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         char *name = NULL;
 106         char *type = NULL;
 107
 108         uci_fixup_section(ctx, ctx->pctx->section);
 109         if (!ctx->pctx->package) {
 110                 if (!ctx->pctx->name)
 111                         uci_parse_error(ctx, *str, "attempting to import a file without a package name");
 112
 113                 uci_switch_config(ctx);
 114         }
 115
 116         /* command string null-terminated by strtok */
 117         *str += strlen(*str) + 1;
 118
 119         type = next_arg(ctx, str, true, false);
 120         if (!uci_validate_str(type, false))
 121                 uci_parse_error(ctx, type, "invalid character in field");
 122         name = next_arg(ctx, str, false, true);
 123         assert_eol(ctx, str);
 124
 125         if (pctx->merge) {
 126                 UCI_NESTED(uci_set, ctx, pctx->package, name, NULL, type, NULL);
 127         } else
 128                 pctx->section = uci_alloc_section(pctx->package, type, name);
 129 }
 130
 131 /*
 132  * parse the 'option' uci command (open a value)
 133  */
 134 static void uci_parse_option(struct uci_context *ctx, char **str)
 135 {
 136         struct uci_parse_context *pctx = ctx->pctx;
 137         char *name = NULL;
 138         char *value = NULL;
 139
 140         if (!pctx->section)
 141                 uci_parse_error(ctx, *str, "option command found before the first section");
 142
 143         /* command string null-terminated by strtok */
 144         *str += strlen(*str) + 1;
 145
 146         name = next_arg(ctx, str, true, true);
 147         value = next_arg(ctx, str, false, false);
 148         assert_eol(ctx, str);
 149
 150         if (pctx->merge) {
 151                 UCI_NESTED(uci_set, ctx, pctx->package, pctx->section->e.name, name, value, NULL);
 152         } else
 153                 uci_alloc_option(pctx->section, name, value);
 154 }
 155
 156 static void uci_parse_list(struct uci_context *ctx, char **str)
 157 {
 158         struct uci_parse_context *pctx = ctx->pctx;
 159         struct uci_ptr ptr;
 160         char *name = NULL;
 161         char *value = NULL;
 162
 163         if (!pctx->section)
 164                 uci_parse_error(ctx, *str, "list command found before the first section");
 165
 166         /* command string null-terminated by strtok */
 167         *str += strlen(*str) + 1;
 168
 169         name = next_arg(ctx, str, true, true);
 170         value = next_arg(ctx, str, false, false);
 171         assert_eol(ctx, str);
 172
 173         UCI_NESTED(uci_fill_ptr, ctx, &ptr, &pctx->section->e, false);
 174         ptr.option = name;
 175         ptr.value = value;
 176
 177         UCI_INTERNAL(uci_lookup_ptr, ctx, &ptr, NULL, false);
 178
 179         ctx->internal = !pctx->merge;
 180         UCI_NESTED(uci_add_list, ctx, &ptr);
 181 }
 182
 183
 184 /*
 185  * parse a complete input line, split up combined commands by ';'
 186  */
 187 static void uci_parse_line(struct uci_context *ctx, bool single)
 188 {
 189         struct uci_parse_context *pctx = ctx->pctx;
 190         char *word, *brk;
 191
 192         word = pctx->buf;
 193         do {
 194                 brk = NULL;
 195                 word = strtok_r(word, " \t", &brk);
 196                 if (!word)
 197                         return;
 198
 199                 switch(word[0]) {
 200                         case 0:
 201                         case '#':
 202                                 return;
 203                         case 'p':
 204                                 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
 205                                         uci_parse_package(ctx, &word, single);
 206                                 else
 207                                         goto invalid;
 208                                 break;
 209                         case 'c':
 210                                 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
 211                                         uci_parse_config(ctx, &word);
 212                                 else
 213                                         goto invalid;
 214                                 break;
 215                         case 'o':
 216                                 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
 217                                         uci_parse_option(ctx, &word);
 218                                 else
 219                                         goto invalid;
 220                                 break;
 221                         case 'l':
 222                                 if ((word[1] == 0) || !strcmp(word + 1, "ist"))
 223                                         uci_parse_list(ctx, &word);
 224                                 else
 225                                         goto invalid;
 226                                 break;
 227                         default:
 228                                 goto invalid;
 229                 }
 230                 continue;
 231 invalid:
 232                 uci_parse_error(ctx, word, "invalid command");
 233         } while (1);
 234 }
 235
 236 /* max number of characters that escaping adds to the string */
 237 #define UCI_QUOTE_ESCAPE        "'\\''"
 238
 239 /*
 240  * escape an uci string for export
 241  */
 242 static char *uci_escape(struct uci_context *ctx, const char *str)
 243 {
 244         const char *end;
 245         int ofs = 0;
 246
 247         if (!ctx->buf) {
 248                 ctx->bufsz = LINEBUF;
 249                 ctx->buf = malloc(LINEBUF);
 250         }
 251
 252         while (1) {
 253                 int len;
 254
 255                 end = strchr(str, '\'');
 256                 if (!end)
 257                         end = str + strlen(str);
 258                 len = end - str;
 259
 260                 /* make sure that we have enough room in the buffer */
 261                 while (ofs + len + sizeof(UCI_QUOTE_ESCAPE) + 1 > ctx->bufsz) {
 262                         ctx->bufsz *= 2;
 263                         ctx->buf = uci_realloc(ctx, ctx->buf, ctx->bufsz);
 264                 }
 265
 266                 /* copy the string until the character before the quote */
 267                 memcpy(&ctx->buf[ofs], str, len);
 268                 ofs += len;
 269
 270                 /* end of string? return the buffer */
 271                 if (*end == 0)
 272                         break;
 273
 274                 memcpy(&ctx->buf[ofs], UCI_QUOTE_ESCAPE, sizeof(UCI_QUOTE_ESCAPE));
 275                 ofs += strlen(&ctx->buf[ofs]);
 276                 str = end + 1;
 277         }
 278
 279         ctx->buf[ofs] = 0;
 280         return ctx->buf;
 281 }
 282
 283 /*
 284  * export a single config package to a file stream
 285  */
 286 static void uci_export_package(struct uci_package *p, FILE *stream, bool header)
 287 {
 288         struct uci_context *ctx = p->ctx;
 289         struct uci_element *s, *o, *i;
 290
 291         if (header)
 292                 fprintf(stream, "package '%s'\n", uci_escape(ctx, p->e.name));
 293         uci_foreach_element(&p->sections, s) {
 294                 struct uci_section *sec = uci_to_section(s);
 295                 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, sec->type));
 296                 if (!sec->anonymous || (ctx->flags & UCI_FLAG_EXPORT_NAME))
 297                         fprintf(stream, " '%s'", uci_escape(ctx, sec->e.name));
 298                 fprintf(stream, "\n");
 299                 uci_foreach_element(&sec->options, o) {
 300                         struct uci_option *opt = uci_to_option(o);
 301                         switch(opt->type) {
 302                         case UCI_TYPE_STRING:
 303                                 fprintf(stream, "\toption '%s'", uci_escape(ctx, opt->e.name));
 304                                 fprintf(stream, " '%s'\n", uci_escape(ctx, opt->v.string));
 305                                 break;
 306                         case UCI_TYPE_LIST:
 307                                 uci_foreach_element(&opt->v.list, i) {
 308                                         fprintf(stream, "\tlist '%s'", uci_escape(ctx, opt->e.name));
 309                                         fprintf(stream, " '%s'\n", uci_escape(ctx, i->name));
 310                                 }
 311                                 break;
 312                         default:
 313                                 fprintf(stream, "\t# unknown type for option '%s'\n", uci_escape(ctx, opt->e.name));
 314                                 break;
 315                         }
 316                 }
 317         }
 318         fprintf(stream, "\n");
 319 }
 320
 321 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header)
 322 {
 323         struct uci_element *e;
 324
 325         UCI_HANDLE_ERR(ctx);
 326         UCI_ASSERT(ctx, stream != NULL);
 327
 328         if (package)
 329                 uci_export_package(package, stream, header);
 330         else {
 331                 uci_foreach_element(&ctx->root, e) {
 332                         uci_export_package(uci_to_package(e), stream, header);
 333                 }
 334         }
 335
 336         return 0;
 337 }
 338
 339 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single)
 340 {
 341         struct uci_parse_context *pctx;
 342         UCI_HANDLE_ERR(ctx);
 343
 344         /* make sure no memory from previous parse attempts is leaked */
 345         uci_cleanup(ctx);
 346
 347         uci_alloc_parse_context(ctx);
 348         pctx = ctx->pctx;
 349         pctx->file = stream;
 350         if (*package && single) {
 351                 pctx->package = *package;
 352                 pctx->merge = true;
 353         }
 354
 355         /*
 356          * If 'name' was supplied, assume that the supplied stream does not contain
 357          * the appropriate 'package <name>' string to specify the config name
 358          * NB: the config file can still override the package name
 359          */
 360         if (name) {
 361                 UCI_ASSERT(ctx, uci_validate_str(name, false));
 362                 pctx->name = name;
 363         }
 364
 365         while (!feof(pctx->file)) {
 366                 uci_getln(ctx, 0);
 367                 UCI_TRAP_SAVE(ctx, error);
 368                 if (pctx->buf[0])
 369                         uci_parse_line(ctx, single);
 370                 UCI_TRAP_RESTORE(ctx);
 371                 continue;
 372 error:
 373                 if (ctx->flags & UCI_FLAG_PERROR)
 374                         uci_perror(ctx, NULL);
 375                 if ((ctx->err != UCI_ERR_PARSE) ||
 376                         (ctx->flags & UCI_FLAG_STRICT))
 377                         UCI_THROW(ctx, ctx->err);
 378         }
 379
 380         uci_fixup_section(ctx, ctx->pctx->section);
 381         if (!pctx->package && name)
 382                 uci_switch_config(ctx);
 383         if (package)
 384                 *package = pctx->package;
 385         if (pctx->merge)
 386                 pctx->package = NULL;
 387
 388         pctx->name = NULL;
 389         uci_switch_config(ctx);
 390
 391         /* no error happened, we can get rid of the parser context now */
 392         uci_cleanup(ctx);
 393
 394         return 0;
 395 }
 396
 397
 398 static char *uci_config_path(struct uci_context *ctx, const char *name)
 399 {
 400         char *filename;
 401
 402         UCI_ASSERT(ctx, uci_validate_str(name, false));
 403         filename = uci_malloc(ctx, strlen(name) + strlen(ctx->confdir) + 2);
 404         sprintf(filename, "%s/%s", ctx->confdir, name);
 405
 406         return filename;
 407 }
 408
 409 void uci_file_commit(struct uci_context *ctx, struct uci_package **package, bool overwrite)
 410 {
 411         struct uci_package *p = *package;
 412         FILE *f = NULL;
 413         char *name = NULL;
 414         char *path = NULL;
 415
 416         if (!p->path) {
 417                 if (overwrite)
 418                         p->path = uci_config_path(ctx, p->e.name);
 419                 else
 420                         UCI_THROW(ctx, UCI_ERR_INVAL);
 421         }
 422
 423         /* open the config file for writing now, so that it is locked */
 424         f = uci_open_stream(ctx, p->path, SEEK_SET, true, true);
 425
 426         /* flush unsaved changes and reload from history file */
 427         UCI_TRAP_SAVE(ctx, done);
 428         if (p->has_history) {
 429                 if (!overwrite) {
 430                         name = uci_strdup(ctx, p->e.name);
 431                         path = uci_strdup(ctx, p->path);
 432                         /* dump our own changes to the history file */
 433                         if (!uci_list_empty(&p->history))
 434                                 UCI_INTERNAL(uci_save, ctx, p);
 435
 436                         /*
 437                          * other processes might have modified the config
 438                          * as well. dump and reload
 439                          */
 440                         uci_free_package(&p);
 441                         uci_cleanup(ctx);
 442                         UCI_INTERNAL(uci_import, ctx, f, name, &p, true);
 443
 444                         p->path = path;
 445                         p->has_history = true;
 446                         *package = p;
 447
 448                         /* freed together with the uci_package */
 449                         path = NULL;
 450
 451                         /* check for updated history, flush */
 452                         if (!uci_load_history(ctx, p, true))
 453                                 goto done;
 454                 } else {
 455                         /* flush history */
 456                         if (!uci_load_history(ctx, NULL, true))
 457                                 goto done;
 458                 }
 459         }
 460
 461         rewind(f);
 462         ftruncate(fileno(f), 0);
 463
 464         uci_export(ctx, f, p, false);
 465         UCI_TRAP_RESTORE(ctx);
 466
 467 done:
 468         if (name)
 469                 free(name);
 470         if (path)
 471                 free(path);
 472         uci_close_stream(f);
 473         if (ctx->err)
 474                 UCI_THROW(ctx, ctx->err);
 475 }
 476
 477
 478 /*
 479  * This function returns the filename by returning the string
 480  * after the last '/' character. By checking for a non-'\0'
 481  * character afterwards, directories are ignored (glob marks
 482  * those with a trailing '/'
 483  */
 484 static inline char *get_filename(char *path)
 485 {
 486         char *p;
 487
 488         p = strrchr(path, '/');
 489         p++;
 490         if (!*p)
 491                 return NULL;
 492         return p;
 493 }
 494
 495 static char **uci_list_config_files(struct uci_context *ctx)
 496 {
 497         char **configs;
 498         glob_t globbuf;
 499         int size, i;
 500         char *buf;
 501         char *dir;
 502
 503         dir = uci_malloc(ctx, strlen(ctx->confdir) + 1 + sizeof("/*"));
 504         sprintf(dir, "%s/*", ctx->confdir);
 505         if (glob(dir, GLOB_MARK, NULL, &globbuf) != 0)
 506                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 507
 508         size = sizeof(char *) * (globbuf.gl_pathc + 1);
 509         for(i = 0; i < globbuf.gl_pathc; i++) {
 510                 char *p;
 511
 512                 p = get_filename(globbuf.gl_pathv[i]);
 513                 if (!p)
 514                         continue;
 515
 516                 size += strlen(p) + 1;
 517         }
 518
 519         configs = uci_malloc(ctx, size);
 520         buf = (char *) &configs[globbuf.gl_pathc + 1];
 521         for(i = 0; i < globbuf.gl_pathc; i++) {
 522                 char *p;
 523
 524                 p = get_filename(globbuf.gl_pathv[i]);
 525                 if (!p)
 526                         continue;
 527
 528                 if (!uci_validate_name(p))
 529                         continue;
 530
 531                 configs[i] = buf;
 532                 strcpy(buf, p);
 533                 buf += strlen(buf) + 1;
 534         }
 535         free(dir);
 536         return configs;
 537 }
 538
 539 static struct uci_package *uci_file_load(struct uci_context *ctx, const char *name)
 540 {
 541         struct uci_package *package = NULL;
 542         char *filename;
 543         bool confdir;
 544         FILE *file = NULL;
 545
 546         switch (name[0]) {
 547         case '.':
 548                 /* relative path outside of /etc/config */
 549                 if (name[1] != '/')
 550                         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 551                 /* fall through */
 552         case '/':
 553                 /* absolute path outside of /etc/config */
 554                 filename = uci_strdup(ctx, name);
 555                 name = strrchr(name, '/') + 1;
 556                 confdir = false;
 557                 break;
 558         default:
 559                 /* config in /etc/config */
 560                 filename = uci_config_path(ctx, name);
 561                 confdir = true;
 562                 break;
 563         }
 564
 565         file = uci_open_stream(ctx, filename, SEEK_SET, false, false);
 566         ctx->err = 0;
 567         UCI_TRAP_SAVE(ctx, done);
 568         UCI_INTERNAL(uci_import, ctx, file, name, &package, true);
 569         UCI_TRAP_RESTORE(ctx);
 570
 571         if (package) {
 572                 package->path = filename;
 573                 package->has_history = confdir;
 574                 uci_load_history(ctx, package, false);
 575         }
 576
 577 done:
 578         uci_close_stream(file);
 579         if (ctx->err)
 580                 UCI_THROW(ctx, ctx->err);
 581         return package;
 582 }
 583
 584 static UCI_BACKEND(uci_file_backend, "file",
 585         .load = uci_file_load,
 586         .commit = uci_file_commit,
 587         .list_configs = uci_list_config_files,
 588 );