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/md5.h>
  31 #include <libubox/ustream.h>
  32
  33 #include <rpcd/plugin.h>
  34
  35 /* limit of sys & proc files */
  36 #define RPC_FILE_MIN_SIZE               (128)
  37
  38 /* limit of regular files and command output data */
  39 #define RPC_FILE_MAX_SIZE               (4096 * 64)
  40 #define RPC_FILE_MAX_RUNTIME    (3 * 1000)
  41
  42 #define ustream_for_each_read_buffer(stream, ptr, len) \
  43         for (ptr = ustream_get_read_buf(stream, &len);     \
  44              ptr != NULL && len > 0;                       \
  45              ustream_consume(stream, len), ptr = ustream_get_read_buf(stream, &len))
  46
  47 #define ustream_declare(us, fd, name)                     \
  48         us.stream.string_data   = true;                       \
  49         us.stream.r.buffer_len  = 4096;                       \
  50         us.stream.r.max_buffers = RPC_FILE_MAX_SIZE / 4096;   \
  51         us.stream.notify_read   = rpc_file_##name##_read_cb;  \
  52         us.stream.notify_state  = rpc_file_##name##_state_cb; \
  53         ustream_fd_init(&us, fd);
  54
  55 struct rpc_file_exec_context {
  56         struct ubus_context *context;
  57         struct ubus_request_data request;
  58         struct uloop_timeout timeout;
  59         struct uloop_process process;
  60         struct ustream_fd opipe;
  61         struct ustream_fd epipe;
  62         int outlen;
  63         char *out;
  64         int errlen;
  65         char *err;
  66         int stat;
  67 };
  68
  69
  70 static struct blob_buf buf;
  71
  72 enum {
  73         RPC_F_R_PATH,
  74         __RPC_F_R_MAX,
  75 };
  76
  77 static const struct blobmsg_policy rpc_file_r_policy[__RPC_F_R_MAX] = {
  78         [RPC_F_R_PATH] = { .name = "path", .type = BLOBMSG_TYPE_STRING },
  79 };
  80
  81 enum {
  82         RPC_F_RW_PATH,
  83         RPC_F_RW_DATA,
  84         __RPC_F_RW_MAX,
  85 };
  86
  87 static const struct blobmsg_policy rpc_file_rw_policy[__RPC_F_RW_MAX] = {
  88         [RPC_F_RW_PATH] = { .name = "path", .type = BLOBMSG_TYPE_STRING },
  89         [RPC_F_RW_DATA] = { .name = "data", .type = BLOBMSG_TYPE_STRING },
  90 };
  91
  92 enum {
  93         RPC_E_CMD,
  94         RPC_E_PARM,
  95         RPC_E_ENV,
  96         __RPC_E_MAX,
  97 };
  98
  99 static const struct blobmsg_policy rpc_exec_policy[__RPC_E_MAX] = {
 100         [RPC_E_CMD]  = { .name = "command", .type = BLOBMSG_TYPE_STRING },
 101         [RPC_E_PARM] = { .name = "params",  .type = BLOBMSG_TYPE_ARRAY  },
 102         [RPC_E_ENV]  = { .name = "env",     .type = BLOBMSG_TYPE_TABLE  },
 103 };
 104
 105 static const char *d_types[] = {
 106         [DT_BLK]     = "block",
 107         [DT_CHR]     = "char",
 108         [DT_DIR]     = "directory",
 109         [DT_FIFO]    = "fifo",
 110         [DT_LNK]     = "symlink",
 111         [DT_REG]     = "file",
 112         [DT_SOCK]    = "socket",
 113         [DT_UNKNOWN] = "unknown",
 114 };
 115
 116
 117 static int
 118 rpc_errno_status(void)
 119 {
 120         switch (errno)
 121         {
 122         case EACCES:
 123                 return UBUS_STATUS_PERMISSION_DENIED;
 124
 125         case ENOTDIR:
 126                 return UBUS_STATUS_INVALID_ARGUMENT;
 127
 128         case ENOENT:
 129                 return UBUS_STATUS_NOT_FOUND;
 130
 131         case EINVAL:
 132                 return UBUS_STATUS_INVALID_ARGUMENT;
 133
 134         default:
 135                 return UBUS_STATUS_UNKNOWN_ERROR;
 136         }
 137 }
 138
 139 static struct blob_attr **
 140 rpc_check_path(struct blob_attr *msg, char **path, struct stat *s)
 141 {
 142         static struct blob_attr *tb[__RPC_F_R_MAX];
 143
 144         blobmsg_parse(rpc_file_r_policy, __RPC_F_R_MAX, tb, blob_data(msg), blob_len(msg));
 145
 146         if (!tb[RPC_F_R_PATH])
 147         {
 148                 errno = EINVAL;
 149                 return NULL;
 150         }
 151
 152         *path = blobmsg_data(tb[RPC_F_R_PATH]);
 153
 154         if (stat(*path, s))
 155                 return NULL;
 156
 157         return tb;
 158 }
 159
 160 static int
 161 rpc_file_read(struct ubus_context *ctx, struct ubus_object *obj,
 162               struct ubus_request_data *req, const char *method,
 163               struct blob_attr *msg)
 164 {
 165         int fd, rv, len;
 166         char *path;
 167         struct stat s;
 168         char *wbuf;
 169
 170         if (!rpc_check_path(msg, &path, &s))
 171                 return rpc_errno_status();
 172
 173         if (s.st_size >= RPC_FILE_MAX_SIZE)
 174                 return UBUS_STATUS_NOT_SUPPORTED;
 175
 176         if ((fd = open(path, O_RDONLY)) < 0)
 177                 return rpc_errno_status();
 178
 179         /* some sysfs files do not report a length */
 180         if (s.st_size == 0)
 181                 s.st_size = RPC_FILE_MIN_SIZE;
 182
 183         blob_buf_init(&buf, 0);
 184
 185         wbuf = blobmsg_alloc_string_buffer(&buf, "data", s.st_size + 1);
 186
 187         if (!wbuf)
 188         {
 189                 rv = UBUS_STATUS_UNKNOWN_ERROR;
 190                 goto out;
 191         }
 192
 193         if ((len = read(fd, wbuf, s.st_size)) <= 0)
 194         {
 195                 rv = UBUS_STATUS_NO_DATA;
 196                 goto out;
 197         }
 198
 199         *(wbuf + len) = 0;
 200         blobmsg_add_string_buffer(&buf);
 201
 202         ubus_send_reply(ctx, req, buf.head);
 203         blob_buf_free(&buf);
 204         rv = UBUS_STATUS_OK;
 205
 206 out:
 207         close(fd);
 208         return rv;
 209 }
 210
 211 static int
 212 rpc_file_write(struct ubus_context *ctx, struct ubus_object *obj,
 213                struct ubus_request_data *req, const char *method,
 214                struct blob_attr *msg)
 215 {
 216         int fd;
 217         struct blob_attr *tb[__RPC_F_RW_MAX];
 218
 219         blobmsg_parse(rpc_file_rw_policy, __RPC_F_RW_MAX, tb,
 220                       blob_data(msg), blob_len(msg));
 221
 222         if (!tb[RPC_F_RW_PATH] || !tb[RPC_F_RW_DATA])
 223                 return UBUS_STATUS_INVALID_ARGUMENT;
 224
 225         if ((fd = open(blobmsg_data(tb[RPC_F_RW_PATH]), O_CREAT | O_TRUNC | O_WRONLY, 0666)) < 0)
 226                 return rpc_errno_status();
 227
 228         if (write(fd, blobmsg_data(tb[RPC_F_RW_DATA]), blobmsg_data_len(tb[RPC_F_RW_DATA])) < 0)
 229                 return rpc_errno_status();
 230
 231         if (fsync(fd) < 0)
 232                 return rpc_errno_status();
 233
 234         close(fd);
 235         sync();
 236
 237         return 0;
 238 }
 239
 240 static int
 241 rpc_file_md5(struct ubus_context *ctx, struct ubus_object *obj,
 242              struct ubus_request_data *req, const char *method,
 243              struct blob_attr *msg)
 244 {
 245         int rv, i;
 246         char *path;
 247         struct stat s;
 248         uint8_t md5[16];
 249         char *wbuf;
 250
 251         if (!rpc_check_path(msg, &path, &s))
 252                 return rpc_errno_status();
 253
 254         if (!S_ISREG(s.st_mode))
 255                 return UBUS_STATUS_NOT_SUPPORTED;
 256
 257         if ((rv = md5sum(path, md5)) <= 0)
 258                 return rpc_errno_status();
 259
 260         blob_buf_init(&buf, 0);
 261         wbuf = blobmsg_alloc_string_buffer(&buf, "md5", 33);
 262
 263         for (i = 0; i < 16; i++)
 264                 sprintf(wbuf + (i * 2), "%02x", (uint8_t) md5[i]);
 265
 266         blobmsg_add_string_buffer(&buf);
 267         ubus_send_reply(ctx, req, buf.head);
 268         blob_buf_free(&buf);
 269
 270         return UBUS_STATUS_OK;
 271 }
 272
 273 static int
 274 rpc_file_list(struct ubus_context *ctx, struct ubus_object *obj,
 275               struct ubus_request_data *req, const char *method,
 276               struct blob_attr *msg)
 277 {
 278         DIR *fd;
 279         void *c, *d;
 280         char *path;
 281         struct stat s;
 282         struct dirent *e;
 283
 284         if (!rpc_check_path(msg, &path, &s))
 285                 return rpc_errno_status();
 286
 287         if ((fd = opendir(path)) == NULL)
 288                 return rpc_errno_status();
 289
 290         blob_buf_init(&buf, 0);
 291         c = blobmsg_open_array(&buf, "entries");
 292
 293         while ((e = readdir(fd)) != NULL)
 294         {
 295                 if (!strcmp(e->d_name, ".") || !strcmp(e->d_name, ".."))
 296                         continue;
 297
 298                 d = blobmsg_open_table(&buf, NULL);
 299                 blobmsg_add_string(&buf, "name", e->d_name);
 300                 blobmsg_add_string(&buf, "type", d_types[e->d_type]);
 301                 blobmsg_close_table(&buf, d);
 302         }
 303
 304         closedir(fd);
 305
 306         blobmsg_close_array(&buf, c);
 307         ubus_send_reply(ctx, req, buf.head);
 308         blob_buf_free(&buf);
 309
 310         return 0;
 311 }
 312
 313 static int
 314 rpc_file_stat(struct ubus_context *ctx, struct ubus_object *obj,
 315               struct ubus_request_data *req, const char *method,
 316               struct blob_attr *msg)
 317 {
 318         int type;
 319         char *path;
 320         struct stat s;
 321
 322         if (!rpc_check_path(msg, &path, &s))
 323                 return rpc_errno_status();
 324
 325         blob_buf_init(&buf, 0);
 326
 327         type = S_ISREG(s.st_mode) ? DT_REG :
 328                 S_ISDIR(s.st_mode) ? DT_DIR :
 329                  S_ISCHR(s.st_mode) ? DT_CHR :
 330                   S_ISBLK(s.st_mode) ? DT_BLK :
 331                    S_ISFIFO(s.st_mode) ? DT_FIFO :
 332                     S_ISLNK(s.st_mode) ? DT_LNK :
 333                      S_ISSOCK(s.st_mode) ? DT_SOCK :
 334                       DT_UNKNOWN;
 335
 336         blobmsg_add_string(&buf, "path", path);
 337         blobmsg_add_string(&buf, "type", d_types[type]);
 338         blobmsg_add_u32(&buf, "size",  s.st_size);
 339         blobmsg_add_u32(&buf, "mode",  s.st_mode);
 340         blobmsg_add_u32(&buf, "atime", s.st_atime);
 341         blobmsg_add_u32(&buf, "mtime", s.st_mtime);
 342         blobmsg_add_u32(&buf, "ctime", s.st_ctime);
 343         blobmsg_add_u32(&buf, "inode", s.st_ino);
 344         blobmsg_add_u32(&buf, "uid",   s.st_uid);
 345         blobmsg_add_u32(&buf, "gid",   s.st_gid);
 346
 347         ubus_send_reply(ctx, req, buf.head);
 348         blob_buf_free(&buf);
 349
 350         return 0;
 351 }
 352
 353 static const char *
 354 rpc_file_exec_lookup(const char *cmd)
 355 {
 356         struct stat s;
 357         int plen = 0, clen = strlen(cmd) + 1;
 358         char *search, *p;
 359         static char path[PATH_MAX];
 360
 361         if (!stat(cmd, &s) && S_ISREG(s.st_mode))
 362                 return cmd;
 363
 364         search = getenv("PATH");
 365
 366         if (!search)
 367                 search = "/bin:/usr/bin:/sbin:/usr/sbin";
 368
 369         p = search;
 370
 371         do
 372         {
 373                 if (*p != ':' && *p != '\0')
 374                         continue;
 375
 376                 plen = p - search;
 377
 378                 if ((plen + clen) >= sizeof(path))
 379                         continue;
 380
 381                 strncpy(path, search, plen);
 382                 sprintf(path + plen, "/%s", cmd);
 383
 384                 if (!stat(path, &s) && S_ISREG(s.st_mode))
 385                         return path;
 386
 387                 search = p + 1;
 388         }
 389         while (*p++);
 390
 391         return NULL;
 392 }
 393
 394
 395 static void
 396 rpc_ustream_to_blobmsg(struct ustream *s, const char *name)
 397 {
 398         int len;
 399         char *rbuf, *wbuf;
 400
 401         if ((len = ustream_pending_data(s, false)) > 0)
 402         {
 403                 wbuf = blobmsg_alloc_string_buffer(&buf, name, len + 1);
 404
 405                 if (!wbuf)
 406                         return;
 407
 408                 ustream_for_each_read_buffer(s, rbuf, len)
 409                 {
 410                         memcpy(wbuf, rbuf, len);
 411                         wbuf += len;
 412                 }
 413
 414                 *wbuf = 0;
 415                 blobmsg_add_string_buffer(&buf);
 416         }
 417 }
 418
 419 static void
 420 rpc_file_exec_reply(struct rpc_file_exec_context *c, int rv)
 421 {
 422         uloop_timeout_cancel(&c->timeout);
 423         uloop_process_delete(&c->process);
 424
 425         if (rv == UBUS_STATUS_OK)
 426         {
 427                 blob_buf_init(&buf, 0);
 428
 429                 blobmsg_add_u32(&buf, "code", WEXITSTATUS(c->stat));
 430
 431                 rpc_ustream_to_blobmsg(&c->opipe.stream, "stdout");
 432                 rpc_ustream_to_blobmsg(&c->epipe.stream, "stderr");
 433
 434                 ubus_send_reply(c->context, &c->request, buf.head);
 435                 blob_buf_free(&buf);
 436         }
 437
 438         ubus_complete_deferred_request(c->context, &c->request, rv);
 439
 440         ustream_free(&c->opipe.stream);
 441         ustream_free(&c->epipe.stream);
 442
 443         close(c->opipe.fd.fd);
 444         close(c->epipe.fd.fd);
 445
 446         free(c);
 447 }
 448
 449 static void
 450 rpc_file_exec_timeout_cb(struct uloop_timeout *t)
 451 {
 452         struct rpc_file_exec_context *c =
 453                 container_of(t, struct rpc_file_exec_context, timeout);
 454
 455         kill(c->process.pid, SIGKILL);
 456         rpc_file_exec_reply(c, UBUS_STATUS_TIMEOUT);
 457 }
 458
 459 static void
 460 rpc_file_exec_process_cb(struct uloop_process *p, int stat)
 461 {
 462         struct rpc_file_exec_context *c =
 463                 container_of(p, struct rpc_file_exec_context, process);
 464
 465         c->stat = stat;
 466
 467         ustream_poll(&c->opipe.stream);
 468         ustream_poll(&c->epipe.stream);
 469 }
 470
 471 static void
 472 rpc_file_exec_opipe_read_cb(struct ustream *s, int bytes)
 473 {
 474         struct rpc_file_exec_context *c =
 475                 container_of(s, struct rpc_file_exec_context, opipe.stream);
 476
 477         if (ustream_read_buf_full(s))
 478                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 479 }
 480
 481 static void
 482 rpc_file_exec_epipe_read_cb(struct ustream *s, int bytes)
 483 {
 484         struct rpc_file_exec_context *c =
 485                 container_of(s, struct rpc_file_exec_context, epipe.stream);
 486
 487         if (ustream_read_buf_full(s))
 488                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 489 }
 490
 491 static void
 492 rpc_file_exec_opipe_state_cb(struct ustream *s)
 493 {
 494         struct rpc_file_exec_context *c =
 495                 container_of(s, struct rpc_file_exec_context, opipe.stream);
 496
 497         if (c->opipe.stream.eof && c->epipe.stream.eof)
 498                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 499 }
 500
 501 static void
 502 rpc_file_exec_epipe_state_cb(struct ustream *s)
 503 {
 504         struct rpc_file_exec_context *c =
 505                 container_of(s, struct rpc_file_exec_context, epipe.stream);
 506
 507         if (c->opipe.stream.eof && c->epipe.stream.eof)
 508                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 509 }
 510
 511 static int
 512 rpc_file_exec_run(const char *cmd,
 513                   const struct blob_attr *arg, const struct blob_attr *env,
 514                   struct ubus_context *ctx, struct ubus_request_data *req)
 515 {
 516         pid_t pid;
 517
 518         int opipe[2];
 519         int epipe[2];
 520
 521         int rem;
 522         struct blob_attr *cur;
 523
 524         char arglen;
 525         char **args;
 526
 527         struct rpc_file_exec_context *c;
 528
 529         cmd = rpc_file_exec_lookup(cmd);
 530
 531         if (!cmd)
 532                 return UBUS_STATUS_NOT_FOUND;
 533
 534         c = malloc(sizeof(*c));
 535
 536         if (!c)
 537                 return UBUS_STATUS_UNKNOWN_ERROR;
 538
 539         if (pipe(opipe) || pipe(epipe))
 540                 return rpc_errno_status();
 541
 542         switch ((pid = fork()))
 543         {
 544         case -1:
 545                 return rpc_errno_status();
 546
 547         case 0:
 548                 uloop_done();
 549
 550                 dup2(opipe[1], 1);
 551                 dup2(epipe[1], 2);
 552
 553                 close(0);
 554                 close(opipe[0]);
 555                 close(opipe[1]);
 556                 close(epipe[0]);
 557                 close(epipe[1]);
 558
 559                 arglen = 2;
 560                 args = malloc(sizeof(char *) * arglen);
 561
 562                 if (!args)
 563                         return UBUS_STATUS_UNKNOWN_ERROR;
 564
 565                 args[0] = (char *)cmd;
 566                 args[1] = NULL;
 567
 568                 if (arg)
 569                 {
 570                         blobmsg_for_each_attr(cur, arg, rem)
 571                         {
 572                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 573                                         continue;
 574
 575                                 arglen++;
 576
 577                                 if (!(args = realloc(args, sizeof(char *) * arglen)))
 578                                         return UBUS_STATUS_UNKNOWN_ERROR;
 579
 580                                 args[arglen-2] = blobmsg_data(cur);
 581                                 args[arglen-1] = NULL;
 582                         }
 583                 }
 584
 585                 if (env)
 586                 {
 587                         blobmsg_for_each_attr(cur, env, rem)
 588                         {
 589                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 590                                         continue;
 591
 592                                 setenv(blobmsg_name(cur), blobmsg_data(cur), 1);
 593                         }
 594                 }
 595
 596                 if (execv(cmd, args))
 597                         return rpc_errno_status();
 598
 599         default:
 600                 memset(c, 0, sizeof(*c));
 601
 602                 ustream_declare(c->opipe, opipe[0], exec_opipe);
 603                 ustream_declare(c->epipe, epipe[0], exec_epipe);
 604
 605                 c->process.pid = pid;
 606                 c->process.cb = rpc_file_exec_process_cb;
 607                 uloop_process_add(&c->process);
 608
 609                 c->timeout.cb = rpc_file_exec_timeout_cb;
 610                 uloop_timeout_set(&c->timeout, RPC_FILE_MAX_RUNTIME);
 611
 612                 close(opipe[1]);
 613                 close(epipe[1]);
 614
 615                 c->context = ctx;
 616                 ubus_defer_request(ctx, req, &c->request);
 617         }
 618
 619         return UBUS_STATUS_OK;
 620 }
 621
 622 static int
 623 rpc_file_exec(struct ubus_context *ctx, struct ubus_object *obj,
 624               struct ubus_request_data *req, const char *method,
 625               struct blob_attr *msg)
 626 {
 627         struct blob_attr *tb[__RPC_E_MAX];
 628
 629         blobmsg_parse(rpc_exec_policy, __RPC_E_MAX, tb,
 630                       blob_data(msg), blob_len(msg));
 631
 632         if (!tb[RPC_E_CMD])
 633                 return UBUS_STATUS_INVALID_ARGUMENT;
 634
 635         return rpc_file_exec_run(blobmsg_data(tb[RPC_E_CMD]),
 636                                               tb[RPC_E_PARM], tb[RPC_E_ENV], ctx, req);
 637 }
 638
 639
 640 static int
 641 rpc_file_api_init(const struct rpc_daemon_ops *o, struct ubus_context *ctx)
 642 {
 643         static const struct ubus_method file_methods[] = {
 644                 UBUS_METHOD("read",    rpc_file_read,  rpc_file_r_policy),
 645                 UBUS_METHOD("write",   rpc_file_write, rpc_file_rw_policy),
 646                 UBUS_METHOD("list",    rpc_file_list,  rpc_file_r_policy),
 647                 UBUS_METHOD("stat",    rpc_file_stat,  rpc_file_r_policy),
 648                 UBUS_METHOD("md5",     rpc_file_md5,   rpc_file_r_policy),
 649                 UBUS_METHOD("exec",    rpc_file_exec,  rpc_exec_policy),
 650         };
 651
 652         static struct ubus_object_type file_type =
 653                 UBUS_OBJECT_TYPE("luci-rpc-file", file_methods);
 654
 655         static struct ubus_object obj = {
 656                 .name = "file",
 657                 .type = &file_type,
 658                 .methods = file_methods,
 659                 .n_methods = ARRAY_SIZE(file_methods),
 660         };
 661
 662         return ubus_add_object(ctx, &obj);
 663 }
 664
 665 struct rpc_plugin rpc_plugin = {
 666         .init = rpc_file_api_init
 667 };