librc: Complain when a real and virtual service have the same name

man/openrc-run.8

@@ -172,9 +172,9 @@ The service will start after these services and stop before these services.
 The service will start before these services and stop after these services.
 .It Ic provide
 The service provides this virtual service. For example, named provides dns.
-Virtual services take precedence over real services, so it is highly
-recommended that you do not have a real service that has the same name
-as a virtual service.
+Note that it is not legal to have a virtual and real service with the
+same name. If you do this, you will receive an error message, and you
+must rename either the real or virtual service.
 .It Ic config
 We should recalculate our dependencies if the listed files have changed.
 .It Ic keyword

src/librc/librc-depend.c

@@ -717,14 +717,16 @@ rc_deptree_update_needed(time_t *newest, char *file)
 }
 librc_hidden_def(rc_deptree_update_needed)
 
-/* This is a 6 phase operation
+/* This is a 7 phase operation
    Phase 1 is a shell script which loads each init script and config in turn
    and echos their dependency info to stdout
    Phase 2 takes that and populates a depinfo object with that data
    Phase 3 adds any provided services to the depinfo object
    Phase 4 scans that depinfo object and puts in backlinks
    Phase 5 removes broken before dependencies
-   Phase 6 saves the depinfo object to disk
+   Phase 6 looks for duplicate services indicating a real and virtual service
+   with the same names
+   Phase 7 saves the depinfo object to disk
    */
 bool
 rc_deptree_update(void)
@@ -733,7 +735,7 @@ rc_deptree_update(void)
 	RC_DEPTREE *deptree, *providers;
 	RC_DEPINFO *depinfo = NULL, *depinfo_np, *di;
 	RC_DEPTYPE *deptype = NULL, *dt_np, *dt, *provide;
-	RC_STRINGLIST *config, *types, *sorted, *visited;
+	RC_STRINGLIST *config, *dupes, *types, *sorted, *visited;
 	RC_STRING *s, *s2, *s2_np, *s3, *s4;
 	char *line = NULL;
 	size_t len = 0;
@@ -742,6 +744,7 @@ rc_deptree_update(void)
 	bool retval = true;
 	const char *sys = rc_sys();
 	struct utsname uts;
+	int serrno;
 
 	/* Some init scripts need RC_LIBEXECDIR to source stuff
 	   Ideally we should be setting our full env instead */
@@ -996,7 +999,22 @@ rc_deptree_update(void)
 	}
 	rc_stringlist_free(types);
 
-	/* Phase 6 - save to disk
+	/* Phase 6 - Print errors for duplicate services */
+	dupes = rc_stringlist_new();
+	TAILQ_FOREACH(depinfo, deptree, entries) {
+		serrno = errno;
+		errno = 0;
+		rc_stringlist_addu(dupes,depinfo->service);
+		if (errno == EEXIST) {
+			fprintf(stderr,
+					"Error: %s is the name of a real and virtual service.\n",
+					depinfo->service);
+		}
+		errno = serrno;
+	}
+	rc_stringlist_free(dupes);
+
+	/* Phase 7 - save to disk
 	   Now that we're purely in C, do we need to keep a shell parseable file?
 	   I think yes as then it stays human readable
 	   This works and should be entirely shell parseable provided that depend