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