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Diffstat (limited to 'toys/mke2fs.c')
| -rw-r--r-- | toys/mke2fs.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/toys/mke2fs.c b/toys/mke2fs.c new file mode 100644 index 00000000..a586a906 --- /dev/null +++ b/toys/mke2fs.c @@ -0,0 +1,241 @@ +/* vi: set ts=4: + * + * mke2fs.c - Create an ext2 filesystem image. + * + * Copyright 2006 Rob Landley <rob@landley.net> + */ + +#include "toys.h" + +// Stuff defined in linux/ext2_fs.h + +#define EXT2_SUPER_MAGIC 0xEF53 + +struct ext2_inode { + uint16_t mode; // File mode + uint16_t uid; // Low 16 bits of Owner Uid + uint32_t size; // Size in bytes + uint32_t atime; // Access time + uint32_t ctime; // Creation time + uint32_t mtime; // Modification time + uint32_t dtime; // Deletion Time + uint16_t gid; // Low 16 bits of Group Id + uint16_t links_count; // Links count + uint32_t blocks; // Blocks count + uint32_t flags; // File flags + uint32_t reserved1; + uint32_t block[15]; // Pointers to blocks + uint32_t generation; // File version (for NFS) + uint32_t file_acl; // File ACL + uint32_t dir_acl; // Directory ACL + uint32_t faddr; // Fragment address + uint8_t frag; // Fragment number + uint8_t fsize; // Fragment size + uint16_t pad1; + uint16_t uid_high; // High bits of uid + uint16_t gid_high; // High bits of gid + uint32_t reserved2; +}; + +struct ext2_super_block { + uint32_t inodes_count; // Inodes count + uint32_t blocks_count; // Blocks count + uint32_t r_blocks_count; // Reserved blocks count + uint32_t free_blocks_count; // Free blocks count + uint32_t free_inodes_count; // Free inodes count + uint32_t first_data_block; // First Data Block + uint32_t log_block_size; // Block size + uint32_t log_frag_size; // Fragment size + uint32_t blocks_per_group; // # Blocks per group + uint32_t frags_per_group; // # Fragments per group + uint32_t inodes_per_group; // # Inodes per group + uint32_t mtime; // Mount time + uint32_t wtime; // Write time + uint16_t mnt_count; // Mount count + uint16_t max_mnt_count; // Maximal mount count + uint16_t magic; // Magic signature + uint16_t state; // File system state + uint16_t errors; // Behaviour when detecting errors + uint16_t minor_rev_level; // minor revision level + uint32_t lastcheck; // time of last check + uint32_t checkinterval; // max. time between checks + uint32_t creator_os; // OS + uint32_t rev_level; // Revision level + uint16_t def_resuid; // Default uid for reserved blocks + uint16_t def_resgid; // Default gid for reserved blocks + uint32_t first_ino; // First non-reserved inode + uint16_t inode_size; // size of inode structure + uint16_t block_group_nr; // block group # of this superblock + uint32_t feature_compat; // compatible feature set + uint32_t feature_incompat; // incompatible feature set + uint32_t feature_ro_compat; // readonly-compatible feature set + char uuid[16]; // 128-bit uuid for volume + char volume_name[16]; // volume name + char last_mounted[64]; // directory where last mounted + uint32_t alg_usage_bitmap; // For compression + // For EXT2_COMPAT_PREALLOC + uint8_t prealloc_blocks; // Nr of blocks to try to preallocate + uint8_t prealloc_dir_blocks; //Nr to preallocate for dirs + uint16_t padding1; + // For EXT3_FEATURE_COMPAT_HAS_JOURNAL + uint8_t journal_uuid[16]; // uuid of journal superblock + uint32_t journal_inum; // inode number of journal file + uint32_t journal_dev; // device number of journal file + uint32_t last_orphan; // start of list of inodes to delete + uint32_t hash_seed[4]; // HTREE hash seed + uint8_t def_hash_version; // Default hash version to use + uint8_t padding2[3]; + uint32_t default_mount_opts; + uint32_t first_meta_bg; // First metablock block group + uint32_t reserved[190]; // Padding to the end of the block +}; + +#define EXT2_FEATURE_COMPAT_DIR_PREALLOC 0x0001 +#define EXT2_FEATURE_COMPAT_IMAGIC_INODES 0x0002 +#define EXT3_FEATURE_COMPAT_HAS_JOURNAL 0x0004 +#define EXT2_FEATURE_COMPAT_EXT_ATTR 0x0008 +#define EXT2_FEATURE_COMPAT_RESIZE_INO 0x0010 +#define EXT2_FEATURE_COMPAT_DIR_INDEX 0x0020 + +#define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001 +#define EXT2_FEATURE_RO_COMPAT_LARGE_FILE 0x0002 +#define EXT2_FEATURE_RO_COMPAT_BTREE_DIR 0x0004 + +#define EXT2_FEATURE_INCOMPAT_COMPRESSION 0x0001 +#define EXT2_FEATURE_INCOMPAT_FILETYPE 0x0002 +#define EXT3_FEATURE_INCOMPAT_RECOVER 0x0004 +#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008 +#define EXT2_FEATURE_INCOMPAT_META_BG 0x0010 + +#define EXT2_NAME_LEN 255 + +struct ext2_dir_entry_2 { + uint32_t inode; // Inode number + uint16_t rec_len; // Directory entry length + uint8_t name_len; // Name length + uint8_t file_type; + char name[255]; // File name +}; + +// Ext2 directory file types. Only the low 3 bits are used. The +// other bits are reserved for now. + +enum { + EXT2_FT_UNKNOWN, + EXT2_FT_REG_FILE, + EXT2_FT_DIR, + EXT2_FT_CHRDEV, + EXT2_FT_BLKDEV, + EXT2_FT_FIFO, + EXT2_FT_SOCK, + EXT2_FT_SYMLINK, + EXT2_FT_MAX +}; + + + // b - block size (1024, 2048, 4096) + // F - force (run on mounted device or non-block device) + // i - bytes per inode + // N - number of inodes + // m - reserved blocks percentage + // n - Don't write + // q - quiet + + // L - volume label + // M - last mounted path + // o - creator os + + // j - create journal + // J - journal options (size=1024-102400 blocks,device=) + // device=/dev/blah or LABEL=label UUID=uuid + + // E - extended options (stride=stripe-size blocks) + // O - none,dir_index,filetype,has_journal,journal_dev,sparse_super + + +// This is what's in a UUID according to the spec at +// http://www.opengroup.org/onlinepubs/9629399/apdxa.htm + +//struct uuid { +// uint32_t time_low; +// uint16_t time_mid; +// uint16_t time_hi_and_version; +// uint8_t clock_seq_hi_and_reserved; +// uint8_t clock_seq_low; +// uint8_t node[6]; +//}; + + +// According to http://www.opengroup.org/onlinepubs/9629399/apdxa.htm +// we should generate a uuid structure by reading a clock with 100 nanosecond +// precision, normalizing it to the start of the gregorian calendar in 1582, +// and looking up our eth0 mac address. +// +// On the other hand, we have 128 bits to come up with a unique identifier, of +// which 6 have a defined value. /dev/urandom it is. + +void create_uuid(char *uuid) +{ + // Read 128 random bytes + int fd = xopen("/dev/urandom", O_RDONLY); + xreadall(fd, uuid, 16); + close(fd); + + // Claim to be a DCE format UUID. + uuid[6] = (uuid[6] & 0x0F) | 0x40; + uuid[8] = (uuid[8] & 0x3F) | 0x80; + + // rfc2518 section 6.4.1 suggests if we're not using a macaddr, we should + // set bit 1 of the node ID, which is the mac multicast bit. This means we + // should never collide with anybody actually using a macaddr. + uuid[11] = uuid[11] | 128; +} + +int mke2fs_main(void) +{ + struct ext2_super_block *sb = xzalloc(sizeof(struct ext2_super_block)); + int temp; + + // Handle command line arguments. + + if (!*toys.optargs || (!CFG_MKE2FS_GEN && toys.optargs[1])) usage_exit(); + if (CFG_MKE2FS_GEN && toys.optargs[1]) { + temp = O_RDWR|O_CREAT; + xaccess(toys.optargs[1], R_OK); + } else temp = O_RDWR; + if (toy.mke2fs.blocksize!=1024 && toy.mke2fs.blocksize!=2048 + && toy.mke2fs.blocksize!=4096) error_exit("bad blocksize"); + + // For mke?fs, open file. For gene?fs, create file. + toy.mke2fs.fsfd = xcreate(*toys.optargs, temp, 0777); + + // We don't autodetect block size from external journaling devices, instead + // we write our block size to that journaling device. (If they want a + // specific block size, they have the -b option.) + +// What's the deal with fs_type? +// line 1059 + + // We skip the first 1k (to avoid the boot sector, if any). Use this to + // figure out if this file is seekable. + if(-1 == lseek(toy.mke2fs.fsfd, 1024, SEEK_SET)) { + toy.mke2fs.noseek=1; + xwrite(toy.mke2fs.fsfd, sb, 1024); + } + + // Fill out superblock structure + + sb->rev_level = SWAP_LE32(1); + sb->feature_incompat = SWAP_LE32(EXT2_FEATURE_INCOMPAT_FILETYPE); + sb->feature_ro_compat = SWAP_LE32(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER); + + // If we're called as mke3fs or mkfs.ext3, do a journal. + + if (strchr(toys.which->name,'3')) + sb->feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL; + + // Write superblock to disk. + xwrite(toy.mke2fs.fsfd, sb, 3072); // 4096-1024 + + return 0; +} |