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         struct uci_element *e;
 279         const char *name;
 280
 281         pctx = ctx->pctx;
 282         name = pctx->name;
 283
 284         /* add the last config to main config file list */
 285         if (pctx->package) {
 286                 uci_list_add(&ctx->root, &pctx->package->e.list);
 287
 288                 pctx->package = NULL;
 289                 pctx->section = NULL;
 290         }
 291
 292         if (!name)
 293                 return;
 294
 295         /*
 296          * if an older config under the same name exists, unload it
 297          * ignore errors here, e.g. if the config was not found
 298          */
 299         UCI_TRAP_SAVE(ctx, ignore);
 300         e = uci_lookup_list(ctx, &ctx->root, name);
 301         if (e)
 302                 uci_unload(ctx, uci_to_package(e));
 303         UCI_TRAP_RESTORE(ctx);
 304 ignore:
 305         ctx->errno = 0;
 306
 307         pctx->package = uci_alloc_package(ctx, name);
 308 }
 309
 310 /*
 311  * parse the 'package' uci command (next config package)
 312  */
 313 static void uci_parse_package(struct uci_context *ctx, char **str)
 314 {
 315         char *name = NULL;
 316
 317         /* command string null-terminated by strtok */
 318         *str += strlen(*str) + 1;
 319
 320         name = next_arg(ctx, str, true);
 321         assert_eol(ctx, str);
 322         ctx->pctx->name = name;
 323         uci_switch_config(ctx);
 324 }
 325
 326 /*
 327  * parse the 'config' uci command (open a section)
 328  */
 329 static void uci_parse_config(struct uci_context *ctx, char **str)
 330 {
 331         char *name = NULL;
 332         char *type = NULL;
 333
 334         if (!ctx->pctx->package) {
 335                 if (!ctx->pctx->name) {
 336                         ctx->pctx->byte = *str - ctx->pctx->buf;
 337                         ctx->pctx->reason = "attempting to import a file without a package name";
 338                         UCI_THROW(ctx, UCI_ERR_PARSE);
 339                 }
 340                 uci_switch_config(ctx);
 341         }
 342
 343         /* command string null-terminated by strtok */
 344         *str += strlen(*str) + 1;
 345
 346         type = next_arg(ctx, str, true);
 347         name = next_arg(ctx, str, false);
 348         assert_eol(ctx, str);
 349         ctx->pctx->section = uci_alloc_section(ctx->pctx->package, type, name);
 350 }
 351
 352 /*
 353  * parse the 'option' uci command (open a value)
 354  */
 355 static void uci_parse_option(struct uci_context *ctx, char **str)
 356 {
 357         char *name = NULL;
 358         char *value = NULL;
 359
 360         if (!ctx->pctx->section) {
 361                 ctx->pctx->byte = *str - ctx->pctx->buf;
 362                 ctx->pctx->reason = "option command found before the first section";
 363                 UCI_THROW(ctx, UCI_ERR_PARSE);
 364         }
 365         /* command string null-terminated by strtok */
 366         *str += strlen(*str) + 1;
 367
 368         name = next_arg(ctx, str, true);
 369         value = next_arg(ctx, str, true);
 370         assert_eol(ctx, str);
 371         uci_alloc_option(ctx->pctx->section, name, value);
 372 }
 373
 374
 375 /*
 376  * parse a complete input line, split up combined commands by ';'
 377  */
 378 static void uci_parse_line(struct uci_context *ctx)
 379 {
 380         struct uci_parse_context *pctx = ctx->pctx;
 381         char *word, *brk = NULL;
 382
 383         for (word = strtok_r(pctx->buf, ";", &brk);
 384                  word;
 385                  word = strtok_r(NULL, ";", &brk)) {
 386
 387                 char *pbrk = NULL;
 388                 word = strtok_r(word, " \t", &pbrk);
 389
 390                 switch(word[0]) {
 391                         case 'p':
 392                                 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
 393                                         uci_parse_package(ctx, &word);
 394                                 break;
 395                         case 'c':
 396                                 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
 397                                         uci_parse_config(ctx, &word);
 398                                 break;
 399                         case 'o':
 400                                 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
 401                                         uci_parse_option(ctx, &word);
 402                                 break;
 403                         default:
 404                                 pctx->reason = "unterminated command";
 405                                 pctx->byte = word - pctx->buf;
 406                                 UCI_THROW(ctx, UCI_ERR_PARSE);
 407                                 break;
 408                 }
 409         }
 410 }
 411
 412 /* max number of characters that escaping adds to the string */
 413 #define UCI_QUOTE_ESCAPE        "'\\'"
 414
 415 /*
 416  * escape an uci string for export
 417  */
 418 static char *uci_escape(struct uci_context *ctx, char *str)
 419 {
 420         char *s, *p;
 421         int pos = 0;
 422
 423         if (!ctx->buf) {
 424                 ctx->bufsz = LINEBUF;
 425                 ctx->buf = malloc(LINEBUF);
 426         }
 427
 428         s = str;
 429         p = strchr(str, '\'');
 430         if (!p)
 431                 return str;
 432
 433         do {
 434                 int len = p - s;
 435                 if (len > 0) {
 436                         if (p + sizeof(UCI_QUOTE_ESCAPE) - str >= ctx->bufsz) {
 437                                 ctx->bufsz *= 2;
 438                                 ctx->buf = realloc(ctx->buf, ctx->bufsz);
 439                                 if (!ctx->buf)
 440                                         UCI_THROW(ctx, UCI_ERR_MEM);
 441                         }
 442                         memcpy(&ctx->buf[pos], s, len);
 443                         pos += len;
 444                 }
 445                 strcpy(&ctx->buf[pos], UCI_QUOTE_ESCAPE);
 446                 pos += sizeof(UCI_QUOTE_ESCAPE);
 447                 s = p + 1;
 448         } while ((p = strchr(s, '\'')));
 449
 450         return ctx->buf;
 451 }
 452
 453
 454 /*
 455  * export a single config package to a file stream
 456  */
 457 static void uci_export_package(struct uci_package *p, FILE *stream)
 458 {
 459         struct uci_context *ctx = p->ctx;
 460         struct uci_element *s, *o;
 461
 462         fprintf(stream, "package '%s'\n", uci_escape(ctx, p->e.name));
 463         uci_foreach_element(&p->sections, s) {
 464                 struct uci_section *sec = uci_to_section(s);
 465                 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, sec->type));
 466                 fprintf(stream, " '%s'\n", uci_escape(ctx, sec->e.name));
 467                 uci_foreach_element(&sec->options, o) {
 468                         struct uci_option *opt = uci_to_option(o);
 469                         fprintf(stream, "\toption '%s'", uci_escape(ctx, opt->e.name));
 470                         fprintf(stream, " '%s'\n", uci_escape(ctx, opt->value));
 471                 }
 472         }
 473         fprintf(stream, "\n");
 474 }
 475
 476 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package)
 477 {
 478         struct uci_element *e;
 479
 480         UCI_HANDLE_ERR(ctx);
 481         UCI_ASSERT(ctx, stream != NULL);
 482
 483         if (package) {
 484                 uci_export_package(package, stream);
 485                 goto done;
 486         }
 487
 488         uci_foreach_element(&ctx->root, e) {
 489                 uci_export_package(uci_to_package(e), stream);
 490         }
 491 done:
 492         return 0;
 493 }
 494
 495 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package)
 496 {
 497         struct uci_parse_context *pctx;
 498
 499         /* make sure no memory from previous parse attempts is leaked */
 500         uci_file_cleanup(ctx);
 501
 502         pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 503         ctx->pctx = pctx;
 504         pctx->file = stream;
 505
 506         /*
 507          * If 'name' was supplied, assume that the supplied stream does not contain
 508          * the appropriate 'package <name>' string to specify the config name
 509          * NB: the config file can still override the package name
 510          */
 511         if (name)
 512                 pctx->name = name;
 513
 514         while (!feof(pctx->file)) {
 515                 uci_getln(ctx, 0);
 516                 if (pctx->buf[0])
 517                         uci_parse_line(ctx);
 518         }
 519
 520         if (package)
 521                 *package = pctx->package;
 522
 523         pctx->name = NULL;
 524         uci_switch_config(ctx);
 525
 526         /* no error happened, we can get rid of the parser context now */
 527         uci_file_cleanup(ctx);
 528
 529         return 0;
 530 }
 531
 532 int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package)
 533 {
 534         struct stat statbuf;
 535         char *filename;
 536         bool confdir;
 537         FILE *file;
 538         int fd;
 539
 540         UCI_HANDLE_ERR(ctx);
 541         UCI_ASSERT(ctx, name != NULL);
 542
 543         switch (name[0]) {
 544         case '.':
 545                 if (name[1] != '/')
 546                         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 547                 /* fall through */
 548         case '/':
 549                 /* absolute/relative path outside of /etc/config */
 550                 filename = uci_strdup(ctx, name);
 551                 name = strrchr(name, '/') + 1;
 552                 confdir = false;
 553                 break;
 554         default:
 555                 filename = uci_malloc(ctx, strlen(name) + sizeof(UCI_CONFDIR) + 2);
 556                 sprintf(filename, UCI_CONFDIR "/%s", name);
 557                 confdir = true;
 558                 break;
 559         }
 560
 561         if ((stat(filename, &statbuf) < 0) ||
 562                 ((statbuf.st_mode &  S_IFMT) != S_IFREG)) {
 563                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 564         }
 565
 566         fd = open(filename, O_RDONLY);
 567         if (fd <= 0)
 568                 UCI_THROW(ctx, UCI_ERR_IO);
 569
 570         flock(fd, LOCK_SH);
 571         file = fdopen(fd, "r");
 572         if (!file)
 573                 UCI_THROW(ctx, UCI_ERR_IO);
 574
 575         ctx->errno = 0;
 576         UCI_TRAP_SAVE(ctx, done);
 577         uci_import(ctx, file, name, package);
 578         UCI_TRAP_RESTORE(ctx);
 579
 580         if (*package) {
 581                 (*package)->path = filename;
 582                 (*package)->confdir = confdir;
 583         }
 584
 585 done:
 586         flock(fd, LOCK_UN);
 587         fclose(file);
 588         return ctx->errno;
 589 }
 590
 591 /*
 592  * This function returns the filename by returning the string
 593  * after the last '/' character. By checking for a non-'\0'
 594  * character afterwards, directories are ignored (glob marks
 595  * those with a trailing '/'
 596  */
 597 static inline char *get_filename(char *path)
 598 {
 599         char *p;
 600
 601         p = strrchr(path, '/');
 602         p++;
 603         if (!*p)
 604                 return NULL;
 605         return p;
 606 }
 607
 608 char **uci_list_configs(struct uci_context *ctx)
 609 {
 610         char **configs;
 611         glob_t globbuf;
 612         int size, i;
 613         char *buf;
 614
 615         if (glob(UCI_CONFDIR "/*", GLOB_MARK, NULL, &globbuf) != 0)
 616                 return NULL;
 617
 618         size = sizeof(char *) * (globbuf.gl_pathc + 1);
 619         for(i = 0; i < globbuf.gl_pathc; i++) {
 620                 char *p;
 621
 622                 p = get_filename(globbuf.gl_pathv[i]);
 623                 if (!p)
 624                         continue;
 625
 626                 size += strlen(p) + 1;
 627         }
 628
 629         configs = malloc(size);
 630         if (!configs)
 631                 return NULL;
 632
 633         memset(configs, 0, size);
 634         buf = (char *) &configs[globbuf.gl_pathc + 1];
 635         for(i = 0; i < globbuf.gl_pathc; i++) {
 636                 char *p;
 637
 638                 p = get_filename(globbuf.gl_pathv[i]);
 639                 if (!p)
 640                         continue;
 641
 642                 configs[i] = buf;
 643                 strcpy(buf, p);
 644                 buf += strlen(buf) + 1;
 645         }
 646         return configs;
 647 }
 648
 649