Fix #282: add support for oncrash:script to call post:script action

This patch adds the oncrash:script option to call the post:script
action, if defined, for a crashing service.  The EXIT_CODE variable
sent to the script is set to `crashed`.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

doc/config.md

@@ -549,7 +549,8 @@ configurable with the following options:
     was originally designed for so not the default behavior
   * `oncrash:reboot` -- when all retries have failed, and the service
     has *crashed*, if this option is set the system is rebooted.
-    Note, future releases may include other `oncrash:` actions
+  * `oncrash:script` -- similarly, but instead of rebooting, call the
+    `post:script` action if set, see below.
 
 When stopping a service (run/task/sysv/service), either manually or
 when moving to another runlevel, Finit starts by sending `SIGTERM`, to

man/finit.conf.5

@@ -366,10 +366,21 @@ was originally designed for so not the default behavior.
 when all retries have failed, and the service
 has
 .Em crashed ,
-if this option is set the system is rebooted.  Note, future releases
-may include other
-.Cm oncrash:
-actions.
+if this option is set the system is rebooted.
+.It Cm oncrash:script
+Similar to
+.Cm oncrash:reboot ,
+but instead of rebooting this action calls the
+.Cm post:script
+(see below) to let the operator decide the best course of action.  If
+the post:script option is not set, this is a no-op.
+.Pp
+The post:script is called with the same environment variables
+.Sy except
+for the
+.Cm EXIT_CODE
+variable which is set to
+.Cm "crashed" .
 .El
 .Pp
 When stopping a service (run/task/sysv/service), either manually or when
@@ -412,11 +423,13 @@ or any unique identifier specified in the .conf file.  The
 .Cm post:script
 is called with an additional set of environment variables:
 .Bl -tag -offset indent -width 1n
-.It Cm EXIT_CODE=[exited,signal]
+.It Cm EXIT_CODE=[exited,signal,crashed]
 set to one of
-.Cm exited
+.Cm exited ,
+.Cm signal ,
 or
-.Cm signal
+.Cm crashed
+(see above).
 .It Cm EXIT_STATUS=[num,SIGNAME]
 set to one of exit status code from the program, if it exited normally,
 or the signal name (HUP, TERM, etc.) if it exited due to signal

src/service.c

@@ -1403,6 +1403,8 @@ int service_register(int type, char *cfg, struct rlimit rlimit[], char *file)
 		else if (MATCH_CMD(cmd, "oncrash:", arg)) {
 			if (MATCH_CMD(arg, "reboot", arg))
 				oncrash_action = SVC_ONCRASH_REBOOT;
+			if (MATCH_CMD(arg, "script", arg))
+				oncrash_action = SVC_ONCRASH_SCRIPT;
 		}
 		else if (MATCH_CMD(cmd, "respawn", arg))
 			respawn = 1;
@@ -1868,6 +1870,9 @@ static void service_post_script(svc_t *svc)
 			setenv("EXIT_STATUS", sig2str(sig), 1);
 		}
 
+		if (svc_is_crashing(svc))
+			setenv("EXIT_CODE", "crashed", 1);
+
 		execvp(_PATH_BSHELL, argv);
 		_exit(EX_OSERR);
 	}
@@ -1945,10 +1950,20 @@ static void service_retry(svc_t *svc)
 		      svc_ident(svc, NULL, 0));
 		svc_crashing(svc);
 		*restart_cnt = 0;
-		if (svc->oncrash_action == SVC_ONCRASH_REBOOT) {
+		switch (svc->oncrash_action) {
+		case SVC_ONCRASH_REBOOT:
 			logit(LOG_ERR, "%s issuing reboot", svc_ident(svc, NULL, 0));
 			sync();
 			kill(1, SIGTERM);
+			break;
+		case SVC_ONCRASH_SCRIPT:
+			if (svc_has_post(svc)) {
+				dbg("calling post:script %s, crashing.", svc->post_script);
+				service_post_script(svc);
+			}
+			break;
+		default:
+			break;
 		}
 		service_step(svc);
 		return;

src/svc.h

@@ -78,7 +78,8 @@ typedef enum {
 
 typedef enum {
 	SVC_ONCRASH_IGNORE = 0,
-	SVC_ONCRASH_REBOOT = 1,
+	SVC_ONCRASH_REBOOT,
+	SVC_ONCRASH_SCRIPT,
 } svc_oncrash_action_t;
 
 #define MAX_ID_LEN       16
@@ -260,6 +261,7 @@ static inline int  svc_is_updated  (svc_t *svc) { return svc &&  1 == svc->dirty
 static inline int  svc_is_blocked  (svc_t *svc) { return svc && svc->block != SVC_BLOCK_NONE; }
 static inline int  svc_is_busy     (svc_t *svc) { return svc && svc->block == SVC_BLOCK_BUSY; }
 static inline int  svc_is_missing  (svc_t *svc) { return svc && svc->block == SVC_BLOCK_MISSING; }
+static inline int  svc_is_crashing (svc_t *svc) { return svc && svc->block == SVC_BLOCK_CRASHING; }
 
 static inline void svc_unblock     (svc_t *svc) { if (svc) svc->block = SVC_BLOCK_NONE;       }
 #define            svc_start(svc)  svc_unblock(svc)