You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
292 lines
6.4 KiB
292 lines
6.4 KiB
3 months ago
|
/*
|
||
|
|
* UCW Library -- Daemonization
|
||
|
|
*
|
||
|
|
* (c) 2012--2014 Martin Mares <mj@ucw.cz>
|
||
|
|
* (c) 2014 Pavel Charvat <pchar@ucw.cz>
|
||
|
|
*
|
||
|
|
* This software may be freely distributed and used according to the terms
|
||
|
|
* of the GNU Lesser General Public License.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <ucw/lib.h>
|
||
|
|
#include <ucw/daemon.h>
|
||
|
|
#include <ucw/strtonum.h>
|
||
|
|
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <fcntl.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
#include <pwd.h>
|
||
|
|
#include <grp.h>
|
||
|
|
#include <errno.h>
|
||
|
|
#include <string.h>
|
||
|
|
#include <sys/types.h>
|
||
|
|
#include <sys/stat.h>
|
||
|
|
#include <sys/file.h>
|
||
|
|
|
||
|
|
void
|
||
|
|
daemon_resolve_ugid(struct daemon_params *dp)
|
||
|
|
{
|
||
|
|
// Resolve user name
|
||
|
|
const char *u = dp->run_as_user;
|
||
|
|
struct passwd *pw = NULL;
|
||
|
|
if (u)
|
||
|
|
{
|
||
|
|
if (u[0] == '#')
|
||
|
|
{
|
||
|
|
uint id;
|
||
|
|
const char *err = str_to_uint(&id, u, NULL, 10 | STN_WHOLE);
|
||
|
|
if (err)
|
||
|
|
die("Cannot parse user `%s': %s", u, err);
|
||
|
|
dp->run_as_uid = id;
|
||
|
|
dp->want_setuid = 1;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
pw = getpwnam(u);
|
||
|
|
if (!pw)
|
||
|
|
die("No such user `%s'", u);
|
||
|
|
dp->run_as_uid = pw->pw_uid;
|
||
|
|
dp->want_setuid = 1;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Resolve group name
|
||
|
|
const char *g = dp->run_as_group;
|
||
|
|
struct group *gr;
|
||
|
|
if (g)
|
||
|
|
{
|
||
|
|
if (g[0] == '#')
|
||
|
|
{
|
||
|
|
uint id;
|
||
|
|
const char *err = str_to_uint(&id, g, NULL, 10 | STN_WHOLE);
|
||
|
|
if (err)
|
||
|
|
die("Cannot parse group `%s': %s", g, err);
|
||
|
|
dp->run_as_gid = id;
|
||
|
|
dp->want_setgid = 1;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
gr = getgrnam(g);
|
||
|
|
if (!gr)
|
||
|
|
die("No such group `%s'", g);
|
||
|
|
dp->run_as_gid = gr->gr_gid;
|
||
|
|
dp->want_setgid = 1;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else if (pw)
|
||
|
|
{
|
||
|
|
dp->run_as_gid = pw->pw_gid;
|
||
|
|
dp->want_setgid = 2;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void
|
||
|
|
daemon_switch_ugid(struct daemon_params *dp)
|
||
|
|
{
|
||
|
|
if (dp->want_setgid && setresgid(dp->run_as_gid, dp->run_as_gid, dp->run_as_gid) < 0)
|
||
|
|
die("Cannot set GID to %d: %m", (int) dp->run_as_gid);
|
||
|
|
if (dp->want_setgid > 1 && initgroups(dp->run_as_user, dp->run_as_gid) < 0)
|
||
|
|
die("Cannot initialize groups: %m");
|
||
|
|
if (dp->want_setuid && setresuid(dp->run_as_uid, dp->run_as_uid, dp->run_as_uid) < 0)
|
||
|
|
die("Cannot set UID to %d: %m", (int) dp->run_as_uid);
|
||
|
|
}
|
||
|
|
|
||
|
|
void
|
||
|
|
daemon_init(struct daemon_params *dp)
|
||
|
|
{
|
||
|
|
daemon_resolve_ugid(dp);
|
||
|
|
|
||
|
|
if (dp->flags & DAEMON_FLAG_SIMULATE)
|
||
|
|
return;
|
||
|
|
|
||
|
|
if (dp->pid_file)
|
||
|
|
{
|
||
|
|
// Check that PID file path is absolute
|
||
|
|
if (!(dp->flags & DAEMON_FLAG_PRESERVE_CWD) && dp->pid_file[0] != '/')
|
||
|
|
die("Path to PID file `%s' must be absolute", dp->pid_file);
|
||
|
|
|
||
|
|
// Open PID file
|
||
|
|
dp->pid_fd = open(dp->pid_file, O_RDWR | O_CREAT, 0666);
|
||
|
|
if (dp->pid_fd < 0)
|
||
|
|
die("Cannot open `%s': %m", dp->pid_file);
|
||
|
|
int fl = fcntl(dp->pid_fd, F_GETFD);
|
||
|
|
if (fl < 0 || fcntl(dp->pid_fd, F_SETFD, fl | FD_CLOEXEC))
|
||
|
|
die("Cannot set FD_CLOEXEC: %m");
|
||
|
|
|
||
|
|
// Try to lock it with an exclusive lock
|
||
|
|
if (flock(dp->pid_fd, LOCK_EX | LOCK_NB) < 0)
|
||
|
|
{
|
||
|
|
if (errno == EINTR || errno == EWOULDBLOCK)
|
||
|
|
die("Daemon is already running (`%s' locked)", dp->pid_file);
|
||
|
|
else
|
||
|
|
die("Cannot lock `%s': %m", dp->pid_file);
|
||
|
|
}
|
||
|
|
|
||
|
|
// Make a note that the daemon is starting
|
||
|
|
if (ftruncate(dp->pid_fd, 0) < 0 ||
|
||
|
|
write(dp->pid_fd, "(starting)\n", 11) != 11)
|
||
|
|
die("Error writing `%s': %m", dp->pid_file);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void
|
||
|
|
daemon_run(struct daemon_params *dp, void (*body)(struct daemon_params *dp))
|
||
|
|
{
|
||
|
|
if (dp->flags & DAEMON_FLAG_SIMULATE)
|
||
|
|
{
|
||
|
|
body(dp);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Switch GID and UID
|
||
|
|
daemon_switch_ugid(dp);
|
||
|
|
|
||
|
|
// Create a new session and close stdio
|
||
|
|
setsid();
|
||
|
|
close(0);
|
||
|
|
if (open("/dev/null", O_RDWR, 0) < 0 ||
|
||
|
|
dup2(0, 1) < 0)
|
||
|
|
die("Cannot redirect stdio to `/dev/null': %m");
|
||
|
|
|
||
|
|
// Set umask to a reasonable value
|
||
|
|
umask(022);
|
||
|
|
|
||
|
|
// Do not hold the current working directory
|
||
|
|
if (!(dp->flags & DAEMON_FLAG_PRESERVE_CWD))
|
||
|
|
{
|
||
|
|
if (chdir("/") < 0)
|
||
|
|
die("Cannot chdir to root: %m");
|
||
|
|
}
|
||
|
|
|
||
|
|
// Create pipe to synchronize child process with master and avoid possible
|
||
|
|
// collision between writing of PID and daemon_exit()
|
||
|
|
int pipe_fd[2];
|
||
|
|
if (dp->pid_file && pipe(pipe_fd) < 0)
|
||
|
|
die("Cannot create pipe: %m");
|
||
|
|
|
||
|
|
// Fork
|
||
|
|
pid_t pid = fork();
|
||
|
|
if (pid < 0)
|
||
|
|
die("Cannot fork: %m");
|
||
|
|
if (!pid)
|
||
|
|
{
|
||
|
|
// Wait for master process to finish writing of PID
|
||
|
|
if (dp->pid_file)
|
||
|
|
{
|
||
|
|
byte pipe_buf[1];
|
||
|
|
close(pipe_fd[1]);
|
||
|
|
if (read(pipe_fd[0], pipe_buf, 1) < 0)
|
||
|
|
die("Cannot read pipe: %m");
|
||
|
|
close(pipe_fd[0]);
|
||
|
|
}
|
||
|
|
|
||
|
|
// We still keep the PID file open and thus locked
|
||
|
|
body(dp);
|
||
|
|
exit(0);
|
||
|
|
}
|
||
|
|
|
||
|
|
// Write PID
|
||
|
|
if (dp->pid_file)
|
||
|
|
{
|
||
|
|
char buf[32];
|
||
|
|
int c = snprintf(buf, sizeof(buf), "%d\n", (int) pid);
|
||
|
|
ASSERT(c <= (int) sizeof(buf));
|
||
|
|
if (lseek(dp->pid_fd, 0, SEEK_SET) < 0 ||
|
||
|
|
write(dp->pid_fd, buf, c) != c ||
|
||
|
|
ftruncate(dp->pid_fd, c) ||
|
||
|
|
close(dp->pid_fd) < 0)
|
||
|
|
die("Cannot write PID to `%s': %m", dp->pid_file);
|
||
|
|
close(pipe_fd[0]);
|
||
|
|
close(pipe_fd[1]);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void
|
||
|
|
daemon_exit(struct daemon_params *dp)
|
||
|
|
{
|
||
|
|
if (dp->flags & DAEMON_FLAG_SIMULATE)
|
||
|
|
return;
|
||
|
|
|
||
|
|
if (dp->pid_file)
|
||
|
|
{
|
||
|
|
if (ftruncate(dp->pid_fd, 0))
|
||
|
|
die("Error truncating `%s': %m", dp->pid_file);
|
||
|
|
close(dp->pid_fd);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#ifdef TEST
|
||
|
|
|
||
|
|
#include <signal.h>
|
||
|
|
|
||
|
|
static volatile sig_atomic_t terminate;
|
||
|
|
|
||
|
|
static void term_handler(int sig UNUSED)
|
||
|
|
{
|
||
|
|
msg(L_INFO | L_SIGHANDLER, "SIGTERM received, terminating in a while");
|
||
|
|
terminate = 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void hup_handler(int sig UNUSED)
|
||
|
|
{
|
||
|
|
msg(L_INFO | L_SIGHANDLER, "SIGHUP received");
|
||
|
|
}
|
||
|
|
|
||
|
|
static void body(struct daemon_params *dp)
|
||
|
|
{
|
||
|
|
log_fork();
|
||
|
|
msg(L_INFO, "Daemon is running");
|
||
|
|
msg(L_INFO, "uid=%d/%d gid=%d/%d", (int) getuid(), (int) geteuid(), (int) getgid(), (int) getegid());
|
||
|
|
|
||
|
|
struct sigaction sa_term = { .sa_handler = term_handler };
|
||
|
|
struct sigaction sa_hup = { .sa_handler = hup_handler };
|
||
|
|
if (sigaction(SIGTERM, &sa_term, NULL) < 0 ||
|
||
|
|
sigaction(SIGHUP, &sa_hup, NULL) < 0)
|
||
|
|
ASSERT(0);
|
||
|
|
|
||
|
|
while (!terminate)
|
||
|
|
{
|
||
|
|
if (!sleep(60))
|
||
|
|
{
|
||
|
|
msg(L_INFO, "Timeout elapsed, terminating in a while");
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
sleep(2);
|
||
|
|
msg(L_INFO, "Daemon is shutting down");
|
||
|
|
daemon_exit(dp);
|
||
|
|
}
|
||
|
|
|
||
|
|
int main(int argc, char **argv)
|
||
|
|
{
|
||
|
|
struct daemon_params dp = {
|
||
|
|
.pid_file = "/tmp/123",
|
||
|
|
};
|
||
|
|
|
||
|
|
int opt;
|
||
|
|
while ((opt = getopt(argc, argv, "p:u:g:")) >= 0)
|
||
|
|
switch (opt)
|
||
|
|
{
|
||
|
|
case 'p':
|
||
|
|
dp.pid_file = optarg;
|
||
|
|
break;
|
||
|
|
case 'u':
|
||
|
|
dp.run_as_user = optarg;
|
||
|
|
break;
|
||
|
|
case 'g':
|
||
|
|
dp.run_as_group = optarg;
|
||
|
|
break;
|
||
|
|
default:
|
||
|
|
die("Invalid arguments");
|
||
|
|
}
|
||
|
|
|
||
|
|
daemon_init(&dp);
|
||
|
|
daemon_run(&dp, body);
|
||
|
|
msg(L_INFO, "Main program has ended");
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif
|