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