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         ev = calloc(1, sizeof(*ev) + len + 1);
  92         if (!ev)
  93                 return UBUS_STATUS_NO_DATA;
  94
  95         list_add(&ev->list, &obj->events);
  96         ev->obj = obj;
  97         ev->partial = partial;
  98         name = (char *) (ev + 1);
  99         strcpy(name, pattern);
 100         ev->avl.key = name;
 101         avl_insert(&patterns, &ev->avl);
 102
 103         return 0;
 104 }
 105
 106 static void ubusd_send_event_msg(struct ubus_msg_buf **ub, struct ubus_client *cl,
 107                                  struct ubus_object *obj, const char *id,
 108                                  event_fill_cb fill_cb, void *cb_priv)
 109 {
 110         uint32_t *objid_ptr;
 111
 112         /* do not loop back events */
 113         if (obj->client == cl)
 114             return;
 115
 116         /* do not send duplicate events */
 117         if (obj->event_seen == obj_event_seq)
 118                 return;
 119
 120         obj->event_seen = obj_event_seq;
 121
 122         if (!*ub) {
 123                 *ub = fill_cb(cb_priv, id);
 124                 (*ub)->hdr.type = UBUS_MSG_INVOKE;
 125                 (*ub)->hdr.peer = 0;
 126         }
 127
 128         objid_ptr = blob_data(blob_data((*ub)->data));
 129         *objid_ptr = htonl(obj->id.id);
 130
 131         (*ub)->hdr.seq = ++event_seq;
 132         ubus_msg_send(obj->client, *ub, false);
 133 }
 134
 135 static bool strmatch_len(const char *s1, const char *s2, int *len)
 136 {
 137         for (*len = 0; s1[*len] == s2[*len]; (*len)++)
 138                 if (!s1[*len])
 139                         return true;
 140
 141         return false;
 142 }
 143
 144 int ubusd_send_event(struct ubus_client *cl, const char *id,
 145                      event_fill_cb fill_cb, void *cb_priv)
 146 {
 147         struct ubus_msg_buf *ub = NULL;
 148         struct event_source *ev;
 149         int match_len = 0;
 150
 151         obj_event_seq++;
 152
 153         /*
 154          * Since this tree is sorted alphabetically, we can only expect to find
 155          * matching entries as long as the number of matching characters
 156          * between the pattern string and our string is monotonically increasing.
 157          */
 158         avl_for_each_element(&patterns, ev, avl) {
 159                 const char *key = ev->avl.key;
 160                 int cur_match_len;
 161                 bool full_match;
 162
 163                 full_match = strmatch_len(id, key, &cur_match_len);
 164                 if (cur_match_len < match_len)
 165                         break;
 166
 167                 match_len = cur_match_len;
 168
 169                 if (!full_match) {
 170                         if (!ev->partial)
 171                                 continue;
 172
 173                         if (match_len != strlen(key))
 174                                 continue;
 175                 }
 176
 177                 ubusd_send_event_msg(&ub, cl, ev->obj, id, fill_cb, cb_priv);
 178         }
 179
 180         if (ub)
 181                 ubus_msg_free(ub);
 182
 183         return 0;
 184 }
 185
 186 enum {
 187         EVMSG_ID,
 188         EVMSG_DATA,
 189         EVMSG_LAST,
 190 };
 191
 192 static struct blobmsg_policy ev_policy[] = {
 193         [EVMSG_ID] = { .name = "id", .type = BLOBMSG_TYPE_STRING },
 194         [EVMSG_DATA] = { .name = "data", .type = BLOBMSG_TYPE_TABLE },
 195 };
 196
 197 static struct ubus_msg_buf *
 198 ubusd_create_event_from_msg(void *priv, const char *id)
 199 {
 200         struct blob_attr *msg = priv;
 201
 202         blob_buf_init(&b, 0);
 203         blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
 204         blob_put_string(&b, UBUS_ATTR_METHOD, id);
 205         blob_put(&b, UBUS_ATTR_DATA, blobmsg_data(msg), blobmsg_data_len(msg));
 206
 207         return ubus_msg_new(b.head, blob_raw_len(b.head), true);
 208 }
 209
 210 static int ubusd_forward_event(struct ubus_client *cl, struct blob_attr *msg)
 211 {
 212         struct blob_attr *data;
 213         struct blob_attr *attr[EVMSG_LAST];
 214         const char *id;
 215
 216         blobmsg_parse(ev_policy, EVMSG_LAST, attr, blob_data(msg), blob_len(msg));
 217         if (!attr[EVMSG_ID] || !attr[EVMSG_DATA])
 218                 return UBUS_STATUS_INVALID_ARGUMENT;
 219
 220         id = blobmsg_data(attr[EVMSG_ID]);
 221         data = attr[EVMSG_DATA];
 222
 223         if (!strncmp(id, "ubus.", 5))
 224                 return UBUS_STATUS_PERMISSION_DENIED;
 225
 226         return ubusd_send_event(cl, id, ubusd_create_event_from_msg, data);
 227 }
 228
 229 static int ubusd_event_recv(struct ubus_client *cl, struct ubus_msg_buf *ub, const char *method, struct blob_attr *msg)
 230 {
 231         if (!strcmp(method, "register"))
 232                 return ubusd_alloc_event_pattern(cl, msg);
 233
 234         if (!strcmp(method, "send"))
 235                 return ubusd_forward_event(cl, msg);
 236
 237         return UBUS_STATUS_INVALID_COMMAND;
 238 }
 239
 240 static struct ubus_msg_buf *
 241 ubusd_create_object_event_msg(void *priv, const char *id)
 242 {
 243         struct ubus_object *obj = priv;
 244         void *s;
 245
 246         blob_buf_init(&b, 0);
 247         blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
 248         blob_put_string(&b, UBUS_ATTR_METHOD, id);
 249         s = blob_nest_start(&b, UBUS_ATTR_DATA);
 250         blobmsg_add_u32(&b, "id", obj->id.id);
 251         blobmsg_add_string(&b, "path", obj->path.key);
 252         blob_nest_end(&b, s);
 253
 254         return ubus_msg_new(b.head, blob_raw_len(b.head), true);
 255 }
 256
 257 void ubusd_send_obj_event(struct ubus_object *obj, bool add)
 258 {
 259         const char *id = add ? "ubus.object.add" : "ubus.object.remove";
 260
 261         ubusd_send_event(NULL, id, ubusd_create_object_event_msg, obj);
 262 }
 263
 264 void ubusd_event_init(void)
 265 {
 266         ubus_init_string_tree(&patterns, true);
 267         event_obj = ubusd_create_object_internal(NULL, UBUS_SYSTEM_OBJECT_EVENT);
 268         if (event_obj != NULL)
 269                 event_obj->recv_msg = ubusd_event_recv;
 270 }
 271