1 /*
   2  * Copyright (c) 1997, 2014, 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 #ifndef SHARE_VM_RUNTIME_OS_HPP
  26 #define SHARE_VM_RUNTIME_OS_HPP
  27 
  28 #include "jvmtifiles/jvmti.h"
  29 #include "runtime/extendedPC.hpp"
  30 #include "runtime/handles.hpp"
  31 #include "utilities/top.hpp"
  32 #ifdef TARGET_OS_FAMILY_linux
  33 # include "jvm_linux.h"
  34 # include <setjmp.h>
  35 #endif
  36 #ifdef TARGET_OS_FAMILY_solaris
  37 # include "jvm_solaris.h"
  38 # include <setjmp.h>
  39 #endif
  40 #ifdef TARGET_OS_FAMILY_windows
  41 # include "jvm_windows.h"
  42 #endif
  43 #ifdef TARGET_OS_FAMILY_aix
  44 # include "jvm_aix.h"
  45 # include <setjmp.h>
  46 #endif
  47 #ifdef TARGET_OS_FAMILY_bsd
  48 # include "jvm_bsd.h"
  49 # include <setjmp.h>
  50 # ifdef __APPLE__
  51 #  include <mach/mach_time.h>
  52 # endif
  53 #endif
  54 
  55 class AgentLibrary;
  56 
  57 // os defines the interface to operating system; this includes traditional
  58 // OS services (time, I/O) as well as other functionality with system-
  59 // dependent code.
  60 
  61 typedef void (*dll_func)(...);
  62 
  63 class Thread;
  64 class JavaThread;
  65 class Event;
  66 class DLL;
  67 class FileHandle;
  68 class NativeCallStack;
  69 
  70 template<class E> class GrowableArray;
  71 
  72 // %%%%% Moved ThreadState, START_FN, OSThread to new osThread.hpp. -- Rose
  73 
  74 // Platform-independent error return values from OS functions
  75 enum OSReturn {
  76   OS_OK         =  0,        // Operation was successful
  77   OS_ERR        = -1,        // Operation failed
  78   OS_INTRPT     = -2,        // Operation was interrupted
  79   OS_TIMEOUT    = -3,        // Operation timed out
  80   OS_NOMEM      = -5,        // Operation failed for lack of memory
  81   OS_NORESOURCE = -6         // Operation failed for lack of nonmemory resource
  82 };
  83 
  84 enum ThreadPriority {        // JLS 20.20.1-3
  85   NoPriority       = -1,     // Initial non-priority value
  86   MinPriority      =  1,     // Minimum priority
  87   NormPriority     =  5,     // Normal (non-daemon) priority
  88   NearMaxPriority  =  9,     // High priority, used for VMThread
  89   MaxPriority      = 10,     // Highest priority, used for WatcherThread
  90                              // ensures that VMThread doesn't starve profiler
  91   CriticalPriority = 11      // Critical thread priority
  92 };
  93 
  94 // Executable parameter flag for os::commit_memory() and
  95 // os::commit_memory_or_exit().
  96 const bool ExecMem = true;
  97 
  98 // Typedef for structured exception handling support
  99 typedef void (*java_call_t)(JavaValue* value, methodHandle* method, JavaCallArguments* args, Thread* thread);
 100 
 101 class MallocTracker;
 102 
 103 class os: AllStatic {
 104   friend class VMStructs;
 105   friend class MallocTracker;
 106  public:
 107   enum { page_sizes_max = 9 }; // Size of _page_sizes array (8 plus a sentinel)
 108 
 109  private:
 110   static OSThread*          _starting_thread;
 111   static address            _polling_page;
 112   static volatile int32_t * _mem_serialize_page;
 113   static uintptr_t          _serialize_page_mask;
 114  public:
 115   static size_t             _page_sizes[page_sizes_max];
 116 
 117  private:
 118   static void init_page_sizes(size_t default_page_size) {
 119     _page_sizes[0] = default_page_size;
 120     _page_sizes[1] = 0; // sentinel
 121   }
 122 
 123   static char*  pd_reserve_memory(size_t bytes, char* addr = 0,
 124                                size_t alignment_hint = 0);
 125   static char*  pd_attempt_reserve_memory_at(size_t bytes, char* addr);
 126   static void   pd_split_reserved_memory(char *base, size_t size,
 127                                       size_t split, bool realloc);
 128   static bool   pd_commit_memory(char* addr, size_t bytes, bool executable);
 129   static bool   pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
 130                                  bool executable);
 131   // Same as pd_commit_memory() that either succeeds or calls
 132   // vm_exit_out_of_memory() with the specified mesg.
 133   static void   pd_commit_memory_or_exit(char* addr, size_t bytes,
 134                                          bool executable, const char* mesg);
 135   static void   pd_commit_memory_or_exit(char* addr, size_t size,
 136                                          size_t alignment_hint,
 137                                          bool executable, const char* mesg);
 138   static bool   pd_uncommit_memory(char* addr, size_t bytes);
 139   static bool   pd_release_memory(char* addr, size_t bytes);
 140 
 141   static char*  pd_map_memory(int fd, const char* file_name, size_t file_offset,
 142                            char *addr, size_t bytes, bool read_only = false,
 143                            bool allow_exec = false);
 144   static char*  pd_remap_memory(int fd, const char* file_name, size_t file_offset,
 145                              char *addr, size_t bytes, bool read_only,
 146                              bool allow_exec);
 147   static bool   pd_unmap_memory(char *addr, size_t bytes);
 148   static void   pd_free_memory(char *addr, size_t bytes, size_t alignment_hint);
 149   static void   pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint);
 150 
 151 
 152  public:
 153   static void init(void);                      // Called before command line parsing
 154   static void init_before_ergo(void);          // Called after command line parsing
 155                                                // before VM ergonomics processing.
 156   static jint init_2(void);                    // Called after command line parsing
 157                                                // and VM ergonomics processing
 158   static void init_globals(void) {             // Called from init_globals() in init.cpp
 159     init_globals_ext();
 160   }
 161   static void init_3(void);                    // Called at the end of vm init
 162 
 163   // File names are case-insensitive on windows only
 164   // Override me as needed
 165   static int    file_name_strcmp(const char* s1, const char* s2);
 166 
 167   // get/unset environment variable
 168   static bool getenv(const char* name, char* buffer, int len);
 169   static bool unsetenv(const char* name);
 170 
 171   static bool have_special_privileges();
 172 
 173   static jlong  javaTimeMillis();
 174   static jlong  javaTimeNanos();
 175   static void   javaTimeNanos_info(jvmtiTimerInfo *info_ptr);
 176   static void   run_periodic_checks();
 177   static bool   supports_monotonic_clock();
 178 
 179 
 180   // Returns the elapsed time in seconds since the vm started.
 181   static double elapsedTime();
 182 
 183   // Returns real time in seconds since an arbitrary point
 184   // in the past.
 185   static bool getTimesSecs(double* process_real_time,
 186                            double* process_user_time,
 187                            double* process_system_time);
 188 
 189   // Interface to the performance counter
 190   static jlong elapsed_counter();
 191   static jlong elapsed_frequency();
 192 
 193   // The "virtual time" of a thread is the amount of time a thread has
 194   // actually run.  The first function indicates whether the OS supports
 195   // this functionality for the current thread, and if so:
 196   //   * the second enables vtime tracking (if that is required).
 197   //   * the third tells whether vtime is enabled.
 198   //   * the fourth returns the elapsed virtual time for the current
 199   //     thread.
 200   static bool supports_vtime();
 201   static bool enable_vtime();
 202   static bool vtime_enabled();
 203   static double elapsedVTime();
 204 
 205   // Return current local time in a string (YYYY-MM-DD HH:MM:SS).
 206   // It is MT safe, but not async-safe, as reading time zone
 207   // information may require a lock on some platforms.
 208   static char*      local_time_string(char *buf, size_t buflen);
 209   static struct tm* localtime_pd     (const time_t* clock, struct tm*  res);
 210   // Fill in buffer with current local time as an ISO-8601 string.
 211   // E.g., YYYY-MM-DDThh:mm:ss.mmm+zzzz.
 212   // Returns buffer, or NULL if it failed.
 213   static char* iso8601_time(char* buffer, size_t buffer_length);
 214 
 215   // Interface for detecting multiprocessor system
 216   static inline bool is_MP() {
 217 #if !INCLUDE_NMT
 218     assert(_processor_count > 0, "invalid processor count");
 219     return _processor_count > 1 || AssumeMP;
 220 #else
 221     // NMT needs atomic operations before this initialization.
 222     return true;
 223 #endif
 224   }
 225   static julong available_memory();
 226   static julong physical_memory();
 227   static bool has_allocatable_memory_limit(julong* limit);
 228   static bool is_server_class_machine();
 229 
 230   // number of CPUs
 231   static int processor_count() {
 232     return _processor_count;
 233   }
 234   static void set_processor_count(int count) { _processor_count = count; }
 235 
 236   // Returns the number of CPUs this process is currently allowed to run on.
 237   // Note that on some OSes this can change dynamically.
 238   static int active_processor_count();
 239 
 240   // Bind processes to processors.
 241   //     This is a two step procedure:
 242   //     first you generate a distribution of processes to processors,
 243   //     then you bind processes according to that distribution.
 244   // Compute a distribution for number of processes to processors.
 245   //    Stores the processor id's into the distribution array argument.
 246   //    Returns true if it worked, false if it didn't.
 247   static bool distribute_processes(uint length, uint* distribution);
 248   // Binds the current process to a processor.
 249   //    Returns true if it worked, false if it didn't.
 250   static bool bind_to_processor(uint processor_id);
 251 
 252   // Give a name to the current thread.
 253   static void set_native_thread_name(const char *name);
 254 
 255   // Interface for stack banging (predetect possible stack overflow for
 256   // exception processing)  There are guard pages, and above that shadow
 257   // pages for stack overflow checking.
 258   static bool uses_stack_guard_pages();
 259   static bool allocate_stack_guard_pages();
 260   static void bang_stack_shadow_pages();
 261   static bool stack_shadow_pages_available(Thread *thread, methodHandle method);
 262 
 263   // OS interface to Virtual Memory
 264 
 265   // Return the default page size.
 266   static int    vm_page_size();
 267 
 268   // Return the page size to use for a region of memory.  The min_pages argument
 269   // is a hint intended to limit fragmentation; it says the returned page size
 270   // should be <= region_max_size / min_pages.  Because min_pages is a hint,
 271   // this routine may return a size larger than region_max_size / min_pages.
 272   //
 273   // The current implementation ignores min_pages if a larger page size is an
 274   // exact multiple of both region_min_size and region_max_size.  This allows
 275   // larger pages to be used when doing so would not cause fragmentation; in
 276   // particular, a single page can be used when region_min_size ==
 277   // region_max_size == a supported page size.
 278   static size_t page_size_for_region(size_t region_min_size,
 279                                      size_t region_max_size,
 280                                      uint min_pages);
 281   // Return the largest page size that can be used
 282   static size_t max_page_size() {
 283     // The _page_sizes array is sorted in descending order.
 284     return _page_sizes[0];
 285   }
 286 
 287   // Methods for tracing page sizes returned by the above method; enabled by
 288   // TracePageSizes.  The region_{min,max}_size parameters should be the values
 289   // passed to page_size_for_region() and page_size should be the result of that
 290   // call.  The (optional) base and size parameters should come from the
 291   // ReservedSpace base() and size() methods.
 292   static void trace_page_sizes(const char* str, const size_t* page_sizes,
 293                                int count) PRODUCT_RETURN;
 294   static void trace_page_sizes(const char* str, const size_t region_min_size,
 295                                const size_t region_max_size,
 296                                const size_t page_size,
 297                                const char* base = NULL,
 298                                const size_t size = 0) PRODUCT_RETURN;
 299 
 300   static int    vm_allocation_granularity();
 301   static char*  reserve_memory(size_t bytes, char* addr = 0,
 302                                size_t alignment_hint = 0);
 303   static char*  reserve_memory(size_t bytes, char* addr,
 304                                size_t alignment_hint, MEMFLAGS flags);
 305   static char*  reserve_memory_aligned(size_t size, size_t alignment);
 306   static char*  attempt_reserve_memory_at(size_t bytes, char* addr);
 307   static void   split_reserved_memory(char *base, size_t size,
 308                                       size_t split, bool realloc);
 309   static bool   commit_memory(char* addr, size_t bytes, bool executable);
 310   static bool   commit_memory(char* addr, size_t size, size_t alignment_hint,
 311                               bool executable);
 312   // Same as commit_memory() that either succeeds or calls
 313   // vm_exit_out_of_memory() with the specified mesg.
 314   static void   commit_memory_or_exit(char* addr, size_t bytes,
 315                                       bool executable, const char* mesg);
 316   static void   commit_memory_or_exit(char* addr, size_t size,
 317                                       size_t alignment_hint,
 318                                       bool executable, const char* mesg);
 319   static bool   uncommit_memory(char* addr, size_t bytes);
 320   static bool   release_memory(char* addr, size_t bytes);
 321 
 322   enum ProtType { MEM_PROT_NONE, MEM_PROT_READ, MEM_PROT_RW, MEM_PROT_RWX };
 323   static bool   protect_memory(char* addr, size_t bytes, ProtType prot,
 324                                bool is_committed = true);
 325 
 326   static bool   guard_memory(char* addr, size_t bytes);
 327   static bool   unguard_memory(char* addr, size_t bytes);
 328   static bool   create_stack_guard_pages(char* addr, size_t bytes);
 329   static bool   pd_create_stack_guard_pages(char* addr, size_t bytes);
 330   static bool   remove_stack_guard_pages(char* addr, size_t bytes);
 331 
 332   static char*  map_memory(int fd, const char* file_name, size_t file_offset,
 333                            char *addr, size_t bytes, bool read_only = false,
 334                            bool allow_exec = false);
 335   static char*  remap_memory(int fd, const char* file_name, size_t file_offset,
 336                              char *addr, size_t bytes, bool read_only,
 337                              bool allow_exec);
 338   static bool   unmap_memory(char *addr, size_t bytes);
 339   static void   free_memory(char *addr, size_t bytes, size_t alignment_hint);
 340   static void   realign_memory(char *addr, size_t bytes, size_t alignment_hint);
 341 
 342   // NUMA-specific interface
 343   static bool   numa_has_static_binding();
 344   static bool   numa_has_group_homing();
 345   static void   numa_make_local(char *addr, size_t bytes, int lgrp_hint);
 346   static void   numa_make_global(char *addr, size_t bytes);
 347   static size_t numa_get_groups_num();
 348   static size_t numa_get_leaf_groups(int *ids, size_t size);
 349   static bool   numa_topology_changed();
 350   static int    numa_get_group_id();
 351 
 352   // Page manipulation
 353   struct page_info {
 354     size_t size;
 355     int lgrp_id;
 356   };
 357   static bool   get_page_info(char *start, page_info* info);
 358   static char*  scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found);
 359 
 360   static char*  non_memory_address_word();
 361   // reserve, commit and pin the entire memory region
 362   static char*  reserve_memory_special(size_t size, size_t alignment,
 363                                        char* addr, bool executable);
 364   static bool   release_memory_special(char* addr, size_t bytes);
 365   static void   large_page_init();
 366   static size_t large_page_size();
 367   static bool   can_commit_large_page_memory();
 368   static bool   can_execute_large_page_memory();
 369 
 370   // OS interface to polling page
 371   static address get_polling_page()             { return _polling_page; }
 372   static void    set_polling_page(address page) { _polling_page = page; }
 373   static bool    is_poll_address(address addr)  { return addr >= _polling_page && addr < (_polling_page + os::vm_page_size()); }
 374   static void    make_polling_page_unreadable();
 375   static void    make_polling_page_readable();
 376 
 377   // Routines used to serialize the thread state without using membars
 378   static void    serialize_thread_states();
 379 
 380   // Since we write to the serialize page from every thread, we
 381   // want stores to be on unique cache lines whenever possible
 382   // in order to minimize CPU cross talk.  We pre-compute the
 383   // amount to shift the thread* to make this offset unique to
 384   // each thread.
 385   static int     get_serialize_page_shift_count() {
 386     return SerializePageShiftCount;
 387   }
 388 
 389   static void     set_serialize_page_mask(uintptr_t mask) {
 390     _serialize_page_mask = mask;
 391   }
 392 
 393   static unsigned int  get_serialize_page_mask() {
 394     return _serialize_page_mask;
 395   }
 396 
 397   static void    set_memory_serialize_page(address page);
 398 
 399   static address get_memory_serialize_page() {
 400     return (address)_mem_serialize_page;
 401   }
 402 
 403   static inline void write_memory_serialize_page(JavaThread *thread) {
 404     uintptr_t page_offset = ((uintptr_t)thread >>
 405                             get_serialize_page_shift_count()) &
 406                             get_serialize_page_mask();
 407     *(volatile int32_t *)((uintptr_t)_mem_serialize_page+page_offset) = 1;
 408   }
 409 
 410   static bool    is_memory_serialize_page(JavaThread *thread, address addr) {
 411     if (UseMembar) return false;
 412     // Previously this function calculated the exact address of this
 413     // thread's serialize page, and checked if the faulting address
 414     // was equal.  However, some platforms mask off faulting addresses
 415     // to the page size, so now we just check that the address is
 416     // within the page.  This makes the thread argument unnecessary,
 417     // but we retain the NULL check to preserve existing behavior.
 418     if (thread == NULL) return false;
 419     address page = (address) _mem_serialize_page;
 420     return addr >= page && addr < (page + os::vm_page_size());
 421   }
 422 
 423   static void block_on_serialize_page_trap();
 424 
 425   // threads
 426 
 427   enum ThreadType {
 428     vm_thread,
 429     cgc_thread,        // Concurrent GC thread
 430     pgc_thread,        // Parallel GC thread
 431     java_thread,
 432     compiler_thread,
 433     watcher_thread,
 434     os_thread
 435   };
 436 
 437   static bool create_thread(Thread* thread,
 438                             ThreadType thr_type,
 439                             size_t stack_size = 0);
 440   static bool create_main_thread(JavaThread* thread);
 441   static bool create_attached_thread(JavaThread* thread);
 442   static void pd_start_thread(Thread* thread);
 443   static void start_thread(Thread* thread);
 444 
 445   static void initialize_thread(Thread* thr);
 446   static void free_thread(OSThread* osthread);
 447 
 448   // thread id on Linux/64bit is 64bit, on Windows and Solaris, it's 32bit
 449   static intx current_thread_id();
 450   static int current_process_id();
 451   static int sleep(Thread* thread, jlong ms, bool interruptable);
 452   // Short standalone OS sleep suitable for slow path spin loop.
 453   // Ignores Thread.interrupt() (so keep it short).
 454   // ms = 0, will sleep for the least amount of time allowed by the OS.
 455   static void naked_short_sleep(jlong ms);
 456   static void infinite_sleep(); // never returns, use with CAUTION
 457   static void naked_yield () ;
 458   static OSReturn set_priority(Thread* thread, ThreadPriority priority);
 459   static OSReturn get_priority(const Thread* const thread, ThreadPriority& priority);
 460 
 461   static void interrupt(Thread* thread);
 462   static bool is_interrupted(Thread* thread, bool clear_interrupted);
 463 
 464   static int pd_self_suspend_thread(Thread* thread);
 465 
 466   static ExtendedPC fetch_frame_from_context(void* ucVoid, intptr_t** sp, intptr_t** fp);
 467   static frame      fetch_frame_from_context(void* ucVoid);
 468 
 469   static ExtendedPC get_thread_pc(Thread *thread);
 470   static void breakpoint();
 471 
 472   static address current_stack_pointer();
 473   static address current_stack_base();
 474   static size_t current_stack_size();
 475 
 476   static void verify_stack_alignment() PRODUCT_RETURN;
 477 
 478   static int message_box(const char* title, const char* message);
 479   static char* do_you_want_to_debug(const char* message);
 480 
 481   // run cmd in a separate process and return its exit code; or -1 on failures
 482   static int fork_and_exec(char *cmd);
 483 
 484   // os::exit() is merged with vm_exit()
 485   // static void exit(int num);
 486 
 487   // Terminate the VM, but don't exit the process
 488   static void shutdown();
 489 
 490   // Terminate with an error.  Default is to generate a core file on platforms
 491   // that support such things.  This calls shutdown() and then aborts.
 492   static void abort(bool dump_core = true);
 493 
 494   // Die immediately, no exit hook, no abort hook, no cleanup.
 495   static void die();
 496 
 497   // File i/o operations
 498   static const int default_file_open_flags();
 499   static int open(const char *path, int oflag, int mode);
 500   static FILE* open(int fd, const char* mode);
 501   static int close(int fd);
 502   static jlong lseek(int fd, jlong offset, int whence);
 503   static char* native_path(char *path);
 504   static int ftruncate(int fd, jlong length);
 505   static int fsync(int fd);
 506   static int available(int fd, jlong *bytes);
 507 
 508   //File i/o operations
 509 
 510   static size_t read(int fd, void *buf, unsigned int nBytes);
 511   static size_t restartable_read(int fd, void *buf, unsigned int nBytes);
 512   static size_t write(int fd, const void *buf, unsigned int nBytes);
 513 
 514   // Reading directories.
 515   static DIR*           opendir(const char* dirname);
 516   static int            readdir_buf_size(const char *path);
 517   static struct dirent* readdir(DIR* dirp, dirent* dbuf);
 518   static int            closedir(DIR* dirp);
 519 
 520   // Dynamic library extension
 521   static const char*    dll_file_extension();
 522 
 523   static const char*    get_temp_directory();
 524   static const char*    get_current_directory(char *buf, size_t buflen);
 525 
 526   // Builds a platform-specific full library path given a ld path and lib name
 527   // Returns true if buffer contains full path to existing file, false otherwise
 528   static bool           dll_build_name(char* buffer, size_t size,
 529                                        const char* pathname, const char* fname);
 530 
 531   // Symbol lookup, find nearest function name; basically it implements
 532   // dladdr() for all platforms. Name of the nearest function is copied
 533   // to buf. Distance from its base address is optionally returned as offset.
 534   // If function name is not found, buf[0] is set to '\0' and offset is
 535   // set to -1 (if offset is non-NULL).
 536   static bool dll_address_to_function_name(address addr, char* buf,
 537                                            int buflen, int* offset);
 538 
 539   // Locate DLL/DSO. On success, full path of the library is copied to
 540   // buf, and offset is optionally set to be the distance between addr
 541   // and the library's base address. On failure, buf[0] is set to '\0'
 542   // and offset is set to -1 (if offset is non-NULL).
 543   static bool dll_address_to_library_name(address addr, char* buf,
 544                                           int buflen, int* offset);
 545 
 546   // Find out whether the pc is in the static code for jvm.dll/libjvm.so.
 547   static bool address_is_in_vm(address addr);
 548 
 549   // Loads .dll/.so and
 550   // in case of error it checks if .dll/.so was built for the
 551   // same architecture as HotSpot is running on
 552   static void* dll_load(const char *name, char *ebuf, int ebuflen);
 553 
 554   // lookup symbol in a shared library
 555   static void* dll_lookup(void* handle, const char* name);
 556 
 557   // Unload library
 558   static void  dll_unload(void *lib);
 559 
 560   // Callback for loaded module information
 561   // Input parameters:
 562   //    char*     module_file_name,
 563   //    address   module_base_addr,
 564   //    address   module_top_addr,
 565   //    void*     param
 566   typedef int (*LoadedModulesCallbackFunc)(const char *, address, address, void *);
 567 
 568   static int get_loaded_modules_info(LoadedModulesCallbackFunc callback, void *param);
 569 
 570   // Return the handle of this process
 571   static void* get_default_process_handle();
 572 
 573   // Check for static linked agent library
 574   static bool find_builtin_agent(AgentLibrary *agent_lib, const char *syms[],
 575                                  size_t syms_len);
 576 
 577   // Find agent entry point
 578   static void *find_agent_function(AgentLibrary *agent_lib, bool check_lib,
 579                                    const char *syms[], size_t syms_len);
 580 
 581   // Print out system information; they are called by fatal error handler.
 582   // Output format may be different on different platforms.
 583   static void print_os_info(outputStream* st);
 584   static void print_os_info_brief(outputStream* st);
 585   static void print_cpu_info(outputStream* st);
 586   static void pd_print_cpu_info(outputStream* st);
 587   static void print_memory_info(outputStream* st);
 588   static void print_dll_info(outputStream* st);
 589   static void print_environment_variables(outputStream* st, const char** env_list, char* buffer, int len);
 590   static void print_context(outputStream* st, void* context);
 591   static void print_register_info(outputStream* st, void* context);
 592   static void print_siginfo(outputStream* st, void* siginfo);
 593   static void print_signal_handlers(outputStream* st, char* buf, size_t buflen);
 594   static void print_date_and_time(outputStream* st);
 595 
 596   static void print_location(outputStream* st, intptr_t x, bool verbose = false);
 597   static size_t lasterror(char *buf, size_t len);
 598   static int get_last_error();
 599 
 600   // Determines whether the calling process is being debugged by a user-mode debugger.
 601   static bool is_debugger_attached();
 602 
 603   // wait for a key press if PauseAtExit is set
 604   static void wait_for_keypress_at_exit(void);
 605 
 606   // The following two functions are used by fatal error handler to trace
 607   // native (C) frames. They are not part of frame.hpp/frame.cpp because
 608   // frame.hpp/cpp assume thread is JavaThread, and also because different
 609   // OS/compiler may have different convention or provide different API to
 610   // walk C frames.
 611   //
 612   // We don't attempt to become a debugger, so we only follow frames if that
 613   // does not require a lookup in the unwind table, which is part of the binary
 614   // file but may be unsafe to read after a fatal error. So on x86, we can
 615   // only walk stack if %ebp is used as frame pointer; on ia64, it's not
 616   // possible to walk C stack without having the unwind table.
 617   static bool is_first_C_frame(frame *fr);
 618   static frame get_sender_for_C_frame(frame *fr);
 619 
 620   // return current frame. pc() and sp() are set to NULL on failure.
 621   static frame      current_frame();
 622 
 623   static void print_hex_dump(outputStream* st, address start, address end, int unitsize);
 624 
 625   // returns a string to describe the exception/signal;
 626   // returns NULL if exception_code is not an OS exception/signal.
 627   static const char* exception_name(int exception_code, char* buf, size_t buflen);
 628 
 629   // Returns native Java library, loads if necessary
 630   static void*    native_java_library();
 631 
 632   // Fills in path to jvm.dll/libjvm.so (used by the Disassembler)
 633   static void     jvm_path(char *buf, jint buflen);
 634 
 635   // Returns true if we are running in a headless jre.
 636   static bool     is_headless_jre();
 637 
 638   // JNI names
 639   static void     print_jni_name_prefix_on(outputStream* st, int args_size);
 640   static void     print_jni_name_suffix_on(outputStream* st, int args_size);
 641 
 642   // Init os specific system properties values
 643   static void init_system_properties_values();
 644 
 645   // IO operations, non-JVM_ version.
 646   static int stat(const char* path, struct stat* sbuf);
 647   static bool dir_is_empty(const char* path);
 648 
 649   // IO operations on binary files
 650   static int create_binary_file(const char* path, bool rewrite_existing);
 651   static jlong current_file_offset(int fd);
 652   static jlong seek_to_file_offset(int fd, jlong offset);
 653 
 654   // Thread Local Storage
 655   static int   allocate_thread_local_storage();
 656   static void  thread_local_storage_at_put(int index, void* value);
 657   static void* thread_local_storage_at(int index);
 658   static void  free_thread_local_storage(int index);
 659 
 660   // Retrieve native stack frames.
 661   // Parameter:
 662   //   stack:  an array to storage stack pointers.
 663   //   frames: size of above array.
 664   //   toSkip: number of stack frames to skip at the beginning.
 665   // Return: number of stack frames captured.
 666   static int get_native_stack(address* stack, int size, int toSkip = 0);
 667 
 668   // General allocation (must be MT-safe)
 669   static void* malloc  (size_t size, MEMFLAGS flags, const NativeCallStack& stack);
 670   static void* malloc  (size_t size, MEMFLAGS flags);
 671   static void* realloc (void *memblock, size_t size, MEMFLAGS flag, const NativeCallStack& stack);
 672   static void* realloc (void *memblock, size_t size, MEMFLAGS flag);
 673 
 674   static void  free    (void *memblock, MEMFLAGS flags = mtNone);
 675   static bool  check_heap(bool force = false);      // verify C heap integrity
 676   static char* strdup(const char *, MEMFLAGS flags = mtInternal);  // Like strdup
 677   // Like strdup, but exit VM when strdup() returns NULL
 678   static char* strdup_check_oom(const char*, MEMFLAGS flags = mtInternal);
 679 
 680 #ifndef PRODUCT
 681   static julong num_mallocs;         // # of calls to malloc/realloc
 682   static julong alloc_bytes;         // # of bytes allocated
 683   static julong num_frees;           // # of calls to free
 684   static julong free_bytes;          // # of bytes freed
 685 #endif
 686 
 687   // SocketInterface (ex HPI SocketInterface )
 688   static int socket(int domain, int type, int protocol);
 689   static int socket_close(int fd);
 690   static int socket_shutdown(int fd, int howto);
 691   static int recv(int fd, char* buf, size_t nBytes, uint flags);
 692   static int send(int fd, char* buf, size_t nBytes, uint flags);
 693   static int raw_send(int fd, char* buf, size_t nBytes, uint flags);
 694   static int timeout(int fd, long timeout);
 695   static int listen(int fd, int count);
 696   static int connect(int fd, struct sockaddr* him, socklen_t len);
 697   static int bind(int fd, struct sockaddr* him, socklen_t len);
 698   static int accept(int fd, struct sockaddr* him, socklen_t* len);
 699   static int recvfrom(int fd, char* buf, size_t nbytes, uint flags,
 700                       struct sockaddr* from, socklen_t* fromlen);
 701   static int get_sock_name(int fd, struct sockaddr* him, socklen_t* len);
 702   static int sendto(int fd, char* buf, size_t len, uint flags,
 703                     struct sockaddr* to, socklen_t tolen);
 704   static int socket_available(int fd, jint* pbytes);
 705 
 706   static int get_sock_opt(int fd, int level, int optname,
 707                           char* optval, socklen_t* optlen);
 708   static int set_sock_opt(int fd, int level, int optname,
 709                           const char* optval, socklen_t optlen);
 710   static int get_host_name(char* name, int namelen);
 711 
 712   static struct hostent* get_host_by_name(char* name);
 713 
 714   // Support for signals (see JVM_RaiseSignal, JVM_RegisterSignal)
 715   static void  signal_init();
 716   static void  signal_init_pd();
 717   static void  signal_notify(int signal_number);
 718   static void* signal(int signal_number, void* handler);
 719   static void  signal_raise(int signal_number);
 720   static int   signal_wait();
 721   static int   signal_lookup();
 722   static void* user_handler();
 723   static void  terminate_signal_thread();
 724   static int   sigexitnum_pd();
 725 
 726   // random number generation
 727   static long random();                    // return 32bit pseudorandom number
 728   static void init_random(long initval);   // initialize random sequence
 729 
 730   // Structured OS Exception support
 731   static void os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, JavaCallArguments* args, Thread* thread);
 732 
 733   // On Windows this will create an actual minidump, on Linux/Solaris it will simply check core dump limits
 734   static void check_or_create_dump(void* exceptionRecord, void* contextRecord, char* buffer, size_t bufferSize);
 735 
 736   // Get the default path to the core file
 737   // Returns the length of the string
 738   static int get_core_path(char* buffer, size_t bufferSize);
 739 
 740   // JVMTI & JVM monitoring and management support
 741   // The thread_cpu_time() and current_thread_cpu_time() are only
 742   // supported if is_thread_cpu_time_supported() returns true.
 743   // They are not supported on Solaris T1.
 744 
 745   // Thread CPU Time - return the fast estimate on a platform
 746   // On Solaris - call gethrvtime (fast) - user time only
 747   // On Linux   - fast clock_gettime where available - user+sys
 748   //            - otherwise: very slow /proc fs - user+sys
 749   // On Windows - GetThreadTimes - user+sys
 750   static jlong current_thread_cpu_time();
 751   static jlong thread_cpu_time(Thread* t);
 752 
 753   // Thread CPU Time with user_sys_cpu_time parameter.
 754   //
 755   // If user_sys_cpu_time is true, user+sys time is returned.
 756   // Otherwise, only user time is returned
 757   static jlong current_thread_cpu_time(bool user_sys_cpu_time);
 758   static jlong thread_cpu_time(Thread* t, bool user_sys_cpu_time);
 759 
 760   // Return a bunch of info about the timers.
 761   // Note that the returned info for these two functions may be different
 762   // on some platforms
 763   static void current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr);
 764   static void thread_cpu_time_info(jvmtiTimerInfo *info_ptr);
 765 
 766   static bool is_thread_cpu_time_supported();
 767 
 768   // System loadavg support.  Returns -1 if load average cannot be obtained.
 769   static int loadavg(double loadavg[], int nelem);
 770 
 771   // Hook for os specific jvm options that we don't want to abort on seeing
 772   static bool obsolete_option(const JavaVMOption *option);
 773 
 774   // Extensions
 775 #include "runtime/os_ext.hpp"
 776 
 777  public:
 778   class CrashProtectionCallback : public StackObj {
 779   public:
 780     virtual void call() = 0;
 781   };
 782 
 783   // Platform dependent stuff
 784 #ifdef TARGET_OS_FAMILY_linux
 785 # include "os_linux.hpp"
 786 # include "os_posix.hpp"
 787 #endif
 788 #ifdef TARGET_OS_FAMILY_solaris
 789 # include "os_solaris.hpp"
 790 # include "os_posix.hpp"
 791 #endif
 792 #ifdef TARGET_OS_FAMILY_windows
 793 # include "os_windows.hpp"
 794 #endif
 795 #ifdef TARGET_OS_FAMILY_aix
 796 # include "os_aix.hpp"
 797 # include "os_posix.hpp"
 798 #endif
 799 #ifdef TARGET_OS_FAMILY_bsd
 800 # include "os_posix.hpp"
 801 # include "os_bsd.hpp"
 802 #endif
 803 #ifdef TARGET_OS_ARCH_linux_x86
 804 # include "os_linux_x86.hpp"
 805 #endif
 806 #ifdef TARGET_OS_ARCH_linux_sparc
 807 # include "os_linux_sparc.hpp"
 808 #endif
 809 #ifdef TARGET_OS_ARCH_linux_zero
 810 # include "os_linux_zero.hpp"
 811 #endif
 812 #ifdef TARGET_OS_ARCH_solaris_x86
 813 # include "os_solaris_x86.hpp"
 814 #endif
 815 #ifdef TARGET_OS_ARCH_solaris_sparc
 816 # include "os_solaris_sparc.hpp"
 817 #endif
 818 #ifdef TARGET_OS_ARCH_windows_x86
 819 # include "os_windows_x86.hpp"
 820 #endif
 821 #ifdef TARGET_OS_ARCH_linux_arm
 822 # include "os_linux_arm.hpp"
 823 #endif
 824 #ifdef TARGET_OS_ARCH_linux_ppc
 825 # include "os_linux_ppc.hpp"
 826 #endif
 827 #ifdef TARGET_OS_ARCH_aix_ppc
 828 # include "os_aix_ppc.hpp"
 829 #endif
 830 #ifdef TARGET_OS_ARCH_bsd_x86
 831 # include "os_bsd_x86.hpp"
 832 #endif
 833 #ifdef TARGET_OS_ARCH_bsd_zero
 834 # include "os_bsd_zero.hpp"
 835 #endif
 836 
 837 #ifndef OS_NATIVE_THREAD_CREATION_FAILED_MSG
 838 #define OS_NATIVE_THREAD_CREATION_FAILED_MSG "unable to create native thread: possibly out of memory or process/resource limits reached"
 839 #endif
 840 
 841  public:
 842 #ifndef PLATFORM_PRINT_NATIVE_STACK
 843   // No platform-specific code for printing the native stack.
 844   static bool platform_print_native_stack(outputStream* st, void* context,
 845                                           char *buf, int buf_size) {
 846     return false;
 847   }
 848 #endif
 849 
 850   // debugging support (mostly used by debug.cpp but also fatal error handler)
 851   static bool find(address pc, outputStream* st = tty); // OS specific function to make sense out of an address
 852 
 853   static bool dont_yield();                     // when true, JVM_Yield() is nop
 854   static void print_statistics();
 855 
 856   // Thread priority helpers (implemented in OS-specific part)
 857   static OSReturn set_native_priority(Thread* thread, int native_prio);
 858   static OSReturn get_native_priority(const Thread* const thread, int* priority_ptr);
 859   static int java_to_os_priority[CriticalPriority + 1];
 860   // Hint to the underlying OS that a task switch would not be good.
 861   // Void return because it's a hint and can fail.
 862   static void hint_no_preempt();
 863   static const char* native_thread_creation_failed_msg() {
 864     return OS_NATIVE_THREAD_CREATION_FAILED_MSG;
 865   }
 866 
 867   // Used at creation if requested by the diagnostic flag PauseAtStartup.
 868   // Causes the VM to wait until an external stimulus has been applied
 869   // (for Unix, that stimulus is a signal, for Windows, an external
 870   // ResumeThread call)
 871   static void pause();
 872 
 873   // Builds a platform dependent Agent_OnLoad_<libname> function name
 874   // which is used to find statically linked in agents.
 875   static char*  build_agent_function_name(const char *sym, const char *cname,
 876                                           bool is_absolute_path);
 877 
 878   class SuspendedThreadTaskContext {
 879   public:
 880     SuspendedThreadTaskContext(Thread* thread, void *ucontext) : _thread(thread), _ucontext(ucontext) {}
 881     Thread* thread() const { return _thread; }
 882     void* ucontext() const { return _ucontext; }
 883   private:
 884     Thread* _thread;
 885     void* _ucontext;
 886   };
 887 
 888   class SuspendedThreadTask {
 889   public:
 890     SuspendedThreadTask(Thread* thread) : _thread(thread), _done(false) {}
 891     virtual ~SuspendedThreadTask() {}
 892     void run();
 893     bool is_done() { return _done; }
 894     virtual void do_task(const SuspendedThreadTaskContext& context) = 0;
 895   protected:
 896   private:
 897     void internal_do_task();
 898     Thread* _thread;
 899     bool _done;
 900   };
 901 
 902 #ifndef TARGET_OS_FAMILY_windows
 903   // Suspend/resume support
 904   // Protocol:
 905   //
 906   // a thread starts in SR_RUNNING
 907   //
 908   // SR_RUNNING can go to
 909   //   * SR_SUSPEND_REQUEST when the WatcherThread wants to suspend it
 910   // SR_SUSPEND_REQUEST can go to
 911   //   * SR_RUNNING if WatcherThread decides it waited for SR_SUSPENDED too long (timeout)
 912   //   * SR_SUSPENDED if the stopped thread receives the signal and switches state
 913   // SR_SUSPENDED can go to
 914   //   * SR_WAKEUP_REQUEST when the WatcherThread has done the work and wants to resume
 915   // SR_WAKEUP_REQUEST can go to
 916   //   * SR_RUNNING when the stopped thread receives the signal
 917   //   * SR_WAKEUP_REQUEST on timeout (resend the signal and try again)
 918   class SuspendResume {
 919    public:
 920     enum State {
 921       SR_RUNNING,
 922       SR_SUSPEND_REQUEST,
 923       SR_SUSPENDED,
 924       SR_WAKEUP_REQUEST
 925     };
 926 
 927   private:
 928     volatile State _state;
 929 
 930   private:
 931     /* try to switch state from state "from" to state "to"
 932      * returns the state set after the method is complete
 933      */
 934     State switch_state(State from, State to);
 935 
 936   public:
 937     SuspendResume() : _state(SR_RUNNING) { }
 938 
 939     State state() const { return _state; }
 940 
 941     State request_suspend() {
 942       return switch_state(SR_RUNNING, SR_SUSPEND_REQUEST);
 943     }
 944 
 945     State cancel_suspend() {
 946       return switch_state(SR_SUSPEND_REQUEST, SR_RUNNING);
 947     }
 948 
 949     State suspended() {
 950       return switch_state(SR_SUSPEND_REQUEST, SR_SUSPENDED);
 951     }
 952 
 953     State request_wakeup() {
 954       return switch_state(SR_SUSPENDED, SR_WAKEUP_REQUEST);
 955     }
 956 
 957     State running() {
 958       return switch_state(SR_WAKEUP_REQUEST, SR_RUNNING);
 959     }
 960 
 961     bool is_running() const {
 962       return _state == SR_RUNNING;
 963     }
 964 
 965     bool is_suspend_request() const {
 966       return _state == SR_SUSPEND_REQUEST;
 967     }
 968 
 969     bool is_suspended() const {
 970       return _state == SR_SUSPENDED;
 971     }
 972   };
 973 #endif
 974 
 975 
 976  protected:
 977   static long _rand_seed;                   // seed for random number generator
 978   static int _processor_count;              // number of processors
 979 
 980   static char* format_boot_path(const char* format_string,
 981                                 const char* home,
 982                                 int home_len,
 983                                 char fileSep,
 984                                 char pathSep);
 985   static bool set_boot_path(char fileSep, char pathSep);
 986   static char** split_path(const char* path, int* n);
 987 
 988 };
 989 
 990 // Note that "PAUSE" is almost always used with synchronization
 991 // so arguably we should provide Atomic::SpinPause() instead
 992 // of the global SpinPause() with C linkage.
 993 // It'd also be eligible for inlining on many platforms.
 994 
 995 extern "C" int SpinPause();
 996 
 997 #endif // SHARE_VM_RUNTIME_OS_HPP