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