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 #define _GNU_SOURCE
  20 #include <sys/types.h>
  21 #include <sys/file.h>
  22 #include <stdbool.h>
  23 #include <unistd.h>
  24 #include <fcntl.h>
  25 #include <stdio.h>
  26 #include <ctype.h>
  27
  28 /*
  29  * Clean up all extra memory used by the parser and exporter
  30  */
  31 static void uci_file_cleanup(struct uci_context *ctx)
  32 {
  33         struct uci_parse_context *pctx;
  34
  35         if (ctx->buf) {
  36                 free(ctx->buf);
  37                 ctx->buf = NULL;
  38                 ctx->bufsz = 0;
  39         }
  40
  41         pctx = ctx->pctx;
  42         if (!pctx)
  43                 return;
  44
  45         ctx->pctx = NULL;
  46         if (pctx->package)
  47                 uci_free_package(&pctx->package);
  48
  49         if (pctx->buf)
  50                 free(pctx->buf);
  51
  52         free(pctx);
  53 }
  54
  55
  56 /*
  57  * parse a character escaped by '\'
  58  * returns true if the escaped character is to be parsed
  59  * returns false if the escaped character is to be ignored
  60  */
  61 static inline bool parse_backslash(struct uci_context *ctx, char **str)
  62 {
  63         /* skip backslash */
  64         *str += 1;
  65
  66         /* undecoded backslash at the end of line, fetch the next line */
  67         if (!**str) {
  68                 *str += 1;
  69                 uci_getln(ctx, *str - ctx->pctx->buf);
  70                 return false;
  71         }
  72
  73         /* FIXME: decode escaped char, necessary? */
  74         return true;
  75 }
  76
  77 /*
  78  * move the string pointer forward until a non-whitespace character or
  79  * EOL is reached
  80  */
  81 static void skip_whitespace(struct uci_context *ctx, char **str)
  82 {
  83 restart:
  84         while (**str && isspace(**str))
  85                 *str += 1;
  86
  87         if (**str == '\\') {
  88                 if (!parse_backslash(ctx, str))
  89                         goto restart;
  90         }
  91 }
  92
  93 static inline void addc(char **dest, char **src)
  94 {
  95         **dest = **src;
  96         *dest += 1;
  97         *src += 1;
  98 }
  99
 100 /*
 101  * parse a double quoted string argument from the command line
 102  */
 103 static void parse_double_quote(struct uci_context *ctx, char **str, char **target)
 104 {
 105         char c;
 106
 107         /* skip quote character */
 108         *str += 1;
 109
 110         while ((c = **str)) {
 111                 switch(c) {
 112                 case '"':
 113                         **target = 0;
 114                         *str += 1;
 115                         return;
 116                 case '\\':
 117                         if (!parse_backslash(ctx, str))
 118                                 continue;
 119                         /* fall through */
 120                 default:
 121                         addc(target, str);
 122                         break;
 123                 }
 124         }
 125         uci_parse_error(ctx, *str, "unterminated \"");
 126 }
 127
 128 /*
 129  * parse a single quoted string argument from the command line
 130  */
 131 static void parse_single_quote(struct uci_context *ctx, char **str, char **target)
 132 {
 133         char c;
 134         /* skip quote character */
 135         *str += 1;
 136
 137         while ((c = **str)) {
 138                 switch(c) {
 139                 case '\'':
 140                         **target = 0;
 141                         *str += 1;
 142                         return;
 143                 default:
 144                         addc(target, str);
 145                 }
 146         }
 147         uci_parse_error(ctx, *str, "unterminated '");
 148 }
 149
 150 /*
 151  * parse a string from the command line and detect the quoting style
 152  */
 153 static void parse_str(struct uci_context *ctx, char **str, char **target)
 154 {
 155         do {
 156                 switch(**str) {
 157                 case '\'':
 158                         parse_single_quote(ctx, str, target);
 159                         break;
 160                 case '"':
 161                         parse_double_quote(ctx, str, target);
 162                         break;
 163                 case '#':
 164                         **str = 0;
 165                         /* fall through */
 166                 case 0:
 167                         goto done;
 168                 case '\\':
 169                         if (!parse_backslash(ctx, str))
 170                                 continue;
 171                         /* fall through */
 172                 default:
 173                         addc(target, str);
 174                         break;
 175                 }
 176         } while (**str && !isspace(**str));
 177 done:
 178
 179         /*
 180          * if the string was unquoted and we've stopped at a whitespace
 181          * character, skip to the next one, because the whitespace will
 182          * be overwritten by a null byte here
 183          */
 184         if (**str)
 185                 *str += 1;
 186
 187         /* terminate the parsed string */
 188         **target = 0;
 189 }
 190
 191 /*
 192  * extract the next argument from the command line
 193  */
 194 static char *next_arg(struct uci_context *ctx, char **str, bool required, bool name)
 195 {
 196         char *val;
 197         char *ptr;
 198
 199         val = ptr = *str;
 200         skip_whitespace(ctx, str);
 201         parse_str(ctx, str, &ptr);
 202         if (!*val) {
 203                 if (required)
 204                         uci_parse_error(ctx, *str, "insufficient arguments");
 205                 goto done;
 206         }
 207
 208         if (name && !uci_validate_name(val))
 209                 uci_parse_error(ctx, val, "invalid character in field");
 210
 211 done:
 212         return val;
 213 }
 214
 215 /*
 216  * verify that the end of the line or command is reached.
 217  * throw an error if extra arguments are given on the command line
 218  */
 219 static void assert_eol(struct uci_context *ctx, char **str)
 220 {
 221         char *tmp;
 222
 223         tmp = next_arg(ctx, str, false, false);
 224         if (tmp && *tmp && (ctx->flags & UCI_FLAG_STRICT))
 225                 uci_parse_error(ctx, *str, "too many arguments");
 226 }
 227
 228 /*
 229  * switch to a different config, either triggered by uci_load, or by a
 230  * 'package <...>' statement in the import file
 231  */
 232 static void uci_switch_config(struct uci_context *ctx)
 233 {
 234         struct uci_parse_context *pctx;
 235         struct uci_element *e;
 236         const char *name;
 237
 238         pctx = ctx->pctx;
 239         name = pctx->name;
 240
 241         /* add the last config to main config file list */
 242         if (pctx->package) {
 243                 uci_list_add(&ctx->root, &pctx->package->e.list);
 244
 245                 pctx->package = NULL;
 246                 pctx->section = NULL;
 247         }
 248
 249         if (!name)
 250                 return;
 251
 252         /*
 253          * if an older config under the same name exists, unload it
 254          * ignore errors here, e.g. if the config was not found
 255          */
 256         e = uci_lookup_list(ctx, &ctx->root, name);
 257         if (e)
 258                 UCI_THROW(ctx, UCI_ERR_DUPLICATE);
 259         pctx->package = uci_alloc_package(ctx, name);
 260 }
 261
 262 /*
 263  * parse the 'package' uci command (next config package)
 264  */
 265 static void uci_parse_package(struct uci_context *ctx, char **str, bool single)
 266 {
 267         char *name = NULL;
 268
 269         /* command string null-terminated by strtok */
 270         *str += strlen(*str) + 1;
 271
 272         name = next_arg(ctx, str, true, true);
 273         assert_eol(ctx, str);
 274         if (single)
 275                 return;
 276
 277         ctx->pctx->name = name;
 278         uci_switch_config(ctx);
 279 }
 280
 281 /* Based on an efficient hash function published by D. J. Bernstein */
 282 static unsigned int djbhash(unsigned int hash, char *str)
 283 {
 284         int len = strlen(str);
 285         int i;
 286
 287         /* initial value */
 288         if (hash == ~0)
 289                 hash = 5381;
 290
 291         for(i = 0; i < len; i++) {
 292                 hash = ((hash << 5) + hash) + str[i];
 293         }
 294         return (hash & 0x7FFFFFFF);
 295 }
 296
 297 /* fix up an unnamed section */
 298 static void uci_fixup_section(struct uci_context *ctx, struct uci_section *s)
 299 {
 300         unsigned int hash = ~0;
 301         struct uci_element *e;
 302         char buf[16];
 303
 304         if (!s || s->e.name)
 305                 return;
 306
 307         /*
 308          * Generate a name for unnamed sections. This is used as reference
 309          * when locating or updating the section from apps/scripts.
 310          * To make multiple concurrent versions somewhat safe for updating,
 311          * the name is generated from a hash of its type and name/value
 312          * pairs of its option, and it is prefixed by a counter value.
 313          * If the order of the unnamed sections changes for some reason,
 314          * updates to them will be rejected.
 315          */
 316         hash = djbhash(hash, s->type);
 317         uci_foreach_element(&s->options, e) {
 318                 hash = djbhash(hash, e->name);
 319                 hash = djbhash(hash, uci_to_option(e)->value);
 320         }
 321         sprintf(buf, "cfg%02x%04x", ++s->package->n_section, hash % (1 << 16));
 322         s->e.name = uci_strdup(ctx, buf);
 323 }
 324
 325 /*
 326  * parse the 'config' uci command (open a section)
 327  */
 328 static void uci_parse_config(struct uci_context *ctx, char **str)
 329 {
 330         struct uci_parse_context *pctx = ctx->pctx;
 331         char *name = NULL;
 332         char *type = NULL;
 333
 334         uci_fixup_section(ctx, ctx->pctx->section);
 335         if (!ctx->pctx->package) {
 336                 if (!ctx->pctx->name)
 337                         uci_parse_error(ctx, *str, "attempting to import a file without a package name");
 338
 339                 uci_switch_config(ctx);
 340         }
 341
 342         /* command string null-terminated by strtok */
 343         *str += strlen(*str) + 1;
 344
 345         type = next_arg(ctx, str, true, false);
 346         if (!uci_validate_str(type, false))
 347                 uci_parse_error(ctx, type, "invalid character in field");
 348         name = next_arg(ctx, str, false, true);
 349         assert_eol(ctx, str);
 350
 351         if (pctx->merge) {
 352                 UCI_TRAP_SAVE(ctx, error);
 353                 uci_set(ctx, pctx->package, name, NULL, type);
 354                 UCI_TRAP_RESTORE(ctx);
 355                 return;
 356 error:
 357                 UCI_THROW(ctx, ctx->errno);
 358         } else
 359                 pctx->section = uci_alloc_section(pctx->package, type, name);
 360 }
 361
 362 /*
 363  * parse the 'option' uci command (open a value)
 364  */
 365 static void uci_parse_option(struct uci_context *ctx, char **str)
 366 {
 367         struct uci_parse_context *pctx = ctx->pctx;
 368         char *name = NULL;
 369         char *value = NULL;
 370
 371         if (!pctx->section)
 372                 uci_parse_error(ctx, *str, "option command found before the first section");
 373
 374         /* command string null-terminated by strtok */
 375         *str += strlen(*str) + 1;
 376
 377         name = next_arg(ctx, str, true, true);
 378         value = next_arg(ctx, str, false, false);
 379         assert_eol(ctx, str);
 380
 381         if (pctx->merge) {
 382                 UCI_TRAP_SAVE(ctx, error);
 383                 uci_set(ctx, pctx->package, pctx->section->e.name, name, value);
 384                 UCI_TRAP_RESTORE(ctx);
 385                 return;
 386 error:
 387                 UCI_THROW(ctx, ctx->errno);
 388         } else
 389                 uci_alloc_option(pctx->section, name, value);
 390 }
 391
 392
 393 /*
 394  * parse a complete input line, split up combined commands by ';'
 395  */
 396 static void uci_parse_line(struct uci_context *ctx, bool single)
 397 {
 398         struct uci_parse_context *pctx = ctx->pctx;
 399         char *word, *brk = NULL;
 400
 401         for (word = strtok_r(pctx->buf, ";", &brk);
 402                  word;
 403                  word = strtok_r(NULL, ";", &brk)) {
 404
 405                 char *pbrk = NULL;
 406                 word = strtok_r(word, " \t", &pbrk);
 407
 408                 if (!word)
 409                         continue;
 410
 411                 switch(word[0]) {
 412                         case '#':
 413                                 return;
 414                         case 'p':
 415                                 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
 416                                         uci_parse_package(ctx, &word, single);
 417                                 break;
 418                         case 'c':
 419                                 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
 420                                         uci_parse_config(ctx, &word);
 421                                 break;
 422                         case 'o':
 423                                 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
 424                                         uci_parse_option(ctx, &word);
 425                                 break;
 426                         default:
 427                                 uci_parse_error(ctx, word, "unterminated command");
 428                                 break;
 429                 }
 430         }
 431 }
 432
 433 /* max number of characters that escaping adds to the string */
 434 #define UCI_QUOTE_ESCAPE        "'\\''"
 435
 436 /*
 437  * escape an uci string for export
 438  */
 439 static char *uci_escape(struct uci_context *ctx, char *str)
 440 {
 441         char *s, *p;
 442         int pos = 0;
 443
 444         if (!ctx->buf) {
 445                 ctx->bufsz = LINEBUF;
 446                 ctx->buf = malloc(LINEBUF);
 447         }
 448
 449         s = str;
 450         p = strchr(str, '\'');
 451         if (!p)
 452                 return str;
 453
 454         do {
 455                 int len = p - s;
 456                 if (len > 0) {
 457                         if (p + sizeof(UCI_QUOTE_ESCAPE) - str >= ctx->bufsz) {
 458                                 ctx->bufsz *= 2;
 459                                 ctx->buf = realloc(ctx->buf, ctx->bufsz);
 460                                 if (!ctx->buf)
 461                                         UCI_THROW(ctx, UCI_ERR_MEM);
 462                         }
 463                         memcpy(&ctx->buf[pos], s, len);
 464                         pos += len;
 465                 }
 466                 strcpy(&ctx->buf[pos], UCI_QUOTE_ESCAPE);
 467                 pos += sizeof(UCI_QUOTE_ESCAPE);
 468                 s = p + 1;
 469         } while ((p = strchr(s, '\'')));
 470
 471         return ctx->buf;
 472 }
 473
 474
 475 /*
 476  * export a single config package to a file stream
 477  */
 478 static void uci_export_package(struct uci_package *p, FILE *stream, bool header)
 479 {
 480         struct uci_context *ctx = p->ctx;
 481         struct uci_element *s, *o;
 482
 483         if (header)
 484                 fprintf(stream, "package '%s'\n", uci_escape(ctx, p->e.name));
 485         uci_foreach_element(&p->sections, s) {
 486                 struct uci_section *sec = uci_to_section(s);
 487                 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, sec->type));
 488                 if (!sec->anonymous || (ctx->flags & UCI_FLAG_EXPORT_NAME))
 489                         fprintf(stream, " '%s'", uci_escape(ctx, sec->e.name));
 490                 fprintf(stream, "\n");
 491                 uci_foreach_element(&sec->options, o) {
 492                         struct uci_option *opt = uci_to_option(o);
 493                         fprintf(stream, "\toption '%s'", uci_escape(ctx, opt->e.name));
 494                         fprintf(stream, " '%s'\n", uci_escape(ctx, opt->value));
 495                 }
 496         }
 497         fprintf(stream, "\n");
 498 }
 499
 500 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header)
 501 {
 502         struct uci_element *e;
 503
 504         UCI_HANDLE_ERR(ctx);
 505         UCI_ASSERT(ctx, stream != NULL);
 506
 507         if (package)
 508                 uci_export_package(package, stream, header);
 509         else {
 510                 uci_foreach_element(&ctx->root, e) {
 511                         uci_export_package(uci_to_package(e), stream, header);
 512                 }
 513         }
 514
 515         return 0;
 516 }
 517
 518 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single)
 519 {
 520         struct uci_parse_context *pctx;
 521         UCI_HANDLE_ERR(ctx);
 522
 523         /* make sure no memory from previous parse attempts is leaked */
 524         uci_file_cleanup(ctx);
 525
 526         uci_alloc_parse_context(ctx);
 527         pctx = ctx->pctx;
 528         pctx->file = stream;
 529         if (*package && single) {
 530                 pctx->package = *package;
 531                 pctx->merge = true;
 532         }
 533
 534         /*
 535          * If 'name' was supplied, assume that the supplied stream does not contain
 536          * the appropriate 'package <name>' string to specify the config name
 537          * NB: the config file can still override the package name
 538          */
 539         if (name) {
 540                 UCI_ASSERT(ctx, uci_validate_name(name));
 541                 pctx->name = name;
 542         }
 543
 544         while (!feof(pctx->file)) {
 545                 uci_getln(ctx, 0);
 546                 UCI_TRAP_SAVE(ctx, error);
 547                 if (pctx->buf[0])
 548                         uci_parse_line(ctx, single);
 549                 UCI_TRAP_RESTORE(ctx);
 550                 continue;
 551 error:
 552                 if (ctx->flags & UCI_FLAG_PERROR)
 553                         uci_perror(ctx, NULL);
 554                 if ((ctx->errno != UCI_ERR_PARSE) ||
 555                         (ctx->flags & UCI_FLAG_STRICT))
 556                         UCI_THROW(ctx, ctx->errno);
 557         }
 558
 559         uci_fixup_section(ctx, ctx->pctx->section);
 560         if (package)
 561                 *package = pctx->package;
 562         if (pctx->merge)
 563                 pctx->package = NULL;
 564
 565         pctx->name = NULL;
 566         uci_switch_config(ctx);
 567
 568         /* no error happened, we can get rid of the parser context now */
 569         uci_file_cleanup(ctx);
 570
 571         return 0;
 572 }
 573
 574
 575 static char *uci_config_path(struct uci_context *ctx, const char *name)
 576 {
 577         char *filename;
 578
 579         UCI_ASSERT(ctx, uci_validate_name(name));
 580         filename = uci_malloc(ctx, strlen(name) + strlen(ctx->confdir) + 2);
 581         sprintf(filename, "%s/%s", ctx->confdir, name);
 582
 583         return filename;
 584 }
 585
 586 int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package)
 587 {
 588         char *filename;
 589         bool confdir;
 590         FILE *file = NULL;
 591
 592         UCI_HANDLE_ERR(ctx);
 593
 594         switch (name[0]) {
 595         case '.':
 596                 /* relative path outside of /etc/config */
 597                 if (name[1] != '/')
 598                         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 599                 /* fall through */
 600         case '/':
 601                 /* absolute path outside of /etc/config */
 602                 filename = uci_strdup(ctx, name);
 603                 name = strrchr(name, '/') + 1;
 604                 confdir = false;
 605                 break;
 606         default:
 607                 /* config in /etc/config */
 608                 filename = uci_config_path(ctx, name);
 609                 confdir = true;
 610                 break;
 611         }
 612
 613         file = uci_open_stream(ctx, filename, SEEK_SET, false, false);
 614         ctx->errno = 0;
 615         UCI_TRAP_SAVE(ctx, done);
 616         UCI_INTERNAL(uci_import, ctx, file, name, package, true);
 617         UCI_TRAP_RESTORE(ctx);
 618
 619         if (*package) {
 620                 (*package)->path = filename;
 621                 (*package)->confdir = confdir;
 622                 uci_load_history(ctx, *package, false);
 623         }
 624
 625 done:
 626         uci_close_stream(file);
 627         return ctx->errno;
 628 }
 629
 630 int uci_commit(struct uci_context *ctx, struct uci_package **package, bool overwrite)
 631 {
 632         struct uci_package *p;
 633         FILE *f = NULL;
 634         char *name = NULL;
 635         char *path = NULL;
 636
 637         UCI_HANDLE_ERR(ctx);
 638         UCI_ASSERT(ctx, package != NULL);
 639         p = *package;
 640
 641         UCI_ASSERT(ctx, p != NULL);
 642         if (!p->path) {
 643                 if (overwrite)
 644                         p->path = uci_config_path(ctx, p->e.name);
 645                 else
 646                         UCI_THROW(ctx, UCI_ERR_INVAL);
 647         }
 648
 649
 650         /* open the config file for writing now, so that it is locked */
 651         f = uci_open_stream(ctx, p->path, SEEK_SET, true, true);
 652
 653         /* flush unsaved changes and reload from history file */
 654         UCI_TRAP_SAVE(ctx, done);
 655         if (p->confdir) {
 656                 if (!overwrite) {
 657                         name = uci_strdup(ctx, p->e.name);
 658                         path = uci_strdup(ctx, p->path);
 659                         /* dump our own changes to the history file */
 660                         if (!uci_list_empty(&p->history))
 661                                 UCI_INTERNAL(uci_save, ctx, p);
 662
 663                         /*
 664                          * other processes might have modified the config
 665                          * as well. dump and reload
 666                          */
 667                         uci_free_package(&p);
 668                         uci_file_cleanup(ctx);
 669                         UCI_INTERNAL(uci_import, ctx, f, name, &p, true);
 670
 671                         p->path = path;
 672                         p->confdir = true;
 673                         *package = p;
 674
 675                         /* freed together with the uci_package */
 676                         path = NULL;
 677
 678                         /* check for updated history, flush */
 679                         uci_load_history(ctx, p, true);
 680                 } else {
 681                         /* flush history */
 682                         uci_load_history(ctx, NULL, true);
 683                 }
 684         }
 685
 686         rewind(f);
 687         ftruncate(fileno(f), 0);
 688
 689         uci_export(ctx, f, p, false);
 690         UCI_TRAP_RESTORE(ctx);
 691
 692 done:
 693         if (name)
 694                 free(name);
 695         if (path)
 696                 free(path);
 697         uci_close_stream(f);
 698         if (ctx->errno)
 699                 UCI_THROW(ctx, ctx->errno);
 700
 701         return 0;
 702 }
 703
 704
 705 /*
 706  * This function returns the filename by returning the string
 707  * after the last '/' character. By checking for a non-'\0'
 708  * character afterwards, directories are ignored (glob marks
 709  * those with a trailing '/'
 710  */
 711 static inline char *get_filename(char *path)
 712 {
 713         char *p;
 714
 715         p = strrchr(path, '/');
 716         p++;
 717         if (!*p)
 718                 return NULL;
 719         return p;
 720 }
 721
 722 int uci_list_configs(struct uci_context *ctx, char ***list)
 723 {
 724         char **configs;
 725         glob_t globbuf;
 726         int size, i;
 727         char *buf;
 728         char *dir;
 729
 730         UCI_HANDLE_ERR(ctx);
 731
 732         dir = uci_malloc(ctx, strlen(ctx->confdir) + 1 + sizeof("/*"));
 733         sprintf(dir, "%s/*", ctx->confdir);
 734         if (glob(dir, GLOB_MARK, NULL, &globbuf) != 0)
 735                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 736
 737         size = sizeof(char *) * (globbuf.gl_pathc + 1);
 738         for(i = 0; i < globbuf.gl_pathc; i++) {
 739                 char *p;
 740
 741                 p = get_filename(globbuf.gl_pathv[i]);
 742                 if (!p)
 743                         continue;
 744
 745                 size += strlen(p) + 1;
 746         }
 747
 748         configs = uci_malloc(ctx, size);
 749         buf = (char *) &configs[globbuf.gl_pathc + 1];
 750         for(i = 0; i < globbuf.gl_pathc; i++) {
 751                 char *p;
 752
 753                 p = get_filename(globbuf.gl_pathv[i]);
 754                 if (!p)
 755                         continue;
 756
 757                 configs[i] = buf;
 758                 strcpy(buf, p);
 759                 buf += strlen(buf) + 1;
 760         }
 761         *list = configs;
 762         free(dir);
 763
 764         return 0;
 765 }
 766