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;
+}