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/*
* Copyright (C) 2003-2014 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 "config.h"
#include "Daemon.hxx"
#include "system/FatalError.hxx"
#include "fs/AllocatedPath.hxx"
#include "fs/FileSystem.hxx"
#include "util/Domain.hxx"
#include "PidFile.hxx"
#include "Log.hxx"
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#ifndef WIN32
#include <signal.h>
#include <pwd.h>
#include <grp.h>
#endif
static constexpr Domain daemon_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 = (gid_t)-1;
/** the absolute path of the pidfile */
static AllocatedPath pidfile = AllocatedPath::Null();
/* whether "group" conf. option was given */
static bool had_group = false;
void
daemonize_kill(void)
{
FILE *fp;
int pid, ret;
if (pidfile.IsNull())
FatalError("no pid_file specified in the config file");
fp = FOpen(pidfile, "r");
if (fp == nullptr) {
const std::string utf8 = pidfile.ToUTF8();
FormatFatalSystemError("Unable to open pid file \"%s\"",
utf8.c_str());
}
if (fscanf(fp, "%i", &pid) != 1) {
const std::string utf8 = pidfile.ToUTF8();
FormatFatalError("unable to read the pid from file \"%s\"",
utf8.c_str());
}
fclose(fp);
ret = kill(pid, SIGTERM);
if (ret < 0)
FormatFatalSystemError("unable to kill process %i",
int(pid));
exit(EXIT_SUCCESS);
}
void
daemonize_close_stdin(void)
{
close(STDIN_FILENO);
open("/dev/null", O_RDONLY);
}
void
daemonize_set_user(void)
{
if (user_name == nullptr)
return;
/* set gid */
if (user_gid != (gid_t)-1 && user_gid != getgid() &&
setgid(user_gid) == -1) {
FormatFatalSystemError("Failed to set group %d",
(int)user_gid);
}
#ifdef _BSD_SOURCE
/* init supplementary groups
* (must be done before we change our uid)
*/
if (!had_group &&
/* no need to set the new user's supplementary groups if
we are already this user */
user_uid != getuid() &&
initgroups(user_name, user_gid) == -1) {
FormatFatalSystemError("Failed to set supplementary groups "
"of user \"%s\"",
user_name);
}
#endif
/* set uid */
if (user_uid != (uid_t)-1 && user_uid != getuid() &&
setuid(user_uid) == -1) {
FormatFatalSystemError("Failed to set user \"%s\"",
user_name);
}
}
static void
daemonize_detach(void)
{
/* flush all file handles before duplicating the buffers */
fflush(nullptr);
/* detach from parent process */
switch (fork()) {
case -1:
FatalSystemError("fork() failed");
case 0:
break;
default:
/* exit the parent process */
_exit(EXIT_SUCCESS);
}
/* release the current working directory */
if (chdir("/") < 0)
FatalError("problems changing to root directory");
/* detach from the current session */
setsid();
LogDebug(daemon_domain, "daemonized");
}
void
daemonize(bool detach)
{
/* do this before daemon'izing so we can fail gracefully if we
can't write to the pid file */
PidFile pidfile2(pidfile);
if (detach)
daemonize_detach();
pidfile2.Write();
}
void
daemonize_init(const char *user, const char *group, AllocatedPath &&_pidfile)
{
if (user) {
struct passwd *pwd = getpwnam(user);
if (pwd == nullptr)
FormatFatalError("no such user \"%s\"", user);
user_uid = pwd->pw_uid;
user_gid = pwd->pw_gid;
user_name = strdup(user);
/* this is needed by libs such as arts */
setenv("HOME", pwd->pw_dir, true);
}
if (group) {
struct group *grp = getgrnam(group);
if (grp == nullptr)
FormatFatalError("no such group \"%s\"", group);
user_gid = grp->gr_gid;
had_group = true;
}
pidfile = std::move(_pidfile);
}
void
daemonize_finish(void)
{
if (!pidfile.IsNull()) {
RemoveFile(pidfile);
pidfile = AllocatedPath::Null();
}
free(user_name);
}
#endif
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