allow instances to register ubus object that should be watched

[project/procd.git] / service / watch.c

diff --git a/service/watch.c b/service/watch.c
new file mode 100644 (file)
index 0000000..1d7cf78
--- /dev/null
+++ b/service/watch.c
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
+ * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1
+ * as published by the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <libubox/blobmsg_json.h>
+
+#include "../procd.h"
+
+struct watch_object {
+       struct list_head list;
+
+       void *id;
+       char *name;
+};
+
+struct watch_subscribe {
+       struct uloop_timeout t;
+       uint32_t id;
+};
+
+static struct ubus_event_handler watch_event;
+static struct ubus_subscriber watch_subscribe;
+static LIST_HEAD(watch_objects);
+
+static void watch_subscribe_cb(struct ubus_context *ctx, struct ubus_event_handler *ev,
+               const char *type, struct blob_attr *msg)
+{
+       static const struct blobmsg_policy policy = {
+               "path", BLOBMSG_TYPE_STRING
+       };
+       struct watch_object *o;
+       struct blob_attr *attr;
+       const char *path;
+
+       DEBUG(3, "ubus event %s\n", type);
+       if (strcmp(type, "ubus.object.add") != 0)
+               return;
+
+       blobmsg_parse(&policy, 1, &attr, blob_data(msg), blob_len(msg));
+       if (!attr)
+               return;
+
+       path = blobmsg_data(attr);
+       DEBUG(3, "ubus path %s\n", path);
+
+       list_for_each_entry(o, &watch_objects, list) {
+               unsigned int id;
+
+               if (strcmp(o->name, path))
+                       continue;
+               if (ubus_lookup_id(ctx, path, &id))
+                       continue;
+               if (!ubus_subscribe(ctx, &watch_subscribe, id))
+                       return;
+               ERROR("failed to suscribe %d\n", id);
+       }
+}
+
+void
+watch_add(const char *_name, void *id)
+{
+       int len = strlen(_name);
+       char *name;
+       struct watch_object *o = calloc_a(sizeof(*o), &name, len + 1);
+
+       o->name = name;
+       strcpy(name, _name);
+       o->id = id;
+       list_add(&o->list, &watch_objects);
+}
+
+void
+watch_del(void *id)
+{
+       struct watch_object *t, *n;
+
+       list_for_each_entry_safe(t, n, &watch_objects, list) {
+               if (t->id != id)
+                       continue;
+               list_del(&t->list);
+               free(t);
+       }
+}
+
+static int
+watch_notify_cb(struct ubus_context *ctx, struct ubus_object *obj,
+               struct ubus_request_data *req, const char *method,
+               struct blob_attr *msg)
+{
+       if (1 || debug >= 3) {
+               char *str;
+
+               str = blobmsg_format_json(msg, true);
+               LOG("Received ubus notify '%s': %s\n", method, str);
+               free(str);
+       }
+
+       trigger_event(method, msg);
+       return 0;
+}
+
+void
+watch_ubus(struct ubus_context *ctx)
+{
+       watch_event.cb = watch_subscribe_cb;
+       watch_subscribe.cb = watch_notify_cb;
+       if (ubus_register_event_handler(ctx, &watch_event, "ubus.object.add"))
+               ERROR("failed to add ubus event handler\n");
+       if (ubus_register_subscriber(ctx, &watch_subscribe))
+               ERROR("failed to register ubus subscriber\n");
+}