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_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         struct blob_attr *tb[__RPC_F_MAX];
 207
 208         blobmsg_parse(rpc_file_policy, __RPC_F_MAX, tb,
 209                       blob_data(msg), blob_len(msg));
 210
 211         if (!tb[RPC_F_PATH] || !tb[RPC_F_DATA])
 212                 return UBUS_STATUS_INVALID_ARGUMENT;
 213
 214         if ((fd = open(blobmsg_data(tb[RPC_F_PATH]), O_CREAT | O_TRUNC | O_WRONLY)) < 0)
 215                 return rpc_errno_status();
 216
 217         write(fd, blobmsg_data(tb[RPC_F_DATA]), blobmsg_data_len(tb[RPC_F_DATA]));
 218         close(fd);
 219
 220         return 0;
 221 }
 222
 223 static int
 224 rpc_file_list(struct ubus_context *ctx, struct ubus_object *obj,
 225               struct ubus_request_data *req, const char *method,
 226               struct blob_attr *msg)
 227 {
 228         DIR *fd;
 229         void *c, *d;
 230         char *path;
 231         struct stat s;
 232         struct dirent *e;
 233
 234         if (!rpc_check_path(msg, &path, &s))
 235                 return rpc_errno_status();
 236
 237         if ((fd = opendir(path)) == NULL)
 238                 return rpc_errno_status();
 239
 240         blob_buf_init(&buf, 0);
 241         c = blobmsg_open_array(&buf, "entries");
 242
 243         while ((e = readdir(fd)) != NULL)
 244         {
 245                 if (!strcmp(e->d_name, ".") || !strcmp(e->d_name, ".."))
 246                         continue;
 247
 248                 d = blobmsg_open_table(&buf, NULL);
 249                 blobmsg_add_string(&buf, "name", e->d_name);
 250                 blobmsg_add_string(&buf, "type", d_types[e->d_type]);
 251                 blobmsg_close_table(&buf, d);
 252         }
 253
 254         blobmsg_close_array(&buf, c);
 255         ubus_send_reply(ctx, req, buf.head);
 256
 257         return 0;
 258 }
 259
 260 static int
 261 rpc_file_stat(struct ubus_context *ctx, struct ubus_object *obj,
 262               struct ubus_request_data *req, const char *method,
 263               struct blob_attr *msg)
 264 {
 265         int type;
 266         char *path;
 267         struct stat s;
 268
 269         if (!rpc_check_path(msg, &path, &s))
 270                 return rpc_errno_status();
 271
 272         blob_buf_init(&buf, 0);
 273
 274         type = S_ISREG(s.st_mode) ? DT_REG :
 275                 S_ISDIR(s.st_mode) ? DT_DIR :
 276                  S_ISCHR(s.st_mode) ? DT_CHR :
 277                   S_ISBLK(s.st_mode) ? DT_BLK :
 278                    S_ISFIFO(s.st_mode) ? DT_FIFO :
 279                     S_ISLNK(s.st_mode) ? DT_LNK :
 280                      S_ISSOCK(s.st_mode) ? DT_SOCK :
 281                       DT_UNKNOWN;
 282
 283         blobmsg_add_string(&buf, "path", path);
 284         blobmsg_add_string(&buf, "type", d_types[type]);
 285         blobmsg_add_u32(&buf, "size",  s.st_size);
 286         blobmsg_add_u32(&buf, "mode",  s.st_mode);
 287         blobmsg_add_u32(&buf, "atime", s.st_atime);
 288         blobmsg_add_u32(&buf, "mtime", s.st_mtime);
 289         blobmsg_add_u32(&buf, "ctime", s.st_ctime);
 290         blobmsg_add_u32(&buf, "inode", s.st_ino);
 291         blobmsg_add_u32(&buf, "uid",   s.st_uid);
 292         blobmsg_add_u32(&buf, "gid",   s.st_gid);
 293
 294         ubus_send_reply(ctx, req, buf.head);
 295
 296         return 0;
 297 }
 298
 299 static const char *
 300 rpc_file_exec_lookup(const char *cmd)
 301 {
 302         struct stat s;
 303         int plen = 0, clen = strlen(cmd) + 1;
 304         char *search, *p;
 305         static char path[PATH_MAX];
 306
 307         if (!stat(cmd, &s) && S_ISREG(s.st_mode))
 308                 return cmd;
 309
 310         search = getenv("PATH");
 311
 312         if (!search)
 313                 search = "/bin:/usr/bin:/sbin:/usr/sbin";
 314
 315         p = search;
 316
 317         do
 318         {
 319                 if (*p != ':' && *p != '\0')
 320                         continue;
 321
 322                 plen = p - search;
 323
 324                 if ((plen + clen) >= sizeof(path))
 325                         continue;
 326
 327                 strncpy(path, search, plen);
 328                 sprintf(path + plen, "/%s", cmd);
 329
 330                 if (!stat(path, &s) && S_ISREG(s.st_mode))
 331                         return path;
 332
 333                 search = p + 1;
 334         }
 335         while (*p++);
 336
 337         return NULL;
 338 }
 339
 340
 341 static void
 342 rpc_ustream_to_blobmsg(struct ustream *s, const char *name)
 343 {
 344         int len;
 345         char *rbuf, *wbuf;
 346
 347         if ((len = ustream_pending_data(s, false)) > 0)
 348         {
 349                 wbuf = blobmsg_alloc_string_buffer(&buf, name, len + 1);
 350
 351                 if (!wbuf)
 352                         return;
 353
 354                 ustream_for_each_read_buffer(s, rbuf, len)
 355                 {
 356                         memcpy(wbuf, rbuf, len);
 357                         wbuf += len;
 358                 }
 359
 360                 *wbuf = 0;
 361                 blobmsg_add_string_buffer(&buf);
 362         }
 363 }
 364
 365 static void
 366 rpc_file_exec_reply(struct rpc_file_exec_context *c, int rv)
 367 {
 368         uloop_timeout_cancel(&c->timeout);
 369         uloop_process_delete(&c->process);
 370
 371         if (rv == UBUS_STATUS_OK)
 372         {
 373                 blob_buf_init(&buf, 0);
 374
 375                 blobmsg_add_u32(&buf, "code", WEXITSTATUS(c->stat));
 376
 377                 rpc_ustream_to_blobmsg(&c->opipe.stream, "stdout");
 378                 rpc_ustream_to_blobmsg(&c->epipe.stream, "stderr");
 379
 380                 ubus_send_reply(c->context, &c->request, buf.head);
 381         }
 382
 383         ubus_complete_deferred_request(c->context, &c->request, rv);
 384
 385         ustream_free(&c->opipe.stream);
 386         ustream_free(&c->epipe.stream);
 387
 388         close(c->opipe.fd.fd);
 389         close(c->epipe.fd.fd);
 390
 391         free(c);
 392 }
 393
 394 static void
 395 rpc_file_exec_timeout_cb(struct uloop_timeout *t)
 396 {
 397         struct rpc_file_exec_context *c =
 398                 container_of(t, struct rpc_file_exec_context, timeout);
 399
 400         kill(c->process.pid, SIGKILL);
 401         rpc_file_exec_reply(c, UBUS_STATUS_TIMEOUT);
 402 }
 403
 404 static void
 405 rpc_file_exec_process_cb(struct uloop_process *p, int stat)
 406 {
 407         struct rpc_file_exec_context *c =
 408                 container_of(p, struct rpc_file_exec_context, process);
 409
 410         c->stat = stat;
 411
 412         ustream_poll(&c->opipe.stream);
 413         ustream_poll(&c->epipe.stream);
 414 }
 415
 416 static void
 417 rpc_file_exec_opipe_read_cb(struct ustream *s, int bytes)
 418 {
 419         struct rpc_file_exec_context *c =
 420                 container_of(s, struct rpc_file_exec_context, opipe.stream);
 421
 422         if (ustream_read_buf_full(s))
 423                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 424 }
 425
 426 static void
 427 rpc_file_exec_epipe_read_cb(struct ustream *s, int bytes)
 428 {
 429         struct rpc_file_exec_context *c =
 430                 container_of(s, struct rpc_file_exec_context, epipe.stream);
 431
 432         if (ustream_read_buf_full(s))
 433                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 434 }
 435
 436 static void
 437 rpc_file_exec_opipe_state_cb(struct ustream *s)
 438 {
 439         struct rpc_file_exec_context *c =
 440                 container_of(s, struct rpc_file_exec_context, opipe.stream);
 441
 442         if (c->opipe.stream.eof && c->epipe.stream.eof)
 443                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 444 }
 445
 446 static void
 447 rpc_file_exec_epipe_state_cb(struct ustream *s)
 448 {
 449         struct rpc_file_exec_context *c =
 450                 container_of(s, struct rpc_file_exec_context, epipe.stream);
 451
 452         if (c->opipe.stream.eof && c->epipe.stream.eof)
 453                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 454 }
 455
 456 static int
 457 rpc_file_exec_run(const char *cmd,
 458                   const struct blob_attr *arg, const struct blob_attr *env,
 459                   struct ubus_context *ctx, struct ubus_request_data *req)
 460 {
 461         pid_t pid;
 462
 463         int opipe[2];
 464         int epipe[2];
 465
 466         int rem;
 467         struct blob_attr *cur;
 468
 469         char arglen;
 470         char **args;
 471
 472         struct rpc_file_exec_context *c;
 473
 474         cmd = rpc_file_exec_lookup(cmd);
 475
 476         if (!cmd)
 477                 return UBUS_STATUS_NOT_FOUND;
 478
 479         c = malloc(sizeof(*c));
 480
 481         if (!c)
 482                 return UBUS_STATUS_UNKNOWN_ERROR;
 483
 484         if (pipe(opipe) || pipe(epipe))
 485                 return rpc_errno_status();
 486
 487         switch ((pid = fork()))
 488         {
 489         case -1:
 490                 return rpc_errno_status();
 491
 492         case 0:
 493                 uloop_done();
 494
 495                 dup2(opipe[1], 1);
 496                 dup2(epipe[1], 2);
 497
 498                 close(0);
 499                 close(opipe[0]);
 500                 close(opipe[1]);
 501                 close(epipe[0]);
 502                 close(epipe[1]);
 503
 504                 arglen = 2;
 505                 args = malloc(sizeof(char *) * arglen);
 506
 507                 if (!args)
 508                         return UBUS_STATUS_UNKNOWN_ERROR;
 509
 510                 args[0] = (char *)cmd;
 511                 args[1] = NULL;
 512
 513                 if (arg)
 514                 {
 515                         blobmsg_for_each_attr(cur, arg, rem)
 516                         {
 517                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 518                                         continue;
 519
 520                                 arglen++;
 521
 522                                 if (!(args = realloc(args, sizeof(char *) * arglen)))
 523                                         return UBUS_STATUS_UNKNOWN_ERROR;
 524
 525                                 args[arglen-2] = blobmsg_data(cur);
 526                                 args[arglen-1] = NULL;
 527                         }
 528                 }
 529
 530                 if (env)
 531                 {
 532                         blobmsg_for_each_attr(cur, env, rem)
 533                         {
 534                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 535                                         continue;
 536
 537                                 setenv(blobmsg_name(cur), blobmsg_data(cur), 1);
 538                         }
 539                 }
 540
 541                 if (execv(cmd, args))
 542                         return rpc_errno_status();
 543
 544         default:
 545                 memset(c, 0, sizeof(*c));
 546
 547                 ustream_declare(c->opipe, opipe[0], exec_opipe);
 548                 ustream_declare(c->epipe, epipe[0], exec_epipe);
 549
 550                 c->process.pid = pid;
 551                 c->process.cb = rpc_file_exec_process_cb;
 552                 uloop_process_add(&c->process);
 553
 554                 c->timeout.cb = rpc_file_exec_timeout_cb;
 555                 uloop_timeout_set(&c->timeout, RPC_FILE_MAX_RUNTIME);
 556
 557                 close(opipe[1]);
 558                 close(epipe[1]);
 559
 560                 c->context = ctx;
 561                 ubus_defer_request(ctx, req, &c->request);
 562         }
 563
 564         return UBUS_STATUS_OK;
 565 }
 566
 567 static int
 568 rpc_file_exec(struct ubus_context *ctx, struct ubus_object *obj,
 569               struct ubus_request_data *req, const char *method,
 570               struct blob_attr *msg)
 571 {
 572         struct blob_attr *tb[__RPC_E_MAX];
 573
 574         blobmsg_parse(rpc_exec_policy, __RPC_E_MAX, tb,
 575                       blob_data(msg), blob_len(msg));
 576
 577         if (!tb[RPC_E_CMD])
 578                 return UBUS_STATUS_INVALID_ARGUMENT;
 579
 580         return rpc_file_exec_run(blobmsg_data(tb[RPC_E_CMD]),
 581                                               tb[RPC_E_PARM], tb[RPC_E_ENV], ctx, req);
 582 }
 583
 584
 585 static int
 586 rpc_file_api_init(const struct rpc_daemon_ops *o, struct ubus_context *ctx)
 587 {
 588         static const struct ubus_method file_methods[] = {
 589                 UBUS_METHOD("read",    rpc_file_read,  rpc_file_policy),
 590                 UBUS_METHOD("write",   rpc_file_write, rpc_file_policy),
 591                 UBUS_METHOD("list",    rpc_file_list,  rpc_file_policy),
 592                 UBUS_METHOD("stat",    rpc_file_stat,  rpc_file_policy),
 593                 UBUS_METHOD("exec",    rpc_file_exec,  rpc_exec_policy),
 594         };
 595
 596         static struct ubus_object_type file_type =
 597                 UBUS_OBJECT_TYPE("luci-rpc-file", file_methods);
 598
 599         static struct ubus_object obj = {
 600                 .name = "file",
 601                 .type = &file_type,
 602                 .methods = file_methods,
 603                 .n_methods = ARRAY_SIZE(file_methods),
 604         };
 605
 606         return ubus_add_object(ctx, &obj);
 607 }
 608
 609 const struct rpc_plugin rpc_plugin = {
 610         .init = rpc_file_api_init
 611 };