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 /*
  31  * Fetch a new line from the input stream and resize buffer if necessary
  32  */
  33 static void uci_getln(struct uci_context *ctx, int offset)
  34 {
  35         struct uci_parse_context *pctx = ctx->pctx;
  36         char *p;
  37         int ofs;
  38
  39         if (pctx->buf == NULL) {
  40                 pctx->buf = uci_malloc(ctx, LINEBUF);
  41                 pctx->bufsz = LINEBUF;
  42         }
  43
  44         ofs = offset;
  45         do {
  46                 p = &pctx->buf[ofs];
  47                 p[ofs] = 0;
  48
  49                 p = fgets(p, pctx->bufsz - ofs, pctx->file);
  50                 if (!p || !*p)
  51                         return;
  52
  53                 ofs += strlen(p);
  54                 if (pctx->buf[ofs - 1] == '\n') {
  55                         pctx->line++;
  56                         pctx->buf[ofs - 1] = 0;
  57                         return;
  58                 }
  59
  60                 if (pctx->bufsz > LINEBUF_MAX/2) {
  61                         pctx->reason = "line too long";
  62                         pctx->byte = LINEBUF_MAX;
  63                         UCI_THROW(ctx, UCI_ERR_PARSE);
  64                 }
  65
  66                 pctx->bufsz *= 2;
  67                 pctx->buf = uci_realloc(ctx, pctx->buf, pctx->bufsz);
  68         } while (1);
  69 }
  70
  71 /*
  72  * Clean up all extra memory used by the parser and exporter
  73  */
  74 static void uci_file_cleanup(struct uci_context *ctx)
  75 {
  76         struct uci_parse_context *pctx;
  77
  78         if (ctx->buf) {
  79                 free(ctx->buf);
  80                 ctx->buf = NULL;
  81                 ctx->bufsz = 0;
  82         }
  83
  84         pctx = ctx->pctx;
  85         if (!pctx)
  86                 return;
  87
  88         ctx->pctx = NULL;
  89         if (pctx->package)
  90                 uci_free_package(pctx->package);
  91
  92         if (pctx->buf)
  93                 free(pctx->buf);
  94         if (pctx->file)
  95                 fclose(pctx->file);
  96
  97         free(pctx);
  98 }
  99
 100 /*
 101  * parse a character escaped by '\'
 102  * returns true if the escaped character is to be parsed
 103  * returns false if the escaped character is to be ignored
 104  */
 105 static inline bool parse_backslash(struct uci_context *ctx, char **str)
 106 {
 107         /* skip backslash */
 108         *str += 1;
 109
 110         /* undecoded backslash at the end of line, fetch the next line */
 111         if (!**str) {
 112                 *str += 1;
 113                 uci_getln(ctx, *str - ctx->pctx->buf);
 114                 return false;
 115         }
 116
 117         /* FIXME: decode escaped char, necessary? */
 118         return true;
 119 }
 120
 121 /*
 122  * move the string pointer forward until a non-whitespace character or
 123  * EOL is reached
 124  */
 125 static void skip_whitespace(struct uci_context *ctx, char **str)
 126 {
 127 restart:
 128         while (**str && isspace(**str))
 129                 *str += 1;
 130
 131         if (**str == '\\') {
 132                 if (!parse_backslash(ctx, str))
 133                         goto restart;
 134         }
 135 }
 136
 137 static inline void addc(char **dest, char **src)
 138 {
 139         **dest = **src;
 140         *dest += 1;
 141         *src += 1;
 142 }
 143
 144 /*
 145  * parse a double quoted string argument from the command line
 146  */
 147 static void parse_double_quote(struct uci_context *ctx, char **str, char **target)
 148 {
 149         char c;
 150
 151         /* skip quote character */
 152         *str += 1;
 153
 154         while ((c = **str)) {
 155                 switch(c) {
 156                 case '"':
 157                         **target = 0;
 158                         *str += 1;
 159                         return;
 160                 case '\\':
 161                         if (!parse_backslash(ctx, str))
 162                                 continue;
 163                         /* fall through */
 164                 default:
 165                         addc(target, str);
 166                         break;
 167                 }
 168         }
 169         ctx->pctx->reason = "unterminated \"";
 170         ctx->pctx->byte = *str - ctx->pctx->buf;
 171         UCI_THROW(ctx, UCI_ERR_PARSE);
 172 }
 173
 174 /*
 175  * parse a single quoted string argument from the command line
 176  */
 177 static void parse_single_quote(struct uci_context *ctx, char **str, char **target)
 178 {
 179         char c;
 180         /* skip quote character */
 181         *str += 1;
 182
 183         while ((c = **str)) {
 184                 switch(c) {
 185                 case '\'':
 186                         **target = 0;
 187                         *str += 1;
 188                         return;
 189                 default:
 190                         addc(target, str);
 191                 }
 192         }
 193         ctx->pctx->reason = "unterminated '";
 194         ctx->pctx->byte = *str - ctx->pctx->buf;
 195         UCI_THROW(ctx, UCI_ERR_PARSE);
 196 }
 197
 198 /*
 199  * parse a string from the command line and detect the quoting style
 200  */
 201 static void parse_str(struct uci_context *ctx, char **str, char **target)
 202 {
 203         do {
 204                 switch(**str) {
 205                 case '\'':
 206                         parse_single_quote(ctx, str, target);
 207                         break;
 208                 case '"':
 209                         parse_double_quote(ctx, str, target);
 210                         break;
 211                 case 0:
 212                         goto done;
 213                 case '\\':
 214                         if (!parse_backslash(ctx, str))
 215                                 continue;
 216                         /* fall through */
 217                 default:
 218                         addc(target, str);
 219                         break;
 220                 }
 221         } while (**str && !isspace(**str));
 222 done:
 223
 224         /*
 225          * if the string was unquoted and we've stopped at a whitespace
 226          * character, skip to the next one, because the whitespace will
 227          * be overwritten by a null byte here
 228          */
 229         if (**str)
 230                 *str += 1;
 231
 232         /* terminate the parsed string */
 233         **target = 0;
 234 }
 235
 236 /*
 237  * extract the next argument from the command line
 238  */
 239 static char *next_arg(struct uci_context *ctx, char **str, bool required)
 240 {
 241         char *val;
 242         char *ptr;
 243
 244         val = ptr = *str;
 245         skip_whitespace(ctx, str);
 246         parse_str(ctx, str, &ptr);
 247         if (required && !*val) {
 248                 ctx->pctx->reason = "insufficient arguments";
 249                 ctx->pctx->byte = *str - ctx->pctx->buf;
 250                 UCI_THROW(ctx, UCI_ERR_PARSE);
 251         }
 252
 253         return val;
 254 }
 255
 256 /*
 257  * verify that the end of the line or command is reached.
 258  * throw an error if extra arguments are given on the command line
 259  */
 260 static void assert_eol(struct uci_context *ctx, char **str)
 261 {
 262         char *tmp;
 263
 264         tmp = next_arg(ctx, str, false);
 265         if (tmp && *tmp) {
 266                 ctx->pctx->reason = "too many arguments";
 267                 ctx->pctx->byte = tmp - ctx->pctx->buf;
 268                 UCI_THROW(ctx, UCI_ERR_PARSE);
 269         }
 270 }
 271
 272 /*
 273  * switch to a different config, either triggered by uci_load, or by a
 274  * 'package <...>' statement in the import file
 275  */
 276 static void uci_switch_config(struct uci_context *ctx)
 277 {
 278         struct uci_parse_context *pctx;
 279         struct uci_element *e;
 280         const char *name;
 281
 282         pctx = ctx->pctx;
 283         name = pctx->name;
 284
 285         /* add the last config to main config file list */
 286         if (pctx->package) {
 287                 uci_list_add(&ctx->root, &pctx->package->e.list);
 288
 289                 pctx->package = NULL;
 290                 pctx->section = NULL;
 291         }
 292
 293         if (!name)
 294                 return;
 295
 296         /*
 297          * if an older config under the same name exists, unload it
 298          * ignore errors here, e.g. if the config was not found
 299          */
 300         UCI_TRAP_SAVE(ctx, ignore);
 301         e = uci_lookup_list(ctx, &ctx->root, name);
 302         if (e)
 303                 uci_unload(ctx, uci_to_package(e));
 304         UCI_TRAP_RESTORE(ctx);
 305 ignore:
 306         ctx->errno = 0;
 307
 308         pctx->package = uci_alloc_package(ctx, name);
 309 }
 310
 311 /*
 312  * parse the 'package' uci command (next config package)
 313  */
 314 static void uci_parse_package(struct uci_context *ctx, char **str, bool single)
 315 {
 316         char *name = NULL;
 317
 318         /* command string null-terminated by strtok */
 319         *str += strlen(*str) + 1;
 320
 321         name = next_arg(ctx, str, true);
 322         assert_eol(ctx, str);
 323         if (single)
 324                 return;
 325
 326         ctx->pctx->name = name;
 327         uci_switch_config(ctx);
 328 }
 329
 330 /*
 331  * parse the 'config' uci command (open a section)
 332  */
 333 static void uci_parse_config(struct uci_context *ctx, char **str)
 334 {
 335         char *name = NULL;
 336         char *type = NULL;
 337
 338         if (!ctx->pctx->package) {
 339                 if (!ctx->pctx->name) {
 340                         ctx->pctx->byte = *str - ctx->pctx->buf;
 341                         ctx->pctx->reason = "attempting to import a file without a package name";
 342                         UCI_THROW(ctx, UCI_ERR_PARSE);
 343                 }
 344                 uci_switch_config(ctx);
 345         }
 346
 347         /* command string null-terminated by strtok */
 348         *str += strlen(*str) + 1;
 349
 350         type = next_arg(ctx, str, true);
 351         name = next_arg(ctx, str, false);
 352         assert_eol(ctx, str);
 353         ctx->pctx->section = uci_alloc_section(ctx->pctx->package, type, name);
 354 }
 355
 356 /*
 357  * parse the 'option' uci command (open a value)
 358  */
 359 static void uci_parse_option(struct uci_context *ctx, char **str)
 360 {
 361         char *name = NULL;
 362         char *value = NULL;
 363
 364         if (!ctx->pctx->section) {
 365                 ctx->pctx->byte = *str - ctx->pctx->buf;
 366                 ctx->pctx->reason = "option command found before the first section";
 367                 UCI_THROW(ctx, UCI_ERR_PARSE);
 368         }
 369         /* command string null-terminated by strtok */
 370         *str += strlen(*str) + 1;
 371
 372         name = next_arg(ctx, str, true);
 373         value = next_arg(ctx, str, true);
 374         assert_eol(ctx, str);
 375         uci_alloc_option(ctx->pctx->section, name, value);
 376 }
 377
 378
 379 /*
 380  * parse a complete input line, split up combined commands by ';'
 381  */
 382 static void uci_parse_line(struct uci_context *ctx, bool single)
 383 {
 384         struct uci_parse_context *pctx = ctx->pctx;
 385         char *word, *brk = NULL;
 386
 387         for (word = strtok_r(pctx->buf, ";", &brk);
 388                  word;
 389                  word = strtok_r(NULL, ";", &brk)) {
 390
 391                 char *pbrk = NULL;
 392                 word = strtok_r(word, " \t", &pbrk);
 393
 394                 switch(word[0]) {
 395                         case 'p':
 396                                 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
 397                                         uci_parse_package(ctx, &word, single);
 398                                 break;
 399                         case 'c':
 400                                 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
 401                                         uci_parse_config(ctx, &word);
 402                                 break;
 403                         case 'o':
 404                                 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
 405                                         uci_parse_option(ctx, &word);
 406                                 break;
 407                         default:
 408                                 pctx->reason = "unterminated command";
 409                                 pctx->byte = word - pctx->buf;
 410                                 UCI_THROW(ctx, UCI_ERR_PARSE);
 411                                 break;
 412                 }
 413         }
 414 }
 415
 416 /* max number of characters that escaping adds to the string */
 417 #define UCI_QUOTE_ESCAPE        "'\\''"
 418
 419 /*
 420  * escape an uci string for export
 421  */
 422 static char *uci_escape(struct uci_context *ctx, char *str)
 423 {
 424         char *s, *p;
 425         int pos = 0;
 426
 427         if (!ctx->buf) {
 428                 ctx->bufsz = LINEBUF;
 429                 ctx->buf = malloc(LINEBUF);
 430         }
 431
 432         s = str;
 433         p = strchr(str, '\'');
 434         if (!p)
 435                 return str;
 436
 437         do {
 438                 int len = p - s;
 439                 if (len > 0) {
 440                         if (p + sizeof(UCI_QUOTE_ESCAPE) - str >= ctx->bufsz) {
 441                                 ctx->bufsz *= 2;
 442                                 ctx->buf = realloc(ctx->buf, ctx->bufsz);
 443                                 if (!ctx->buf)
 444                                         UCI_THROW(ctx, UCI_ERR_MEM);
 445                         }
 446                         memcpy(&ctx->buf[pos], s, len);
 447                         pos += len;
 448                 }
 449                 strcpy(&ctx->buf[pos], UCI_QUOTE_ESCAPE);
 450                 pos += sizeof(UCI_QUOTE_ESCAPE);
 451                 s = p + 1;
 452         } while ((p = strchr(s, '\'')));
 453
 454         return ctx->buf;
 455 }
 456
 457
 458 /*
 459  * export a single config package to a file stream
 460  */
 461 static void uci_export_package(struct uci_package *p, FILE *stream, bool header)
 462 {
 463         struct uci_context *ctx = p->ctx;
 464         struct uci_element *s, *o;
 465
 466         fprintf(stream, "package '%s'\n", uci_escape(ctx, p->e.name));
 467         uci_foreach_element(&p->sections, s) {
 468                 struct uci_section *sec = uci_to_section(s);
 469                 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, sec->type));
 470                 fprintf(stream, " '%s'\n", uci_escape(ctx, sec->e.name));
 471                 uci_foreach_element(&sec->options, o) {
 472                         struct uci_option *opt = uci_to_option(o);
 473                         fprintf(stream, "\toption '%s'", uci_escape(ctx, opt->e.name));
 474                         fprintf(stream, " '%s'\n", uci_escape(ctx, opt->value));
 475                 }
 476         }
 477         fprintf(stream, "\n");
 478 }
 479
 480 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header)
 481 {
 482         struct uci_element *e;
 483
 484         UCI_HANDLE_ERR(ctx);
 485         UCI_ASSERT(ctx, stream != NULL);
 486
 487         if (package) {
 488                 uci_export_package(package, stream, header);
 489                 goto done;
 490         }
 491
 492         uci_foreach_element(&ctx->root, e) {
 493                 uci_export_package(uci_to_package(e), stream, header);
 494         }
 495 done:
 496         return 0;
 497 }
 498
 499 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single)
 500 {
 501         struct uci_parse_context *pctx;
 502
 503         /* make sure no memory from previous parse attempts is leaked */
 504         uci_file_cleanup(ctx);
 505
 506         pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 507         ctx->pctx = pctx;
 508         pctx->file = stream;
 509
 510         /*
 511          * If 'name' was supplied, assume that the supplied stream does not contain
 512          * the appropriate 'package <name>' string to specify the config name
 513          * NB: the config file can still override the package name
 514          */
 515         if (name)
 516                 pctx->name = name;
 517
 518         while (!feof(pctx->file)) {
 519                 uci_getln(ctx, 0);
 520                 if (pctx->buf[0])
 521                         uci_parse_line(ctx, single);
 522         }
 523
 524         if (package)
 525                 *package = pctx->package;
 526
 527         pctx->name = NULL;
 528         uci_switch_config(ctx);
 529
 530         /* no error happened, we can get rid of the parser context now */
 531         uci_file_cleanup(ctx);
 532
 533         return 0;
 534 }
 535
 536 int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package)
 537 {
 538         struct stat statbuf;
 539         char *filename;
 540         bool confdir;
 541         FILE *file;
 542         int fd;
 543
 544         UCI_HANDLE_ERR(ctx);
 545         UCI_ASSERT(ctx, name != NULL);
 546
 547         switch (name[0]) {
 548         case '.':
 549                 if (name[1] != '/')
 550                         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 551                 /* fall through */
 552         case '/':
 553                 /* absolute/relative path outside of /etc/config */
 554                 filename = uci_strdup(ctx, name);
 555                 name = strrchr(name, '/') + 1;
 556                 confdir = false;
 557                 break;
 558         default:
 559                 filename = uci_malloc(ctx, strlen(name) + sizeof(UCI_CONFDIR) + 2);
 560                 sprintf(filename, UCI_CONFDIR "/%s", name);
 561                 confdir = true;
 562                 break;
 563         }
 564
 565         if ((stat(filename, &statbuf) < 0) ||
 566                 ((statbuf.st_mode &  S_IFMT) != S_IFREG)) {
 567                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 568         }
 569
 570         fd = open(filename, O_RDONLY);
 571         if (fd <= 0)
 572                 UCI_THROW(ctx, UCI_ERR_IO);
 573
 574         if (flock(fd, LOCK_SH) < 0)
 575                 UCI_THROW(ctx, UCI_ERR_IO);
 576
 577         file = fdopen(fd, "r");
 578         if (!file)
 579                 UCI_THROW(ctx, UCI_ERR_IO);
 580
 581         ctx->errno = 0;
 582         UCI_TRAP_SAVE(ctx, done);
 583         uci_import(ctx, file, name, package, true);
 584         UCI_TRAP_RESTORE(ctx);
 585
 586         if (*package) {
 587                 (*package)->path = filename;
 588                 (*package)->confdir = confdir;
 589         }
 590
 591 done:
 592         flock(fd, LOCK_UN);
 593         fclose(file);
 594         return ctx->errno;
 595 }
 596
 597 int uci_commit(struct uci_context *ctx, struct uci_package *p)
 598 {
 599         FILE *f = NULL;
 600         int fd = 0;
 601         int err = UCI_ERR_IO;
 602
 603         UCI_HANDLE_ERR(ctx);
 604         UCI_ASSERT(ctx, p != NULL);
 605         UCI_ASSERT(ctx, p->path != NULL);
 606
 607         fd = open(p->path, O_RDWR);
 608         if (fd < 0)
 609                 goto done;
 610
 611         if (flock(fd, LOCK_EX) < 0)
 612                 goto done;
 613
 614         ftruncate(fd, 0);
 615         f = fdopen(fd, "w");
 616         if (!f)
 617                 goto done;
 618
 619         UCI_TRAP_SAVE(ctx, done);
 620         uci_export(ctx, f, p, false);
 621         UCI_TRAP_RESTORE(ctx);
 622
 623 done:
 624         if (f)
 625                 fclose(f);
 626         else if (fd > 0)
 627                 close(fd);
 628
 629         if (ctx->errno)
 630                 UCI_THROW(ctx, ctx->errno);
 631         if (err)
 632                 UCI_THROW(ctx, UCI_ERR_IO);
 633         return 0;
 634 }
 635
 636
 637 /*
 638  * This function returns the filename by returning the string
 639  * after the last '/' character. By checking for a non-'\0'
 640  * character afterwards, directories are ignored (glob marks
 641  * those with a trailing '/'
 642  */
 643 static inline char *get_filename(char *path)
 644 {
 645         char *p;
 646
 647         p = strrchr(path, '/');
 648         p++;
 649         if (!*p)
 650                 return NULL;
 651         return p;
 652 }
 653
 654 char **uci_list_configs(struct uci_context *ctx)
 655 {
 656         char **configs;
 657         glob_t globbuf;
 658         int size, i;
 659         char *buf;
 660
 661         if (glob(UCI_CONFDIR "/*", GLOB_MARK, NULL, &globbuf) != 0)
 662                 return NULL;
 663
 664         size = sizeof(char *) * (globbuf.gl_pathc + 1);
 665         for(i = 0; i < globbuf.gl_pathc; i++) {
 666                 char *p;
 667
 668                 p = get_filename(globbuf.gl_pathv[i]);
 669                 if (!p)
 670                         continue;
 671
 672                 size += strlen(p) + 1;
 673         }
 674
 675         configs = malloc(size);
 676         if (!configs)
 677                 return NULL;
 678
 679         memset(configs, 0, size);
 680         buf = (char *) &configs[globbuf.gl_pathc + 1];
 681         for(i = 0; i < globbuf.gl_pathc; i++) {
 682                 char *p;
 683
 684                 p = get_filename(globbuf.gl_pathv[i]);
 685                 if (!p)
 686                         continue;
 687
 688                 configs[i] = buf;
 689                 strcpy(buf, p);
 690                 buf += strlen(buf) + 1;
 691         }
 692         return configs;
 693 }
 694
 695