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_TRAP_SAVE(ctx, error);
 127                 if (uci_set(ctx, pctx->package, name, NULL, type, NULL) != UCI_OK)
 128                         goto error;
 129                 UCI_TRAP_RESTORE(ctx);
 130                 return;
 131 error:
 132                 UCI_THROW(ctx, ctx->err);
 133         } else
 134                 pctx->section = uci_alloc_section(pctx->package, type, name);
 135 }
 136
 137 /*
 138  * parse the 'option' uci command (open a value)
 139  */
 140 static void uci_parse_option(struct uci_context *ctx, char **str)
 141 {
 142         struct uci_parse_context *pctx = ctx->pctx;
 143         char *name = NULL;
 144         char *value = NULL;
 145
 146         if (!pctx->section)
 147                 uci_parse_error(ctx, *str, "option command found before the first section");
 148
 149         /* command string null-terminated by strtok */
 150         *str += strlen(*str) + 1;
 151
 152         name = next_arg(ctx, str, true, true);
 153         value = next_arg(ctx, str, false, false);
 154         assert_eol(ctx, str);
 155
 156         if (pctx->merge) {
 157                 UCI_TRAP_SAVE(ctx, error);
 158                 uci_set(ctx, pctx->package, pctx->section->e.name, name, value, NULL);
 159                 UCI_TRAP_RESTORE(ctx);
 160                 return;
 161 error:
 162                 UCI_THROW(ctx, ctx->err);
 163         } else
 164                 uci_alloc_option(pctx->section, name, value);
 165 }
 166
 167 static void uci_parse_list(struct uci_context *ctx, char **str)
 168 {
 169         struct uci_parse_context *pctx = ctx->pctx;
 170         char *name = NULL;
 171         char *value = NULL;
 172
 173         if (!pctx->section)
 174                 uci_parse_error(ctx, *str, "list command found before the first section");
 175
 176         /* command string null-terminated by strtok */
 177         *str += strlen(*str) + 1;
 178
 179         name = next_arg(ctx, str, true, true);
 180         value = next_arg(ctx, str, false, false);
 181         assert_eol(ctx, str);
 182
 183         if (pctx->merge) {
 184                 UCI_TRAP_SAVE(ctx, error);
 185                 uci_add_list(ctx, pctx->package, pctx->section->e.name, name, value, NULL);
 186                 UCI_TRAP_RESTORE(ctx);
 187                 return;
 188 error:
 189                 UCI_THROW(ctx, ctx->err);
 190         } else {
 191                 struct uci_option *o;
 192                 struct uci_element *e;
 193
 194                 e = uci_lookup_list(&pctx->section->options, name);
 195                 o = uci_to_option(e);
 196                 if (!o) {
 197                         o = uci_alloc_list(pctx->section, name);
 198                 } else {
 199                         if (o->type != UCI_TYPE_LIST)
 200                                 uci_parse_error(ctx, *str, "conflicting list/option keywords");
 201                 }
 202                 UCI_INTERNAL(uci_add_element_list, ctx, o, value);
 203         }
 204 }
 205
 206
 207 /*
 208  * parse a complete input line, split up combined commands by ';'
 209  */
 210 static void uci_parse_line(struct uci_context *ctx, bool single)
 211 {
 212         struct uci_parse_context *pctx = ctx->pctx;
 213         char *word, *brk;
 214
 215         word = pctx->buf;
 216         do {
 217                 brk = NULL;
 218                 word = strtok_r(word, " \t", &brk);
 219                 if (!word)
 220                         return;
 221
 222                 switch(word[0]) {
 223                         case 0:
 224                         case '#':
 225                                 return;
 226                         case 'p':
 227                                 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
 228                                         uci_parse_package(ctx, &word, single);
 229                                 else
 230                                         goto invalid;
 231                                 break;
 232                         case 'c':
 233                                 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
 234                                         uci_parse_config(ctx, &word);
 235                                 else
 236                                         goto invalid;
 237                                 break;
 238                         case 'o':
 239                                 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
 240                                         uci_parse_option(ctx, &word);
 241                                 else
 242                                         goto invalid;
 243                                 break;
 244                         case 'l':
 245                                 if ((word[1] == 0) || !strcmp(word + 1, "ist"))
 246                                         uci_parse_list(ctx, &word);
 247                                 else
 248                                         goto invalid;
 249                                 break;
 250                         default:
 251                                 goto invalid;
 252                 }
 253                 continue;
 254 invalid:
 255                 uci_parse_error(ctx, word, "invalid command");
 256         } while (1);
 257 }
 258
 259 /* max number of characters that escaping adds to the string */
 260 #define UCI_QUOTE_ESCAPE        "'\\''"
 261
 262 /*
 263  * escape an uci string for export
 264  */
 265 static char *uci_escape(struct uci_context *ctx, const char *str)
 266 {
 267         const char *end;
 268         int ofs = 0;
 269
 270         if (!ctx->buf) {
 271                 ctx->bufsz = LINEBUF;
 272                 ctx->buf = malloc(LINEBUF);
 273         }
 274
 275         while (1) {
 276                 int len;
 277
 278                 end = strchr(str, '\'');
 279                 if (!end)
 280                         end = str + strlen(str);
 281                 len = end - str;
 282
 283                 /* make sure that we have enough room in the buffer */
 284                 while (ofs + len + sizeof(UCI_QUOTE_ESCAPE) + 1 > ctx->bufsz) {
 285                         ctx->bufsz *= 2;
 286                         ctx->buf = uci_realloc(ctx, ctx->buf, ctx->bufsz);
 287                 }
 288
 289                 /* copy the string until the character before the quote */
 290                 memcpy(&ctx->buf[ofs], str, len);
 291                 ofs += len;
 292
 293                 /* end of string? return the buffer */
 294                 if (*end == 0)
 295                         break;
 296
 297                 memcpy(&ctx->buf[ofs], UCI_QUOTE_ESCAPE, sizeof(UCI_QUOTE_ESCAPE));
 298                 ofs += strlen(&ctx->buf[ofs]);
 299                 str = end + 1;
 300         }
 301
 302         ctx->buf[ofs] = 0;
 303         return ctx->buf;
 304 }
 305
 306 /*
 307  * export a single config package to a file stream
 308  */
 309 static void uci_export_package(struct uci_package *p, FILE *stream, bool header)
 310 {
 311         struct uci_context *ctx = p->ctx;
 312         struct uci_element *s, *o, *i;
 313
 314         if (header)
 315                 fprintf(stream, "package '%s'\n", uci_escape(ctx, p->e.name));
 316         uci_foreach_element(&p->sections, s) {
 317                 struct uci_section *sec = uci_to_section(s);
 318                 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, sec->type));
 319                 if (!sec->anonymous || (ctx->flags & UCI_FLAG_EXPORT_NAME))
 320                         fprintf(stream, " '%s'", uci_escape(ctx, sec->e.name));
 321                 fprintf(stream, "\n");
 322                 uci_foreach_element(&sec->options, o) {
 323                         struct uci_option *opt = uci_to_option(o);
 324                         switch(opt->type) {
 325                         case UCI_TYPE_STRING:
 326                                 fprintf(stream, "\toption '%s'", uci_escape(ctx, opt->e.name));
 327                                 fprintf(stream, " '%s'\n", uci_escape(ctx, opt->v.string));
 328                                 break;
 329                         case UCI_TYPE_LIST:
 330                                 uci_foreach_element(&opt->v.list, i) {
 331                                         fprintf(stream, "\tlist '%s'", uci_escape(ctx, opt->e.name));
 332                                         fprintf(stream, " '%s'\n", uci_escape(ctx, i->name));
 333                                 }
 334                                 break;
 335                         default:
 336                                 fprintf(stream, "\t# unknown type for option '%s'\n", uci_escape(ctx, opt->e.name));
 337                                 break;
 338                         }
 339                 }
 340         }
 341         fprintf(stream, "\n");
 342 }
 343
 344 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header)
 345 {
 346         struct uci_element *e;
 347
 348         UCI_HANDLE_ERR(ctx);
 349         UCI_ASSERT(ctx, stream != NULL);
 350
 351         if (package)
 352                 uci_export_package(package, stream, header);
 353         else {
 354                 uci_foreach_element(&ctx->root, e) {
 355                         uci_export_package(uci_to_package(e), stream, header);
 356                 }
 357         }
 358
 359         return 0;
 360 }
 361
 362 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single)
 363 {
 364         struct uci_parse_context *pctx;
 365         UCI_HANDLE_ERR(ctx);
 366
 367         /* make sure no memory from previous parse attempts is leaked */
 368         uci_cleanup(ctx);
 369
 370         uci_alloc_parse_context(ctx);
 371         pctx = ctx->pctx;
 372         pctx->file = stream;
 373         if (*package && single) {
 374                 pctx->package = *package;
 375                 pctx->merge = true;
 376         }
 377
 378         /*
 379          * If 'name' was supplied, assume that the supplied stream does not contain
 380          * the appropriate 'package <name>' string to specify the config name
 381          * NB: the config file can still override the package name
 382          */
 383         if (name) {
 384                 UCI_ASSERT(ctx, uci_validate_str(name, false));
 385                 pctx->name = name;
 386         }
 387
 388         while (!feof(pctx->file)) {
 389                 uci_getln(ctx, 0);
 390                 UCI_TRAP_SAVE(ctx, error);
 391                 if (pctx->buf[0])
 392                         uci_parse_line(ctx, single);
 393                 UCI_TRAP_RESTORE(ctx);
 394                 continue;
 395 error:
 396                 if (ctx->flags & UCI_FLAG_PERROR)
 397                         uci_perror(ctx, NULL);
 398                 if ((ctx->err != UCI_ERR_PARSE) ||
 399                         (ctx->flags & UCI_FLAG_STRICT))
 400                         UCI_THROW(ctx, ctx->err);
 401         }
 402
 403         uci_fixup_section(ctx, ctx->pctx->section);
 404         if (!pctx->package && name)
 405                 uci_switch_config(ctx);
 406         if (package)
 407                 *package = pctx->package;
 408         if (pctx->merge)
 409                 pctx->package = NULL;
 410
 411         pctx->name = NULL;
 412         uci_switch_config(ctx);
 413
 414         /* no error happened, we can get rid of the parser context now */
 415         uci_cleanup(ctx);
 416
 417         return 0;
 418 }
 419
 420
 421 static char *uci_config_path(struct uci_context *ctx, const char *name)
 422 {
 423         char *filename;
 424
 425         UCI_ASSERT(ctx, uci_validate_str(name, false));
 426         filename = uci_malloc(ctx, strlen(name) + strlen(ctx->confdir) + 2);
 427         sprintf(filename, "%s/%s", ctx->confdir, name);
 428
 429         return filename;
 430 }
 431
 432 void uci_file_commit(struct uci_context *ctx, struct uci_package **package, bool overwrite)
 433 {
 434         struct uci_package *p = *package;
 435         FILE *f = NULL;
 436         char *name = NULL;
 437         char *path = NULL;
 438
 439         if (!p->path) {
 440                 if (overwrite)
 441                         p->path = uci_config_path(ctx, p->e.name);
 442                 else
 443                         UCI_THROW(ctx, UCI_ERR_INVAL);
 444         }
 445
 446         /* open the config file for writing now, so that it is locked */
 447         f = uci_open_stream(ctx, p->path, SEEK_SET, true, true);
 448
 449         /* flush unsaved changes and reload from history file */
 450         UCI_TRAP_SAVE(ctx, done);
 451         if (p->has_history) {
 452                 if (!overwrite) {
 453                         name = uci_strdup(ctx, p->e.name);
 454                         path = uci_strdup(ctx, p->path);
 455                         /* dump our own changes to the history file */
 456                         if (!uci_list_empty(&p->history))
 457                                 UCI_INTERNAL(uci_save, ctx, p);
 458
 459                         /*
 460                          * other processes might have modified the config
 461                          * as well. dump and reload
 462                          */
 463                         uci_free_package(&p);
 464                         uci_cleanup(ctx);
 465                         UCI_INTERNAL(uci_import, ctx, f, name, &p, true);
 466
 467                         p->path = path;
 468                         p->has_history = true;
 469                         *package = p;
 470
 471                         /* freed together with the uci_package */
 472                         path = NULL;
 473
 474                         /* check for updated history, flush */
 475                         if (!uci_load_history(ctx, p, true))
 476                                 goto done;
 477                 } else {
 478                         /* flush history */
 479                         if (!uci_load_history(ctx, NULL, true))
 480                                 goto done;
 481                 }
 482         }
 483
 484         rewind(f);
 485         ftruncate(fileno(f), 0);
 486
 487         uci_export(ctx, f, p, false);
 488         UCI_TRAP_RESTORE(ctx);
 489
 490 done:
 491         if (name)
 492                 free(name);
 493         if (path)
 494                 free(path);
 495         uci_close_stream(f);
 496         if (ctx->err)
 497                 UCI_THROW(ctx, ctx->err);
 498 }
 499
 500
 501 /*
 502  * This function returns the filename by returning the string
 503  * after the last '/' character. By checking for a non-'\0'
 504  * character afterwards, directories are ignored (glob marks
 505  * those with a trailing '/'
 506  */
 507 static inline char *get_filename(char *path)
 508 {
 509         char *p;
 510
 511         p = strrchr(path, '/');
 512         p++;
 513         if (!*p)
 514                 return NULL;
 515         return p;
 516 }
 517
 518 static char **uci_list_config_files(struct uci_context *ctx)
 519 {
 520         char **configs;
 521         glob_t globbuf;
 522         int size, i;
 523         char *buf;
 524         char *dir;
 525
 526         dir = uci_malloc(ctx, strlen(ctx->confdir) + 1 + sizeof("/*"));
 527         sprintf(dir, "%s/*", ctx->confdir);
 528         if (glob(dir, GLOB_MARK, NULL, &globbuf) != 0)
 529                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 530
 531         size = sizeof(char *) * (globbuf.gl_pathc + 1);
 532         for(i = 0; i < globbuf.gl_pathc; i++) {
 533                 char *p;
 534
 535                 p = get_filename(globbuf.gl_pathv[i]);
 536                 if (!p)
 537                         continue;
 538
 539                 size += strlen(p) + 1;
 540         }
 541
 542         configs = uci_malloc(ctx, size);
 543         buf = (char *) &configs[globbuf.gl_pathc + 1];
 544         for(i = 0; i < globbuf.gl_pathc; i++) {
 545                 char *p;
 546
 547                 p = get_filename(globbuf.gl_pathv[i]);
 548                 if (!p)
 549                         continue;
 550
 551                 if (!uci_validate_name(p))
 552                         continue;
 553
 554                 configs[i] = buf;
 555                 strcpy(buf, p);
 556                 buf += strlen(buf) + 1;
 557         }
 558         free(dir);
 559         return configs;
 560 }
 561
 562 static struct uci_package *uci_file_load(struct uci_context *ctx, const char *name)
 563 {
 564         struct uci_package *package = NULL;
 565         char *filename;
 566         bool confdir;
 567         FILE *file = NULL;
 568
 569         switch (name[0]) {
 570         case '.':
 571                 /* relative path outside of /etc/config */
 572                 if (name[1] != '/')
 573                         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 574                 /* fall through */
 575         case '/':
 576                 /* absolute path outside of /etc/config */
 577                 filename = uci_strdup(ctx, name);
 578                 name = strrchr(name, '/') + 1;
 579                 confdir = false;
 580                 break;
 581         default:
 582                 /* config in /etc/config */
 583                 filename = uci_config_path(ctx, name);
 584                 confdir = true;
 585                 break;
 586         }
 587
 588         file = uci_open_stream(ctx, filename, SEEK_SET, false, false);
 589         ctx->err = 0;
 590         UCI_TRAP_SAVE(ctx, done);
 591         UCI_INTERNAL(uci_import, ctx, file, name, &package, true);
 592         UCI_TRAP_RESTORE(ctx);
 593
 594         if (package) {
 595                 package->path = filename;
 596                 package->has_history = confdir;
 597                 uci_load_history(ctx, package, false);
 598         }
 599
 600 done:
 601         uci_close_stream(file);
 602         if (ctx->err)
 603                 UCI_THROW(ctx, ctx->err);
 604         return package;
 605 }
 606
 607 static UCI_BACKEND(uci_file_backend, "file",
 608         .load = uci_file_load,
 609         .commit = uci_file_commit,
 610         .list_configs = uci_list_config_files,
 611 );