libubus.c

   1 #include <sys/types.h>
   2 #include <sys/uio.h>
   3 #include <sys/socket.h>
   4 #include <unistd.h>
   5
   6 #include <libubox/blob.h>
   7 #include <libubox/blobmsg.h>
   8 #include <libubox/usock.h>
   9
  10 #include "libubus.h"
  11 #include "ubusmsg.h"
  12
  13 #define DEBUG 1
  14
  15 #ifdef DEBUG
  16 #define DPRINTF(_format, ...) fprintf(stderr, "ubus: " _format, ## __VA_ARGS__)
  17 #else
  18 #define DPRINTF(...) do {} while(0)
  19 #endif
  20
  21 #define STATIC_IOV(_var) { .iov_base = (char *) &(_var), .iov_len = sizeof(_var) }
  22
  23 const char *__ubus_strerror[__UBUS_STATUS_LAST] = {
  24         [UBUS_STATUS_OK] = "Success",
  25         [UBUS_STATUS_INVALID_COMMAND] = "Invalid command",
  26         [UBUS_STATUS_INVALID_ARGUMENT] = "Invalid argument",
  27         [UBUS_STATUS_NOT_FOUND] = "Not found",
  28         [UBUS_STATUS_NO_DATA] = "No response",
  29 };
  30
  31 static struct blob_buf b;
  32
  33 static const struct blob_attr_info ubus_policy[UBUS_ATTR_MAX] = {
  34         [UBUS_ATTR_STATUS] = { .type = BLOB_ATTR_INT32 },
  35         [UBUS_ATTR_OBJID] = { .type = BLOB_ATTR_INT32 },
  36         [UBUS_ATTR_OBJPATH] = { .type = BLOB_ATTR_STRING },
  37 };
  38 static struct blob_attr *attrbuf[UBUS_ATTR_MAX];
  39
  40 struct ubus_pending_data {
  41         struct list_head list;
  42         int type;
  43         struct blob_attr data[];
  44 };
  45
  46 struct blob_attr **ubus_parse_msg(struct blob_attr *msg)
  47 {
  48         blob_parse(msg, attrbuf, ubus_policy, UBUS_ATTR_MAX);
  49         return attrbuf;
  50 }
  51
  52 const char *ubus_strerror(int error)
  53 {
  54         static char err[32];
  55
  56         if (error < 0 || error >= __UBUS_STATUS_LAST)
  57                 goto out;
  58
  59         if (!__ubus_strerror[error])
  60                 goto out;
  61
  62         return __ubus_strerror[error];
  63
  64 out:
  65         sprintf(err, "Unknown error: %d", error);
  66         return err;
  67 }
  68
  69 static int ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
  70                          struct blob_attr *msg, int cmd, uint32_t peer)
  71 {
  72         struct ubus_msghdr hdr;
  73         struct iovec iov[2] = {
  74                 STATIC_IOV(hdr)
  75         };
  76
  77         hdr.version = 0;
  78         hdr.type = cmd;
  79         hdr.seq = seq;
  80         hdr.peer = peer;
  81
  82         if (!msg) {
  83                 blob_buf_init(&b, 0);
  84                 msg = b.head;
  85         }
  86
  87         iov[1].iov_base = (char *) msg;
  88         iov[1].iov_len = blob_raw_len(msg);
  89
  90         return writev(ctx->sock.fd, iov, 2);
  91 }
  92
  93 int ubus_start_request(struct ubus_context *ctx, struct ubus_request *req,
  94                        struct blob_attr *msg, int cmd, uint32_t peer)
  95 {
  96         memset(req, 0, sizeof(*req));
  97
  98         INIT_LIST_HEAD(&req->list);
  99         INIT_LIST_HEAD(&req->pending);
 100         req->peer = peer;
 101         req->seq = ++ctx->request_seq;
 102         return ubus_send_msg(ctx, req->seq, msg, cmd, peer);
 103 }
 104
 105 static bool recv_retry(int fd, struct iovec *iov, bool wait)
 106 {
 107         int bytes;
 108
 109         while (iov->iov_len > 0) {
 110                 bytes = read(fd, iov->iov_base, iov->iov_len);
 111                 if (bytes < 0) {
 112                         bytes = 0;
 113                         if (errno == EINTR)
 114                                 continue;
 115
 116                         if (errno != EAGAIN) {
 117                                 perror("read");
 118                                 return false;
 119                         }
 120                 }
 121                 if (!wait && !bytes)
 122                         return false;
 123
 124                 wait = true;
 125                 iov->iov_len -= bytes;
 126                 iov->iov_base += bytes;
 127         }
 128
 129         return true;
 130 }
 131
 132 static bool ubus_validate_hdr(struct ubus_msghdr *hdr)
 133 {
 134         if (hdr->version != 0)
 135                 return false;
 136
 137         if (blob_raw_len(hdr->data) < sizeof(*hdr->data))
 138                 return false;
 139
 140         if (blob_raw_len(hdr->data) + sizeof(*hdr) > UBUS_MAX_MSGLEN)
 141                 return false;
 142
 143         return true;
 144 }
 145
 146 static bool get_next_msg(struct ubus_context *ctx, bool wait)
 147 {
 148         struct iovec iov = STATIC_IOV(ctx->msgbuf.hdr);
 149
 150         /* receive header + start attribute */
 151         iov.iov_len += sizeof(struct blob_attr);
 152         if (!recv_retry(ctx->sock.fd, &iov, wait))
 153                 return false;
 154
 155         iov.iov_len = blob_len(ctx->msgbuf.hdr.data);
 156         if (iov.iov_len > 0 && !recv_retry(ctx->sock.fd, &iov, true))
 157                 return false;
 158
 159         return ubus_validate_hdr(&ctx->msgbuf.hdr);
 160 }
 161
 162 static bool ubus_get_status(struct ubus_msghdr *hdr, int *ret)
 163 {
 164         ubus_parse_msg(hdr->data);
 165
 166         if (!attrbuf[UBUS_ATTR_STATUS])
 167                 return false;
 168
 169         *ret = blob_get_int32(attrbuf[UBUS_ATTR_STATUS]);
 170         return true;
 171 }
 172
 173 static void ubus_process_req_data(struct ubus_request *req)
 174 {
 175         struct ubus_pending_data *data;
 176
 177         while (!list_empty(&req->pending)) {
 178                 data = list_first_entry(&req->pending,
 179                         struct ubus_pending_data, list);
 180                 list_del(&data->list);
 181                 req->data_cb(req, data->type, data->data);
 182                 free(data);
 183         }
 184 }
 185
 186 static void ubus_req_complete_cb(struct ubus_request *req)
 187 {
 188         ubus_complete_handler_t cb = req->complete_cb;
 189
 190         if (!cb)
 191                 return;
 192
 193         req->complete_cb = NULL;
 194         cb(req, req->status_code);
 195 }
 196
 197 static int ubus_process_req_status(struct ubus_request *req, struct ubus_msghdr *hdr)
 198 {
 199         int ret = UBUS_STATUS_INVALID_ARGUMENT;
 200
 201         if (!list_empty(&req->list))
 202                 list_del(&req->list);
 203
 204         ubus_get_status(hdr, &ret);
 205         req->peer = hdr->peer;
 206         req->status_msg = true;
 207         req->status_code = ret;
 208         if (!req->blocked)
 209                 ubus_req_complete_cb(req);
 210
 211         return ret;
 212 }
 213
 214 static void ubus_req_data(struct ubus_request *req, struct ubus_msghdr *hdr)
 215 {
 216         struct ubus_pending_data *data;
 217         int len;
 218
 219         if (!req->blocked) {
 220                 req->blocked = true;
 221                 req->data_cb(req, hdr->type, hdr->data);
 222                 ubus_process_req_data(req);
 223                 req->blocked = false;
 224
 225                 if (req->status_msg)
 226                         ubus_req_complete_cb(req);
 227
 228                 return;
 229         }
 230
 231         len = blob_raw_len(hdr->data);
 232         data = calloc(1, sizeof(*data) + len);
 233         if (!data)
 234                 return;
 235
 236         data->type = hdr->type;
 237         memcpy(data->data, hdr->data, len);
 238         list_add(&data->list, &req->pending);
 239 }
 240
 241 static struct ubus_request *ubus_find_request(struct ubus_context *ctx, uint32_t seq, uint32_t peer)
 242 {
 243         struct ubus_request *req;
 244
 245         list_for_each_entry(req, &ctx->requests, list) {
 246                 if (seq != req->seq || peer != req->peer)
 247                         continue;
 248
 249                 return req;
 250         }
 251         return NULL;
 252 }
 253
 254 static void ubus_process_invoke(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 255 {
 256         uint32_t objid = 0;
 257         int ret = 0;
 258
 259         ubus_parse_msg(hdr->data);
 260
 261         if (attrbuf[UBUS_ATTR_OBJID])
 262                 objid = blob_get_int32(attrbuf[UBUS_ATTR_OBJID]);
 263
 264         blob_buf_init(&b, 0);
 265         blob_put_int32(&b, UBUS_ATTR_STATUS, ret);
 266         blob_put_int32(&b, UBUS_ATTR_OBJID, objid);
 267         ubus_send_msg(ctx, hdr->seq, b.head, UBUS_MSG_STATUS, hdr->peer);
 268 }
 269
 270 static void ubus_process_msg(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 271 {
 272         struct ubus_request *req;
 273
 274         switch(hdr->type) {
 275         case UBUS_MSG_STATUS:
 276                 req = ubus_find_request(ctx, hdr->seq, hdr->peer);
 277                 if (!req)
 278                         break;
 279
 280                 ubus_process_req_status(req, hdr);
 281                 break;
 282
 283         case UBUS_MSG_DATA:
 284                 req = ubus_find_request(ctx, hdr->seq, hdr->peer);
 285                 if (req && req->data_cb)
 286                         ubus_req_data(req, hdr);
 287                 break;
 288
 289         case UBUS_MSG_INVOKE:
 290                 ubus_process_invoke(ctx, hdr);
 291                 break;
 292         default:
 293                 DPRINTF("unknown message type: %d\n", hdr->type);
 294                 break;
 295         }
 296 }
 297
 298 void ubus_abort_request(struct ubus_context *ctx, struct ubus_request *req)
 299 {
 300         if (!list_empty(&req->list))
 301                 return;
 302
 303         list_del(&req->list);
 304 }
 305
 306 void ubus_complete_request_async(struct ubus_context *ctx, struct ubus_request *req)
 307 {
 308         if (!list_empty(&req->list))
 309                 return;
 310
 311         list_add(&req->list, &ctx->requests);
 312 }
 313
 314 static void ubus_handle_data(struct uloop_fd *u, unsigned int events)
 315 {
 316         struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
 317         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 318
 319         while (get_next_msg(ctx, false))
 320                 ubus_process_msg(ctx, hdr);
 321 }
 322
 323 int ubus_complete_request(struct ubus_context *ctx, struct ubus_request *req)
 324 {
 325         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 326
 327         if (!list_empty(&req->list))
 328                 list_del(&req->list);
 329
 330         while (1) {
 331                 if (req->status_msg)
 332                         return req->status_code;
 333
 334                 if (!get_next_msg(ctx, true))
 335                         return UBUS_STATUS_NO_DATA;
 336
 337                 if (hdr->seq != req->seq || hdr->peer != req->peer)
 338                         goto skip;
 339
 340                 switch(hdr->type) {
 341                 case UBUS_MSG_STATUS:
 342                         return ubus_process_req_status(req, hdr);
 343                 case UBUS_MSG_DATA:
 344                         if (req->data_cb)
 345                                 ubus_req_data(req, hdr);
 346                         continue;
 347                 default:
 348                         goto skip;
 349                 }
 350
 351 skip:
 352                 ubus_process_msg(ctx, hdr);
 353         }
 354 }
 355
 356 void ubus_invoke_async(struct ubus_context *ctx, uint32_t obj, const char *method,
 357                        struct blob_attr *msg, struct ubus_request *req)
 358 {
 359         blob_buf_init(&b, 0);
 360         blob_put_int32(&b, UBUS_ATTR_OBJID, obj);
 361         blob_put_string(&b, UBUS_ATTR_METHOD, method);
 362         blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
 363
 364         ubus_start_request(ctx, req, b.head, UBUS_MSG_INVOKE, obj);
 365 }
 366
 367 int ubus_invoke(struct ubus_context *ctx, uint32_t obj, const char *method,
 368                 struct blob_attr *msg, ubus_data_handler_t cb, void *priv)
 369 {
 370         struct ubus_request req;
 371
 372         ubus_invoke_async(ctx, obj, method, msg, &req);
 373         req.data_cb = cb;
 374         req.priv = priv;
 375         return ubus_complete_request(ctx, &req);
 376 }
 377
 378 static void ubus_publish_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 379 {
 380         struct ubus_object *obj = req->priv;
 381
 382         ubus_parse_msg(msg);
 383
 384         if (!attrbuf[UBUS_ATTR_OBJID])
 385                 return;
 386
 387         obj->id = blob_get_int32(attrbuf[UBUS_ATTR_OBJID]);
 388
 389         if (attrbuf[UBUS_ATTR_OBJTYPE])
 390                 obj->type->id = blob_get_int32(attrbuf[UBUS_ATTR_OBJTYPE]);
 391 }
 392
 393 static bool ubus_push_table_data(const struct ubus_signature **sig, int *rem, bool array)
 394 {
 395         const struct ubus_signature *cur;
 396         bool nest_type;
 397         void *nest;
 398
 399         while (rem) {
 400                 cur = (*sig)++;
 401                 (*rem)--;
 402                 switch(cur->type) {
 403                 case UBUS_SIGNATURE_END:
 404                         return !array;
 405                 case BLOBMSG_TYPE_INT32:
 406                 case BLOBMSG_TYPE_STRING:
 407                         blobmsg_add_u32(&b, cur->name, cur->type);
 408                         break;
 409                 case BLOBMSG_TYPE_TABLE:
 410                 case BLOBMSG_TYPE_ARRAY:
 411                         nest_type = cur->type == BLOBMSG_TYPE_ARRAY;
 412                         nest = blobmsg_open_nested(&b, cur->name, nest_type);
 413                         if (!ubus_push_table_data(sig, rem, nest_type))
 414                                 return false;
 415                         blobmsg_close_table(&b, nest);
 416                         break;
 417                 default:
 418                         return false;
 419                 }
 420                 if (array)
 421                         return true;
 422         }
 423         return false;
 424 }
 425
 426 static bool ubus_push_object_type(struct ubus_object_type *type)
 427 {
 428         void *s, *m;
 429         int rem = type->n_signature;
 430         const struct ubus_signature *sig = type->signature;
 431
 432         s = blob_nest_start(&b, UBUS_ATTR_SIGNATURE);
 433         while (rem) {
 434                 if (sig->type != UBUS_SIGNATURE_METHOD)
 435                         return false;
 436
 437                 m = blobmsg_open_table(&b, sig->name);
 438
 439                 sig++;
 440                 rem--;
 441                 if (!ubus_push_table_data(&sig, &rem, false))
 442                         return false;
 443
 444                 blobmsg_close_table(&b, m);
 445         }
 446         blob_nest_end(&b, s);
 447
 448         return true;
 449 }
 450
 451 int ubus_publish(struct ubus_context *ctx, struct ubus_object *obj)
 452 {
 453         struct ubus_request req;
 454         int ret;
 455
 456         if (obj->id || !obj->name || !obj->type)
 457                 return UBUS_STATUS_INVALID_ARGUMENT;
 458
 459         blob_buf_init(&b, 0);
 460         blob_put_string(&b, UBUS_ATTR_OBJPATH, obj->name);
 461         if (obj->parent)
 462                 blob_put_int32(&b, UBUS_ATTR_OBJID, obj->parent->id);
 463
 464         if (obj->type->id)
 465                 blob_put_int32(&b, UBUS_ATTR_OBJTYPE, obj->type->id);
 466         else if (!ubus_push_object_type(obj->type))
 467                 return UBUS_STATUS_INVALID_ARGUMENT;
 468
 469         ubus_start_request(ctx, &req, b.head, UBUS_MSG_PUBLISH, 0);
 470         req.data_cb = ubus_publish_cb;
 471         req.priv = obj;
 472         ret = ubus_complete_request(ctx, &req);
 473         if (ret)
 474                 return ret;
 475
 476         if (!obj->id)
 477                 return UBUS_STATUS_NO_DATA;
 478
 479         return 0;
 480 }
 481
 482 struct ubus_context *ubus_connect(const char *path)
 483 {
 484         struct ubus_context *ctx;
 485         struct {
 486                 struct ubus_msghdr hdr;
 487                 struct blob_attr data;
 488         } hdr;
 489         struct blob_attr *buf;
 490
 491         if (!path)
 492                 path = UBUS_UNIX_SOCKET;
 493
 494         ctx = calloc(1, sizeof(*ctx));
 495         if (!ctx)
 496                 goto error;
 497
 498         ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
 499         if (ctx->sock.fd < 0) {
 500                 DPRINTF("Failed to connect to server\n");
 501                 goto error_free;
 502         }
 503         ctx->sock.cb = ubus_handle_data;
 504
 505         if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr)) {
 506                 DPRINTF("Failed to read initial message data\n");
 507                 goto error_close;
 508         }
 509
 510         if (!ubus_validate_hdr(&hdr.hdr)) {
 511                 DPRINTF("Failed to validate initial message header\n");
 512                 goto error_close;
 513         }
 514
 515         if (hdr.hdr.type != UBUS_MSG_HELLO) {
 516                 DPRINTF("Unexpected initial message\n");
 517                 goto error_close;
 518         }
 519
 520         buf = calloc(1, blob_raw_len(&hdr.data));
 521         if (!buf)
 522                 goto error_close;
 523
 524         memcpy(buf, &hdr.data, sizeof(hdr.data));
 525         if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf)) {
 526                 DPRINTF("Failed to retrieve initial message data\n");
 527                 goto error_free_buf;
 528         }
 529
 530         ctx->local_id = hdr.hdr.peer;
 531         INIT_LIST_HEAD(&ctx->requests);
 532         free(buf);
 533
 534         if (!ctx->local_id) {
 535                 DPRINTF("Failed to get local peer id\n");
 536                 goto error_close;
 537         }
 538
 539         return ctx;
 540
 541 error_free_buf:
 542         free(buf);
 543 error_close:
 544         close(ctx->sock.fd);
 545 error_free:
 546         free(ctx);
 547 error:
 548         return NULL;
 549 }
 550
 551 void ubus_free(struct ubus_context *ctx)
 552 {
 553         close(ctx->sock.fd);
 554         free(ctx);
 555 }