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 ubus_process_req_data(struct ubus_request *req)
 187 {
 188         struct ubus_pending_data *data;
 189
 190         while (!list_empty(&req->pending)) {
 191                 data = list_first_entry(&req->pending,
 192                         struct ubus_pending_data, list);
 193                 list_del(&data->list);
 194                 if (!req->cancelled)
 195                         req->data_cb(req, data->type, data->data);
 196                 free(data);
 197         }
 198 }
 199
 200 static void ubus_req_complete_cb(struct ubus_request *req)
 201 {
 202         ubus_complete_handler_t cb = req->complete_cb;
 203
 204         if (!cb)
 205                 return;
 206
 207         req->complete_cb = NULL;
 208         cb(req, req->status_code);
 209 }
 210
 211 static int ubus_process_req_status(struct ubus_request *req, struct ubus_msghdr *hdr)
 212 {
 213         int ret = UBUS_STATUS_INVALID_ARGUMENT;
 214
 215         if (!list_empty(&req->list))
 216                 list_del(&req->list);
 217
 218         ubus_get_status(hdr, &ret);
 219         req->peer = hdr->peer;
 220         req->status_msg = true;
 221         req->status_code = ret;
 222         if (!req->blocked)
 223                 ubus_req_complete_cb(req);
 224
 225         return ret;
 226 }
 227
 228 static void ubus_req_data(struct ubus_request *req, struct ubus_msghdr *hdr)
 229 {
 230         struct ubus_pending_data *data;
 231         int len;
 232
 233         if (!req->blocked) {
 234                 req->blocked = true;
 235                 req->data_cb(req, hdr->type, hdr->data);
 236                 ubus_process_req_data(req);
 237                 req->blocked = false;
 238
 239                 if (req->status_msg)
 240                         ubus_req_complete_cb(req);
 241
 242                 return;
 243         }
 244
 245         len = blob_raw_len(hdr->data);
 246         data = calloc(1, sizeof(*data) + len);
 247         if (!data)
 248                 return;
 249
 250         data->type = hdr->type;
 251         memcpy(data->data, hdr->data, len);
 252         list_add(&data->list, &req->pending);
 253 }
 254
 255 static struct ubus_request *ubus_find_request(struct ubus_context *ctx, uint32_t seq, uint32_t peer)
 256 {
 257         struct ubus_request *req;
 258
 259         list_for_each_entry(req, &ctx->requests, list) {
 260                 if (seq != req->seq || peer != req->peer)
 261                         continue;
 262
 263                 return req;
 264         }
 265         return NULL;
 266 }
 267
 268 static void ubus_process_invoke(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 269 {
 270         struct ubus_request_data req;
 271         struct ubus_object *obj;
 272         uint32_t objid = 0;
 273         int method;
 274         int ret = 0;
 275
 276         ubus_parse_msg(hdr->data);
 277
 278         if (!attrbuf[UBUS_ATTR_METHOD] || !attrbuf[UBUS_ATTR_OBJID]) {
 279                 ret = UBUS_STATUS_INVALID_ARGUMENT;
 280                 goto send;
 281         }
 282
 283         objid = blob_get_int32(attrbuf[UBUS_ATTR_OBJID]);
 284         obj = avl_find_element(&ctx->objects, &objid, obj, avl);
 285         if (!obj) {
 286                 ret = UBUS_STATUS_NOT_FOUND;
 287                 goto send;
 288         }
 289
 290         for (method = 0; method < obj->n_methods; method++)
 291                 if (!strcmp(obj->methods[method].name,
 292                             blob_data(attrbuf[UBUS_ATTR_METHOD])))
 293                         goto found;
 294
 295         /* not found */
 296         ret = UBUS_STATUS_METHOD_NOT_FOUND;
 297         goto send;
 298
 299 found:
 300         req.object = objid;
 301         req.peer = hdr->peer;
 302         req.seq = hdr->seq;
 303         ret = obj->methods[method].handler(obj, &req, obj->methods[method].name,
 304                                            attrbuf[UBUS_ATTR_DATA]);
 305
 306 send:
 307         blob_buf_init(&b, 0);
 308         blob_put_int32(&b, UBUS_ATTR_STATUS, ret);
 309         blob_put_int32(&b, UBUS_ATTR_OBJID, objid);
 310         ubus_send_msg(ctx, hdr->seq, b.head, UBUS_MSG_STATUS, hdr->peer);
 311 }
 312
 313 static void ubus_process_msg(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 314 {
 315         struct ubus_request *req;
 316
 317         switch(hdr->type) {
 318         case UBUS_MSG_STATUS:
 319                 req = ubus_find_request(ctx, hdr->seq, hdr->peer);
 320                 if (!req)
 321                         break;
 322
 323                 ubus_process_req_status(req, hdr);
 324                 break;
 325
 326         case UBUS_MSG_DATA:
 327                 req = ubus_find_request(ctx, hdr->seq, hdr->peer);
 328                 if (req && req->data_cb)
 329                         ubus_req_data(req, hdr);
 330                 break;
 331
 332         case UBUS_MSG_INVOKE:
 333                 ubus_process_invoke(ctx, hdr);
 334                 break;
 335         default:
 336                 DPRINTF("unknown message type: %d\n", hdr->type);
 337                 break;
 338         }
 339 }
 340
 341 void ubus_abort_request(struct ubus_context *ctx, struct ubus_request *req)
 342 {
 343         if (!list_empty(&req->list))
 344                 return;
 345
 346         req->cancelled = true;
 347         ubus_process_req_data(req);
 348         list_del(&req->list);
 349 }
 350
 351 void ubus_complete_request_async(struct ubus_context *ctx, struct ubus_request *req)
 352 {
 353         if (!list_empty(&req->list))
 354                 return;
 355
 356         list_add(&req->list, &ctx->requests);
 357 }
 358
 359 static void ubus_handle_data(struct uloop_fd *u, unsigned int events)
 360 {
 361         struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
 362         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 363
 364         while (get_next_msg(ctx, false))
 365                 ubus_process_msg(ctx, hdr);
 366 }
 367
 368 int ubus_complete_request(struct ubus_context *ctx, struct ubus_request *req)
 369 {
 370         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 371
 372         if (!list_empty(&req->list))
 373                 list_del(&req->list);
 374
 375         while (1) {
 376                 if (req->status_msg)
 377                         return req->status_code;
 378
 379                 if (req->cancelled)
 380                         return UBUS_STATUS_NO_DATA;
 381
 382                 if (!get_next_msg(ctx, true))
 383                         return UBUS_STATUS_NO_DATA;
 384
 385                 if (hdr->seq != req->seq || hdr->peer != req->peer)
 386                         goto skip;
 387
 388                 switch(hdr->type) {
 389                 case UBUS_MSG_STATUS:
 390                         return ubus_process_req_status(req, hdr);
 391                 case UBUS_MSG_DATA:
 392                         if (req->data_cb)
 393                                 ubus_req_data(req, hdr);
 394                         continue;
 395                 default:
 396                         goto skip;
 397                 }
 398
 399 skip:
 400                 ubus_process_msg(ctx, hdr);
 401         }
 402 }
 403
 404 void ubus_invoke_async(struct ubus_context *ctx, uint32_t obj, const char *method,
 405                        struct blob_attr *msg, struct ubus_request *req)
 406 {
 407         blob_buf_init(&b, 0);
 408         blob_put_int32(&b, UBUS_ATTR_OBJID, obj);
 409         blob_put_string(&b, UBUS_ATTR_METHOD, method);
 410         blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
 411
 412         ubus_start_request(ctx, req, b.head, UBUS_MSG_INVOKE, obj);
 413 }
 414
 415 int ubus_invoke(struct ubus_context *ctx, uint32_t obj, const char *method,
 416                 struct blob_attr *msg, ubus_data_handler_t cb, void *priv)
 417 {
 418         struct ubus_request req;
 419
 420         ubus_invoke_async(ctx, obj, method, msg, &req);
 421         req.data_cb = cb;
 422         req.priv = priv;
 423         return ubus_complete_request(ctx, &req);
 424 }
 425
 426 static void ubus_publish_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 427 {
 428         struct ubus_object *obj = req->priv;
 429
 430         ubus_parse_msg(msg);
 431
 432         if (!attrbuf[UBUS_ATTR_OBJID])
 433                 return;
 434
 435         obj->id = blob_get_int32(attrbuf[UBUS_ATTR_OBJID]);
 436
 437         if (attrbuf[UBUS_ATTR_OBJTYPE])
 438                 obj->type->id = blob_get_int32(attrbuf[UBUS_ATTR_OBJTYPE]);
 439
 440         obj->avl.key = &obj->id;
 441         avl_insert(&req->ctx->objects, &obj->avl);
 442 }
 443
 444 static bool ubus_push_table_data(const struct ubus_signature **sig, int *rem, bool array)
 445 {
 446         const struct ubus_signature *cur;
 447         bool nest_type;
 448         void *nest;
 449
 450         while (rem) {
 451                 cur = (*sig)++;
 452                 (*rem)--;
 453                 switch(cur->type) {
 454                 case UBUS_SIGNATURE_END:
 455                         return !array;
 456                 case BLOBMSG_TYPE_INT32:
 457                 case BLOBMSG_TYPE_STRING:
 458                         blobmsg_add_u32(&b, cur->name, cur->type);
 459                         break;
 460                 case BLOBMSG_TYPE_TABLE:
 461                 case BLOBMSG_TYPE_ARRAY:
 462                         nest_type = cur->type == BLOBMSG_TYPE_ARRAY;
 463                         nest = blobmsg_open_nested(&b, cur->name, nest_type);
 464                         if (!ubus_push_table_data(sig, rem, nest_type))
 465                                 return false;
 466                         blobmsg_close_table(&b, nest);
 467                         break;
 468                 default:
 469                         return false;
 470                 }
 471                 if (array)
 472                         return true;
 473         }
 474         return false;
 475 }
 476
 477 static bool ubus_push_object_type(struct ubus_object_type *type)
 478 {
 479         void *s, *m;
 480         int rem = type->n_signature;
 481         const struct ubus_signature *sig = type->signature;
 482
 483         s = blob_nest_start(&b, UBUS_ATTR_SIGNATURE);
 484         while (rem) {
 485                 if (sig->type != UBUS_SIGNATURE_METHOD)
 486                         return false;
 487
 488                 m = blobmsg_open_table(&b, sig->name);
 489
 490                 sig++;
 491                 rem--;
 492                 if (!ubus_push_table_data(&sig, &rem, false))
 493                         return false;
 494
 495                 blobmsg_close_table(&b, m);
 496         }
 497         blob_nest_end(&b, s);
 498
 499         return true;
 500 }
 501
 502 int ubus_publish(struct ubus_context *ctx, struct ubus_object *obj)
 503 {
 504         struct ubus_request req;
 505         int ret;
 506
 507         if (obj->id || !obj->name || !obj->type)
 508                 return UBUS_STATUS_INVALID_ARGUMENT;
 509
 510         blob_buf_init(&b, 0);
 511         blob_put_string(&b, UBUS_ATTR_OBJPATH, obj->name);
 512
 513         if (obj->type->id)
 514                 blob_put_int32(&b, UBUS_ATTR_OBJTYPE, obj->type->id);
 515         else if (!ubus_push_object_type(obj->type))
 516                 return UBUS_STATUS_INVALID_ARGUMENT;
 517
 518         ubus_start_request(ctx, &req, b.head, UBUS_MSG_PUBLISH, 0);
 519         req.data_cb = ubus_publish_cb;
 520         req.priv = obj;
 521         ret = ubus_complete_request(ctx, &req);
 522         if (ret)
 523                 return ret;
 524
 525         if (!obj->id)
 526                 return UBUS_STATUS_NO_DATA;
 527
 528         return 0;
 529 }
 530
 531 struct ubus_context *ubus_connect(const char *path)
 532 {
 533         struct ubus_context *ctx;
 534         struct {
 535                 struct ubus_msghdr hdr;
 536                 struct blob_attr data;
 537         } hdr;
 538         struct blob_attr *buf;
 539
 540         if (!path)
 541                 path = UBUS_UNIX_SOCKET;
 542
 543         ctx = calloc(1, sizeof(*ctx));
 544         if (!ctx)
 545                 goto error;
 546
 547         ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
 548         if (ctx->sock.fd < 0) {
 549                 DPRINTF("Failed to connect to server\n");
 550                 goto error_free;
 551         }
 552         ctx->sock.cb = ubus_handle_data;
 553
 554         if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr)) {
 555                 DPRINTF("Failed to read initial message data\n");
 556                 goto error_close;
 557         }
 558
 559         if (!ubus_validate_hdr(&hdr.hdr)) {
 560                 DPRINTF("Failed to validate initial message header\n");
 561                 goto error_close;
 562         }
 563
 564         if (hdr.hdr.type != UBUS_MSG_HELLO) {
 565                 DPRINTF("Unexpected initial message\n");
 566                 goto error_close;
 567         }
 568
 569         buf = calloc(1, blob_raw_len(&hdr.data));
 570         if (!buf)
 571                 goto error_close;
 572
 573         memcpy(buf, &hdr.data, sizeof(hdr.data));
 574         if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf)) {
 575                 DPRINTF("Failed to retrieve initial message data\n");
 576                 goto error_free_buf;
 577         }
 578
 579         ctx->local_id = hdr.hdr.peer;
 580         free(buf);
 581
 582         INIT_LIST_HEAD(&ctx->requests);
 583         avl_init(&ctx->objects, ubus_cmp_id, false, NULL);
 584
 585         if (!ctx->local_id) {
 586                 DPRINTF("Failed to get local peer id\n");
 587                 goto error_close;
 588         }
 589
 590         return ctx;
 591
 592 error_free_buf:
 593         free(buf);
 594 error_close:
 595         close(ctx->sock.fd);
 596 error_free:
 597         free(ctx);
 598 error:
 599         return NULL;
 600 }
 601
 602 void ubus_free(struct ubus_context *ctx)
 603 {
 604         close(ctx->sock.fd);
 605         free(ctx);
 606 }