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-rw-r--r--e2fslib/rw_bitmaps.c302
1 files changed, 302 insertions, 0 deletions
diff --git a/e2fslib/rw_bitmaps.c b/e2fslib/rw_bitmaps.c
new file mode 100644
index 0000000..89557db
--- /dev/null
+++ b/e2fslib/rw_bitmaps.c
@@ -0,0 +1,302 @@
+/*
+ * 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
+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, (void **) &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_CHANGED;
+ fs->flags &= ~EXT2_FLAG_IB_DIRTY;
+ ext2fs_free_mem((void **) &bitmap_block);
+ return 0;
+}
+
+errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
+{
+ dgrp_t i;
+ int j;
+ int nbytes;
+ 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, (void **) &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 = (int) ((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_CHANGED;
+ fs->flags &= ~EXT2_FLAG_BB_DIRTY;
+ ext2fs_free_mem((void **) &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, (void **) &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((void **) &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->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->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((void **) &fs->block_map);
+ fs->block_map = 0;
+ }
+ if (do_inode) {
+ ext2fs_free_mem((void **) &fs->inode_map);
+ fs->inode_map = 0;
+ }
+ if (buf)
+ ext2fs_free_mem((void **) &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;
+}
+