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, true);
 346         name = next_arg(ctx, str, false, true);
 347         assert_eol(ctx, str);
 348
 349         if (pctx->merge) {
 350                 UCI_TRAP_SAVE(ctx, error);
 351                 uci_set(ctx, pctx->package, name, NULL, type);
 352                 UCI_TRAP_RESTORE(ctx);
 353                 return;
 354 error:
 355                 UCI_THROW(ctx, ctx->errno);
 356         } else
 357                 pctx->section = uci_alloc_section(pctx->package, type, name);
 358 }
 359
 360 /*
 361  * parse the 'option' uci command (open a value)
 362  */
 363 static void uci_parse_option(struct uci_context *ctx, char **str)
 364 {
 365         struct uci_parse_context *pctx = ctx->pctx;
 366         char *name = NULL;
 367         char *value = NULL;
 368
 369         if (!pctx->section)
 370                 uci_parse_error(ctx, *str, "option command found before the first section");
 371
 372         /* command string null-terminated by strtok */
 373         *str += strlen(*str) + 1;
 374
 375         name = next_arg(ctx, str, true, true);
 376         value = next_arg(ctx, str, true, false);
 377         assert_eol(ctx, str);
 378
 379         if (pctx->merge) {
 380                 UCI_TRAP_SAVE(ctx, error);
 381                 uci_set(ctx, pctx->package, pctx->section->e.name, name, value);
 382                 UCI_TRAP_RESTORE(ctx);
 383                 return;
 384 error:
 385                 UCI_THROW(ctx, ctx->errno);
 386         } else
 387                 uci_alloc_option(pctx->section, name, value);
 388 }
 389
 390
 391 /*
 392  * parse a complete input line, split up combined commands by ';'
 393  */
 394 static void uci_parse_line(struct uci_context *ctx, bool single)
 395 {
 396         struct uci_parse_context *pctx = ctx->pctx;
 397         char *word, *brk = NULL;
 398
 399         for (word = strtok_r(pctx->buf, ";", &brk);
 400                  word;
 401                  word = strtok_r(NULL, ";", &brk)) {
 402
 403                 char *pbrk = NULL;
 404                 word = strtok_r(word, " \t", &pbrk);
 405
 406                 if (!word)
 407                         continue;
 408
 409                 switch(word[0]) {
 410                         case '#':
 411                                 return;
 412                         case 'p':
 413                                 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
 414                                         uci_parse_package(ctx, &word, single);
 415                                 break;
 416                         case 'c':
 417                                 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
 418                                         uci_parse_config(ctx, &word);
 419                                 break;
 420                         case 'o':
 421                                 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
 422                                         uci_parse_option(ctx, &word);
 423                                 break;
 424                         default:
 425                                 uci_parse_error(ctx, word, "unterminated command");
 426                                 break;
 427                 }
 428         }
 429 }
 430
 431 /* max number of characters that escaping adds to the string */
 432 #define UCI_QUOTE_ESCAPE        "'\\''"
 433
 434 /*
 435  * escape an uci string for export
 436  */
 437 static char *uci_escape(struct uci_context *ctx, char *str)
 438 {
 439         char *s, *p;
 440         int pos = 0;
 441
 442         if (!ctx->buf) {
 443                 ctx->bufsz = LINEBUF;
 444                 ctx->buf = malloc(LINEBUF);
 445         }
 446
 447         s = str;
 448         p = strchr(str, '\'');
 449         if (!p)
 450                 return str;
 451
 452         do {
 453                 int len = p - s;
 454                 if (len > 0) {
 455                         if (p + sizeof(UCI_QUOTE_ESCAPE) - str >= ctx->bufsz) {
 456                                 ctx->bufsz *= 2;
 457                                 ctx->buf = realloc(ctx->buf, ctx->bufsz);
 458                                 if (!ctx->buf)
 459                                         UCI_THROW(ctx, UCI_ERR_MEM);
 460                         }
 461                         memcpy(&ctx->buf[pos], s, len);
 462                         pos += len;
 463                 }
 464                 strcpy(&ctx->buf[pos], UCI_QUOTE_ESCAPE);
 465                 pos += sizeof(UCI_QUOTE_ESCAPE);
 466                 s = p + 1;
 467         } while ((p = strchr(s, '\'')));
 468
 469         return ctx->buf;
 470 }
 471
 472
 473 /*
 474  * export a single config package to a file stream
 475  */
 476 static void uci_export_package(struct uci_package *p, FILE *stream, bool header)
 477 {
 478         struct uci_context *ctx = p->ctx;
 479         struct uci_element *s, *o;
 480
 481         if (header)
 482                 fprintf(stream, "package '%s'\n", uci_escape(ctx, p->e.name));
 483         uci_foreach_element(&p->sections, s) {
 484                 struct uci_section *sec = uci_to_section(s);
 485                 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, sec->type));
 486                 if (!sec->anonymous || (ctx->flags & UCI_FLAG_EXPORT_NAME))
 487                         fprintf(stream, " '%s'", uci_escape(ctx, sec->e.name));
 488                 fprintf(stream, "\n");
 489                 uci_foreach_element(&sec->options, o) {
 490                         struct uci_option *opt = uci_to_option(o);
 491                         fprintf(stream, "\toption '%s'", uci_escape(ctx, opt->e.name));
 492                         fprintf(stream, " '%s'\n", uci_escape(ctx, opt->value));
 493                 }
 494         }
 495         fprintf(stream, "\n");
 496 }
 497
 498 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header)
 499 {
 500         struct uci_element *e;
 501
 502         UCI_HANDLE_ERR(ctx);
 503         UCI_ASSERT(ctx, stream != NULL);
 504
 505         if (package)
 506                 uci_export_package(package, stream, header);
 507         else {
 508                 uci_foreach_element(&ctx->root, e) {
 509                         uci_export_package(uci_to_package(e), stream, header);
 510                 }
 511         }
 512
 513         return 0;
 514 }
 515
 516 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single)
 517 {
 518         struct uci_parse_context *pctx;
 519         UCI_HANDLE_ERR(ctx);
 520
 521         /* make sure no memory from previous parse attempts is leaked */
 522         uci_file_cleanup(ctx);
 523
 524         pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 525         ctx->pctx = pctx;
 526         pctx->file = stream;
 527         if (*package && single) {
 528                 pctx->package = *package;
 529                 pctx->merge = true;
 530         }
 531
 532         /*
 533          * If 'name' was supplied, assume that the supplied stream does not contain
 534          * the appropriate 'package <name>' string to specify the config name
 535          * NB: the config file can still override the package name
 536          */
 537         if (name) {
 538                 UCI_ASSERT(ctx, uci_validate_name(name));
 539                 pctx->name = name;
 540         }
 541
 542         while (!feof(pctx->file)) {
 543                 uci_getln(ctx, 0);
 544                 UCI_TRAP_SAVE(ctx, error);
 545                 if (pctx->buf[0])
 546                         uci_parse_line(ctx, single);
 547                 UCI_TRAP_RESTORE(ctx);
 548                 continue;
 549 error:
 550                 if (ctx->flags & UCI_FLAG_PERROR)
 551                         uci_perror(ctx, NULL);
 552                 if ((ctx->errno != UCI_ERR_PARSE) ||
 553                         (ctx->flags & UCI_FLAG_STRICT))
 554                         UCI_THROW(ctx, ctx->errno);
 555         }
 556
 557         uci_fixup_section(ctx, ctx->pctx->section);
 558         if (package)
 559                 *package = pctx->package;
 560         if (pctx->merge)
 561                 pctx->package = NULL;
 562
 563         pctx->name = NULL;
 564         uci_switch_config(ctx);
 565
 566         /* no error happened, we can get rid of the parser context now */
 567         uci_file_cleanup(ctx);
 568
 569         return 0;
 570 }
 571
 572
 573 static char *uci_config_path(struct uci_context *ctx, const char *name)
 574 {
 575         char *filename;
 576
 577         UCI_ASSERT(ctx, uci_validate_name(name));
 578         filename = uci_malloc(ctx, strlen(name) + strlen(ctx->confdir) + 2);
 579         sprintf(filename, "%s/%s", ctx->confdir, name);
 580
 581         return filename;
 582 }
 583
 584 int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package)
 585 {
 586         char *filename;
 587         bool confdir;
 588         FILE *file = NULL;
 589
 590         UCI_HANDLE_ERR(ctx);
 591
 592         switch (name[0]) {
 593         case '.':
 594                 /* relative path outside of /etc/config */
 595                 if (name[1] != '/')
 596                         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 597                 /* fall through */
 598         case '/':
 599                 /* absolute path outside of /etc/config */
 600                 filename = uci_strdup(ctx, name);
 601                 name = strrchr(name, '/') + 1;
 602                 confdir = false;
 603                 break;
 604         default:
 605                 /* config in /etc/config */
 606                 filename = uci_config_path(ctx, name);
 607                 confdir = true;
 608                 break;
 609         }
 610
 611         file = uci_open_stream(ctx, filename, SEEK_SET, false, false);
 612         ctx->errno = 0;
 613         UCI_TRAP_SAVE(ctx, done);
 614         UCI_INTERNAL(uci_import, ctx, file, name, package, true);
 615         UCI_TRAP_RESTORE(ctx);
 616
 617         if (*package) {
 618                 (*package)->path = filename;
 619                 (*package)->confdir = confdir;
 620                 uci_load_history(ctx, *package, false);
 621         }
 622
 623 done:
 624         uci_close_stream(file);
 625         return ctx->errno;
 626 }
 627
 628 int uci_commit(struct uci_context *ctx, struct uci_package **package, bool overwrite)
 629 {
 630         struct uci_package *p;
 631         FILE *f = NULL;
 632         char *name = NULL;
 633         char *path = NULL;
 634
 635         UCI_HANDLE_ERR(ctx);
 636         UCI_ASSERT(ctx, package != NULL);
 637         p = *package;
 638
 639         UCI_ASSERT(ctx, p != NULL);
 640         if (!p->path) {
 641                 if (overwrite)
 642                         p->path = uci_config_path(ctx, p->e.name);
 643                 else
 644                         UCI_THROW(ctx, UCI_ERR_INVAL);
 645         }
 646
 647
 648         /* open the config file for writing now, so that it is locked */
 649         f = uci_open_stream(ctx, p->path, SEEK_SET, true, true);
 650
 651         /* flush unsaved changes and reload from history file */
 652         UCI_TRAP_SAVE(ctx, done);
 653         if (p->confdir) {
 654                 if (!overwrite) {
 655                         name = uci_strdup(ctx, p->e.name);
 656                         path = uci_strdup(ctx, p->path);
 657                         /* dump our own changes to the history file */
 658                         if (!uci_list_empty(&p->history))
 659                                 UCI_INTERNAL(uci_save, ctx, p);
 660
 661                         /*
 662                          * other processes might have modified the config
 663                          * as well. dump and reload
 664                          */
 665                         uci_free_package(&p);
 666                         uci_file_cleanup(ctx);
 667                         UCI_INTERNAL(uci_import, ctx, f, name, &p, true);
 668
 669                         p->path = path;
 670                         p->confdir = true;
 671                         *package = p;
 672
 673                         /* freed together with the uci_package */
 674                         path = NULL;
 675
 676                         /* check for updated history, just in case */
 677                         uci_load_history(ctx, p, true);
 678                 } else {
 679                         /* flush history */
 680                         uci_load_history(ctx, NULL, true);
 681                 }
 682         }
 683
 684         rewind(f);
 685         ftruncate(fileno(f), 0);
 686
 687         uci_export(ctx, f, p, false);
 688         UCI_TRAP_RESTORE(ctx);
 689
 690 done:
 691         if (name)
 692                 free(name);
 693         if (path)
 694                 free(path);
 695         uci_close_stream(f);
 696         if (ctx->errno)
 697                 UCI_THROW(ctx, ctx->errno);
 698
 699         return 0;
 700 }
 701
 702
 703 /*
 704  * This function returns the filename by returning the string
 705  * after the last '/' character. By checking for a non-'\0'
 706  * character afterwards, directories are ignored (glob marks
 707  * those with a trailing '/'
 708  */
 709 static inline char *get_filename(char *path)
 710 {
 711         char *p;
 712
 713         p = strrchr(path, '/');
 714         p++;
 715         if (!*p)
 716                 return NULL;
 717         return p;
 718 }
 719
 720 int uci_list_configs(struct uci_context *ctx, char ***list)
 721 {
 722         char **configs;
 723         glob_t globbuf;
 724         int size, i;
 725         char *buf;
 726         char *dir;
 727
 728         UCI_HANDLE_ERR(ctx);
 729
 730         dir = uci_malloc(ctx, strlen(ctx->confdir) + 1 + sizeof("/*"));
 731         sprintf(dir, "%s/*", ctx->confdir);
 732         if (glob(dir, GLOB_MARK, NULL, &globbuf) != 0)
 733                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 734
 735         size = sizeof(char *) * (globbuf.gl_pathc + 1);
 736         for(i = 0; i < globbuf.gl_pathc; i++) {
 737                 char *p;
 738
 739                 p = get_filename(globbuf.gl_pathv[i]);
 740                 if (!p)
 741                         continue;
 742
 743                 size += strlen(p) + 1;
 744         }
 745
 746         configs = uci_malloc(ctx, size);
 747         buf = (char *) &configs[globbuf.gl_pathc + 1];
 748         for(i = 0; i < globbuf.gl_pathc; i++) {
 749                 char *p;
 750
 751                 p = get_filename(globbuf.gl_pathv[i]);
 752                 if (!p)
 753                         continue;
 754
 755                 configs[i] = buf;
 756                 strcpy(buf, p);
 757                 buf += strlen(buf) + 1;
 758         }
 759         *list = configs;
 760         free(dir);
 761
 762         return 0;
 763 }
 764