1 /*
2 * Copyright (c) 1997, 2020, 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_RUNTIME_OS_HPP
26 #define SHARE_RUNTIME_OS_HPP
27
28 #include "jvm.h"
29 #include "jvmtifiles/jvmti.h"
30 #include "metaprogramming/isRegisteredEnum.hpp"
31 #include "metaprogramming/integralConstant.hpp"
32 #include "runtime/extendedPC.hpp"
33 #include "utilities/exceptions.hpp"
34 #include "utilities/ostream.hpp"
35 #include "utilities/macros.hpp"
36 #ifndef _WINDOWS
37 # include <setjmp.h>
38 #endif
39 #ifdef __APPLE__
40 # include <mach/mach_time.h>
41 #endif
42
43 class AgentLibrary;
44 class frame;
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
50 class Thread;
51 class JavaThread;
52 class NativeCallStack;
53 class methodHandle;
54 class OSThread;
55 class Mutex;
56
57 template<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
62 enum 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
71 enum 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 // Executable parameter flag for os::commit_memory() and
82 // os::commit_memory_or_exit().
83 const bool ExecMem = true;
84
85 // Typedef for structured exception handling support
86 typedef void (*java_call_t)(JavaValue* value, const methodHandle& method, JavaCallArguments* args, Thread* thread);
87
88 class MallocTracker;
89
90 class os: AllStatic {
91 friend class VMStructs;
92 friend class JVMCIVMStructs;
93 friend class MallocTracker;
94
95 #ifdef ASSERT
96 private:
97 static bool _mutex_init_done;
98 public:
99 static void set_mutex_init_done() { _mutex_init_done = true; }
100 static bool mutex_init_done() { return _mutex_init_done; }
101 #endif
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 public:
110 static size_t _page_sizes[page_sizes_max];
111
112 private:
113 static void init_page_sizes(size_t default_page_size) {
114 _page_sizes[0] = default_page_size;
115 _page_sizes[1] = 0; // sentinel
116 }
117
118 static char* pd_reserve_memory(size_t bytes, char* addr = 0,
119 size_t alignment_hint = 0);
120 static char* pd_attempt_reserve_memory_at(size_t bytes, char* addr);
121 static char* pd_attempt_reserve_memory_at(size_t bytes, char* addr, int file_desc);
122 static bool pd_commit_memory(char* addr, size_t bytes, bool executable);
123 static bool pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
124 bool executable);
125 // Same as pd_commit_memory() that either succeeds or calls
126 // vm_exit_out_of_memory() with the specified mesg.
127 static void pd_commit_memory_or_exit(char* addr, size_t bytes,
128 bool executable, const char* mesg);
129 static void pd_commit_memory_or_exit(char* addr, size_t size,
130 size_t alignment_hint,
131 bool executable, const char* mesg);
132 static bool pd_uncommit_memory(char* addr, size_t bytes);
133 static bool pd_release_memory(char* addr, size_t bytes);
134
135 static char* pd_map_memory(int fd, const char* file_name, size_t file_offset,
136 char *addr, size_t bytes, bool read_only = false,
137 bool allow_exec = false);
138 static char* pd_remap_memory(int fd, const char* file_name, size_t file_offset,
139 char *addr, size_t bytes, bool read_only,
140 bool allow_exec);
141 static bool pd_unmap_memory(char *addr, size_t bytes);
142 static void pd_free_memory(char *addr, size_t bytes, size_t alignment_hint);
143 static void pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint);
144
145 static char* pd_reserve_memory_special(size_t size, size_t alignment,
146 char* addr, bool executable);
147 static bool pd_release_memory_special(char* addr, size_t bytes);
148
149 static size_t page_size_for_region(size_t region_size, size_t min_pages, bool must_be_aligned);
150
151 // Get summary strings for system information in buffer provided
152 static void get_summary_cpu_info(char* buf, size_t buflen);
153 static void get_summary_os_info(char* buf, size_t buflen);
154
155 static void initialize_initial_active_processor_count();
156
157 LINUX_ONLY(static void pd_init_container_support();)
158
159 public:
160 static void init(void); // Called before command line parsing
161
162 static void init_container_support() { // Called during command line parsing.
163 LINUX_ONLY(pd_init_container_support();)
164 }
165
166 static void init_before_ergo(void); // Called after command line parsing
167 // before VM ergonomics processing.
168 static jint init_2(void); // Called after command line parsing
169 // and VM ergonomics processing
170
171 // unset environment variable
172 static bool unsetenv(const char* name);
173
174 static bool have_special_privileges();
175
176 static jlong javaTimeMillis();
177 static jlong javaTimeNanos();
178 static void javaTimeNanos_info(jvmtiTimerInfo *info_ptr);
179 static void javaTimeSystemUTC(jlong &seconds, jlong &nanos);
180 static void run_periodic_checks();
181 static bool supports_monotonic_clock();
182
183 // Returns the elapsed time in seconds since the vm started.
184 static double elapsedTime();
185
186 // Returns real time in seconds since an arbitrary point
187 // in the past.
188 static bool getTimesSecs(double* process_real_time,
189 double* process_user_time,
190 double* process_system_time);
191
192 // Interface to the performance counter
193 static jlong elapsed_counter();
194 static jlong elapsed_frequency();
195
196 // The "virtual time" of a thread is the amount of time a thread has
197 // actually run. The first function indicates whether the OS supports
198 // this functionality for the current thread, and if so the second
199 // returns the elapsed virtual time for the current thread.
200 static bool supports_vtime();
201 static double elapsedVTime();
202
203 // Return current local time in a string (YYYY-MM-DD HH:MM:SS).
204 // It is MT safe, but not async-safe, as reading time zone
205 // information may require a lock on some platforms.
206 static char* local_time_string(char *buf, size_t buflen);
207 static struct tm* localtime_pd (const time_t* clock, struct tm* res);
208 static struct tm* gmtime_pd (const time_t* clock, struct tm* res);
209 // Fill in buffer with current local time as an ISO-8601 string.
210 // E.g., YYYY-MM-DDThh:mm:ss.mmm+zzzz.
211 // Returns buffer, or NULL if it failed.
212 static char* iso8601_time(char* buffer, size_t buffer_length, bool utc = false);
213
214 // Interface for detecting multiprocessor system
215 static inline bool is_MP() {
216 // During bootstrap if _processor_count is not yet initialized
217 // we claim to be MP as that is safest. If any platform has a
218 // stub generator that might be triggered in this phase and for
219 // which being declared MP when in fact not, is a problem - then
220 // the bootstrap routine for the stub generator needs to check
221 // the processor count directly and leave the bootstrap routine
222 // in place until called after initialization has ocurred.
223 return (_processor_count != 1);
224 }
225
226 static julong available_memory();
227 static julong physical_memory();
228 static bool has_allocatable_memory_limit(julong* limit);
229 static bool is_server_class_machine();
230
231 // Returns the id of the processor on which the calling thread is currently executing.
232 // The returned value is guaranteed to be between 0 and (os::processor_count() - 1).
233 static uint processor_id();
234
235 // number of CPUs
236 static int processor_count() {
237 return _processor_count;
238 }
239 static void set_processor_count(int count) { _processor_count = count; }
240
241 // Returns the number of CPUs this process is currently allowed to run on.
242 // Note that on some OSes this can change dynamically.
243 static int active_processor_count();
244
245 // At startup the number of active CPUs this process is allowed to run on.
246 // This value does not change dynamically. May be different from active_processor_count().
247 static int initial_active_processor_count() {
248 assert(_initial_active_processor_count > 0, "Initial active processor count not set yet.");
249 return _initial_active_processor_count;
250 }
251
252 // Binds the current process to a processor.
253 // Returns true if it worked, false if it didn't.
254 static bool bind_to_processor(uint processor_id);
255
256 // Give a name to the current thread.
257 static void set_native_thread_name(const char *name);
258
259 // Interface for stack banging (predetect possible stack overflow for
260 // exception processing) There are guard pages, and above that shadow
261 // pages for stack overflow checking.
262 static bool uses_stack_guard_pages();
263 static bool must_commit_stack_guard_pages();
264 static void map_stack_shadow_pages(address sp);
265 static bool stack_shadow_pages_available(Thread *thread, const methodHandle& method, address sp);
266
267 // Find committed memory region within specified range (start, start + size),
268 // return true if found any
269 static bool committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size);
270
271 // OS interface to Virtual Memory
272
273 // Return the default page size.
274 static int vm_page_size();
275
276 // Returns the page size to use for a region of memory.
277 // region_size / min_pages will always be greater than or equal to the
278 // returned value. The returned value will divide region_size.
279 static size_t page_size_for_region_aligned(size_t region_size, size_t min_pages);
280
281 // Returns the page size to use for a region of memory.
282 // region_size / min_pages will always be greater than or equal to the
283 // returned value. The returned value might not divide region_size.
284 static size_t page_size_for_region_unaligned(size_t region_size, size_t min_pages);
285
286 // Return the largest page size that can be used
287 static size_t max_page_size() {
288 // The _page_sizes array is sorted in descending order.
289 return _page_sizes[0];
290 }
291
292 // Return a lower bound for page sizes. Also works before os::init completed.
293 static size_t min_page_size() { return 4 * K; }
294
295 // Methods for tracing page sizes returned by the above method.
296 // The region_{min,max}_size parameters should be the values
297 // passed to page_size_for_region() and page_size should be the result of that
298 // call. The (optional) base and size parameters should come from the
299 // ReservedSpace base() and size() methods.
300 static void trace_page_sizes(const char* str, const size_t* page_sizes, int count);
301 static void trace_page_sizes(const char* str,
302 const size_t region_min_size,
303 const size_t region_max_size,
304 const size_t page_size,
305 const char* base,
306 const size_t size);
307 static void trace_page_sizes_for_requested_size(const char* str,
308 const size_t requested_size,
309 const size_t page_size,
310 const size_t alignment,
311 const char* base,
312 const size_t size);
313
314 static int vm_allocation_granularity();
315 static char* reserve_memory(size_t bytes, char* addr = 0,
316 size_t alignment_hint = 0, int file_desc = -1);
317 static char* reserve_memory(size_t bytes, char* addr,
318 size_t alignment_hint, MEMFLAGS flags);
319 static char* reserve_memory_aligned(size_t size, size_t alignment, int file_desc = -1);
320 static char* attempt_reserve_memory_at(size_t bytes, char* addr, int file_desc = -1);
321
322
323 // Split a reserved memory region [base, base+size) into two regions [base, base+split) and
324 // [base+split, base+size).
325 // This may remove the original mapping, so its content may be lost.
326 // Both base and split point must be aligned to allocation granularity; split point shall
327 // be >0 and <size.
328 // Splitting guarantees that the resulting two memory regions can be released independently
329 // from each other using os::release_memory().
330 static void split_reserved_memory(char *base, size_t size, size_t split);
331
332 static bool commit_memory(char* addr, size_t bytes, bool executable);
333 static bool commit_memory(char* addr, size_t size, size_t alignment_hint,
334 bool executable);
335 // Same as commit_memory() that either succeeds or calls
336 // vm_exit_out_of_memory() with the specified mesg.
337 static void commit_memory_or_exit(char* addr, size_t bytes,
338 bool executable, const char* mesg);
339 static void commit_memory_or_exit(char* addr, size_t size,
340 size_t alignment_hint,
341 bool executable, const char* mesg);
342 static bool uncommit_memory(char* addr, size_t bytes);
343 static bool release_memory(char* addr, size_t bytes);
344
345 // Touch memory pages that cover the memory range from start to end (exclusive)
346 // to make the OS back the memory range with actual memory.
347 // Current implementation may not touch the last page if unaligned addresses
348 // are passed.
349 static void pretouch_memory(void* start, void* end, size_t page_size = vm_page_size());
350
351 enum ProtType { MEM_PROT_NONE, MEM_PROT_READ, MEM_PROT_RW, MEM_PROT_RWX };
352 static bool protect_memory(char* addr, size_t bytes, ProtType prot,
353 bool is_committed = true);
354
355 static bool guard_memory(char* addr, size_t bytes);
356 static bool unguard_memory(char* addr, size_t bytes);
357 static bool create_stack_guard_pages(char* addr, size_t bytes);
358 static bool pd_create_stack_guard_pages(char* addr, size_t bytes);
359 static bool remove_stack_guard_pages(char* addr, size_t bytes);
360 // Helper function to create a new file with template jvmheap.XXXXXX.
361 // Returns a valid fd on success or else returns -1
362 static int create_file_for_heap(const char* dir);
363 // Map memory to the file referred by fd. This function is slightly different from map_memory()
364 // and is added to be used for implementation of -XX:AllocateHeapAt
365 static char* map_memory_to_file(char* base, size_t size, int fd);
366 // Replace existing reserved memory with file mapping
367 static char* replace_existing_mapping_with_file_mapping(char* base, size_t size, int fd);
368
369 static char* map_memory(int fd, const char* file_name, size_t file_offset,
370 char *addr, size_t bytes, bool read_only = false,
371 bool allow_exec = false);
372 static char* remap_memory(int fd, const char* file_name, size_t file_offset,
373 char *addr, size_t bytes, bool read_only,
374 bool allow_exec);
375 static bool unmap_memory(char *addr, size_t bytes);
376 static void free_memory(char *addr, size_t bytes, size_t alignment_hint);
377 static void realign_memory(char *addr, size_t bytes, size_t alignment_hint);
378
379 // NUMA-specific interface
380 static bool numa_has_static_binding();
381 static bool numa_has_group_homing();
382 static void numa_make_local(char *addr, size_t bytes, int lgrp_hint);
383 static void numa_make_global(char *addr, size_t bytes);
384 static size_t numa_get_groups_num();
385 static size_t numa_get_leaf_groups(int *ids, size_t size);
386 static bool numa_topology_changed();
387 static int numa_get_group_id();
388 static int numa_get_group_id_for_address(const void* address);
389
390 // Page manipulation
391 struct page_info {
392 size_t size;
393 int lgrp_id;
394 };
395 static bool get_page_info(char *start, page_info* info);
396 static char* scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found);
397
398 static char* non_memory_address_word();
399 // reserve, commit and pin the entire memory region
400 static char* reserve_memory_special(size_t size, size_t alignment,
401 char* addr, bool executable);
402 static bool release_memory_special(char* addr, size_t bytes);
403 static void large_page_init();
404 static size_t large_page_size();
405 static bool can_commit_large_page_memory();
406 static bool can_execute_large_page_memory();
407
408 // Check if pointer points to readable memory (by 4-byte read access)
409 static bool is_readable_pointer(const void* p);
410 static bool is_readable_range(const void* from, const void* to);
411
412 // threads
413
414 enum ThreadType {
415 vm_thread,
416 cgc_thread, // Concurrent GC thread
417 pgc_thread, // Parallel GC thread
418 java_thread, // Java, CodeCacheSweeper, JVMTIAgent and Service threads.
419 compiler_thread,
420 watcher_thread,
421 os_thread
422 };
423
424 static bool create_thread(Thread* thread,
425 ThreadType thr_type,
426 size_t req_stack_size = 0);
427
428 // The "main thread", also known as "starting thread", is the thread
429 // that loads/creates the JVM via JNI_CreateJavaVM.
430 static bool create_main_thread(JavaThread* thread);
431
432 // The primordial thread is the initial process thread. The java
433 // launcher never uses the primordial thread as the main thread, but
434 // applications that host the JVM directly may do so. Some platforms
435 // need special-case handling of the primordial thread if it attaches
436 // to the VM.
437 static bool is_primordial_thread(void)
438 #if defined(_WINDOWS) || defined(BSD)
439 // No way to identify the primordial thread.
440 { return false; }
441 #else
442 ;
443 #endif
444
445 static bool create_attached_thread(JavaThread* thread);
446 static void pd_start_thread(Thread* thread);
447 static void start_thread(Thread* thread);
448
449 // Returns true if successful.
450 static bool signal_thread(Thread* thread, int sig, const char* reason);
451
452 static void free_thread(OSThread* osthread);
453
454 // thread id on Linux/64bit is 64bit, on Windows and Solaris, it's 32bit
455 static intx current_thread_id();
456 static int current_process_id();
457
458 // Short standalone OS sleep routines suitable for slow path spin loop.
459 // Ignores safepoints/suspension/Thread.interrupt() (so keep it short).
460 // ms/ns = 0, will sleep for the least amount of time allowed by the OS.
461 // Maximum sleep time is just under 1 second.
462 static void naked_short_sleep(jlong ms);
463 static void naked_short_nanosleep(jlong ns);
464 // Longer standalone OS sleep routine - a convenience wrapper around
465 // multiple calls to naked_short_sleep. Only for use by non-JavaThreads.
466 static void naked_sleep(jlong millis);
467 // Never returns, use with CAUTION
468 static void infinite_sleep();
469 static void naked_yield () ;
470 static OSReturn set_priority(Thread* thread, ThreadPriority priority);
471 static OSReturn get_priority(const Thread* const thread, ThreadPriority& priority);
472
473 static int pd_self_suspend_thread(Thread* thread);
474
475 static ExtendedPC fetch_frame_from_context(const void* ucVoid, intptr_t** sp, intptr_t** fp);
476 static frame fetch_frame_from_context(const void* ucVoid);
477 static frame fetch_frame_from_ucontext(Thread* thread, void* ucVoid);
478
479 static void breakpoint();
480 static bool start_debugging(char *buf, int buflen);
481
482 static address current_stack_pointer();
483 static address current_stack_base();
484 static size_t current_stack_size();
485
486 static void verify_stack_alignment() PRODUCT_RETURN;
487
488 static bool message_box(const char* title, const char* message);
489
490 // run cmd in a separate process and return its exit code; or -1 on failures
491 static int fork_and_exec(char *cmd, bool use_vfork_if_available = false);
492
493 // Call ::exit() on all platforms but Windows
494 static void exit(int num);
495
496 // Terminate the VM, but don't exit the process
497 static void shutdown();
498
499 // Terminate with an error. Default is to generate a core file on platforms
500 // that support such things. This calls shutdown() and then aborts.
501 static void abort(bool dump_core, void *siginfo, const void *context);
502 static void abort(bool dump_core = true);
503
504 // Die immediately, no exit hook, no abort hook, no cleanup.
505 // Dump a core file, if possible, for debugging. os::abort() is the
506 // preferred means to abort the VM on error. os::die() should only
507 // be called if something has gone badly wrong. CreateCoredumpOnCrash
508 // is intentionally not honored by this function.
509 static void die();
510
511 // File i/o operations
512 static int open(const char *path, int oflag, int mode);
513 static FILE* open(int fd, const char* mode);
514 static FILE* fopen(const char* path, const char* mode);
515 static int close(int fd);
516 static jlong lseek(int fd, jlong offset, int whence);
517 // This function, on Windows, canonicalizes a given path (see os_windows.cpp for details).
518 // On Posix, this function is a noop: it does not change anything and just returns
519 // the input pointer.
520 static char* native_path(char *path);
521 static int ftruncate(int fd, jlong length);
522 static int fsync(int fd);
523 static int available(int fd, jlong *bytes);
524 static int get_fileno(FILE* fp);
525 static void flockfile(FILE* fp);
526 static void funlockfile(FILE* fp);
527
528 static int compare_file_modified_times(const char* file1, const char* file2);
529
530 static bool same_files(const char* file1, const char* file2);
531
532 //File i/o operations
533
534 static ssize_t read(int fd, void *buf, unsigned int nBytes);
535 static ssize_t read_at(int fd, void *buf, unsigned int nBytes, jlong offset);
536 static size_t write(int fd, const void *buf, unsigned int nBytes);
537
538 // Reading directories.
539 static DIR* opendir(const char* dirname);
540 static struct dirent* readdir(DIR* dirp);
541 static int closedir(DIR* dirp);
542
543 // Dynamic library extension
544 static const char* dll_file_extension();
545
546 static const char* get_temp_directory();
547 static const char* get_current_directory(char *buf, size_t buflen);
548
549 // Builds the platform-specific name of a library.
550 // Returns false if the buffer is too small.
551 static bool dll_build_name(char* buffer, size_t size,
552 const char* fname);
553
554 // Builds a platform-specific full library path given an ld path and
555 // unadorned library name. Returns true if the buffer contains a full
556 // path to an existing file, false otherwise. If pathname is empty,
557 // uses the path to the current directory.
558 static bool dll_locate_lib(char* buffer, size_t size,
559 const char* pathname, const char* fname);
560
561 // Symbol lookup, find nearest function name; basically it implements
562 // dladdr() for all platforms. Name of the nearest function is copied
563 // to buf. Distance from its base address is optionally returned as offset.
564 // If function name is not found, buf[0] is set to '\0' and offset is
565 // set to -1 (if offset is non-NULL).
566 static bool dll_address_to_function_name(address addr, char* buf,
567 int buflen, int* offset,
568 bool demangle = true);
569
570 // Locate DLL/DSO. On success, full path of the library is copied to
571 // buf, and offset is optionally set to be the distance between addr
572 // and the library's base address. On failure, buf[0] is set to '\0'
573 // and offset is set to -1 (if offset is non-NULL).
574 static bool dll_address_to_library_name(address addr, char* buf,
575 int buflen, int* offset);
576
577 // Find out whether the pc is in the static code for jvm.dll/libjvm.so.
578 static bool address_is_in_vm(address addr);
579
580 // Loads .dll/.so and
581 // in case of error it checks if .dll/.so was built for the
582 // same architecture as HotSpot is running on
583 // in case of an error NULL is returned and an error message is stored in ebuf
584 static void* dll_load(const char *name, char *ebuf, int ebuflen);
585
586 // lookup symbol in a shared library
587 static void* dll_lookup(void* handle, const char* name);
588
589 // Unload library
590 static void dll_unload(void *lib);
591
592 // Callback for loaded module information
593 // Input parameters:
594 // char* module_file_name,
595 // address module_base_addr,
596 // address module_top_addr,
597 // void* param
598 typedef int (*LoadedModulesCallbackFunc)(const char *, address, address, void *);
599
600 static int get_loaded_modules_info(LoadedModulesCallbackFunc callback, void *param);
601
602 // Return the handle of this process
603 static void* get_default_process_handle();
604
605 // Check for static linked agent library
606 static bool find_builtin_agent(AgentLibrary *agent_lib, const char *syms[],
607 size_t syms_len);
608
609 // Find agent entry point
610 static void *find_agent_function(AgentLibrary *agent_lib, bool check_lib,
611 const char *syms[], size_t syms_len);
612
613 // Provide C99 compliant versions of these functions, since some versions
614 // of some platforms don't.
615 static int vsnprintf(char* buf, size_t len, const char* fmt, va_list args) ATTRIBUTE_PRINTF(3, 0);
616 static int snprintf(char* buf, size_t len, const char* fmt, ...) ATTRIBUTE_PRINTF(3, 4);
617
618 // Get host name in buffer provided
619 static bool get_host_name(char* buf, size_t buflen);
620
621 // Print out system information; they are called by fatal error handler.
622 // Output format may be different on different platforms.
623 static void print_os_info(outputStream* st);
624 static void print_os_info_brief(outputStream* st);
625 static void print_cpu_info(outputStream* st, char* buf, size_t buflen);
626 static void pd_print_cpu_info(outputStream* st, char* buf, size_t buflen);
627 static void print_summary_info(outputStream* st, char* buf, size_t buflen);
628 static void print_memory_info(outputStream* st);
629 static void print_dll_info(outputStream* st);
630 static void print_environment_variables(outputStream* st, const char** env_list);
631 static void print_context(outputStream* st, const void* context);
632 static void print_register_info(outputStream* st, const void* context);
633 static bool signal_sent_by_kill(const void* siginfo);
634 static void print_siginfo(outputStream* st, const void* siginfo);
635 static void print_signal_handlers(outputStream* st, char* buf, size_t buflen);
636 static void print_date_and_time(outputStream* st, char* buf, size_t buflen);
637 static void print_instructions(outputStream* st, address pc, int unitsize);
638
639 // helper for output of seconds in days , hours and months
640 static void print_dhm(outputStream* st, const char* startStr, long sec);
641
642 static void print_location(outputStream* st, intptr_t x, bool verbose = false);
643 static size_t lasterror(char *buf, size_t len);
644 static int get_last_error();
645
646 // Replacement for strerror().
647 // Will return the english description of the error (e.g. "File not found", as
648 // suggested in the POSIX standard.
649 // Will return "Unknown error" for an unknown errno value.
650 // Will not attempt to localize the returned string.
651 // Will always return a valid string which is a static constant.
652 // Will not change the value of errno.
653 static const char* strerror(int e);
654
655 // Will return the literalized version of the given errno (e.g. "EINVAL"
656 // for EINVAL).
657 // Will return "Unknown error" for an unknown errno value.
658 // Will always return a valid string which is a static constant.
659 // Will not change the value of errno.
660 static const char* errno_name(int e);
661
662 // wait for a key press if PauseAtExit is set
663 static void wait_for_keypress_at_exit(void);
664
665 // The following two functions are used by fatal error handler to trace
666 // native (C) frames. They are not part of frame.hpp/frame.cpp because
667 // frame.hpp/cpp assume thread is JavaThread, and also because different
668 // OS/compiler may have different convention or provide different API to
669 // walk C frames.
670 //
671 // We don't attempt to become a debugger, so we only follow frames if that
672 // does not require a lookup in the unwind table, which is part of the binary
673 // file but may be unsafe to read after a fatal error. So on x86, we can
674 // only walk stack if %ebp is used as frame pointer; on ia64, it's not
675 // possible to walk C stack without having the unwind table.
676 static bool is_first_C_frame(frame *fr);
677 static frame get_sender_for_C_frame(frame *fr);
678
679 // return current frame. pc() and sp() are set to NULL on failure.
680 static frame current_frame();
681
682 static void print_hex_dump(outputStream* st, address start, address end, int unitsize);
683
684 // returns a string to describe the exception/signal;
685 // returns NULL if exception_code is not an OS exception/signal.
686 static const char* exception_name(int exception_code, char* buf, size_t buflen);
687
688 // Returns the signal number (e.g. 11) for a given signal name (SIGSEGV).
689 static int get_signal_number(const char* signal_name);
690
691 // Returns native Java library, loads if necessary
692 static void* native_java_library();
693
694 // Fills in path to jvm.dll/libjvm.so (used by the Disassembler)
695 static void jvm_path(char *buf, jint buflen);
696
697 // JNI names
698 static void print_jni_name_prefix_on(outputStream* st, int args_size);
699 static void print_jni_name_suffix_on(outputStream* st, int args_size);
700
701 // Init os specific system properties values
702 static void init_system_properties_values();
703
704 // IO operations, non-JVM_ version.
705 static int stat(const char* path, struct stat* sbuf);
706 static bool dir_is_empty(const char* path);
707
708 // IO operations on binary files
709 static int create_binary_file(const char* path, bool rewrite_existing);
710 static jlong current_file_offset(int fd);
711 static jlong seek_to_file_offset(int fd, jlong offset);
712
713 // Retrieve native stack frames.
714 // Parameter:
715 // stack: an array to storage stack pointers.
716 // frames: size of above array.
717 // toSkip: number of stack frames to skip at the beginning.
718 // Return: number of stack frames captured.
719 static int get_native_stack(address* stack, int size, int toSkip = 0);
720
721 // General allocation (must be MT-safe)
722 static void* malloc (size_t size, MEMFLAGS flags, const NativeCallStack& stack);
723 static void* malloc (size_t size, MEMFLAGS flags);
724 static void* realloc (void *memblock, size_t size, MEMFLAGS flag, const NativeCallStack& stack);
725 static void* realloc (void *memblock, size_t size, MEMFLAGS flag);
726
727 // handles NULL pointers
728 static void free (void *memblock);
729 static char* strdup(const char *, MEMFLAGS flags = mtInternal); // Like strdup
730 // Like strdup, but exit VM when strdup() returns NULL
731 static char* strdup_check_oom(const char*, MEMFLAGS flags = mtInternal);
732
733 #ifndef PRODUCT
734 static julong num_mallocs; // # of calls to malloc/realloc
735 static julong alloc_bytes; // # of bytes allocated
736 static julong num_frees; // # of calls to free
737 static julong free_bytes; // # of bytes freed
738 #endif
739
740 // SocketInterface (ex HPI SocketInterface )
741 static int socket(int domain, int type, int protocol);
742 static int socket_close(int fd);
743 static int recv(int fd, char* buf, size_t nBytes, uint flags);
744 static int send(int fd, char* buf, size_t nBytes, uint flags);
745 static int raw_send(int fd, char* buf, size_t nBytes, uint flags);
746 static int connect(int fd, struct sockaddr* him, socklen_t len);
747 static struct hostent* get_host_by_name(char* name);
748
749 // Support for signals (see JVM_RaiseSignal, JVM_RegisterSignal)
750 static void initialize_jdk_signal_support(TRAPS);
751 static void signal_notify(int signal_number);
752 static void* signal(int signal_number, void* handler);
753 static void signal_raise(int signal_number);
754 static int signal_wait();
755 static void* user_handler();
756 static void terminate_signal_thread();
757 static int sigexitnum_pd();
758
759 // random number generation
760 static int random(); // return 32bit pseudorandom number
761 static void init_random(unsigned int initval); // initialize random sequence
762
763 // Structured OS Exception support
764 static void os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, JavaCallArguments* args, Thread* thread);
765
766 // On Posix compatible OS it will simply check core dump limits while on Windows
767 // it will check if dump file can be created. Check or prepare a core dump to be
768 // taken at a later point in the same thread in os::abort(). Use the caller
769 // provided buffer as a scratch buffer. The status message which will be written
770 // into the error log either is file location or a short error message, depending
771 // on the checking result.
772 static void check_dump_limit(char* buffer, size_t bufferSize);
773
774 // Get the default path to the core file
775 // Returns the length of the string
776 static int get_core_path(char* buffer, size_t bufferSize);
777
778 // JVMTI & JVM monitoring and management support
779 // The thread_cpu_time() and current_thread_cpu_time() are only
780 // supported if is_thread_cpu_time_supported() returns true.
781 // They are not supported on Solaris T1.
782
783 // Thread CPU Time - return the fast estimate on a platform
784 // On Solaris - call gethrvtime (fast) - user time only
785 // On Linux - fast clock_gettime where available - user+sys
786 // - otherwise: very slow /proc fs - user+sys
787 // On Windows - GetThreadTimes - user+sys
788 static jlong current_thread_cpu_time();
789 static jlong thread_cpu_time(Thread* t);
790
791 // Thread CPU Time with user_sys_cpu_time parameter.
792 //
793 // If user_sys_cpu_time is true, user+sys time is returned.
794 // Otherwise, only user time is returned
795 static jlong current_thread_cpu_time(bool user_sys_cpu_time);
796 static jlong thread_cpu_time(Thread* t, bool user_sys_cpu_time);
797
798 // Return a bunch of info about the timers.
799 // Note that the returned info for these two functions may be different
800 // on some platforms
801 static void current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr);
802 static void thread_cpu_time_info(jvmtiTimerInfo *info_ptr);
803
804 static bool is_thread_cpu_time_supported();
805
806 // System loadavg support. Returns -1 if load average cannot be obtained.
807 static int loadavg(double loadavg[], int nelem);
808
809 // Amount beyond the callee frame size that we bang the stack.
810 static int extra_bang_size_in_bytes();
811
812 static char** split_path(const char* path, size_t* elements, size_t file_name_length);
813
814 // support for mapping non-volatile memory using MAP_SYNC
815 static bool supports_map_sync();
816
817 public:
818 class CrashProtectionCallback : public StackObj {
819 public:
820 virtual void call() = 0;
821 };
822
823 // Platform dependent stuff
824 #ifndef _WINDOWS
825 # include "os_posix.hpp"
826 #endif
827 #include OS_CPU_HEADER(os)
828 #include OS_HEADER(os)
829
830 #ifndef OS_NATIVE_THREAD_CREATION_FAILED_MSG
831 #define OS_NATIVE_THREAD_CREATION_FAILED_MSG "unable to create native thread: possibly out of memory or process/resource limits reached"
832 #endif
833
834 public:
835 #ifndef PLATFORM_PRINT_NATIVE_STACK
836 // No platform-specific code for printing the native stack.
837 static bool platform_print_native_stack(outputStream* st, const void* context,
838 char *buf, int buf_size) {
839 return false;
840 }
841 #endif
842
843 // debugging support (mostly used by debug.cpp but also fatal error handler)
844 static bool find(address pc, outputStream* st = tty); // OS specific function to make sense out of an address
845
846 static bool dont_yield(); // when true, JVM_Yield() is nop
847 static void print_statistics();
848
849 // Thread priority helpers (implemented in OS-specific part)
850 static OSReturn set_native_priority(Thread* thread, int native_prio);
851 static OSReturn get_native_priority(const Thread* const thread, int* priority_ptr);
852 static int java_to_os_priority[CriticalPriority + 1];
853 // Hint to the underlying OS that a task switch would not be good.
854 // Void return because it's a hint and can fail.
855 static const char* native_thread_creation_failed_msg() {
856 return OS_NATIVE_THREAD_CREATION_FAILED_MSG;
857 }
858
859 // Used at creation if requested by the diagnostic flag PauseAtStartup.
860 // Causes the VM to wait until an external stimulus has been applied
861 // (for Unix, that stimulus is a signal, for Windows, an external
862 // ResumeThread call)
863 static void pause();
864
865 // Builds a platform dependent Agent_OnLoad_<libname> function name
866 // which is used to find statically linked in agents.
867 static char* build_agent_function_name(const char *sym, const char *cname,
868 bool is_absolute_path);
869
870 class SuspendedThreadTaskContext {
871 public:
872 SuspendedThreadTaskContext(Thread* thread, void *ucontext) : _thread(thread), _ucontext(ucontext) {}
873 Thread* thread() const { return _thread; }
874 void* ucontext() const { return _ucontext; }
875 private:
876 Thread* _thread;
877 void* _ucontext;
878 };
879
880 class SuspendedThreadTask {
881 public:
882 SuspendedThreadTask(Thread* thread) : _thread(thread), _done(false) {}
883 void run();
884 bool is_done() { return _done; }
885 virtual void do_task(const SuspendedThreadTaskContext& context) = 0;
886 protected:
887 ~SuspendedThreadTask() {}
888 private:
889 void internal_do_task();
890 Thread* _thread;
891 bool _done;
892 };
893
894 #ifndef _WINDOWS
895 // Suspend/resume support
896 // Protocol:
897 //
898 // a thread starts in SR_RUNNING
899 //
900 // SR_RUNNING can go to
901 // * SR_SUSPEND_REQUEST when the WatcherThread wants to suspend it
902 // SR_SUSPEND_REQUEST can go to
903 // * SR_RUNNING if WatcherThread decides it waited for SR_SUSPENDED too long (timeout)
904 // * SR_SUSPENDED if the stopped thread receives the signal and switches state
905 // SR_SUSPENDED can go to
906 // * SR_WAKEUP_REQUEST when the WatcherThread has done the work and wants to resume
907 // SR_WAKEUP_REQUEST can go to
908 // * SR_RUNNING when the stopped thread receives the signal
909 // * SR_WAKEUP_REQUEST on timeout (resend the signal and try again)
910 class SuspendResume {
911 public:
912 enum State {
913 SR_RUNNING,
914 SR_SUSPEND_REQUEST,
915 SR_SUSPENDED,
916 SR_WAKEUP_REQUEST
917 };
918
919 private:
920 volatile State _state;
921
922 private:
923 /* try to switch state from state "from" to state "to"
924 * returns the state set after the method is complete
925 */
926 State switch_state(State from, State to);
927
928 public:
929 SuspendResume() : _state(SR_RUNNING) { }
930
931 State state() const { return _state; }
932
933 State request_suspend() {
934 return switch_state(SR_RUNNING, SR_SUSPEND_REQUEST);
935 }
936
937 State cancel_suspend() {
938 return switch_state(SR_SUSPEND_REQUEST, SR_RUNNING);
939 }
940
941 State suspended() {
942 return switch_state(SR_SUSPEND_REQUEST, SR_SUSPENDED);
943 }
944
945 State request_wakeup() {
946 return switch_state(SR_SUSPENDED, SR_WAKEUP_REQUEST);
947 }
948
949 State running() {
950 return switch_state(SR_WAKEUP_REQUEST, SR_RUNNING);
951 }
952
953 bool is_running() const {
954 return _state == SR_RUNNING;
955 }
956
957 bool is_suspended() const {
958 return _state == SR_SUSPENDED;
959 }
960 };
961 #endif // !WINDOWS
962
963
964 protected:
965 static volatile unsigned int _rand_seed; // seed for random number generator
966 static int _processor_count; // number of processors
967 static int _initial_active_processor_count; // number of active processors during initialization.
968
969 static char* format_boot_path(const char* format_string,
970 const char* home,
971 int home_len,
972 char fileSep,
973 char pathSep);
974 static bool set_boot_path(char fileSep, char pathSep);
975
976 };
977
978 #ifndef _WINDOWS
979 template<> struct IsRegisteredEnum<os::SuspendResume::State> : public TrueType {};
980 #endif // !_WINDOWS
981
982 // Note that "PAUSE" is almost always used with synchronization
983 // so arguably we should provide Atomic::SpinPause() instead
984 // of the global SpinPause() with C linkage.
985 // It'd also be eligible for inlining on many platforms.
986
987 extern "C" int SpinPause();
988
989 #endif // SHARE_RUNTIME_OS_HPP