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 /*
  29  * Clean up all extra memory used by the parser and exporter
  30  */
  31 static void uci_file_cleanup(struct uci_context *ctx)
  32 {
  33         struct uci_parse_context *pctx;
  34
  35         if (ctx->buf) {
  36                 free(ctx->buf);
  37                 ctx->buf = NULL;
  38                 ctx->bufsz = 0;
  39         }
  40
  41         pctx = ctx->pctx;
  42         if (!pctx)
  43                 return;
  44
  45         ctx->pctx = NULL;
  46         if (pctx->package)
  47                 uci_free_package(&pctx->package);
  48
  49         if (pctx->buf)
  50                 free(pctx->buf);
  51
  52         free(pctx);
  53 }
  54
  55
  56 /*
  57  * verify that the end of the line or command is reached.
  58  * throw an error if extra arguments are given on the command line
  59  */
  60 static void assert_eol(struct uci_context *ctx, char **str)
  61 {
  62         char *tmp;
  63
  64         tmp = next_arg(ctx, str, false, false);
  65         if (*tmp && (ctx->flags & UCI_FLAG_STRICT))
  66                 uci_parse_error(ctx, *str, "too many arguments");
  67 }
  68
  69 /*
  70  * switch to a different config, either triggered by uci_load, or by a
  71  * 'package <...>' statement in the import file
  72  */
  73 static void uci_switch_config(struct uci_context *ctx)
  74 {
  75         struct uci_parse_context *pctx;
  76         struct uci_element *e;
  77         const char *name;
  78
  79         pctx = ctx->pctx;
  80         name = pctx->name;
  81
  82         /* add the last config to main config file list */
  83         if (pctx->package) {
  84                 uci_list_add(&ctx->root, &pctx->package->e.list);
  85
  86                 pctx->package = NULL;
  87                 pctx->section = NULL;
  88         }
  89
  90         if (!name)
  91                 return;
  92
  93         /*
  94          * if an older config under the same name exists, unload it
  95          * ignore errors here, e.g. if the config was not found
  96          */
  97         e = uci_lookup_list(ctx, &ctx->root, name);
  98         if (e)
  99                 UCI_THROW(ctx, UCI_ERR_DUPLICATE);
 100         pctx->package = uci_alloc_package(ctx, name);
 101 }
 102
 103 /*
 104  * parse the 'package' uci command (next config package)
 105  */
 106 static void uci_parse_package(struct uci_context *ctx, char **str, bool single)
 107 {
 108         char *name = NULL;
 109
 110         /* command string null-terminated by strtok */
 111         *str += strlen(*str) + 1;
 112
 113         name = next_arg(ctx, str, true, true);
 114         assert_eol(ctx, str);
 115         if (single)
 116                 return;
 117
 118         ctx->pctx->name = name;
 119         uci_switch_config(ctx);
 120 }
 121
 122 /* Based on an efficient hash function published by D. J. Bernstein */
 123 static unsigned int djbhash(unsigned int hash, char *str)
 124 {
 125         int len = strlen(str);
 126         int i;
 127
 128         /* initial value */
 129         if (hash == ~0)
 130                 hash = 5381;
 131
 132         for(i = 0; i < len; i++) {
 133                 hash = ((hash << 5) + hash) + str[i];
 134         }
 135         return (hash & 0x7FFFFFFF);
 136 }
 137
 138 /* fix up an unnamed section */
 139 static void uci_fixup_section(struct uci_context *ctx, struct uci_section *s)
 140 {
 141         unsigned int hash = ~0;
 142         struct uci_element *e;
 143         char buf[16];
 144
 145         if (!s || s->e.name)
 146                 return;
 147
 148         /*
 149          * Generate a name for unnamed sections. This is used as reference
 150          * when locating or updating the section from apps/scripts.
 151          * To make multiple concurrent versions somewhat safe for updating,
 152          * the name is generated from a hash of its type and name/value
 153          * pairs of its option, and it is prefixed by a counter value.
 154          * If the order of the unnamed sections changes for some reason,
 155          * updates to them will be rejected.
 156          */
 157         hash = djbhash(hash, s->type);
 158         uci_foreach_element(&s->options, e) {
 159                 hash = djbhash(hash, e->name);
 160                 hash = djbhash(hash, uci_to_option(e)->value);
 161         }
 162         sprintf(buf, "cfg%02x%04x", ++s->package->n_section, hash % (1 << 16));
 163         s->e.name = uci_strdup(ctx, buf);
 164 }
 165
 166 /*
 167  * parse the 'config' uci command (open a section)
 168  */
 169 static void uci_parse_config(struct uci_context *ctx, char **str)
 170 {
 171         struct uci_parse_context *pctx = ctx->pctx;
 172         char *name = NULL;
 173         char *type = NULL;
 174
 175         uci_fixup_section(ctx, ctx->pctx->section);
 176         if (!ctx->pctx->package) {
 177                 if (!ctx->pctx->name)
 178                         uci_parse_error(ctx, *str, "attempting to import a file without a package name");
 179
 180                 uci_switch_config(ctx);
 181         }
 182
 183         /* command string null-terminated by strtok */
 184         *str += strlen(*str) + 1;
 185
 186         type = next_arg(ctx, str, true, false);
 187         if (!uci_validate_str(type, false))
 188                 uci_parse_error(ctx, type, "invalid character in field");
 189         name = next_arg(ctx, str, false, true);
 190         assert_eol(ctx, str);
 191
 192         if (pctx->merge) {
 193                 UCI_TRAP_SAVE(ctx, error);
 194                 uci_set(ctx, pctx->package, name, NULL, type);
 195                 UCI_TRAP_RESTORE(ctx);
 196                 return;
 197 error:
 198                 UCI_THROW(ctx, ctx->errno);
 199         } else
 200                 pctx->section = uci_alloc_section(pctx->package, type, name);
 201 }
 202
 203 /*
 204  * parse the 'option' uci command (open a value)
 205  */
 206 static void uci_parse_option(struct uci_context *ctx, char **str)
 207 {
 208         struct uci_parse_context *pctx = ctx->pctx;
 209         char *name = NULL;
 210         char *value = NULL;
 211
 212         if (!pctx->section)
 213                 uci_parse_error(ctx, *str, "option command found before the first section");
 214
 215         /* command string null-terminated by strtok */
 216         *str += strlen(*str) + 1;
 217
 218         name = next_arg(ctx, str, true, true);
 219         value = next_arg(ctx, str, false, false);
 220         assert_eol(ctx, str);
 221
 222         if (pctx->merge) {
 223                 UCI_TRAP_SAVE(ctx, error);
 224                 uci_set(ctx, pctx->package, pctx->section->e.name, name, value);
 225                 UCI_TRAP_RESTORE(ctx);
 226                 return;
 227 error:
 228                 UCI_THROW(ctx, ctx->errno);
 229         } else
 230                 uci_alloc_option(pctx->section, name, value);
 231 }
 232
 233
 234 /*
 235  * parse a complete input line, split up combined commands by ';'
 236  */
 237 static void uci_parse_line(struct uci_context *ctx, bool single)
 238 {
 239         struct uci_parse_context *pctx = ctx->pctx;
 240         char *word, *brk = NULL;
 241
 242         for (word = strtok_r(pctx->buf, ";", &brk);
 243                  word;
 244                  word = strtok_r(NULL, ";", &brk)) {
 245
 246                 char *pbrk = NULL;
 247                 word = strtok_r(word, " \t", &pbrk);
 248
 249                 if (!word)
 250                         continue;
 251
 252                 switch(word[0]) {
 253                         case '#':
 254                                 return;
 255                         case 'p':
 256                                 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
 257                                         uci_parse_package(ctx, &word, single);
 258                                 break;
 259                         case 'c':
 260                                 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
 261                                         uci_parse_config(ctx, &word);
 262                                 break;
 263                         case 'o':
 264                                 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
 265                                         uci_parse_option(ctx, &word);
 266                                 break;
 267                         default:
 268                                 uci_parse_error(ctx, word, "unterminated command");
 269                                 break;
 270                 }
 271         }
 272 }
 273
 274 /* max number of characters that escaping adds to the string */
 275 #define UCI_QUOTE_ESCAPE        "'\\''"
 276
 277 /*
 278  * escape an uci string for export
 279  */
 280 static char *uci_escape(struct uci_context *ctx, char *str)
 281 {
 282         char *s, *p;
 283         int pos = 0;
 284
 285         if (!ctx->buf) {
 286                 ctx->bufsz = LINEBUF;
 287                 ctx->buf = malloc(LINEBUF);
 288         }
 289
 290         s = str;
 291         p = strchr(str, '\'');
 292         if (!p)
 293                 return str;
 294
 295         do {
 296                 int len = p - s;
 297                 if (len > 0) {
 298                         if (p + sizeof(UCI_QUOTE_ESCAPE) - str >= ctx->bufsz) {
 299                                 ctx->bufsz *= 2;
 300                                 ctx->buf = realloc(ctx->buf, ctx->bufsz);
 301                                 if (!ctx->buf)
 302                                         UCI_THROW(ctx, UCI_ERR_MEM);
 303                         }
 304                         memcpy(&ctx->buf[pos], s, len);
 305                         pos += len;
 306                 }
 307                 strcpy(&ctx->buf[pos], UCI_QUOTE_ESCAPE);
 308                 pos += sizeof(UCI_QUOTE_ESCAPE);
 309                 s = p + 1;
 310         } while ((p = strchr(s, '\'')));
 311
 312         return ctx->buf;
 313 }
 314
 315
 316 /*
 317  * export a single config package to a file stream
 318  */
 319 static void uci_export_package(struct uci_package *p, FILE *stream, bool header)
 320 {
 321         struct uci_context *ctx = p->ctx;
 322         struct uci_element *s, *o;
 323
 324         if (header)
 325                 fprintf(stream, "package '%s'\n", uci_escape(ctx, p->e.name));
 326         uci_foreach_element(&p->sections, s) {
 327                 struct uci_section *sec = uci_to_section(s);
 328                 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, sec->type));
 329                 if (!sec->anonymous || (ctx->flags & UCI_FLAG_EXPORT_NAME))
 330                         fprintf(stream, " '%s'", uci_escape(ctx, sec->e.name));
 331                 fprintf(stream, "\n");
 332                 uci_foreach_element(&sec->options, o) {
 333                         struct uci_option *opt = uci_to_option(o);
 334                         fprintf(stream, "\toption '%s'", uci_escape(ctx, opt->e.name));
 335                         fprintf(stream, " '%s'\n", uci_escape(ctx, opt->value));
 336                 }
 337         }
 338         fprintf(stream, "\n");
 339 }
 340
 341 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package, bool header)
 342 {
 343         struct uci_element *e;
 344
 345         UCI_HANDLE_ERR(ctx);
 346         UCI_ASSERT(ctx, stream != NULL);
 347
 348         if (package)
 349                 uci_export_package(package, stream, header);
 350         else {
 351                 uci_foreach_element(&ctx->root, e) {
 352                         uci_export_package(uci_to_package(e), stream, header);
 353                 }
 354         }
 355
 356         return 0;
 357 }
 358
 359 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package, bool single)
 360 {
 361         struct uci_parse_context *pctx;
 362         UCI_HANDLE_ERR(ctx);
 363
 364         /* make sure no memory from previous parse attempts is leaked */
 365         uci_file_cleanup(ctx);
 366
 367         uci_alloc_parse_context(ctx);
 368         pctx = ctx->pctx;
 369         pctx->file = stream;
 370         if (*package && single) {
 371                 pctx->package = *package;
 372                 pctx->merge = true;
 373         }
 374
 375         /*
 376          * If 'name' was supplied, assume that the supplied stream does not contain
 377          * the appropriate 'package <name>' string to specify the config name
 378          * NB: the config file can still override the package name
 379          */
 380         if (name) {
 381                 UCI_ASSERT(ctx, uci_validate_name(name));
 382                 pctx->name = name;
 383         }
 384
 385         while (!feof(pctx->file)) {
 386                 uci_getln(ctx, 0);
 387                 UCI_TRAP_SAVE(ctx, error);
 388                 if (pctx->buf[0])
 389                         uci_parse_line(ctx, single);
 390                 UCI_TRAP_RESTORE(ctx);
 391                 continue;
 392 error:
 393                 if (ctx->flags & UCI_FLAG_PERROR)
 394                         uci_perror(ctx, NULL);
 395                 if ((ctx->errno != UCI_ERR_PARSE) ||
 396                         (ctx->flags & UCI_FLAG_STRICT))
 397                         UCI_THROW(ctx, ctx->errno);
 398         }
 399
 400         uci_fixup_section(ctx, ctx->pctx->section);
 401         if (package)
 402                 *package = pctx->package;
 403         if (pctx->merge)
 404                 pctx->package = NULL;
 405
 406         pctx->name = NULL;
 407         uci_switch_config(ctx);
 408
 409         /* no error happened, we can get rid of the parser context now */
 410         uci_file_cleanup(ctx);
 411
 412         return 0;
 413 }
 414
 415
 416 static char *uci_config_path(struct uci_context *ctx, const char *name)
 417 {
 418         char *filename;
 419
 420         UCI_ASSERT(ctx, uci_validate_name(name));
 421         filename = uci_malloc(ctx, strlen(name) + strlen(ctx->confdir) + 2);
 422         sprintf(filename, "%s/%s", ctx->confdir, name);
 423
 424         return filename;
 425 }
 426
 427 int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package)
 428 {
 429         char *filename;
 430         bool confdir;
 431         FILE *file = NULL;
 432
 433         UCI_HANDLE_ERR(ctx);
 434
 435         switch (name[0]) {
 436         case '.':
 437                 /* relative path outside of /etc/config */
 438                 if (name[1] != '/')
 439                         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 440                 /* fall through */
 441         case '/':
 442                 /* absolute path outside of /etc/config */
 443                 filename = uci_strdup(ctx, name);
 444                 name = strrchr(name, '/') + 1;
 445                 confdir = false;
 446                 break;
 447         default:
 448                 /* config in /etc/config */
 449                 filename = uci_config_path(ctx, name);
 450                 confdir = true;
 451                 break;
 452         }
 453
 454         file = uci_open_stream(ctx, filename, SEEK_SET, false, false);
 455         ctx->errno = 0;
 456         UCI_TRAP_SAVE(ctx, done);
 457         UCI_INTERNAL(uci_import, ctx, file, name, package, true);
 458         UCI_TRAP_RESTORE(ctx);
 459
 460         if (*package) {
 461                 (*package)->path = filename;
 462                 (*package)->confdir = confdir;
 463                 uci_load_history(ctx, *package, false);
 464         }
 465
 466 done:
 467         uci_close_stream(file);
 468         return ctx->errno;
 469 }
 470
 471 int uci_commit(struct uci_context *ctx, struct uci_package **package, bool overwrite)
 472 {
 473         struct uci_package *p;
 474         FILE *f = NULL;
 475         char *name = NULL;
 476         char *path = NULL;
 477
 478         UCI_HANDLE_ERR(ctx);
 479         UCI_ASSERT(ctx, package != NULL);
 480         p = *package;
 481
 482         UCI_ASSERT(ctx, p != NULL);
 483         if (!p->path) {
 484                 if (overwrite)
 485                         p->path = uci_config_path(ctx, p->e.name);
 486                 else
 487                         UCI_THROW(ctx, UCI_ERR_INVAL);
 488         }
 489
 490
 491         /* open the config file for writing now, so that it is locked */
 492         f = uci_open_stream(ctx, p->path, SEEK_SET, true, true);
 493
 494         /* flush unsaved changes and reload from history file */
 495         UCI_TRAP_SAVE(ctx, done);
 496         if (p->confdir) {
 497                 if (!overwrite) {
 498                         name = uci_strdup(ctx, p->e.name);
 499                         path = uci_strdup(ctx, p->path);
 500                         /* dump our own changes to the history file */
 501                         if (!uci_list_empty(&p->history))
 502                                 UCI_INTERNAL(uci_save, ctx, p);
 503
 504                         /*
 505                          * other processes might have modified the config
 506                          * as well. dump and reload
 507                          */
 508                         uci_free_package(&p);
 509                         uci_file_cleanup(ctx);
 510                         UCI_INTERNAL(uci_import, ctx, f, name, &p, true);
 511
 512                         p->path = path;
 513                         p->confdir = true;
 514                         *package = p;
 515
 516                         /* freed together with the uci_package */
 517                         path = NULL;
 518
 519                         /* check for updated history, flush */
 520                         if (!uci_load_history(ctx, p, true))
 521                                 goto done;
 522                 } else {
 523                         /* flush history */
 524                         if (!uci_load_history(ctx, NULL, true))
 525                                 goto done;
 526                 }
 527         }
 528
 529         rewind(f);
 530         ftruncate(fileno(f), 0);
 531
 532         uci_export(ctx, f, p, false);
 533         UCI_TRAP_RESTORE(ctx);
 534
 535 done:
 536         if (name)
 537                 free(name);
 538         if (path)
 539                 free(path);
 540         uci_close_stream(f);
 541         if (ctx->errno)
 542                 UCI_THROW(ctx, ctx->errno);
 543
 544         return 0;
 545 }
 546
 547
 548 /*
 549  * This function returns the filename by returning the string
 550  * after the last '/' character. By checking for a non-'\0'
 551  * character afterwards, directories are ignored (glob marks
 552  * those with a trailing '/'
 553  */
 554 static inline char *get_filename(char *path)
 555 {
 556         char *p;
 557
 558         p = strrchr(path, '/');
 559         p++;
 560         if (!*p)
 561                 return NULL;
 562         return p;
 563 }
 564
 565 int uci_list_configs(struct uci_context *ctx, char ***list)
 566 {
 567         char **configs;
 568         glob_t globbuf;
 569         int size, i;
 570         char *buf;
 571         char *dir;
 572
 573         UCI_HANDLE_ERR(ctx);
 574
 575         dir = uci_malloc(ctx, strlen(ctx->confdir) + 1 + sizeof("/*"));
 576         sprintf(dir, "%s/*", ctx->confdir);
 577         if (glob(dir, GLOB_MARK, NULL, &globbuf) != 0)
 578                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 579
 580         size = sizeof(char *) * (globbuf.gl_pathc + 1);
 581         for(i = 0; i < globbuf.gl_pathc; i++) {
 582                 char *p;
 583
 584                 p = get_filename(globbuf.gl_pathv[i]);
 585                 if (!p)
 586                         continue;
 587
 588                 size += strlen(p) + 1;
 589         }
 590
 591         configs = uci_malloc(ctx, size);
 592         buf = (char *) &configs[globbuf.gl_pathc + 1];
 593         for(i = 0; i < globbuf.gl_pathc; i++) {
 594                 char *p;
 595
 596                 p = get_filename(globbuf.gl_pathv[i]);
 597                 if (!p)
 598                         continue;
 599
 600                 configs[i] = buf;
 601                 strcpy(buf, p);
 602                 buf += strlen(buf) + 1;
 603         }
 604         *list = configs;
 605         free(dir);
 606
 607         return 0;
 608 }
 609