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