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third-party-mirror/openjdk/jdk25u/refs/heads/master/./src/hotspot/share/runtime/os.cpp
blob: 8278abb73e241bdf590fdb5c923289d86aaec478 [file] [edit]
/*
* Copyright (c) 1997, 2025, 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 "cds/cdsConfig.hpp"
#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/vtableStubs.hpp"
#include "gc/shared/gcVMOperations.hpp"
#include "gc/shared/oopStorageSet.hpp"
#include "interpreter/interpreter.hpp"
#include "jvm.h"
#include "logging/log.hpp"
#include "logging/logStream.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/resourceArea.hpp"
#include "memory/universe.hpp"
#include "nmt/mallocHeader.inline.hpp"
#include "nmt/mallocTracker.hpp"
#include "nmt/memTracker.inline.hpp"
#include "nmt/nmtCommon.hpp"
#include "nmt/nmtPreInit.hpp"
#include "oops/compressedKlass.inline.hpp"
#include "oops/oop.inline.hpp"
#include "prims/jvm_misc.hpp"
#include "prims/jvmtiAgent.hpp"
#include "prims/jvmtiAgentList.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/javaThread.hpp"
#include "runtime/jniHandles.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/os.inline.hpp"
#include "runtime/osThread.hpp"
#include "runtime/safefetch.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/threadCrashProtection.hpp"
#include "runtime/threadSMR.hpp"
#include "runtime/vmOperations.hpp"
#include "runtime/vm_version.hpp"
#include "sanitizers/address.hpp"
#include "services/attachListener.hpp"
#include "services/threadService.hpp"
#include "utilities/align.hpp"
#include "utilities/checkedCast.hpp"
#include "utilities/count_trailing_zeros.hpp"
#include "utilities/defaultStream.hpp"
#include "utilities/events.hpp"
#include "utilities/fastrand.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/macros.hpp"
#include "utilities/permitForbiddenFunctions.hpp"
#include "utilities/powerOfTwo.hpp"
#ifdef LINUX
#include "osContainer_linux.hpp"
#endif
#ifndef _WINDOWS
# include <poll.h>
#endif
# include <signal.h>
# include <errno.h>
OSThread* os::_starting_thread = nullptr;
volatile unsigned int os::_rand_seed = 1234567;
int os::_processor_count = 0;
int os::_initial_active_processor_count = 0;
os::PageSizes os::_page_sizes;
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;
}
int os::snprintf_checked(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);
assert(result >= 0, "os::snprintf error");
assert(static_cast<size_t>(result) < len, "os::snprintf truncated");
return result;
}
int os::vsnprintf(char* buf, size_t len, const char* fmt, va_list args) {
int result = permit_forbidden_function::vsnprintf(buf, len, fmt, args);
// If an encoding error occurred (result < 0) then it's not clear
// whether the buffer is NUL terminated, so ensure it is.
if ((result < 0) && (len > 0)) {
buf[len - 1] = '\0';
}
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 == nullptr) {
assert(false, "null buffer");
return nullptr;
}
if (buffer_length < os::iso8601_timestamp_size) {
assert(false, "buffer_length too small");
return nullptr;
}
const int milliseconds_per_second = 1000;
const time_t seconds_since_19700101 =
milliseconds_since_19700101 / milliseconds_per_second;
const int milliseconds_after_second =
checked_cast<int>(milliseconds_since_19700101 % milliseconds_per_second);
// Convert the time value to a tm and timezone variable
struct tm time_struct;
if (utc) {
if (gmtime_pd(&seconds_since_19700101, &time_struct) == nullptr) {
assert(false, "Failed gmtime_pd");
return nullptr;
}
} else {
if (localtime_pd(&seconds_since_19700101, &time_struct) == nullptr) {
assert(false, "Failed localtime_pd");
return nullptr;
}
}
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)) && !defined(AIX)
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 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 int zone_hours = static_cast<int>(abs_local_to_UTC / seconds_per_hour);
const int zone_min =
static_cast<int>((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 nullptr;
}
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);
}
// 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] != nullptr) {
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 != nullptr) {
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()) != nullptr) {
// A list of paths. Search for the path that contains the library.
size_t n;
char** pelements = split_path(pname, &n, fullfnamelen);
if (pelements != nullptr) {
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 == nullptr) ? 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 != nullptr) {
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 != nullptr) {
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) != nullptr)
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, CHECK);
JavaThread* thread = new JavaThread(&signal_thread_entry);
JavaThread::vm_exit_on_osthread_failure(thread);
JavaThread::start_internal_daemon(THREAD, thread, thread_oop, NearMaxPriority);
}
}
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 = nullptr;
void* os::native_java_library() {
if (_native_java_library == nullptr) {
if (is_vm_statically_linked()) {
_native_java_library = get_default_process_handle();
return _native_java_library;
}
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 == nullptr) {
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(JvmtiAgent *agent_lib, bool check_lib, const char *sym) {
assert(agent_lib != nullptr, "sanity check");
void *handle = agent_lib->os_lib();
void *entryName = nullptr;
// If checking then use the agent name otherwise test is_static_lib() to
// see how to process this lookup
const char *lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : nullptr);
char* agent_function_name = build_agent_function_name(sym, lib_name, agent_lib->is_absolute_path());
if (agent_function_name != nullptr) {
entryName = dll_lookup(handle, agent_function_name);
FREE_C_HEAP_ARRAY(char, agent_function_name);
}
return entryName;
}
// See if the passed in agent is statically linked into the VM image.
bool os::find_builtin_agent(JvmtiAgent* agent, const char* sym) {
assert(agent != nullptr, "sanity check");
if (agent->name() == nullptr) {
return false;
}
void* proc_handle = get_default_process_handle();
// Check for Agent_OnLoad/Attach_lib_name function
void* save_handle = agent->os_lib();
// We want to look in this process' symbol table.
agent->set_os_lib(proc_handle);
void* ret = find_agent_function(agent, true, sym);
if (ret != nullptr) {
// Found an entry point like Agent_OnLoad_lib_name so we have a static agent
agent->set_static_lib();
agent->set_loaded();
return true;
}
agent->set_os_lib(save_handle);
return false;
}
// --------------------- heap allocation utilities ---------------------
char *os::strdup(const char *str, MemTag mem_tag) {
size_t size = strlen(str);
char *dup_str = (char *)malloc(size + 1, mem_tag);
if (dup_str == nullptr) return nullptr;
memcpy(dup_str, str, size + 1);
return dup_str;
}
char* os::strdup_check_oom(const char* str, MemTag mem_tag) {
char* p = os::strdup(str, mem_tag);
if (p == nullptr) {
vm_exit_out_of_memory(strlen(str) + 1, OOM_MALLOC_ERROR, "os::strdup_check_oom");
}
return p;
}
#ifdef ASSERT
static void check_crash_protection() {
assert(!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, MemTag mem_tag) {
return os::malloc(size, mem_tag, CALLER_PC);
}
void* os::malloc(size_t size, MemTag mem_tag, const NativeCallStack& stack) {
// Special handling for NMT preinit phase before arguments are parsed
void* rc = nullptr;
if (NMTPreInit::handle_malloc(&rc, size)) {
// No need to fill with 0 because CDS static dumping doesn't use these
// early allocations.
return rc;
}
DEBUG_ONLY(check_crash_protection());
// On malloc(0), implementations 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);
// Observe MallocLimit
if (MemTracker::check_exceeds_limit(size, mem_tag)) {
return nullptr;
}
const size_t outer_size = size + MemTracker::overhead_per_malloc();
// Check for overflow.
if (outer_size < size) {
return nullptr;
}
void* const outer_ptr = permit_forbidden_function::malloc(outer_size);
if (outer_ptr == nullptr) {
return nullptr;
}
void* const inner_ptr = MemTracker::record_malloc((address)outer_ptr, size, mem_tag, stack);
if (CDSConfig::is_dumping_static_archive()) {
// Need to deterministically fill all the alignment gaps in C++ structures.
::memset(inner_ptr, 0, size);
} else if (ZapCHeap) {
::memset(inner_ptr, uninitBlockPad, size);
}
DEBUG_ONLY(break_if_ptr_caught(inner_ptr);)
return inner_ptr;
}
void* os::realloc(void *memblock, size_t size, MemTag mem_tag) {
return os::realloc(memblock, size, mem_tag, CALLER_PC);
}
void* os::realloc(void *memblock, size_t size, MemTag mem_tag, const NativeCallStack& stack) {
// Special handling for NMT preinit phase before arguments are parsed
void* rc = nullptr;
if (NMTPreInit::handle_realloc(&rc, memblock, size, mem_tag)) {
return rc;
}
if (memblock == nullptr) {
return os::malloc(size, mem_tag, stack);
}
DEBUG_ONLY(check_crash_protection());
// On realloc(p, 0), implementers 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);
if (MemTracker::enabled()) {
// NMT realloc handling
const size_t new_outer_size = size + MemTracker::overhead_per_malloc();
// Handle size overflow.
if (new_outer_size < size) {
return nullptr;
}
const size_t old_size = MallocTracker::malloc_header(memblock)->size();
// Observe MallocLimit
if ((size > old_size) && MemTracker::check_exceeds_limit(size - old_size, mem_tag)) {
return nullptr;
}
// Perform integrity checks on and mark the old block as dead *before* calling the real realloc(3) since it
// may invalidate the old block, including its header.
MallocHeader* header = MallocHeader::resolve_checked(memblock);
assert(mem_tag == header->mem_tag(), "weird NMT type mismatch (new:\"%s\" != old:\"%s\")\n",
NMTUtil::tag_to_name(mem_tag), NMTUtil::tag_to_name(header->mem_tag()));
const MallocHeader::FreeInfo free_info = header->free_info();
header->mark_block_as_dead();
// the real realloc
void* const new_outer_ptr = permit_forbidden_function::realloc(header, new_outer_size);
if (new_outer_ptr == nullptr) {
// realloc(3) failed and the block still exists.
// We have however marked it as dead, revert this change.
header->revive();
return nullptr;
}
// realloc(3) succeeded, variable header now points to invalid memory and we need to deaccount the old block.
MemTracker::deaccount(free_info);
// After a successful realloc(3), we account the resized block with its new size
// to NMT.
void* const new_inner_ptr = MemTracker::record_malloc(new_outer_ptr, size, mem_tag, stack);
#ifdef ASSERT
assert(old_size == free_info.size, "Sanity");
if (ZapCHeap && old_size < size) {
// We also zap the newly extended region.
::memset((char*)new_inner_ptr + old_size, uninitBlockPad, size - old_size);
}
#endif
rc = new_inner_ptr;
} else {
// NMT disabled.
rc = permit_forbidden_function::realloc(memblock, size);
if (rc == nullptr) {
return nullptr;
}
}
DEBUG_ONLY(break_if_ptr_caught(rc);)
return rc;
}
void os::free(void *memblock) {
// Special handling for NMT preinit phase before arguments are parsed
if (NMTPreInit::handle_free(memblock)) {
return;
}
if (memblock == nullptr) {
return;
}
DEBUG_ONLY(break_if_ptr_caught(memblock);)
// When NMT is enabled this checks for heap overwrites, then deaccounts the old block.
void* const old_outer_ptr = MemTracker::record_free(memblock);
permit_forbidden_function::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, nullptr, nullptr);
}
//---------------------------------------------------------------------------
// 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 == nullptr) {
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 != nullptr) {
*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 != nullptr) {
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;
}
ATTRIBUTE_NO_ASAN static bool read_safely_from(const uintptr_t* p, uintptr_t* result) {
DEBUG_ONLY(*result = 0xAAAA;)
const uintptr_t errval = 0x1717;
uintptr_t i = (uintptr_t)SafeFetchN((intptr_t*)p, errval);
if (i == errval) {
i = (uintptr_t)SafeFetchN((intptr_t*)p, ~errval);
if (i == ~errval) {
return false;
}
}
(*result) = (uintptr_t)i;
return true;
}
// Helper for os::print_hex_dump
static void print_ascii_form(stringStream& ascii_form, uint64_t value, int unitsize) {
union {
uint64_t v;
uint8_t c[sizeof(v)];
} u = { value };
for (int i = 0; i < unitsize; i++) {
const int idx = LITTLE_ENDIAN_ONLY(i) BIG_ENDIAN_ONLY(sizeof(u.v) - unitsize + i);
const uint8_t c = u.c[idx];
ascii_form.put(isprint(c) && isascii(c) ? c : '.');
}
}
// Helper for os::print_hex_dump
static void print_hex_location(outputStream* st, const_address p, int unitsize, stringStream& ascii_form) {
assert(is_aligned(p, unitsize), "Unaligned");
const uintptr_t* pa = (const uintptr_t*) align_down(p, sizeof(intptr_t));
#ifndef _LP64
// Special handling for printing qwords on 32-bit platforms
if (unitsize == 8) {
uintptr_t i1 = 0, i2 = 0;
if (read_safely_from(pa, &i1) &&
read_safely_from(pa + 1, &i2)) {
const uint64_t value =
LITTLE_ENDIAN_ONLY((((uint64_t)i2) << 32) | i1)
BIG_ENDIAN_ONLY((((uint64_t)i1) << 32) | i2);
st->print(UINT64_FORMAT_0, value);
print_ascii_form(ascii_form, value, unitsize);
} else {
st->print_raw("????????????????");
}
return;
}
#endif // 32-bit, qwords
uintptr_t i = 0;
if (read_safely_from(pa, &i)) {
// bytes: CA FE BA BE DE AD C0 DE
// bytoff: 0 1 2 3 4 5 6 7
// LE bits: 0 8 16 24 32 40 48 56
// BE bits: 56 48 40 32 24 16 8 0
const int offset = (int)(p - (const_address)pa);
const int bitoffset =
LITTLE_ENDIAN_ONLY(offset * BitsPerByte)
BIG_ENDIAN_ONLY((int)((sizeof(intptr_t) - unitsize - offset) * BitsPerByte));
const int bitfieldsize = unitsize * BitsPerByte;
uintptr_t value = bitfield(i, bitoffset, bitfieldsize);
switch (unitsize) {
case 1: st->print("%02x", (u1)value); break;
case 2: st->print("%04x", (u2)value); break;
case 4: st->print("%08x", (u4)value); break;
case 8: st->print(UINT64_FORMAT_0, (u8)value); break;
}
print_ascii_form(ascii_form, value, unitsize);
} else {
switch (unitsize) {
case 1: st->print_raw("??"); break;
case 2: st->print_raw("????"); break;
case 4: st->print_raw("????????"); break;
case 8: st->print_raw("????????????????"); break;
}
}
}
void os::print_hex_dump(outputStream* st, const_address start, const_address end, int unitsize,
bool print_ascii, int bytes_per_line, const_address logical_start, const_address highlight_address) {
constexpr int max_bytes_per_line = 64;
assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
assert(bytes_per_line > 0 && bytes_per_line <= max_bytes_per_line &&
is_power_of_2(bytes_per_line), "invalid bytes_per_line");
assert(highlight_address == nullptr || (highlight_address >= start && highlight_address < end),
"address %p to highlight not in range %p - %p", highlight_address, start, end);
start = align_down(start, unitsize);
logical_start = align_down(logical_start, unitsize);
bytes_per_line = align_up(bytes_per_line, 8);
int cols = 0;
const int cols_per_line = bytes_per_line / unitsize;
const_address p = start;
const_address logical_p = logical_start;
stringStream ascii_form;
// Print out the addresses as if we were starting from logical_start.
while (p < end) {
if (cols == 0) {
// highlight start of line if address of interest is located in the line
const bool should_highlight = (highlight_address >= p && highlight_address < p + bytes_per_line);
const char* const prefix =
(highlight_address != nullptr) ? (should_highlight ? "=>" : " ") : "";
st->print("%s" PTR_FORMAT ": ", prefix, p2i(logical_p));
}
print_hex_location(st, p, unitsize, ascii_form);
p += unitsize;
logical_p += unitsize;
cols++;
if (cols >= cols_per_line) {
if (print_ascii && !ascii_form.is_empty()) {
st->print(" %s", ascii_form.base());
}
ascii_form.reset();
st->cr();
cols = 0;
} else {
st->print(" ");
}
}
if (cols > 0) { // did not print a full line
if (print_ascii) {
// indent last ascii part to match that of full lines
const int size_of_printed_unit = unitsize * 2;
const int space_left = (cols_per_line - cols) * (size_of_printed_unit + 1);
st->sp(space_left);
st->print(" %s", ascii_form.base());
}
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 == nullptr) startStr = "";
st->print_cr("%s %ld days %ld:%02ld hours", startStr, days, hours, minutes);
}
void os::print_tos_pc(outputStream* st, const void* context) {
if (context == nullptr) return;
// First of all, carefully determine sp without inspecting memory near pc.
// See comment below.
intptr_t* sp = nullptr;
fetch_frame_from_context(context, &sp, nullptr);
print_tos(st, (address)sp);
st->cr();
// Note: it may be unsafe to inspect memory near pc. For example, pc may
// point to garbage if entry point in an nmethod is corrupted. Leave
// this at the end, and hope for the best.
// This version of fetch_frame_from_context finds the caller pc if the actual
// one is bad.
address pc = fetch_frame_from_context(context).pc();
print_instructions(st, pc);
st->cr();
}
void os::print_tos(outputStream* st, address sp) {
st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp));
print_hex_dump(st, sp, sp + 512, sizeof(intptr_t));
}
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, /* print_ascii=*/false, pc);
}
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] != nullptr; i++) {
char *envvar = ::getenv(env_list[i]);
if (envvar != nullptr) {
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_jvmti_agent_info(outputStream* st) {
#if INCLUDE_JVMTI
const JvmtiAgentList::Iterator it = JvmtiAgentList::all();
if (it.has_next()) {
st->print_cr("JVMTI agents:");
} else {
st->print_cr("JVMTI agents: none");
}
while (it.has_next()) {
const JvmtiAgent* agent = it.next();
if (agent != nullptr) {
const char* dyninfo = agent->is_dynamic() ? "dynamic " : "";
const char* instrumentinfo = agent->is_instrument_lib() ? "instrumentlib " : "";
const char* loadinfo = agent->is_loaded() ? "loaded" : "not loaded";
const char* initinfo = agent->is_initialized() ? "initialized" : "not initialized";
const char* optionsinfo = agent->options();
const char* pathinfo = agent->os_lib_path();
if (optionsinfo == nullptr) optionsinfo = "none";
if (pathinfo == nullptr) pathinfo = "none";
st->print_cr("%s path:%s, %s, %s, %s%soptions:%s", agent->name(), pathinfo, loadinfo, initinfo, dyninfo, instrumentinfo, optionsinfo);
}
}
#endif
}
void os::print_register_info(outputStream* st, const void* context) {
int continuation = 0;
print_register_info(st, context, continuation);
}
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::cpu_info_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, %zuM, ", processor_count(), mem);
} else {
st->print("%d cores, %zuG, ", processor_count(), mem);
}
get_summary_os_info(buf, buflen);
st->print_raw(buf);
st->cr();
}
static constexpr int secs_per_day = 86400;
static constexpr int secs_per_hour = 3600;
static constexpr int secs_per_min = 60;
void os::print_date_and_time(outputStream *st, char* buf, size_t buflen) {
time_t tloc;
(void)time(&tloc);
char* timestring = ctime(&tloc); // ctime adds newline.
// edit out the newline
char* nl = strchr(timestring, '\n');
if (nl != nullptr) {
*nl = '\0';
}
struct tm tz;
if (localtime_pd(&tloc, &tz) != nullptr) {
wchar_t w_buf[80];
size_t n = ::wcsftime(w_buf, 80, L"%Z", &tz);
if (n > 0 && ::wcstombs(buf, w_buf, buflen) != (size_t)-1) {
st->print("Time: %s %s", timestring, buf);
} else {
st->print("Time: %s", timestring);
}
} else {
st->print("Time: %s", timestring);
}
double t = os::elapsedTime();
st->print(" elapsed time: ");
print_elapsed_time(st, t);
st->cr();
}
void os::print_elapsed_time(outputStream* st, double time) {
// NOTE: a crash using printf("%f",...) on Linux was historically noted here.
int eltime = (int)time; // elapsed time in seconds
int eltimeFraction = (int) ((time - eltime) * 1000000);
// print elapsed time in a human-readable format:
int eldays = eltime / secs_per_day;
int day_secs = eldays * secs_per_day;
int elhours = (eltime - day_secs) / secs_per_hour;
int hour_secs = elhours * secs_per_hour;
int elmins = (eltime - day_secs - hour_secs) / secs_per_min;
int minute_secs = elmins * secs_per_min;
int elsecs = (eltime - day_secs - hour_secs - minute_secs);
st->print("%d.%06d seconds (%dd %dh %dm %ds)", eltime, eltimeFraction, eldays, elhours, elmins, elsecs);
}
// Check if pointer can be read from (4-byte read access).
// Helps to prove validity of a non-null pointer.
// Returns true in very early stages of VM life when stub is not yet generated.
bool os::is_readable_pointer(const void* p) {
int* const aligned = (int*) align_down((intptr_t)p, 4);
int cafebabe = 0xcafebabe; // tester value 1
int deadbeef = 0xdeadbeef; // tester value 2
return (SafeFetch32(aligned, cafebabe) != cafebabe) || (SafeFetch32(aligned, deadbeef) != deadbeef);
}
bool os::is_readable_range(const void* from, const void* to) {
if ((uintptr_t)from >= (uintptr_t)to) return false;
for (uintptr_t p = align_down((uintptr_t)from, min_page_size()); p < (uintptr_t)to; p += min_page_size()) {
if (!is_readable_pointer((const void*)p)) {
return false;
}
}
return true;
}
// moved from debug.cpp (used to be find()) but still called from there
// The verbose parameter is only set by the debug code in one case
void os::print_location(outputStream* st, intptr_t x, bool verbose) {
address addr = (address)x;
// Handle null first, so later checks don't need to protect against it.
if (addr == nullptr) {
st->print_cr("0x0 is null");
return;
}
// Check if addr points into a code blob.
CodeBlob* b = CodeCache::find_blob(addr);
if (b != nullptr) {
b->dump_for_addr(addr, st, verbose);
return;
}
// Check if addr points into Java heap.
if (Universe::heap()->print_location(st, addr)) {
return;
}
#if !INCLUDE_ASAN
bool accessible = is_readable_pointer(addr);
// Check if addr points into the narrow Klass protection zone
if (UseCompressedClassPointers && CompressedKlassPointers::is_in_protection_zone(addr)) {
st->print_cr(PTR_FORMAT " points into nKlass protection zone", p2i(addr));
return;
}
// Check if addr is a JNI handle.
if (align_down((intptr_t)addr, sizeof(intptr_t)) != 0 && accessible) {
if (JNIHandles::is_global_handle((jobject) addr)) {
st->print_cr(INTPTR_FORMAT " is a global jni handle", p2i(addr));
return;
}
if (JNIHandles::is_weak_global_handle((jobject) addr)) {
st->print_cr(INTPTR_FORMAT " is a weak global jni handle", p2i(addr));
return;
}
}
// Check if addr belongs to a Java thread.
for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
// If the addr is a java thread print information about that.
if (addr == (address)thread) {
if (verbose) {
thread->print_on(st);
} else {
st->print_cr(INTPTR_FORMAT " is a thread", p2i(addr));
}
return;
}
// If the addr is in the stack region for this thread then report that
// and print thread info
if (thread->is_in_full_stack(addr)) {
st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
INTPTR_FORMAT, p2i(addr), p2i(thread));
if (verbose) thread->print_on(st);
return;
}
}
// Check if in metaspace and print types that have vptrs
if (Metaspace::initialized() && Metaspace::contains(addr)) {
if (Klass::is_valid((Klass*)addr)) {
st->print_cr(INTPTR_FORMAT " is a pointer to class: ", p2i(addr));
((Klass*)addr)->print_on(st);
} else if (Method::is_valid_method((const Method*)addr)) {
((Method*)addr)->print_value_on(st);
st->cr();
} else {
// Use addr->print() from the debugger instead (not here)
st->print_cr(INTPTR_FORMAT " is pointing into metadata", p2i(addr));
}
return;
}
// Compressed klass needs to be decoded first.
#ifdef _LP64
if (UseCompressedClassPointers && ((uintptr_t)addr &~ (uintptr_t)max_juint) == 0) {
narrowKlass narrow_klass = (narrowKlass)(uintptr_t)addr;
Klass* k = CompressedKlassPointers::decode_without_asserts(narrow_klass);
if (Klass::is_valid(k)) {
st->print_cr(UINT32_FORMAT " is a compressed pointer to class: " INTPTR_FORMAT, narrow_klass, p2i((HeapWord*)k));
k->print_on(st);
return;
}
}
#endif
// Ask if any OopStorage knows about this address.
if (OopStorageSet::print_containing(addr, st)) {
return;
}
// Still nothing? If NMT is enabled, we can ask what it thinks...
if (MemTracker::print_containing_region(addr, st)) {
return;
}
// Try an OS specific find
if (os::find(addr, st)) {
return;
}
if (accessible) {
st->print(INTPTR_FORMAT " points into unknown readable memory:", p2i(addr));
if (is_aligned(addr, sizeof(intptr_t))) {
st->print(" " PTR_FORMAT " |", *(intptr_t*)addr);
}
for (address p = addr; p < align_up(addr + 1, sizeof(intptr_t)); ++p) {
st->print(" %02x", *(u1*)p);
}
st->cr();
return;
}
#endif // !INCLUDE_ASAN
st->print_cr(INTPTR_FORMAT " is an unknown value", p2i(addr));
}
static bool is_pointer_bad(intptr_t* ptr) {
return !is_aligned(ptr, sizeof(uintptr_t)) || !os::is_readable_pointer(ptr);
}
// Looks like all platforms can use the same function to check if C
// stack is walkable beyond current frame.
// Returns true if this is not the case, i.e. the frame is possibly
// the first C frame on the stack.
bool os::is_first_C_frame(frame* fr) {
#ifdef _WINDOWS
return true; // native stack isn't walkable on windows this way.
#endif
// Load up sp, fp, sender sp and sender fp, check for reasonable values.
// Check usp first, because if that's bad the other accessors may fault
// on some architectures. Ditto ufp second, etc.
if (is_pointer_bad(fr->sp())) return true;
uintptr_t ufp = (uintptr_t)fr->fp();
if (is_pointer_bad(fr->fp())) return true;
uintptr_t old_sp = (uintptr_t)fr->sender_sp();
if ((uintptr_t)fr->sender_sp() == (uintptr_t)-1 || is_pointer_bad(fr->sender_sp())) return true;
uintptr_t old_fp = (uintptr_t)fr->link_or_null();
if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp ||
is_pointer_bad(fr->link_or_null())) return true;
// stack grows downwards; if old_fp is below current fp or if the stack
// frame is too large, either the stack is corrupted or fp is not saved
// on stack (i.e. on x86, ebp may be used as general register). The stack
// is not walkable beyond current frame.
if (old_fp < ufp) return true;
if (old_fp - ufp > 64 * K) return true;
return false;
}
// Set up the boot classpath.
char* os::format_boot_path(const char* format_string,
const char* home,
int home_len,
char fileSep,
char pathSep) {
assert((fileSep == '/' && pathSep == ':') ||
(fileSep == '\\' && pathSep == ';'), "unexpected separator chars");
// Scan the format string to determine the length of the actual
// boot classpath, and handle platform dependencies as well.
int formatted_path_len = 0;
const char* p;
for (p = format_string; *p != 0; ++p) {
if (*p == '%') formatted_path_len += home_len - 1;
++formatted_path_len;
}
char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal);
// Create boot classpath from format, substituting separator chars and
// java home directory.
char* q = formatted_path;
for (p = format_string; *p != 0; ++p) {
switch (*p) {
case '%':
strcpy(q, home);
q += home_len;
break;
case '/':
*q++ = fileSep;
break;
case ':':
*q++ = pathSep;
break;
default:
*q++ = *p;
}
}
*q = '\0';
assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
return formatted_path;
}
// This function is a proxy to fopen, it tries to add a non standard flag ('e' or 'N')
// that ensures automatic closing of the file on exec. If it can not find support in
// the underlying c library, it will make an extra system call (fcntl) to ensure automatic
// closing of the file on exec.
FILE* os::fopen(const char* path, const char* mode) {
char modified_mode[20];
assert(strlen(mode) + 1 < sizeof(modified_mode), "mode chars plus one extra must fit in buffer");
os::snprintf_checked(modified_mode, sizeof(modified_mode), "%s" LINUX_ONLY("e") BSD_ONLY("e") WINDOWS_ONLY("N"), mode);
FILE* file = ::fopen(path, modified_mode);
#if !(defined LINUX || defined BSD || defined _WINDOWS)
// assume fcntl FD_CLOEXEC support as a backup solution when 'e' or 'N'
// is not supported as mode in fopen
if (file != nullptr) {
int fd = fileno(file);
if (fd != -1) {
int fd_flags = fcntl(fd, F_GETFD);
if (fd_flags != -1) {
fcntl(fd, F_SETFD, fd_flags | FD_CLOEXEC);
}
}
}
#endif
return file;
}
bool os::set_boot_path(char fileSep, char pathSep) {
const char* home = Arguments::get_java_home();
int home_len = (int)strlen(home);
struct stat st;
// modular image if "modules" jimage exists
char* jimage = format_boot_path("%/lib/" MODULES_IMAGE_NAME, home, home_len, fileSep, pathSep);
if (jimage == nullptr) return false;
bool has_jimage = (os::stat(jimage, &st) == 0);
if (has_jimage) {
Arguments::set_boot_class_path(jimage, true);
FREE_C_HEAP_ARRAY(char, jimage);
return true;
}
FREE_C_HEAP_ARRAY(char, jimage);
// check if developer build with exploded modules
char* base_classes = format_boot_path("%/modules/" JAVA_BASE_NAME, home, home_len, fileSep, pathSep);
if (base_classes == nullptr) return false;
if (os::stat(base_classes, &st) == 0) {
Arguments::set_boot_class_path(base_classes, false);
FREE_C_HEAP_ARRAY(char, base_classes);
return true;
}
FREE_C_HEAP_ARRAY(char, base_classes);
return false;
}
static char* _image_release_file_content = nullptr;
void os::read_image_release_file() {
assert(_image_release_file_content == nullptr, "release file content must not be already set");
const char* home = Arguments::get_java_home();
stringStream ss;
ss.print("%s/release", home);
FILE* file = fopen(ss.base(), "rb");
if (file == nullptr) {
return;
}
fseek(file, 0, SEEK_END);
long sz = ftell(file);
if (sz == -1) {
fclose(file);
return;
}
fseek(file, 0, SEEK_SET);
char* tmp = (char*) os::malloc(sz + 1, mtInternal);
if (tmp == nullptr) {
fclose(file);
return;
}
size_t elements_read = fread(tmp, 1, sz, file);
if (elements_read < (size_t)sz) {
tmp[elements_read] = '\0';
} else {
tmp[sz] = '\0';
}
// issues with \r in line endings on Windows, so better replace those
for (size_t i = 0; i < elements_read; i++) {
if (tmp[i] == '\r') {
tmp[i] = ' ';
}
}
Atomic::release_store(&_image_release_file_content, tmp);
fclose(file);
}
void os::print_image_release_file(outputStream* st) {
char* ifrc = Atomic::load_acquire(&_image_release_file_content);
if (ifrc != nullptr) {
st->print_cr("%s", ifrc);
} else {
st->print_cr("<release file has not been read>");
}
}
bool os::file_exists(const char* filename) {
struct stat statbuf;
if (filename == nullptr || strlen(filename) == 0) {
return false;
}
return os::stat(filename, &statbuf) == 0;
}
bool os::write(int fd, const void *buf, size_t nBytes) {
ssize_t res;
while (nBytes > 0) {
res = pd_write(fd, buf, nBytes);
if (res == OS_ERR) {
return false;
}
buf = (void *)((char *)buf + res);
nBytes -= res;
}
return true;
}
// Splits a path, based on its separator, the number of
// elements is returned back in "elements".
// file_name_length is used as a modifier for each path's
// length when compared to JVM_MAXPATHLEN. So if you know
// each returned path will have something appended when
// in use, you can pass the length of that in
// file_name_length, to ensure we detect if any path
// exceeds the maximum path length once prepended onto
// the sub-path/file name.
// It is the callers responsibility to:
// a> check the value of "elements", which may be 0.
// b> ignore any empty path elements
// c> free up the data.
char** os::split_path(const char* path, size_t* elements, size_t file_name_length) {
*elements = (size_t)0;
if (path == nullptr || strlen(path) == 0 || file_name_length == (size_t)nullptr) {
return nullptr;
}
const char psepchar = *os::path_separator();
char* inpath = NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal);
strcpy(inpath, path);
size_t count = 1;
char* p = strchr(inpath, psepchar);
// Get a count of elements to allocate memory
while (p != nullptr) {
count++;
p++;
p = strchr(p, psepchar);
}
char** opath = NEW_C_HEAP_ARRAY(char*, count, mtInternal);
// do the actual splitting
p = inpath;
for (size_t i = 0 ; i < count ; i++) {
size_t len = strcspn(p, os::path_separator());
if (len + file_name_length > JVM_MAXPATHLEN) {
// release allocated storage before exiting the vm
free_array_of_char_arrays(opath, i++);
vm_exit_during_initialization("The VM tried to use a path that exceeds the maximum path length for "
"this system. Review path-containing parameters and properties, such as "
"sun.boot.library.path, to identify potential sources for this path.");
}
// allocate the string and add terminator storage
char* s = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
strncpy(s, p, len);
s[len] = '\0';
opath[i] = s;
p += len + 1;
}
FREE_C_HEAP_ARRAY(char, inpath);
*elements = count;
return opath;
}
// Returns true if the current stack pointer is above the stack shadow
// pages, false otherwise.
bool os::stack_shadow_pages_available(Thread *thread, const methodHandle& method, address sp) {
if (!thread->is_Java_thread()) return false;
// Check if we have StackShadowPages above the guard zone. This parameter
// is dependent on the depth of the maximum VM call stack possible from
// the handler for stack overflow. 'instanceof' in the stack overflow
// handler or a println uses at least 8k stack of VM and native code
// respectively.
const int framesize_in_bytes =
Interpreter::size_top_interpreter_activation(method()) * wordSize;
address limit = JavaThread::cast(thread)->stack_overflow_state()->shadow_zone_safe_limit();
return sp > (limit + framesize_in_bytes);
}
size_t os::page_size_for_region(size_t region_size, size_t min_pages, bool must_be_aligned) {
assert(min_pages > 0, "sanity");
if (UseLargePages) {
const size_t max_page_size = region_size / min_pages;
for (size_t page_size = page_sizes().largest(); page_size != 0;
page_size = page_sizes().next_smaller(page_size)) {
if (page_size <= max_page_size) {
if (!must_be_aligned || is_aligned(region_size, page_size)) {
return page_size;
}
}
}
}
return vm_page_size();
}
size_t os::page_size_for_region_aligned(size_t region_size, size_t min_pages) {
return page_size_for_region(region_size, min_pages, true);
}
size_t os::page_size_for_region_unaligned(size_t region_size, size_t min_pages) {
return page_size_for_region(region_size, min_pages, false);
}
#ifndef MAX_PATH
#define MAX_PATH (2 * K)
#endif
void os::pause() {
char filename[MAX_PATH];
if (PauseAtStartupFile && PauseAtStartupFile[0]) {
jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
} else {
jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
}
int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
if (fd != -1) {
struct stat buf;
::close(fd);
while (::stat(filename, &buf) == 0) {
#if defined(_WINDOWS)
Sleep(100);
#else
(void)::poll(nullptr, 0, 100);
#endif
}
} else {
jio_fprintf(stderr,
"Could not open pause file '%s', continuing immediately.\n", filename);
}
}
static const char* errno_to_string (int e, bool short_text) {
#define ALL_SHARED_ENUMS(X) \
X(E2BIG, "Argument list too long") \
X(EACCES, "Permission denied") \
X(EADDRINUSE, "Address in use") \
X(EADDRNOTAVAIL, "Address not available") \
X(EAFNOSUPPORT, "Address family not supported") \
X(EAGAIN, "Resource unavailable, try again") \
X(EALREADY, "Connection already in progress") \
X(EBADF, "Bad file descriptor") \
X(EBADMSG, "Bad message") \
X(EBUSY, "Device or resource busy") \
X(ECANCELED, "Operation canceled") \
X(ECHILD, "No child processes") \
X(ECONNABORTED, "Connection aborted") \
X(ECONNREFUSED, "Connection refused") \
X(ECONNRESET, "Connection reset") \
X(EDEADLK, "Resource deadlock would occur") \
X(EDESTADDRREQ, "Destination address required") \
X(EDOM, "Mathematics argument out of domain of function") \
X(EEXIST, "File exists") \
X(EFAULT, "Bad address") \
X(EFBIG, "File too large") \
X(EHOSTUNREACH, "Host is unreachable") \
X(EIDRM, "Identifier removed") \
X(EILSEQ, "Illegal byte sequence") \
X(EINPROGRESS, "Operation in progress") \
X(EINTR, "Interrupted function") \
X(EINVAL, "Invalid argument") \
X(EIO, "I/O error") \
X(EISCONN, "Socket is connected") \
X(EISDIR, "Is a directory") \
X(ELOOP, "Too many levels of symbolic links") \
X(EMFILE, "Too many open files") \
X(EMLINK, "Too many links") \
X(EMSGSIZE, "Message too large") \
X(ENAMETOOLONG, "Filename too long") \
X(ENETDOWN, "Network is down") \
X(ENETRESET, "Connection aborted by network") \
X(ENETUNREACH, "Network unreachable") \
X(ENFILE, "Too many files open in system") \
X(ENOBUFS, "No buffer space available") \
X(ENODATA, "No message is available on the STREAM head read queue") \
X(ENODEV, "No such device") \
X(ENOENT, "No such file or directory") \
X(ENOEXEC, "Executable file format error") \
X(ENOLCK, "No locks available") \
X(ENOLINK, "Reserved") \
X(ENOMEM, "Not enough space") \
X(ENOMSG, "No message of the desired type") \
X(ENOPROTOOPT, "Protocol not available") \
X(ENOSPC, "No space left on device") \
X(ENOSR, "No STREAM resources") \
X(ENOSTR, "Not a STREAM") \
X(ENOSYS, "Function not supported") \
X(ENOTCONN, "The socket is not connected") \
X(ENOTDIR, "Not a directory") \
X(ENOTEMPTY, "Directory not empty") \
X(ENOTSOCK, "Not a socket") \
X(ENOTSUP, "Not supported") \
X(ENOTTY, "Inappropriate I/O control operation") \
X(ENXIO, "No such device or address") \
X(EOPNOTSUPP, "Operation not supported on socket") \
X(EOVERFLOW, "Value too large to be stored in data type") \
X(EPERM, "Operation not permitted") \
X(EPIPE, "Broken pipe") \
X(EPROTO, "Protocol error") \
X(EPROTONOSUPPORT, "Protocol not supported") \
X(EPROTOTYPE, "Protocol wrong type for socket") \
X(ERANGE, "Result too large") \
X(EROFS, "Read-only file system") \
X(ESPIPE, "Invalid seek") \
X(ESRCH, "No such process") \
X(ETIME, "Stream ioctl() timeout") \
X(ETIMEDOUT, "Connection timed out") \
X(ETXTBSY, "Text file busy") \
X(EWOULDBLOCK, "Operation would block") \
X(EXDEV, "Cross-device link")
#define DEFINE_ENTRY(e, text) { e, #e, text },
static const struct {
int v;
const char* short_text;
const char* long_text;
} table [] = {
ALL_SHARED_ENUMS(DEFINE_ENTRY)
// The following enums are not defined on all platforms.
#ifdef ESTALE
DEFINE_ENTRY(ESTALE, "Reserved")
#endif
#ifdef EDQUOT
DEFINE_ENTRY(EDQUOT, "Reserved")
#endif
#ifdef EMULTIHOP
DEFINE_ENTRY(EMULTIHOP, "Reserved")
#endif
// End marker.
{ -1, "Unknown errno", "Unknown error" }
};
#undef DEFINE_ENTRY
#undef ALL_FLAGS
int i = 0;
while (table[i].v != -1 && table[i].v != e) {
i ++;
}
return short_text ? table[i].short_text : table[i].long_text;
}
const char* os::strerror(int e) {
return errno_to_string(e, false);
}
const char* os::errno_name(int e) {
return errno_to_string(e, true);
}
// create binary file, rewriting existing file if required
int os::create_binary_file(const char* path, bool rewrite_existing) {
int oflags = O_WRONLY | O_CREAT WINDOWS_ONLY(| O_BINARY);
oflags |= rewrite_existing ? O_TRUNC : O_EXCL;
return ::open(path, oflags, S_IREAD | S_IWRITE);
}
void os::trace_page_sizes(const char* str,
const size_t region_min_size,
const size_t region_max_size,
const char* base,
const size_t size,
const size_t page_size) {
log_info(pagesize)("%s: "
" min=" EXACTFMT
" max=" EXACTFMT
" base=" PTR_FORMAT
" size=" EXACTFMT
" page_size=" EXACTFMT,
str,
EXACTFMTARGS(region_min_size),
EXACTFMTARGS(region_max_size),
p2i(base),
EXACTFMTARGS(size),
EXACTFMTARGS(page_size));
}
void os::trace_page_sizes_for_requested_size(const char* str,
const size_t requested_size,
const size_t requested_page_size,
const char* base,
const size_t size,
const size_t page_size) {
log_info(pagesize)("%s:"
" req_size=" EXACTFMT
" req_page_size=" EXACTFMT
" base=" PTR_FORMAT
" size=" EXACTFMT
" page_size=" EXACTFMT,
str,
EXACTFMTARGS(requested_size),
EXACTFMTARGS(requested_page_size),
p2i(base),
EXACTFMTARGS(size),
EXACTFMTARGS(page_size));
}
// This is the working definition of a server class machine:
// >= 2 physical CPU's and >=2GB of memory, with some fuzz
// because the graphics memory (?) sometimes masks physical memory.
// If you want to change the definition of a server class machine
// on some OS or platform, e.g., >=4GB on Windows platforms,
// then you'll have to parameterize this method based on that state,
// as was done for logical processors here, or replicate and
// specialize this method for each platform. (Or fix os to have
// some inheritance structure and use subclassing. Sigh.)
// If you want some platform to always or never behave as a server
// class machine, change the setting of AlwaysActAsServerClassMachine
// and NeverActAsServerClassMachine in globals*.hpp.
bool os::is_server_class_machine() {
// First check for the early returns
if (NeverActAsServerClassMachine) {
return false;
}
if (AlwaysActAsServerClassMachine) {
return true;
}
// Then actually look at the machine
bool result = false;
const unsigned int server_processors = 2;
const julong server_memory = 2UL * G;
// We seem not to get our full complement of memory.
// We allow some part (1/8?) of the memory to be "missing",
// based on the sizes of DIMMs, and maybe graphics cards.
const julong missing_memory = 256UL * M;
/* Is this a server class machine? */
if ((os::active_processor_count() >= (int)server_processors) &&
(os::physical_memory() >= (server_memory - missing_memory))) {
const unsigned int logical_processors =
VM_Version::logical_processors_per_package();
if (logical_processors > 1) {
const unsigned int physical_packages =
os::active_processor_count() / logical_processors;
if (physical_packages >= server_processors) {
result = true;
}
} else {
result = true;
}
}
return result;
}
void os::initialize_initial_active_processor_count() {
assert(_initial_active_processor_count == 0, "Initial active processor count already set.");
_initial_active_processor_count = active_processor_count();
log_debug(os)("Initial active processor count set to %d" , _initial_active_processor_count);
}
bool os::create_stack_guard_pages(char* addr, size_t bytes) {
return os::pd_create_stack_guard_pages(addr, bytes);
}
char* os::reserve_memory(size_t bytes, MemTag mem_tag, bool executable) {
char* result = pd_reserve_memory(bytes, executable);
if (result != nullptr) {
MemTracker::record_virtual_memory_reserve(result, bytes, CALLER_PC, mem_tag);
log_debug(os, map)("Reserved " RANGEFMT, RANGEFMTARGS(result, bytes));
} else {
log_info(os, map)("Reserve failed (%zu bytes)", bytes);
}
return result;
}
char* os::attempt_reserve_memory_at(char* addr, size_t bytes, MemTag mem_tag, bool executable) {
char* result = SimulateFullAddressSpace ? nullptr : pd_attempt_reserve_memory_at(addr, bytes, executable);
if (result != nullptr) {
MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC, mem_tag);
log_debug(os, map)("Reserved " RANGEFMT, RANGEFMTARGS(result, bytes));
} else {
log_info(os, map)("Attempt to reserve " RANGEFMT " failed",
RANGEFMTARGS(addr, bytes));
}
return result;
}
#ifdef ASSERT
static void print_points(const char* s, unsigned* points, unsigned num) {
stringStream ss;
for (unsigned i = 0; i < num; i ++) {
ss.print("%u ", points[i]);
}
log_trace(os, map)("%s, %u Points: %s", s, num, ss.base());
}
#endif
// Helper for os::attempt_reserve_memory_between
// Given an array of things, shuffle them (Fisher-Yates)
template <typename T>
static void shuffle_fisher_yates(T* arr, unsigned num, FastRandom& frand) {
for (unsigned i = num - 1; i >= 1; i--) {
unsigned j = frand.next() % i;
swap(arr[i], arr[j]);
}
}
// Helper for os::attempt_reserve_memory_between
// Given an array of things, do a hemisphere split such that the resulting
// order is: [first, last, first + 1, last - 1, ...]
template <typename T>
static void hemi_split(T* arr, unsigned num) {
T* tmp = (T*)::alloca(sizeof(T) * num);
for (unsigned i = 0; i < num; i++) {
tmp[i] = arr[i];
}
for (unsigned i = 0; i < num; i++) {
arr[i] = is_even(i) ? tmp[i / 2] : tmp[num - (i / 2) - 1];
}
}
// Given an address range [min, max), attempts to reserve memory within this area, with the given alignment.
// If randomize is true, the location will be randomized.
char* os::attempt_reserve_memory_between(char* min, char* max, size_t bytes, size_t alignment, bool randomize) {
// Please keep the following constants in sync with the companion gtests:
// Number of mmap attemts we will undertake.
constexpr unsigned max_attempts = 32;
// In randomization mode: We require a minimum number of possible attach points for
// randomness. Below that we refuse to reserve anything.
constexpr unsigned min_random_value_range = 16;
// In randomization mode: If the possible value range is below this threshold, we
// use a total shuffle without regard for address space fragmentation, otherwise
// we attempt to minimize fragmentation.
constexpr unsigned total_shuffle_threshold = 1024;
#define ARGSFMT "range [" PTR_FORMAT "-" PTR_FORMAT "), size 0x%zx, alignment 0x%zx, randomize: %d"
#define ARGSFMTARGS p2i(min), p2i(max), bytes, alignment, randomize
log_debug(os, map) ("reserve_between (" ARGSFMT ")", ARGSFMTARGS);
assert(is_power_of_2(alignment), "alignment invalid (" ARGSFMT ")", ARGSFMTARGS);
assert(alignment < SIZE_MAX / 2, "alignment too large (" ARGSFMT ")", ARGSFMTARGS);
assert(is_aligned(bytes, os::vm_page_size()), "size not page aligned (" ARGSFMT ")", ARGSFMTARGS);
assert(max >= min, "invalid range (" ARGSFMT ")", ARGSFMTARGS);
char* const absolute_max = (char*)(NOT_LP64(G * 3) LP64_ONLY(G * 128 * 1024));
char* const absolute_min = (char*) os::vm_min_address();
// AIX is the only platform that uses System V shm for reserving virtual memory.
// In this case, the required alignment of the allocated size (64K) and the alignment
// of possible start points of the memory region (256M) differ.
// This is not reflected by os_allocation_granularity().
// The logic here is dual to the one in pd_reserve_memory in os_aix.cpp
const size_t system_allocation_granularity =
AIX_ONLY((!os::Aix::supports_64K_mmap_pages() && os::vm_page_size() == 64*K) ? 256*M : ) os::vm_allocation_granularity();
const size_t alignment_adjusted = MAX2(alignment, system_allocation_granularity);
// Calculate first and last possible attach points:
if (!can_align_up(MAX2(absolute_min, min), alignment_adjusted)) {
return nullptr; // overflow
}
char* const lo_att = align_up(MAX2(absolute_min, min), alignment_adjusted);
char* const hi_end = MIN2(max, absolute_max);
if ((uintptr_t)hi_end <= bytes) {
return nullptr; // no need to go on
}
char* const hi_att = align_down(hi_end - bytes, alignment_adjusted);
if (hi_att > max) {
return nullptr; // overflow
}
// no possible attach points
if (hi_att < lo_att) {
return nullptr;
}
char* result = nullptr;
const size_t num_attach_points = (size_t)((hi_att - lo_att) / alignment_adjusted) + 1;
assert(num_attach_points > 0, "Sanity");
// If this fires, the input range is too large for the given alignment (we work
// with int below to keep things simple). Since alignment is bound to page size,
// and the lowest page size is 4K, this gives us a minimum of 4K*4G=8TB address
// range.
assert(num_attach_points <= UINT_MAX,
"Too many possible attach points - range too large or alignment too small (" ARGSFMT ")", ARGSFMTARGS);
const unsigned num_attempts = MIN2((unsigned)num_attach_points, max_attempts);
unsigned points[max_attempts];
if (randomize) {
FastRandom frand;
if (num_attach_points < min_random_value_range) {
return nullptr;
}
// We pre-calc the attach points:
// 1 We divide the attach range into equidistant sections and calculate an attach
// point within each section.
// 2 We wiggle those attach points around within their section (depends on attach
// point granularity)
// 3 Should that not be enough to get effective randomization, shuffle all
// attach points
// 4 Otherwise, re-order them to get an optimized probing sequence.
const unsigned stepsize = (unsigned)num_attach_points / num_attempts;
const unsigned half = num_attempts / 2;
// 1+2: pre-calc points
for (unsigned i = 0; i < num_attempts; i++) {
const unsigned deviation = stepsize > 1 ? (frand.next() % stepsize) : 0;
points[i] = (i * stepsize) + deviation;
}
if (num_attach_points < total_shuffle_threshold) {
// 3:
// The numeber of possible attach points is too low for the "wiggle" from
// point 2 to be enough to provide randomization. In that case, shuffle
// all attach points at the cost of possible fragmentation (e.g. if we
// end up mapping into the middle of the range).
shuffle_fisher_yates(points, num_attempts, frand);
} else {
// 4
// We have a large enough number of attach points to satisfy the randomness
// goal without. In that case, we optimize probing by sorting the attach
// points: We attempt outermost points first, then work ourselves up to
// the middle. That reduces address space fragmentation. We also alternate
// hemispheres, which increases the chance of successfull mappings if the
// previous mapping had been blocked by large maps.
hemi_split(points, num_attempts);
}
} // end: randomized
else
{
// Non-randomized. We just attempt to reserve by probing sequentially. We
// alternate between hemispheres, working ourselves up to the middle.
const int stepsize = (unsigned)num_attach_points / num_attempts;
for (unsigned i = 0; i < num_attempts; i++) {
points[i] = (i * stepsize);
}
hemi_split(points, num_attempts);
}
#ifdef ASSERT
// Print + check all pre-calculated attach points
print_points("before reserve", points, num_attempts);
for (unsigned i = 0; i < num_attempts; i++) {
assert(points[i] < num_attach_points, "Candidate attach point %d out of range (%u, num_attach_points: %zu) " ARGSFMT,
i, points[i], num_attach_points, ARGSFMTARGS);
}
#endif
// Now reserve
for (unsigned i = 0; result == nullptr && i < num_attempts; i++) {
const unsigned candidate_offset = points[i];
char* const candidate = lo_att + candidate_offset * alignment_adjusted;
assert(candidate <= hi_att, "Invalid offset %u (" ARGSFMT ")", candidate_offset, ARGSFMTARGS);
result = SimulateFullAddressSpace ? nullptr : os::pd_attempt_reserve_memory_at(candidate, bytes, false);
if (!result) {
log_trace(os, map)("Failed to attach at " PTR_FORMAT, p2i(candidate));
}
}
// Sanity checks, logging, NMT stuff:
if (result != nullptr) {
#define ERRFMT "result: " PTR_FORMAT " " ARGSFMT
#define ERRFMTARGS p2i(result), ARGSFMTARGS
assert(result >= min, "OOB min (" ERRFMT ")", ERRFMTARGS);
assert((result + bytes) <= max, "OOB max (" ERRFMT ")", ERRFMTARGS);
assert(result >= (char*)os::vm_min_address(), "OOB vm.map min (" ERRFMT ")", ERRFMTARGS);
assert((result + bytes) <= absolute_max, "OOB vm.map max (" ERRFMT ")", ERRFMTARGS);
assert(is_aligned(result, alignment), "alignment invalid (" ERRFMT ")", ERRFMTARGS);
log_trace(os, map)(ERRFMT, ERRFMTARGS);
log_debug(os, map)("successfully attached at " PTR_FORMAT, p2i(result));
MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC, mtNone);
} else {
log_debug(os, map)("failed to attach anywhere in [" PTR_FORMAT "-" PTR_FORMAT ")", p2i(min), p2i(max));
}
return result;
#undef ARGSFMT
#undef ERRFMT
#undef ARGSFMTARGS
#undef ERRFMTARGS
}
static void assert_nonempty_range(const char* addr, size_t bytes) {
assert(addr != nullptr && bytes > 0, "invalid range [" PTR_FORMAT ", " PTR_FORMAT ")",
p2i(addr), p2i(addr) + bytes);
}
julong os::used_memory() {
#ifdef LINUX
if (OSContainer::is_containerized()) {
jlong mem_usage = OSContainer::memory_usage_in_bytes();
if (mem_usage > 0) {
return mem_usage;
}
}
#endif
return os::physical_memory() - os::available_memory();
}
bool os::commit_memory(char* addr, size_t bytes, bool executable) {
assert_nonempty_range(addr, bytes);
bool res = pd_commit_memory(addr, bytes, executable);
if (res) {
MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
log_debug(os, map)("Committed " RANGEFMT, RANGEFMTARGS(addr, bytes));
} else {
log_info(os, map)("Failed to commit " RANGEFMT, RANGEFMTARGS(addr, bytes));
}
return res;
}
bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
bool executable) {
assert_nonempty_range(addr, size);
bool res = os::pd_commit_memory(addr, size, alignment_hint, executable);
if (res) {
MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
log_debug(os, map)("Committed " RANGEFMT, RANGEFMTARGS(addr, size));
} else {
log_info(os, map)("Failed to commit " RANGEFMT, RANGEFMTARGS(addr, size));
}
return res;
}
void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable,
const char* mesg) {
assert_nonempty_range(addr, bytes);
pd_commit_memory_or_exit(addr, bytes, executable, mesg);
MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
}
void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint,
bool executable, const char* mesg) {
assert_nonempty_range(addr, size);
os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg);
MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
}
// The scope of NmtVirtualMemoryLocker covers both pd_uncommit_memory and record_virtual_memory_uncommit because
// these operations must happen atomically to avoid races causing NMT to fall out os sync with the OS reality.
// We do not have the same lock protection for pd_commit_memory and record_virtual_memory_commit.
// We assume that there is some external synchronization that prevents a region from being uncommitted
// before it is finished being committed.
bool os::uncommit_memory(char* addr, size_t bytes, bool executable) {
assert_nonempty_range(addr, bytes);
bool res;
if (MemTracker::enabled()) {
MemTracker::NmtVirtualMemoryLocker nvml;
res = pd_uncommit_memory(addr, bytes, executable);
if (res) {
MemTracker::record_virtual_memory_uncommit(addr, bytes);
}
} else {
res = pd_uncommit_memory(addr, bytes, executable);
}
if (res) {
log_debug(os, map)("Uncommitted " RANGEFMT, RANGEFMTARGS(addr, bytes));
} else {
log_info(os, map)("Failed to uncommit " RANGEFMT, RANGEFMTARGS(addr, bytes));
}
return res;
}
// The scope of NmtVirtualMemoryLocker covers both pd_release_memory and record_virtual_memory_release because
// these operations must happen atomically to avoid races causing NMT to fall out os sync with the OS reality.
// We do not have the same lock protection for pd_reserve_memory and record_virtual_memory_reserve.
// We assume that there is some external synchronization that prevents a region from being released
// before it is finished being reserved.
bool os::release_memory(char* addr, size_t bytes) {
assert_nonempty_range(addr, bytes);
bool res;
if (MemTracker::enabled()) {
MemTracker::NmtVirtualMemoryLocker nvml;
res = pd_release_memory(addr, bytes);
if (res) {
MemTracker::record_virtual_memory_release(addr, bytes);
}
} else {
res = pd_release_memory(addr, bytes);
}
if (!res) {
log_info(os, map)("Failed to release " RANGEFMT, RANGEFMTARGS(addr, bytes));
} else {
log_debug(os, map)("Released " RANGEFMT, RANGEFMTARGS(addr, bytes));
}
return res;
}
// Prints all mappings
void os::print_memory_mappings(outputStream* st) {
os::print_memory_mappings(nullptr, SIZE_MAX, st);
}
// Pretouching must use a store, not just a load. On many OSes loads from
// fresh memory would be satisfied from a single mapped page containing all
// zeros. We need to store something to each page to get them backed by
// their own memory, which is the effect we want here. An atomic add of
// zero is used instead of a simple store, allowing the memory to be used
// while pretouch is in progress, rather than requiring users of the memory
// to wait until the entire range has been touched. This is technically
// a UB data race, but doesn't cause any problems for us.
void os::pretouch_memory(void* start, void* end, size_t page_size) {
assert(start <= end, "invalid range: " PTR_FORMAT " -> " PTR_FORMAT, p2i(start), p2i(end));
assert(is_power_of_2(page_size), "page size misaligned: %zu", page_size);
assert(page_size >= sizeof(int), "page size too small: %zu", page_size);
if (start < end) {
// We're doing concurrent-safe touch and memory state has page
// granularity, so we can touch anywhere in a page. Touch at the
// beginning of each page to simplify iteration.
void* first = align_down(start, page_size);
void* last = align_down(static_cast<char*>(end) - 1, page_size);
assert(first <= last, "invariant");
const size_t pd_page_size = pd_pretouch_memory(first, last, page_size);
if (pd_page_size > 0) {
// Iterate from first page through last (inclusive), being careful to
// avoid overflow if the last page abuts the end of the address range.
last = align_down(static_cast<char*>(end) - 1, pd_page_size);
for (char* cur = static_cast<char*>(first); /* break */; cur += pd_page_size) {
Atomic::add(reinterpret_cast<int*>(cur), 0, memory_order_relaxed);
if (cur >= last) break;
}
}
}
}
char* os::map_memory_to_file(size_t bytes, int file_desc, MemTag mem_tag) {
// Could have called pd_reserve_memory() followed by replace_existing_mapping_with_file_mapping(),
// but AIX may use SHM in which case its more trouble to detach the segment and remap memory to the file.
// On all current implementations null is interpreted as any available address.
char* result = os::map_memory_to_file(nullptr /* addr */, bytes, file_desc);
if (result != nullptr) {
MemTracker::record_virtual_memory_reserve_and_commit(result, bytes, CALLER_PC, mem_tag);
}
return result;
}
char* os::attempt_map_memory_to_file_at(char* addr, size_t bytes, int file_desc, MemTag mem_tag) {
char* result = pd_attempt_map_memory_to_file_at(addr, bytes, file_desc);
if (result != nullptr) {
MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC, mem_tag);
}
return result;
}
char* os::map_memory(int fd, const char* file_name, size_t file_offset,
char *addr, size_t bytes, MemTag mem_tag,
bool read_only, bool allow_exec) {
char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec);
if (result != nullptr) {
MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC, mem_tag);
}
return result;
}
bool os::unmap_memory(char *addr, size_t bytes) {
bool result;
if (MemTracker::enabled()) {
MemTracker::NmtVirtualMemoryLocker nvml;
result = pd_unmap_memory(addr, bytes);
if (result) {
MemTracker::record_virtual_memory_release(addr, bytes);
}
} else {
result = pd_unmap_memory(addr, bytes);
}
return result;
}
void os::disclaim_memory(char *addr, size_t bytes) {
pd_disclaim_memory(addr, bytes);
}
void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
pd_realign_memory(addr, bytes, alignment_hint);
}
char* os::reserve_memory_special(size_t size, size_t alignment, size_t page_size,
char* addr, bool executable) {
assert(is_aligned(addr, alignment), "Unaligned request address");
char* result = pd_reserve_memory_special(size, alignment, page_size, addr, executable);
if (result != nullptr) {
// The memory is committed
MemTracker::record_virtual_memory_reserve_and_commit((address)result, size, CALLER_PC, mtNone);
log_debug(os, map)("Reserved and committed " RANGEFMT, RANGEFMTARGS(result, size));
} else {
log_info(os, map)("Reserve and commit failed (%zu bytes)", size);
}
return result;
}
bool os::release_memory_special(char* addr, size_t bytes) {
bool res;
if (MemTracker::enabled()) {
MemTracker::NmtVirtualMemoryLocker nvml;
res = pd_release_memory_special(addr, bytes);
if (res) {
MemTracker::record_virtual_memory_release(addr, bytes);
}
} else {
res = pd_release_memory_special(addr, bytes);
}
return res;
}
// Convenience wrapper around naked_short_sleep to allow for longer sleep
// times. Only for use by non-JavaThreads.
void os::naked_sleep(jlong millis) {
assert(!Thread::current()->is_Java_thread(), "not for use by JavaThreads");
const jlong limit = 999;
while (millis > limit) {
naked_short_sleep(limit);
millis -= limit;
}
naked_short_sleep(millis);
}
////// Implementation of PageSizes
void os::PageSizes::add(size_t page_size) {
assert(is_power_of_2(page_size), "page_size must be a power of 2: 0x%zx", page_size);
_v |= page_size;
}
bool os::PageSizes::contains(size_t page_size) const {
assert(is_power_of_2(page_size), "page_size must be a power of 2: 0x%zx", page_size);
return (_v & page_size) != 0;
}
size_t os::PageSizes::next_smaller(size_t page_size) const {
assert(is_power_of_2(page_size), "page_size must be a power of 2: 0x%zx", page_size);
size_t v2 = _v & (page_size - 1);
if (v2 == 0) {
return 0;
}
return round_down_power_of_2(v2);
}
size_t os::PageSizes::next_larger(size_t page_size) const {
assert(is_power_of_2(page_size), "page_size must be a power of 2: 0x%zx", page_size);
if (page_size == max_power_of_2<size_t>()) { // Shift by 32/64 would be UB
return 0;
}
// Remove current and smaller page sizes
size_t v2 = _v & ~(page_size + (page_size - 1));
if (v2 == 0) {
return 0;
}
return (size_t)1 << count_trailing_zeros(v2);
}
size_t os::PageSizes::largest() const {
const size_t max = max_power_of_2<size_t>();
if (contains(max)) {
return max;
}
return next_smaller(max);
}
size_t os::PageSizes::smallest() const {
// Strictly speaking the set should not contain sizes < os::vm_page_size().
// But this is not enforced.
return next_larger(1);
}
void os::PageSizes::print_on(outputStream* st) const {
bool first = true;
for (size_t sz = smallest(); sz != 0; sz = next_larger(sz)) {
if (first) {
first = false;
} else {
st->print_raw(", ");
}
if (sz < M) {
st->print("%zuk", sz / K);
} else if (sz < G) {
st->print("%zuM", sz / M);
} else {
st->print("%zuG", sz / G);
}
}
if (first) {
st->print("empty");
}
}
// Check minimum allowable stack sizes for thread creation and to initialize
// the java system classes, including StackOverflowError - depends on page
// size.
// The space needed for frames during startup is platform dependent. It
// depends on word size, platform calling conventions, C frame layout and
// interpreter/C1/C2 design decisions. Therefore this is given in a
// platform (os/cpu) dependent constant.
// To this, space for guard mechanisms is added, which depends on the
// page size which again depends on the concrete system the VM is running
// on. Space for libc guard pages is not included in this size.
jint os::set_minimum_stack_sizes() {
_java_thread_min_stack_allowed = _java_thread_min_stack_allowed +
StackOverflow::stack_guard_zone_size() +
StackOverflow::stack_shadow_zone_size();
_java_thread_min_stack_allowed = align_up(_java_thread_min_stack_allowed, vm_page_size());
_java_thread_min_stack_allowed = MAX2(_java_thread_min_stack_allowed, _os_min_stack_allowed);
size_t stack_size_in_bytes = ThreadStackSize * K;
if (stack_size_in_bytes != 0 &&
stack_size_in_bytes < _java_thread_min_stack_allowed) {
// The '-Xss' and '-XX:ThreadStackSize=N' options both set
// ThreadStackSize so we go with "Java thread stack size" instead
// of "ThreadStackSize" to be more friendly.
tty->print_cr("\nThe Java thread stack size specified is too small. "
"Specify at least %zuk",
_java_thread_min_stack_allowed / K);
return JNI_ERR;
}
// Make the stack size a multiple of the page size so that
// the yellow/red zones can be guarded.
JavaThread::set_stack_size_at_create(align_up(stack_size_in_bytes, vm_page_size()));
// Reminder: a compiler thread is a Java thread.
_compiler_thread_min_stack_allowed = _compiler_thread_min_stack_allowed +
StackOverflow::stack_guard_zone_size() +
StackOverflow::stack_shadow_zone_size();
_compiler_thread_min_stack_allowed = align_up(_compiler_thread_min_stack_allowed, vm_page_size());
_compiler_thread_min_stack_allowed = MAX2(_compiler_thread_min_stack_allowed, _os_min_stack_allowed);
stack_size_in_bytes = CompilerThreadStackSize * K;
if (stack_size_in_bytes != 0 &&
stack_size_in_bytes < _compiler_thread_min_stack_allowed) {
tty->print_cr("\nThe CompilerThreadStackSize specified is too small. "
"Specify at least %zuk",
_compiler_thread_min_stack_allowed / K);
return JNI_ERR;
}
_vm_internal_thread_min_stack_allowed = align_up(_vm_internal_thread_min_stack_allowed, vm_page_size());
_vm_internal_thread_min_stack_allowed = MAX2(_vm_internal_thread_min_stack_allowed, _os_min_stack_allowed);
stack_size_in_bytes = VMThreadStackSize * K;
if (stack_size_in_bytes != 0 &&
stack_size_in_bytes < _vm_internal_thread_min_stack_allowed) {
tty->print_cr("\nThe VMThreadStackSize specified is too small. "
"Specify at least %zuk",
_vm_internal_thread_min_stack_allowed / K);
return JNI_ERR;
}
return JNI_OK;
}
// Builds a platform dependent Agent_OnLoad_<lib_name> function name
// which is used to find statically linked in agents.
// Parameters:
// sym_name: Symbol in library we are looking for
// lib_name: Name of library to look in, null for shared libs.
// is_absolute_path == true if lib_name is absolute path to agent
// such as "C:/a/b/L.dll" or "/a/b/libL.so"
// == false if only the base name of the library is passed in
// such as "L"
char* os::build_agent_function_name(const char *sym_name, const char *lib_name,
bool is_absolute_path) {
char *agent_entry_name;
size_t len = 0;
size_t name_len = 0;
size_t prefix_len = strlen(JNI_LIB_PREFIX);
size_t suffix_len = strlen(JNI_LIB_SUFFIX);
size_t underscore_len = 0; // optional underscore if lib_name is set
const char *start;
if (lib_name != nullptr) {
if (is_absolute_path) {
// Need to strip path, prefix and suffix
if ((start = strrchr(lib_name, *os::file_separator())) != nullptr) {
lib_name = ++start;
}
#ifdef _WINDOWS
else { // Need to check for drive prefix e.g. C:L.dll
if ((start = strchr(lib_name, ':')) != nullptr) {
lib_name = ++start;
}
}
#endif
name_len = strlen(lib_name);
if (name_len <= (prefix_len + suffix_len)) {
return nullptr;
}
lib_name += prefix_len;
name_len = strlen(lib_name) - suffix_len;
} else {
name_len = strlen(lib_name);
}
underscore_len = 1;
}
// Total buffer length to allocate - includes null terminator.
len = strlen(sym_name) + underscore_len + name_len + 1;
agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread);
if (agent_entry_name == nullptr) {
return nullptr;
}
strcpy(agent_entry_name, sym_name);
if (lib_name != nullptr) {
strcat(agent_entry_name, "_");
strncat(agent_entry_name, lib_name, name_len);
}
return agent_entry_name;
}