/* vi: set ts=4: * * mke2fs.c - Create an ext2 filesystem image. * * Copyright 2006 Rob Landley */ #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; }