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