e2fsprogs/ext2fs/rw_bitmaps.c - codeaurora/busybox - Gitiles

 /*
  * rw_bitmaps.c --- routines to read and write the  inode and block bitmaps.
  *
  * Copyright (C) 1993, 1994, 1994, 1996 Theodore Ts'o.
  *
  * %Begin-Header%
  * This file may be redistributed under the terms of the GNU Public
  * License.
  * %End-Header%
  */

 #include <stdio.h>
 #include <string.h>
 #if HAVE_UNISTD_H
 #include <unistd.h>
 #endif
 #include <fcntl.h>
 #include <time.h>
 #ifdef HAVE_SYS_STAT_H
 #include <sys/stat.h>
 #endif
 #ifdef HAVE_SYS_TYPES_H
 #include <sys/types.h>
 #endif

 #include "ext2_fs.h"
 #include "ext2fs.h"
 #include "e2image.h"

 #if defined(__powerpc__) && defined(EXT2FS_ENABLE_SWAPFS)
 /*
  * On the PowerPC, the big-endian variant of the ext2 filesystem
  * has its bitmaps stored as 32-bit words with bit 0 as the LSB
  * of each word.  Thus a bitmap with only bit 0 set would be, as
  * a string of bytes, 00 00 00 01 00 ...
  * To cope with this, we byte-reverse each word of a bitmap if
  * we have a big-endian filesystem, that is, if we are *not*
  * byte-swapping other word-sized numbers.
  */
 #define EXT2_BIG_ENDIAN_BITMAPS
 #endif

 #ifdef EXT2_BIG_ENDIAN_BITMAPS
 static void ext2fs_swap_bitmap(ext2_filsys fs, char *bitmap, int nbytes)
 {
 	__u32 *p = (__u32 *) bitmap;
 	int n;

 	for (n = nbytes / sizeof(__u32); n > 0; --n, ++p)
 		*p = ext2fs_swab32(*p);
 }
 #endif

 errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
 {
 	dgrp_t 		i;
 	size_t		nbytes;
 	errcode_t	retval;
 	char * inode_bitmap = fs->inode_map->bitmap;
 	char * bitmap_block = NULL;
 	blk_t		blk;

 	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

 	if (!(fs->flags & EXT2_FLAG_RW))
 		return EXT2_ET_RO_FILSYS;
 	if (!inode_bitmap)
 		return 0;
 	nbytes = (size_t) ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);

 	retval = ext2fs_get_mem(fs->blocksize, &bitmap_block);
 	if (retval)
 		return retval;
 	memset(bitmap_block, 0xff, fs->blocksize);
 	for (i = 0; i < fs->group_desc_count; i++) {
 		memcpy(bitmap_block, inode_bitmap, nbytes);
 		blk = fs->group_desc[i].bg_inode_bitmap;
 		if (blk) {
 #ifdef EXT2_BIG_ENDIAN_BITMAPS
 			if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 			      (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)))
 				ext2fs_swap_bitmap(fs, bitmap_block, nbytes);
 #endif
 			retval = io_channel_write_blk(fs->io, blk, 1,
 						      bitmap_block);
 			if (retval)
 				return EXT2_ET_INODE_BITMAP_WRITE;
 		}
 		inode_bitmap += nbytes;
 	}
 	fs->flags &= ~EXT2_FLAG_IB_DIRTY;
 	ext2fs_free_mem(&bitmap_block);
 	return 0;
 }

 errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
 {
 	dgrp_t 		i;
 	unsigned int	j;
 	int		nbytes;
 	unsigned int	nbits;
 	errcode_t	retval;
 	char * block_bitmap = fs->block_map->bitmap;
 	char * bitmap_block = NULL;
 	blk_t		blk;

 	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

 	if (!(fs->flags & EXT2_FLAG_RW))
 		return EXT2_ET_RO_FILSYS;
 	if (!block_bitmap)
 		return 0;
 	nbytes = EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
 	retval = ext2fs_get_mem(fs->blocksize, &bitmap_block);
 	if (retval)
 		return retval;
 	memset(bitmap_block, 0xff, fs->blocksize);
 	for (i = 0; i < fs->group_desc_count; i++) {
 		memcpy(bitmap_block, block_bitmap, nbytes);
 		if (i == fs->group_desc_count - 1) {
 			/* Force bitmap padding for the last group */
 			nbits = ((fs->super->s_blocks_count
 				  - fs->super->s_first_data_block)
 				 % EXT2_BLOCKS_PER_GROUP(fs->super));
 			if (nbits)
 				for (j = nbits; j < fs->blocksize * 8; j++)
 					ext2fs_set_bit(j, bitmap_block);
 		}
 		blk = fs->group_desc[i].bg_block_bitmap;
 		if (blk) {
 #ifdef EXT2_BIG_ENDIAN_BITMAPS
 			if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 			      (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)))
 				ext2fs_swap_bitmap(fs, bitmap_block, nbytes);
 #endif
 			retval = io_channel_write_blk(fs->io, blk, 1,
 						      bitmap_block);
 			if (retval)
 				return EXT2_ET_BLOCK_BITMAP_WRITE;
 		}
 		block_bitmap += nbytes;
 	}
 	fs->flags &= ~EXT2_FLAG_BB_DIRTY;
 	ext2fs_free_mem(&bitmap_block);
 	return 0;
 }

 static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
 {
 	dgrp_t i;
 	char *block_bitmap = 0, *inode_bitmap = 0;
 	char *buf;
 	errcode_t retval;
 	int block_nbytes = (int) EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
 	int inode_nbytes = (int) EXT2_INODES_PER_GROUP(fs->super) / 8;
 	blk_t	blk;

 	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

 	fs->write_bitmaps = ext2fs_write_bitmaps;

 	retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 	if (retval)
 		return retval;
 	if (do_block) {
 		if (fs->block_map)
 			ext2fs_free_block_bitmap(fs->block_map);
 		sprintf(buf, "block bitmap for %s", fs->device_name);
 		retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 		if (retval)
 			goto cleanup;
 		block_bitmap = fs->block_map->bitmap;
 	}
 	if (do_inode) {
 		if (fs->inode_map)
 			ext2fs_free_inode_bitmap(fs->inode_map);
 		sprintf(buf, "inode bitmap for %s", fs->device_name);
 		retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 		if (retval)
 			goto cleanup;
 		inode_bitmap = fs->inode_map->bitmap;
 	}
 	ext2fs_free_mem(&buf);

 	if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 		if (inode_bitmap) {
 			blk = (fs->image_header->offset_inodemap /
 			       fs->blocksize);
 			retval = io_channel_read_blk(fs->image_io, blk,
 			     -(inode_nbytes * fs->group_desc_count),
 			     inode_bitmap);
 			if (retval)
 				goto cleanup;
 		}
 		if (block_bitmap) {
 			blk = (fs->image_header->offset_blockmap /
 			       fs->blocksize);
 			retval = io_channel_read_blk(fs->image_io, blk,
 			     -(block_nbytes * fs->group_desc_count),
 			     block_bitmap);
 			if (retval)
 				goto cleanup;
 		}
 		return 0;
 	}

 	for (i = 0; i < fs->group_desc_count; i++) {
 		if (block_bitmap) {
 			blk = fs->group_desc[i].bg_block_bitmap;
 			if (blk) {
 				retval = io_channel_read_blk(fs->io, blk,
 					     -block_nbytes, block_bitmap);
 				if (retval) {
 					retval = EXT2_ET_BLOCK_BITMAP_READ;
 					goto cleanup;
 				}
 #ifdef EXT2_BIG_ENDIAN_BITMAPS
 				if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 				      (fs->flags & EXT2_FLAG_SWAP_BYTES_READ)))
 					ext2fs_swap_bitmap(fs, block_bitmap, block_nbytes);
 #endif
 			} else
 				memset(block_bitmap, 0, block_nbytes);
 			block_bitmap += block_nbytes;
 		}
 		if (inode_bitmap) {
 			blk = fs->group_desc[i].bg_inode_bitmap;
 			if (blk) {
 				retval = io_channel_read_blk(fs->io, blk,
 					     -inode_nbytes, inode_bitmap);
 				if (retval) {
 					retval = EXT2_ET_INODE_BITMAP_READ;
 					goto cleanup;
 				}
 #ifdef EXT2_BIG_ENDIAN_BITMAPS
 				if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 				      (fs->flags & EXT2_FLAG_SWAP_BYTES_READ)))
 					ext2fs_swap_bitmap(fs, inode_bitmap, inode_nbytes);
 #endif
 			} else
 				memset(inode_bitmap, 0, inode_nbytes);
 			inode_bitmap += inode_nbytes;
 		}
 	}
 	return 0;

 cleanup:
 	if (do_block) {
 		ext2fs_free_mem(&fs->block_map);
 		fs->block_map = 0;
 	}
 	if (do_inode) {
 		ext2fs_free_mem(&fs->inode_map);
 		fs->inode_map = 0;
 	}
 	if (buf)
 		ext2fs_free_mem(&buf);
 	return retval;
 }

 errcode_t ext2fs_read_inode_bitmap (ext2_filsys fs)
 {
 	return read_bitmaps(fs, 1, 0);
 }

 errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
 {
 	return read_bitmaps(fs, 0, 1);
 }

 errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
 {

 	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

 	if (fs->inode_map && fs->block_map)
 		return 0;

 	return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
 }

 errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
 {
 	errcode_t	retval;

 	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

 	if (fs->block_map && ext2fs_test_bb_dirty(fs)) {
 		retval = ext2fs_write_block_bitmap(fs);
 		if (retval)
 			return retval;
 	}
 	if (fs->inode_map && ext2fs_test_ib_dirty(fs)) {
 		retval = ext2fs_write_inode_bitmap(fs);
 		if (retval)
 			return retval;
 	}
 	return 0;
 }
	/*
	* rw_bitmaps.c --- routines to read and write the inode and block bitmaps.
	*
	* Copyright (C) 1993, 1994, 1994, 1996 Theodore Ts'o.
	*
	* %Begin-Header%
	* This file may be redistributed under the terms of the GNU Public
	* License.
	* %End-Header%
	*/

	#include <stdio.h>
	#include <string.h>
	#if HAVE_UNISTD_H
	#include <unistd.h>
	#endif
	#include <fcntl.h>
	#include <time.h>
	#ifdef HAVE_SYS_STAT_H
	#include <sys/stat.h>
	#endif
	#ifdef HAVE_SYS_TYPES_H
	#include <sys/types.h>
	#endif

	#include "ext2_fs.h"
	#include "ext2fs.h"
	#include "e2image.h"

	#if defined(__powerpc__) && defined(EXT2FS_ENABLE_SWAPFS)
	/*
	* On the PowerPC, the big-endian variant of the ext2 filesystem
	* has its bitmaps stored as 32-bit words with bit 0 as the LSB
	* of each word. Thus a bitmap with only bit 0 set would be, as
	* a string of bytes, 00 00 00 01 00 ...
	* To cope with this, we byte-reverse each word of a bitmap if
	* we have a big-endian filesystem, that is, if we are not
	* byte-swapping other word-sized numbers.
	*/
	#define EXT2_BIG_ENDIAN_BITMAPS
	#endif

	#ifdef EXT2_BIG_ENDIAN_BITMAPS
	static void ext2fs_swap_bitmap(ext2_filsys fs, char *bitmap, int nbytes)
	{
	__u32 p = (__u32 ) bitmap;
	int n;

	for (n = nbytes / sizeof(__u32); n > 0; --n, ++p)
	p = ext2fs_swab32(p);
	}
	#endif

	errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
	{
	dgrp_t i;
	size_t nbytes;
	errcode_t retval;
	char * inode_bitmap = fs->inode_map->bitmap;
	char * bitmap_block = NULL;
	blk_t blk;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if (!(fs->flags & EXT2_FLAG_RW))
	return EXT2_ET_RO_FILSYS;
	if (!inode_bitmap)
	return 0;
	nbytes = (size_t) ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);

	retval = ext2fs_get_mem(fs->blocksize, &bitmap_block);
	if (retval)
	return retval;
	memset(bitmap_block, 0xff, fs->blocksize);
	for (i = 0; i < fs->group_desc_count; i++) {
	memcpy(bitmap_block, inode_bitmap, nbytes);
	blk = fs->group_desc[i].bg_inode_bitmap;
	if (blk) {
	#ifdef EXT2_BIG_ENDIAN_BITMAPS
	if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) \|\|
	(fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)))
	ext2fs_swap_bitmap(fs, bitmap_block, nbytes);
	#endif
	retval = io_channel_write_blk(fs->io, blk, 1,
	bitmap_block);
	if (retval)
	return EXT2_ET_INODE_BITMAP_WRITE;
	}
	inode_bitmap += nbytes;
	}
	fs->flags &= ~EXT2_FLAG_IB_DIRTY;
	ext2fs_free_mem(&bitmap_block);
	return 0;
	}

	errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
	{
	dgrp_t i;
	unsigned int j;
	int nbytes;
	unsigned int nbits;
	errcode_t retval;
	char * block_bitmap = fs->block_map->bitmap;
	char * bitmap_block = NULL;
	blk_t blk;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if (!(fs->flags & EXT2_FLAG_RW))
	return EXT2_ET_RO_FILSYS;
	if (!block_bitmap)
	return 0;
	nbytes = EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
	retval = ext2fs_get_mem(fs->blocksize, &bitmap_block);
	if (retval)
	return retval;
	memset(bitmap_block, 0xff, fs->blocksize);
	for (i = 0; i < fs->group_desc_count; i++) {
	memcpy(bitmap_block, block_bitmap, nbytes);
	if (i == fs->group_desc_count - 1) {
	/* Force bitmap padding for the last group */
	nbits = ((fs->super->s_blocks_count
	- fs->super->s_first_data_block)
	% EXT2_BLOCKS_PER_GROUP(fs->super));
	if (nbits)
	for (j = nbits; j < fs->blocksize * 8; j++)
	ext2fs_set_bit(j, bitmap_block);
	}
	blk = fs->group_desc[i].bg_block_bitmap;
	if (blk) {
	#ifdef EXT2_BIG_ENDIAN_BITMAPS
	if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) \|\|
	(fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)))
	ext2fs_swap_bitmap(fs, bitmap_block, nbytes);
	#endif
	retval = io_channel_write_blk(fs->io, blk, 1,
	bitmap_block);
	if (retval)
	return EXT2_ET_BLOCK_BITMAP_WRITE;
	}
	block_bitmap += nbytes;
	}
	fs->flags &= ~EXT2_FLAG_BB_DIRTY;
	ext2fs_free_mem(&bitmap_block);
	return 0;
	}

	static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
	{
	dgrp_t i;
	char block_bitmap = 0, inode_bitmap = 0;
	char *buf;
	errcode_t retval;
	int block_nbytes = (int) EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
	int inode_nbytes = (int) EXT2_INODES_PER_GROUP(fs->super) / 8;
	blk_t blk;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	fs->write_bitmaps = ext2fs_write_bitmaps;

	retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
	if (retval)
	return retval;
	if (do_block) {
	if (fs->block_map)
	ext2fs_free_block_bitmap(fs->block_map);
	sprintf(buf, "block bitmap for %s", fs->device_name);
	retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
	if (retval)
	goto cleanup;
	block_bitmap = fs->block_map->bitmap;
	}
	if (do_inode) {
	if (fs->inode_map)
	ext2fs_free_inode_bitmap(fs->inode_map);
	sprintf(buf, "inode bitmap for %s", fs->device_name);
	retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
	if (retval)
	goto cleanup;
	inode_bitmap = fs->inode_map->bitmap;
	}
	ext2fs_free_mem(&buf);

	if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
	if (inode_bitmap) {
	blk = (fs->image_header->offset_inodemap /
	fs->blocksize);
	retval = io_channel_read_blk(fs->image_io, blk,
	-(inode_nbytes * fs->group_desc_count),
	inode_bitmap);
	if (retval)
	goto cleanup;
	}
	if (block_bitmap) {
	blk = (fs->image_header->offset_blockmap /
	fs->blocksize);
	retval = io_channel_read_blk(fs->image_io, blk,
	-(block_nbytes * fs->group_desc_count),
	block_bitmap);
	if (retval)
	goto cleanup;
	}
	return 0;
	}

	for (i = 0; i < fs->group_desc_count; i++) {
	if (block_bitmap) {
	blk = fs->group_desc[i].bg_block_bitmap;
	if (blk) {
	retval = io_channel_read_blk(fs->io, blk,
	-block_nbytes, block_bitmap);
	if (retval) {
	retval = EXT2_ET_BLOCK_BITMAP_READ;
	goto cleanup;
	}
	#ifdef EXT2_BIG_ENDIAN_BITMAPS
	if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) \|\|
	(fs->flags & EXT2_FLAG_SWAP_BYTES_READ)))
	ext2fs_swap_bitmap(fs, block_bitmap, block_nbytes);
	#endif
	} else
	memset(block_bitmap, 0, block_nbytes);
	block_bitmap += block_nbytes;
	}
	if (inode_bitmap) {
	blk = fs->group_desc[i].bg_inode_bitmap;
	if (blk) {
	retval = io_channel_read_blk(fs->io, blk,
	-inode_nbytes, inode_bitmap);
	if (retval) {
	retval = EXT2_ET_INODE_BITMAP_READ;
	goto cleanup;
	}
	#ifdef EXT2_BIG_ENDIAN_BITMAPS
	if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) \|\|
	(fs->flags & EXT2_FLAG_SWAP_BYTES_READ)))
	ext2fs_swap_bitmap(fs, inode_bitmap, inode_nbytes);
	#endif
	} else
	memset(inode_bitmap, 0, inode_nbytes);
	inode_bitmap += inode_nbytes;
	}
	}
	return 0;

	cleanup:
	if (do_block) {
	ext2fs_free_mem(&fs->block_map);
	fs->block_map = 0;
	}
	if (do_inode) {
	ext2fs_free_mem(&fs->inode_map);
	fs->inode_map = 0;
	}
	if (buf)
	ext2fs_free_mem(&buf);
	return retval;
	}

	errcode_t ext2fs_read_inode_bitmap (ext2_filsys fs)
	{
	return read_bitmaps(fs, 1, 0);
	}

	errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
	{
	return read_bitmaps(fs, 0, 1);
	}

	errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
	{

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if (fs->inode_map && fs->block_map)
	return 0;

	return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
	}

	errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
	{
	errcode_t retval;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if (fs->block_map && ext2fs_test_bb_dirty(fs)) {
	retval = ext2fs_write_block_bitmap(fs);
	if (retval)
	return retval;
	}
	if (fs->inode_map && ext2fs_test_ib_dirty(fs)) {
	retval = ext2fs_write_inode_bitmap(fs);
	if (retval)
	return retval;
	}
	return 0;
	}