#include <sys/types.h>
+/** Parameters passed to the daemon helper. **/
struct daemon_params {
uns flags; // DAEMON_FLAG_xxx
const char *pid_file; // A path to PID file (optional)
int pid_fd;
};
+/** Flags passed to the daemon helper. **/
enum daemon_flags {
DAEMON_FLAG_PRESERVE_CWD = 1, // Skip chdir("/")
+ DAEMON_FLAG_SIMULATE = 2, // Simulate daemonization (avoid fork etc.)
};
/**
* a new process and does all necessary setup. Inside the new process, it calls
* @body (and when it returns, it exits the process). In the original process, it writes
* the PID file and returns.
+ *
+ * When `DAEMON_FLAG_SIMULATE` is set, it justs calls @body. This is useful
+ * for running of daemons in a debugger.
**/
void daemon_run(struct daemon_params *dp, void (*body)(struct daemon_params *dp));
**/
void daemon_exit(struct daemon_params *dp);
+#define DAEMON_ERR_LEN 256
+
+/** Parameters passed to daemon_control() **/
+struct daemon_control_params {
+ const char *pid_file; // A path to PID file
+ const char *guard_file; // A path to guard file
+ int action; // Action to perform (DAEMON_CONTROL_xxx)
+ char * const *argv; // Daemon's arguments, NULL-terminated (for DAEMON_CONTROL_START)
+ int signal; // Signal to send (for DAEMON_CONTROL_SIGNAL)
+ char error_msg[DAEMON_ERR_LEN]; // A detailed error message returned (for DAEMON_STATUS_ERROR)
+};
+
+enum daemon_control_action {
+ DAEMON_CONTROL_CHECK = 1,
+ DAEMON_CONTROL_START,
+ DAEMON_CONTROL_STOP,
+ DAEMON_CONTROL_SIGNAL,
+};
+
+/**
+ * Perform an action on a daemon:
+ *
+ * * `DAEMON_CONTROL_START` to start the daemon
+ * * `DAEMON_CONTROL_STOP` to stop the daemon (send `SIGTERM` or `dc->signal` if non-zero)
+ * * `DAEMON_CONTROL_CHECK` to check that the daemon is running
+ * * `DAEMON_CONTROL_SIGNAL` to send a signal to the daemon (send `SIGHUP` or `dc->signal` if non-zero)
+ *
+ * The function returns a status code:
+ *
+ * * `DAEMON_STATUS_OK` if the action has been performed successfully
+ * * `DAEMON_STATUS_ALREADY_DONE` if the daemon is already in the requested state
+ * * `DAEMON_STATUS_NOT_RUNNING` if the action failed, because the daemon is not running
+ * * `DAEMON_STATUS_ERROR` if the action failed for some other reason (in this case,
+ * `dc->error_msg` contains a full error message)
+ * * `DAEMON_STATUS_STALE` if the daemon was in an undefined state (e.g., a stale PID file);
+ * for `DAEMON_CONTROL_START`, it means success
+ **/
+enum daemon_control_status daemon_control(struct daemon_control_params *dc);
+
+// XXX: Also used as exit codes of the daemon-control utility.
+enum daemon_control_status {
+ DAEMON_STATUS_OK = 0,
+ DAEMON_STATUS_ALREADY_DONE = 100,
+ DAEMON_STATUS_NOT_RUNNING = 101,
+ DAEMON_STATUS_ERROR = 102,
+ DAEMON_STATUS_STALE = 103,
+};
+
#endif