cosmopolitan/libc/proc/fork.c
Jōshin e16a7d8f3b
flip et / noet in modelines
`et` means `expandtab`.

```sh
rg 'vi: .* :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\)  :vi/vi: \1 xoet\2:vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2  :vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/'
```
2023-12-07 22:17:11 -05:00

127 lines
5.2 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et 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/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/dll.h"
#include "libc/intrin/strace.internal.h"
#include "libc/intrin/weaken.h"
#include "libc/nt/files.h"
#include "libc/nt/process.h"
#include "libc/nt/runtime.h"
#include "libc/nt/synchronization.h"
#include "libc/nt/thread.h"
#include "libc/proc/proc.internal.h"
#include "libc/runtime/internal.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/syslib.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 Dll *e;
int ax, dx, tid, parent;
parent = __pid;
BLOCK_SIGNALS;
if (IsWindows()) __proc_lock();
if (__threaded && _weaken(_pthread_onfork_prepare)) {
_weaken(_pthread_onfork_prepare)();
}
if (!IsWindows()) {
ax = sys_fork();
} else {
ax = sys_fork_nt(dwCreationFlags);
}
if (!ax) {
// get new process id
if (!IsWindows()) {
dx = sys_getpid().ax;
} else {
dx = GetCurrentProcessId();
}
__pid = dx;
// turn other threads into zombies
// we can't free() them since we're monopolizing all locks
// we assume the operating system already reclaimed system handles
struct CosmoTib *tib = __get_tls();
struct PosixThread *pt = (struct PosixThread *)tib->tib_pthread;
dll_remove(&_pthread_list, &pt->list);
for (e = dll_first(_pthread_list); e; e = dll_next(_pthread_list, e)) {
atomic_store_explicit(&POSIXTHREAD_CONTAINER(e)->pt_status,
kPosixThreadZombie, memory_order_relaxed);
atomic_store_explicit(&POSIXTHREAD_CONTAINER(e)->tib->tib_syshand, 0,
memory_order_relaxed);
}
dll_make_first(&_pthread_list, &pt->list);
// get new main thread id
tid = IsLinux() || IsXnuSilicon() ? dx : sys_gettid();
atomic_store_explicit(&tib->tib_tid, tid, memory_order_relaxed);
atomic_store_explicit(&pt->ptid, tid, memory_order_relaxed);
// get new system thread handle
intptr_t syshand = 0;
if (IsXnuSilicon()) {
syshand = __syslib->__pthread_self();
} else if (IsWindows()) {
DuplicateHandle(GetCurrentProcess(), GetCurrentThread(),
GetCurrentProcess(), &syshand, 0, false,
kNtDuplicateSameAccess);
}
atomic_store_explicit(&tib->tib_syshand, syshand, memory_order_relaxed);
// we can't be canceled if the canceler no longer exists
atomic_store_explicit(&pt->pt_canceled, false, memory_order_relaxed);
// run user fork callbacks
if (__threaded && _weaken(_pthread_onfork_child)) {
_weaken(_pthread_onfork_child)();
}
STRACE("fork() → 0 (child of %d)", parent);
} else {
// this is the parent process
if (__threaded && _weaken(_pthread_onfork_parent)) {
_weaken(_pthread_onfork_parent)();
}
if (IsWindows()) __proc_unlock();
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
*/
int fork(void) {
return _fork(0);
}