/
os.cpp
1951 lines (1715 loc) · 65.4 KB
/
os.cpp
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/*
* Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "jvm.h"
#include "classfile/javaClasses.hpp"
#include "classfile/moduleEntry.hpp"
#include "classfile/systemDictionary.hpp"
#include "classfile/vmClasses.hpp"
#include "classfile/vmSymbols.hpp"
#include "code/codeCache.hpp"
#include "code/icBuffer.hpp"
#include "code/vtableStubs.hpp"
#include "gc/shared/gcVMOperations.hpp"
#include "logging/log.hpp"
#include "interpreter/interpreter.hpp"
#include "logging/log.hpp"
#include "logging/logStream.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/resourceArea.hpp"
#include "memory/universe.hpp"
#include "oops/compressedOops.inline.hpp"
#include "oops/oop.inline.hpp"
#include "prims/jvm_misc.hpp"
#include "runtime/arguments.hpp"
#include "runtime/atomic.hpp"
#include "runtime/frame.inline.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/interfaceSupport.inline.hpp"
#include "runtime/java.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/jniHandles.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/os.inline.hpp"
#include "runtime/osThread.hpp"
#include "runtime/safefetch.inline.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/thread.inline.hpp"
#include "runtime/threadSMR.hpp"
#include "runtime/vmOperations.hpp"
#include "runtime/vm_version.hpp"
#include "services/attachListener.hpp"
#include "services/mallocTracker.hpp"
#include "services/memTracker.hpp"
#include "services/nmtPreInit.hpp"
#include "services/nmtCommon.hpp"
#include "services/threadService.hpp"
#include "utilities/align.hpp"
#include "utilities/count_trailing_zeros.hpp"
#include "utilities/defaultStream.hpp"
#include "utilities/events.hpp"
#include "utilities/powerOfTwo.hpp"
# include <signal.h>
# include <errno.h>
OSThread* os::_starting_thread = NULL;
address os::_polling_page = NULL;
volatile unsigned int os::_rand_seed = 1234567;
int os::_processor_count = 0;
int os::_initial_active_processor_count = 0;
os::PageSizes os::_page_sizes;
static size_t cur_malloc_words = 0; // current size for MallocMaxTestWords
DEBUG_ONLY(bool os::_mutex_init_done = false;)
int os::snprintf(char* buf, size_t len, const char* fmt, ...) {
va_list args;
va_start(args, fmt);
int result = os::vsnprintf(buf, len, fmt, args);
va_end(args);
return result;
}
// Fill in buffer with current local time as an ISO-8601 string.
// E.g., YYYY-MM-DDThh:mm:ss.mmm+zzzz.
// Returns buffer, or NULL if it failed.
char* os::iso8601_time(char* buffer, size_t buffer_length, bool utc) {
const jlong now = javaTimeMillis();
return os::iso8601_time(now, buffer, buffer_length, utc);
}
// Fill in buffer with an ISO-8601 string corresponding to the given javaTimeMillis value
// E.g., yyyy-mm-ddThh:mm:ss-zzzz.
// Returns buffer, or NULL if it failed.
// This would mostly be a call to
// strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
// except that on Windows the %z behaves badly, so we do it ourselves.
// Also, people wanted milliseconds on there,
// and strftime doesn't do milliseconds.
char* os::iso8601_time(jlong milliseconds_since_19700101, char* buffer, size_t buffer_length, bool utc) {
// Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
// Sanity check the arguments
if (buffer == NULL) {
assert(false, "NULL buffer");
return NULL;
}
if (buffer_length < os::iso8601_timestamp_size) {
assert(false, "buffer_length too small");
return NULL;
}
const int milliseconds_per_microsecond = 1000;
const time_t seconds_since_19700101 =
milliseconds_since_19700101 / milliseconds_per_microsecond;
const int milliseconds_after_second =
milliseconds_since_19700101 % milliseconds_per_microsecond;
// Convert the time value to a tm and timezone variable
struct tm time_struct;
if (utc) {
if (gmtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
assert(false, "Failed gmtime_pd");
return NULL;
}
} else {
if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
assert(false, "Failed localtime_pd");
return NULL;
}
}
const time_t seconds_per_minute = 60;
const time_t minutes_per_hour = 60;
const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
// No offset when dealing with UTC
time_t UTC_to_local = 0;
if (!utc) {
#if defined(_ALLBSD_SOURCE) || defined(_GNU_SOURCE)
UTC_to_local = -(time_struct.tm_gmtoff);
#elif defined(_WINDOWS)
long zone;
_get_timezone(&zone);
UTC_to_local = static_cast<time_t>(zone);
#else
UTC_to_local = timezone;
#endif
// tm_gmtoff already includes adjustment for daylight saving
#if !defined(_ALLBSD_SOURCE) && !defined(_GNU_SOURCE)
// If daylight savings time is in effect,
// we are 1 hour East of our time zone
if (time_struct.tm_isdst > 0) {
UTC_to_local = UTC_to_local - seconds_per_hour;
}
#endif
}
// Compute the time zone offset.
// localtime_pd() sets timezone to the difference (in seconds)
// between UTC and and local time.
// ISO 8601 says we need the difference between local time and UTC,
// we change the sign of the localtime_pd() result.
const time_t local_to_UTC = -(UTC_to_local);
// Then we have to figure out if if we are ahead (+) or behind (-) UTC.
char sign_local_to_UTC = '+';
time_t abs_local_to_UTC = local_to_UTC;
if (local_to_UTC < 0) {
sign_local_to_UTC = '-';
abs_local_to_UTC = -(abs_local_to_UTC);
}
// Convert time zone offset seconds to hours and minutes.
const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
const time_t zone_min =
((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
// Print an ISO 8601 date and time stamp into the buffer
const int year = 1900 + time_struct.tm_year;
const int month = 1 + time_struct.tm_mon;
const int printed = jio_snprintf(buffer, buffer_length,
"%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d",
year,
month,
time_struct.tm_mday,
time_struct.tm_hour,
time_struct.tm_min,
time_struct.tm_sec,
milliseconds_after_second,
sign_local_to_UTC,
zone_hours,
zone_min);
if (printed == 0) {
assert(false, "Failed jio_printf");
return NULL;
}
return buffer;
}
OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
debug_only(Thread::check_for_dangling_thread_pointer(thread);)
if ((p >= MinPriority && p <= MaxPriority) ||
(p == CriticalPriority && thread->is_ConcurrentGC_thread())) {
int priority = java_to_os_priority[p];
return set_native_priority(thread, priority);
} else {
assert(false, "Should not happen");
return OS_ERR;
}
}
// The mapping from OS priority back to Java priority may be inexact because
// Java priorities can map M:1 with native priorities. If you want the definite
// Java priority then use JavaThread::java_priority()
OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
int p;
int os_prio;
OSReturn ret = get_native_priority(thread, &os_prio);
if (ret != OS_OK) return ret;
if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) {
for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
} else {
// niceness values are in reverse order
for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] < os_prio; p--) ;
}
priority = (ThreadPriority)p;
return OS_OK;
}
bool os::dll_build_name(char* buffer, size_t size, const char* fname) {
int n = jio_snprintf(buffer, size, "%s%s%s", JNI_LIB_PREFIX, fname, JNI_LIB_SUFFIX);
return (n != -1);
}
#if !defined(LINUX) && !defined(_WINDOWS)
bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
committed_start = start;
committed_size = size;
return true;
}
#endif
// Helper for dll_locate_lib.
// Pass buffer and printbuffer as we already printed the path to buffer
// when we called get_current_directory. This way we avoid another buffer
// of size MAX_PATH.
static bool conc_path_file_and_check(char *buffer, char *printbuffer, size_t printbuflen,
const char* pname, char lastchar, const char* fname) {
// Concatenate path and file name, but don't print double path separators.
const char *filesep = (WINDOWS_ONLY(lastchar == ':' ||) lastchar == os::file_separator()[0]) ?
"" : os::file_separator();
int ret = jio_snprintf(printbuffer, printbuflen, "%s%s%s", pname, filesep, fname);
// Check whether file exists.
if (ret != -1) {
struct stat statbuf;
return os::stat(buffer, &statbuf) == 0;
}
return false;
}
// Frees all memory allocated on the heap for the
// supplied array of arrays of chars (a), where n
// is the number of elements in the array.
static void free_array_of_char_arrays(char** a, size_t n) {
while (n > 0) {
n--;
if (a[n] != NULL) {
FREE_C_HEAP_ARRAY(char, a[n]);
}
}
FREE_C_HEAP_ARRAY(char*, a);
}
bool os::dll_locate_lib(char *buffer, size_t buflen,
const char* pname, const char* fname) {
bool retval = false;
size_t fullfnamelen = strlen(JNI_LIB_PREFIX) + strlen(fname) + strlen(JNI_LIB_SUFFIX);
char* fullfname = NEW_C_HEAP_ARRAY(char, fullfnamelen + 1, mtInternal);
if (dll_build_name(fullfname, fullfnamelen + 1, fname)) {
const size_t pnamelen = pname ? strlen(pname) : 0;
if (pnamelen == 0) {
// If no path given, use current working directory.
const char* p = get_current_directory(buffer, buflen);
if (p != NULL) {
const size_t plen = strlen(buffer);
const char lastchar = buffer[plen - 1];
retval = conc_path_file_and_check(buffer, &buffer[plen], buflen - plen,
"", lastchar, fullfname);
}
} else if (strchr(pname, *os::path_separator()) != NULL) {
// A list of paths. Search for the path that contains the library.
size_t n;
char** pelements = split_path(pname, &n, fullfnamelen);
if (pelements != NULL) {
for (size_t i = 0; i < n; i++) {
char* path = pelements[i];
// Really shouldn't be NULL, but check can't hurt.
size_t plen = (path == NULL) ? 0 : strlen(path);
if (plen == 0) {
continue; // Skip the empty path values.
}
const char lastchar = path[plen - 1];
retval = conc_path_file_and_check(buffer, buffer, buflen, path, lastchar, fullfname);
if (retval) break;
}
// Release the storage allocated by split_path.
free_array_of_char_arrays(pelements, n);
}
} else {
// A definite path.
const char lastchar = pname[pnamelen-1];
retval = conc_path_file_and_check(buffer, buffer, buflen, pname, lastchar, fullfname);
}
}
FREE_C_HEAP_ARRAY(char*, fullfname);
return retval;
}
// --------------------- sun.misc.Signal (optional) ---------------------
// SIGBREAK is sent by the keyboard to query the VM state
#ifndef SIGBREAK
#define SIGBREAK SIGQUIT
#endif
// sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
static void signal_thread_entry(JavaThread* thread, TRAPS) {
os::set_priority(thread, NearMaxPriority);
while (true) {
int sig;
{
// FIXME : Currently we have not decided what should be the status
// for this java thread blocked here. Once we decide about
// that we should fix this.
sig = os::signal_wait();
}
if (sig == os::sigexitnum_pd()) {
// Terminate the signal thread
return;
}
switch (sig) {
case SIGBREAK: {
#if INCLUDE_SERVICES
// Check if the signal is a trigger to start the Attach Listener - in that
// case don't print stack traces.
if (!DisableAttachMechanism) {
// Attempt to transit state to AL_INITIALIZING.
AttachListenerState cur_state = AttachListener::transit_state(AL_INITIALIZING, AL_NOT_INITIALIZED);
if (cur_state == AL_INITIALIZING) {
// Attach Listener has been started to initialize. Ignore this signal.
continue;
} else if (cur_state == AL_NOT_INITIALIZED) {
// Start to initialize.
if (AttachListener::is_init_trigger()) {
// Attach Listener has been initialized.
// Accept subsequent request.
continue;
} else {
// Attach Listener could not be started.
// So we need to transit the state to AL_NOT_INITIALIZED.
AttachListener::set_state(AL_NOT_INITIALIZED);
}
} else if (AttachListener::check_socket_file()) {
// Attach Listener has been started, but unix domain socket file
// does not exist. So restart Attach Listener.
continue;
}
}
#endif
// Print stack traces
// Any SIGBREAK operations added here should make sure to flush
// the output stream (e.g. tty->flush()) after output. See 4803766.
// Each module also prints an extra carriage return after its output.
VM_PrintThreads op(tty, PrintConcurrentLocks, false /* no extended info */, true /* print JNI handle info */);
VMThread::execute(&op);
VM_FindDeadlocks op1(tty);
VMThread::execute(&op1);
Universe::print_heap_at_SIGBREAK();
if (PrintClassHistogram) {
VM_GC_HeapInspection op1(tty, true /* force full GC before heap inspection */);
VMThread::execute(&op1);
}
if (JvmtiExport::should_post_data_dump()) {
JvmtiExport::post_data_dump();
}
break;
}
default: {
// Dispatch the signal to java
HandleMark hm(THREAD);
Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_misc_Signal(), THREAD);
if (klass != NULL) {
JavaValue result(T_VOID);
JavaCallArguments args;
args.push_int(sig);
JavaCalls::call_static(
&result,
klass,
vmSymbols::dispatch_name(),
vmSymbols::int_void_signature(),
&args,
THREAD
);
}
if (HAS_PENDING_EXCEPTION) {
// tty is initialized early so we don't expect it to be null, but
// if it is we can't risk doing an initialization that might
// trigger additional out-of-memory conditions
if (tty != NULL) {
char klass_name[256];
char tmp_sig_name[16];
const char* sig_name = "UNKNOWN";
InstanceKlass::cast(PENDING_EXCEPTION->klass())->
name()->as_klass_external_name(klass_name, 256);
if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
sig_name = tmp_sig_name;
warning("Exception %s occurred dispatching signal %s to handler"
"- the VM may need to be forcibly terminated",
klass_name, sig_name );
}
CLEAR_PENDING_EXCEPTION;
}
}
}
}
}
void os::init_before_ergo() {
initialize_initial_active_processor_count();
// We need to initialize large page support here because ergonomics takes some
// decisions depending on large page support and the calculated large page size.
large_page_init();
StackOverflow::initialize_stack_zone_sizes();
// VM version initialization identifies some characteristics of the
// platform that are used during ergonomic decisions.
VM_Version::init_before_ergo();
}
void os::initialize_jdk_signal_support(TRAPS) {
if (!ReduceSignalUsage) {
// Setup JavaThread for processing signals
const char* name = "Signal Dispatcher";
Handle thread_oop = JavaThread::create_system_thread_object(name, true /* visible */, CHECK);
JavaThread* thread = new JavaThread(&signal_thread_entry);
JavaThread::vm_exit_on_osthread_failure(thread);
JavaThread::start_internal_daemon(THREAD, thread, thread_oop, NearMaxPriority);
// Handle ^BREAK
os::signal(SIGBREAK, os::user_handler());
}
}
void os::terminate_signal_thread() {
if (!ReduceSignalUsage)
signal_notify(sigexitnum_pd());
}
// --------------------- loading libraries ---------------------
typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
extern struct JavaVM_ main_vm;
static void* _native_java_library = NULL;
void* os::native_java_library() {
if (_native_java_library == NULL) {
char buffer[JVM_MAXPATHLEN];
char ebuf[1024];
// Load java dll
if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
"java")) {
_native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
}
if (_native_java_library == NULL) {
vm_exit_during_initialization("Unable to load native library", ebuf);
}
#if defined(__OpenBSD__)
// Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so
// ignore errors
if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
"net")) {
dll_load(buffer, ebuf, sizeof(ebuf));
}
#endif
}
return _native_java_library;
}
/*
* Support for finding Agent_On(Un)Load/Attach<_lib_name> if it exists.
* If check_lib == true then we are looking for an
* Agent_OnLoad_lib_name or Agent_OnAttach_lib_name function to determine if
* this library is statically linked into the image.
* If check_lib == false then we will look for the appropriate symbol in the
* executable if agent_lib->is_static_lib() == true or in the shared library
* referenced by 'handle'.
*/
void* os::find_agent_function(AgentLibrary *agent_lib, bool check_lib,
const char *syms[], size_t syms_len) {
assert(agent_lib != NULL, "sanity check");
const char *lib_name;
void *handle = agent_lib->os_lib();
void *entryName = NULL;
char *agent_function_name;
size_t i;
// If checking then use the agent name otherwise test is_static_lib() to
// see how to process this lookup
lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : NULL);
for (i = 0; i < syms_len; i++) {
agent_function_name = build_agent_function_name(syms[i], lib_name, agent_lib->is_absolute_path());
if (agent_function_name == NULL) {
break;
}
entryName = dll_lookup(handle, agent_function_name);
FREE_C_HEAP_ARRAY(char, agent_function_name);
if (entryName != NULL) {
break;
}
}
return entryName;
}
// See if the passed in agent is statically linked into the VM image.
bool os::find_builtin_agent(AgentLibrary *agent_lib, const char *syms[],
size_t syms_len) {
void *ret;
void *proc_handle;
void *save_handle;
assert(agent_lib != NULL, "sanity check");
if (agent_lib->name() == NULL) {
return false;
}
proc_handle = get_default_process_handle();
// Check for Agent_OnLoad/Attach_lib_name function
save_handle = agent_lib->os_lib();
// We want to look in this process' symbol table.
agent_lib->set_os_lib(proc_handle);
ret = find_agent_function(agent_lib, true, syms, syms_len);
if (ret != NULL) {
// Found an entry point like Agent_OnLoad_lib_name so we have a static agent
agent_lib->set_valid();
agent_lib->set_static_lib(true);
return true;
}
agent_lib->set_os_lib(save_handle);
return false;
}
// --------------------- heap allocation utilities ---------------------
char *os::strdup(const char *str, MEMFLAGS flags) {
size_t size = strlen(str);
char *dup_str = (char *)malloc(size + 1, flags);
if (dup_str == NULL) return NULL;
strcpy(dup_str, str);
return dup_str;
}
char* os::strdup_check_oom(const char* str, MEMFLAGS flags) {
char* p = os::strdup(str, flags);
if (p == NULL) {
vm_exit_out_of_memory(strlen(str) + 1, OOM_MALLOC_ERROR, "os::strdup_check_oom");
}
return p;
}
//
// This function supports testing of the malloc out of memory
// condition without really running the system out of memory.
//
static bool has_reached_max_malloc_test_peak(size_t alloc_size) {
if (MallocMaxTestWords > 0) {
size_t words = (alloc_size / BytesPerWord);
if ((cur_malloc_words + words) > MallocMaxTestWords) {
return true;
}
Atomic::add(&cur_malloc_words, words);
}
return false;
}
#ifdef ASSERT
static void check_crash_protection() {
assert(!os::ThreadCrashProtection::is_crash_protected(Thread::current_or_null()),
"not allowed when crash protection is set");
}
static void break_if_ptr_caught(void* ptr) {
if (p2i(ptr) == (intptr_t)MallocCatchPtr) {
log_warning(malloc, free)("ptr caught: " PTR_FORMAT, p2i(ptr));
breakpoint();
}
}
#endif // ASSERT
void* os::malloc(size_t size, MEMFLAGS flags) {
return os::malloc(size, flags, CALLER_PC);
}
void* os::malloc(size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
#if INCLUDE_NMT
{
void* rc = NULL;
if (NMTPreInit::handle_malloc(&rc, size)) {
return rc;
}
}
#endif
DEBUG_ONLY(check_crash_protection());
// On malloc(0), implementators of malloc(3) have the choice to return either
// NULL or a unique non-NULL pointer. To unify libc behavior across our platforms
// we chose the latter.
size = MAX2((size_t)1, size);
// For the test flag -XX:MallocMaxTestWords
if (has_reached_max_malloc_test_peak(size)) {
return NULL;
}
const NMT_TrackingLevel level = MemTracker::tracking_level();
const size_t nmt_overhead =
MemTracker::malloc_header_size(level) + MemTracker::malloc_footer_size(level);
const size_t outer_size = size + nmt_overhead;
void* const outer_ptr = (u_char*)::malloc(outer_size);
if (outer_ptr == NULL) {
return NULL;
}
void* inner_ptr = MemTracker::record_malloc((address)outer_ptr, size, memflags, stack, level);
DEBUG_ONLY(break_if_ptr_caught(inner_ptr);)
return inner_ptr;
}
void* os::realloc(void *memblock, size_t size, MEMFLAGS flags) {
return os::realloc(memblock, size, flags, CALLER_PC);
}
void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
#if INCLUDE_NMT
{
void* rc = NULL;
if (NMTPreInit::handle_realloc(&rc, memblock, size)) {
return rc;
}
}
#endif
if (memblock == NULL) {
return os::malloc(size, memflags, stack);
}
DEBUG_ONLY(check_crash_protection());
// On realloc(p, 0), implementators of realloc(3) have the choice to return either
// NULL or a unique non-NULL pointer. To unify libc behavior across our platforms
// we chose the latter.
size = MAX2((size_t)1, size);
// For the test flag -XX:MallocMaxTestWords
if (has_reached_max_malloc_test_peak(size)) {
return NULL;
}
const NMT_TrackingLevel level = MemTracker::tracking_level();
const size_t nmt_overhead =
MemTracker::malloc_header_size(level) + MemTracker::malloc_footer_size(level);
const size_t new_outer_size = size + nmt_overhead;
// If NMT is enabled, this checks for heap overwrites, then de-accounts the old block.
void* const old_outer_ptr = MemTracker::record_free(memblock, level);
void* const new_outer_ptr = ::realloc(old_outer_ptr, new_outer_size);
// If NMT is enabled, this checks for heap overwrites, then de-accounts the old block.
void* const new_inner_ptr = MemTracker::record_malloc(new_outer_ptr, size, memflags, stack, level);
DEBUG_ONLY(break_if_ptr_caught(new_inner_ptr);)
return new_inner_ptr;
}
void os::free(void *memblock) {
#if INCLUDE_NMT
if (NMTPreInit::handle_free(memblock)) {
return;
}
#endif
if (memblock == NULL) {
return;
}
DEBUG_ONLY(break_if_ptr_caught(memblock);)
const NMT_TrackingLevel level = MemTracker::tracking_level();
// If NMT is enabled, this checks for heap overwrites, then de-accounts the old block.
void* const old_outer_ptr = MemTracker::record_free(memblock, level);
::free(old_outer_ptr);
}
void os::init_random(unsigned int initval) {
_rand_seed = initval;
}
int os::next_random(unsigned int rand_seed) {
/* standard, well-known linear congruential random generator with
* next_rand = (16807*seed) mod (2**31-1)
* see
* (1) "Random Number Generators: Good Ones Are Hard to Find",
* S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
* (2) "Two Fast Implementations of the 'Minimal Standard' Random
* Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
*/
const unsigned int a = 16807;
const unsigned int m = 2147483647;
const int q = m / a; assert(q == 127773, "weird math");
const int r = m % a; assert(r == 2836, "weird math");
// compute az=2^31p+q
unsigned int lo = a * (rand_seed & 0xFFFF);
unsigned int hi = a * (rand_seed >> 16);
lo += (hi & 0x7FFF) << 16;
// if q overflowed, ignore the overflow and increment q
if (lo > m) {
lo &= m;
++lo;
}
lo += hi >> 15;
// if (p+q) overflowed, ignore the overflow and increment (p+q)
if (lo > m) {
lo &= m;
++lo;
}
return lo;
}
int os::random() {
// Make updating the random seed thread safe.
while (true) {
unsigned int seed = _rand_seed;
unsigned int rand = next_random(seed);
if (Atomic::cmpxchg(&_rand_seed, seed, rand, memory_order_relaxed) == seed) {
return static_cast<int>(rand);
}
}
}
// The INITIALIZED state is distinguished from the SUSPENDED state because the
// conditions in which a thread is first started are different from those in which
// a suspension is resumed. These differences make it hard for us to apply the
// tougher checks when starting threads that we want to do when resuming them.
// However, when start_thread is called as a result of Thread.start, on a Java
// thread, the operation is synchronized on the Java Thread object. So there
// cannot be a race to start the thread and hence for the thread to exit while
// we are working on it. Non-Java threads that start Java threads either have
// to do so in a context in which races are impossible, or should do appropriate
// locking.
void os::start_thread(Thread* thread) {
OSThread* osthread = thread->osthread();
osthread->set_state(RUNNABLE);
pd_start_thread(thread);
}
void os::abort(bool dump_core) {
abort(dump_core && CreateCoredumpOnCrash, NULL, NULL);
}
//---------------------------------------------------------------------------
// Helper functions for fatal error handler
bool os::print_function_and_library_name(outputStream* st,
address addr,
char* buf, int buflen,
bool shorten_paths,
bool demangle,
bool strip_arguments) {
// If no scratch buffer given, allocate one here on stack.
// (used during error handling; its a coin toss, really, if on-stack allocation
// is worse than (raw) C-heap allocation in that case).
char* p = buf;
if (p == NULL) {
p = (char*)::alloca(O_BUFLEN);
buflen = O_BUFLEN;
}
int offset = 0;
bool have_function_name = dll_address_to_function_name(addr, p, buflen,
&offset, demangle);
bool is_function_descriptor = false;
#ifdef HAVE_FUNCTION_DESCRIPTORS
// When we deal with a function descriptor instead of a real code pointer, try to
// resolve it. There is a small chance that a random pointer given to this function
// may just happen to look like a valid descriptor, but this is rare and worth the
// risk to see resolved function names. But we will print a little suffix to mark
// this as a function descriptor for the reader (see below).
if (!have_function_name && os::is_readable_pointer(addr)) {
address addr2 = (address)os::resolve_function_descriptor(addr);
if (have_function_name = is_function_descriptor =
dll_address_to_function_name(addr2, p, buflen, &offset, demangle)) {
addr = addr2;
}
}
#endif // HAVE_FUNCTION_DESCRIPTORS
if (have_function_name) {
// Print function name, optionally demangled
if (demangle && strip_arguments) {
char* args_start = strchr(p, '(');
if (args_start != NULL) {
*args_start = '\0';
}
}
// Print offset. Omit printing if offset is zero, which makes the output
// more readable if we print function pointers.
if (offset == 0) {
st->print("%s", p);
} else {
st->print("%s+%d", p, offset);
}
} else {
st->print(PTR_FORMAT, p2i(addr));
}
offset = 0;
const bool have_library_name = dll_address_to_library_name(addr, p, buflen, &offset);
if (have_library_name) {
// Cut path parts
if (shorten_paths) {
char* p2 = strrchr(p, os::file_separator()[0]);
if (p2 != NULL) {
p = p2 + 1;
}
}
st->print(" in %s", p);
if (!have_function_name) { // Omit offset if we already printed the function offset
st->print("+%d", offset);
}
}
// Write a trailing marker if this was a function descriptor
if (have_function_name && is_function_descriptor) {
st->print_raw(" (FD)");
}
return have_function_name || have_library_name;
}
void os::print_hex_dump(outputStream* st, address start, address end, int unitsize,
int bytes_per_line, address logical_start) {
assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
start = align_down(start, unitsize);
logical_start = align_down(logical_start, unitsize);
bytes_per_line = align_up(bytes_per_line, 8);
int cols = 0;
int cols_per_line = bytes_per_line / unitsize;
address p = start;
address logical_p = logical_start;
// Print out the addresses as if we were starting from logical_start.
st->print(PTR_FORMAT ": ", p2i(logical_p));
while (p < end) {
if (is_readable_pointer(p)) {
switch (unitsize) {
case 1: st->print("%02x", *(u1*)p); break;
case 2: st->print("%04x", *(u2*)p); break;
case 4: st->print("%08x", *(u4*)p); break;
case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
}
} else {
st->print("%*.*s", 2*unitsize, 2*unitsize, "????????????????");
}
p += unitsize;
logical_p += unitsize;
cols++;
if (cols >= cols_per_line && p < end) {
cols = 0;
st->cr();
st->print(PTR_FORMAT ": ", p2i(logical_p));
} else {
st->print(" ");
}
}
st->cr();
}
void os::print_dhm(outputStream* st, const char* startStr, long sec) {
long days = sec/86400;
long hours = (sec/3600) - (days * 24);
long minutes = (sec/60) - (days * 1440) - (hours * 60);
if (startStr == NULL) startStr = "";
st->print_cr("%s %ld days %ld:%02ld hours", startStr, days, hours, minutes);
}
void os::print_instructions(outputStream* st, address pc, int unitsize) {
st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc));
print_hex_dump(st, pc - 256, pc + 256, unitsize);
}
void os::print_environment_variables(outputStream* st, const char** env_list) {
if (env_list) {
st->print_cr("Environment Variables:");
for (int i = 0; env_list[i] != NULL; i++) {
char *envvar = ::getenv(env_list[i]);
if (envvar != NULL) {
st->print("%s", env_list[i]);
st->print("=");
st->print("%s", envvar);
// Use separate cr() printing to avoid unnecessary buffer operations that might cause truncation.
st->cr();
}
}
}
}
void os::print_cpu_info(outputStream* st, char* buf, size_t buflen) {
// cpu
st->print("CPU:");
#if defined(__APPLE__) && !defined(ZERO)
if (VM_Version::is_cpu_emulated()) {
st->print(" (EMULATED)");
}
#endif
st->print(" total %d", os::processor_count());
// It's not safe to query number of active processors after crash
// st->print("(active %d)", os::active_processor_count()); but we can
// print the initial number of active processors.
// We access the raw value here because the assert in the accessor will
// fail if the crash occurs before initialization of this value.
st->print(" (initial active %d)", _initial_active_processor_count);
st->print(" %s", VM_Version::features_string());
st->cr();
pd_print_cpu_info(st, buf, buflen);
}
// Print a one line string summarizing the cpu, number of cores, memory, and operating system version
void os::print_summary_info(outputStream* st, char* buf, size_t buflen) {
st->print("Host: ");
#ifndef PRODUCT
if (get_host_name(buf, buflen)) {
st->print("%s, ", buf);
}
#endif // PRODUCT
get_summary_cpu_info(buf, buflen);
st->print("%s, ", buf);
size_t mem = physical_memory()/G;
if (mem == 0) { // for low memory systems
mem = physical_memory()/M;
st->print("%d cores, " SIZE_FORMAT "M, ", processor_count(), mem);
} else {
st->print("%d cores, " SIZE_FORMAT "G, ", processor_count(), mem);