ubusd_event.c

   1 #include <arpa/inet.h>
   2 #include "ubusd.h"
   3
   4 static struct avl_tree patterns;
   5 static struct ubus_object *event_obj;
   6 static int event_seq = 0;
   7 static int obj_event_seq = 1;
   8
   9 struct event_source {
  10         struct list_head list;
  11         struct ubus_object *obj;
  12         struct avl_node avl;
  13         bool partial;
  14 };
  15
  16 static void ubusd_delete_event_source(struct event_source *evs)
  17 {
  18         list_del(&evs->list);
  19         avl_delete(&patterns, &evs->avl);
  20         free(evs);
  21 }
  22
  23 void ubusd_event_cleanup_object(struct ubus_object *obj)
  24 {
  25         struct event_source *ev;
  26
  27         while (!list_empty(&obj->events)) {
  28                 ev = list_first_entry(&obj->events, struct event_source, list);
  29                 ubusd_delete_event_source(ev);
  30         }
  31 }
  32
  33 enum {
  34         EVREG_PATTERN,
  35         EVREG_OBJECT,
  36         EVREG_LAST,
  37 };
  38
  39 static struct blobmsg_policy evr_policy[] = {
  40         [EVREG_PATTERN] = { .name = "pattern", .type = BLOBMSG_TYPE_STRING },
  41         [EVREG_OBJECT] = { .name = "object", .type = BLOBMSG_TYPE_INT32 },
  42 };
  43
  44 static int ubusd_alloc_event_pattern(struct ubus_client *cl, struct blob_attr *msg)
  45 {
  46         struct event_source *ev;
  47         struct ubus_object *obj;
  48         struct blob_attr *attr[EVREG_LAST];
  49         char *pattern;
  50         uint32_t id;
  51         bool partial = false;
  52         int len;
  53
  54         blobmsg_parse(evr_policy, EVREG_LAST, attr, blob_data(msg), blob_len(msg));
  55         if (!attr[EVREG_OBJECT] || !attr[EVREG_PATTERN])
  56                 return UBUS_STATUS_INVALID_ARGUMENT;
  57
  58         id = blobmsg_get_u32(attr[EVREG_OBJECT]);
  59         if (id < UBUS_SYSTEM_OBJECT_MAX)
  60                 return UBUS_STATUS_PERMISSION_DENIED;
  61
  62         obj = ubusd_find_object(id);
  63         if (!obj)
  64                 return UBUS_STATUS_NOT_FOUND;
  65
  66         if (obj->client != cl)
  67                 return UBUS_STATUS_PERMISSION_DENIED;
  68
  69         pattern = blobmsg_data(attr[EVREG_PATTERN]);
  70
  71         len = strlen(pattern);
  72         if (pattern[len - 1] == '*') {
  73                 partial = true;
  74                 pattern[len - 1] = 0;
  75                 len--;
  76         }
  77
  78         ev = calloc(1, sizeof(*ev) + len + 1);
  79         if (!ev)
  80                 return UBUS_STATUS_NO_DATA;
  81
  82         list_add(&ev->list, &obj->events);
  83         ev->obj = obj;
  84         ev->partial = partial;
  85         ev->avl.key = (void *) (ev + 1);
  86         strcpy(ev->avl.key, pattern);
  87         avl_insert(&patterns, &ev->avl);
  88
  89         return 0;
  90 }
  91
  92 typedef struct ubus_msg_buf *(*event_fill_cb)(void *priv, const char *id);
  93
  94 static void ubusd_send_event_msg(struct ubus_msg_buf **ub, struct ubus_client *cl,
  95                                  struct ubus_object *obj, const char *id,
  96                                  event_fill_cb fill_cb, void *cb_priv)
  97 {
  98         uint32_t *objid_ptr;
  99
 100         /* do not loop back events */
 101         if (obj->client == cl)
 102             return;
 103
 104         /* do not send duplicate events */
 105         if (obj->event_seen == obj_event_seq)
 106                 return;
 107
 108         obj->event_seen = obj_event_seq;
 109
 110         if (!*ub) {
 111                 *ub = fill_cb(cb_priv, id);
 112                 (*ub)->hdr.type = UBUS_MSG_INVOKE;
 113                 (*ub)->hdr.peer = 0;
 114         }
 115
 116         objid_ptr = blob_data(blob_data((*ub)->data));
 117         *objid_ptr = htonl(obj->id.id);
 118
 119         (*ub)->hdr.seq = ++event_seq;
 120         ubus_msg_send(obj->client, *ub, false);
 121 }
 122
 123 bool strmatch_len(const char *s1, const char *s2, int *len)
 124 {
 125         for (*len = 0; s1[*len] == s2[*len]; (*len)++)
 126                 if (!s1[*len])
 127                         return true;
 128
 129         return false;
 130 }
 131
 132 static int ubusd_send_event(struct ubus_client *cl, const char *id,
 133                             event_fill_cb fill_cb, void *cb_priv)
 134 {
 135         struct ubus_msg_buf *ub = NULL;
 136         struct event_source *ev;
 137         int match_len = 0;
 138
 139         obj_event_seq++;
 140
 141         /*
 142          * Since this tree is sorted alphabetically, we can only expect to find
 143          * matching entries as long as the number of matching characters
 144          * between the pattern string and our string is monotonically increasing.
 145          */
 146         avl_for_each_element(&patterns, ev, avl) {
 147                 const char *key = ev->avl.key;
 148                 int cur_match_len;
 149                 bool full_match;
 150
 151                 full_match = strmatch_len(id, key, &cur_match_len);
 152                 if (cur_match_len < match_len)
 153                         break;
 154
 155                 match_len = cur_match_len;
 156
 157                 if (!full_match) {
 158                         if (!ev->partial)
 159                                 continue;
 160
 161                         if (match_len != strlen(key))
 162                                 continue;
 163                 }
 164
 165                 ubusd_send_event_msg(&ub, cl, ev->obj, id, fill_cb, cb_priv);
 166         }
 167
 168         if (ub)
 169                 ubus_msg_free(ub);
 170
 171         return 0;
 172 }
 173
 174 enum {
 175         EVMSG_ID,
 176         EVMSG_DATA,
 177         EVMSG_LAST,
 178 };
 179
 180 static struct blobmsg_policy ev_policy[] = {
 181         [EVMSG_ID] = { .name = "id", .type = BLOBMSG_TYPE_STRING },
 182         [EVMSG_DATA] = { .name = "data", .type = BLOBMSG_TYPE_TABLE },
 183 };
 184
 185 static struct ubus_msg_buf *
 186 ubusd_create_event_from_msg(void *priv, const char *id)
 187 {
 188         struct blob_attr *msg = priv;
 189
 190         blob_buf_init(&b, 0);
 191         blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
 192         blob_put_string(&b, UBUS_ATTR_METHOD, id);
 193         blob_put(&b, UBUS_ATTR_DATA, blobmsg_data(msg), blobmsg_data_len(msg));
 194
 195         return ubus_msg_new(b.head, blob_raw_len(b.head), true);
 196 }
 197
 198 static int ubusd_forward_event(struct ubus_client *cl, struct blob_attr *msg)
 199 {
 200         struct blob_attr *data;
 201         struct blob_attr *attr[EVMSG_LAST];
 202         const char *id;
 203
 204         blobmsg_parse(ev_policy, EVMSG_LAST, attr, blob_data(msg), blob_len(msg));
 205         if (!attr[EVMSG_ID] || !attr[EVMSG_DATA])
 206                 return UBUS_STATUS_INVALID_ARGUMENT;
 207
 208         id = blobmsg_data(attr[EVMSG_ID]);
 209         data = attr[EVMSG_DATA];
 210
 211         if (!strncmp(id, "ubus.", 5))
 212                 return UBUS_STATUS_PERMISSION_DENIED;
 213
 214         return ubusd_send_event(cl, id, ubusd_create_event_from_msg, data);
 215 }
 216
 217 static int ubusd_event_recv(struct ubus_client *cl, const char *method, struct blob_attr *msg)
 218 {
 219         if (!strcmp(method, "register"))
 220                 return ubusd_alloc_event_pattern(cl, msg);
 221
 222         if (!strcmp(method, "send"))
 223                 return ubusd_forward_event(cl, msg);
 224
 225         return UBUS_STATUS_INVALID_COMMAND;
 226 }
 227
 228 static struct ubus_msg_buf *
 229 ubusd_create_object_event_msg(void *priv, const char *id)
 230 {
 231         struct ubus_object *obj = priv;
 232         void *s;
 233
 234         blob_buf_init(&b, 0);
 235         blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
 236         blob_put_string(&b, UBUS_ATTR_METHOD, id);
 237         s = blob_nest_start(&b, UBUS_ATTR_DATA);
 238         blobmsg_add_u32(&b, "id", obj->id.id);
 239         blobmsg_add_string(&b, "path", obj->path.key);
 240         blob_nest_end(&b, s);
 241
 242         return ubus_msg_new(b.head, blob_raw_len(b.head), true);
 243 }
 244
 245 void ubusd_send_obj_event(struct ubus_object *obj, bool add)
 246 {
 247         const char *id = add ? "ubus.object.add" : "ubus.object.remove";
 248
 249         ubusd_send_event(NULL, id, ubusd_create_object_event_msg, obj);
 250 }
 251
 252 void ubusd_event_init(void)
 253 {
 254         ubus_init_string_tree(&patterns, true);
 255         event_obj = ubusd_create_object_internal(NULL, UBUS_SYSTEM_OBJECT_EVENT);
 256         event_obj->recv_msg = ubusd_event_recv;
 257 }
 258