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/*
* Copyright (c) 1999, 2022, 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 "classfile/classLoader.hpp"
#include "jvm.h"
#include "jvmtifiles/jvmti.h"
#include "logging/log.hpp"
#include "memory/allocation.inline.hpp"
#include "os_posix.inline.hpp"
#include "runtime/globals_extension.hpp"
#include "runtime/osThread.hpp"
#include "runtime/frame.inline.hpp"
#include "runtime/interfaceSupport.inline.hpp"
#include "runtime/sharedRuntime.hpp"
#include "services/attachListener.hpp"
#include "services/memTracker.hpp"
#include "runtime/arguments.hpp"
#include "runtime/atomic.hpp"
#include "runtime/java.hpp"
#include "runtime/orderAccess.hpp"
#include "runtime/park.hpp"
#include "runtime/perfMemory.hpp"
#include "utilities/align.hpp"
#include "utilities/defaultStream.hpp"
#include "utilities/events.hpp"
#include "utilities/formatBuffer.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/macros.hpp"
#include "utilities/vmError.hpp"
#ifdef LINUX
#include "os_linux.hpp"
#endif
#include <dirent.h>
#include <dlfcn.h>
#include <grp.h>
#include <locale.h>
#include <netdb.h>
#include <pwd.h>
#include <pthread.h>
#include <signal.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <spawn.h>
#include <sys/time.h>
#include <sys/times.h>
#include <sys/types.h>
#include <sys/utsname.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#include <utmpx.h>
#ifdef __APPLE__
#include <crt_externs.h>
#endif
#define ROOT_UID 0
#ifndef MAP_ANONYMOUS
#define MAP_ANONYMOUS MAP_ANON
#endif
#define check_with_errno(check_type, cond, msg) \
do { \
int err = errno; \
check_type(cond, "%s; error='%s' (errno=%s)", msg, os::strerror(err), \
os::errno_name(err)); \
} while (false)
#define assert_with_errno(cond, msg) check_with_errno(assert, cond, msg)
#define guarantee_with_errno(cond, msg) check_with_errno(guarantee, cond, msg)
static jlong initial_time_count = 0;
static int clock_tics_per_sec = 100;
// Platform minimum stack allowed
size_t os::_os_min_stack_allowed = PTHREAD_STACK_MIN;
// Check core dump limit and report possible place where core can be found
void os::check_dump_limit(char* buffer, size_t bufferSize) {
if (!FLAG_IS_DEFAULT(CreateCoredumpOnCrash) && !CreateCoredumpOnCrash) {
jio_snprintf(buffer, bufferSize, "CreateCoredumpOnCrash is disabled from command line");
VMError::record_coredump_status(buffer, false);
return;
}
int n;
struct rlimit rlim;
bool success;
char core_path[PATH_MAX];
n = get_core_path(core_path, PATH_MAX);
if (n <= 0) {
jio_snprintf(buffer, bufferSize, "core.%d (may not exist)", current_process_id());
success = true;
#ifdef LINUX
} else if (core_path[0] == '"') { // redirect to user process
jio_snprintf(buffer, bufferSize, "Core dumps may be processed with %s", core_path);
success = true;
#endif
} else if (getrlimit(RLIMIT_CORE, &rlim) != 0) {
jio_snprintf(buffer, bufferSize, "%s (may not exist)", core_path);
success = true;
} else {
switch(rlim.rlim_cur) {
case RLIM_INFINITY:
jio_snprintf(buffer, bufferSize, "%s", core_path);
success = true;
break;
case 0:
jio_snprintf(buffer, bufferSize, "Core dumps have been disabled. To enable core dumping, try \"ulimit -c unlimited\" before starting Java again");
success = false;
break;
default:
jio_snprintf(buffer, bufferSize, "%s (max size " UINT64_FORMAT " k). To ensure a full core dump, try \"ulimit -c unlimited\" before starting Java again", core_path, uint64_t(rlim.rlim_cur) / K);
success = true;
break;
}
}
VMError::record_coredump_status(buffer, success);
}
int os::get_native_stack(address* stack, int frames, int toSkip) {
int frame_idx = 0;
int num_of_frames; // number of frames captured
frame fr = os::current_frame();
while (fr.pc() && frame_idx < frames) {
if (toSkip > 0) {
toSkip --;
} else {
stack[frame_idx ++] = fr.pc();
}
if (fr.fp() == NULL || fr.cb() != NULL ||
fr.sender_pc() == NULL || os::is_first_C_frame(&fr)) break;
if (fr.sender_pc() && !os::is_first_C_frame(&fr)) {
fr = os::get_sender_for_C_frame(&fr);
} else {
break;
}
}
num_of_frames = frame_idx;
for (; frame_idx < frames; frame_idx ++) {
stack[frame_idx] = NULL;
}
return num_of_frames;
}
int os::get_last_error() {
return errno;
}
size_t os::lasterror(char *buf, size_t len) {
if (errno == 0) return 0;
const char *s = os::strerror(errno);
size_t n = ::strlen(s);
if (n >= len) {
n = len - 1;
}
::strncpy(buf, s, n);
buf[n] = '\0';
return n;
}
// Return true if user is running as root.
bool os::have_special_privileges() {
static bool privileges = (getuid() != geteuid()) || (getgid() != getegid());
return privileges;
}
void os::wait_for_keypress_at_exit(void) {
// don't do anything on posix platforms
return;
}
int os::create_file_for_heap(const char* dir) {
int fd;
#if defined(LINUX) && defined(O_TMPFILE)
char* native_dir = os::strdup(dir);
if (native_dir == NULL) {
vm_exit_during_initialization(err_msg("strdup failed during creation of backing file for heap (%s)", os::strerror(errno)));
return -1;
}
os::native_path(native_dir);
fd = os::open(dir, O_TMPFILE | O_RDWR, S_IRUSR | S_IWUSR);
os::free(native_dir);
if (fd == -1)
#endif
{
const char name_template[] = "/jvmheap.XXXXXX";
size_t fullname_len = strlen(dir) + strlen(name_template);
char *fullname = (char*)os::malloc(fullname_len + 1, mtInternal);
if (fullname == NULL) {
vm_exit_during_initialization(err_msg("Malloc failed during creation of backing file for heap (%s)", os::strerror(errno)));
return -1;
}
int n = snprintf(fullname, fullname_len + 1, "%s%s", dir, name_template);
assert((size_t)n == fullname_len, "Unexpected number of characters in string");
os::native_path(fullname);
// create a new file.
fd = mkstemp(fullname);
if (fd < 0) {
warning("Could not create file for heap with template %s", fullname);
os::free(fullname);
return -1;
} else {
// delete the name from the filesystem. When 'fd' is closed, the file (and space) will be deleted.
int ret = unlink(fullname);
assert_with_errno(ret == 0, "unlink returned error");
}
os::free(fullname);
}
return fd;
}
// Is a (classpath) directory empty?
bool os::dir_is_empty(const char* path) {
DIR *dir = NULL;
struct dirent *ptr;
dir = ::opendir(path);
if (dir == NULL) return true;
// Scan the directory
bool result = true;
while (result && (ptr = ::readdir(dir)) != NULL) {
if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
result = false;
}
}
::closedir(dir);
return result;
}
static char* reserve_mmapped_memory(size_t bytes, char* requested_addr) {
char * addr;
int flags = MAP_PRIVATE NOT_AIX( | MAP_NORESERVE ) | MAP_ANONYMOUS;
if (requested_addr != NULL) {
assert((uintptr_t)requested_addr % os::vm_page_size() == 0, "Requested address should be aligned to OS page size");
flags |= MAP_FIXED;
}
// Map reserved/uncommitted pages PROT_NONE so we fail early if we
// touch an uncommitted page. Otherwise, the read/write might
// succeed if we have enough swap space to back the physical page.
addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
flags, -1, 0);
if (addr != MAP_FAILED) {
MemTracker::record_virtual_memory_reserve((address)addr, bytes, CALLER_PC);
return addr;
}
return NULL;
}
static int util_posix_fallocate(int fd, off_t offset, off_t len) {
#ifdef __APPLE__
fstore_t store = { F_ALLOCATECONTIG, F_PEOFPOSMODE, 0, len };
// First we try to get a continuous chunk of disk space
int ret = fcntl(fd, F_PREALLOCATE, &store);
if (ret == -1) {
// Maybe we are too fragmented, try to allocate non-continuous range
store.fst_flags = F_ALLOCATEALL;
ret = fcntl(fd, F_PREALLOCATE, &store);
}
if(ret != -1) {
return ftruncate(fd, len);
}
return -1;
#else
return posix_fallocate(fd, offset, len);
#endif
}
// Map the given address range to the provided file descriptor.
char* os::map_memory_to_file(char* base, size_t size, int fd) {
assert(fd != -1, "File descriptor is not valid");
// allocate space for the file
int ret = util_posix_fallocate(fd, 0, (off_t)size);
if (ret != 0) {
vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory. error(%d)", ret));
return NULL;
}
int prot = PROT_READ | PROT_WRITE;
int flags = MAP_SHARED;
if (base != NULL) {
flags |= MAP_FIXED;
}
char* addr = (char*)mmap(base, size, prot, flags, fd, 0);
if (addr == MAP_FAILED) {
warning("Failed mmap to file. (%s)", os::strerror(errno));
return NULL;
}
if (base != NULL && addr != base) {
if (!os::release_memory(addr, size)) {
warning("Could not release memory on unsuccessful file mapping");
}
return NULL;
}
return addr;
}
char* os::replace_existing_mapping_with_file_mapping(char* base, size_t size, int fd) {
assert(fd != -1, "File descriptor is not valid");
assert(base != NULL, "Base cannot be NULL");
return map_memory_to_file(base, size, fd);
}
static size_t calculate_aligned_extra_size(size_t size, size_t alignment) {
assert((alignment & (os::vm_allocation_granularity() - 1)) == 0,
"Alignment must be a multiple of allocation granularity (page size)");
assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned");
size_t extra_size = size + alignment;
assert(extra_size >= size, "overflow, size is too large to allow alignment");
return extra_size;
}
// After a bigger chunk was mapped, unmaps start and end parts to get the requested alignment.
static char* chop_extra_memory(size_t size, size_t alignment, char* extra_base, size_t extra_size) {
// Do manual alignment
char* aligned_base = align_up(extra_base, alignment);
// [ | | ]
// ^ extra_base
// ^ extra_base + begin_offset == aligned_base
// extra_base + begin_offset + size ^
// extra_base + extra_size ^
// |<>| == begin_offset
// end_offset == |<>|
size_t begin_offset = aligned_base - extra_base;
size_t end_offset = (extra_base + extra_size) - (aligned_base + size);
if (begin_offset > 0) {
os::release_memory(extra_base, begin_offset);
}
if (end_offset > 0) {
os::release_memory(extra_base + begin_offset + size, end_offset);
}
return aligned_base;
}
// Multiple threads can race in this code, and can remap over each other with MAP_FIXED,
// so on posix, unmap the section at the start and at the end of the chunk that we mapped
// rather than unmapping and remapping the whole chunk to get requested alignment.
char* os::reserve_memory_aligned(size_t size, size_t alignment, bool exec) {
size_t extra_size = calculate_aligned_extra_size(size, alignment);
char* extra_base = os::reserve_memory(extra_size, exec);
if (extra_base == NULL) {
return NULL;
}
return chop_extra_memory(size, alignment, extra_base, extra_size);
}
char* os::map_memory_to_file_aligned(size_t size, size_t alignment, int file_desc) {
size_t extra_size = calculate_aligned_extra_size(size, alignment);
// For file mapping, we do not call os:map_memory_to_file(size,fd) since:
// - we later chop away parts of the mapping using os::release_memory and that could fail if the
// original mmap call had been tied to an fd.
// - The memory API os::reserve_memory uses is an implementation detail. It may (and usually is)
// mmap but it also may System V shared memory which cannot be uncommitted as a whole, so
// chopping off and unmapping excess bits back and front (see below) would not work.
char* extra_base = reserve_mmapped_memory(extra_size, NULL);
if (extra_base == NULL) {
return NULL;
}
char* aligned_base = chop_extra_memory(size, alignment, extra_base, extra_size);
// After we have an aligned address, we can replace anonymous mapping with file mapping
if (replace_existing_mapping_with_file_mapping(aligned_base, size, file_desc) == NULL) {
vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
}
MemTracker::record_virtual_memory_commit((address)aligned_base, size, CALLER_PC);
return aligned_base;
}
int os::vsnprintf(char* buf, size_t len, const char* fmt, va_list args) {
// All supported POSIX platforms provide C99 semantics.
ALLOW_C_FUNCTION(::vsnprintf, int result = ::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;
}
int os::get_fileno(FILE* fp) {
return NOT_AIX(::)fileno(fp);
}
struct tm* os::gmtime_pd(const time_t* clock, struct tm* res) {
return gmtime_r(clock, res);
}
void os::Posix::print_load_average(outputStream* st) {
st->print("load average: ");
double loadavg[3];
int res = os::loadavg(loadavg, 3);
if (res != -1) {
st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
} else {
st->print(" Unavailable");
}
st->cr();
}
// boot/uptime information;
// unfortunately it does not work on macOS and Linux because the utx chain has no entry
// for reboot at least on my test machines
void os::Posix::print_uptime_info(outputStream* st) {
int bootsec = -1;
int currsec = time(NULL);
struct utmpx* ent;
setutxent();
while ((ent = getutxent())) {
if (!strcmp("system boot", ent->ut_line)) {
bootsec = ent->ut_tv.tv_sec;
break;
}
}
if (bootsec != -1) {
os::print_dhm(st, "OS uptime:", (long) (currsec-bootsec));
}
}
static void print_rlimit(outputStream* st, const char* msg,
int resource, bool output_k = false) {
struct rlimit rlim;
st->print(" %s ", msg);
int res = getrlimit(resource, &rlim);
if (res == -1) {
st->print("could not obtain value");
} else {
// soft limit
if (rlim.rlim_cur == RLIM_INFINITY) { st->print("infinity"); }
else {
if (output_k) { st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / K); }
else { st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur)); }
}
// hard limit
st->print("/");
if (rlim.rlim_max == RLIM_INFINITY) { st->print("infinity"); }
else {
if (output_k) { st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_max) / K); }
else { st->print(UINT64_FORMAT, uint64_t(rlim.rlim_max)); }
}
}
}
void os::Posix::print_rlimit_info(outputStream* st) {
st->print("rlimit (soft/hard):");
print_rlimit(st, "STACK", RLIMIT_STACK, true);
print_rlimit(st, ", CORE", RLIMIT_CORE, true);
#if defined(AIX)
st->print(", NPROC ");
st->print("%d", sysconf(_SC_CHILD_MAX));
print_rlimit(st, ", THREADS", RLIMIT_THREADS);
#else
print_rlimit(st, ", NPROC", RLIMIT_NPROC);
#endif
print_rlimit(st, ", NOFILE", RLIMIT_NOFILE);
print_rlimit(st, ", AS", RLIMIT_AS, true);
print_rlimit(st, ", CPU", RLIMIT_CPU);
print_rlimit(st, ", DATA", RLIMIT_DATA, true);
// maximum size of files that the process may create
print_rlimit(st, ", FSIZE", RLIMIT_FSIZE, true);
#if defined(LINUX) || defined(__APPLE__)
// maximum number of bytes of memory that may be locked into RAM
// (rounded down to the nearest multiple of system pagesize)
print_rlimit(st, ", MEMLOCK", RLIMIT_MEMLOCK, true);
#endif
// MacOS; The maximum size (in bytes) to which a process's resident set size may grow.
#if defined(__APPLE__)
print_rlimit(st, ", RSS", RLIMIT_RSS, true);
#endif
st->cr();
}
void os::Posix::print_uname_info(outputStream* st) {
// kernel
st->print("uname: ");
struct utsname name;
uname(&name);
st->print("%s ", name.sysname);
#ifdef ASSERT
st->print("%s ", name.nodename);
#endif
st->print("%s ", name.release);
st->print("%s ", name.version);
st->print("%s", name.machine);
st->cr();
}
void os::Posix::print_umask(outputStream* st, mode_t umsk) {
st->print((umsk & S_IRUSR) ? "r" : "-");
st->print((umsk & S_IWUSR) ? "w" : "-");
st->print((umsk & S_IXUSR) ? "x" : "-");
st->print((umsk & S_IRGRP) ? "r" : "-");
st->print((umsk & S_IWGRP) ? "w" : "-");
st->print((umsk & S_IXGRP) ? "x" : "-");
st->print((umsk & S_IROTH) ? "r" : "-");
st->print((umsk & S_IWOTH) ? "w" : "-");
st->print((umsk & S_IXOTH) ? "x" : "-");
}
void os::print_user_info(outputStream* st) {
unsigned id = (unsigned) ::getuid();
st->print("uid : %u ", id);
id = (unsigned) ::geteuid();
st->print("euid : %u ", id);
id = (unsigned) ::getgid();
st->print("gid : %u ", id);
id = (unsigned) ::getegid();
st->print_cr("egid : %u", id);
st->cr();
mode_t umsk = ::umask(0);
::umask(umsk);
st->print("umask: %04o (", (unsigned) umsk);
os::Posix::print_umask(st, umsk);
st->print_cr(")");
st->cr();
}
// Print all active locale categories, one line each
void os::print_active_locale(outputStream* st) {
st->print_cr("Active Locale:");
// Posix is quiet about how exactly LC_ALL is implemented.
// Just print it out too, in case LC_ALL is held separately
// from the individual categories.
#define LOCALE_CAT_DO(f) \
f(LC_ALL) \
f(LC_COLLATE) \
f(LC_CTYPE) \
f(LC_MESSAGES) \
f(LC_MONETARY) \
f(LC_NUMERIC) \
f(LC_TIME)
#define XX(cat) { cat, #cat },
const struct { int c; const char* name; } categories[] = {
LOCALE_CAT_DO(XX)
{ -1, NULL }
};
#undef XX
#undef LOCALE_CAT_DO
for (int i = 0; categories[i].c != -1; i ++) {
const char* locale = setlocale(categories[i].c, NULL);
st->print_cr("%s=%s", categories[i].name,
((locale != NULL) ? locale : ""));
}
}
void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
// no prefix required
}
void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
// no suffix required
}
bool os::get_host_name(char* buf, size_t buflen) {
struct utsname name;
uname(&name);
jio_snprintf(buf, buflen, "%s", name.nodename);
return true;
}
#ifndef _LP64
// Helper, on 32bit, for os::has_allocatable_memory_limit
static bool is_allocatable(size_t s) {
if (s < 2 * G) {
return true;
}
// Use raw anonymous mmap here; no need to go through any
// of our reservation layers. We will unmap right away.
void* p = ::mmap(NULL, s, PROT_NONE,
MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS, -1, 0);
if (p == MAP_FAILED) {
return false;
} else {
::munmap(p, s);
return true;
}
}
#endif // !_LP64
bool os::has_allocatable_memory_limit(size_t* limit) {
struct rlimit rlim;
int getrlimit_res = getrlimit(RLIMIT_AS, &rlim);
// if there was an error when calling getrlimit, assume that there is no limitation
// on virtual memory.
bool result;
if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) {
result = false;
} else {
*limit = (size_t)rlim.rlim_cur;
result = true;
}
#ifdef _LP64
return result;
#else
// arbitrary virtual space limit for 32 bit Unices found by testing. If
// getrlimit above returned a limit, bound it with this limit. Otherwise
// directly use it.
const size_t max_virtual_limit = 3800*M;
if (result) {
*limit = MIN2(*limit, max_virtual_limit);
} else {
*limit = max_virtual_limit;
}
// bound by actually allocatable memory. The algorithm uses two bounds, an
// upper and a lower limit. The upper limit is the current highest amount of
// memory that could not be allocated, the lower limit is the current highest
// amount of memory that could be allocated.
// The algorithm iteratively refines the result by halving the difference
// between these limits, updating either the upper limit (if that value could
// not be allocated) or the lower limit (if the that value could be allocated)
// until the difference between these limits is "small".
// the minimum amount of memory we care about allocating.
const size_t min_allocation_size = M;
size_t upper_limit = *limit;
// first check a few trivial cases
if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) {
*limit = upper_limit;
} else if (!is_allocatable(min_allocation_size)) {
// we found that not even min_allocation_size is allocatable. Return it
// anyway. There is no point to search for a better value any more.
*limit = min_allocation_size;
} else {
// perform the binary search.
size_t lower_limit = min_allocation_size;
while ((upper_limit - lower_limit) > min_allocation_size) {
size_t temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit;
temp_limit = align_down(temp_limit, min_allocation_size);
if (is_allocatable(temp_limit)) {
lower_limit = temp_limit;
} else {
upper_limit = temp_limit;
}
}
*limit = lower_limit;
}
return true;
#endif
}
void* os::get_default_process_handle() {
#ifdef __APPLE__
// MacOS X needs to use RTLD_FIRST instead of RTLD_LAZY
// to avoid finding unexpected symbols on second (or later)
// loads of a library.
return (void*)::dlopen(NULL, RTLD_FIRST);
#else
return (void*)::dlopen(NULL, RTLD_LAZY);
#endif
}
void* os::dll_lookup(void* handle, const char* name) {
return dlsym(handle, name);
}
void os::dll_unload(void *lib) {
// os::Linux::dll_path returns a pointer to a string that is owned by the dynamic loader. Upon
// calling dlclose the dynamic loader may free the memory containing the string, thus we need to
// copy the string to be able to reference it after dlclose.
const char* l_path = NULL;
#ifdef LINUX
char* l_pathdup = NULL;
l_path = os::Linux::dll_path(lib);
if (l_path != NULL) {
l_path = l_pathdup = os::strdup(l_path);
}
#endif // LINUX
if (l_path == NULL) {
l_path = "";
}
int res = ::dlclose(lib);
if (res == 0) {
Events::log_dll_message(NULL, "Unloaded shared library \"%s\" [" INTPTR_FORMAT "]",
l_path, p2i(lib));
log_info(os)("Unloaded shared library \"%s\" [" INTPTR_FORMAT "]", l_path, p2i(lib));
} else {
const char* error_report = ::dlerror();
if (error_report == NULL) {
error_report = "dlerror returned no error description";
}
Events::log_dll_message(NULL, "Attempt to unload shared library \"%s\" [" INTPTR_FORMAT "] failed, %s",
l_path, p2i(lib), error_report);
log_info(os)("Attempt to unload shared library \"%s\" [" INTPTR_FORMAT "] failed, %s",
l_path, p2i(lib), error_report);
}
LINUX_ONLY(os::free(l_pathdup));
}
jlong os::lseek(int fd, jlong offset, int whence) {
return (jlong) BSD_ONLY(::lseek) NOT_BSD(::lseek64)(fd, offset, whence);
}
int os::ftruncate(int fd, jlong length) {
return BSD_ONLY(::ftruncate) NOT_BSD(::ftruncate64)(fd, length);
}
const char* os::get_current_directory(char *buf, size_t buflen) {
return getcwd(buf, buflen);
}
FILE* os::fdopen(int fd, const char* mode) {
return ::fdopen(fd, mode);
}
ssize_t os::write(int fd, const void *buf, unsigned int nBytes) {
ssize_t res;
RESTARTABLE(::write(fd, buf, (size_t) nBytes), res);
return res;
}
ssize_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
return ::pread(fd, buf, nBytes, offset);
}
void os::flockfile(FILE* fp) {
::flockfile(fp);
}
void os::funlockfile(FILE* fp) {
::funlockfile(fp);
}
DIR* os::opendir(const char* dirname) {
assert(dirname != NULL, "just checking");
return ::opendir(dirname);
}
struct dirent* os::readdir(DIR* dirp) {
assert(dirp != NULL, "just checking");
return ::readdir(dirp);
}
int os::closedir(DIR *dirp) {
assert(dirp != NULL, "just checking");
return ::closedir(dirp);
}
int os::socket_close(int fd) {
return ::close(fd);
}
int os::recv(int fd, char* buf, size_t nBytes, uint flags) {
RESTARTABLE_RETURN_INT(::recv(fd, buf, nBytes, flags));
}
int os::send(int fd, char* buf, size_t nBytes, uint flags) {
RESTARTABLE_RETURN_INT(::send(fd, buf, nBytes, flags));
}
int os::raw_send(int fd, char* buf, size_t nBytes, uint flags) {
return os::send(fd, buf, nBytes, flags);
}
int os::connect(int fd, struct sockaddr* him, socklen_t len) {
RESTARTABLE_RETURN_INT(::connect(fd, him, len));
}
struct hostent* os::get_host_by_name(char* name) {
return ::gethostbyname(name);
}
void os::exit(int num) {
ALLOW_C_FUNCTION(::exit, ::exit(num);)
}
void os::_exit(int num) {
ALLOW_C_FUNCTION(::_exit, ::_exit(num);)
}
// 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 "/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;
size_t name_len;
size_t prefix_len = strlen(JNI_LIB_PREFIX);
size_t suffix_len = strlen(JNI_LIB_SUFFIX);
const char *start;
if (lib_name != NULL) {
name_len = strlen(lib_name);
if (is_absolute_path) {
// Need to strip path, prefix and suffix
if ((start = strrchr(lib_name, *os::file_separator())) != NULL) {
lib_name = ++start;
}
if (strlen(lib_name) <= (prefix_len + suffix_len)) {
return NULL;
}
lib_name += prefix_len;
name_len = strlen(lib_name) - suffix_len;
}
}
len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2;
agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread);
if (agent_entry_name == NULL) {
return NULL;
}
strcpy(agent_entry_name, sym_name);
if (lib_name != NULL) {
strcat(agent_entry_name, "_");
strncat(agent_entry_name, lib_name, name_len);
}
return agent_entry_name;
}
// Sleep forever; naked call to OS-specific sleep; use with CAUTION
void os::infinite_sleep() {
while (true) { // sleep forever ...
::sleep(100); // ... 100 seconds at a time
}
}
void os::naked_short_nanosleep(jlong ns) {
struct timespec req;
assert(ns > -1 && ns < NANOUNITS, "Un-interruptable sleep, short time use only");
req.tv_sec = 0;
req.tv_nsec = ns;
::nanosleep(&req, NULL);
return;
}
void os::naked_short_sleep(jlong ms) {
assert(ms < MILLIUNITS, "Un-interruptable sleep, short time use only");
os::naked_short_nanosleep(millis_to_nanos(ms));
return;
}
char* os::Posix::describe_pthread_attr(char* buf, size_t buflen, const pthread_attr_t* attr) {
size_t stack_size = 0;
size_t guard_size = 0;
int detachstate = 0;
pthread_attr_getstacksize(attr, &stack_size);
pthread_attr_getguardsize(attr, &guard_size);
// Work around linux NPTL implementation error, see also os::create_thread() in os_linux.cpp.
LINUX_ONLY(stack_size -= guard_size);
pthread_attr_getdetachstate(attr, &detachstate);
jio_snprintf(buf, buflen, "stacksize: " SIZE_FORMAT "k, guardsize: " SIZE_FORMAT "k, %s",
stack_size / K, guard_size / K,
(detachstate == PTHREAD_CREATE_DETACHED ? "detached" : "joinable"));
return buf;
}
char* os::Posix::realpath(const char* filename, char* outbuf, size_t outbuflen) {
if (filename == NULL || outbuf == NULL || outbuflen < 1) {
assert(false, "os::Posix::realpath: invalid arguments.");
errno = EINVAL;
return NULL;
}
char* result = NULL;
// This assumes platform realpath() is implemented according to POSIX.1-2008.
// POSIX.1-2008 allows to specify NULL for the output buffer, in which case
// output buffer is dynamically allocated and must be ::free()'d by the caller.
ALLOW_C_FUNCTION(::realpath, char* p = ::realpath(filename, NULL);)
if (p != NULL) {
if (strlen(p) < outbuflen) {
strcpy(outbuf, p);
result = outbuf;
} else {
errno = ENAMETOOLONG;
}
ALLOW_C_FUNCTION(::free, ::free(p);) // *not* os::free
} else {
// Fallback for platforms struggling with modern Posix standards (AIX 5.3, 6.1). If realpath
// returns EINVAL, this may indicate that realpath is not POSIX.1-2008 compatible and
// that it complains about the NULL we handed down as user buffer.
// In this case, use the user provided buffer but at least check whether realpath caused
// a memory overwrite.
if (errno == EINVAL) {
outbuf[outbuflen - 1] = '\0';
ALLOW_C_FUNCTION(::realpath, p = ::realpath(filename, outbuf);)
if (p != NULL) {
guarantee(outbuf[outbuflen - 1] == '\0', "realpath buffer overwrite detected.");
result = p;
}
}
}
return result;
}
int os::stat(const char *path, struct stat *sbuf) {
return ::stat(path, sbuf);
}
char * os::native_path(char *path) {
return path;
}
bool os::same_files(const char* file1, const char* file2) {
if (file1 == nullptr && file2 == nullptr) {
return true;
}
if (file1 == nullptr || file2 == nullptr) {
return false;
}
if (strcmp(file1, file2) == 0) {
return true;
}
bool is_same = false;
struct stat st1;
struct stat st2;
if (os::stat(file1, &st1) < 0) {
return false;
}
if (os::stat(file2, &st2) < 0) {
return false;
}
if (st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino) {
// same files
is_same = true;
}
return is_same;
}
// Called when creating the thread. The minimum stack sizes have already been calculated
size_t os::Posix::get_initial_stack_size(ThreadType thr_type, size_t req_stack_size) {
size_t stack_size;
if (req_stack_size == 0) {
stack_size = default_stack_size(thr_type);
} else {
stack_size = req_stack_size;
}
switch (thr_type) {
case os::java_thread:
// Java threads use ThreadStackSize which default value can be
// changed with the flag -Xss
if (req_stack_size == 0 && JavaThread::stack_size_at_create() > 0) {
// no requested size and we have a more specific default value
stack_size = JavaThread::stack_size_at_create();
}
stack_size = MAX2(stack_size,
_java_thread_min_stack_allowed);
break;
case os::compiler_thread:
if (req_stack_size == 0 && CompilerThreadStackSize > 0) {
// no requested size and we have a more specific default value
stack_size = (size_t)(CompilerThreadStackSize * K);
}
stack_size = MAX2(stack_size,
_compiler_thread_min_stack_allowed);
break;
case os::vm_thread:
case os::gc_thread:
case os::watcher_thread:
default: // presume the unknown thr_type is a VM internal
if (req_stack_size == 0 && VMThreadStackSize > 0) {
// no requested size and we have a more specific default value
stack_size = (size_t)(VMThreadStackSize * K);
}
stack_size = MAX2(stack_size,
_vm_internal_thread_min_stack_allowed);
break;
}
// pthread_attr_setstacksize() may require that the size be rounded up to the OS page size.
// Be careful not to round up to 0. Align down in that case.
if (stack_size <= SIZE_MAX - vm_page_size()) {
stack_size = align_up(stack_size, vm_page_size());
} else {
stack_size = align_down(stack_size, vm_page_size());
}
return stack_size;
}
#ifndef ZERO
#ifndef ARM
static bool get_frame_at_stack_banging_point(JavaThread* thread, address pc, const void* ucVoid, frame* fr) {
if (Interpreter::contains(pc)) {
// interpreter performs stack banging after the fixed frame header has
// been generated while the compilers perform it before. To maintain
// semantic consistency between interpreted and compiled frames, the
// method returns the Java sender of the current frame.
*fr = os::fetch_frame_from_context(ucVoid);
if (!fr->is_first_java_frame()) {
// get_frame_at_stack_banging_point() is only called when we
// have well defined stacks so java_sender() calls do not need
// to assert safe_for_sender() first.
*fr = fr->java_sender();
}
} else {
// more complex code with compiled code
assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
CodeBlob* cb = CodeCache::find_blob(pc);
if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
// Not sure where the pc points to, fallback to default
// stack overflow handling
return false;
} else {
// in compiled code, the stack banging is performed just after the return pc
// has been pushed on the stack
*fr = os::fetch_compiled_frame_from_context(ucVoid);
if (!fr->is_java_frame()) {
assert(!fr->is_first_frame(), "Safety check");
// See java_sender() comment above.
*fr = fr->java_sender();
}
}
}
assert(fr->is_java_frame(), "Safety check");
return true;
}
#endif // ARM
// This return true if the signal handler should just continue, ie. return after calling this
bool os::Posix::handle_stack_overflow(JavaThread* thread, address addr, address pc,
const void* ucVoid, address* stub) {
// stack overflow
StackOverflow* overflow_state = thread->stack_overflow_state();
if (overflow_state->in_stack_yellow_reserved_zone(addr)) {
if (thread->thread_state() == _thread_in_Java) {
#ifndef ARM
// arm32 doesn't have this
// vthreads don't support this
if (!thread->is_vthread_mounted() && overflow_state->in_stack_reserved_zone(addr)) {
frame fr;
if (get_frame_at_stack_banging_point(thread, pc, ucVoid, &fr)) {
assert(fr.is_java_frame(), "Must be a Java frame");
frame activation =
SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
if (activation.sp() != NULL) {
overflow_state->disable_stack_reserved_zone();
if (activation.is_interpreted_frame()) {
overflow_state->set_reserved_stack_activation((address)(activation.fp()
// Some platforms use frame pointers for interpreter frames, others use initial sp.
#if !defined(PPC64) && !defined(S390)
+ frame::interpreter_frame_initial_sp_offset
#endif
));
} else {
overflow_state->set_reserved_stack_activation((address)activation.unextended_sp());
}
return true; // just continue
}
}
}
#endif // ARM
// Throw a stack overflow exception. Guard pages will be re-enabled
// while unwinding the stack.
overflow_state->disable_stack_yellow_reserved_zone();
*stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
} else {
// Thread was in the vm or native code. Return and try to finish.
overflow_state->disable_stack_yellow_reserved_zone();
return true; // just continue
}
} else if (overflow_state->in_stack_red_zone(addr)) {
// Fatal red zone violation. Disable the guard pages and keep
// on handling the signal.
overflow_state->disable_stack_red_zone();
tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
// This is a likely cause, but hard to verify. Let's just print
// it as a hint.
tty->print_raw_cr("Please check if any of your loaded .so files has "
"enabled executable stack (see man page execstack(8))");
} else {
#ifdef LINUX
// This only works with os::Linux::manually_expand_stack()
// Accessing stack address below sp may cause SEGV if current
// thread has MAP_GROWSDOWN stack. This should only happen when
// current thread was created by user code with MAP_GROWSDOWN flag
// and then attached to VM. See notes in os_linux.cpp.
if (thread->osthread()->expanding_stack() == 0) {
thread->osthread()->set_expanding_stack();
if (os::Linux::manually_expand_stack(thread, addr)) {
thread->osthread()->clear_expanding_stack();
return true; // just continue
}
thread->osthread()->clear_expanding_stack();
} else {
fatal("recursive segv. expanding stack.");
}
#else
tty->print_raw_cr("SIGSEGV happened inside stack but outside yellow and red zone.");
#endif // LINUX
}
return false;
}
#endif // ZERO
bool os::Posix::is_root(uid_t uid){
return ROOT_UID == uid;
}
bool os::Posix::matches_effective_uid_or_root(uid_t uid) {
return is_root(uid) || geteuid() == uid;
}
bool os::Posix::matches_effective_uid_and_gid_or_root(uid_t uid, gid_t gid) {
return is_root(uid) || (geteuid() == uid && getegid() == gid);
}
// Shared clock/time and other supporting routines for pthread_mutex/cond
// initialization. This is enabled on Solaris but only some of the clock/time
// functionality is actually used there.
// Shared condattr object for use with relative timed-waits. Will be associated
// with CLOCK_MONOTONIC if available to avoid issues with time-of-day changes,
// but otherwise whatever default is used by the platform - generally the
// time-of-day clock.
static pthread_condattr_t _condAttr[1];
// Shared mutexattr to explicitly set the type to PTHREAD_MUTEX_NORMAL as not
// all systems (e.g. FreeBSD) map the default to "normal".
static pthread_mutexattr_t _mutexAttr[1];
// common basic initialization that is always supported
static void pthread_init_common(void) {
int status;
if ((status = pthread_condattr_init(_condAttr)) != 0) {
fatal("pthread_condattr_init: %s", os::strerror(status));
}
if ((status = pthread_mutexattr_init(_mutexAttr)) != 0) {
fatal("pthread_mutexattr_init: %s", os::strerror(status));
}
if ((status = pthread_mutexattr_settype(_mutexAttr, PTHREAD_MUTEX_NORMAL)) != 0) {
fatal("pthread_mutexattr_settype: %s", os::strerror(status));
}
PlatformMutex::init();
}
static int (*_pthread_condattr_setclock)(pthread_condattr_t *, clockid_t) = NULL;
static bool _use_clock_monotonic_condattr = false;
// Determine what POSIX API's are present and do appropriate
// configuration.
void os::Posix::init(void) {
#if defined(_ALLBSD_SOURCE)
clock_tics_per_sec = CLK_TCK;
#else
clock_tics_per_sec = sysconf(_SC_CLK_TCK);
#endif
// NOTE: no logging available when this is called. Put logging
// statements in init_2().
// Check for pthread_condattr_setclock support.
// libpthread is already loaded.
int (*condattr_setclock_func)(pthread_condattr_t*, clockid_t) =
(int (*)(pthread_condattr_t*, clockid_t))dlsym(RTLD_DEFAULT,
"pthread_condattr_setclock");
if (condattr_setclock_func != NULL) {
_pthread_condattr_setclock = condattr_setclock_func;
}
// Now do general initialization.
pthread_init_common();
int status;
if (_pthread_condattr_setclock != NULL) {
if ((status = _pthread_condattr_setclock(_condAttr, CLOCK_MONOTONIC)) != 0) {
if (status == EINVAL) {
_use_clock_monotonic_condattr = false;
warning("Unable to use monotonic clock with relative timed-waits" \
" - changes to the time-of-day clock may have adverse affects");
} else {
fatal("pthread_condattr_setclock: %s", os::strerror(status));
}
} else {
_use_clock_monotonic_condattr = true;
}
}
initial_time_count = javaTimeNanos();
}
void os::Posix::init_2(void) {
log_info(os)("Use of CLOCK_MONOTONIC is supported");
log_info(os)("Use of pthread_condattr_setclock is%s supported",
(_pthread_condattr_setclock != NULL ? "" : " not"));
log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with %s",
_use_clock_monotonic_condattr ? "CLOCK_MONOTONIC" : "the default clock");
}
// Utility to convert the given timeout to an absolute timespec
// (based on the appropriate clock) to use with pthread_cond_timewait,
// and sem_timedwait().
// The clock queried here must be the clock used to manage the
// timeout of the condition variable or semaphore.
//
// The passed in timeout value is either a relative time in nanoseconds
// or an absolute time in milliseconds. A relative timeout will be
// associated with CLOCK_MONOTONIC if available, unless the real-time clock
// is explicitly requested; otherwise, or if absolute,
// the default time-of-day clock will be used.
// Given time is a 64-bit value and the time_t used in the timespec is
// sometimes a signed-32-bit value we have to watch for overflow if times
// way in the future are given. Further on Solaris versions
// prior to 10 there is a restriction (see cond_timedwait) that the specified
// number of seconds, in abstime, is less than current_time + 100000000.
// As it will be over 20 years before "now + 100000000" will overflow we can
// ignore overflow and just impose a hard-limit on seconds using the value
// of "now + 100000000". This places a limit on the timeout of about 3.17
// years from "now".
//
#define MAX_SECS 100000000
// Calculate a new absolute time that is "timeout" nanoseconds from "now".
// "unit" indicates the unit of "now_part_sec" (may be nanos or micros depending
// on which clock API is being used).
static void calc_rel_time(timespec* abstime, jlong timeout, jlong now_sec,
jlong now_part_sec, jlong unit) {
time_t max_secs = now_sec + MAX_SECS;
jlong seconds = timeout / NANOUNITS;
timeout %= NANOUNITS; // remaining nanos
if (seconds >= MAX_SECS) {
// More seconds than we can add, so pin to max_secs.
abstime->tv_sec = max_secs;
abstime->tv_nsec = 0;
} else {
abstime->tv_sec = now_sec + seconds;
long nanos = (now_part_sec * (NANOUNITS / unit)) + timeout;
if (nanos >= NANOUNITS) { // overflow
abstime->tv_sec += 1;
nanos -= NANOUNITS;
}
abstime->tv_nsec = nanos;
}
}
// Unpack the given deadline in milliseconds since the epoch, into the given timespec.
// The current time in seconds is also passed in to enforce an upper bound as discussed above.
static void unpack_abs_time(timespec* abstime, jlong deadline, jlong now_sec) {
time_t max_secs = now_sec + MAX_SECS;
jlong seconds = deadline / MILLIUNITS;
jlong millis = deadline % MILLIUNITS;
if (seconds >= max_secs) {
// Absolute seconds exceeds allowed max, so pin to max_secs.
abstime->tv_sec = max_secs;
abstime->tv_nsec = 0;
} else {
abstime->tv_sec = seconds;
abstime->tv_nsec = millis_to_nanos(millis);
}
}
static jlong millis_to_nanos_bounded(jlong millis) {
// We have to watch for overflow when converting millis to nanos,
// but if millis is that large then we will end up limiting to
// MAX_SECS anyway, so just do that here.
if (millis / MILLIUNITS > MAX_SECS) {
millis = jlong(MAX_SECS) * MILLIUNITS;
}
return millis_to_nanos(millis);
}
static void to_abstime(timespec* abstime, jlong timeout,
bool isAbsolute, bool isRealtime) {
DEBUG_ONLY(int max_secs = MAX_SECS;)
if (timeout < 0) {
timeout = 0;
}
clockid_t clock = CLOCK_MONOTONIC;
if (isAbsolute || (!_use_clock_monotonic_condattr || isRealtime)) {
clock = CLOCK_REALTIME;
}
struct timespec now;
int status = clock_gettime(clock, &now);
assert(status == 0, "clock_gettime error: %s", os::strerror(errno));
if (!isAbsolute) {
calc_rel_time(abstime, timeout, now.tv_sec, now.tv_nsec, NANOUNITS);
} else {
unpack_abs_time(abstime, timeout, now.tv_sec);
}
DEBUG_ONLY(max_secs += now.tv_sec;)
assert(abstime->tv_sec >= 0, "tv_sec < 0");
assert(abstime->tv_sec <= max_secs, "tv_sec > max_secs");
assert(abstime->tv_nsec >= 0, "tv_nsec < 0");
assert(abstime->tv_nsec < NANOUNITS, "tv_nsec >= NANOUNITS");
}
// Create an absolute time 'millis' milliseconds in the future, using the
// real-time (time-of-day) clock. Used by PosixSemaphore.
void os::Posix::to_RTC_abstime(timespec* abstime, int64_t millis) {
to_abstime(abstime, millis_to_nanos_bounded(millis),
false /* not absolute */,
true /* use real-time clock */);
}
// Common (partly) shared time functions
jlong os::javaTimeMillis() {
struct timespec ts;
int status = clock_gettime(CLOCK_REALTIME, &ts);
assert(status == 0, "clock_gettime error: %s", os::strerror(errno));
return jlong(ts.tv_sec) * MILLIUNITS +
jlong(ts.tv_nsec) / NANOUNITS_PER_MILLIUNIT;
}
void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
struct timespec ts;
int status = clock_gettime(CLOCK_REALTIME, &ts);
assert(status == 0, "clock_gettime error: %s", os::strerror(errno));
seconds = jlong(ts.tv_sec);
nanos = jlong(ts.tv_nsec);
}
// macOS and AIX have platform specific implementations for javaTimeNanos()
// using native clock/timer access APIs. These have historically worked well
// for those platforms, but it may be possible for them to switch to the
// generic clock_gettime mechanism in the future.
#if !defined(__APPLE__) && !defined(AIX)
jlong os::javaTimeNanos() {
struct timespec tp;
int status = clock_gettime(CLOCK_MONOTONIC, &tp);
assert(status == 0, "clock_gettime error: %s", os::strerror(errno));
jlong result = jlong(tp.tv_sec) * NANOSECS_PER_SEC + jlong(tp.tv_nsec);
return result;
}
// for timer info max values which include all bits
#define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
// CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
info_ptr->max_value = ALL_64_BITS;
info_ptr->may_skip_backward = false; // not subject to resetting or drifting
info_ptr->may_skip_forward = false; // not subject to resetting or drifting
info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
}
#endif // ! APPLE && !AIX
// Time since start-up in seconds to a fine granularity.
double os::elapsedTime() {
return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
}
jlong os::elapsed_counter() {
return os::javaTimeNanos() - initial_time_count;
}
jlong os::elapsed_frequency() {
return NANOSECS_PER_SEC; // nanosecond resolution
}
bool os::supports_vtime() { return true; }
// Return the real, user, and system times in seconds from an
// arbitrary fixed point in the past.
bool os::getTimesSecs(double* process_real_time,
double* process_user_time,
double* process_system_time) {
struct tms ticks;
clock_t real_ticks = times(&ticks);
if (real_ticks == (clock_t) (-1)) {
return false;
} else {
double ticks_per_second = (double) clock_tics_per_sec;
*process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
*process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
*process_real_time = ((double) real_ticks) / ticks_per_second;
return true;
}
}
char * os::local_time_string(char *buf, size_t buflen) {
struct tm t;
time_t long_time;
time(&long_time);
localtime_r(&long_time, &t);
jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
t.tm_hour, t.tm_min, t.tm_sec);
return buf;
}
struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
return localtime_r(clock, res);
}
// PlatformEvent
//
// Assumption:
// Only one parker can exist on an event, which is why we allocate
// them per-thread. Multiple unparkers can coexist.
//
// _event serves as a restricted-range semaphore.
// -1 : thread is blocked, i.e. there is a waiter
// 0 : neutral: thread is running or ready,
// could have been signaled after a wait started
// 1 : signaled - thread is running or ready
//
// Having three states allows for some detection of bad usage - see
// comments on unpark().
PlatformEvent::PlatformEvent() {
int status = pthread_cond_init(_cond, _condAttr);
assert_status(status == 0, status, "cond_init");
status = pthread_mutex_init(_mutex, _mutexAttr);
assert_status(status == 0, status, "mutex_init");
_event = 0;
_nParked = 0;
}
void PlatformEvent::park() { // AKA "down()"
// Transitions for _event:
// -1 => -1 : illegal
// 1 => 0 : pass - return immediately
// 0 => -1 : block; then set _event to 0 before returning
// Invariant: Only the thread associated with the PlatformEvent
// may call park().
assert(_nParked == 0, "invariant");
int v;
// atomically decrement _event
for (;;) {
v = _event;
if (Atomic::cmpxchg(&_event, v, v - 1) == v) break;
}
guarantee(v >= 0, "invariant");
if (v == 0) { // Do this the hard way by blocking ...
int status = pthread_mutex_lock(_mutex);
assert_status(status == 0, status, "mutex_lock");
guarantee(_nParked == 0, "invariant");
++_nParked;
while (_event < 0) {
// OS-level "spurious wakeups" are ignored
status = pthread_cond_wait(_cond, _mutex);
assert_status(status == 0 MACOS_ONLY(|| status == ETIMEDOUT),
status, "cond_wait");
}
--_nParked;
_event = 0;
status = pthread_mutex_unlock(_mutex);
assert_status(status == 0, status, "mutex_unlock");
// Paranoia to ensure our locked and lock-free paths interact
// correctly with each other.
OrderAccess::fence();
}
guarantee(_event >= 0, "invariant");
}
int PlatformEvent::park(jlong millis) {
// Transitions for _event:
// -1 => -1 : illegal
// 1 => 0 : pass - return immediately
// 0 => -1 : block; then set _event to 0 before returning
// Invariant: Only the thread associated with the Event/PlatformEvent
// may call park().
assert(_nParked == 0, "invariant");
int v;
// atomically decrement _event
for (;;) {
v = _event;
if (Atomic::cmpxchg(&_event, v, v - 1) == v) break;
}
guarantee(v >= 0, "invariant");
if (v == 0) { // Do this the hard way by blocking ...
struct timespec abst;
to_abstime(&abst, millis_to_nanos_bounded(millis), false, false);
int ret = OS_TIMEOUT;
int status = pthread_mutex_lock(_mutex);
assert_status(status == 0, status, "mutex_lock");
guarantee(_nParked == 0, "invariant");
++_nParked;
while (_event < 0) {
status = pthread_cond_timedwait(_cond, _mutex, &abst);
assert_status(status == 0 || status == ETIMEDOUT,
status, "cond_timedwait");
// OS-level "spurious wakeups" are ignored
if (status == ETIMEDOUT) break;
}
--_nParked;
if (_event >= 0) {
ret = OS_OK;
}
_event = 0;
status = pthread_mutex_unlock(_mutex);
assert_status(status == 0, status, "mutex_unlock");
// Paranoia to ensure our locked and lock-free paths interact
// correctly with each other.
OrderAccess::fence();
return ret;
}
return OS_OK;
}
void PlatformEvent::unpark() {
// Transitions for _event:
// 0 => 1 : just return
// 1 => 1 : just return
// -1 => either 0 or 1; must signal target thread
// That is, we can safely transition _event from -1 to either
// 0 or 1.
// See also: "Semaphores in Plan 9" by Mullender & Cox
//
// Note: Forcing a transition from "-1" to "1" on an unpark() means
// that it will take two back-to-back park() calls for the owning
// thread to block. This has the benefit of forcing a spurious return
// from the first park() call after an unpark() call which will help
// shake out uses of park() and unpark() without checking state conditions
// properly. This spurious return doesn't manifest itself in any user code
// but only in the correctly written condition checking loops of ObjectMonitor,
// Mutex/Monitor, and JavaThread::sleep
if (Atomic::xchg(&_event, 1) >= 0) return;
int status = pthread_mutex_lock(_mutex);
assert_status(status == 0, status, "mutex_lock");
int anyWaiters = _nParked;
assert(anyWaiters == 0 || anyWaiters == 1, "invariant");
status = pthread_mutex_unlock(_mutex);
assert_status(status == 0, status, "mutex_unlock");
// Note that we signal() *after* dropping the lock for "immortal" Events.
// This is safe and avoids a common class of futile wakeups. In rare
// circumstances this can cause a thread to return prematurely from
// cond_{timed}wait() but the spurious wakeup is benign and the victim
// will simply re-test the condition and re-park itself.
// This provides particular benefit if the underlying platform does not
// provide wait morphing.
if (anyWaiters != 0) {
status = pthread_cond_signal(_cond);
assert_status(status == 0, status, "cond_signal");
}
}
// JSR166 support
PlatformParker::PlatformParker() : _counter(0), _cur_index(-1) {
int status = pthread_cond_init(&_cond[REL_INDEX], _condAttr);
assert_status(status == 0, status, "cond_init rel");
status = pthread_cond_init(&_cond[ABS_INDEX], NULL);
assert_status(status == 0, status, "cond_init abs");
status = pthread_mutex_init(_mutex, _mutexAttr);
assert_status(status == 0, status, "mutex_init");
}
PlatformParker::~PlatformParker() {
int status = pthread_cond_destroy(&_cond[REL_INDEX]);
assert_status(status == 0, status, "cond_destroy rel");
status = pthread_cond_destroy(&_cond[ABS_INDEX]);
assert_status(status == 0, status, "cond_destroy abs");
status = pthread_mutex_destroy(_mutex);
assert_status(status == 0, status, "mutex_destroy");
}
// Parker::park decrements count if > 0, else does a condvar wait. Unpark
// sets count to 1 and signals condvar. Only one thread ever waits
// on the condvar. Contention seen when trying to park implies that someone
// is unparking you, so don't wait. And spurious returns are fine, so there
// is no need to track notifications.
void Parker::park(bool isAbsolute, jlong time) {
// Optional fast-path check:
// Return immediately if a permit is available.
// We depend on Atomic::xchg() having full barrier semantics
// since we are doing a lock-free update to _counter.
if (Atomic::xchg(&_counter, 0) > 0) return;
JavaThread *jt = JavaThread::current();
// Optional optimization -- avoid state transitions if there's
// an interrupt pending.
if (jt->is_interrupted(false)) {
return;
}
// Next, demultiplex/decode time arguments
struct timespec absTime;
if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
return;
}
if (time > 0) {
to_abstime(&absTime, time, isAbsolute, false);
}
// Enter safepoint region
// Beware of deadlocks such as 6317397.
// The per-thread Parker:: mutex is a classic leaf-lock.
// In particular a thread must never block on the Threads_lock while
// holding the Parker:: mutex. If safepoints are pending both the
// the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
ThreadBlockInVM tbivm(jt);
// Can't access interrupt state now that we are _thread_blocked. If we've
// been interrupted since we checked above then _counter will be > 0.
// Don't wait if cannot get lock since interference arises from
// unparking.
if (pthread_mutex_trylock(_mutex) != 0) {
return;
}
int status;
if (_counter > 0) { // no wait needed
_counter = 0;
status = pthread_mutex_unlock(_mutex);
assert_status(status == 0, status, "invariant");
// Paranoia to ensure our locked and lock-free paths interact
// correctly with each other and Java-level accesses.
OrderAccess::fence();
return;
}
OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
assert(_cur_index == -1, "invariant");
if (time == 0) {
_cur_index = REL_INDEX; // arbitrary choice when not timed
status = pthread_cond_wait(&_cond[_cur_index], _mutex);
assert_status(status == 0 MACOS_ONLY(|| status == ETIMEDOUT),
status, "cond_wait");
}
else {
_cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime);
assert_status(status == 0 || status == ETIMEDOUT,
status, "cond_timedwait");
}
_cur_index = -1;
_counter = 0;
status = pthread_mutex_unlock(_mutex);
assert_status(status == 0, status, "invariant");
// Paranoia to ensure our locked and lock-free paths interact
// correctly with each other and Java-level accesses.
OrderAccess::fence();
}
void Parker::unpark() {
int status = pthread_mutex_lock(_mutex);
assert_status(status == 0, status, "invariant");
const int s = _counter;
_counter = 1;
// must capture correct index before unlocking
int index = _cur_index;
status = pthread_mutex_unlock(_mutex);
assert_status(status == 0, status, "invariant");
// Note that we signal() *after* dropping the lock for "immortal" Events.
// This is safe and avoids a common class of futile wakeups. In rare
// circumstances this can cause a thread to return prematurely from
// cond_{timed}wait() but the spurious wakeup is benign and the victim
// will simply re-test the condition and re-park itself.
// This provides particular benefit if the underlying platform does not
// provide wait morphing.
if (s < 1 && index != -1) {
// thread is definitely parked
status = pthread_cond_signal(&_cond[index]);
assert_status(status == 0, status, "invariant");
}
}
// Platform Mutex/Monitor implementation
#if PLATFORM_MONITOR_IMPL_INDIRECT
PlatformMutex::Mutex::Mutex() : _next(NULL) {
int status = pthread_mutex_init(&_mutex, _mutexAttr);
assert_status(status == 0, status, "mutex_init");
}
PlatformMutex::Mutex::~Mutex() {
int status = pthread_mutex_destroy(&_mutex);
assert_status(status == 0, status, "mutex_destroy");
}
pthread_mutex_t PlatformMutex::_freelist_lock;
PlatformMutex::Mutex* PlatformMutex::_mutex_freelist = NULL;
void PlatformMutex::init() {
int status = pthread_mutex_init(&_freelist_lock, _mutexAttr);
assert_status(status == 0, status, "freelist lock init");
}
struct PlatformMutex::WithFreeListLocked : public StackObj {
WithFreeListLocked() {
int status = pthread_mutex_lock(&_freelist_lock);
assert_status(status == 0, status, "freelist lock");
}
~WithFreeListLocked() {
int status = pthread_mutex_unlock(&_freelist_lock);
assert_status(status == 0, status, "freelist unlock");
}
};
PlatformMutex::PlatformMutex() {
{
WithFreeListLocked wfl;
_impl = _mutex_freelist;
if (_impl != NULL) {
_mutex_freelist = _impl->_next;
_impl->_next = NULL;
return;
}
}
_impl = new Mutex();
}
PlatformMutex::~PlatformMutex() {
WithFreeListLocked wfl;
assert(_impl->_next == NULL, "invariant");
_impl->_next = _mutex_freelist;
_mutex_freelist = _impl;
}
PlatformMonitor::Cond::Cond() : _next(NULL) {
int status = pthread_cond_init(&_cond, _condAttr);
assert_status(status == 0, status, "cond_init");
}
PlatformMonitor::Cond::~Cond() {
int status = pthread_cond_destroy(&_cond);
assert_status(status == 0, status, "cond_destroy");
}
PlatformMonitor::Cond* PlatformMonitor::_cond_freelist = NULL;
PlatformMonitor::PlatformMonitor() {
{
WithFreeListLocked wfl;
_impl = _cond_freelist;
if (_impl != NULL) {
_cond_freelist = _impl->_next;
_impl->_next = NULL;
return;
}
}
_impl = new Cond();
}
PlatformMonitor::~PlatformMonitor() {
WithFreeListLocked wfl;
assert(_impl->_next == NULL, "invariant");
_impl->_next = _cond_freelist;
_cond_freelist = _impl;
}
#else
PlatformMutex::PlatformMutex() {
int status = pthread_mutex_init(&_mutex, _mutexAttr);
assert_status(status == 0, status, "mutex_init");
}
PlatformMutex::~PlatformMutex() {
int status = pthread_mutex_destroy(&_mutex);
assert_status(status == 0, status, "mutex_destroy");
}
PlatformMonitor::PlatformMonitor() {
int status = pthread_cond_init(&_cond, _condAttr);
assert_status(status == 0, status, "cond_init");
}
PlatformMonitor::~PlatformMonitor() {
int status = pthread_cond_destroy(&_cond);
assert_status(status == 0, status, "cond_destroy");
}
#endif // PLATFORM_MONITOR_IMPL_INDIRECT
// Must already be locked
int PlatformMonitor::wait(jlong millis) {
assert(millis >= 0, "negative timeout");
if (millis > 0) {
struct timespec abst;
// We have to watch for overflow when converting millis to nanos,
// but if millis is that large then we will end up limiting to
// MAX_SECS anyway, so just do that here.
if (millis / MILLIUNITS > MAX_SECS) {
millis = jlong(MAX_SECS) * MILLIUNITS;
}
to_abstime(&abst, millis_to_nanos(millis), false, false);
int ret = OS_TIMEOUT;
int status = pthread_cond_timedwait(cond(), mutex(), &abst);
assert_status(status == 0 || status == ETIMEDOUT,
status, "cond_timedwait");
if (status == 0) {
ret = OS_OK;
}
return ret;
} else {
int status = pthread_cond_wait(cond(), mutex());
assert_status(status == 0 MACOS_ONLY(|| status == ETIMEDOUT),
status, "cond_wait");
return OS_OK;
}
}
// Darwin has no "environ" in a dynamic library.
#ifdef __APPLE__
#define environ (*_NSGetEnviron())
#else
extern char** environ;
#endif
char** os::get_environ() { return environ; }
// Run the specified command in a separate process. Return its exit value,
// or -1 on failure (e.g. can't fork a new process).
// Notes: -Unlike system(), this function can be called from signal handler. It
// doesn't block SIGINT et al.
// -this function is unsafe to use in non-error situations, mainly
// because the child process will inherit all parent descriptors.
int os::fork_and_exec(const char* cmd) {
const char* argv[4] = {"sh", "-c", cmd, NULL};
pid_t pid = -1;
char** env = os::get_environ();
// Note: cast is needed because posix_spawn() requires - for compatibility with ancient
// C-code - a non-const argv/envp pointer array. But it is fine to hand in literal
// strings and just cast the constness away. See also ProcessImpl_md.c.
int rc = ::posix_spawn(&pid, "/bin/sh", NULL, NULL, (char**) argv, env);
if (rc == 0) {
int status;
// Wait for the child process to exit. This returns immediately if
// the child has already exited. */
while (::waitpid(pid, &status, 0) < 0) {
switch (errno) {
case ECHILD: return 0;
case EINTR: break;
default: return -1;
}
}
if (WIFEXITED(status)) {
// The child exited normally; get its exit code.
return WEXITSTATUS(status);
} else if (WIFSIGNALED(status)) {
// The child exited because of a signal
// The best value to return is 0x80 + signal number,
// because that is what all Unix shells do, and because
// it allows callers to distinguish between process exit and
// process death by signal.
return 0x80 + WTERMSIG(status);
} else {
// Unknown exit code; pass it through
return status;
}
} else {
// Don't log, we are inside error handling
return -1;
}
}
bool os::message_box(const char* title, const char* message) {
int i;
fdStream err(defaultStream::error_fd());
for (i = 0; i < 78; i++) err.print_raw("=");
err.cr();
err.print_raw_cr(title);
for (i = 0; i < 78; i++) err.print_raw("-");
err.cr();
err.print_raw_cr(message);
for (i = 0; i < 78; i++) err.print_raw("=");
err.cr();
char buf[16];
// Prevent process from exiting upon "read error" without consuming all CPU
while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
return buf[0] == 'y' || buf[0] == 'Y';
}
////////////////////////////////////////////////////////////////////////////////
// runtime exit support
// Note: os::shutdown() might be called very early during initialization, or
// called from signal handler. Before adding something to os::shutdown(), make
// sure it is async-safe and can handle partially initialized VM.
void os::shutdown() {
--> --------------------
--> maximum size reached
--> --------------------
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