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         rv = UBUS_STATUS_OK;
 203
 204 out:
 205         close(fd);
 206         return rv;
 207 }
 208
 209 static int
 210 rpc_file_write(struct ubus_context *ctx, struct ubus_object *obj,
 211                struct ubus_request_data *req, const char *method,
 212                struct blob_attr *msg)
 213 {
 214         int fd;
 215         struct blob_attr *tb[__RPC_F_RW_MAX];
 216
 217         blobmsg_parse(rpc_file_rw_policy, __RPC_F_RW_MAX, tb,
 218                       blob_data(msg), blob_len(msg));
 219
 220         if (!tb[RPC_F_RW_PATH] || !tb[RPC_F_RW_DATA])
 221                 return UBUS_STATUS_INVALID_ARGUMENT;
 222
 223         if ((fd = open(blobmsg_data(tb[RPC_F_RW_PATH]), O_CREAT | O_TRUNC | O_WRONLY)) < 0)
 224                 return rpc_errno_status();
 225
 226         if (write(fd, blobmsg_data(tb[RPC_F_RW_DATA]), blobmsg_data_len(tb[RPC_F_RW_DATA])) < 0)
 227                 return rpc_errno_status();
 228
 229         if (fsync(fd) < 0)
 230                 return rpc_errno_status();
 231
 232         close(fd);
 233         sync();
 234
 235         return 0;
 236 }
 237
 238 static int
 239 rpc_file_list(struct ubus_context *ctx, struct ubus_object *obj,
 240               struct ubus_request_data *req, const char *method,
 241               struct blob_attr *msg)
 242 {
 243         DIR *fd;
 244         void *c, *d;
 245         char *path;
 246         struct stat s;
 247         struct dirent *e;
 248
 249         if (!rpc_check_path(msg, &path, &s))
 250                 return rpc_errno_status();
 251
 252         if ((fd = opendir(path)) == NULL)
 253                 return rpc_errno_status();
 254
 255         blob_buf_init(&buf, 0);
 256         c = blobmsg_open_array(&buf, "entries");
 257
 258         while ((e = readdir(fd)) != NULL)
 259         {
 260                 if (!strcmp(e->d_name, ".") || !strcmp(e->d_name, ".."))
 261                         continue;
 262
 263                 d = blobmsg_open_table(&buf, NULL);
 264                 blobmsg_add_string(&buf, "name", e->d_name);
 265                 blobmsg_add_string(&buf, "type", d_types[e->d_type]);
 266                 blobmsg_close_table(&buf, d);
 267         }
 268
 269         blobmsg_close_array(&buf, c);
 270         ubus_send_reply(ctx, req, buf.head);
 271
 272         return 0;
 273 }
 274
 275 static int
 276 rpc_file_stat(struct ubus_context *ctx, struct ubus_object *obj,
 277               struct ubus_request_data *req, const char *method,
 278               struct blob_attr *msg)
 279 {
 280         int type;
 281         char *path;
 282         struct stat s;
 283
 284         if (!rpc_check_path(msg, &path, &s))
 285                 return rpc_errno_status();
 286
 287         blob_buf_init(&buf, 0);
 288
 289         type = S_ISREG(s.st_mode) ? DT_REG :
 290                 S_ISDIR(s.st_mode) ? DT_DIR :
 291                  S_ISCHR(s.st_mode) ? DT_CHR :
 292                   S_ISBLK(s.st_mode) ? DT_BLK :
 293                    S_ISFIFO(s.st_mode) ? DT_FIFO :
 294                     S_ISLNK(s.st_mode) ? DT_LNK :
 295                      S_ISSOCK(s.st_mode) ? DT_SOCK :
 296                       DT_UNKNOWN;
 297
 298         blobmsg_add_string(&buf, "path", path);
 299         blobmsg_add_string(&buf, "type", d_types[type]);
 300         blobmsg_add_u32(&buf, "size",  s.st_size);
 301         blobmsg_add_u32(&buf, "mode",  s.st_mode);
 302         blobmsg_add_u32(&buf, "atime", s.st_atime);
 303         blobmsg_add_u32(&buf, "mtime", s.st_mtime);
 304         blobmsg_add_u32(&buf, "ctime", s.st_ctime);
 305         blobmsg_add_u32(&buf, "inode", s.st_ino);
 306         blobmsg_add_u32(&buf, "uid",   s.st_uid);
 307         blobmsg_add_u32(&buf, "gid",   s.st_gid);
 308
 309         ubus_send_reply(ctx, req, buf.head);
 310
 311         return 0;
 312 }
 313
 314 static const char *
 315 rpc_file_exec_lookup(const char *cmd)
 316 {
 317         struct stat s;
 318         int plen = 0, clen = strlen(cmd) + 1;
 319         char *search, *p;
 320         static char path[PATH_MAX];
 321
 322         if (!stat(cmd, &s) && S_ISREG(s.st_mode))
 323                 return cmd;
 324
 325         search = getenv("PATH");
 326
 327         if (!search)
 328                 search = "/bin:/usr/bin:/sbin:/usr/sbin";
 329
 330         p = search;
 331
 332         do
 333         {
 334                 if (*p != ':' && *p != '\0')
 335                         continue;
 336
 337                 plen = p - search;
 338
 339                 if ((plen + clen) >= sizeof(path))
 340                         continue;
 341
 342                 strncpy(path, search, plen);
 343                 sprintf(path + plen, "/%s", cmd);
 344
 345                 if (!stat(path, &s) && S_ISREG(s.st_mode))
 346                         return path;
 347
 348                 search = p + 1;
 349         }
 350         while (*p++);
 351
 352         return NULL;
 353 }
 354
 355
 356 static void
 357 rpc_ustream_to_blobmsg(struct ustream *s, const char *name)
 358 {
 359         int len;
 360         char *rbuf, *wbuf;
 361
 362         if ((len = ustream_pending_data(s, false)) > 0)
 363         {
 364                 wbuf = blobmsg_alloc_string_buffer(&buf, name, len + 1);
 365
 366                 if (!wbuf)
 367                         return;
 368
 369                 ustream_for_each_read_buffer(s, rbuf, len)
 370                 {
 371                         memcpy(wbuf, rbuf, len);
 372                         wbuf += len;
 373                 }
 374
 375                 *wbuf = 0;
 376                 blobmsg_add_string_buffer(&buf);
 377         }
 378 }
 379
 380 static void
 381 rpc_file_exec_reply(struct rpc_file_exec_context *c, int rv)
 382 {
 383         uloop_timeout_cancel(&c->timeout);
 384         uloop_process_delete(&c->process);
 385
 386         if (rv == UBUS_STATUS_OK)
 387         {
 388                 blob_buf_init(&buf, 0);
 389
 390                 blobmsg_add_u32(&buf, "code", WEXITSTATUS(c->stat));
 391
 392                 rpc_ustream_to_blobmsg(&c->opipe.stream, "stdout");
 393                 rpc_ustream_to_blobmsg(&c->epipe.stream, "stderr");
 394
 395                 ubus_send_reply(c->context, &c->request, buf.head);
 396         }
 397
 398         ubus_complete_deferred_request(c->context, &c->request, rv);
 399
 400         ustream_free(&c->opipe.stream);
 401         ustream_free(&c->epipe.stream);
 402
 403         close(c->opipe.fd.fd);
 404         close(c->epipe.fd.fd);
 405
 406         free(c);
 407 }
 408
 409 static void
 410 rpc_file_exec_timeout_cb(struct uloop_timeout *t)
 411 {
 412         struct rpc_file_exec_context *c =
 413                 container_of(t, struct rpc_file_exec_context, timeout);
 414
 415         kill(c->process.pid, SIGKILL);
 416         rpc_file_exec_reply(c, UBUS_STATUS_TIMEOUT);
 417 }
 418
 419 static void
 420 rpc_file_exec_process_cb(struct uloop_process *p, int stat)
 421 {
 422         struct rpc_file_exec_context *c =
 423                 container_of(p, struct rpc_file_exec_context, process);
 424
 425         c->stat = stat;
 426
 427         ustream_poll(&c->opipe.stream);
 428         ustream_poll(&c->epipe.stream);
 429 }
 430
 431 static void
 432 rpc_file_exec_opipe_read_cb(struct ustream *s, int bytes)
 433 {
 434         struct rpc_file_exec_context *c =
 435                 container_of(s, struct rpc_file_exec_context, opipe.stream);
 436
 437         if (ustream_read_buf_full(s))
 438                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 439 }
 440
 441 static void
 442 rpc_file_exec_epipe_read_cb(struct ustream *s, int bytes)
 443 {
 444         struct rpc_file_exec_context *c =
 445                 container_of(s, struct rpc_file_exec_context, epipe.stream);
 446
 447         if (ustream_read_buf_full(s))
 448                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 449 }
 450
 451 static void
 452 rpc_file_exec_opipe_state_cb(struct ustream *s)
 453 {
 454         struct rpc_file_exec_context *c =
 455                 container_of(s, struct rpc_file_exec_context, opipe.stream);
 456
 457         if (c->opipe.stream.eof && c->epipe.stream.eof)
 458                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 459 }
 460
 461 static void
 462 rpc_file_exec_epipe_state_cb(struct ustream *s)
 463 {
 464         struct rpc_file_exec_context *c =
 465                 container_of(s, struct rpc_file_exec_context, epipe.stream);
 466
 467         if (c->opipe.stream.eof && c->epipe.stream.eof)
 468                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 469 }
 470
 471 static int
 472 rpc_file_exec_run(const char *cmd,
 473                   const struct blob_attr *arg, const struct blob_attr *env,
 474                   struct ubus_context *ctx, struct ubus_request_data *req)
 475 {
 476         pid_t pid;
 477
 478         int opipe[2];
 479         int epipe[2];
 480
 481         int rem;
 482         struct blob_attr *cur;
 483
 484         char arglen;
 485         char **args;
 486
 487         struct rpc_file_exec_context *c;
 488
 489         cmd = rpc_file_exec_lookup(cmd);
 490
 491         if (!cmd)
 492                 return UBUS_STATUS_NOT_FOUND;
 493
 494         c = malloc(sizeof(*c));
 495
 496         if (!c)
 497                 return UBUS_STATUS_UNKNOWN_ERROR;
 498
 499         if (pipe(opipe) || pipe(epipe))
 500                 return rpc_errno_status();
 501
 502         switch ((pid = fork()))
 503         {
 504         case -1:
 505                 return rpc_errno_status();
 506
 507         case 0:
 508                 uloop_done();
 509
 510                 dup2(opipe[1], 1);
 511                 dup2(epipe[1], 2);
 512
 513                 close(0);
 514                 close(opipe[0]);
 515                 close(opipe[1]);
 516                 close(epipe[0]);
 517                 close(epipe[1]);
 518
 519                 arglen = 2;
 520                 args = malloc(sizeof(char *) * arglen);
 521
 522                 if (!args)
 523                         return UBUS_STATUS_UNKNOWN_ERROR;
 524
 525                 args[0] = (char *)cmd;
 526                 args[1] = NULL;
 527
 528                 if (arg)
 529                 {
 530                         blobmsg_for_each_attr(cur, arg, rem)
 531                         {
 532                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 533                                         continue;
 534
 535                                 arglen++;
 536
 537                                 if (!(args = realloc(args, sizeof(char *) * arglen)))
 538                                         return UBUS_STATUS_UNKNOWN_ERROR;
 539
 540                                 args[arglen-2] = blobmsg_data(cur);
 541                                 args[arglen-1] = NULL;
 542                         }
 543                 }
 544
 545                 if (env)
 546                 {
 547                         blobmsg_for_each_attr(cur, env, rem)
 548                         {
 549                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 550                                         continue;
 551
 552                                 setenv(blobmsg_name(cur), blobmsg_data(cur), 1);
 553                         }
 554                 }
 555
 556                 if (execv(cmd, args))
 557                         return rpc_errno_status();
 558
 559         default:
 560                 memset(c, 0, sizeof(*c));
 561
 562                 ustream_declare(c->opipe, opipe[0], exec_opipe);
 563                 ustream_declare(c->epipe, epipe[0], exec_epipe);
 564
 565                 c->process.pid = pid;
 566                 c->process.cb = rpc_file_exec_process_cb;
 567                 uloop_process_add(&c->process);
 568
 569                 c->timeout.cb = rpc_file_exec_timeout_cb;
 570                 uloop_timeout_set(&c->timeout, RPC_FILE_MAX_RUNTIME);
 571
 572                 close(opipe[1]);
 573                 close(epipe[1]);
 574
 575                 c->context = ctx;
 576                 ubus_defer_request(ctx, req, &c->request);
 577         }
 578
 579         return UBUS_STATUS_OK;
 580 }
 581
 582 static int
 583 rpc_file_exec(struct ubus_context *ctx, struct ubus_object *obj,
 584               struct ubus_request_data *req, const char *method,
 585               struct blob_attr *msg)
 586 {
 587         struct blob_attr *tb[__RPC_E_MAX];
 588
 589         blobmsg_parse(rpc_exec_policy, __RPC_E_MAX, tb,
 590                       blob_data(msg), blob_len(msg));
 591
 592         if (!tb[RPC_E_CMD])
 593                 return UBUS_STATUS_INVALID_ARGUMENT;
 594
 595         return rpc_file_exec_run(blobmsg_data(tb[RPC_E_CMD]),
 596                                               tb[RPC_E_PARM], tb[RPC_E_ENV], ctx, req);
 597 }
 598
 599
 600 static int
 601 rpc_file_api_init(const struct rpc_daemon_ops *o, struct ubus_context *ctx)
 602 {
 603         static const struct ubus_method file_methods[] = {
 604                 UBUS_METHOD("read",    rpc_file_read,  rpc_file_r_policy),
 605                 UBUS_METHOD("write",   rpc_file_write, rpc_file_rw_policy),
 606                 UBUS_METHOD("list",    rpc_file_list,  rpc_file_r_policy),
 607                 UBUS_METHOD("stat",    rpc_file_stat,  rpc_file_r_policy),
 608                 UBUS_METHOD("exec",    rpc_file_exec,  rpc_exec_policy),
 609         };
 610
 611         static struct ubus_object_type file_type =
 612                 UBUS_OBJECT_TYPE("luci-rpc-file", file_methods);
 613
 614         static struct ubus_object obj = {
 615                 .name = "file",
 616                 .type = &file_type,
 617                 .methods = file_methods,
 618                 .n_methods = ARRAY_SIZE(file_methods),
 619         };
 620
 621         return ubus_add_object(ctx, &obj);
 622 }
 623
 624 struct rpc_plugin rpc_plugin = {
 625         .init = rpc_file_api_init
 626 };