 
 969   st->print_cr(INTPTR_FORMAT " is an unknown value", addr);
 970 }
 971 
 972 // Looks like all platforms except IA64 can use the same function to check
 973 // if C stack is walkable beyond current frame. The check for fp() is not
 974 // necessary on Sparc, but it's harmless.
 975 bool os::is_first_C_frame(frame* fr) {
 976 #ifdef IA64
 977   // In order to walk native frames on Itanium, we need to access the unwind
 978   // table, which is inside ELF. We don't want to parse ELF after fatal error,
 979   // so return true for IA64. If we need to support C stack walking on IA64,
 980   // this function needs to be moved to CPU specific files, as fp() on IA64
 981   // is register stack, which grows towards higher memory address.
 982   return true;
 983 #endif
 984 
 985   // Load up sp, fp, sender sp and sender fp, check for reasonable values.
 986   // Check usp first, because if that's bad the other accessors may fault
 987   // on some architectures.  Ditto ufp second, etc.
 988   uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
 989   // sp on amd can be 32 bit aligned.
 990   uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
 991 
 992   uintptr_t usp    = (uintptr_t)fr->sp();
 993   if ((usp & sp_align_mask) != 0) return true;
 994 
 995   uintptr_t ufp    = (uintptr_t)fr->fp();
 996   if ((ufp & fp_align_mask) != 0) return true;
 997 
 998   uintptr_t old_sp = (uintptr_t)fr->sender_sp();
 999   if ((old_sp & sp_align_mask) != 0) return true;
1000   if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
1001 
1002   uintptr_t old_fp = (uintptr_t)fr->link();
1003   if ((old_fp & fp_align_mask) != 0) return true;
1004   if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
1005 
1006   // stack grows downwards; if old_fp is below current fp or if the stack
1007   // frame is too large, either the stack is corrupted or fp is not saved
1008   // on stack (i.e. on x86, ebp may be used as general register). The stack
1009   // is not walkable beyond current frame.
1010   if (old_fp < ufp) return true;
1011   if (old_fp - ufp > 64 * K) return true;
1012 
1013   return false;
1014 }
1015 
1016 #ifdef ASSERT
1017 extern "C" void test_random() {
1018   const double m = 2147483647;
1019   double mean = 0.0, variance = 0.0, t;
1020   long reps = 10000;
1021   unsigned long seed = 1;
1022 
1023   tty->print_cr("seed %ld for %ld repeats...", seed, reps);
1024   os::init_random(seed);
1025   long num;
1026   for (int k = 0; k < reps; k++) {
1027     num = os::random();
1028     double u = (double)num / m;
1029     assert(u >= 0.0 && u <= 1.0, "bad random number!");
1030 
1031     // calculate mean and variance of the random sequence
1032     mean += u;
1033     variance += (u*u);
1034   }
1035   mean /= reps;
1036   variance /= (reps - 1);
1037 
1038   assert(num == 1043618065, "bad seed");
1039   tty->print_cr("mean of the 1st 10000 numbers: %f", mean);
1040   tty->print_cr("variance of the 1st 10000 numbers: %f", variance);
1041   const double eps = 0.0001;
1042   t = fabsd(mean - 0.5018);
1043   assert(t < eps, "bad mean");
1044   t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355;
1045   assert(t < eps, "bad variance");
1046 }
1047 #endif
1048 
1049 
1050 // Set up the boot classpath.
1051 
1052 char* os::format_boot_path(const char* format_string,
1053                            const char* home,
1054                            int home_len,
1055                            char fileSep,
1056                            char pathSep) {
1057     assert((fileSep == '/' && pathSep == ':') ||
1058            (fileSep == '\\' && pathSep == ';'), "unexpected seperator chars");
1059 
1060     // Scan the format string to determine the length of the actual
1061     // boot classpath, and handle platform dependencies as well.
1062     int formatted_path_len = 0;
1063     const char* p;
1064     for (p = format_string; *p != 0; ++p) {
1065         if (*p == '%') formatted_path_len += home_len - 1;
1066         ++formatted_path_len;
1067     }
1068 
1069     char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal);
1070     if (formatted_path == NULL) {
1071         return NULL;
1072     }
1073 
1074     // Create boot classpath from format, substituting separator chars and
1075     // java home directory.
1076     char* q = formatted_path;
1077     for (p = format_string; *p != 0; ++p) {
1078         switch (*p) {
1079         case '%':
1080             strcpy(q, home);
1081             q += home_len;
1082             break;
1083         case '/':
1084             *q++ = fileSep;
1085             break;
1086         case ':':
1087             *q++ = pathSep;
1088             break;
1089         default:
1090             *q++ = *p;
1091         }
1092     }
1093     *q = '\0';
1094 
1095     assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
1096     return formatted_path;
1097 }
1098 
1099 
1100 bool os::set_boot_path(char fileSep, char pathSep) {
1101     const char* home = Arguments::get_java_home();
1102     int home_len = (int)strlen(home);
1103 
1104     static const char* meta_index_dir_format = "%/lib/";
1105     static const char* meta_index_format = "%/lib/meta-index";
1106     char* meta_index = format_boot_path(meta_index_format, home, home_len, fileSep, pathSep);
1107     if (meta_index == NULL) return false;
1108     char* meta_index_dir = format_boot_path(meta_index_dir_format, home, home_len, fileSep, pathSep);
1109     if (meta_index_dir == NULL) return false;
1110     Arguments::set_meta_index_path(meta_index, meta_index_dir);
1111 
1112     // Any modification to the JAR-file list, for the boot classpath must be
1113     // aligned with install/install/make/common/Pack.gmk. Note: boot class
1114     // path class JARs, are stripped for StackMapTable to reduce download size.
1115     static const char classpath_format[] =
1116         "%/lib/resources.jar:"
1117         "%/lib/rt.jar:"
1118         "%/lib/sunrsasign.jar:"
1119         "%/lib/jsse.jar:"
1120         "%/lib/jce.jar:"
1121         "%/lib/charsets.jar:"
1122         "%/lib/jfr.jar:"
1123 #ifdef __APPLE__
1124         "%/lib/JObjC.jar:"
1125 #endif
1126         "%/classes";
1127     char* sysclasspath = format_boot_path(classpath_format, home, home_len, fileSep, pathSep);
1128     if (sysclasspath == NULL) return false;
1129     Arguments::set_sysclasspath(sysclasspath);
1130 
1131     return true;
1132 }
1133 
1134 /*
1135  * Splits a path, based on its separator, the number of
1136  * elements is returned back in n.
1137  * It is the callers responsibility to:
1138  *   a> check the value of n, and n may be 0.
1139  *   b> ignore any empty path elements
1140  *   c> free up the data.
1141  */
1142 char** os::split_path(const char* path, int* n) {
1143   *n = 0;
1144   if (path == NULL || strlen(path) == 0) {
1145     return NULL;
1146   }
1147   const char psepchar = *os::path_separator();
1148   char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal);
1149   if (inpath == NULL) {
1150     return NULL;
1151   }
1152   strncpy(inpath, path, strlen(path));
1153   int count = 1;
1154   char* p = strchr(inpath, psepchar);
1155   // Get a count of elements to allocate memory
1156   while (p != NULL) {
1157     count++;
1158     p++;
1159     p = strchr(p, psepchar);
1160   }
1161   char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count, mtInternal);
1162   if (opath == NULL) {
1163     return NULL;
1164   }
1165 
1166   // do the actual splitting
1167   p = inpath;
1168   for (int i = 0 ; i < count ; i++) {
1169     size_t len = strcspn(p, os::path_separator());
1170     if (len > JVM_MAXPATHLEN) {
1171       return NULL;
1172     }
1173     // allocate the string and add terminator storage
1174     char* s  = (char*)NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
1175     if (s == NULL) {
1176       return NULL;
1177     }
1178     strncpy(s, p, len);
1179     s[len] = '\0';
1180     opath[i] = s;
1181     p += len + 1;
1182   }
1183   FREE_C_HEAP_ARRAY(char, inpath, mtInternal);
1184   *n = count;
1185   return opath;
1186 }
1187 
1188 void os::set_memory_serialize_page(address page) {
1189   int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64);
1190   _mem_serialize_page = (volatile int32_t *)page;
1191   // We initialize the serialization page shift count here
1192   // We assume a cache line size of 64 bytes
1193   assert(SerializePageShiftCount == count,
1194          "thread size changed, fix SerializePageShiftCount constant");
1195   set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t)));
1196 }
1197 
1198 static volatile intptr_t SerializePageLock = 0;
1199 
1200 // This method is called from signal handler when SIGSEGV occurs while the current
1201 // thread tries to store to the "read-only" memory serialize page during state
1202 // transition.
1203 void os::block_on_serialize_page_trap() {
1204   if (TraceSafepoint) {
1205     tty->print_cr("Block until the serialize page permission restored");
1206   }
1207   // When VMThread is holding the SerializePageLock during modifying the
1208   // access permission of the memory serialize page, the following call
1209   // will block until the permission of that page is restored to rw.
1210   // Generally, it is unsafe to manipulate locks in signal handlers, but in
1211   // this case, it's OK as the signal is synchronous and we know precisely when
1212   // it can occur.
1213   Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page");
1214   Thread::muxRelease(&SerializePageLock);
1215 }
1216 
1217 // Serialize all thread state variables
1218 void os::serialize_thread_states() {
1219   // On some platforms such as Solaris & Linux, the time duration of the page
1220   // permission restoration is observed to be much longer than expected  due to
1221   // scheduler starvation problem etc. To avoid the long synchronization
1222   // time and expensive page trap spinning, 'SerializePageLock' is used to block
1223   // the mutator thread if such case is encountered. See bug 6546278 for details.
1224   Thread::muxAcquire(&SerializePageLock, "serialize_thread_states");
1225   os::protect_memory((char *)os::get_memory_serialize_page(),
1226                      os::vm_page_size(), MEM_PROT_READ);
1227   os::protect_memory((char *)os::get_memory_serialize_page(),
1228                      os::vm_page_size(), MEM_PROT_RW);
1229   Thread::muxRelease(&SerializePageLock);
1230 }
1231 
1232 // Returns true if the current stack pointer is above the stack shadow
1233 // pages, false otherwise.
1234 
1235 bool os::stack_shadow_pages_available(Thread *thread, methodHandle method) {
1236   assert(StackRedPages > 0 && StackYellowPages > 0,"Sanity check");
1237   address sp = current_stack_pointer();
1238   // Check if we have StackShadowPages above the yellow zone.  This parameter
1239   // is dependent on the depth of the maximum VM call stack possible from
1240   // the handler for stack overflow.  'instanceof' in the stack overflow
1241   // handler or a println uses at least 8k stack of VM and native code
1242   // respectively.
1243   const int framesize_in_bytes =
1244     Interpreter::size_top_interpreter_activation(method()) * wordSize;
1245   int reserved_area = ((StackShadowPages + StackRedPages + StackYellowPages)
1246                       * vm_page_size()) + framesize_in_bytes;
1247   // The very lower end of the stack
1248   address stack_limit = thread->stack_base() - thread->stack_size();
1249   return (sp > (stack_limit + reserved_area));
1250 }
1251 
1252 size_t os::page_size_for_region(size_t region_min_size, size_t region_max_size,
1253                                 uint min_pages)
1254 {
1255   assert(min_pages > 0, "sanity");
1256   if (UseLargePages) {
1257     const size_t max_page_size = region_max_size / min_pages;
1258 
1259     for (unsigned int i = 0; _page_sizes[i] != 0; ++i) {
1260       const size_t sz = _page_sizes[i];
1261       const size_t mask = sz - 1;
1262       if ((region_min_size & mask) == 0 && (region_max_size & mask) == 0) {
1263         // The largest page size with no fragmentation.
1264         return sz;
1265       }
1266 
1267       if (sz <= max_page_size) {
1268         // The largest page size that satisfies the min_pages requirement.
1269         return sz;
1270       }
1271     }
1272   }
1273 
1274   return vm_page_size();
1275 }
1276 
1277 #ifndef PRODUCT
1278 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count)
1279 {
1280   if (TracePageSizes) {
1281     tty->print("%s: ", str);
1282     for (int i = 0; i < count; ++i) {
1283       tty->print(" " SIZE_FORMAT, page_sizes[i]);
1284     }
1285     tty->cr();
1286   }
1287 }
1288 
1289 void os::trace_page_sizes(const char* str, const size_t region_min_size,
1290                           const size_t region_max_size, const size_t page_size,
1291                           const char* base, const size_t size)
1292 {
1293   if (TracePageSizes) {
1294     tty->print_cr("%s:  min=" SIZE_FORMAT " max=" SIZE_FORMAT
1295                   " pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT
1296                   " size=" SIZE_FORMAT,
1297                   str, region_min_size, region_max_size,
1298                   page_size, base, size);
1299   }
1300 }
1301 #endif  // #ifndef PRODUCT
1302 
1303 // This is the working definition of a server class machine:
1304 // >= 2 physical CPU's and >=2GB of memory, with some fuzz
1305 // because the graphics memory (?) sometimes masks physical memory.
1306 // If you want to change the definition of a server class machine
1307 // on some OS or platform, e.g., >=4GB on Windohs platforms,
1308 // then you'll have to parameterize this method based on that state,
1309 // as was done for logical processors here, or replicate and
1310 // specialize this method for each platform.  (Or fix os to have
1311 // some inheritance structure and use subclassing.  Sigh.)
1312 // If you want some platform to always or never behave as a server
1313 // class machine, change the setting of AlwaysActAsServerClassMachine
1314 // and NeverActAsServerClassMachine in globals*.hpp.
1315 bool os::is_server_class_machine() {
1316   // First check for the early returns
1317   if (NeverActAsServerClassMachine) {
1318     return false;
1319   }
1320   if (AlwaysActAsServerClassMachine) {
1321     return true;
1322   }
1323   // Then actually look at the machine
1324   bool         result            = false;
1325   const unsigned int    server_processors = 2;
1326   const julong server_memory     = 2UL * G;
1327   // We seem not to get our full complement of memory.
1328   //     We allow some part (1/8?) of the memory to be "missing",
1329   //     based on the sizes of DIMMs, and maybe graphics cards.
1330   const julong missing_memory   = 256UL * M;
1331 
1332   /* Is this a server class machine? */
1333   if ((os::active_processor_count() >= (int)server_processors) &&
1334       (os::physical_memory() >= (server_memory - missing_memory))) {
1335     const unsigned int logical_processors =
1336       VM_Version::logical_processors_per_package();
1337     if (logical_processors > 1) {
1338       const unsigned int physical_packages =
1339         os::active_processor_count() / logical_processors;
1340       if (physical_packages > server_processors) {
1341         result = true;
1342       }
1343     } else {
1344       result = true;
1345     }
1346   }
1347   return result;
1348 }
1349 
1350 // Read file line by line, if line is longer than bsize,
1351 // skip rest of line.
1352 int os::get_line_chars(int fd, char* buf, const size_t bsize){
1353   size_t sz, i = 0;
1354 
1355   // read until EOF, EOL or buf is full
1356   while ((sz = (int) read(fd, &buf[i], 1)) == 1 && i < (bsize-2) && buf[i] != '\n') {
1357      ++i;
1358   }
1359 
1360   if (buf[i] == '\n') {
1361     // EOL reached so ignore EOL character and return
1362 
1363     buf[i] = 0;
1364     return (int) i;
1365   }
1366 
1367   buf[i+1] = 0;
1368 
1369   if (sz != 1) {
1370     // EOF reached. if we read chars before EOF return them and
1371     // return EOF on next call otherwise return EOF
1372 
1373     return (i == 0) ? -1 : (int) i;
1374   }
1375 
1376   // line is longer than size of buf, skip to EOL
1377   char ch;
1378   while (read(fd, &ch, 1) == 1 && ch != '\n') {
1379     // Do nothing
1380   }
1381 
1382   // return initial part of line that fits in buf.
1383   // If we reached EOF, it will be returned on next call.
1384 
1385   return (int) i;
1386 }
1387 
1388 void os::SuspendedThreadTask::run() {
1389   assert(Threads_lock->owned_by_self() || (_thread == VMThread::vm_thread()), "must have threads lock to call this");
1390   internal_do_task();
1391   _done = true;
1392 }
1393 
1394 bool os::create_stack_guard_pages(char* addr, size_t bytes) {
1395   return os::pd_create_stack_guard_pages(addr, bytes);
1396 }
1397 
1398 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint) {
1399   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1400   if (result != NULL) {
1401     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1402   }
1403 
1404   return result;
1405 }
1406 char* os::attempt_reserve_memory_at(size_t bytes, char* addr) {
1407   char* result = pd_attempt_reserve_memory_at(bytes, addr);
1408   if (result != NULL) {
1409     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1410   }
1411   return result;
1412 }
1413 
1414 void os::split_reserved_memory(char *base, size_t size,
1415                                  size_t split, bool realloc) {
1416   pd_split_reserved_memory(base, size, split, realloc);
1417 }
1418 
1419 bool os::commit_memory(char* addr, size_t bytes, bool executable) {
1420   bool res = pd_commit_memory(addr, bytes, executable);
1421   if (res) {
1422     MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1423   }
1424   return res;
1425 }
1426 
1427 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
1428                               bool executable) {
1429   bool res = os::pd_commit_memory(addr, size, alignment_hint, executable);
1430   if (res) {
1431     MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1432   }
1433   return res;
1434 }
1435 
1436 bool os::uncommit_memory(char* addr, size_t bytes) {
1437   bool res = pd_uncommit_memory(addr, bytes);
1438   if (res) {
1439     MemTracker::record_virtual_memory_uncommit((address)addr, bytes);
1440   }
1441   return res;
1442 }
1443 
1444 bool os::release_memory(char* addr, size_t bytes) {
1445   bool res = pd_release_memory(addr, bytes);
1446   if (res) {
1447     MemTracker::record_virtual_memory_release((address)addr, bytes);
1448   }
1449   return res;
1450 }
1451 
1452 
1453 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
1454                            char *addr, size_t bytes, bool read_only,
1455                            bool allow_exec) {
1456   char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec);
1457   if (result != NULL) {
1458     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1459     MemTracker::record_virtual_memory_commit((address)result, bytes, CALLER_PC);
1460   }
1461   return result;
1462 }
1463 
1464 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
1465                              char *addr, size_t bytes, bool read_only,
1466                              bool allow_exec) {
1467   return pd_remap_memory(fd, file_name, file_offset, addr, bytes,
1468                     read_only, allow_exec);
1469 }
1470 
1471 bool os::unmap_memory(char *addr, size_t bytes) {
1472   bool result = pd_unmap_memory(addr, bytes);
1473   if (result) {
1474     MemTracker::record_virtual_memory_uncommit((address)addr, bytes);
1475     MemTracker::record_virtual_memory_release((address)addr, bytes);
1476   }
1477   return result;
1478 }
1479 
1480 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
1481   pd_free_memory(addr, bytes, alignment_hint);
1482 }
1483 
1484 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
1485   pd_realign_memory(addr, bytes, alignment_hint);
1486 }
1487