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         for (c = 0; c <= __UCI_CMD_LAST; c++) {
 167                 if (uci_command_char[c] == *arg)
 168                         break;
 169         }
 170         if (c > __UCI_CMD_LAST)
 171                 c = UCI_CMD_CHANGE;
 172
 173         if (c != UCI_CMD_CHANGE)
 174                 arg += 1;
 175
 176         UCI_INTERNAL(uci_parse_ptr, ctx, ptr, arg);
 177
 178         if (!ptr->section)
 179                 goto error;
 180         if (ptr->flags & UCI_LOOKUP_EXTENDED)
 181                 goto error;
 182
 183         switch(c) {
 184         case UCI_CMD_REORDER:
 185                 if (!ptr->value || ptr->option)
 186                         goto error;
 187                 break;
 188         case UCI_CMD_RENAME:
 189                 if (!ptr->value || !uci_validate_name(ptr->value))
 190                         goto error;
 191                 break;
 192         case UCI_CMD_LIST_ADD:
 193                 if (!ptr->option)
 194                         goto error;
 195         case UCI_CMD_LIST_DEL:
 196                 if (!ptr->option)
 197                         goto error;
 198         }
 199
 200         return c;
 201
 202 error:
 203         UCI_THROW(ctx, UCI_ERR_INVAL);
 204         return 0;
 205 }
 206
 207 static void uci_parse_delta_line(struct uci_context *ctx, struct uci_package *p)
 208 {
 209         struct uci_element *e = NULL;
 210         struct uci_ptr ptr;
 211         int cmd;
 212
 213         cmd = uci_parse_delta_tuple(ctx, &ptr);
 214         if (strcmp(ptr.package, p->e.name) != 0)
 215                 goto error;
 216
 217         if (ctx->flags & UCI_FLAG_SAVED_DELTA)
 218                 uci_add_delta(ctx, &p->saved_delta, cmd, ptr.section, ptr.option, ptr.value);
 219
 220         switch(cmd) {
 221         case UCI_CMD_REORDER:
 222                 uci_expand_ptr(ctx, &ptr, true);
 223                 if (!ptr.s)
 224                         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 225                 UCI_INTERNAL(uci_reorder_section, ctx, ptr.s, strtoul(ptr.value, NULL, 10));
 226                 break;
 227         case UCI_CMD_RENAME:
 228                 UCI_INTERNAL(uci_rename, ctx, &ptr);
 229                 break;
 230         case UCI_CMD_REMOVE:
 231                 UCI_INTERNAL(uci_delete, ctx, &ptr);
 232                 break;
 233         case UCI_CMD_LIST_ADD:
 234                 UCI_INTERNAL(uci_add_list, ctx, &ptr);
 235                 break;
 236         case UCI_CMD_LIST_DEL:
 237                 UCI_INTERNAL(uci_del_list, ctx, &ptr);
 238                 break;
 239         case UCI_CMD_ADD:
 240         case UCI_CMD_CHANGE:
 241                 UCI_INTERNAL(uci_set, ctx, &ptr);
 242                 e = ptr.last;
 243                 if (!ptr.option && e && (cmd == UCI_CMD_ADD))
 244                         uci_to_section(e)->anonymous = true;
 245                 break;
 246         }
 247         return;
 248 error:
 249         UCI_THROW(ctx, UCI_ERR_PARSE);
 250 }
 251
 252 /* returns the number of changes that were successfully parsed */
 253 static int uci_parse_delta(struct uci_context *ctx, FILE *stream, struct uci_package *p)
 254 {
 255         struct uci_parse_context *pctx;
 256         int changes = 0;
 257
 258         /* make sure no memory from previous parse attempts is leaked */
 259         uci_cleanup(ctx);
 260
 261         pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 262         ctx->pctx = pctx;
 263         pctx->file = stream;
 264
 265         while (!feof(pctx->file)) {
 266                 pctx->pos = 0;
 267                 uci_getln(ctx, 0);
 268                 if (!pctx->buf[0])
 269                         continue;
 270
 271                 /*
 272                  * ignore parse errors in single lines, we want to preserve as much
 273                  * delta as possible
 274                  */
 275                 UCI_TRAP_SAVE(ctx, error);
 276                 uci_parse_delta_line(ctx, p);
 277                 UCI_TRAP_RESTORE(ctx);
 278                 changes++;
 279 error:
 280                 continue;
 281         }
 282
 283         /* no error happened, we can get rid of the parser context now */
 284         uci_cleanup(ctx);
 285         return changes;
 286 }
 287
 288 /* returns the number of changes that were successfully parsed */
 289 static int uci_load_delta_file(struct uci_context *ctx, struct uci_package *p, char *filename, FILE **f, bool flush)
 290 {
 291         FILE *stream = NULL;
 292         int changes = 0;
 293
 294         UCI_TRAP_SAVE(ctx, done);
 295         stream = uci_open_stream(ctx, filename, NULL, SEEK_SET, flush, false);
 296         UCI_TRAP_RESTORE(ctx);
 297
 298         if (p)
 299                 changes = uci_parse_delta(ctx, stream, p);
 300
 301 done:
 302         if (f)
 303                 *f = stream;
 304         else
 305                 uci_close_stream(stream);
 306         return changes;
 307 }
 308
 309 /* returns the number of changes that were successfully parsed */
 310 __private int uci_load_delta(struct uci_context *ctx, struct uci_package *p, bool flush)
 311 {
 312         struct uci_element *e;
 313         char *filename = NULL;
 314         FILE *f = NULL;
 315         int changes = 0;
 316
 317         if (!p->has_delta)
 318                 return 0;
 319
 320         uci_foreach_element(&ctx->delta_path, e) {
 321                 if ((asprintf(&filename, "%s/%s", e->name, p->e.name) < 0) || !filename)
 322                         UCI_THROW(ctx, UCI_ERR_MEM);
 323
 324                 changes += uci_load_delta_file(ctx, p, filename, NULL, false);
 325                 free(filename);
 326         }
 327
 328         if ((asprintf(&filename, "%s/%s", ctx->savedir, p->e.name) < 0) || !filename)
 329                 UCI_THROW(ctx, UCI_ERR_MEM);
 330         UCI_TRAP_SAVE(ctx, done);
 331         f = uci_open_stream(ctx, filename, NULL, SEEK_SET, flush, false);
 332         UCI_TRAP_RESTORE(ctx);
 333
 334         if (flush && f && (changes > 0)) {
 335                 if (ftruncate(fileno(f), 0) < 0) {
 336                         free(filename);
 337                         uci_close_stream(f);
 338                         UCI_THROW(ctx, UCI_ERR_IO);
 339                 }
 340         }
 341
 342 done:
 343         free(filename);
 344         uci_close_stream(f);
 345         ctx->err = 0;
 346         return changes;
 347 }
 348
 349 static void uci_filter_delta(struct uci_context *ctx, const char *name, const char *section, const char *option)
 350 {
 351         struct uci_parse_context *pctx;
 352         struct uci_element *e, *tmp;
 353         struct uci_list list;
 354         char *filename = NULL;
 355         struct uci_ptr ptr;
 356         FILE *f = NULL;
 357
 358         uci_list_init(&list);
 359         uci_alloc_parse_context(ctx);
 360         pctx = ctx->pctx;
 361
 362         if ((asprintf(&filename, "%s/%s", ctx->savedir, name) < 0) || !filename)
 363                 UCI_THROW(ctx, UCI_ERR_MEM);
 364
 365         UCI_TRAP_SAVE(ctx, done);
 366         f = uci_open_stream(ctx, filename, NULL, SEEK_SET, true, false);
 367         pctx->file = f;
 368         while (!feof(f)) {
 369                 enum uci_command c;
 370                 bool match;
 371
 372                 pctx->pos = 0;
 373                 uci_getln(ctx, 0);
 374                 if (!pctx->buf[0])
 375                         continue;
 376
 377                 c = uci_parse_delta_tuple(ctx, &ptr);
 378                 match = true;
 379                 if (section) {
 380                         if (!ptr.section || (strcmp(section, ptr.section) != 0))
 381                                 match = false;
 382                 }
 383                 if (match && option) {
 384                         if (!ptr.option || (strcmp(option, ptr.option) != 0))
 385                                 match = false;
 386                 }
 387
 388                 if (!match) {
 389                         uci_add_delta(ctx, &list, c,
 390                                 ptr.section, ptr.option, ptr.value);
 391                 }
 392         }
 393
 394         /* rebuild the delta file */
 395         rewind(f);
 396         if (ftruncate(fileno(f), 0) < 0)
 397                 UCI_THROW(ctx, UCI_ERR_IO);
 398         uci_foreach_element_safe(&list, tmp, e) {
 399                 struct uci_delta *h = uci_to_delta(e);
 400                 uci_delta_save(ctx, f, name, h);
 401                 uci_free_delta(h);
 402         }
 403         UCI_TRAP_RESTORE(ctx);
 404
 405 done:
 406         free(filename);
 407         uci_close_stream(pctx->file);
 408         uci_foreach_element_safe(&list, tmp, e) {
 409                 uci_free_delta(uci_to_delta(e));
 410         }
 411         uci_cleanup(ctx);
 412 }
 413
 414 int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr)
 415 {
 416         char *package = NULL;
 417         char *section = NULL;
 418         char *option = NULL;
 419
 420         UCI_HANDLE_ERR(ctx);
 421         uci_expand_ptr(ctx, ptr, false);
 422         UCI_ASSERT(ctx, ptr->p->has_delta);
 423
 424         /*
 425          * - flush unwritten changes
 426          * - save the package name
 427          * - unload the package
 428          * - filter the delta
 429          * - reload the package
 430          */
 431         UCI_TRAP_SAVE(ctx, error);
 432         UCI_INTERNAL(uci_save, ctx, ptr->p);
 433
 434         /* NB: need to clone package, section and option names,
 435          * as they may get freed on uci_free_package() */
 436         package = uci_strdup(ctx, ptr->p->e.name);
 437         if (ptr->section)
 438                 section = uci_strdup(ctx, ptr->section);
 439         if (ptr->option)
 440                 option = uci_strdup(ctx, ptr->option);
 441
 442         uci_free_package(&ptr->p);
 443         uci_filter_delta(ctx, package, section, option);
 444
 445         UCI_INTERNAL(uci_load, ctx, package, &ptr->p);
 446         UCI_TRAP_RESTORE(ctx);
 447         ctx->err = 0;
 448
 449 error:
 450         free(package);
 451         free(section);
 452         free(option);
 453         if (ctx->err)
 454                 UCI_THROW(ctx, ctx->err);
 455         return 0;
 456 }
 457
 458 int uci_save(struct uci_context *ctx, struct uci_package *p)
 459 {
 460         FILE *f = NULL;
 461         char *filename = NULL;
 462         struct uci_element *e, *tmp;
 463         struct stat statbuf;
 464
 465         UCI_HANDLE_ERR(ctx);
 466         UCI_ASSERT(ctx, p != NULL);
 467
 468         /*
 469          * if the config file was outside of the /etc/config path,
 470          * don't save the delta to a file, update the real file
 471          * directly.
 472          * does not modify the uci_package pointer
 473          */
 474         if (!p->has_delta)
 475                 return uci_commit(ctx, &p, false);
 476
 477         if (uci_list_empty(&p->delta))
 478                 return 0;
 479
 480         if (stat(ctx->savedir, &statbuf) < 0) {
 481                 if (stat(ctx->confdir, &statbuf) == 0) {
 482                         mkdir(ctx->savedir, statbuf.st_mode);
 483                 } else {
 484                         mkdir(ctx->savedir, UCI_DIRMODE);
 485                 }
 486         } else if ((statbuf.st_mode & S_IFMT) != S_IFDIR) {
 487                 UCI_THROW(ctx, UCI_ERR_IO);
 488         }
 489
 490         if ((asprintf(&filename, "%s/%s", ctx->savedir, p->e.name) < 0) || !filename)
 491                 UCI_THROW(ctx, UCI_ERR_MEM);
 492
 493         ctx->err = 0;
 494         UCI_TRAP_SAVE(ctx, done);
 495         f = uci_open_stream(ctx, filename, NULL, SEEK_END, true, true);
 496         UCI_TRAP_RESTORE(ctx);
 497
 498         uci_foreach_element_safe(&p->delta, tmp, e) {
 499                 struct uci_delta *h = uci_to_delta(e);
 500                 uci_delta_save(ctx, f, p->e.name, h);
 501                 uci_free_delta(h);
 502         }
 503
 504 done:
 505         uci_close_stream(f);
 506         free(filename);
 507         if (ctx->err)
 508                 UCI_THROW(ctx, ctx->err);
 509
 510         return 0;
 511 }
 512
 513