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
 103         UCI_HANDLE_ERR(ctx);
 104         UCI_ASSERT(ctx, dir != NULL);
 105
 106         sdir = uci_strdup(ctx, dir);
 107         if (ctx->savedir != uci_savedir)
 108                 free(ctx->savedir);
 109         ctx->savedir = sdir;
 110         return 0;
 111 }
 112
 113 int uci_add_delta_path(struct uci_context *ctx, const char *dir)
 114 {
 115         struct uci_element *e;
 116
 117         UCI_HANDLE_ERR(ctx);
 118         UCI_ASSERT(ctx, dir != NULL);
 119         if (!strcmp(dir, ctx->savedir))
 120                 return -1;
 121         e = uci_alloc_generic(ctx, UCI_TYPE_PATH, dir, sizeof(struct uci_element));
 122         uci_list_add(&ctx->delta_path, &e->list);
 123
 124         return 0;
 125 }
 126
 127 char const uci_command_char[] = {
 128         [UCI_CMD_ADD] = '+',
 129         [UCI_CMD_REMOVE] = '-',
 130         [UCI_CMD_CHANGE] = 0,
 131         [UCI_CMD_RENAME] = '@',
 132         [UCI_CMD_REORDER] = '^',
 133         [UCI_CMD_LIST_ADD] = '|',
 134         [UCI_CMD_LIST_DEL] = '~'
 135 };
 136
 137 static inline int uci_parse_delta_tuple(struct uci_context *ctx, struct uci_ptr *ptr)
 138 {
 139         struct uci_parse_context *pctx = ctx->pctx;
 140         char *str = pctx_cur_str(pctx), *arg;
 141         int c;
 142
 143         UCI_INTERNAL(uci_parse_argument, ctx, ctx->pctx->file, &str, &arg);
 144         for (c = 0; c <= __UCI_CMD_LAST; c++) {
 145                 if (uci_command_char[c] == *arg)
 146                         break;
 147         }
 148         if (c > __UCI_CMD_LAST)
 149                 c = UCI_CMD_CHANGE;
 150
 151         if (c != UCI_CMD_CHANGE)
 152                 arg += 1;
 153
 154         UCI_INTERNAL(uci_parse_ptr, ctx, ptr, arg);
 155
 156         if (!ptr->section)
 157                 goto error;
 158         if (ptr->flags & UCI_LOOKUP_EXTENDED)
 159                 goto error;
 160
 161         switch(c) {
 162         case UCI_CMD_REORDER:
 163                 if (!ptr->value || ptr->option)
 164                         goto error;
 165                 break;
 166         case UCI_CMD_RENAME:
 167                 if (!ptr->value || !uci_validate_name(ptr->value))
 168                         goto error;
 169                 break;
 170         case UCI_CMD_LIST_ADD:
 171                 if (!ptr->option)
 172                         goto error;
 173         case UCI_CMD_LIST_DEL:
 174                 if (!ptr->option)
 175                         goto error;
 176         }
 177
 178         return c;
 179
 180 error:
 181         UCI_THROW(ctx, UCI_ERR_INVAL);
 182         return 0;
 183 }
 184
 185 static void uci_parse_delta_line(struct uci_context *ctx, struct uci_package *p)
 186 {
 187         struct uci_element *e = NULL;
 188         struct uci_ptr ptr;
 189         int cmd;
 190
 191         cmd = uci_parse_delta_tuple(ctx, &ptr);
 192         if (strcmp(ptr.package, p->e.name) != 0)
 193                 goto error;
 194
 195         if (ctx->flags & UCI_FLAG_SAVED_DELTA)
 196                 uci_add_delta(ctx, &p->saved_delta, cmd, ptr.section, ptr.option, ptr.value);
 197
 198         switch(cmd) {
 199         case UCI_CMD_REORDER:
 200                 uci_expand_ptr(ctx, &ptr, true);
 201                 if (!ptr.s)
 202                         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 203                 UCI_INTERNAL(uci_reorder_section, ctx, ptr.s, strtoul(ptr.value, NULL, 10));
 204                 break;
 205         case UCI_CMD_RENAME:
 206                 UCI_INTERNAL(uci_rename, ctx, &ptr);
 207                 break;
 208         case UCI_CMD_REMOVE:
 209                 UCI_INTERNAL(uci_delete, ctx, &ptr);
 210                 break;
 211         case UCI_CMD_LIST_ADD:
 212                 UCI_INTERNAL(uci_add_list, ctx, &ptr);
 213                 break;
 214         case UCI_CMD_LIST_DEL:
 215                 UCI_INTERNAL(uci_del_list, ctx, &ptr);
 216                 break;
 217         case UCI_CMD_ADD:
 218         case UCI_CMD_CHANGE:
 219                 UCI_INTERNAL(uci_set, ctx, &ptr);
 220                 e = ptr.last;
 221                 if (!ptr.option && e && (cmd == UCI_CMD_ADD))
 222                         uci_to_section(e)->anonymous = true;
 223                 break;
 224         }
 225         return;
 226 error:
 227         UCI_THROW(ctx, UCI_ERR_PARSE);
 228 }
 229
 230 /* returns the number of changes that were successfully parsed */
 231 static int uci_parse_delta(struct uci_context *ctx, FILE *stream, struct uci_package *p)
 232 {
 233         struct uci_parse_context *pctx;
 234         int changes = 0;
 235
 236         /* make sure no memory from previous parse attempts is leaked */
 237         uci_cleanup(ctx);
 238
 239         pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 240         ctx->pctx = pctx;
 241         pctx->file = stream;
 242
 243         while (!feof(pctx->file)) {
 244                 pctx->pos = 0;
 245                 uci_getln(ctx, 0);
 246                 if (!pctx->buf[0])
 247                         continue;
 248
 249                 /*
 250                  * ignore parse errors in single lines, we want to preserve as much
 251                  * delta as possible
 252                  */
 253                 UCI_TRAP_SAVE(ctx, error);
 254                 uci_parse_delta_line(ctx, p);
 255                 UCI_TRAP_RESTORE(ctx);
 256                 changes++;
 257 error:
 258                 continue;
 259         }
 260
 261         /* no error happened, we can get rid of the parser context now */
 262         uci_cleanup(ctx);
 263         return changes;
 264 }
 265
 266 /* returns the number of changes that were successfully parsed */
 267 static int uci_load_delta_file(struct uci_context *ctx, struct uci_package *p, char *filename, FILE **f, bool flush)
 268 {
 269         FILE *stream = NULL;
 270         int changes = 0;
 271
 272         UCI_TRAP_SAVE(ctx, done);
 273         stream = uci_open_stream(ctx, filename, NULL, SEEK_SET, flush, false);
 274         if (p)
 275                 changes = uci_parse_delta(ctx, stream, p);
 276         UCI_TRAP_RESTORE(ctx);
 277 done:
 278         if (f)
 279                 *f = stream;
 280         else if (stream)
 281                 uci_close_stream(stream);
 282         return changes;
 283 }
 284
 285 /* returns the number of changes that were successfully parsed */
 286 __private int uci_load_delta(struct uci_context *ctx, struct uci_package *p, bool flush)
 287 {
 288         struct uci_element *e;
 289         char *filename = NULL;
 290         FILE *f = NULL;
 291         int changes = 0;
 292
 293         if (!p->has_delta)
 294                 return 0;
 295
 296         uci_foreach_element(&ctx->delta_path, e) {
 297                 if ((asprintf(&filename, "%s/%s", e->name, p->e.name) < 0) || !filename)
 298                         UCI_THROW(ctx, UCI_ERR_MEM);
 299
 300                 uci_load_delta_file(ctx, p, filename, NULL, false);
 301                 free(filename);
 302         }
 303
 304         if ((asprintf(&filename, "%s/%s", ctx->savedir, p->e.name) < 0) || !filename)
 305                 UCI_THROW(ctx, UCI_ERR_MEM);
 306
 307         changes = uci_load_delta_file(ctx, p, filename, &f, flush);
 308         if (flush && f && (changes > 0)) {
 309                 rewind(f);
 310                 if (ftruncate(fileno(f), 0) < 0) {
 311                         uci_close_stream(f);
 312                         UCI_THROW(ctx, UCI_ERR_IO);
 313                 }
 314         }
 315         free(filename);
 316         uci_close_stream(f);
 317         ctx->err = 0;
 318         return changes;
 319 }
 320
 321 static void uci_filter_delta(struct uci_context *ctx, const char *name, const char *section, const char *option)
 322 {
 323         struct uci_parse_context *pctx;
 324         struct uci_element *e, *tmp;
 325         struct uci_list list;
 326         char *filename = NULL;
 327         struct uci_ptr ptr;
 328         FILE *f = NULL;
 329
 330         uci_list_init(&list);
 331         uci_alloc_parse_context(ctx);
 332         pctx = ctx->pctx;
 333
 334         if ((asprintf(&filename, "%s/%s", ctx->savedir, name) < 0) || !filename)
 335                 UCI_THROW(ctx, UCI_ERR_MEM);
 336
 337         UCI_TRAP_SAVE(ctx, done);
 338         f = uci_open_stream(ctx, filename, NULL, SEEK_SET, true, false);
 339         pctx->file = f;
 340         while (!feof(f)) {
 341                 enum uci_command c;
 342                 bool match;
 343
 344                 pctx->pos = 0;
 345                 uci_getln(ctx, 0);
 346                 if (!pctx->buf[0])
 347                         continue;
 348
 349                 c = uci_parse_delta_tuple(ctx, &ptr);
 350                 match = true;
 351                 if (section) {
 352                         if (!ptr.section || (strcmp(section, ptr.section) != 0))
 353                                 match = false;
 354                 }
 355                 if (match && option) {
 356                         if (!ptr.option || (strcmp(option, ptr.option) != 0))
 357                                 match = false;
 358                 }
 359
 360                 if (!match) {
 361                         uci_add_delta(ctx, &list, c,
 362                                 ptr.section, ptr.option, ptr.value);
 363                 }
 364         }
 365
 366         /* rebuild the delta file */
 367         rewind(f);
 368         if (ftruncate(fileno(f), 0) < 0)
 369                 UCI_THROW(ctx, UCI_ERR_IO);
 370         uci_foreach_element_safe(&list, tmp, e) {
 371                 struct uci_delta *h = uci_to_delta(e);
 372                 uci_delta_save(ctx, f, name, h);
 373                 uci_free_delta(h);
 374         }
 375         UCI_TRAP_RESTORE(ctx);
 376
 377 done:
 378         free(filename);
 379         uci_close_stream(pctx->file);
 380         uci_foreach_element_safe(&list, tmp, e) {
 381                 uci_free_delta(uci_to_delta(e));
 382         }
 383         uci_cleanup(ctx);
 384 }
 385
 386 int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr)
 387 {
 388         char *package = NULL;
 389         char *section = NULL;
 390         char *option = NULL;
 391
 392         UCI_HANDLE_ERR(ctx);
 393         uci_expand_ptr(ctx, ptr, false);
 394         UCI_ASSERT(ctx, ptr->p->has_delta);
 395
 396         /*
 397          * - flush unwritten changes
 398          * - save the package name
 399          * - unload the package
 400          * - filter the delta
 401          * - reload the package
 402          */
 403         UCI_TRAP_SAVE(ctx, error);
 404         UCI_INTERNAL(uci_save, ctx, ptr->p);
 405
 406         /* NB: need to clone package, section and option names,
 407          * as they may get freed on uci_free_package() */
 408         package = uci_strdup(ctx, ptr->p->e.name);
 409         if (ptr->section)
 410                 section = uci_strdup(ctx, ptr->section);
 411         if (ptr->option)
 412                 option = uci_strdup(ctx, ptr->option);
 413
 414         uci_free_package(&ptr->p);
 415         uci_filter_delta(ctx, package, section, option);
 416
 417         UCI_INTERNAL(uci_load, ctx, package, &ptr->p);
 418         UCI_TRAP_RESTORE(ctx);
 419         ctx->err = 0;
 420
 421 error:
 422         free(package);
 423         free(section);
 424         free(option);
 425         if (ctx->err)
 426                 UCI_THROW(ctx, ctx->err);
 427         return 0;
 428 }
 429
 430 int uci_save(struct uci_context *ctx, struct uci_package *p)
 431 {
 432         FILE *f = NULL;
 433         char *filename = NULL;
 434         struct uci_element *e, *tmp;
 435         struct stat statbuf;
 436
 437         UCI_HANDLE_ERR(ctx);
 438         UCI_ASSERT(ctx, p != NULL);
 439
 440         /*
 441          * if the config file was outside of the /etc/config path,
 442          * don't save the delta to a file, update the real file
 443          * directly.
 444          * does not modify the uci_package pointer
 445          */
 446         if (!p->has_delta)
 447                 return uci_commit(ctx, &p, false);
 448
 449         if (uci_list_empty(&p->delta))
 450                 return 0;
 451
 452         if (stat(ctx->savedir, &statbuf) < 0) {
 453                 if (stat(ctx->confdir, &statbuf) == 0) {
 454                         mkdir(ctx->savedir, statbuf.st_mode);
 455                 } else {
 456                         mkdir(ctx->savedir, UCI_DIRMODE);
 457                 }
 458         } else if ((statbuf.st_mode & S_IFMT) != S_IFDIR) {
 459                 UCI_THROW(ctx, UCI_ERR_IO);
 460         }
 461
 462         if ((asprintf(&filename, "%s/%s", ctx->savedir, p->e.name) < 0) || !filename)
 463                 UCI_THROW(ctx, UCI_ERR_MEM);
 464
 465         ctx->err = 0;
 466         UCI_TRAP_SAVE(ctx, done);
 467         f = uci_open_stream(ctx, filename, NULL, SEEK_END, true, true);
 468         UCI_TRAP_RESTORE(ctx);
 469
 470         uci_foreach_element_safe(&p->delta, tmp, e) {
 471                 struct uci_delta *h = uci_to_delta(e);
 472                 uci_delta_save(ctx, f, p->e.name, h);
 473                 uci_free_delta(h);
 474         }
 475
 476 done:
 477         uci_close_stream(f);
 478         free(filename);
 479         if (ctx->err)
 480                 UCI_THROW(ctx, ctx->err);
 481
 482         return 0;
 483 }
 484
 485