ubusd_event.c

Go to the documentation of this file.

/*
 * Copyright (C) 2011 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 <arpa/inet.h>
#include "ubusd.h"
 
static struct avl_tree patterns;
static struct ubus_object *event_obj;
static int event_seq = 0;
static int obj_event_seq = 1;
 
struct event_source {
        struct list_head list;
        struct ubus_object *obj;
        struct avl_node avl;
        bool partial;
};
 
static void ubusd_delete_event_source(struct event_source *evs)
{
        list_del(&evs->list);
        avl_delete(&patterns, &evs->avl);
        free(evs);
}
 
void ubusd_event_cleanup_object(struct ubus_object *obj)
{
        struct event_source *ev, *tmp;
 
        list_for_each_entry_safe(ev, tmp, &obj->events, list) {
                ubusd_delete_event_source(ev);
        }
}
 
enum {
        EVREG_PATTERN,
        EVREG_OBJECT,
        EVREG_LAST,
};
 
static struct blobmsg_policy evr_policy[] = {
        [EVREG_PATTERN] = { .name = "pattern", .type = BLOBMSG_TYPE_STRING },
        [EVREG_OBJECT] = { .name = "object", .type = BLOBMSG_TYPE_INT32 },
};
 
static int ubusd_alloc_event_pattern(struct ubus_client *cl, struct blob_attr *msg)
{
        struct event_source *ev;
        struct ubus_object *obj;
        struct blob_attr *attr[EVREG_LAST];
        char *pattern, *name;
        uint32_t id;
        bool partial = false;
        int len;
 
        if (!msg)
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        blobmsg_parse(evr_policy, EVREG_LAST, attr, blob_data(msg), blob_len(msg));
        if (!attr[EVREG_OBJECT] || !attr[EVREG_PATTERN])
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        id = blobmsg_get_u32(attr[EVREG_OBJECT]);
        if (id < UBUS_SYSTEM_OBJECT_MAX)
                return UBUS_STATUS_PERMISSION_DENIED;
 
        obj = ubusd_find_object(id);
        if (!obj)
                return UBUS_STATUS_NOT_FOUND;
 
        if (obj->client != cl)
                return UBUS_STATUS_PERMISSION_DENIED;
 
        pattern = blobmsg_data(attr[EVREG_PATTERN]);
 
        len = strlen(pattern);
        if (pattern[len - 1] == '*') {
                partial = true;
                pattern[len - 1] = 0;
                len--;
        }
 
        if (pattern[0] && ubusd_acl_check(cl, pattern, NULL, UBUS_ACL_LISTEN))
                return UBUS_STATUS_PERMISSION_DENIED;
 
        ev = calloc(1, sizeof(*ev) + len + 1);
        if (!ev)
                return UBUS_STATUS_NO_DATA;
 
        list_add(&ev->list, &obj->events);
        ev->obj = obj;
        ev->partial = partial;
        name = (char *) (ev + 1);
        strcpy(name, pattern);
        ev->avl.key = name;
        avl_insert(&patterns, &ev->avl);
 
        return 0;
}
 
static void ubusd_send_event_msg(struct ubus_msg_buf **ub, struct ubus_client *cl,
                                 struct ubus_object *obj, const char *id,
                                 event_fill_cb fill_cb, void *cb_priv)
{
        uint32_t *objid_ptr;
 
        /* do not loop back events */
        if (obj->client == cl)
            return;
 
        /* do not send duplicate events */
        if (obj->event_seen == obj_event_seq)
                return;
 
        obj->event_seen = obj_event_seq;
 
        if (!*ub) {
                *ub = fill_cb(cb_priv, id);
                (*ub)->hdr.type = UBUS_MSG_INVOKE;
                (*ub)->hdr.peer = 0;
        }
 
        objid_ptr = blob_data(blob_data((*ub)->data));
        *objid_ptr = htonl(obj->id.id);
 
        (*ub)->hdr.seq = ++event_seq;
        ubus_msg_send(obj->client, *ub);
}
 
int ubusd_send_event(struct ubus_client *cl, const char *id,
                     event_fill_cb fill_cb, void *cb_priv)
{
        struct ubus_msg_buf *ub = NULL;
        struct event_source *ev;
        int match_len = 0;
 
        if (ubusd_acl_check(cl, id, NULL, UBUS_ACL_SEND))
                return UBUS_STATUS_PERMISSION_DENIED;
 
        obj_event_seq++;
 
        /*
         * Since this tree is sorted alphabetically, we can only expect to find
         * matching entries as long as the number of matching characters
         * between the pattern string and our string is monotonically increasing.
         */
        avl_for_each_element(&patterns, ev, avl) {
                const char *key = ev->avl.key;
                int cur_match_len;
                bool full_match;
 
                full_match = ubus_strmatch_len(id, key, &cur_match_len);
                if (cur_match_len < match_len)
                        break;
 
                match_len = cur_match_len;
 
                if (!full_match) {
                        if (!ev->partial)
                                continue;
 
                        if (match_len != (int) strlen(key))
                                continue;
                }
 
                ubusd_send_event_msg(&ub, cl, ev->obj, id, fill_cb, cb_priv);
        }
 
        if (ub)
                ubus_msg_free(ub);
 
        return 0;
}
 
enum {
        EVMSG_ID,
        EVMSG_DATA,
        EVMSG_LAST,
};
 
static struct blobmsg_policy ev_policy[] = {
        [EVMSG_ID] = { .name = "id", .type = BLOBMSG_TYPE_STRING },
        [EVMSG_DATA] = { .name = "data", .type = BLOBMSG_TYPE_TABLE },
};
 
static struct ubus_msg_buf *
ubusd_create_event_from_msg(void *priv, const char *id)
{
        struct blob_attr *msg = priv;
 
        blob_buf_init(&b, 0);
        blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
        blob_put_string(&b, UBUS_ATTR_METHOD, id);
        blob_put(&b, UBUS_ATTR_DATA, blobmsg_data(msg), blobmsg_data_len(msg));
 
        return ubus_msg_new(b.head, blob_raw_len(b.head), true);
}
 
static int ubusd_forward_event(struct ubus_client *cl, struct blob_attr *msg)
{
        struct blob_attr *data;
        struct blob_attr *attr[EVMSG_LAST];
        const char *id;
 
        if (!msg)
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        blobmsg_parse(ev_policy, EVMSG_LAST, attr, blob_data(msg), blob_len(msg));
        if (!attr[EVMSG_ID] || !attr[EVMSG_DATA])
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        id = blobmsg_data(attr[EVMSG_ID]);
        data = attr[EVMSG_DATA];
 
        if (!strncmp(id, "ubus.", 5))
                return UBUS_STATUS_PERMISSION_DENIED;
 
        return ubusd_send_event(cl, id, ubusd_create_event_from_msg, data);
}
 
static int ubusd_event_recv(struct ubus_client *cl, struct ubus_msg_buf *ub, const char *method, struct blob_attr *msg)
{
        if (!strcmp(method, "register"))
                return ubusd_alloc_event_pattern(cl, msg);
 
        if (!strcmp(method, "send"))
                return ubusd_forward_event(cl, msg);
 
        return UBUS_STATUS_INVALID_COMMAND;
}
 
static struct ubus_msg_buf *
ubusd_create_object_event_msg(void *priv, const char *id)
{
        struct ubus_object *obj = priv;
        void *s;
 
        blob_buf_init(&b, 0);
        blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
        blob_put_string(&b, UBUS_ATTR_METHOD, id);
        s = blob_nest_start(&b, UBUS_ATTR_DATA);
        blobmsg_add_u32(&b, "id", obj->id.id);
        blobmsg_add_string(&b, "path", obj->path.key);
        blob_nest_end(&b, s);
 
        return ubus_msg_new(b.head, blob_raw_len(b.head), true);
}
 
void ubusd_send_obj_event(struct ubus_object *obj, bool add)
{
        const char *id = add ? "ubus.object.add" : "ubus.object.remove";
 
        ubusd_send_event(NULL, id, ubusd_create_object_event_msg, obj);
}
 
void ubusd_event_init(void)
{
        ubus_init_string_tree(&patterns, true);
        event_obj = ubusd_create_object_internal(NULL, UBUS_SYSTEM_OBJECT_EVENT);
        if (event_obj != NULL)
                event_obj->recv_msg = ubusd_event_recv;
}