1 /*
2 * Copyright (c) 1997, 2009, 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 "incls/_precompiled.incl"
26 # include "incls/_os.cpp.incl"
27
28 # include <signal.h>
29
30 OSThread* os::_starting_thread = NULL;
31 address os::_polling_page = NULL;
32 volatile int32_t* os::_mem_serialize_page = NULL;
33 uintptr_t os::_serialize_page_mask = 0;
34 long os::_rand_seed = 1;
35 int os::_processor_count = 0;
36 size_t os::_page_sizes[os::page_sizes_max];
37
38 #ifndef PRODUCT
39 int os::num_mallocs = 0; // # of calls to malloc/realloc
40 size_t os::alloc_bytes = 0; // # of bytes allocated
41 int os::num_frees = 0; // # of calls to free
42 #endif
43
44 // Fill in buffer with current local time as an ISO-8601 string.
45 // E.g., yyyy-mm-ddThh:mm:ss-zzzz.
46 // Returns buffer, or NULL if it failed.
47 // This would mostly be a call to
48 // strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
49 // except that on Windows the %z behaves badly, so we do it ourselves.
50 // Also, people wanted milliseconds on there,
51 // and strftime doesn't do milliseconds.
52 char* os::iso8601_time(char* buffer, size_t buffer_length) {
53 // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
54 // 1 2
55 // 12345678901234567890123456789
56 static const char* iso8601_format =
57 "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d";
58 static const size_t needed_buffer = 29;
59
60 // Sanity check the arguments
61 if (buffer == NULL) {
62 assert(false, "NULL buffer");
63 return NULL;
64 }
65 if (buffer_length < needed_buffer) {
66 assert(false, "buffer_length too small");
67 return NULL;
68 }
69 // Get the current time
70 jlong milliseconds_since_19700101 = javaTimeMillis();
71 const int milliseconds_per_microsecond = 1000;
72 const time_t seconds_since_19700101 =
73 milliseconds_since_19700101 / milliseconds_per_microsecond;
74 const int milliseconds_after_second =
75 milliseconds_since_19700101 % milliseconds_per_microsecond;
76 // Convert the time value to a tm and timezone variable
77 struct tm time_struct;
78 if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
79 assert(false, "Failed localtime_pd");
80 return NULL;
81 }
82 const time_t zone = timezone;
83
84 // If daylight savings time is in effect,
85 // we are 1 hour East of our time zone
86 const time_t seconds_per_minute = 60;
87 const time_t minutes_per_hour = 60;
88 const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
89 time_t UTC_to_local = zone;
90 if (time_struct.tm_isdst > 0) {
91 UTC_to_local = UTC_to_local - seconds_per_hour;
92 }
93 // Compute the time zone offset.
94 // localtime_pd() sets timezone to the difference (in seconds)
95 // between UTC and and local time.
96 // ISO 8601 says we need the difference between local time and UTC,
97 // we change the sign of the localtime_pd() result.
98 const time_t local_to_UTC = -(UTC_to_local);
99 // Then we have to figure out if if we are ahead (+) or behind (-) UTC.
100 char sign_local_to_UTC = '+';
101 time_t abs_local_to_UTC = local_to_UTC;
102 if (local_to_UTC < 0) {
103 sign_local_to_UTC = '-';
104 abs_local_to_UTC = -(abs_local_to_UTC);
105 }
106 // Convert time zone offset seconds to hours and minutes.
107 const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
108 const time_t zone_min =
109 ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
110
111 // Print an ISO 8601 date and time stamp into the buffer
112 const int year = 1900 + time_struct.tm_year;
113 const int month = 1 + time_struct.tm_mon;
114 const int printed = jio_snprintf(buffer, buffer_length, iso8601_format,
115 year,
116 month,
117 time_struct.tm_mday,
118 time_struct.tm_hour,
119 time_struct.tm_min,
120 time_struct.tm_sec,
121 milliseconds_after_second,
122 sign_local_to_UTC,
123 zone_hours,
124 zone_min);
125 if (printed == 0) {
126 assert(false, "Failed jio_printf");
127 return NULL;
128 }
129 return buffer;
130 }
131
132 OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
133 #ifdef ASSERT
134 if (!(!thread->is_Java_thread() ||
135 Thread::current() == thread ||
136 Threads_lock->owned_by_self()
137 || thread->is_Compiler_thread()
138 )) {
139 assert(false, "possibility of dangling Thread pointer");
140 }
141 #endif
142
143 if (p >= MinPriority && p <= MaxPriority) {
144 int priority = java_to_os_priority[p];
145 return set_native_priority(thread, priority);
146 } else {
147 assert(false, "Should not happen");
148 return OS_ERR;
149 }
150 }
151
152
153 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
154 int p;
155 int os_prio;
156 OSReturn ret = get_native_priority(thread, &os_prio);
157 if (ret != OS_OK) return ret;
158
159 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
160 priority = (ThreadPriority)p;
161 return OS_OK;
162 }
163
164
165 // --------------------- sun.misc.Signal (optional) ---------------------
166
167
168 // SIGBREAK is sent by the keyboard to query the VM state
169 #ifndef SIGBREAK
170 #define SIGBREAK SIGQUIT
171 #endif
172
173 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
174
175
176 static void signal_thread_entry(JavaThread* thread, TRAPS) {
177 os::set_priority(thread, NearMaxPriority);
178 while (true) {
179 int sig;
180 {
181 // FIXME : Currently we have not decieded what should be the status
182 // for this java thread blocked here. Once we decide about
183 // that we should fix this.
184 sig = os::signal_wait();
185 }
186 if (sig == os::sigexitnum_pd()) {
187 // Terminate the signal thread
188 return;
189 }
190
191 switch (sig) {
192 case SIGBREAK: {
193 // Check if the signal is a trigger to start the Attach Listener - in that
194 // case don't print stack traces.
195 if (!DisableAttachMechanism && AttachListener::is_init_trigger()) {
196 continue;
197 }
198 // Print stack traces
199 // Any SIGBREAK operations added here should make sure to flush
200 // the output stream (e.g. tty->flush()) after output. See 4803766.
201 // Each module also prints an extra carriage return after its output.
202 VM_PrintThreads op;
203 VMThread::execute(&op);
204 VM_PrintJNI jni_op;
205 VMThread::execute(&jni_op);
206 VM_FindDeadlocks op1(tty);
207 VMThread::execute(&op1);
208 Universe::print_heap_at_SIGBREAK();
209 if (PrintClassHistogram) {
210 VM_GC_HeapInspection op1(gclog_or_tty, true /* force full GC before heap inspection */,
211 true /* need_prologue */);
212 VMThread::execute(&op1);
213 }
214 if (JvmtiExport::should_post_data_dump()) {
215 JvmtiExport::post_data_dump();
216 }
217 break;
218 }
219 default: {
220 // Dispatch the signal to java
221 HandleMark hm(THREAD);
222 klassOop k = SystemDictionary::resolve_or_null(vmSymbolHandles::sun_misc_Signal(), THREAD);
223 KlassHandle klass (THREAD, k);
224 if (klass.not_null()) {
225 JavaValue result(T_VOID);
226 JavaCallArguments args;
227 args.push_int(sig);
228 JavaCalls::call_static(
229 &result,
230 klass,
231 vmSymbolHandles::dispatch_name(),
232 vmSymbolHandles::int_void_signature(),
233 &args,
234 THREAD
235 );
236 }
237 if (HAS_PENDING_EXCEPTION) {
238 // tty is initialized early so we don't expect it to be null, but
239 // if it is we can't risk doing an initialization that might
240 // trigger additional out-of-memory conditions
241 if (tty != NULL) {
242 char klass_name[256];
243 char tmp_sig_name[16];
244 const char* sig_name = "UNKNOWN";
245 instanceKlass::cast(PENDING_EXCEPTION->klass())->
246 name()->as_klass_external_name(klass_name, 256);
247 if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
248 sig_name = tmp_sig_name;
249 warning("Exception %s occurred dispatching signal %s to handler"
250 "- the VM may need to be forcibly terminated",
251 klass_name, sig_name );
252 }
253 CLEAR_PENDING_EXCEPTION;
254 }
255 }
256 }
257 }
258 }
259
260
261 void os::signal_init() {
262 if (!ReduceSignalUsage) {
263 // Setup JavaThread for processing signals
264 EXCEPTION_MARK;
265 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
266 instanceKlassHandle klass (THREAD, k);
267 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
268
269 const char thread_name[] = "Signal Dispatcher";
270 Handle string = java_lang_String::create_from_str(thread_name, CHECK);
271
272 // Initialize thread_oop to put it into the system threadGroup
273 Handle thread_group (THREAD, Universe::system_thread_group());
274 JavaValue result(T_VOID);
275 JavaCalls::call_special(&result, thread_oop,
276 klass,
277 vmSymbolHandles::object_initializer_name(),
278 vmSymbolHandles::threadgroup_string_void_signature(),
279 thread_group,
280 string,
281 CHECK);
282
283 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
284 JavaCalls::call_special(&result,
285 thread_group,
286 group,
287 vmSymbolHandles::add_method_name(),
288 vmSymbolHandles::thread_void_signature(),
289 thread_oop, // ARG 1
290 CHECK);
291
292 os::signal_init_pd();
293
294 { MutexLocker mu(Threads_lock);
295 JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
296
297 // At this point it may be possible that no osthread was created for the
298 // JavaThread due to lack of memory. We would have to throw an exception
299 // in that case. However, since this must work and we do not allow
300 // exceptions anyway, check and abort if this fails.
301 if (signal_thread == NULL || signal_thread->osthread() == NULL) {
302 vm_exit_during_initialization("java.lang.OutOfMemoryError",
303 "unable to create new native thread");
304 }
305
306 java_lang_Thread::set_thread(thread_oop(), signal_thread);
307 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
308 java_lang_Thread::set_daemon(thread_oop());
309
310 signal_thread->set_threadObj(thread_oop());
311 Threads::add(signal_thread);
312 Thread::start(signal_thread);
313 }
314 // Handle ^BREAK
315 os::signal(SIGBREAK, os::user_handler());
316 }
317 }
318
319
320 void os::terminate_signal_thread() {
321 if (!ReduceSignalUsage)
322 signal_notify(sigexitnum_pd());
323 }
324
325
326 // --------------------- loading libraries ---------------------
327
328 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
329 extern struct JavaVM_ main_vm;
330
331 static void* _native_java_library = NULL;
332
333 void* os::native_java_library() {
334 if (_native_java_library == NULL) {
335 char buffer[JVM_MAXPATHLEN];
336 char ebuf[1024];
337
338 // Try to load verify dll first. In 1.3 java dll depends on it and is not
339 // always able to find it when the loading executable is outside the JDK.
340 // In order to keep working with 1.2 we ignore any loading errors.
341 dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "verify");
342 dll_load(buffer, ebuf, sizeof(ebuf));
343
344 // Load java dll
345 dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "java");
346 _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
347 if (_native_java_library == NULL) {
348 vm_exit_during_initialization("Unable to load native library", ebuf);
349 }
350 }
351 static jboolean onLoaded = JNI_FALSE;
352 if (onLoaded) {
353 // We may have to wait to fire OnLoad until TLS is initialized.
354 if (ThreadLocalStorage::is_initialized()) {
355 // The JNI_OnLoad handling is normally done by method load in
356 // java.lang.ClassLoader$NativeLibrary, but the VM loads the base library
357 // explicitly so we have to check for JNI_OnLoad as well
358 const char *onLoadSymbols[] = JNI_ONLOAD_SYMBOLS;
359 JNI_OnLoad_t JNI_OnLoad = CAST_TO_FN_PTR(
360 JNI_OnLoad_t, dll_lookup(_native_java_library, onLoadSymbols[0]));
361 if (JNI_OnLoad != NULL) {
362 JavaThread* thread = JavaThread::current();
363 ThreadToNativeFromVM ttn(thread);
364 HandleMark hm(thread);
365 jint ver = (*JNI_OnLoad)(&main_vm, NULL);
366 onLoaded = JNI_TRUE;
367 if (!Threads::is_supported_jni_version_including_1_1(ver)) {
368 vm_exit_during_initialization("Unsupported JNI version");
369 }
370 }
371 }
372 }
373 return _native_java_library;
374 }
375
376 // --------------------- heap allocation utilities ---------------------
377
378 char *os::strdup(const char *str) {
379 size_t size = strlen(str);
380 char *dup_str = (char *)malloc(size + 1);
381 if (dup_str == NULL) return NULL;
382 strcpy(dup_str, str);
383 return dup_str;
384 }
385
386
387
388 #ifdef ASSERT
389 #define space_before (MallocCushion + sizeof(double))
390 #define space_after MallocCushion
391 #define size_addr_from_base(p) (size_t*)(p + space_before - sizeof(size_t))
392 #define size_addr_from_obj(p) ((size_t*)p - 1)
393 // MallocCushion: size of extra cushion allocated around objects with +UseMallocOnly
394 // NB: cannot be debug variable, because these aren't set from the command line until
395 // *after* the first few allocs already happened
396 #define MallocCushion 16
397 #else
398 #define space_before 0
399 #define space_after 0
400 #define size_addr_from_base(p) should not use w/o ASSERT
401 #define size_addr_from_obj(p) should not use w/o ASSERT
402 #define MallocCushion 0
403 #endif
404 #define paranoid 0 /* only set to 1 if you suspect checking code has bug */
405
406 #ifdef ASSERT
407 inline size_t get_size(void* obj) {
408 size_t size = *size_addr_from_obj(obj);
409 if (size < 0) {
410 fatal(err_msg("free: size field of object #" PTR_FORMAT " was overwritten ("
411 SIZE_FORMAT ")", obj, size));
412 }
413 return size;
414 }
415
416 u_char* find_cushion_backwards(u_char* start) {
417 u_char* p = start;
418 while (p[ 0] != badResourceValue || p[-1] != badResourceValue ||
419 p[-2] != badResourceValue || p[-3] != badResourceValue) p--;
420 // ok, we have four consecutive marker bytes; find start
421 u_char* q = p - 4;
422 while (*q == badResourceValue) q--;
423 return q + 1;
424 }
425
426 u_char* find_cushion_forwards(u_char* start) {
427 u_char* p = start;
428 while (p[0] != badResourceValue || p[1] != badResourceValue ||
429 p[2] != badResourceValue || p[3] != badResourceValue) p++;
430 // ok, we have four consecutive marker bytes; find end of cushion
431 u_char* q = p + 4;
432 while (*q == badResourceValue) q++;
433 return q - MallocCushion;
434 }
435
436 void print_neighbor_blocks(void* ptr) {
437 // find block allocated before ptr (not entirely crash-proof)
438 if (MallocCushion < 4) {
439 tty->print_cr("### cannot find previous block (MallocCushion < 4)");
440 return;
441 }
442 u_char* start_of_this_block = (u_char*)ptr - space_before;
443 u_char* end_of_prev_block_data = start_of_this_block - space_after -1;
444 // look for cushion in front of prev. block
445 u_char* start_of_prev_block = find_cushion_backwards(end_of_prev_block_data);
446 ptrdiff_t size = *size_addr_from_base(start_of_prev_block);
447 u_char* obj = start_of_prev_block + space_before;
448 if (size <= 0 ) {
449 // start is bad; mayhave been confused by OS data inbetween objects
450 // search one more backwards
451 start_of_prev_block = find_cushion_backwards(start_of_prev_block);
452 size = *size_addr_from_base(start_of_prev_block);
453 obj = start_of_prev_block + space_before;
454 }
455
456 if (start_of_prev_block + space_before + size + space_after == start_of_this_block) {
457 tty->print_cr("### previous object: %p (%ld bytes)", obj, size);
458 } else {
459 tty->print_cr("### previous object (not sure if correct): %p (%ld bytes)", obj, size);
460 }
461
462 // now find successor block
463 u_char* start_of_next_block = (u_char*)ptr + *size_addr_from_obj(ptr) + space_after;
464 start_of_next_block = find_cushion_forwards(start_of_next_block);
465 u_char* next_obj = start_of_next_block + space_before;
466 ptrdiff_t next_size = *size_addr_from_base(start_of_next_block);
467 if (start_of_next_block[0] == badResourceValue &&
468 start_of_next_block[1] == badResourceValue &&
469 start_of_next_block[2] == badResourceValue &&
470 start_of_next_block[3] == badResourceValue) {
471 tty->print_cr("### next object: %p (%ld bytes)", next_obj, next_size);
472 } else {
473 tty->print_cr("### next object (not sure if correct): %p (%ld bytes)", next_obj, next_size);
474 }
475 }
476
477
478 void report_heap_error(void* memblock, void* bad, const char* where) {
479 tty->print_cr("## nof_mallocs = %d, nof_frees = %d", os::num_mallocs, os::num_frees);
480 tty->print_cr("## memory stomp: byte at %p %s object %p", bad, where, memblock);
481 print_neighbor_blocks(memblock);
482 fatal("memory stomping error");
483 }
484
485 void verify_block(void* memblock) {
486 size_t size = get_size(memblock);
487 if (MallocCushion) {
488 u_char* ptr = (u_char*)memblock - space_before;
489 for (int i = 0; i < MallocCushion; i++) {
490 if (ptr[i] != badResourceValue) {
491 report_heap_error(memblock, ptr+i, "in front of");
492 }
493 }
494 u_char* end = (u_char*)memblock + size + space_after;
495 for (int j = -MallocCushion; j < 0; j++) {
496 if (end[j] != badResourceValue) {
497 report_heap_error(memblock, end+j, "after");
498 }
499 }
500 }
501 }
502 #endif
503
504 void* os::malloc(size_t size) {
505 NOT_PRODUCT(num_mallocs++);
506 NOT_PRODUCT(alloc_bytes += size);
507
508 if (size == 0) {
509 // return a valid pointer if size is zero
510 // if NULL is returned the calling functions assume out of memory.
511 size = 1;
512 }
513
514 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
515 u_char* ptr = (u_char*)::malloc(size + space_before + space_after);
516 #ifdef ASSERT
517 if (ptr == NULL) return NULL;
518 if (MallocCushion) {
519 for (u_char* p = ptr; p < ptr + MallocCushion; p++) *p = (u_char)badResourceValue;
520 u_char* end = ptr + space_before + size;
521 for (u_char* pq = ptr+MallocCushion; pq < end; pq++) *pq = (u_char)uninitBlockPad;
522 for (u_char* q = end; q < end + MallocCushion; q++) *q = (u_char)badResourceValue;
523 }
524 // put size just before data
525 *size_addr_from_base(ptr) = size;
526 #endif
527 u_char* memblock = ptr + space_before;
528 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
529 tty->print_cr("os::malloc caught, %lu bytes --> %p", size, memblock);
530 breakpoint();
531 }
532 debug_only(if (paranoid) verify_block(memblock));
533 if (PrintMalloc && tty != NULL) tty->print_cr("os::malloc %lu bytes --> %p", size, memblock);
534 return memblock;
535 }
536
537
538 void* os::realloc(void *memblock, size_t size) {
539 NOT_PRODUCT(num_mallocs++);
540 NOT_PRODUCT(alloc_bytes += size);
541 #ifndef ASSERT
542 return ::realloc(memblock, size);
543 #else
544 if (memblock == NULL) {
545 return os::malloc(size);
546 }
547 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
548 tty->print_cr("os::realloc caught %p", memblock);
549 breakpoint();
550 }
551 verify_block(memblock);
552 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
553 if (size == 0) return NULL;
554 // always move the block
555 void* ptr = malloc(size);
556 if (PrintMalloc) tty->print_cr("os::remalloc %lu bytes, %p --> %p", size, memblock, ptr);
557 // Copy to new memory if malloc didn't fail
558 if ( ptr != NULL ) {
559 memcpy(ptr, memblock, MIN2(size, get_size(memblock)));
560 if (paranoid) verify_block(ptr);
561 if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
562 tty->print_cr("os::realloc caught, %lu bytes --> %p", size, ptr);
563 breakpoint();
564 }
565 free(memblock);
566 }
567 return ptr;
568 #endif
569 }
570
571
572 void os::free(void *memblock) {
573 NOT_PRODUCT(num_frees++);
574 #ifdef ASSERT
575 if (memblock == NULL) return;
576 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
577 if (tty != NULL) tty->print_cr("os::free caught %p", memblock);
578 breakpoint();
579 }
580 verify_block(memblock);
581 if (PrintMalloc && tty != NULL)
582 // tty->print_cr("os::free %p", memblock);
583 fprintf(stderr, "os::free %p\n", memblock);
584 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
585 // Added by detlefs.
586 if (MallocCushion) {
587 u_char* ptr = (u_char*)memblock - space_before;
588 for (u_char* p = ptr; p < ptr + MallocCushion; p++) {
589 guarantee(*p == badResourceValue,
590 "Thing freed should be malloc result.");
591 *p = (u_char)freeBlockPad;
592 }
593 size_t size = get_size(memblock);
594 u_char* end = ptr + space_before + size;
595 for (u_char* q = end; q < end + MallocCushion; q++) {
596 guarantee(*q == badResourceValue,
597 "Thing freed should be malloc result.");
598 *q = (u_char)freeBlockPad;
599 }
600 }
601 #endif
602 ::free((char*)memblock - space_before);
603 }
604
605 void os::init_random(long initval) {
606 _rand_seed = initval;
607 }
608
609
610 long os::random() {
611 /* standard, well-known linear congruential random generator with
612 * next_rand = (16807*seed) mod (2**31-1)
613 * see
614 * (1) "Random Number Generators: Good Ones Are Hard to Find",
615 * S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
616 * (2) "Two Fast Implementations of the 'Minimal Standard' Random
617 * Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
618 */
619 const long a = 16807;
620 const unsigned long m = 2147483647;
621 const long q = m / a; assert(q == 127773, "weird math");
622 const long r = m % a; assert(r == 2836, "weird math");
623
624 // compute az=2^31p+q
625 unsigned long lo = a * (long)(_rand_seed & 0xFFFF);
626 unsigned long hi = a * (long)((unsigned long)_rand_seed >> 16);
627 lo += (hi & 0x7FFF) << 16;
628
629 // if q overflowed, ignore the overflow and increment q
630 if (lo > m) {
631 lo &= m;
632 ++lo;
633 }
634 lo += hi >> 15;
635
636 // if (p+q) overflowed, ignore the overflow and increment (p+q)
637 if (lo > m) {
638 lo &= m;
639 ++lo;
640 }
641 return (_rand_seed = lo);
642 }
643
644 // The INITIALIZED state is distinguished from the SUSPENDED state because the
645 // conditions in which a thread is first started are different from those in which
646 // a suspension is resumed. These differences make it hard for us to apply the
647 // tougher checks when starting threads that we want to do when resuming them.
648 // However, when start_thread is called as a result of Thread.start, on a Java
649 // thread, the operation is synchronized on the Java Thread object. So there
650 // cannot be a race to start the thread and hence for the thread to exit while
651 // we are working on it. Non-Java threads that start Java threads either have
652 // to do so in a context in which races are impossible, or should do appropriate
653 // locking.
654
655 void os::start_thread(Thread* thread) {
656 // guard suspend/resume
657 MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
658 OSThread* osthread = thread->osthread();
659 osthread->set_state(RUNNABLE);
660 pd_start_thread(thread);
661 }
662
663 //---------------------------------------------------------------------------
664 // Helper functions for fatal error handler
665
666 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
667 assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
668
669 int cols = 0;
670 int cols_per_line = 0;
671 switch (unitsize) {
672 case 1: cols_per_line = 16; break;
673 case 2: cols_per_line = 8; break;
674 case 4: cols_per_line = 4; break;
675 case 8: cols_per_line = 2; break;
676 default: return;
677 }
678
679 address p = start;
680 st->print(PTR_FORMAT ": ", start);
681 while (p < end) {
682 switch (unitsize) {
683 case 1: st->print("%02x", *(u1*)p); break;
684 case 2: st->print("%04x", *(u2*)p); break;
685 case 4: st->print("%08x", *(u4*)p); break;
686 case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
687 }
688 p += unitsize;
689 cols++;
690 if (cols >= cols_per_line && p < end) {
691 cols = 0;
692 st->cr();
693 st->print(PTR_FORMAT ": ", p);
694 } else {
695 st->print(" ");
696 }
697 }
698 st->cr();
699 }
700
701 void os::print_environment_variables(outputStream* st, const char** env_list,
702 char* buffer, int len) {
703 if (env_list) {
704 st->print_cr("Environment Variables:");
705
706 for (int i = 0; env_list[i] != NULL; i++) {
707 if (getenv(env_list[i], buffer, len)) {
708 st->print(env_list[i]);
709 st->print("=");
710 st->print_cr(buffer);
711 }
712 }
713 }
714 }
715
716 void os::print_cpu_info(outputStream* st) {
717 // cpu
718 st->print("CPU:");
719 st->print("total %d", os::processor_count());
720 // It's not safe to query number of active processors after crash
721 // st->print("(active %d)", os::active_processor_count());
722 st->print(" %s", VM_Version::cpu_features());
723 st->cr();
724 }
725
726 void os::print_date_and_time(outputStream *st) {
727 time_t tloc;
728 (void)time(&tloc);
729 st->print("time: %s", ctime(&tloc)); // ctime adds newline.
730
731 double t = os::elapsedTime();
732 // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
733 // Linux. Must be a bug in glibc ? Workaround is to round "t" to int
734 // before printf. We lost some precision, but who cares?
735 st->print_cr("elapsed time: %d seconds", (int)t);
736 }
737
738 // moved from debug.cpp (used to be find()) but still called from there
739 // The print_pc parameter is only set by the debug code in one case
740 void os::print_location(outputStream* st, intptr_t x, bool print_pc) {
741 address addr = (address)x;
742 CodeBlob* b = CodeCache::find_blob_unsafe(addr);
743 if (b != NULL) {
744 if (b->is_buffer_blob()) {
745 // the interpreter is generated into a buffer blob
746 InterpreterCodelet* i = Interpreter::codelet_containing(addr);
747 if (i != NULL) {
748 i->print_on(st);
749 return;
750 }
751 if (Interpreter::contains(addr)) {
752 st->print_cr(INTPTR_FORMAT " is pointing into interpreter code"
753 " (not bytecode specific)", addr);
754 return;
755 }
756 //
757 if (AdapterHandlerLibrary::contains(b)) {
758 st->print_cr("Printing AdapterHandler");
759 AdapterHandlerLibrary::print_handler_on(st, b);
760 }
761 // the stubroutines are generated into a buffer blob
762 StubCodeDesc* d = StubCodeDesc::desc_for(addr);
763 if (d != NULL) {
764 d->print_on(st);
765 if (print_pc) st->cr();
766 return;
767 }
768 if (StubRoutines::contains(addr)) {
769 st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) "
770 "stub routine", addr);
771 return;
772 }
773 // the InlineCacheBuffer is using stubs generated into a buffer blob
774 if (InlineCacheBuffer::contains(addr)) {
775 st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", addr);
776 return;
777 }
778 VtableStub* v = VtableStubs::stub_containing(addr);
779 if (v != NULL) {
780 v->print_on(st);
781 return;
782 }
783 }
784 if (print_pc && b->is_nmethod()) {
785 ResourceMark rm;
786 st->print("%#p: Compiled ", addr);
787 ((nmethod*)b)->method()->print_value_on(st);
788 st->print(" = (CodeBlob*)" INTPTR_FORMAT, b);
789 st->cr();
790 return;
791 }
792 if ( b->is_nmethod()) {
793 if (b->is_zombie()) {
794 st->print_cr(INTPTR_FORMAT " is zombie nmethod", b);
795 } else if (b->is_not_entrant()) {
796 st->print_cr(INTPTR_FORMAT " is non-entrant nmethod", b);
797 }
798 }
799 b->print_on(st);
800 return;
801 }
802
803 if (Universe::heap()->is_in(addr)) {
804 HeapWord* p = Universe::heap()->block_start(addr);
805 bool print = false;
806 // If we couldn't find it it just may mean that heap wasn't parseable
807 // See if we were just given an oop directly
808 if (p != NULL && Universe::heap()->block_is_obj(p)) {
809 print = true;
810 } else if (p == NULL && ((oopDesc*)addr)->is_oop()) {
811 p = (HeapWord*) addr;
812 print = true;
813 }
814 if (print) {
815 oop(p)->print_on(st);
816 if (p != (HeapWord*)x && oop(p)->is_constMethod() &&
817 constMethodOop(p)->contains(addr)) {
818 Thread *thread = Thread::current();
819 HandleMark hm(thread);
820 methodHandle mh (thread, constMethodOop(p)->method());
821 if (!mh->is_native()) {
822 st->print_cr("bci_from(%p) = %d; print_codes():",
823 addr, mh->bci_from(address(x)));
824 mh->print_codes_on(st);
825 }
826 }
827 return;
828 }
829 } else {
830 if (Universe::heap()->is_in_reserved(addr)) {
831 st->print_cr(INTPTR_FORMAT " is an unallocated location "
832 "in the heap", addr);
833 return;
834 }
835 }
836 if (JNIHandles::is_global_handle((jobject) addr)) {
837 st->print_cr(INTPTR_FORMAT " is a global jni handle", addr);
838 return;
839 }
840 if (JNIHandles::is_weak_global_handle((jobject) addr)) {
841 st->print_cr(INTPTR_FORMAT " is a weak global jni handle", addr);
842 return;
843 }
844 #ifndef PRODUCT
845 // we don't keep the block list in product mode
846 if (JNIHandleBlock::any_contains((jobject) addr)) {
847 st->print_cr(INTPTR_FORMAT " is a local jni handle", addr);
848 return;
849 }
850 #endif
851
852 for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
853 // Check for privilege stack
854 if (thread->privileged_stack_top() != NULL &&
855 thread->privileged_stack_top()->contains(addr)) {
856 st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack "
857 "for thread: " INTPTR_FORMAT, addr, thread);
858 thread->print_on(st);
859 return;
860 }
861 // If the addr is a java thread print information about that.
862 if (addr == (address)thread) {
863 thread->print_on(st);
864 return;
865 }
866 // If the addr is in the stack region for this thread then report that
867 // and print thread info
868 if (thread->stack_base() >= addr &&
869 addr > (thread->stack_base() - thread->stack_size())) {
870 st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
871 INTPTR_FORMAT, addr, thread);
872 thread->print_on(st);
873 return;
874 }
875
876 }
877 // Try an OS specific find
878 if (os::find(addr, st)) {
879 return;
880 }
881
882 st->print_cr(INTPTR_FORMAT " is pointing to unknown location", addr);
883 }
884
885 // Looks like all platforms except IA64 can use the same function to check
886 // if C stack is walkable beyond current frame. The check for fp() is not
887 // necessary on Sparc, but it's harmless.
888 bool os::is_first_C_frame(frame* fr) {
889 #ifdef IA64
890 // In order to walk native frames on Itanium, we need to access the unwind
891 // table, which is inside ELF. We don't want to parse ELF after fatal error,
892 // so return true for IA64. If we need to support C stack walking on IA64,
893 // this function needs to be moved to CPU specific files, as fp() on IA64
894 // is register stack, which grows towards higher memory address.
895 return true;
896 #endif
897
898 // Load up sp, fp, sender sp and sender fp, check for reasonable values.
899 // Check usp first, because if that's bad the other accessors may fault
900 // on some architectures. Ditto ufp second, etc.
901 uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
902 // sp on amd can be 32 bit aligned.
903 uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
904
905 uintptr_t usp = (uintptr_t)fr->sp();
906 if ((usp & sp_align_mask) != 0) return true;
907
908 uintptr_t ufp = (uintptr_t)fr->fp();
909 if ((ufp & fp_align_mask) != 0) return true;
910
911 uintptr_t old_sp = (uintptr_t)fr->sender_sp();
912 if ((old_sp & sp_align_mask) != 0) return true;
913 if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
914
915 uintptr_t old_fp = (uintptr_t)fr->link();
916 if ((old_fp & fp_align_mask) != 0) return true;
917 if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
918
919 // stack grows downwards; if old_fp is below current fp or if the stack
920 // frame is too large, either the stack is corrupted or fp is not saved
921 // on stack (i.e. on x86, ebp may be used as general register). The stack
922 // is not walkable beyond current frame.
923 if (old_fp < ufp) return true;
924 if (old_fp - ufp > 64 * K) return true;
925
926 return false;
927 }
928
929 #ifdef ASSERT
930 extern "C" void test_random() {
931 const double m = 2147483647;
932 double mean = 0.0, variance = 0.0, t;
933 long reps = 10000;
934 unsigned long seed = 1;
935
936 tty->print_cr("seed %ld for %ld repeats...", seed, reps);
937 os::init_random(seed);
938 long num;
939 for (int k = 0; k < reps; k++) {
940 num = os::random();
941 double u = (double)num / m;
942 assert(u >= 0.0 && u <= 1.0, "bad random number!");
943
944 // calculate mean and variance of the random sequence
945 mean += u;
946 variance += (u*u);
947 }
948 mean /= reps;
949 variance /= (reps - 1);
950
951 assert(num == 1043618065, "bad seed");
952 tty->print_cr("mean of the 1st 10000 numbers: %f", mean);
953 tty->print_cr("variance of the 1st 10000 numbers: %f", variance);
954 const double eps = 0.0001;
955 t = fabsd(mean - 0.5018);
956 assert(t < eps, "bad mean");
957 t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355;
958 assert(t < eps, "bad variance");
959 }
960 #endif
961
962
963 // Set up the boot classpath.
964
965 char* os::format_boot_path(const char* format_string,
966 const char* home,
967 int home_len,
968 char fileSep,
969 char pathSep) {
970 assert((fileSep == '/' && pathSep == ':') ||
971 (fileSep == '\\' && pathSep == ';'), "unexpected seperator chars");
972
973 // Scan the format string to determine the length of the actual
974 // boot classpath, and handle platform dependencies as well.
975 int formatted_path_len = 0;
976 const char* p;
977 for (p = format_string; *p != 0; ++p) {
978 if (*p == '%') formatted_path_len += home_len - 1;
979 ++formatted_path_len;
980 }
981
982 char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1);
983 if (formatted_path == NULL) {
984 return NULL;
985 }
986
987 // Create boot classpath from format, substituting separator chars and
988 // java home directory.
989 char* q = formatted_path;
990 for (p = format_string; *p != 0; ++p) {
991 switch (*p) {
992 case '%':
993 strcpy(q, home);
994 q += home_len;
995 break;
996 case '/':
997 *q++ = fileSep;
998 break;
999 case ':':
1000 *q++ = pathSep;
1001 break;
1002 default:
1003 *q++ = *p;
1004 }
1005 }
1006 *q = '\0';
1007
1008 assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
1009 return formatted_path;
1010 }
1011
1012
1013 bool os::set_boot_path(char fileSep, char pathSep) {
1014 const char* home = Arguments::get_java_home();
1015 int home_len = (int)strlen(home);
1016
1017 static const char* meta_index_dir_format = "%/lib/";
1018 static const char* meta_index_format = "%/lib/meta-index";
1019 char* meta_index = format_boot_path(meta_index_format, home, home_len, fileSep, pathSep);
1020 if (meta_index == NULL) return false;
1021 char* meta_index_dir = format_boot_path(meta_index_dir_format, home, home_len, fileSep, pathSep);
1022 if (meta_index_dir == NULL) return false;
1023 Arguments::set_meta_index_path(meta_index, meta_index_dir);
1024
1025 // Any modification to the JAR-file list, for the boot classpath must be
1026 // aligned with install/install/make/common/Pack.gmk. Note: boot class
1027 // path class JARs, are stripped for StackMapTable to reduce download size.
1028 static const char classpath_format[] =
1029 "%/lib/resources.jar:"
1030 "%/lib/rt.jar:"
1031 "%/lib/sunrsasign.jar:"
1032 "%/lib/jsse.jar:"
1033 "%/lib/jce.jar:"
1034 "%/lib/charsets.jar:"
1035
1036 // ## TEMPORARY hack to keep the legacy launcher working when
1037 // ## only the boot module is installed (cf. j.l.ClassLoader)
1038 "%/lib/modules/jdk.boot.jar:"
1039
1040 "%/classes";
1041 char* sysclasspath = format_boot_path(classpath_format, home, home_len, fileSep, pathSep);
1042 if (sysclasspath == NULL) return false;
1043 Arguments::set_sysclasspath(sysclasspath);
1044
1045 return true;
1046 }
1047
1048 /*
1049 * Splits a path, based on its separator, the number of
1050 * elements is returned back in n.
1051 * It is the callers responsibility to:
1052 * a> check the value of n, and n may be 0.
1053 * b> ignore any empty path elements
1054 * c> free up the data.
1055 */
1056 char** os::split_path(const char* path, int* n) {
1057 *n = 0;
1058 if (path == NULL || strlen(path) == 0) {
1059 return NULL;
1060 }
1061 const char psepchar = *os::path_separator();
1062 char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1);
1063 if (inpath == NULL) {
1064 return NULL;
1065 }
1066 strncpy(inpath, path, strlen(path));
1067 int count = 1;
1068 char* p = strchr(inpath, psepchar);
1069 // Get a count of elements to allocate memory
1070 while (p != NULL) {
1071 count++;
1072 p++;
1073 p = strchr(p, psepchar);
1074 }
1075 char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count);
1076 if (opath == NULL) {
1077 return NULL;
1078 }
1079
1080 // do the actual splitting
1081 p = inpath;
1082 for (int i = 0 ; i < count ; i++) {
1083 size_t len = strcspn(p, os::path_separator());
1084 if (len > JVM_MAXPATHLEN) {
1085 return NULL;
1086 }
1087 // allocate the string and add terminator storage
1088 char* s = (char*)NEW_C_HEAP_ARRAY(char, len + 1);
1089 if (s == NULL) {
1090 return NULL;
1091 }
1092 strncpy(s, p, len);
1093 s[len] = '\0';
1094 opath[i] = s;
1095 p += len + 1;
1096 }
1097 FREE_C_HEAP_ARRAY(char, inpath);
1098 *n = count;
1099 return opath;
1100 }
1101
1102 void os::set_memory_serialize_page(address page) {
1103 int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64);
1104 _mem_serialize_page = (volatile int32_t *)page;
1105 // We initialize the serialization page shift count here
1106 // We assume a cache line size of 64 bytes
1107 assert(SerializePageShiftCount == count,
1108 "thread size changed, fix SerializePageShiftCount constant");
1109 set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t)));
1110 }
1111
1112 static volatile intptr_t SerializePageLock = 0;
1113
1114 // This method is called from signal handler when SIGSEGV occurs while the current
1115 // thread tries to store to the "read-only" memory serialize page during state
1116 // transition.
1117 void os::block_on_serialize_page_trap() {
1118 if (TraceSafepoint) {
1119 tty->print_cr("Block until the serialize page permission restored");
1120 }
1121 // When VMThread is holding the SerializePageLock during modifying the
1122 // access permission of the memory serialize page, the following call
1123 // will block until the permission of that page is restored to rw.
1124 // Generally, it is unsafe to manipulate locks in signal handlers, but in
1125 // this case, it's OK as the signal is synchronous and we know precisely when
1126 // it can occur.
1127 Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page");
1128 Thread::muxRelease(&SerializePageLock);
1129 }
1130
1131 // Serialize all thread state variables
1132 void os::serialize_thread_states() {
1133 // On some platforms such as Solaris & Linux, the time duration of the page
1134 // permission restoration is observed to be much longer than expected due to
1135 // scheduler starvation problem etc. To avoid the long synchronization
1136 // time and expensive page trap spinning, 'SerializePageLock' is used to block
1137 // the mutator thread if such case is encountered. See bug 6546278 for details.
1138 Thread::muxAcquire(&SerializePageLock, "serialize_thread_states");
1139 os::protect_memory((char *)os::get_memory_serialize_page(),
1140 os::vm_page_size(), MEM_PROT_READ);
1141 os::protect_memory((char *)os::get_memory_serialize_page(),
1142 os::vm_page_size(), MEM_PROT_RW);
1143 Thread::muxRelease(&SerializePageLock);
1144 }
1145
1146 // Returns true if the current stack pointer is above the stack shadow
1147 // pages, false otherwise.
1148
1149 bool os::stack_shadow_pages_available(Thread *thread, methodHandle method) {
1150 assert(StackRedPages > 0 && StackYellowPages > 0,"Sanity check");
1151 address sp = current_stack_pointer();
1152 // Check if we have StackShadowPages above the yellow zone. This parameter
1153 // is dependent on the depth of the maximum VM call stack possible from
1154 // the handler for stack overflow. 'instanceof' in the stack overflow
1155 // handler or a println uses at least 8k stack of VM and native code
1156 // respectively.
1157 const int framesize_in_bytes =
1158 Interpreter::size_top_interpreter_activation(method()) * wordSize;
1159 int reserved_area = ((StackShadowPages + StackRedPages + StackYellowPages)
1160 * vm_page_size()) + framesize_in_bytes;
1161 // The very lower end of the stack
1162 address stack_limit = thread->stack_base() - thread->stack_size();
1163 return (sp > (stack_limit + reserved_area));
1164 }
1165
1166 size_t os::page_size_for_region(size_t region_min_size, size_t region_max_size,
1167 uint min_pages)
1168 {
1169 assert(min_pages > 0, "sanity");
1170 if (UseLargePages) {
1171 const size_t max_page_size = region_max_size / min_pages;
1172
1173 for (unsigned int i = 0; _page_sizes[i] != 0; ++i) {
1174 const size_t sz = _page_sizes[i];
1175 const size_t mask = sz - 1;
1176 if ((region_min_size & mask) == 0 && (region_max_size & mask) == 0) {
1177 // The largest page size with no fragmentation.
1178 return sz;
1179 }
1180
1181 if (sz <= max_page_size) {
1182 // The largest page size that satisfies the min_pages requirement.
1183 return sz;
1184 }
1185 }
1186 }
1187
1188 return vm_page_size();
1189 }
1190
1191 #ifndef PRODUCT
1192 void os::trace_page_sizes(const char* str, const size_t region_min_size,
1193 const size_t region_max_size, const size_t page_size,
1194 const char* base, const size_t size)
1195 {
1196 if (TracePageSizes) {
1197 tty->print_cr("%s: min=" SIZE_FORMAT " max=" SIZE_FORMAT
1198 " pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT
1199 " size=" SIZE_FORMAT,
1200 str, region_min_size, region_max_size,
1201 page_size, base, size);
1202 }
1203 }
1204 #endif // #ifndef PRODUCT
1205
1206 // This is the working definition of a server class machine:
1207 // >= 2 physical CPU's and >=2GB of memory, with some fuzz
1208 // because the graphics memory (?) sometimes masks physical memory.
1209 // If you want to change the definition of a server class machine
1210 // on some OS or platform, e.g., >=4GB on Windohs platforms,
1211 // then you'll have to parameterize this method based on that state,
1212 // as was done for logical processors here, or replicate and
1213 // specialize this method for each platform. (Or fix os to have
1214 // some inheritance structure and use subclassing. Sigh.)
1215 // If you want some platform to always or never behave as a server
1216 // class machine, change the setting of AlwaysActAsServerClassMachine
1217 // and NeverActAsServerClassMachine in globals*.hpp.
1218 bool os::is_server_class_machine() {
1219 // First check for the early returns
1220 if (NeverActAsServerClassMachine) {
1221 return false;
1222 }
1223 if (AlwaysActAsServerClassMachine) {
1224 return true;
1225 }
1226 // Then actually look at the machine
1227 bool result = false;
1228 const unsigned int server_processors = 2;
1229 const julong server_memory = 2UL * G;
1230 // We seem not to get our full complement of memory.
1231 // We allow some part (1/8?) of the memory to be "missing",
1232 // based on the sizes of DIMMs, and maybe graphics cards.
1233 const julong missing_memory = 256UL * M;
1234
1235 /* Is this a server class machine? */
1236 if ((os::active_processor_count() >= (int)server_processors) &&
1237 (os::physical_memory() >= (server_memory - missing_memory))) {
1238 const unsigned int logical_processors =
1239 VM_Version::logical_processors_per_package();
1240 if (logical_processors > 1) {
1241 const unsigned int physical_packages =
1242 os::active_processor_count() / logical_processors;
1243 if (physical_packages > server_processors) {
1244 result = true;
1245 }
1246 } else {
1247 result = true;
1248 }
1249 }
1250 return result;
1251 }