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_METHOD_NOT_FOUND] = "Method not found",
  28         [UBUS_STATUS_NOT_FOUND] = "Not found",
  29         [UBUS_STATUS_NO_DATA] = "No response",
  30 };
  31
  32 static struct blob_buf b;
  33
  34 static const struct blob_attr_info ubus_policy[UBUS_ATTR_MAX] = {
  35         [UBUS_ATTR_STATUS] = { .type = BLOB_ATTR_INT32 },
  36         [UBUS_ATTR_OBJID] = { .type = BLOB_ATTR_INT32 },
  37         [UBUS_ATTR_OBJPATH] = { .type = BLOB_ATTR_STRING },
  38         [UBUS_ATTR_METHOD] = { .type = BLOB_ATTR_STRING },
  39 };
  40 static struct blob_attr *attrbuf[UBUS_ATTR_MAX];
  41
  42 struct ubus_pending_data {
  43         struct list_head list;
  44         int type;
  45         struct blob_attr data[];
  46 };
  47
  48 static int ubus_cmp_id(const void *k1, const void *k2, void *ptr)
  49 {
  50         const uint32_t *id1 = k1, *id2 = k2;
  51
  52         if (*id1 < *id2)
  53                 return -1;
  54         else
  55                 return *id1 > *id2;
  56 }
  57
  58 struct blob_attr **ubus_parse_msg(struct blob_attr *msg)
  59 {
  60         blob_parse(msg, attrbuf, ubus_policy, UBUS_ATTR_MAX);
  61         return attrbuf;
  62 }
  63
  64 const char *ubus_strerror(int error)
  65 {
  66         static char err[32];
  67
  68         if (error < 0 || error >= __UBUS_STATUS_LAST)
  69                 goto out;
  70
  71         if (!__ubus_strerror[error])
  72                 goto out;
  73
  74         return __ubus_strerror[error];
  75
  76 out:
  77         sprintf(err, "Unknown error: %d", error);
  78         return err;
  79 }
  80
  81 static int ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
  82                          struct blob_attr *msg, int cmd, uint32_t peer)
  83 {
  84         struct ubus_msghdr hdr;
  85         struct iovec iov[2] = {
  86                 STATIC_IOV(hdr)
  87         };
  88
  89         hdr.version = 0;
  90         hdr.type = cmd;
  91         hdr.seq = seq;
  92         hdr.peer = peer;
  93
  94         if (!msg) {
  95                 blob_buf_init(&b, 0);
  96                 msg = b.head;
  97         }
  98
  99         iov[1].iov_base = (char *) msg;
 100         iov[1].iov_len = blob_raw_len(msg);
 101
 102         return writev(ctx->sock.fd, iov, 2);
 103 }
 104
 105 int ubus_start_request(struct ubus_context *ctx, struct ubus_request *req,
 106                        struct blob_attr *msg, int cmd, uint32_t peer)
 107 {
 108         memset(req, 0, sizeof(*req));
 109
 110         INIT_LIST_HEAD(&req->list);
 111         INIT_LIST_HEAD(&req->pending);
 112         req->ctx = ctx;
 113         req->peer = peer;
 114         req->seq = ++ctx->request_seq;
 115         return ubus_send_msg(ctx, req->seq, msg, cmd, peer);
 116 }
 117
 118 static bool recv_retry(int fd, struct iovec *iov, bool wait)
 119 {
 120         int bytes;
 121
 122         while (iov->iov_len > 0) {
 123                 bytes = read(fd, iov->iov_base, iov->iov_len);
 124                 if (bytes < 0) {
 125                         bytes = 0;
 126                         if (errno == EINTR)
 127                                 continue;
 128
 129                         if (errno != EAGAIN) {
 130                                 perror("read");
 131                                 return false;
 132                         }
 133                 }
 134                 if (!wait && !bytes)
 135                         return false;
 136
 137                 wait = true;
 138                 iov->iov_len -= bytes;
 139                 iov->iov_base += bytes;
 140         }
 141
 142         return true;
 143 }
 144
 145 static bool ubus_validate_hdr(struct ubus_msghdr *hdr)
 146 {
 147         if (hdr->version != 0)
 148                 return false;
 149
 150         if (blob_raw_len(hdr->data) < sizeof(*hdr->data))
 151                 return false;
 152
 153         if (blob_raw_len(hdr->data) + sizeof(*hdr) > UBUS_MAX_MSGLEN)
 154                 return false;
 155
 156         return true;
 157 }
 158
 159 static bool get_next_msg(struct ubus_context *ctx, bool wait)
 160 {
 161         struct iovec iov = STATIC_IOV(ctx->msgbuf.hdr);
 162
 163         /* receive header + start attribute */
 164         iov.iov_len += sizeof(struct blob_attr);
 165         if (!recv_retry(ctx->sock.fd, &iov, wait))
 166                 return false;
 167
 168         iov.iov_len = blob_len(ctx->msgbuf.hdr.data);
 169         if (iov.iov_len > 0 && !recv_retry(ctx->sock.fd, &iov, true))
 170                 return false;
 171
 172         return ubus_validate_hdr(&ctx->msgbuf.hdr);
 173 }
 174
 175 static bool ubus_get_status(struct ubus_msghdr *hdr, int *ret)
 176 {
 177         ubus_parse_msg(hdr->data);
 178
 179         if (!attrbuf[UBUS_ATTR_STATUS])
 180                 return false;
 181
 182         *ret = blob_get_int32(attrbuf[UBUS_ATTR_STATUS]);
 183         return true;
 184 }
 185
 186 static void req_data_cb(struct ubus_request *req, int type, struct blob_attr *data)
 187 {
 188         struct blob_attr **attr;
 189
 190         if (req->raw_data_cb)
 191                 req->raw_data_cb(req, type, data);
 192
 193         if (!req->data_cb)
 194                 return;
 195
 196         attr = ubus_parse_msg(data);
 197         req->data_cb(req, type, attr[UBUS_ATTR_DATA]);
 198 }
 199
 200 static void ubus_process_req_data(struct ubus_request *req)
 201 {
 202         struct ubus_pending_data *data;
 203
 204         while (!list_empty(&req->pending)) {
 205                 data = list_first_entry(&req->pending,
 206                         struct ubus_pending_data, list);
 207                 list_del(&data->list);
 208                 if (!req->cancelled)
 209                         req_data_cb(req, data->type, data->data);
 210                 free(data);
 211         }
 212 }
 213
 214 static void ubus_req_complete_cb(struct ubus_request *req)
 215 {
 216         ubus_complete_handler_t cb = req->complete_cb;
 217
 218         if (!cb)
 219                 return;
 220
 221         req->complete_cb = NULL;
 222         cb(req, req->status_code);
 223 }
 224
 225 static int ubus_process_req_status(struct ubus_request *req, struct ubus_msghdr *hdr)
 226 {
 227         int ret = UBUS_STATUS_INVALID_ARGUMENT;
 228
 229         if (!list_empty(&req->list))
 230                 list_del(&req->list);
 231
 232         ubus_get_status(hdr, &ret);
 233         req->peer = hdr->peer;
 234         req->status_msg = true;
 235         req->status_code = ret;
 236         if (!req->blocked)
 237                 ubus_req_complete_cb(req);
 238
 239         return ret;
 240 }
 241
 242 static void ubus_req_data(struct ubus_request *req, struct ubus_msghdr *hdr)
 243 {
 244         struct ubus_pending_data *data;
 245         int len;
 246
 247         if (!req->blocked) {
 248                 req->blocked = true;
 249                 req_data_cb(req, hdr->type, hdr->data);
 250                 ubus_process_req_data(req);
 251                 req->blocked = false;
 252
 253                 if (req->status_msg)
 254                         ubus_req_complete_cb(req);
 255
 256                 return;
 257         }
 258
 259         len = blob_raw_len(hdr->data);
 260         data = calloc(1, sizeof(*data) + len);
 261         if (!data)
 262                 return;
 263
 264         data->type = hdr->type;
 265         memcpy(data->data, hdr->data, len);
 266         list_add(&data->list, &req->pending);
 267 }
 268
 269 static struct ubus_request *ubus_find_request(struct ubus_context *ctx, uint32_t seq, uint32_t peer)
 270 {
 271         struct ubus_request *req;
 272
 273         list_for_each_entry(req, &ctx->requests, list) {
 274                 if (seq != req->seq || peer != req->peer)
 275                         continue;
 276
 277                 return req;
 278         }
 279         return NULL;
 280 }
 281
 282 static void ubus_process_invoke(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 283 {
 284         struct ubus_request_data req;
 285         struct ubus_object *obj;
 286         uint32_t objid = 0;
 287         int method;
 288         int ret = 0;
 289
 290         ubus_parse_msg(hdr->data);
 291
 292         if (!attrbuf[UBUS_ATTR_OBJID])
 293                 return;
 294
 295         objid = blob_get_int32(attrbuf[UBUS_ATTR_OBJID]);
 296
 297         if (!attrbuf[UBUS_ATTR_METHOD]) {
 298                 ret = UBUS_STATUS_INVALID_ARGUMENT;
 299                 goto send;
 300         }
 301
 302         obj = avl_find_element(&ctx->objects, &objid, obj, avl);
 303         if (!obj) {
 304                 ret = UBUS_STATUS_NOT_FOUND;
 305                 goto send;
 306         }
 307
 308         for (method = 0; method < obj->n_methods; method++)
 309                 if (!strcmp(obj->methods[method].name,
 310                             blob_data(attrbuf[UBUS_ATTR_METHOD])))
 311                         goto found;
 312
 313         /* not found */
 314         ret = UBUS_STATUS_METHOD_NOT_FOUND;
 315         goto send;
 316
 317 found:
 318         req.object = objid;
 319         req.peer = hdr->peer;
 320         req.seq = hdr->seq;
 321         ret = obj->methods[method].handler(ctx, obj, &req,
 322                                            obj->methods[method].name,
 323                                            attrbuf[UBUS_ATTR_DATA]);
 324
 325 send:
 326         blob_buf_init(&b, 0);
 327         blob_put_int32(&b, UBUS_ATTR_STATUS, ret);
 328         blob_put_int32(&b, UBUS_ATTR_OBJID, objid);
 329         ubus_send_msg(ctx, hdr->seq, b.head, UBUS_MSG_STATUS, hdr->peer);
 330 }
 331
 332 static void ubus_process_msg(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 333 {
 334         struct ubus_request *req;
 335
 336         switch(hdr->type) {
 337         case UBUS_MSG_STATUS:
 338                 req = ubus_find_request(ctx, hdr->seq, hdr->peer);
 339                 if (!req)
 340                         break;
 341
 342                 ubus_process_req_status(req, hdr);
 343                 break;
 344
 345         case UBUS_MSG_DATA:
 346                 req = ubus_find_request(ctx, hdr->seq, hdr->peer);
 347                 if (req && (req->data_cb || req->raw_data_cb))
 348                         ubus_req_data(req, hdr);
 349                 break;
 350
 351         case UBUS_MSG_INVOKE:
 352                 ubus_process_invoke(ctx, hdr);
 353                 break;
 354         default:
 355                 DPRINTF("unknown message type: %d\n", hdr->type);
 356                 break;
 357         }
 358 }
 359
 360 void ubus_abort_request(struct ubus_context *ctx, struct ubus_request *req)
 361 {
 362         if (!list_empty(&req->list))
 363                 return;
 364
 365         req->cancelled = true;
 366         ubus_process_req_data(req);
 367         list_del(&req->list);
 368 }
 369
 370 void ubus_complete_request_async(struct ubus_context *ctx, struct ubus_request *req)
 371 {
 372         if (!list_empty(&req->list))
 373                 return;
 374
 375         list_add(&req->list, &ctx->requests);
 376 }
 377
 378 static void ubus_handle_data(struct uloop_fd *u, unsigned int events)
 379 {
 380         struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
 381         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 382
 383         while (get_next_msg(ctx, false))
 384                 ubus_process_msg(ctx, hdr);
 385
 386         if (u->eof)
 387                 ctx->connection_lost(ctx);
 388 }
 389
 390 int ubus_complete_request(struct ubus_context *ctx, struct ubus_request *req)
 391 {
 392         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 393
 394         if (!list_empty(&req->list))
 395                 list_del(&req->list);
 396
 397         while (1) {
 398                 if (req->status_msg)
 399                         return req->status_code;
 400
 401                 if (req->cancelled)
 402                         return UBUS_STATUS_NO_DATA;
 403
 404                 if (!get_next_msg(ctx, true))
 405                         return UBUS_STATUS_NO_DATA;
 406
 407                 if (hdr->seq != req->seq || hdr->peer != req->peer)
 408                         goto skip;
 409
 410                 switch(hdr->type) {
 411                 case UBUS_MSG_STATUS:
 412                         return ubus_process_req_status(req, hdr);
 413                 case UBUS_MSG_DATA:
 414                         if (req->data_cb || req->raw_data_cb)
 415                                 ubus_req_data(req, hdr);
 416                         continue;
 417                 default:
 418                         goto skip;
 419                 }
 420
 421 skip:
 422                 ubus_process_msg(ctx, hdr);
 423         }
 424 }
 425
 426 int ubus_send_reply(struct ubus_context *ctx, struct ubus_request_data *req,
 427                     struct blob_attr *msg)
 428 {
 429         int ret;
 430
 431         blob_buf_init(&b, 0);
 432         blob_put_int32(&b, UBUS_ATTR_OBJID, req->object);
 433         blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
 434         ret = ubus_send_msg(ctx, req->seq, b.head, UBUS_MSG_DATA, req->peer);
 435         if (ret < 0)
 436                 return UBUS_STATUS_NO_DATA;
 437
 438         return 0;
 439 }
 440
 441 void ubus_invoke_async(struct ubus_context *ctx, uint32_t obj, const char *method,
 442                        struct blob_attr *msg, struct ubus_request *req)
 443 {
 444         blob_buf_init(&b, 0);
 445         blob_put_int32(&b, UBUS_ATTR_OBJID, obj);
 446         blob_put_string(&b, UBUS_ATTR_METHOD, method);
 447         if (msg)
 448                 blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
 449
 450         ubus_start_request(ctx, req, b.head, UBUS_MSG_INVOKE, obj);
 451 }
 452
 453 int ubus_invoke(struct ubus_context *ctx, uint32_t obj, const char *method,
 454                 struct blob_attr *msg, ubus_data_handler_t cb, void *priv)
 455 {
 456         struct ubus_request req;
 457
 458         ubus_invoke_async(ctx, obj, method, msg, &req);
 459         req.data_cb = cb;
 460         req.priv = priv;
 461         return ubus_complete_request(ctx, &req);
 462 }
 463
 464 static void ubus_publish_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 465 {
 466         struct ubus_object *obj = req->priv;
 467
 468         ubus_parse_msg(msg);
 469
 470         if (!attrbuf[UBUS_ATTR_OBJID])
 471                 return;
 472
 473         obj->id = blob_get_int32(attrbuf[UBUS_ATTR_OBJID]);
 474
 475         if (attrbuf[UBUS_ATTR_OBJTYPE])
 476                 obj->type->id = blob_get_int32(attrbuf[UBUS_ATTR_OBJTYPE]);
 477
 478         obj->avl.key = &obj->id;
 479         avl_insert(&req->ctx->objects, &obj->avl);
 480 }
 481
 482 static bool ubus_push_table_data(const struct ubus_signature **sig, int *rem, bool array)
 483 {
 484         const struct ubus_signature *cur;
 485         bool nest_type;
 486         void *nest;
 487
 488         while (rem) {
 489                 cur = (*sig)++;
 490                 (*rem)--;
 491                 switch(cur->type) {
 492                 case UBUS_SIGNATURE_END:
 493                         return !array;
 494                 case BLOBMSG_TYPE_INT32:
 495                 case BLOBMSG_TYPE_STRING:
 496                         blobmsg_add_u32(&b, cur->name, cur->type);
 497                         break;
 498                 case BLOBMSG_TYPE_TABLE:
 499                 case BLOBMSG_TYPE_ARRAY:
 500                         nest_type = cur->type == BLOBMSG_TYPE_ARRAY;
 501                         nest = blobmsg_open_nested(&b, cur->name, nest_type);
 502                         if (!ubus_push_table_data(sig, rem, nest_type))
 503                                 return false;
 504                         blobmsg_close_table(&b, nest);
 505                         break;
 506                 default:
 507                         return false;
 508                 }
 509                 if (array)
 510                         return true;
 511         }
 512         return false;
 513 }
 514
 515 static bool ubus_push_object_type(struct ubus_object_type *type)
 516 {
 517         void *s, *m;
 518         int rem = type->n_signature;
 519         const struct ubus_signature *sig = type->signature;
 520
 521         s = blob_nest_start(&b, UBUS_ATTR_SIGNATURE);
 522         while (rem) {
 523                 if (sig->type != UBUS_SIGNATURE_METHOD)
 524                         return false;
 525
 526                 m = blobmsg_open_table(&b, sig->name);
 527
 528                 sig++;
 529                 rem--;
 530                 if (!ubus_push_table_data(&sig, &rem, false))
 531                         return false;
 532
 533                 blobmsg_close_table(&b, m);
 534         }
 535         blob_nest_end(&b, s);
 536
 537         return true;
 538 }
 539
 540 int ubus_publish(struct ubus_context *ctx, struct ubus_object *obj)
 541 {
 542         struct ubus_request req;
 543         int ret;
 544
 545         if (obj->id || !obj->name || !obj->type)
 546                 return UBUS_STATUS_INVALID_ARGUMENT;
 547
 548         blob_buf_init(&b, 0);
 549         blob_put_string(&b, UBUS_ATTR_OBJPATH, obj->name);
 550
 551         if (obj->type->id)
 552                 blob_put_int32(&b, UBUS_ATTR_OBJTYPE, obj->type->id);
 553         else if (!ubus_push_object_type(obj->type))
 554                 return UBUS_STATUS_INVALID_ARGUMENT;
 555
 556         ubus_start_request(ctx, &req, b.head, UBUS_MSG_PUBLISH, 0);
 557         req.raw_data_cb = ubus_publish_cb;
 558         req.priv = obj;
 559         ret = ubus_complete_request(ctx, &req);
 560         if (ret)
 561                 return ret;
 562
 563         if (!obj->id)
 564                 return UBUS_STATUS_NO_DATA;
 565
 566         return 0;
 567 }
 568
 569 void ubus_default_connection_lost(struct ubus_context *ctx)
 570 {
 571         if (ctx->sock.registered)
 572                 uloop_end();
 573 }
 574
 575 struct ubus_context *ubus_connect(const char *path)
 576 {
 577         struct ubus_context *ctx;
 578         struct {
 579                 struct ubus_msghdr hdr;
 580                 struct blob_attr data;
 581         } hdr;
 582         struct blob_attr *buf;
 583
 584         if (!path)
 585                 path = UBUS_UNIX_SOCKET;
 586
 587         ctx = calloc(1, sizeof(*ctx));
 588         if (!ctx)
 589                 goto error;
 590
 591         ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
 592         if (ctx->sock.fd < 0) {
 593                 DPRINTF("Failed to connect to server\n");
 594                 goto error_free;
 595         }
 596         ctx->sock.cb = ubus_handle_data;
 597
 598         if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr)) {
 599                 DPRINTF("Failed to read initial message data\n");
 600                 goto error_close;
 601         }
 602
 603         if (!ubus_validate_hdr(&hdr.hdr)) {
 604                 DPRINTF("Failed to validate initial message header\n");
 605                 goto error_close;
 606         }
 607
 608         if (hdr.hdr.type != UBUS_MSG_HELLO) {
 609                 DPRINTF("Unexpected initial message\n");
 610                 goto error_close;
 611         }
 612
 613         buf = calloc(1, blob_raw_len(&hdr.data));
 614         if (!buf)
 615                 goto error_close;
 616
 617         memcpy(buf, &hdr.data, sizeof(hdr.data));
 618         if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf)) {
 619                 DPRINTF("Failed to retrieve initial message data\n");
 620                 goto error_free_buf;
 621         }
 622
 623         ctx->local_id = hdr.hdr.peer;
 624         free(buf);
 625
 626         ctx->connection_lost = ubus_default_connection_lost;
 627
 628         INIT_LIST_HEAD(&ctx->requests);
 629         avl_init(&ctx->objects, ubus_cmp_id, false, NULL);
 630
 631         if (!ctx->local_id) {
 632                 DPRINTF("Failed to get local peer id\n");
 633                 goto error_close;
 634         }
 635
 636         return ctx;
 637
 638 error_free_buf:
 639         free(buf);
 640 error_close:
 641         close(ctx->sock.fd);
 642 error_free:
 643         free(ctx);
 644 error:
 645         return NULL;
 646 }
 647
 648 void ubus_free(struct ubus_context *ctx)
 649 {
 650         close(ctx->sock.fd);
 651         free(ctx);
 652 }