ubusd_event.c

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