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