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                 UCI_INTERNAL(uci_add_delta_path, ctx, dir);
 118         else
 119                 uci_list_add(&ctx->delta_path, &e->list);
 120
 121         sdir = uci_strdup(ctx, dir);
 122         if (ctx->savedir != uci_savedir)
 123                 free(ctx->savedir);
 124         ctx->savedir = sdir;
 125         return 0;
 126 }
 127
 128 int uci_add_delta_path(struct uci_context *ctx, const char *dir)
 129 {
 130         struct uci_element *e;
 131         struct uci_list *savedir;
 132
 133         UCI_HANDLE_ERR(ctx);
 134         UCI_ASSERT(ctx, dir != NULL);
 135
 136         /* Duplicate delta path is not allowed */
 137         uci_foreach_element(&ctx->delta_path, e) {
 138                 if (!strcmp(e->name, dir))
 139                         UCI_THROW(ctx, UCI_ERR_DUPLICATE);
 140         }
 141
 142         e = uci_alloc_generic(ctx, UCI_TYPE_PATH, dir, sizeof(struct uci_element));
 143         /* Keep savedir at the end of ctx->delta_path list */
 144         savedir = ctx->delta_path.prev;
 145         uci_list_insert(savedir->prev, &e->list);
 146
 147         return 0;
 148 }
 149
 150 char const uci_command_char[] = {
 151         [UCI_CMD_ADD] = '+',
 152         [UCI_CMD_REMOVE] = '-',
 153         [UCI_CMD_CHANGE] = 0,
 154         [UCI_CMD_RENAME] = '@',
 155         [UCI_CMD_REORDER] = '^',
 156         [UCI_CMD_LIST_ADD] = '|',
 157         [UCI_CMD_LIST_DEL] = '~'
 158 };
 159
 160 static inline int uci_parse_delta_tuple(struct uci_context *ctx, struct uci_ptr *ptr)
 161 {
 162         struct uci_parse_context *pctx = ctx->pctx;
 163         char *str = pctx_cur_str(pctx), *arg;
 164         int c;
 165
 166         UCI_INTERNAL(uci_parse_argument, ctx, ctx->pctx->file, &str, &arg);
 167         for (c = 0; c <= __UCI_CMD_LAST; c++) {
 168                 if (uci_command_char[c] == *arg)
 169                         break;
 170         }
 171         if (c > __UCI_CMD_LAST)
 172                 c = UCI_CMD_CHANGE;
 173
 174         if (c != UCI_CMD_CHANGE)
 175                 arg += 1;
 176
 177         UCI_INTERNAL(uci_parse_ptr, ctx, ptr, arg);
 178
 179         if (!ptr->section)
 180                 goto error;
 181         if (ptr->flags & UCI_LOOKUP_EXTENDED)
 182                 goto error;
 183
 184         switch(c) {
 185         case UCI_CMD_REORDER:
 186                 if (!ptr->value || ptr->option)
 187                         goto error;
 188                 break;
 189         case UCI_CMD_RENAME:
 190                 if (!ptr->value || !uci_validate_name(ptr->value))
 191                         goto error;
 192                 break;
 193         case UCI_CMD_LIST_ADD:
 194                 if (!ptr->option)
 195                         goto error;
 196         case UCI_CMD_LIST_DEL:
 197                 if (!ptr->option)
 198                         goto error;
 199         }
 200
 201         return c;
 202
 203 error:
 204         UCI_THROW(ctx, UCI_ERR_INVAL);
 205         return 0;
 206 }
 207
 208 static void uci_parse_delta_line(struct uci_context *ctx, struct uci_package *p)
 209 {
 210         struct uci_element *e = NULL;
 211         struct uci_ptr ptr;
 212         int cmd;
 213
 214         cmd = uci_parse_delta_tuple(ctx, &ptr);
 215         if (strcmp(ptr.package, p->e.name) != 0)
 216                 goto error;
 217
 218         if (ctx->flags & UCI_FLAG_SAVED_DELTA)
 219                 uci_add_delta(ctx, &p->saved_delta, cmd, ptr.section, ptr.option, ptr.value);
 220
 221         switch(cmd) {
 222         case UCI_CMD_REORDER:
 223                 uci_expand_ptr(ctx, &ptr, true);
 224                 if (!ptr.s)
 225                         UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 226                 UCI_INTERNAL(uci_reorder_section, ctx, ptr.s, strtoul(ptr.value, NULL, 10));
 227                 break;
 228         case UCI_CMD_RENAME:
 229                 UCI_INTERNAL(uci_rename, ctx, &ptr);
 230                 break;
 231         case UCI_CMD_REMOVE:
 232                 UCI_INTERNAL(uci_delete, ctx, &ptr);
 233                 break;
 234         case UCI_CMD_LIST_ADD:
 235                 UCI_INTERNAL(uci_add_list, ctx, &ptr);
 236                 break;
 237         case UCI_CMD_LIST_DEL:
 238                 UCI_INTERNAL(uci_del_list, ctx, &ptr);
 239                 break;
 240         case UCI_CMD_ADD:
 241         case UCI_CMD_CHANGE:
 242                 UCI_INTERNAL(uci_set, ctx, &ptr);
 243                 e = ptr.last;
 244                 if (!ptr.option && e && (cmd == UCI_CMD_ADD))
 245                         uci_to_section(e)->anonymous = true;
 246                 break;
 247         }
 248         return;
 249 error:
 250         UCI_THROW(ctx, UCI_ERR_PARSE);
 251 }
 252
 253 /* returns the number of changes that were successfully parsed */
 254 static int uci_parse_delta(struct uci_context *ctx, FILE *stream, struct uci_package *p)
 255 {
 256         struct uci_parse_context *pctx;
 257         int changes = 0;
 258
 259         /* make sure no memory from previous parse attempts is leaked */
 260         uci_cleanup(ctx);
 261
 262         pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 263         ctx->pctx = pctx;
 264         pctx->file = stream;
 265
 266         while (!feof(pctx->file)) {
 267                 pctx->pos = 0;
 268                 uci_getln(ctx, 0);
 269                 if (!pctx->buf[0])
 270                         continue;
 271
 272                 /*
 273                  * ignore parse errors in single lines, we want to preserve as much
 274                  * delta as possible
 275                  */
 276                 UCI_TRAP_SAVE(ctx, error);
 277                 uci_parse_delta_line(ctx, p);
 278                 UCI_TRAP_RESTORE(ctx);
 279                 changes++;
 280 error:
 281                 continue;
 282         }
 283
 284         /* no error happened, we can get rid of the parser context now */
 285         uci_cleanup(ctx);
 286         return changes;
 287 }
 288
 289 /* returns the number of changes that were successfully parsed */
 290 static int uci_load_delta_file(struct uci_context *ctx, struct uci_package *p, char *filename, FILE **f, bool flush)
 291 {
 292         FILE *stream = NULL;
 293         int changes = 0;
 294
 295         UCI_TRAP_SAVE(ctx, done);
 296         stream = uci_open_stream(ctx, filename, NULL, SEEK_SET, flush, false);
 297         if (p)
 298                 changes = uci_parse_delta(ctx, stream, p);
 299         UCI_TRAP_RESTORE(ctx);
 300 done:
 301         if (f)
 302                 *f = stream;
 303         else if (stream)
 304                 uci_close_stream(stream);
 305         return changes;
 306 }
 307
 308 /* returns the number of changes that were successfully parsed */
 309 __private int uci_load_delta(struct uci_context *ctx, struct uci_package *p, bool flush)
 310 {
 311         struct uci_element *e;
 312         char *filename = NULL;
 313         FILE *f = NULL;
 314         int changes = 0;
 315
 316         if (!p->has_delta)
 317                 return 0;
 318
 319         uci_foreach_element(&ctx->delta_path, e) {
 320                 if ((asprintf(&filename, "%s/%s", e->name, p->e.name) < 0) || !filename)
 321                         UCI_THROW(ctx, UCI_ERR_MEM);
 322
 323                 changes += uci_load_delta_file(ctx, p, filename, NULL, false);
 324                 free(filename);
 325         }
 326
 327         if ((asprintf(&filename, "%s/%s", ctx->savedir, p->e.name) < 0) || !filename)
 328                 UCI_THROW(ctx, UCI_ERR_MEM);
 329         UCI_TRAP_SAVE(ctx, done);
 330         f = uci_open_stream(ctx, filename, NULL, SEEK_SET, flush, false);
 331         UCI_TRAP_RESTORE(ctx);
 332
 333         if (flush && f && (changes > 0)) {
 334                 if (ftruncate(fileno(f), 0) < 0) {
 335                         free(filename);
 336                         uci_close_stream(f);
 337                         UCI_THROW(ctx, UCI_ERR_IO);
 338                 }
 339         }
 340
 341 done:
 342         free(filename);
 343         uci_close_stream(f);
 344         ctx->err = 0;
 345         return changes;
 346 }
 347
 348 static void uci_filter_delta(struct uci_context *ctx, const char *name, const char *section, const char *option)
 349 {
 350         struct uci_parse_context *pctx;
 351         struct uci_element *e, *tmp;
 352         struct uci_list list;
 353         char *filename = NULL;
 354         struct uci_ptr ptr;
 355         FILE *f = NULL;
 356
 357         uci_list_init(&list);
 358         uci_alloc_parse_context(ctx);
 359         pctx = ctx->pctx;
 360
 361         if ((asprintf(&filename, "%s/%s", ctx->savedir, name) < 0) || !filename)
 362                 UCI_THROW(ctx, UCI_ERR_MEM);
 363
 364         UCI_TRAP_SAVE(ctx, done);
 365         f = uci_open_stream(ctx, filename, NULL, SEEK_SET, true, false);
 366         pctx->file = f;
 367         while (!feof(f)) {
 368                 enum uci_command c;
 369                 bool match;
 370
 371                 pctx->pos = 0;
 372                 uci_getln(ctx, 0);
 373                 if (!pctx->buf[0])
 374                         continue;
 375
 376                 c = uci_parse_delta_tuple(ctx, &ptr);
 377                 match = true;
 378                 if (section) {
 379                         if (!ptr.section || (strcmp(section, ptr.section) != 0))
 380                                 match = false;
 381                 }
 382                 if (match && option) {
 383                         if (!ptr.option || (strcmp(option, ptr.option) != 0))
 384                                 match = false;
 385                 }
 386
 387                 if (!match) {
 388                         uci_add_delta(ctx, &list, c,
 389                                 ptr.section, ptr.option, ptr.value);
 390                 }
 391         }
 392
 393         /* rebuild the delta file */
 394         rewind(f);
 395         if (ftruncate(fileno(f), 0) < 0)
 396                 UCI_THROW(ctx, UCI_ERR_IO);
 397         uci_foreach_element_safe(&list, tmp, e) {
 398                 struct uci_delta *h = uci_to_delta(e);
 399                 uci_delta_save(ctx, f, name, h);
 400                 uci_free_delta(h);
 401         }
 402         UCI_TRAP_RESTORE(ctx);
 403
 404 done:
 405         free(filename);
 406         uci_close_stream(pctx->file);
 407         uci_foreach_element_safe(&list, tmp, e) {
 408                 uci_free_delta(uci_to_delta(e));
 409         }
 410         uci_cleanup(ctx);
 411 }
 412
 413 int uci_revert(struct uci_context *ctx, struct uci_ptr *ptr)
 414 {
 415         char *package = NULL;
 416         char *section = NULL;
 417         char *option = NULL;
 418
 419         UCI_HANDLE_ERR(ctx);
 420         uci_expand_ptr(ctx, ptr, false);
 421         UCI_ASSERT(ctx, ptr->p->has_delta);
 422
 423         /*
 424          * - flush unwritten changes
 425          * - save the package name
 426          * - unload the package
 427          * - filter the delta
 428          * - reload the package
 429          */
 430         UCI_TRAP_SAVE(ctx, error);
 431         UCI_INTERNAL(uci_save, ctx, ptr->p);
 432
 433         /* NB: need to clone package, section and option names,
 434          * as they may get freed on uci_free_package() */
 435         package = uci_strdup(ctx, ptr->p->e.name);
 436         if (ptr->section)
 437                 section = uci_strdup(ctx, ptr->section);
 438         if (ptr->option)
 439                 option = uci_strdup(ctx, ptr->option);
 440
 441         uci_free_package(&ptr->p);
 442         uci_filter_delta(ctx, package, section, option);
 443
 444         UCI_INTERNAL(uci_load, ctx, package, &ptr->p);
 445         UCI_TRAP_RESTORE(ctx);
 446         ctx->err = 0;
 447
 448 error:
 449         free(package);
 450         free(section);
 451         free(option);
 452         if (ctx->err)
 453                 UCI_THROW(ctx, ctx->err);
 454         return 0;
 455 }
 456
 457 int uci_save(struct uci_context *ctx, struct uci_package *p)
 458 {
 459         FILE *f = NULL;
 460         char *filename = NULL;
 461         struct uci_element *e, *tmp;
 462         struct stat statbuf;
 463
 464         UCI_HANDLE_ERR(ctx);
 465         UCI_ASSERT(ctx, p != NULL);
 466
 467         /*
 468          * if the config file was outside of the /etc/config path,
 469          * don't save the delta to a file, update the real file
 470          * directly.
 471          * does not modify the uci_package pointer
 472          */
 473         if (!p->has_delta)
 474                 return uci_commit(ctx, &p, false);
 475
 476         if (uci_list_empty(&p->delta))
 477                 return 0;
 478
 479         if (stat(ctx->savedir, &statbuf) < 0) {
 480                 if (stat(ctx->confdir, &statbuf) == 0) {
 481                         mkdir(ctx->savedir, statbuf.st_mode);
 482                 } else {
 483                         mkdir(ctx->savedir, UCI_DIRMODE);
 484                 }
 485         } else if ((statbuf.st_mode & S_IFMT) != S_IFDIR) {
 486                 UCI_THROW(ctx, UCI_ERR_IO);
 487         }
 488
 489         if ((asprintf(&filename, "%s/%s", ctx->savedir, p->e.name) < 0) || !filename)
 490                 UCI_THROW(ctx, UCI_ERR_MEM);
 491
 492         ctx->err = 0;
 493         UCI_TRAP_SAVE(ctx, done);
 494         f = uci_open_stream(ctx, filename, NULL, SEEK_END, true, true);
 495         UCI_TRAP_RESTORE(ctx);
 496
 497         uci_foreach_element_safe(&p->delta, tmp, e) {
 498                 struct uci_delta *h = uci_to_delta(e);
 499                 uci_delta_save(ctx, f, p->e.name, h);
 500                 uci_free_delta(h);
 501         }
 502
 503 done:
 504         uci_close_stream(f);
 505         free(filename);
 506         if (ctx->err)
 507                 UCI_THROW(ctx, ctx->err);
 508
 509         return 0;
 510 }
 511
 512