Add libfsimage, a C library for reading files from filesystem images.

Initial support is provided for Solaris UFS, ext2 (both using libext2fs
and not), and reiserfs.

Signed-off-by: John Levon <john.levon@sun.com>

2 files changed, 1267 insertions, 0 deletions

diff --git a/tools/libfsimage/reiserfs/Makefile b/tools/libfsimage/reiserfs/Makefile
new file mode 100644
index 0000000000..c71fff8843
--- /dev/null
+++ b/tools/libfsimage/reiserfs/Makefile
@@ -0,0 +1,13 @@
+XEN_ROOT = ../../..
+
+LIB_SRCS-y = fsys_reiserfs.c
+
+FS = reiserfs
+
+.PHONY: all
+all: fs-all
+
+.PHONY: install
+install: fs-install
+
+include $(XEN_ROOT)/tools/libfsimage/Rules.mk
diff --git a/tools/libfsimage/reiserfs/fsys_reiserfs.c b/tools/libfsimage/reiserfs/fsys_reiserfs.c
new file mode 100644
index 0000000000..132821d7ac
--- /dev/null
+++ b/tools/libfsimage/reiserfs/fsys_reiserfs.c
@@ -0,0 +1,1254 @@
+/* fsys_reiserfs.c - an implementation for the ReiserFS filesystem */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2000, 2001  Free Software Foundation, Inc.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <fsimage_grub.h>
+
+#undef REISERDEBUG
+
+/* Some parts of this code (mainly the structures and defines) are
+ * from the original reiser fs code, as found in the linux kernel.
+ */
+
+/* include/asm-i386/types.h */
+typedef __signed__ char __s8;
+typedef unsigned char __u8;
+typedef __signed__ short __s16;
+typedef unsigned short __u16;
+typedef __signed__ int __s32;
+typedef unsigned int __u32;
+typedef unsigned long long __u64;
+
+/* linux/posix_type.h */
+typedef long linux_off_t;
+
+/* linux/little_endian.h */
+#define __cpu_to_le64(x) ((__u64) (x))
+#define __le64_to_cpu(x) ((__u64) (x))
+#define __cpu_to_le32(x) ((__u32) (x))
+#define __le32_to_cpu(x) ((__u32) (x))
+#define __cpu_to_le16(x) ((__u16) (x))
+#define __le16_to_cpu(x) ((__u16) (x))
+
+/* include/linux/reiser_fs.h */
+/* This is the new super block of a journaling reiserfs system */
+struct reiserfs_super_block
+{
+  __u32 s_block_count;			/* blocks count         */
+  __u32 s_free_blocks;                  /* free blocks count    */
+  __u32 s_root_block;           	/* root block number    */
+  __u32 s_journal_block;           	/* journal block number    */
+  __u32 s_journal_dev;           	/* journal device number  */
+  __u32 s_journal_size; 		/* size of the journal on FS creation.  used to make sure they don't overflow it */
+  __u32 s_journal_trans_max;            /* max number of blocks in a transaction.  */
+  __u32 s_journal_magic;                /* random value made on fs creation */
+  __u32 s_journal_max_batch;            /* max number of blocks to batch into a trans */
+  __u32 s_journal_max_commit_age;       /* in seconds, how old can an async commit be */
+  __u32 s_journal_max_trans_age;        /* in seconds, how old can a transaction be */
+  __u16 s_blocksize;                   	/* block size           */
+  __u16 s_oid_maxsize;			/* max size of object id array  */
+  __u16 s_oid_cursize;			/* current size of object id array */
+  __u16 s_state;                       	/* valid or error       */
+  char s_magic[16];                     /* reiserfs magic string indicates that file system is reiserfs */
+  __u16 s_tree_height;                  /* height of disk tree */
+  __u16 s_bmap_nr;                      /* amount of bitmap blocks needed to address each block of file system */
+  __u16 s_version;
+  char s_unused[128];			/* zero filled by mkreiserfs */
+};
+
+#define REISERFS_MAX_SUPPORTED_VERSION 2
+#define REISERFS_SUPER_MAGIC_STRING "ReIsErFs"
+#define REISER2FS_SUPER_MAGIC_STRING "ReIsEr2Fs"
+#define REISER3FS_SUPER_MAGIC_STRING "ReIsEr3Fs"
+
+#define MAX_HEIGHT 7
+
+/* must be correct to keep the desc and commit structs at 4k */
+#define JOURNAL_TRANS_HALF 1018
+
+/* first block written in a commit.  */
+struct reiserfs_journal_desc {
+  __u32 j_trans_id;			/* id of commit */
+  __u32 j_len;				/* length of commit. len +1 is the commit block */
+  __u32 j_mount_id;			/* mount id of this trans*/
+  __u32 j_realblock[JOURNAL_TRANS_HALF]; /* real locations for the first blocks */
+  char j_magic[12];
+};
+
+/* last block written in a commit */
+struct reiserfs_journal_commit {
+  __u32 j_trans_id;			/* must match j_trans_id from the desc block */
+  __u32 j_len;			/* ditto */
+  __u32 j_realblock[JOURNAL_TRANS_HALF]; /* real locations for the last blocks */
+  char j_digest[16];			/* md5 sum of all the blocks involved, including desc and commit. not used, kill it */
+};
+
+/* this header block gets written whenever a transaction is considered
+   fully flushed, and is more recent than the last fully flushed
+   transaction.  
+   fully flushed means all the log blocks and all the real blocks are
+   on disk, and this transaction does not need to be replayed.  
+*/
+struct reiserfs_journal_header {
+  /* id of last fully flushed transaction */
+  __u32 j_last_flush_trans_id;
+  /* offset in the log of where to start replay after a crash */
+  __u32 j_first_unflushed_offset;
+  /* mount id to detect very old transactions */
+  __u32 j_mount_id;
+};
+
+/* magic string to find desc blocks in the journal */
+#define JOURNAL_DESC_MAGIC "ReIsErLB" 
+
+
+/*
+ * directories use this key as well as old files
+ */
+struct offset_v1
+{
+  /*
+   * for regular files this is the offset to the first byte of the
+   * body, contained in the object-item, as measured from the start of
+   * the entire body of the object.
+   *
+   * for directory entries, k_offset consists of hash derived from
+   * hashing the name and using few bits (23 or more) of the resulting
+   * hash, and generation number that allows distinguishing names with
+   * hash collisions. If number of collisions overflows generation
+   * number, we return EEXIST.  High order bit is 0 always 
+   */
+  __u32 k_offset;
+  __u32 k_uniqueness;
+};
+
+struct offset_v2
+{
+  /*
+   * for regular files this is the offset to the first byte of the
+   * body, contained in the object-item, as measured from the start of
+   * the entire body of the object.
+   *
+   * for directory entries, k_offset consists of hash derived from
+   * hashing the name and using few bits (23 or more) of the resulting
+   * hash, and generation number that allows distinguishing names with
+   * hash collisions. If number of collisions overflows generation
+   * number, we return EEXIST.  High order bit is 0 always 
+   */
+  __u64 k_offset:60;
+  __u64 k_type: 4;
+};
+
+
+struct key
+{
+  /* packing locality: by default parent directory object id */
+  __u32 k_dir_id;
+  /* object identifier */
+  __u32 k_objectid;
+  /* the offset and node type (old and new form) */
+  union
+  {
+    struct offset_v1 v1;
+    struct offset_v2 v2;
+  }
+  u;
+};
+
+#define KEY_SIZE (sizeof (struct key))
+
+/* Header of a disk block.  More precisely, header of a formatted leaf
+   or internal node, and not the header of an unformatted node. */
+struct block_head
+{       
+  __u16 blk_level;        /* Level of a block in the tree. */
+  __u16 blk_nr_item;      /* Number of keys/items in a block. */
+  __u16 blk_free_space;   /* Block free space in bytes. */
+  struct key  blk_right_delim_key; /* Right delimiting key for this block (supported for leaf level nodes
+				      only) */
+};
+#define BLKH_SIZE (sizeof (struct block_head))
+#define DISK_LEAF_NODE_LEVEL  1 /* Leaf node level.                       */
+
+struct item_head
+{
+  struct key ih_key; 	/* Everything in the tree is found by searching for it based on its key.*/
+  
+  union
+  {
+    __u16 ih_free_space; /* The free space in the last unformatted node of an indirect item if this
+			    is an indirect item.  This equals 0xFFFF iff this is a direct item or
+			    stat data item. Note that the key, not this field, is used to determine
+			    the item type, and thus which field this union contains. */
+    __u16 ih_entry_count; /* Iff this is a directory item, this field equals the number of directory
+			     entries in the directory item. */
+  }
+  u;
+  __u16 ih_item_len;           /* total size of the item body                  */
+  __u16 ih_item_location;      /* an offset to the item body within the block  */
+  __u16 ih_version;	       /* ITEM_VERSION_1 for all old items, 
+				  ITEM_VERSION_2 for new ones. 
+				  Highest bit is set by fsck
+                                  temporary, cleaned after all done */
+};
+/* size of item header     */
+#define IH_SIZE (sizeof (struct item_head))
+
+#define ITEM_VERSION_1 0
+#define ITEM_VERSION_2 1
+#define IH_KEY_OFFSET(ih) ((ih)->ih_version == ITEM_VERSION_1 \
+			   ? (ih)->ih_key.u.v1.k_offset \
+			   : (ih)->ih_key.u.v2.k_offset)
+
+#define IH_KEY_ISTYPE(ih, type) ((ih)->ih_version == ITEM_VERSION_1 \
+				 ? (ih)->ih_key.u.v1.k_uniqueness == V1_##type \
+				 : (ih)->ih_key.u.v2.k_type == V2_##type)
+
+struct disk_child
+{
+  unsigned long       dc_block_number;              /* Disk child's block number. */
+  unsigned short      dc_size;		            /* Disk child's used space.   */
+};
+
+#define DC_SIZE (sizeof (struct disk_child))
+
+/* Stat Data on disk.
+ *
+ * Note that reiserfs has two different forms of stat data.  Luckily
+ * the fields needed by grub are at the same position.
+ */
+struct stat_data
+{
+  __u16 sd_mode;	/* file type, permissions */
+  __u16 sd_notused1[3]; /* fields not needed by reiserfs */
+  __u32 sd_size;	/* file size */
+  __u32 sd_size_hi;	/* file size high 32 bits (since version 2) */
+};
+
+struct reiserfs_de_head
+{
+  __u32 deh_offset;  /* third component of the directory entry key */
+  __u32 deh_dir_id;  /* objectid of the parent directory of the
+			object, that is referenced by directory entry */
+  __u32 deh_objectid;/* objectid of the object, that is referenced by
+                        directory entry */
+  __u16 deh_location;/* offset of name in the whole item */
+  __u16 deh_state;   /* whether 1) entry contains stat data (for
+			future), and 2) whether entry is hidden
+			(unlinked) */
+};
+
+#define DEH_SIZE (sizeof (struct reiserfs_de_head))
+
+#define DEH_Statdata (1 << 0)			/* not used now */
+#define DEH_Visible  (1 << 2)
+
+#define SD_OFFSET  0
+#define SD_UNIQUENESS 0
+#define DOT_OFFSET 1
+#define DOT_DOT_OFFSET 2
+#define DIRENTRY_UNIQUENESS 500
+
+#define V1_TYPE_STAT_DATA 0x0
+#define V1_TYPE_DIRECT 0xffffffff
+#define V1_TYPE_INDIRECT 0xfffffffe
+#define V1_TYPE_DIRECTORY_MAX 0xfffffffd
+#define V2_TYPE_STAT_DATA 0
+#define V2_TYPE_INDIRECT 1
+#define V2_TYPE_DIRECT 2
+#define V2_TYPE_DIRENTRY 3 
+
+#define REISERFS_ROOT_OBJECTID 2
+#define REISERFS_ROOT_PARENT_OBJECTID 1
+#define REISERFS_DISK_OFFSET_IN_BYTES (64 * 1024)
+/* the spot for the super in versions 3.5 - 3.5.11 (inclusive) */
+#define REISERFS_OLD_DISK_OFFSET_IN_BYTES (8 * 1024)
+#define REISERFS_OLD_BLOCKSIZE 4096
+
+#define S_ISREG(mode) (((mode) & 0170000) == 0100000)
+#define S_ISDIR(mode) (((mode) & 0170000) == 0040000)
+#define S_ISLNK(mode) (((mode) & 0170000) == 0120000)
+
+#define PATH_MAX       1024	/* include/linux/limits.h */
+#define MAX_LINK_COUNT    5	/* number of symbolic links to follow */
+
+/* The size of the node cache */
+#define FSYSREISER_CACHE_SIZE 24*1024
+#define FSYSREISER_MIN_BLOCKSIZE SECTOR_SIZE
+#define FSYSREISER_MAX_BLOCKSIZE FSYSREISER_CACHE_SIZE / 3
+
+/* Info about currently opened file */
+struct fsys_reiser_fileinfo
+{
+  __u32 k_dir_id;
+  __u32 k_objectid;
+};
+
+/* In memory info about the currently mounted filesystem */
+struct fsys_reiser_info
+{
+  /* The last read item head */
+  struct item_head *current_ih;
+  /* The last read item */
+  char *current_item;
+  /* The information for the currently opened file */
+  struct fsys_reiser_fileinfo fileinfo;
+  /* The start of the journal */
+  __u32 journal_block;
+  /* The size of the journal */
+  __u32 journal_block_count;
+  /* The first valid descriptor block in journal
+     (relative to journal_block) */
+  __u32 journal_first_desc;
+
+  /* The ReiserFS version. */
+  __u16 version;
+  /* The current depth of the reiser tree. */
+  __u16 tree_depth;
+  /* SECTOR_SIZE << blocksize_shift == blocksize. */
+  __u8  blocksize_shift;
+  /* 1 << full_blocksize_shift == blocksize. */
+  __u8  fullblocksize_shift;
+  /* The reiserfs block size  (must be a power of 2) */
+  __u16 blocksize;
+  /* The number of cached tree nodes */
+  __u16 cached_slots;
+  /* The number of valid transactions in journal */
+  __u16 journal_transactions;
+  
+  unsigned int blocks[MAX_HEIGHT];
+  unsigned int next_key_nr[MAX_HEIGHT];
+};
+
+/* The cached s+tree blocks in FSYS_BUF,  see below
+ * for a more detailed description.
+ */
+#define ROOT     ((char *) FSYS_BUF)
+#define CACHE(i) (ROOT + ((i) << INFO->fullblocksize_shift))
+#define LEAF     CACHE (DISK_LEAF_NODE_LEVEL)
+
+#define BLOCKHEAD(cache) ((struct block_head *) cache)
+#define ITEMHEAD         ((struct item_head  *) ((char *) LEAF + BLKH_SIZE))
+#define KEY(cache)       ((struct key        *) ((char *) cache + BLKH_SIZE))
+#define DC(cache)        ((struct disk_child *) \
+			  ((char *) cache + BLKH_SIZE + KEY_SIZE * nr_item))
+/* The fsys_reiser_info block.
+ */
+#define INFO \
+    ((struct fsys_reiser_info *) ((char *) FSYS_BUF + FSYSREISER_CACHE_SIZE))
+/* 
+ * The journal cache.  For each transaction it contains the number of
+ * blocks followed by the real block numbers of this transaction.  
+ *
+ * If the block numbers of some transaction won't fit in this space,
+ * this list is stopped with a 0xffffffff marker and the remaining
+ * uncommitted transactions aren't cached.  
+ */
+#define JOURNAL_START    ((__u32 *) (INFO + 1))
+#define JOURNAL_END      ((__u32 *) (FSYS_BUF + FSYS_BUFLEN))
+
+#ifdef __amd64
+#define BSF "bsfq"
+#else
+#define BSF "bsfl"
+#endif
+static __inline__ unsigned long
+grub_log2 (unsigned long word)
+{
+  __asm__ (BSF " %1,%0"
+	   : "=r" (word)
+	   : "r" (word));
+  return word;
+}
+#define log2 grub_log2
+
+static __inline__ int
+is_power_of_two (unsigned long word)
+{
+  return (word & -word) == word;
+}
+
+static int 
+journal_read (fsi_file_t *ffi, int block, int len, char *buffer) 
+{
+  return devread (ffi, (INFO->journal_block + block) << INFO->blocksize_shift, 
+		  0, len, buffer);
+}
+
+/* Read a block from ReiserFS file system, taking the journal into
+ * account.  If the block nr is in the journal, the block from the
+ * journal taken.  
+ */
+static int
+block_read (fsi_file_t *ffi, int blockNr, int start, int len, char *buffer)
+{
+  int transactions = INFO->journal_transactions;
+  int desc_block = INFO->journal_first_desc;
+  int journal_mask = INFO->journal_block_count - 1;
+  int translatedNr = blockNr;
+  __u32 *journal_table = JOURNAL_START;
+  while (transactions-- > 0) 
+    {
+      int i = 0;
+      int j_len;
+      if (*journal_table != 0xffffffff)
+	{
+	  /* Search for the blockNr in cached journal */
+	  j_len = *journal_table++;
+	  while (i++ < j_len)
+	    {
+	      if (*journal_table++ == blockNr)
+		{
+		  journal_table += j_len - i;
+		  goto found;
+		}
+	    }
+	}
+      else
+	{
+	  /* This is the end of cached journal marker.  The remaining
+	   * transactions are still on disk.
+	   */
+	  struct reiserfs_journal_desc   desc;
+	  struct reiserfs_journal_commit commit;
+
+	  if (! journal_read (ffi, desc_block, sizeof (desc), (char *) &desc))
+	    return 0;
+
+	  j_len = desc.j_len;
+	  while (i < j_len && i < JOURNAL_TRANS_HALF)
+	    if (desc.j_realblock[i++] == blockNr)
+	      goto found;
+	  
+	  if (j_len >= JOURNAL_TRANS_HALF)
+	    {
+	      int commit_block = (desc_block + 1 + j_len) & journal_mask;
+	      if (! journal_read (ffi, commit_block, 
+				  sizeof (commit), (char *) &commit))
+		return 0;
+	      while (i < j_len)
+		if (commit.j_realblock[i++ - JOURNAL_TRANS_HALF] == blockNr)
+		  goto found;
+	    }
+	}
+      goto not_found;
+      
+    found:
+      translatedNr = INFO->journal_block + ((desc_block + i) & journal_mask);
+#ifdef REISERDEBUG
+      printf ("block_read: block %d is mapped to journal block %d.\n", 
+	      blockNr, translatedNr - INFO->journal_block);
+#endif
+      /* We must continue the search, as this block may be overwritten
+       * in later transactions.
+       */
+    not_found:
+      desc_block = (desc_block + 2 + j_len) & journal_mask;
+    }
+  return devread (ffi, translatedNr << INFO->blocksize_shift, start, len, buffer);
+}
+
+/* Init the journal data structure.  We try to cache as much as
+ * possible in the JOURNAL_START-JOURNAL_END space, but if it is full
+ * we can still read the rest from the disk on demand.
+ *
+ * The first number of valid transactions and the descriptor block of the
+ * first valid transaction are held in INFO.  The transactions are all 
+ * adjacent, but we must take care of the journal wrap around. 
+ */
+static int
+journal_init (fsi_file_t *ffi)
+{
+  unsigned int block_count = INFO->journal_block_count;
+  unsigned int desc_block;
+  unsigned int commit_block;
+  unsigned int next_trans_id;
+  struct reiserfs_journal_header header;
+  struct reiserfs_journal_desc   desc;
+  struct reiserfs_journal_commit commit;
+  __u32 *journal_table = JOURNAL_START;
+
+  journal_read (ffi, block_count, sizeof (header), (char *) &header);
+  desc_block = header.j_first_unflushed_offset;
+  if (desc_block >= block_count)
+    return 0;
+
+  INFO->journal_first_desc = desc_block;
+  next_trans_id = header.j_last_flush_trans_id + 1;
+
+#ifdef REISERDEBUG
+  printf ("journal_init: last flushed %d\n", 
+	  header.j_last_flush_trans_id);
+#endif
+
+  while (1) 
+    {
+      journal_read (ffi, desc_block, sizeof (desc), (char *) &desc);
+      if (substring (JOURNAL_DESC_MAGIC, desc.j_magic)
+	  || desc.j_trans_id != next_trans_id
+	  || desc.j_mount_id != header.j_mount_id)
+	/* no more valid transactions */
+	break;
+      
+      commit_block = (desc_block + desc.j_len + 1) & (block_count - 1);
+      journal_read (ffi, commit_block, sizeof (commit), (char *) &commit);
+      if (desc.j_trans_id != commit.j_trans_id
+	  || desc.j_len != commit.j_len)
+	/* no more valid transactions */
+	break;
+      
+#ifdef REISERDEBUG
+      printf ("Found valid transaction %d/%d at %d.\n", 
+	      desc.j_trans_id, desc.j_mount_id, desc_block);
+#endif
+
+      next_trans_id++;
+      if (journal_table < JOURNAL_END)
+	{
+	  if ((journal_table + 1 + desc.j_len) >= JOURNAL_END)
+	    {
+	      /* The table is almost full; mark the end of the cached
+	       * journal.*/
+	      *journal_table = 0xffffffff;
+	      journal_table = JOURNAL_END;
+	    }
+	  else
+	    {
+	      int i;
+	      /* Cache the length and the realblock numbers in the table.
+	       * The block number of descriptor can easily be computed.
+	       * and need not to be stored here.
+	       */
+	      *journal_table++ = desc.j_len;
+	      for (i = 0; i < desc.j_len && i < JOURNAL_TRANS_HALF; i++)
+		{
+		  *journal_table++ = desc.j_realblock[i];
+#ifdef REISERDEBUG
+		  printf ("block %d is in journal %d.\n", 
+			  desc.j_realblock[i], desc_block);
+#endif
+		}
+	      for (     ; i < desc.j_len; i++)
+		{
+		  *journal_table++ = commit.j_realblock[i-JOURNAL_TRANS_HALF];
+#ifdef REISERDEBUG
+		  printf ("block %d is in journal %d.\n", 
+			  commit.j_realblock[i-JOURNAL_TRANS_HALF], 
+			  desc_block);
+#endif
+		}
+	    }
+	}
+      desc_block = (commit_block + 1) & (block_count - 1);
+    }
+#ifdef REISERDEBUG
+  printf ("Transaction %d/%d at %d isn't valid.\n", 
+	  desc.j_trans_id, desc.j_mount_id, desc_block);
+#endif
+
+  INFO->journal_transactions
+    = next_trans_id - header.j_last_flush_trans_id - 1;
+  return errnum == 0;
+}
+
+/* check filesystem types and read superblock into memory buffer */
+int
+reiserfs_mount (fsi_file_t *ffi)
+{
+  struct reiserfs_super_block super;
+  int superblock = REISERFS_DISK_OFFSET_IN_BYTES >> SECTOR_BITS;
+
+  if (/*part_length < superblock + (sizeof (super) >> SECTOR_BITS)
+      || */ !devread (ffi, superblock, 0, sizeof (struct reiserfs_super_block), 
+		(char *) &super)
+      || (substring (REISER3FS_SUPER_MAGIC_STRING, super.s_magic) > 0
+	  && substring (REISER2FS_SUPER_MAGIC_STRING, super.s_magic) > 0
+	  && substring (REISERFS_SUPER_MAGIC_STRING, super.s_magic) > 0)
+      || (/* check that this is not a copy inside the journal log */
+	  super.s_journal_block * super.s_blocksize
+	  <= REISERFS_DISK_OFFSET_IN_BYTES))
+    {
+      /* Try old super block position */
+      superblock = REISERFS_OLD_DISK_OFFSET_IN_BYTES >> SECTOR_BITS;
+      if (/*part_length < superblock + (sizeof (super) >> SECTOR_BITS)
+	|| */ ! devread (ffi, superblock, 0, sizeof (struct reiserfs_super_block), 
+			(char *) &super))
+	return 0;
+
+      if (substring (REISER3FS_SUPER_MAGIC_STRING, super.s_magic) > 0
+	  && substring (REISER2FS_SUPER_MAGIC_STRING, super.s_magic) > 0
+	  && substring (REISERFS_SUPER_MAGIC_STRING, super.s_magic) > 0)
+	{
+	  /* pre journaling super block ? */
+	  if (substring (REISERFS_SUPER_MAGIC_STRING, 
+			 (char*) ((char *) &super + 20)) > 0)
+	    return 0;
+	  
+	  super.s_blocksize = REISERFS_OLD_BLOCKSIZE;
+	  super.s_journal_block = 0;
+	  super.s_version = 0;
+	}
+    }
+
+  /* check the version number.  */
+  if (super.s_version > REISERFS_MAX_SUPPORTED_VERSION)
+    return 0;
+  
+  INFO->version = super.s_version;
+  INFO->blocksize = super.s_blocksize;
+  INFO->fullblocksize_shift = log2 (super.s_blocksize);
+  INFO->blocksize_shift = INFO->fullblocksize_shift - SECTOR_BITS;
+  INFO->cached_slots = 
+    (FSYSREISER_CACHE_SIZE >> INFO->fullblocksize_shift) - 1;
+
+#ifdef REISERDEBUG
+  printf ("reiserfs_mount: version=%d, blocksize=%d\n", 
+	  INFO->version, INFO->blocksize);
+#endif /* REISERDEBUG */
+
+  /* Clear node cache. */
+  memset (INFO->blocks, 0, sizeof (INFO->blocks));
+
+  if (super.s_blocksize < FSYSREISER_MIN_BLOCKSIZE
+      || super.s_blocksize > FSYSREISER_MAX_BLOCKSIZE
+      || (SECTOR_SIZE << INFO->blocksize_shift) != super.s_blocksize)
+    return 0;
+
+  /* Initialize journal code.  If something fails we end with zero
+   * journal_transactions, so we don't access the journal at all.  
+   */
+  INFO->journal_transactions = 0;
+  if (super.s_journal_block != 0 && super.s_journal_dev == 0)
+    {
+      INFO->journal_block = super.s_journal_block;
+      INFO->journal_block_count = super.s_journal_size;
+      if (is_power_of_two (INFO->journal_block_count))
+	journal_init (ffi);
+
+      /* Read in super block again, maybe it is in the journal */
+      block_read (ffi, superblock >> INFO->blocksize_shift, 
+		  0, sizeof (struct reiserfs_super_block), (char *) &super);
+    }
+
+  if (! block_read (ffi, super.s_root_block, 0, INFO->blocksize, (char*) ROOT))
+    return 0;
+  
+  INFO->tree_depth = BLOCKHEAD (ROOT)->blk_level;
+  
+#ifdef REISERDEBUG
+  printf ("root read_in: block=%d, depth=%d\n", 
+	  super.s_root_block, INFO->tree_depth);
+#endif /* REISERDEBUG */
+
+  if (INFO->tree_depth >= MAX_HEIGHT)
+    return 0;
+  if (INFO->tree_depth == DISK_LEAF_NODE_LEVEL)
+    {
+      /* There is only one node in the whole filesystem, 
+       * which is simultanously leaf and root */
+      memcpy (LEAF, ROOT, INFO->blocksize);
+    }
+  return 1;
+}
+
+/***************** TREE ACCESSING METHODS *****************************/
+
+/* I assume you are familiar with the ReiserFS tree, if not go to
+ * http://www.namesys.com/content_table.html
+ *
+ * My tree node cache is organized as following
+ *   0   ROOT node
+ *   1   LEAF node  (if the ROOT is also a LEAF it is copied here
+ *   2-n other nodes on current path from bottom to top.  
+ *       if there is not enough space in the cache, the top most are
+ *       omitted.
+ *
+ * I have only two methods to find a key in the tree:
+ *   search_stat(dir_id, objectid) searches for the stat entry (always
+ *       the first entry) of an object.
+ *   next_key() gets the next key in tree order.
+ *
+ * This means, that I can only sequential reads of files are
+ * efficient, but this really doesn't hurt for grub.  
+ */
+
+/* Read in the node at the current path and depth into the node cache.
+ * You must set INFO->blocks[depth] before.
+ */
+static char *
+read_tree_node (fsi_file_t *ffi, unsigned int blockNr, int depth)
+{
+  char* cache = CACHE(depth);
+  int num_cached = INFO->cached_slots;
+  if (depth < num_cached)
+    {
+      /* This is the cached part of the path.  Check if same block is
+       * needed.  
+       */
+      if (blockNr == INFO->blocks[depth])
+	return cache;
+    }
+  else
+    cache = CACHE(num_cached);
+
+#ifdef REISERDEBUG
+  printf ("  next read_in: block=%d (depth=%d)\n",
+	  blockNr, depth);
+#endif /* REISERDEBUG */
+  if (! block_read (ffi, blockNr, 0, INFO->blocksize, cache))
+    return 0;
+  /* Make sure it has the right node level */
+  if (BLOCKHEAD (cache)->blk_level != depth)
+    {
+      errnum = ERR_FSYS_CORRUPT;
+      return 0;
+    }
+
+  INFO->blocks[depth] = blockNr;
+  return cache;
+}
+
+/* Get the next key, i.e. the key following the last retrieved key in
+ * tree order.  INFO->current_ih and 
+ * INFO->current_info are adapted accordingly.  */
+static int
+next_key (fsi_file_t *ffi)
+{
+  int depth;
+  struct item_head *ih = INFO->current_ih + 1;
+  char *cache;
+  
+#ifdef REISERDEBUG
+  printf ("next_key:\n  old ih: key %d:%d:%d:%d version:%d\n", 
+	  INFO->current_ih->ih_key.k_dir_id, 
+	  INFO->current_ih->ih_key.k_objectid, 
+	  INFO->current_ih->ih_key.u.v1.k_offset,
+	  INFO->current_ih->ih_key.u.v1.k_uniqueness,
+	  INFO->current_ih->ih_version);
+#endif /* REISERDEBUG */
+  
+  if (ih == &ITEMHEAD[BLOCKHEAD (LEAF)->blk_nr_item])
+    {
+      depth = DISK_LEAF_NODE_LEVEL;
+      /* The last item, was the last in the leaf node.  
+       * Read in the next block 
+       */
+      do
+	{
+	  if (depth == INFO->tree_depth)
+	    {
+	      /* There are no more keys at all.
+	       * Return a dummy item with MAX_KEY */
+	      ih = (struct item_head *) &BLOCKHEAD (LEAF)->blk_right_delim_key;
+	      goto found;
+	    }
+	  depth++;
+#ifdef REISERDEBUG
+	  printf ("  depth=%d, i=%d\n", depth, INFO->next_key_nr[depth]);
+#endif /* REISERDEBUG */
+	}
+      while (INFO->next_key_nr[depth] == 0);
+      
+      if (depth == INFO->tree_depth)
+	cache = ROOT;
+      else if (depth <= INFO->cached_slots)
+	cache = CACHE (depth);
+      else 
+	{
+	  cache = read_tree_node (ffi, INFO->blocks[depth], depth);
+	  if (! cache)
+	    return 0;
+	}
+      
+      do
+	{
+	  int nr_item = BLOCKHEAD (cache)->blk_nr_item;
+	  int key_nr = INFO->next_key_nr[depth]++;
+#ifdef REISERDEBUG
+	  printf ("  depth=%d, i=%d/%d\n", depth, key_nr, nr_item);
+#endif /* REISERDEBUG */
+	  if (key_nr == nr_item)
+	    /* This is the last item in this block, set the next_key_nr to 0 */
+	    INFO->next_key_nr[depth] = 0;
+
+	  cache = read_tree_node (ffi, DC (cache)[key_nr].dc_block_number, --depth);
+	  if (! cache)
+	    return 0;
+	}
+      while (depth > DISK_LEAF_NODE_LEVEL);
+      
+      ih = ITEMHEAD;
+    }
+ found:
+  INFO->current_ih   = ih;
+  INFO->current_item = &LEAF[ih->ih_item_location];
+#ifdef REISERDEBUG
+  printf ("  new ih: key %d:%d:%d:%d version:%d\n", 
+	  INFO->current_ih->ih_key.k_dir_id, 
+	  INFO->current_ih->ih_key.k_objectid, 
+	  INFO->current_ih->ih_key.u.v1.k_offset,
+	  INFO->current_ih->ih_key.u.v1.k_uniqueness,
+	  INFO->current_ih->ih_version);
+#endif /* REISERDEBUG */
+  return 1;
+}
+
+/* preconditions: reiserfs_mount already executed, therefore 
+ *   INFO block is valid
+ * returns: 0 if error (errnum is set), 
+ *   nonzero iff we were able to find the key successfully.
+ * postconditions: on a nonzero return, the current_ih and 
+ *   current_item fields describe the key that equals the
+ *   searched key.  INFO->next_key contains the next key after
+ *   the searched key.
+ * side effects: messes around with the cache.
+ */
+static int
+search_stat (fsi_file_t *ffi, __u32 dir_id, __u32 objectid) 
+{
+  char *cache;
+  int depth;
+  int nr_item;
+  int i;
+  struct item_head *ih;
+#ifdef REISERDEBUG
+  printf ("search_stat:\n  key %d:%d:0:0\n", dir_id, objectid);
+#endif /* REISERDEBUG */
+  
+  depth = INFO->tree_depth;
+  cache = ROOT;
+  
+  while (depth > DISK_LEAF_NODE_LEVEL)
+    {
+      struct key *key;
+      nr_item = BLOCKHEAD (cache)->blk_nr_item;
+      
+      key = KEY (cache);
+      
+      for (i = 0; i < nr_item; i++) 
+	{
+	  if (key->k_dir_id > dir_id
+	      || (key->k_dir_id == dir_id 
+		  && (key->k_objectid > objectid
+		      || (key->k_objectid == objectid
+			  && (key->u.v1.k_offset
+			      | key->u.v1.k_uniqueness) > 0))))
+	    break;
+	  key++;
+	}
+      
+#ifdef REISERDEBUG
+      printf ("  depth=%d, i=%d/%d\n", depth, i, nr_item);
+#endif /* REISERDEBUG */
+      INFO->next_key_nr[depth] = (i == nr_item) ? 0 : i+1;
+      cache = read_tree_node (ffi, DC (cache)[i].dc_block_number, --depth);
+      if (! cache)
+	return 0;
+    }
+  
+  /* cache == LEAF */
+  nr_item = BLOCKHEAD (LEAF)->blk_nr_item;
+  ih = ITEMHEAD;
+  for (i = 0; i < nr_item; i++) 
+    {
+      if (ih->ih_key.k_dir_id == dir_id 
+	  && ih->ih_key.k_objectid == objectid
+	  && ih->ih_key.u.v1.k_offset == 0
+	  && ih->ih_key.u.v1.k_uniqueness == 0)
+	{
+#ifdef REISERDEBUG
+	  printf ("  depth=%d, i=%d/%d\n", depth, i, nr_item);
+#endif /* REISERDEBUG */
+	  INFO->current_ih   = ih;
+	  INFO->current_item = &LEAF[ih->ih_item_location];
+	  return 1;
+	}
+      ih++;
+    }
+  errnum = ERR_FSYS_CORRUPT;
+  return 0;
+}
+
+int
+reiserfs_read (fsi_file_t *ffi, char *buf, int len)
+{
+  unsigned int blocksize;
+  unsigned int offset;
+  unsigned int to_read;
+  char *prev_buf = buf;
+  
+#ifdef REISERDEBUG
+  printf ("reiserfs_read: filepos=%d len=%d, offset=%x:%x\n",
+	  filepos, len, (__u64) IH_KEY_OFFSET (INFO->current_ih) - 1);
+#endif /* REISERDEBUG */
+  
+  if (INFO->current_ih->ih_key.k_objectid != INFO->fileinfo.k_objectid
+      || IH_KEY_OFFSET (INFO->current_ih) > filepos + 1)
+    {
+      search_stat (ffi, INFO->fileinfo.k_dir_id, INFO->fileinfo.k_objectid);
+      goto get_next_key;
+    }
+  
+  while (! errnum)
+    {
+      if (INFO->current_ih->ih_key.k_objectid != INFO->fileinfo.k_objectid)
+	break;
+      
+      offset = filepos - IH_KEY_OFFSET (INFO->current_ih) + 1;
+      blocksize = INFO->current_ih->ih_item_len;
+      
+#ifdef REISERDEBUG
+      printf ("  loop: filepos=%d len=%d, offset=%d blocksize=%d\n",
+	      filepos, len, offset, blocksize);
+#endif /* REISERDEBUG */
+      
+      if (IH_KEY_ISTYPE(INFO->current_ih, TYPE_DIRECT)
+	  && offset < blocksize)
+	{
+#ifdef REISERDEBUG
+	  printf ("direct_read: offset=%d, blocksize=%d\n",
+		  offset, blocksize);
+#endif /* REISERDEBUG */
+	  to_read = blocksize - offset;
+	  if (to_read > len)
+	    to_read = len;
+	  
+	  if (disk_read_hook != NULL)
+	    {
+	      disk_read_func = disk_read_hook;
+	      
+	      block_read (ffi, INFO->blocks[DISK_LEAF_NODE_LEVEL],
+			  (INFO->current_item - LEAF + offset), to_read, buf);
+	      
+	      disk_read_func = NULL;
+	    }
+	  else
+	    memcpy (buf, INFO->current_item + offset, to_read);
+	  goto update_buf_len;
+	}
+      else if (IH_KEY_ISTYPE(INFO->current_ih, TYPE_INDIRECT))
+	{
+	  blocksize = (blocksize >> 2) << INFO->fullblocksize_shift;
+#ifdef REISERDEBUG
+	  printf ("indirect_read: offset=%d, blocksize=%d\n",
+		  offset, blocksize);
+#endif /* REISERDEBUG */
+	  
+	  while (offset < blocksize)
+	    {
+	      __u32 blocknr = ((__u32 *) INFO->current_item)
+		[offset >> INFO->fullblocksize_shift];
+	      int blk_offset = offset & (INFO->blocksize-1);
+	      
+	      to_read = INFO->blocksize - blk_offset;
+	      if (to_read > len)
+		to_read = len;
+	      
+	      disk_read_func = disk_read_hook;
+	      
+	      /* Journal is only for meta data.  Data blocks can be read
+	       * directly without using block_read
+	       */
+	      devread (ffi, blocknr << INFO->blocksize_shift,
+		       blk_offset, to_read, buf);
+	      
+	      disk_read_func = NULL;
+	    update_buf_len:
+	      len -= to_read;
+	      buf += to_read;
+	      offset += to_read;
+	      filepos += to_read;
+	      if (len == 0)
+		goto done;
+	    }
+	}
+    get_next_key:
+      next_key (ffi);
+    }
+ done:
+  return errnum ? 0 : buf - prev_buf;
+}
+
+
+/* preconditions: reiserfs_mount already executed, therefore 
+ *   INFO block is valid
+ * returns: 0 if error, nonzero iff we were able to find the file successfully
+ * postconditions: on a nonzero return, INFO->fileinfo contains the info
+ *   of the file we were trying to look up, filepos is 0 and filemax is 
+ *   the size of the file.
+ */
+int
+reiserfs_dir (fsi_file_t *ffi, char *dirname)
+{
+  struct reiserfs_de_head *de_head;
+  char *rest, ch;
+  __u32 dir_id, objectid, parent_dir_id = 0, parent_objectid = 0;
+#ifndef STAGE1_5
+  int do_possibilities = 0;
+#endif /* ! STAGE1_5 */
+  char linkbuf[PATH_MAX];	/* buffer for following symbolic links */
+  int link_count = 0;
+  int mode;
+
+  dir_id = REISERFS_ROOT_PARENT_OBJECTID;
+  objectid = REISERFS_ROOT_OBJECTID;
+  
+  while (1)
+    {
+#ifdef REISERDEBUG
+      printf ("dirname=%s\n", dirname);
+#endif /* REISERDEBUG */
+      
+      /* Search for the stat info first. */
+      if (! search_stat (ffi, dir_id, objectid))
+	return 0;
+      
+#ifdef REISERDEBUG
+      printf ("sd_mode=%x sd_size=%d\n", 
+	      ((struct stat_data *) INFO->current_item)->sd_mode,
+	      ((struct stat_data *) INFO->current_item)->sd_size);
+#endif /* REISERDEBUG */
+      
+      mode = ((struct stat_data *) INFO->current_item)->sd_mode;
+
+      /* If we've got a symbolic link, then chase it. */
+      if (S_ISLNK (mode))
+	{
+	  int len;
+	  if (++link_count > MAX_LINK_COUNT)
+	    {
+	      errnum = ERR_SYMLINK_LOOP;
+	      return 0;
+	    }
+
+	  /* Get the symlink size. */
+	  filemax = ((struct stat_data *) INFO->current_item)->sd_size;
+
+	  /* Find out how long our remaining name is. */
+	  len = 0;
+	  while (dirname[len] && !isspace (dirname[len]))
+	    len++;
+
+	  if (filemax + len > sizeof (linkbuf) - 1)
+	    {
+	      errnum = ERR_FILELENGTH;
+	      return 0;
+	    }
+ 	  
+	  /* Copy the remaining name to the end of the symlink data.
+	     Note that DIRNAME and LINKBUF may overlap! */
+	  grub_memmove (linkbuf + filemax, dirname, len+1);
+
+	  INFO->fileinfo.k_dir_id = dir_id;
+	  INFO->fileinfo.k_objectid = objectid;
+  	  filepos = 0;
+	  if (! next_key (ffi)
+	      || reiserfs_read (ffi, linkbuf, filemax) != filemax)
+	    {
+	      if (! errnum)
+		errnum = ERR_FSYS_CORRUPT;
+	      return 0;
+	    }
+
+#ifdef REISERDEBUG
+	  printf ("symlink=%s\n", linkbuf);
+#endif /* REISERDEBUG */
+
+	  dirname = linkbuf;
+	  if (*dirname == '/')
+	    {
+	      /* It's an absolute link, so look it up in root. */
+	      dir_id = REISERFS_ROOT_PARENT_OBJECTID;
+	      objectid = REISERFS_ROOT_OBJECTID;
+	    }
+	  else
+	    {
+	      /* Relative, so look it up in our parent directory. */
+	      dir_id   = parent_dir_id;
+	      objectid = parent_objectid;
+	    }
+
+	  /* Now lookup the new name. */
+	  continue;
+	}
+
+      /* if we have a real file (and we're not just printing possibilities),
+	 then this is where we want to exit */
+      
+      if (! *dirname || isspace (*dirname))
+	{
+	  if (! S_ISREG (mode))
+	    {
+	      errnum = ERR_BAD_FILETYPE;
+	      return 0;
+	    }
+	  
+	  filepos = 0;
+	  filemax = ((struct stat_data *) INFO->current_item)->sd_size;
+	  
+	  /* If this is a new stat data and size is > 4GB set filemax to 
+	   * maximum
+	   */
+	  if (INFO->current_ih->ih_version == ITEM_VERSION_2
+	      && ((struct stat_data *) INFO->current_item)->sd_size_hi > 0)
+	    filemax = 0xffffffff;
+	  
+	  INFO->fileinfo.k_dir_id = dir_id;
+	  INFO->fileinfo.k_objectid = objectid;
+	  return next_key (ffi);
+	}
+      
+      /* continue with the file/directory name interpretation */
+      while (*dirname == '/')
+	dirname++;
+      if (! S_ISDIR (mode))
+	{
+	  errnum = ERR_BAD_FILETYPE;
+	  return 0;
+	}
+      for (rest = dirname; (ch = *rest) && ! isspace (ch) && ch != '/'; rest++);
+      *rest = 0;
+      
+# ifndef STAGE1_5
+      if (print_possibilities && ch != '/')
+	do_possibilities = 1;
+# endif /* ! STAGE1_5 */
+      
+      while (1)
+	{
+	  char *name_end;
+	  int num_entries;
+	  
+	  if (! next_key (ffi))
+	    return 0;
+#ifdef REISERDEBUG
+	  printf ("ih: key %d:%d:%d:%d version:%d\n", 
+		  INFO->current_ih->ih_key.k_dir_id, 
+		  INFO->current_ih->ih_key.k_objectid, 
+		  INFO->current_ih->ih_key.u.v1.k_offset,
+		  INFO->current_ih->ih_key.u.v1.k_uniqueness,
+		  INFO->current_ih->ih_version);
+#endif /* REISERDEBUG */
+	  
+	  if (INFO->current_ih->ih_key.k_objectid != objectid)
+	    break;
+	  
+	  name_end = INFO->current_item + INFO->current_ih->ih_item_len;
+	  de_head = (struct reiserfs_de_head *) INFO->current_item;
+	  num_entries = INFO->current_ih->u.ih_entry_count;
+	  while (num_entries > 0)
+	    {
+	      char *filename = INFO->current_item + de_head->deh_location;
+	      char  tmp = *name_end;
+	      if ((de_head->deh_state & DEH_Visible))
+		{
+		  int cmp;
+		  /* Directory names in ReiserFS are not null
+		   * terminated.  We write a temporary 0 behind it.
+		   * NOTE: that this may overwrite the first block in
+		   * the tree cache.  That doesn't hurt as long as we
+		   * don't call next_key () in between.  
+		   */
+		  *name_end = 0;
+		  cmp = substring (dirname, filename);
+		  *name_end = tmp;
+# ifndef STAGE1_5
+		  if (do_possibilities)
+		    {
+		      if (cmp <= 0)
+			{
+			  if (print_possibilities > 0)
+			    print_possibilities = -print_possibilities;
+			  *name_end = 0;
+			  print_a_completion (filename);
+			  *name_end = tmp;
+			}
+		    }
+		  else
+# endif /* ! STAGE1_5 */
+		    if (cmp == 0)
+		      goto found;
+		}
+	      /* The beginning of this name marks the end of the next name.
+	       */
+	      name_end = filename;
+	      de_head++;
+	      num_entries--;
+	    }
+	}
+      
+# ifndef STAGE1_5
+      if (print_possibilities < 0)
+	return 1;
+# endif /* ! STAGE1_5 */
+      
+      errnum = ERR_FILE_NOT_FOUND;
+      *rest = ch;
+      return 0;
+      
+    found:
+      
+      *rest = ch;
+      dirname = rest;
+
+      parent_dir_id = dir_id;
+      parent_objectid = objectid;
+      dir_id = de_head->deh_dir_id;
+      objectid = de_head->deh_objectid;
+    }
+}
+
+int
+reiserfs_embed (fsi_file_t *ffi, int *start_sector, int needed_sectors)
+{
+  struct reiserfs_super_block super;
+  int num_sectors;
+  
+  if (! devread (ffi, REISERFS_DISK_OFFSET_IN_BYTES >> SECTOR_BITS, 0, 
+		 sizeof (struct reiserfs_super_block), (char *) &super))
+    return 0;
+  
+  *start_sector = 1; /* reserve first sector for stage1 */
+  if ((substring (REISERFS_SUPER_MAGIC_STRING, super.s_magic) <= 0
+       || substring (REISER2FS_SUPER_MAGIC_STRING, super.s_magic) <= 0
+       || substring (REISER3FS_SUPER_MAGIC_STRING, super.s_magic) <= 0)
+      && (/* check that this is not a super block copy inside
+	   * the journal log */
+	  super.s_journal_block * super.s_blocksize 
+	  > REISERFS_DISK_OFFSET_IN_BYTES))
+    num_sectors = (REISERFS_DISK_OFFSET_IN_BYTES >> SECTOR_BITS) - 1;
+  else
+    num_sectors = (REISERFS_OLD_DISK_OFFSET_IN_BYTES >> SECTOR_BITS) - 1;
+  
+  return (needed_sectors <= num_sectors);
+}
+
+fsi_plugin_ops_t *
+fsi_init_plugin(int version, fsi_plugin_t *fp, const char **name)
+{
+	static fsig_plugin_ops_t ops = {
+		FSIMAGE_PLUGIN_VERSION,
+		.fpo_mount = reiserfs_mount,
+		.fpo_dir = reiserfs_dir,
+		.fpo_read = reiserfs_read
+	};
+
+	*name = "reiserfs";
+	return (fsig_init(fp, &ops));
+}