plugins: sys: drop conditions not affecting any svc_t

- Fix bug when calling sys_update_conds() when dir already exists
  and we're not being called from the scandir() handler.  I.e.,
  every time but the first for each new condition sub-family

- Drop sys conditions that don't affect any svc_t.  This may seem
  counterintuitive, and we should probably not use oneshot conds,
  but if we leave these conds asserted they may cause inadvertent
  trigger if a finit.conf is loaded which ha this sys cond.  E.g.,
  if ctrlaltdel is asserted and we enable a task in finit.conf and
  call `initctl reload`, the task would start immediately, even
  though ctrl-alt-del may have been pressed a week ago

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

plugins/sys.c

@@ -41,17 +41,31 @@ static int sys_add_path(struct iwatch *iw, char *path)
 	return iwatch_add(iw, path, IN_ONLYDIR | IN_CLOSE_WRITE);
 }
 
+/*
+ * unlink conditions with no active task/service, otherwise they may
+ * trigger inadvertently when calling `initctl reload` to activate
+ * a new configuration.
+ */
 static void sys_update_conds(char *dir, char *name, uint32_t mask)
 {
+	char path[256];
 	char *cond;
+	char *ptr;
 
-	cond = strstr(name, COND_BASE);
+	ptr = strrchr(name, '/');
+	if (ptr)
+		snprintf(path, sizeof(path), "%s/%s", dir, ++ptr);
+	else
+		snprintf(path, sizeof(path), "%s/%s", dir, name);
+
+	cond = strstr(path, COND_BASE);
 	if (!cond)
 		return;
 
 	cond += strlen(COND_BASE) + 1;
 	_d("cond: %s set: %d", cond, mask & IN_CREATE ? 1 : 0);
-	cond_update(cond);
+	if (!cond_update(cond))
+		unlink(path);
 }
 
 /* synthesize events in case of new run dirs */