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         case UBUS_MSG_UNSUBSCRIBE:
 218         case UBUS_MSG_NOTIFY:
 219                 if (ctx->stack_depth > 2) {
 220                         pending = calloc(1, sizeof(*pending) +
 221                                 blob_raw_len(hdr->data));
 222
 223                         if (!pending)
 224                                 return;
 225
 226                         memcpy(&pending->hdr, hdr, sizeof(*hdr) +
 227                                 blob_raw_len(hdr->data));
 228                         list_add(&pending->list, &ctx->pending);
 229                 } else {
 230                         ubus_process_obj_msg(ctx, hdr);
 231                 }
 232                 break;
 233         }
 234 }
 235
 236 static void ubus_process_pending_invoke(struct ubus_context *ctx)
 237 {
 238         struct ubus_pending_invoke *pending, *tmp;
 239
 240         list_for_each_entry_safe(pending, tmp, &ctx->pending, list) {
 241                 list_del(&pending->list);
 242                 ubus_process_msg(ctx, &pending->hdr);
 243                 free(pending);
 244                 if (ctx->stack_depth > 2)
 245                         break;
 246         }
 247 }
 248
 249 void ubus_abort_request(struct ubus_context *ctx, struct ubus_request *req)
 250 {
 251         if (!list_empty(&req->list))
 252                 return;
 253
 254         req->cancelled = true;
 255         ubus_process_req_data(req);
 256         list_del_init(&req->list);
 257 }
 258
 259 void ubus_complete_request_async(struct ubus_context *ctx, struct ubus_request *req)
 260 {
 261         if (!list_empty(&req->list))
 262                 return;
 263
 264         list_add(&req->list, &ctx->requests);
 265 }
 266
 267 static void ubus_sync_req_cb(struct ubus_request *req, int ret)
 268 {
 269         req->status_msg = true;
 270         req->status_code = ret;
 271         uloop_end();
 272 }
 273
 274 struct ubus_sync_req_cb {
 275         struct uloop_timeout timeout;
 276         struct ubus_request *req;
 277 };
 278
 279 static void ubus_sync_req_timeout_cb(struct uloop_timeout *timeout)
 280 {
 281         struct ubus_sync_req_cb *cb;
 282
 283         cb = container_of(timeout, struct ubus_sync_req_cb, timeout);
 284         ubus_sync_req_cb(cb->req, UBUS_STATUS_TIMEOUT);
 285 }
 286
 287 int ubus_complete_request(struct ubus_context *ctx, struct ubus_request *req,
 288                           int timeout)
 289 {
 290         struct ubus_sync_req_cb cb;
 291         ubus_complete_handler_t complete_cb = req->complete_cb;
 292         bool registered = ctx->sock.registered;
 293         int status = UBUS_STATUS_NO_DATA;
 294
 295         if (!registered) {
 296                 uloop_init();
 297                 ubus_add_uloop(ctx);
 298         }
 299
 300         if (timeout) {
 301                 memset(&cb, 0, sizeof(cb));
 302                 cb.req = req;
 303                 cb.timeout.cb = ubus_sync_req_timeout_cb;
 304                 uloop_timeout_set(&cb.timeout, timeout);
 305         }
 306
 307         ubus_complete_request_async(ctx, req);
 308         req->complete_cb = ubus_sync_req_cb;
 309
 310         ctx->stack_depth++;
 311         while (!req->status_msg) {
 312                 bool cancelled = uloop_cancelled;
 313                 uloop_cancelled = false;
 314                 uloop_run();
 315                 uloop_cancelled = cancelled;
 316         }
 317         ctx->stack_depth--;
 318
 319         if (timeout)
 320                 uloop_timeout_cancel(&cb.timeout);
 321
 322         if (req->status_msg)
 323                 status = req->status_code;
 324
 325         req->complete_cb = complete_cb;
 326         if (req->complete_cb)
 327                 req->complete_cb(req, status);
 328
 329         if (!registered)
 330                 uloop_fd_delete(&ctx->sock);
 331
 332         if (!ctx->stack_depth)
 333                 ubus_process_pending_invoke(ctx);
 334
 335         return status;
 336 }
 337
 338 struct ubus_lookup_request {
 339         struct ubus_request req;
 340         ubus_lookup_handler_t cb;
 341 };
 342
 343 static void ubus_lookup_cb(struct ubus_request *ureq, int type, struct blob_attr *msg)
 344 {
 345         struct ubus_lookup_request *req;
 346         struct ubus_object_data obj;
 347         struct blob_attr **attr;
 348
 349         req = container_of(ureq, struct ubus_lookup_request, req);
 350         attr = ubus_parse_msg(msg);
 351
 352         if (!attr[UBUS_ATTR_OBJID] || !attr[UBUS_ATTR_OBJPATH] ||
 353             !attr[UBUS_ATTR_OBJTYPE])
 354                 return;
 355
 356         memset(&obj, 0, sizeof(obj));
 357         obj.id = blob_get_u32(attr[UBUS_ATTR_OBJID]);
 358         obj.path = blob_data(attr[UBUS_ATTR_OBJPATH]);
 359         obj.type_id = blob_get_u32(attr[UBUS_ATTR_OBJTYPE]);
 360         obj.signature = attr[UBUS_ATTR_SIGNATURE];
 361         req->cb(ureq->ctx, &obj, ureq->priv);
 362 }
 363
 364 int __hidden ubus_start_request(struct ubus_context *ctx, struct ubus_request *req,
 365                                 struct blob_attr *msg, int cmd, uint32_t peer)
 366 {
 367         memset(req, 0, sizeof(*req));
 368
 369         if (msg && blob_pad_len(msg) > UBUS_MAX_MSGLEN)
 370                 return -1;
 371
 372         INIT_LIST_HEAD(&req->list);
 373         INIT_LIST_HEAD(&req->pending);
 374         req->ctx = ctx;
 375         req->peer = peer;
 376         req->seq = ++ctx->request_seq;
 377         return ubus_send_msg(ctx, req->seq, msg, cmd, peer);
 378 }
 379
 380 int ubus_lookup(struct ubus_context *ctx, const char *path,
 381                 ubus_lookup_handler_t cb, void *priv)
 382 {
 383         struct ubus_lookup_request lookup;
 384
 385         blob_buf_init(&b, 0);
 386         if (path)
 387                 blob_put_string(&b, UBUS_ATTR_OBJPATH, path);
 388
 389         if (ubus_start_request(ctx, &lookup.req, b.head, UBUS_MSG_LOOKUP, 0) < 0)
 390                 return UBUS_STATUS_INVALID_ARGUMENT;
 391
 392         lookup.req.raw_data_cb = ubus_lookup_cb;
 393         lookup.req.priv = priv;
 394         lookup.cb = cb;
 395         return ubus_complete_request(ctx, &lookup.req, 0);
 396 }
 397
 398 static void ubus_lookup_id_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 399 {
 400         struct blob_attr **attr;
 401         uint32_t *id = req->priv;
 402
 403         attr = ubus_parse_msg(msg);
 404
 405         if (!attr[UBUS_ATTR_OBJID])
 406                 return;
 407
 408         *id = blob_get_u32(attr[UBUS_ATTR_OBJID]);
 409 }
 410
 411 int ubus_lookup_id(struct ubus_context *ctx, const char *path, uint32_t *id)
 412 {
 413         struct ubus_request req;
 414
 415         blob_buf_init(&b, 0);
 416         if (path)
 417                 blob_put_string(&b, UBUS_ATTR_OBJPATH, path);
 418
 419         if (ubus_start_request(ctx, &req, b.head, UBUS_MSG_LOOKUP, 0) < 0)
 420                 return UBUS_STATUS_INVALID_ARGUMENT;
 421
 422         req.raw_data_cb = ubus_lookup_id_cb;
 423         req.priv = id;
 424
 425         return ubus_complete_request(ctx, &req, 0);
 426 }
 427
 428 int ubus_send_reply(struct ubus_context *ctx, struct ubus_request_data *req,
 429                     struct blob_attr *msg)
 430 {
 431         int ret;
 432
 433         blob_buf_init(&b, 0);
 434         blob_put_int32(&b, UBUS_ATTR_OBJID, req->object);
 435         blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
 436         ret = ubus_send_msg(ctx, req->seq, b.head, UBUS_MSG_DATA, req->peer);
 437         if (ret < 0)
 438                 return UBUS_STATUS_NO_DATA;
 439
 440         return 0;
 441 }
 442
 443 int ubus_invoke_async(struct ubus_context *ctx, uint32_t obj, const char *method,
 444                        struct blob_attr *msg, struct ubus_request *req)
 445 {
 446         blob_buf_init(&b, 0);
 447         blob_put_int32(&b, UBUS_ATTR_OBJID, obj);
 448         blob_put_string(&b, UBUS_ATTR_METHOD, method);
 449         if (msg)
 450                 blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
 451
 452         if (ubus_start_request(ctx, req, b.head, UBUS_MSG_INVOKE, obj) < 0)
 453                 return UBUS_STATUS_INVALID_ARGUMENT;
 454
 455         return 0;
 456 }
 457
 458 int ubus_invoke(struct ubus_context *ctx, uint32_t obj, const char *method,
 459                 struct blob_attr *msg, ubus_data_handler_t cb, void *priv,
 460                 int timeout)
 461 {
 462         struct ubus_request req;
 463
 464         ubus_invoke_async(ctx, obj, method, msg, &req);
 465         req.data_cb = cb;
 466         req.priv = priv;
 467         return ubus_complete_request(ctx, &req, timeout);
 468 }
 469
 470
 471
 472 static int ubus_event_cb(struct ubus_context *ctx, struct ubus_object *obj,
 473                          struct ubus_request_data *req,
 474                          const char *method, struct blob_attr *msg)
 475 {
 476         struct ubus_event_handler *ev;
 477
 478         ev = container_of(obj, struct ubus_event_handler, obj);
 479         ev->cb(ctx, ev, method, msg);
 480         return 0;
 481 }
 482
 483 static const struct ubus_method event_method = {
 484         .name = NULL,
 485         .handler = ubus_event_cb,
 486 };
 487
 488 int ubus_register_event_handler(struct ubus_context *ctx,
 489                                 struct ubus_event_handler *ev,
 490                                 const char *pattern)
 491 {
 492         struct ubus_object *obj = &ev->obj;
 493         struct blob_buf b2;
 494         int ret;
 495
 496         if (!obj->id) {
 497                 obj->methods = &event_method;
 498                 obj->n_methods = 1;
 499
 500                 if (!!obj->name ^ !!obj->type)
 501                         return UBUS_STATUS_INVALID_ARGUMENT;
 502
 503                 ret = ubus_add_object(ctx, obj);
 504                 if (ret)
 505                         return ret;
 506         }
 507
 508         /* use a second buffer, ubus_invoke() overwrites the primary one */
 509         memset(&b2, 0, sizeof(b2));
 510         blob_buf_init(&b2, 0);
 511         blobmsg_add_u32(&b2, "object", obj->id);
 512         if (pattern)
 513                 blobmsg_add_string(&b2, "pattern", pattern);
 514
 515         return ubus_invoke(ctx, UBUS_SYSTEM_OBJECT_EVENT, "register", b2.head,
 516                           NULL, NULL, 0);
 517 }
 518
 519 int ubus_send_event(struct ubus_context *ctx, const char *id,
 520                     struct blob_attr *data)
 521 {
 522         struct ubus_request req;
 523         void *s;
 524
 525         blob_buf_init(&b, 0);
 526         blob_put_int32(&b, UBUS_ATTR_OBJID, UBUS_SYSTEM_OBJECT_EVENT);
 527         blob_put_string(&b, UBUS_ATTR_METHOD, "send");
 528         s = blob_nest_start(&b, UBUS_ATTR_DATA);
 529         blobmsg_add_string(&b, "id", id);
 530         blobmsg_add_field(&b, BLOBMSG_TYPE_TABLE, "data", blob_data(data), blob_len(data));
 531         blob_nest_end(&b, s);
 532
 533         if (ubus_start_request(ctx, &req, b.head, UBUS_MSG_INVOKE, UBUS_SYSTEM_OBJECT_EVENT) < 0)
 534                 return UBUS_STATUS_INVALID_ARGUMENT;
 535
 536         return ubus_complete_request(ctx, &req, 0);
 537 }
 538
 539 static void ubus_default_connection_lost(struct ubus_context *ctx)
 540 {
 541         if (ctx->sock.registered)
 542                 uloop_end();
 543 }
 544
 545 struct ubus_context *ubus_connect(const char *path)
 546 {
 547         struct ubus_context *ctx;
 548
 549         ctx = calloc(1, sizeof(*ctx));
 550         if (!ctx)
 551                 return NULL;
 552
 553         ctx->sock.fd = -1;
 554         ctx->sock.cb = ubus_handle_data;
 555         ctx->connection_lost = ubus_default_connection_lost;
 556
 557         INIT_LIST_HEAD(&ctx->requests);
 558         INIT_LIST_HEAD(&ctx->pending);
 559         avl_init(&ctx->objects, ubus_cmp_id, false, NULL);
 560         if (ubus_reconnect(ctx, path)) {
 561                 free(ctx);
 562                 ctx = NULL;
 563         }
 564
 565         return ctx;
 566 }
 567
 568 void ubus_free(struct ubus_context *ctx)
 569 {
 570         close(ctx->sock.fd);
 571         free(ctx);
 572 }