file.c

   1 /*
   2  * rpcd - UBUS RPC server
   3  *
   4  *   Copyright (C) 2013-2014 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 <rpcd/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_R_PATH,
  73         __RPC_F_R_MAX,
  74 };
  75
  76 static const struct blobmsg_policy rpc_file_r_policy[__RPC_F_R_MAX] = {
  77         [RPC_F_R_PATH] = { .name = "path", .type = BLOBMSG_TYPE_STRING },
  78 };
  79
  80 enum {
  81         RPC_F_RW_PATH,
  82         RPC_F_RW_DATA,
  83         __RPC_F_RW_MAX,
  84 };
  85
  86 static const struct blobmsg_policy rpc_file_rw_policy[__RPC_F_RW_MAX] = {
  87         [RPC_F_RW_PATH] = { .name = "path", .type = BLOBMSG_TYPE_STRING },
  88         [RPC_F_RW_DATA] = { .name = "data", .type = BLOBMSG_TYPE_STRING },
  89 };
  90
  91 enum {
  92         RPC_E_CMD,
  93         RPC_E_PARM,
  94         RPC_E_ENV,
  95         __RPC_E_MAX,
  96 };
  97
  98 static const struct blobmsg_policy rpc_exec_policy[__RPC_E_MAX] = {
  99         [RPC_E_CMD]  = { .name = "command", .type = BLOBMSG_TYPE_STRING },
 100         [RPC_E_PARM] = { .name = "params",  .type = BLOBMSG_TYPE_ARRAY  },
 101         [RPC_E_ENV]  = { .name = "env",     .type = BLOBMSG_TYPE_TABLE  },
 102 };
 103
 104 static const char *d_types[] = {
 105         [DT_BLK]     = "block",
 106         [DT_CHR]     = "char",
 107         [DT_DIR]     = "directory",
 108         [DT_FIFO]    = "fifo",
 109         [DT_LNK]     = "symlink",
 110         [DT_REG]     = "file",
 111         [DT_SOCK]    = "socket",
 112         [DT_UNKNOWN] = "unknown",
 113 };
 114
 115
 116 static int
 117 rpc_errno_status(void)
 118 {
 119         switch (errno)
 120         {
 121         case EACCES:
 122                 return UBUS_STATUS_PERMISSION_DENIED;
 123
 124         case ENOTDIR:
 125                 return UBUS_STATUS_INVALID_ARGUMENT;
 126
 127         case ENOENT:
 128                 return UBUS_STATUS_NOT_FOUND;
 129
 130         case EINVAL:
 131                 return UBUS_STATUS_INVALID_ARGUMENT;
 132
 133         default:
 134                 return UBUS_STATUS_UNKNOWN_ERROR;
 135         }
 136 }
 137
 138 static struct blob_attr **
 139 rpc_check_path(struct blob_attr *msg, char **path, struct stat *s)
 140 {
 141         static struct blob_attr *tb[__RPC_F_R_MAX];
 142
 143         blobmsg_parse(rpc_file_r_policy, __RPC_F_R_MAX, tb, blob_data(msg), blob_len(msg));
 144
 145         if (!tb[RPC_F_R_PATH])
 146         {
 147                 errno = EINVAL;
 148                 return NULL;
 149         }
 150
 151         *path = blobmsg_data(tb[RPC_F_R_PATH]);
 152
 153         if (stat(*path, s))
 154                 return NULL;
 155
 156         return tb;
 157 }
 158
 159 static int
 160 rpc_file_read(struct ubus_context *ctx, struct ubus_object *obj,
 161               struct ubus_request_data *req, const char *method,
 162               struct blob_attr *msg)
 163 {
 164         int fd, rv, len;
 165         char *path;
 166         struct stat s;
 167         char *wbuf;
 168
 169         if (!rpc_check_path(msg, &path, &s))
 170                 return rpc_errno_status();
 171
 172         if (s.st_size >= RPC_FILE_MAX_SIZE)
 173                 return UBUS_STATUS_NOT_SUPPORTED;
 174
 175         if ((fd = open(path, O_RDONLY)) < 0)
 176                 return rpc_errno_status();
 177
 178         /* some sysfs files do not report a length */
 179         if (s.st_size == 0)
 180                 s.st_size = RPC_FILE_MIN_SIZE;
 181
 182         blob_buf_init(&buf, 0);
 183
 184         wbuf = blobmsg_alloc_string_buffer(&buf, "data", s.st_size + 1);
 185
 186         if (!wbuf)
 187         {
 188                 rv = UBUS_STATUS_UNKNOWN_ERROR;
 189                 goto out;
 190         }
 191
 192         if ((len = read(fd, wbuf, s.st_size)) <= 0)
 193         {
 194                 rv = UBUS_STATUS_NO_DATA;
 195                 goto out;
 196         }
 197
 198         *(wbuf + len) = 0;
 199         blobmsg_add_string_buffer(&buf);
 200
 201         ubus_send_reply(ctx, req, buf.head);
 202         blob_buf_free(&buf);
 203         rv = UBUS_STATUS_OK;
 204
 205 out:
 206         close(fd);
 207         return rv;
 208 }
 209
 210 static int
 211 rpc_file_write(struct ubus_context *ctx, struct ubus_object *obj,
 212                struct ubus_request_data *req, const char *method,
 213                struct blob_attr *msg)
 214 {
 215         int fd;
 216         struct blob_attr *tb[__RPC_F_RW_MAX];
 217
 218         blobmsg_parse(rpc_file_rw_policy, __RPC_F_RW_MAX, tb,
 219                       blob_data(msg), blob_len(msg));
 220
 221         if (!tb[RPC_F_RW_PATH] || !tb[RPC_F_RW_DATA])
 222                 return UBUS_STATUS_INVALID_ARGUMENT;
 223
 224         if ((fd = open(blobmsg_data(tb[RPC_F_RW_PATH]), O_CREAT | O_TRUNC | O_WRONLY)) < 0)
 225                 return rpc_errno_status();
 226
 227         if (write(fd, blobmsg_data(tb[RPC_F_RW_DATA]), blobmsg_data_len(tb[RPC_F_RW_DATA])) < 0)
 228                 return rpc_errno_status();
 229
 230         if (fsync(fd) < 0)
 231                 return rpc_errno_status();
 232
 233         close(fd);
 234         sync();
 235
 236         return 0;
 237 }
 238
 239 static int
 240 rpc_file_list(struct ubus_context *ctx, struct ubus_object *obj,
 241               struct ubus_request_data *req, const char *method,
 242               struct blob_attr *msg)
 243 {
 244         DIR *fd;
 245         void *c, *d;
 246         char *path;
 247         struct stat s;
 248         struct dirent *e;
 249
 250         if (!rpc_check_path(msg, &path, &s))
 251                 return rpc_errno_status();
 252
 253         if ((fd = opendir(path)) == NULL)
 254                 return rpc_errno_status();
 255
 256         blob_buf_init(&buf, 0);
 257         c = blobmsg_open_array(&buf, "entries");
 258
 259         while ((e = readdir(fd)) != NULL)
 260         {
 261                 if (!strcmp(e->d_name, ".") || !strcmp(e->d_name, ".."))
 262                         continue;
 263
 264                 d = blobmsg_open_table(&buf, NULL);
 265                 blobmsg_add_string(&buf, "name", e->d_name);
 266                 blobmsg_add_string(&buf, "type", d_types[e->d_type]);
 267                 blobmsg_close_table(&buf, d);
 268         }
 269
 270         blobmsg_close_array(&buf, c);
 271         ubus_send_reply(ctx, req, buf.head);
 272         blob_buf_free(&buf);
 273
 274         return 0;
 275 }
 276
 277 static int
 278 rpc_file_stat(struct ubus_context *ctx, struct ubus_object *obj,
 279               struct ubus_request_data *req, const char *method,
 280               struct blob_attr *msg)
 281 {
 282         int type;
 283         char *path;
 284         struct stat s;
 285
 286         if (!rpc_check_path(msg, &path, &s))
 287                 return rpc_errno_status();
 288
 289         blob_buf_init(&buf, 0);
 290
 291         type = S_ISREG(s.st_mode) ? DT_REG :
 292                 S_ISDIR(s.st_mode) ? DT_DIR :
 293                  S_ISCHR(s.st_mode) ? DT_CHR :
 294                   S_ISBLK(s.st_mode) ? DT_BLK :
 295                    S_ISFIFO(s.st_mode) ? DT_FIFO :
 296                     S_ISLNK(s.st_mode) ? DT_LNK :
 297                      S_ISSOCK(s.st_mode) ? DT_SOCK :
 298                       DT_UNKNOWN;
 299
 300         blobmsg_add_string(&buf, "path", path);
 301         blobmsg_add_string(&buf, "type", d_types[type]);
 302         blobmsg_add_u32(&buf, "size",  s.st_size);
 303         blobmsg_add_u32(&buf, "mode",  s.st_mode);
 304         blobmsg_add_u32(&buf, "atime", s.st_atime);
 305         blobmsg_add_u32(&buf, "mtime", s.st_mtime);
 306         blobmsg_add_u32(&buf, "ctime", s.st_ctime);
 307         blobmsg_add_u32(&buf, "inode", s.st_ino);
 308         blobmsg_add_u32(&buf, "uid",   s.st_uid);
 309         blobmsg_add_u32(&buf, "gid",   s.st_gid);
 310
 311         ubus_send_reply(ctx, req, buf.head);
 312         blob_buf_free(&buf);
 313
 314         return 0;
 315 }
 316
 317 static const char *
 318 rpc_file_exec_lookup(const char *cmd)
 319 {
 320         struct stat s;
 321         int plen = 0, clen = strlen(cmd) + 1;
 322         char *search, *p;
 323         static char path[PATH_MAX];
 324
 325         if (!stat(cmd, &s) && S_ISREG(s.st_mode))
 326                 return cmd;
 327
 328         search = getenv("PATH");
 329
 330         if (!search)
 331                 search = "/bin:/usr/bin:/sbin:/usr/sbin";
 332
 333         p = search;
 334
 335         do
 336         {
 337                 if (*p != ':' && *p != '\0')
 338                         continue;
 339
 340                 plen = p - search;
 341
 342                 if ((plen + clen) >= sizeof(path))
 343                         continue;
 344
 345                 strncpy(path, search, plen);
 346                 sprintf(path + plen, "/%s", cmd);
 347
 348                 if (!stat(path, &s) && S_ISREG(s.st_mode))
 349                         return path;
 350
 351                 search = p + 1;
 352         }
 353         while (*p++);
 354
 355         return NULL;
 356 }
 357
 358
 359 static void
 360 rpc_ustream_to_blobmsg(struct ustream *s, const char *name)
 361 {
 362         int len;
 363         char *rbuf, *wbuf;
 364
 365         if ((len = ustream_pending_data(s, false)) > 0)
 366         {
 367                 wbuf = blobmsg_alloc_string_buffer(&buf, name, len + 1);
 368
 369                 if (!wbuf)
 370                         return;
 371
 372                 ustream_for_each_read_buffer(s, rbuf, len)
 373                 {
 374                         memcpy(wbuf, rbuf, len);
 375                         wbuf += len;
 376                 }
 377
 378                 *wbuf = 0;
 379                 blobmsg_add_string_buffer(&buf);
 380         }
 381 }
 382
 383 static void
 384 rpc_file_exec_reply(struct rpc_file_exec_context *c, int rv)
 385 {
 386         uloop_timeout_cancel(&c->timeout);
 387         uloop_process_delete(&c->process);
 388
 389         if (rv == UBUS_STATUS_OK)
 390         {
 391                 blob_buf_init(&buf, 0);
 392
 393                 blobmsg_add_u32(&buf, "code", WEXITSTATUS(c->stat));
 394
 395                 rpc_ustream_to_blobmsg(&c->opipe.stream, "stdout");
 396                 rpc_ustream_to_blobmsg(&c->epipe.stream, "stderr");
 397
 398                 ubus_send_reply(c->context, &c->request, buf.head);
 399                 blob_buf_free(&buf);
 400         }
 401
 402         ubus_complete_deferred_request(c->context, &c->request, rv);
 403
 404         ustream_free(&c->opipe.stream);
 405         ustream_free(&c->epipe.stream);
 406
 407         close(c->opipe.fd.fd);
 408         close(c->epipe.fd.fd);
 409
 410         free(c);
 411 }
 412
 413 static void
 414 rpc_file_exec_timeout_cb(struct uloop_timeout *t)
 415 {
 416         struct rpc_file_exec_context *c =
 417                 container_of(t, struct rpc_file_exec_context, timeout);
 418
 419         kill(c->process.pid, SIGKILL);
 420         rpc_file_exec_reply(c, UBUS_STATUS_TIMEOUT);
 421 }
 422
 423 static void
 424 rpc_file_exec_process_cb(struct uloop_process *p, int stat)
 425 {
 426         struct rpc_file_exec_context *c =
 427                 container_of(p, struct rpc_file_exec_context, process);
 428
 429         c->stat = stat;
 430
 431         ustream_poll(&c->opipe.stream);
 432         ustream_poll(&c->epipe.stream);
 433 }
 434
 435 static void
 436 rpc_file_exec_opipe_read_cb(struct ustream *s, int bytes)
 437 {
 438         struct rpc_file_exec_context *c =
 439                 container_of(s, struct rpc_file_exec_context, opipe.stream);
 440
 441         if (ustream_read_buf_full(s))
 442                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 443 }
 444
 445 static void
 446 rpc_file_exec_epipe_read_cb(struct ustream *s, int bytes)
 447 {
 448         struct rpc_file_exec_context *c =
 449                 container_of(s, struct rpc_file_exec_context, epipe.stream);
 450
 451         if (ustream_read_buf_full(s))
 452                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 453 }
 454
 455 static void
 456 rpc_file_exec_opipe_state_cb(struct ustream *s)
 457 {
 458         struct rpc_file_exec_context *c =
 459                 container_of(s, struct rpc_file_exec_context, opipe.stream);
 460
 461         if (c->opipe.stream.eof && c->epipe.stream.eof)
 462                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 463 }
 464
 465 static void
 466 rpc_file_exec_epipe_state_cb(struct ustream *s)
 467 {
 468         struct rpc_file_exec_context *c =
 469                 container_of(s, struct rpc_file_exec_context, epipe.stream);
 470
 471         if (c->opipe.stream.eof && c->epipe.stream.eof)
 472                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 473 }
 474
 475 static int
 476 rpc_file_exec_run(const char *cmd,
 477                   const struct blob_attr *arg, const struct blob_attr *env,
 478                   struct ubus_context *ctx, struct ubus_request_data *req)
 479 {
 480         pid_t pid;
 481
 482         int opipe[2];
 483         int epipe[2];
 484
 485         int rem;
 486         struct blob_attr *cur;
 487
 488         char arglen;
 489         char **args;
 490
 491         struct rpc_file_exec_context *c;
 492
 493         cmd = rpc_file_exec_lookup(cmd);
 494
 495         if (!cmd)
 496                 return UBUS_STATUS_NOT_FOUND;
 497
 498         c = malloc(sizeof(*c));
 499
 500         if (!c)
 501                 return UBUS_STATUS_UNKNOWN_ERROR;
 502
 503         if (pipe(opipe) || pipe(epipe))
 504                 return rpc_errno_status();
 505
 506         switch ((pid = fork()))
 507         {
 508         case -1:
 509                 return rpc_errno_status();
 510
 511         case 0:
 512                 uloop_done();
 513
 514                 dup2(opipe[1], 1);
 515                 dup2(epipe[1], 2);
 516
 517                 close(0);
 518                 close(opipe[0]);
 519                 close(opipe[1]);
 520                 close(epipe[0]);
 521                 close(epipe[1]);
 522
 523                 arglen = 2;
 524                 args = malloc(sizeof(char *) * arglen);
 525
 526                 if (!args)
 527                         return UBUS_STATUS_UNKNOWN_ERROR;
 528
 529                 args[0] = (char *)cmd;
 530                 args[1] = NULL;
 531
 532                 if (arg)
 533                 {
 534                         blobmsg_for_each_attr(cur, arg, rem)
 535                         {
 536                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 537                                         continue;
 538
 539                                 arglen++;
 540
 541                                 if (!(args = realloc(args, sizeof(char *) * arglen)))
 542                                         return UBUS_STATUS_UNKNOWN_ERROR;
 543
 544                                 args[arglen-2] = blobmsg_data(cur);
 545                                 args[arglen-1] = NULL;
 546                         }
 547                 }
 548
 549                 if (env)
 550                 {
 551                         blobmsg_for_each_attr(cur, env, rem)
 552                         {
 553                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 554                                         continue;
 555
 556                                 setenv(blobmsg_name(cur), blobmsg_data(cur), 1);
 557                         }
 558                 }
 559
 560                 if (execv(cmd, args))
 561                         return rpc_errno_status();
 562
 563         default:
 564                 memset(c, 0, sizeof(*c));
 565
 566                 ustream_declare(c->opipe, opipe[0], exec_opipe);
 567                 ustream_declare(c->epipe, epipe[0], exec_epipe);
 568
 569                 c->process.pid = pid;
 570                 c->process.cb = rpc_file_exec_process_cb;
 571                 uloop_process_add(&c->process);
 572
 573                 c->timeout.cb = rpc_file_exec_timeout_cb;
 574                 uloop_timeout_set(&c->timeout, RPC_FILE_MAX_RUNTIME);
 575
 576                 close(opipe[1]);
 577                 close(epipe[1]);
 578
 579                 c->context = ctx;
 580                 ubus_defer_request(ctx, req, &c->request);
 581         }
 582
 583         return UBUS_STATUS_OK;
 584 }
 585
 586 static int
 587 rpc_file_exec(struct ubus_context *ctx, struct ubus_object *obj,
 588               struct ubus_request_data *req, const char *method,
 589               struct blob_attr *msg)
 590 {
 591         struct blob_attr *tb[__RPC_E_MAX];
 592
 593         blobmsg_parse(rpc_exec_policy, __RPC_E_MAX, tb,
 594                       blob_data(msg), blob_len(msg));
 595
 596         if (!tb[RPC_E_CMD])
 597                 return UBUS_STATUS_INVALID_ARGUMENT;
 598
 599         return rpc_file_exec_run(blobmsg_data(tb[RPC_E_CMD]),
 600                                               tb[RPC_E_PARM], tb[RPC_E_ENV], ctx, req);
 601 }
 602
 603
 604 static int
 605 rpc_file_api_init(const struct rpc_daemon_ops *o, struct ubus_context *ctx)
 606 {
 607         static const struct ubus_method file_methods[] = {
 608                 UBUS_METHOD("read",    rpc_file_read,  rpc_file_r_policy),
 609                 UBUS_METHOD("write",   rpc_file_write, rpc_file_rw_policy),
 610                 UBUS_METHOD("list",    rpc_file_list,  rpc_file_r_policy),
 611                 UBUS_METHOD("stat",    rpc_file_stat,  rpc_file_r_policy),
 612                 UBUS_METHOD("exec",    rpc_file_exec,  rpc_exec_policy),
 613         };
 614
 615         static struct ubus_object_type file_type =
 616                 UBUS_OBJECT_TYPE("luci-rpc-file", file_methods);
 617
 618         static struct ubus_object obj = {
 619                 .name = "file",
 620                 .type = &file_type,
 621                 .methods = file_methods,
 622                 .n_methods = ARRAY_SIZE(file_methods),
 623         };
 624
 625         return ubus_add_object(ctx, &obj);
 626 }
 627
 628 struct rpc_plugin rpc_plugin = {
 629         .init = rpc_file_api_init
 630 };