/*
* UCW Library -- Daemonization
*
- * (c) 2012 Martin Mares <mj@ucw.cz>
+ * (c) 2012--2014 Martin Mares <mj@ucw.cz>
*
* This software may be freely distributed and used according to the terms
* of the GNU Lesser General Public License.
#include <pwd.h>
#include <grp.h>
#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/file.h>
-static void daemon_resolve_ugid(struct daemon_params *dp)
+void
+daemon_resolve_ugid(struct daemon_params *dp)
{
// Resolve user name
const char *u = dp->run_as_user;
{
if (u[0] == '#')
{
- uns id;
- const char *err = str_to_uns(&id, u, NULL, 10 | STN_WHOLE);
+ 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;
{
if (g[0] == '#')
{
- uns id;
- const char *err = str_to_uns(&id, g, NULL, 10 | STN_WHOLE);
+ 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;
}
}
-void daemon_init(struct daemon_params *dp)
+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
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
- struct flock fl = { .l_type = F_WRLCK, .l_whence = SEEK_SET };
- if (fcntl(dp->pid_fd, F_SETLK, &fl) < 0)
+ if (flock(dp->pid_fd, LOCK_EX | LOCK_NB) < 0)
{
- if (errno == EAGAIN || errno == EACCES)
+ if (errno == EINTR || errno == EWOULDBLOCK)
die("Daemon is already running (`%s' locked)", dp->pid_file);
else
die("Cannot lock `%s': %m", dp->pid_file);
}
}
-void daemon_run(struct daemon_params *dp, void (*body)(struct daemon_params *dp))
+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
- 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);
+ daemon_switch_ugid(dp);
// Create a new session and close stdio
setsid();
die("Cannot fork: %m");
if (!pid)
{
- // The PID file is left open, so that it is kept locked
- // FIXME: Downgrade the lock to shared
+ // We still keep the PID file open and thus locked
body(dp);
exit(0);
}
-
- // Write PID and release the PID file
+
+ // Write PID
if (dp->pid_file)
{
char buf[32];
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) < 0 ||
+ ftruncate(dp->pid_fd, c) ||
close(dp->pid_fd) < 0)
die("Cannot write PID to `%s': %m", dp->pid_file);
}
}
-void daemon_exit(struct daemon_params *dp)
+void
+daemon_exit(struct daemon_params *dp)
{
+ if (dp->flags & DAEMON_FLAG_SIMULATE)
+ return;
+
if (dp->pid_file)
{
if (unlink(dp->pid_file) < 0)
#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");
- sleep(60);
+ 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(void)
+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");