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