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         case UBUS_MSG_NOTIFY:
 237                 ubus_process_notify(ctx, hdr);
 238                 break;
 239         }
 240 }
 241
 242 static void ubus_process_pending_invoke(struct ubus_context *ctx)
 243 {
 244         struct ubus_pending_invoke *pending, *tmp;
 245
 246         list_for_each_entry_safe(pending, tmp, &ctx->pending, list) {
 247                 list_del(&pending->list);
 248                 ubus_process_msg(ctx, &pending->hdr);
 249                 free(pending);
 250                 if (ctx->stack_depth > 2)
 251                         break;
 252         }
 253 }
 254
 255 void ubus_abort_request(struct ubus_context *ctx, struct ubus_request *req)
 256 {
 257         if (!list_empty(&req->list))
 258                 return;
 259
 260         req->cancelled = true;
 261         ubus_process_req_data(req);
 262         list_del_init(&req->list);
 263 }
 264
 265 void ubus_complete_request_async(struct ubus_context *ctx, struct ubus_request *req)
 266 {
 267         if (!list_empty(&req->list))
 268                 return;
 269
 270         list_add(&req->list, &ctx->requests);
 271 }
 272
 273 static void ubus_sync_req_cb(struct ubus_request *req, int ret)
 274 {
 275         req->status_msg = true;
 276         req->status_code = ret;
 277         uloop_end();
 278 }
 279
 280 struct ubus_sync_req_cb {
 281         struct uloop_timeout timeout;
 282         struct ubus_request *req;
 283 };
 284
 285 static void ubus_sync_req_timeout_cb(struct uloop_timeout *timeout)
 286 {
 287         struct ubus_sync_req_cb *cb;
 288
 289         cb = container_of(timeout, struct ubus_sync_req_cb, timeout);
 290         ubus_sync_req_cb(cb->req, UBUS_STATUS_TIMEOUT);
 291 }
 292
 293 int ubus_complete_request(struct ubus_context *ctx, struct ubus_request *req,
 294                           int timeout)
 295 {
 296         struct ubus_sync_req_cb cb;
 297         ubus_complete_handler_t complete_cb = req->complete_cb;
 298         bool registered = ctx->sock.registered;
 299         int status = UBUS_STATUS_NO_DATA;
 300
 301         if (!registered) {
 302                 uloop_init();
 303                 ubus_add_uloop(ctx);
 304         }
 305
 306         if (timeout) {
 307                 memset(&cb, 0, sizeof(cb));
 308                 cb.req = req;
 309                 cb.timeout.cb = ubus_sync_req_timeout_cb;
 310                 uloop_timeout_set(&cb.timeout, timeout);
 311         }
 312
 313         ubus_complete_request_async(ctx, req);
 314         req->complete_cb = ubus_sync_req_cb;
 315
 316         ctx->stack_depth++;
 317         while (!req->status_msg) {
 318                 bool cancelled = uloop_cancelled;
 319                 uloop_cancelled = false;
 320                 uloop_run();
 321                 uloop_cancelled = cancelled;
 322         }
 323         ctx->stack_depth--;
 324
 325         if (timeout)
 326                 uloop_timeout_cancel(&cb.timeout);
 327
 328         if (req->status_msg)
 329                 status = req->status_code;
 330
 331         req->complete_cb = complete_cb;
 332         if (req->complete_cb)
 333                 req->complete_cb(req, status);
 334
 335         if (!registered)
 336                 uloop_fd_delete(&ctx->sock);
 337
 338         if (!ctx->stack_depth)
 339                 ubus_process_pending_invoke(ctx);
 340
 341         return status;
 342 }
 343
 344 struct ubus_lookup_request {
 345         struct ubus_request req;
 346         ubus_lookup_handler_t cb;
 347 };
 348
 349 static void ubus_lookup_cb(struct ubus_request *ureq, int type, struct blob_attr *msg)
 350 {
 351         struct ubus_lookup_request *req;
 352         struct ubus_object_data obj;
 353         struct blob_attr **attr;
 354
 355         req = container_of(ureq, struct ubus_lookup_request, req);
 356         attr = ubus_parse_msg(msg);
 357
 358         if (!attr[UBUS_ATTR_OBJID] || !attr[UBUS_ATTR_OBJPATH] ||
 359             !attr[UBUS_ATTR_OBJTYPE])
 360                 return;
 361
 362         memset(&obj, 0, sizeof(obj));
 363         obj.id = blob_get_u32(attr[UBUS_ATTR_OBJID]);
 364         obj.path = blob_data(attr[UBUS_ATTR_OBJPATH]);
 365         obj.type_id = blob_get_u32(attr[UBUS_ATTR_OBJTYPE]);
 366         obj.signature = attr[UBUS_ATTR_SIGNATURE];
 367         req->cb(ureq->ctx, &obj, ureq->priv);
 368 }
 369
 370 int __hidden ubus_start_request(struct ubus_context *ctx, struct ubus_request *req,
 371                                 struct blob_attr *msg, int cmd, uint32_t peer)
 372 {
 373         memset(req, 0, sizeof(*req));
 374
 375         if (msg && blob_pad_len(msg) > UBUS_MAX_MSGLEN)
 376                 return -1;
 377
 378         INIT_LIST_HEAD(&req->list);
 379         INIT_LIST_HEAD(&req->pending);
 380         req->ctx = ctx;
 381         req->peer = peer;
 382         req->seq = ++ctx->request_seq;
 383         return ubus_send_msg(ctx, req->seq, msg, cmd, peer);
 384 }
 385
 386 int ubus_lookup(struct ubus_context *ctx, const char *path,
 387                 ubus_lookup_handler_t cb, void *priv)
 388 {
 389         struct ubus_lookup_request lookup;
 390
 391         blob_buf_init(&b, 0);
 392         if (path)
 393                 blob_put_string(&b, UBUS_ATTR_OBJPATH, path);
 394
 395         if (ubus_start_request(ctx, &lookup.req, b.head, UBUS_MSG_LOOKUP, 0) < 0)
 396                 return UBUS_STATUS_INVALID_ARGUMENT;
 397
 398         lookup.req.raw_data_cb = ubus_lookup_cb;
 399         lookup.req.priv = priv;
 400         lookup.cb = cb;
 401         return ubus_complete_request(ctx, &lookup.req, 0);
 402 }
 403
 404 static void ubus_lookup_id_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 405 {
 406         struct blob_attr **attr;
 407         uint32_t *id = req->priv;
 408
 409         attr = ubus_parse_msg(msg);
 410
 411         if (!attr[UBUS_ATTR_OBJID])
 412                 return;
 413
 414         *id = blob_get_u32(attr[UBUS_ATTR_OBJID]);
 415 }
 416
 417 int ubus_lookup_id(struct ubus_context *ctx, const char *path, uint32_t *id)
 418 {
 419         struct ubus_request req;
 420
 421         blob_buf_init(&b, 0);
 422         if (path)
 423                 blob_put_string(&b, UBUS_ATTR_OBJPATH, path);
 424
 425         if (ubus_start_request(ctx, &req, b.head, UBUS_MSG_LOOKUP, 0) < 0)
 426                 return UBUS_STATUS_INVALID_ARGUMENT;
 427
 428         req.raw_data_cb = ubus_lookup_id_cb;
 429         req.priv = id;
 430
 431         return ubus_complete_request(ctx, &req, 0);
 432 }
 433
 434 int ubus_send_reply(struct ubus_context *ctx, struct ubus_request_data *req,
 435                     struct blob_attr *msg)
 436 {
 437         int ret;
 438
 439         blob_buf_init(&b, 0);
 440         blob_put_int32(&b, UBUS_ATTR_OBJID, req->object);
 441         blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
 442         ret = ubus_send_msg(ctx, req->seq, b.head, UBUS_MSG_DATA, req->peer);
 443         if (ret < 0)
 444                 return UBUS_STATUS_NO_DATA;
 445
 446         return 0;
 447 }
 448
 449 int ubus_invoke_async(struct ubus_context *ctx, uint32_t obj, const char *method,
 450                        struct blob_attr *msg, struct ubus_request *req)
 451 {
 452         blob_buf_init(&b, 0);
 453         blob_put_int32(&b, UBUS_ATTR_OBJID, obj);
 454         blob_put_string(&b, UBUS_ATTR_METHOD, method);
 455         if (msg)
 456                 blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
 457
 458         if (ubus_start_request(ctx, req, b.head, UBUS_MSG_INVOKE, obj) < 0)
 459                 return UBUS_STATUS_INVALID_ARGUMENT;
 460
 461         return 0;
 462 }
 463
 464 int ubus_invoke(struct ubus_context *ctx, uint32_t obj, const char *method,
 465                 struct blob_attr *msg, ubus_data_handler_t cb, void *priv,
 466                 int timeout)
 467 {
 468         struct ubus_request req;
 469
 470         ubus_invoke_async(ctx, obj, method, msg, &req);
 471         req.data_cb = cb;
 472         req.priv = priv;
 473         return ubus_complete_request(ctx, &req, timeout);
 474 }
 475
 476
 477
 478 static int ubus_event_cb(struct ubus_context *ctx, struct ubus_object *obj,
 479                          struct ubus_request_data *req,
 480                          const char *method, struct blob_attr *msg)
 481 {
 482         struct ubus_event_handler *ev;
 483
 484         ev = container_of(obj, struct ubus_event_handler, obj);
 485         ev->cb(ctx, ev, method, msg);
 486         return 0;
 487 }
 488
 489 static const struct ubus_method event_method = {
 490         .name = NULL,
 491         .handler = ubus_event_cb,
 492 };
 493
 494 int ubus_register_event_handler(struct ubus_context *ctx,
 495                                 struct ubus_event_handler *ev,
 496                                 const char *pattern)
 497 {
 498         struct ubus_object *obj = &ev->obj;
 499         struct blob_buf b2;
 500         int ret;
 501
 502         if (!obj->id) {
 503                 obj->methods = &event_method;
 504                 obj->n_methods = 1;
 505
 506                 if (!!obj->name ^ !!obj->type)
 507                         return UBUS_STATUS_INVALID_ARGUMENT;
 508
 509                 ret = ubus_add_object(ctx, obj);
 510                 if (ret)
 511                         return ret;
 512         }
 513
 514         /* use a second buffer, ubus_invoke() overwrites the primary one */
 515         memset(&b2, 0, sizeof(b2));
 516         blob_buf_init(&b2, 0);
 517         blobmsg_add_u32(&b2, "object", obj->id);
 518         if (pattern)
 519                 blobmsg_add_string(&b2, "pattern", pattern);
 520
 521         return ubus_invoke(ctx, UBUS_SYSTEM_OBJECT_EVENT, "register", b2.head,
 522                           NULL, NULL, 0);
 523 }
 524
 525 int ubus_send_event(struct ubus_context *ctx, const char *id,
 526                     struct blob_attr *data)
 527 {
 528         struct ubus_request req;
 529         void *s;
 530
 531         blob_buf_init(&b, 0);
 532         blob_put_int32(&b, UBUS_ATTR_OBJID, UBUS_SYSTEM_OBJECT_EVENT);
 533         blob_put_string(&b, UBUS_ATTR_METHOD, "send");
 534         s = blob_nest_start(&b, UBUS_ATTR_DATA);
 535         blobmsg_add_string(&b, "id", id);
 536         blobmsg_add_field(&b, BLOBMSG_TYPE_TABLE, "data", blob_data(data), blob_len(data));
 537         blob_nest_end(&b, s);
 538
 539         if (ubus_start_request(ctx, &req, b.head, UBUS_MSG_INVOKE, UBUS_SYSTEM_OBJECT_EVENT) < 0)
 540                 return UBUS_STATUS_INVALID_ARGUMENT;
 541
 542         return ubus_complete_request(ctx, &req, 0);
 543 }
 544
 545 static void ubus_default_connection_lost(struct ubus_context *ctx)
 546 {
 547         if (ctx->sock.registered)
 548                 uloop_end();
 549 }
 550
 551 struct ubus_context *ubus_connect(const char *path)
 552 {
 553         struct ubus_context *ctx;
 554
 555         ctx = calloc(1, sizeof(*ctx));
 556         if (!ctx)
 557                 return NULL;
 558
 559         ctx->sock.fd = -1;
 560         ctx->sock.cb = ubus_handle_data;
 561         ctx->connection_lost = ubus_default_connection_lost;
 562
 563         INIT_LIST_HEAD(&ctx->requests);
 564         INIT_LIST_HEAD(&ctx->pending);
 565         avl_init(&ctx->objects, ubus_cmp_id, false, NULL);
 566         if (ubus_reconnect(ctx, path)) {
 567                 free(ctx);
 568                 ctx = NULL;
 569         }
 570
 571         return ctx;
 572 }
 573
 574 void ubus_free(struct ubus_context *ctx)
 575 {
 576         close(ctx->sock.fd);
 577         free(ctx);
 578 }