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daemon.c
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daemon.c
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/*
* libslack - https://libslack.org
*
* Copyright (C) 1999-2004, 2010, 2020-2023 raf <raf@raf.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses/>.
*
* 20230824 raf <raf@raf.org>
*/
/*
=head1 NAME
I<libslack(daemon)> - daemon module
=head1 SYNOPSIS
#include <slack/std.h>
#include <slack/daemon.h>
typedef void daemon_config_parser_t(void *obj, const char *path, char *line, size_t lineno);
int daemon_started_by_init(void);
int daemon_started_by_inetd(void);
int daemon_prevent_core(void);
int daemon_revoke_privileges(void);
int daemon_become_user(uid_t uid, gid_t gid, char *user);
char *daemon_absolute_path(const char *path);
int daemon_path_is_safe(const char *path, char *explanation, size_t explanation_size);
void *daemon_parse_config(const char *path, void *obj, daemon_config_parser_t *parser);
int daemon_pidfile(const char *name);
int daemon_init(const char *name);
int daemon_close(void);
pid_t daemon_getpid(const char *name);
int daemon_is_running(const char *name);
int daemon_stop(const char *name);
=head1 DESCRIPTION
This module provides functions for writing daemons. There are many tasks
that need to be performed to correctly set up a daemon process. This can be
tedious. These functions perform these tasks for you.
=over 4
=cut
*/
#include "config.h"
#ifndef NO_POSIX_SOURCE
#define NO_POSIX_SOURCE /* For ELOOP on FreeBSD-8.0 */
#endif
#ifndef _BSD_SOURCE
#define _BSD_SOURCE /* For setgroups(2) and S_ISLNK(2) on Linux */
#endif
#ifndef _DEFAULT_SOURCE
#define _DEFAULT_SOURCE /* New name for _BSD_SOURCE */
#endif
#ifndef __BSD_VISIBLE
#define __BSD_VISIBLE 1 /* For setgroups(2) and initgroups(2) on FreeBSD-8.0 */
#endif
#ifndef _NETBSD_SOURCE
#define _NETBSD_SOURCE /* For endpwent, endgrent, setgroups, initgroups, lstat, readlink on NetBSD-5.0.2 */
#endif
#include "std.h"
#include <fcntl.h>
#include <pwd.h>
#include <grp.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/resource.h>
#include "daemon.h"
#include "mem.h"
#include "err.h"
#include "lim.h"
#include "fio.h"
#ifndef HAVE_SNPRINTF
#include "snprintf.h"
#endif
#ifndef TEST
static struct
{
pthread_mutex_t lock; /* Mutex lock for structure */
char *pidfile; /* Name of the locked pid file */
int pid_fd; /* Open file descriptor of the pid file */
dev_t pid_dev; /* Device that the pid file is on */
ino_t pid_inode; /* Inode of the pid file */
}
g =
{
PTHREAD_MUTEX_INITIALIZER, /* lock */
NULL, /* pidfile */
-1, /* pid_fd */
(dev_t)0, /* pid_dev */
(ino_t)0 /* pid_inode */
};
#define ptry(action) { int err = (action); if (err) return set_errno(err); }
/*
=item C<int daemon_started_by_init(void)>
If this process was started by I<init(8)> (i.e. if the parent process id is
1), returns 1. If not, returns C<0>. If it was, we might be getting
respawned so I<fork(2)> and I<exit(2)> would be a big mistake (and
unnecessary anyway, since there is no controlling terminal). On error,
returns C<-1> with C<errno> set appropriately.
=cut
*/
int daemon_started_by_init(void)
{
return (getppid() == 1);
}
/*
=item C<int daemon_started_by_inetd(void)>
If this process was started by I<inetd(8)> (i.e. if I<stdin> is a socket),
returns C<1>. If not, returns C<0>. On error, returns C<-1> with C<errno>
set appropriately. If it was, C<stdin>, C<stdout> and C<stderr> would be
opened to a socket. Closing them would be a big mistake. We also would not
need to I<fork(2)> and I<exit(2)> because there is no controlling terminal.
=cut
*/
int daemon_started_by_inetd(void)
{
size_t optlen = sizeof(int);
int optval;
return (getsockopt(STDIN_FILENO, SOL_SOCKET, SO_TYPE, &optval, (void *)&optlen) == 0);
}
/*
=item C<int daemon_prevent_core(void)>
Prevents core files from being generated. This is used to prevent leaking
sensitive information in daemons run by I<root>. On success, returns C<0>.
On error, returns C<-1> with C<errno> set appropriately.
=cut
*/
int daemon_prevent_core(void)
{
struct rlimit limit[1] = {{ 0, 0 }};
if (getrlimit(RLIMIT_CORE, limit) == -1)
return -1;
limit->rlim_cur = 0;
return setrlimit(RLIMIT_CORE, limit);
}
/*
=item C<int daemon_revoke_privileges(void)>
Revokes setuid and setgid privileges. Useful when your program does not
require any special privileges, and may become unsafe if incorrectly
installed with special privileges. Also useful when your program only
requires special privileges initially upon startup (e.g. binding to a
privileged socket). Performs the following tasks: Sets the effective gid to
the real gid if they differ. Checks that they no longer differ. Sets the
effective uid to the real uid if they differ. Checks that they no longer
differ. Also closes /etc/passwd and /etc/group in case they were opened by
I<root> and give access to user and group passwords. On success, returns
C<0>. On error, returns C<-1> with C<errno> set appropriately.
=cut
*/
int daemon_revoke_privileges(void)
{
uid_t uid = getuid();
gid_t gid = getgid();
uid_t euid = geteuid();
gid_t egid = getegid();
if (egid != gid && (setgid(gid) == -1 || getegid() != getgid()))
return -1;
if (euid != uid && (setuid(uid) == -1 || geteuid() != getuid()))
return -1;
endpwent();
endgrent();
return 0;
}
/*
=item C<int daemon_become_user(uid_t uid, gid_t gid, char *user)>
Changes the owner and group of the process to C<uid> and C<gid>,
respectively. If C<user> is not null, the supplementary group list will be
initialised with I<initgroups(3)>. Otherwise, the supplementary group list
will be cleared of all groups. On success, returns C<0>. On error, returns
C<-1> with C<errno> set appropriately. Only I<root> can use this function.
=cut
*/
int daemon_become_user(uid_t uid, gid_t gid, char *user)
{
gid_t gids[10];
int g = 0;
if (setgroups(0, NULL) == -1 || (g = getgroups(0, NULL)) != 0)
{
/* FreeBSD always returns the primary group */
if (g != 1 || getgroups(10, gids) != 1 || gids[0] != getgid())
return -1;
}
if (setgid(gid) == -1 || getgid() != gid || getegid() != gid)
return -1;
if (user && initgroups(user, gid) == -1)
return -1;
if (setuid(uid) == -1 || getuid() != uid || geteuid() != uid)
return -1;
return 0;
}
/*
=item C<char *daemon_absolute_path(const char *path)>
Returns C<path> converted into an absolute path. Cleans up any C<.> and
C<..> and C<//> and trailing C</> found in the returned path. Note that the
returned path looks canonical but isn't, because symbolic links are not
followed and expanded. It is the caller's responsibility to deallocate the
path returned with I<free(3)> or I<mem_release(3)> or I<mem_destroy(3)>. It
is strongly recommended to use I<mem_destroy(3)>, because it also sets the
pointer variable to C<null>. On success, returns the absolute path. On
error, returns C<null> with C<errno> set appropriately.
=cut
*/
char *daemon_absolute_path(const char *path)
{
size_t path_len;
char *abs_path;
char *p;
if (!path)
return set_errnull(EINVAL);
/* Make path absolute and mostly canonical (don't follow symbolic links) */
if (*path != PATH_SEP)
{
long lim = limit_path();
char *cwd = mem_create(lim, char);
size_t cwd_len;
int rc;
if (!cwd)
return NULL;
if (!getcwd(cwd, lim))
{
mem_release(cwd);
return NULL;
}
cwd_len = strlen(cwd);
if (cwd_len + 1 + strlen(path) >= lim)
{
mem_release(cwd);
return set_errnull(ENAMETOOLONG);
}
rc = snprintf(cwd + cwd_len, lim - cwd_len, "%c%s", PATH_SEP, path);
if (rc == -1 || rc >= lim - cwd_len)
{
mem_release(cwd);
return set_errnull(ENAMETOOLONG);
}
abs_path = cwd;
}
else
{
if (!(abs_path = mem_strdup(path)))
return NULL;
}
/* Clean up any // and . and .. in the absolute path */
path_len = strlen(abs_path);
for (p = abs_path; *p; ++p)
{
if (p[0] == PATH_SEP)
{
if (p[1] == PATH_SEP)
{
memmove(p, p + 1, path_len + 1 - (p + 1 - abs_path));
--path_len;
--p;
}
else if (p[1] == '.')
{
if (p[2] == PATH_SEP || p[2] == nul)
{
int keep_sep = (p == abs_path && p[2] == nul);
memmove(p + keep_sep, p + 2, path_len + 1 - (p + 2 - abs_path));
path_len -= 2 - keep_sep;
--p;
}
else if (p[2] == '.' && (p[3] == PATH_SEP || p[3] == nul))
{
char *scan, *parent;
int keep_sep;
for (scan = parent = p; scan > abs_path; )
{
if (*--scan == PATH_SEP)
{
parent = scan;
break;
}
}
keep_sep = (parent == abs_path && p[3] == nul);
memmove(parent + keep_sep, p + 3, path_len + 1 - (p + 3 - abs_path));
path_len -= p + 3 - parent;
p = parent - 1;
}
}
}
}
/* Strip off any trailing / */
while (path_len > 1 && abs_path[path_len - 1] == PATH_SEP)
abs_path[--path_len] = nul;
return abs_path;
}
/*
=item C<int daemon_path_is_safe(const char *path, char *explanation, size_t explanation_size)>
Checks that the file referred to by C<path> is not group- or world-writable.
Also checks that the containing directories are not group- or
world-writable, following symbolic links. Useful when you need to know
whether or not you can trust a user supplied configuration/command file
before reading and acting upon its contents. On success, returns C<1> if
C<path> is safe or C<0> if it is not. When the path is not safe, an
explanation is written to the C<explanation> buffer (if it is not C<null>).
No more than C<explanation_size> bytes including the terminating C<nul> byte
will be written to the C<explanation> buffer. On error, returns C<-1> with
C<errno> set appropriately.
=cut
*/
static int daemon_check_path(char *path, char *explanation, size_t explanation_size, int level)
{
struct stat status[1];
char *sep;
int rc;
if (level > 16)
return set_errno(ELOOP);
for (sep = path + strlen(path); sep; sep = strrchr(path, PATH_SEP))
{
sep[sep == path] = nul;
if (lstat(path, status) == -1)
return -1;
if (S_ISLNK(status->st_mode))
{
size_t lim;
char *sym_linked;
char *tmp;
lim = limit_path();
if (!(sym_linked = mem_create(lim, char)))
return -1;
memset(sym_linked, 0, lim);
if (readlink(path, sym_linked, lim) == -1)
{
mem_release(sym_linked);
return -1;
}
if (*sym_linked != PATH_SEP)
{
if (!(tmp = mem_create(lim, char)))
{
mem_release(sym_linked);
return -1;
}
rc = snprintf(tmp, lim, "%s%c..%c%s", path, PATH_SEP, PATH_SEP, sym_linked);
if (rc == -1 || rc >= lim)
{
mem_release(sym_linked);
mem_release(tmp);
return set_errno(ENAMETOOLONG);
}
rc = snprintf(sym_linked, lim, "%s", tmp);
mem_release(tmp);
if (rc == -1 || rc >= lim)
{
mem_release(sym_linked);
return set_errno(ENAMETOOLONG);
}
}
tmp = daemon_absolute_path(sym_linked);
mem_release(sym_linked);
if (!(sym_linked = tmp))
return -1;
rc = daemon_check_path(sym_linked, explanation, explanation_size, level + 1);
mem_release(sym_linked);
switch (rc)
{
case -1: return -1;
case 0: return 0;
case 1: break;
}
}
else if (status->st_mode & (S_IWGRP | S_IWOTH))
{
if (explanation)
{
snprintf(explanation, explanation_size, "%s is %s%s%swritable", path,
(status->st_mode & S_IWGRP) ? "group-" : "",
((status->st_mode & (S_IWGRP | S_IWOTH)) == (S_IWGRP | S_IWOTH)) ? " and " : "",
(status->st_mode & S_IWOTH) ? "world-" : ""
);
}
return 0;
}
if (sep == path)
break;
}
return 1;
}
int daemon_path_is_safe(const char *path, char *explanation, size_t explanation_size)
{
char *abs_path;
int rc;
if (!path)
return set_errno(EINVAL);
abs_path = daemon_absolute_path(path);
if (!abs_path)
return -1;
rc = daemon_check_path(abs_path, explanation, explanation_size, 0);
mem_release(abs_path);
return rc;
}
/*
=item C<void *daemon_parse_config(const char *path, void *obj, daemon_config_parser_t *parser)>
Parses the text configuration file named C<path>. Blank lines are ignored.
Comments (C<'#'> to end of line) are ignored. Lines that end with C<'\'> are
joined with the following line. There may be whitespace characters, and even
a comment, after the C<'\'> character, but nothing else. The C<parser>
function is called with the client supplied C<obj>, the file name, the line
and the line number as arguments. On success, returns C<obj>. On error,
returns C<null> (i.e. if the configuration file could not be read). Note:
Don't parse config files unless they are "safe" as determined by
I<daemon_path_is_safe(3)>.
=cut
*/
void *daemon_parse_config(const char *path, void *obj, daemon_config_parser_t *parser)
{
FILE *conf;
char line[BUFSIZ];
char buf[BUFSIZ];
int lineno;
int rc;
if (!(conf = fopen(path, "r")))
return NULL;
line[0] = nul;
for (lineno = 1; fgets(buf, BUFSIZ, conf); ++lineno)
{
char *start = buf;
char *end;
size_t length;
int cont_line;
/* Strip trailing comments */
if ((end = strchr(start, '#')))
*end = nul;
else
end = start + strlen(start);
/* Skip trailing spaces (allows comments after line continuation) */
while (end > start && isspace((int)(unsigned char)end[-1]))
--end;
/* Skip empty lines */
if (*start == nul || start == end)
continue;
/* Perform line continuation */
if ((cont_line = (end[-1] == '\\')))
--end;
length = strlen(line);
rc = snprintf(line + length, BUFSIZ - length, "%*.*s", (int)(end - start), (int)(end - start), start);
if (rc == -1 || rc >= BUFSIZ - length)
return NULL;
if (cont_line)
continue;
/* Parse the resulting line */
parser(obj, path, line, lineno);
line[0] = nul;
}
fclose(conf);
return obj;
}
/*
C<int daemon_construct_pidfile(const char *name, char **pidfile)>
Constructs the pidfile for the given C<name> in C<pidfile>. If C<name> is
already an absolute path, it is just copied into the new buffer directly. On
success, returns C<0>, and the resulting buffer in C<pidfile> must be
deallocated by the caller. On error, returns C<-1> with C<errno> set
appropriately.
*/
static int daemon_construct_pidfile(const char *name, char **pidfile)
{
long path_len;
const char *pid_dir;
char *suffix = ".pid";
size_t size;
/* Construct the pidfile */
path_len = limit_path();
pid_dir = (getuid()) ? USER_PID_DIR : ROOT_PID_DIR;
size = ((*name == PATH_SEP) ? strlen(name) : sizeof(pid_dir) + 1 + strlen(name) + strlen(suffix)) + 1;
if (size > path_len)
return set_errno(ENAMETOOLONG);
if (!*pidfile && !(*pidfile = mem_create(path_len, char)))
return -1;
if (*name == PATH_SEP)
snprintf(*pidfile, path_len, "%s", name);
else
snprintf(*pidfile, path_len, "%s%c%s%s", pid_dir, PATH_SEP, name, suffix);
return 0;
}
/*
C<int daemon_lock_pidfile(const char *pidfile)>
Open and lock the file referred to by C<pidfile>. On success, returns the
file descriptor of the opened and locked file. On error, returns C<-1> with
C<errno> set appropriately.
*/
static int daemon_lock_pidfile(char *pidfile)
{
mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
struct stat statbuf_fd[1], statbuf_fs[1];
int pid_fd;
start:
/* This is broken over NFS (Linux). So pidfiles must reside locally. */
if ((pid_fd = open(pidfile, O_RDWR | O_CREAT | O_EXCL, mode)) == -1)
{
if (errno != EEXIST)
return -1;
/*
** The pidfile already exists. Is it locked?
** If so, another invocation is still alive.
** If not, the invocation that created it has died.
** Open the pidfile to attempt a lock.
*/
if ((pid_fd = open(pidfile, O_RDWR)) == -1)
{
/*
** We couldn't open the file. That means that it existed
** a moment ago but has been since been deleted. Maybe if
** we try again now, it'll work (unless another process is
** about to re-create it before we do, that is).
*/
if (errno == ENOENT)
goto start;
return -1;
}
}
if (fcntl_lock(pid_fd, F_SETLK, F_WRLCK, SEEK_SET, 0, 0) == -1)
{
close(pid_fd);
return -1;
}
/*
** The pidfile may have been unlinked, after we opened it, by another daemon
** process that was dying between the last open() and the fcntl(). But that
** shouldn't happen any more. There's no use hanging on to a locked file that
** doesn't exist (and there's nothing to stop another daemon process from
** creating and locking a new instance of the file. So, if the pidfile has
** been deleted, we abandon this lock and start again. Note that it may have
** been deleted and subsequently re-created by yet another daemon process just
** starting up, so check that that hasn't happened as well by comparing inode
** numbers. If it has, we also abandon this lock and start again.
*/
if (fstat(pid_fd, statbuf_fd) == -1)
{
/* This shouldn't happen */
close(pid_fd);
return -1;
}
if (stat(pidfile, statbuf_fs) == -1)
{
/* The pidfile has been unlinked so we start again */
if (errno == ENOENT)
{
close(pid_fd);
goto start;
}
close(pid_fd);
return -1;
}
else if (statbuf_fd->st_ino != statbuf_fs->st_ino)
{
/* The pidfile has been unlinked and re-created so we start again */
close(pid_fd);
goto start;
}
/* Prevent leaking this file descriptor into child processes. */
fcntl_set_fdflag(pid_fd, FD_CLOEXEC);
/* Record its dev and inode so we know not to delete the wrong pidfile later */
g.pid_dev = statbuf_fd->st_dev;
g.pid_inode = statbuf_fd->st_ino;
return pid_fd;
}
/*
C<int daemon_pidfile_unlocked(const char *name)>
Equivalent to I<daemon_pidfile(3)> except that the daemon module's mutex is
not locked and unlocked.
*/
static int daemon_pidfile_unlocked(const char *name)
{
char pid[32];
/* Check argument */
if (!name)
return set_errno(EINVAL);
/* Build the pidfile path */
if (daemon_construct_pidfile(name, &g.pidfile) == -1)
return -1;
/* Open it and lock it (if possible) */
if ((g.pid_fd = daemon_lock_pidfile(g.pidfile)) == -1)
{
mem_destroy(&g.pidfile);
return -1;
}
/* Store our pid */
snprintf(pid, 32, "%d\n", (int)getpid());
if (write(g.pid_fd, pid, strlen(pid)) != strlen(pid))
{
daemon_close();
return -1;
}
/*
** Flaw: If someone unceremoniously unlinks the pidfile,
** we won't know about it and nothing will stop another
** invocation from starting up. However, if that does happen,
** and another invocation does start, and then this invocation
** terminates, it won't delete the other instance's pidfile.
*/
return 0;
}
/*
=item C<int daemon_pidfile(const char *name)>
Creates a pid file for a daemon and locks it. The file has one line
containing the process id of the daemon. The well-known locations for the
file is defined in C<ROOT_PID_DIR> for I<root> (C<"/var/run"> by default)
and C<USER_PID_DIR> for all other users (C<"/tmp"> by default). The name of
the file is the name of the daemon (given by the I<name> argument) followed
by C<".pid"> (If I<name> is an absolute file path, it is used as is). The
presence of this file will prevent two daemons with the same name from
running at the same time. On success, returns C<0>. On error, returns C<-1>
with C<errno> set appropriately. B<Note:> This is called by
I<daemon_init(3)>, so there is usually no need to call this function
directly.
=cut
*/
int daemon_pidfile(const char *name)
{
int rc;
ptry(pthread_mutex_lock(&g.lock))
rc = daemon_pidfile_unlocked(name);
ptry(pthread_mutex_unlock(&g.lock))
return rc;
}
/*
=item C<int daemon_init(const char *name)>
Initialises a daemon by performing the following tasks:
=over 4
=item *
If the process was not invoked by I<init(8)> (i.e. parent process id is 1)
or I<inetd(8)> (i.e. C<stdin> is a socket):
=over 4
=item *
Ignore C<SIGHUP> signals in case the current process session leader
terminates while attached to a controlling terminal causing us to
receive a C<SIGHUP> signal before we start our own process session below.
This can happen when the process that calls I<daemon_init(3)> was itself
invoked interactively via the shell builtin C<exec>. When this initial
process terminates below, the terminal emulator that invoked the shell also
terminates.
=item *
Background the process to lose process group leadership.
=item *
Start a new process session.
=item *
Background the process again to lose process session leadership. Under
I<SVR4>, this prevents the process from ever gaining a controlling terminal.
This is only necessary under I<SVR4>, but is always done for simplicity.
Note that ignoring C<SIGHUP> signals earlier means that when the newly
created process session leader terminates, then even if it has a controlling
terminal open, the newly backgrounded process won't receive the
corresponding C<SIGHUP> signal that is sent to all processes in the process
session's foreground process group, because it inherited signal dispositions
from the initial process.
=back
=item *
Change the current directory to the root directory so as not to hamper
umounts.
=item *
Clear the umask to enable explicit file creation modes.
=item *
Close all open file descriptors. If the process was invoked by I<inetd(8)>,
C<stdin>, C<stdout> and C<stderr> are left open, because they are open to a
socket.
=item *
Open C<stdin>, C<stdout> and C<stderr> to C</dev/null> in case something
requires them to be open. Of course, this is not done if the process was
invoked by I<inetd(8)>.
=item *
If C<name> is non-null, create and lock a file containing the process id of
the process. The presence of this locked file prevents two instances of a
daemon with the same name from running at the same time. The default
location of the pidfile is C</var/run> for I<root> (C</etc> on I<Solaris>,
C</opt/local/var/run> on I<macOS> when installed via I<macports>), and
C</tmp> for ordinary users.
=back
On success, returns C<0>. On error, returns C<-1> with C<errno> set
appropriately.
=cut
*/
int daemon_init(const char *name)
{
pid_t pid;
long nopen;
int fd;
/*
** Don't setup a daemon-friendly process context
** if started by init(8) or inetd(8).
*/
if (!(daemon_started_by_init() || daemon_started_by_inetd()))
{
/*
** Ignore SIGHUP signals in case the current process session leader
** terminates while attached to a controlling terminal causing us to
** receive a SIGHUP signal before we start our own process session below.
*/
struct sigaction act[1];
act->sa_handler = SIG_IGN;
sigemptyset(&act->sa_mask);
act->sa_flags = 0;
if (sigaction(SIGHUP, act, NULL) == -1)
return -1;
/*
** Background the process.
** Lose process session/group leadership.
*/
if ((pid = fork()) == -1)
return -1;
if (pid)
{
#ifndef DISABLE_DAEMON_INIT_EXIT_DELAY_MSEC
/*
** If the user has requested an exit delay because they use
** "exec daemon" to run KDE applications that are failing
** immediately, then delay the parent's exit by the given
** number of milliseconds.
**
** Note: We are not delaying the start of the client, just the
** exit of the initial parent process.
**
** Note Also: I have no idea why this delay seems to fix
** "exec daemon kde-app" failures.
**
** Also Note: This has nothing to do with daemon. The same
** failures occur with "exec kde-app".
**
** Also note: Setting DAEMON_INIT_EXIT_DELAY_MSEC to at least 400
** (i.e. 0.4 seconds) seems to be enough. Your mileage may vary.
*/
char *delay_var;
long delay_msec;
if ((delay_var = getenv("DAEMON_INIT_EXIT_DELAY_MSEC")) && (delay_msec = atol(delay_var)) > 0)
nap(delay_msec / 1000, (delay_msec & 1000) * 1000);
#endif
exit(EXIT_SUCCESS);
}
/* Become a process session leader. */
/* This can only fail when we're already a session leader. */
setsid();
/*
** Lose process session leadership to prevent gaining a controlling
** terminal in SVR4. Always do it in case we don't know what flavour
** of UNIX this system is.
*/
if ((pid = fork()) == -1)
return -1;
if (pid)
exit(EXIT_SUCCESS);
}
/* Enter the root directory to prevent hampering umounts. */
if (chdir(ROOT_DIR) == -1)
return -1;