1 /*
2 * Copyright (c) 1997, 2018, 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/vmGCOperations.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 #ifdef ASSERT
42 #include "memory/guardedMemory.hpp"
43 #endif
44 #include "memory/resourceArea.hpp"
45 #include "oops/instanceKlass.inline.hpp"
46 #include "oops/oop.inline.hpp"
47 #include "prims/jvm_misc.hpp"
48 #include "prims/privilegedStack.hpp"
49 #include "runtime/arguments.hpp"
50 #include "runtime/atomic.hpp"
51 #include "runtime/frame.inline.hpp"
52 #include "runtime/interfaceSupport.hpp"
53 #include "runtime/java.hpp"
54 #include "runtime/javaCalls.hpp"
55 #include "runtime/mutexLocker.hpp"
56 #include "runtime/os.inline.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 int32_t* os::_mem_serialize_page = NULL;
76 uintptr_t os::_serialize_page_mask = 0;
77 volatile unsigned int os::_rand_seed = 1;
78 int os::_processor_count = 0;
79 int os::_initial_active_processor_count = 0;
80 size_t os::_page_sizes[os::page_sizes_max];
81
82 #ifndef PRODUCT
83 julong os::num_mallocs = 0; // # of calls to malloc/realloc
84 julong os::alloc_bytes = 0; // # of bytes allocated
85 julong os::num_frees = 0; // # of calls to free
86 julong os::free_bytes = 0; // # of bytes freed
87 #endif
88
89 static size_t cur_malloc_words = 0; // current size for MallocMaxTestWords
90
91 void os_init_globals() {
92 // Called from init_globals().
93 // See Threads::create_vm() in thread.cpp, and init.cpp.
94 os::init_globals();
95 }
96
97 static time_t get_timezone(const struct tm* time_struct) {
98 #if defined(_ALLBSD_SOURCE)
99 return time_struct->tm_gmtoff;
100 #elif defined(_WINDOWS)
101 long zone;
102 _get_timezone(&zone);
103 return static_cast<time_t>(zone);
104 #else
105 return timezone;
106 #endif
107 }
108
109 int os::snprintf(char* buf, size_t len, const char* fmt, ...) {
110 va_list args;
111 va_start(args, fmt);
112 int result = os::vsnprintf(buf, len, fmt, args);
113 va_end(args);
114 return result;
115 }
116
117 // Fill in buffer with current local time as an ISO-8601 string.
118 // E.g., yyyy-mm-ddThh:mm:ss-zzzz.
119 // Returns buffer, or NULL if it failed.
120 // This would mostly be a call to
121 // strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
122 // except that on Windows the %z behaves badly, so we do it ourselves.
123 // Also, people wanted milliseconds on there,
124 // and strftime doesn't do milliseconds.
125 char* os::iso8601_time(char* buffer, size_t buffer_length, bool utc) {
126 // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
127 // 1 2
128 // 12345678901234567890123456789
129 // format string: "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d"
130 static const size_t needed_buffer = 29;
131
132 // Sanity check the arguments
133 if (buffer == NULL) {
134 assert(false, "NULL buffer");
135 return NULL;
136 }
137 if (buffer_length < needed_buffer) {
138 assert(false, "buffer_length too small");
139 return NULL;
140 }
141 // Get the current time
142 jlong milliseconds_since_19700101 = javaTimeMillis();
143 const int milliseconds_per_microsecond = 1000;
144 const time_t seconds_since_19700101 =
145 milliseconds_since_19700101 / milliseconds_per_microsecond;
146 const int milliseconds_after_second =
147 milliseconds_since_19700101 % milliseconds_per_microsecond;
148 // Convert the time value to a tm and timezone variable
149 struct tm time_struct;
150 if (utc) {
151 if (gmtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
152 assert(false, "Failed gmtime_pd");
153 return NULL;
154 }
155 } else {
156 if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
157 assert(false, "Failed localtime_pd");
158 return NULL;
159 }
160 }
161 const time_t zone = get_timezone(&time_struct);
162
163 // If daylight savings time is in effect,
164 // we are 1 hour East of our time zone
165 const time_t seconds_per_minute = 60;
166 const time_t minutes_per_hour = 60;
167 const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
168 time_t UTC_to_local = zone;
169 if (time_struct.tm_isdst > 0) {
170 UTC_to_local = UTC_to_local - seconds_per_hour;
171 }
172
173 // No offset when dealing with UTC
174 if (utc) {
175 UTC_to_local = 0;
176 }
177
178 // Compute the time zone offset.
179 // localtime_pd() sets timezone to the difference (in seconds)
180 // between UTC and and local time.
181 // ISO 8601 says we need the difference between local time and UTC,
182 // we change the sign of the localtime_pd() result.
183 const time_t local_to_UTC = -(UTC_to_local);
184 // Then we have to figure out if if we are ahead (+) or behind (-) UTC.
185 char sign_local_to_UTC = '+';
186 time_t abs_local_to_UTC = local_to_UTC;
187 if (local_to_UTC < 0) {
188 sign_local_to_UTC = '-';
189 abs_local_to_UTC = -(abs_local_to_UTC);
190 }
191 // Convert time zone offset seconds to hours and minutes.
192 const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
193 const time_t zone_min =
194 ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
195
196 // Print an ISO 8601 date and time stamp into the buffer
197 const int year = 1900 + time_struct.tm_year;
198 const int month = 1 + time_struct.tm_mon;
199 const int printed = jio_snprintf(buffer, buffer_length,
200 "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d",
201 year,
202 month,
203 time_struct.tm_mday,
204 time_struct.tm_hour,
205 time_struct.tm_min,
206 time_struct.tm_sec,
207 milliseconds_after_second,
208 sign_local_to_UTC,
209 zone_hours,
210 zone_min);
211 if (printed == 0) {
212 assert(false, "Failed jio_printf");
213 return NULL;
214 }
215 return buffer;
216 }
217
218 OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
219 debug_only(Thread::check_for_dangling_thread_pointer(thread);)
220
221 if (p >= MinPriority && p <= MaxPriority) {
222 int priority = java_to_os_priority[p];
223 return set_native_priority(thread, priority);
224 } else {
225 assert(false, "Should not happen");
226 return OS_ERR;
227 }
228 }
229
230 // The mapping from OS priority back to Java priority may be inexact because
231 // Java priorities can map M:1 with native priorities. If you want the definite
232 // Java priority then use JavaThread::java_priority()
233 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
234 int p;
235 int os_prio;
236 OSReturn ret = get_native_priority(thread, &os_prio);
237 if (ret != OS_OK) return ret;
238
239 if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) {
240 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
241 } else {
242 // niceness values are in reverse order
243 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] < os_prio; p--) ;
244 }
245 priority = (ThreadPriority)p;
246 return OS_OK;
247 }
248
249 bool os::dll_build_name(char* buffer, size_t size, const char* fname) {
250 int n = jio_snprintf(buffer, size, "%s%s%s", JNI_LIB_PREFIX, fname, JNI_LIB_SUFFIX);
251 return (n != -1);
252 }
253
254 // Helper for dll_locate_lib.
255 // Pass buffer and printbuffer as we already printed the path to buffer
256 // when we called get_current_directory. This way we avoid another buffer
257 // of size MAX_PATH.
258 static bool conc_path_file_and_check(char *buffer, char *printbuffer, size_t printbuflen,
259 const char* pname, char lastchar, const char* fname) {
260
261 // Concatenate path and file name, but don't print double path separators.
262 const char *filesep = (WINDOWS_ONLY(lastchar == ':' ||) lastchar == os::file_separator()[0]) ?
263 "" : os::file_separator();
264 int ret = jio_snprintf(printbuffer, printbuflen, "%s%s%s", pname, filesep, fname);
265 // Check whether file exists.
266 if (ret != -1) {
267 struct stat statbuf;
268 return os::stat(buffer, &statbuf) == 0;
269 }
270 return false;
271 }
272
273 bool os::dll_locate_lib(char *buffer, size_t buflen,
274 const char* pname, const char* fname) {
275 bool retval = false;
276
277 size_t fullfnamelen = strlen(JNI_LIB_PREFIX) + strlen(fname) + strlen(JNI_LIB_SUFFIX);
278 char* fullfname = (char*)NEW_C_HEAP_ARRAY(char, fullfnamelen + 1, mtInternal);
279 if (dll_build_name(fullfname, fullfnamelen + 1, fname)) {
280 const size_t pnamelen = pname ? strlen(pname) : 0;
281
282 if (pnamelen == 0) {
283 // If no path given, use current working directory.
284 const char* p = get_current_directory(buffer, buflen);
285 if (p != NULL) {
286 const size_t plen = strlen(buffer);
287 const char lastchar = buffer[plen - 1];
288 retval = conc_path_file_and_check(buffer, &buffer[plen], buflen - plen,
289 "", lastchar, fullfname);
290 }
291 } else if (strchr(pname, *os::path_separator()) != NULL) {
292 // A list of paths. Search for the path that contains the library.
293 int n;
294 char** pelements = split_path(pname, &n);
295 if (pelements != NULL) {
296 for (int i = 0; i < n; i++) {
297 char* path = pelements[i];
298 // Really shouldn't be NULL, but check can't hurt.
299 size_t plen = (path == NULL) ? 0 : strlen(path);
300 if (plen == 0) {
301 continue; // Skip the empty path values.
302 }
303 const char lastchar = path[plen - 1];
304 retval = conc_path_file_and_check(buffer, buffer, buflen, path, lastchar, fullfname);
305 if (retval) break;
306 }
307 // Release the storage allocated by split_path.
308 for (int i = 0; i < n; i++) {
309 if (pelements[i] != NULL) {
310 FREE_C_HEAP_ARRAY(char, pelements[i]);
311 }
312 }
313 FREE_C_HEAP_ARRAY(char*, pelements);
314 }
315 } else {
316 // A definite path.
317 const char lastchar = pname[pnamelen-1];
318 retval = conc_path_file_and_check(buffer, buffer, buflen, pname, lastchar, fullfname);
319 }
320 }
321
322 FREE_C_HEAP_ARRAY(char*, fullfname);
323 return retval;
324 }
325
326 // --------------------- sun.misc.Signal (optional) ---------------------
327
328
329 // SIGBREAK is sent by the keyboard to query the VM state
330 #ifndef SIGBREAK
331 #define SIGBREAK SIGQUIT
332 #endif
333
334 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
335
336
337 static void signal_thread_entry(JavaThread* thread, TRAPS) {
338 os::set_priority(thread, NearMaxPriority);
339 while (true) {
340 int sig;
341 {
342 // FIXME : Currently we have not decided what should be the status
343 // for this java thread blocked here. Once we decide about
344 // that we should fix this.
345 sig = os::signal_wait();
346 }
347 if (sig == os::sigexitnum_pd()) {
348 // Terminate the signal thread
349 return;
350 }
351
352 switch (sig) {
353 case SIGBREAK: {
354 // Check if the signal is a trigger to start the Attach Listener - in that
355 // case don't print stack traces.
356 if (!DisableAttachMechanism && AttachListener::is_init_trigger()) {
357 continue;
358 }
359 // Print stack traces
360 // Any SIGBREAK operations added here should make sure to flush
361 // the output stream (e.g. tty->flush()) after output. See 4803766.
362 // Each module also prints an extra carriage return after its output.
363 VM_PrintThreads op;
364 VMThread::execute(&op);
365 VM_PrintJNI jni_op;
366 VMThread::execute(&jni_op);
367 VM_FindDeadlocks op1(tty);
368 VMThread::execute(&op1);
369 Universe::print_heap_at_SIGBREAK();
370 if (PrintClassHistogram) {
371 VM_GC_HeapInspection op1(tty, true /* force full GC before heap inspection */);
372 VMThread::execute(&op1);
373 }
374 if (JvmtiExport::should_post_data_dump()) {
375 JvmtiExport::post_data_dump();
376 }
377 break;
378 }
379 default: {
380 // Dispatch the signal to java
381 HandleMark hm(THREAD);
382 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_misc_Signal(), THREAD);
383 if (klass != NULL) {
384 JavaValue result(T_VOID);
385 JavaCallArguments args;
386 args.push_int(sig);
387 JavaCalls::call_static(
388 &result,
389 klass,
390 vmSymbols::dispatch_name(),
391 vmSymbols::int_void_signature(),
392 &args,
393 THREAD
394 );
395 }
396 if (HAS_PENDING_EXCEPTION) {
397 // tty is initialized early so we don't expect it to be null, but
398 // if it is we can't risk doing an initialization that might
399 // trigger additional out-of-memory conditions
400 if (tty != NULL) {
401 char klass_name[256];
402 char tmp_sig_name[16];
403 const char* sig_name = "UNKNOWN";
404 InstanceKlass::cast(PENDING_EXCEPTION->klass())->
405 name()->as_klass_external_name(klass_name, 256);
406 if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
407 sig_name = tmp_sig_name;
408 warning("Exception %s occurred dispatching signal %s to handler"
409 "- the VM may need to be forcibly terminated",
410 klass_name, sig_name );
411 }
412 CLEAR_PENDING_EXCEPTION;
413 }
414 }
415 }
416 }
417 }
418
419 void os::init_before_ergo() {
420 initialize_initial_active_processor_count();
421 // We need to initialize large page support here because ergonomics takes some
422 // decisions depending on large page support and the calculated large page size.
423 large_page_init();
424
425 // We need to adapt the configured number of stack protection pages given
426 // in 4K pages to the actual os page size. We must do this before setting
427 // up minimal stack sizes etc. in os::init_2().
428 JavaThread::set_stack_red_zone_size (align_up(StackRedPages * 4 * K, vm_page_size()));
429 JavaThread::set_stack_yellow_zone_size (align_up(StackYellowPages * 4 * K, vm_page_size()));
430 JavaThread::set_stack_reserved_zone_size(align_up(StackReservedPages * 4 * K, vm_page_size()));
431 JavaThread::set_stack_shadow_zone_size (align_up(StackShadowPages * 4 * K, vm_page_size()));
432
433 // VM version initialization identifies some characteristics of the
434 // platform that are used during ergonomic decisions.
435 VM_Version::init_before_ergo();
436 }
437
438 void os::signal_init(TRAPS) {
439 if (!ReduceSignalUsage) {
440 // Setup JavaThread for processing signals
441 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
442 InstanceKlass* ik = InstanceKlass::cast(k);
443 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
444
445 const char thread_name[] = "Signal Dispatcher";
446 Handle string = java_lang_String::create_from_str(thread_name, CHECK);
447
448 // Initialize thread_oop to put it into the system threadGroup
449 Handle thread_group (THREAD, Universe::system_thread_group());
450 JavaValue result(T_VOID);
451 JavaCalls::call_special(&result, thread_oop,
452 ik,
453 vmSymbols::object_initializer_name(),
454 vmSymbols::threadgroup_string_void_signature(),
455 thread_group,
456 string,
457 CHECK);
458
459 Klass* group = SystemDictionary::ThreadGroup_klass();
460 JavaCalls::call_special(&result,
461 thread_group,
462 group,
463 vmSymbols::add_method_name(),
464 vmSymbols::thread_void_signature(),
465 thread_oop, // ARG 1
466 CHECK);
467
468 os::signal_init_pd();
469
470 { MutexLocker mu(Threads_lock);
471 JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
472
473 // At this point it may be possible that no osthread was created for the
474 // JavaThread due to lack of memory. We would have to throw an exception
475 // in that case. However, since this must work and we do not allow
476 // exceptions anyway, check and abort if this fails.
477 if (signal_thread == NULL || signal_thread->osthread() == NULL) {
478 vm_exit_during_initialization("java.lang.OutOfMemoryError",
479 os::native_thread_creation_failed_msg());
480 }
481
482 java_lang_Thread::set_thread(thread_oop(), signal_thread);
483 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
484 java_lang_Thread::set_daemon(thread_oop());
485
486 signal_thread->set_threadObj(thread_oop());
487 Threads::add(signal_thread);
488 Thread::start(signal_thread);
489 }
490 // Handle ^BREAK
491 os::signal(SIGBREAK, os::user_handler());
492 }
493 }
494
495
496 void os::terminate_signal_thread() {
497 if (!ReduceSignalUsage)
498 signal_notify(sigexitnum_pd());
499 }
500
501
502 // --------------------- loading libraries ---------------------
503
504 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
505 extern struct JavaVM_ main_vm;
506
507 static void* _native_java_library = NULL;
508
509 void* os::native_java_library() {
510 if (_native_java_library == NULL) {
511 char buffer[JVM_MAXPATHLEN];
512 char ebuf[1024];
513
514 // Try to load verify dll first. In 1.3 java dll depends on it and is not
515 // always able to find it when the loading executable is outside the JDK.
516 // In order to keep working with 1.2 we ignore any loading errors.
517 if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
518 "verify")) {
519 dll_load(buffer, ebuf, sizeof(ebuf));
520 }
521
522 // Load java dll
523 if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
524 "java")) {
525 _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
526 }
527 if (_native_java_library == NULL) {
528 vm_exit_during_initialization("Unable to load native library", ebuf);
529 }
530
531 #if defined(__OpenBSD__)
532 // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so
533 // ignore errors
534 if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
535 "net")) {
536 dll_load(buffer, ebuf, sizeof(ebuf));
537 }
538 #endif
539 }
540 return _native_java_library;
541 }
542
543 /*
544 * Support for finding Agent_On(Un)Load/Attach<_lib_name> if it exists.
545 * If check_lib == true then we are looking for an
546 * Agent_OnLoad_lib_name or Agent_OnAttach_lib_name function to determine if
547 * this library is statically linked into the image.
548 * If check_lib == false then we will look for the appropriate symbol in the
549 * executable if agent_lib->is_static_lib() == true or in the shared library
550 * referenced by 'handle'.
551 */
552 void* os::find_agent_function(AgentLibrary *agent_lib, bool check_lib,
553 const char *syms[], size_t syms_len) {
554 assert(agent_lib != NULL, "sanity check");
555 const char *lib_name;
556 void *handle = agent_lib->os_lib();
557 void *entryName = NULL;
558 char *agent_function_name;
559 size_t i;
560
561 // If checking then use the agent name otherwise test is_static_lib() to
562 // see how to process this lookup
563 lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : NULL);
564 for (i = 0; i < syms_len; i++) {
565 agent_function_name = build_agent_function_name(syms[i], lib_name, agent_lib->is_absolute_path());
566 if (agent_function_name == NULL) {
567 break;
568 }
569 entryName = dll_lookup(handle, agent_function_name);
570 FREE_C_HEAP_ARRAY(char, agent_function_name);
571 if (entryName != NULL) {
572 break;
573 }
574 }
575 return entryName;
576 }
577
578 // See if the passed in agent is statically linked into the VM image.
579 bool os::find_builtin_agent(AgentLibrary *agent_lib, const char *syms[],
580 size_t syms_len) {
581 void *ret;
582 void *proc_handle;
583 void *save_handle;
584
585 assert(agent_lib != NULL, "sanity check");
586 if (agent_lib->name() == NULL) {
587 return false;
588 }
589 proc_handle = get_default_process_handle();
590 // Check for Agent_OnLoad/Attach_lib_name function
591 save_handle = agent_lib->os_lib();
592 // We want to look in this process' symbol table.
593 agent_lib->set_os_lib(proc_handle);
594 ret = find_agent_function(agent_lib, true, syms, syms_len);
595 if (ret != NULL) {
596 // Found an entry point like Agent_OnLoad_lib_name so we have a static agent
597 agent_lib->set_valid();
598 agent_lib->set_static_lib(true);
599 return true;
600 }
601 agent_lib->set_os_lib(save_handle);
602 return false;
603 }
604
605 // --------------------- heap allocation utilities ---------------------
606
607 char *os::strdup(const char *str, MEMFLAGS flags) {
608 size_t size = strlen(str);
609 char *dup_str = (char *)malloc(size + 1, flags);
610 if (dup_str == NULL) return NULL;
611 strcpy(dup_str, str);
612 return dup_str;
613 }
614
615 char* os::strdup_check_oom(const char* str, MEMFLAGS flags) {
616 char* p = os::strdup(str, flags);
617 if (p == NULL) {
618 vm_exit_out_of_memory(strlen(str) + 1, OOM_MALLOC_ERROR, "os::strdup_check_oom");
619 }
620 return p;
621 }
622
623
624 #define paranoid 0 /* only set to 1 if you suspect checking code has bug */
625
626 #ifdef ASSERT
627
628 static void verify_memory(void* ptr) {
629 GuardedMemory guarded(ptr);
630 if (!guarded.verify_guards()) {
631 LogTarget(Warning, malloc, free) lt;
632 ResourceMark rm;
633 LogStream ls(lt);
634 ls.print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees);
635 ls.print_cr("## memory stomp:");
636 guarded.print_on(&ls);
637 fatal("memory stomping error");
638 }
639 }
640
641 #endif
642
643 //
644 // This function supports testing of the malloc out of memory
645 // condition without really running the system out of memory.
646 //
647 static bool has_reached_max_malloc_test_peak(size_t alloc_size) {
648 if (MallocMaxTestWords > 0) {
649 size_t words = (alloc_size / BytesPerWord);
650
651 if ((cur_malloc_words + words) > MallocMaxTestWords) {
652 return true;
653 }
654 Atomic::add(words, &cur_malloc_words);
655 }
656 return false;
657 }
658
659 void* os::malloc(size_t size, MEMFLAGS flags) {
660 return os::malloc(size, flags, CALLER_PC);
661 }
662
663 void* os::malloc(size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
664 NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
665 NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
666
667 // Since os::malloc can be called when the libjvm.{dll,so} is
668 // first loaded and we don't have a thread yet we must accept NULL also here.
669 assert(!os::ThreadCrashProtection::is_crash_protected(Thread::current_or_null()),
670 "malloc() not allowed when crash protection is set");
671
672 if (size == 0) {
673 // return a valid pointer if size is zero
674 // if NULL is returned the calling functions assume out of memory.
675 size = 1;
676 }
677
678 // NMT support
679 NMT_TrackingLevel level = MemTracker::tracking_level();
680 size_t nmt_header_size = MemTracker::malloc_header_size(level);
681
682 #ifndef ASSERT
683 const size_t alloc_size = size + nmt_header_size;
684 #else
685 const size_t alloc_size = GuardedMemory::get_total_size(size + nmt_header_size);
686 if (size + nmt_header_size > alloc_size) { // Check for rollover.
687 return NULL;
688 }
689 #endif
690
691 // For the test flag -XX:MallocMaxTestWords
692 if (has_reached_max_malloc_test_peak(size)) {
693 return NULL;
694 }
695
696 u_char* ptr;
697 ptr = (u_char*)::malloc(alloc_size);
698
699 #ifdef ASSERT
700 if (ptr == NULL) {
701 return NULL;
702 }
703 // Wrap memory with guard
704 GuardedMemory guarded(ptr, size + nmt_header_size);
705 ptr = guarded.get_user_ptr();
706 #endif
707 if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
708 log_warning(malloc, free)("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
709 breakpoint();
710 }
711 debug_only(if (paranoid) verify_memory(ptr));
712
713 // we do not track guard memory
714 return MemTracker::record_malloc((address)ptr, size, memflags, stack, level);
715 }
716
717 void* os::realloc(void *memblock, size_t size, MEMFLAGS flags) {
718 return os::realloc(memblock, size, flags, CALLER_PC);
719 }
720
721 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
722
723 // For the test flag -XX:MallocMaxTestWords
724 if (has_reached_max_malloc_test_peak(size)) {
725 return NULL;
726 }
727
728 if (size == 0) {
729 // return a valid pointer if size is zero
730 // if NULL is returned the calling functions assume out of memory.
731 size = 1;
732 }
733
734 #ifndef ASSERT
735 NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
736 NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
737 // NMT support
738 void* membase = MemTracker::record_free(memblock);
739 NMT_TrackingLevel level = MemTracker::tracking_level();
740 size_t nmt_header_size = MemTracker::malloc_header_size(level);
741 void* ptr = ::realloc(membase, size + nmt_header_size);
742 return MemTracker::record_malloc(ptr, size, memflags, stack, level);
743 #else
744 if (memblock == NULL) {
745 return os::malloc(size, memflags, stack);
746 }
747 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
748 log_warning(malloc, free)("os::realloc caught " PTR_FORMAT, p2i(memblock));
749 breakpoint();
750 }
751 // NMT support
752 void* membase = MemTracker::malloc_base(memblock);
753 verify_memory(membase);
754 // always move the block
755 void* ptr = os::malloc(size, memflags, stack);
756 // Copy to new memory if malloc didn't fail
757 if (ptr != NULL ) {
758 GuardedMemory guarded(MemTracker::malloc_base(memblock));
759 // Guard's user data contains NMT header
760 size_t memblock_size = guarded.get_user_size() - MemTracker::malloc_header_size(memblock);
761 memcpy(ptr, memblock, MIN2(size, memblock_size));
762 if (paranoid) verify_memory(MemTracker::malloc_base(ptr));
763 if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
764 log_warning(malloc, free)("os::realloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
765 breakpoint();
766 }
767 os::free(memblock);
768 }
769 return ptr;
770 #endif
771 }
772
773
774 void os::free(void *memblock) {
775 NOT_PRODUCT(inc_stat_counter(&num_frees, 1));
776 #ifdef ASSERT
777 if (memblock == NULL) return;
778 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
779 log_warning(malloc, free)("os::free caught " PTR_FORMAT, p2i(memblock));
780 breakpoint();
781 }
782 void* membase = MemTracker::record_free(memblock);
783 verify_memory(membase);
784
785 GuardedMemory guarded(membase);
786 size_t size = guarded.get_user_size();
787 inc_stat_counter(&free_bytes, size);
788 membase = guarded.release_for_freeing();
789 ::free(membase);
790 #else
791 void* membase = MemTracker::record_free(memblock);
792 ::free(membase);
793 #endif
794 }
795
796 void os::init_random(unsigned int initval) {
797 _rand_seed = initval;
798 }
799
800
801 static int random_helper(unsigned int rand_seed) {
802 /* standard, well-known linear congruential random generator with
803 * next_rand = (16807*seed) mod (2**31-1)
804 * see
805 * (1) "Random Number Generators: Good Ones Are Hard to Find",
806 * S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
807 * (2) "Two Fast Implementations of the 'Minimal Standard' Random
808 * Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
809 */
810 const unsigned int a = 16807;
811 const unsigned int m = 2147483647;
812 const int q = m / a; assert(q == 127773, "weird math");
813 const int r = m % a; assert(r == 2836, "weird math");
814
815 // compute az=2^31p+q
816 unsigned int lo = a * (rand_seed & 0xFFFF);
817 unsigned int hi = a * (rand_seed >> 16);
818 lo += (hi & 0x7FFF) << 16;
819
820 // if q overflowed, ignore the overflow and increment q
821 if (lo > m) {
822 lo &= m;
823 ++lo;
824 }
825 lo += hi >> 15;
826
827 // if (p+q) overflowed, ignore the overflow and increment (p+q)
828 if (lo > m) {
829 lo &= m;
830 ++lo;
831 }
832 return lo;
833 }
834
835 int os::random() {
836 // Make updating the random seed thread safe.
837 while (true) {
838 unsigned int seed = _rand_seed;
839 unsigned int rand = random_helper(seed);
840 if (Atomic::cmpxchg(rand, &_rand_seed, seed) == seed) {
841 return static_cast<int>(rand);
842 }
843 }
844 }
845
846 // The INITIALIZED state is distinguished from the SUSPENDED state because the
847 // conditions in which a thread is first started are different from those in which
848 // a suspension is resumed. These differences make it hard for us to apply the
849 // tougher checks when starting threads that we want to do when resuming them.
850 // However, when start_thread is called as a result of Thread.start, on a Java
851 // thread, the operation is synchronized on the Java Thread object. So there
852 // cannot be a race to start the thread and hence for the thread to exit while
853 // we are working on it. Non-Java threads that start Java threads either have
854 // to do so in a context in which races are impossible, or should do appropriate
855 // locking.
856
857 void os::start_thread(Thread* thread) {
858 // guard suspend/resume
859 MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
860 OSThread* osthread = thread->osthread();
861 osthread->set_state(RUNNABLE);
862 pd_start_thread(thread);
863 }
864
865 void os::abort(bool dump_core) {
866 abort(dump_core && CreateCoredumpOnCrash, NULL, NULL);
867 }
868
869 //---------------------------------------------------------------------------
870 // Helper functions for fatal error handler
871
872 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
873 assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
874
875 int cols = 0;
876 int cols_per_line = 0;
877 switch (unitsize) {
878 case 1: cols_per_line = 16; break;
879 case 2: cols_per_line = 8; break;
880 case 4: cols_per_line = 4; break;
881 case 8: cols_per_line = 2; break;
882 default: return;
883 }
884
885 address p = start;
886 st->print(PTR_FORMAT ": ", p2i(start));
887 while (p < end) {
888 switch (unitsize) {
889 case 1: st->print("%02x", *(u1*)p); break;
890 case 2: st->print("%04x", *(u2*)p); break;
891 case 4: st->print("%08x", *(u4*)p); break;
892 case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
893 }
894 p += unitsize;
895 cols++;
896 if (cols >= cols_per_line && p < end) {
897 cols = 0;
898 st->cr();
899 st->print(PTR_FORMAT ": ", p2i(p));
900 } else {
901 st->print(" ");
902 }
903 }
904 st->cr();
905 }
906
907 void os::print_environment_variables(outputStream* st, const char** env_list) {
908 if (env_list) {
909 st->print_cr("Environment Variables:");
910
911 for (int i = 0; env_list[i] != NULL; i++) {
912 char *envvar = ::getenv(env_list[i]);
913 if (envvar != NULL) {
914 st->print("%s", env_list[i]);
915 st->print("=");
916 st->print_cr("%s", envvar);
917 }
918 }
919 }
920 }
921
922 void os::print_cpu_info(outputStream* st, char* buf, size_t buflen) {
923 // cpu
924 st->print("CPU:");
925 st->print("total %d", os::processor_count());
926 // It's not safe to query number of active processors after crash
927 // st->print("(active %d)", os::active_processor_count()); but we can
928 // print the initial number of active processors.
929 // We access the raw value here because the assert in the accessor will
930 // fail if the crash occurs before initialization of this value.
931 st->print(" (initial active %d)", _initial_active_processor_count);
932 st->print(" %s", VM_Version::features_string());
933 st->cr();
934 pd_print_cpu_info(st, buf, buflen);
935 }
936
937 // Print a one line string summarizing the cpu, number of cores, memory, and operating system version
938 void os::print_summary_info(outputStream* st, char* buf, size_t buflen) {
939 st->print("Host: ");
940 #ifndef PRODUCT
941 if (get_host_name(buf, buflen)) {
942 st->print("%s, ", buf);
943 }
944 #endif // PRODUCT
945 get_summary_cpu_info(buf, buflen);
946 st->print("%s, ", buf);
947 size_t mem = physical_memory()/G;
948 if (mem == 0) { // for low memory systems
949 mem = physical_memory()/M;
950 st->print("%d cores, " SIZE_FORMAT "M, ", processor_count(), mem);
951 } else {
952 st->print("%d cores, " SIZE_FORMAT "G, ", processor_count(), mem);
953 }
954 get_summary_os_info(buf, buflen);
955 st->print_raw(buf);
956 st->cr();
957 }
958
959 void os::print_date_and_time(outputStream *st, char* buf, size_t buflen) {
960 const int secs_per_day = 86400;
961 const int secs_per_hour = 3600;
962 const int secs_per_min = 60;
963
964 time_t tloc;
965 (void)time(&tloc);
966 char* timestring = ctime(&tloc); // ctime adds newline.
967 // edit out the newline
968 char* nl = strchr(timestring, '\n');
969 if (nl != NULL) {
970 *nl = '\0';
971 }
972
973 struct tm tz;
974 if (localtime_pd(&tloc, &tz) != NULL) {
975 ::strftime(buf, buflen, "%Z", &tz);
976 st->print("Time: %s %s", timestring, buf);
977 } else {
978 st->print("Time: %s", timestring);
979 }
980
981 double t = os::elapsedTime();
982 // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
983 // Linux. Must be a bug in glibc ? Workaround is to round "t" to int
984 // before printf. We lost some precision, but who cares?
985 int eltime = (int)t; // elapsed time in seconds
986
987 // print elapsed time in a human-readable format:
988 int eldays = eltime / secs_per_day;
989 int day_secs = eldays * secs_per_day;
990 int elhours = (eltime - day_secs) / secs_per_hour;
991 int hour_secs = elhours * secs_per_hour;
992 int elmins = (eltime - day_secs - hour_secs) / secs_per_min;
993 int minute_secs = elmins * secs_per_min;
994 int elsecs = (eltime - day_secs - hour_secs - minute_secs);
995 st->print_cr(" elapsed time: %d seconds (%dd %dh %dm %ds)", eltime, eldays, elhours, elmins, elsecs);
996 }
997
998 // moved from debug.cpp (used to be find()) but still called from there
999 // The verbose parameter is only set by the debug code in one case
1000 void os::print_location(outputStream* st, intptr_t x, bool verbose) {
1001 address addr = (address)x;
1002 // Handle NULL first, so later checks don't need to protect against it.
1003 if (addr == NULL) {
1004 st->print_cr("0x0 is NULL");
1005 return;
1006 }
1007 CodeBlob* b = CodeCache::find_blob_unsafe(addr);
1008 if (b != NULL) {
1009 if (b->is_buffer_blob()) {
1010 // the interpreter is generated into a buffer blob
1011 InterpreterCodelet* i = Interpreter::codelet_containing(addr);
1012 if (i != NULL) {
1013 st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an Interpreter codelet", p2i(addr), (int)(addr - i->code_begin()));
1014 i->print_on(st);
1015 return;
1016 }
1017 if (Interpreter::contains(addr)) {
1018 st->print_cr(INTPTR_FORMAT " is pointing into interpreter code"
1019 " (not bytecode specific)", p2i(addr));
1020 return;
1021 }
1022 //
1023 if (AdapterHandlerLibrary::contains(b)) {
1024 st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an AdapterHandler", p2i(addr), (int)(addr - b->code_begin()));
1025 AdapterHandlerLibrary::print_handler_on(st, b);
1026 }
1027 // the stubroutines are generated into a buffer blob
1028 StubCodeDesc* d = StubCodeDesc::desc_for(addr);
1029 if (d != NULL) {
1030 st->print_cr(INTPTR_FORMAT " is at begin+%d in a stub", p2i(addr), (int)(addr - d->begin()));
1031 d->print_on(st);
1032 st->cr();
1033 return;
1034 }
1035 if (StubRoutines::contains(addr)) {
1036 st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) stub routine", p2i(addr));
1037 return;
1038 }
1039 // the InlineCacheBuffer is using stubs generated into a buffer blob
1040 if (InlineCacheBuffer::contains(addr)) {
1041 st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", p2i(addr));
1042 return;
1043 }
1044 VtableStub* v = VtableStubs::stub_containing(addr);
1045 if (v != NULL) {
1046 st->print_cr(INTPTR_FORMAT " is at entry_point+%d in a vtable stub", p2i(addr), (int)(addr - v->entry_point()));
1047 v->print_on(st);
1048 st->cr();
1049 return;
1050 }
1051 }
1052 nmethod* nm = b->as_nmethod_or_null();
1053 if (nm != NULL) {
1054 ResourceMark rm;
1055 st->print(INTPTR_FORMAT " is at entry_point+%d in (nmethod*)" INTPTR_FORMAT,
1056 p2i(addr), (int)(addr - nm->entry_point()), p2i(nm));
1057 if (verbose) {
1058 st->print(" for ");
1059 nm->method()->print_value_on(st);
1060 }
1061 st->cr();
1062 nm->print_nmethod(verbose);
1063 return;
1064 }
1065 st->print_cr(INTPTR_FORMAT " is at code_begin+%d in ", p2i(addr), (int)(addr - b->code_begin()));
1066 b->print_on(st);
1067 return;
1068 }
1069
1070 if (Universe::heap()->is_in(addr)) {
1071 HeapWord* p = Universe::heap()->block_start(addr);
1072 bool print = false;
1073 // If we couldn't find it it just may mean that heap wasn't parsable
1074 // See if we were just given an oop directly
1075 if (p != NULL && Universe::heap()->block_is_obj(p)) {
1076 print = true;
1077 } else if (p == NULL && oopDesc::is_oop(oop(addr))) {
1078 p = (HeapWord*) addr;
1079 print = true;
1080 }
1081 if (print) {
1082 if (p == (HeapWord*) addr) {
1083 st->print_cr(INTPTR_FORMAT " is an oop", p2i(addr));
1084 } else {
1085 st->print_cr(INTPTR_FORMAT " is pointing into object: " INTPTR_FORMAT, p2i(addr), p2i(p));
1086 }
1087 oop(p)->print_on(st);
1088 return;
1089 }
1090 } else {
1091 if (Universe::heap()->is_in_reserved(addr)) {
1092 st->print_cr(INTPTR_FORMAT " is an unallocated location "
1093 "in the heap", p2i(addr));
1094 return;
1095 }
1096 }
1097 if (JNIHandles::is_global_handle((jobject) addr)) {
1098 st->print_cr(INTPTR_FORMAT " is a global jni handle", p2i(addr));
1099 return;
1100 }
1101 if (JNIHandles::is_weak_global_handle((jobject) addr)) {
1102 st->print_cr(INTPTR_FORMAT " is a weak global jni handle", p2i(addr));
1103 return;
1104 }
1105 #ifndef PRODUCT
1106 // we don't keep the block list in product mode
1107 if (JNIHandles::is_local_handle((jobject) addr)) {
1108 st->print_cr(INTPTR_FORMAT " is a local jni handle", p2i(addr));
1109 return;
1110 }
1111 #endif
1112
1113 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
1114 // Check for privilege stack
1115 if (thread->privileged_stack_top() != NULL &&
1116 thread->privileged_stack_top()->contains(addr)) {
1117 st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack "
1118 "for thread: " INTPTR_FORMAT, p2i(addr), p2i(thread));
1119 if (verbose) thread->print_on(st);
1120 return;
1121 }
1122 // If the addr is a java thread print information about that.
1123 if (addr == (address)thread) {
1124 if (verbose) {
1125 thread->print_on(st);
1126 } else {
1127 st->print_cr(INTPTR_FORMAT " is a thread", p2i(addr));
1128 }
1129 return;
1130 }
1131 // If the addr is in the stack region for this thread then report that
1132 // and print thread info
1133 if (thread->on_local_stack(addr)) {
1134 st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
1135 INTPTR_FORMAT, p2i(addr), p2i(thread));
1136 if (verbose) thread->print_on(st);
1137 return;
1138 }
1139 }
1140
1141 // Check if in metaspace and print types that have vptrs (only method now)
1142 if (Metaspace::contains(addr)) {
1143 if (Method::has_method_vptr((const void*)addr)) {
1144 ((Method*)addr)->print_value_on(st);
1145 st->cr();
1146 } else {
1147 // Use addr->print() from the debugger instead (not here)
1148 st->print_cr(INTPTR_FORMAT " is pointing into metadata", p2i(addr));
1149 }
1150 return;
1151 }
1152
1153 // Try an OS specific find
1154 if (os::find(addr, st)) {
1155 return;
1156 }
1157
1158 st->print_cr(INTPTR_FORMAT " is an unknown value", p2i(addr));
1159 }
1160
1161 // Looks like all platforms except IA64 can use the same function to check
1162 // if C stack is walkable beyond current frame. The check for fp() is not
1163 // necessary on Sparc, but it's harmless.
1164 bool os::is_first_C_frame(frame* fr) {
1165 #if (defined(IA64) && !defined(AIX)) && !defined(_WIN32)
1166 // On IA64 we have to check if the callers bsp is still valid
1167 // (i.e. within the register stack bounds).
1168 // Notice: this only works for threads created by the VM and only if
1169 // we walk the current stack!!! If we want to be able to walk
1170 // arbitrary other threads, we'll have to somehow store the thread
1171 // object in the frame.
1172 Thread *thread = Thread::current();
1173 if ((address)fr->fp() <=
1174 thread->register_stack_base() HPUX_ONLY(+ 0x0) LINUX_ONLY(+ 0x50)) {
1175 // This check is a little hacky, because on Linux the first C
1176 // frame's ('start_thread') register stack frame starts at
1177 // "register_stack_base + 0x48" while on HPUX, the first C frame's
1178 // ('__pthread_bound_body') register stack frame seems to really
1179 // start at "register_stack_base".
1180 return true;
1181 } else {
1182 return false;
1183 }
1184 #elif defined(IA64) && defined(_WIN32)
1185 return true;
1186 #else
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 #endif
1217 }
1218
1219
1220 // Set up the boot classpath.
1221
1222 char* os::format_boot_path(const char* format_string,
1223 const char* home,
1224 int home_len,
1225 char fileSep,
1226 char pathSep) {
1227 assert((fileSep == '/' && pathSep == ':') ||
1228 (fileSep == '\\' && pathSep == ';'), "unexpected separator chars");
1229
1230 // Scan the format string to determine the length of the actual
1231 // boot classpath, and handle platform dependencies as well.
1232 int formatted_path_len = 0;
1233 const char* p;
1234 for (p = format_string; *p != 0; ++p) {
1235 if (*p == '%') formatted_path_len += home_len - 1;
1236 ++formatted_path_len;
1237 }
1238
1239 char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal);
1240 if (formatted_path == NULL) {
1241 return NULL;
1242 }
1243
1244 // Create boot classpath from format, substituting separator chars and
1245 // java home directory.
1246 char* q = formatted_path;
1247 for (p = format_string; *p != 0; ++p) {
1248 switch (*p) {
1249 case '%':
1250 strcpy(q, home);
1251 q += home_len;
1252 break;
1253 case '/':
1254 *q++ = fileSep;
1255 break;
1256 case ':':
1257 *q++ = pathSep;
1258 break;
1259 default:
1260 *q++ = *p;
1261 }
1262 }
1263 *q = '\0';
1264
1265 assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
1266 return formatted_path;
1267 }
1268
1269 bool os::set_boot_path(char fileSep, char pathSep) {
1270 const char* home = Arguments::get_java_home();
1271 int home_len = (int)strlen(home);
1272
1273 struct stat st;
1274
1275 // modular image if "modules" jimage exists
1276 char* jimage = format_boot_path("%/lib/" MODULES_IMAGE_NAME, home, home_len, fileSep, pathSep);
1277 if (jimage == NULL) return false;
1278 bool has_jimage = (os::stat(jimage, &st) == 0);
1279 if (has_jimage) {
1280 Arguments::set_sysclasspath(jimage, true);
1281 FREE_C_HEAP_ARRAY(char, jimage);
1282 return true;
1283 }
1284 FREE_C_HEAP_ARRAY(char, jimage);
1285
1286 // check if developer build with exploded modules
1287 char* base_classes = format_boot_path("%/modules/" JAVA_BASE_NAME, home, home_len, fileSep, pathSep);
1288 if (base_classes == NULL) return false;
1289 if (os::stat(base_classes, &st) == 0) {
1290 Arguments::set_sysclasspath(base_classes, false);
1291 FREE_C_HEAP_ARRAY(char, base_classes);
1292 return true;
1293 }
1294 FREE_C_HEAP_ARRAY(char, base_classes);
1295
1296 return false;
1297 }
1298
1299 /*
1300 * Splits a path, based on its separator, the number of
1301 * elements is returned back in n.
1302 * It is the callers responsibility to:
1303 * a> check the value of n, and n may be 0.
1304 * b> ignore any empty path elements
1305 * c> free up the data.
1306 */
1307 char** os::split_path(const char* path, int* n) {
1308 *n = 0;
1309 if (path == NULL || strlen(path) == 0) {
1310 return NULL;
1311 }
1312 const char psepchar = *os::path_separator();
1313 char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal);
1314 if (inpath == NULL) {
1315 return NULL;
1316 }
1317 strcpy(inpath, path);
1318 int count = 1;
1319 char* p = strchr(inpath, psepchar);
1320 // Get a count of elements to allocate memory
1321 while (p != NULL) {
1322 count++;
1323 p++;
1324 p = strchr(p, psepchar);
1325 }
1326 char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count, mtInternal);
1327 if (opath == NULL) {
1328 return NULL;
1329 }
1330
1331 // do the actual splitting
1332 p = inpath;
1333 for (int i = 0 ; i < count ; i++) {
1334 size_t len = strcspn(p, os::path_separator());
1335 if (len > JVM_MAXPATHLEN) {
1336 return NULL;
1337 }
1338 // allocate the string and add terminator storage
1339 char* s = (char*)NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
1340 if (s == NULL) {
1341 return NULL;
1342 }
1343 strncpy(s, p, len);
1344 s[len] = '\0';
1345 opath[i] = s;
1346 p += len + 1;
1347 }
1348 FREE_C_HEAP_ARRAY(char, inpath);
1349 *n = count;
1350 return opath;
1351 }
1352
1353 void os::set_memory_serialize_page(address page) {
1354 int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64);
1355 _mem_serialize_page = (volatile int32_t *)page;
1356 // We initialize the serialization page shift count here
1357 // We assume a cache line size of 64 bytes
1358 assert(SerializePageShiftCount == count, "JavaThread size changed; "
1359 "SerializePageShiftCount constant should be %d", count);
1360 set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t)));
1361 }
1362
1363 static volatile intptr_t SerializePageLock = 0;
1364
1365 // This method is called from signal handler when SIGSEGV occurs while the current
1366 // thread tries to store to the "read-only" memory serialize page during state
1367 // transition.
1368 void os::block_on_serialize_page_trap() {
1369 log_debug(safepoint)("Block until the serialize page permission restored");
1370
1371 // When VMThread is holding the SerializePageLock during modifying the
1372 // access permission of the memory serialize page, the following call
1373 // will block until the permission of that page is restored to rw.
1374 // Generally, it is unsafe to manipulate locks in signal handlers, but in
1375 // this case, it's OK as the signal is synchronous and we know precisely when
1376 // it can occur.
1377 Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page");
1378 Thread::muxRelease(&SerializePageLock);
1379 }
1380
1381 // Serialize all thread state variables
1382 void os::serialize_thread_states() {
1383 // On some platforms such as Solaris & Linux, the time duration of the page
1384 // permission restoration is observed to be much longer than expected due to
1385 // scheduler starvation problem etc. To avoid the long synchronization
1386 // time and expensive page trap spinning, 'SerializePageLock' is used to block
1387 // the mutator thread if such case is encountered. See bug 6546278 for details.
1388 Thread::muxAcquire(&SerializePageLock, "serialize_thread_states");
1389 os::protect_memory((char *)os::get_memory_serialize_page(),
1390 os::vm_page_size(), MEM_PROT_READ);
1391 os::protect_memory((char *)os::get_memory_serialize_page(),
1392 os::vm_page_size(), MEM_PROT_RW);
1393 Thread::muxRelease(&SerializePageLock);
1394 }
1395
1396 // Returns true if the current stack pointer is above the stack shadow
1397 // pages, false otherwise.
1398 bool os::stack_shadow_pages_available(Thread *thread, const methodHandle& method, address sp) {
1399 if (!thread->is_Java_thread()) return false;
1400 // Check if we have StackShadowPages above the yellow zone. This parameter
1401 // is dependent on the depth of the maximum VM call stack possible from
1402 // the handler for stack overflow. 'instanceof' in the stack overflow
1403 // handler or a println uses at least 8k stack of VM and native code
1404 // respectively.
1405 const int framesize_in_bytes =
1406 Interpreter::size_top_interpreter_activation(method()) * wordSize;
1407
1408 address limit = ((JavaThread*)thread)->stack_end() +
1409 (JavaThread::stack_guard_zone_size() + JavaThread::stack_shadow_zone_size());
1410
1411 return sp > (limit + framesize_in_bytes);
1412 }
1413
1414 size_t os::page_size_for_region(size_t region_size, size_t min_pages, bool must_be_aligned) {
1415 assert(min_pages > 0, "sanity");
1416 if (UseLargePages) {
1417 const size_t max_page_size = region_size / min_pages;
1418
1419 for (size_t i = 0; _page_sizes[i] != 0; ++i) {
1420 const size_t page_size = _page_sizes[i];
1421 if (page_size <= max_page_size) {
1422 if (!must_be_aligned || is_aligned(region_size, page_size)) {
1423 return page_size;
1424 }
1425 }
1426 }
1427 }
1428
1429 return vm_page_size();
1430 }
1431
1432 size_t os::page_size_for_region_aligned(size_t region_size, size_t min_pages) {
1433 return page_size_for_region(region_size, min_pages, true);
1434 }
1435
1436 size_t os::page_size_for_region_unaligned(size_t region_size, size_t min_pages) {
1437 return page_size_for_region(region_size, min_pages, false);
1438 }
1439
1440 static const char* errno_to_string (int e, bool short_text) {
1441 #define ALL_SHARED_ENUMS(X) \
1442 X(E2BIG, "Argument list too long") \
1443 X(EACCES, "Permission denied") \
1444 X(EADDRINUSE, "Address in use") \
1445 X(EADDRNOTAVAIL, "Address not available") \
1446 X(EAFNOSUPPORT, "Address family not supported") \
1447 X(EAGAIN, "Resource unavailable, try again") \
1448 X(EALREADY, "Connection already in progress") \
1449 X(EBADF, "Bad file descriptor") \
1450 X(EBADMSG, "Bad message") \
1451 X(EBUSY, "Device or resource busy") \
1452 X(ECANCELED, "Operation canceled") \
1453 X(ECHILD, "No child processes") \
1454 X(ECONNABORTED, "Connection aborted") \
1455 X(ECONNREFUSED, "Connection refused") \
1456 X(ECONNRESET, "Connection reset") \
1457 X(EDEADLK, "Resource deadlock would occur") \
1458 X(EDESTADDRREQ, "Destination address required") \
1459 X(EDOM, "Mathematics argument out of domain of function") \
1460 X(EEXIST, "File exists") \
1461 X(EFAULT, "Bad address") \
1462 X(EFBIG, "File too large") \
1463 X(EHOSTUNREACH, "Host is unreachable") \
1464 X(EIDRM, "Identifier removed") \
1465 X(EILSEQ, "Illegal byte sequence") \
1466 X(EINPROGRESS, "Operation in progress") \
1467 X(EINTR, "Interrupted function") \
1468 X(EINVAL, "Invalid argument") \
1469 X(EIO, "I/O error") \
1470 X(EISCONN, "Socket is connected") \
1471 X(EISDIR, "Is a directory") \
1472 X(ELOOP, "Too many levels of symbolic links") \
1473 X(EMFILE, "Too many open files") \
1474 X(EMLINK, "Too many links") \
1475 X(EMSGSIZE, "Message too large") \
1476 X(ENAMETOOLONG, "Filename too long") \
1477 X(ENETDOWN, "Network is down") \
1478 X(ENETRESET, "Connection aborted by network") \
1479 X(ENETUNREACH, "Network unreachable") \
1480 X(ENFILE, "Too many files open in system") \
1481 X(ENOBUFS, "No buffer space available") \
1482 X(ENODATA, "No message is available on the STREAM head read queue") \
1483 X(ENODEV, "No such device") \
1484 X(ENOENT, "No such file or directory") \
1485 X(ENOEXEC, "Executable file format error") \
1486 X(ENOLCK, "No locks available") \
1487 X(ENOLINK, "Reserved") \
1488 X(ENOMEM, "Not enough space") \
1489 X(ENOMSG, "No message of the desired type") \
1490 X(ENOPROTOOPT, "Protocol not available") \
1491 X(ENOSPC, "No space left on device") \
1492 X(ENOSR, "No STREAM resources") \
1493 X(ENOSTR, "Not a STREAM") \
1494 X(ENOSYS, "Function not supported") \
1495 X(ENOTCONN, "The socket is not connected") \
1496 X(ENOTDIR, "Not a directory") \
1497 X(ENOTEMPTY, "Directory not empty") \
1498 X(ENOTSOCK, "Not a socket") \
1499 X(ENOTSUP, "Not supported") \
1500 X(ENOTTY, "Inappropriate I/O control operation") \
1501 X(ENXIO, "No such device or address") \
1502 X(EOPNOTSUPP, "Operation not supported on socket") \
1503 X(EOVERFLOW, "Value too large to be stored in data type") \
1504 X(EPERM, "Operation not permitted") \
1505 X(EPIPE, "Broken pipe") \
1506 X(EPROTO, "Protocol error") \
1507 X(EPROTONOSUPPORT, "Protocol not supported") \
1508 X(EPROTOTYPE, "Protocol wrong type for socket") \
1509 X(ERANGE, "Result too large") \
1510 X(EROFS, "Read-only file system") \
1511 X(ESPIPE, "Invalid seek") \
1512 X(ESRCH, "No such process") \
1513 X(ETIME, "Stream ioctl() timeout") \
1514 X(ETIMEDOUT, "Connection timed out") \
1515 X(ETXTBSY, "Text file busy") \
1516 X(EWOULDBLOCK, "Operation would block") \
1517 X(EXDEV, "Cross-device link")
1518
1519 #define DEFINE_ENTRY(e, text) { e, #e, text },
1520
1521 static const struct {
1522 int v;
1523 const char* short_text;
1524 const char* long_text;
1525 } table [] = {
1526
1527 ALL_SHARED_ENUMS(DEFINE_ENTRY)
1528
1529 // The following enums are not defined on all platforms.
1530 #ifdef ESTALE
1531 DEFINE_ENTRY(ESTALE, "Reserved")
1532 #endif
1533 #ifdef EDQUOT
1534 DEFINE_ENTRY(EDQUOT, "Reserved")
1535 #endif
1536 #ifdef EMULTIHOP
1537 DEFINE_ENTRY(EMULTIHOP, "Reserved")
1538 #endif
1539
1540 // End marker.
1541 { -1, "Unknown errno", "Unknown error" }
1542
1543 };
1544
1545 #undef DEFINE_ENTRY
1546 #undef ALL_FLAGS
1547
1548 int i = 0;
1549 while (table[i].v != -1 && table[i].v != e) {
1550 i ++;
1551 }
1552
1553 return short_text ? table[i].short_text : table[i].long_text;
1554
1555 }
1556
1557 const char* os::strerror(int e) {
1558 return errno_to_string(e, false);
1559 }
1560
1561 const char* os::errno_name(int e) {
1562 return errno_to_string(e, true);
1563 }
1564
1565 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count) {
1566 LogTarget(Info, pagesize) log;
1567 if (log.is_enabled()) {
1568 LogStream out(log);
1569
1570 out.print("%s: ", str);
1571 for (int i = 0; i < count; ++i) {
1572 out.print(" " SIZE_FORMAT, page_sizes[i]);
1573 }
1574 out.cr();
1575 }
1576 }
1577
1578 #define trace_page_size_params(size) byte_size_in_exact_unit(size), exact_unit_for_byte_size(size)
1579
1580 void os::trace_page_sizes(const char* str,
1581 const size_t region_min_size,
1582 const size_t region_max_size,
1583 const size_t page_size,
1584 const char* base,
1585 const size_t size) {
1586
1587 log_info(pagesize)("%s: "
1588 " min=" SIZE_FORMAT "%s"
1589 " max=" SIZE_FORMAT "%s"
1590 " base=" PTR_FORMAT
1591 " page_size=" SIZE_FORMAT "%s"
1592 " size=" SIZE_FORMAT "%s",
1593 str,
1594 trace_page_size_params(region_min_size),
1595 trace_page_size_params(region_max_size),
1596 p2i(base),
1597 trace_page_size_params(page_size),
1598 trace_page_size_params(size));
1599 }
1600
1601 void os::trace_page_sizes_for_requested_size(const char* str,
1602 const size_t requested_size,
1603 const size_t page_size,
1604 const size_t alignment,
1605 const char* base,
1606 const size_t size) {
1607
1608 log_info(pagesize)("%s:"
1609 " req_size=" SIZE_FORMAT "%s"
1610 " base=" PTR_FORMAT
1611 " page_size=" SIZE_FORMAT "%s"
1612 " alignment=" SIZE_FORMAT "%s"
1613 " size=" SIZE_FORMAT "%s",
1614 str,
1615 trace_page_size_params(requested_size),
1616 p2i(base),
1617 trace_page_size_params(page_size),
1618 trace_page_size_params(alignment),
1619 trace_page_size_params(size));
1620 }
1621
1622
1623 // This is the working definition of a server class machine:
1624 // >= 2 physical CPU's and >=2GB of memory, with some fuzz
1625 // because the graphics memory (?) sometimes masks physical memory.
1626 // If you want to change the definition of a server class machine
1627 // on some OS or platform, e.g., >=4GB on Windows platforms,
1628 // then you'll have to parameterize this method based on that state,
1629 // as was done for logical processors here, or replicate and
1630 // specialize this method for each platform. (Or fix os to have
1631 // some inheritance structure and use subclassing. Sigh.)
1632 // If you want some platform to always or never behave as a server
1633 // class machine, change the setting of AlwaysActAsServerClassMachine
1634 // and NeverActAsServerClassMachine in globals*.hpp.
1635 bool os::is_server_class_machine() {
1636 // First check for the early returns
1637 if (NeverActAsServerClassMachine) {
1638 return false;
1639 }
1640 if (AlwaysActAsServerClassMachine) {
1641 return true;
1642 }
1643 // Then actually look at the machine
1644 bool result = false;
1645 const unsigned int server_processors = 2;
1646 const julong server_memory = 2UL * G;
1647 // We seem not to get our full complement of memory.
1648 // We allow some part (1/8?) of the memory to be "missing",
1649 // based on the sizes of DIMMs, and maybe graphics cards.
1650 const julong missing_memory = 256UL * M;
1651
1652 /* Is this a server class machine? */
1653 if ((os::active_processor_count() >= (int)server_processors) &&
1654 (os::physical_memory() >= (server_memory - missing_memory))) {
1655 const unsigned int logical_processors =
1656 VM_Version::logical_processors_per_package();
1657 if (logical_processors > 1) {
1658 const unsigned int physical_packages =
1659 os::active_processor_count() / logical_processors;
1660 if (physical_packages >= server_processors) {
1661 result = true;
1662 }
1663 } else {
1664 result = true;
1665 }
1666 }
1667 return result;
1668 }
1669
1670 void os::initialize_initial_active_processor_count() {
1671 assert(_initial_active_processor_count == 0, "Initial active processor count already set.");
1672 _initial_active_processor_count = active_processor_count();
1673 log_debug(os)("Initial active processor count set to %d" , _initial_active_processor_count);
1674 }
1675
1676 void os::SuspendedThreadTask::run() {
1677 internal_do_task();
1678 _done = true;
1679 }
1680
1681 bool os::create_stack_guard_pages(char* addr, size_t bytes) {
1682 return os::pd_create_stack_guard_pages(addr, bytes);
1683 }
1684
1685 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint, int file_desc) {
1686 char* result = NULL;
1687
1688 if (file_desc != -1) {
1689 // Could have called pd_reserve_memory() followed by replace_existing_mapping_with_file_mapping(),
1690 // but AIX may use SHM in which case its more trouble to detach the segment and remap memory to the file.
1691 result = os::map_memory_to_file(addr, bytes, file_desc);
1692 if (result != NULL) {
1693 MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1694 }
1695 } else {
1696 result = pd_reserve_memory(bytes, addr, alignment_hint);
1697 if (result != NULL) {
1698 MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1699 }
1700 }
1701
1702 return result;
1703 }
1704
1705 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint,
1706 MEMFLAGS flags) {
1707 char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1708 if (result != NULL) {
1709 MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1710 MemTracker::record_virtual_memory_type((address)result, flags);
1711 }
1712
1713 return result;
1714 }
1715
1716 char* os::attempt_reserve_memory_at(size_t bytes, char* addr, int file_desc) {
1717 char* result = NULL;
1718 if (file_desc != -1) {
1719 result = pd_attempt_reserve_memory_at(bytes, addr, file_desc);
1720 if (result != NULL) {
1721 MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1722 }
1723 } else {
1724 result = pd_attempt_reserve_memory_at(bytes, addr);
1725 if (result != NULL) {
1726 MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1727 }
1728 }
1729 return result;
1730 }
1731
1732 void os::split_reserved_memory(char *base, size_t size,
1733 size_t split, bool realloc) {
1734 pd_split_reserved_memory(base, size, split, realloc);
1735 }
1736
1737 bool os::commit_memory(char* addr, size_t bytes, bool executable) {
1738 bool res = pd_commit_memory(addr, bytes, executable);
1739 if (res) {
1740 MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1741 }
1742 return res;
1743 }
1744
1745 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
1746 bool executable) {
1747 bool res = os::pd_commit_memory(addr, size, alignment_hint, executable);
1748 if (res) {
1749 MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1750 }
1751 return res;
1752 }
1753
1754 void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable,
1755 const char* mesg) {
1756 pd_commit_memory_or_exit(addr, bytes, executable, mesg);
1757 MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1758 }
1759
1760 void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint,
1761 bool executable, const char* mesg) {
1762 os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg);
1763 MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1764 }
1765
1766 bool os::uncommit_memory(char* addr, size_t bytes) {
1767 bool res;
1768 if (MemTracker::tracking_level() > NMT_minimal) {
1769 Tracker tkr(Tracker::uncommit);
1770 res = pd_uncommit_memory(addr, bytes);
1771 if (res) {
1772 tkr.record((address)addr, bytes);
1773 }
1774 } else {
1775 res = pd_uncommit_memory(addr, bytes);
1776 }
1777 return res;
1778 }
1779
1780 bool os::release_memory(char* addr, size_t bytes) {
1781 bool res;
1782 if (MemTracker::tracking_level() > NMT_minimal) {
1783 Tracker tkr(Tracker::release);
1784 res = pd_release_memory(addr, bytes);
1785 if (res) {
1786 tkr.record((address)addr, bytes);
1787 }
1788 } else {
1789 res = pd_release_memory(addr, bytes);
1790 }
1791 return res;
1792 }
1793
1794 void os::pretouch_memory(void* start, void* end, size_t page_size) {
1795 for (volatile char *p = (char*)start; p < (char*)end; p += page_size) {
1796 *p = 0;
1797 }
1798 }
1799
1800 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
1801 char *addr, size_t bytes, bool read_only,
1802 bool allow_exec) {
1803 char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec);
1804 if (result != NULL) {
1805 MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1806 }
1807 return result;
1808 }
1809
1810 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
1811 char *addr, size_t bytes, bool read_only,
1812 bool allow_exec) {
1813 return pd_remap_memory(fd, file_name, file_offset, addr, bytes,
1814 read_only, allow_exec);
1815 }
1816
1817 bool os::unmap_memory(char *addr, size_t bytes) {
1818 bool result;
1819 if (MemTracker::tracking_level() > NMT_minimal) {
1820 Tracker tkr(Tracker::release);
1821 result = pd_unmap_memory(addr, bytes);
1822 if (result) {
1823 tkr.record((address)addr, bytes);
1824 }
1825 } else {
1826 result = pd_unmap_memory(addr, bytes);
1827 }
1828 return result;
1829 }
1830
1831 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
1832 pd_free_memory(addr, bytes, alignment_hint);
1833 }
1834
1835 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
1836 pd_realign_memory(addr, bytes, alignment_hint);
1837 }
1838
1839 #ifndef _WINDOWS
1840 /* try to switch state from state "from" to state "to"
1841 * returns the state set after the method is complete
1842 */
1843 os::SuspendResume::State os::SuspendResume::switch_state(os::SuspendResume::State from,
1844 os::SuspendResume::State to)
1845 {
1846 os::SuspendResume::State result = Atomic::cmpxchg(to, &_state, from);
1847 if (result == from) {
1848 // success
1849 return to;
1850 }
1851 return result;
1852 }
1853 #endif