ubus/libubus-sub.c
John Crispin b3e8c4ef07 Add auto subscribe support
Add a new property to ubus_subscriber called new_obj_cb. It gets called
everytime a new object appears on the bus. If the callback returns true,
libubus will automatically subscribe to the notifications.

Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
2023-11-14 22:29:04 +01:00

122 lines
3.3 KiB
C

/*
* Copyright (C) 2011-2012 Felix Fietkau <nbd@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 "libubus.h"
#include "libubus-internal.h"
static int ubus_subscriber_cb(struct ubus_context *ctx, struct ubus_object *obj,
struct ubus_request_data *req,
const char *method, struct blob_attr *msg)
{
struct ubus_subscriber *s;
s = container_of(obj, struct ubus_subscriber, obj);
if (s->cb)
return s->cb(ctx, obj, req, method, msg);
return 0;
}
const struct ubus_method watch_method __hidden = {
.name = NULL,
.handler = ubus_subscriber_cb,
};
static void
ubus_auto_sub_event_handler_cb(struct ubus_context *ctx, struct ubus_event_handler *ev,
const char *type, struct blob_attr *msg)
{
enum {
EVENT_ID,
EVENT_PATH,
__EVENT_MAX
};
static const struct blobmsg_policy event_policy[__EVENT_MAX] = {
[EVENT_ID] = { .name = "id", .type = BLOBMSG_TYPE_INT32 },
[EVENT_PATH] = { .name = "path", .type = BLOBMSG_TYPE_STRING },
};
struct blob_attr *tb[__EVENT_MAX];
struct ubus_subscriber *s;
const char *path;
int id;
blobmsg_parse(event_policy, __EVENT_MAX, tb, blob_data(msg), blob_len(msg));
if (!tb[EVENT_ID] || !tb[EVENT_PATH])
return;
path = blobmsg_get_string(tb[EVENT_PATH]);
id = blobmsg_get_u32(tb[EVENT_ID]);
list_for_each_entry(s, &ctx->auto_subscribers, list)
if (s->new_obj_cb(ctx, s, path))
ubus_subscribe(ctx, s, id);
}
static void
ubus_auto_sub_lookup(struct ubus_context *ctx, struct ubus_object_data *obj,
void *priv)
{
struct ubus_subscriber *s = priv;
if (s->new_obj_cb(ctx, s, obj->path))
ubus_subscribe(ctx, s, obj->id);
}
int ubus_register_subscriber(struct ubus_context *ctx, struct ubus_subscriber *s)
{
struct ubus_object *obj = &s->obj;
INIT_LIST_HEAD(&s->list);
obj->methods = &watch_method;
obj->n_methods = 1;
if (s->new_obj_cb) {
struct ubus_event_handler *ev = &ctx->auto_subscribe_event_handler;
list_add(&s->list, &ctx->auto_subscribers);
ev->cb = ubus_auto_sub_event_handler_cb;
if (!ev->obj.id)
ubus_register_event_handler(ctx, ev, "ubus.object.add");
ubus_lookup(ctx, NULL, ubus_auto_sub_lookup, s);
}
return ubus_add_object(ctx, obj);
}
static int
__ubus_subscribe_request(struct ubus_context *ctx, struct ubus_object *obj, uint32_t id, int type)
{
struct ubus_request req;
blob_buf_init(&b, 0);
blob_put_int32(&b, UBUS_ATTR_OBJID, obj->id);
blob_put_int32(&b, UBUS_ATTR_TARGET, id);
if (ubus_start_request(ctx, &req, b.head, type, 0) < 0)
return UBUS_STATUS_INVALID_ARGUMENT;
return ubus_complete_request(ctx, &req, 0);
}
int ubus_subscribe(struct ubus_context *ctx, struct ubus_subscriber *obj, uint32_t id)
{
return __ubus_subscribe_request(ctx, &obj->obj, id, UBUS_MSG_SUBSCRIBE);
}
int ubus_unsubscribe(struct ubus_context *ctx, struct ubus_subscriber *obj, uint32_t id)
{
return __ubus_subscribe_request(ctx, &obj->obj, id, UBUS_MSG_UNSUBSCRIBE);
}