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         closedir(fd);
 271
 272         blobmsg_close_array(&buf, c);
 273         ubus_send_reply(ctx, req, buf.head);
 274         blob_buf_free(&buf);
 275
 276         return 0;
 277 }
 278
 279 static int
 280 rpc_file_stat(struct ubus_context *ctx, struct ubus_object *obj,
 281               struct ubus_request_data *req, const char *method,
 282               struct blob_attr *msg)
 283 {
 284         int type;
 285         char *path;
 286         struct stat s;
 287
 288         if (!rpc_check_path(msg, &path, &s))
 289                 return rpc_errno_status();
 290
 291         blob_buf_init(&buf, 0);
 292
 293         type = S_ISREG(s.st_mode) ? DT_REG :
 294                 S_ISDIR(s.st_mode) ? DT_DIR :
 295                  S_ISCHR(s.st_mode) ? DT_CHR :
 296                   S_ISBLK(s.st_mode) ? DT_BLK :
 297                    S_ISFIFO(s.st_mode) ? DT_FIFO :
 298                     S_ISLNK(s.st_mode) ? DT_LNK :
 299                      S_ISSOCK(s.st_mode) ? DT_SOCK :
 300                       DT_UNKNOWN;
 301
 302         blobmsg_add_string(&buf, "path", path);
 303         blobmsg_add_string(&buf, "type", d_types[type]);
 304         blobmsg_add_u32(&buf, "size",  s.st_size);
 305         blobmsg_add_u32(&buf, "mode",  s.st_mode);
 306         blobmsg_add_u32(&buf, "atime", s.st_atime);
 307         blobmsg_add_u32(&buf, "mtime", s.st_mtime);
 308         blobmsg_add_u32(&buf, "ctime", s.st_ctime);
 309         blobmsg_add_u32(&buf, "inode", s.st_ino);
 310         blobmsg_add_u32(&buf, "uid",   s.st_uid);
 311         blobmsg_add_u32(&buf, "gid",   s.st_gid);
 312
 313         ubus_send_reply(ctx, req, buf.head);
 314         blob_buf_free(&buf);
 315
 316         return 0;
 317 }
 318
 319 static const char *
 320 rpc_file_exec_lookup(const char *cmd)
 321 {
 322         struct stat s;
 323         int plen = 0, clen = strlen(cmd) + 1;
 324         char *search, *p;
 325         static char path[PATH_MAX];
 326
 327         if (!stat(cmd, &s) && S_ISREG(s.st_mode))
 328                 return cmd;
 329
 330         search = getenv("PATH");
 331
 332         if (!search)
 333                 search = "/bin:/usr/bin:/sbin:/usr/sbin";
 334
 335         p = search;
 336
 337         do
 338         {
 339                 if (*p != ':' && *p != '\0')
 340                         continue;
 341
 342                 plen = p - search;
 343
 344                 if ((plen + clen) >= sizeof(path))
 345                         continue;
 346
 347                 strncpy(path, search, plen);
 348                 sprintf(path + plen, "/%s", cmd);
 349
 350                 if (!stat(path, &s) && S_ISREG(s.st_mode))
 351                         return path;
 352
 353                 search = p + 1;
 354         }
 355         while (*p++);
 356
 357         return NULL;
 358 }
 359
 360
 361 static void
 362 rpc_ustream_to_blobmsg(struct ustream *s, const char *name)
 363 {
 364         int len;
 365         char *rbuf, *wbuf;
 366
 367         if ((len = ustream_pending_data(s, false)) > 0)
 368         {
 369                 wbuf = blobmsg_alloc_string_buffer(&buf, name, len + 1);
 370
 371                 if (!wbuf)
 372                         return;
 373
 374                 ustream_for_each_read_buffer(s, rbuf, len)
 375                 {
 376                         memcpy(wbuf, rbuf, len);
 377                         wbuf += len;
 378                 }
 379
 380                 *wbuf = 0;
 381                 blobmsg_add_string_buffer(&buf);
 382         }
 383 }
 384
 385 static void
 386 rpc_file_exec_reply(struct rpc_file_exec_context *c, int rv)
 387 {
 388         uloop_timeout_cancel(&c->timeout);
 389         uloop_process_delete(&c->process);
 390
 391         if (rv == UBUS_STATUS_OK)
 392         {
 393                 blob_buf_init(&buf, 0);
 394
 395                 blobmsg_add_u32(&buf, "code", WEXITSTATUS(c->stat));
 396
 397                 rpc_ustream_to_blobmsg(&c->opipe.stream, "stdout");
 398                 rpc_ustream_to_blobmsg(&c->epipe.stream, "stderr");
 399
 400                 ubus_send_reply(c->context, &c->request, buf.head);
 401                 blob_buf_free(&buf);
 402         }
 403
 404         ubus_complete_deferred_request(c->context, &c->request, rv);
 405
 406         ustream_free(&c->opipe.stream);
 407         ustream_free(&c->epipe.stream);
 408
 409         close(c->opipe.fd.fd);
 410         close(c->epipe.fd.fd);
 411
 412         free(c);
 413 }
 414
 415 static void
 416 rpc_file_exec_timeout_cb(struct uloop_timeout *t)
 417 {
 418         struct rpc_file_exec_context *c =
 419                 container_of(t, struct rpc_file_exec_context, timeout);
 420
 421         kill(c->process.pid, SIGKILL);
 422         rpc_file_exec_reply(c, UBUS_STATUS_TIMEOUT);
 423 }
 424
 425 static void
 426 rpc_file_exec_process_cb(struct uloop_process *p, int stat)
 427 {
 428         struct rpc_file_exec_context *c =
 429                 container_of(p, struct rpc_file_exec_context, process);
 430
 431         c->stat = stat;
 432
 433         ustream_poll(&c->opipe.stream);
 434         ustream_poll(&c->epipe.stream);
 435 }
 436
 437 static void
 438 rpc_file_exec_opipe_read_cb(struct ustream *s, int bytes)
 439 {
 440         struct rpc_file_exec_context *c =
 441                 container_of(s, struct rpc_file_exec_context, opipe.stream);
 442
 443         if (ustream_read_buf_full(s))
 444                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 445 }
 446
 447 static void
 448 rpc_file_exec_epipe_read_cb(struct ustream *s, int bytes)
 449 {
 450         struct rpc_file_exec_context *c =
 451                 container_of(s, struct rpc_file_exec_context, epipe.stream);
 452
 453         if (ustream_read_buf_full(s))
 454                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 455 }
 456
 457 static void
 458 rpc_file_exec_opipe_state_cb(struct ustream *s)
 459 {
 460         struct rpc_file_exec_context *c =
 461                 container_of(s, struct rpc_file_exec_context, opipe.stream);
 462
 463         if (c->opipe.stream.eof && c->epipe.stream.eof)
 464                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 465 }
 466
 467 static void
 468 rpc_file_exec_epipe_state_cb(struct ustream *s)
 469 {
 470         struct rpc_file_exec_context *c =
 471                 container_of(s, struct rpc_file_exec_context, epipe.stream);
 472
 473         if (c->opipe.stream.eof && c->epipe.stream.eof)
 474                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 475 }
 476
 477 static int
 478 rpc_file_exec_run(const char *cmd,
 479                   const struct blob_attr *arg, const struct blob_attr *env,
 480                   struct ubus_context *ctx, struct ubus_request_data *req)
 481 {
 482         pid_t pid;
 483
 484         int opipe[2];
 485         int epipe[2];
 486
 487         int rem;
 488         struct blob_attr *cur;
 489
 490         char arglen;
 491         char **args;
 492
 493         struct rpc_file_exec_context *c;
 494
 495         cmd = rpc_file_exec_lookup(cmd);
 496
 497         if (!cmd)
 498                 return UBUS_STATUS_NOT_FOUND;
 499
 500         c = malloc(sizeof(*c));
 501
 502         if (!c)
 503                 return UBUS_STATUS_UNKNOWN_ERROR;
 504
 505         if (pipe(opipe) || pipe(epipe))
 506                 return rpc_errno_status();
 507
 508         switch ((pid = fork()))
 509         {
 510         case -1:
 511                 return rpc_errno_status();
 512
 513         case 0:
 514                 uloop_done();
 515
 516                 dup2(opipe[1], 1);
 517                 dup2(epipe[1], 2);
 518
 519                 close(0);
 520                 close(opipe[0]);
 521                 close(opipe[1]);
 522                 close(epipe[0]);
 523                 close(epipe[1]);
 524
 525                 arglen = 2;
 526                 args = malloc(sizeof(char *) * arglen);
 527
 528                 if (!args)
 529                         return UBUS_STATUS_UNKNOWN_ERROR;
 530
 531                 args[0] = (char *)cmd;
 532                 args[1] = NULL;
 533
 534                 if (arg)
 535                 {
 536                         blobmsg_for_each_attr(cur, arg, rem)
 537                         {
 538                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 539                                         continue;
 540
 541                                 arglen++;
 542
 543                                 if (!(args = realloc(args, sizeof(char *) * arglen)))
 544                                         return UBUS_STATUS_UNKNOWN_ERROR;
 545
 546                                 args[arglen-2] = blobmsg_data(cur);
 547                                 args[arglen-1] = NULL;
 548                         }
 549                 }
 550
 551                 if (env)
 552                 {
 553                         blobmsg_for_each_attr(cur, env, rem)
 554                         {
 555                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 556                                         continue;
 557
 558                                 setenv(blobmsg_name(cur), blobmsg_data(cur), 1);
 559                         }
 560                 }
 561
 562                 if (execv(cmd, args))
 563                         return rpc_errno_status();
 564
 565         default:
 566                 memset(c, 0, sizeof(*c));
 567
 568                 ustream_declare(c->opipe, opipe[0], exec_opipe);
 569                 ustream_declare(c->epipe, epipe[0], exec_epipe);
 570
 571                 c->process.pid = pid;
 572                 c->process.cb = rpc_file_exec_process_cb;
 573                 uloop_process_add(&c->process);
 574
 575                 c->timeout.cb = rpc_file_exec_timeout_cb;
 576                 uloop_timeout_set(&c->timeout, RPC_FILE_MAX_RUNTIME);
 577
 578                 close(opipe[1]);
 579                 close(epipe[1]);
 580
 581                 c->context = ctx;
 582                 ubus_defer_request(ctx, req, &c->request);
 583         }
 584
 585         return UBUS_STATUS_OK;
 586 }
 587
 588 static int
 589 rpc_file_exec(struct ubus_context *ctx, struct ubus_object *obj,
 590               struct ubus_request_data *req, const char *method,
 591               struct blob_attr *msg)
 592 {
 593         struct blob_attr *tb[__RPC_E_MAX];
 594
 595         blobmsg_parse(rpc_exec_policy, __RPC_E_MAX, tb,
 596                       blob_data(msg), blob_len(msg));
 597
 598         if (!tb[RPC_E_CMD])
 599                 return UBUS_STATUS_INVALID_ARGUMENT;
 600
 601         return rpc_file_exec_run(blobmsg_data(tb[RPC_E_CMD]),
 602                                               tb[RPC_E_PARM], tb[RPC_E_ENV], ctx, req);
 603 }
 604
 605
 606 static int
 607 rpc_file_api_init(const struct rpc_daemon_ops *o, struct ubus_context *ctx)
 608 {
 609         static const struct ubus_method file_methods[] = {
 610                 UBUS_METHOD("read",    rpc_file_read,  rpc_file_r_policy),
 611                 UBUS_METHOD("write",   rpc_file_write, rpc_file_rw_policy),
 612                 UBUS_METHOD("list",    rpc_file_list,  rpc_file_r_policy),
 613                 UBUS_METHOD("stat",    rpc_file_stat,  rpc_file_r_policy),
 614                 UBUS_METHOD("exec",    rpc_file_exec,  rpc_exec_policy),
 615         };
 616
 617         static struct ubus_object_type file_type =
 618                 UBUS_OBJECT_TYPE("luci-rpc-file", file_methods);
 619
 620         static struct ubus_object obj = {
 621                 .name = "file",
 622                 .type = &file_type,
 623                 .methods = file_methods,
 624                 .n_methods = ARRAY_SIZE(file_methods),
 625         };
 626
 627         return ubus_add_object(ctx, &obj);
 628 }
 629
 630 struct rpc_plugin rpc_plugin = {
 631         .init = rpc_file_api_init
 632 };