libubus.c

   1 /*
   2  * Copyright (C) 2011-2012 Felix Fietkau <nbd@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License version 2.1
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <sys/types.h>
  15 #include <sys/socket.h>
  16 #include <unistd.h>
  17
  18 #include <libubox/blob.h>
  19 #include <libubox/blobmsg.h>
  20
  21 #include "libubus.h"
  22 #include "libubus-internal.h"
  23 #include "ubusmsg.h"
  24
  25 const char *__ubus_strerror[__UBUS_STATUS_LAST] = {
  26         [UBUS_STATUS_OK] = "Success",
  27         [UBUS_STATUS_INVALID_COMMAND] = "Invalid command",
  28         [UBUS_STATUS_INVALID_ARGUMENT] = "Invalid argument",
  29         [UBUS_STATUS_METHOD_NOT_FOUND] = "Method not found",
  30         [UBUS_STATUS_NOT_FOUND] = "Not found",
  31         [UBUS_STATUS_NO_DATA] = "No response",
  32         [UBUS_STATUS_PERMISSION_DENIED] = "Permission denied",
  33         [UBUS_STATUS_TIMEOUT] = "Request timed out",
  34         [UBUS_STATUS_NOT_SUPPORTED] = "Operation not supported",
  35         [UBUS_STATUS_UNKNOWN_ERROR] = "Unknown error",
  36         [UBUS_STATUS_CONNECTION_FAILED] = "Connection failed",
  37 };
  38
  39 struct blob_buf b __hidden = {};
  40
  41 struct ubus_pending_data {
  42         struct list_head list;
  43         int type;
  44         struct blob_attr data[];
  45 };
  46
  47 struct ubus_pending_invoke {
  48         struct list_head list;
  49         struct ubus_msghdr hdr;
  50 };
  51
  52 static void ubus_process_pending_invoke(struct ubus_context *ctx);
  53
  54 static int ubus_cmp_id(const void *k1, const void *k2, void *ptr)
  55 {
  56         const uint32_t *id1 = k1, *id2 = k2;
  57
  58         if (*id1 < *id2)
  59                 return -1;
  60         else
  61                 return *id1 > *id2;
  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 bool ubus_get_status(struct ubus_msghdr *hdr, int *ret)
  82 {
  83         struct blob_attr **attrbuf = ubus_parse_msg(hdr->data);
  84
  85         if (!attrbuf[UBUS_ATTR_STATUS])
  86                 return false;
  87
  88         *ret = blob_get_u32(attrbuf[UBUS_ATTR_STATUS]);
  89         return true;
  90 }
  91
  92 static void req_data_cb(struct ubus_request *req, int type, struct blob_attr *data)
  93 {
  94         struct blob_attr **attr;
  95
  96         if (req->raw_data_cb)
  97                 req->raw_data_cb(req, type, data);
  98
  99         if (!req->data_cb)
 100                 return;
 101
 102         attr = ubus_parse_msg(data);
 103         req->data_cb(req, type, attr[UBUS_ATTR_DATA]);
 104 }
 105
 106 static void ubus_process_req_data(struct ubus_request *req)
 107 {
 108         struct ubus_pending_data *data;
 109
 110         while (!list_empty(&req->pending)) {
 111                 data = list_first_entry(&req->pending,
 112                         struct ubus_pending_data, list);
 113                 list_del(&data->list);
 114                 if (!req->cancelled)
 115                         req_data_cb(req, data->type, data->data);
 116                 free(data);
 117         }
 118 }
 119
 120 static void ubus_req_complete_cb(struct ubus_request *req)
 121 {
 122         ubus_complete_handler_t cb = req->complete_cb;
 123
 124         if (!cb)
 125                 return;
 126
 127         req->complete_cb = NULL;
 128         cb(req, req->status_code);
 129 }
 130
 131 static int ubus_process_req_status(struct ubus_request *req, struct ubus_msghdr *hdr)
 132 {
 133         int ret = UBUS_STATUS_INVALID_ARGUMENT;
 134
 135         if (!list_empty(&req->list))
 136                 list_del_init(&req->list);
 137
 138         ubus_get_status(hdr, &ret);
 139         req->peer = hdr->peer;
 140         req->status_msg = true;
 141         req->status_code = ret;
 142         if (!req->blocked)
 143                 ubus_req_complete_cb(req);
 144
 145         return ret;
 146 }
 147
 148 static void ubus_req_data(struct ubus_request *req, struct ubus_msghdr *hdr)
 149 {
 150         struct ubus_pending_data *data;
 151         int len;
 152
 153         if (!req->blocked) {
 154                 req->blocked = true;
 155                 req_data_cb(req, hdr->type, hdr->data);
 156                 ubus_process_req_data(req);
 157                 req->blocked = false;
 158
 159                 if (req->status_msg)
 160                         ubus_req_complete_cb(req);
 161
 162                 return;
 163         }
 164
 165         len = blob_raw_len(hdr->data);
 166         data = calloc(1, sizeof(*data) + len);
 167         if (!data)
 168                 return;
 169
 170         data->type = hdr->type;
 171         memcpy(data->data, hdr->data, len);
 172         list_add(&data->list, &req->pending);
 173 }
 174
 175 static struct ubus_request *ubus_find_request(struct ubus_context *ctx, uint32_t seq, uint32_t peer)
 176 {
 177         struct ubus_request *req;
 178
 179         list_for_each_entry(req, &ctx->requests, list) {
 180                 if (seq != req->seq || peer != req->peer)
 181                         continue;
 182
 183                 return req;
 184         }
 185         return NULL;
 186 }
 187
 188 void ubus_complete_deferred_request(struct ubus_context *ctx, struct ubus_request_data *req, int ret)
 189 {
 190         blob_buf_init(&b, 0);
 191         blob_put_int32(&b, UBUS_ATTR_STATUS, ret);
 192         blob_put_int32(&b, UBUS_ATTR_OBJID, req->object);
 193         ubus_send_msg(ctx, req->seq, b.head, UBUS_MSG_STATUS, req->peer);
 194 }
 195
 196 void __hidden ubus_process_msg(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 197 {
 198         struct ubus_pending_invoke *pending;
 199         struct ubus_request *req;
 200
 201         switch(hdr->type) {
 202         case UBUS_MSG_STATUS:
 203                 req = ubus_find_request(ctx, hdr->seq, hdr->peer);
 204                 if (!req)
 205                         break;
 206
 207                 ubus_process_req_status(req, hdr);
 208                 break;
 209
 210         case UBUS_MSG_DATA:
 211                 req = ubus_find_request(ctx, hdr->seq, hdr->peer);
 212                 if (req && (req->data_cb || req->raw_data_cb))
 213                         ubus_req_data(req, hdr);
 214                 break;
 215
 216         case UBUS_MSG_INVOKE:
 217                 if (ctx->stack_depth > 2) {
 218                         pending = calloc(1, sizeof(*pending) +
 219                                 blob_raw_len(hdr->data));
 220
 221                         if (!pending)
 222                                 return;
 223
 224                         memcpy(&pending->hdr, hdr, sizeof(*hdr) +
 225                                 blob_raw_len(hdr->data));
 226                         list_add(&pending->list, &ctx->pending);
 227                 } else {
 228                         ubus_process_invoke(ctx, hdr);
 229                 }
 230                 break;
 231
 232         case UBUS_MSG_UNSUBSCRIBE:
 233                 ubus_process_unsubscribe(ctx, hdr);
 234                 break;
 235         }
 236 }
 237
 238 static void ubus_process_pending_invoke(struct ubus_context *ctx)
 239 {
 240         struct ubus_pending_invoke *pending, *tmp;
 241
 242         list_for_each_entry_safe(pending, tmp, &ctx->pending, list) {
 243                 list_del(&pending->list);
 244                 ubus_process_msg(ctx, &pending->hdr);
 245                 free(pending);
 246                 if (ctx->stack_depth > 2)
 247                         break;
 248         }
 249 }
 250
 251 void ubus_abort_request(struct ubus_context *ctx, struct ubus_request *req)
 252 {
 253         if (!list_empty(&req->list))
 254                 return;
 255
 256         req->cancelled = true;
 257         ubus_process_req_data(req);
 258         list_del_init(&req->list);
 259 }
 260
 261 void ubus_complete_request_async(struct ubus_context *ctx, struct ubus_request *req)
 262 {
 263         if (!list_empty(&req->list))
 264                 return;
 265
 266         list_add(&req->list, &ctx->requests);
 267 }
 268
 269 static void ubus_sync_req_cb(struct ubus_request *req, int ret)
 270 {
 271         req->status_msg = true;
 272         req->status_code = ret;
 273         uloop_end();
 274 }
 275
 276 struct ubus_sync_req_cb {
 277         struct uloop_timeout timeout;
 278         struct ubus_request *req;
 279 };
 280
 281 static void ubus_sync_req_timeout_cb(struct uloop_timeout *timeout)
 282 {
 283         struct ubus_sync_req_cb *cb;
 284
 285         cb = container_of(timeout, struct ubus_sync_req_cb, timeout);
 286         ubus_sync_req_cb(cb->req, UBUS_STATUS_TIMEOUT);
 287 }
 288
 289 int ubus_complete_request(struct ubus_context *ctx, struct ubus_request *req,
 290                           int timeout)
 291 {
 292         struct ubus_sync_req_cb cb;
 293         ubus_complete_handler_t complete_cb = req->complete_cb;
 294         bool registered = ctx->sock.registered;
 295         int status = UBUS_STATUS_NO_DATA;
 296
 297         if (!registered) {
 298                 uloop_init();
 299                 ubus_add_uloop(ctx);
 300         }
 301
 302         if (timeout) {
 303                 memset(&cb, 0, sizeof(cb));
 304                 cb.req = req;
 305                 cb.timeout.cb = ubus_sync_req_timeout_cb;
 306                 uloop_timeout_set(&cb.timeout, timeout);
 307         }
 308
 309         ubus_complete_request_async(ctx, req);
 310         req->complete_cb = ubus_sync_req_cb;
 311
 312         ctx->stack_depth++;
 313         while (!req->status_msg) {
 314                 bool cancelled = uloop_cancelled;
 315                 uloop_cancelled = false;
 316                 uloop_run();
 317                 uloop_cancelled = cancelled;
 318         }
 319         ctx->stack_depth--;
 320
 321         if (timeout)
 322                 uloop_timeout_cancel(&cb.timeout);
 323
 324         if (req->status_msg)
 325                 status = req->status_code;
 326
 327         req->complete_cb = complete_cb;
 328         if (req->complete_cb)
 329                 req->complete_cb(req, status);
 330
 331         if (!registered)
 332                 uloop_fd_delete(&ctx->sock);
 333
 334         if (!ctx->stack_depth)
 335                 ubus_process_pending_invoke(ctx);
 336
 337         return status;
 338 }
 339
 340 struct ubus_lookup_request {
 341         struct ubus_request req;
 342         ubus_lookup_handler_t cb;
 343 };
 344
 345 static void ubus_lookup_cb(struct ubus_request *ureq, int type, struct blob_attr *msg)
 346 {
 347         struct ubus_lookup_request *req;
 348         struct ubus_object_data obj;
 349         struct blob_attr **attr;
 350
 351         req = container_of(ureq, struct ubus_lookup_request, req);
 352         attr = ubus_parse_msg(msg);
 353
 354         if (!attr[UBUS_ATTR_OBJID] || !attr[UBUS_ATTR_OBJPATH] ||
 355             !attr[UBUS_ATTR_OBJTYPE])
 356                 return;
 357
 358         memset(&obj, 0, sizeof(obj));
 359         obj.id = blob_get_u32(attr[UBUS_ATTR_OBJID]);
 360         obj.path = blob_data(attr[UBUS_ATTR_OBJPATH]);
 361         obj.type_id = blob_get_u32(attr[UBUS_ATTR_OBJTYPE]);
 362         obj.signature = attr[UBUS_ATTR_SIGNATURE];
 363         req->cb(ureq->ctx, &obj, ureq->priv);
 364 }
 365
 366 int __hidden ubus_start_request(struct ubus_context *ctx, struct ubus_request *req,
 367                                 struct blob_attr *msg, int cmd, uint32_t peer)
 368 {
 369         memset(req, 0, sizeof(*req));
 370
 371         if (msg && blob_pad_len(msg) > UBUS_MAX_MSGLEN)
 372                 return -1;
 373
 374         INIT_LIST_HEAD(&req->list);
 375         INIT_LIST_HEAD(&req->pending);
 376         req->ctx = ctx;
 377         req->peer = peer;
 378         req->seq = ++ctx->request_seq;
 379         return ubus_send_msg(ctx, req->seq, msg, cmd, peer);
 380 }
 381
 382 int ubus_lookup(struct ubus_context *ctx, const char *path,
 383                 ubus_lookup_handler_t cb, void *priv)
 384 {
 385         struct ubus_lookup_request lookup;
 386
 387         blob_buf_init(&b, 0);
 388         if (path)
 389                 blob_put_string(&b, UBUS_ATTR_OBJPATH, path);
 390
 391         if (ubus_start_request(ctx, &lookup.req, b.head, UBUS_MSG_LOOKUP, 0) < 0)
 392                 return UBUS_STATUS_INVALID_ARGUMENT;
 393
 394         lookup.req.raw_data_cb = ubus_lookup_cb;
 395         lookup.req.priv = priv;
 396         lookup.cb = cb;
 397         return ubus_complete_request(ctx, &lookup.req, 0);
 398 }
 399
 400 static void ubus_lookup_id_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 401 {
 402         struct blob_attr **attr;
 403         uint32_t *id = req->priv;
 404
 405         attr = ubus_parse_msg(msg);
 406
 407         if (!attr[UBUS_ATTR_OBJID])
 408                 return;
 409
 410         *id = blob_get_u32(attr[UBUS_ATTR_OBJID]);
 411 }
 412
 413 int ubus_lookup_id(struct ubus_context *ctx, const char *path, uint32_t *id)
 414 {
 415         struct ubus_request req;
 416
 417         blob_buf_init(&b, 0);
 418         if (path)
 419                 blob_put_string(&b, UBUS_ATTR_OBJPATH, path);
 420
 421         if (ubus_start_request(ctx, &req, b.head, UBUS_MSG_LOOKUP, 0) < 0)
 422                 return UBUS_STATUS_INVALID_ARGUMENT;
 423
 424         req.raw_data_cb = ubus_lookup_id_cb;
 425         req.priv = id;
 426
 427         return ubus_complete_request(ctx, &req, 0);
 428 }
 429
 430 int ubus_send_reply(struct ubus_context *ctx, struct ubus_request_data *req,
 431                     struct blob_attr *msg)
 432 {
 433         int ret;
 434
 435         blob_buf_init(&b, 0);
 436         blob_put_int32(&b, UBUS_ATTR_OBJID, req->object);
 437         blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
 438         ret = ubus_send_msg(ctx, req->seq, b.head, UBUS_MSG_DATA, req->peer);
 439         if (ret < 0)
 440                 return UBUS_STATUS_NO_DATA;
 441
 442         return 0;
 443 }
 444
 445 int ubus_invoke_async(struct ubus_context *ctx, uint32_t obj, const char *method,
 446                        struct blob_attr *msg, struct ubus_request *req)
 447 {
 448         blob_buf_init(&b, 0);
 449         blob_put_int32(&b, UBUS_ATTR_OBJID, obj);
 450         blob_put_string(&b, UBUS_ATTR_METHOD, method);
 451         if (msg)
 452                 blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
 453
 454         if (ubus_start_request(ctx, req, b.head, UBUS_MSG_INVOKE, obj) < 0)
 455                 return UBUS_STATUS_INVALID_ARGUMENT;
 456
 457         return 0;
 458 }
 459
 460 int ubus_invoke(struct ubus_context *ctx, uint32_t obj, const char *method,
 461                 struct blob_attr *msg, ubus_data_handler_t cb, void *priv,
 462                 int timeout)
 463 {
 464         struct ubus_request req;
 465
 466         ubus_invoke_async(ctx, obj, method, msg, &req);
 467         req.data_cb = cb;
 468         req.priv = priv;
 469         return ubus_complete_request(ctx, &req, timeout);
 470 }
 471
 472
 473
 474 static int ubus_event_cb(struct ubus_context *ctx, struct ubus_object *obj,
 475                          struct ubus_request_data *req,
 476                          const char *method, struct blob_attr *msg)
 477 {
 478         struct ubus_event_handler *ev;
 479
 480         ev = container_of(obj, struct ubus_event_handler, obj);
 481         ev->cb(ctx, ev, method, msg);
 482         return 0;
 483 }
 484
 485 static const struct ubus_method event_method = {
 486         .name = NULL,
 487         .handler = ubus_event_cb,
 488 };
 489
 490 int ubus_register_event_handler(struct ubus_context *ctx,
 491                                 struct ubus_event_handler *ev,
 492                                 const char *pattern)
 493 {
 494         struct ubus_object *obj = &ev->obj;
 495         struct blob_buf b2;
 496         int ret;
 497
 498         if (!obj->id) {
 499                 obj->methods = &event_method;
 500                 obj->n_methods = 1;
 501
 502                 if (!!obj->name ^ !!obj->type)
 503                         return UBUS_STATUS_INVALID_ARGUMENT;
 504
 505                 ret = ubus_add_object(ctx, obj);
 506                 if (ret)
 507                         return ret;
 508         }
 509
 510         /* use a second buffer, ubus_invoke() overwrites the primary one */
 511         memset(&b2, 0, sizeof(b2));
 512         blob_buf_init(&b2, 0);
 513         blobmsg_add_u32(&b2, "object", obj->id);
 514         if (pattern)
 515                 blobmsg_add_string(&b2, "pattern", pattern);
 516
 517         return ubus_invoke(ctx, UBUS_SYSTEM_OBJECT_EVENT, "register", b2.head,
 518                           NULL, NULL, 0);
 519 }
 520
 521 int ubus_send_event(struct ubus_context *ctx, const char *id,
 522                     struct blob_attr *data)
 523 {
 524         struct ubus_request req;
 525         void *s;
 526
 527         blob_buf_init(&b, 0);
 528         blob_put_int32(&b, UBUS_ATTR_OBJID, UBUS_SYSTEM_OBJECT_EVENT);
 529         blob_put_string(&b, UBUS_ATTR_METHOD, "send");
 530         s = blob_nest_start(&b, UBUS_ATTR_DATA);
 531         blobmsg_add_string(&b, "id", id);
 532         blobmsg_add_field(&b, BLOBMSG_TYPE_TABLE, "data", blob_data(data), blob_len(data));
 533         blob_nest_end(&b, s);
 534
 535         if (ubus_start_request(ctx, &req, b.head, UBUS_MSG_INVOKE, UBUS_SYSTEM_OBJECT_EVENT) < 0)
 536                 return UBUS_STATUS_INVALID_ARGUMENT;
 537
 538         return ubus_complete_request(ctx, &req, 0);
 539 }
 540
 541 static void ubus_default_connection_lost(struct ubus_context *ctx)
 542 {
 543         if (ctx->sock.registered)
 544                 uloop_end();
 545 }
 546
 547 struct ubus_context *ubus_connect(const char *path)
 548 {
 549         struct ubus_context *ctx;
 550
 551         ctx = calloc(1, sizeof(*ctx));
 552         if (!ctx)
 553                 return NULL;
 554
 555         ctx->sock.fd = -1;
 556         ctx->sock.cb = ubus_handle_data;
 557         ctx->connection_lost = ubus_default_connection_lost;
 558
 559         INIT_LIST_HEAD(&ctx->requests);
 560         INIT_LIST_HEAD(&ctx->pending);
 561         avl_init(&ctx->objects, ubus_cmp_id, false, NULL);
 562         if (ubus_reconnect(ctx, path)) {
 563                 free(ctx);
 564                 ctx = NULL;
 565         }
 566
 567         return ctx;
 568 }
 569
 570 void ubus_free(struct ubus_context *ctx)
 571 {
 572         close(ctx->sock.fd);
 573         free(ctx);
 574 }