os.hpp revision 3644:716e6ef4482a
1/*
2 * Copyright (c) 1997, 2012, 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#endif
36#ifdef TARGET_OS_FAMILY_solaris
37# include "jvm_solaris.h"
38#endif
39#ifdef TARGET_OS_FAMILY_windows
40# include "jvm_windows.h"
41#endif
42#ifdef TARGET_OS_FAMILY_bsd
43# include "jvm_bsd.h"
44#endif
45
46// os defines the interface to operating system; this includes traditional
47// OS services (time, I/O) as well as other functionality with system-
48// dependent code.
49
50typedef void (*dll_func)(...);
51
52class Thread;
53class JavaThread;
54class Event;
55class DLL;
56class FileHandle;
57template<class E> class GrowableArray;
58
59// %%%%% Moved ThreadState, START_FN, OSThread to new osThread.hpp. -- Rose
60
61// Platform-independent error return values from OS functions
62enum OSReturn {
63  OS_OK         =  0,        // Operation was successful
64  OS_ERR        = -1,        // Operation failed
65  OS_INTRPT     = -2,        // Operation was interrupted
66  OS_TIMEOUT    = -3,        // Operation timed out
67  OS_NOMEM      = -5,        // Operation failed for lack of memory
68  OS_NORESOURCE = -6         // Operation failed for lack of nonmemory resource
69};
70
71enum ThreadPriority {        // JLS 20.20.1-3
72  NoPriority       = -1,     // Initial non-priority value
73  MinPriority      =  1,     // Minimum priority
74  NormPriority     =  5,     // Normal (non-daemon) priority
75  NearMaxPriority  =  9,     // High priority, used for VMThread
76  MaxPriority      = 10,     // Highest priority, used for WatcherThread
77                             // ensures that VMThread doesn't starve profiler
78  CriticalPriority = 11      // Critical thread priority
79};
80
81// Typedef for structured exception handling support
82typedef void (*java_call_t)(JavaValue* value, methodHandle* method, JavaCallArguments* args, Thread* thread);
83
84class os: AllStatic {
85 public:
86  enum { page_sizes_max = 9 }; // Size of _page_sizes array (8 plus a sentinel)
87
88 private:
89  static OSThread*          _starting_thread;
90  static address            _polling_page;
91  static volatile int32_t * _mem_serialize_page;
92  static uintptr_t          _serialize_page_mask;
93 public:
94  static size_t             _page_sizes[page_sizes_max];
95
96 private:
97  static void init_page_sizes(size_t default_page_size) {
98    _page_sizes[0] = default_page_size;
99    _page_sizes[1] = 0; // sentinel
100  }
101
102  static char*  pd_reserve_memory(size_t bytes, char* addr = 0,
103                               size_t alignment_hint = 0);
104  static char*  pd_attempt_reserve_memory_at(size_t bytes, char* addr);
105  static void   pd_split_reserved_memory(char *base, size_t size,
106                                      size_t split, bool realloc);
107  static bool   pd_commit_memory(char* addr, size_t bytes, bool executable = false);
108  static bool   pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
109                              bool executable = false);
110  static bool   pd_uncommit_memory(char* addr, size_t bytes);
111  static bool   pd_release_memory(char* addr, size_t bytes);
112
113  static char*  pd_map_memory(int fd, const char* file_name, size_t file_offset,
114                           char *addr, size_t bytes, bool read_only = false,
115                           bool allow_exec = false);
116  static char*  pd_remap_memory(int fd, const char* file_name, size_t file_offset,
117                             char *addr, size_t bytes, bool read_only,
118                             bool allow_exec);
119  static bool   pd_unmap_memory(char *addr, size_t bytes);
120  static void   pd_free_memory(char *addr, size_t bytes, size_t alignment_hint);
121  static void   pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint);
122
123
124 public:
125  static void init(void);                      // Called before command line parsing
126  static jint init_2(void);                    // Called after command line parsing
127  static void init_globals(void) {             // Called from init_globals() in init.cpp
128    init_globals_ext();
129  }
130  static void init_3(void);                    // Called at the end of vm init
131
132  // File names are case-insensitive on windows only
133  // Override me as needed
134  static int    file_name_strcmp(const char* s1, const char* s2);
135
136  static bool getenv(const char* name, char* buffer, int len);
137  static bool have_special_privileges();
138
139  static jlong  javaTimeMillis();
140  static jlong  javaTimeNanos();
141  static void   javaTimeNanos_info(jvmtiTimerInfo *info_ptr);
142  static void   run_periodic_checks();
143
144
145  // Returns the elapsed time in seconds since the vm started.
146  static double elapsedTime();
147
148  // Returns real time in seconds since an arbitrary point
149  // in the past.
150  static bool getTimesSecs(double* process_real_time,
151                           double* process_user_time,
152                           double* process_system_time);
153
154  // Interface to the performance counter
155  static jlong elapsed_counter();
156  static jlong elapsed_frequency();
157
158  // The "virtual time" of a thread is the amount of time a thread has
159  // actually run.  The first function indicates whether the OS supports
160  // this functionality for the current thread, and if so:
161  //   * the second enables vtime tracking (if that is required).
162  //   * the third tells whether vtime is enabled.
163  //   * the fourth returns the elapsed virtual time for the current
164  //     thread.
165  static bool supports_vtime();
166  static bool enable_vtime();
167  static bool vtime_enabled();
168  static double elapsedVTime();
169
170  // Return current local time in a string (YYYY-MM-DD HH:MM:SS).
171  // It is MT safe, but not async-safe, as reading time zone
172  // information may require a lock on some platforms.
173  static char*      local_time_string(char *buf, size_t buflen);
174  static struct tm* localtime_pd     (const time_t* clock, struct tm*  res);
175  // Fill in buffer with current local time as an ISO-8601 string.
176  // E.g., YYYY-MM-DDThh:mm:ss.mmm+zzzz.
177  // Returns buffer, or NULL if it failed.
178  static char* iso8601_time(char* buffer, size_t buffer_length);
179
180  // Interface for detecting multiprocessor system
181  static inline bool is_MP() {
182    assert(_processor_count > 0, "invalid processor count");
183    return _processor_count > 1;
184  }
185  static julong available_memory();
186  static julong physical_memory();
187  static julong allocatable_physical_memory(julong size);
188  static bool is_server_class_machine();
189
190  // number of CPUs
191  static int processor_count() {
192    return _processor_count;
193  }
194  static void set_processor_count(int count) { _processor_count = count; }
195
196  // Returns the number of CPUs this process is currently allowed to run on.
197  // Note that on some OSes this can change dynamically.
198  static int active_processor_count();
199
200  // Bind processes to processors.
201  //     This is a two step procedure:
202  //     first you generate a distribution of processes to processors,
203  //     then you bind processes according to that distribution.
204  // Compute a distribution for number of processes to processors.
205  //    Stores the processor id's into the distribution array argument.
206  //    Returns true if it worked, false if it didn't.
207  static bool distribute_processes(uint length, uint* distribution);
208  // Binds the current process to a processor.
209  //    Returns true if it worked, false if it didn't.
210  static bool bind_to_processor(uint processor_id);
211
212  // Give a name to the current thread.
213  static void set_native_thread_name(const char *name);
214
215  // Interface for stack banging (predetect possible stack overflow for
216  // exception processing)  There are guard pages, and above that shadow
217  // pages for stack overflow checking.
218  static bool uses_stack_guard_pages();
219  static bool allocate_stack_guard_pages();
220  static void bang_stack_shadow_pages();
221  static bool stack_shadow_pages_available(Thread *thread, methodHandle method);
222
223  // OS interface to Virtual Memory
224
225  // Return the default page size.
226  static int    vm_page_size();
227
228  // Return the page size to use for a region of memory.  The min_pages argument
229  // is a hint intended to limit fragmentation; it says the returned page size
230  // should be <= region_max_size / min_pages.  Because min_pages is a hint,
231  // this routine may return a size larger than region_max_size / min_pages.
232  //
233  // The current implementation ignores min_pages if a larger page size is an
234  // exact multiple of both region_min_size and region_max_size.  This allows
235  // larger pages to be used when doing so would not cause fragmentation; in
236  // particular, a single page can be used when region_min_size ==
237  // region_max_size == a supported page size.
238  static size_t page_size_for_region(size_t region_min_size,
239                                     size_t region_max_size,
240                                     uint min_pages);
241
242  // Methods for tracing page sizes returned by the above method; enabled by
243  // TracePageSizes.  The region_{min,max}_size parameters should be the values
244  // passed to page_size_for_region() and page_size should be the result of that
245  // call.  The (optional) base and size parameters should come from the
246  // ReservedSpace base() and size() methods.
247  static void trace_page_sizes(const char* str, const size_t* page_sizes,
248                               int count) PRODUCT_RETURN;
249  static void trace_page_sizes(const char* str, const size_t region_min_size,
250                               const size_t region_max_size,
251                               const size_t page_size,
252                               const char* base = NULL,
253                               const size_t size = 0) PRODUCT_RETURN;
254
255  static int    vm_allocation_granularity();
256  static char*  reserve_memory(size_t bytes, char* addr = 0,
257                               size_t alignment_hint = 0);
258  static char*  attempt_reserve_memory_at(size_t bytes, char* addr);
259  static void   split_reserved_memory(char *base, size_t size,
260                                      size_t split, bool realloc);
261  static bool   commit_memory(char* addr, size_t bytes, bool executable = false);
262  static bool   commit_memory(char* addr, size_t size, size_t alignment_hint,
263                              bool executable = false);
264  static bool   uncommit_memory(char* addr, size_t bytes);
265  static bool   release_memory(char* addr, size_t bytes);
266
267  enum ProtType { MEM_PROT_NONE, MEM_PROT_READ, MEM_PROT_RW, MEM_PROT_RWX };
268  static bool   protect_memory(char* addr, size_t bytes, ProtType prot,
269                               bool is_committed = true);
270
271  static bool   guard_memory(char* addr, size_t bytes);
272  static bool   unguard_memory(char* addr, size_t bytes);
273  static bool   create_stack_guard_pages(char* addr, size_t bytes);
274  static bool   pd_create_stack_guard_pages(char* addr, size_t bytes);
275  static bool   remove_stack_guard_pages(char* addr, size_t bytes);
276
277  static char*  map_memory(int fd, const char* file_name, size_t file_offset,
278                           char *addr, size_t bytes, bool read_only = false,
279                           bool allow_exec = false);
280  static char*  remap_memory(int fd, const char* file_name, size_t file_offset,
281                             char *addr, size_t bytes, bool read_only,
282                             bool allow_exec);
283  static bool   unmap_memory(char *addr, size_t bytes);
284  static void   free_memory(char *addr, size_t bytes, size_t alignment_hint);
285  static void   realign_memory(char *addr, size_t bytes, size_t alignment_hint);
286
287  // NUMA-specific interface
288  static bool   numa_has_static_binding();
289  static bool   numa_has_group_homing();
290  static void   numa_make_local(char *addr, size_t bytes, int lgrp_hint);
291  static void   numa_make_global(char *addr, size_t bytes);
292  static size_t numa_get_groups_num();
293  static size_t numa_get_leaf_groups(int *ids, size_t size);
294  static bool   numa_topology_changed();
295  static int    numa_get_group_id();
296
297  // Page manipulation
298  struct page_info {
299    size_t size;
300    int lgrp_id;
301  };
302  static bool   get_page_info(char *start, page_info* info);
303  static char*  scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found);
304
305  static char*  non_memory_address_word();
306  // reserve, commit and pin the entire memory region
307  static char*  reserve_memory_special(size_t size, char* addr = NULL,
308                bool executable = false);
309  static bool   release_memory_special(char* addr, size_t bytes);
310  static void   large_page_init();
311  static size_t large_page_size();
312  static bool   can_commit_large_page_memory();
313  static bool   can_execute_large_page_memory();
314
315  // OS interface to polling page
316  static address get_polling_page()             { return _polling_page; }
317  static void    set_polling_page(address page) { _polling_page = page; }
318  static bool    is_poll_address(address addr)  { return addr >= _polling_page && addr < (_polling_page + os::vm_page_size()); }
319  static void    make_polling_page_unreadable();
320  static void    make_polling_page_readable();
321
322  // Routines used to serialize the thread state without using membars
323  static void    serialize_thread_states();
324
325  // Since we write to the serialize page from every thread, we
326  // want stores to be on unique cache lines whenever possible
327  // in order to minimize CPU cross talk.  We pre-compute the
328  // amount to shift the thread* to make this offset unique to
329  // each thread.
330  static int     get_serialize_page_shift_count() {
331    return SerializePageShiftCount;
332  }
333
334  static void     set_serialize_page_mask(uintptr_t mask) {
335    _serialize_page_mask = mask;
336  }
337
338  static unsigned int  get_serialize_page_mask() {
339    return _serialize_page_mask;
340  }
341
342  static void    set_memory_serialize_page(address page);
343
344  static address get_memory_serialize_page() {
345    return (address)_mem_serialize_page;
346  }
347
348  static inline void write_memory_serialize_page(JavaThread *thread) {
349    uintptr_t page_offset = ((uintptr_t)thread >>
350                            get_serialize_page_shift_count()) &
351                            get_serialize_page_mask();
352    *(volatile int32_t *)((uintptr_t)_mem_serialize_page+page_offset) = 1;
353  }
354
355  static bool    is_memory_serialize_page(JavaThread *thread, address addr) {
356    if (UseMembar) return false;
357    // Previously this function calculated the exact address of this
358    // thread's serialize page, and checked if the faulting address
359    // was equal.  However, some platforms mask off faulting addresses
360    // to the page size, so now we just check that the address is
361    // within the page.  This makes the thread argument unnecessary,
362    // but we retain the NULL check to preserve existing behaviour.
363    if (thread == NULL) return false;
364    address page = (address) _mem_serialize_page;
365    return addr >= page && addr < (page + os::vm_page_size());
366  }
367
368  static void block_on_serialize_page_trap();
369
370  // threads
371
372  enum ThreadType {
373    vm_thread,
374    cgc_thread,        // Concurrent GC thread
375    pgc_thread,        // Parallel GC thread
376    java_thread,
377    compiler_thread,
378    watcher_thread,
379    os_thread
380  };
381
382  static bool create_thread(Thread* thread,
383                            ThreadType thr_type,
384                            size_t stack_size = 0);
385  static bool create_main_thread(JavaThread* thread);
386  static bool create_attached_thread(JavaThread* thread);
387  static void pd_start_thread(Thread* thread);
388  static void start_thread(Thread* thread);
389
390  static void initialize_thread(Thread* thr);
391  static void free_thread(OSThread* osthread);
392
393  // thread id on Linux/64bit is 64bit, on Windows and Solaris, it's 32bit
394  static intx current_thread_id();
395  static int current_process_id();
396  static int sleep(Thread* thread, jlong ms, bool interruptable);
397  static int naked_sleep();
398  static void infinite_sleep(); // never returns, use with CAUTION
399  static void yield();        // Yields to all threads with same priority
400  enum YieldResult {
401    YIELD_SWITCHED = 1,         // caller descheduled, other ready threads exist & ran
402    YIELD_NONEREADY = 0,        // No other runnable/ready threads.
403                                // platform-specific yield return immediately
404    YIELD_UNKNOWN = -1          // Unknown: platform doesn't support _SWITCHED or _NONEREADY
405    // YIELD_SWITCHED and YIELD_NONREADY imply the platform supports a "strong"
406    // yield that can be used in lieu of blocking.
407  } ;
408  static YieldResult NakedYield () ;
409  static void yield_all(int attempts = 0); // Yields to all other threads including lower priority
410  static void loop_breaker(int attempts);  // called from within tight loops to possibly influence time-sharing
411  static OSReturn set_priority(Thread* thread, ThreadPriority priority);
412  static OSReturn get_priority(const Thread* const thread, ThreadPriority& priority);
413
414  static void interrupt(Thread* thread);
415  static bool is_interrupted(Thread* thread, bool clear_interrupted);
416
417  static int pd_self_suspend_thread(Thread* thread);
418
419  static ExtendedPC fetch_frame_from_context(void* ucVoid, intptr_t** sp, intptr_t** fp);
420  static frame      fetch_frame_from_context(void* ucVoid);
421
422  static ExtendedPC get_thread_pc(Thread *thread);
423  static void breakpoint();
424
425  static address current_stack_pointer();
426  static address current_stack_base();
427  static size_t current_stack_size();
428
429  static void verify_stack_alignment() PRODUCT_RETURN;
430
431  static int message_box(const char* title, const char* message);
432  static char* do_you_want_to_debug(const char* message);
433
434  // run cmd in a separate process and return its exit code; or -1 on failures
435  static int fork_and_exec(char *cmd);
436
437  // Set file to send error reports.
438  static void set_error_file(const char *logfile);
439
440  // os::exit() is merged with vm_exit()
441  // static void exit(int num);
442
443  // Terminate the VM, but don't exit the process
444  static void shutdown();
445
446  // Terminate with an error.  Default is to generate a core file on platforms
447  // that support such things.  This calls shutdown() and then aborts.
448  static void abort(bool dump_core = true);
449
450  // Die immediately, no exit hook, no abort hook, no cleanup.
451  static void die();
452
453  // File i/o operations
454  static const int default_file_open_flags();
455  static int open(const char *path, int oflag, int mode);
456  static int close(int fd);
457  static jlong lseek(int fd, jlong offset, int whence);
458  static char* native_path(char *path);
459  static int ftruncate(int fd, jlong length);
460  static int fsync(int fd);
461  static int available(int fd, jlong *bytes);
462
463  //File i/o operations
464
465  static size_t read(int fd, void *buf, unsigned int nBytes);
466  static size_t restartable_read(int fd, void *buf, unsigned int nBytes);
467  static size_t write(int fd, const void *buf, unsigned int nBytes);
468
469  // Reading directories.
470  static DIR*           opendir(const char* dirname);
471  static int            readdir_buf_size(const char *path);
472  static struct dirent* readdir(DIR* dirp, dirent* dbuf);
473  static int            closedir(DIR* dirp);
474
475  // Dynamic library extension
476  static const char*    dll_file_extension();
477
478  static const char*    get_temp_directory();
479  static const char*    get_current_directory(char *buf, int buflen);
480
481  // Builds a platform-specific full library path given a ld path and lib name
482  static void           dll_build_name(char* buffer, size_t size,
483                                       const char* pathname, const char* fname);
484
485  // Symbol lookup, find nearest function name; basically it implements
486  // dladdr() for all platforms. Name of the nearest function is copied
487  // to buf. Distance from its base address is returned as offset.
488  // If function name is not found, buf[0] is set to '\0' and offset is
489  // set to -1.
490  static bool dll_address_to_function_name(address addr, char* buf,
491                                           int buflen, int* offset);
492
493  // Locate DLL/DSO. On success, full path of the library is copied to
494  // buf, and offset is set to be the distance between addr and the
495  // library's base address. On failure, buf[0] is set to '\0' and
496  // offset is set to -1.
497  static bool dll_address_to_library_name(address addr, char* buf,
498                                          int buflen, int* offset);
499
500  // Find out whether the pc is in the static code for jvm.dll/libjvm.so.
501  static bool address_is_in_vm(address addr);
502
503  // Loads .dll/.so and
504  // in case of error it checks if .dll/.so was built for the
505  // same architecture as Hotspot is running on
506  static void* dll_load(const char *name, char *ebuf, int ebuflen);
507
508  // lookup symbol in a shared library
509  static void* dll_lookup(void* handle, const char* name);
510
511  // Unload library
512  static void  dll_unload(void *lib);
513
514  // Print out system information; they are called by fatal error handler.
515  // Output format may be different on different platforms.
516  static void print_os_info(outputStream* st);
517  static void print_os_info_brief(outputStream* st);
518  static void print_cpu_info(outputStream* st);
519  static void pd_print_cpu_info(outputStream* st);
520  static void print_memory_info(outputStream* st);
521  static void print_dll_info(outputStream* st);
522  static void print_environment_variables(outputStream* st, const char** env_list, char* buffer, int len);
523  static void print_context(outputStream* st, void* context);
524  static void print_register_info(outputStream* st, void* context);
525  static void print_siginfo(outputStream* st, void* siginfo);
526  static void print_signal_handlers(outputStream* st, char* buf, size_t buflen);
527  static void print_date_and_time(outputStream* st);
528
529  static void print_location(outputStream* st, intptr_t x, bool verbose = false);
530  static size_t lasterror(char *buf, size_t len);
531  static int get_last_error();
532
533  // Determines whether the calling process is being debugged by a user-mode debugger.
534  static bool is_debugger_attached();
535
536  // wait for a key press if PauseAtExit is set
537  static void wait_for_keypress_at_exit(void);
538
539  // The following two functions are used by fatal error handler to trace
540  // native (C) frames. They are not part of frame.hpp/frame.cpp because
541  // frame.hpp/cpp assume thread is JavaThread, and also because different
542  // OS/compiler may have different convention or provide different API to
543  // walk C frames.
544  //
545  // We don't attempt to become a debugger, so we only follow frames if that
546  // does not require a lookup in the unwind table, which is part of the binary
547  // file but may be unsafe to read after a fatal error. So on x86, we can
548  // only walk stack if %ebp is used as frame pointer; on ia64, it's not
549  // possible to walk C stack without having the unwind table.
550  static bool is_first_C_frame(frame *fr);
551  static frame get_sender_for_C_frame(frame *fr);
552
553  // return current frame. pc() and sp() are set to NULL on failure.
554  static frame      current_frame();
555
556  static void print_hex_dump(outputStream* st, address start, address end, int unitsize);
557
558  // returns a string to describe the exception/signal;
559  // returns NULL if exception_code is not an OS exception/signal.
560  static const char* exception_name(int exception_code, char* buf, size_t buflen);
561
562  // Returns native Java library, loads if necessary
563  static void*    native_java_library();
564
565  // Fills in path to jvm.dll/libjvm.so (used by the Disassembler)
566  static void     jvm_path(char *buf, jint buflen);
567
568  // Returns true if we are running in a headless jre.
569  static bool     is_headless_jre();
570
571  // JNI names
572  static void     print_jni_name_prefix_on(outputStream* st, int args_size);
573  static void     print_jni_name_suffix_on(outputStream* st, int args_size);
574
575  // File conventions
576  static const char* file_separator();
577  static const char* line_separator();
578  static const char* path_separator();
579
580  // Init os specific system properties values
581  static void init_system_properties_values();
582
583  // IO operations, non-JVM_ version.
584  static int stat(const char* path, struct stat* sbuf);
585  static bool dir_is_empty(const char* path);
586
587  // IO operations on binary files
588  static int create_binary_file(const char* path, bool rewrite_existing);
589  static jlong current_file_offset(int fd);
590  static jlong seek_to_file_offset(int fd, jlong offset);
591
592  // Thread Local Storage
593  static int   allocate_thread_local_storage();
594  static void  thread_local_storage_at_put(int index, void* value);
595  static void* thread_local_storage_at(int index);
596  static void  free_thread_local_storage(int index);
597
598  // Stack walk
599  static address get_caller_pc(int n = 0);
600
601  // General allocation (must be MT-safe)
602  static void* malloc  (size_t size, MEMFLAGS flags, address caller_pc = 0);
603  static void* realloc (void *memblock, size_t size, MEMFLAGS flags, address caller_pc = 0);
604  static void  free    (void *memblock, MEMFLAGS flags = mtNone);
605  static bool  check_heap(bool force = false);      // verify C heap integrity
606  static char* strdup(const char *, MEMFLAGS flags = mtInternal);  // Like strdup
607
608#ifndef PRODUCT
609  static julong num_mallocs;         // # of calls to malloc/realloc
610  static julong alloc_bytes;         // # of bytes allocated
611  static julong num_frees;           // # of calls to free
612  static julong free_bytes;          // # of bytes freed
613#endif
614
615  // SocketInterface (ex HPI SocketInterface )
616  static int socket(int domain, int type, int protocol);
617  static int socket_close(int fd);
618  static int socket_shutdown(int fd, int howto);
619  static int recv(int fd, char* buf, size_t nBytes, uint flags);
620  static int send(int fd, char* buf, size_t nBytes, uint flags);
621  static int raw_send(int fd, char* buf, size_t nBytes, uint flags);
622  static int timeout(int fd, long timeout);
623  static int listen(int fd, int count);
624  static int connect(int fd, struct sockaddr* him, socklen_t len);
625  static int bind(int fd, struct sockaddr* him, socklen_t len);
626  static int accept(int fd, struct sockaddr* him, socklen_t* len);
627  static int recvfrom(int fd, char* buf, size_t nbytes, uint flags,
628                      struct sockaddr* from, socklen_t* fromlen);
629  static int get_sock_name(int fd, struct sockaddr* him, socklen_t* len);
630  static int sendto(int fd, char* buf, size_t len, uint flags,
631                    struct sockaddr* to, socklen_t tolen);
632  static int socket_available(int fd, jint* pbytes);
633
634  static int get_sock_opt(int fd, int level, int optname,
635                          char* optval, socklen_t* optlen);
636  static int set_sock_opt(int fd, int level, int optname,
637                          const char* optval, socklen_t optlen);
638  static int get_host_name(char* name, int namelen);
639
640  static struct hostent* get_host_by_name(char* name);
641
642  // Printing 64 bit integers
643  static const char* jlong_format_specifier();
644  static const char* julong_format_specifier();
645
646  // Support for signals (see JVM_RaiseSignal, JVM_RegisterSignal)
647  static void  signal_init();
648  static void  signal_init_pd();
649  static void  signal_notify(int signal_number);
650  static void* signal(int signal_number, void* handler);
651  static void  signal_raise(int signal_number);
652  static int   signal_wait();
653  static int   signal_lookup();
654  static void* user_handler();
655  static void  terminate_signal_thread();
656  static int   sigexitnum_pd();
657
658  // random number generation
659  static long random();                    // return 32bit pseudorandom number
660  static void init_random(long initval);   // initialize random sequence
661
662  // Structured OS Exception support
663  static void os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, JavaCallArguments* args, Thread* thread);
664
665  // On Windows this will create an actual minidump, on Linux/Solaris it will simply check core dump limits
666  static void check_or_create_dump(void* exceptionRecord, void* contextRecord, char* buffer, size_t bufferSize);
667
668  // Get the default path to the core file
669  // Returns the length of the string
670  static int get_core_path(char* buffer, size_t bufferSize);
671
672  // JVMTI & JVM monitoring and management support
673  // The thread_cpu_time() and current_thread_cpu_time() are only
674  // supported if is_thread_cpu_time_supported() returns true.
675  // They are not supported on Solaris T1.
676
677  // Thread CPU Time - return the fast estimate on a platform
678  // On Solaris - call gethrvtime (fast) - user time only
679  // On Linux   - fast clock_gettime where available - user+sys
680  //            - otherwise: very slow /proc fs - user+sys
681  // On Windows - GetThreadTimes - user+sys
682  static jlong current_thread_cpu_time();
683  static jlong thread_cpu_time(Thread* t);
684
685  // Thread CPU Time with user_sys_cpu_time parameter.
686  //
687  // If user_sys_cpu_time is true, user+sys time is returned.
688  // Otherwise, only user time is returned
689  static jlong current_thread_cpu_time(bool user_sys_cpu_time);
690  static jlong thread_cpu_time(Thread* t, bool user_sys_cpu_time);
691
692  // Return a bunch of info about the timers.
693  // Note that the returned info for these two functions may be different
694  // on some platforms
695  static void current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr);
696  static void thread_cpu_time_info(jvmtiTimerInfo *info_ptr);
697
698  static bool is_thread_cpu_time_supported();
699
700  // System loadavg support.  Returns -1 if load average cannot be obtained.
701  static int loadavg(double loadavg[], int nelem);
702
703  // Hook for os specific jvm options that we don't want to abort on seeing
704  static bool obsolete_option(const JavaVMOption *option);
705
706  // Read file line by line. If line is longer than bsize,
707  // rest of line is skipped. Returns number of bytes read or -1 on EOF
708  static int get_line_chars(int fd, char *buf, const size_t bsize);
709
710  // Extensions
711#include "runtime/os_ext.hpp"
712
713 public:
714
715  // Platform dependent stuff
716#ifdef TARGET_OS_FAMILY_linux
717# include "os_linux.hpp"
718# include "os_posix.hpp"
719#endif
720#ifdef TARGET_OS_FAMILY_solaris
721# include "os_solaris.hpp"
722# include "os_posix.hpp"
723#endif
724#ifdef TARGET_OS_FAMILY_windows
725# include "os_windows.hpp"
726#endif
727#ifdef TARGET_OS_FAMILY_bsd
728# include "os_posix.hpp"
729# include "os_bsd.hpp"
730#endif
731#ifdef TARGET_OS_ARCH_linux_x86
732# include "os_linux_x86.hpp"
733#endif
734#ifdef TARGET_OS_ARCH_linux_sparc
735# include "os_linux_sparc.hpp"
736#endif
737#ifdef TARGET_OS_ARCH_linux_zero
738# include "os_linux_zero.hpp"
739#endif
740#ifdef TARGET_OS_ARCH_solaris_x86
741# include "os_solaris_x86.hpp"
742#endif
743#ifdef TARGET_OS_ARCH_solaris_sparc
744# include "os_solaris_sparc.hpp"
745#endif
746#ifdef TARGET_OS_ARCH_windows_x86
747# include "os_windows_x86.hpp"
748#endif
749#ifdef TARGET_OS_ARCH_linux_arm
750# include "os_linux_arm.hpp"
751#endif
752#ifdef TARGET_OS_ARCH_linux_ppc
753# include "os_linux_ppc.hpp"
754#endif
755#ifdef TARGET_OS_ARCH_bsd_x86
756# include "os_bsd_x86.hpp"
757#endif
758#ifdef TARGET_OS_ARCH_bsd_zero
759# include "os_bsd_zero.hpp"
760#endif
761
762 public:
763  // debugging support (mostly used by debug.cpp but also fatal error handler)
764  static bool find(address pc, outputStream* st = tty); // OS specific function to make sense out of an address
765
766  static bool dont_yield();                     // when true, JVM_Yield() is nop
767  static void print_statistics();
768
769  // Thread priority helpers (implemented in OS-specific part)
770  static OSReturn set_native_priority(Thread* thread, int native_prio);
771  static OSReturn get_native_priority(const Thread* const thread, int* priority_ptr);
772  static int java_to_os_priority[CriticalPriority + 1];
773  // Hint to the underlying OS that a task switch would not be good.
774  // Void return because it's a hint and can fail.
775  static void hint_no_preempt();
776
777  // Used at creation if requested by the diagnostic flag PauseAtStartup.
778  // Causes the VM to wait until an external stimulus has been applied
779  // (for Unix, that stimulus is a signal, for Windows, an external
780  // ResumeThread call)
781  static void pause();
782
783 protected:
784  static long _rand_seed;                   // seed for random number generator
785  static int _processor_count;              // number of processors
786
787  static char* format_boot_path(const char* format_string,
788                                const char* home,
789                                int home_len,
790                                char fileSep,
791                                char pathSep);
792  static bool set_boot_path(char fileSep, char pathSep);
793  static char** split_path(const char* path, int* n);
794};
795
796// Note that "PAUSE" is almost always used with synchronization
797// so arguably we should provide Atomic::SpinPause() instead
798// of the global SpinPause() with C linkage.
799// It'd also be eligible for inlining on many platforms.
800
801extern "C" int SpinPause () ;
802extern "C" int SafeFetch32 (int * adr, int errValue) ;
803extern "C" intptr_t SafeFetchN (intptr_t * adr, intptr_t errValue) ;
804
805#endif // SHARE_VM_RUNTIME_OS_HPP
806