cosmopolitan/libc/runtime/fork.c
Justine Tunney b407327972
Make fixes and improvements
- clock_nanosleep() is now much faster on OpenBSD and NetBSD
- Thread joining is now much faster on NetBSD
- FreeBSD timestamps are now more accurate
- Thread spawning now goes faster on XNU
- Clean up the clone() code
2022-11-08 10:11:46 -08:00

91 lines
3.7 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 2020 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/assert.h"
#include "libc/calls/blocksigs.internal.h"
#include "libc/calls/calls.h"
#include "libc/calls/struct/sigset.h"
#include "libc/calls/struct/sigset.internal.h"
#include "libc/calls/syscall-nt.internal.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/dce.h"
#include "libc/intrin/atomic.h"
#include "libc/intrin/strace.internal.h"
#include "libc/intrin/weaken.h"
#include "libc/nt/process.h"
#include "libc/runtime/internal.h"
#include "libc/sysv/consts/sig.h"
#include "libc/thread/posixthread.internal.h"
#include "libc/thread/tls.h"
int _fork(uint32_t dwCreationFlags) {
struct CosmoTib *tib;
struct PosixThread *pt;
int ax, dx, tid, parent;
BLOCK_SIGNALS;
if (__threaded && _weaken(_pthread_onfork_prepare)) {
_weaken(_pthread_onfork_prepare)();
}
if (!IsWindows()) {
ax = sys_fork();
} else {
ax = sys_fork_nt(dwCreationFlags);
}
if (!ax) {
if (!IsWindows()) {
dx = sys_getpid().ax;
} else {
dx = GetCurrentProcessId();
}
parent = __pid;
__pid = dx;
if (__tls_enabled) {
tib = __get_tls();
tid = IsLinux() ? dx : sys_gettid();
atomic_store_explicit(&tib->tib_tid, tid, memory_order_relaxed);
if ((pt = (struct PosixThread *)tib->tib_pthread)) {
atomic_store_explicit(&pt->ptid, tid, memory_order_relaxed);
}
}
if (__threaded && _weaken(_pthread_onfork_child)) {
_weaken(_pthread_onfork_child)();
}
STRACE("fork() → 0 (child of %d)", parent);
} else {
if (__threaded && _weaken(_pthread_onfork_parent)) {
_weaken(_pthread_onfork_parent)();
}
STRACE("fork() → %d% m", ax);
}
ALLOW_SIGNALS;
return ax;
}
/**
* Creates new process.
*
* @return 0 to child, child pid to parent, or -1 w/ errno
* @raise EAGAIN if `RLIMIT_NPROC` was exceeded or system lacked resources
* @raise ENOMEM if we require more vespene gas
* @asyncsignalsafe
* @threadsafe
*/
int fork(void) {
return _fork(0);
}