ext4_utils/ext2simg.c

   1 /*
   2  * Copyright (C) 2010 The Android Open Source Project
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include "ext4_utils.h"
  18 #include "make_ext4fs.h"
  19 #include "output_file.h"
  20 #include "backed_block.h"
  21 #include "allocate.h"
  22
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <sys/types.h>
  26 #include <sys/mman.h>
  27 #include <fcntl.h>
  28 #include <libgen.h>
  29 #include <unistd.h>
  30
  31 extern struct fs_info info;
  32
  33 static int verbose = 0;
  34
  35 static void usage(char *path)
  36 {
  37         fprintf(stderr, "%s [ options ] <image or block device> <output image>\n", path);
  38         fprintf(stderr, "\n");
  39         fprintf(stderr, "  -c include CRC block\n");
  40         fprintf(stderr, "  -v verbose output\n");
  41         fprintf(stderr, "  -z gzip output\n");
  42         fprintf(stderr, "  -S don't use sparse output format\n");
  43 }
  44
  45 static int read_ext(int fd)
  46 {
  47         off64_t ret;
  48         struct ext4_super_block sb;
  49         unsigned int i;
  50
  51         ret = lseek64(fd, 1024, SEEK_SET);
  52         if (ret < 0)
  53                 critical_error_errno("failed to seek to superblock");
  54
  55         ret = read(fd, &sb, sizeof(sb));
  56         if (ret < 0)
  57                 critical_error_errno("failed to read superblock");
  58         if (ret != sizeof(sb))
  59                 critical_error("failed to read all of superblock");
  60
  61         ext4_parse_sb(&sb);
  62
  63         ret = lseek64(fd, info.len, SEEK_SET);
  64         if (ret < 0)
  65                 critical_error_errno("failed to seek to end of input image");
  66
  67         ret = lseek64(fd, info.block_size * (aux_info.first_data_block + 1), SEEK_SET);
  68         if (ret < 0)
  69                 critical_error_errno("failed to seek to block group descriptors");
  70
  71         ret = read(fd, aux_info.bg_desc, info.block_size * aux_info.bg_desc_blocks);
  72         if (ret < 0)
  73                 critical_error_errno("failed to read block group descriptors");
  74         if (ret != (int)info.block_size * (int)aux_info.bg_desc_blocks)
  75                 critical_error("failed to read all of block group descriptors");
  76
  77         if (verbose) {
  78                 printf("Found filesystem with parameters:\n");
  79                 printf("    Size: %llu\n", info.len);
  80                 printf("    Block size: %d\n", info.block_size);
  81                 printf("    Blocks per group: %d\n", info.blocks_per_group);
  82                 printf("    Inodes per group: %d\n", info.inodes_per_group);
  83                 printf("    Inode size: %d\n", info.inode_size);
  84                 printf("    Label: %s\n", info.label);
  85                 printf("    Blocks: %llu\n", aux_info.len_blocks);
  86                 printf("    Block groups: %d\n", aux_info.groups);
  87                 printf("    Reserved block group size: %d\n", info.bg_desc_reserve_blocks);
  88                 printf("    Used %d/%d inodes and %d/%d blocks\n",
  89                                 aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
  90                                 aux_info.sb->s_inodes_count,
  91                                 aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
  92                                 aux_info.sb->s_blocks_count_lo);
  93         }
  94
  95         return 0;
  96 }
  97
  98 static int bitmap_get_bit(u8 *bitmap, u32 bit)
  99 {
 100         if (bitmap[bit / 8] & 1 << (bit % 8))
 101                 return 1;
 102
 103         return 0;
 104 }
 105
 106 static int build_sparse_ext(int fd, const char *filename)
 107 {
 108         unsigned int i;
 109         unsigned int block;
 110         int start_contiguous_block;
 111         u8 *block_bitmap;
 112         off64_t ret;
 113
 114         block_bitmap = malloc(info.block_size);
 115         if (!block_bitmap)
 116                 critical_error("failed to allocate block bitmap");
 117
 118         if (aux_info.first_data_block > 0)
 119                 queue_data_file(filename, 0,
 120                                 info.block_size * aux_info.first_data_block, 0);
 121
 122         for (i = 0; i < aux_info.groups; i++) {
 123                 u32 first_block = aux_info.first_data_block + i * info.blocks_per_group;
 124                 u32 last_block = min(info.blocks_per_group, aux_info.len_blocks - first_block);
 125
 126                 ret = lseek64(fd, (u64)info.block_size * aux_info.bg_desc[i].bg_block_bitmap,
 127                                 SEEK_SET);
 128                 if (ret < 0)
 129                         critical_error_errno("failed to seek to block group bitmap %d", i);
 130
 131                 ret = read(fd, block_bitmap, info.block_size);
 132                 if (ret < 0)
 133                         critical_error_errno("failed to read block group bitmap %d", i);
 134                 if (ret != (int)info.block_size)
 135                         critical_error("failed to read all of block group bitmap %d", i);
 136
 137                 start_contiguous_block = -1;
 138                 for (block = 0; block < last_block; block++) {
 139                         if (start_contiguous_block >= 0) {
 140                                 if (!bitmap_get_bit(block_bitmap, block)) {
 141                                         u32 start_block = first_block + start_contiguous_block;
 142                                         u32 len_blocks = block - start_contiguous_block;
 143
 144                                         queue_data_file(filename, (u64)info.block_size * start_block,
 145                                                         info.block_size * len_blocks, start_block);
 146                                         start_contiguous_block = -1;
 147                                 }
 148                         } else {
 149                                 if (bitmap_get_bit(block_bitmap, block))
 150                                         start_contiguous_block = block;
 151                         }
 152                 }
 153
 154                 if (start_contiguous_block >= 0) {
 155                         u32 start_block = first_block + start_contiguous_block;
 156                         u32 len_blocks = last_block - start_contiguous_block;
 157                         queue_data_file(filename, (u64)info.block_size * start_block,
 158                                         info.block_size * len_blocks, start_block);
 159                 }
 160         }
 161
 162         return 0;
 163 }
 164
 165 int main(int argc, char **argv)
 166 {
 167         int opt;
 168         const char *in = NULL;
 169         const char *out = NULL;
 170         int gzip = 0;
 171         int sparse = 1;
 172         int fd;
 173         int crc = 0;
 174
 175         while ((opt = getopt(argc, argv, "cvzS")) != -1) {
 176                 switch (opt) {
 177                 case 'c':
 178                         crc = 1;
 179                         break;
 180                 case 'v':
 181                         verbose = 1;
 182                         break;
 183                 case 'z':
 184                         gzip = 1;
 185                         break;
 186                 case 'S':
 187                         sparse = 0;
 188                         break;
 189                 }
 190         }
 191
 192         if (optind >= argc) {
 193                 fprintf(stderr, "Expected image or block device after options\n");
 194                 usage(argv[0]);
 195                 exit(EXIT_FAILURE);
 196         }
 197
 198         in = argv[optind++];
 199
 200         if (optind >= argc) {
 201                 fprintf(stderr, "Expected output image after input image\n");
 202                 usage(argv[0]);
 203                 exit(EXIT_FAILURE);
 204         }
 205
 206         out = argv[optind++];
 207
 208         if (optind < argc) {
 209                 fprintf(stderr, "Unexpected argument: %s\n", argv[optind]);
 210                 usage(argv[0]);
 211                 exit(EXIT_FAILURE);
 212         }
 213
 214         fd = open(in, O_RDONLY);
 215
 216         if (fd < 0)
 217                 critical_error_errno("failed to open input image");
 218
 219         read_ext(fd);
 220
 221         build_sparse_ext(fd, in);
 222
 223         close(fd);
 224
 225         write_ext4_image(out, gzip, sparse, crc);
 226
 227         return 0;
 228 }