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1de408bb4dfc0c5daf1edb04b0f15bb4397dccf5
ruby/thread_pthread.c
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Nobuyoshi Nakada 3e4497dab1 [Bug #20452] Take main thread address/size with rlimit if musl libc 
Musl libc defines `pthread_getattr_np` but it can not get the correct
value of the main thread.
2026-10-26 12:42:46 +09:00

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/* -*-c-*- */
/**********************************************************************
thread_pthread.c -
$Author$
Copyright (C) 2004-2007 Koichi Sasada
**********************************************************************/
#ifdef THREAD_SYSTEM_DEPENDENT_IMPLEMENTATION
#include "internal/gc.h"
#include "internal/sanitizers.h"
#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#endif
#ifdef HAVE_THR_STKSEGMENT
#include <thread.h>
#endif
#if defined(HAVE_FCNTL_H)
#include <fcntl.h>
#elif defined(HAVE_SYS_FCNTL_H)
#include <sys/fcntl.h>
#endif
#ifdef HAVE_SYS_PRCTL_H
#include <sys/prctl.h>
#endif
#if defined(HAVE_SYS_TIME_H)
#include <sys/time.h>
#endif
#if defined(__HAIKU__)
#include <kernel/OS.h>
#endif
#ifdef __linux__
#include <sys/syscall.h> /* for SYS_gettid */
#endif
#include <time.h>
#include <signal.h>
#include "probes.h"
#if defined(HAVE_SYS_EVENTFD_H) && defined(HAVE_EVENTFD)
# define USE_EVENTFD (1)
# include <sys/eventfd.h>
#else
# define USE_EVENTFD (0)
#endif
#if defined(HAVE_PTHREAD_CONDATTR_SETCLOCK) && \
defined(CLOCK_REALTIME) && defined(CLOCK_MONOTONIC) && \
defined(HAVE_CLOCK_GETTIME)
static pthread_condattr_t condattr_mono;
static pthread_condattr_t *condattr_monotonic = &condattr_mono;
#else
static const void *const condattr_monotonic = NULL;
#endif
// Whether native_cond_timedwait() takes an rb_hrtime_t deadline as is. It
// does when the condvar counts in the same clock rb_hrtime_now() reads;
// otherwise the caller has to restate the deadline in the condvar's clock.
#define RB_NATIVE_COND_HRTIME_DEADLINE_P() (condattr_monotonic != NULL)
#include COROUTINE_H
#ifndef HAVE_SYS_EVENT_H
#define HAVE_SYS_EVENT_H 0
#endif
#ifndef HAVE_SYS_EPOLL_H
#define HAVE_SYS_EPOLL_H 0
#else
// force setting for debug
// #undef HAVE_SYS_EPOLL_H
// #define HAVE_SYS_EPOLL_H 0
#endif
#ifndef USE_MN_THREADS
#if defined(__EMSCRIPTEN__) || defined(COROUTINE_PTHREAD_CONTEXT)
// on __EMSCRIPTEN__ provides epoll* declarations, but no implementations.
// on COROUTINE_PTHREAD_CONTEXT, it doesn't worth to use it.
#define USE_MN_THREADS 0
#elif HAVE_SYS_EPOLL_H
#include <sys/epoll.h>
#ifdef EPOLLONESHOT
#define USE_MN_THREADS 1
#else
// the scheduler arms io fds with EPOLLONESHOT (Linux 2.6.2)
#define USE_MN_THREADS 0
#endif
#elif HAVE_SYS_EVENT_H
#include <sys/event.h>
#define USE_MN_THREADS 1
#else
#define USE_MN_THREADS 0
#endif
#endif
#ifdef HAVE_SCHED_YIELD
#define native_thread_yield() (void)sched_yield()
#else
#define native_thread_yield() ((void)0)
#endif
// native thread wrappers
#define NATIVE_MUTEX_LOCK_DEBUG 0
#define NATIVE_MUTEX_LOCK_DEBUG_YIELD 0
static void
mutex_debug(const char *msg, void *lock)
{
if (NATIVE_MUTEX_LOCK_DEBUG) {
int r;
static pthread_mutex_t dbglock = PTHREAD_MUTEX_INITIALIZER;
if ((r = pthread_mutex_lock(&dbglock)) != 0) {exit(EXIT_FAILURE);}
fprintf(stdout, "%s: %p\n", msg, lock);
if ((r = pthread_mutex_unlock(&dbglock)) != 0) {exit(EXIT_FAILURE);}
}
}
void
rb_native_mutex_lock(pthread_mutex_t *lock)
{
int r;
#if NATIVE_MUTEX_LOCK_DEBUG_YIELD
native_thread_yield();
#endif
mutex_debug("lock", lock);
if ((r = pthread_mutex_lock(lock)) != 0) {
rb_bug_errno("pthread_mutex_lock", r);
}
}
void
rb_native_mutex_unlock(pthread_mutex_t *lock)
{
int r;
mutex_debug("unlock", lock);
if ((r = pthread_mutex_unlock(lock)) != 0) {
rb_bug_errno("pthread_mutex_unlock", r);
}
}
int
rb_native_mutex_trylock(pthread_mutex_t *lock)
{
int r;
mutex_debug("trylock", lock);
if ((r = pthread_mutex_trylock(lock)) != 0) {
if (r == EBUSY) {
return EBUSY;
}
else {
rb_bug_errno("pthread_mutex_trylock", r);
}
}
return 0;
}
void
rb_native_mutex_initialize(pthread_mutex_t *lock)
{
int r = pthread_mutex_init(lock, 0);
mutex_debug("init", lock);
if (r != 0) {
rb_bug_errno("pthread_mutex_init", r);
}
}
void
rb_native_mutex_destroy(pthread_mutex_t *lock)
{
int r = pthread_mutex_destroy(lock);
mutex_debug("destroy", lock);
if (r != 0) {
rb_bug_errno("pthread_mutex_destroy", r);
}
}
void
rb_native_cond_initialize(rb_nativethread_cond_t *cond)
{
int r = pthread_cond_init(cond, condattr_monotonic);
if (r != 0) {
rb_bug_errno("pthread_cond_init", r);
}
}
void
rb_native_cond_destroy(rb_nativethread_cond_t *cond)
{
int r = pthread_cond_destroy(cond);
if (r != 0) {
rb_bug_errno("pthread_cond_destroy", r);
}
}
/*
* In OS X 10.7 (Lion), pthread_cond_signal and pthread_cond_broadcast return
* EAGAIN after retrying 8192 times. You can see them in the following page:
*
* http://www.opensource.apple.com/source/Libc/Libc-763.11/pthreads/pthread_cond.c
*
* The following rb_native_cond_signal and rb_native_cond_broadcast functions
* need to retrying until pthread functions don't return EAGAIN.
*/
void
rb_native_cond_signal(rb_nativethread_cond_t *cond)
{
int r;
do {
r = pthread_cond_signal(cond);
} while (r == EAGAIN);
if (r != 0) {
rb_bug_errno("pthread_cond_signal", r);
}
}
void
rb_native_cond_broadcast(rb_nativethread_cond_t *cond)
{
int r;
do {
r = pthread_cond_broadcast(cond);
} while (r == EAGAIN);
if (r != 0) {
rb_bug_errno("rb_native_cond_broadcast", r);
}
}
void
rb_native_cond_wait(rb_nativethread_cond_t *cond, pthread_mutex_t *mutex)
{
int r = pthread_cond_wait(cond, mutex);
if (r != 0) {
rb_bug_errno("pthread_cond_wait", r);
}
}
static int
native_cond_timedwait(rb_nativethread_cond_t *cond, pthread_mutex_t *mutex, const rb_hrtime_t *abs)
{
int r;
struct timespec ts;
/*
* An old Linux may return EINTR. Even though POSIX says
* "These functions shall not return an error code of [EINTR]".
* http://pubs.opengroup.org/onlinepubs/009695399/functions/pthread_cond_timedwait.html
* Let's hide it from arch generic code.
*/
do {
rb_hrtime2timespec(&ts, abs);
r = pthread_cond_timedwait(cond, mutex, &ts);
} while (r == EINTR);
if (r != 0 && r != ETIMEDOUT) {
rb_bug_errno("pthread_cond_timedwait", r);
}
return r;
}
static rb_hrtime_t
native_cond_timeout(rb_nativethread_cond_t *cond, const rb_hrtime_t rel)
{
if (condattr_monotonic) {
return rb_hrtime_add(rb_hrtime_now(), rel);
}
else {
struct timespec ts;
rb_timespec_now(&ts);
return rb_hrtime_add(rb_timespec2hrtime(&ts), rel);
}
}
void
rb_native_cond_timedwait(rb_nativethread_cond_t *cond, pthread_mutex_t *mutex, unsigned long msec)
{
rb_hrtime_t hrmsec = native_cond_timeout(cond, RB_HRTIME_PER_MSEC * msec);
native_cond_timedwait(cond, mutex, &hrmsec);
}
// thread scheduling
static rb_internal_thread_event_hook_t *rb_internal_thread_event_hooks = NULL;
static void rb_thread_execute_hooks(rb_event_flag_t event, rb_thread_t *th);
#if 0
static const char *
event_name(rb_event_flag_t event)
{
switch (event) {
case RUBY_INTERNAL_THREAD_EVENT_STARTED:
return "STARTED";
case RUBY_INTERNAL_THREAD_EVENT_READY:
return "READY";
case RUBY_INTERNAL_THREAD_EVENT_RESUMED:
return "RESUMED";
case RUBY_INTERNAL_THREAD_EVENT_SUSPENDED:
return "SUSPENDED";
case RUBY_INTERNAL_THREAD_EVENT_EXITED:
return "EXITED";
}
return "no-event";
}
#define RB_INTERNAL_THREAD_HOOK(event, th) \
if (UNLIKELY(rb_internal_thread_event_hooks)) { \
fprintf(stderr, "[thread=%"PRIxVALUE"] %s in %s (%s:%d)\n", th->self, event_name(event), __func__, __FILE__, __LINE__); \
rb_thread_execute_hooks(event, th); \
}
#else
#define RB_INTERNAL_THREAD_HOOK(event, th) if (UNLIKELY(rb_internal_thread_event_hooks)) { rb_thread_execute_hooks(event, th); }
#endif
static rb_serial_t current_fork_gen = 1; /* We can't use GET_VM()->fork_gen */
#if defined(SIGVTALRM) && !defined(__EMSCRIPTEN__)
# define USE_UBF_LIST 1
#endif
#if USE_MN_THREADS
static void nt_machine_stack_atfork(void);
// A coroutine thread's execution context: the coroutine_context (first, so
// th->sched.context points at the whole block) plus what is needed to free
// it without the rb_thread_t. Owned by the execution: the dying thread marks
// it dead before its final transfer, and whichever context RESUMES from that
// transfer frees it -- the resume itself proves the transfer's register save
// into this block has completed, so no further synchronization is needed.
struct rb_thread_context {
struct coroutine_context co; // must be first
void *stack; // the coroutine machine stack (pool stack)
struct rb_native_thread *nt; // final transfer target, stashed at termination
bool dead;
};
static bool thread_sched_reclaim(struct coroutine_context *dead_co);
#endif
#ifdef RB_THREAD_T_HAS_NATIVE_ID
static int
get_native_thread_id(void)
{
#ifdef __linux__
return (int)syscall(SYS_gettid);
#elif defined(__FreeBSD__)
return pthread_getthreadid_np();
#endif
}
#endif
#ifdef RB_THREAD_LOCAL_SPECIFIER
static RB_THREAD_LOCAL_SPECIFIER rb_thread_t *ruby_native_thread;
#else
static pthread_key_t ruby_native_thread_key;
#endif
static void
null_func(int i)
{
/* null */
// This function can be called from signal handler
// RUBY_DEBUG_LOG("i:%d", i);
}
rb_thread_t *
ruby_thread_from_native(void)
{
#ifdef RB_THREAD_LOCAL_SPECIFIER
return ruby_native_thread;
#else
return pthread_getspecific(ruby_native_thread_key);
#endif
}
int
ruby_thread_set_native(rb_thread_t *th)
{
if (th) {
#ifdef USE_UBF_LIST
ccan_list_node_init(&th->sched.node.ubf);
#endif
}
// setup TLS
if (th && th->ec) {
rb_ractor_set_current_ec(th->ractor, th->ec);
}
#ifdef RB_THREAD_LOCAL_SPECIFIER
ruby_native_thread = th;
return 1;
#else
return pthread_setspecific(ruby_native_thread_key, th) == 0;
#endif
}
static void native_thread_setup(struct rb_native_thread *nt);
static void native_thread_setup_on_thread(struct rb_native_thread *nt);
// Internal cache of page size:
static size_t RB_THREAD_PAGE_SIZE;
void
Init_native_thread(rb_thread_t *main_th)
{
// Get the system page size for later use in stack allocation and stack overflow checks:
RB_THREAD_PAGE_SIZE = sysconf(_SC_PAGESIZE);
#if defined(HAVE_PTHREAD_CONDATTR_SETCLOCK)
if (condattr_monotonic) {
int r = pthread_condattr_init(condattr_monotonic);
if (r == 0) {
r = pthread_condattr_setclock(condattr_monotonic, CLOCK_MONOTONIC);
}
if (r) condattr_monotonic = NULL;
}
#endif
#ifndef RB_THREAD_LOCAL_SPECIFIER
if (pthread_key_create(&ruby_native_thread_key, 0) == EAGAIN) {
rb_bug("pthread_key_create failed (ruby_native_thread_key)");
}
if (pthread_key_create(&ruby_current_ec_key, 0) == EAGAIN) {
rb_bug("pthread_key_create failed (ruby_current_ec_key)");
}
#endif
ruby_posix_signal(SIGVTALRM, null_func);
// setup vm
rb_vm_t *vm = main_th->vm;
thread_sched_init_vm(vm);
// setup main thread
main_th->nt->thread_id = pthread_self();
main_th->nt->serial = 1;
#ifdef RUBY_NT_SERIAL
ruby_nt_serial = 1;
#endif
ruby_thread_set_native(main_th);
native_thread_setup(main_th->nt);
native_thread_setup_on_thread(main_th->nt);
TH_SCHED(main_th)->running = main_th;
main_th->has_dedicated_nt = 1;
// setup main NT (before the record below: its kind decides where it goes)
main_th->nt->dedicated = 1;
main_th->nt->running_thread = main_th;
main_th->nt->vm = vm;
thread_sched_setup_running_threads(TH_SCHED(main_th), main_th->ractor, vm, main_th, NULL);
// setup mn
#if USE_RUBY_DEBUG_LOG
vm->ractor.sched.dnt_cnt = 1;
#endif
}
static void
native_thread_destroy_atfork(struct rb_native_thread *nt)
{
if (nt) {
/* We can't call rb_native_cond_destroy here because according to the
* specs of pthread_cond_destroy:
*
* Attempting to destroy a condition variable upon which other threads
* are currently blocked results in undefined behavior.
*
* Specifically, glibc's pthread_cond_destroy waits on all the other
* listeners. Since after forking all the threads are dead, the condition
* variable's listeners will never wake up, so it will hang forever.
*/
RB_ALTSTACK_FREE(nt->altstack);
SIZED_FREE(nt->nt_context);
SIZED_FREE(nt);
}
}
static void
native_thread_destroy(struct rb_native_thread *nt)
{
if (nt) {
rb_native_cond_destroy(&nt->readyq);
rb_native_mutex_destroy(&nt->running_th_lock);
native_thread_destroy_atfork(nt);
}
}
// A retiring snt frees its own rb_native_thread as it exits. Disarm the
// altstack registration first: a signal between the free and the thread's
// end must not run on the freed block.
static void
native_thread_destroy_self(struct rb_native_thread *nt)
{
#ifdef USE_SIGALTSTACK
stack_t disable = {0};
disable.ss_flags = SS_DISABLE;
sigaltstack(&disable, NULL);
#endif
native_thread_destroy(nt);
}
#if defined HAVE_PTHREAD_GETATTR_NP || defined HAVE_PTHREAD_ATTR_GET_NP
#define STACKADDR_AVAILABLE 1
# if defined(__linux__) && !defined __GLIBC__
/* Musl libc defines `pthread_getattr_np` but it can not get the
* correct value of the main thread. */
# define MAINSTACKADDR_AVAILABLE 0
# endif
#elif defined HAVE_PTHREAD_GET_STACKADDR_NP && defined HAVE_PTHREAD_GET_STACKSIZE_NP
#define STACKADDR_AVAILABLE 1
#undef MAINSTACKADDR_AVAILABLE
#define MAINSTACKADDR_AVAILABLE 1
void *pthread_get_stackaddr_np(pthread_t);
size_t pthread_get_stacksize_np(pthread_t);
#elif defined HAVE_THR_STKSEGMENT || defined HAVE_PTHREAD_STACKSEG_NP
#define STACKADDR_AVAILABLE 1
#elif defined HAVE_PTHREAD_GETTHRDS_NP
#define STACKADDR_AVAILABLE 1
#elif defined __HAIKU__
#define STACKADDR_AVAILABLE 1
#endif
#ifndef MAINSTACKADDR_AVAILABLE
# ifdef STACKADDR_AVAILABLE
# define MAINSTACKADDR_AVAILABLE 1
# else
# define MAINSTACKADDR_AVAILABLE 0
# endif
#endif
#if MAINSTACKADDR_AVAILABLE && !defined(get_main_stack)
# define get_main_stack(addr, size) get_stack(addr, size)
#endif
#ifdef STACKADDR_AVAILABLE
/*
* Get the initial address and size of current thread's stack
*/
static int
get_stack(void **addr, size_t *size)
{
#define CHECK_ERR(expr) \
{int err = (expr); if (err) return err;}
#ifdef HAVE_PTHREAD_GETATTR_NP /* Linux */
pthread_attr_t attr;
size_t guard = 0;
STACK_GROW_DIR_DETECTION;
CHECK_ERR(pthread_getattr_np(pthread_self(), &attr));
# ifdef HAVE_PTHREAD_ATTR_GETSTACK
CHECK_ERR(pthread_attr_getstack(&attr, addr, size));
STACK_DIR_UPPER((void)0, (void)(*addr = (char *)*addr + *size));
# else
CHECK_ERR(pthread_attr_getstackaddr(&attr, addr));
CHECK_ERR(pthread_attr_getstacksize(&attr, size));
# endif
# ifdef HAVE_PTHREAD_ATTR_GETGUARDSIZE
CHECK_ERR(pthread_attr_getguardsize(&attr, &guard));
# else
guard = RB_THREAD_PAGE_SIZE;
# endif
*size -= guard;
pthread_attr_destroy(&attr);
#elif defined HAVE_PTHREAD_ATTR_GET_NP /* FreeBSD, DragonFly BSD, NetBSD */
pthread_attr_t attr;
CHECK_ERR(pthread_attr_init(&attr));
CHECK_ERR(pthread_attr_get_np(pthread_self(), &attr));
# ifdef HAVE_PTHREAD_ATTR_GETSTACK
CHECK_ERR(pthread_attr_getstack(&attr, addr, size));
# else
CHECK_ERR(pthread_attr_getstackaddr(&attr, addr));
CHECK_ERR(pthread_attr_getstacksize(&attr, size));
# endif
STACK_DIR_UPPER((void)0, (void)(*addr = (char *)*addr + *size));
pthread_attr_destroy(&attr);
#elif (defined HAVE_PTHREAD_GET_STACKADDR_NP && defined HAVE_PTHREAD_GET_STACKSIZE_NP) /* MacOS X */
pthread_t th = pthread_self();
*addr = pthread_get_stackaddr_np(th);
*size = pthread_get_stacksize_np(th);
#elif defined HAVE_THR_STKSEGMENT || defined HAVE_PTHREAD_STACKSEG_NP
stack_t stk;
# if defined HAVE_THR_STKSEGMENT /* Solaris */
CHECK_ERR(thr_stksegment(&stk));
# else /* OpenBSD */
CHECK_ERR(pthread_stackseg_np(pthread_self(), &stk));
# endif
*addr = stk.ss_sp;
*size = stk.ss_size;
#elif defined HAVE_PTHREAD_GETTHRDS_NP /* AIX */
pthread_t th = pthread_self();
struct __pthrdsinfo thinfo;
char reg[256];
int regsiz=sizeof(reg);
CHECK_ERR(pthread_getthrds_np(&th, PTHRDSINFO_QUERY_ALL,
&thinfo, sizeof(thinfo),
&reg, &regsiz));
*addr = thinfo.__pi_stackaddr;
/* Must not use thinfo.__pi_stacksize for size.
It is around 3KB smaller than the correct size
calculated by thinfo.__pi_stackend - thinfo.__pi_stackaddr. */
*size = thinfo.__pi_stackend - thinfo.__pi_stackaddr;
STACK_DIR_UPPER((void)0, (void)(*addr = (char *)*addr + *size));
#elif defined __HAIKU__
thread_info info;
STACK_GROW_DIR_DETECTION;
CHECK_ERR(get_thread_info(find_thread(NULL), &info));
*addr = info.stack_base;
*size = (uintptr_t)info.stack_end - (uintptr_t)info.stack_base;
STACK_DIR_UPPER((void)0, (void)(*addr = (char *)*addr + *size));
#else
#error STACKADDR_AVAILABLE is defined but not implemented.
#endif
return 0;
#undef CHECK_ERR
}
#endif
static struct {
rb_nativethread_id_t id;
size_t stack_maxsize;
VALUE *stack_start;
} native_main_thread;
// Whether the calling native thread may leave the shared pool. The process's
// main pthread cannot: under RUBY_MN_THREADS=2 its loop runs on a stack only
// it could free (thread_sched_main_to_shared). By pthread_self(), not
// nt->thread_id, which pthread_create may still be writing.
static bool
native_thread_self_can_retire_p(void)
{
return !pthread_equal(pthread_self(), native_main_thread.id);
}
#if defined(HAVE_WORKING_FORK)
// The forking thread's pthread is the child's only one, hence its main one
static void
native_main_thread_atfork(void)
{
native_main_thread.id = pthread_self();
// The stack recorded here is the parent's initial one; this thread's is
// another. Nothing reads it for a thread that is already running, and
// saying "unknown" beats saying the wrong bounds.
native_main_thread.stack_maxsize = 0;
}
#endif
#ifdef STACK_END_ADDRESS
extern void *STACK_END_ADDRESS;
#endif
static void
native_thread_init_main_thread_stack(void *addr)
{
native_main_thread.id = pthread_self();
#ifdef RUBY_ASAN_ENABLED
addr = asan_get_real_stack_addr((void *)addr);
#endif
#if MAINSTACKADDR_AVAILABLE
if (native_main_thread.stack_maxsize) return;
{
void* stackaddr;
size_t size;
if (get_main_stack(&stackaddr, &size) == 0) {
native_main_thread.stack_maxsize = size;
native_main_thread.stack_start = stackaddr;
goto bound_check;
}
}
#endif
#ifdef STACK_END_ADDRESS
native_main_thread.stack_start = STACK_END_ADDRESS;
#else
if (!native_main_thread.stack_start ||
STACK_UPPER((VALUE *)(void *)&addr,
native_main_thread.stack_start > (VALUE *)addr,
native_main_thread.stack_start < (VALUE *)addr)) {
native_main_thread.stack_start = (VALUE *)addr;
}
#endif
{
#if defined(HAVE_GETRLIMIT)
#if defined(PTHREAD_STACK_DEFAULT)
size_t size = PTHREAD_STACK_DEFAULT;
#else
size_t size = RUBY_VM_THREAD_VM_STACK_SIZE;
#endif
size_t space;
struct rlimit rlim;
STACK_GROW_DIR_DETECTION;
if (getrlimit(RLIMIT_STACK, &rlim) == 0) {
size = (size_t)rlim.rlim_cur;
}
addr = native_main_thread.stack_start;
if (IS_STACK_DIR_UPPER()) {
space = ((size_t)((char *)addr + size) / RB_THREAD_PAGE_SIZE) * RB_THREAD_PAGE_SIZE - (size_t)addr;
}
else {
space = (size_t)addr - ((size_t)((char *)addr - size) / RB_THREAD_PAGE_SIZE + 1) * RB_THREAD_PAGE_SIZE;
}
native_main_thread.stack_maxsize = space;
#endif
}
#if MAINSTACKADDR_AVAILABLE
bound_check:
#endif
/* If addr is out of range of main-thread stack range estimation, */
/* it should be on co-routine (alternative stack). [Feature #2294] */
{
void *start, *end;
STACK_GROW_DIR_DETECTION;
if (IS_STACK_DIR_UPPER()) {
start = native_main_thread.stack_start;
end = (char *)native_main_thread.stack_start + native_main_thread.stack_maxsize;
}
else {
start = (char *)native_main_thread.stack_start - native_main_thread.stack_maxsize;
end = native_main_thread.stack_start;
}
if ((void *)addr < start || (void *)addr > end) {
/* out of range */
native_main_thread.stack_start = (VALUE *)addr;
native_main_thread.stack_maxsize = 0; /* unknown */
}
}
}
#define CHECK_ERR(expr) \
{int err = (expr); if (err) {rb_bug_errno(#expr, err);}}
static int
native_thread_init_stack(rb_thread_t *th, void *local_in_parent_frame)
{
rb_nativethread_id_t curr = pthread_self();
#ifdef RUBY_ASAN_ENABLED
local_in_parent_frame = asan_get_real_stack_addr(local_in_parent_frame);
th->ec->machine.asan_fake_stack_handle = asan_get_thread_fake_stack_handle();
#endif
if (!native_main_thread.id) {
/* This thread is the first thread, must be the main thread -
* configure the native_main_thread object */
native_thread_init_main_thread_stack(local_in_parent_frame);
}
if (th->sched.context != NULL) {
// an M:N thread runs on the pool stack native_thread_create_shared
// recorded, whichever native thread (the main one included) hosts it.
// Not by nt->dedicated: a RESUMED hook may have pinned the nt already.
}
else if (pthread_equal(curr, native_main_thread.id)) {
th->ec->machine.stack_start = native_main_thread.stack_start;
th->ec->machine.stack_maxsize = native_main_thread.stack_maxsize;
}
else {
#ifdef STACKADDR_AVAILABLE
void *start;
size_t size;
if (get_stack(&start, &size) == 0) {
uintptr_t diff = (uintptr_t)start - (uintptr_t)local_in_parent_frame;
th->ec->machine.stack_start = local_in_parent_frame;
th->ec->machine.stack_maxsize = size - diff;
}
#else
rb_raise(rb_eNotImpError, "ruby engine can initialize only in the main thread");
#endif
}
return 0;
}
struct nt_param {
rb_vm_t *vm;
struct rb_native_thread *nt;
};
static int
native_thread_create0(struct rb_native_thread *nt)
{
int err = 0;
pthread_attr_t attr;
const size_t stack_size = nt->vm->default_params.thread_machine_stack_size;
#ifdef USE_SIGALTSTACK
nt->altstack = rb_allocate_sigaltstack();
#endif
CHECK_ERR(pthread_attr_init(&attr));
# ifdef PTHREAD_STACK_MIN
RUBY_DEBUG_LOG("stack size: %lu", (unsigned long)stack_size);
CHECK_ERR(pthread_attr_setstacksize(&attr, stack_size));
# endif
# ifdef HAVE_PTHREAD_ATTR_SETINHERITSCHED
CHECK_ERR(pthread_attr_setinheritsched(&attr, PTHREAD_INHERIT_SCHED));
# endif
CHECK_ERR(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED));
err = pthread_create(&nt->thread_id, &attr, nt_start, nt);
RUBY_DEBUG_LOG("nt:%d err:%d", (int)nt->serial, err);
CHECK_ERR(pthread_attr_destroy(&attr));
return err;
}
static void
native_thread_setup(struct rb_native_thread *nt)
{
// init cond
rb_native_cond_initialize(&nt->readyq);
// also for the main thread's nt: a zero-filled mutex is not usable on macOS
rb_native_mutex_initialize(&nt->running_th_lock);
}
static void
native_thread_setup_on_thread(struct rb_native_thread *nt)
{
// init tid
#ifdef RB_THREAD_T_HAS_NATIVE_ID
nt->tid = get_native_thread_id();
#endif
// init signal handler
RB_ALTSTACK_INIT(nt->altstack, nt->altstack);
}
static struct rb_native_thread *
native_thread_alloc(void)
{
struct rb_native_thread *nt = ZALLOC(struct rb_native_thread);
native_thread_setup(nt);
#if USE_MN_THREADS
nt->nt_context = ruby_xmalloc(sizeof(struct coroutine_context));
#endif
#if USE_RUBY_DEBUG_LOG
static rb_atomic_t nt_serial = 2;
nt->serial = RUBY_ATOMIC_FETCH_ADD(nt_serial, 1);
#endif
return nt;
}
#if USE_NATIVE_THREAD_PRIORITY
static void
native_thread_apply_priority(rb_thread_t *th)
{
#if defined(_POSIX_PRIORITY_SCHEDULING) && (_POSIX_PRIORITY_SCHEDULING > 0)
struct sched_param sp;
int policy;
int priority = 0 - th->priority;
int max, min;
pthread_getschedparam(th->nt->thread_id, &policy, &sp);
max = sched_get_priority_max(policy);
min = sched_get_priority_min(policy);
if (min > priority) {
priority = min;
}
else if (max < priority) {
priority = max;
}
sp.sched_priority = priority;
pthread_setschedparam(th->nt->thread_id, policy, &sp);
#else
/* not touched */
#endif
}
#endif /* USE_NATIVE_THREAD_PRIORITY */
static int
native_fd_select(int n, rb_fdset_t *readfds, rb_fdset_t *writefds, rb_fdset_t *exceptfds, struct timeval *timeout, rb_thread_t *th)
{
return rb_fd_select(n, readfds, writefds, exceptfds, timeout);
}
/*
* Send a signal to make the target thread return from a blocking syscall.
* Maybe any signal is ok, but we chose SIGVTALRM (see null_func).
*/
static void
native_thread_interrupt(rb_thread_t *th)
{
pthread_kill(th->nt->thread_id, SIGVTALRM);
}
static int
native_thread_default_max_cpu(void)
{
#if defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_ONLN)
long nprocessors = sysconf(_SC_NPROCESSORS_ONLN);
return (nprocessors > 0) ? (int)nprocessors : 8;
#else
return 8;
#endif
}
#define TT_DEBUG 0
#define WRITE_CONST(fd, str) (void)(write((fd),(str),sizeof(str)-1)<0)
void
rb_thread_wakeup_timer_thread(int sig)
{
// This function can be called from signal handlers so that
// pthread_mutex_lock() should not be used.
// wakeup timer thread
timer_thread_wakeup_force();
// interrupt main thread if main thread is available
if (RUBY_ATOMIC_LOAD(system_working)) {
rb_vm_t *vm = GET_VM();
rb_thread_t *main_th = vm->ractor.main_thread;
if (main_th) {
volatile rb_execution_context_t *main_th_ec = ACCESS_ONCE(rb_execution_context_t *, main_th->ec);
if (main_th_ec) {
RUBY_VM_SET_TRAP_INTERRUPT(main_th_ec);
if (vm->ubf_async_safe && main_th->unblock.func) {
(main_th->unblock.func)(main_th->unblock.arg);
}
}
}
}
}
#define CLOSE_INVALIDATE_PAIR(expr) \
close_invalidate_pair(expr,"close_invalidate: "#expr)
static void
close_invalidate(int *fdp, const char *msg)
{
int fd = *fdp;
*fdp = -1;
if (close(fd) < 0) {
async_bug_fd(msg, errno, fd);
}
}
static void
close_invalidate_pair(int fds[2], const char *msg)
{
if (USE_EVENTFD && fds[0] == fds[1]) {
fds[1] = -1; // disable write port first
close_invalidate(&fds[0], msg);
}
else {
close_invalidate(&fds[1], msg);
close_invalidate(&fds[0], msg);
}
}
static void
set_nonblock(int fd)
{
int oflags;
int err;
oflags = fcntl(fd, F_GETFL);
if (oflags == -1)
rb_sys_fail(0);
oflags |= O_NONBLOCK;
err = fcntl(fd, F_SETFL, oflags);
if (err == -1)
rb_sys_fail(0);
}
/* communication pipe with timer thread and signal handler */
static void
setup_communication_pipe_internal(int pipes[2])
{
int err;
if (pipes[0] > 0 || pipes[1] > 0) {
VM_ASSERT(pipes[0] > 0);
VM_ASSERT(pipes[1] > 0);
return;
}
/*
* Don't bother with eventfd on ancient Linux 2.6.22..2.6.26 which were
* missing EFD_* flags, they can fall back to pipe
*/
#if USE_EVENTFD && defined(EFD_NONBLOCK) && defined(EFD_CLOEXEC)
pipes[0] = pipes[1] = eventfd(0, EFD_NONBLOCK|EFD_CLOEXEC);
if (pipes[0] >= 0) {
rb_update_max_fd(pipes[0]);
return;
}
#endif
err = rb_cloexec_pipe(pipes);
if (err != 0) {
rb_bug("can not create communication pipe");
}
rb_update_max_fd(pipes[0]);
rb_update_max_fd(pipes[1]);
set_nonblock(pipes[0]);
set_nonblock(pipes[1]);
}
#if !defined(SET_CURRENT_THREAD_NAME) && defined(__linux__) && defined(PR_SET_NAME)
# define SET_CURRENT_THREAD_NAME(name) prctl(PR_SET_NAME, name)
#endif
enum {
THREAD_NAME_MAX =
#if defined(__linux__)
16
#elif defined(__APPLE__)
/* Undocumented, and main thread seems unlimited */
64
#else
16
#endif
};
static VALUE threadptr_invoke_proc_location(rb_thread_t *th);
static void
native_set_thread_name(rb_thread_t *th)
{
#ifdef SET_CURRENT_THREAD_NAME
VALUE loc;
// An M:N thread does not own the native thread it runs on: naming it here
// would name whichever nt started it (under RUBY_MN_THREADS=2 that can be
// the process's main one, whose name is the process's). Thread#name= is
// skipped for the same reason (rb_thread_setname).
if (!th->has_dedicated_nt) return;
if (!NIL_P(loc = th->name)) {
SET_CURRENT_THREAD_NAME(RSTRING_PTR(loc));
}
else if ((loc = threadptr_invoke_proc_location(th)) != Qnil) {
char *name, *p;
char buf[THREAD_NAME_MAX];
size_t len;
int n;
name = RSTRING_PTR(RARRAY_AREF(loc, 0));
p = strrchr(name, '/'); /* show only the basename of the path. */
if (p && p[1])
name = p + 1;
n = snprintf(buf, sizeof(buf), "%s:%d", name, NUM2INT(RARRAY_AREF(loc, 1)));
RB_GC_GUARD(loc);
len = (size_t)n;
if (len >= sizeof(buf)) {
buf[sizeof(buf)-2] = '*';
buf[sizeof(buf)-1] = '\0';
}
SET_CURRENT_THREAD_NAME(buf);
}
#endif
}
static void
native_set_another_thread_name(rb_nativethread_id_t thread_id, VALUE name)
{
#if defined SET_ANOTHER_THREAD_NAME || defined SET_CURRENT_THREAD_NAME
char buf[THREAD_NAME_MAX];
const char *s = "";
# if !defined SET_ANOTHER_THREAD_NAME
if (!pthread_equal(pthread_self(), thread_id)) return;
# endif
if (!NIL_P(name)) {
rb_len_t n;
RSTRING_GETMEM(name, s, n);
if (n >= (int)sizeof(buf)) {
memcpy(buf, s, sizeof(buf)-1);
buf[sizeof(buf)-1] = '\0';
s = buf;
}
}
# if defined SET_ANOTHER_THREAD_NAME
SET_ANOTHER_THREAD_NAME(thread_id, s);
# elif defined SET_CURRENT_THREAD_NAME
SET_CURRENT_THREAD_NAME(s);
# endif
#endif
}
#if defined(RB_THREAD_T_HAS_NATIVE_ID) || defined(__APPLE__)
static VALUE
native_thread_native_thread_id(rb_thread_t *target_th)
{
if (!target_th->nt) return Qnil;
#ifdef RB_THREAD_T_HAS_NATIVE_ID
int tid = target_th->nt->tid;
if (tid == 0) return Qnil;
return INT2FIX(tid);
#elif defined(__APPLE__)
uint64_t tid;
int e = pthread_threadid_np(target_th->nt->thread_id, &tid);
if (e != 0) rb_syserr_fail(e, "pthread_threadid_np");
return ULL2NUM((unsigned long long)tid);
#endif
}
# define USE_NATIVE_THREAD_NATIVE_THREAD_ID 1
#else
# define USE_NATIVE_THREAD_NATIVE_THREAD_ID 0
#endif
static struct {
rb_serial_t created_fork_gen;
pthread_t pthread_id;
int comm_fds[2]; // r, w
#if (HAVE_SYS_EPOLL_H || HAVE_SYS_EVENT_H) && USE_MN_THREADS
int event_fd; // kernel event queue fd (epoll/kqueue)
#endif
#if HAVE_SYS_EPOLL_H && USE_MN_THREADS
#define EPOLL_EVENTS_MAX 0x10
struct epoll_event finished_events[EPOLL_EVENTS_MAX];
#elif HAVE_SYS_EVENT_H && USE_MN_THREADS
#define KQUEUE_EVENTS_MAX 0x10
struct kevent finished_events[KQUEUE_EVENTS_MAX];
#endif
#if USE_MN_THREADS
/* Timed waiters, bucketed by deadline into a hierarchical timer wheel;
* untimed (fd-only) waiters keep a plain list. Both under waiting_lock.
* The wheel operations all live in thread_sched_mn.c (timer_wheel_*). */
#define TIMER_WHEEL_LEVELS 4
#define TIMER_WHEEL_SLOT_BITS 6
#define TIMER_WHEEL_SLOTS (1 << TIMER_WHEEL_SLOT_BITS)
struct timer_wheel_level {
uint64_t occupied; // bit s: slots[s] is non-empty
struct ccan_list_head slots[TIMER_WHEEL_SLOTS];
} wheel[TIMER_WHEEL_LEVELS];
uint64_t wheel_cursor_tick; // slots for ticks <= this are drained
rb_hrtime_t next_expiry; // never later than the earliest deadline
pthread_mutex_t waiting_lock; // the wheel and the flags of fd-less timed waits
/* The fd map entries and the flags of io waits are guarded per fd by a
* shard lock, so unrelated fds register and wake in parallel. Whoever
* clears an io wait's flags under its shard owns the wakeup. Lock order:
* shard -> waiting_lock -> wake_pending_lock, never the other way. */
#define IO_WAIT_SHARDS 16
pthread_mutex_t fd_shard_locks[IO_WAIT_SHARDS];
// signaled when wake_pending clears on a thread; see timer_thread_wake_fence
pthread_mutex_t wake_pending_lock;
rb_nativethread_cond_t wake_pending_cond;
#endif
#if (HAVE_SYS_EPOLL_H || HAVE_SYS_EVENT_H) && USE_MN_THREADS
// fd -> struct rb_fd_waiters, in chunks so entries never move. The chunk
// table installs slots by CAS (chunks span shards); entry state is guarded
// by the fd's shard lock.
#define FDMAP_MAX_CHUNKS 1024 // fds up to FDMAP_MAX_CHUNKS * FDMAP_CHUNK_SIZE
struct rb_fd_waiters *fdmap_chunks[FDMAP_MAX_CHUNKS];
#endif
} timer_th = {
.created_fork_gen = 0,
};
#define TIMER_THREAD_CREATED_P() (timer_th.created_fork_gen == current_fork_gen)
static void timer_thread_check_timeslice(rb_vm_t *vm);
static bool timeslice_scan(rb_vm_t *vm, bool interrupt);
static int timer_thread_set_timeout(rb_vm_t *vm);
#include "thread_sched_mn.c"
/* only use signal-safe system calls here */
static void
signal_communication_pipe(int fd)
{
#if USE_EVENTFD
const uint64_t buff = 1;
#else
const char buff = '!';
#endif
ssize_t result;
/* already opened */
if (fd >= 0) {
retry:
if ((result = write(fd, &buff, sizeof(buff))) <= 0) {
int e = errno;
switch (e) {
case EINTR: goto retry;
case EAGAIN:
#if defined(EWOULDBLOCK) && EWOULDBLOCK != EAGAIN
case EWOULDBLOCK:
#endif
break;
default:
async_bug_fd("rb_thread_wakeup_timer_thread: write", e, fd);
}
}
if (TT_DEBUG) WRITE_CONST(2, "rb_thread_wakeup_timer_thread: write\n");
}
else {
// ignore wakeup
}
}
static void
timer_thread_wakeup_force(void)
{
// should not use RUBY_DEBUG_LOG() because it can be called within signal handlers.
signal_communication_pipe(timer_th.comm_fds[1]);
}
static void
rb_thread_create_timer_thread(void)
{
rb_serial_t created_fork_gen = timer_th.created_fork_gen;
RUBY_DEBUG_LOG("fork_gen create:%d current:%d", (int)created_fork_gen, (int)current_fork_gen);
timer_th.created_fork_gen = current_fork_gen;
if (created_fork_gen != current_fork_gen) {
if (created_fork_gen != 0) {
RUBY_DEBUG_LOG("forked child process");
CLOSE_INVALIDATE_PAIR(timer_th.comm_fds);
#if USE_MN_THREADS
// The parent's waiters do not exist in the child, and the armings
// belong to the closed event backend: a stale entry would satisfy
// fd_waiters_arm's want == armed_flags check and never arm the new
// backend (a lost wake the old dynamic map also had).
for (unsigned int ci = 0; ci < FDMAP_MAX_CHUNKS; ci++) {
struct rb_fd_waiters *chunk = timer_th.fdmap_chunks[ci];
if (chunk == NULL) continue;
for (unsigned int i = 0; i < FDMAP_CHUNK_SIZE; i++) {
ccan_list_head_init(&chunk[i].waiters);
chunk[i].armed_flags = 0;
chunk[i].generation++;
}
}
#endif
#if HAVE_SYS_EPOLL_H && USE_MN_THREADS
close_invalidate(&timer_th.event_fd, "close event_fd");
#elif HAVE_SYS_EVENT_H && USE_MN_THREADS
// A kqueue is not inherited across fork: the number names a closed
// fd in the child, and closing it could hit a reused one.
timer_th.event_fd = -1;
#endif
// No mutex_destroy for waiting_lock: glibc returns EBUSY (and
// rb_native_mutex_destroy rb_bugs) for a mutex another ractor's
// M:N thread held at the fork moment. The initialize below
// starts over.
}
#if USE_MN_THREADS
for (int lvl = 0; lvl < TIMER_WHEEL_LEVELS; lvl++) {
timer_th.wheel[lvl].occupied = 0;
for (int slot = 0; slot < TIMER_WHEEL_SLOTS; slot++) {
ccan_list_head_init(&timer_th.wheel[lvl].slots[slot]);
}
}
timer_th.wheel_cursor_tick = timer_wheel_tick(rb_hrtime_now());
timer_th.next_expiry = TIMER_WHEEL_NO_EXPIRY;
rb_native_mutex_initialize(&timer_th.waiting_lock);
for (int i = 0; i < IO_WAIT_SHARDS; i++) {
rb_native_mutex_initialize(&timer_th.fd_shard_locks[i]);
}
rb_native_mutex_initialize(&timer_th.wake_pending_lock);
rb_native_cond_initialize(&timer_th.wake_pending_cond);
#endif
// open communication channel
setup_communication_pipe_internal(timer_th.comm_fds);
// open event fd
timer_thread_setup_mn();
}
int err = pthread_create(&timer_th.pthread_id, NULL, timer_thread_func, GET_VM());
if (err != 0) {
// The timer thread delivers signals and drives the M:N scheduler;
// running without one only defers the failure to stranger places.
rb_bug_errno("pthread_create (timer thread)", err);
}
}
static int
native_stop_timer_thread(void)
{
RUBY_ATOMIC_SET(system_working, 0);
RUBY_DEBUG_LOG("wakeup send %d", timer_th.comm_fds[1]);
timer_thread_wakeup_force();
RUBY_DEBUG_LOG("wakeup sent");
pthread_join(timer_th.pthread_id, NULL);
if (TT_DEBUG) fprintf(stderr, "stop timer thread\n");
return 1;
}
static void
native_reset_timer_thread(void)
{
//
}
#ifdef HAVE_SIGALTSTACK
int
ruby_stack_overflowed_p(const rb_thread_t *th, const void *addr)
{
void *base;
size_t size;
const size_t water_mark = RB_THREAD_PAGE_SIZE;
STACK_GROW_DIR_DETECTION;
if (th) {
size = th->ec->machine.stack_maxsize;
base = (char *)th->ec->machine.stack_start - STACK_DIR_UPPER(0, size);
}
#ifdef STACKADDR_AVAILABLE
else if (get_stack(&base, &size) == 0) {
# ifdef __APPLE__
// th is NULL in this branch; ask about the calling thread itself.
if (pthread_equal(pthread_self(), native_main_thread.id)) {
struct rlimit rlim;
if (getrlimit(RLIMIT_STACK, &rlim) == 0 && rlim.rlim_cur > size) {
size = (size_t)rlim.rlim_cur;
}
}
# endif
base = (char *)base + STACK_DIR_UPPER(+size, -size);
}
#endif
else {
return 0;
}
if (size > water_mark) size = water_mark;
if (IS_STACK_DIR_UPPER()) {
if (size > ~(size_t)base+1) size = ~(size_t)base+1;
if (addr > base && addr <= (void *)((char *)base + size)) return 1;
}
else {
if (size > (size_t)base) size = (size_t)base;
if (addr > (void *)((char *)base - size) && addr <= base) return 1;
}
return 0;
}
#endif
int
rb_reserved_fd_p(int fd)
{
/* no false-positive if out-of-FD at startup */
if (fd < 0) return 0;
if (fd == timer_th.comm_fds[0] ||
fd == timer_th.comm_fds[1]
#if (HAVE_SYS_EPOLL_H || HAVE_SYS_EVENT_H) && USE_MN_THREADS
|| fd == timer_th.event_fd
#endif
) {
goto check_fork_gen;
}
return 0;
check_fork_gen:
if (timer_th.created_fork_gen == current_fork_gen) {
/* async-signal-safe */
return 1;
}
else {
return 0;
}
}
rb_nativethread_id_t
rb_nativethread_self(void)
{
return pthread_self();
}
#if defined(USE_POLL) && !defined(HAVE_PPOLL)
/* TODO: don't ignore sigmask */
static int
ruby_ppoll(struct pollfd *fds, nfds_t nfds,
const struct timespec *ts, const sigset_t *sigmask)
{
int timeout_ms;
if (ts) {
int tmp, tmp2;
if (ts->tv_sec > INT_MAX/1000)
timeout_ms = INT_MAX;
else {
tmp = (int)(ts->tv_sec * 1000);
/* round up 1ns to 1ms to avoid excessive wakeups for <1ms sleep */
tmp2 = (int)((ts->tv_nsec + 999999L) / (1000L * 1000L));
if (INT_MAX - tmp < tmp2)
timeout_ms = INT_MAX;
else
timeout_ms = (int)(tmp + tmp2);
}
}
else
timeout_ms = -1;
return poll(fds, nfds, timeout_ms);
}
# define ppoll(fds,nfds,ts,sigmask) ruby_ppoll((fds),(nfds),(ts),(sigmask))
#endif
// fork read-write lock (only for pthread)
static pthread_rwlock_t rb_thread_fork_rw_lock = PTHREAD_RWLOCK_INITIALIZER;
// the registered thread waiting to be joined, or NULL; no pthread_t is 0
static void *last_exiting_thread;
STATIC_ASSERT(pthread_t_fits_in_pointer, sizeof(pthread_t) <= sizeof(void *));
void
rb_thread_release_fork_lock(void)
{
int r;
if ((r = pthread_rwlock_unlock(&rb_thread_fork_rw_lock))) {
rb_bug_errno("pthread_rwlock_unlock", r);
}
}
void
rb_thread_reset_fork_lock(void)
{
// On macOS the child's copy still counts a thread waiting for this lock
// at fork: unlocking it leaves kernel state that later waiters hang on,
// and destroying or initializing it fails with EBUSY.
rb_thread_fork_rw_lock = (pthread_rwlock_t)PTHREAD_RWLOCK_INITIALIZER;
}
void *
rb_thread_prevent_fork(void *(*func)(void *), void *data)
{
int r;
if ((r = pthread_rwlock_rdlock(&rb_thread_fork_rw_lock))) {
rb_bug_errno("pthread_rwlock_rdlock", r);
}
void *result = func(data);
rb_thread_release_fork_lock();
return result;
}
static void
thread_register_exiting(void *thread)
{
void *previous_thread = RUBY_ATOMIC_PTR_EXCHANGE(last_exiting_thread, thread);
if (previous_thread) {
int r;
if ((r = pthread_join((pthread_t)(uintptr_t)previous_thread, NULL))) {
rb_bug_errno("pthread_join", r);
}
}
}
// Called within rb_thread_prevent_fork() by a joinable thread just before it
// exits. The thread it replaces in the slot has usually exited by then.
void
rb_thread_register_exiting(void)
{
thread_register_exiting((void *)(uintptr_t)pthread_self());
}
void
rb_thread_acquire_fork_lock(void)
{
int r;
if ((r = pthread_rwlock_wrlock(&rb_thread_fork_rw_lock))) {
rb_bug_errno("pthread_rwlock_wrlock", r);
}
// A registered thread may still be exiting, and glibc's thread exit takes
// the resolver configuration lock, which fork does not reset. None can
// register while this lock is held.
thread_register_exiting(NULL);
}
// thread internal event hooks (only for pthread)
struct rb_internal_thread_event_hook {
rb_internal_thread_event_callback callback;
rb_event_flag_t event;
void *user_data;
struct rb_internal_thread_event_hook *next;
};
static pthread_rwlock_t rb_internal_thread_event_hooks_rw_lock = PTHREAD_RWLOCK_INITIALIZER;
/* For the GC: whether any thread-event hook is registered right now. The rwlock
* makes the answer happen-after any completed registration; a hook registered
* after this read gets no event from the asking thread (rb_thread_execute_hooks
* skips a swept thread), so it never sees the objects the caller may collect. */
bool
rb_thread_event_hooks_registered_p(void)
{
int r;
if ((r = pthread_rwlock_rdlock(&rb_internal_thread_event_hooks_rw_lock))) {
rb_bug_errno("pthread_rwlock_rdlock", r);
}
const bool registered = (rb_internal_thread_event_hooks != NULL);
if ((r = pthread_rwlock_unlock(&rb_internal_thread_event_hooks_rw_lock))) {
rb_bug_errno("pthread_rwlock_unlock", r);
}
return registered;
}
#if defined(HAVE_WORKING_FORK)
static void
rb_internal_thread_event_hooks_rw_lock_atfork(void)
{
// After fork(), this rwlock may have been held by a now-dead thread.
//
// pthread_rwlock_destroy() on a held lock is undefined behavior, and
// pthread_rwlock_init() on an already-initialized lock is also undefined
// behavior
//
// Direct assignment of PTHREAD_RWLOCK_INITIALIZER is safe and portable.
rb_internal_thread_event_hooks_rw_lock =
(pthread_rwlock_t)PTHREAD_RWLOCK_INITIALIZER;
}
#endif
rb_internal_thread_event_hook_t *
rb_internal_thread_add_event_hook(rb_internal_thread_event_callback callback, rb_event_flag_t internal_event, void *user_data)
{
rb_internal_thread_event_hook_t *hook = ALLOC_N(rb_internal_thread_event_hook_t, 1);
hook->callback = callback;
hook->user_data = user_data;
hook->event = internal_event;
int r;
if ((r = pthread_rwlock_wrlock(&rb_internal_thread_event_hooks_rw_lock))) {
rb_bug_errno("pthread_rwlock_wrlock", r);
}
hook->next = rb_internal_thread_event_hooks;
ATOMIC_PTR_EXCHANGE(rb_internal_thread_event_hooks, hook);
if ((r = pthread_rwlock_unlock(&rb_internal_thread_event_hooks_rw_lock))) {
rb_bug_errno("pthread_rwlock_unlock", r);
}
return hook;
}
bool
rb_internal_thread_remove_event_hook(rb_internal_thread_event_hook_t * hook)
{
int r;
if ((r = pthread_rwlock_wrlock(&rb_internal_thread_event_hooks_rw_lock))) {
rb_bug_errno("pthread_rwlock_wrlock", r);
}
bool success = FALSE;
if (rb_internal_thread_event_hooks == hook) {
ATOMIC_PTR_EXCHANGE(rb_internal_thread_event_hooks, hook->next);
success = TRUE;
}
else {
rb_internal_thread_event_hook_t *h = rb_internal_thread_event_hooks;
do {
if (h->next == hook) {
h->next = hook->next;
success = TRUE;
break;
}
} while ((h = h->next));
}
if ((r = pthread_rwlock_unlock(&rb_internal_thread_event_hooks_rw_lock))) {
rb_bug_errno("pthread_rwlock_unlock", r);
}
if (success) {
SIZED_FREE(hook);
}
return success;
}
static void
rb_thread_execute_hooks(rb_event_flag_t event, rb_thread_t *th)
{
int r;
/* th->self == 0: the dying thread's final collection swept its Thread wrapper, so
* no hook existed then; one registered since has no ordering claim to this event. */
if (th->self == 0) return;
if ((r = pthread_rwlock_rdlock(&rb_internal_thread_event_hooks_rw_lock))) {
rb_bug_errno("pthread_rwlock_rdlock", r);
}
if (rb_internal_thread_event_hooks) {
rb_internal_thread_event_hook_t *h = rb_internal_thread_event_hooks;
do {
if (h->event & event) {
rb_internal_thread_event_data_t event_data = {
.thread = th->self,
};
(*h->callback)(event, &event_data, h->user_data);
}
} while((h = h->next));
}
if ((r = pthread_rwlock_unlock(&rb_internal_thread_event_hooks_rw_lock))) {
rb_bug_errno("pthread_rwlock_unlock", r);
}
}
#endif /* THREAD_SYSTEM_DEPENDENT_IMPLEMENTATION */
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