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/* vi: set ts=4:
*
* mke2fs.c - Create an ext2 filesystem image.
*
* Copyright 2006 Rob Landley <rob@landley.net>
*/
#include "toys.h"
// 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
// 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;
off_t length;
// Handle command line arguments.
if (toys.optargs[1]) {
sscanf(toys.optargs[1], "%u", &(sb->inodes_count));
temp = O_RDWR|O_CREAT;
} else temp = O_RDWR;
// Check if filesystem is mounted
// For mke?fs, open file. For gene?fs, create file.
length = fdlength(toy.mke2fs.fsfd = xcreate(*toys.optargs, temp, 0777));
if (toy.mke2fs.blocksize && toy.mke2fs.blocksize!=1024
&& toy.mke2fs.blocksize!=2048 && toy.mke2fs.blocksize!=4096)
error_exit("bad blocksize");
// Determine block size. If unspecified, use simple heuristic.
if (toy.mke2fs.blocksize)
sb->log_block_size = (length && length < 1<<24) ? 1024 : 4096;
else sb->log_block_size = toy.mke2fs.blocksize;
if (!sb->inodes_count) sb->inodes_count = length/toy.mke2fs.blocksize;
// 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;
// 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)) perror_exit("lseek");
//{ toy.mke2fs.noseek=1; xwrite(toy.mke2fs.fsfd, sb, 1024); }
// Write superblock to disk.
xwrite(toy.mke2fs.fsfd, sb, 3072); // 4096-1024
return 0;
}
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