history.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 General Public License for more details.
  13  */
  14
  15 /*
  16  * This file contains the code for handling uci config history 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
  29 /* record a change that was done to a package */
  30 void
  31 uci_add_history(struct uci_context *ctx, struct uci_list *list, int cmd, const char *section, const char *option, const char *value)
  32 {
  33         struct uci_history *h;
  34         int size = strlen(section) + 1;
  35         char *ptr;
  36
  37         if (value)
  38                 size += strlen(value) + 1;
  39
  40         h = uci_alloc_element(ctx, history, option, size);
  41         ptr = uci_dataptr(h);
  42         h->cmd = cmd;
  43         h->section = strcpy(ptr, section);
  44         if (value) {
  45                 ptr += strlen(ptr) + 1;
  46                 h->value = strcpy(ptr, value);
  47         }
  48         uci_list_add(list, &h->e.list);
  49 }
  50
  51 void
  52 uci_free_history(struct uci_history *h)
  53 {
  54         if (!h)
  55                 return;
  56         if ((h->section != NULL) &&
  57                 (h->section != uci_dataptr(h))) {
  58                 free(h->section);
  59                 free(h->value);
  60         }
  61         uci_free_element(&h->e);
  62 }
  63
  64
  65 int uci_set_savedir(struct uci_context *ctx, const char *dir)
  66 {
  67         char *sdir;
  68
  69         UCI_HANDLE_ERR(ctx);
  70         UCI_ASSERT(ctx, dir != NULL);
  71
  72         sdir = uci_strdup(ctx, dir);
  73         if (ctx->savedir != uci_savedir)
  74                 free(ctx->savedir);
  75         ctx->savedir = sdir;
  76         return 0;
  77 }
  78
  79 int uci_add_history_path(struct uci_context *ctx, const char *dir)
  80 {
  81         struct uci_element *e;
  82
  83         UCI_HANDLE_ERR(ctx);
  84         UCI_ASSERT(ctx, dir != NULL);
  85         e = uci_alloc_generic(ctx, UCI_TYPE_PATH, dir, sizeof(struct uci_element));
  86         uci_list_add(&ctx->history_path, &e->list);
  87
  88         return 0;
  89 }
  90
  91 static inline int uci_parse_history_tuple(struct uci_context *ctx, char **buf, struct uci_ptr *ptr)
  92 {
  93         int c = UCI_CMD_CHANGE;
  94
  95         switch(**buf) {
  96         case '-':
  97                 c = UCI_CMD_REMOVE;
  98                 break;
  99         case '@':
 100                 c = UCI_CMD_RENAME;
 101                 break;
 102         case '+':
 103                 /* UCI_CMD_ADD is used for anonymous sections or list values */
 104                 c = UCI_CMD_ADD;
 105                 break;
 106         case '|':
 107                 c = UCI_CMD_LIST_ADD;
 108                 break;
 109         }
 110
 111         if (c != UCI_CMD_CHANGE)
 112                 *buf += 1;
 113
 114         UCI_INTERNAL(uci_parse_ptr, ctx, ptr, *buf);
 115
 116         if (!ptr->section)
 117                 goto error;
 118         if (ptr->flags & UCI_LOOKUP_EXTENDED)
 119                 goto error;
 120
 121         switch(c) {
 122         case UCI_CMD_RENAME:
 123                 if (!ptr->value || !uci_validate_name(ptr->value))
 124                         goto error;
 125                 break;
 126         case UCI_CMD_LIST_ADD:
 127                 if (!ptr->option)
 128                         goto error;
 129         }
 130
 131         return c;
 132
 133 error:
 134         UCI_THROW(ctx, UCI_ERR_INVAL);
 135         return 0;
 136 }
 137
 138 static void uci_parse_history_line(struct uci_context *ctx, struct uci_package *p, char *buf)
 139 {
 140         struct uci_element *e = NULL;
 141         struct uci_ptr ptr;
 142         int cmd;
 143
 144         cmd = uci_parse_history_tuple(ctx, &buf, &ptr);
 145         if (strcmp(ptr.package, p->e.name) != 0)
 146                 goto error;
 147
 148         if (ctx->flags & UCI_FLAG_SAVED_HISTORY)
 149                 uci_add_history(ctx, &p->saved_history, cmd, ptr.section, ptr.option, ptr.value);
 150
 151         switch(cmd) {
 152         case UCI_CMD_RENAME:
 153                 UCI_INTERNAL(uci_rename, ctx, &ptr);
 154                 break;
 155         case UCI_CMD_REMOVE:
 156                 UCI_INTERNAL(uci_delete, ctx, &ptr);
 157                 break;
 158         case UCI_CMD_LIST_ADD:
 159                 UCI_INTERNAL(uci_add_list, ctx, &ptr);
 160                 break;
 161         case UCI_CMD_ADD:
 162         case UCI_CMD_CHANGE:
 163                 UCI_INTERNAL(uci_set, ctx, p, ptr.section, ptr.option, ptr.value, &e);
 164                 if (!ptr.option && e && (cmd == UCI_CMD_ADD))
 165                         uci_to_section(e)->anonymous = true;
 166                 break;
 167         }
 168         return;
 169 error:
 170         UCI_THROW(ctx, UCI_ERR_PARSE);
 171 }
 172
 173 /* returns the number of changes that were successfully parsed */
 174 static int uci_parse_history(struct uci_context *ctx, FILE *stream, struct uci_package *p)
 175 {
 176         struct uci_parse_context *pctx;
 177         int changes = 0;
 178
 179         /* make sure no memory from previous parse attempts is leaked */
 180         uci_cleanup(ctx);
 181
 182         pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 183         ctx->pctx = pctx;
 184         pctx->file = stream;
 185
 186         while (!feof(pctx->file)) {
 187                 uci_getln(ctx, 0);
 188                 if (!pctx->buf[0])
 189                         continue;
 190
 191                 /*
 192                  * ignore parse errors in single lines, we want to preserve as much
 193                  * history as possible
 194                  */
 195                 UCI_TRAP_SAVE(ctx, error);
 196                 uci_parse_history_line(ctx, p, pctx->buf);
 197                 UCI_TRAP_RESTORE(ctx);
 198                 changes++;
 199 error:
 200                 continue;
 201         }
 202
 203         /* no error happened, we can get rid of the parser context now */
 204         uci_cleanup(ctx);
 205         return changes;
 206 }
 207
 208 /* returns the number of changes that were successfully parsed */
 209 static int uci_load_history_file(struct uci_context *ctx, struct uci_package *p, char *filename, FILE **f, bool flush)
 210 {
 211         FILE *stream = NULL;
 212         int changes = 0;
 213
 214         UCI_TRAP_SAVE(ctx, done);
 215         stream = uci_open_stream(ctx, filename, SEEK_SET, flush, false);
 216         if (p)
 217                 changes = uci_parse_history(ctx, stream, p);
 218         UCI_TRAP_RESTORE(ctx);
 219 done:
 220         if (f)
 221                 *f = stream;
 222         else if (stream)
 223                 uci_close_stream(stream);
 224         return changes;
 225 }
 226
 227 /* returns the number of changes that were successfully parsed */
 228 static int uci_load_history(struct uci_context *ctx, struct uci_package *p, bool flush)
 229 {
 230         struct uci_element *e;
 231         char *filename = NULL;
 232         FILE *f = NULL;
 233         int changes = 0;
 234
 235         if (!p->has_history)
 236                 return 0;
 237
 238         uci_foreach_element(&ctx->history_path, e) {
 239                 if ((asprintf(&filename, "%s/%s", e->name, p->e.name) < 0) || !filename)
 240                         UCI_THROW(ctx, UCI_ERR_MEM);
 241
 242                 uci_load_history_file(ctx, p, filename, NULL, false);
 243                 free(filename);
 244         }
 245
 246         if ((asprintf(&filename, "%s/%s", ctx->savedir, p->e.name) < 0) || !filename)
 247                 UCI_THROW(ctx, UCI_ERR_MEM);
 248
 249         changes = uci_load_history_file(ctx, p, filename, &f, flush);
 250         if (flush && f && (changes > 0)) {
 251                 rewind(f);
 252                 ftruncate(fileno(f), 0);
 253         }
 254         if (filename)
 255                 free(filename);
 256         uci_close_stream(f);
 257         ctx->err = 0;
 258         return changes;
 259 }
 260
 261 static void uci_filter_history(struct uci_context *ctx, const char *name, const char *section, const char *option)
 262 {
 263         struct uci_parse_context *pctx;
 264         struct uci_element *e, *tmp;
 265         struct uci_list list;
 266         char *filename = NULL;
 267         struct uci_ptr ptr;
 268         FILE *f = NULL;
 269
 270         uci_list_init(&list);
 271         uci_alloc_parse_context(ctx);
 272         pctx = ctx->pctx;
 273
 274         if ((asprintf(&filename, "%s/%s", ctx->savedir, name) < 0) || !filename)
 275                 UCI_THROW(ctx, UCI_ERR_MEM);
 276
 277         UCI_TRAP_SAVE(ctx, done);
 278         f = uci_open_stream(ctx, filename, SEEK_SET, true, false);
 279         pctx->file = f;
 280         while (!feof(f)) {
 281                 struct uci_element *e;
 282                 char *buf;
 283
 284                 uci_getln(ctx, 0);
 285                 buf = pctx->buf;
 286                 if (!buf[0])
 287                         continue;
 288
 289                 /* NB: need to allocate the element before the call to
 290                  * uci_parse_history_tuple, otherwise the original string
 291                  * gets modified before it is saved */
 292                 e = uci_alloc_generic(ctx, UCI_TYPE_HISTORY, pctx->buf, sizeof(struct uci_element));
 293                 uci_list_add(&list, &e->list);
 294
 295                 uci_parse_history_tuple(ctx, &buf, &ptr);
 296                 if (section) {
 297                         if (!ptr.section || (strcmp(section, ptr.section) != 0))
 298                                 continue;
 299                 }
 300                 if (option) {
 301                         if (!ptr.option || (strcmp(option, ptr.option) != 0))
 302                                 continue;
 303                 }
 304                 /* match, drop this element again */
 305                 uci_free_element(e);
 306         }
 307
 308         /* rebuild the history file */
 309         rewind(f);
 310         ftruncate(fileno(f), 0);
 311         uci_foreach_element_safe(&list, tmp, e) {
 312                 fprintf(f, "%s\n", e->name);
 313                 uci_free_element(e);
 314         }
 315         UCI_TRAP_RESTORE(ctx);
 316
 317 done:
 318         if (filename)
 319                 free(filename);
 320         uci_close_stream(f);
 321         uci_foreach_element_safe(&list, tmp, e) {
 322                 uci_free_element(e);
 323         }
 324         uci_cleanup(ctx);
 325 }
 326
 327 int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr)
 328 {
 329         char *package = NULL;
 330         char *section = NULL;
 331         char *option = NULL;
 332
 333         UCI_HANDLE_ERR(ctx);
 334         expand_ptr(ctx, ptr, true);
 335         UCI_ASSERT(ctx, ptr->p->has_history);
 336
 337         /*
 338          * - flush unwritten changes
 339          * - save the package name
 340          * - unload the package
 341          * - filter the history
 342          * - reload the package
 343          */
 344         UCI_TRAP_SAVE(ctx, error);
 345         UCI_INTERNAL(uci_save, ctx, ptr->p);
 346
 347         /* NB: need to clone package, section and option names,
 348          * as they may get freed on uci_free_package() */
 349         package = uci_strdup(ctx, ptr->p->e.name);
 350         section = uci_strdup(ctx, ptr->section);
 351         option = uci_strdup(ctx, ptr->option);
 352
 353         uci_free_package(&ptr->p);
 354         uci_filter_history(ctx, package, section, option);
 355
 356         UCI_INTERNAL(uci_load, ctx, package, &ptr->p);
 357         UCI_TRAP_RESTORE(ctx);
 358         ctx->err = 0;
 359
 360 error:
 361         if (package)
 362                 free(package);
 363         if (section)
 364                 free(section);
 365         if (option)
 366                 free(option);
 367         if (ctx->err)
 368                 UCI_THROW(ctx, ctx->err);
 369         return 0;
 370 }
 371
 372 int uci_save(struct uci_context *ctx, struct uci_package *p)
 373 {
 374         FILE *f = NULL;
 375         char *filename = NULL;
 376         struct uci_element *e, *tmp;
 377         struct stat statbuf;
 378
 379         UCI_HANDLE_ERR(ctx);
 380         UCI_ASSERT(ctx, p != NULL);
 381
 382         /*
 383          * if the config file was outside of the /etc/config path,
 384          * don't save the history to a file, update the real file
 385          * directly.
 386          * does not modify the uci_package pointer
 387          */
 388         if (!p->has_history)
 389                 return uci_commit(ctx, &p, false);
 390
 391         if (uci_list_empty(&p->history))
 392                 return 0;
 393
 394         if (stat(ctx->savedir, &statbuf) < 0)
 395                 mkdir(ctx->savedir, UCI_DIRMODE);
 396         else if ((statbuf.st_mode & S_IFMT) != S_IFDIR)
 397                 UCI_THROW(ctx, UCI_ERR_IO);
 398
 399         if ((asprintf(&filename, "%s/%s", ctx->savedir, p->e.name) < 0) || !filename)
 400                 UCI_THROW(ctx, UCI_ERR_MEM);
 401
 402         ctx->err = 0;
 403         UCI_TRAP_SAVE(ctx, done);
 404         f = uci_open_stream(ctx, filename, SEEK_END, true, true);
 405         UCI_TRAP_RESTORE(ctx);
 406
 407         uci_foreach_element_safe(&p->history, tmp, e) {
 408                 struct uci_history *h = uci_to_history(e);
 409                 char *prefix = "";
 410
 411                 switch(h->cmd) {
 412                 case UCI_CMD_REMOVE:
 413                         prefix = "-";
 414                         break;
 415                 case UCI_CMD_RENAME:
 416                         prefix = "@";
 417                         break;
 418                 case UCI_CMD_ADD:
 419                         prefix = "+";
 420                         break;
 421                 case UCI_CMD_LIST_ADD:
 422                         prefix = "|";
 423                         break;
 424                 default:
 425                         break;
 426                 }
 427
 428                 fprintf(f, "%s%s.%s", prefix, p->e.name, h->section);
 429                 if (e->name)
 430                         fprintf(f, ".%s", e->name);
 431
 432                 if (h->cmd == UCI_CMD_REMOVE)
 433                         fprintf(f, "\n");
 434                 else
 435                         fprintf(f, "=%s\n", h->value);
 436                 uci_free_history(h);
 437         }
 438
 439 done:
 440         uci_close_stream(f);
 441         if (filename)
 442                 free(filename);
 443         if (ctx->err)
 444                 UCI_THROW(ctx, ctx->err);
 445
 446         return 0;
 447 }
 448
 449