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