mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 19:43:32 +00:00
e522aa3a07
- ASAN memory morgue is now lockless - Make C11 atomics header more portable - Rewrote pthread keys support to be lockless - Simplify Python's unicode table unpacking code - Make crash report write(2) closer to being atomic - Make it possible to strace/ftrace a single thread - ASAN now checks nul-terminated strings fast and properly - Windows fork() now restores TLS memory of calling thread
85 lines
3.8 KiB
C
85 lines
3.8 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
|
|
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
|
|
╞══════════════════════════════════════════════════════════════════════════════╡
|
|
│ Copyright 2022 Justine Alexandra Roberts Tunney │
|
|
│ │
|
|
│ Permission to use, copy, modify, and/or distribute this software for │
|
|
│ any purpose with or without fee is hereby granted, provided that the │
|
|
│ above copyright notice and this permission notice appear in all copies. │
|
|
│ │
|
|
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
|
|
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
|
|
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
|
|
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
|
|
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
|
|
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
|
|
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
|
|
│ PERFORMANCE OF THIS SOFTWARE. │
|
|
╚─────────────────────────────────────────────────────────────────────────────*/
|
|
#include "libc/intrin/weaken.h"
|
|
#include "libc/thread/posixthread.internal.h"
|
|
#include "libc/thread/thread.h"
|
|
|
|
/**
|
|
* Registers fork() handlers.
|
|
*
|
|
* Parent and child functions are called in the same order they're
|
|
* registered. Prepare functions are called in reverse order.
|
|
*
|
|
* Here's an example of how pthread_atfork() can be used:
|
|
*
|
|
* static struct {
|
|
* pthread_once_t once;
|
|
* pthread_mutex_t lock;
|
|
* // data structures...
|
|
* } g_lib;
|
|
*
|
|
* static void lib_lock(void) {
|
|
* pthread_mutex_lock(&g_lib.lock);
|
|
* }
|
|
*
|
|
* static void lib_unlock(void) {
|
|
* pthread_mutex_unlock(&g_lib.lock);
|
|
* }
|
|
*
|
|
* static void lib_funlock(void) {
|
|
* pthread_mutex_init(&g_lib.lock, 0);
|
|
* }
|
|
*
|
|
* static void lib_setup(void) {
|
|
* lib_funlock();
|
|
* pthread_atfork(lib_lock, lib_unlock, lib_funlock);
|
|
* }
|
|
*
|
|
* static void lib_init(void) {
|
|
* pthread_once(&g_lib.once, lib_setup);
|
|
* }
|
|
*
|
|
* void lib(void) {
|
|
* lib_init();
|
|
* lib_lock();
|
|
* // do stuff...
|
|
* lib_unlock();
|
|
* }
|
|
*
|
|
* This won't actually aspect fork() until pthread_create() is called,
|
|
* since we don't want normal non-threaded programs to have to acquire
|
|
* exclusive locks on every resource in the entire app just to fork().
|
|
*
|
|
* The vfork() function is *never* aspected. What happens instead is a
|
|
* global variable named `__vforked` is set to true in the child which
|
|
* causes lock functions to do nothing. So far, it works like a charm.
|
|
*
|
|
* @param prepare is run by fork() before forking happens
|
|
* @param parent is run by fork() after forking happens in parent process
|
|
* @param child is run by fork() after forking happens in childe process
|
|
* @return 0 on success, or errno on error
|
|
* @raise ENOMEM if we require more vespene gas
|
|
*/
|
|
int pthread_atfork(atfork_f prepare, atfork_f parent, atfork_f child) {
|
|
if (_weaken(_pthread_atfork)) {
|
|
return _weaken(_pthread_atfork)(prepare, parent, child);
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|