ubusd_event.c

   1 #include <arpa/inet.h>
   2 #include "ubusd.h"
   3
   4 static struct avl_tree patterns;
   5 static LIST_HEAD(catch_all);
   6 static struct ubus_object *event_obj;
   7 static int event_seq = 0;
   8 static int obj_event_seq = 0;
   9
  10 enum evs_type {
  11         EVS_PATTERN,
  12         EVS_CATCHALL
  13 };
  14
  15 struct event_source {
  16         struct list_head list;
  17         struct ubus_object *obj;
  18         enum evs_type type;
  19         union {
  20                 struct {
  21                         struct avl_node avl;
  22                         bool partial;
  23                 } pattern;
  24                 struct {
  25                         struct list_head list;
  26                 } catchall;
  27         };
  28 };
  29
  30 static void ubusd_delete_event_source(struct event_source *evs)
  31 {
  32         list_del(&evs->list);
  33         switch (evs->type) {
  34         case EVS_PATTERN:
  35                 avl_delete(&patterns, &evs->pattern.avl);
  36                 break;
  37         case EVS_CATCHALL:
  38                 list_del(&evs->catchall.list);
  39                 break;
  40         }
  41         free(evs);
  42 }
  43
  44 void ubusd_event_cleanup_object(struct ubus_object *obj)
  45 {
  46         struct event_source *ev;
  47
  48         while (!list_empty(&obj->events)) {
  49                 ev = list_first_entry(&obj->events, struct event_source, list);
  50                 ubusd_delete_event_source(ev);
  51         }
  52 }
  53
  54 enum {
  55         EVREG_PATTERN,
  56         EVREG_OBJECT,
  57         EVREG_LAST,
  58 };
  59
  60 static struct blobmsg_policy evr_policy[] = {
  61         [EVREG_PATTERN] = { .name = "pattern", .type = BLOBMSG_TYPE_STRING },
  62         [EVREG_OBJECT] = { .name = "object", .type = BLOBMSG_TYPE_INT32 },
  63 };
  64
  65
  66 static struct event_source *ubusd_alloc_event_source(struct ubus_object *obj, enum evs_type type, int datalen)
  67 {
  68         struct event_source *evs;
  69
  70         evs = calloc(1, sizeof(*evs) + datalen);
  71         list_add(&evs->list, &obj->events);
  72         evs->obj = obj;
  73         evs->type = type;
  74         return evs;
  75 }
  76
  77 static int ubusd_alloc_catchall(struct ubus_object *obj)
  78 {
  79         struct event_source *evs;
  80
  81         evs = ubusd_alloc_event_source(obj, EVS_CATCHALL, 0);
  82         list_add(&evs->catchall.list, &catch_all);
  83
  84         return 0;
  85 }
  86
  87 static int ubusd_alloc_event_pattern(struct ubus_client *cl, struct blob_attr *msg)
  88 {
  89         struct event_source *ev;
  90         struct ubus_object *obj;
  91         struct blob_attr *attr[EVREG_LAST];
  92         char *pattern;
  93         uint32_t id;
  94         bool partial = false;
  95         int len;
  96
  97         blobmsg_parse(evr_policy, EVREG_LAST, attr, blob_data(msg), blob_len(msg));
  98         if (!attr[EVREG_OBJECT])
  99                 return UBUS_STATUS_INVALID_ARGUMENT;
 100
 101         id = blobmsg_get_u32(attr[EVREG_OBJECT]);
 102         if (id < UBUS_SYSTEM_OBJECT_MAX)
 103                 return UBUS_STATUS_PERMISSION_DENIED;
 104
 105         obj = ubusd_find_object(id);
 106         if (!obj)
 107                 return UBUS_STATUS_NOT_FOUND;
 108
 109         if (obj->client != cl)
 110                 return UBUS_STATUS_PERMISSION_DENIED;
 111
 112         if (!attr[EVREG_PATTERN])
 113                 return ubusd_alloc_catchall(obj);
 114
 115         pattern = blobmsg_data(attr[EVREG_PATTERN]);
 116
 117         len = strlen(pattern);
 118         if (pattern[len - 1] == '*') {
 119                 partial = true;
 120                 pattern[len - 1] = 0;
 121                 len--;
 122         }
 123
 124         ev = ubusd_alloc_event_source(obj, EVS_PATTERN, len + 1);
 125         ev->pattern.partial = partial;
 126         ev->pattern.avl.key = (void *) (ev + 1);
 127         strcpy(ev->pattern.avl.key, pattern);
 128         avl_insert(&patterns, &ev->pattern.avl);
 129
 130         return 0;
 131 }
 132
 133 static void ubusd_send_event_msg(struct ubus_msg_buf **ub, struct ubus_client *cl,
 134                                  struct ubus_object *obj, const char *id,
 135                                  struct blob_attr *msg)
 136 {
 137         uint32_t *objid_ptr;
 138
 139         /* do not loop back events */
 140         if (obj->client == cl)
 141             return;
 142
 143         /* do not send duplicate events */
 144         if (obj->event_seen == obj_event_seq)
 145                 return;
 146
 147         obj->event_seen = obj_event_seq;
 148
 149         if (*ub) {
 150                 objid_ptr = blob_data(blob_data((*ub)->data));
 151                 *objid_ptr = htonl(obj->id.id);
 152         } else {
 153                 blob_buf_init(&b, 0);
 154                 blob_put_int32(&b, UBUS_ATTR_OBJID, obj->id.id);
 155                 blob_put_string(&b, UBUS_ATTR_METHOD, id);
 156                 blob_put(&b, UBUS_ATTR_DATA, blobmsg_data(msg), blobmsg_data_len(msg));
 157
 158                 *ub = ubus_msg_new(b.head, blob_raw_len(b.head), true);
 159
 160                 (*ub)->hdr.type = UBUS_MSG_INVOKE;
 161                 (*ub)->hdr.peer = 0;
 162         }
 163         (*ub)->hdr.seq = ++event_seq;
 164         ubus_msg_send(obj->client, *ub, false);
 165 }
 166
 167 bool strmatch_len(const char *s1, const char *s2, int *len)
 168 {
 169         for (*len = 0; s1[*len] == s2[*len]; (*len)++)
 170                 if (!s1[*len])
 171                         return true;
 172
 173         return false;
 174 }
 175
 176 static int ubusd_send_event(struct ubus_client *cl, const char *id,
 177                             struct blob_attr *data, struct ubus_msg_buf *ub)
 178 {
 179         struct event_source *ev;
 180         int match_len = 0;
 181
 182         list_for_each_entry(ev, &catch_all, catchall.list)
 183                 ubusd_send_event_msg(&ub, cl, ev->obj, id, data);
 184
 185         obj_event_seq++;
 186
 187         /*
 188          * Since this tree is sorted alphabetically, we can only expect to find
 189          * matching entries as long as the number of matching characters
 190          * between the pattern string and our string is monotonically increasing.
 191          */
 192         avl_for_each_element(&patterns, ev, pattern.avl) {
 193                 const char *key = ev->pattern.avl.key;
 194                 int cur_match_len;
 195                 bool full_match;
 196
 197                 full_match = strmatch_len(id, key, &cur_match_len);
 198                 if (cur_match_len < match_len)
 199                         break;
 200
 201                 match_len = cur_match_len;
 202
 203                 if (!full_match) {
 204                         if (!ev->pattern.partial)
 205                                 continue;
 206
 207                         if (match_len != strlen(key))
 208                                 continue;
 209                 }
 210
 211                 ubusd_send_event_msg(&ub, cl, ev->obj, id, data);
 212         }
 213
 214         if (ub)
 215                 ubus_msg_free(ub);
 216
 217         return 0;
 218 }
 219
 220 enum {
 221         EVMSG_ID,
 222         EVMSG_DATA,
 223         EVMSG_LAST,
 224 };
 225
 226 static struct blobmsg_policy ev_policy[] = {
 227         [EVMSG_ID] = { .name = "id", .type = BLOBMSG_TYPE_STRING },
 228         [EVMSG_DATA] = { .name = "data", .type = BLOBMSG_TYPE_TABLE },
 229 };
 230
 231 static int ubusd_forward_event(struct ubus_client *cl, struct blob_attr *msg)
 232 {
 233         struct blob_attr *data;
 234         struct blob_attr *attr[EVMSG_LAST];
 235         const char *id;
 236
 237         blobmsg_parse(ev_policy, EVMSG_LAST, attr, blob_data(msg), blob_len(msg));
 238         if (!attr[EVMSG_ID] || !attr[EVMSG_DATA])
 239                 return UBUS_STATUS_INVALID_ARGUMENT;
 240
 241         id = blobmsg_data(attr[EVMSG_ID]);
 242         data = attr[EVMSG_DATA];
 243
 244         if (!strncmp(id, "ubus.", 5))
 245                 return UBUS_STATUS_PERMISSION_DENIED;
 246
 247         return ubusd_send_event(cl, id, data, NULL);
 248 }
 249
 250 static int ubusd_event_recv(struct ubus_client *cl, const char *method, struct blob_attr *msg)
 251 {
 252         if (!strcmp(method, "register"))
 253                 return ubusd_alloc_event_pattern(cl, msg);
 254
 255         if (!strcmp(method, "send"))
 256                 return ubusd_forward_event(cl, msg);
 257
 258         return UBUS_STATUS_INVALID_COMMAND;
 259 }
 260
 261 void ubusd_event_init(void)
 262 {
 263         ubus_init_string_tree(&patterns, true);
 264         event_obj = ubusd_create_object_internal(NULL, UBUS_SYSTEM_OBJECT_EVENT);
 265         event_obj->recv_msg = ubusd_event_recv;
 266 }
 267