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 <stdio.h>
  23 #include <ctype.h>
  24
  25 #define LINEBUF 32
  26 #define LINEBUF_MAX     4096
  27
  28 /*
  29  * Fetch a new line from the input stream and resize buffer if necessary
  30  */
  31 static void uci_getln(struct uci_context *ctx, int offset)
  32 {
  33         struct uci_parse_context *pctx = ctx->pctx;
  34         char *p;
  35         int ofs;
  36
  37         if (pctx->buf == NULL) {
  38                 pctx->buf = uci_malloc(ctx, LINEBUF);
  39                 pctx->bufsz = LINEBUF;
  40         }
  41
  42         ofs = offset;
  43         do {
  44                 p = &pctx->buf[ofs];
  45                 p[ofs] = 0;
  46
  47                 p = fgets(p, pctx->bufsz - ofs, pctx->file);
  48                 if (!p || !*p)
  49                         return;
  50
  51                 ofs += strlen(p);
  52                 if (pctx->buf[ofs - 1] == '\n') {
  53                         pctx->line++;
  54                         pctx->buf[ofs - 1] = 0;
  55                         return;
  56                 }
  57
  58                 if (pctx->bufsz > LINEBUF_MAX/2) {
  59                         pctx->reason = "line too long";
  60                         pctx->byte = LINEBUF_MAX;
  61                         UCI_THROW(ctx, UCI_ERR_PARSE);
  62                 }
  63
  64                 pctx->bufsz *= 2;
  65                 pctx->buf = uci_realloc(ctx, pctx->buf, pctx->bufsz);
  66         } while (1);
  67 }
  68
  69 /*
  70  * Clean up all extra memory used by the parser and exporter
  71  */
  72 static void uci_file_cleanup(struct uci_context *ctx)
  73 {
  74         struct uci_parse_context *pctx;
  75
  76         if (ctx->buf) {
  77                 free(ctx->buf);
  78                 ctx->bufsz = 0;
  79         }
  80
  81         pctx = ctx->pctx;
  82         if (!pctx)
  83                 return;
  84
  85         ctx->pctx = NULL;
  86         if (pctx->cfg) {
  87                 uci_list_del(&pctx->cfg->list);
  88                 uci_drop_config(pctx->cfg);
  89         }
  90         if (pctx->buf)
  91                 free(pctx->buf);
  92         if (pctx->file)
  93                 fclose(pctx->file);
  94
  95         free(pctx);
  96 }
  97
  98 /*
  99  * parse a character escaped by '\'
 100  * returns true if the escaped character is to be parsed
 101  * returns false if the escaped character is to be ignored
 102  */
 103 static inline bool parse_backslash(struct uci_context *ctx, char **str)
 104 {
 105         /* skip backslash */
 106         *str += 1;
 107
 108         /* undecoded backslash at the end of line, fetch the next line */
 109         if (!**str) {
 110                 *str += 1;
 111                 uci_getln(ctx, *str - ctx->pctx->buf);
 112                 return false;
 113         }
 114
 115         /* FIXME: decode escaped char, necessary? */
 116         return true;
 117 }
 118
 119 /*
 120  * move the string pointer forward until a non-whitespace character or
 121  * EOL is reached
 122  */
 123 static void skip_whitespace(struct uci_context *ctx, char **str)
 124 {
 125 restart:
 126         while (**str && isspace(**str))
 127                 *str += 1;
 128
 129         if (**str == '\\') {
 130                 if (!parse_backslash(ctx, str))
 131                         goto restart;
 132         }
 133 }
 134
 135 static inline void addc(char **dest, char **src)
 136 {
 137         **dest = **src;
 138         *dest += 1;
 139         *src += 1;
 140 }
 141
 142 /*
 143  * parse a double quoted string argument from the command line
 144  */
 145 static void parse_double_quote(struct uci_context *ctx, char **str, char **target)
 146 {
 147         char c;
 148
 149         /* skip quote character */
 150         *str += 1;
 151
 152         while ((c = **str)) {
 153                 switch(c) {
 154                 case '"':
 155                         **target = 0;
 156                         *str += 1;
 157                         return;
 158                 case '\\':
 159                         if (!parse_backslash(ctx, str))
 160                                 continue;
 161                         /* fall through */
 162                 default:
 163                         addc(target, str);
 164                         break;
 165                 }
 166         }
 167         ctx->pctx->reason = "unterminated \"";
 168         ctx->pctx->byte = *str - ctx->pctx->buf;
 169         UCI_THROW(ctx, UCI_ERR_PARSE);
 170 }
 171
 172 /*
 173  * parse a single quoted string argument from the command line
 174  */
 175 static void parse_single_quote(struct uci_context *ctx, char **str, char **target)
 176 {
 177         char c;
 178         /* skip quote character */
 179         *str += 1;
 180
 181         while ((c = **str)) {
 182                 switch(c) {
 183                 case '\'':
 184                         **target = 0;
 185                         *str += 1;
 186                         return;
 187                 default:
 188                         addc(target, str);
 189                 }
 190         }
 191         ctx->pctx->reason = "unterminated '";
 192         ctx->pctx->byte = *str - ctx->pctx->buf;
 193         UCI_THROW(ctx, UCI_ERR_PARSE);
 194 }
 195
 196 /*
 197  * parse a string from the command line and detect the quoting style
 198  */
 199 static void parse_str(struct uci_context *ctx, char **str, char **target)
 200 {
 201         do {
 202                 switch(**str) {
 203                 case '\'':
 204                         parse_single_quote(ctx, str, target);
 205                         break;
 206                 case '"':
 207                         parse_double_quote(ctx, str, target);
 208                         break;
 209                 case 0:
 210                         goto done;
 211                 case '\\':
 212                         if (!parse_backslash(ctx, str))
 213                                 continue;
 214                         /* fall through */
 215                 default:
 216                         addc(target, str);
 217                         break;
 218                 }
 219         } while (**str && !isspace(**str));
 220 done:
 221
 222         /*
 223          * if the string was unquoted and we've stopped at a whitespace
 224          * character, skip to the next one, because the whitespace will
 225          * be overwritten by a null byte here
 226          */
 227         if (**str)
 228                 *str += 1;
 229
 230         /* terminate the parsed string */
 231         **target = 0;
 232 }
 233
 234 /*
 235  * extract the next argument from the command line
 236  */
 237 static char *next_arg(struct uci_context *ctx, char **str, bool required)
 238 {
 239         char *val;
 240         char *ptr;
 241
 242         val = ptr = *str;
 243         skip_whitespace(ctx, str);
 244         parse_str(ctx, str, &ptr);
 245         if (required && !*val) {
 246                 ctx->pctx->reason = "insufficient arguments";
 247                 ctx->pctx->byte = *str - ctx->pctx->buf;
 248                 UCI_THROW(ctx, UCI_ERR_PARSE);
 249         }
 250
 251         return uci_strdup(ctx, val);
 252 }
 253
 254 /*
 255  * verify that the end of the line or command is reached.
 256  * throw an error if extra arguments are given on the command line
 257  */
 258 static void assert_eol(struct uci_context *ctx, char **str)
 259 {
 260         char *tmp;
 261
 262         tmp = next_arg(ctx, str, false);
 263         if (tmp && *tmp) {
 264                 ctx->pctx->reason = "too many arguments";
 265                 ctx->pctx->byte = tmp - ctx->pctx->buf;
 266                 UCI_THROW(ctx, UCI_ERR_PARSE);
 267         }
 268 }
 269
 270 /*
 271  * switch to a different config, either triggered by uci_load, or by a
 272  * 'package <...>' statement in the import file
 273  */
 274 static void uci_switch_config(struct uci_context *ctx)
 275 {
 276         struct uci_parse_context *pctx;
 277         const char *name;
 278
 279         pctx = ctx->pctx;
 280         name = pctx->name;
 281
 282         /* add the last config to main config file list */
 283         if (pctx->cfg) {
 284                 uci_list_add(&ctx->root, &pctx->cfg->list);
 285
 286                 pctx->cfg = NULL;
 287                 pctx->section = NULL;
 288         }
 289
 290         if (!name)
 291                 return;
 292
 293         /*
 294          * if an older config under the same name exists, unload it
 295          * ignore errors here, e.g. if the config was not found
 296          */
 297         UCI_TRAP_SAVE(ctx, ignore);
 298         uci_unload(ctx, name);
 299         UCI_TRAP_RESTORE(ctx);
 300 ignore:
 301         ctx->errno = 0;
 302
 303         pctx->cfg = uci_alloc_config(ctx, name);
 304 }
 305
 306 /*
 307  * parse the 'package' uci command (next config package)
 308  */
 309 static void uci_parse_package(struct uci_context *ctx, char **str)
 310 {
 311         char *name = NULL;
 312
 313         /* command string null-terminated by strtok */
 314         *str += strlen(*str) + 1;
 315
 316         UCI_TRAP_SAVE(ctx, error);
 317         name = next_arg(ctx, str, true);
 318         assert_eol(ctx, str);
 319         ctx->pctx->name = name;
 320         uci_switch_config(ctx);
 321         UCI_TRAP_RESTORE(ctx);
 322         return;
 323
 324 error:
 325         if (name)
 326                 free(name);
 327         UCI_THROW(ctx, ctx->errno);
 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->cfg) {
 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         UCI_TRAP_SAVE(ctx, error);
 351         type = next_arg(ctx, str, true);
 352         name = next_arg(ctx, str, false);
 353         assert_eol(ctx, str);
 354         ctx->pctx->section = uci_add_section(ctx->pctx->cfg, type, name);
 355         UCI_TRAP_RESTORE(ctx);
 356         return;
 357
 358 error:
 359         if (name)
 360                 free(name);
 361         if (type)
 362                 free(type);
 363         UCI_THROW(ctx, ctx->errno);
 364 }
 365
 366 /*
 367  * parse the 'option' uci command (open a value)
 368  */
 369 static void uci_parse_option(struct uci_context *ctx, char **str)
 370 {
 371         char *name = NULL;
 372         char *value = NULL;
 373
 374         if (!ctx->pctx->section) {
 375                 ctx->pctx->byte = *str - ctx->pctx->buf;
 376                 ctx->pctx->reason = "option command found before the first section";
 377                 UCI_THROW(ctx, UCI_ERR_PARSE);
 378         }
 379         /* command string null-terminated by strtok */
 380         *str += strlen(*str) + 1;
 381
 382         UCI_TRAP_SAVE(ctx, error);
 383         name = next_arg(ctx, str, true);
 384         value = next_arg(ctx, str, true);
 385         assert_eol(ctx, str);
 386         uci_add_option(ctx->pctx->section, name, value);
 387         UCI_TRAP_RESTORE(ctx);
 388         return;
 389
 390 error:
 391         if (name)
 392                 free(name);
 393         if (value)
 394                 free(value);
 395         UCI_THROW(ctx, ctx->errno);
 396 }
 397
 398
 399 /*
 400  * parse a complete input line, split up combined commands by ';'
 401  */
 402 static void uci_parse_line(struct uci_context *ctx)
 403 {
 404         struct uci_parse_context *pctx = ctx->pctx;
 405         char *word, *brk;
 406
 407         for (word = strtok_r(pctx->buf, ";", &brk);
 408                  word;
 409                  word = strtok_r(NULL, ";", &brk)) {
 410
 411                 char *pbrk;
 412                 word = strtok_r(word, " \t", &pbrk);
 413
 414                 switch(word[0]) {
 415                         case 'p':
 416                                 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
 417                                         uci_parse_package(ctx, &word);
 418                                 break;
 419                         case 'c':
 420                                 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
 421                                         uci_parse_config(ctx, &word);
 422                                 break;
 423                         case 'o':
 424                                 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
 425                                         uci_parse_option(ctx, &word);
 426                                 break;
 427                         default:
 428                                 pctx->reason = "unterminated command";
 429                                 pctx->byte = word - pctx->buf;
 430                                 UCI_THROW(ctx, UCI_ERR_PARSE);
 431                                 break;
 432                 }
 433         }
 434 }
 435
 436 /* max number of characters that escaping adds to the string */
 437 #define UCI_QUOTE_ESCAPE        "'\\'"
 438
 439 /*
 440  * escape an uci string for export
 441  */
 442 static char *uci_escape(struct uci_context *ctx, char *str)
 443 {
 444         char *s, *p, *t;
 445         int pos = 0;
 446
 447         if (!ctx->buf) {
 448                 ctx->bufsz = LINEBUF;
 449                 ctx->buf = malloc(LINEBUF);
 450         }
 451
 452         s = str;
 453         p = strchr(str, '\'');
 454         if (!p)
 455                 return str;
 456
 457         do {
 458                 int len = p - s;
 459                 if (len > 0) {
 460                         if (p + sizeof(UCI_QUOTE_ESCAPE) - str >= ctx->bufsz) {
 461                                 ctx->bufsz *= 2;
 462                                 ctx->buf = realloc(ctx->buf, ctx->bufsz);
 463                                 if (!ctx->buf)
 464                                         UCI_THROW(ctx, UCI_ERR_MEM);
 465                         }
 466                         memcpy(&ctx->buf[pos], s, len);
 467                         pos += len;
 468                 }
 469                 strcpy(&ctx->buf[pos], UCI_QUOTE_ESCAPE);
 470                 pos += sizeof(UCI_QUOTE_ESCAPE);
 471                 s = p + 1;
 472         } while ((p = strchr(s, '\'')));
 473
 474         return ctx->buf;
 475 }
 476
 477
 478 /*
 479  * export a single config package to a file stream
 480  */
 481 static void uci_export_config(struct uci_config *cfg, FILE *stream)
 482 {
 483         struct uci_context *ctx = cfg->ctx;
 484         struct uci_section *s;
 485         struct uci_option *o;
 486
 487         fprintf(stream, "package '%s'\n", uci_escape(ctx, cfg->name));
 488         uci_foreach_entry(section, &cfg->sections, s) {
 489                 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, s->type));
 490                 fprintf(stream, " '%s'\n", uci_escape(ctx, s->name));
 491                 uci_foreach_entry(option, &s->options, o) {
 492                         fprintf(stream, "\toption '%s'", uci_escape(ctx, o->name));
 493                         fprintf(stream, " '%s'\n", uci_escape(ctx, o->value));
 494                 }
 495         }
 496         fprintf(stream, "\n");
 497 }
 498
 499 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_config *cfg)
 500 {
 501         UCI_HANDLE_ERR(ctx);
 502         UCI_ASSERT(ctx, stream != NULL);
 503
 504         if (cfg) {
 505                 uci_export_config(cfg, stream);
 506                 goto done;
 507         }
 508
 509         uci_foreach_entry(config, &ctx->root, cfg) {
 510                 uci_export_config(cfg, stream);
 511         }
 512 done:
 513         return 0;
 514 }
 515
 516 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_config **cfg)
 517 {
 518         struct uci_parse_context *pctx;
 519
 520         /* make sure no memory from previous parse attempts is leaked */
 521         uci_file_cleanup(ctx);
 522
 523         pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 524         ctx->pctx = pctx;
 525         pctx->file = stream;
 526
 527         /*
 528          * If 'name' was supplied, assume that the supplied stream does not contain
 529          * the appropriate 'package <name>' string to specify the config name
 530          * NB: the config file can still override the package name
 531          */
 532         if (name)
 533                 pctx->name = name;
 534
 535         while (!feof(pctx->file)) {
 536                 uci_getln(ctx, 0);
 537                 if (pctx->buf[0])
 538                         uci_parse_line(ctx);
 539         }
 540
 541         if (cfg)
 542                 *cfg = pctx->cfg;
 543
 544         pctx->name = NULL;
 545         uci_switch_config(ctx);
 546
 547         /* no error happened, we can get rid of the parser context now */
 548         uci_file_cleanup(ctx);
 549
 550         return 0;
 551 }
 552
 553 int uci_load(struct uci_context *ctx, const char *name, struct uci_config **cfg)
 554 {
 555         struct stat statbuf;
 556         char *filename;
 557         bool confpath;
 558         FILE *file;
 559
 560         UCI_HANDLE_ERR(ctx);
 561         UCI_ASSERT(ctx, name != NULL);
 562
 563 ignore:
 564         ctx->errno = 0;
 565
 566         switch (name[0]) {
 567         case '.':
 568         case '/':
 569                 /* absolute/relative path outside of /etc/config */
 570                 filename = (char *) name;
 571                 confpath = false;
 572                 break;
 573         default:
 574                 filename = uci_malloc(ctx, strlen(name) + sizeof(UCI_CONFDIR) + 2);
 575                 sprintf(filename, UCI_CONFDIR "/%s", name);
 576                 confpath = true;
 577                 break;
 578         }
 579
 580         if ((stat(filename, &statbuf) < 0) ||
 581                 ((statbuf.st_mode &  S_IFMT) != S_IFREG)) {
 582                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 583         }
 584
 585         file = fopen(filename, "r");
 586         if (filename != name)
 587                 free(filename);
 588
 589         if (!file)
 590                 UCI_THROW(ctx, UCI_ERR_IO);
 591
 592         return uci_import(ctx, file, name, cfg);
 593 }
 594