file.c

   1 /*
   2  * rpcd - UBUS RPC server
   3  *
   4  *   Copyright (C) 2013 Jo-Philipp Wich <jow@openwrt.org>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include <fcntl.h>
  20 #include <errno.h>
  21 #include <unistd.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <limits.h>
  25 #include <dirent.h>
  26 #include <sys/stat.h>
  27 #include <sys/wait.h>
  28 #include <libubus.h>
  29 #include <libubox/blobmsg.h>
  30 #include <libubox/ustream.h>
  31
  32 #include "plugin.h"
  33
  34 /* limit of sys & proc files */
  35 #define RPC_FILE_MIN_SIZE               (128)
  36
  37 /* limit of regular files and command output data */
  38 #define RPC_FILE_MAX_SIZE               (4096 * 64)
  39 #define RPC_FILE_MAX_RUNTIME    (3 * 1000)
  40
  41 #define ustream_for_each_read_buffer(stream, ptr, len) \
  42         for (ptr = ustream_get_read_buf(stream, &len);     \
  43              ptr != NULL && len > 0;                       \
  44              ustream_consume(stream, len), ptr = ustream_get_read_buf(stream, &len))
  45
  46 #define ustream_declare(us, fd, name)                     \
  47         us.stream.string_data   = true;                       \
  48         us.stream.r.buffer_len  = 4096;                       \
  49         us.stream.r.max_buffers = RPC_FILE_MAX_SIZE / 4096;   \
  50         us.stream.notify_read   = rpc_file_##name##_read_cb;  \
  51         us.stream.notify_state  = rpc_file_##name##_state_cb; \
  52         ustream_fd_init(&us, fd);
  53
  54 struct rpc_file_exec_context {
  55         struct ubus_context *context;
  56         struct ubus_request_data request;
  57         struct uloop_timeout timeout;
  58         struct uloop_process process;
  59         struct ustream_fd opipe;
  60         struct ustream_fd epipe;
  61         int outlen;
  62         char *out;
  63         int errlen;
  64         char *err;
  65         int stat;
  66 };
  67
  68
  69 static struct blob_buf buf;
  70
  71 enum {
  72         RPC_F_PATH,
  73         RPC_F_DATA,
  74         __RPC_F_MAX,
  75 };
  76
  77 static const struct blobmsg_policy rpc_file_policy[__RPC_F_MAX] = {
  78         [RPC_F_PATH] = { .name = "path", .type = BLOBMSG_TYPE_STRING },
  79         [RPC_F_DATA] = { .name = "data", .type = BLOBMSG_TYPE_STRING },
  80 };
  81
  82 enum {
  83         RPC_E_CMD,
  84         RPC_E_PARM,
  85         RPC_E_ENV,
  86         __RPC_E_MAX,
  87 };
  88
  89 static const struct blobmsg_policy rpc_exec_policy[__RPC_E_MAX] = {
  90         [RPC_E_CMD] = { .name = "command", .type = BLOBMSG_TYPE_STRING },
  91         [RPC_E_PARM] = { .name = "params",  .type = BLOBMSG_TYPE_ARRAY  },
  92         [RPC_E_ENV]  = { .name = "env",     .type = BLOBMSG_TYPE_TABLE  },
  93 };
  94
  95 static const char *d_types[] = {
  96         [DT_BLK]     = "block",
  97         [DT_CHR]     = "char",
  98         [DT_DIR]     = "directory",
  99         [DT_FIFO]    = "fifo",
 100         [DT_LNK]     = "symlink",
 101         [DT_REG]     = "file",
 102         [DT_SOCK]    = "socket",
 103         [DT_UNKNOWN] = "unknown",
 104 };
 105
 106
 107 static int
 108 rpc_errno_status(void)
 109 {
 110         switch (errno)
 111         {
 112         case EACCES:
 113                 return UBUS_STATUS_PERMISSION_DENIED;
 114
 115         case ENOTDIR:
 116                 return UBUS_STATUS_INVALID_ARGUMENT;
 117
 118         case ENOENT:
 119                 return UBUS_STATUS_NOT_FOUND;
 120
 121         case EINVAL:
 122                 return UBUS_STATUS_INVALID_ARGUMENT;
 123
 124         default:
 125                 return UBUS_STATUS_UNKNOWN_ERROR;
 126         }
 127 }
 128
 129 static struct blob_attr **
 130 rpc_check_path(struct blob_attr *msg, char **path, struct stat *s)
 131 {
 132         static struct blob_attr *tb[__RPC_F_MAX];
 133
 134         blobmsg_parse(rpc_file_policy, __RPC_F_MAX, tb, blob_data(msg), blob_len(msg));
 135
 136         if (!tb[RPC_F_PATH])
 137         {
 138                 errno = EINVAL;
 139                 return NULL;
 140         }
 141
 142         *path = blobmsg_data(tb[RPC_F_PATH]);
 143
 144         if (stat(*path, s))
 145                 return NULL;
 146
 147         return tb;
 148 }
 149
 150 static int
 151 rpc_file_read(struct ubus_context *ctx, struct ubus_object *obj,
 152               struct ubus_request_data *req, const char *method,
 153               struct blob_attr *msg)
 154 {
 155         int fd, rv, len;
 156         char *path;
 157         struct stat s;
 158         char *wbuf;
 159
 160         if (!rpc_check_path(msg, &path, &s))
 161                 return rpc_errno_status();
 162
 163         if (s.st_size >= RPC_FILE_MAX_SIZE)
 164                 return UBUS_STATUS_NOT_SUPPORTED;
 165
 166         if ((fd = open(path, O_RDONLY)) < 0)
 167                 return rpc_errno_status();
 168
 169         /* some sysfs files do not report a length */
 170         if (s.st_size == 0)
 171                 s.st_size = RPC_FILE_MIN_SIZE;
 172
 173         blob_buf_init(&buf, 0);
 174
 175         wbuf = blobmsg_alloc_string_buffer(&buf, "data", s.st_size + 1);
 176
 177         if (!wbuf)
 178         {
 179                 rv = UBUS_STATUS_UNKNOWN_ERROR;
 180                 goto out;
 181         }
 182
 183         if ((len = read(fd, wbuf, s.st_size)) <= 0)
 184         {
 185                 rv = UBUS_STATUS_NO_DATA;
 186                 goto out;
 187         }
 188
 189         *(wbuf + len) = 0;
 190         blobmsg_add_string_buffer(&buf);
 191
 192         ubus_send_reply(ctx, req, buf.head);
 193         rv = UBUS_STATUS_OK;
 194
 195 out:
 196         close(fd);
 197         return rv;
 198 }
 199
 200 static int
 201 rpc_file_write(struct ubus_context *ctx, struct ubus_object *obj,
 202                struct ubus_request_data *req, const char *method,
 203                struct blob_attr *msg)
 204 {
 205         int fd;
 206         char *path;
 207         struct stat s;
 208         struct blob_attr **tb;
 209
 210         if (!(tb = rpc_check_path(msg, &path, &s)))
 211                 return rpc_errno_status();
 212
 213         if (!tb[RPC_F_DATA])
 214                 return UBUS_STATUS_INVALID_ARGUMENT;
 215
 216         if ((fd = open(path, O_WRONLY)) < 0)
 217                 return rpc_errno_status();
 218
 219         write(fd, blobmsg_data(tb[RPC_F_DATA]), blobmsg_data_len(tb[RPC_F_DATA]));
 220         close(fd);
 221
 222         return 0;
 223 }
 224
 225 static int
 226 rpc_file_list(struct ubus_context *ctx, struct ubus_object *obj,
 227               struct ubus_request_data *req, const char *method,
 228               struct blob_attr *msg)
 229 {
 230         DIR *fd;
 231         void *c, *d;
 232         char *path;
 233         struct stat s;
 234         struct dirent *e;
 235
 236         if (!rpc_check_path(msg, &path, &s))
 237                 return rpc_errno_status();
 238
 239         if ((fd = opendir(path)) == NULL)
 240                 return rpc_errno_status();
 241
 242         blob_buf_init(&buf, 0);
 243         c = blobmsg_open_array(&buf, "entries");
 244
 245         while ((e = readdir(fd)) != NULL)
 246         {
 247                 if (!strcmp(e->d_name, ".") || !strcmp(e->d_name, ".."))
 248                         continue;
 249
 250                 d = blobmsg_open_table(&buf, NULL);
 251                 blobmsg_add_string(&buf, "name", e->d_name);
 252                 blobmsg_add_string(&buf, "type", d_types[e->d_type]);
 253                 blobmsg_close_table(&buf, d);
 254         }
 255
 256         blobmsg_close_array(&buf, c);
 257         ubus_send_reply(ctx, req, buf.head);
 258
 259         return 0;
 260 }
 261
 262 static int
 263 rpc_file_stat(struct ubus_context *ctx, struct ubus_object *obj,
 264               struct ubus_request_data *req, const char *method,
 265               struct blob_attr *msg)
 266 {
 267         int type;
 268         char *path;
 269         struct stat s;
 270
 271         if (!rpc_check_path(msg, &path, &s))
 272                 return rpc_errno_status();
 273
 274         blob_buf_init(&buf, 0);
 275
 276         type = S_ISREG(s.st_mode) ? DT_REG :
 277                 S_ISDIR(s.st_mode) ? DT_DIR :
 278                  S_ISCHR(s.st_mode) ? DT_CHR :
 279                   S_ISBLK(s.st_mode) ? DT_BLK :
 280                    S_ISFIFO(s.st_mode) ? DT_FIFO :
 281                     S_ISLNK(s.st_mode) ? DT_LNK :
 282                      S_ISSOCK(s.st_mode) ? DT_SOCK :
 283                       DT_UNKNOWN;
 284
 285         blobmsg_add_string(&buf, "path", path);
 286         blobmsg_add_string(&buf, "type", d_types[type]);
 287         blobmsg_add_u32(&buf, "size",  s.st_size);
 288         blobmsg_add_u32(&buf, "mode",  s.st_mode);
 289         blobmsg_add_u32(&buf, "atime", s.st_atime);
 290         blobmsg_add_u32(&buf, "mtime", s.st_mtime);
 291         blobmsg_add_u32(&buf, "ctime", s.st_ctime);
 292         blobmsg_add_u32(&buf, "inode", s.st_ino);
 293         blobmsg_add_u32(&buf, "uid",   s.st_uid);
 294         blobmsg_add_u32(&buf, "gid",   s.st_gid);
 295
 296         ubus_send_reply(ctx, req, buf.head);
 297
 298         return 0;
 299 }
 300
 301 static const char *
 302 rpc_file_exec_lookup(const char *cmd)
 303 {
 304         struct stat s;
 305         int plen = 0, clen = strlen(cmd) + 1;
 306         char *search, *p;
 307         static char path[PATH_MAX];
 308
 309         if (!stat(cmd, &s) && S_ISREG(s.st_mode))
 310                 return cmd;
 311
 312         search = getenv("PATH");
 313
 314         if (!search)
 315                 search = "/bin:/usr/bin:/sbin:/usr/sbin";
 316
 317         p = search;
 318
 319         do
 320         {
 321                 if (*p != ':' && *p != '\0')
 322                         continue;
 323
 324                 plen = p - search;
 325
 326                 if ((plen + clen) >= sizeof(path))
 327                         continue;
 328
 329                 strncpy(path, search, plen);
 330                 sprintf(path + plen, "/%s", cmd);
 331
 332                 if (!stat(path, &s) && S_ISREG(s.st_mode))
 333                         return path;
 334
 335                 search = p + 1;
 336         }
 337         while (*p++);
 338
 339         return NULL;
 340 }
 341
 342
 343 static void
 344 rpc_ustream_to_blobmsg(struct ustream *s, const char *name)
 345 {
 346         int len;
 347         char *rbuf, *wbuf;
 348
 349         if ((len = ustream_pending_data(s, false)) > 0)
 350         {
 351                 wbuf = blobmsg_alloc_string_buffer(&buf, name, len + 1);
 352
 353                 if (!wbuf)
 354                         return;
 355
 356                 ustream_for_each_read_buffer(s, rbuf, len)
 357                 {
 358                         memcpy(wbuf, rbuf, len);
 359                         wbuf += len;
 360                 }
 361
 362                 *wbuf = 0;
 363                 blobmsg_add_string_buffer(&buf);
 364         }
 365 }
 366
 367 static void
 368 rpc_file_exec_reply(struct rpc_file_exec_context *c, int rv)
 369 {
 370         uloop_timeout_cancel(&c->timeout);
 371         uloop_process_delete(&c->process);
 372
 373         if (rv == UBUS_STATUS_OK)
 374         {
 375                 blob_buf_init(&buf, 0);
 376
 377                 blobmsg_add_u32(&buf, "code", WEXITSTATUS(c->stat));
 378
 379                 rpc_ustream_to_blobmsg(&c->opipe.stream, "stdout");
 380                 rpc_ustream_to_blobmsg(&c->epipe.stream, "stderr");
 381
 382                 ubus_send_reply(c->context, &c->request, buf.head);
 383         }
 384
 385         ubus_complete_deferred_request(c->context, &c->request, rv);
 386
 387         ustream_free(&c->opipe.stream);
 388         ustream_free(&c->epipe.stream);
 389
 390         close(c->opipe.fd.fd);
 391         close(c->epipe.fd.fd);
 392
 393         free(c);
 394 }
 395
 396 static void
 397 rpc_file_exec_timeout_cb(struct uloop_timeout *t)
 398 {
 399         struct rpc_file_exec_context *c =
 400                 container_of(t, struct rpc_file_exec_context, timeout);
 401
 402         kill(c->process.pid, SIGKILL);
 403         rpc_file_exec_reply(c, UBUS_STATUS_TIMEOUT);
 404 }
 405
 406 static void
 407 rpc_file_exec_process_cb(struct uloop_process *p, int stat)
 408 {
 409         struct rpc_file_exec_context *c =
 410                 container_of(p, struct rpc_file_exec_context, process);
 411
 412         c->stat = stat;
 413
 414         ustream_poll(&c->opipe.stream);
 415         ustream_poll(&c->epipe.stream);
 416 }
 417
 418 static void
 419 rpc_file_exec_opipe_read_cb(struct ustream *s, int bytes)
 420 {
 421         struct rpc_file_exec_context *c =
 422                 container_of(s, struct rpc_file_exec_context, opipe.stream);
 423
 424         if (ustream_read_buf_full(s))
 425                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 426 }
 427
 428 static void
 429 rpc_file_exec_epipe_read_cb(struct ustream *s, int bytes)
 430 {
 431         struct rpc_file_exec_context *c =
 432                 container_of(s, struct rpc_file_exec_context, epipe.stream);
 433
 434         if (ustream_read_buf_full(s))
 435                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 436 }
 437
 438 static void
 439 rpc_file_exec_opipe_state_cb(struct ustream *s)
 440 {
 441         struct rpc_file_exec_context *c =
 442                 container_of(s, struct rpc_file_exec_context, opipe.stream);
 443
 444         if (c->opipe.stream.eof && c->epipe.stream.eof)
 445                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 446 }
 447
 448 static void
 449 rpc_file_exec_epipe_state_cb(struct ustream *s)
 450 {
 451         struct rpc_file_exec_context *c =
 452                 container_of(s, struct rpc_file_exec_context, epipe.stream);
 453
 454         if (c->opipe.stream.eof && c->epipe.stream.eof)
 455                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 456 }
 457
 458 static int
 459 rpc_file_exec_run(const char *cmd,
 460                               const struct blob_attr *arg, const struct blob_attr *env,
 461                   struct ubus_context *ctx, struct ubus_request_data *req)
 462 {
 463         pid_t pid;
 464
 465         int opipe[2];
 466         int epipe[2];
 467
 468         int rem;
 469         struct blob_attr *cur;
 470
 471         char arglen;
 472         char **args;
 473
 474         struct rpc_file_exec_context *c;
 475
 476         cmd = rpc_file_exec_lookup(cmd);
 477
 478         if (!cmd)
 479                 return UBUS_STATUS_NOT_FOUND;
 480
 481         c = malloc(sizeof(*c));
 482
 483         if (!c)
 484                 return UBUS_STATUS_UNKNOWN_ERROR;
 485
 486         if (pipe(opipe) || pipe(epipe))
 487                 return rpc_errno_status();
 488
 489         switch ((pid = fork()))
 490         {
 491         case -1:
 492                 return rpc_errno_status();
 493
 494         case 0:
 495                 uloop_done();
 496
 497                 dup2(opipe[1], 1);
 498                 dup2(epipe[1], 2);
 499
 500                 close(0);
 501                 close(opipe[0]);
 502                 close(opipe[1]);
 503                 close(epipe[0]);
 504                 close(epipe[1]);
 505
 506                 arglen = 2;
 507                 args = malloc(sizeof(char *) * arglen);
 508
 509                 if (!args)
 510                         return UBUS_STATUS_UNKNOWN_ERROR;
 511
 512                 args[0] = (char *)cmd;
 513                 args[1] = NULL;
 514
 515                 if (arg)
 516                 {
 517                         blobmsg_for_each_attr(cur, arg, rem)
 518                         {
 519                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 520                                         continue;
 521
 522                                 arglen++;
 523
 524                                 if (!(args = realloc(args, sizeof(char *) * arglen)))
 525                                         return UBUS_STATUS_UNKNOWN_ERROR;
 526
 527                                 args[arglen-2] = blobmsg_data(cur);
 528                                 args[arglen-1] = NULL;
 529                         }
 530                 }
 531
 532                 if (env)
 533                 {
 534                         blobmsg_for_each_attr(cur, env, rem)
 535                         {
 536                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 537                                         continue;
 538
 539                                 setenv(blobmsg_name(cur), blobmsg_data(cur), 1);
 540                         }
 541                 }
 542
 543                 if (execv(cmd, args))
 544                         return rpc_errno_status();
 545
 546         default:
 547                 memset(c, 0, sizeof(*c));
 548
 549                 ustream_declare(c->opipe, opipe[0], exec_opipe);
 550                 ustream_declare(c->epipe, epipe[0], exec_epipe);
 551
 552                 c->process.pid = pid;
 553                 c->process.cb = rpc_file_exec_process_cb;
 554                 uloop_process_add(&c->process);
 555
 556                 c->timeout.cb = rpc_file_exec_timeout_cb;
 557                 uloop_timeout_set(&c->timeout, RPC_FILE_MAX_RUNTIME);
 558
 559                 close(opipe[1]);
 560                 close(epipe[1]);
 561
 562                 c->context = ctx;
 563                 ubus_defer_request(ctx, req, &c->request);
 564         }
 565
 566         return UBUS_STATUS_OK;
 567 }
 568
 569 static int
 570 rpc_file_exec(struct ubus_context *ctx, struct ubus_object *obj,
 571               struct ubus_request_data *req, const char *method,
 572               struct blob_attr *msg)
 573 {
 574         struct blob_attr *tb[__RPC_E_MAX];
 575
 576         blobmsg_parse(rpc_exec_policy, __RPC_E_MAX, tb,
 577                       blob_data(msg), blob_len(msg));
 578
 579         if (!tb[RPC_E_CMD])
 580                 return UBUS_STATUS_INVALID_ARGUMENT;
 581
 582         return rpc_file_exec_run(blobmsg_data(tb[RPC_E_CMD]),
 583                                                  tb[RPC_E_PARM], tb[RPC_E_ENV], ctx, req);
 584 }
 585
 586
 587 static int
 588 rpc_file_api_init(const struct rpc_daemon_ops *o, struct ubus_context *ctx)
 589 {
 590         static const struct ubus_method file_methods[] = {
 591                 UBUS_METHOD("read",    rpc_file_read,  rpc_file_policy),
 592                 UBUS_METHOD("write",   rpc_file_write, rpc_file_policy),
 593                 UBUS_METHOD("list",    rpc_file_list,  rpc_file_policy),
 594                 UBUS_METHOD("stat",    rpc_file_stat,  rpc_file_policy),
 595                 UBUS_METHOD("exec",    rpc_file_exec,  rpc_exec_policy),
 596         };
 597
 598         static struct ubus_object_type file_type =
 599                 UBUS_OBJECT_TYPE("luci-rpc-file", file_methods);
 600
 601         static struct ubus_object obj = {
 602                 .name = "file",
 603                 .type = &file_type,
 604                 .methods = file_methods,
 605                 .n_methods = ARRAY_SIZE(file_methods),
 606         };
 607
 608         return ubus_add_object(ctx, &obj);
 609 }
 610
 611 const struct rpc_plugin rpc_plugin = {
 612         .init = rpc_file_api_init
 613 };