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