/* vi: set sw=4 ts=4: *//* * openfs.c --- open an ext2 filesystem * * Copyright (C) 1993, 1994, 1995, 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>#if HAVE_SYS_STAT_H#include <sys/stat.h>#endif#if HAVE_SYS_TYPES_H#include <sys/types.h>#endif#include "ext2_fs.h"#include "ext2fs.h"#include "e2image.h"blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i){	int	bg;	int	has_super = 0;	int	ret_blk;	if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||	    (i < fs->super->s_first_meta_bg))		return (group_block + i + 1);	bg = (fs->blocksize / sizeof (struct ext2_group_desc)) * i;	if (ext2fs_bg_has_super(fs, bg))		has_super = 1;	ret_blk = (fs->super->s_first_data_block + has_super +		   (bg * fs->super->s_blocks_per_group));	/*	 * If group_block is not the normal value, we're trying to use	 * the backup group descriptors and superblock --- so use the	 * alternate location of the second block group in the	 * metablock group.  Ideally we should be testing each bg	 * descriptor block individually for correctness, but we don't	 * have the infrastructure in place to do that.	 */	if (group_block != fs->super->s_first_data_block &&	    ((ret_blk + fs->super->s_blocks_per_group) <	     fs->super->s_blocks_count))		ret_blk += fs->super->s_blocks_per_group;	return ret_blk;}errcode_t ext2fs_open(const char *name, int flags, int superblock,		      unsigned int block_size, io_manager manager,		      ext2_filsys *ret_fs){	return ext2fs_open2(name, 0, flags, superblock, block_size,			    manager, ret_fs);}/* *  Note: if superblock is non-zero, block-size must also be non-zero. *	Superblock and block_size can be zero to use the default size. * * Valid flags for ext2fs_open() * *	EXT2_FLAG_RW	- Open the filesystem for read/write. *	EXT2_FLAG_FORCE - Open the filesystem even if some of the *				features aren't supported. *	EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device */errcode_t ext2fs_open2(const char *name, const char *io_options,		       int flags, int superblock,		       unsigned int block_size, io_manager manager,		       ext2_filsys *ret_fs){	ext2_filsys	fs;	errcode_t	retval;	unsigned long	i;	int		groups_per_block, blocks_per_group;	blk_t		group_block, blk;	char		*dest, *cp;#if BB_BIG_ENDIAN	int j;	struct ext2_group_desc *gdp;#endif	EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);	retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);	if (retval)		return retval;	memset(fs, 0, sizeof(struct struct_ext2_filsys));	fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;	fs->flags = flags;	fs->umask = 022;	retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);	if (retval)		goto cleanup;	strcpy(fs->device_name, name);	cp = strchr(fs->device_name, '?');	if (!io_options && cp) {		*cp++ = 0;		io_options = cp;	}	retval = manager->open(fs->device_name,			       (flags & EXT2_FLAG_RW) ? IO_FLAG_RW : 0,			       &fs->io);	if (retval)		goto cleanup;	if (io_options &&	    (retval = io_channel_set_options(fs->io, io_options)))		goto cleanup;	fs->image_io = fs->io;	fs->io->app_data = fs;	retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->super);	if (retval)		goto cleanup;	if (flags & EXT2_FLAG_IMAGE_FILE) {		retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),					&fs->image_header);		if (retval)			goto cleanup;		retval = io_channel_read_blk(fs->io, 0,					     -(int)sizeof(struct ext2_image_hdr),					     fs->image_header);		if (retval)			goto cleanup;		if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)			return EXT2_ET_MAGIC_E2IMAGE;		superblock = 1;		block_size = fs->image_header->fs_blocksize;	}	/*	 * If the user specifies a specific block # for the	 * superblock, then he/she must also specify the block size!	 * Otherwise, read the master superblock located at offset	 * SUPERBLOCK_OFFSET from the start of the partition.	 *	 * Note: we only save a backup copy of the superblock if we	 * are reading the superblock from the primary superblock location.	 */	if (superblock) {		if (!block_size) {			retval = EXT2_ET_INVALID_ARGUMENT;			goto cleanup;		}		io_channel_set_blksize(fs->io, block_size);		group_block = superblock;		fs->orig_super = 0;	} else {		io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);		superblock = 1;		group_block = 0;		retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);		if (retval)			goto cleanup;	}	retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,				     fs->super);	if (retval)		goto cleanup;	if (fs->orig_super)		memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);#if BB_BIG_ENDIAN	if ((fs->super->s_magic == ext2fs_swab16(EXT2_SUPER_MAGIC)) ||	    (fs->flags & EXT2_FLAG_SWAP_BYTES)) {		fs->flags |= EXT2_FLAG_SWAP_BYTES;		ext2fs_swap_super(fs->super);	}#endif	if (fs->super->s_magic != EXT2_SUPER_MAGIC) {		retval = EXT2_ET_BAD_MAGIC;		goto cleanup;	}	if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {		retval = EXT2_ET_REV_TOO_HIGH;		goto cleanup;	}	/*	 * Check for feature set incompatibility	 */	if (!(flags & EXT2_FLAG_FORCE)) {		if (fs->super->s_feature_incompat &		    ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {			retval = EXT2_ET_UNSUPP_FEATURE;			goto cleanup;		}		if ((flags & EXT2_FLAG_RW) &&		    (fs->super->s_feature_ro_compat &		     ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {			retval = EXT2_ET_RO_UNSUPP_FEATURE;			goto cleanup;		}		if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&		    (fs->super->s_feature_incompat &		     EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {			retval = EXT2_ET_UNSUPP_FEATURE;			goto cleanup;		}	}	fs->blocksize = EXT2_BLOCK_SIZE(fs->super);	if (fs->blocksize == 0) {		retval = EXT2_ET_CORRUPT_SUPERBLOCK;		goto cleanup;	}	fs->fragsize = EXT2_FRAG_SIZE(fs->super);	fs->inode_blocks_per_group = ((fs->super->s_inodes_per_group *				       EXT2_INODE_SIZE(fs->super) +				       EXT2_BLOCK_SIZE(fs->super) - 1) /				      EXT2_BLOCK_SIZE(fs->super));	if (block_size) {		if (block_size != fs->blocksize) {			retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;			goto cleanup;		}	}	/*	 * Set the blocksize to the filesystem's blocksize.	 */	io_channel_set_blksize(fs->io, fs->blocksize);	/*	 * If this is an external journal device, don't try to read	 * the group descriptors, because they're not there.	 */	if (fs->super->s_feature_incompat &	    EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {		fs->group_desc_count = 0;		*ret_fs = fs;		return 0;	}	/*	 * Read group descriptors	 */	blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);	if (blocks_per_group == 0 ||	    blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||	    fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super)) {		retval = EXT2_ET_CORRUPT_SUPERBLOCK;		goto cleanup;	}	fs->group_desc_count = (fs->super->s_blocks_count -				fs->super->s_first_data_block +				blocks_per_group - 1) / blocks_per_group;	fs->desc_blocks = (fs->group_desc_count +			   EXT2_DESC_PER_BLOCK(fs->super) - 1)		/ EXT2_DESC_PER_BLOCK(fs->super);	retval = ext2fs_get_mem(fs->desc_blocks * fs->blocksize,				&fs->group_desc);	if (retval)		goto cleanup;	if (!group_block)		group_block = fs->super->s_first_data_block;	dest = (char *) fs->group_desc;	groups_per_block = fs->blocksize / sizeof(struct ext2_group_desc);	for (i=0 ; i < fs->desc_blocks; i++) {		blk = ext2fs_descriptor_block_loc(fs, group_block, i);		retval = io_channel_read_blk(fs->io, blk, 1, dest);		if (retval)			goto cleanup;#if BB_BIG_ENDIAN		if (fs->flags & EXT2_FLAG_SWAP_BYTES) {			gdp = (struct ext2_group_desc *) dest;			for (j=0; j < groups_per_block; j++)				ext2fs_swap_group_desc(gdp++);		}#endif		dest += fs->blocksize;	}	*ret_fs = fs;	return 0;cleanup:	ext2fs_free(fs);	return retval;}/* * Set/get the filesystem data I/O channel. * * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true. */errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io){	if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)		return EXT2_ET_NOT_IMAGE_FILE;	if (old_io) {		*old_io = (fs->image_io == fs->io) ? 0 : fs->io;	}	return 0;}errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io){	if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)		return EXT2_ET_NOT_IMAGE_FILE;	fs->io = new_io ? new_io : fs->image_io;	return 0;}errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io){	if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)		return EXT2_ET_NOT_IMAGE_FILE;	fs->io = fs->image_io = new_io;	fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |		EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;	fs->flags &= ~EXT2_FLAG_IMAGE_FILE;	return 0;}