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https://github.com/sheumann/hush.git
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297 lines
7.3 KiB
C
297 lines
7.3 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* rw_bitmaps.c --- routines to read and write the inode and block bitmaps.
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*
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* Copyright (C) 1993, 1994, 1994, 1996 Theodore Ts'o.
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*
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* %Begin-Header%
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* This file may be redistributed under the terms of the GNU Public
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* License.
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* %End-Header%
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*/
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#include <stdio.h>
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#include <string.h>
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#if HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <fcntl.h>
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#include <time.h>
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#ifdef HAVE_SYS_STAT_H
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#include <sys/stat.h>
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#endif
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#ifdef HAVE_SYS_TYPES_H
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#include <sys/types.h>
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#endif
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#include "ext2_fs.h"
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#include "ext2fs.h"
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#include "e2image.h"
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#if defined(__powerpc__) && BB_BIG_ENDIAN
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/*
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* On the PowerPC, the big-endian variant of the ext2 filesystem
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* has its bitmaps stored as 32-bit words with bit 0 as the LSB
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* of each word. Thus a bitmap with only bit 0 set would be, as
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* a string of bytes, 00 00 00 01 00 ...
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* To cope with this, we byte-reverse each word of a bitmap if
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* we have a big-endian filesystem, that is, if we are *not*
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* byte-swapping other word-sized numbers.
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*/
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#define EXT2_BIG_ENDIAN_BITMAPS
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#endif
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#ifdef EXT2_BIG_ENDIAN_BITMAPS
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static void ext2fs_swap_bitmap(ext2_filsys fs, char *bitmap, int nbytes)
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{
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__u32 *p = (__u32 *) bitmap;
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int n;
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for (n = nbytes / sizeof(__u32); n > 0; --n, ++p)
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*p = ext2fs_swab32(*p);
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}
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#endif
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errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
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{
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dgrp_t i;
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size_t nbytes;
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errcode_t retval;
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char * inode_bitmap = fs->inode_map->bitmap;
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char * bitmap_block = NULL;
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blk_t blk;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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if (!(fs->flags & EXT2_FLAG_RW))
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return EXT2_ET_RO_FILSYS;
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if (!inode_bitmap)
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return 0;
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nbytes = (size_t) ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
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retval = ext2fs_get_mem(fs->blocksize, &bitmap_block);
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if (retval)
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return retval;
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memset(bitmap_block, 0xff, fs->blocksize);
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for (i = 0; i < fs->group_desc_count; i++) {
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memcpy(bitmap_block, inode_bitmap, nbytes);
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blk = fs->group_desc[i].bg_inode_bitmap;
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if (blk) {
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#ifdef EXT2_BIG_ENDIAN_BITMAPS
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if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
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(fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)))
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ext2fs_swap_bitmap(fs, bitmap_block, nbytes);
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#endif
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retval = io_channel_write_blk(fs->io, blk, 1,
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bitmap_block);
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if (retval)
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return EXT2_ET_INODE_BITMAP_WRITE;
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}
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inode_bitmap += nbytes;
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}
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fs->flags &= ~EXT2_FLAG_IB_DIRTY;
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ext2fs_free_mem(&bitmap_block);
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return 0;
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}
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errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
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{
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dgrp_t i;
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unsigned int j;
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int nbytes;
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unsigned int nbits;
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errcode_t retval;
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char * block_bitmap = fs->block_map->bitmap;
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char * bitmap_block = NULL;
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blk_t blk;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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if (!(fs->flags & EXT2_FLAG_RW))
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return EXT2_ET_RO_FILSYS;
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if (!block_bitmap)
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return 0;
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nbytes = EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
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retval = ext2fs_get_mem(fs->blocksize, &bitmap_block);
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if (retval)
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return retval;
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memset(bitmap_block, 0xff, fs->blocksize);
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for (i = 0; i < fs->group_desc_count; i++) {
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memcpy(bitmap_block, block_bitmap, nbytes);
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if (i == fs->group_desc_count - 1) {
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/* Force bitmap padding for the last group */
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nbits = ((fs->super->s_blocks_count
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- fs->super->s_first_data_block)
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% EXT2_BLOCKS_PER_GROUP(fs->super));
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if (nbits)
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for (j = nbits; j < fs->blocksize * 8; j++)
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ext2fs_set_bit(j, bitmap_block);
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}
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blk = fs->group_desc[i].bg_block_bitmap;
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if (blk) {
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#ifdef EXT2_BIG_ENDIAN_BITMAPS
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if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
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(fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)))
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ext2fs_swap_bitmap(fs, bitmap_block, nbytes);
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#endif
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retval = io_channel_write_blk(fs->io, blk, 1,
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bitmap_block);
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if (retval)
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return EXT2_ET_BLOCK_BITMAP_WRITE;
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}
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block_bitmap += nbytes;
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}
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fs->flags &= ~EXT2_FLAG_BB_DIRTY;
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ext2fs_free_mem(&bitmap_block);
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return 0;
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}
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static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
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{
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dgrp_t i;
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char *block_bitmap = 0, *inode_bitmap = 0;
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char *buf;
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errcode_t retval;
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int block_nbytes = (int) EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
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int inode_nbytes = (int) EXT2_INODES_PER_GROUP(fs->super) / 8;
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blk_t blk;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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fs->write_bitmaps = ext2fs_write_bitmaps;
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retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
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if (retval)
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return retval;
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if (do_block) {
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ext2fs_free_block_bitmap(fs->block_map);
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sprintf(buf, "block bitmap for %s", fs->device_name);
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retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
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if (retval)
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goto cleanup;
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block_bitmap = fs->block_map->bitmap;
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}
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if (do_inode) {
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ext2fs_free_inode_bitmap(fs->inode_map);
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sprintf(buf, "inode bitmap for %s", fs->device_name);
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retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
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if (retval)
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goto cleanup;
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inode_bitmap = fs->inode_map->bitmap;
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}
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ext2fs_free_mem(&buf);
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if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
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if (inode_bitmap) {
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blk = (fs->image_header->offset_inodemap /
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fs->blocksize);
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retval = io_channel_read_blk(fs->image_io, blk,
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-(inode_nbytes * fs->group_desc_count),
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inode_bitmap);
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if (retval)
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goto cleanup;
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}
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if (block_bitmap) {
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blk = (fs->image_header->offset_blockmap /
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fs->blocksize);
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retval = io_channel_read_blk(fs->image_io, blk,
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-(block_nbytes * fs->group_desc_count),
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block_bitmap);
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if (retval)
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goto cleanup;
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}
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return 0;
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}
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for (i = 0; i < fs->group_desc_count; i++) {
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if (block_bitmap) {
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blk = fs->group_desc[i].bg_block_bitmap;
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if (blk) {
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retval = io_channel_read_blk(fs->io, blk,
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-block_nbytes, block_bitmap);
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if (retval) {
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retval = EXT2_ET_BLOCK_BITMAP_READ;
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goto cleanup;
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}
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#ifdef EXT2_BIG_ENDIAN_BITMAPS
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if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
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(fs->flags & EXT2_FLAG_SWAP_BYTES_READ)))
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ext2fs_swap_bitmap(fs, block_bitmap, block_nbytes);
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#endif
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} else
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memset(block_bitmap, 0, block_nbytes);
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block_bitmap += block_nbytes;
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}
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if (inode_bitmap) {
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blk = fs->group_desc[i].bg_inode_bitmap;
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if (blk) {
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retval = io_channel_read_blk(fs->io, blk,
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-inode_nbytes, inode_bitmap);
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if (retval) {
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retval = EXT2_ET_INODE_BITMAP_READ;
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goto cleanup;
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}
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#ifdef EXT2_BIG_ENDIAN_BITMAPS
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if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
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(fs->flags & EXT2_FLAG_SWAP_BYTES_READ)))
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ext2fs_swap_bitmap(fs, inode_bitmap, inode_nbytes);
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#endif
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} else
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memset(inode_bitmap, 0, inode_nbytes);
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inode_bitmap += inode_nbytes;
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}
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}
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return 0;
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cleanup:
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if (do_block) {
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ext2fs_free_mem(&fs->block_map);
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}
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if (do_inode) {
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ext2fs_free_mem(&fs->inode_map);
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}
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ext2fs_free_mem(&buf);
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return retval;
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}
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errcode_t ext2fs_read_inode_bitmap (ext2_filsys fs)
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{
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return read_bitmaps(fs, 1, 0);
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}
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errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
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{
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return read_bitmaps(fs, 0, 1);
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}
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errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
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{
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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if (fs->inode_map && fs->block_map)
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return 0;
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return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
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}
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errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
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{
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errcode_t retval;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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if (fs->block_map && ext2fs_test_bb_dirty(fs)) {
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retval = ext2fs_write_block_bitmap(fs);
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if (retval)
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return retval;
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}
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if (fs->inode_map && ext2fs_test_ib_dirty(fs)) {
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retval = ext2fs_write_inode_bitmap(fs);
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if (retval)
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return retval;
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}
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return 0;
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}
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