1 /*
   2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #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_bsd
  45 # include "jvm_bsd.h"
  46 # include <setjmp.h>
  47 #endif
  48 
  49 // os defines the interface to operating system; this includes traditional
  50 // OS services (time, I/O) as well as other functionality with system-
  51 // dependent code.
  52 
  53 typedef void (*dll_func)(...);
  54 
  55 class Thread;
  56 class JavaThread;
  57 class Event;
  58 class DLL;
  59 class FileHandle;
  60 template<class E> class GrowableArray;
  61 
  62 // %%%%% Moved ThreadState, START_FN, OSThread to new osThread.hpp. -- Rose
  63 
  64 // Platform-independent error return values from OS functions
  65 enum OSReturn {
  66   OS_OK         =  0,        // Operation was successful
  67   OS_ERR        = -1,        // Operation failed
  68   OS_INTRPT     = -2,        // Operation was interrupted
  69   OS_TIMEOUT    = -3,        // Operation timed out
  70   OS_NOMEM      = -5,        // Operation failed for lack of memory
  71   OS_NORESOURCE = -6         // Operation failed for lack of nonmemory resource
  72 };
  73 
  74 enum ThreadPriority {        // JLS 20.20.1-3
  75   NoPriority       = -1,     // Initial non-priority value
  76   MinPriority      =  1,     // Minimum priority
  77   NormPriority     =  5,     // Normal (non-daemon) priority
  78   NearMaxPriority  =  9,     // High priority, used for VMThread
  79   MaxPriority      = 10,     // Highest priority, used for WatcherThread
  80                              // ensures that VMThread doesn't starve profiler
  81   CriticalPriority = 11      // Critical thread priority
  82 };
  83 
  84 // Executable parameter flag for os::commit_memory() and
  85 // os::commit_memory_or_exit().
  86 const bool ExecMem = true;
  87 
  88 // Typedef for structured exception handling support
  89 typedef void (*java_call_t)(JavaValue* value, methodHandle* method, JavaCallArguments* args, Thread* thread);
  90 
  91 class os: AllStatic {
  92  public:
  93   enum { page_sizes_max = 9 }; // Size of _page_sizes array (8 plus a sentinel)
  94 
  95  private:
  96   static OSThread*          _starting_thread;
  97   static address            _polling_page;
  98   static volatile int32_t * _mem_serialize_page;
  99   static uintptr_t          _serialize_page_mask;
 100  public:
 101   static size_t             _page_sizes[page_sizes_max];
 102 
 103  private:
 104   static void init_page_sizes(size_t default_page_size) {
 105     _page_sizes[0] = default_page_size;
 106     _page_sizes[1] = 0; // sentinel
 107   }
 108 
 109   static char*  pd_reserve_memory(size_t bytes, char* addr = 0,
 110                                size_t alignment_hint = 0);
 111   static char*  pd_attempt_reserve_memory_at(size_t bytes, char* addr);
 112   static void   pd_split_reserved_memory(char *base, size_t size,
 113                                       size_t split, bool realloc);
 114   static bool   pd_commit_memory(char* addr, size_t bytes, bool executable);
 115   static bool   pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
 116                                  bool executable);
 117   // Same as pd_commit_memory() that either succeeds or calls
 118   // vm_exit_out_of_memory() with the specified mesg.
 119   static void   pd_commit_memory_or_exit(char* addr, size_t bytes,
 120                                          bool executable, const char* mesg);
 121   static void   pd_commit_memory_or_exit(char* addr, size_t size,
 122                                          size_t alignment_hint,
 123                                          bool executable, const char* mesg);
 124   static bool   pd_uncommit_memory(char* addr, size_t bytes);
 125   static bool   pd_release_memory(char* addr, size_t bytes);
 126 
 127   static char*  pd_map_memory(int fd, const char* file_name, size_t file_offset,
 128                            char *addr, size_t bytes, bool read_only = false,
 129                            bool allow_exec = false);
 130   static char*  pd_remap_memory(int fd, const char* file_name, size_t file_offset,
 131                              char *addr, size_t bytes, bool read_only,
 132                              bool allow_exec);
 133   static bool   pd_unmap_memory(char *addr, size_t bytes);
 134   static void   pd_free_memory(char *addr, size_t bytes, size_t alignment_hint);
 135   static void   pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint);
 136 
 137 
 138  public:
 139   static void init(void);                      // Called before command line parsing
 140   static jint init_2(void);                    // Called after command line parsing
 141   static void init_globals(void) {             // Called from init_globals() in init.cpp
 142     init_globals_ext();
 143   }
 144   static void init_3(void);                    // Called at the end of vm init
 145 
 146   // File names are case-insensitive on windows only
 147   // Override me as needed
 148   static int    file_name_strcmp(const char* s1, const char* s2);
 149 
 150   static bool getenv(const char* name, char* buffer, int len);
 151   static bool have_special_privileges();
 152 
 153   static jlong  javaTimeMillis();
 154   static jlong  javaTimeNanos();
 155   static void   javaTimeNanos_info(jvmtiTimerInfo *info_ptr);
 156   static void   run_periodic_checks();
 157 
 158 
 159   // Returns the elapsed time in seconds since the vm started.
 160   static double elapsedTime();
 161 
 162   // Returns real time in seconds since an arbitrary point
 163   // in the past.
 164   static bool getTimesSecs(double* process_real_time,
 165                            double* process_user_time,
 166                            double* process_system_time);
 167 
 168   // Interface to the performance counter
 169   static jlong elapsed_counter();
 170   static jlong elapsed_frequency();
 171 
 172   // The "virtual time" of a thread is the amount of time a thread has
 173   // actually run.  The first function indicates whether the OS supports
 174   // this functionality for the current thread, and if so:
 175   //   * the second enables vtime tracking (if that is required).
 176   //   * the third tells whether vtime is enabled.
 177   //   * the fourth returns the elapsed virtual time for the current
 178   //     thread.
 179   static bool supports_vtime();
 180   static bool enable_vtime();
 181   static bool vtime_enabled();
 182   static double elapsedVTime();
 183 
 184   // Return current local time in a string (YYYY-MM-DD HH:MM:SS).
 185   // It is MT safe, but not async-safe, as reading time zone
 186   // information may require a lock on some platforms.
 187   static char*      local_time_string(char *buf, size_t buflen);
 188   static struct tm* localtime_pd     (const time_t* clock, struct tm*  res);
 189   // Fill in buffer with current local time as an ISO-8601 string.
 190   // E.g., YYYY-MM-DDThh:mm:ss.mmm+zzzz.
 191   // Returns buffer, or NULL if it failed.
 192   static char* iso8601_time(char* buffer, size_t buffer_length);
 193 
 194   // Interface for detecting multiprocessor system
 195   static inline bool is_MP() {
 196     assert(_processor_count > 0, "invalid processor count");
 197     return _processor_count > 1 || AssumeMP;
 198   }
 199   static julong available_memory();
 200   static julong physical_memory();
 201   static bool has_allocatable_memory_limit(julong* limit);
 202   static bool is_server_class_machine();
 203 
 204   // number of CPUs
 205   static int processor_count() {
 206     return _processor_count;
 207   }
 208   static void set_processor_count(int count) { _processor_count = count; }
 209 
 210   // Returns the number of CPUs this process is currently allowed to run on.
 211   // Note that on some OSes this can change dynamically.
 212   static int active_processor_count();
 213 
 214   // Bind processes to processors.
 215   //     This is a two step procedure:
 216   //     first you generate a distribution of processes to processors,
 217   //     then you bind processes according to that distribution.
 218   // Compute a distribution for number of processes to processors.
 219   //    Stores the processor id's into the distribution array argument.
 220   //    Returns true if it worked, false if it didn't.
 221   static bool distribute_processes(uint length, uint* distribution);
 222   // Binds the current process to a processor.
 223   //    Returns true if it worked, false if it didn't.
 224   static bool bind_to_processor(uint processor_id);
 225 
 226   // Give a name to the current thread.
 227   static void set_native_thread_name(const char *name);
 228 
 229   // Interface for stack banging (predetect possible stack overflow for
 230   // exception processing)  There are guard pages, and above that shadow
 231   // pages for stack overflow checking.
 232   static bool uses_stack_guard_pages();
 233   static bool allocate_stack_guard_pages();
 234   static void bang_stack_shadow_pages();
 235   static bool stack_shadow_pages_available(Thread *thread, methodHandle method);
 236 
 237   // OS interface to Virtual Memory
 238 
 239   // Return the default page size.
 240   static int    vm_page_size();
 241 
 242   // Return the page size to use for a region of memory.  The min_pages argument
 243   // is a hint intended to limit fragmentation; it says the returned page size
 244   // should be <= region_max_size / min_pages.  Because min_pages is a hint,
 245   // this routine may return a size larger than region_max_size / min_pages.
 246   //
 247   // The current implementation ignores min_pages if a larger page size is an
 248   // exact multiple of both region_min_size and region_max_size.  This allows
 249   // larger pages to be used when doing so would not cause fragmentation; in
 250   // particular, a single page can be used when region_min_size ==
 251   // region_max_size == a supported page size.
 252   static size_t page_size_for_region(size_t region_min_size,
 253                                      size_t region_max_size,
 254                                      uint min_pages);
 255 
 256   // Methods for tracing page sizes returned by the above method; enabled by
 257   // TracePageSizes.  The region_{min,max}_size parameters should be the values
 258   // passed to page_size_for_region() and page_size should be the result of that
 259   // call.  The (optional) base and size parameters should come from the
 260   // ReservedSpace base() and size() methods.
 261   static void trace_page_sizes(const char* str, const size_t* page_sizes,
 262                                int count) PRODUCT_RETURN;
 263   static void trace_page_sizes(const char* str, const size_t region_min_size,
 264                                const size_t region_max_size,
 265                                const size_t page_size,
 266                                const char* base = NULL,
 267                                const size_t size = 0) PRODUCT_RETURN;
 268 
 269   static int    vm_allocation_granularity();
 270   static char*  reserve_memory(size_t bytes, char* addr = 0,
 271                                size_t alignment_hint = 0);
 272   static char*  reserve_memory(size_t bytes, char* addr,
 273                                size_t alignment_hint, MEMFLAGS flags);
 274   static char*  reserve_memory_aligned(size_t size, size_t alignment);
 275   static char*  attempt_reserve_memory_at(size_t bytes, char* addr);
 276   static void   split_reserved_memory(char *base, size_t size,
 277                                       size_t split, bool realloc);
 278   static bool   commit_memory(char* addr, size_t bytes, bool executable);
 279   static bool   commit_memory(char* addr, size_t size, size_t alignment_hint,
 280                               bool executable);
 281   // Same as commit_memory() that either succeeds or calls
 282   // vm_exit_out_of_memory() with the specified mesg.
 283   static void   commit_memory_or_exit(char* addr, size_t bytes,
 284                                       bool executable, const char* mesg);
 285   static void   commit_memory_or_exit(char* addr, size_t size,
 286                                       size_t alignment_hint,
 287                                       bool executable, const char* mesg);
 288   static bool   uncommit_memory(char* addr, size_t bytes);
 289   static bool   release_memory(char* addr, size_t bytes);
 290 
 291   enum ProtType { MEM_PROT_NONE, MEM_PROT_READ, MEM_PROT_RW, MEM_PROT_RWX };
 292   static bool   protect_memory(char* addr, size_t bytes, ProtType prot,
 293                                bool is_committed = true);
 294 
 295   static bool   guard_memory(char* addr, size_t bytes);
 296   static bool   unguard_memory(char* addr, size_t bytes);
 297   static bool   create_stack_guard_pages(char* addr, size_t bytes);
 298   static bool   pd_create_stack_guard_pages(char* addr, size_t bytes);
 299   static bool   remove_stack_guard_pages(char* addr, size_t bytes);
 300 
 301   static char*  map_memory(int fd, const char* file_name, size_t file_offset,
 302                            char *addr, size_t bytes, bool read_only = false,
 303                            bool allow_exec = false);
 304   static char*  remap_memory(int fd, const char* file_name, size_t file_offset,
 305                              char *addr, size_t bytes, bool read_only,
 306                              bool allow_exec);
 307   static bool   unmap_memory(char *addr, size_t bytes);
 308   static void   free_memory(char *addr, size_t bytes, size_t alignment_hint);
 309   static void   realign_memory(char *addr, size_t bytes, size_t alignment_hint);
 310 
 311   // NUMA-specific interface
 312   static bool   numa_has_static_binding();
 313   static bool   numa_has_group_homing();
 314   static void   numa_make_local(char *addr, size_t bytes, int lgrp_hint);
 315   static void   numa_make_global(char *addr, size_t bytes);
 316   static size_t numa_get_groups_num();
 317   static size_t numa_get_leaf_groups(int *ids, size_t size);
 318   static bool   numa_topology_changed();
 319   static int    numa_get_group_id();
 320 
 321   // Page manipulation
 322   struct page_info {
 323     size_t size;
 324     int lgrp_id;
 325   };
 326   static bool   get_page_info(char *start, page_info* info);
 327   static char*  scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found);
 328 
 329   static char*  non_memory_address_word();
 330   // reserve, commit and pin the entire memory region
 331   static char*  reserve_memory_special(size_t size, size_t alignment, char* addr, bool executable);
 332   static bool   release_memory_special(char* addr, size_t bytes);
 333   static void   large_page_init();
 334   static size_t large_page_size();
 335   static bool   can_commit_large_page_memory();
 336   static bool   can_execute_large_page_memory();
 337 
 338   // OS interface to polling page
 339   static address get_polling_page()             { return _polling_page; }
 340   static void    set_polling_page(address page) { _polling_page = page; }
 341   static bool    is_poll_address(address addr)  { return addr >= _polling_page && addr < (_polling_page + os::vm_page_size()); }
 342   static void    make_polling_page_unreadable();
 343   static void    make_polling_page_readable();
 344 
 345   // Routines used to serialize the thread state without using membars
 346   static void    serialize_thread_states();
 347 
 348   // Since we write to the serialize page from every thread, we
 349   // want stores to be on unique cache lines whenever possible
 350   // in order to minimize CPU cross talk.  We pre-compute the
 351   // amount to shift the thread* to make this offset unique to
 352   // each thread.
 353   static int     get_serialize_page_shift_count() {
 354     return SerializePageShiftCount;
 355   }
 356 
 357   static void     set_serialize_page_mask(uintptr_t mask) {
 358     _serialize_page_mask = mask;
 359   }
 360 
 361   static unsigned int  get_serialize_page_mask() {
 362     return _serialize_page_mask;
 363   }
 364 
 365   static void    set_memory_serialize_page(address page);
 366 
 367   static address get_memory_serialize_page() {
 368     return (address)_mem_serialize_page;
 369   }
 370 
 371   static inline void write_memory_serialize_page(JavaThread *thread) {
 372     uintptr_t page_offset = ((uintptr_t)thread >>
 373                             get_serialize_page_shift_count()) &
 374                             get_serialize_page_mask();
 375     *(volatile int32_t *)((uintptr_t)_mem_serialize_page+page_offset) = 1;
 376   }
 377 
 378   static bool    is_memory_serialize_page(JavaThread *thread, address addr) {
 379     if (UseMembar) return false;
 380     // Previously this function calculated the exact address of this
 381     // thread's serialize page, and checked if the faulting address
 382     // was equal.  However, some platforms mask off faulting addresses
 383     // to the page size, so now we just check that the address is
 384     // within the page.  This makes the thread argument unnecessary,
 385     // but we retain the NULL check to preserve existing behaviour.
 386     if (thread == NULL) return false;
 387     address page = (address) _mem_serialize_page;
 388     return addr >= page && addr < (page + os::vm_page_size());
 389   }
 390 
 391   static void block_on_serialize_page_trap();
 392 
 393   // threads
 394 
 395   enum ThreadType {
 396     vm_thread,
 397     cgc_thread,        // Concurrent GC thread
 398     pgc_thread,        // Parallel GC thread
 399     java_thread,
 400     compiler_thread,
 401     watcher_thread,
 402     os_thread
 403   };
 404 
 405   static bool create_thread(Thread* thread,
 406                             ThreadType thr_type,
 407                             size_t stack_size = 0);
 408   static bool create_main_thread(JavaThread* thread);
 409   static bool create_attached_thread(JavaThread* thread);
 410   static void pd_start_thread(Thread* thread);
 411   static void start_thread(Thread* thread);
 412 
 413   static void initialize_thread(Thread* thr);
 414   static void free_thread(OSThread* osthread);
 415 
 416   // thread id on Linux/64bit is 64bit, on Windows and Solaris, it's 32bit
 417   static intx current_thread_id();
 418   static int current_process_id();
 419   static int sleep(Thread* thread, jlong ms, bool interruptable);
 420   static int naked_sleep();
 421   static void infinite_sleep(); // never returns, use with CAUTION
 422   static void yield();        // Yields to all threads with same priority
 423   enum YieldResult {
 424     YIELD_SWITCHED = 1,         // caller descheduled, other ready threads exist & ran
 425     YIELD_NONEREADY = 0,        // No other runnable/ready threads.
 426                                 // platform-specific yield return immediately
 427     YIELD_UNKNOWN = -1          // Unknown: platform doesn't support _SWITCHED or _NONEREADY
 428     // YIELD_SWITCHED and YIELD_NONREADY imply the platform supports a "strong"
 429     // yield that can be used in lieu of blocking.
 430   } ;
 431   static YieldResult NakedYield () ;
 432   static void yield_all(int attempts = 0); // Yields to all other threads including lower priority
 433   static void loop_breaker(int attempts);  // called from within tight loops to possibly influence time-sharing
 434   static OSReturn set_priority(Thread* thread, ThreadPriority priority);
 435   static OSReturn get_priority(const Thread* const thread, ThreadPriority& priority);
 436 
 437   static void interrupt(Thread* thread);
 438   static bool is_interrupted(Thread* thread, bool clear_interrupted);
 439 
 440   static int pd_self_suspend_thread(Thread* thread);
 441 
 442   static ExtendedPC fetch_frame_from_context(void* ucVoid, intptr_t** sp, intptr_t** fp);
 443   static frame      fetch_frame_from_context(void* ucVoid);
 444 
 445   static ExtendedPC get_thread_pc(Thread *thread);
 446   static void breakpoint();
 447 
 448   static address current_stack_pointer();
 449   static address current_stack_base();
 450   static size_t current_stack_size();
 451 
 452   static void verify_stack_alignment() PRODUCT_RETURN;
 453 
 454   static int message_box(const char* title, const char* message);
 455   static char* do_you_want_to_debug(const char* message);
 456 
 457   // run cmd in a separate process and return its exit code; or -1 on failures
 458   static int fork_and_exec(char *cmd);
 459 
 460   // Set file to send error reports.
 461   static void set_error_file(const char *logfile);
 462 
 463   // os::exit() is merged with vm_exit()
 464   // static void exit(int num);
 465 
 466   // Terminate the VM, but don't exit the process
 467   static void shutdown();
 468 
 469   // Terminate with an error.  Default is to generate a core file on platforms
 470   // that support such things.  This calls shutdown() and then aborts.
 471   static void abort(bool dump_core = true);
 472 
 473   // Die immediately, no exit hook, no abort hook, no cleanup.
 474   static void die();
 475 
 476   // File i/o operations
 477   static const int default_file_open_flags();
 478   static int open(const char *path, int oflag, int mode);
 479   static FILE* open(int fd, const char* mode);
 480   static int close(int fd);
 481   static jlong lseek(int fd, jlong offset, int whence);
 482   static char* native_path(char *path);
 483   static int ftruncate(int fd, jlong length);
 484   static int fsync(int fd);
 485   static int available(int fd, jlong *bytes);
 486 
 487   //File i/o operations
 488 
 489   static size_t read(int fd, void *buf, unsigned int nBytes);
 490   static size_t restartable_read(int fd, void *buf, unsigned int nBytes);
 491   static size_t write(int fd, const void *buf, unsigned int nBytes);
 492 
 493   // Reading directories.
 494   static DIR*           opendir(const char* dirname);
 495   static int            readdir_buf_size(const char *path);
 496   static struct dirent* readdir(DIR* dirp, dirent* dbuf);
 497   static int            closedir(DIR* dirp);
 498 
 499   // Dynamic library extension
 500   static const char*    dll_file_extension();
 501 
 502   static const char*    get_temp_directory();
 503   static const char*    get_current_directory(char *buf, size_t buflen);
 504 
 505   // Builds a platform-specific full library path given a ld path and lib name
 506   // Returns true if buffer contains full path to existing file, false otherwise
 507   static bool           dll_build_name(char* buffer, size_t size,
 508                                        const char* pathname, const char* fname);
 509 
 510   // Symbol lookup, find nearest function name; basically it implements
 511   // dladdr() for all platforms. Name of the nearest function is copied
 512   // to buf. Distance from its base address is optionally returned as offset.
 513   // If function name is not found, buf[0] is set to '\0' and offset is
 514   // set to -1 (if offset is non-NULL).
 515   static bool dll_address_to_function_name(address addr, char* buf,
 516                                            int buflen, int* offset);
 517 
 518   // Locate DLL/DSO. On success, full path of the library is copied to
 519   // buf, and offset is optionally set to be the distance between addr
 520   // and the library's base address. On failure, buf[0] is set to '\0'
 521   // and offset is set to -1 (if offset is non-NULL).
 522   static bool dll_address_to_library_name(address addr, char* buf,
 523                                           int buflen, int* offset);
 524 
 525   // Find out whether the pc is in the static code for jvm.dll/libjvm.so.
 526   static bool address_is_in_vm(address addr);
 527 
 528   // Loads .dll/.so and
 529   // in case of error it checks if .dll/.so was built for the
 530   // same architecture as Hotspot is running on
 531   static void* dll_load(const char *name, char *ebuf, int ebuflen);
 532 
 533   // lookup symbol in a shared library
 534   static void* dll_lookup(void* handle, const char* name);
 535 
 536   // Unload library
 537   static void  dll_unload(void *lib);
 538 
 539   // Print out system information; they are called by fatal error handler.
 540   // Output format may be different on different platforms.
 541   static void print_os_info(outputStream* st);
 542   static void print_os_info_brief(outputStream* st);
 543   static void print_cpu_info(outputStream* st);
 544   static void pd_print_cpu_info(outputStream* st);
 545   static void print_memory_info(outputStream* st);
 546   static void print_dll_info(outputStream* st);
 547   static void print_environment_variables(outputStream* st, const char** env_list, char* buffer, int len);
 548   static void print_context(outputStream* st, void* context);
 549   static void print_register_info(outputStream* st, void* context);
 550   static void print_siginfo(outputStream* st, void* siginfo);
 551   static void print_signal_handlers(outputStream* st, char* buf, size_t buflen);
 552   static void print_date_and_time(outputStream* st);
 553 
 554   static void print_location(outputStream* st, intptr_t x, bool verbose = false);
 555   static size_t lasterror(char *buf, size_t len);
 556   static int get_last_error();
 557 
 558   // Determines whether the calling process is being debugged by a user-mode debugger.
 559   static bool is_debugger_attached();
 560 
 561   // wait for a key press if PauseAtExit is set
 562   static void wait_for_keypress_at_exit(void);
 563 
 564   // The following two functions are used by fatal error handler to trace
 565   // native (C) frames. They are not part of frame.hpp/frame.cpp because
 566   // frame.hpp/cpp assume thread is JavaThread, and also because different
 567   // OS/compiler may have different convention or provide different API to
 568   // walk C frames.
 569   //
 570   // We don't attempt to become a debugger, so we only follow frames if that
 571   // does not require a lookup in the unwind table, which is part of the binary
 572   // file but may be unsafe to read after a fatal error. So on x86, we can
 573   // only walk stack if %ebp is used as frame pointer; on ia64, it's not
 574   // possible to walk C stack without having the unwind table.
 575   static bool is_first_C_frame(frame *fr);
 576   static frame get_sender_for_C_frame(frame *fr);
 577 
 578   // return current frame. pc() and sp() are set to NULL on failure.
 579   static frame      current_frame();
 580 
 581   static void print_hex_dump(outputStream* st, address start, address end, int unitsize);
 582 
 583   // returns a string to describe the exception/signal;
 584   // returns NULL if exception_code is not an OS exception/signal.
 585   static const char* exception_name(int exception_code, char* buf, size_t buflen);
 586 
 587   // Returns native Java library, loads if necessary
 588   static void*    native_java_library();
 589 
 590   // Fills in path to jvm.dll/libjvm.so (used by the Disassembler)
 591   static void     jvm_path(char *buf, jint buflen);
 592 
 593   // Returns true if we are running in a headless jre.
 594   static bool     is_headless_jre();
 595 
 596   // JNI names
 597   static void     print_jni_name_prefix_on(outputStream* st, int args_size);
 598   static void     print_jni_name_suffix_on(outputStream* st, int args_size);
 599 
 600   // File conventions
 601   static const char* file_separator();
 602   static const char* line_separator();
 603   static const char* path_separator();
 604 
 605   // Init os specific system properties values
 606   static void init_system_properties_values();
 607 
 608   // IO operations, non-JVM_ version.
 609   static int stat(const char* path, struct stat* sbuf);
 610   static bool dir_is_empty(const char* path);
 611 
 612   // IO operations on binary files
 613   static int create_binary_file(const char* path, bool rewrite_existing);
 614   static jlong current_file_offset(int fd);
 615   static jlong seek_to_file_offset(int fd, jlong offset);
 616 
 617   // Thread Local Storage
 618   static int   allocate_thread_local_storage();
 619   static void  thread_local_storage_at_put(int index, void* value);
 620   static void* thread_local_storage_at(int index);
 621   static void  free_thread_local_storage(int index);
 622 
 623   // Stack walk
 624   static address get_caller_pc(int n = 0);
 625 
 626   // General allocation (must be MT-safe)
 627   static void* malloc  (size_t size, MEMFLAGS flags, address caller_pc = 0);
 628   static void* realloc (void *memblock, size_t size, MEMFLAGS flags, address caller_pc = 0);
 629   static void  free    (void *memblock, MEMFLAGS flags = mtNone);
 630   static bool  check_heap(bool force = false);      // verify C heap integrity
 631   static char* strdup(const char *, MEMFLAGS flags = mtInternal);  // Like strdup
 632 
 633 #ifndef PRODUCT
 634   static julong num_mallocs;         // # of calls to malloc/realloc
 635   static julong alloc_bytes;         // # of bytes allocated
 636   static julong num_frees;           // # of calls to free
 637   static julong free_bytes;          // # of bytes freed
 638 #endif
 639 
 640   // SocketInterface (ex HPI SocketInterface )
 641   static int socket(int domain, int type, int protocol);
 642   static int socket_close(int fd);
 643   static int socket_shutdown(int fd, int howto);
 644   static int recv(int fd, char* buf, size_t nBytes, uint flags);
 645   static int send(int fd, char* buf, size_t nBytes, uint flags);
 646   static int raw_send(int fd, char* buf, size_t nBytes, uint flags);
 647   static int timeout(int fd, long timeout);
 648   static int listen(int fd, int count);
 649   static int connect(int fd, struct sockaddr* him, socklen_t len);
 650   static int bind(int fd, struct sockaddr* him, socklen_t len);
 651   static int accept(int fd, struct sockaddr* him, socklen_t* len);
 652   static int recvfrom(int fd, char* buf, size_t nbytes, uint flags,
 653                       struct sockaddr* from, socklen_t* fromlen);
 654   static int get_sock_name(int fd, struct sockaddr* him, socklen_t* len);
 655   static int sendto(int fd, char* buf, size_t len, uint flags,
 656                     struct sockaddr* to, socklen_t tolen);
 657   static int socket_available(int fd, jint* pbytes);
 658 
 659   static int get_sock_opt(int fd, int level, int optname,
 660                           char* optval, socklen_t* optlen);
 661   static int set_sock_opt(int fd, int level, int optname,
 662                           const char* optval, socklen_t optlen);
 663   static int get_host_name(char* name, int namelen);
 664 
 665   static struct hostent* get_host_by_name(char* name);
 666 
 667   // Support for signals (see JVM_RaiseSignal, JVM_RegisterSignal)
 668   static void  signal_init();
 669   static void  signal_init_pd();
 670   static void  signal_notify(int signal_number);
 671   static void* signal(int signal_number, void* handler);
 672   static void  signal_raise(int signal_number);
 673   static int   signal_wait();
 674   static int   signal_lookup();
 675   static void* user_handler();
 676   static void  terminate_signal_thread();
 677   static int   sigexitnum_pd();
 678 
 679   // random number generation
 680   static long random();                    // return 32bit pseudorandom number
 681   static void init_random(long initval);   // initialize random sequence
 682 
 683   // Structured OS Exception support
 684   static void os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, JavaCallArguments* args, Thread* thread);
 685 
 686   // On Windows this will create an actual minidump, on Linux/Solaris it will simply check core dump limits
 687   static void check_or_create_dump(void* exceptionRecord, void* contextRecord, char* buffer, size_t bufferSize);
 688 
 689   // Get the default path to the core file
 690   // Returns the length of the string
 691   static int get_core_path(char* buffer, size_t bufferSize);
 692 
 693   // JVMTI & JVM monitoring and management support
 694   // The thread_cpu_time() and current_thread_cpu_time() are only
 695   // supported if is_thread_cpu_time_supported() returns true.
 696   // They are not supported on Solaris T1.
 697 
 698   // Thread CPU Time - return the fast estimate on a platform
 699   // On Solaris - call gethrvtime (fast) - user time only
 700   // On Linux   - fast clock_gettime where available - user+sys
 701   //            - otherwise: very slow /proc fs - user+sys
 702   // On Windows - GetThreadTimes - user+sys
 703   static jlong current_thread_cpu_time();
 704   static jlong thread_cpu_time(Thread* t);
 705 
 706   // Thread CPU Time with user_sys_cpu_time parameter.
 707   //
 708   // If user_sys_cpu_time is true, user+sys time is returned.
 709   // Otherwise, only user time is returned
 710   static jlong current_thread_cpu_time(bool user_sys_cpu_time);
 711   static jlong thread_cpu_time(Thread* t, bool user_sys_cpu_time);
 712 
 713   // Return a bunch of info about the timers.
 714   // Note that the returned info for these two functions may be different
 715   // on some platforms
 716   static void current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr);
 717   static void thread_cpu_time_info(jvmtiTimerInfo *info_ptr);
 718 
 719   static bool is_thread_cpu_time_supported();
 720 
 721   // System loadavg support.  Returns -1 if load average cannot be obtained.
 722   static int loadavg(double loadavg[], int nelem);
 723 
 724   // Hook for os specific jvm options that we don't want to abort on seeing
 725   static bool obsolete_option(const JavaVMOption *option);
 726 
 727   // Read file line by line. If line is longer than bsize,
 728   // rest of line is skipped. Returns number of bytes read or -1 on EOF
 729   static int get_line_chars(int fd, char *buf, const size_t bsize);
 730 
 731   // Extensions
 732 #include "runtime/os_ext.hpp"
 733 
 734  public:
 735   class CrashProtectionCallback : public StackObj {
 736   public:
 737     virtual void call() = 0;
 738   };
 739 
 740   // Platform dependent stuff
 741 #ifdef TARGET_OS_FAMILY_linux
 742 # include "os_linux.hpp"
 743 # include "os_posix.hpp"
 744 #endif
 745 #ifdef TARGET_OS_FAMILY_solaris
 746 # include "os_solaris.hpp"
 747 # include "os_posix.hpp"
 748 #endif
 749 #ifdef TARGET_OS_FAMILY_windows
 750 # include "os_windows.hpp"
 751 #endif
 752 #ifdef TARGET_OS_FAMILY_bsd
 753 # include "os_posix.hpp"
 754 # include "os_bsd.hpp"
 755 #endif
 756 #ifdef TARGET_OS_ARCH_linux_x86
 757 # include "os_linux_x86.hpp"
 758 #endif
 759 #ifdef TARGET_OS_ARCH_linux_sparc
 760 # include "os_linux_sparc.hpp"
 761 #endif
 762 #ifdef TARGET_OS_ARCH_linux_zero
 763 # include "os_linux_zero.hpp"
 764 #endif
 765 #ifdef TARGET_OS_ARCH_solaris_x86
 766 # include "os_solaris_x86.hpp"
 767 #endif
 768 #ifdef TARGET_OS_ARCH_solaris_sparc
 769 # include "os_solaris_sparc.hpp"
 770 #endif
 771 #ifdef TARGET_OS_ARCH_windows_x86
 772 # include "os_windows_x86.hpp"
 773 #endif
 774 #ifdef TARGET_OS_ARCH_linux_arm
 775 # include "os_linux_arm.hpp"
 776 #endif
 777 #ifdef TARGET_OS_ARCH_linux_ppc
 778 # include "os_linux_ppc.hpp"
 779 #endif
 780 #ifdef TARGET_OS_ARCH_bsd_x86
 781 # include "os_bsd_x86.hpp"
 782 #endif
 783 #ifdef TARGET_OS_ARCH_bsd_zero
 784 # include "os_bsd_zero.hpp"
 785 #endif
 786 
 787  public:
 788   // debugging support (mostly used by debug.cpp but also fatal error handler)
 789   static bool find(address pc, outputStream* st = tty); // OS specific function to make sense out of an address
 790 
 791   static bool dont_yield();                     // when true, JVM_Yield() is nop
 792   static void print_statistics();
 793 
 794   // Thread priority helpers (implemented in OS-specific part)
 795   static OSReturn set_native_priority(Thread* thread, int native_prio);
 796   static OSReturn get_native_priority(const Thread* const thread, int* priority_ptr);
 797   static int java_to_os_priority[CriticalPriority + 1];
 798   // Hint to the underlying OS that a task switch would not be good.
 799   // Void return because it's a hint and can fail.
 800   static void hint_no_preempt();
 801 
 802   // Used at creation if requested by the diagnostic flag PauseAtStartup.
 803   // Causes the VM to wait until an external stimulus has been applied
 804   // (for Unix, that stimulus is a signal, for Windows, an external
 805   // ResumeThread call)
 806   static void pause();
 807 
 808   class SuspendedThreadTaskContext {
 809   public:
 810     SuspendedThreadTaskContext(Thread* thread, void *ucontext) : _thread(thread), _ucontext(ucontext) {}
 811     Thread* thread() const { return _thread; }
 812     void* ucontext() const { return _ucontext; }
 813   private:
 814     Thread* _thread;
 815     void* _ucontext;
 816   };
 817 
 818   class SuspendedThreadTask {
 819   public:
 820     SuspendedThreadTask(Thread* thread) : _thread(thread), _done(false) {}
 821     virtual ~SuspendedThreadTask() {}
 822     void run();
 823     bool is_done() { return _done; }
 824     virtual void do_task(const SuspendedThreadTaskContext& context) = 0;
 825   protected:
 826   private:
 827     void internal_do_task();
 828     Thread* _thread;
 829     bool _done;
 830   };
 831 
 832 #ifndef TARGET_OS_FAMILY_windows
 833   // Suspend/resume support
 834   // Protocol:
 835   //
 836   // a thread starts in SR_RUNNING
 837   //
 838   // SR_RUNNING can go to
 839   //   * SR_SUSPEND_REQUEST when the WatcherThread wants to suspend it
 840   // SR_SUSPEND_REQUEST can go to
 841   //   * SR_RUNNING if WatcherThread decides it waited for SR_SUSPENDED too long (timeout)
 842   //   * SR_SUSPENDED if the stopped thread receives the signal and switches state
 843   // SR_SUSPENDED can go to
 844   //   * SR_WAKEUP_REQUEST when the WatcherThread has done the work and wants to resume
 845   // SR_WAKEUP_REQUEST can go to
 846   //   * SR_RUNNING when the stopped thread receives the signal
 847   //   * SR_WAKEUP_REQUEST on timeout (resend the signal and try again)
 848   class SuspendResume {
 849    public:
 850     enum State {
 851       SR_RUNNING,
 852       SR_SUSPEND_REQUEST,
 853       SR_SUSPENDED,
 854       SR_WAKEUP_REQUEST
 855     };
 856 
 857   private:
 858     volatile State _state;
 859 
 860   private:
 861     /* try to switch state from state "from" to state "to"
 862      * returns the state set after the method is complete
 863      */
 864     State switch_state(State from, State to);
 865 
 866   public:
 867     SuspendResume() : _state(SR_RUNNING) { }
 868 
 869     State state() const { return _state; }
 870 
 871     State request_suspend() {
 872       return switch_state(SR_RUNNING, SR_SUSPEND_REQUEST);
 873     }
 874 
 875     State cancel_suspend() {
 876       return switch_state(SR_SUSPEND_REQUEST, SR_RUNNING);
 877     }
 878 
 879     State suspended() {
 880       return switch_state(SR_SUSPEND_REQUEST, SR_SUSPENDED);
 881     }
 882 
 883     State request_wakeup() {
 884       return switch_state(SR_SUSPENDED, SR_WAKEUP_REQUEST);
 885     }
 886 
 887     State running() {
 888       return switch_state(SR_WAKEUP_REQUEST, SR_RUNNING);
 889     }
 890 
 891     bool is_running() const {
 892       return _state == SR_RUNNING;
 893     }
 894 
 895     bool is_suspend_request() const {
 896       return _state == SR_SUSPEND_REQUEST;
 897     }
 898 
 899     bool is_suspended() const {
 900       return _state == SR_SUSPENDED;
 901     }
 902   };
 903 #endif
 904 
 905 
 906  protected:
 907   static long _rand_seed;                   // seed for random number generator
 908   static int _processor_count;              // number of processors
 909 
 910   static char* format_boot_path(const char* format_string,
 911                                 const char* home,
 912                                 int home_len,
 913                                 char fileSep,
 914                                 char pathSep);
 915   static bool set_boot_path(char fileSep, char pathSep);
 916   static char** split_path(const char* path, int* n);
 917 
 918 };
 919 
 920 // Note that "PAUSE" is almost always used with synchronization
 921 // so arguably we should provide Atomic::SpinPause() instead
 922 // of the global SpinPause() with C linkage.
 923 // It'd also be eligible for inlining on many platforms.
 924 
 925 extern "C" int SpinPause();
 926 
 927 #endif // SHARE_VM_RUNTIME_OS_HPP