misc/e2image.c

   1 /*
   2  * e2image.c --- Program which writes an image file backing up
   3  * critical metadata for the filesystem.
   4  *
   5  * Copyright 2000, 2001 by Theodore Ts'o.
   6  *
   7  * %Begin-Header%
   8  * This file may be redistributed under the terms of the GNU Public
   9  * License.
  10  * %End-Header%
  11  */
  12
  13 #define _LARGEFILE_SOURCE
  14 #define _LARGEFILE64_SOURCE
  15
  16 #include <fcntl.h>
  17 #include <grp.h>
  18 #ifdef HAVE_GETOPT_H
  19 #include <getopt.h>
  20 #else
  21 extern char *optarg;
  22 extern int optind;
  23 #endif
  24 #include <pwd.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <time.h>
  29 #include <unistd.h>
  30 #include <fcntl.h>
  31 #include <errno.h>
  32 #include <sys/stat.h>
  33 #include <sys/types.h>
  34
  35 #include "ext2fs/ext2_fs.h"
  36 #include "ext2fs/ext2fs.h"
  37 #include "et/com_err.h"
  38 #include "uuid/uuid.h"
  39 #include "e2p/e2p.h"
  40 #include "ext2fs/e2image.h"
  41
  42 #include "../version.h"
  43 #include "nls-enable.h"
  44
  45 const char * program_name = "e2image";
  46 char * device_name = NULL;
  47
  48 static void usage(void)
  49 {
  50         fprintf(stderr, _("Usage: %s [-r] device file\n"), program_name);
  51         exit (1);
  52 }
  53
  54 static void write_header(int fd, struct ext2_image_hdr *hdr, int blocksize)
  55 {
  56         char *header_buf;
  57         int actual;
  58
  59         header_buf = malloc(blocksize);
  60         if (!header_buf) {
  61                 fprintf(stderr, _("Couldn't allocate header buffer\n"));
  62                 exit(1);
  63         }
  64
  65         if (lseek(fd, 0, SEEK_SET) < 0) {
  66                 perror("lseek while writing header");
  67                 exit(1);
  68         }
  69         memset(header_buf, 0, blocksize);
  70
  71         if (hdr)
  72                 memcpy(header_buf, hdr, sizeof(struct ext2_image_hdr));
  73
  74         actual = write(fd, header_buf, blocksize);
  75         if (actual < 0) {
  76                 perror("write header");
  77                 exit(1);
  78         }
  79         if (actual != blocksize) {
  80                 fprintf(stderr, _("short write (only %d bytes) for"
  81                                   "writing image header"), actual);
  82                 exit(1);
  83         }
  84         free(header_buf);
  85 }
  86
  87 static void write_image_file(ext2_filsys fs, int fd)
  88 {
  89         struct ext2_image_hdr   hdr;
  90         struct stat             st;
  91         errcode_t               retval;
  92
  93         write_header(fd, NULL, fs->blocksize);
  94         memset(&hdr, 0, sizeof(struct ext2_image_hdr));
  95
  96         hdr.offset_super = lseek(fd, 0, SEEK_CUR);
  97         retval = ext2fs_image_super_write(fs, fd, 0);
  98         if (retval) {
  99                 com_err(program_name, retval, _("while writing superblock"));
 100                 exit(1);
 101         }
 102
 103         hdr.offset_inode = lseek(fd, 0, SEEK_CUR);
 104         retval = ext2fs_image_inode_write(fs, fd,
 105                                   (fd != 1) ? IMAGER_FLAG_SPARSEWRITE : 0);
 106         if (retval) {
 107                 com_err(program_name, retval, _("while writing inode table"));
 108                 exit(1);
 109         }
 110
 111         hdr.offset_blockmap = lseek(fd, 0, SEEK_CUR);
 112         retval = ext2fs_image_bitmap_write(fs, fd, 0);
 113         if (retval) {
 114                 com_err(program_name, retval, _("while writing block bitmap"));
 115                 exit(1);
 116         }
 117
 118         hdr.offset_inodemap = lseek(fd, 0, SEEK_CUR);
 119         retval = ext2fs_image_bitmap_write(fs, fd, IMAGER_FLAG_INODEMAP);
 120         if (retval) {
 121                 com_err(program_name, retval, _("while writing inode bitmap"));
 122                 exit(1);
 123         }
 124
 125         hdr.magic_number = EXT2_ET_MAGIC_E2IMAGE;
 126         strcpy(hdr.magic_descriptor, "Ext2 Image 1.0");
 127         gethostname(hdr.fs_hostname, sizeof(hdr.fs_hostname));
 128         strncat(hdr.fs_device_name, device_name, sizeof(hdr.fs_device_name));
 129         hdr.fs_device_name[sizeof(hdr.fs_device_name) - 1] = 0;
 130         hdr.fs_blocksize = fs->blocksize;
 131
 132         if (stat(device_name, &st) == 0)
 133                 hdr.fs_device = st.st_rdev;
 134
 135         if (fstat(fd, &st) == 0) {
 136                 hdr.image_device = st.st_dev;
 137                 hdr.image_inode = st.st_ino;
 138         }
 139         memcpy(hdr.fs_uuid, fs->super->s_uuid, sizeof(hdr.fs_uuid));
 140
 141         hdr.image_time = time(0);
 142         write_header(fd, &hdr, fs->blocksize);
 143 }
 144
 145 /*
 146  * These set of functions are used to write a RAW image file.
 147  */
 148 ext2fs_block_bitmap meta_block_map;
 149
 150 struct process_block_struct {
 151         ext2_ino_t      ino;
 152 };
 153
 154 /*
 155  * These subroutines short circuits ext2fs_get_blocks and
 156  * ext2fs_check_directory; we use them since we already have the inode
 157  * structure, so there's no point in letting the ext2fs library read
 158  * the inode again.
 159  */
 160 static ino_t stashed_ino = 0;
 161 static struct ext2_inode *stashed_inode;
 162
 163 static errcode_t meta_get_blocks(ext2_filsys fs, ext2_ino_t ino,
 164                                   blk_t *blocks)
 165 {
 166         int     i;
 167
 168         if ((ino != stashed_ino) || !stashed_inode)
 169                 return EXT2_ET_CALLBACK_NOTHANDLED;
 170
 171         for (i=0; i < EXT2_N_BLOCKS; i++)
 172                 blocks[i] = stashed_inode->i_block[i];
 173         return 0;
 174 }
 175
 176 static errcode_t meta_check_directory(ext2_filsys fs, ext2_ino_t ino)
 177 {
 178         if ((ino != stashed_ino) || !stashed_inode)
 179                 return EXT2_ET_CALLBACK_NOTHANDLED;
 180
 181         if (!LINUX_S_ISDIR(stashed_inode->i_mode))
 182                 return EXT2_ET_NO_DIRECTORY;
 183         return 0;
 184 }
 185
 186 static errcode_t meta_read_inode(ext2_filsys fs, ext2_ino_t ino,
 187                                  struct ext2_inode *inode)
 188 {
 189         if ((ino != stashed_ino) || !stashed_inode)
 190                 return EXT2_ET_CALLBACK_NOTHANDLED;
 191         *inode = *stashed_inode;
 192         return 0;
 193 }
 194
 195 static void use_inode_shortcuts(ext2_filsys fs, int bool)
 196 {
 197         if (bool) {
 198                 fs->get_blocks = meta_get_blocks;
 199                 fs->check_directory = meta_check_directory;
 200                 fs->read_inode = meta_read_inode;
 201                 stashed_ino = 0;
 202         } else {
 203                 fs->get_blocks = 0;
 204                 fs->check_directory = 0;
 205                 fs->read_inode = 0;
 206         }
 207 }
 208
 209 static int process_dir_block(ext2_filsys fs, blk_t *block_nr,
 210                              e2_blkcnt_t blockcnt, blk_t ref_block,
 211                              int ref_offset, void *priv_data)
 212 {
 213         ext2fs_mark_block_bitmap(meta_block_map, *block_nr);
 214         return 0;
 215 }
 216
 217 static int process_file_block(ext2_filsys fs, blk_t *block_nr,
 218                              e2_blkcnt_t blockcnt, blk_t ref_block,
 219                              int ref_offset, void *priv_data)
 220 {
 221         if (blockcnt < 0) {
 222                 ext2fs_mark_block_bitmap(meta_block_map, *block_nr);
 223         }
 224         return 0;
 225 }
 226
 227 static void mark_table_blocks(ext2_filsys fs)
 228 {
 229         blk_t   block, b;
 230         int     i,j;
 231
 232         block = fs->super->s_first_data_block;
 233         /*
 234          * Mark primary superblock
 235          */
 236         ext2fs_mark_block_bitmap(meta_block_map, block);
 237
 238         /*
 239          * Mark the primary superblock descriptors
 240          */
 241         for (j = 0; j < fs->desc_blocks; j++) {
 242                 ext2fs_mark_block_bitmap(meta_block_map,
 243                                          block + j + 1);
 244         }
 245
 246         for (i = 0; i < fs->group_desc_count; i++) {
 247                 /*
 248                  * Mark the blocks used for the inode table
 249                  */
 250                 if (fs->group_desc[i].bg_inode_table) {
 251                         for (j = 0, b = fs->group_desc[i].bg_inode_table;
 252                              j < fs->inode_blocks_per_group;
 253                              j++, b++)
 254                                 ext2fs_mark_block_bitmap(meta_block_map, b);
 255                 }
 256
 257                 /*
 258                  * Mark block used for the block bitmap
 259                  */
 260                 if (fs->group_desc[i].bg_block_bitmap) {
 261                         ext2fs_mark_block_bitmap(meta_block_map,
 262                                      fs->group_desc[i].bg_block_bitmap);
 263                 }
 264
 265                 /*
 266                  * Mark block used for the inode bitmap
 267                  */
 268                 if (fs->group_desc[i].bg_inode_bitmap) {
 269                         ext2fs_mark_block_bitmap(meta_block_map,
 270                                  fs->group_desc[i].bg_inode_bitmap);
 271                 }
 272                 block += fs->super->s_blocks_per_group;
 273         }
 274 }
 275
 276 /*
 277  * This function returns 1 if the specified block is all zeros
 278  */
 279 static int check_zero_block(char *buf, int blocksize)
 280 {
 281         char    *cp = buf;
 282         int     left = blocksize;
 283
 284         while (left > 0) {
 285                 if (*cp++)
 286                         return 0;
 287                 left--;
 288         }
 289         return 1;
 290 }
 291
 292 static void write_block(int fd, char *buf, int sparse_offset,
 293                         int blocksize, blk_t block)
 294 {
 295         int             count;
 296         errcode_t       err;
 297
 298         if (sparse_offset) {
 299 #ifdef HAVE_LSEEK64
 300                 if (lseek64(fd, sparse_offset, SEEK_CUR) < 0)
 301                         perror("lseek");
 302 #else
 303                 if (lseek(fd, sparse_offset, SEEK_CUR) < 0)
 304                         perror("lseek");
 305 #endif
 306         }
 307         if (blocksize) {
 308                 count = write(fd, buf, blocksize);
 309                 if (count != blocksize) {
 310                         if (count == -1)
 311                                 err = errno;
 312                         else
 313                                 err = 0;
 314                         com_err(program_name, err, "error writing block %d",
 315                                 block);
 316                 }
 317         }
 318 }
 319
 320 static void output_meta_data_blocks(ext2_filsys fs, int fd)
 321 {
 322         errcode_t       retval;
 323         blk_t           blk;
 324         char            buf[8192], zero_buf[8192];
 325         int             sparse = 0;
 326
 327         memset(zero_buf, 0, sizeof(zero_buf));
 328         for (blk = 0; blk < fs->super->s_blocks_count; blk++) {
 329                 if ((blk >= fs->super->s_first_data_block) &&
 330                     ext2fs_test_block_bitmap(meta_block_map, blk)) {
 331                         retval = io_channel_read_blk(fs->io, blk, 1, buf);
 332                         if (retval) {
 333                                 com_err(program_name, retval,
 334                                         "error reading block %d", blk);
 335                         }
 336                         if ((fd != 1) && check_zero_block(buf, fs->blocksize))
 337                                 goto sparse_write;
 338                         write_block(fd, buf, sparse, fs->blocksize, blk);
 339                         sparse = 0;
 340                 } else {
 341                 sparse_write:
 342                         if (fd == 1) {
 343                                 write_block(fd, zero_buf, 0,
 344                                             fs->blocksize, blk);
 345                                 continue;
 346                         }
 347                         sparse += fs->blocksize;
 348                         if (sparse >= 1024*1024) {
 349                                 write_block(fd, 0, sparse, 0, 0);
 350                                 sparse = 0;
 351                         }
 352                 }
 353         }
 354         write_block(fd, zero_buf, sparse, 1, -1);
 355 }
 356
 357 static void write_raw_image_file(ext2_filsys fs, int fd)
 358 {
 359         struct process_block_struct     pb;
 360         struct ext2_inode               inode;
 361         ext2_inode_scan                 scan;
 362         ext2_ino_t                      ino;
 363         errcode_t                       retval;
 364         char *                          block_buf;
 365
 366         retval = ext2fs_allocate_block_bitmap(fs, "in-use block map",
 367                                               &meta_block_map);
 368         if (retval) {
 369                 com_err(program_name, retval, "while allocating block bitmap");
 370                 exit(1);
 371         }
 372
 373         mark_table_blocks(fs);
 374
 375         retval = ext2fs_open_inode_scan(fs, 0, &scan);
 376         if (retval) {
 377                 com_err(program_name, retval, _("while opening inode scan"));
 378                 exit(1);
 379         }
 380
 381         block_buf = malloc(fs->blocksize * 3);
 382         if (!block_buf) {
 383                 com_err(program_name, 0, "Can't allocate block buffer");
 384                 exit(1);
 385         }
 386
 387         use_inode_shortcuts(fs, 1);
 388         stashed_inode = &inode;
 389         while (1) {
 390                 retval = ext2fs_get_next_inode(scan, &ino, &inode);
 391                 if (retval) {
 392                         com_err(program_name, retval,
 393                                 _("while getting next inode"));
 394                         exit(1);
 395                 }
 396                 if (ino == 0)
 397                         break;
 398                 if (!inode.i_links_count ||
 399                     !ext2fs_inode_has_valid_blocks(&inode))
 400                         continue;
 401
 402                 stashed_ino = ino;
 403                 if (LINUX_S_ISDIR(inode.i_mode) ||
 404                     ino == fs->super->s_journal_inum) {
 405                         retval = ext2fs_block_iterate2(fs, ino, 0,
 406                                        block_buf, process_dir_block, &pb);
 407                         if (retval) {
 408                                 com_err(program_name, retval,
 409                                         "while iterating over inode %d",
 410                                         ino);
 411                                 exit(1);
 412                         }
 413                 } else {
 414                         if (inode.i_block[EXT2_IND_BLOCK] ||
 415                             inode.i_block[EXT2_DIND_BLOCK] ||
 416                             inode.i_block[EXT2_TIND_BLOCK]) {
 417                                 retval = ext2fs_block_iterate2(fs,
 418                                        ino, 0, block_buf,
 419                                        process_file_block, &pb);
 420                                 if (retval) {
 421                                         com_err(program_name, retval,
 422                                         "while iterating over %d", ino);
 423                                         exit(1);
 424                                 }
 425                         }
 426                         if (inode.i_file_acl) {
 427                                 ext2fs_mark_block_bitmap(meta_block_map,
 428                                                          inode.i_file_acl);
 429                         }
 430                 }
 431         }
 432         use_inode_shortcuts(fs, 0);
 433         output_meta_data_blocks(fs, fd);
 434 }
 435
 436 int main (int argc, char ** argv)
 437 {
 438         int c;
 439         errcode_t retval;
 440         ext2_filsys fs;
 441         char *outfn;
 442         int open_flag = 0;
 443         int raw_flag = 0;
 444         int fd = 0;
 445
 446 #ifdef ENABLE_NLS
 447         setlocale(LC_MESSAGES, "");
 448         bindtextdomain(NLS_CAT_NAME, LOCALEDIR);
 449         textdomain(NLS_CAT_NAME);
 450 #endif
 451         fprintf (stderr, "e2image %s (%s)\n", E2FSPROGS_VERSION,
 452                  E2FSPROGS_DATE);
 453         if (argc && *argv)
 454                 program_name = *argv;
 455         initialize_ext2_error_table();
 456         while ((c = getopt (argc, argv, "r")) != EOF)
 457                 switch (c) {
 458                 case 'r':
 459                         raw_flag++;
 460                         break;
 461                 default:
 462                         usage();
 463                 }
 464         if (optind != argc - 2 )
 465                 usage();
 466         device_name = argv[optind];
 467         outfn = argv[optind+1];
 468         retval = ext2fs_open (device_name, open_flag, 0, 0,
 469                               unix_io_manager, &fs);
 470         if (retval) {
 471                 com_err (program_name, retval, _("while trying to open %s"),
 472                          device_name);
 473                 printf(_("Couldn't find valid filesystem superblock.\n"));
 474                 exit(1);
 475         }
 476
 477         if (strcmp(outfn, "-") == 0)
 478                 fd = 1;
 479         else {
 480 #ifdef HAVE_OPEN64
 481                 fd = open64(outfn, O_CREAT|O_TRUNC|O_WRONLY, 0600);
 482 #else
 483                 fd = open(outfn, O_CREAT|O_TRUNC|O_WRONLY, 0600);
 484 #endif
 485                 if (fd < 0) {
 486                         com_err(program_name, errno,
 487                                 _("while trying to open %s"), argv[optind+1]);
 488                         exit(1);
 489                 }
 490         }
 491
 492         if (raw_flag)
 493                 write_raw_image_file(fs, fd);
 494         else
 495                 write_image_file(fs, fd);
 496
 497         ext2fs_close (fs);
 498         exit (0);
 499 }