/*
* daemon.c : Handle daemon initialization
* Copyright (C) 1996 Thomas Koenig
*
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_STDARG_H
#include <stdarg.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>
#include <fcntl.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYSLOG_H
#include <syslog.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include "daemon.h"
#include "privs.h"
int daemon_debug = 0;
int daemon_foreground = 0;
static int
lock_fd(int fd)
{
struct flock lock;
lock.l_type = F_WRLCK;
lock.l_whence = SEEK_SET;
lock.l_start = 0;
lock.l_len = 0;
return fcntl(fd, F_SETLK, &lock);
}
void
perr(const char *fmt,...)
{
char buf[1024];
va_list args;
va_start(args, fmt);
vsnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
if (daemon_debug) {
perror(buf);
} else
syslog(LOG_ERR, "%s: %m", buf);
exit(EXIT_FAILURE);
}
void
lerr(const char *fmt,...)
{
char buf[1024];
va_list args;
va_start(args, fmt);
vsnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
if (daemon_debug) {
perror(buf);
} else
syslog(LOG_ERR, "%s: %m", buf);
}
void
pabort(const char *fmt,...)
{
char buf[1024];
va_list args;
va_start(args, fmt);
vsnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
if (daemon_debug) {
fprintf(stderr, "%s\n", buf);
} else
syslog(LOG_ERR, "%s", buf);
exit(EXIT_FAILURE);
}
void
daemon_setup()
{
/* Set up standard daemon environment */
pid_t pid;
mode_t old_umask;
int fd;
FILE *fp;
if (!daemon_debug) {
close(0);
close(1);
close(2);
if ((open("/dev/null", O_RDWR) != 0) ||
(open("/dev/null", O_RDWR) != 1) ||
(open("/dev/null", O_RDWR) != 2)) {
perr("Error redirecting I/O");
}
}
if (daemon_foreground)
pid = getpid();
else {
pid = fork();
if (pid == -1) {
perr("Cannot fork");
} else if (pid != 0) {
exit(0);
}
(void) setsid();
}
old_umask = umask(S_IWGRP | S_IWOTH);
PRIV_START
fd = open(PIDFILE, O_RDWR | O_CREAT | O_EXCL, S_IWUSR | S_IRUSR | S_IRGRP | S_IROTH);
if (fd == -1) {
if (errno != EEXIST)
perr("Cannot open " PIDFILE);
if ((fd = open(PIDFILE, O_RDWR)) < 0)
perr("Cannot open " PIDFILE);
fp = fdopen(fd, "rw");
if (fp == NULL) {
perr("Cannot open " PIDFILE " for reading");
}
pid = -1;
if ((fscanf(fp, "%d", &pid) != 1) || (pid == getpid())
|| (lock_fd(fileno(fp)) == 0)) {
int rc;
syslog(LOG_NOTICE, "Removing stale lockfile for pid %d", pid);
rc = unlink(PIDFILE);
if (rc == -1) {
perr("Cannot unlink " PIDFILE);
}
} else {
pabort("Another atd already running with pid %d", pid);
}
fclose(fp);
unlink(PIDFILE);
fd = open(PIDFILE, O_RDWR | O_CREAT | O_EXCL,
S_IWUSR | S_IRUSR | S_IRGRP | S_IROTH);
if (fd == -1)
perr("Cannot open " PIDFILE " the second time round");
}
if (lock_fd(fd) == -1)
perr("Cannot lock " PIDFILE);
fp = fdopen(fd, "w");
if (fp == NULL)
perr("Special weirdness: fdopen failed");
fprintf(fp, "%d\n", getpid());
/* We do NOT close fd, since we want to keep the lock. However, we don't
* want to keep the file descriptor in case of an exec().
*/
fflush(fp);
fcntl(fd, F_SETFD, (long) 1);
PRIV_END
return;
}
void
daemon_cleanup()
{
PRIV_START
unlink(PIDFILE);
PRIV_END
}