file.c

   1 /*
   2  * libuci - Library for the Unified Configuration Interface
   3  * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
   4  *
   5  * this program is free software; you can redistribute it and/or modify
   6  * it under the terms of the gnu lesser general public license version 2.1
   7  * as published by the free software foundation
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 /*
  16  * This file contains the code for parsing uci config files
  17  */
  18
  19 #include <sys/types.h>
  20 #include <sys/stat.h>
  21 #include <stdbool.h>
  22 #include <unistd.h>
  23 #include <fcntl.h>
  24 #include <stdio.h>
  25 #include <ctype.h>
  26
  27 #define LINEBUF 32
  28 #define LINEBUF_MAX     4096
  29
  30 static void uci_parse_error(struct uci_context *ctx, char *pos, char *reason)
  31 {
  32         struct uci_parse_context *pctx = ctx->pctx;
  33
  34         pctx->reason = reason;
  35         pctx->byte = pos - pctx->buf;
  36         UCI_THROW(ctx, UCI_ERR_PARSE);
  37 }
  38
  39 /*
  40  * Fetch a new line from the input stream and resize buffer if necessary
  41  */
  42 static void uci_getln(struct uci_context *ctx, int offset)
  43 {
  44         struct uci_parse_context *pctx = ctx->pctx;
  45         char *p;
  46         int ofs;
  47
  48         if (pctx->buf == NULL) {
  49                 pctx->buf = uci_malloc(ctx, LINEBUF);
  50                 pctx->bufsz = LINEBUF;
  51         }
  52
  53         ofs = offset;
  54         do {
  55                 p = &pctx->buf[ofs];
  56                 p[ofs] = 0;
  57
  58                 p = fgets(p, pctx->bufsz - ofs, pctx->file);
  59                 if (!p || !*p)
  60                         return;
  61
  62                 ofs += strlen(p);
  63                 if (pctx->buf[ofs - 1] == '\n') {
  64                         pctx->line++;
  65                         pctx->buf[ofs - 1] = 0;
  66                         return;
  67                 }
  68
  69                 if (pctx->bufsz > LINEBUF_MAX/2)
  70                         uci_parse_error(ctx, p, "line too long");
  71
  72                 pctx->bufsz *= 2;
  73                 pctx->buf = uci_realloc(ctx, pctx->buf, pctx->bufsz);
  74         } while (1);
  75 }
  76
  77 /*
  78  * Clean up all extra memory used by the parser and exporter
  79  */
  80 static void uci_file_cleanup(struct uci_context *ctx)
  81 {
  82         struct uci_parse_context *pctx;
  83
  84         if (ctx->buf) {
  85                 free(ctx->buf);
  86                 ctx->buf = NULL;
  87                 ctx->bufsz = 0;
  88         }
  89
  90         pctx = ctx->pctx;
  91         if (!pctx)
  92                 return;
  93
  94         ctx->pctx = NULL;
  95         if (pctx->package)
  96                 uci_free_package(pctx->package);
  97
  98         if (pctx->buf)
  99                 free(pctx->buf);
 100         if (pctx->file)
 101                 fclose(pctx->file);
 102
 103         free(pctx);
 104 }
 105
 106 /*
 107  * parse a character escaped by '\'
 108  * returns true if the escaped character is to be parsed
 109  * returns false if the escaped character is to be ignored
 110  */
 111 static inline bool parse_backslash(struct uci_context *ctx, char **str)
 112 {
 113         /* skip backslash */
 114         *str += 1;
 115
 116         /* undecoded backslash at the end of line, fetch the next line */
 117         if (!**str) {
 118                 *str += 1;
 119                 uci_getln(ctx, *str - ctx->pctx->buf);
 120                 return false;
 121         }
 122
 123         /* FIXME: decode escaped char, necessary? */
 124         return true;
 125 }
 126
 127 /*
 128  * move the string pointer forward until a non-whitespace character or
 129  * EOL is reached
 130  */
 131 static void skip_whitespace(struct uci_context *ctx, char **str)
 132 {
 133 restart:
 134         while (**str && isspace(**str))
 135                 *str += 1;
 136
 137         if (**str == '\\') {
 138                 if (!parse_backslash(ctx, str))
 139                         goto restart;
 140         }
 141 }
 142
 143 static inline void addc(char **dest, char **src)
 144 {
 145         **dest = **src;
 146         *dest += 1;
 147         *src += 1;
 148 }
 149
 150 /*
 151  * parse a double quoted string argument from the command line
 152  */
 153 static void parse_double_quote(struct uci_context *ctx, char **str, char **target)
 154 {
 155         char c;
 156
 157         /* skip quote character */
 158         *str += 1;
 159
 160         while ((c = **str)) {
 161                 switch(c) {
 162                 case '"':
 163                         **target = 0;
 164                         *str += 1;
 165                         return;
 166                 case '\\':
 167                         if (!parse_backslash(ctx, str))
 168                                 continue;
 169                         /* fall through */
 170                 default:
 171                         addc(target, str);
 172                         break;
 173                 }
 174         }
 175         uci_parse_error(ctx, *str, "unterminated \"");
 176 }
 177
 178 /*
 179  * parse a single quoted string argument from the command line
 180  */
 181 static void parse_single_quote(struct uci_context *ctx, char **str, char **target)
 182 {
 183         char c;
 184         /* skip quote character */
 185         *str += 1;
 186
 187         while ((c = **str)) {
 188                 switch(c) {
 189                 case '\'':
 190                         **target = 0;
 191                         *str += 1;
 192                         return;
 193                 default:
 194                         addc(target, str);
 195                 }
 196         }
 197         uci_parse_error(ctx, *str, "unterminated '");
 198 }
 199
 200 /*
 201  * parse a string from the command line and detect the quoting style
 202  */
 203 static void parse_str(struct uci_context *ctx, char **str, char **target)
 204 {
 205         do {
 206                 switch(**str) {
 207                 case '\'':
 208                         parse_single_quote(ctx, str, target);
 209                         break;
 210                 case '"':
 211                         parse_double_quote(ctx, str, target);
 212                         break;
 213                 case 0:
 214                         goto done;
 215                 case '\\':
 216                         if (!parse_backslash(ctx, str))
 217                                 continue;
 218                         /* fall through */
 219                 default:
 220                         addc(target, str);
 221                         break;
 222                 }
 223         } while (**str && !isspace(**str));
 224 done:
 225
 226         /*
 227          * if the string was unquoted and we've stopped at a whitespace
 228          * character, skip to the next one, because the whitespace will
 229          * be overwritten by a null byte here
 230          */
 231         if (**str)
 232                 *str += 1;
 233
 234         /* terminate the parsed string */
 235         **target = 0;
 236 }
 237
 238 /*
 239  * extract the next argument from the command line
 240  */
 241 static char *next_arg(struct uci_context *ctx, char **str, bool required)
 242 {
 243         char *val;
 244         char *ptr;
 245
 246         val = ptr = *str;
 247         skip_whitespace(ctx, str);
 248         parse_str(ctx, str, &ptr);
 249         if (required && !*val)
 250                 uci_parse_error(ctx, *str, "insufficient arguments");
 251
 252         return val;
 253 }
 254
 255 /*
 256  * verify that the end of the line or command is reached.
 257  * throw an error if extra arguments are given on the command line
 258  */
 259 static void assert_eol(struct uci_context *ctx, char **str)
 260 {
 261         char *tmp;
 262
 263         tmp = next_arg(ctx, str, false);
 264         if (tmp && *tmp)
 265                 uci_parse_error(ctx, *str, "too many arguments");
 266 }
 267
 268 /*
 269  * switch to a different config, either triggered by uci_load, or by a
 270  * 'package <...>' statement in the import file
 271  */
 272 static void uci_switch_config(struct uci_context *ctx)
 273 {
 274         struct uci_parse_context *pctx;
 275         struct uci_element *e;
 276         const char *name;
 277
 278         pctx = ctx->pctx;
 279         name = pctx->name;
 280
 281         /* add the last config to main config file list */
 282         if (pctx->package) {
 283                 uci_list_add(&ctx->root, &pctx->package->e.list);
 284
 285                 pctx->package = NULL;
 286                 pctx->section = NULL;
 287         }
 288
 289         if (!name)
 290                 return;
 291
 292         /*
 293          * if an older config under the same name exists, unload it
 294          * ignore errors here, e.g. if the config was not found
 295          */
 296         e = uci_lookup_list(ctx, &ctx->root, name);
 297         if (e)
 298                 UCI_THROW(ctx, UCI_ERR_DUPLICATE);
 299         pctx->package = uci_alloc_package(ctx, name);
 300 }
 301
 302 /*
 303  * parse the 'package' uci command (next config package)
 304  */
 305 static void uci_parse_package(struct uci_context *ctx, char **str, bool single)
 306 {
 307         char *name = NULL;
 308
 309         /* command string null-terminated by strtok */
 310         *str += strlen(*str) + 1;
 311
 312         name = next_arg(ctx, str, true);
 313         assert_eol(ctx, str);
 314         if (single)
 315                 return;
 316
 317         ctx->pctx->name = name;
 318         uci_switch_config(ctx);
 319 }
 320
 321 /*
 322  * parse the 'config' uci command (open a section)
 323  */
 324 static void uci_parse_config(struct uci_context *ctx, char **str)
 325 {
 326         char *name = NULL;
 327         char *type = NULL;
 328
 329         if (!ctx->pctx->package) {
 330                 if (!ctx->pctx->name)
 331                         uci_parse_error(ctx, *str, "attempting to import a file without a package name");
 332
 333                 uci_switch_config(ctx);
 334         }
 335
 336         /* command string null-terminated by strtok */
 337         *str += strlen(*str) + 1;
 338
 339         type = next_arg(ctx, str, true);
 340         name = next_arg(ctx, str, false);
 341         assert_eol(ctx, str);
 342         ctx->pctx->section = uci_alloc_section(ctx->pctx->package, type, name);
 343 }
 344
 345 /*
 346  * parse the 'option' uci command (open a value)
 347  */
 348 static void uci_parse_option(struct uci_context *ctx, char **str)
 349 {
 350         char *name = NULL;
 351         char *value = NULL;
 352
 353         if (!ctx->pctx->section)
 354                 uci_parse_error(ctx, *str, "option command found before the first section");
 355
 356         /* command string null-terminated by strtok */
 357         *str += strlen(*str) + 1;
 358
 359         name = next_arg(ctx, str, true);
 360         value = next_arg(ctx, str, true);
 361         assert_eol(ctx, str);
 362         uci_alloc_option(ctx->pctx->section, name, value);
 363 }
 364
 365
 366 /*
 367  * parse a complete input line, split up combined commands by ';'
 368  */
 369 static void uci_parse_line(struct uci_context *ctx, bool single)
 370 {
 371         struct uci_parse_context *pctx = ctx->pctx;
 372         char *word, *brk = NULL;
 373
 374         for (word = strtok_r(pctx->buf, ";", &brk);
 375                  word;
 376                  word = strtok_r(NULL, ";", &brk)) {
 377
 378                 char *pbrk = NULL;
 379                 word = strtok_r(word, " \t", &pbrk);
 380
 381                 switch(word[0]) {
 382                         case 'p':
 383                                 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
 384                                         uci_parse_package(ctx, &word, single);
 385                                 break;
 386                         case 'c':
 387                                 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
 388                                         uci_parse_config(ctx, &word);
 389                                 break;
 390                         case 'o':
 391                                 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
 392                                         uci_parse_option(ctx, &word);
 393                                 break;
 394                         default:
 395                                 uci_parse_error(ctx, word, "unterminated command");
 396                                 break;
 397                 }
 398         }
 399 }
 400
 401 /* max number of characters that escaping adds to the string */
 402 #define UCI_QUOTE_ESCAPE        "'\\''"
 403
 404 /*
 405  * escape an uci string for export
 406  */
 407 static char *uci_escape(struct uci_context *ctx, char *str)
 408 {
 409         char *s, *p;
 410         int pos = 0;
 411
 412         if (!ctx->buf) {
 413                 ctx->bufsz = LINEBUF;
 414                 ctx->buf = malloc(LINEBUF);
 415         }
 416
 417         s = str;
 418         p = strchr(str, '\'');
 419         if (!p)
 420                 return str;
 421
 422         do {
 423                 int len = p - s;
 424                 if (len > 0) {
 425                         if (p + sizeof(UCI_QUOTE_ESCAPE) - str >= ctx->bufsz) {
 426                                 ctx->bufsz *= 2;
 427                                 ctx->buf = realloc(ctx->buf, ctx->bufsz);
 428                                 if (!ctx->buf)
 429                                         UCI_THROW(ctx, UCI_ERR_MEM);
 430                         }
 431                         memcpy(&ctx->buf[pos], s, len);
 432                         pos += len;
 433                 }
 434                 strcpy(&ctx->buf[pos], UCI_QUOTE_ESCAPE);
 435                 pos += sizeof(UCI_QUOTE_ESCAPE);
 436                 s = p + 1;
 437         } while ((p = strchr(s, '\'')));
 438
 439         return ctx->buf;
 440 }
 441
 442
 443 /*
 444  * export a single config package to a file stream
 445  */
 446 static void uci_export_package(struct uci_package *p, FILE *stream, bool header)
 447 {
 448         struct uci_context *ctx = p->ctx;
 449         struct uci_element *s, *o;
 450
 451         if (header)
 452                 fprintf(stream, "package '%s'\n", uci_escape(ctx, p->e.name));
 453         uci_foreach_element(&p->sections, s) {
 454                 struct uci_section *sec = uci_to_section(s);
 455                 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, sec->type));
 456                 fprintf(stream, " '%s'\n", uci_escape(ctx, sec->e.name));
 457                 uci_foreach_element(&sec->options, o) {
 458                         struct uci_option *opt = uci_to_option(o);
 459                         fprintf(stream, "\toption '%s'", uci_escape(ctx, opt->e.name));
 460                         fprintf(stream, " '%s'\n", uci_escape(ctx, opt->value));
 461                 }
 462         }
 463         fprintf(stream, "\n");
 464 }
 465
 466 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header)
 467 {
 468         struct uci_element *e;
 469
 470         UCI_HANDLE_ERR(ctx);
 471         UCI_ASSERT(ctx, stream != NULL);
 472
 473         if (package)
 474                 uci_export_package(package, stream, header);
 475         else {
 476                 uci_foreach_element(&ctx->root, e) {
 477                         uci_export_package(uci_to_package(e), stream, header);
 478                 }
 479         }
 480
 481         return 0;
 482 }
 483
 484 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single)
 485 {
 486         struct uci_parse_context *pctx;
 487
 488         /* make sure no memory from previous parse attempts is leaked */
 489         uci_file_cleanup(ctx);
 490
 491         pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 492         ctx->pctx = pctx;
 493         pctx->file = stream;
 494
 495         /*
 496          * If 'name' was supplied, assume that the supplied stream does not contain
 497          * the appropriate 'package <name>' string to specify the config name
 498          * NB: the config file can still override the package name
 499          */
 500         if (name)
 501                 pctx->name = name;
 502
 503         while (!feof(pctx->file)) {
 504                 uci_getln(ctx, 0);
 505                 if (pctx->buf[0])
 506                         uci_parse_line(ctx, single);
 507         }
 508
 509         if (package)
 510                 *package = pctx->package;
 511
 512         pctx->name = NULL;
 513         uci_switch_config(ctx);
 514
 515         /* no error happened, we can get rid of the parser context now */
 516         uci_file_cleanup(ctx);
 517
 518         return 0;
 519 }
 520
 521 int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package)
 522 {
 523         struct stat statbuf;
 524         char *filename;
 525         bool confdir;
 526         FILE *file;
 527         int fd;
 528
 529         UCI_HANDLE_ERR(ctx);
 530         UCI_ASSERT(ctx, name != NULL);
 531
 532         switch (name[0]) {
 533         case '.':
 534                 if (name[1] != '/')
 535                         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 536                 /* fall through */
 537         case '/':
 538                 /* absolute/relative path outside of /etc/config */
 539                 filename = uci_strdup(ctx, name);
 540                 name = strrchr(name, '/') + 1;
 541                 confdir = false;
 542                 break;
 543         default:
 544                 filename = uci_malloc(ctx, strlen(name) + sizeof(UCI_CONFDIR) + 2);
 545                 sprintf(filename, UCI_CONFDIR "/%s", name);
 546                 confdir = true;
 547                 break;
 548         }
 549
 550         if ((stat(filename, &statbuf) < 0) ||
 551                 ((statbuf.st_mode &  S_IFMT) != S_IFREG)) {
 552                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 553         }
 554
 555         fd = open(filename, O_RDONLY);
 556         if (fd <= 0)
 557                 UCI_THROW(ctx, UCI_ERR_IO);
 558
 559         if (flock(fd, LOCK_SH) < 0)
 560                 UCI_THROW(ctx, UCI_ERR_IO);
 561
 562         file = fdopen(fd, "r");
 563         if (!file)
 564                 UCI_THROW(ctx, UCI_ERR_IO);
 565
 566         ctx->errno = 0;
 567         UCI_TRAP_SAVE(ctx, done);
 568         uci_import(ctx, file, name, package, true);
 569         UCI_TRAP_RESTORE(ctx);
 570
 571         if (*package) {
 572                 (*package)->path = filename;
 573                 (*package)->confdir = confdir;
 574         }
 575
 576 done:
 577         flock(fd, LOCK_UN);
 578         fclose(file);
 579         return ctx->errno;
 580 }
 581
 582 int uci_commit(struct uci_context *ctx, struct uci_package *p)
 583 {
 584         FILE *f = NULL;
 585         int fd = 0;
 586         int err = UCI_ERR_IO;
 587
 588         UCI_HANDLE_ERR(ctx);
 589         UCI_ASSERT(ctx, p != NULL);
 590         UCI_ASSERT(ctx, p->path != NULL);
 591
 592         fd = open(p->path, O_RDWR);
 593         if (fd < 0)
 594                 goto done;
 595
 596         if (flock(fd, LOCK_EX) < 0)
 597                 goto done;
 598
 599         ftruncate(fd, 0);
 600         f = fdopen(fd, "w");
 601         if (!f)
 602                 goto done;
 603
 604         UCI_TRAP_SAVE(ctx, done);
 605         uci_export(ctx, f, p, false);
 606         UCI_TRAP_RESTORE(ctx);
 607
 608 done:
 609         if (f)
 610                 fclose(f);
 611         else if (fd > 0)
 612                 close(fd);
 613
 614         if (ctx->errno)
 615                 UCI_THROW(ctx, ctx->errno);
 616         if (err)
 617                 UCI_THROW(ctx, UCI_ERR_IO);
 618         return 0;
 619 }
 620
 621
 622 /*
 623  * This function returns the filename by returning the string
 624  * after the last '/' character. By checking for a non-'\0'
 625  * character afterwards, directories are ignored (glob marks
 626  * those with a trailing '/'
 627  */
 628 static inline char *get_filename(char *path)
 629 {
 630         char *p;
 631
 632         p = strrchr(path, '/');
 633         p++;
 634         if (!*p)
 635                 return NULL;
 636         return p;
 637 }
 638
 639 char **uci_list_configs(struct uci_context *ctx)
 640 {
 641         char **configs;
 642         glob_t globbuf;
 643         int size, i;
 644         char *buf;
 645
 646         if (glob(UCI_CONFDIR "/*", GLOB_MARK, NULL, &globbuf) != 0)
 647                 return NULL;
 648
 649         size = sizeof(char *) * (globbuf.gl_pathc + 1);
 650         for(i = 0; i < globbuf.gl_pathc; i++) {
 651                 char *p;
 652
 653                 p = get_filename(globbuf.gl_pathv[i]);
 654                 if (!p)
 655                         continue;
 656
 657                 size += strlen(p) + 1;
 658         }
 659
 660         configs = malloc(size);
 661         if (!configs)
 662                 return NULL;
 663
 664         memset(configs, 0, size);
 665         buf = (char *) &configs[globbuf.gl_pathc + 1];
 666         for(i = 0; i < globbuf.gl_pathc; i++) {
 667                 char *p;
 668
 669                 p = get_filename(globbuf.gl_pathv[i]);
 670                 if (!p)
 671                         continue;
 672
 673                 configs[i] = buf;
 674                 strcpy(buf, p);
 675                 buf += strlen(buf) + 1;
 676         }
 677         return configs;
 678 }
 679
 680