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