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