file.c

   1 /*
   2  * luci-rpcd - LuCI UBUS RPC server
   3  *
   4  *   Copyright (C) 2013 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
  29 #include "file.h"
  30
  31 static struct blob_buf buf;
  32
  33 enum {
  34         RPC_F_PATH,
  35         RPC_F_DATA,
  36         __RPC_F_MAX,
  37 };
  38
  39 static const struct blobmsg_policy rpc_file_policy[__RPC_F_MAX] = {
  40         [RPC_F_PATH] = { .name = "path", .type = BLOBMSG_TYPE_STRING },
  41         [RPC_F_DATA] = { .name = "data", .type = BLOBMSG_TYPE_STRING },
  42 };
  43
  44 enum {
  45         RPC_E_CMD,
  46         RPC_E_PARM,
  47         RPC_E_ENV,
  48         RPC_E_MODE,
  49         __RPC_E_MAX,
  50 };
  51
  52 static const struct blobmsg_policy rpc_exec_policy[__RPC_E_MAX] = {
  53         [RPC_E_CMD] = { .name = "command", .type = BLOBMSG_TYPE_STRING },
  54         [RPC_E_PARM] = { .name = "params",  .type = BLOBMSG_TYPE_ARRAY  },
  55         [RPC_E_ENV]  = { .name = "env",     .type = BLOBMSG_TYPE_TABLE  },
  56         [RPC_E_MODE] = { .name = "mode",    .type = BLOBMSG_TYPE_STRING },
  57 };
  58
  59 static const char *d_types[] = {
  60         [DT_BLK]     = "block",
  61         [DT_CHR]     = "char",
  62         [DT_DIR]     = "directory",
  63         [DT_FIFO]    = "fifo",
  64         [DT_LNK]     = "symlink",
  65         [DT_REG]     = "file",
  66         [DT_SOCK]    = "socket",
  67         [DT_UNKNOWN] = "unknown",
  68 };
  69
  70
  71 static int
  72 rpc_errno_status(void)
  73 {
  74         switch (errno)
  75         {
  76         case EACCES:
  77                 return UBUS_STATUS_PERMISSION_DENIED;
  78
  79         case ENOTDIR:
  80                 return UBUS_STATUS_INVALID_ARGUMENT;
  81
  82         case ENOENT:
  83                 return UBUS_STATUS_NOT_FOUND;
  84
  85         case EINVAL:
  86                 return UBUS_STATUS_INVALID_ARGUMENT;
  87
  88         default:
  89                 return UBUS_STATUS_UNKNOWN_ERROR;
  90         }
  91 }
  92
  93 static struct blob_attr **
  94 rpc_check_path(struct blob_attr *msg, char **path, struct stat *s)
  95 {
  96         static struct blob_attr *tb[__RPC_F_MAX];
  97
  98         blobmsg_parse(rpc_file_policy, __RPC_F_MAX, tb, blob_data(msg), blob_len(msg));
  99
 100         if (!tb[RPC_F_PATH])
 101         {
 102                 errno = EINVAL;
 103                 return NULL;
 104         }
 105
 106         *path = blobmsg_data(tb[RPC_F_PATH]);
 107
 108         if (stat(*path, s))
 109                 return NULL;
 110
 111         return tb;
 112 }
 113
 114 static int
 115 rpc_file_read(struct ubus_context *ctx, struct ubus_object *obj,
 116               struct ubus_request_data *req, const char *method,
 117               struct blob_attr *msg)
 118 {
 119         int fd, rv, len;
 120         char *path;
 121         struct stat s;
 122         char *wbuf;
 123
 124         if (!rpc_check_path(msg, &path, &s))
 125                 return rpc_errno_status();
 126
 127         if (s.st_size >= RPC_FILE_MAX_SIZE)
 128                 return UBUS_STATUS_NOT_SUPPORTED;
 129
 130         if ((fd = open(path, O_RDONLY)) < 0)
 131                 return rpc_errno_status();
 132
 133         /* some sysfs files do not report a length */
 134         if (s.st_size == 0)
 135                 s.st_size = RPC_FILE_MIN_SIZE;
 136
 137         blob_buf_init(&buf, 0);
 138
 139         wbuf = blobmsg_alloc_string_buffer(&buf, "data", s.st_size + 1);
 140
 141         if (!wbuf)
 142         {
 143                 rv = UBUS_STATUS_UNKNOWN_ERROR;
 144                 goto out;
 145         }
 146
 147         if ((len = read(fd, wbuf, s.st_size)) <= 0)
 148         {
 149                 rv = UBUS_STATUS_NO_DATA;
 150                 goto out;
 151         }
 152
 153         *(wbuf + len) = 0;
 154         blobmsg_add_string_buffer(&buf);
 155
 156         ubus_send_reply(ctx, req, buf.head);
 157         rv = UBUS_STATUS_OK;
 158
 159 out:
 160         close(fd);
 161         return rv;
 162 }
 163
 164 static int
 165 rpc_file_write(struct ubus_context *ctx, struct ubus_object *obj,
 166                struct ubus_request_data *req, const char *method,
 167                struct blob_attr *msg)
 168 {
 169         int fd;
 170         char *path;
 171         struct stat s;
 172         struct blob_attr **tb;
 173
 174         if (!(tb = rpc_check_path(msg, &path, &s)))
 175                 return rpc_errno_status();
 176
 177         if (!tb[RPC_F_DATA])
 178                 return UBUS_STATUS_INVALID_ARGUMENT;
 179
 180         if ((fd = open(path, O_WRONLY)) < 0)
 181                 return rpc_errno_status();
 182
 183         write(fd, blobmsg_data(tb[RPC_F_DATA]), blobmsg_data_len(tb[RPC_F_DATA]));
 184         close(fd);
 185
 186         return 0;
 187 }
 188
 189 static int
 190 rpc_file_list(struct ubus_context *ctx, struct ubus_object *obj,
 191               struct ubus_request_data *req, const char *method,
 192               struct blob_attr *msg)
 193 {
 194         DIR *fd;
 195         void *c, *d;
 196         char *path;
 197         struct stat s;
 198         struct dirent *e;
 199
 200         if (!rpc_check_path(msg, &path, &s))
 201                 return rpc_errno_status();
 202
 203         if ((fd = opendir(path)) == NULL)
 204                 return rpc_errno_status();
 205
 206         blob_buf_init(&buf, 0);
 207         c = blobmsg_open_array(&buf, "entries");
 208
 209         while ((e = readdir(fd)) != NULL)
 210         {
 211                 if (!strcmp(e->d_name, ".") || !strcmp(e->d_name, ".."))
 212                         continue;
 213
 214                 d = blobmsg_open_table(&buf, NULL);
 215                 blobmsg_add_string(&buf, "name", e->d_name);
 216                 blobmsg_add_string(&buf, "type", d_types[e->d_type]);
 217                 blobmsg_close_table(&buf, d);
 218         }
 219
 220         blobmsg_close_array(&buf, c);
 221         ubus_send_reply(ctx, req, buf.head);
 222
 223         return 0;
 224 }
 225
 226 static int
 227 rpc_file_stat(struct ubus_context *ctx, struct ubus_object *obj,
 228               struct ubus_request_data *req, const char *method,
 229               struct blob_attr *msg)
 230 {
 231         int type;
 232         char *path;
 233         struct stat s;
 234
 235         if (!rpc_check_path(msg, &path, &s))
 236                 return rpc_errno_status();
 237
 238         blob_buf_init(&buf, 0);
 239
 240         type = S_ISREG(s.st_mode) ? DT_REG :
 241                 S_ISDIR(s.st_mode) ? DT_DIR :
 242                  S_ISCHR(s.st_mode) ? DT_CHR :
 243                   S_ISBLK(s.st_mode) ? DT_BLK :
 244                    S_ISFIFO(s.st_mode) ? DT_FIFO :
 245                     S_ISLNK(s.st_mode) ? DT_LNK :
 246                      S_ISSOCK(s.st_mode) ? DT_SOCK :
 247                       DT_UNKNOWN;
 248
 249         blobmsg_add_string(&buf, "path", path);
 250         blobmsg_add_string(&buf, "type", d_types[type]);
 251         blobmsg_add_u32(&buf, "size",  s.st_size);
 252         blobmsg_add_u32(&buf, "mode",  s.st_mode);
 253         blobmsg_add_u32(&buf, "atime", s.st_atime);
 254         blobmsg_add_u32(&buf, "mtime", s.st_mtime);
 255         blobmsg_add_u32(&buf, "ctime", s.st_ctime);
 256         blobmsg_add_u32(&buf, "inode", s.st_ino);
 257         blobmsg_add_u32(&buf, "uid",   s.st_uid);
 258         blobmsg_add_u32(&buf, "gid",   s.st_gid);
 259
 260         ubus_send_reply(ctx, req, buf.head);
 261
 262         return 0;
 263 }
 264
 265 static const char *
 266 rpc_file_exec_lookup(const char *cmd)
 267 {
 268         struct stat s;
 269         int plen = 0, clen = strlen(cmd) + 1;
 270         char *search, *p;
 271         static char path[PATH_MAX];
 272
 273         if (!stat(cmd, &s) && S_ISREG(s.st_mode))
 274                 return cmd;
 275
 276         search = getenv("PATH");
 277
 278         if (!search)
 279                 search = "/bin:/usr/bin:/sbin:/usr/sbin";
 280
 281         p = search;
 282
 283         do
 284         {
 285                 if (*p != ':' && *p != '\0')
 286                         continue;
 287
 288                 plen = p - search;
 289
 290                 if ((plen + clen) >= sizeof(path))
 291                         continue;
 292
 293                 strncpy(path, search, plen);
 294                 sprintf(path + plen, "/%s", cmd);
 295
 296                 if (!stat(path, &s) && S_ISREG(s.st_mode))
 297                         return path;
 298
 299                 search = p + 1;
 300         }
 301         while (*p++);
 302
 303         return NULL;
 304 }
 305
 306
 307 static void
 308 rpc_ustream_to_blobmsg(struct ustream *s, const char *name)
 309 {
 310         int len;
 311         char *rbuf, *wbuf;
 312
 313         if ((len = ustream_pending_data(s, false)) > 0)
 314         {
 315                 wbuf = blobmsg_alloc_string_buffer(&buf, name, len + 1);
 316
 317                 if (!wbuf)
 318                         return;
 319
 320                 ustream_for_each_read_buffer(s, rbuf, len)
 321                 {
 322                         memcpy(wbuf, rbuf, len);
 323                         wbuf += len;
 324                 }
 325
 326                 *wbuf = 0;
 327                 blobmsg_add_string_buffer(&buf);
 328         }
 329 }
 330
 331 static void
 332 rpc_file_exec_reply(struct rpc_file_exec_context *c, int rv)
 333 {
 334         uloop_timeout_cancel(&c->timeout);
 335         uloop_process_delete(&c->process);
 336
 337         if (rv == UBUS_STATUS_OK)
 338         {
 339                 blob_buf_init(&buf, 0);
 340
 341                 blobmsg_add_u32(&buf, "code", WEXITSTATUS(c->stat));
 342
 343                 rpc_ustream_to_blobmsg(&c->opipe.stream, "stdout");
 344                 rpc_ustream_to_blobmsg(&c->epipe.stream, "stderr");
 345
 346                 ubus_send_reply(c->context, &c->request, buf.head);
 347         }
 348
 349         ubus_complete_deferred_request(c->context, &c->request, rv);
 350
 351         ustream_free(&c->opipe.stream);
 352         ustream_free(&c->epipe.stream);
 353
 354         close(c->opipe.fd.fd);
 355         close(c->epipe.fd.fd);
 356
 357         free(c);
 358 }
 359
 360 static void
 361 rpc_file_exec_timeout_cb(struct uloop_timeout *t)
 362 {
 363         struct rpc_file_exec_context *c =
 364                 container_of(t, struct rpc_file_exec_context, timeout);
 365
 366         kill(c->process.pid, SIGKILL);
 367         rpc_file_exec_reply(c, UBUS_STATUS_TIMEOUT);
 368 }
 369
 370 static void
 371 rpc_file_exec_process_cb(struct uloop_process *p, int stat)
 372 {
 373         struct rpc_file_exec_context *c =
 374                 container_of(p, struct rpc_file_exec_context, process);
 375
 376         c->stat = stat;
 377
 378         ustream_poll(&c->opipe.stream);
 379         ustream_poll(&c->epipe.stream);
 380 }
 381
 382 static void
 383 rpc_file_exec_opipe_read_cb(struct ustream *s, int bytes)
 384 {
 385         struct rpc_file_exec_context *c =
 386                 container_of(s, struct rpc_file_exec_context, opipe);
 387
 388         if (ustream_read_buf_full(s))
 389                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 390 }
 391
 392 static void
 393 rpc_file_exec_epipe_read_cb(struct ustream *s, int bytes)
 394 {
 395         struct rpc_file_exec_context *c =
 396                 container_of(s, struct rpc_file_exec_context, epipe);
 397
 398         if (ustream_read_buf_full(s))
 399                 rpc_file_exec_reply(c, UBUS_STATUS_NOT_SUPPORTED);
 400 }
 401
 402 static void
 403 rpc_file_exec_opipe_state_cb(struct ustream *s)
 404 {
 405         struct rpc_file_exec_context *c =
 406                 container_of(s, struct rpc_file_exec_context, opipe);
 407
 408         if (c->opipe.stream.eof && c->epipe.stream.eof)
 409                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 410 }
 411
 412 static void
 413 rpc_file_exec_epipe_state_cb(struct ustream *s)
 414 {
 415         struct rpc_file_exec_context *c =
 416                 container_of(s, struct rpc_file_exec_context, epipe);
 417
 418         if (c->opipe.stream.eof && c->epipe.stream.eof)
 419                 rpc_file_exec_reply(c, UBUS_STATUS_OK);
 420 }
 421
 422 static int
 423 rpc_file_exec_run(const char *cmd,
 424                               const struct blob_attr *arg, const struct blob_attr *env,
 425                   struct ubus_context *ctx, struct ubus_request_data *req)
 426 {
 427         pid_t pid;
 428
 429         int opipe[2];
 430         int epipe[2];
 431
 432         int rem;
 433         struct blob_attr *cur;
 434
 435         char arglen;
 436         char **args;
 437
 438         struct rpc_file_exec_context *c;
 439
 440         cmd = rpc_file_exec_lookup(cmd);
 441
 442         if (!cmd)
 443                 return UBUS_STATUS_NOT_FOUND;
 444
 445         c = malloc(sizeof(*c));
 446
 447         if (!c)
 448                 return UBUS_STATUS_UNKNOWN_ERROR;
 449
 450         if (pipe(opipe) || pipe(epipe))
 451                 return rpc_errno_status();
 452
 453         switch ((pid = fork()))
 454         {
 455         case -1:
 456                 return rpc_errno_status();
 457
 458         case 0:
 459                 uloop_done();
 460
 461                 dup2(opipe[1], 1);
 462                 dup2(epipe[1], 2);
 463
 464                 close(0);
 465                 close(opipe[0]);
 466                 close(opipe[1]);
 467                 close(epipe[0]);
 468                 close(epipe[1]);
 469
 470                 arglen = 2;
 471                 args = malloc(sizeof(char *) * arglen);
 472
 473                 if (!args)
 474                         return UBUS_STATUS_UNKNOWN_ERROR;
 475
 476                 args[0] = (char *)cmd;
 477                 args[1] = NULL;
 478
 479                 if (arg)
 480                 {
 481                         blobmsg_for_each_attr(cur, arg, rem)
 482                         {
 483                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 484                                         continue;
 485
 486                                 arglen++;
 487
 488                                 if (!(args = realloc(args, sizeof(char *) * arglen)))
 489                                         return UBUS_STATUS_UNKNOWN_ERROR;
 490
 491                                 args[arglen-2] = blobmsg_data(cur);
 492                                 args[arglen-1] = NULL;
 493                         }
 494                 }
 495
 496                 if (env)
 497                 {
 498                         blobmsg_for_each_attr(cur, env, rem)
 499                         {
 500                                 if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING)
 501                                         continue;
 502
 503                                 setenv(blobmsg_name(cur), blobmsg_data(cur), 1);
 504                         }
 505                 }
 506
 507                 if (execv(cmd, args))
 508                         return rpc_errno_status();
 509
 510         default:
 511                 memset(c, 0, sizeof(*c));
 512
 513                 ustream_declare(c->opipe, opipe[0], exec_opipe);
 514                 ustream_declare(c->epipe, epipe[0], exec_epipe);
 515
 516                 c->process.pid = pid;
 517                 c->process.cb = rpc_file_exec_process_cb;
 518                 uloop_process_add(&c->process);
 519
 520                 c->timeout.cb = rpc_file_exec_timeout_cb;
 521                 uloop_timeout_set(&c->timeout, RPC_FILE_MAX_RUNTIME);
 522
 523                 close(opipe[1]);
 524                 close(epipe[1]);
 525
 526                 c->context = ctx;
 527                 ubus_defer_request(ctx, req, &c->request);
 528         }
 529
 530         return UBUS_STATUS_OK;
 531 }
 532
 533 static int
 534 rpc_file_exec(struct ubus_context *ctx, struct ubus_object *obj,
 535               struct ubus_request_data *req, const char *method,
 536               struct blob_attr *msg)
 537 {
 538         struct blob_attr *tb[__RPC_E_MAX];
 539
 540         blobmsg_parse(rpc_exec_policy, __RPC_E_MAX, tb,
 541                       blob_data(msg), blob_len(msg));
 542
 543         if (!tb[RPC_E_CMD])
 544                 return UBUS_STATUS_INVALID_ARGUMENT;
 545
 546         return rpc_file_exec_run(blobmsg_data(tb[RPC_E_CMD]),
 547                                                  tb[RPC_E_PARM], tb[RPC_E_ENV], ctx, req);
 548 }
 549
 550
 551 int rpc_file_api_init(struct ubus_context *ctx)
 552 {
 553         static const struct ubus_method file_methods[] = {
 554                 UBUS_METHOD("read",    rpc_file_read,  rpc_file_policy),
 555                 UBUS_METHOD("write",   rpc_file_write, rpc_file_policy),
 556                 UBUS_METHOD("list",    rpc_file_list,  rpc_file_policy),
 557                 UBUS_METHOD("stat",    rpc_file_stat,  rpc_file_policy),
 558                 UBUS_METHOD("exec",    rpc_file_exec,  rpc_exec_policy),
 559         };
 560
 561         static struct ubus_object_type file_type =
 562                 UBUS_OBJECT_TYPE("luci-rpc-file", file_methods);
 563
 564         static struct ubus_object obj = {
 565                 .name = "file",
 566                 .type = &file_type,
 567                 .methods = file_methods,
 568                 .n_methods = ARRAY_SIZE(file_methods),
 569         };
 570
 571         return ubus_add_object(ctx, &obj);
 572 }