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         if (!msg)
  67                 return UBUS_STATUS_INVALID_ARGUMENT;
  68
  69         blobmsg_parse(evr_policy, EVREG_LAST, attr, blob_data(msg), blob_len(msg));
  70         if (!attr[EVREG_OBJECT] || !attr[EVREG_PATTERN])
  71                 return UBUS_STATUS_INVALID_ARGUMENT;
  72
  73         id = blobmsg_get_u32(attr[EVREG_OBJECT]);
  74         if (id < UBUS_SYSTEM_OBJECT_MAX)
  75                 return UBUS_STATUS_PERMISSION_DENIED;
  76
  77         obj = ubusd_find_object(id);
  78         if (!obj)
  79                 return UBUS_STATUS_NOT_FOUND;
  80
  81         if (obj->client != cl)
  82                 return UBUS_STATUS_PERMISSION_DENIED;
  83
  84         pattern = blobmsg_data(attr[EVREG_PATTERN]);
  85
  86         len = strlen(pattern);
  87         if (pattern[len - 1] == '*') {
  88                 partial = true;
  89                 pattern[len - 1] = 0;
  90                 len--;
  91         }
  92
  93         if (pattern[0] && ubusd_acl_check(cl, pattern, NULL, UBUS_ACL_LISTEN))
  94                 return UBUS_STATUS_PERMISSION_DENIED;
  95
  96         ev = calloc(1, sizeof(*ev) + len + 1);
  97         if (!ev)
  98                 return UBUS_STATUS_NO_DATA;
  99
 100         list_add(&ev->list, &obj->events);
 101         ev->obj = obj;
 102         ev->partial = partial;
 103         name = (char *) (ev + 1);
 104         strcpy(name, pattern);
 105         ev->avl.key = name;
 106         avl_insert(&patterns, &ev->avl);
 107
 108         return 0;
 109 }
 110
 111 static void ubusd_send_event_msg(struct ubus_msg_buf **ub, struct ubus_client *cl,
 112                                  struct ubus_object *obj, const char *id,
 113                                  event_fill_cb fill_cb, void *cb_priv)
 114 {
 115         uint32_t *objid_ptr;
 116
 117         /* do not loop back events */
 118         if (obj->client == cl)
 119             return;
 120
 121         /* do not send duplicate events */
 122         if (obj->event_seen == obj_event_seq)
 123                 return;
 124
 125         obj->event_seen = obj_event_seq;
 126
 127         if (!*ub) {
 128                 *ub = fill_cb(cb_priv, id);
 129                 (*ub)->hdr.type = UBUS_MSG_INVOKE;
 130                 (*ub)->hdr.peer = 0;
 131         }
 132
 133         objid_ptr = blob_data(blob_data((*ub)->data));
 134         *objid_ptr = htonl(obj->id.id);
 135
 136         (*ub)->hdr.seq = ++event_seq;
 137         ubus_msg_send(obj->client, *ub);
 138 }
 139
 140 int ubusd_send_event(struct ubus_client *cl, const char *id,
 141                      event_fill_cb fill_cb, void *cb_priv)
 142 {
 143         struct ubus_msg_buf *ub = NULL;
 144         struct event_source *ev;
 145         int match_len = 0;
 146
 147         if (ubusd_acl_check(cl, id, NULL, UBUS_ACL_SEND))
 148                 return UBUS_STATUS_PERMISSION_DENIED;
 149
 150         obj_event_seq++;
 151
 152         /*
 153          * Since this tree is sorted alphabetically, we can only expect to find
 154          * matching entries as long as the number of matching characters
 155          * between the pattern string and our string is monotonically increasing.
 156          */
 157         avl_for_each_element(&patterns, ev, avl) {
 158                 const char *key = ev->avl.key;
 159                 int cur_match_len;
 160                 bool full_match;
 161
 162                 full_match = ubus_strmatch_len(id, key, &cur_match_len);
 163                 if (cur_match_len < match_len)
 164                         break;
 165
 166                 match_len = cur_match_len;
 167
 168                 if (!full_match) {
 169                         if (!ev->partial)
 170                                 continue;
 171
 172                         if (match_len != (int) strlen(key))
 173                                 continue;
 174                 }
 175
 176                 ubusd_send_event_msg(&ub, cl, ev->obj, id, fill_cb, cb_priv);
 177         }
 178
 179         if (ub)
 180                 ubus_msg_free(ub);
 181
 182         return 0;
 183 }
 184
 185 enum {
 186         EVMSG_ID,
 187         EVMSG_DATA,
 188         EVMSG_LAST,
 189 };
 190
 191 static struct blobmsg_policy ev_policy[] = {
 192         [EVMSG_ID] = { .name = "id", .type = BLOBMSG_TYPE_STRING },
 193         [EVMSG_DATA] = { .name = "data", .type = BLOBMSG_TYPE_TABLE },
 194 };
 195
 196 static struct ubus_msg_buf *
 197 ubusd_create_event_from_msg(void *priv, const char *id)
 198 {
 199         struct blob_attr *msg = priv;
 200
 201         blob_buf_init(&b, 0);
 202         blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
 203         blob_put_string(&b, UBUS_ATTR_METHOD, id);
 204         blob_put(&b, UBUS_ATTR_DATA, blobmsg_data(msg), blobmsg_data_len(msg));
 205
 206         return ubus_msg_new(b.head, blob_raw_len(b.head), true);
 207 }
 208
 209 static int ubusd_forward_event(struct ubus_client *cl, struct blob_attr *msg)
 210 {
 211         struct blob_attr *data;
 212         struct blob_attr *attr[EVMSG_LAST];
 213         const char *id;
 214
 215         if (!msg)
 216                 return UBUS_STATUS_INVALID_ARGUMENT;
 217
 218         blobmsg_parse(ev_policy, EVMSG_LAST, attr, blob_data(msg), blob_len(msg));
 219         if (!attr[EVMSG_ID] || !attr[EVMSG_DATA])
 220                 return UBUS_STATUS_INVALID_ARGUMENT;
 221
 222         id = blobmsg_data(attr[EVMSG_ID]);
 223         data = attr[EVMSG_DATA];
 224
 225         if (!strncmp(id, "ubus.", 5))
 226                 return UBUS_STATUS_PERMISSION_DENIED;
 227
 228         return ubusd_send_event(cl, id, ubusd_create_event_from_msg, data);
 229 }
 230
 231 static int ubusd_event_recv(struct ubus_client *cl, struct ubus_msg_buf *ub, const char *method, struct blob_attr *msg)
 232 {
 233         if (!strcmp(method, "register"))
 234                 return ubusd_alloc_event_pattern(cl, msg);
 235
 236         if (!strcmp(method, "send"))
 237                 return ubusd_forward_event(cl, msg);
 238
 239         return UBUS_STATUS_INVALID_COMMAND;
 240 }
 241
 242 static struct ubus_msg_buf *
 243 ubusd_create_object_event_msg(void *priv, const char *id)
 244 {
 245         struct ubus_object *obj = priv;
 246         void *s;
 247
 248         blob_buf_init(&b, 0);
 249         blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
 250         blob_put_string(&b, UBUS_ATTR_METHOD, id);
 251         s = blob_nest_start(&b, UBUS_ATTR_DATA);
 252         blobmsg_add_u32(&b, "id", obj->id.id);
 253         blobmsg_add_string(&b, "path", obj->path.key);
 254         blob_nest_end(&b, s);
 255
 256         return ubus_msg_new(b.head, blob_raw_len(b.head), true);
 257 }
 258
 259 void ubusd_send_obj_event(struct ubus_object *obj, bool add)
 260 {
 261         const char *id = add ? "ubus.object.add" : "ubus.object.remove";
 262
 263         ubusd_send_event(NULL, id, ubusd_create_object_event_msg, obj);
 264 }
 265
 266 void ubusd_event_init(void)
 267 {
 268         ubus_init_string_tree(&patterns, true);
 269         event_obj = ubusd_create_object_internal(NULL, UBUS_SYSTEM_OBJECT_EVENT);
 270         if (event_obj != NULL)
 271                 event_obj->recv_msg = ubusd_event_recv;
 272 }
 273