From 4b752adba47e9c0bf0fc39d997e455049b62007a Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Wed, 18 Jul 2012 13:41:20 +0200
Subject: [PATCH] Daemon: Added DAEMON_STATUS_STALE

---
 ucw/daemon-ctrl.c          | 19 ++++++++++++-------
 ucw/daemon.h               |  3 +++
 ucw/utils/daemon-control.c |  1 +
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/ucw/daemon-ctrl.c b/ucw/daemon-ctrl.c
index 2a7908ae..21132e32 100644
--- a/ucw/daemon-ctrl.c
+++ b/ucw/daemon-ctrl.c
@@ -32,8 +32,10 @@ daemon_control_err(struct daemon_control_params *dc, char *msg, ...)
 }
 
 static int
-daemon_read_pid(struct daemon_control_params *dc, int will_wait)
+daemon_read_pid(struct daemon_control_params *dc, int will_wait, int *stalep)
 {
+  *stalep = 0;
+
   int pid_fd = open(dc->pid_file, O_RDONLY);
   if (pid_fd < 0)
     {
@@ -47,6 +49,7 @@ daemon_read_pid(struct daemon_control_params *dc, int will_wait)
     {
       // The lock file is stale
       close(pid_fd);
+      *stalep = 1;
       return 0;
     }
 
@@ -87,7 +90,7 @@ enum daemon_control_status
 daemon_control(struct daemon_control_params *dc)
 {
   enum daemon_control_status st = DAEMON_STATUS_ERROR;
-  int sig;
+  int sig, stale, stale2;
 
   int guard_fd = open(dc->guard_file, O_RDWR | O_CREAT, 0666);
   if (guard_fd < 0)
@@ -96,7 +99,7 @@ daemon_control(struct daemon_control_params *dc)
     return daemon_control_err(dc, "Cannot lock guard file `%s': %m", dc->guard_file);
 
   // Read the PID file
-  int pid = daemon_read_pid(dc, 0);
+  int pid = daemon_read_pid(dc, 0, &stale);
   if (pid < 0)
     goto done;
 
@@ -105,6 +108,8 @@ daemon_control(struct daemon_control_params *dc)
     case DAEMON_CONTROL_CHECK:
       if (pid)
 	st = DAEMON_STATUS_OK;
+      else if (stale)
+	st = DAEMON_STATUS_STALE;
       else
 	st = DAEMON_STATUS_NOT_RUNNING;
       break;
@@ -144,23 +149,23 @@ daemon_control(struct daemon_control_params *dc)
 	      daemon_control_err(dc, "Daemon %s %s", dc->argv[0], ecmsg);
 	      goto done;
 	    }
-	  pid = daemon_read_pid(dc, 0);
+	  pid = daemon_read_pid(dc, 0, &stale2);
 	  if (!pid)
 	    daemon_control_err(dc, "Daemon %s failed to write the PID file `%s'", dc->argv[0], dc->pid_file);
 	  else
-	    st = DAEMON_STATUS_OK;
+	    st = stale ? DAEMON_STATUS_STALE : DAEMON_STATUS_OK;
 	}
       break;
     case DAEMON_CONTROL_STOP:
       if (!pid)
-	return DAEMON_STATUS_ALREADY_DONE;
+	return stale ? DAEMON_STATUS_STALE : DAEMON_STATUS_ALREADY_DONE;
       sig = dc->signal ? : SIGTERM;
       if (kill(pid, sig) < 0)
 	{
 	  daemon_control_err(dc, "Cannot send signal %d: %m", sig);
 	  goto done;
 	}
-      pid = daemon_read_pid(dc, 1);
+      pid = daemon_read_pid(dc, 1, &stale2);
       ASSERT(pid <= 0);
       if (!pid)
 	st = DAEMON_STATUS_OK;
diff --git a/ucw/daemon.h b/ucw/daemon.h
index c99f8e08..9cdfe050 100644
--- a/ucw/daemon.h
+++ b/ucw/daemon.h
@@ -86,6 +86,8 @@ enum daemon_control_action {
  * * `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);
 
@@ -95,6 +97,7 @@ enum daemon_control_status {
   DAEMON_STATUS_ALREADY_DONE = 100,
   DAEMON_STATUS_NOT_RUNNING = 101,
   DAEMON_STATUS_ERROR = 102,
+  DAEMON_STATUS_STALE = 103,
 };
 
 #endif
diff --git a/ucw/utils/daemon-control.c b/ucw/utils/daemon-control.c
index 85fb4501..5174919b 100644
--- a/ucw/utils/daemon-control.c
+++ b/ucw/utils/daemon-control.c
@@ -56,6 +56,7 @@ Exit codes:\n\
 100			The action was null (e.g., --stop on a stopped daemon)\n\
 101			The daemon was not running (on --reload or --check)\n\
 102			The action has failed (error message was printed to stderr)\n\
+103			The daemon was in an undefined state (e.g., stale PID file)\n\
 ", stderr);
   exit(1);
 }
-- 
2.39.2