Allow conflicting services to start when conflict is resolved

These changes add a new svc_block_t type: SVC_BLOCK_CONFLICT so a user
can more clearly see why a run/task/service has not been started by
Finit.  The reason for the block is by default logged, which can be
escaped by using the `nowarn` flag.

Also, when the conflict is resolved, allow the service to start.

With these changes, the system/hotplug.conf should work better and
cause less questions about "strange" log messages.

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

Author: troglobit

src/api.c

@@ -65,6 +65,7 @@ static int stop(svc_t *svc, void *user_data)
 	service_timeout_cancel(svc);
 	svc_stop(svc);
 	service_step(svc);
+	service_step_all(SVC_TYPE_ANY);
 
 	return 0;
 }
@@ -77,6 +78,7 @@ static int start(svc_t *svc, void *user_data)
 	service_timeout_cancel(svc);
 	svc_start(svc);
 	service_step(svc);
+	service_step_all(SVC_TYPE_ANY);
 
 	return 0;
 }

src/service.c

@@ -610,13 +610,6 @@ static int service_start(svc_t *svc)
 		}
 	}
 
-	/* Don't start if it conflicts with something else already started */
-	if (svc_conflicts(svc)) {
-		logit(LOG_INFO, "Not starting %s, conflicts with %s",
-		      svc_ident(svc, NULL, 0), svc->conflict);
-		return 1;
-	}
-
 	compose_cmdline(svc, cmdline, sizeof(cmdline));
 	if (svc_is_sysv(svc))
 		logit(LOG_CONSOLE | LOG_NOTICE, "Calling '%s start' ...", cmdline);
@@ -1737,6 +1730,7 @@ int service_register(int type, char *cfg, struct rlimit rlimit[], char *file)
 	else
 		memset(svc->ifstmt, 0, sizeof(svc->ifstmt));
 	svc->manual  = manual;
+	svc->nowarn  = nowarn;
 	svc->respawn = respawn;
 	svc->forking = forking;
 	svc->restart_max = restart_max;
@@ -2276,6 +2270,15 @@ int service_step(svc_t *svc)
 	case SVC_HALTED_STATE:
 		if (enabled)
 			svc_set_state(svc, SVC_WAITING_STATE);
+		else {
+			if (svc_is_conflict(svc)) {
+				logit(svc->nowarn ? LOG_DEBUG : LOG_INFO,
+				      "%s in conflict with %s, checking again ...",
+				      svc_ident(svc, NULL, 0), svc->conflict);
+				if (!svc_conflicts(svc))
+					svc_unblock(svc);
+			}
+		}
 		break;
 
 	case SVC_DONE_STATE:
@@ -2342,6 +2345,16 @@ int service_step(svc_t *svc)
 			if (sm_is_in_teardown(&sm))
 				break;
 
+			/* Don't start if it conflicts with something else already started */
+			if (svc_conflicts(svc)) {
+				logit(svc->nowarn ? LOG_DEBUG : LOG_INFO,
+				      "Not starting %s, conflicts with %s",
+				      svc_ident(svc, NULL, 0), svc->conflict);
+				svc_conflict(svc);
+				svc_set_state(svc, SVC_HALTED_STATE);
+				break;
+			}
+
 			if (svc_has_pre(svc)) {
 				svc_set_state(svc, SVC_SETUP_STATE);
 				service_pre_script(svc);

src/svc.h

@@ -74,6 +74,7 @@ typedef enum {
 	SVC_BLOCK_USER,
 	SVC_BLOCK_BUSY,
 	SVC_BLOCK_RESTARTING,
+	SVC_BLOCK_CONFLICT,
 } svc_block_t;
 
 typedef enum {
@@ -125,6 +126,7 @@ typedef struct svc {
 	svc_type_t     type;	       /* Service, run, task, ... */
 	char           protect;        /* Services like dbus-daemon & udev by Finit */
 	char           manual;	       /* run/task that require `initctl start foo` */
+	char           nowarn;	       /* Skip or log warning if cmd missing or conflicts */
 	const int      dirty;	       /* 0: unmodified, 1: modified */
 	const int      removed;
 	int            starting;       /* ... waiting for pidfile to be re-asserted */
@@ -270,6 +272,7 @@ static inline int  svc_is_busy     (svc_t *svc) { return svc && svc->block == SV
 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 int  svc_is_restart  (svc_t *svc) { return svc && svc->block == SVC_BLOCK_RESTARTING; }
+static inline int  svc_is_conflict (svc_t *svc) { return svc && svc->block == SVC_BLOCK_CONFLICT; }
 
 static inline void svc_unblock     (svc_t *svc) { if (svc) svc->block = SVC_BLOCK_NONE;       }
 #define            svc_start(svc)  svc_unblock(svc)
@@ -278,6 +281,7 @@ static inline void svc_busy        (svc_t *svc) { if (svc) svc->block = SVC_BLOC
 static inline void svc_missing     (svc_t *svc) { if (svc) svc->block = SVC_BLOCK_MISSING; }
 static inline void svc_restarting  (svc_t *svc) { if (svc) svc->block = SVC_BLOCK_RESTARTING; }
 static inline void svc_crashing    (svc_t *svc) { if (svc) svc->block = SVC_BLOCK_CRASHING; }
+static inline void svc_conflict    (svc_t *svc) { if (svc) svc->block = SVC_BLOCK_CONFLICT; }
 
 /* Has condition in configuration and cond is allowed? */
 static inline int svc_has_cond(svc_t *svc)
@@ -350,6 +354,9 @@ static inline char *svc_status(svc_t *svc)
 
 		case SVC_BLOCK_RESTARTING:
 			return "restart";
+		case SVC_BLOCK_CONFLICT:
+			return "conflict";
+
 		}
 		return "unknown";