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 #include <glob.h>
  28
  29 static struct uci_backend uci_file_backend;
  30
  31 /*
  32  * verify that the end of the line or command is reached.
  33  * throw an error if extra arguments are given on the command line
  34  */
  35 static void assert_eol(struct uci_context *ctx, char **str)
  36 {
  37         char *tmp;
  38
  39         skip_whitespace(ctx, str);
  40         tmp = next_arg(ctx, str, false, false);
  41         if (*tmp && (ctx->flags & UCI_FLAG_STRICT))
  42                 uci_parse_error(ctx, *str, "too many arguments");
  43 }
  44
  45 /*
  46  * switch to a different config, either triggered by uci_load, or by a
  47  * 'package <...>' statement in the import file
  48  */
  49 static void uci_switch_config(struct uci_context *ctx)
  50 {
  51         struct uci_parse_context *pctx;
  52         struct uci_element *e;
  53         const char *name;
  54
  55         pctx = ctx->pctx;
  56         name = pctx->name;
  57
  58         /* add the last config to main config file list */
  59         if (pctx->package) {
  60                 pctx->package->backend = ctx->backend;
  61                 uci_list_add(&ctx->root, &pctx->package->e.list);
  62
  63                 pctx->package = NULL;
  64                 pctx->section = NULL;
  65         }
  66
  67         if (!name)
  68                 return;
  69
  70         /*
  71          * if an older config under the same name exists, unload it
  72          * ignore errors here, e.g. if the config was not found
  73          */
  74         e = uci_lookup_list(&ctx->root, name);
  75         if (e)
  76                 UCI_THROW(ctx, UCI_ERR_DUPLICATE);
  77         pctx->package = uci_alloc_package(ctx, name);
  78 }
  79
  80 /*
  81  * parse the 'package' uci command (next config package)
  82  */
  83 static void uci_parse_package(struct uci_context *ctx, char **str, bool single)
  84 {
  85         char *name = NULL;
  86
  87         /* command string null-terminated by strtok */
  88         *str += strlen(*str) + 1;
  89
  90         name = next_arg(ctx, str, true, true);
  91         assert_eol(ctx, str);
  92         if (single)
  93                 return;
  94
  95         ctx->pctx->name = name;
  96         uci_switch_config(ctx);
  97 }
  98
  99 /*
 100  * parse the 'config' uci command (open a section)
 101  */
 102 static void uci_parse_config(struct uci_context *ctx, char **str)
 103 {
 104         struct uci_parse_context *pctx = ctx->pctx;
 105         struct uci_element *e;
 106         struct uci_ptr ptr;
 107         char *name = NULL;
 108         char *type = NULL;
 109
 110         uci_fixup_section(ctx, ctx->pctx->section);
 111         if (!ctx->pctx->package) {
 112                 if (!ctx->pctx->name)
 113                         uci_parse_error(ctx, *str, "attempting to import a file without a package name");
 114
 115                 uci_switch_config(ctx);
 116         }
 117
 118         /* command string null-terminated by strtok */
 119         *str += strlen(*str) + 1;
 120
 121         type = next_arg(ctx, str, true, false);
 122         if (!uci_validate_str(type, false))
 123                 uci_parse_error(ctx, type, "invalid character in field");
 124         name = next_arg(ctx, str, false, true);
 125         assert_eol(ctx, str);
 126
 127         if (!name) {
 128                 ctx->internal = !pctx->merge;
 129                 UCI_NESTED(uci_add_section, ctx, pctx->package, type, &pctx->section);
 130         } else {
 131                 UCI_NESTED(uci_fill_ptr, ctx, &ptr, &pctx->package->e, false);
 132                 e = uci_lookup_list(&pctx->package->sections, name);
 133                 if (e)
 134                         ptr.s = uci_to_section(e);
 135                 ptr.section = name;
 136                 ptr.value = type;
 137
 138                 ctx->internal = !pctx->merge;
 139                 UCI_NESTED(uci_set, ctx, &ptr);
 140                 pctx->section = uci_to_section(ptr.last);
 141         }
 142 }
 143
 144 /*
 145  * parse the 'option' uci command (open a value)
 146  */
 147 static void uci_parse_option(struct uci_context *ctx, char **str, bool list)
 148 {
 149         struct uci_parse_context *pctx = ctx->pctx;
 150         struct uci_element *e;
 151         struct uci_ptr ptr;
 152         char *name = NULL;
 153         char *value = NULL;
 154
 155         if (!pctx->section)
 156                 uci_parse_error(ctx, *str, "option/list command found before the first section");
 157
 158         /* command string null-terminated by strtok */
 159         *str += strlen(*str) + 1;
 160
 161         name = next_arg(ctx, str, true, true);
 162         value = next_arg(ctx, str, false, false);
 163         assert_eol(ctx, str);
 164
 165         UCI_NESTED(uci_fill_ptr, ctx, &ptr, &pctx->section->e, false);
 166         e = uci_lookup_list(&pctx->section->options, name);
 167         if (e)
 168                 ptr.o = uci_to_option(e);
 169         ptr.option = name;
 170         ptr.value = value;
 171
 172         ctx->internal = !pctx->merge;
 173         if (list)
 174                 UCI_NESTED(uci_add_list, ctx, &ptr);
 175         else
 176                 UCI_NESTED(uci_set, ctx, &ptr);
 177 }
 178
 179 /*
 180  * parse a complete input line, split up combined commands by ';'
 181  */
 182 static void uci_parse_line(struct uci_context *ctx, bool single)
 183 {
 184         struct uci_parse_context *pctx = ctx->pctx;
 185         char *word, *brk;
 186
 187         word = pctx->buf;
 188         do {
 189                 brk = NULL;
 190                 word = strtok_r(word, " \t", &brk);
 191                 if (!word)
 192                         return;
 193
 194                 switch(word[0]) {
 195                         case 0:
 196                         case '#':
 197                                 return;
 198                         case 'p':
 199                                 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
 200                                         uci_parse_package(ctx, &word, single);
 201                                 else
 202                                         goto invalid;
 203                                 break;
 204                         case 'c':
 205                                 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
 206                                         uci_parse_config(ctx, &word);
 207                                 else
 208                                         goto invalid;
 209                                 break;
 210                         case 'o':
 211                                 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
 212                                         uci_parse_option(ctx, &word, false);
 213                                 else
 214                                         goto invalid;
 215                                 break;
 216                         case 'l':
 217                                 if ((word[1] == 0) || !strcmp(word + 1, "ist"))
 218                                         uci_parse_option(ctx, &word, true);
 219                                 else
 220                                         goto invalid;
 221                                 break;
 222                         default:
 223                                 goto invalid;
 224                 }
 225                 continue;
 226 invalid:
 227                 uci_parse_error(ctx, word, "invalid command");
 228         } while (1);
 229 }
 230
 231 /* max number of characters that escaping adds to the string */
 232 #define UCI_QUOTE_ESCAPE        "'\\''"
 233
 234 /*
 235  * escape an uci string for export
 236  */
 237 static char *uci_escape(struct uci_context *ctx, const char *str)
 238 {
 239         const char *end;
 240         int ofs = 0;
 241
 242         if (!ctx->buf) {
 243                 ctx->bufsz = LINEBUF;
 244                 ctx->buf = malloc(LINEBUF);
 245         }
 246
 247         while (1) {
 248                 int len;
 249
 250                 end = strchr(str, '\'');
 251                 if (!end)
 252                         end = str + strlen(str);
 253                 len = end - str;
 254
 255                 /* make sure that we have enough room in the buffer */
 256                 while (ofs + len + sizeof(UCI_QUOTE_ESCAPE) + 1 > ctx->bufsz) {
 257                         ctx->bufsz *= 2;
 258                         ctx->buf = uci_realloc(ctx, ctx->buf, ctx->bufsz);
 259                 }
 260
 261                 /* copy the string until the character before the quote */
 262                 memcpy(&ctx->buf[ofs], str, len);
 263                 ofs += len;
 264
 265                 /* end of string? return the buffer */
 266                 if (*end == 0)
 267                         break;
 268
 269                 memcpy(&ctx->buf[ofs], UCI_QUOTE_ESCAPE, sizeof(UCI_QUOTE_ESCAPE));
 270                 ofs += strlen(&ctx->buf[ofs]);
 271                 str = end + 1;
 272         }
 273
 274         ctx->buf[ofs] = 0;
 275         return ctx->buf;
 276 }
 277
 278 /*
 279  * export a single config package to a file stream
 280  */
 281 static void uci_export_package(struct uci_package *p, FILE *stream, bool header)
 282 {
 283         struct uci_context *ctx = p->ctx;
 284         struct uci_element *s, *o, *i;
 285
 286         if (header)
 287                 fprintf(stream, "package '%s'\n", uci_escape(ctx, p->e.name));
 288         uci_foreach_element(&p->sections, s) {
 289                 struct uci_section *sec = uci_to_section(s);
 290                 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, sec->type));
 291                 if (!sec->anonymous || (ctx->flags & UCI_FLAG_EXPORT_NAME))
 292                         fprintf(stream, " '%s'", uci_escape(ctx, sec->e.name));
 293                 fprintf(stream, "\n");
 294                 uci_foreach_element(&sec->options, o) {
 295                         struct uci_option *opt = uci_to_option(o);
 296                         switch(opt->type) {
 297                         case UCI_TYPE_STRING:
 298                                 fprintf(stream, "\toption '%s'", uci_escape(ctx, opt->e.name));
 299                                 fprintf(stream, " '%s'\n", uci_escape(ctx, opt->v.string));
 300                                 break;
 301                         case UCI_TYPE_LIST:
 302                                 uci_foreach_element(&opt->v.list, i) {
 303                                         fprintf(stream, "\tlist '%s'", uci_escape(ctx, opt->e.name));
 304                                         fprintf(stream, " '%s'\n", uci_escape(ctx, i->name));
 305                                 }
 306                                 break;
 307                         default:
 308                                 fprintf(stream, "\t# unknown type for option '%s'\n", uci_escape(ctx, opt->e.name));
 309                                 break;
 310                         }
 311                 }
 312         }
 313         fprintf(stream, "\n");
 314 }
 315
 316 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header)
 317 {
 318         struct uci_element *e;
 319
 320         UCI_HANDLE_ERR(ctx);
 321         UCI_ASSERT(ctx, stream != NULL);
 322
 323         if (package)
 324                 uci_export_package(package, stream, header);
 325         else {
 326                 uci_foreach_element(&ctx->root, e) {
 327                         uci_export_package(uci_to_package(e), stream, header);
 328                 }
 329         }
 330
 331         return 0;
 332 }
 333
 334 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single)
 335 {
 336         struct uci_parse_context *pctx;
 337         UCI_HANDLE_ERR(ctx);
 338
 339         /* make sure no memory from previous parse attempts is leaked */
 340         uci_cleanup(ctx);
 341
 342         uci_alloc_parse_context(ctx);
 343         pctx = ctx->pctx;
 344         pctx->file = stream;
 345         if (*package && single) {
 346                 pctx->package = *package;
 347                 pctx->merge = true;
 348         }
 349
 350         /*
 351          * If 'name' was supplied, assume that the supplied stream does not contain
 352          * the appropriate 'package <name>' string to specify the config name
 353          * NB: the config file can still override the package name
 354          */
 355         if (name) {
 356                 UCI_ASSERT(ctx, uci_validate_str(name, false));
 357                 pctx->name = name;
 358         }
 359
 360         while (!feof(pctx->file)) {
 361                 uci_getln(ctx, 0);
 362                 UCI_TRAP_SAVE(ctx, error);
 363                 if (pctx->buf[0])
 364                         uci_parse_line(ctx, single);
 365                 UCI_TRAP_RESTORE(ctx);
 366                 continue;
 367 error:
 368                 if (ctx->flags & UCI_FLAG_PERROR)
 369                         uci_perror(ctx, NULL);
 370                 if ((ctx->err != UCI_ERR_PARSE) ||
 371                         (ctx->flags & UCI_FLAG_STRICT))
 372                         UCI_THROW(ctx, ctx->err);
 373         }
 374
 375         uci_fixup_section(ctx, ctx->pctx->section);
 376         if (!pctx->package && name)
 377                 uci_switch_config(ctx);
 378         if (package)
 379                 *package = pctx->package;
 380         if (pctx->merge)
 381                 pctx->package = NULL;
 382
 383         pctx->name = NULL;
 384         uci_switch_config(ctx);
 385
 386         /* no error happened, we can get rid of the parser context now */
 387         uci_cleanup(ctx);
 388
 389         return 0;
 390 }
 391
 392
 393 static char *uci_config_path(struct uci_context *ctx, const char *name)
 394 {
 395         char *filename;
 396
 397         UCI_ASSERT(ctx, uci_validate_str(name, false));
 398         filename = uci_malloc(ctx, strlen(name) + strlen(ctx->confdir) + 2);
 399         sprintf(filename, "%s/%s", ctx->confdir, name);
 400
 401         return filename;
 402 }
 403
 404 void uci_file_commit(struct uci_context *ctx, struct uci_package **package, bool overwrite)
 405 {
 406         struct uci_package *p = *package;
 407         FILE *f = NULL;
 408         char *name = NULL;
 409         char *path = NULL;
 410
 411         if (!p->path) {
 412                 if (overwrite)
 413                         p->path = uci_config_path(ctx, p->e.name);
 414                 else
 415                         UCI_THROW(ctx, UCI_ERR_INVAL);
 416         }
 417
 418         /* open the config file for writing now, so that it is locked */
 419         f = uci_open_stream(ctx, p->path, SEEK_SET, true, true);
 420
 421         /* flush unsaved changes and reload from history file */
 422         UCI_TRAP_SAVE(ctx, done);
 423         if (p->has_history) {
 424                 if (!overwrite) {
 425                         name = uci_strdup(ctx, p->e.name);
 426                         path = uci_strdup(ctx, p->path);
 427                         /* dump our own changes to the history file */
 428                         if (!uci_list_empty(&p->history))
 429                                 UCI_INTERNAL(uci_save, ctx, p);
 430
 431                         /*
 432                          * other processes might have modified the config
 433                          * as well. dump and reload
 434                          */
 435                         uci_free_package(&p);
 436                         uci_cleanup(ctx);
 437                         UCI_INTERNAL(uci_import, ctx, f, name, &p, true);
 438
 439                         p->path = path;
 440                         p->has_history = true;
 441                         *package = p;
 442
 443                         /* freed together with the uci_package */
 444                         path = NULL;
 445
 446                         /* check for updated history, flush */
 447                         if (!uci_load_history(ctx, p, true))
 448                                 goto done;
 449                 } else {
 450                         /* flush history */
 451                         if (!uci_load_history(ctx, NULL, true))
 452                                 goto done;
 453                 }
 454         }
 455
 456         rewind(f);
 457         ftruncate(fileno(f), 0);
 458
 459         uci_export(ctx, f, p, false);
 460         UCI_TRAP_RESTORE(ctx);
 461
 462 done:
 463         if (name)
 464                 free(name);
 465         if (path)
 466                 free(path);
 467         uci_close_stream(f);
 468         if (ctx->err)
 469                 UCI_THROW(ctx, ctx->err);
 470 }
 471
 472
 473 /*
 474  * This function returns the filename by returning the string
 475  * after the last '/' character. By checking for a non-'\0'
 476  * character afterwards, directories are ignored (glob marks
 477  * those with a trailing '/'
 478  */
 479 static inline char *get_filename(char *path)
 480 {
 481         char *p;
 482
 483         p = strrchr(path, '/');
 484         p++;
 485         if (!*p)
 486                 return NULL;
 487         return p;
 488 }
 489
 490 static char **uci_list_config_files(struct uci_context *ctx)
 491 {
 492         char **configs;
 493         glob_t globbuf;
 494         int size, i;
 495         char *buf;
 496         char *dir;
 497
 498         dir = uci_malloc(ctx, strlen(ctx->confdir) + 1 + sizeof("/*"));
 499         sprintf(dir, "%s/*", ctx->confdir);
 500         if (glob(dir, GLOB_MARK, NULL, &globbuf) != 0)
 501                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 502
 503         size = sizeof(char *) * (globbuf.gl_pathc + 1);
 504         for(i = 0; i < globbuf.gl_pathc; i++) {
 505                 char *p;
 506
 507                 p = get_filename(globbuf.gl_pathv[i]);
 508                 if (!p)
 509                         continue;
 510
 511                 size += strlen(p) + 1;
 512         }
 513
 514         configs = uci_malloc(ctx, size);
 515         buf = (char *) &configs[globbuf.gl_pathc + 1];
 516         for(i = 0; i < globbuf.gl_pathc; i++) {
 517                 char *p;
 518
 519                 p = get_filename(globbuf.gl_pathv[i]);
 520                 if (!p)
 521                         continue;
 522
 523                 if (!uci_validate_name(p))
 524                         continue;
 525
 526                 configs[i] = buf;
 527                 strcpy(buf, p);
 528                 buf += strlen(buf) + 1;
 529         }
 530         free(dir);
 531         return configs;
 532 }
 533
 534 static struct uci_package *uci_file_load(struct uci_context *ctx, const char *name)
 535 {
 536         struct uci_package *package = NULL;
 537         char *filename;
 538         bool confdir;
 539         FILE *file = NULL;
 540
 541         switch (name[0]) {
 542         case '.':
 543                 /* relative path outside of /etc/config */
 544                 if (name[1] != '/')
 545                         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 546                 /* fall through */
 547         case '/':
 548                 /* absolute path outside of /etc/config */
 549                 filename = uci_strdup(ctx, name);
 550                 name = strrchr(name, '/') + 1;
 551                 confdir = false;
 552                 break;
 553         default:
 554                 /* config in /etc/config */
 555                 filename = uci_config_path(ctx, name);
 556                 confdir = true;
 557                 break;
 558         }
 559
 560         file = uci_open_stream(ctx, filename, SEEK_SET, false, false);
 561         ctx->err = 0;
 562         UCI_TRAP_SAVE(ctx, done);
 563         UCI_INTERNAL(uci_import, ctx, file, name, &package, true);
 564         UCI_TRAP_RESTORE(ctx);
 565
 566         if (package) {
 567                 package->path = filename;
 568                 package->has_history = confdir;
 569                 uci_load_history(ctx, package, false);
 570         }
 571
 572 done:
 573         uci_close_stream(file);
 574         if (ctx->err)
 575                 UCI_THROW(ctx, ctx->err);
 576         return package;
 577 }
 578
 579 static UCI_BACKEND(uci_file_backend, "file",
 580         .load = uci_file_load,
 581         .commit = uci_file_commit,
 582         .list_configs = uci_list_config_files,
 583 );