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