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                 if (!req->cancelled)
 182                         req->data_cb(req, data->type, data->data);
 183                 free(data);
 184         }
 185 }
 186
 187 static void ubus_req_complete_cb(struct ubus_request *req)
 188 {
 189         ubus_complete_handler_t cb = req->complete_cb;
 190
 191         if (!cb)
 192                 return;
 193
 194         req->complete_cb = NULL;
 195         cb(req, req->status_code);
 196 }
 197
 198 static int ubus_process_req_status(struct ubus_request *req, struct ubus_msghdr *hdr)
 199 {
 200         int ret = UBUS_STATUS_INVALID_ARGUMENT;
 201
 202         if (!list_empty(&req->list))
 203                 list_del(&req->list);
 204
 205         ubus_get_status(hdr, &ret);
 206         req->peer = hdr->peer;
 207         req->status_msg = true;
 208         req->status_code = ret;
 209         if (!req->blocked)
 210                 ubus_req_complete_cb(req);
 211
 212         return ret;
 213 }
 214
 215 static void ubus_req_data(struct ubus_request *req, struct ubus_msghdr *hdr)
 216 {
 217         struct ubus_pending_data *data;
 218         int len;
 219
 220         if (!req->blocked) {
 221                 req->blocked = true;
 222                 req->data_cb(req, hdr->type, hdr->data);
 223                 ubus_process_req_data(req);
 224                 req->blocked = false;
 225
 226                 if (req->status_msg)
 227                         ubus_req_complete_cb(req);
 228
 229                 return;
 230         }
 231
 232         len = blob_raw_len(hdr->data);
 233         data = calloc(1, sizeof(*data) + len);
 234         if (!data)
 235                 return;
 236
 237         data->type = hdr->type;
 238         memcpy(data->data, hdr->data, len);
 239         list_add(&data->list, &req->pending);
 240 }
 241
 242 static struct ubus_request *ubus_find_request(struct ubus_context *ctx, uint32_t seq, uint32_t peer)
 243 {
 244         struct ubus_request *req;
 245
 246         list_for_each_entry(req, &ctx->requests, list) {
 247                 if (seq != req->seq || peer != req->peer)
 248                         continue;
 249
 250                 return req;
 251         }
 252         return NULL;
 253 }
 254
 255 static void ubus_process_invoke(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 256 {
 257         uint32_t objid = 0;
 258         int ret = 0;
 259
 260         ubus_parse_msg(hdr->data);
 261
 262         if (attrbuf[UBUS_ATTR_OBJID])
 263                 objid = blob_get_int32(attrbuf[UBUS_ATTR_OBJID]);
 264
 265         blob_buf_init(&b, 0);
 266         blob_put_int32(&b, UBUS_ATTR_STATUS, ret);
 267         blob_put_int32(&b, UBUS_ATTR_OBJID, objid);
 268         ubus_send_msg(ctx, hdr->seq, b.head, UBUS_MSG_STATUS, hdr->peer);
 269 }
 270
 271 static void ubus_process_msg(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 272 {
 273         struct ubus_request *req;
 274
 275         switch(hdr->type) {
 276         case UBUS_MSG_STATUS:
 277                 req = ubus_find_request(ctx, hdr->seq, hdr->peer);
 278                 if (!req)
 279                         break;
 280
 281                 ubus_process_req_status(req, hdr);
 282                 break;
 283
 284         case UBUS_MSG_DATA:
 285                 req = ubus_find_request(ctx, hdr->seq, hdr->peer);
 286                 if (req && req->data_cb)
 287                         ubus_req_data(req, hdr);
 288                 break;
 289
 290         case UBUS_MSG_INVOKE:
 291                 ubus_process_invoke(ctx, hdr);
 292                 break;
 293         default:
 294                 DPRINTF("unknown message type: %d\n", hdr->type);
 295                 break;
 296         }
 297 }
 298
 299 void ubus_abort_request(struct ubus_context *ctx, struct ubus_request *req)
 300 {
 301         if (!list_empty(&req->list))
 302                 return;
 303
 304         req->cancelled = true;
 305         ubus_process_req_data(req);
 306         list_del(&req->list);
 307 }
 308
 309 void ubus_complete_request_async(struct ubus_context *ctx, struct ubus_request *req)
 310 {
 311         if (!list_empty(&req->list))
 312                 return;
 313
 314         list_add(&req->list, &ctx->requests);
 315 }
 316
 317 static void ubus_handle_data(struct uloop_fd *u, unsigned int events)
 318 {
 319         struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
 320         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 321
 322         while (get_next_msg(ctx, false))
 323                 ubus_process_msg(ctx, hdr);
 324 }
 325
 326 int ubus_complete_request(struct ubus_context *ctx, struct ubus_request *req)
 327 {
 328         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 329
 330         if (!list_empty(&req->list))
 331                 list_del(&req->list);
 332
 333         while (1) {
 334                 if (req->status_msg)
 335                         return req->status_code;
 336
 337                 if (req->cancelled)
 338                         return UBUS_STATUS_NO_DATA;
 339
 340                 if (!get_next_msg(ctx, true))
 341                         return UBUS_STATUS_NO_DATA;
 342
 343                 if (hdr->seq != req->seq || hdr->peer != req->peer)
 344                         goto skip;
 345
 346                 switch(hdr->type) {
 347                 case UBUS_MSG_STATUS:
 348                         return ubus_process_req_status(req, hdr);
 349                 case UBUS_MSG_DATA:
 350                         if (req->data_cb)
 351                                 ubus_req_data(req, hdr);
 352                         continue;
 353                 default:
 354                         goto skip;
 355                 }
 356
 357 skip:
 358                 ubus_process_msg(ctx, hdr);
 359         }
 360 }
 361
 362 void ubus_invoke_async(struct ubus_context *ctx, uint32_t obj, const char *method,
 363                        struct blob_attr *msg, struct ubus_request *req)
 364 {
 365         blob_buf_init(&b, 0);
 366         blob_put_int32(&b, UBUS_ATTR_OBJID, obj);
 367         blob_put_string(&b, UBUS_ATTR_METHOD, method);
 368         blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
 369
 370         ubus_start_request(ctx, req, b.head, UBUS_MSG_INVOKE, obj);
 371 }
 372
 373 int ubus_invoke(struct ubus_context *ctx, uint32_t obj, const char *method,
 374                 struct blob_attr *msg, ubus_data_handler_t cb, void *priv)
 375 {
 376         struct ubus_request req;
 377
 378         ubus_invoke_async(ctx, obj, method, msg, &req);
 379         req.data_cb = cb;
 380         req.priv = priv;
 381         return ubus_complete_request(ctx, &req);
 382 }
 383
 384 static void ubus_publish_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 385 {
 386         struct ubus_object *obj = req->priv;
 387
 388         ubus_parse_msg(msg);
 389
 390         if (!attrbuf[UBUS_ATTR_OBJID])
 391                 return;
 392
 393         obj->id = blob_get_int32(attrbuf[UBUS_ATTR_OBJID]);
 394
 395         if (attrbuf[UBUS_ATTR_OBJTYPE])
 396                 obj->type->id = blob_get_int32(attrbuf[UBUS_ATTR_OBJTYPE]);
 397 }
 398
 399 static bool ubus_push_table_data(const struct ubus_signature **sig, int *rem, bool array)
 400 {
 401         const struct ubus_signature *cur;
 402         bool nest_type;
 403         void *nest;
 404
 405         while (rem) {
 406                 cur = (*sig)++;
 407                 (*rem)--;
 408                 switch(cur->type) {
 409                 case UBUS_SIGNATURE_END:
 410                         return !array;
 411                 case BLOBMSG_TYPE_INT32:
 412                 case BLOBMSG_TYPE_STRING:
 413                         blobmsg_add_u32(&b, cur->name, cur->type);
 414                         break;
 415                 case BLOBMSG_TYPE_TABLE:
 416                 case BLOBMSG_TYPE_ARRAY:
 417                         nest_type = cur->type == BLOBMSG_TYPE_ARRAY;
 418                         nest = blobmsg_open_nested(&b, cur->name, nest_type);
 419                         if (!ubus_push_table_data(sig, rem, nest_type))
 420                                 return false;
 421                         blobmsg_close_table(&b, nest);
 422                         break;
 423                 default:
 424                         return false;
 425                 }
 426                 if (array)
 427                         return true;
 428         }
 429         return false;
 430 }
 431
 432 static bool ubus_push_object_type(struct ubus_object_type *type)
 433 {
 434         void *s, *m;
 435         int rem = type->n_signature;
 436         const struct ubus_signature *sig = type->signature;
 437
 438         s = blob_nest_start(&b, UBUS_ATTR_SIGNATURE);
 439         while (rem) {
 440                 if (sig->type != UBUS_SIGNATURE_METHOD)
 441                         return false;
 442
 443                 m = blobmsg_open_table(&b, sig->name);
 444
 445                 sig++;
 446                 rem--;
 447                 if (!ubus_push_table_data(&sig, &rem, false))
 448                         return false;
 449
 450                 blobmsg_close_table(&b, m);
 451         }
 452         blob_nest_end(&b, s);
 453
 454         return true;
 455 }
 456
 457 int ubus_publish(struct ubus_context *ctx, struct ubus_object *obj)
 458 {
 459         struct ubus_request req;
 460         int ret;
 461
 462         if (obj->id || !obj->name || !obj->type)
 463                 return UBUS_STATUS_INVALID_ARGUMENT;
 464
 465         blob_buf_init(&b, 0);
 466         blob_put_string(&b, UBUS_ATTR_OBJPATH, obj->name);
 467         if (obj->parent)
 468                 blob_put_int32(&b, UBUS_ATTR_OBJID, obj->parent->id);
 469
 470         if (obj->type->id)
 471                 blob_put_int32(&b, UBUS_ATTR_OBJTYPE, obj->type->id);
 472         else if (!ubus_push_object_type(obj->type))
 473                 return UBUS_STATUS_INVALID_ARGUMENT;
 474
 475         ubus_start_request(ctx, &req, b.head, UBUS_MSG_PUBLISH, 0);
 476         req.data_cb = ubus_publish_cb;
 477         req.priv = obj;
 478         ret = ubus_complete_request(ctx, &req);
 479         if (ret)
 480                 return ret;
 481
 482         if (!obj->id)
 483                 return UBUS_STATUS_NO_DATA;
 484
 485         return 0;
 486 }
 487
 488 struct ubus_context *ubus_connect(const char *path)
 489 {
 490         struct ubus_context *ctx;
 491         struct {
 492                 struct ubus_msghdr hdr;
 493                 struct blob_attr data;
 494         } hdr;
 495         struct blob_attr *buf;
 496
 497         if (!path)
 498                 path = UBUS_UNIX_SOCKET;
 499
 500         ctx = calloc(1, sizeof(*ctx));
 501         if (!ctx)
 502                 goto error;
 503
 504         ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
 505         if (ctx->sock.fd < 0) {
 506                 DPRINTF("Failed to connect to server\n");
 507                 goto error_free;
 508         }
 509         ctx->sock.cb = ubus_handle_data;
 510
 511         if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr)) {
 512                 DPRINTF("Failed to read initial message data\n");
 513                 goto error_close;
 514         }
 515
 516         if (!ubus_validate_hdr(&hdr.hdr)) {
 517                 DPRINTF("Failed to validate initial message header\n");
 518                 goto error_close;
 519         }
 520
 521         if (hdr.hdr.type != UBUS_MSG_HELLO) {
 522                 DPRINTF("Unexpected initial message\n");
 523                 goto error_close;
 524         }
 525
 526         buf = calloc(1, blob_raw_len(&hdr.data));
 527         if (!buf)
 528                 goto error_close;
 529
 530         memcpy(buf, &hdr.data, sizeof(hdr.data));
 531         if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf)) {
 532                 DPRINTF("Failed to retrieve initial message data\n");
 533                 goto error_free_buf;
 534         }
 535
 536         ctx->local_id = hdr.hdr.peer;
 537         INIT_LIST_HEAD(&ctx->requests);
 538         free(buf);
 539
 540         if (!ctx->local_id) {
 541                 DPRINTF("Failed to get local peer id\n");
 542                 goto error_close;
 543         }
 544
 545         return ctx;
 546
 547 error_free_buf:
 548         free(buf);
 549 error_close:
 550         close(ctx->sock.fd);
 551 error_free:
 552         free(ctx);
 553 error:
 554         return NULL;
 555 }
 556
 557 void ubus_free(struct ubus_context *ctx)
 558 {
 559         close(ctx->sock.fd);
 560         free(ctx);
 561 }