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->buf = NULL;
  79                 ctx->bufsz = 0;
  80         }
  81
  82         pctx = ctx->pctx;
  83         if (!pctx)
  84                 return;
  85
  86         ctx->pctx = NULL;
  87         if (pctx->package)
  88                 uci_free_package(pctx->package);
  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 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->package) {
 284                 uci_list_add(&ctx->root, &pctx->package->e.list);
 285
 286                 pctx->package = 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->package = uci_alloc_package(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         name = next_arg(ctx, str, true);
 317         assert_eol(ctx, str);
 318         ctx->pctx->name = name;
 319         uci_switch_config(ctx);
 320 }
 321
 322 /*
 323  * parse the 'config' uci command (open a section)
 324  */
 325 static void uci_parse_config(struct uci_context *ctx, char **str)
 326 {
 327         char *name = NULL;
 328         char *type = NULL;
 329
 330         if (!ctx->pctx->package) {
 331                 if (!ctx->pctx->name) {
 332                         ctx->pctx->byte = *str - ctx->pctx->buf;
 333                         ctx->pctx->reason = "attempting to import a file without a package name";
 334                         UCI_THROW(ctx, UCI_ERR_PARSE);
 335                 }
 336                 uci_switch_config(ctx);
 337         }
 338
 339         /* command string null-terminated by strtok */
 340         *str += strlen(*str) + 1;
 341
 342         type = next_arg(ctx, str, true);
 343         name = next_arg(ctx, str, false);
 344         assert_eol(ctx, str);
 345         ctx->pctx->section = uci_alloc_section(ctx->pctx->package, type, name);
 346 }
 347
 348 /*
 349  * parse the 'option' uci command (open a value)
 350  */
 351 static void uci_parse_option(struct uci_context *ctx, char **str)
 352 {
 353         char *name = NULL;
 354         char *value = NULL;
 355
 356         if (!ctx->pctx->section) {
 357                 ctx->pctx->byte = *str - ctx->pctx->buf;
 358                 ctx->pctx->reason = "option command found before the first section";
 359                 UCI_THROW(ctx, UCI_ERR_PARSE);
 360         }
 361         /* command string null-terminated by strtok */
 362         *str += strlen(*str) + 1;
 363
 364         name = next_arg(ctx, str, true);
 365         value = next_arg(ctx, str, true);
 366         assert_eol(ctx, str);
 367         uci_alloc_option(ctx->pctx->section, name, value);
 368 }
 369
 370
 371 /*
 372  * parse a complete input line, split up combined commands by ';'
 373  */
 374 static void uci_parse_line(struct uci_context *ctx)
 375 {
 376         struct uci_parse_context *pctx = ctx->pctx;
 377         char *word, *brk;
 378
 379         for (word = strtok_r(pctx->buf, ";", &brk);
 380                  word;
 381                  word = strtok_r(NULL, ";", &brk)) {
 382
 383                 char *pbrk;
 384                 word = strtok_r(word, " \t", &pbrk);
 385
 386                 switch(word[0]) {
 387                         case 'p':
 388                                 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
 389                                         uci_parse_package(ctx, &word);
 390                                 break;
 391                         case 'c':
 392                                 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
 393                                         uci_parse_config(ctx, &word);
 394                                 break;
 395                         case 'o':
 396                                 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
 397                                         uci_parse_option(ctx, &word);
 398                                 break;
 399                         default:
 400                                 pctx->reason = "unterminated command";
 401                                 pctx->byte = word - pctx->buf;
 402                                 UCI_THROW(ctx, UCI_ERR_PARSE);
 403                                 break;
 404                 }
 405         }
 406 }
 407
 408 /* max number of characters that escaping adds to the string */
 409 #define UCI_QUOTE_ESCAPE        "'\\'"
 410
 411 /*
 412  * escape an uci string for export
 413  */
 414 static char *uci_escape(struct uci_context *ctx, char *str)
 415 {
 416         char *s, *p;
 417         int pos = 0;
 418
 419         if (!ctx->buf) {
 420                 ctx->bufsz = LINEBUF;
 421                 ctx->buf = malloc(LINEBUF);
 422         }
 423
 424         s = str;
 425         p = strchr(str, '\'');
 426         if (!p)
 427                 return str;
 428
 429         do {
 430                 int len = p - s;
 431                 if (len > 0) {
 432                         if (p + sizeof(UCI_QUOTE_ESCAPE) - str >= ctx->bufsz) {
 433                                 ctx->bufsz *= 2;
 434                                 ctx->buf = realloc(ctx->buf, ctx->bufsz);
 435                                 if (!ctx->buf)
 436                                         UCI_THROW(ctx, UCI_ERR_MEM);
 437                         }
 438                         memcpy(&ctx->buf[pos], s, len);
 439                         pos += len;
 440                 }
 441                 strcpy(&ctx->buf[pos], UCI_QUOTE_ESCAPE);
 442                 pos += sizeof(UCI_QUOTE_ESCAPE);
 443                 s = p + 1;
 444         } while ((p = strchr(s, '\'')));
 445
 446         return ctx->buf;
 447 }
 448
 449
 450 /*
 451  * export a single config package to a file stream
 452  */
 453 static void uci_export_package(struct uci_package *p, FILE *stream)
 454 {
 455         struct uci_context *ctx = p->ctx;
 456         struct uci_element *s, *o;
 457
 458         fprintf(stream, "package '%s'\n", uci_escape(ctx, p->e.name));
 459         uci_foreach_element(&p->sections, s) {
 460                 struct uci_section *sec = uci_to_section(s);
 461                 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, sec->type));
 462                 fprintf(stream, " '%s'\n", uci_escape(ctx, sec->e.name));
 463                 uci_foreach_element(&sec->options, o) {
 464                         struct uci_option *opt = uci_to_option(o);
 465                         fprintf(stream, "\toption '%s'", uci_escape(ctx, opt->e.name));
 466                         fprintf(stream, " '%s'\n", uci_escape(ctx, opt->value));
 467                 }
 468         }
 469         fprintf(stream, "\n");
 470 }
 471
 472 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package)
 473 {
 474         struct uci_element *e;
 475
 476         UCI_HANDLE_ERR(ctx);
 477         UCI_ASSERT(ctx, stream != NULL);
 478
 479         if (package) {
 480                 uci_export_package(package, stream);
 481                 goto done;
 482         }
 483
 484         uci_foreach_element(&ctx->root, e) {
 485                 uci_export_package(uci_to_package(e), stream);
 486         }
 487 done:
 488         return 0;
 489 }
 490
 491 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package)
 492 {
 493         struct uci_parse_context *pctx;
 494
 495         /* make sure no memory from previous parse attempts is leaked */
 496         uci_file_cleanup(ctx);
 497
 498         pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 499         ctx->pctx = pctx;
 500         pctx->file = stream;
 501
 502         /*
 503          * If 'name' was supplied, assume that the supplied stream does not contain
 504          * the appropriate 'package <name>' string to specify the config name
 505          * NB: the config file can still override the package name
 506          */
 507         if (name)
 508                 pctx->name = name;
 509
 510         while (!feof(pctx->file)) {
 511                 uci_getln(ctx, 0);
 512                 if (pctx->buf[0])
 513                         uci_parse_line(ctx);
 514         }
 515
 516         if (package)
 517                 *package = pctx->package;
 518
 519         pctx->name = NULL;
 520         uci_switch_config(ctx);
 521
 522         /* no error happened, we can get rid of the parser context now */
 523         uci_file_cleanup(ctx);
 524
 525         return 0;
 526 }
 527
 528 int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package)
 529 {
 530         struct stat statbuf;
 531         char *filename;
 532         bool confpath;
 533         FILE *file;
 534
 535         UCI_HANDLE_ERR(ctx);
 536         UCI_ASSERT(ctx, name != NULL);
 537
 538         switch (name[0]) {
 539         case '.':
 540         case '/':
 541                 /* absolute/relative path outside of /etc/config */
 542                 filename = (char *) name;
 543                 confpath = false;
 544                 break;
 545         default:
 546                 filename = uci_malloc(ctx, strlen(name) + sizeof(UCI_CONFDIR) + 2);
 547                 sprintf(filename, UCI_CONFDIR "/%s", name);
 548                 confpath = true;
 549                 break;
 550         }
 551
 552         if ((stat(filename, &statbuf) < 0) ||
 553                 ((statbuf.st_mode &  S_IFMT) != S_IFREG)) {
 554                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 555         }
 556
 557         file = fopen(filename, "r");
 558         if (filename != name)
 559                 free(filename);
 560
 561         if (!file)
 562                 UCI_THROW(ctx, UCI_ERR_IO);
 563
 564         return uci_import(ctx, file, name, package);
 565 }
 566