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, *name;
  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         name = (char *) (ev + 1);
  86         strcpy(name, pattern);
  87         ev->avl.key = name;
  88         avl_insert(&patterns, &ev->avl);
  89
  90         return 0;
  91 }
  92
  93 typedef struct ubus_msg_buf *(*event_fill_cb)(void *priv, const char *id);
  94
  95 static void ubusd_send_event_msg(struct ubus_msg_buf **ub, struct ubus_client *cl,
  96                                  struct ubus_object *obj, const char *id,
  97                                  event_fill_cb fill_cb, void *cb_priv)
  98 {
  99         uint32_t *objid_ptr;
 100
 101         /* do not loop back events */
 102         if (obj->client == cl)
 103             return;
 104
 105         /* do not send duplicate events */
 106         if (obj->event_seen == obj_event_seq)
 107                 return;
 108
 109         obj->event_seen = obj_event_seq;
 110
 111         if (!*ub) {
 112                 *ub = fill_cb(cb_priv, id);
 113                 (*ub)->hdr.type = UBUS_MSG_INVOKE;
 114                 (*ub)->hdr.peer = 0;
 115         }
 116
 117         objid_ptr = blob_data(blob_data((*ub)->data));
 118         *objid_ptr = htonl(obj->id.id);
 119
 120         (*ub)->hdr.seq = ++event_seq;
 121         ubus_msg_send(obj->client, *ub, false);
 122 }
 123
 124 bool strmatch_len(const char *s1, const char *s2, int *len)
 125 {
 126         for (*len = 0; s1[*len] == s2[*len]; (*len)++)
 127                 if (!s1[*len])
 128                         return true;
 129
 130         return false;
 131 }
 132
 133 static int ubusd_send_event(struct ubus_client *cl, const char *id,
 134                             event_fill_cb fill_cb, void *cb_priv)
 135 {
 136         struct ubus_msg_buf *ub = NULL;
 137         struct event_source *ev;
 138         int match_len = 0;
 139
 140         obj_event_seq++;
 141
 142         /*
 143          * Since this tree is sorted alphabetically, we can only expect to find
 144          * matching entries as long as the number of matching characters
 145          * between the pattern string and our string is monotonically increasing.
 146          */
 147         avl_for_each_element(&patterns, ev, avl) {
 148                 const char *key = ev->avl.key;
 149                 int cur_match_len;
 150                 bool full_match;
 151
 152                 full_match = strmatch_len(id, key, &cur_match_len);
 153                 if (cur_match_len < match_len)
 154                         break;
 155
 156                 match_len = cur_match_len;
 157
 158                 if (!full_match) {
 159                         if (!ev->partial)
 160                                 continue;
 161
 162                         if (match_len != strlen(key))
 163                                 continue;
 164                 }
 165
 166                 ubusd_send_event_msg(&ub, cl, ev->obj, id, fill_cb, cb_priv);
 167         }
 168
 169         if (ub)
 170                 ubus_msg_free(ub);
 171
 172         return 0;
 173 }
 174
 175 enum {
 176         EVMSG_ID,
 177         EVMSG_DATA,
 178         EVMSG_LAST,
 179 };
 180
 181 static struct blobmsg_policy ev_policy[] = {
 182         [EVMSG_ID] = { .name = "id", .type = BLOBMSG_TYPE_STRING },
 183         [EVMSG_DATA] = { .name = "data", .type = BLOBMSG_TYPE_TABLE },
 184 };
 185
 186 static struct ubus_msg_buf *
 187 ubusd_create_event_from_msg(void *priv, const char *id)
 188 {
 189         struct blob_attr *msg = priv;
 190
 191         blob_buf_init(&b, 0);
 192         blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
 193         blob_put_string(&b, UBUS_ATTR_METHOD, id);
 194         blob_put(&b, UBUS_ATTR_DATA, blobmsg_data(msg), blobmsg_data_len(msg));
 195
 196         return ubus_msg_new(b.head, blob_raw_len(b.head), true);
 197 }
 198
 199 static int ubusd_forward_event(struct ubus_client *cl, struct blob_attr *msg)
 200 {
 201         struct blob_attr *data;
 202         struct blob_attr *attr[EVMSG_LAST];
 203         const char *id;
 204
 205         blobmsg_parse(ev_policy, EVMSG_LAST, attr, blob_data(msg), blob_len(msg));
 206         if (!attr[EVMSG_ID] || !attr[EVMSG_DATA])
 207                 return UBUS_STATUS_INVALID_ARGUMENT;
 208
 209         id = blobmsg_data(attr[EVMSG_ID]);
 210         data = attr[EVMSG_DATA];
 211
 212         if (!strncmp(id, "ubus.", 5))
 213                 return UBUS_STATUS_PERMISSION_DENIED;
 214
 215         return ubusd_send_event(cl, id, ubusd_create_event_from_msg, data);
 216 }
 217
 218 static int ubusd_event_recv(struct ubus_client *cl, const char *method, struct blob_attr *msg)
 219 {
 220         if (!strcmp(method, "register"))
 221                 return ubusd_alloc_event_pattern(cl, msg);
 222
 223         if (!strcmp(method, "send"))
 224                 return ubusd_forward_event(cl, msg);
 225
 226         return UBUS_STATUS_INVALID_COMMAND;
 227 }
 228
 229 static struct ubus_msg_buf *
 230 ubusd_create_object_event_msg(void *priv, const char *id)
 231 {
 232         struct ubus_object *obj = priv;
 233         void *s;
 234
 235         blob_buf_init(&b, 0);
 236         blob_put_int32(&b, UBUS_ATTR_OBJID, 0);
 237         blob_put_string(&b, UBUS_ATTR_METHOD, id);
 238         s = blob_nest_start(&b, UBUS_ATTR_DATA);
 239         blobmsg_add_u32(&b, "id", obj->id.id);
 240         blobmsg_add_string(&b, "path", obj->path.key);
 241         blob_nest_end(&b, s);
 242
 243         return ubus_msg_new(b.head, blob_raw_len(b.head), true);
 244 }
 245
 246 void ubusd_send_obj_event(struct ubus_object *obj, bool add)
 247 {
 248         const char *id = add ? "ubus.object.add" : "ubus.object.remove";
 249
 250         ubusd_send_event(NULL, id, ubusd_create_object_event_msg, obj);
 251 }
 252
 253 void ubusd_event_init(void)
 254 {
 255         ubus_init_string_tree(&patterns, true);
 256         event_obj = ubusd_create_object_internal(NULL, UBUS_SYSTEM_OBJECT_EVENT);
 257         event_obj->recv_msg = ubusd_event_recv;
 258 }
 259