ubusd_event.c

   1 /*
   2  * Copyright (C) 2011 Felix Fietkau <nbd@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License version 2.1
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <arpa/inet.h>
  15 #include "ubusd.h"
  16
  17 static struct avl_tree patterns;
  18 static struct ubus_object *event_obj;
  19 static int event_seq = 0;
  20 static int obj_event_seq = 1;
  21
  22 struct event_source {
  23         struct list_head list;
  24         struct ubus_object *obj;
  25         struct avl_node avl;
  26         bool partial;
  27 };
  28
  29 static void ubusd_delete_event_source(struct event_source *evs)
  30 {
  31         list_del(&evs->list);
  32         avl_delete(&patterns, &evs->avl);
  33         free(evs);
  34 }
  35
  36 void ubusd_event_cleanup_object(struct ubus_object *obj)
  37 {
  38         struct event_source *ev;
  39
  40         while (!list_empty(&obj->events)) {
  41                 ev = list_first_entry(&obj->events, struct event_source, list);
  42                 ubusd_delete_event_source(ev);
  43         }
  44 }
  45
  46 enum {
  47         EVREG_PATTERN,
  48         EVREG_OBJECT,
  49         EVREG_LAST,
  50 };
  51
  52 static struct blobmsg_policy evr_policy[] = {
  53         [EVREG_PATTERN] = { .name = "pattern", .type = BLOBMSG_TYPE_STRING },
  54         [EVREG_OBJECT] = { .name = "object", .type = BLOBMSG_TYPE_INT32 },
  55 };
  56
  57 static int ubusd_alloc_event_pattern(struct ubus_client *cl, struct blob_attr *msg)
  58 {
  59         struct event_source *ev;
  60         struct ubus_object *obj;
  61         struct blob_attr *attr[EVREG_LAST];
  62         char *pattern, *name;
  63         uint32_t id;
  64         bool partial = false;
  65         int len;
  66
  67         blobmsg_parse(evr_policy, EVREG_LAST, attr, blob_data(msg), blob_len(msg));
  68         if (!attr[EVREG_OBJECT] || !attr[EVREG_PATTERN])
  69                 return UBUS_STATUS_INVALID_ARGUMENT;
  70
  71         id = blobmsg_get_u32(attr[EVREG_OBJECT]);
  72         if (id < UBUS_SYSTEM_OBJECT_MAX)
  73                 return UBUS_STATUS_PERMISSION_DENIED;
  74
  75         obj = ubusd_find_object(id);
  76         if (!obj)
  77                 return UBUS_STATUS_NOT_FOUND;
  78
  79         if (obj->client != cl)
  80                 return UBUS_STATUS_PERMISSION_DENIED;
  81
  82         pattern = blobmsg_data(attr[EVREG_PATTERN]);
  83
  84         len = strlen(pattern);
  85         if (pattern[len - 1] == '*') {
  86                 partial = true;
  87                 pattern[len - 1] = 0;
  88                 len--;
  89         }
  90
  91         if (pattern[0] && ubusd_acl_check(cl, pattern, NULL, UBUS_ACL_LISTEN))
  92                 return UBUS_STATUS_PERMISSION_DENIED;
  93
  94         ev = calloc(1, sizeof(*ev) + len + 1);
  95         if (!ev)
  96                 return UBUS_STATUS_NO_DATA;
  97
  98         list_add(&ev->list, &obj->events);
  99         ev->obj = obj;
 100         ev->partial = partial;
 101         name = (char *) (ev + 1);
 102         strcpy(name, pattern);
 103         ev->avl.key = name;
 104         avl_insert(&patterns, &ev->avl);
 105
 106         return 0;
 107 }
 108
 109 static void ubusd_send_event_msg(struct ubus_msg_buf **ub, struct ubus_client *cl,
 110                                  struct ubus_object *obj, const char *id,
 111                                  event_fill_cb fill_cb, void *cb_priv)
 112 {
 113         uint32_t *objid_ptr;
 114
 115         /* do not loop back events */
 116         if (obj->client == cl)
 117             return;
 118
 119         /* do not send duplicate events */
 120         if (obj->event_seen == obj_event_seq)
 121                 return;
 122
 123         obj->event_seen = obj_event_seq;
 124
 125         if (!*ub) {
 126                 *ub = fill_cb(cb_priv, id);
 127                 (*ub)->hdr.type = UBUS_MSG_INVOKE;
 128                 (*ub)->hdr.peer = 0;
 129         }
 130
 131         objid_ptr = blob_data(blob_data((*ub)->data));
 132         *objid_ptr = htonl(obj->id.id);
 133
 134         (*ub)->hdr.seq = ++event_seq;
 135         ubus_msg_send(obj->client, *ub);
 136 }
 137
 138 int ubusd_send_event(struct ubus_client *cl, const char *id,
 139                      event_fill_cb fill_cb, void *cb_priv)
 140 {
 141         struct ubus_msg_buf *ub = NULL;
 142         struct event_source *ev;
 143         int match_len = 0;
 144
 145         obj_event_seq++;
 146
 147         /*
 148          * Since this tree is sorted alphabetically, we can only expect to find
 149          * matching entries as long as the number of matching characters
 150          * between the pattern string and our string is monotonically increasing.
 151          */
 152         avl_for_each_element(&patterns, ev, avl) {
 153                 const char *key = ev->avl.key;
 154                 int cur_match_len;
 155                 bool full_match;
 156
 157                 full_match = ubus_strmatch_len(id, key, &cur_match_len);
 158                 if (cur_match_len < match_len)
 159                         break;
 160
 161                 match_len = cur_match_len;
 162
 163                 if (!full_match) {
 164                         if (!ev->partial)
 165                                 continue;
 166
 167                         if (match_len != strlen(key))
 168                                 continue;
 169                 }
 170
 171                 ubusd_send_event_msg(&ub, cl, ev->obj, id, fill_cb, cb_priv);
 172         }
 173
 174         if (ub)
 175                 ubus_msg_free(ub);
 176
 177         return 0;
 178 }
 179
 180 enum {
 181         EVMSG_ID,
 182         EVMSG_DATA,
 183         EVMSG_LAST,
 184 };
 185
 186 static struct blobmsg_policy ev_policy[] = {
 187         [EVMSG_ID] = { .name = "id", .type = BLOBMSG_TYPE_STRING },
 188         [EVMSG_DATA] = { .name = "data", .type = BLOBMSG_TYPE_TABLE },
 189 };
 190
 191 static struct ubus_msg_buf *
 192 ubusd_create_event_from_msg(void *priv, const char *id)
 193 {
 194         struct blob_attr *msg = priv;
 195
 196         blob_buf_init(&b, 0);
 197         blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
 198         blob_put_string(&b, UBUS_ATTR_METHOD, id);
 199         blob_put(&b, UBUS_ATTR_DATA, blobmsg_data(msg), blobmsg_data_len(msg));
 200
 201         return ubus_msg_new(b.head, blob_raw_len(b.head), true);
 202 }
 203
 204 static int ubusd_forward_event(struct ubus_client *cl, struct blob_attr *msg)
 205 {
 206         struct blob_attr *data;
 207         struct blob_attr *attr[EVMSG_LAST];
 208         const char *id;
 209
 210         blobmsg_parse(ev_policy, EVMSG_LAST, attr, blob_data(msg), blob_len(msg));
 211         if (!attr[EVMSG_ID] || !attr[EVMSG_DATA])
 212                 return UBUS_STATUS_INVALID_ARGUMENT;
 213
 214         id = blobmsg_data(attr[EVMSG_ID]);
 215         data = attr[EVMSG_DATA];
 216
 217         if (!strncmp(id, "ubus.", 5))
 218                 return UBUS_STATUS_PERMISSION_DENIED;
 219
 220         return ubusd_send_event(cl, id, ubusd_create_event_from_msg, data);
 221 }
 222
 223 static int ubusd_event_recv(struct ubus_client *cl, struct ubus_msg_buf *ub, const char *method, struct blob_attr *msg)
 224 {
 225         if (!strcmp(method, "register"))
 226                 return ubusd_alloc_event_pattern(cl, msg);
 227
 228         if (!strcmp(method, "send"))
 229                 return ubusd_forward_event(cl, msg);
 230
 231         return UBUS_STATUS_INVALID_COMMAND;
 232 }
 233
 234 static struct ubus_msg_buf *
 235 ubusd_create_object_event_msg(void *priv, const char *id)
 236 {
 237         struct ubus_object *obj = priv;
 238         void *s;
 239
 240         blob_buf_init(&b, 0);
 241         blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
 242         blob_put_string(&b, UBUS_ATTR_METHOD, id);
 243         s = blob_nest_start(&b, UBUS_ATTR_DATA);
 244         blobmsg_add_u32(&b, "id", obj->id.id);
 245         blobmsg_add_string(&b, "path", obj->path.key);
 246         blob_nest_end(&b, s);
 247
 248         return ubus_msg_new(b.head, blob_raw_len(b.head), true);
 249 }
 250
 251 void ubusd_send_obj_event(struct ubus_object *obj, bool add)
 252 {
 253         const char *id = add ? "ubus.object.add" : "ubus.object.remove";
 254
 255         ubusd_send_event(NULL, id, ubusd_create_object_event_msg, obj);
 256 }
 257
 258 void ubusd_event_init(void)
 259 {
 260         ubus_init_string_tree(&patterns, true);
 261         event_obj = ubusd_create_object_internal(NULL, UBUS_SYSTEM_OBJECT_EVENT);
 262         if (event_obj != NULL)
 263                 event_obj->recv_msg = ubusd_event_recv;
 264 }
 265