/*
* Copyright (c) 1999, 2022, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2015, 2022 SAP SE. 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.
*
*/
// no precompiled headers
#include "classfile/vmSymbols.hpp"
#include "code/icBuffer.hpp"
#include "code/vtableStubs.hpp"
#include "compiler/compileBroker.hpp"
#include "compiler/disassembler.hpp"
#include "interpreter/interpreter.hpp"
#include "jvm.h"
#include "jvmtifiles/jvmti.h"
#include "logging/log.hpp"
#include "logging/logStream.hpp"
#include "memory/allocation.inline.hpp"
#include "oops/oop.inline.hpp"
#include "os_linux.inline.hpp"
#include "os_posix.inline.hpp"
#include "osContainer_linux.hpp"
#include "prims/jniFastGetField.hpp"
#include "prims/jvm_misc.hpp"
#include "runtime/arguments.hpp"
#include "runtime/atomic.hpp"
#include "runtime/globals.hpp"
#include "runtime/globals_extension.hpp"
#include "runtime/init.hpp"
#include "runtime/interfaceSupport.inline.hpp"
#include "runtime/java.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/javaThread.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/objectMonitor.hpp"
#include "runtime/osInfo.hpp"
#include "runtime/osThread.hpp"
#include "runtime/perfMemory.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/statSampler.hpp"
#include "runtime/stubRoutines.hpp"
#include "runtime/threadCritical.hpp"
#include "runtime/threads.hpp"
#include "runtime/threadSMR.hpp"
#include "runtime/timer.hpp"
#include "runtime/vm_version.hpp"
#include "signals_posix.hpp"
#include "semaphore_posix.hpp"
#include "services/memTracker.hpp"
#include "services/runtimeService.hpp"
#include "utilities/align.hpp"
#include "utilities/decoder.hpp"
#include "utilities/defaultStream.hpp"
#include "utilities/events.hpp"
#include "utilities/elfFile.hpp"
#include "utilities/growableArray.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/macros.hpp"
#include "utilities/powerOfTwo.hpp"
#include "utilities/vmError.hpp"
// put OS-includes here
# include <sys/types.h>
# include <sys/mman.h>
# include <sys/stat.h>
# include <sys/select.h>
# include <pthread.h>
# include <signal.h>
# include <endian.h>
# include <errno.h>
# include <dlfcn.h>
# include <stdio.h>
# include <unistd.h>
# include <sys/resource.h>
# include <pthread.h>
# include <sys/stat.h>
# include <sys/time.h>
# include <sys/times.h>
# include <sys/utsname.h>
# include <sys/socket.h>
# include <pwd.h>
# include <poll.h>
# include <fcntl.h>
# include <string.h>
# include <syscall.h>
# include <sys/sysinfo.h>
# include <sys/ipc.h>
# include <sys/shm.h>
# include <link.h>
# include <stdint.h>
# include <inttypes.h>
# include <sys/ioctl.h>
# include <linux/elf-em.h>
#ifdef __GLIBC__
# include <malloc.h>
#endif
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#include <sched.h>
#undef _GNU_SOURCE
#else
#include <sched.h>
#endif
// if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
// getrusage() is prepared to handle the associated failure.
#ifndef RUSAGE_THREAD
#define RUSAGE_THREAD (1) /* only the calling thread */
#endif
#define MAX_PATH (2 * K)
#define MAX_SECS 100000000
// for timer info max values which include all bits
#define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
#ifdef MUSL_LIBC
// dlvsym is not a part of POSIX
// and musl libc doesn't implement it.
static void *dlvsym(void *handle,
const char *symbol,
const char *version) {
// load the latest version of symbol
return dlsym(handle, symbol);
}
#endif
enum CoredumpFilterBit {
FILE_BACKED_PVT_BIT = 1 << 2,
FILE_BACKED_SHARED_BIT = 1 << 3,
LARGEPAGES_BIT = 1 << 6,
DAX_SHARED_BIT = 1 << 8
};
////////////////////////////////////////////////////////////////////////////////
// global variables
julong os::Linux::_physical_memory = 0;
address os::Linux::_initial_thread_stack_bottom = NULL;
uintptr_t os::Linux::_initial_thread_stack_size = 0;
int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
pthread_t os::Linux::_main_thread;
bool os::Linux::_supports_fast_thread_cpu_time = false;
const char * os::Linux::_libc_version = NULL;
const char * os::Linux::_libpthread_version = NULL;
size_t os::Linux::_default_large_page_size = 0;
#ifdef __GLIBC__
// We want to be buildable and runnable on older and newer glibcs, so resolve both
// mallinfo and mallinfo2 dynamically.
struct old_mallinfo {
int arena;
int ordblks;
int smblks;
int hblks;
int hblkhd;
int usmblks;
int fsmblks;
int uordblks;
int fordblks;
int keepcost;
};
typedef struct old_mallinfo (*mallinfo_func_t)(void);
static mallinfo_func_t g_mallinfo = NULL;
struct new_mallinfo {
size_t arena;
size_t ordblks;
size_t smblks;
size_t hblks;
size_t hblkhd;
size_t usmblks;
size_t fsmblks;
size_t uordblks;
size_t fordblks;
size_t keepcost;
};
typedef struct new_mallinfo (*mallinfo2_func_t)(void);
static mallinfo2_func_t g_mallinfo2 = NULL;
#endif // __GLIBC__
static int clock_tics_per_sec = 100;
// If the VM might have been created on the primordial thread, we need to resolve the
// primordial thread stack bounds and check if the current thread might be the
// primordial thread in places. If we know that the primordial thread is never used,
// such as when the VM was created by one of the standard java launchers, we can
// avoid this
static bool suppress_primordial_thread_resolution = false;
// utility functions
julong os::available_memory() {
return Linux::available_memory();
}
julong os::Linux::available_memory() {
// values in struct sysinfo are "unsigned long"
struct sysinfo si;
julong avail_mem;
if (OSContainer::is_containerized()) {
jlong mem_limit = OSContainer::memory_limit_in_bytes();
jlong mem_usage;
if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) {
log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage);
}
if (mem_limit > 0 && mem_usage > 0) {
avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0;
log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem);
return avail_mem;
}
}
sysinfo(&si);
avail_mem = (julong)si.freeram * si.mem_unit;
log_trace(os)("available memory: " JULONG_FORMAT, avail_mem);
return avail_mem;
}
julong os::physical_memory() {
jlong phys_mem = 0;
if (OSContainer::is_containerized()) {
jlong mem_limit;
if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) {
log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit);
return mem_limit;
}
}
phys_mem = Linux::physical_memory();
log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem);
return phys_mem;
}
static uint64_t initial_total_ticks = 0;
static uint64_t initial_steal_ticks = 0;
static bool has_initial_tick_info = false;
static void next_line(FILE *f) {
int c;
do {
c = fgetc(f);
} while (c != '\n' && c != EOF);
}
bool os::Linux::get_tick_information(CPUPerfTicks* pticks, int which_logical_cpu) {
FILE* fh;
uint64_t userTicks, niceTicks, systemTicks, idleTicks;
// since at least kernel 2.6 : iowait: time waiting for I/O to complete
// irq: time servicing interrupts; softirq: time servicing softirqs
uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0;
// steal (since kernel 2.6.11): time spent in other OS when running in a virtualized environment
uint64_t stealTicks = 0;
// guest (since kernel 2.6.24): time spent running a virtual CPU for guest OS under the
// control of the Linux kernel
uint64_t guestNiceTicks = 0;
int logical_cpu = -1;
const int required_tickinfo_count = (which_logical_cpu == -1) ? 4 : 5;
int n;
memset(pticks, 0, sizeof(CPUPerfTicks));
if ((fh = os::fopen("/proc/stat", "r")) == NULL) {
return false;
}
if (which_logical_cpu == -1) {
n = fscanf(fh, "cpu " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
UINT64_FORMAT " " UINT64_FORMAT " ",
&userTicks, &niceTicks, &systemTicks, &idleTicks,
&iowTicks, &irqTicks, &sirqTicks,
&stealTicks, &guestNiceTicks);
} else {
// Move to next line
next_line(fh);
// find the line for requested cpu faster to just iterate linefeeds?
for (int i = 0; i < which_logical_cpu; i++) {
next_line(fh);
}
n = fscanf(fh, "cpu%u " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
UINT64_FORMAT " " UINT64_FORMAT " ",
&logical_cpu, &userTicks, &niceTicks,
&systemTicks, &idleTicks, &iowTicks, &irqTicks, &sirqTicks,
&stealTicks, &guestNiceTicks);
}
fclose(fh);
if (n < required_tickinfo_count || logical_cpu != which_logical_cpu) {
return false;
}
pticks->used = userTicks + niceTicks;
pticks->usedKernel = systemTicks + irqTicks + sirqTicks;
pticks->total = userTicks + niceTicks + systemTicks + idleTicks +
iowTicks + irqTicks + sirqTicks + stealTicks + guestNiceTicks;
if (n > required_tickinfo_count + 3) {
pticks->steal = stealTicks;
pticks->has_steal_ticks = true;
} else {
pticks->steal = 0;
pticks->has_steal_ticks = false;
}
return true;
}
#ifndef SYS_gettid
// i386: 224, ia64: 1105, amd64: 186, sparc: 143
#ifdef __ia64__
#define SYS_gettid 1105
#else
#ifdef __i386__
#define SYS_gettid 224
#else
#ifdef __amd64__
#define SYS_gettid 186
#else
#ifdef __sparc__
#define SYS_gettid 143
#else
#error define gettid for the arch
#endif
#endif
#endif
#endif
#endif
// pid_t gettid()
//
// Returns the kernel thread id of the currently running thread. Kernel
// thread id is used to access /proc.
pid_t os::Linux::gettid() {
int rslt = syscall(SYS_gettid);
assert(rslt != -1, "must be."); // old linuxthreads implementation?
return (pid_t)rslt;
}
// Returns the amount of swap currently configured, in bytes.
// This can change at any time.
julong os::Linux::host_swap() {
struct sysinfo si;
sysinfo(&si);
return (julong)si.totalswap;
}
// Most versions of linux have a bug where the number of processors are
// determined by looking at the /proc file system. In a chroot environment,
// the system call returns 1.
static bool unsafe_chroot_detected = false;
static const char *unstable_chroot_error = "/proc file system not found.\n"
"Java may be unstable running multithreaded in a chroot "
"environment on Linux when /proc filesystem is not mounted.";
void os::Linux::initialize_system_info() {
set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
if (processor_count() == 1) {
pid_t pid = os::Linux::gettid();
char fname[32];
jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
FILE *fp = os::fopen(fname, "r");
if (fp == NULL) {
unsafe_chroot_detected = true;
} else {
fclose(fp);
}
}
_physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
assert(processor_count() > 0, "linux error");
}
void os::init_system_properties_values() {
// The next steps are taken in the product version:
//
// Obtain the JAVA_HOME value from the location of libjvm.so.
// This library should be located at:
// <JAVA_HOME>/lib/{client|server}/libjvm.so.
//
// If "/jre/lib/" appears at the right place in the path, then we
// assume libjvm.so is installed in a JDK and we use this path.
//
// Otherwise exit with message: "Could not create the Java virtual machine."
//
// The following extra steps are taken in the debugging version:
//
// If "/jre/lib/" does NOT appear at the right place in the path
// instead of exit check for $JAVA_HOME environment variable.
//
// If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
// then we append a fake suffix "hotspot/libjvm.so" to this path so
// it looks like libjvm.so is installed there
// <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
//
// Otherwise exit.
//
// Important note: if the location of libjvm.so changes this
// code needs to be changed accordingly.
// See ld(1):
// The linker uses the following search paths to locate required
// shared libraries:
// 1: ...
// ...
// 7: The default directories, normally /lib and /usr/lib.
#ifndef OVERRIDE_LIBPATH
#if defined(_LP64)
#define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
#else
#define DEFAULT_LIBPATH "/lib:/usr/lib"
#endif
#else
#define DEFAULT_LIBPATH OVERRIDE_LIBPATH
#endif
// Base path of extensions installed on the system.
#define SYS_EXT_DIR "/usr/java/packages"
#define EXTENSIONS_DIR "/lib/ext"
// Buffer that fits several sprintfs.
// Note that the space for the colon and the trailing null are provided
// by the nulls included by the sizeof operator.
const size_t bufsize =
MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
(size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
char *buf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
// sysclasspath, java_home, dll_dir
{
char *pslash;
os::jvm_path(buf, bufsize);
// Found the full path to libjvm.so.
// Now cut the path to <java_home>/jre if we can.
pslash = strrchr(buf, '/');
if (pslash != NULL) {
*pslash = '\0'; // Get rid of /libjvm.so.
}
pslash = strrchr(buf, '/');
if (pslash != NULL) {
*pslash = '\0'; // Get rid of /{client|server|hotspot}.
}
Arguments::set_dll_dir(buf);
if (pslash != NULL) {
pslash = strrchr(buf, '/');
if (pslash != NULL) {
*pslash = '\0'; // Get rid of /lib.
}
}
Arguments::set_java_home(buf);
if (!set_boot_path('/', ':')) {
vm_exit_during_initialization("Failed setting boot class path.", NULL);
}
}
// Where to look for native libraries.
//
// Note: Due to a legacy implementation, most of the library path
// is set in the launcher. This was to accommodate linking restrictions
// on legacy Linux implementations (which are no longer supported).
// Eventually, all the library path setting will be done here.
//
// However, to prevent the proliferation of improperly built native
// libraries, the new path component /usr/java/packages is added here.
// Eventually, all the library path setting will be done here.
{
// Get the user setting of LD_LIBRARY_PATH, and prepended it. It
// should always exist (until the legacy problem cited above is
// addressed).
const char *v = ::getenv("LD_LIBRARY_PATH");
const char *v_colon = ":";
if (v == NULL) { v = ""; v_colon = ""; }
// That's +1 for the colon and +1 for the trailing '\0'.
char *ld_library_path = NEW_C_HEAP_ARRAY(char,
strlen(v) + 1 +
sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1,
mtInternal);
sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon);
Arguments::set_library_path(ld_library_path);
FREE_C_HEAP_ARRAY(char, ld_library_path);
}
// Extensions directories.
sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
Arguments::set_ext_dirs(buf);
FREE_C_HEAP_ARRAY(char, buf);
#undef DEFAULT_LIBPATH
#undef SYS_EXT_DIR
#undef EXTENSIONS_DIR
}
////////////////////////////////////////////////////////////////////////////////
// breakpoint support
void os::breakpoint() {
BREAKPOINT;
}
extern "C" void breakpoint() {
// use debugger to set breakpoint here
}
//////////////////////////////////////////////////////////////////////////////
// detecting pthread library
void os::Linux::libpthread_init() {
// Save glibc and pthread version strings.
#if !defined(_CS_GNU_LIBC_VERSION) || \
!defined(_CS_GNU_LIBPTHREAD_VERSION)
#error "glibc too old (< 2.3.2)"
#endif
#ifdef MUSL_LIBC
// confstr() from musl libc returns EINVAL for
// _CS_GNU_LIBC_VERSION and _CS_GNU_LIBPTHREAD_VERSION
os::Linux::set_libc_version("musl - unknown");
os::Linux::set_libpthread_version("musl - unknown");
#else
size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
assert(n > 0, "cannot retrieve glibc version");
char *str = (char *)malloc(n, mtInternal);
confstr(_CS_GNU_LIBC_VERSION, str, n);
os::Linux::set_libc_version(str);
n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
assert(n > 0, "cannot retrieve pthread version");
str = (char *)malloc(n, mtInternal);
confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
os::Linux::set_libpthread_version(str);
#endif
}
/////////////////////////////////////////////////////////////////////////////
// thread stack expansion
// os::Linux::manually_expand_stack() takes care of expanding the thread
// stack. Note that this is normally not needed: pthread stacks allocate
// thread stack using mmap() without MAP_NORESERVE, so the stack is already
// committed. Therefore it is not necessary to expand the stack manually.
//
// Manually expanding the stack was historically needed on LinuxThreads
// thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
// it is kept to deal with very rare corner cases:
//
// For one, user may run the VM on an own implementation of threads
// whose stacks are - like the old LinuxThreads - implemented using
// mmap(MAP_GROWSDOWN).
//
// Also, this coding may be needed if the VM is running on the primordial
// thread. Normally we avoid running on the primordial thread; however,
// user may still invoke the VM on the primordial thread.
//
// The following historical comment describes the details about running
// on a thread stack allocated with mmap(MAP_GROWSDOWN):
// Force Linux kernel to expand current thread stack. If "bottom" is close
// to the stack guard, caller should block all signals.
//
// MAP_GROWSDOWN:
// A special mmap() flag that is used to implement thread stacks. It tells
// kernel that the memory region should extend downwards when needed. This
// allows early versions of LinuxThreads to only mmap the first few pages
// when creating a new thread. Linux kernel will automatically expand thread
// stack as needed (on page faults).
//
// However, because the memory region of a MAP_GROWSDOWN stack can grow on
// demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
// region, it's hard to tell if the fault is due to a legitimate stack
// access or because of reading/writing non-exist memory (e.g. buffer
// overrun). As a rule, if the fault happens below current stack pointer,
// Linux kernel does not expand stack, instead a SIGSEGV is sent to the
// application (see Linux kernel fault.c).
//
// This Linux feature can cause SIGSEGV when VM bangs thread stack for
// stack overflow detection.
//
// Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
// not use MAP_GROWSDOWN.
//
// To get around the problem and allow stack banging on Linux, we need to
// manually expand thread stack after receiving the SIGSEGV.
//
// There are two ways to expand thread stack to address "bottom", we used
// both of them in JVM before 1.5:
// 1. adjust stack pointer first so that it is below "bottom", and then
// touch "bottom"
// 2. mmap() the page in question
//
// Now alternate signal stack is gone, it's harder to use 2. For instance,
// if current sp is already near the lower end of page 101, and we need to
// call mmap() to map page 100, it is possible that part of the mmap() frame
// will be placed in page 100. When page 100 is mapped, it is zero-filled.
// That will destroy the mmap() frame and cause VM to crash.
//
// The following code works by adjusting sp first, then accessing the "bottom"
// page to force a page fault. Linux kernel will then automatically expand the
// stack mapping.
//
// _expand_stack_to() assumes its frame size is less than page size, which
// should always be true if the function is not inlined.
static void NOINLINE _expand_stack_to(address bottom) {
address sp;
size_t size;
volatile char *p;
// Adjust bottom to point to the largest address within the same page, it
// gives us a one-page buffer if alloca() allocates slightly more memory.
bottom = (address)align_down((uintptr_t)bottom, os::vm_page_size());
bottom += os::vm_page_size() - 1;
// sp might be slightly above current stack pointer; if that's the case, we
// will alloca() a little more space than necessary, which is OK. Don't use
// os::current_stack_pointer(), as its result can be slightly below current
// stack pointer, causing us to not alloca enough to reach "bottom".
sp = (address)&sp;
if (sp > bottom) {
size = sp - bottom;
p = (volatile char *)alloca(size);
assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
p[0] = '\0';
}
}
void os::Linux::expand_stack_to(address bottom) {
_expand_stack_to(bottom);
}
bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
assert(t!=NULL, "just checking");
assert(t->osthread()->expanding_stack(), "expand should be set");
if (t->is_in_usable_stack(addr)) {
sigset_t mask_all, old_sigset;
sigfillset(&mask_all);
pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
_expand_stack_to(addr);
pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
return true;
}
return false;
}
//////////////////////////////////////////////////////////////////////////////
// create new thread
// Thread start routine for all newly created threads
static void *thread_native_entry(Thread *thread) {
thread->record_stack_base_and_size();
#ifndef __GLIBC__
// Try to randomize the cache line index of hot stack frames.
// This helps when threads of the same stack traces evict each other's
// cache lines. The threads can be either from the same JVM instance, or
// from different JVM instances. The benefit is especially true for
// processors with hyperthreading technology.
// This code is not needed anymore in glibc because it has MULTI_PAGE_ALIASING
// and we did not see any degradation in performance without `alloca()`.
static int counter = 0;
int pid = os::current_process_id();
int random = ((pid ^ counter++) & 7) * 128;
void *stackmem = alloca(random != 0 ? random : 1); // ensure we allocate > 0
// Ensure the alloca result is used in a way that prevents the compiler from eliding it.
*(char *)stackmem = 1;
#endif
thread->initialize_thread_current();
OSThread* osthread = thread->osthread();
Monitor* sync = osthread->startThread_lock();
osthread->set_thread_id(os::current_thread_id());
if (UseNUMA) {
int lgrp_id = os::numa_get_group_id();
if (lgrp_id != -1) {
thread->set_lgrp_id(lgrp_id);
}
}
// initialize signal mask for this thread
PosixSignals::hotspot_sigmask(thread);
// initialize floating point control register
os::Linux::init_thread_fpu_state();
// handshaking with parent thread
{
MutexLocker ml(sync, Mutex::_no_safepoint_check_flag);
// notify parent thread
osthread->set_state(INITIALIZED);
sync->notify_all();
// wait until os::start_thread()
while (osthread->get_state() == INITIALIZED) {
sync->wait_without_safepoint_check();
}
}
log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
os::current_thread_id(), (uintx) pthread_self());
assert(osthread->pthread_id() != 0, "pthread_id was not set as expected");
// call one more level start routine
thread->call_run();
// Note: at this point the thread object may already have deleted itself.
// Prevent dereferencing it from here on out.
thread = NULL;
log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
os::current_thread_id(), (uintx) pthread_self());
return 0;
}
// On Linux, glibc places static TLS blocks (for __thread variables) on
// the thread stack. This decreases the stack size actually available
// to threads.
//
// For large static TLS sizes, this may cause threads to malfunction due
// to insufficient stack space. This is a well-known issue in glibc:
// http://sourceware.org/bugzilla/show_bug.cgi?id=11787.
//
// As a workaround, we call a private but assumed-stable glibc function,
// __pthread_get_minstack() to obtain the minstack size and derive the
// static TLS size from it. We then increase the user requested stack
// size by this TLS size.
//
// Due to compatibility concerns, this size adjustment is opt-in and
// controlled via AdjustStackSizeForTLS.
typedef size_t (*GetMinStack)(const pthread_attr_t *attr);
GetMinStack _get_minstack_func = NULL;
static void get_minstack_init() {
_get_minstack_func =
(GetMinStack)dlsym(RTLD_DEFAULT, "__pthread_get_minstack");
log_info(os, thread)("Lookup of __pthread_get_minstack %s",
_get_minstack_func == NULL ? "failed" : "succeeded");
}
// Returns the size of the static TLS area glibc puts on thread stacks.
// The value is cached on first use, which occurs when the first thread
// is created during VM initialization.
static size_t get_static_tls_area_size(const pthread_attr_t *attr) {
size_t tls_size = 0;
if (_get_minstack_func != NULL) {
// Obtain the pthread minstack size by calling __pthread_get_minstack.
size_t minstack_size = _get_minstack_func(attr);
// Remove non-TLS area size included in minstack size returned
// by __pthread_get_minstack() to get the static TLS size.
// In glibc before 2.27, minstack size includes guard_size.
// In glibc 2.27 and later, guard_size is automatically added
// to the stack size by pthread_create and is no longer included
// in minstack size. In both cases, the guard_size is taken into
// account, so there is no need to adjust the result for that.
//
// Although __pthread_get_minstack() is a private glibc function,
// it is expected to have a stable behavior across future glibc
// versions while glibc still allocates the static TLS blocks off
// the stack. Following is glibc 2.28 __pthread_get_minstack():
//
// size_t
// __pthread_get_minstack (const pthread_attr_t *attr)
// {
// return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN;
// }
//
//
// The following 'minstack_size > os::vm_page_size() + PTHREAD_STACK_MIN'
// if check is done for precaution.
if (minstack_size > (size_t)os::vm_page_size() + PTHREAD_STACK_MIN) {
tls_size = minstack_size - os::vm_page_size() - PTHREAD_STACK_MIN;
}
}
log_info(os, thread)("Stack size adjustment for TLS is " SIZE_FORMAT,
tls_size);
return tls_size;
}
bool os::create_thread(Thread* thread, ThreadType thr_type,
size_t req_stack_size) {
assert(thread->osthread() == NULL, "caller responsible");
// Allocate the OSThread object
OSThread* osthread = new OSThread();
if (osthread == NULL) {
return false;
}
// set the correct thread state
osthread->set_thread_type(thr_type);
// Initial state is ALLOCATED but not INITIALIZED
osthread->set_state(ALLOCATED);
thread->set_osthread(osthread);
// init thread attributes
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
// Calculate stack size if it's not specified by caller.
size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
// In glibc versions prior to 2.27 the guard size mechanism
// is not implemented properly. The posix standard requires adding
// the size of the guard pages to the stack size, instead Linux
// takes the space out of 'stacksize'. Thus we adapt the requested
// stack_size by the size of the guard pages to mimic proper
// behaviour. However, be careful not to end up with a size
// of zero due to overflow. Don't add the guard page in that case.
size_t guard_size = os::Linux::default_guard_size(thr_type);
// Configure glibc guard page. Must happen before calling
// get_static_tls_area_size(), which uses the guard_size.
pthread_attr_setguardsize(&attr, guard_size);
size_t stack_adjust_size = 0;
if (AdjustStackSizeForTLS) {
// Adjust the stack_size for on-stack TLS - see get_static_tls_area_size().
stack_adjust_size += get_static_tls_area_size(&attr);
} else {
stack_adjust_size += guard_size;
}
stack_adjust_size = align_up(stack_adjust_size, os::vm_page_size());
if (stack_size <= SIZE_MAX - stack_adjust_size) {
stack_size += stack_adjust_size;
}
assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned");
int status = pthread_attr_setstacksize(&attr, stack_size);
if (status != 0) {
// pthread_attr_setstacksize() function can fail
// if the stack size exceeds a system-imposed limit.
assert_status(status == EINVAL, status, "pthread_attr_setstacksize");
log_warning(os, thread)("The %sthread stack size specified is invalid: " SIZE_FORMAT "k",
(thr_type == compiler_thread) ? "compiler " : ((thr_type == java_thread) ? "" : "VM "),
stack_size / K);
thread->set_osthread(NULL);
delete osthread;
return false;
}
ThreadState state;
{
ResourceMark rm;
pthread_t tid;
int ret = 0;
int limit = 3;
do {
ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
} while (ret == EAGAIN && limit-- > 0);
char buf[64];
if (ret == 0) {
log_info(os, thread)("Thread \"%s\" started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
thread->name(), (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
} else {
log_warning(os, thread)("Failed to start thread \"%s\" - pthread_create failed (%s) for attributes: %s.",
thread->name(), os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
// Log some OS information which might explain why creating the thread failed.
log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads());
LogStream st(Log(os, thread)::info());
os::Posix::print_rlimit_info(&st);
os::print_memory_info(&st);
os::Linux::print_proc_sys_info(&st);
os::Linux::print_container_info(&st);
}
pthread_attr_destroy(&attr);
if (ret != 0) {
// Need to clean up stuff we've allocated so far
thread->set_osthread(NULL);
delete osthread;
return false;
}
// Store pthread info into the OSThread
osthread->set_pthread_id(tid);
// Wait until child thread is either initialized or aborted
{
Monitor* sync_with_child = osthread->startThread_lock();
MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
while ((state = osthread->get_state()) == ALLOCATED) {
sync_with_child->wait_without_safepoint_check();
}
}
}
// The thread is returned suspended (in state INITIALIZED),
// and is started higher up in the call chain
assert(state == INITIALIZED, "race condition");
return true;
}
/////////////////////////////////////////////////////////////////////////////
// attach existing thread
// bootstrap the main thread
bool os::create_main_thread(JavaThread* thread) {
assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
return create_attached_thread(thread);
}
bool os::create_attached_thread(JavaThread* thread) {
#ifdef ASSERT
thread->verify_not_published();
#endif
// Allocate the OSThread object
OSThread* osthread = new OSThread();
if (osthread == NULL) {
return false;
}
// Store pthread info into the OSThread
osthread->set_thread_id(os::Linux::gettid());
osthread->set_pthread_id(::pthread_self());
// initialize floating point control register
os::Linux::init_thread_fpu_state();
// Initial thread state is RUNNABLE
osthread->set_state(RUNNABLE);
thread->set_osthread(osthread);
if (UseNUMA) {
int lgrp_id = os::numa_get_group_id();
if (lgrp_id != -1) {
thread->set_lgrp_id(lgrp_id);
}
}
if (os::is_primordial_thread()) {
// If current thread is primordial thread, its stack is mapped on demand,
// see notes about MAP_GROWSDOWN. Here we try to force kernel to map
// the entire stack region to avoid SEGV in stack banging.
// It is also useful to get around the heap-stack-gap problem on SuSE
// kernel (see 4821821 for details). We first expand stack to the top
// of yellow zone, then enable stack yellow zone (order is significant,
// enabling yellow zone first will crash JVM on SuSE Linux), so there
// is no gap between the last two virtual memory regions.
StackOverflow* overflow_state = thread->stack_overflow_state();
address addr = overflow_state->stack_reserved_zone_base();
assert(addr != NULL, "initialization problem?");
assert(overflow_state->stack_available(addr) > 0, "stack guard should not be enabled");
osthread->set_expanding_stack();
os::Linux::manually_expand_stack(thread, addr);
osthread->clear_expanding_stack();
}
// initialize signal mask for this thread
// and save the caller's signal mask
PosixSignals::hotspot_sigmask(thread);
log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT
", stack: " PTR_FORMAT " - " PTR_FORMAT " (" SIZE_FORMAT "k) ).",
os::current_thread_id(), (uintx) pthread_self(),
p2i(thread->stack_base()), p2i(thread->stack_end()), thread->stack_size());
return true;
}
void os::pd_start_thread(Thread* thread) {
OSThread * osthread = thread->osthread();
assert(osthread->get_state() != INITIALIZED, "just checking");
Monitor* sync_with_child = osthread->startThread_lock();
MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
sync_with_child->notify();
}
// Free Linux resources related to the OSThread
void os::free_thread(OSThread* osthread) {
assert(osthread != NULL, "osthread not set");
// We are told to free resources of the argument thread,
// but we can only really operate on the current thread.
assert(Thread::current()->osthread() == osthread,
"os::free_thread but not current thread");
#ifdef ASSERT
sigset_t current;
sigemptyset(¤t);
pthread_sigmask(SIG_SETMASK, NULL, ¤t);
assert(!sigismember(¤t, PosixSignals::SR_signum), "SR signal should not be blocked!");
#endif
// Restore caller's signal mask
sigset_t sigmask = osthread->caller_sigmask();
pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
delete osthread;
}
//////////////////////////////////////////////////////////////////////////////
// primordial thread
// Check if current thread is the primordial thread, similar to Solaris thr_main.
bool os::is_primordial_thread(void) {
if (suppress_primordial_thread_resolution) {
return false;
}
char dummy;
// If called before init complete, thread stack bottom will be null.
// Can be called if fatal error occurs before initialization.
if (os::Linux::initial_thread_stack_bottom() == NULL) return false;
assert(os::Linux::initial_thread_stack_bottom() != NULL &&
os::Linux::initial_thread_stack_size() != 0,
"os::init did not locate primordial thread's stack region");
if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() &&
(address)&dummy < os::Linux::initial_thread_stack_bottom() +
os::Linux::initial_thread_stack_size()) {
return true;
} else {
return false;
}
}
// Find the virtual memory area that contains addr
static bool find_vma(address addr, address* vma_low, address* vma_high) {
FILE *fp = os::fopen("/proc/self/maps", "r");
if (fp) {
address low, high;
while (!feof(fp)) {
if (fscanf(fp, "%p-%p", &low, &high) == 2) {
if (low <= addr && addr < high) {
if (vma_low) *vma_low = low;
if (vma_high) *vma_high = high;
fclose(fp);
return true;
}
}
for (;;) {
int ch = fgetc(fp);
if (ch == EOF || ch == (int)'\n') break;
}
}
fclose(fp);
}
return false;
}
// Locate primordial thread stack. This special handling of primordial thread stack
// is needed because pthread_getattr_np() on most (all?) Linux distros returns
// bogus value for the primordial process thread. While the launcher has created
// the VM in a new thread since JDK 6, we still have to allow for the use of the
// JNI invocation API from a primordial thread.
void os::Linux::capture_initial_stack(size_t max_size) {
// max_size is either 0 (which means accept OS default for thread stacks) or
// a user-specified value known to be at least the minimum needed. If we
// are actually on the primordial thread we can make it appear that we have a
// smaller max_size stack by inserting the guard pages at that location. But we
// cannot do anything to emulate a larger stack than what has been provided by
// the OS or threading library. In fact if we try to use a stack greater than
// what is set by rlimit then we will crash the hosting process.
// Maximum stack size is the easy part, get it from RLIMIT_STACK.
// If this is "unlimited" then it will be a huge value.
struct rlimit rlim;
getrlimit(RLIMIT_STACK, &rlim);
size_t stack_size = rlim.rlim_cur;
// 6308388: a bug in ld.so will relocate its own .data section to the
// lower end of primordial stack; reduce ulimit -s value a little bit
// so we won't install guard page on ld.so's data section.
// But ensure we don't underflow the stack size - allow 1 page spare
if (stack_size >= (size_t)(3 * os::vm_page_size())) {
stack_size -= 2 * os::vm_page_size();
}
// Try to figure out where the stack base (top) is. This is harder.
//
// When an application is started, glibc saves the initial stack pointer in
// a global variable "__libc_stack_end", which is then used by system
// libraries. __libc_stack_end should be pretty close to stack top. The
// variable is available since the very early days. However, because it is
// a private interface, it could disappear in the future.
//
// Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
// to __libc_stack_end, it is very close to stack top, but isn't the real
// stack top. Note that /proc may not exist if VM is running as a chroot
// program, so reading /proc/<pid>/stat could fail. Also the contents of
// /proc/<pid>/stat could change in the future (though unlikely).
//
// We try __libc_stack_end first. If that doesn't work, look for
// /proc/<pid>/stat. If neither of them works, we use current stack pointer
// as a hint, which should work well in most cases.
uintptr_t stack_start;
// try __libc_stack_end first
uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
if (p && *p) {
stack_start = *p;
} else {
// see if we can get the start_stack field from /proc/self/stat
FILE *fp;
int pid;
char state;
int ppid;
int pgrp;
int session;
int nr;
int tpgrp;
unsigned long flags;
unsigned long minflt;
unsigned long cminflt;
unsigned long majflt;
unsigned long cmajflt;
unsigned long utime;
unsigned long stime;
long cutime;
long cstime;
long prio;
long nice;
long junk;
long it_real;
uintptr_t start;
uintptr_t vsize;
intptr_t rss;
uintptr_t rsslim;
uintptr_t scodes;
uintptr_t ecode;
int i;
// Figure what the primordial thread stack base is. Code is inspired
// by email from Hans Boehm. /proc/self/stat begins with current pid,
// followed by command name surrounded by parentheses, state, etc.
char stat[2048];
int statlen;
fp = os::fopen("/proc/self/stat", "r");
if (fp) {
statlen = fread(stat, 1, 2047, fp);
stat[statlen] = '\0';
fclose(fp);
// Skip pid and the command string. Note that we could be dealing with
// weird command names, e.g. user could decide to rename java launcher
// to "java 1.4.2 :)", then the stat file would look like
// 1234 (java 1.4.2 :)) R ... ...
// We don't really need to know the command string, just find the last
// occurrence of ")" and then start parsing from there. See bug 4726580.
char * s = strrchr(stat, ')');
i = 0;
if (s) {
// Skip blank chars
do { s++; } while (s && isspace(*s));
#define _UFM UINTX_FORMAT
#define _DFM INTX_FORMAT
// 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
// 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8
i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM,
&state, // 3 %c
&ppid, // 4 %d
&pgrp, // 5 %d
&session, // 6 %d
&nr, // 7 %d
&tpgrp, // 8 %d
&flags, // 9 %lu
&minflt, // 10 %lu
&cminflt, // 11 %lu
&majflt, // 12 %lu
&cmajflt, // 13 %lu
&utime, // 14 %lu
&stime, // 15 %lu
&cutime, // 16 %ld
&cstime, // 17 %ld
&prio, // 18 %ld
&nice, // 19 %ld
&junk, // 20 %ld
&it_real, // 21 %ld
&start, // 22 UINTX_FORMAT
&vsize, // 23 UINTX_FORMAT
&rss, // 24 INTX_FORMAT
&rsslim, // 25 UINTX_FORMAT
&scodes, // 26 UINTX_FORMAT
&ecode, // 27 UINTX_FORMAT
&stack_start); // 28 UINTX_FORMAT
}
#undef _UFM
#undef _DFM
if (i != 28 - 2) {
assert(false, "Bad conversion from /proc/self/stat");
// product mode - assume we are the primordial thread, good luck in the
// embedded case.
warning("Can't detect primordial thread stack location - bad conversion");
stack_start = (uintptr_t) &rlim;
}
} else {
// For some reason we can't open /proc/self/stat (for example, running on
// FreeBSD with a Linux emulator, or inside chroot), this should work for
// most cases, so don't abort:
warning("Can't detect primordial thread stack location - no /proc/self/stat");
stack_start = (uintptr_t) &rlim;
}
}
// Now we have a pointer (stack_start) very close to the stack top, the
// next thing to do is to figure out the exact location of stack top. We
// can find out the virtual memory area that contains stack_start by
// reading /proc/self/maps, it should be the last vma in /proc/self/maps,
// and its upper limit is the real stack top. (again, this would fail if
// running inside chroot, because /proc may not exist.)
uintptr_t stack_top;
address low, high;
if (find_vma((address)stack_start, &low, &high)) {
// success, "high" is the true stack top. (ignore "low", because initial
// thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
stack_top = (uintptr_t)high;
} else {
// failed, likely because /proc/self/maps does not exist
warning("Can't detect primordial thread stack location - find_vma failed");
// best effort: stack_start is normally within a few pages below the real
// stack top, use it as stack top, and reduce stack size so we won't put
// guard page outside stack.
stack_top = stack_start;
stack_size -= 16 * os::vm_page_size();
}
// stack_top could be partially down the page so align it
stack_top = align_up(stack_top, os::vm_page_size());
// Allowed stack value is minimum of max_size and what we derived from rlimit
if (max_size > 0) {
_initial_thread_stack_size = MIN2(max_size, stack_size);
} else {
// Accept the rlimit max, but if stack is unlimited then it will be huge, so
// clamp it at 8MB as we do on Solaris
_initial_thread_stack_size = MIN2(stack_size, 8*M);
}
_initial_thread_stack_size = align_down(_initial_thread_stack_size, os::vm_page_size());
_initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
if (log_is_enabled(Info, os, thread)) {
// See if we seem to be on primordial process thread
bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) &&
uintptr_t(&rlim) < stack_top;
log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: "
SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT,
primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K,
stack_top, intptr_t(_initial_thread_stack_bottom));
}
}
////////////////////////////////////////////////////////////////////////////////
// time support
double os::elapsedVTime() {
struct rusage usage;
int retval = getrusage(RUSAGE_THREAD, &usage);
if (retval == 0) {
return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000);
} else {
// better than nothing, but not much
return elapsedTime();
}
}
void os::Linux::fast_thread_clock_init() {
if (!UseLinuxPosixThreadCPUClocks) {
return;
}
clockid_t clockid;
struct timespec tp;
int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
(int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
// Switch to using fast clocks for thread cpu time if
// the clock_getres() returns 0 error code.
// Note, that some kernels may support the current thread
// clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
// returned by the pthread_getcpuclockid().
// If the fast Posix clocks are supported then the clock_getres()
// must return at least tp.tv_sec == 0 which means a resolution
// better than 1 sec. This is extra check for reliability.
if (pthread_getcpuclockid_func &&
pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
_supports_fast_thread_cpu_time = true;
_pthread_getcpuclockid = pthread_getcpuclockid_func;
}
}
// thread_id is kernel thread id (similar to Solaris LWP id)
intx os::current_thread_id() { return os::Linux::gettid(); }
int os::current_process_id() {
return ::getpid();
}
// DLL functions
// This must be hard coded because it's the system's temporary
// directory not the java application's temp directory, ala java.io.tmpdir.
const char* os::get_temp_directory() { return "/tmp"; }
// check if addr is inside libjvm.so
bool os::address_is_in_vm(address addr) {
static address libjvm_base_addr;
Dl_info dlinfo;
if (libjvm_base_addr == NULL) {
if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
libjvm_base_addr = (address)dlinfo.dli_fbase;
}
assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
}
if (dladdr((void *)addr, &dlinfo) != 0) {
if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
}
return false;
}
bool os::dll_address_to_function_name(address addr, char *buf,
int buflen, int *offset,
bool demangle) {
// buf is not optional, but offset is optional
assert(buf != NULL, "sanity check");
Dl_info dlinfo;
if (dladdr((void*)addr, &dlinfo) != 0) {
// see if we have a matching symbol
if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
}
if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
return true;
}
// no matching symbol so try for just file info
if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
buf, buflen, offset, dlinfo.dli_fname, demangle)) {
return true;
}
}
}
buf[0] = '\0';
if (offset != NULL) *offset = -1;
return false;
}
bool os::dll_address_to_library_name(address addr, char* buf,
int buflen, int* offset) {
// buf is not optional, but offset is optional
assert(buf != nullptr, "sanity check");
Dl_info dlinfo;
if (dladdr((void*)addr, &dlinfo) != 0) {
if (dlinfo.dli_fname != nullptr) {
jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
}
if (dlinfo.dli_fbase != nullptr && offset != nullptr) {
*offset = addr - (address)dlinfo.dli_fbase;
}
return true;
}
buf[0] = '\0';
if (offset) *offset = -1;
return false;
}
// Remember the stack's state. The Linux dynamic linker will change
// the stack to 'executable' at most once, so we must safepoint only once.
bool os::Linux::_stack_is_executable = false;
// VM operation that loads a library. This is necessary if stack protection
// of the Java stacks can be lost during loading the library. If we
// do not stop the Java threads, they can stack overflow before the stacks
// are protected again.
class VM_LinuxDllLoad: public VM_Operation {
private:
const char *_filename;
char *_ebuf;
int _ebuflen;
void *_lib;
public:
VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
_filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
VMOp_Type type() const { return VMOp_LinuxDllLoad; }
void doit() {
_lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
os::Linux::_stack_is_executable = true;
}
void* loaded_library() { return _lib; }
};
void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
void * result = NULL;
bool load_attempted = false;
log_info(os)("attempting shared library load of %s", filename);
// Check whether the library to load might change execution rights
// of the stack. If they are changed, the protection of the stack
// guard pages will be lost. We need a safepoint to fix this.
//
// See Linux man page execstack(8) for more info.
if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
if (!ElfFile::specifies_noexecstack(filename)) {
if (!is_init_completed()) {
os::Linux::_stack_is_executable = true;
// This is OK - No Java threads have been created yet, and hence no
// stack guard pages to fix.
//
// Dynamic loader will make all stacks executable after
// this function returns, and will not do that again.
assert(Threads::number_of_threads() == 0, "no Java threads should exist yet.");
} else {
warning("You have loaded library %s which might have disabled stack guard. "
"The VM will try to fix the stack guard now.\n"
"It's highly recommended that you fix the library with "
"'execstack -c ', or link it with '-z noexecstack'.",
filename);
JavaThread *jt = JavaThread::current();
if (jt->thread_state() != _thread_in_native) {
// This happens when a compiler thread tries to load a hsdis-<arch>.so file
// that requires ExecStack. Cannot enter safe point. Let's give up.
warning("Unable to fix stack guard. Giving up.");
} else {
if (!LoadExecStackDllInVMThread) {
// This is for the case where the DLL has an static
// constructor function that executes JNI code. We cannot
// load such DLLs in the VMThread.
result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
}
ThreadInVMfromNative tiv(jt);
debug_only(VMNativeEntryWrapper vew;)
VM_LinuxDllLoad op(filename, ebuf, ebuflen);
VMThread::execute(&op);
if (LoadExecStackDllInVMThread) {
result = op.loaded_library();
}
load_attempted = true;
}
}
}
}
if (!load_attempted) {
result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
}
if (result != NULL) {
// Successful loading
return result;
}
Elf32_Ehdr elf_head;
int diag_msg_max_length=ebuflen-strlen(ebuf);
char* diag_msg_buf=ebuf+strlen(ebuf);
if (diag_msg_max_length==0) {
// No more space in ebuf for additional diagnostics message
return NULL;
}
int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
if (file_descriptor < 0) {
// Can't open library, report dlerror() message
return NULL;
}
bool failed_to_read_elf_head=
(sizeof(elf_head)!=
(::read(file_descriptor, &elf_head,sizeof(elf_head))));
::close(file_descriptor);
if (failed_to_read_elf_head) {
// file i/o error - report dlerror() msg
return NULL;
}
if (elf_head.e_ident[EI_DATA] != LITTLE_ENDIAN_ONLY(ELFDATA2LSB) BIG_ENDIAN_ONLY(ELFDATA2MSB)) {
// handle invalid/out of range endianness values
if (elf_head.e_ident[EI_DATA] == 0 || elf_head.e_ident[EI_DATA] > 2) {
return NULL;
}
#if defined(VM_LITTLE_ENDIAN)
// VM is LE, shared object BE
elf_head.e_machine = be16toh(elf_head.e_machine);
#else
// VM is BE, shared object LE
elf_head.e_machine = le16toh(elf_head.e_machine);
#endif
}
typedef struct {
Elf32_Half code; // Actual value as defined in elf.h
Elf32_Half compat_class; // Compatibility of archs at VM's sense
unsigned char elf_class; // 32 or 64 bit
unsigned char endianness; // MSB or LSB
char* name; // String representation
} arch_t;
#ifndef EM_AARCH64
#define EM_AARCH64 183 /* ARM AARCH64 */
#endif
#ifndef EM_RISCV
#define EM_RISCV 243 /* RISC-V */
#endif
#ifndef EM_LOONGARCH
#define EM_LOONGARCH 258 /* LoongArch */
#endif
static const arch_t arch_array[]={
{EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
{EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
{EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
{EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
{EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
{EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
{EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
{EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
#if defined(VM_LITTLE_ENDIAN)
{EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"},
{EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"},
#else
{EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
{EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"},
#endif
{EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
// we only support 64 bit z architecture
{EM_S390, EM_S390, ELFCLASS64, ELFDATA2MSB, (char*)"IBM System/390"},
{EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
{EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
{EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
{EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
{EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
{EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
#ifdef _LP64
{EM_RISCV, EM_RISCV, ELFCLASS64, ELFDATA2LSB, (char*)"RISCV64"},
#else
{EM_RISCV, EM_RISCV, ELFCLASS32, ELFDATA2LSB, (char*)"RISCV32"},
#endif
{EM_LOONGARCH, EM_LOONGARCH, ELFCLASS64, ELFDATA2LSB, (char*)"LoongArch"},
};
#if (defined IA32)
static Elf32_Half running_arch_code=EM_386;
#elif (defined AMD64) || (defined X32)
static Elf32_Half running_arch_code=EM_X86_64;
#elif (defined IA64)
static Elf32_Half running_arch_code=EM_IA_64;
#elif (defined __sparc) && (defined _LP64)
static Elf32_Half running_arch_code=EM_SPARCV9;
#elif (defined __sparc) && (!defined _LP64)
static Elf32_Half running_arch_code=EM_SPARC;
#elif (defined __powerpc64__)
static Elf32_Half running_arch_code=EM_PPC64;
#elif (defined __powerpc__)
static Elf32_Half running_arch_code=EM_PPC;
#elif (defined AARCH64)
static Elf32_Half running_arch_code=EM_AARCH64;
#elif (defined ARM)
static Elf32_Half running_arch_code=EM_ARM;
#elif (defined S390)
static Elf32_Half running_arch_code=EM_S390;
#elif (defined ALPHA)
static Elf32_Half running_arch_code=EM_ALPHA;
#elif (defined MIPSEL)
static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
#elif (defined PARISC)
static Elf32_Half running_arch_code=EM_PARISC;
#elif (defined MIPS)
static Elf32_Half running_arch_code=EM_MIPS;
#elif (defined M68K)
static Elf32_Half running_arch_code=EM_68K;
#elif (defined SH)
static Elf32_Half running_arch_code=EM_SH;
#elif (defined RISCV)
static Elf32_Half running_arch_code=EM_RISCV;
#elif (defined LOONGARCH)
static Elf32_Half running_arch_code=EM_LOONGARCH;
#else
#error Method os::dll_load requires that one of following is defined:\
AARCH64, ALPHA, ARM, AMD64, IA32, IA64, LOONGARCH, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, RISCV, S390, SH, __sparc
#endif
// Identify compatibility class for VM's architecture and library's architecture
// Obtain string descriptions for architectures
arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
int running_arch_index=-1;
for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
if (running_arch_code == arch_array[i].code) {
running_arch_index = i;
}
if (lib_arch.code == arch_array[i].code) {
lib_arch.compat_class = arch_array[i].compat_class;
lib_arch.name = arch_array[i].name;
}
}
assert(running_arch_index != -1,
"Didn't find running architecture code (running_arch_code) in arch_array");
if (running_arch_index == -1) {
// Even though running architecture detection failed
// we may still continue with reporting dlerror() message
return NULL;
}
if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
if (lib_arch.name != NULL) {
::snprintf(diag_msg_buf, diag_msg_max_length-1,
" (Possible cause: can't load %s .so on a %s platform)",
lib_arch.name, arch_array[running_arch_index].name);
} else {
::snprintf(diag_msg_buf, diag_msg_max_length-1,
" (Possible cause: can't load this .so (machine code=0x%x) on a %s platform)",
lib_arch.code, arch_array[running_arch_index].name);
}
return NULL;
}
if (lib_arch.endianness != arch_array[running_arch_index].endianness) {
::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: endianness mismatch)");
return NULL;
}
// ELF file class/capacity : 0 - invalid, 1 - 32bit, 2 - 64bit
if (lib_arch.elf_class > 2 || lib_arch.elf_class < 1) {
::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: invalid ELF file class)");
return NULL;
}
if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
::snprintf(diag_msg_buf, diag_msg_max_length-1,
" (Possible cause: architecture word width mismatch, can't load %d-bit .so on a %d-bit platform)",
(int) lib_arch.elf_class * 32, arch_array[running_arch_index].elf_class * 32);
return NULL;
}
return NULL;
}
void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
int ebuflen) {
void * result = ::dlopen(filename, RTLD_LAZY);
if (result == NULL) {
const char* error_report = ::dlerror();
if (error_report == NULL) {
error_report = "dlerror returned no error description";
}
if (ebuf != NULL && ebuflen > 0) {
::strncpy(ebuf, error_report, ebuflen-1);
ebuf[ebuflen-1]='\0';
}
Events::log_dll_message(NULL, "Loading shared library %s failed, %s", filename, error_report);
log_info(os)("shared library load of %s failed, %s", filename, error_report);
} else {
Events::log_dll_message(NULL, "Loaded shared library %s", filename);
log_info(os)("shared library load of %s was successful", filename);
}
return result;
}
void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
int ebuflen) {
void * result = NULL;
if (LoadExecStackDllInVMThread) {
result = dlopen_helper(filename, ebuf, ebuflen);
}
// Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
// library that requires an executable stack, or which does not have this
// stack attribute set, dlopen changes the stack attribute to executable. The
// read protection of the guard pages gets lost.
//
// Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
// may have been queued at the same time.
if (!_stack_is_executable) {
for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
StackOverflow* overflow_state = jt->stack_overflow_state();
if (!overflow_state->stack_guard_zone_unused() && // Stack not yet fully initialized
overflow_state->stack_guards_enabled()) { // No pending stack overflow exceptions
if (!os::guard_memory((char *)jt->stack_end(), StackOverflow::stack_guard_zone_size())) {
warning("Attempt to reguard stack yellow zone failed.");
}
}
}
}
return result;
}
const char* os::Linux::dll_path(void* lib) {
struct link_map *lmap;
const char* l_path = NULL;
assert(lib != NULL, "dll_path parameter must not be NULL");
int res_dli = ::dlinfo(lib, RTLD_DI_LINKMAP, &lmap);
if (res_dli == 0) {
l_path = lmap->l_name;
}
return l_path;
}
static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) {
int fd = ::open(filename, O_RDONLY);
if (fd == -1) {
return false;
}
if (hdr != NULL) {
st->print_cr("%s", hdr);
}
char buf[33];
int bytes;
buf[32] = '\0';
while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
st->print_raw(buf, bytes);
}
::close(fd);
return true;
}
static void _print_ascii_file_h(const char* header, const char* filename, outputStream* st, bool same_line = true) {
st->print("%s:%c", header, same_line ? ' ' : '\n');
if (!_print_ascii_file(filename, st)) {
st->print_cr("");
}
}
void os::print_dll_info(outputStream *st) {
st->print_cr("Dynamic libraries:");
char fname[32];
pid_t pid = os::Linux::gettid();
jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
if (!_print_ascii_file(fname, st)) {
st->print_cr("Can not get library information for pid = %d", pid);
}
}
struct loaded_modules_info_param {
os::LoadedModulesCallbackFunc callback;
void *param;
};
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