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, *tmp;
  39
  40         list_for_each_entry_safe(ev, tmp, &obj->events, list) {
  41                 ubusd_delete_event_source(ev);
  42         }
  43 }
  44
  45 enum {
  46         EVREG_PATTERN,
  47         EVREG_OBJECT,
  48         EVREG_LAST,
  49 };
  50
  51 static struct blobmsg_policy evr_policy[] = {
  52         [EVREG_PATTERN] = { .name = "pattern", .type = BLOBMSG_TYPE_STRING },
  53         [EVREG_OBJECT] = { .name = "object", .type = BLOBMSG_TYPE_INT32 },
  54 };
  55
  56 static int ubusd_alloc_event_pattern(struct ubus_client *cl, struct blob_attr *msg)
  57 {
  58         struct event_source *ev;
  59         struct ubus_object *obj;
  60         struct blob_attr *attr[EVREG_LAST];
  61         char *pattern, *name;
  62         uint32_t id;
  63         bool partial = false;
  64         int len;
  65
  66         blobmsg_parse(evr_policy, EVREG_LAST, attr, blob_data(msg), blob_len(msg));
  67         if (!attr[EVREG_OBJECT] || !attr[EVREG_PATTERN])
  68                 return UBUS_STATUS_INVALID_ARGUMENT;
  69
  70         id = blobmsg_get_u32(attr[EVREG_OBJECT]);
  71         if (id < UBUS_SYSTEM_OBJECT_MAX)
  72                 return UBUS_STATUS_PERMISSION_DENIED;
  73
  74         obj = ubusd_find_object(id);
  75         if (!obj)
  76                 return UBUS_STATUS_NOT_FOUND;
  77
  78         if (obj->client != cl)
  79                 return UBUS_STATUS_PERMISSION_DENIED;
  80
  81         pattern = blobmsg_data(attr[EVREG_PATTERN]);
  82
  83         len = strlen(pattern);
  84         if (pattern[len - 1] == '*') {
  85                 partial = true;
  86                 pattern[len - 1] = 0;
  87                 len--;
  88         }
  89
  90         if (pattern[0] && ubusd_acl_check(cl, pattern, NULL, UBUS_ACL_LISTEN))
  91                 return UBUS_STATUS_PERMISSION_DENIED;
  92
  93         ev = calloc(1, sizeof(*ev) + len + 1);
  94         if (!ev)
  95                 return UBUS_STATUS_NO_DATA;
  96
  97         list_add(&ev->list, &obj->events);
  98         ev->obj = obj;
  99         ev->partial = partial;
 100         name = (char *) (ev + 1);
 101         strcpy(name, pattern);
 102         ev->avl.key = name;
 103         avl_insert(&patterns, &ev->avl);
 104
 105         return 0;
 106 }
 107
 108 static void ubusd_send_event_msg(struct ubus_msg_buf **ub, struct ubus_client *cl,
 109                                  struct ubus_object *obj, const char *id,
 110                                  event_fill_cb fill_cb, void *cb_priv)
 111 {
 112         uint32_t *objid_ptr;
 113
 114         /* do not loop back events */
 115         if (obj->client == cl)
 116             return;
 117
 118         /* do not send duplicate events */
 119         if (obj->event_seen == obj_event_seq)
 120                 return;
 121
 122         obj->event_seen = obj_event_seq;
 123
 124         if (!*ub) {
 125                 *ub = fill_cb(cb_priv, id);
 126                 (*ub)->hdr.type = UBUS_MSG_INVOKE;
 127                 (*ub)->hdr.peer = 0;
 128         }
 129
 130         objid_ptr = blob_data(blob_data((*ub)->data));
 131         *objid_ptr = htonl(obj->id.id);
 132
 133         (*ub)->hdr.seq = ++event_seq;
 134         ubus_msg_send(obj->client, *ub);
 135 }
 136
 137 int ubusd_send_event(struct ubus_client *cl, const char *id,
 138                      event_fill_cb fill_cb, void *cb_priv)
 139 {
 140         struct ubus_msg_buf *ub = NULL;
 141         struct event_source *ev;
 142         int match_len = 0;
 143
 144         if (ubusd_acl_check(cl, id, NULL, UBUS_ACL_SEND))
 145                 return UBUS_STATUS_PERMISSION_DENIED;
 146
 147         obj_event_seq++;
 148
 149         /*
 150          * Since this tree is sorted alphabetically, we can only expect to find
 151          * matching entries as long as the number of matching characters
 152          * between the pattern string and our string is monotonically increasing.
 153          */
 154         avl_for_each_element(&patterns, ev, avl) {
 155                 const char *key = ev->avl.key;
 156                 int cur_match_len;
 157                 bool full_match;
 158
 159                 full_match = ubus_strmatch_len(id, key, &cur_match_len);
 160                 if (cur_match_len < match_len)
 161                         break;
 162
 163                 match_len = cur_match_len;
 164
 165                 if (!full_match) {
 166                         if (!ev->partial)
 167                                 continue;
 168
 169                         if (match_len != (int) strlen(key))
 170                                 continue;
 171                 }
 172
 173                 ubusd_send_event_msg(&ub, cl, ev->obj, id, fill_cb, cb_priv);
 174         }
 175
 176         if (ub)
 177                 ubus_msg_free(ub);
 178
 179         return 0;
 180 }
 181
 182 enum {
 183         EVMSG_ID,
 184         EVMSG_DATA,
 185         EVMSG_LAST,
 186 };
 187
 188 static struct blobmsg_policy ev_policy[] = {
 189         [EVMSG_ID] = { .name = "id", .type = BLOBMSG_TYPE_STRING },
 190         [EVMSG_DATA] = { .name = "data", .type = BLOBMSG_TYPE_TABLE },
 191 };
 192
 193 static struct ubus_msg_buf *
 194 ubusd_create_event_from_msg(void *priv, const char *id)
 195 {
 196         struct blob_attr *msg = priv;
 197
 198         blob_buf_init(&b, 0);
 199         blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
 200         blob_put_string(&b, UBUS_ATTR_METHOD, id);
 201         blob_put(&b, UBUS_ATTR_DATA, blobmsg_data(msg), blobmsg_data_len(msg));
 202
 203         return ubus_msg_new(b.head, blob_raw_len(b.head), true);
 204 }
 205
 206 static int ubusd_forward_event(struct ubus_client *cl, struct blob_attr *msg)
 207 {
 208         struct blob_attr *data;
 209         struct blob_attr *attr[EVMSG_LAST];
 210         const char *id;
 211
 212         blobmsg_parse(ev_policy, EVMSG_LAST, attr, blob_data(msg), blob_len(msg));
 213         if (!attr[EVMSG_ID] || !attr[EVMSG_DATA])
 214                 return UBUS_STATUS_INVALID_ARGUMENT;
 215
 216         id = blobmsg_data(attr[EVMSG_ID]);
 217         data = attr[EVMSG_DATA];
 218
 219         if (!strncmp(id, "ubus.", 5))
 220                 return UBUS_STATUS_PERMISSION_DENIED;
 221
 222         return ubusd_send_event(cl, id, ubusd_create_event_from_msg, data);
 223 }
 224
 225 static int ubusd_event_recv(struct ubus_client *cl, struct ubus_msg_buf *ub, const char *method, struct blob_attr *msg)
 226 {
 227         if (!strcmp(method, "register"))
 228                 return ubusd_alloc_event_pattern(cl, msg);
 229
 230         if (!strcmp(method, "send"))
 231                 return ubusd_forward_event(cl, msg);
 232
 233         return UBUS_STATUS_INVALID_COMMAND;
 234 }
 235
 236 static struct ubus_msg_buf *
 237 ubusd_create_object_event_msg(void *priv, const char *id)
 238 {
 239         struct ubus_object *obj = priv;
 240         void *s;
 241
 242         blob_buf_init(&b, 0);
 243         blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
 244         blob_put_string(&b, UBUS_ATTR_METHOD, id);
 245         s = blob_nest_start(&b, UBUS_ATTR_DATA);
 246         blobmsg_add_u32(&b, "id", obj->id.id);
 247         blobmsg_add_string(&b, "path", obj->path.key);
 248         blob_nest_end(&b, s);
 249
 250         return ubus_msg_new(b.head, blob_raw_len(b.head), true);
 251 }
 252
 253 void ubusd_send_obj_event(struct ubus_object *obj, bool add)
 254 {
 255         const char *id = add ? "ubus.object.add" : "ubus.object.remove";
 256
 257         ubusd_send_event(NULL, id, ubusd_create_object_event_msg, obj);
 258 }
 259
 260 void ubusd_event_init(void)
 261 {
 262         ubus_init_string_tree(&patterns, true);
 263         event_obj = ubusd_create_object_internal(NULL, UBUS_SYSTEM_OBJECT_EVENT);
 264         if (event_obj != NULL)
 265                 event_obj->recv_msg = ubusd_event_recv;
 266 }
 267