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/*
* Copyright (C) 2003-2009 The Music Player Daemon Project
* http://www.musicpd.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, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "daemon.h"
#include <glib.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#ifndef WIN32
#include <signal.h>
#include <pwd.h>
#include <grp.h>
#endif
#undef G_LOG_DOMAIN
#define G_LOG_DOMAIN "daemon"
#ifndef WIN32
/** the Unix user name which MPD runs as */
static char *user_name;
/** the Unix user id which MPD runs as */
static uid_t user_uid = (uid_t)-1;
/** the Unix group id which MPD runs as */
static gid_t user_gid = (pid_t)-1;
/** the absolute path of the pidfile */
static char *pidfile;
/* whether "group" conf. option was given */
static bool had_group = false;
void
daemonize_kill(void)
{
FILE *fp;
int pid, ret;
if (pidfile == NULL)
g_error("no pid_file specified in the config file");
fp = fopen(pidfile, "r");
if (fp == NULL)
g_error("unable to open pid file \"%s\": %s",
pidfile, g_strerror(errno));
if (fscanf(fp, "%i", &pid) != 1) {
g_error("unable to read the pid from file \"%s\"",
pidfile);
}
fclose(fp);
ret = kill(pid, SIGTERM);
if (ret < 0)
g_error("unable to kill proccess %i: %s",
pid, g_strerror(errno));
exit(EXIT_SUCCESS);
}
#endif
void
daemonize_close_stdin(void)
{
int fd = open("/dev/null", O_RDONLY);
if (fd < 0)
close(STDIN_FILENO);
else if (fd != STDIN_FILENO) {
dup2(fd, STDIN_FILENO);
close(fd);
}
}
#ifndef WIN32
void
daemonize_set_user(void)
{
if (user_name == NULL)
return;
/* set gid */
if (user_gid != (gid_t)-1 && user_gid != getgid()) {
if (setgid(user_gid) == -1) {
g_error("cannot setgid to %d: %s",
(int)user_gid, g_strerror(errno));
}
}
#ifdef _BSD_SOURCE
/* init suplementary groups
* (must be done before we change our uid)
*/
if (!had_group && initgroups(user_name, user_gid) == -1) {
g_warning("cannot init supplementary groups "
"of user \"%s\": %s",
user_name, g_strerror(errno));
}
#endif
/* set uid */
if (user_uid != (uid_t)-1 && user_uid != getuid() &&
setuid(user_uid) == -1) {
g_error("cannot change to uid of user \"%s\": %s",
user_name, g_strerror(errno));
}
}
static void
daemonize_detach(void)
{
pid_t pid;
/* flush all file handles before duplicating the buffers */
fflush(NULL);
/* detach from parent process */
pid = fork();
if (pid < 0)
g_error("fork() failed: %s", g_strerror(errno));
if (pid > 0)
/* exit the parent process */
_exit(EXIT_SUCCESS);
/* release the current working directory */
if (chdir("/") < 0)
g_error("problems changing to root directory");
/* detach from the current session */
setsid();
g_debug("daemonized!");
}
void
daemonize(bool detach)
{
FILE *fp = NULL;
if (pidfile != NULL) {
/* do this before daemon'izing so we can fail gracefully if we can't
* write to the pid file */
g_debug("opening pid file");
fp = fopen(pidfile, "w+");
if (!fp) {
g_error("could not create pid file \"%s\": %s",
pidfile, g_strerror(errno));
}
}
if (detach)
daemonize_detach();
if (pidfile != NULL) {
g_debug("writing pid file");
fprintf(fp, "%lu\n", (unsigned long)getpid());
fclose(fp);
}
}
void
daemonize_init(const char *user, const char *group, const char *_pidfile)
{
if (user) {
struct passwd *pwd = getpwnam(user);
if (!pwd)
g_error("no such user \"%s\"", user);
user_uid = pwd->pw_uid;
user_gid = pwd->pw_gid;
user_name = g_strdup(user);
/* this is needed by libs such as arts */
g_setenv("HOME", pwd->pw_dir, true);
}
if (group) {
struct group *grp = grp = getgrnam(group);
if (!grp)
g_error("no such group \"%s\"", group);
user_gid = grp->gr_gid;
had_group = true;
}
pidfile = g_strdup(_pidfile);
}
void
daemonize_finish(void)
{
if (pidfile != NULL)
unlink(pidfile);
g_free(user_name);
g_free(pidfile);
}
#endif
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