aboutsummaryrefslogtreecommitdiff
path: root/e2fsprogs/ext2fs/openfs.c
diff options
context:
space:
mode:
Diffstat (limited to 'e2fsprogs/ext2fs/openfs.c')
-rw-r--r--e2fsprogs/ext2fs/openfs.c326
1 files changed, 326 insertions, 0 deletions
diff --git a/e2fsprogs/ext2fs/openfs.c b/e2fsprogs/ext2fs/openfs.c
new file mode 100644
index 000000000..d27c1b913
--- /dev/null
+++ b/e2fsprogs/ext2fs/openfs.c
@@ -0,0 +1,326 @@
+/*
+ * 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 j, groups_per_block, blocks_per_group;
+ blk_t group_block, blk;
+ char *dest, *cp;
+ struct ext2_group_desc *gdp;
+
+ 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);
+
+#ifdef EXT2FS_ENABLE_SWAPFS
+ 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;
+#ifdef EXT2FS_ENABLE_SWAPFS
+ 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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 06:25:43 +0000