cosmopolitan/libc/runtime/daemon.c
Justine Tunney b41f91c658
Greatly expand system() shell code features
The cosmopolitan command interpreter now has 13 builtin commands,
variable support, support for ; / && / || syntax, asynchronous support,
and plenty of unit tests with bug fixes.

This change fixes a bug in posix_spawn() with null envp arg. strace
logging now uses atomic writes for scatter functions. Breaking change
renaming GetCpuCount() to _getcpucount(). TurfWar is now updated to use
the new token bucket algorithm. WIN32 affinity masks now inherit across
fork() and execve().
2022-10-11 21:30:31 -07:00

68 lines
2.8 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/assert.h"
#include "libc/calls/calls.h"
#include "libc/calls/syscall_support-sysv.internal.h"
#include "libc/dce.h"
#include "libc/nt/enum/processcreationflags.h"
#include "libc/paths.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/consts/o.h"
/**
* Runs process in background.
*
* On Unix this calls fork() and setsid(). On Windows this is
* implemented using CreateProcess(kNtDetachedProcess).
*
* @return 0 on success, or -1 w/ errno
*/
int daemon(int nochdir, int noclose) {
int fd;
switch (_fork(kNtDetachedProcess)) {
case -1:
return -1;
case 0:
break;
default:
_Exit(0);
}
if (!IsWindows()) {
if (setsid() == -1) {
return -1;
}
}
if (!nochdir) {
_unassert(!chdir("/"));
}
if (!noclose && (fd = open(_PATH_DEVNULL, O_RDWR)) != -1) {
_unassert(dup2(fd, 0) == 0);
_unassert(dup2(fd, 1) == 1);
_unassert(dup2(fd, 2) == 2);
if (fd > 2) {
_unassert(!close(fd));
}
}
return 0;
}