delta.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 Lesser General Public License for more details.
  13  */
  14
  15 /*
  16  * This file contains the code for handling uci config delta files
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <sys/types.h>
  21 #include <sys/stat.h>
  22 #include <sys/file.h>
  23 #include <stdbool.h>
  24 #include <unistd.h>
  25 #include <fcntl.h>
  26 #include <stdio.h>
  27 #include <ctype.h>
  28 #include <string.h>
  29 #include <stdlib.h>
  30
  31 #include "uci.h"
  32 #include "uci_internal.h"
  33
  34 /* record a change that was done to a package */
  35 void
  36 uci_add_delta(struct uci_context *ctx, struct uci_list *list, int cmd, const char *section, const char *option, const char *value)
  37 {
  38         struct uci_delta *h;
  39         int size = strlen(section) + 1;
  40         char *ptr;
  41
  42         if (value)
  43                 size += strlen(value) + 1;
  44
  45         h = uci_alloc_element(ctx, delta, option, size);
  46         ptr = uci_dataptr(h);
  47         h->cmd = cmd;
  48         h->section = strcpy(ptr, section);
  49         if (value) {
  50                 ptr += strlen(ptr) + 1;
  51                 h->value = strcpy(ptr, value);
  52         }
  53         uci_list_add(list, &h->e.list);
  54 }
  55
  56 void
  57 uci_free_delta(struct uci_delta *h)
  58 {
  59         if (!h)
  60                 return;
  61         if ((h->section != NULL) &&
  62                 (h->section != uci_dataptr(h))) {
  63                 free(h->section);
  64                 free(h->value);
  65         }
  66         uci_free_element(&h->e);
  67 }
  68
  69 static void uci_delta_save(struct uci_context *ctx, FILE *f,
  70                         const char *name, const struct uci_delta *h)
  71 {
  72         const struct uci_element *e = &h->e;
  73         char prefix[2] = {0, 0};
  74
  75         if (h->cmd <= __UCI_CMD_LAST)
  76                 prefix[0] = uci_command_char[h->cmd];
  77
  78         fprintf(f, "%s%s.%s", prefix, name, h->section);
  79         if (e->name)
  80                 fprintf(f, ".%s", e->name);
  81
  82         if (h->cmd == UCI_CMD_REMOVE && !h->value)
  83                 fprintf(f, "\n");
  84         else {
  85                 int i;
  86
  87                 fprintf(f, "='");
  88                 for (i = 0; h->value[i]; i++) {
  89                         unsigned char c = h->value[i];
  90                         if (c != '\'')
  91                                 fputc(c, f);
  92                         else
  93                                 fprintf(f, "'\\''");
  94                 }
  95                 fprintf(f, "'\n");
  96         }
  97 }
  98
  99 int uci_set_savedir(struct uci_context *ctx, const char *dir)
 100 {
 101         char *sdir;
 102         struct uci_element *e, *tmp;
 103         bool exists = false;
 104
 105         UCI_HANDLE_ERR(ctx);
 106         UCI_ASSERT(ctx, dir != NULL);
 107
 108         /* Move dir to the end of ctx->delta_path */
 109         uci_foreach_element_safe(&ctx->delta_path, tmp, e) {
 110                 if (!strcmp(e->name, dir)) {
 111                         exists = true;
 112                         uci_list_del(&e->list);
 113                         break;
 114                 }
 115         }
 116         if (!exists)
 117                 e = uci_alloc_generic(ctx, UCI_TYPE_PATH, dir, sizeof(struct uci_element));
 118         uci_list_add(&ctx->delta_path, &e->list);
 119
 120         sdir = uci_strdup(ctx, dir);
 121         if (ctx->savedir != uci_savedir)
 122                 free(ctx->savedir);
 123         ctx->savedir = sdir;
 124         return 0;
 125 }
 126
 127 int uci_add_delta_path(struct uci_context *ctx, const char *dir)
 128 {
 129         struct uci_element *e;
 130         struct uci_list *savedir;
 131
 132         UCI_HANDLE_ERR(ctx);
 133         UCI_ASSERT(ctx, dir != NULL);
 134
 135         /* Duplicate delta path is not allowed */
 136         uci_foreach_element(&ctx->delta_path, e) {
 137                 if (!strcmp(e->name, dir))
 138                         UCI_THROW(ctx, UCI_ERR_DUPLICATE);
 139         }
 140
 141         e = uci_alloc_generic(ctx, UCI_TYPE_PATH, dir, sizeof(struct uci_element));
 142         /* Keep savedir at the end of ctx->delta_path list */
 143         savedir = ctx->delta_path.prev;
 144         uci_list_insert(savedir->prev, &e->list);
 145
 146         return 0;
 147 }
 148
 149 char const uci_command_char[] = {
 150         [UCI_CMD_ADD] = '+',
 151         [UCI_CMD_REMOVE] = '-',
 152         [UCI_CMD_CHANGE] = 0,
 153         [UCI_CMD_RENAME] = '@',
 154         [UCI_CMD_REORDER] = '^',
 155         [UCI_CMD_LIST_ADD] = '|',
 156         [UCI_CMD_LIST_DEL] = '~'
 157 };
 158
 159 static inline int uci_parse_delta_tuple(struct uci_context *ctx, struct uci_ptr *ptr)
 160 {
 161         struct uci_parse_context *pctx = ctx->pctx;
 162         char *str = pctx_cur_str(pctx), *arg;
 163         int c;
 164
 165         UCI_INTERNAL(uci_parse_argument, ctx, ctx->pctx->file, &str, &arg);
 166         if (str && *str) {
 167                 goto error;
 168         }
 169         for (c = 0; c <= __UCI_CMD_LAST; c++) {
 170                 if (uci_command_char[c] == *arg)
 171                         break;
 172         }
 173         if (c > __UCI_CMD_LAST)
 174                 c = UCI_CMD_CHANGE;
 175
 176         if (c != UCI_CMD_CHANGE)
 177                 arg += 1;
 178
 179         UCI_INTERNAL(uci_parse_ptr, ctx, ptr, arg);
 180
 181         if (!ptr->section)
 182                 goto error;
 183         if (ptr->flags & UCI_LOOKUP_EXTENDED)
 184                 goto error;
 185         if (c != UCI_CMD_REMOVE && !ptr->value) {
 186                 goto error;
 187         }
 188
 189         switch(c) {
 190         case UCI_CMD_REORDER:
 191                 if (!ptr->value || ptr->option)
 192                         goto error;
 193                 break;
 194         case UCI_CMD_RENAME:
 195                 if (!ptr->value || !uci_validate_name(ptr->value))
 196                         goto error;
 197                 break;
 198         case UCI_CMD_LIST_ADD:
 199                 if (!ptr->option)
 200                         goto error;
 201         case UCI_CMD_LIST_DEL:
 202                 if (!ptr->option)
 203                         goto error;
 204         }
 205
 206         return c;
 207
 208 error:
 209         UCI_THROW(ctx, UCI_ERR_INVAL);
 210         return 0;
 211 }
 212
 213 static void uci_parse_delta_line(struct uci_context *ctx, struct uci_package *p)
 214 {
 215         struct uci_element *e = NULL;
 216         struct uci_ptr ptr;
 217         int cmd;
 218
 219         cmd = uci_parse_delta_tuple(ctx, &ptr);
 220         if (strcmp(ptr.package, p->e.name) != 0)
 221                 goto error;
 222
 223         if (ctx->flags & UCI_FLAG_SAVED_DELTA)
 224                 uci_add_delta(ctx, &p->saved_delta, cmd, ptr.section, ptr.option, ptr.value);
 225
 226         switch(cmd) {
 227         case UCI_CMD_REORDER:
 228                 uci_expand_ptr(ctx, &ptr, true);
 229                 if (!ptr.s)
 230                         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 231                 UCI_INTERNAL(uci_reorder_section, ctx, ptr.s, strtoul(ptr.value, NULL, 10));
 232                 break;
 233         case UCI_CMD_RENAME:
 234                 UCI_INTERNAL(uci_rename, ctx, &ptr);
 235                 break;
 236         case UCI_CMD_REMOVE:
 237                 UCI_INTERNAL(uci_delete, ctx, &ptr);
 238                 break;
 239         case UCI_CMD_LIST_ADD:
 240                 UCI_INTERNAL(uci_add_list, ctx, &ptr);
 241                 break;
 242         case UCI_CMD_LIST_DEL:
 243                 UCI_INTERNAL(uci_del_list, ctx, &ptr);
 244                 break;
 245         case UCI_CMD_ADD:
 246         case UCI_CMD_CHANGE:
 247                 UCI_INTERNAL(uci_set, ctx, &ptr);
 248                 e = ptr.last;
 249                 if (!ptr.option && e && (cmd == UCI_CMD_ADD))
 250                         uci_to_section(e)->anonymous = true;
 251                 break;
 252         }
 253         return;
 254 error:
 255         UCI_THROW(ctx, UCI_ERR_PARSE);
 256 }
 257
 258 /* returns the number of changes that were successfully parsed */
 259 static int uci_parse_delta(struct uci_context *ctx, FILE *stream, struct uci_package *p)
 260 {
 261         struct uci_parse_context *pctx;
 262         int changes = 0;
 263
 264         /* make sure no memory from previous parse attempts is leaked */
 265         uci_cleanup(ctx);
 266
 267         pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 268         ctx->pctx = pctx;
 269         pctx->file = stream;
 270
 271         while (!feof(pctx->file)) {
 272                 pctx->pos = 0;
 273                 uci_getln(ctx, 0);
 274                 if (!pctx->buf[0])
 275                         continue;
 276
 277                 /*
 278                  * ignore parse errors in single lines, we want to preserve as much
 279                  * delta as possible
 280                  */
 281                 UCI_TRAP_SAVE(ctx, error);
 282                 uci_parse_delta_line(ctx, p);
 283                 UCI_TRAP_RESTORE(ctx);
 284                 changes++;
 285 error:
 286                 continue;
 287         }
 288
 289         /* no error happened, we can get rid of the parser context now */
 290         uci_cleanup(ctx);
 291         return changes;
 292 }
 293
 294 /* returns the number of changes that were successfully parsed */
 295 static int uci_load_delta_file(struct uci_context *ctx, struct uci_package *p, char *filename, FILE **f, bool flush)
 296 {
 297         FILE *stream = NULL;
 298         int changes = 0;
 299
 300         UCI_TRAP_SAVE(ctx, done);
 301         stream = uci_open_stream(ctx, filename, NULL, SEEK_SET, flush, false);
 302         UCI_TRAP_RESTORE(ctx);
 303
 304         if (p)
 305                 changes = uci_parse_delta(ctx, stream, p);
 306
 307 done:
 308         if (f)
 309                 *f = stream;
 310         else
 311                 uci_close_stream(stream);
 312         return changes;
 313 }
 314
 315 /* returns the number of changes that were successfully parsed */
 316 __private int uci_load_delta(struct uci_context *ctx, struct uci_package *p, bool flush)
 317 {
 318         struct uci_element *e;
 319         char *filename = NULL;
 320         FILE *f = NULL;
 321         int changes = 0;
 322
 323         if (!p->has_delta)
 324                 return 0;
 325
 326         uci_foreach_element(&ctx->delta_path, e) {
 327                 if ((asprintf(&filename, "%s/%s", e->name, p->e.name) < 0) || !filename)
 328                         UCI_THROW(ctx, UCI_ERR_MEM);
 329
 330                 changes += uci_load_delta_file(ctx, p, filename, NULL, false);
 331                 free(filename);
 332         }
 333
 334         if ((asprintf(&filename, "%s/%s", ctx->savedir, p->e.name) < 0) || !filename)
 335                 UCI_THROW(ctx, UCI_ERR_MEM);
 336         UCI_TRAP_SAVE(ctx, done);
 337         f = uci_open_stream(ctx, filename, NULL, SEEK_SET, flush, false);
 338         UCI_TRAP_RESTORE(ctx);
 339
 340         if (flush && f && (changes > 0)) {
 341                 if (ftruncate(fileno(f), 0) < 0) {
 342                         free(filename);
 343                         uci_close_stream(f);
 344                         UCI_THROW(ctx, UCI_ERR_IO);
 345                 }
 346         }
 347
 348 done:
 349         free(filename);
 350         uci_close_stream(f);
 351         ctx->err = 0;
 352         return changes;
 353 }
 354
 355 static void uci_filter_delta(struct uci_context *ctx, const char *name, const char *section, const char *option)
 356 {
 357         struct uci_parse_context *pctx;
 358         struct uci_element *e, *tmp;
 359         struct uci_list list;
 360         char *filename = NULL;
 361         struct uci_ptr ptr;
 362         FILE *f = NULL;
 363
 364         uci_list_init(&list);
 365         uci_alloc_parse_context(ctx);
 366         pctx = ctx->pctx;
 367
 368         if ((asprintf(&filename, "%s/%s", ctx->savedir, name) < 0) || !filename)
 369                 UCI_THROW(ctx, UCI_ERR_MEM);
 370
 371         UCI_TRAP_SAVE(ctx, done);
 372         f = uci_open_stream(ctx, filename, NULL, SEEK_SET, true, false);
 373         pctx->file = f;
 374         while (!feof(f)) {
 375                 enum uci_command c;
 376                 bool match;
 377
 378                 pctx->pos = 0;
 379                 uci_getln(ctx, 0);
 380                 if (!pctx->buf[0])
 381                         continue;
 382
 383                 c = uci_parse_delta_tuple(ctx, &ptr);
 384                 match = true;
 385                 if (section) {
 386                         if (!ptr.section || (strcmp(section, ptr.section) != 0))
 387                                 match = false;
 388                 }
 389                 if (match && option) {
 390                         if (!ptr.option || (strcmp(option, ptr.option) != 0))
 391                                 match = false;
 392                 }
 393
 394                 if (!match) {
 395                         uci_add_delta(ctx, &list, c,
 396                                 ptr.section, ptr.option, ptr.value);
 397                 }
 398         }
 399
 400         /* rebuild the delta file */
 401         rewind(f);
 402         if (ftruncate(fileno(f), 0) < 0)
 403                 UCI_THROW(ctx, UCI_ERR_IO);
 404         uci_foreach_element_safe(&list, tmp, e) {
 405                 struct uci_delta *h = uci_to_delta(e);
 406                 uci_delta_save(ctx, f, name, h);
 407                 uci_free_delta(h);
 408         }
 409         UCI_TRAP_RESTORE(ctx);
 410
 411 done:
 412         free(filename);
 413         uci_close_stream(pctx->file);
 414         uci_foreach_element_safe(&list, tmp, e) {
 415                 uci_free_delta(uci_to_delta(e));
 416         }
 417         uci_cleanup(ctx);
 418 }
 419
 420 int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr)
 421 {
 422         char *package = NULL;
 423         char *section = NULL;
 424         char *option = NULL;
 425
 426         UCI_HANDLE_ERR(ctx);
 427         uci_expand_ptr(ctx, ptr, false);
 428         UCI_ASSERT(ctx, ptr->p->has_delta);
 429
 430         /*
 431          * - flush unwritten changes
 432          * - save the package name
 433          * - unload the package
 434          * - filter the delta
 435          * - reload the package
 436          */
 437         UCI_TRAP_SAVE(ctx, error);
 438         UCI_INTERNAL(uci_save, ctx, ptr->p);
 439
 440         /* NB: need to clone package, section and option names,
 441          * as they may get freed on uci_free_package() */
 442         package = uci_strdup(ctx, ptr->p->e.name);
 443         if (ptr->section)
 444                 section = uci_strdup(ctx, ptr->section);
 445         if (ptr->option)
 446                 option = uci_strdup(ctx, ptr->option);
 447
 448         uci_free_package(&ptr->p);
 449         uci_filter_delta(ctx, package, section, option);
 450
 451         UCI_INTERNAL(uci_load, ctx, package, &ptr->p);
 452         UCI_TRAP_RESTORE(ctx);
 453         ctx->err = 0;
 454
 455 error:
 456         free(package);
 457         free(section);
 458         free(option);
 459         if (ctx->err)
 460                 UCI_THROW(ctx, ctx->err);
 461         return 0;
 462 }
 463
 464 int uci_save(struct uci_context *ctx, struct uci_package *p)
 465 {
 466         FILE *f = NULL;
 467         char *filename = NULL;
 468         struct uci_element *e, *tmp;
 469         struct stat statbuf;
 470
 471         UCI_HANDLE_ERR(ctx);
 472         UCI_ASSERT(ctx, p != NULL);
 473
 474         /*
 475          * if the config file was outside of the /etc/config path,
 476          * don't save the delta to a file, update the real file
 477          * directly.
 478          * does not modify the uci_package pointer
 479          */
 480         if (!p->has_delta)
 481                 return uci_commit(ctx, &p, false);
 482
 483         if (uci_list_empty(&p->delta))
 484                 return 0;
 485
 486         if (stat(ctx->savedir, &statbuf) < 0) {
 487                 if (stat(ctx->confdir, &statbuf) == 0) {
 488                         mkdir(ctx->savedir, statbuf.st_mode);
 489                 } else {
 490                         mkdir(ctx->savedir, UCI_DIRMODE);
 491                 }
 492         } else if ((statbuf.st_mode & S_IFMT) != S_IFDIR) {
 493                 UCI_THROW(ctx, UCI_ERR_IO);
 494         }
 495
 496         if ((asprintf(&filename, "%s/%s", ctx->savedir, p->e.name) < 0) || !filename)
 497                 UCI_THROW(ctx, UCI_ERR_MEM);
 498
 499         ctx->err = 0;
 500         UCI_TRAP_SAVE(ctx, done);
 501         f = uci_open_stream(ctx, filename, NULL, SEEK_END, true, true);
 502         UCI_TRAP_RESTORE(ctx);
 503
 504         uci_foreach_element_safe(&p->delta, tmp, e) {
 505                 struct uci_delta *h = uci_to_delta(e);
 506                 uci_delta_save(ctx, f, p->e.name, h);
 507                 uci_free_delta(h);
 508         }
 509
 510 done:
 511         uci_close_stream(f);
 512         free(filename);
 513         if (ctx->err)
 514                 UCI_THROW(ctx, ctx->err);
 515
 516         return 0;
 517 }
 518
 519