16545cf5d5
The daemonfd function is equivalent to the daemon(3) function expect that arguments are descriptors. For example dhclient(8) which is sandboxed is unable to open /dev/null to close stdio instead it's allows to fail daemon(3) function to close the descriptors and then do it explicit in code. Instead of such hacks we can use now daemonfd. This API can be also helpful to migrate system to platforms like CheriBSD. Reviewed by: brooks@, bcr@, jilles@ (earlier version) Differential Revision: https://reviews.freebsd.org/D13433
122 lines
3.2 KiB
C
122 lines
3.2 KiB
C
/*-
|
|
* SPDX-License-Identifier: BSD-3-Clause
|
|
*
|
|
* Copyright (c) 1990, 1993 The Regents of the University of California.
|
|
* Copyright (c) 2017 Mariusz Zaborski <oshogbo@FreeBSD.org>
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#if defined(LIBC_SCCS) && !defined(lint)
|
|
static char sccsid[] = "@(#)daemon.c 8.1 (Berkeley) 6/4/93";
|
|
#endif /* LIBC_SCCS and not lint */
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include "namespace.h"
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <paths.h>
|
|
#include <stdlib.h>
|
|
#include <signal.h>
|
|
#include <unistd.h>
|
|
#include "un-namespace.h"
|
|
#include "libc_private.h"
|
|
|
|
int
|
|
daemonfd(int chdirfd, int nullfd)
|
|
{
|
|
struct sigaction osa, sa;
|
|
pid_t newgrp;
|
|
int oerrno;
|
|
int osa_ok;
|
|
|
|
/* A SIGHUP may be thrown when the parent exits below. */
|
|
sigemptyset(&sa.sa_mask);
|
|
sa.sa_handler = SIG_IGN;
|
|
sa.sa_flags = 0;
|
|
osa_ok = __libc_sigaction(SIGHUP, &sa, &osa);
|
|
|
|
switch (fork()) {
|
|
case -1:
|
|
return (-1);
|
|
case 0:
|
|
break;
|
|
default:
|
|
/*
|
|
* A fine point: _exit(0), not exit(0), to avoid triggering
|
|
* atexit(3) processing
|
|
*/
|
|
_exit(0);
|
|
}
|
|
|
|
newgrp = setsid();
|
|
oerrno = errno;
|
|
if (osa_ok != -1)
|
|
__libc_sigaction(SIGHUP, &osa, NULL);
|
|
|
|
if (newgrp == -1) {
|
|
errno = oerrno;
|
|
return (-1);
|
|
}
|
|
|
|
if (chdirfd != -1)
|
|
(void)fchdir(chdirfd);
|
|
|
|
if (nullfd != -1) {
|
|
(void)_dup2(nullfd, STDIN_FILENO);
|
|
(void)_dup2(nullfd, STDOUT_FILENO);
|
|
(void)_dup2(nullfd, STDERR_FILENO);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
daemon(int nochdir, int noclose)
|
|
{
|
|
int chdirfd, nullfd, ret;
|
|
|
|
if (!noclose)
|
|
nullfd = _open(_PATH_DEVNULL, O_RDWR, 0);
|
|
else
|
|
nullfd = -1;
|
|
|
|
if (!nochdir)
|
|
chdirfd = _open("/", O_EXEC);
|
|
else
|
|
chdirfd = -1;
|
|
|
|
ret = daemonfd(chdirfd, nullfd);
|
|
|
|
if (chdirfd != -1)
|
|
_close(chdirfd);
|
|
|
|
if (nullfd > 2)
|
|
_close(nullfd);
|
|
|
|
return (ret);
|
|
}
|