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 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/moduleEntry.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "classfile/vmSymbols.hpp"
32 #include "code/codeCache.hpp"
33 #include "code/icBuffer.hpp"
34 #include "code/vtableStubs.hpp"
35 #include "gc/shared/gcVMOperations.hpp"
36 #include "logging/log.hpp"
37 #include "interpreter/interpreter.hpp"
38 #include "logging/log.hpp"
39 #include "logging/logStream.hpp"
40 #include "memory/allocation.inline.hpp"
41 #include "memory/guardedMemory.hpp"
42 #include "memory/resourceArea.hpp"
43 #include "memory/universe.hpp"
44 #include "oops/compressedOops.inline.hpp"
45 #include "oops/oop.inline.hpp"
46 #include "prims/jvm_misc.hpp"
47 #include "runtime/arguments.hpp"
48 #include "runtime/atomic.hpp"
49 #include "runtime/frame.inline.hpp"
50 #include "runtime/handles.inline.hpp"
51 #include "runtime/interfaceSupport.inline.hpp"
52 #include "runtime/java.hpp"
53 #include "runtime/javaCalls.hpp"
54 #include "runtime/mutexLocker.hpp"
55 #include "runtime/os.inline.hpp"
56 #include "runtime/sharedRuntime.hpp"
57 #include "runtime/stubRoutines.hpp"
58 #include "runtime/thread.inline.hpp"
59 #include "runtime/threadSMR.hpp"
60 #include "runtime/vm_version.hpp"
61 #include "services/attachListener.hpp"
62 #include "services/mallocTracker.hpp"
63 #include "services/memTracker.hpp"
64 #include "services/nmtCommon.hpp"
65 #include "services/threadService.hpp"
66 #include "utilities/align.hpp"
67 #include "utilities/defaultStream.hpp"
68 #include "utilities/events.hpp"
69
70 # include <signal.h>
71 # include <errno.h>
72
73 OSThread* os::_starting_thread = NULL;
74 address os::_polling_page = NULL;
75 volatile unsigned int os::_rand_seed = 1;
76 int os::_processor_count = 0;
77 int os::_initial_active_processor_count = 0;
78 size_t os::_page_sizes[os::page_sizes_max];
79
80 #ifndef PRODUCT
81 julong os::num_mallocs = 0; // # of calls to malloc/realloc
82 julong os::alloc_bytes = 0; // # of bytes allocated
83 julong os::num_frees = 0; // # of calls to free
84 julong os::free_bytes = 0; // # of bytes freed
85 #endif
86
87 static size_t cur_malloc_words = 0; // current size for MallocMaxTestWords
88
89 DEBUG_ONLY(bool os::_mutex_init_done = false;)
90
91 static time_t get_timezone(const struct tm* time_struct) {
92 // seconds to add to local time to get UTC
93 time_t offset;
94
95 #if defined(_ALLBSD_SOURCE)
96 offset = -(time_struct->tm_gmtoff);
97 #elif defined(_WINDOWS)
98 long zone;
99 _get_timezone(&zone);
100 offset = static_cast<time_t>(zone);
101 #else
102 offset = timezone;
103 #endif
104
105 // tm_gmtoff already includes adjustment for daylight saving
106 #if !defined(_ALLBSD_SOURCE)
107 // If daylight savings time is in effect,
108 // we are 1 hour East of our time zone
109 const time_t seconds_per_minute = 60;
110 const time_t minutes_per_hour = 60;
111 const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
112 if (time_struct->tm_isdst > 0) {
113 offset = offset - seconds_per_hour;
114 }
115 #endif
116
117 return offset;
118 }
119
120 int os::snprintf(char* buf, size_t len, const char* fmt, ...) {
121 va_list args;
122 va_start(args, fmt);
123 int result = os::vsnprintf(buf, len, fmt, args);
124 va_end(args);
125 return result;
126 }
127
128 // Fill in buffer with current local time as an ISO-8601 string.
129 // E.g., yyyy-mm-ddThh:mm:ss-zzzz.
130 // Returns buffer, or NULL if it failed.
131 // This would mostly be a call to
132 // strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
133 // except that on Windows the %z behaves badly, so we do it ourselves.
134 // Also, people wanted milliseconds on there,
135 // and strftime doesn't do milliseconds.
136 char* os::iso8601_time(char* buffer, size_t buffer_length, bool utc) {
137 // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
138 // 1 2
139 // 12345678901234567890123456789
140 // format string: "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d"
141 static const size_t needed_buffer = 29;
142
143 // Sanity check the arguments
144 if (buffer == NULL) {
145 assert(false, "NULL buffer");
146 return NULL;
147 }
148 if (buffer_length < needed_buffer) {
149 assert(false, "buffer_length too small");
150 return NULL;
151 }
152 // Get the current time
153 jlong milliseconds_since_19700101 = javaTimeMillis();
154 const int milliseconds_per_microsecond = 1000;
155 const time_t seconds_since_19700101 =
156 milliseconds_since_19700101 / milliseconds_per_microsecond;
157 const int milliseconds_after_second =
158 milliseconds_since_19700101 % milliseconds_per_microsecond;
159 // Convert the time value to a tm and timezone variable
160 struct tm time_struct;
161 if (utc) {
162 if (gmtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
163 assert(false, "Failed gmtime_pd");
164 return NULL;
165 }
166 } else {
167 if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
168 assert(false, "Failed localtime_pd");
169 return NULL;
170 }
171 }
172 time_t UTC_to_local = get_timezone(&time_struct);
173
174 // No offset when dealing with UTC
175 if (utc) {
176 UTC_to_local = 0;
177 }
178
179 // Compute the time zone offset.
180 // localtime_pd() sets timezone to the difference (in seconds)
181 // between UTC and and local time.
182 // ISO 8601 says we need the difference between local time and UTC,
183 // we change the sign of the localtime_pd() result.
184 const time_t local_to_UTC = -(UTC_to_local);
185 // Then we have to figure out if if we are ahead (+) or behind (-) UTC.
186 char sign_local_to_UTC = '+';
187 time_t abs_local_to_UTC = local_to_UTC;
188 if (local_to_UTC < 0) {
189 sign_local_to_UTC = '-';
190 abs_local_to_UTC = -(abs_local_to_UTC);
191 }
192 // Convert time zone offset seconds to hours and minutes.
193 const time_t seconds_per_minute = 60;
194 const time_t minutes_per_hour = 60;
195 const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
196 const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
197 const time_t zone_min =
198 ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
199
200 // Print an ISO 8601 date and time stamp into the buffer
201 const int year = 1900 + time_struct.tm_year;
202 const int month = 1 + time_struct.tm_mon;
203 const int printed = jio_snprintf(buffer, buffer_length,
204 "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d",
205 year,
206 month,
207 time_struct.tm_mday,
208 time_struct.tm_hour,
209 time_struct.tm_min,
210 time_struct.tm_sec,
211 milliseconds_after_second,
212 sign_local_to_UTC,
213 zone_hours,
214 zone_min);
215 if (printed == 0) {
216 assert(false, "Failed jio_printf");
217 return NULL;
218 }
219 return buffer;
220 }
221
222 OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
223 debug_only(Thread::check_for_dangling_thread_pointer(thread);)
224
225 if ((p >= MinPriority && p <= MaxPriority) ||
226 (p == CriticalPriority && thread->is_ConcurrentGC_thread())) {
227 int priority = java_to_os_priority[p];
228 return set_native_priority(thread, priority);
229 } else {
230 assert(false, "Should not happen");
231 return OS_ERR;
232 }
233 }
234
235 // The mapping from OS priority back to Java priority may be inexact because
236 // Java priorities can map M:1 with native priorities. If you want the definite
237 // Java priority then use JavaThread::java_priority()
238 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
239 int p;
240 int os_prio;
241 OSReturn ret = get_native_priority(thread, &os_prio);
242 if (ret != OS_OK) return ret;
243
244 if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) {
245 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
246 } else {
247 // niceness values are in reverse order
248 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] < os_prio; p--) ;
249 }
250 priority = (ThreadPriority)p;
251 return OS_OK;
252 }
253
254 bool os::dll_build_name(char* buffer, size_t size, const char* fname) {
255 int n = jio_snprintf(buffer, size, "%s%s%s", JNI_LIB_PREFIX, fname, JNI_LIB_SUFFIX);
256 return (n != -1);
257 }
258
259 #if !defined(LINUX) && !defined(_WINDOWS)
260 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
261 committed_start = start;
262 committed_size = size;
263 return true;
264 }
265 #endif
266
267 // Helper for dll_locate_lib.
268 // Pass buffer and printbuffer as we already printed the path to buffer
269 // when we called get_current_directory. This way we avoid another buffer
270 // of size MAX_PATH.
271 static bool conc_path_file_and_check(char *buffer, char *printbuffer, size_t printbuflen,
272 const char* pname, char lastchar, const char* fname) {
273
274 // Concatenate path and file name, but don't print double path separators.
275 const char *filesep = (WINDOWS_ONLY(lastchar == ':' ||) lastchar == os::file_separator()[0]) ?
276 "" : os::file_separator();
277 int ret = jio_snprintf(printbuffer, printbuflen, "%s%s%s", pname, filesep, fname);
278 // Check whether file exists.
279 if (ret != -1) {
280 struct stat statbuf;
281 return os::stat(buffer, &statbuf) == 0;
282 }
283 return false;
284 }
285
286 // Frees all memory allocated on the heap for the
287 // supplied array of arrays of chars (a), where n
288 // is the number of elements in the array.
289 static void free_array_of_char_arrays(char** a, size_t n) {
290 while (n > 0) {
291 n--;
292 if (a[n] != NULL) {
293 FREE_C_HEAP_ARRAY(char, a[n]);
294 }
295 }
296 FREE_C_HEAP_ARRAY(char*, a);
297 }
298
299 bool os::dll_locate_lib(char *buffer, size_t buflen,
300 const char* pname, const char* fname) {
301 bool retval = false;
302
303 size_t fullfnamelen = strlen(JNI_LIB_PREFIX) + strlen(fname) + strlen(JNI_LIB_SUFFIX);
304 char* fullfname = NEW_C_HEAP_ARRAY(char, fullfnamelen + 1, mtInternal);
305 if (dll_build_name(fullfname, fullfnamelen + 1, fname)) {
306 const size_t pnamelen = pname ? strlen(pname) : 0;
307
308 if (pnamelen == 0) {
309 // If no path given, use current working directory.
310 const char* p = get_current_directory(buffer, buflen);
311 if (p != NULL) {
312 const size_t plen = strlen(buffer);
313 const char lastchar = buffer[plen - 1];
314 retval = conc_path_file_and_check(buffer, &buffer[plen], buflen - plen,
315 "", lastchar, fullfname);
316 }
317 } else if (strchr(pname, *os::path_separator()) != NULL) {
318 // A list of paths. Search for the path that contains the library.
319 size_t n;
320 char** pelements = split_path(pname, &n, fullfnamelen);
321 if (pelements != NULL) {
322 for (size_t i = 0; i < n; i++) {
323 char* path = pelements[i];
324 // Really shouldn't be NULL, but check can't hurt.
325 size_t plen = (path == NULL) ? 0 : strlen(path);
326 if (plen == 0) {
327 continue; // Skip the empty path values.
328 }
329 const char lastchar = path[plen - 1];
330 retval = conc_path_file_and_check(buffer, buffer, buflen, path, lastchar, fullfname);
331 if (retval) break;
332 }
333 // Release the storage allocated by split_path.
334 free_array_of_char_arrays(pelements, n);
335 }
336 } else {
337 // A definite path.
338 const char lastchar = pname[pnamelen-1];
339 retval = conc_path_file_and_check(buffer, buffer, buflen, pname, lastchar, fullfname);
340 }
341 }
342
343 FREE_C_HEAP_ARRAY(char*, fullfname);
344 return retval;
345 }
346
347 // --------------------- sun.misc.Signal (optional) ---------------------
348
349
350 // SIGBREAK is sent by the keyboard to query the VM state
351 #ifndef SIGBREAK
352 #define SIGBREAK SIGQUIT
353 #endif
354
355 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
356
357
358 static void signal_thread_entry(JavaThread* thread, TRAPS) {
359 os::set_priority(thread, NearMaxPriority);
360 while (true) {
361 int sig;
362 {
363 // FIXME : Currently we have not decided what should be the status
364 // for this java thread blocked here. Once we decide about
365 // that we should fix this.
366 sig = os::signal_wait();
367 }
368 if (sig == os::sigexitnum_pd()) {
369 // Terminate the signal thread
370 return;
371 }
372
373 switch (sig) {
374 case SIGBREAK: {
375 #if INCLUDE_SERVICES
376 // Check if the signal is a trigger to start the Attach Listener - in that
377 // case don't print stack traces.
378 if (!DisableAttachMechanism) {
379 // Attempt to transit state to AL_INITIALIZING.
380 AttachListenerState cur_state = AttachListener::transit_state(AL_INITIALIZING, AL_NOT_INITIALIZED);
381 if (cur_state == AL_INITIALIZING) {
382 // Attach Listener has been started to initialize. Ignore this signal.
383 continue;
384 } else if (cur_state == AL_NOT_INITIALIZED) {
385 // Start to initialize.
386 if (AttachListener::is_init_trigger()) {
387 // Attach Listener has been initialized.
388 // Accept subsequent request.
389 continue;
390 } else {
391 // Attach Listener could not be started.
392 // So we need to transit the state to AL_NOT_INITIALIZED.
393 AttachListener::set_state(AL_NOT_INITIALIZED);
394 }
395 } else if (AttachListener::check_socket_file()) {
396 // Attach Listener has been started, but unix domain socket file
397 // does not exist. So restart Attach Listener.
398 continue;
399 }
400 }
401 #endif
402 // Print stack traces
403 // Any SIGBREAK operations added here should make sure to flush
404 // the output stream (e.g. tty->flush()) after output. See 4803766.
405 // Each module also prints an extra carriage return after its output.
406 VM_PrintThreads op;
407 VMThread::execute(&op);
408 VM_PrintJNI jni_op;
409 VMThread::execute(&jni_op);
410 VM_FindDeadlocks op1(tty);
411 VMThread::execute(&op1);
412 Universe::print_heap_at_SIGBREAK();
413 if (PrintClassHistogram) {
414 VM_GC_HeapInspection op1(tty, true /* force full GC before heap inspection */);
415 VMThread::execute(&op1);
416 }
417 if (JvmtiExport::should_post_data_dump()) {
418 JvmtiExport::post_data_dump();
419 }
420 break;
421 }
422 default: {
423 // Dispatch the signal to java
424 HandleMark hm(THREAD);
425 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_misc_Signal(), THREAD);
426 if (klass != NULL) {
427 JavaValue result(T_VOID);
428 JavaCallArguments args;
429 args.push_int(sig);
430 JavaCalls::call_static(
431 &result,
432 klass,
433 vmSymbols::dispatch_name(),
434 vmSymbols::int_void_signature(),
435 &args,
436 THREAD
437 );
438 }
439 if (HAS_PENDING_EXCEPTION) {
440 // tty is initialized early so we don't expect it to be null, but
441 // if it is we can't risk doing an initialization that might
442 // trigger additional out-of-memory conditions
443 if (tty != NULL) {
444 char klass_name[256];
445 char tmp_sig_name[16];
446 const char* sig_name = "UNKNOWN";
447 InstanceKlass::cast(PENDING_EXCEPTION->klass())->
448 name()->as_klass_external_name(klass_name, 256);
449 if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
450 sig_name = tmp_sig_name;
451 warning("Exception %s occurred dispatching signal %s to handler"
452 "- the VM may need to be forcibly terminated",
453 klass_name, sig_name );
454 }
455 CLEAR_PENDING_EXCEPTION;
456 }
457 }
458 }
459 }
460 }
461
462 void os::init_before_ergo() {
463 initialize_initial_active_processor_count();
464 // We need to initialize large page support here because ergonomics takes some
465 // decisions depending on large page support and the calculated large page size.
466 large_page_init();
467
468 // We need to adapt the configured number of stack protection pages given
469 // in 4K pages to the actual os page size. We must do this before setting
470 // up minimal stack sizes etc. in os::init_2().
471 JavaThread::set_stack_red_zone_size (align_up(StackRedPages * 4 * K, vm_page_size()));
472 JavaThread::set_stack_yellow_zone_size (align_up(StackYellowPages * 4 * K, vm_page_size()));
473 JavaThread::set_stack_reserved_zone_size(align_up(StackReservedPages * 4 * K, vm_page_size()));
474 JavaThread::set_stack_shadow_zone_size (align_up(StackShadowPages * 4 * K, vm_page_size()));
475
476 // VM version initialization identifies some characteristics of the
477 // platform that are used during ergonomic decisions.
478 VM_Version::init_before_ergo();
479 }
480
481 void os::initialize_jdk_signal_support(TRAPS) {
482 if (!ReduceSignalUsage) {
483 // Setup JavaThread for processing signals
484 const char thread_name[] = "Signal Dispatcher";
485 Handle string = java_lang_String::create_from_str(thread_name, CHECK);
486
487 // Initialize thread_oop to put it into the system threadGroup
488 Handle thread_group (THREAD, Universe::system_thread_group());
489 Handle thread_oop = JavaCalls::construct_new_instance(SystemDictionary::Thread_klass(),
490 vmSymbols::threadgroup_string_void_signature(),
491 thread_group,
492 string,
493 CHECK);
494
495 Klass* group = SystemDictionary::ThreadGroup_klass();
496 JavaValue result(T_VOID);
497 JavaCalls::call_special(&result,
498 thread_group,
499 group,
500 vmSymbols::add_method_name(),
501 vmSymbols::thread_void_signature(),
502 thread_oop,
503 CHECK);
504
505 { MutexLocker mu(THREAD, Threads_lock);
506 JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
507
508 // At this point it may be possible that no osthread was created for the
509 // JavaThread due to lack of memory. We would have to throw an exception
510 // in that case. However, since this must work and we do not allow
511 // exceptions anyway, check and abort if this fails.
512 if (signal_thread == NULL || signal_thread->osthread() == NULL) {
513 vm_exit_during_initialization("java.lang.OutOfMemoryError",
514 os::native_thread_creation_failed_msg());
515 }
516
517 java_lang_Thread::set_thread(thread_oop(), signal_thread);
518 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
519 java_lang_Thread::set_daemon(thread_oop());
520
521 signal_thread->set_threadObj(thread_oop());
522 Threads::add(signal_thread);
523 Thread::start(signal_thread);
524 }
525 // Handle ^BREAK
526 os::signal(SIGBREAK, os::user_handler());
527 }
528 }
529
530
531 void os::terminate_signal_thread() {
532 if (!ReduceSignalUsage)
533 signal_notify(sigexitnum_pd());
534 }
535
536
537 // --------------------- loading libraries ---------------------
538
539 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
540 extern struct JavaVM_ main_vm;
541
542 static void* _native_java_library = NULL;
543
544 void* os::native_java_library() {
545 if (_native_java_library == NULL) {
546 char buffer[JVM_MAXPATHLEN];
547 char ebuf[1024];
548
549 // Load java dll
550 if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
551 "java")) {
552 _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
553 }
554 if (_native_java_library == NULL) {
555 vm_exit_during_initialization("Unable to load native library", ebuf);
556 }
557
558 #if defined(__OpenBSD__)
559 // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so
560 // ignore errors
561 if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
562 "net")) {
563 dll_load(buffer, ebuf, sizeof(ebuf));
564 }
565 #endif
566 }
567 return _native_java_library;
568 }
569
570 /*
571 * Support for finding Agent_On(Un)Load/Attach<_lib_name> if it exists.
572 * If check_lib == true then we are looking for an
573 * Agent_OnLoad_lib_name or Agent_OnAttach_lib_name function to determine if
574 * this library is statically linked into the image.
575 * If check_lib == false then we will look for the appropriate symbol in the
576 * executable if agent_lib->is_static_lib() == true or in the shared library
577 * referenced by 'handle'.
578 */
579 void* os::find_agent_function(AgentLibrary *agent_lib, bool check_lib,
580 const char *syms[], size_t syms_len) {
581 assert(agent_lib != NULL, "sanity check");
582 const char *lib_name;
583 void *handle = agent_lib->os_lib();
584 void *entryName = NULL;
585 char *agent_function_name;
586 size_t i;
587
588 // If checking then use the agent name otherwise test is_static_lib() to
589 // see how to process this lookup
590 lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : NULL);
591 for (i = 0; i < syms_len; i++) {
592 agent_function_name = build_agent_function_name(syms[i], lib_name, agent_lib->is_absolute_path());
593 if (agent_function_name == NULL) {
594 break;
595 }
596 entryName = dll_lookup(handle, agent_function_name);
597 FREE_C_HEAP_ARRAY(char, agent_function_name);
598 if (entryName != NULL) {
599 break;
600 }
601 }
602 return entryName;
603 }
604
605 // See if the passed in agent is statically linked into the VM image.
606 bool os::find_builtin_agent(AgentLibrary *agent_lib, const char *syms[],
607 size_t syms_len) {
608 void *ret;
609 void *proc_handle;
610 void *save_handle;
611
612 assert(agent_lib != NULL, "sanity check");
613 if (agent_lib->name() == NULL) {
614 return false;
615 }
616 proc_handle = get_default_process_handle();
617 // Check for Agent_OnLoad/Attach_lib_name function
618 save_handle = agent_lib->os_lib();
619 // We want to look in this process' symbol table.
620 agent_lib->set_os_lib(proc_handle);
621 ret = find_agent_function(agent_lib, true, syms, syms_len);
622 if (ret != NULL) {
623 // Found an entry point like Agent_OnLoad_lib_name so we have a static agent
624 agent_lib->set_valid();
625 agent_lib->set_static_lib(true);
626 return true;
627 }
628 agent_lib->set_os_lib(save_handle);
629 return false;
630 }
631
632 // --------------------- heap allocation utilities ---------------------
633
634 char *os::strdup(const char *str, MEMFLAGS flags) {
635 size_t size = strlen(str);
636 char *dup_str = (char *)malloc(size + 1, flags);
637 if (dup_str == NULL) return NULL;
638 strcpy(dup_str, str);
639 return dup_str;
640 }
641
642 char* os::strdup_check_oom(const char* str, MEMFLAGS flags) {
643 char* p = os::strdup(str, flags);
644 if (p == NULL) {
645 vm_exit_out_of_memory(strlen(str) + 1, OOM_MALLOC_ERROR, "os::strdup_check_oom");
646 }
647 return p;
648 }
649
650
651 #define paranoid 0 /* only set to 1 if you suspect checking code has bug */
652
653 #ifdef ASSERT
654
655 static void verify_memory(void* ptr) {
656 GuardedMemory guarded(ptr);
657 if (!guarded.verify_guards()) {
658 LogTarget(Warning, malloc, free) lt;
659 ResourceMark rm;
660 LogStream ls(lt);
661 ls.print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees);
662 ls.print_cr("## memory stomp:");
663 guarded.print_on(&ls);
664 fatal("memory stomping error");
665 }
666 }
667
668 #endif
669
670 //
671 // This function supports testing of the malloc out of memory
672 // condition without really running the system out of memory.
673 //
674 static bool has_reached_max_malloc_test_peak(size_t alloc_size) {
675 if (MallocMaxTestWords > 0) {
676 size_t words = (alloc_size / BytesPerWord);
677
678 if ((cur_malloc_words + words) > MallocMaxTestWords) {
679 return true;
680 }
681 Atomic::add(&cur_malloc_words, words);
682 }
683 return false;
684 }
685
686 void* os::malloc(size_t size, MEMFLAGS flags) {
687 return os::malloc(size, flags, CALLER_PC);
688 }
689
690 void* os::malloc(size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
691 NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
692 NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
693
694 // Since os::malloc can be called when the libjvm.{dll,so} is
695 // first loaded and we don't have a thread yet we must accept NULL also here.
696 assert(!os::ThreadCrashProtection::is_crash_protected(Thread::current_or_null()),
697 "malloc() not allowed when crash protection is set");
698
699 if (size == 0) {
700 // return a valid pointer if size is zero
701 // if NULL is returned the calling functions assume out of memory.
702 size = 1;
703 }
704
705 // NMT support
706 NMT_TrackingLevel level = MemTracker::tracking_level();
707 size_t nmt_header_size = MemTracker::malloc_header_size(level);
708
709 #ifndef ASSERT
710 const size_t alloc_size = size + nmt_header_size;
711 #else
712 const size_t alloc_size = GuardedMemory::get_total_size(size + nmt_header_size);
713 if (size + nmt_header_size > alloc_size) { // Check for rollover.
714 return NULL;
715 }
716 #endif
717
718 // For the test flag -XX:MallocMaxTestWords
719 if (has_reached_max_malloc_test_peak(size)) {
720 return NULL;
721 }
722
723 u_char* ptr;
724 ptr = (u_char*)::malloc(alloc_size);
725
726 #ifdef ASSERT
727 if (ptr == NULL) {
728 return NULL;
729 }
730 // Wrap memory with guard
731 GuardedMemory guarded(ptr, size + nmt_header_size);
732 ptr = guarded.get_user_ptr();
733
734 if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
735 log_warning(malloc, free)("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
736 breakpoint();
737 }
738 if (paranoid) {
739 verify_memory(ptr);
740 }
741 #endif
742
743 // we do not track guard memory
744 return MemTracker::record_malloc((address)ptr, size, memflags, stack, level);
745 }
746
747 void* os::realloc(void *memblock, size_t size, MEMFLAGS flags) {
748 return os::realloc(memblock, size, flags, CALLER_PC);
749 }
750
751 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
752
753 // For the test flag -XX:MallocMaxTestWords
754 if (has_reached_max_malloc_test_peak(size)) {
755 return NULL;
756 }
757
758 if (size == 0) {
759 // return a valid pointer if size is zero
760 // if NULL is returned the calling functions assume out of memory.
761 size = 1;
762 }
763
764 #ifndef ASSERT
765 NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
766 NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
767 // NMT support
768 NMT_TrackingLevel level = MemTracker::tracking_level();
769 void* membase = MemTracker::record_free(memblock, level);
770 size_t nmt_header_size = MemTracker::malloc_header_size(level);
771 void* ptr = ::realloc(membase, size + nmt_header_size);
772 return MemTracker::record_malloc(ptr, size, memflags, stack, level);
773 #else
774 if (memblock == NULL) {
775 return os::malloc(size, memflags, stack);
776 }
777 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
778 log_warning(malloc, free)("os::realloc caught " PTR_FORMAT, p2i(memblock));
779 breakpoint();
780 }
781 // NMT support
782 void* membase = MemTracker::malloc_base(memblock);
783 verify_memory(membase);
784 // always move the block
785 void* ptr = os::malloc(size, memflags, stack);
786 // Copy to new memory if malloc didn't fail
787 if (ptr != NULL ) {
788 GuardedMemory guarded(MemTracker::malloc_base(memblock));
789 // Guard's user data contains NMT header
790 size_t memblock_size = guarded.get_user_size() - MemTracker::malloc_header_size(memblock);
791 memcpy(ptr, memblock, MIN2(size, memblock_size));
792 if (paranoid) {
793 verify_memory(MemTracker::malloc_base(ptr));
794 }
795 os::free(memblock);
796 }
797 return ptr;
798 #endif
799 }
800
801 // handles NULL pointers
802 void os::free(void *memblock) {
803 NOT_PRODUCT(inc_stat_counter(&num_frees, 1));
804 #ifdef ASSERT
805 if (memblock == NULL) return;
806 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
807 log_warning(malloc, free)("os::free caught " PTR_FORMAT, p2i(memblock));
808 breakpoint();
809 }
810 void* membase = MemTracker::record_free(memblock, MemTracker::tracking_level());
811 verify_memory(membase);
812
813 GuardedMemory guarded(membase);
814 size_t size = guarded.get_user_size();
815 inc_stat_counter(&free_bytes, size);
816 membase = guarded.release_for_freeing();
817 ::free(membase);
818 #else
819 void* membase = MemTracker::record_free(memblock, MemTracker::tracking_level());
820 ::free(membase);
821 #endif
822 }
823
824 void os::init_random(unsigned int initval) {
825 _rand_seed = initval;
826 }
827
828
829 static int random_helper(unsigned int rand_seed) {
830 /* standard, well-known linear congruential random generator with
831 * next_rand = (16807*seed) mod (2**31-1)
832 * see
833 * (1) "Random Number Generators: Good Ones Are Hard to Find",
834 * S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
835 * (2) "Two Fast Implementations of the 'Minimal Standard' Random
836 * Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
837 */
838 const unsigned int a = 16807;
839 const unsigned int m = 2147483647;
840 const int q = m / a; assert(q == 127773, "weird math");
841 const int r = m % a; assert(r == 2836, "weird math");
842
843 // compute az=2^31p+q
844 unsigned int lo = a * (rand_seed & 0xFFFF);
845 unsigned int hi = a * (rand_seed >> 16);
846 lo += (hi & 0x7FFF) << 16;
847
848 // if q overflowed, ignore the overflow and increment q
849 if (lo > m) {
850 lo &= m;
851 ++lo;
852 }
853 lo += hi >> 15;
854
855 // if (p+q) overflowed, ignore the overflow and increment (p+q)
856 if (lo > m) {
857 lo &= m;
858 ++lo;
859 }
860 return lo;
861 }
862
863 int os::random() {
864 // Make updating the random seed thread safe.
865 while (true) {
866 unsigned int seed = _rand_seed;
867 unsigned int rand = random_helper(seed);
868 if (Atomic::cmpxchg(&_rand_seed, seed, rand) == seed) {
869 return static_cast<int>(rand);
870 }
871 }
872 }
873
874 // The INITIALIZED state is distinguished from the SUSPENDED state because the
875 // conditions in which a thread is first started are different from those in which
876 // a suspension is resumed. These differences make it hard for us to apply the
877 // tougher checks when starting threads that we want to do when resuming them.
878 // However, when start_thread is called as a result of Thread.start, on a Java
879 // thread, the operation is synchronized on the Java Thread object. So there
880 // cannot be a race to start the thread and hence for the thread to exit while
881 // we are working on it. Non-Java threads that start Java threads either have
882 // to do so in a context in which races are impossible, or should do appropriate
883 // locking.
884
885 void os::start_thread(Thread* thread) {
886 // guard suspend/resume
887 MutexLocker ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
888 OSThread* osthread = thread->osthread();
889 osthread->set_state(RUNNABLE);
890 pd_start_thread(thread);
891 }
892
893 void os::abort(bool dump_core) {
894 abort(dump_core && CreateCoredumpOnCrash, NULL, NULL);
895 }
896
897 //---------------------------------------------------------------------------
898 // Helper functions for fatal error handler
899
900 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
901 assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
902
903 start = align_down(start, unitsize);
904
905 int cols = 0;
906 int cols_per_line = 0;
907 switch (unitsize) {
908 case 1: cols_per_line = 16; break;
909 case 2: cols_per_line = 8; break;
910 case 4: cols_per_line = 4; break;
911 case 8: cols_per_line = 2; break;
912 default: return;
913 }
914
915 address p = start;
916 st->print(PTR_FORMAT ": ", p2i(start));
917 while (p < end) {
918 if (is_readable_pointer(p)) {
919 switch (unitsize) {
920 case 1: st->print("%02x", *(u1*)p); break;
921 case 2: st->print("%04x", *(u2*)p); break;
922 case 4: st->print("%08x", *(u4*)p); break;
923 case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
924 }
925 } else {
926 st->print("%*.*s", 2*unitsize, 2*unitsize, "????????????????");
927 }
928 p += unitsize;
929 cols++;
930 if (cols >= cols_per_line && p < end) {
931 cols = 0;
932 st->cr();
933 st->print(PTR_FORMAT ": ", p2i(p));
934 } else {
935 st->print(" ");
936 }
937 }
938 st->cr();
939 }
940
941 void os::print_dhm(outputStream* st, const char* startStr, long sec) {
942 long days = sec/86400;
943 long hours = (sec/3600) - (days * 24);
944 long minutes = (sec/60) - (days * 1440) - (hours * 60);
945 if (startStr == NULL) startStr = "";
946 st->print_cr("%s %ld days %ld:%02ld hours", startStr, days, hours, minutes);
947 }
948
949 void os::print_instructions(outputStream* st, address pc, int unitsize) {
950 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc));
951 print_hex_dump(st, pc - 256, pc + 256, unitsize);
952 }
953
954 void os::print_environment_variables(outputStream* st, const char** env_list) {
955 if (env_list) {
956 st->print_cr("Environment Variables:");
957
958 for (int i = 0; env_list[i] != NULL; i++) {
959 char *envvar = ::getenv(env_list[i]);
960 if (envvar != NULL) {
961 st->print("%s", env_list[i]);
962 st->print("=");
963 st->print_cr("%s", envvar);
964 }
965 }
966 }
967 }
968
969 void os::print_cpu_info(outputStream* st, char* buf, size_t buflen) {
970 // cpu
971 st->print("CPU:");
972 st->print(" total %d", os::processor_count());
973 // It's not safe to query number of active processors after crash
974 // st->print("(active %d)", os::active_processor_count()); but we can
975 // print the initial number of active processors.
976 // We access the raw value here because the assert in the accessor will
977 // fail if the crash occurs before initialization of this value.
978 st->print(" (initial active %d)", _initial_active_processor_count);
979 st->print(" %s", VM_Version::features_string());
980 st->cr();
981 pd_print_cpu_info(st, buf, buflen);
982 }
983
984 // Print a one line string summarizing the cpu, number of cores, memory, and operating system version
985 void os::print_summary_info(outputStream* st, char* buf, size_t buflen) {
986 st->print("Host: ");
987 #ifndef PRODUCT
988 if (get_host_name(buf, buflen)) {
989 st->print("%s, ", buf);
990 }
991 #endif // PRODUCT
992 get_summary_cpu_info(buf, buflen);
993 st->print("%s, ", buf);
994 size_t mem = physical_memory()/G;
995 if (mem == 0) { // for low memory systems
996 mem = physical_memory()/M;
997 st->print("%d cores, " SIZE_FORMAT "M, ", processor_count(), mem);
998 } else {
999 st->print("%d cores, " SIZE_FORMAT "G, ", processor_count(), mem);
1000 }
1001 get_summary_os_info(buf, buflen);
1002 st->print_raw(buf);
1003 st->cr();
1004 }
1005
1006 void os::print_date_and_time(outputStream *st, char* buf, size_t buflen) {
1007 const int secs_per_day = 86400;
1008 const int secs_per_hour = 3600;
1009 const int secs_per_min = 60;
1010
1011 time_t tloc;
1012 (void)time(&tloc);
1013 char* timestring = ctime(&tloc); // ctime adds newline.
1014 // edit out the newline
1015 char* nl = strchr(timestring, '\n');
1016 if (nl != NULL) {
1017 *nl = '\0';
1018 }
1019
1020 struct tm tz;
1021 if (localtime_pd(&tloc, &tz) != NULL) {
1022 ::strftime(buf, buflen, "%Z", &tz);
1023 st->print("Time: %s %s", timestring, buf);
1024 } else {
1025 st->print("Time: %s", timestring);
1026 }
1027
1028 double t = os::elapsedTime();
1029 // NOTE: a crash using printf("%f",...) on Linux was historically noted here.
1030 int eltime = (int)t; // elapsed time in seconds
1031 int eltimeFraction = (int) ((t - eltime) * 1000000);
1032
1033 // print elapsed time in a human-readable format:
1034 int eldays = eltime / secs_per_day;
1035 int day_secs = eldays * secs_per_day;
1036 int elhours = (eltime - day_secs) / secs_per_hour;
1037 int hour_secs = elhours * secs_per_hour;
1038 int elmins = (eltime - day_secs - hour_secs) / secs_per_min;
1039 int minute_secs = elmins * secs_per_min;
1040 int elsecs = (eltime - day_secs - hour_secs - minute_secs);
1041 st->print_cr(" elapsed time: %d.%06d seconds (%dd %dh %dm %ds)", eltime, eltimeFraction, eldays, elhours, elmins, elsecs);
1042 }
1043
1044
1045 // Check if pointer can be read from (4-byte read access).
1046 // Helps to prove validity of a not-NULL pointer.
1047 // Returns true in very early stages of VM life when stub is not yet generated.
1048 #define SAFEFETCH_DEFAULT true
1049 bool os::is_readable_pointer(const void* p) {
1050 if (!CanUseSafeFetch32()) {
1051 return SAFEFETCH_DEFAULT;
1052 }
1053 int* const aligned = (int*) align_down((intptr_t)p, 4);
1054 int cafebabe = 0xcafebabe; // tester value 1
1055 int deadbeef = 0xdeadbeef; // tester value 2
1056 return (SafeFetch32(aligned, cafebabe) != cafebabe) || (SafeFetch32(aligned, deadbeef) != deadbeef);
1057 }
1058
1059 bool os::is_readable_range(const void* from, const void* to) {
1060 if ((uintptr_t)from >= (uintptr_t)to) return false;
1061 for (uintptr_t p = align_down((uintptr_t)from, min_page_size()); p < (uintptr_t)to; p += min_page_size()) {
1062 if (!is_readable_pointer((const void*)p)) {
1063 return false;
1064 }
1065 }
1066 return true;
1067 }
1068
1069
1070 // moved from debug.cpp (used to be find()) but still called from there
1071 // The verbose parameter is only set by the debug code in one case
1072 void os::print_location(outputStream* st, intptr_t x, bool verbose) {
1073 address addr = (address)x;
1074 // Handle NULL first, so later checks don't need to protect against it.
1075 if (addr == NULL) {
1076 st->print_cr("0x0 is NULL");
1077 return;
1078 }
1079
1080 // Check if addr points into a code blob.
1081 CodeBlob* b = CodeCache::find_blob_unsafe(addr);
1082 if (b != NULL) {
1083 b->dump_for_addr(addr, st, verbose);
1084 return;
1085 }
1086
1087 // Check if addr points into Java heap.
1088 if (Universe::heap()->print_location(st, addr)) {
1089 return;
1090 }
1091
1092 bool accessible = is_readable_pointer(addr);
1093
1094 // Check if addr is a JNI handle.
1095 if (align_down((intptr_t)addr, sizeof(intptr_t)) != 0 && accessible) {
1096 if (JNIHandles::is_global_handle((jobject) addr)) {
1097 st->print_cr(INTPTR_FORMAT " is a global jni handle", p2i(addr));
1098 return;
1099 }
1100 if (JNIHandles::is_weak_global_handle((jobject) addr)) {
1101 st->print_cr(INTPTR_FORMAT " is a weak global jni handle", p2i(addr));
1102 return;
1103 }
1104 #ifndef PRODUCT
1105 // we don't keep the block list in product mode
1106 if (JNIHandles::is_local_handle((jobject) addr)) {
1107 st->print_cr(INTPTR_FORMAT " is a local jni handle", p2i(addr));
1108 return;
1109 }
1110 #endif
1111 }
1112
1113 // Check if addr belongs to a Java thread.
1114 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
1115 // If the addr is a java thread print information about that.
1116 if (addr == (address)thread) {
1117 if (verbose) {
1118 thread->print_on(st);
1119 } else {
1120 st->print_cr(INTPTR_FORMAT " is a thread", p2i(addr));
1121 }
1122 return;
1123 }
1124 // If the addr is in the stack region for this thread then report that
1125 // and print thread info
1126 if (thread->is_in_full_stack(addr)) {
1127 st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
1128 INTPTR_FORMAT, p2i(addr), p2i(thread));
1129 if (verbose) thread->print_on(st);
1130 return;
1131 }
1132 }
1133
1134 // Check if in metaspace and print types that have vptrs
1135 if (Metaspace::contains(addr)) {
1136 if (Klass::is_valid((Klass*)addr)) {
1137 st->print_cr(INTPTR_FORMAT " is a pointer to class: ", p2i(addr));
1138 ((Klass*)addr)->print_on(st);
1139 } else if (Method::is_valid_method((const Method*)addr)) {
1140 ((Method*)addr)->print_value_on(st);
1141 st->cr();
1142 } else {
1143 // Use addr->print() from the debugger instead (not here)
1144 st->print_cr(INTPTR_FORMAT " is pointing into metadata", p2i(addr));
1145 }
1146 return;
1147 }
1148
1149 // Compressed klass needs to be decoded first.
1150 #ifdef _LP64
1151 if (UseCompressedClassPointers && ((uintptr_t)addr &~ (uintptr_t)max_juint) == 0) {
1152 narrowKlass narrow_klass = (narrowKlass)(uintptr_t)addr;
1153 Klass* k = CompressedKlassPointers::decode_raw(narrow_klass);
1154
1155 if (Klass::is_valid(k)) {
1156 st->print_cr(UINT32_FORMAT " is a compressed pointer to class: " INTPTR_FORMAT, narrow_klass, p2i((HeapWord*)k));
1157 k->print_on(st);
1158 return;
1159 }
1160 }
1161 #endif
1162
1163 // Try an OS specific find
1164 if (os::find(addr, st)) {
1165 return;
1166 }
1167
1168 if (accessible) {
1169 st->print(INTPTR_FORMAT " points into unknown readable memory:", p2i(addr));
1170 if (is_aligned(addr, sizeof(intptr_t))) {
1171 st->print(" " PTR_FORMAT " |", *(intptr_t*)addr);
1172 }
1173 for (address p = addr; p < align_up(addr + 1, sizeof(intptr_t)); ++p) {
1174 st->print(" %02x", *(u1*)p);
1175 }
1176 st->cr();
1177 return;
1178 }
1179
1180 st->print_cr(INTPTR_FORMAT " is an unknown value", p2i(addr));
1181 }
1182
1183 // Looks like all platforms can use the same function to check if C
1184 // stack is walkable beyond current frame. The check for fp() is not
1185 // necessary on Sparc, but it's harmless.
1186 bool os::is_first_C_frame(frame* fr) {
1187 // Load up sp, fp, sender sp and sender fp, check for reasonable values.
1188 // Check usp first, because if that's bad the other accessors may fault
1189 // on some architectures. Ditto ufp second, etc.
1190 uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
1191 // sp on amd can be 32 bit aligned.
1192 uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
1193
1194 uintptr_t usp = (uintptr_t)fr->sp();
1195 if ((usp & sp_align_mask) != 0) return true;
1196
1197 uintptr_t ufp = (uintptr_t)fr->fp();
1198 if ((ufp & fp_align_mask) != 0) return true;
1199
1200 uintptr_t old_sp = (uintptr_t)fr->sender_sp();
1201 if ((old_sp & sp_align_mask) != 0) return true;
1202 if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
1203
1204 uintptr_t old_fp = (uintptr_t)fr->link();
1205 if ((old_fp & fp_align_mask) != 0) return true;
1206 if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
1207
1208 // stack grows downwards; if old_fp is below current fp or if the stack
1209 // frame is too large, either the stack is corrupted or fp is not saved
1210 // on stack (i.e. on x86, ebp may be used as general register). The stack
1211 // is not walkable beyond current frame.
1212 if (old_fp < ufp) return true;
1213 if (old_fp - ufp > 64 * K) return true;
1214
1215 return false;
1216 }
1217
1218
1219 // Set up the boot classpath.
1220
1221 char* os::format_boot_path(const char* format_string,
1222 const char* home,
1223 int home_len,
1224 char fileSep,
1225 char pathSep) {
1226 assert((fileSep == '/' && pathSep == ':') ||
1227 (fileSep == '\\' && pathSep == ';'), "unexpected separator chars");
1228
1229 // Scan the format string to determine the length of the actual
1230 // boot classpath, and handle platform dependencies as well.
1231 int formatted_path_len = 0;
1232 const char* p;
1233 for (p = format_string; *p != 0; ++p) {
1234 if (*p == '%') formatted_path_len += home_len - 1;
1235 ++formatted_path_len;
1236 }
1237
1238 char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal);
1239
1240 // Create boot classpath from format, substituting separator chars and
1241 // java home directory.
1242 char* q = formatted_path;
1243 for (p = format_string; *p != 0; ++p) {
1244 switch (*p) {
1245 case '%':
1246 strcpy(q, home);
1247 q += home_len;
1248 break;
1249 case '/':
1250 *q++ = fileSep;
1251 break;
1252 case ':':
1253 *q++ = pathSep;
1254 break;
1255 default:
1256 *q++ = *p;
1257 }
1258 }
1259 *q = '\0';
1260
1261 assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
1262 return formatted_path;
1263 }
1264
1265 // This function is a proxy to fopen, it tries to add a non standard flag ('e' or 'N')
1266 // that ensures automatic closing of the file on exec. If it can not find support in
1267 // the underlying c library, it will make an extra system call (fcntl) to ensure automatic
1268 // closing of the file on exec.
1269 FILE* os::fopen(const char* path, const char* mode) {
1270 char modified_mode[20];
1271 assert(strlen(mode) + 1 < sizeof(modified_mode), "mode chars plus one extra must fit in buffer");
1272 sprintf(modified_mode, "%s" LINUX_ONLY("e") BSD_ONLY("e") WINDOWS_ONLY("N"), mode);
1273 FILE* file = ::fopen(path, modified_mode);
1274
1275 #if !(defined LINUX || defined BSD || defined _WINDOWS)
1276 // assume fcntl FD_CLOEXEC support as a backup solution when 'e' or 'N'
1277 // is not supported as mode in fopen
1278 if (file != NULL) {
1279 int fd = fileno(file);
1280 if (fd != -1) {
1281 int fd_flags = fcntl(fd, F_GETFD);
1282 if (fd_flags != -1) {
1283 fcntl(fd, F_SETFD, fd_flags | FD_CLOEXEC);
1284 }
1285 }
1286 }
1287 #endif
1288
1289 return file;
1290 }
1291
1292 bool os::set_boot_path(char fileSep, char pathSep) {
1293 const char* home = Arguments::get_java_home();
1294 int home_len = (int)strlen(home);
1295
1296 struct stat st;
1297
1298 // modular image if "modules" jimage exists
1299 char* jimage = format_boot_path("%/lib/" MODULES_IMAGE_NAME, home, home_len, fileSep, pathSep);
1300 if (jimage == NULL) return false;
1301 bool has_jimage = (os::stat(jimage, &st) == 0);
1302 if (has_jimage) {
1303 Arguments::set_sysclasspath(jimage, true);
1304 FREE_C_HEAP_ARRAY(char, jimage);
1305 return true;
1306 }
1307 FREE_C_HEAP_ARRAY(char, jimage);
1308
1309 // check if developer build with exploded modules
1310 char* base_classes = format_boot_path("%/modules/" JAVA_BASE_NAME, home, home_len, fileSep, pathSep);
1311 if (base_classes == NULL) return false;
1312 if (os::stat(base_classes, &st) == 0) {
1313 Arguments::set_sysclasspath(base_classes, false);
1314 FREE_C_HEAP_ARRAY(char, base_classes);
1315 return true;
1316 }
1317 FREE_C_HEAP_ARRAY(char, base_classes);
1318
1319 return false;
1320 }
1321
1322 // Splits a path, based on its separator, the number of
1323 // elements is returned back in "elements".
1324 // file_name_length is used as a modifier for each path's
1325 // length when compared to JVM_MAXPATHLEN. So if you know
1326 // each returned path will have something appended when
1327 // in use, you can pass the length of that in
1328 // file_name_length, to ensure we detect if any path
1329 // exceeds the maximum path length once prepended onto
1330 // the sub-path/file name.
1331 // It is the callers responsibility to:
1332 // a> check the value of "elements", which may be 0.
1333 // b> ignore any empty path elements
1334 // c> free up the data.
1335 char** os::split_path(const char* path, size_t* elements, size_t file_name_length) {
1336 *elements = (size_t)0;
1337 if (path == NULL || strlen(path) == 0 || file_name_length == (size_t)NULL) {
1338 return NULL;
1339 }
1340 const char psepchar = *os::path_separator();
1341 char* inpath = NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal);
1342 strcpy(inpath, path);
1343 size_t count = 1;
1344 char* p = strchr(inpath, psepchar);
1345 // Get a count of elements to allocate memory
1346 while (p != NULL) {
1347 count++;
1348 p++;
1349 p = strchr(p, psepchar);
1350 }
1351
1352 char** opath = NEW_C_HEAP_ARRAY(char*, count, mtInternal);
1353
1354 // do the actual splitting
1355 p = inpath;
1356 for (size_t i = 0 ; i < count ; i++) {
1357 size_t len = strcspn(p, os::path_separator());
1358 if (len + file_name_length > JVM_MAXPATHLEN) {
1359 // release allocated storage before exiting the vm
1360 free_array_of_char_arrays(opath, i++);
1361 vm_exit_during_initialization("The VM tried to use a path that exceeds the maximum path length for "
1362 "this system. Review path-containing parameters and properties, such as "
1363 "sun.boot.library.path, to identify potential sources for this path.");
1364 }
1365 // allocate the string and add terminator storage
1366 char* s = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
1367 strncpy(s, p, len);
1368 s[len] = '\0';
1369 opath[i] = s;
1370 p += len + 1;
1371 }
1372 FREE_C_HEAP_ARRAY(char, inpath);
1373 *elements = count;
1374 return opath;
1375 }
1376
1377 // Returns true if the current stack pointer is above the stack shadow
1378 // pages, false otherwise.
1379 bool os::stack_shadow_pages_available(Thread *thread, const methodHandle& method, address sp) {
1380 if (!thread->is_Java_thread()) return false;
1381 // Check if we have StackShadowPages above the yellow zone. This parameter
1382 // is dependent on the depth of the maximum VM call stack possible from
1383 // the handler for stack overflow. 'instanceof' in the stack overflow
1384 // handler or a println uses at least 8k stack of VM and native code
1385 // respectively.
1386 const int framesize_in_bytes =
1387 Interpreter::size_top_interpreter_activation(method()) * wordSize;
1388
1389 address limit = ((JavaThread*)thread)->stack_end() +
1390 (JavaThread::stack_guard_zone_size() + JavaThread::stack_shadow_zone_size());
1391
1392 return sp > (limit + framesize_in_bytes);
1393 }
1394
1395 size_t os::page_size_for_region(size_t region_size, size_t min_pages, bool must_be_aligned) {
1396 assert(min_pages > 0, "sanity");
1397 if (UseLargePages) {
1398 const size_t max_page_size = region_size / min_pages;
1399
1400 for (size_t i = 0; _page_sizes[i] != 0; ++i) {
1401 const size_t page_size = _page_sizes[i];
1402 if (page_size <= max_page_size) {
1403 if (!must_be_aligned || is_aligned(region_size, page_size)) {
1404 return page_size;
1405 }
1406 }
1407 }
1408 }
1409
1410 return vm_page_size();
1411 }
1412
1413 size_t os::page_size_for_region_aligned(size_t region_size, size_t min_pages) {
1414 return page_size_for_region(region_size, min_pages, true);
1415 }
1416
1417 size_t os::page_size_for_region_unaligned(size_t region_size, size_t min_pages) {
1418 return page_size_for_region(region_size, min_pages, false);
1419 }
1420
1421 static const char* errno_to_string (int e, bool short_text) {
1422 #define ALL_SHARED_ENUMS(X) \
1423 X(E2BIG, "Argument list too long") \
1424 X(EACCES, "Permission denied") \
1425 X(EADDRINUSE, "Address in use") \
1426 X(EADDRNOTAVAIL, "Address not available") \
1427 X(EAFNOSUPPORT, "Address family not supported") \
1428 X(EAGAIN, "Resource unavailable, try again") \
1429 X(EALREADY, "Connection already in progress") \
1430 X(EBADF, "Bad file descriptor") \
1431 X(EBADMSG, "Bad message") \
1432 X(EBUSY, "Device or resource busy") \
1433 X(ECANCELED, "Operation canceled") \
1434 X(ECHILD, "No child processes") \
1435 X(ECONNABORTED, "Connection aborted") \
1436 X(ECONNREFUSED, "Connection refused") \
1437 X(ECONNRESET, "Connection reset") \
1438 X(EDEADLK, "Resource deadlock would occur") \
1439 X(EDESTADDRREQ, "Destination address required") \
1440 X(EDOM, "Mathematics argument out of domain of function") \
1441 X(EEXIST, "File exists") \
1442 X(EFAULT, "Bad address") \
1443 X(EFBIG, "File too large") \
1444 X(EHOSTUNREACH, "Host is unreachable") \
1445 X(EIDRM, "Identifier removed") \
1446 X(EILSEQ, "Illegal byte sequence") \
1447 X(EINPROGRESS, "Operation in progress") \
1448 X(EINTR, "Interrupted function") \
1449 X(EINVAL, "Invalid argument") \
1450 X(EIO, "I/O error") \
1451 X(EISCONN, "Socket is connected") \
1452 X(EISDIR, "Is a directory") \
1453 X(ELOOP, "Too many levels of symbolic links") \
1454 X(EMFILE, "Too many open files") \
1455 X(EMLINK, "Too many links") \
1456 X(EMSGSIZE, "Message too large") \
1457 X(ENAMETOOLONG, "Filename too long") \
1458 X(ENETDOWN, "Network is down") \
1459 X(ENETRESET, "Connection aborted by network") \
1460 X(ENETUNREACH, "Network unreachable") \
1461 X(ENFILE, "Too many files open in system") \
1462 X(ENOBUFS, "No buffer space available") \
1463 X(ENODATA, "No message is available on the STREAM head read queue") \
1464 X(ENODEV, "No such device") \
1465 X(ENOENT, "No such file or directory") \
1466 X(ENOEXEC, "Executable file format error") \
1467 X(ENOLCK, "No locks available") \
1468 X(ENOLINK, "Reserved") \
1469 X(ENOMEM, "Not enough space") \
1470 X(ENOMSG, "No message of the desired type") \
1471 X(ENOPROTOOPT, "Protocol not available") \
1472 X(ENOSPC, "No space left on device") \
1473 X(ENOSR, "No STREAM resources") \
1474 X(ENOSTR, "Not a STREAM") \
1475 X(ENOSYS, "Function not supported") \
1476 X(ENOTCONN, "The socket is not connected") \
1477 X(ENOTDIR, "Not a directory") \
1478 X(ENOTEMPTY, "Directory not empty") \
1479 X(ENOTSOCK, "Not a socket") \
1480 X(ENOTSUP, "Not supported") \
1481 X(ENOTTY, "Inappropriate I/O control operation") \
1482 X(ENXIO, "No such device or address") \
1483 X(EOPNOTSUPP, "Operation not supported on socket") \
1484 X(EOVERFLOW, "Value too large to be stored in data type") \
1485 X(EPERM, "Operation not permitted") \
1486 X(EPIPE, "Broken pipe") \
1487 X(EPROTO, "Protocol error") \
1488 X(EPROTONOSUPPORT, "Protocol not supported") \
1489 X(EPROTOTYPE, "Protocol wrong type for socket") \
1490 X(ERANGE, "Result too large") \
1491 X(EROFS, "Read-only file system") \
1492 X(ESPIPE, "Invalid seek") \
1493 X(ESRCH, "No such process") \
1494 X(ETIME, "Stream ioctl() timeout") \
1495 X(ETIMEDOUT, "Connection timed out") \
1496 X(ETXTBSY, "Text file busy") \
1497 X(EWOULDBLOCK, "Operation would block") \
1498 X(EXDEV, "Cross-device link")
1499
1500 #define DEFINE_ENTRY(e, text) { e, #e, text },
1501
1502 static const struct {
1503 int v;
1504 const char* short_text;
1505 const char* long_text;
1506 } table [] = {
1507
1508 ALL_SHARED_ENUMS(DEFINE_ENTRY)
1509
1510 // The following enums are not defined on all platforms.
1511 #ifdef ESTALE
1512 DEFINE_ENTRY(ESTALE, "Reserved")
1513 #endif
1514 #ifdef EDQUOT
1515 DEFINE_ENTRY(EDQUOT, "Reserved")
1516 #endif
1517 #ifdef EMULTIHOP
1518 DEFINE_ENTRY(EMULTIHOP, "Reserved")
1519 #endif
1520
1521 // End marker.
1522 { -1, "Unknown errno", "Unknown error" }
1523
1524 };
1525
1526 #undef DEFINE_ENTRY
1527 #undef ALL_FLAGS
1528
1529 int i = 0;
1530 while (table[i].v != -1 && table[i].v != e) {
1531 i ++;
1532 }
1533
1534 return short_text ? table[i].short_text : table[i].long_text;
1535
1536 }
1537
1538 const char* os::strerror(int e) {
1539 return errno_to_string(e, false);
1540 }
1541
1542 const char* os::errno_name(int e) {
1543 return errno_to_string(e, true);
1544 }
1545
1546 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count) {
1547 LogTarget(Info, pagesize) log;
1548 if (log.is_enabled()) {
1549 LogStream out(log);
1550
1551 out.print("%s: ", str);
1552 for (int i = 0; i < count; ++i) {
1553 out.print(" " SIZE_FORMAT, page_sizes[i]);
1554 }
1555 out.cr();
1556 }
1557 }
1558
1559 #define trace_page_size_params(size) byte_size_in_exact_unit(size), exact_unit_for_byte_size(size)
1560
1561 void os::trace_page_sizes(const char* str,
1562 const size_t region_min_size,
1563 const size_t region_max_size,
1564 const size_t page_size,
1565 const char* base,
1566 const size_t size) {
1567
1568 log_info(pagesize)("%s: "
1569 " min=" SIZE_FORMAT "%s"
1570 " max=" SIZE_FORMAT "%s"
1571 " base=" PTR_FORMAT
1572 " page_size=" SIZE_FORMAT "%s"
1573 " size=" SIZE_FORMAT "%s",
1574 str,
1575 trace_page_size_params(region_min_size),
1576 trace_page_size_params(region_max_size),
1577 p2i(base),
1578 trace_page_size_params(page_size),
1579 trace_page_size_params(size));
1580 }
1581
1582 void os::trace_page_sizes_for_requested_size(const char* str,
1583 const size_t requested_size,
1584 const size_t page_size,
1585 const size_t alignment,
1586 const char* base,
1587 const size_t size) {
1588
1589 log_info(pagesize)("%s:"
1590 " req_size=" SIZE_FORMAT "%s"
1591 " base=" PTR_FORMAT
1592 " page_size=" SIZE_FORMAT "%s"
1593 " alignment=" SIZE_FORMAT "%s"
1594 " size=" SIZE_FORMAT "%s",
1595 str,
1596 trace_page_size_params(requested_size),
1597 p2i(base),
1598 trace_page_size_params(page_size),
1599 trace_page_size_params(alignment),
1600 trace_page_size_params(size));
1601 }
1602
1603
1604 // This is the working definition of a server class machine:
1605 // >= 2 physical CPU's and >=2GB of memory, with some fuzz
1606 // because the graphics memory (?) sometimes masks physical memory.
1607 // If you want to change the definition of a server class machine
1608 // on some OS or platform, e.g., >=4GB on Windows platforms,
1609 // then you'll have to parameterize this method based on that state,
1610 // as was done for logical processors here, or replicate and
1611 // specialize this method for each platform. (Or fix os to have
1612 // some inheritance structure and use subclassing. Sigh.)
1613 // If you want some platform to always or never behave as a server
1614 // class machine, change the setting of AlwaysActAsServerClassMachine
1615 // and NeverActAsServerClassMachine in globals*.hpp.
1616 bool os::is_server_class_machine() {
1617 // First check for the early returns
1618 if (NeverActAsServerClassMachine) {
1619 return false;
1620 }
1621 if (AlwaysActAsServerClassMachine) {
1622 return true;
1623 }
1624 // Then actually look at the machine
1625 bool result = false;
1626 const unsigned int server_processors = 2;
1627 const julong server_memory = 2UL * G;
1628 // We seem not to get our full complement of memory.
1629 // We allow some part (1/8?) of the memory to be "missing",
1630 // based on the sizes of DIMMs, and maybe graphics cards.
1631 const julong missing_memory = 256UL * M;
1632
1633 /* Is this a server class machine? */
1634 if ((os::active_processor_count() >= (int)server_processors) &&
1635 (os::physical_memory() >= (server_memory - missing_memory))) {
1636 const unsigned int logical_processors =
1637 VM_Version::logical_processors_per_package();
1638 if (logical_processors > 1) {
1639 const unsigned int physical_packages =
1640 os::active_processor_count() / logical_processors;
1641 if (physical_packages >= server_processors) {
1642 result = true;
1643 }
1644 } else {
1645 result = true;
1646 }
1647 }
1648 return result;
1649 }
1650
1651 void os::initialize_initial_active_processor_count() {
1652 assert(_initial_active_processor_count == 0, "Initial active processor count already set.");
1653 _initial_active_processor_count = active_processor_count();
1654 log_debug(os)("Initial active processor count set to %d" , _initial_active_processor_count);
1655 }
1656
1657 void os::SuspendedThreadTask::run() {
1658 internal_do_task();
1659 _done = true;
1660 }
1661
1662 bool os::create_stack_guard_pages(char* addr, size_t bytes) {
1663 return os::pd_create_stack_guard_pages(addr, bytes);
1664 }
1665
1666 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint, int file_desc) {
1667 char* result = NULL;
1668
1669 if (file_desc != -1) {
1670 // Could have called pd_reserve_memory() followed by replace_existing_mapping_with_file_mapping(),
1671 // but AIX may use SHM in which case its more trouble to detach the segment and remap memory to the file.
1672 result = os::map_memory_to_file(addr, bytes, file_desc);
1673 if (result != NULL) {
1674 MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1675 }
1676 } else {
1677 result = pd_reserve_memory(bytes, addr, alignment_hint);
1678 if (result != NULL) {
1679 MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1680 }
1681 }
1682
1683 return result;
1684 }
1685
1686 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint,
1687 MEMFLAGS flags) {
1688 char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1689 if (result != NULL) {
1690 MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1691 MemTracker::record_virtual_memory_type((address)result, flags);
1692 }
1693
1694 return result;
1695 }
1696
1697 char* os::attempt_reserve_memory_at(size_t bytes, char* addr, int file_desc) {
1698 char* result = NULL;
1699 if (file_desc != -1) {
1700 result = pd_attempt_reserve_memory_at(bytes, addr, file_desc);
1701 if (result != NULL) {
1702 MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1703 }
1704 } else {
1705 result = pd_attempt_reserve_memory_at(bytes, addr);
1706 if (result != NULL) {
1707 MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1708 }
1709 }
1710 return result;
1711 }
1712
1713 bool os::commit_memory(char* addr, size_t bytes, bool executable) {
1714 bool res = pd_commit_memory(addr, bytes, executable);
1715 if (res) {
1716 MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1717 }
1718 return res;
1719 }
1720
1721 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
1722 bool executable) {
1723 bool res = os::pd_commit_memory(addr, size, alignment_hint, executable);
1724 if (res) {
1725 MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1726 }
1727 return res;
1728 }
1729
1730 void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable,
1731 const char* mesg) {
1732 pd_commit_memory_or_exit(addr, bytes, executable, mesg);
1733 MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1734 }
1735
1736 void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint,
1737 bool executable, const char* mesg) {
1738 os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg);
1739 MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1740 }
1741
1742 bool os::uncommit_memory(char* addr, size_t bytes) {
1743 bool res;
1744 if (MemTracker::tracking_level() > NMT_minimal) {
1745 Tracker tkr(Tracker::uncommit);
1746 res = pd_uncommit_memory(addr, bytes);
1747 if (res) {
1748 tkr.record((address)addr, bytes);
1749 }
1750 } else {
1751 res = pd_uncommit_memory(addr, bytes);
1752 }
1753 return res;
1754 }
1755
1756 bool os::release_memory(char* addr, size_t bytes) {
1757 bool res;
1758 if (MemTracker::tracking_level() > NMT_minimal) {
1759 // Note: Tracker contains a ThreadCritical.
1760 Tracker tkr(Tracker::release);
1761 res = pd_release_memory(addr, bytes);
1762 if (res) {
1763 tkr.record((address)addr, bytes);
1764 }
1765 } else {
1766 res = pd_release_memory(addr, bytes);
1767 }
1768 return res;
1769 }
1770
1771 void os::pretouch_memory(void* start, void* end, size_t page_size) {
1772 for (volatile char *p = (char*)start; p < (char*)end; p += page_size) {
1773 *p = 0;
1774 }
1775 }
1776
1777 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
1778 char *addr, size_t bytes, bool read_only,
1779 bool allow_exec, MEMFLAGS flags) {
1780 char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec);
1781 if (result != NULL) {
1782 MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC, flags);
1783 }
1784 return result;
1785 }
1786
1787 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
1788 char *addr, size_t bytes, bool read_only,
1789 bool allow_exec) {
1790 return pd_remap_memory(fd, file_name, file_offset, addr, bytes,
1791 read_only, allow_exec);
1792 }
1793
1794 bool os::unmap_memory(char *addr, size_t bytes) {
1795 bool result;
1796 if (MemTracker::tracking_level() > NMT_minimal) {
1797 Tracker tkr(Tracker::release);
1798 result = pd_unmap_memory(addr, bytes);
1799 if (result) {
1800 tkr.record((address)addr, bytes);
1801 }
1802 } else {
1803 result = pd_unmap_memory(addr, bytes);
1804 }
1805 return result;
1806 }
1807
1808 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
1809 pd_free_memory(addr, bytes, alignment_hint);
1810 }
1811
1812 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
1813 pd_realign_memory(addr, bytes, alignment_hint);
1814 }
1815
1816 char* os::reserve_memory_special(size_t size, size_t alignment,
1817 char* addr, bool executable) {
1818
1819 assert(is_aligned(addr, alignment), "Unaligned request address");
1820
1821 char* result = pd_reserve_memory_special(size, alignment, addr, executable);
1822 if (result != NULL) {
1823 // The memory is committed
1824 MemTracker::record_virtual_memory_reserve_and_commit((address)result, size, CALLER_PC);
1825 }
1826
1827 return result;
1828 }
1829
1830 bool os::release_memory_special(char* addr, size_t bytes) {
1831 bool res;
1832 if (MemTracker::tracking_level() > NMT_minimal) {
1833 // Note: Tracker contains a ThreadCritical.
1834 Tracker tkr(Tracker::release);
1835 res = pd_release_memory_special(addr, bytes);
1836 if (res) {
1837 tkr.record((address)addr, bytes);
1838 }
1839 } else {
1840 res = pd_release_memory_special(addr, bytes);
1841 }
1842 return res;
1843 }
1844
1845 #ifndef _WINDOWS
1846 /* try to switch state from state "from" to state "to"
1847 * returns the state set after the method is complete
1848 */
1849 os::SuspendResume::State os::SuspendResume::switch_state(os::SuspendResume::State from,
1850 os::SuspendResume::State to)
1851 {
1852 os::SuspendResume::State result = Atomic::cmpxchg(&_state, from, to);
1853 if (result == from) {
1854 // success
1855 return to;
1856 }
1857 return result;
1858 }
1859 #endif
1860
1861 // Convenience wrapper around naked_short_sleep to allow for longer sleep
1862 // times. Only for use by non-JavaThreads.
1863 void os::naked_sleep(jlong millis) {
1864 assert(!Thread::current()->is_Java_thread(), "not for use by JavaThreads");
1865 const jlong limit = 999;
1866 while (millis > limit) {
1867 naked_short_sleep(limit);
1868 millis -= limit;
1869 }
1870 naked_short_sleep(millis);
1871 }