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