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