/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 1999, 2001, 2003  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.
 */

#ifdef FSYS_EXT2FS

#include "shared.h"
#include "filesys.h"

static int mapblock1, mapblock2;

/* sizes are always in bytes, BLOCK values are always in DEV_BSIZE (sectors) */
#define DEV_BSIZE 512

/* include/linux/fs.h */
#define BLOCK_SIZE 1024         /* initial block size for superblock read */
/* made up, defaults to 1 but can be passed via mount_opts */
#define WHICH_SUPER 1
/* kind of from fs/ext2/super.c */
#define SBLOCK (WHICH_SUPER * BLOCK_SIZE / DEV_BSIZE)   /* = 2 */

/* 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;

/*
 * Constants relative to the data blocks, from ext2_fs.h
 */
#define EXT2_NDIR_BLOCKS                12
#define EXT2_IND_BLOCK                  EXT2_NDIR_BLOCKS
#define EXT2_DIND_BLOCK                 (EXT2_IND_BLOCK + 1)
#define EXT2_TIND_BLOCK                 (EXT2_DIND_BLOCK + 1)
#define EXT2_N_BLOCKS                   (EXT2_TIND_BLOCK + 1)

/* include/linux/ext2_fs.h */
struct ext2_super_block
  {
    __u32 s_inodes_count;       /* Inodes count */
    __u32 s_blocks_count;       /* Blocks count */
    __u32 s_r_blocks_count;     /* Reserved blocks count */
    __u32 s_free_blocks_count;  /* Free blocks count */
    __u32 s_free_inodes_count;  /* Free inodes count */
    __u32 s_first_data_block;   /* First Data Block */
    __u32 s_log_block_size;     /* Block size */
    __s32 s_log_frag_size;      /* Fragment size */
    __u32 s_blocks_per_group;   /* # Blocks per group */
    __u32 s_frags_per_group;    /* # Fragments per group */
    __u32 s_inodes_per_group;   /* # Inodes per group */
    __u32 s_mtime;              /* Mount time */
    __u32 s_wtime;              /* Write time */
    __u16 s_mnt_count;          /* Mount count */
    __s16 s_max_mnt_count;      /* Maximal mount count */
    __u16 s_magic;              /* Magic signature */
    __u16 s_state;              /* File system state */
    __u16 s_errors;             /* Behaviour when detecting errors */
    __u16 s_pad;
    __u32 s_lastcheck;          /* time of last check */
    __u32 s_checkinterval;      /* max. time between checks */
    __u32 s_creator_os;         /* OS */
    __u32 s_rev_level;          /* Revision level */
    __u16 s_def_resuid;         /* Default uid for reserved blocks */
    __u16 s_def_resgid;         /* Default gid for reserved blocks */
   /*
    * These fields are for EXT2_DYNAMIC_REV superblocks only.
    *
    * Note: the difference between the compatible feature set and
    * the incompatible feature set is that if there is a bit set
    * in the incompatible feature set that the kernel doesn't
    * know about, it should refuse to mount the filesystem.
    *
    * e2fsck's requirements are more strict; if it doesn't know
    * about a feature in either the compatible or incompatible
    * feature set, it must abort and not try to meddle with
    * things it doesn't understand...
    */
   __u32 s_first_ino;           /* First non-reserved inode */
   __u16 s_inode_size;          /* size of inode structure */
   __u16 s_block_group_nr;      /* block group # of this superblock */
   __u32 s_feature_compat;      /* compatible feature set */
   __u32 s_feature_incompat;    /* incompatible feature set */
   __u32 s_feature_ro_compat;   /* readonly-compatible feature set */
   __u8  s_uuid[16];            /* 128-bit uuid for volume */
   char  s_volume_name[16];     /* volume name */
   char  s_last_mounted[64];    /* directory where last mounted */
   __u32 s_algorithm_usage_bitmap; /* For compression */
   /*
    * Performance hints.  Directory preallocation should only
    * happen if the EXT2_FEATURE_COMPAT_DIR_PREALLOC flag is on.
    */
   __u8  s_prealloc_blocks;     /* Nr of blocks to try to preallocate*/
   __u8  s_prealloc_dir_blocks; /* Nr to preallocate for dirs */
   __u16 s_reserved_gdt_blocks;/* Per group table for online growth */
   /*
    * Journaling support valid if EXT2_FEATURE_COMPAT_HAS_JOURNAL set.
    */
   __u8 s_journal_uuid[16];     /* uuid of journal superblock */
   __u32 s_journal_inum;        /* inode number of journal file */
   __u32 s_journal_dev; /* device number of journal file */
   __u32 s_last_orphan; /* start of list of inodes to delete */
   __u32 s_hash_seed[4];        /* HTREE hash seed */
   __u8  s_def_hash_version;    /* Default hash version to use */
   __u8  s_jnl_backup_type;     /* Default type of journal backup */
   __u16 s_reserved_word_pad;
   __u32 s_default_mount_opts;
   __u32 s_first_meta_bg;       /* First metablock group */
   __u32 s_mkfs_time;           /* When the filesystem was created */
   __u32 s_jnl_blocks[17];      /* Backup of the journal inode */
   __u32 s_reserved[172];       /* Padding to the end of the block */
  };

struct ext2_group_desc
  {
    __u32 bg_block_bitmap;      /* Blocks bitmap block */
    __u32 bg_inode_bitmap;      /* Inodes bitmap block */
    __u32 bg_inode_table;       /* Inodes table block */
    __u16 bg_free_blocks_count; /* Free blocks count */
    __u16 bg_free_inodes_count; /* Free inodes count */
    __u16 bg_used_dirs_count;   /* Directories count */
    __u16 bg_pad;
    __u32 bg_reserved[3];
  };

struct ext2_inode
  {
    __u16 i_mode;               /* File mode */
    __u16 i_uid;                /* Owner Uid */
    __u32 i_size;               /* 4: Size in bytes */
    __u32 i_atime;              /* Access time */
    __u32 i_ctime;              /* 12: Creation time */
    __u32 i_mtime;              /* Modification time */
    __u32 i_dtime;              /* 20: Deletion Time */
    __u16 i_gid;                /* Group Id */
    __u16 i_links_count;        /* 24: Links count */
    __u32 i_blocks;             /* Blocks count */
    __u32 i_flags;              /* 32: File flags */
    union
      {
        struct
          {
            __u32 l_i_reserved1;
          }
        linux1;
        struct
          {
            __u32 h_i_translator;
          }
        hurd1;
        struct
          {
            __u32 m_i_reserved1;
          }
        masix1;
      }
    osd1;                       /* OS dependent 1 */
    __u32 i_block[EXT2_N_BLOCKS];       /* 40: Pointers to blocks */
    __u32 i_version;            /* File version (for NFS) */
    __u32 i_file_acl;           /* File ACL */
    __u32 i_dir_acl;            /* Directory ACL */
    __u32 i_faddr;              /* Fragment address */
    union
      {
        struct
          {
            __u8 l_i_frag;      /* Fragment number */
            __u8 l_i_fsize;     /* Fragment size */
            __u16 i_pad1;
            __u32 l_i_reserved2[2];
          }
        linux2;
        struct
          {
            __u8 h_i_frag;      /* Fragment number */
            __u8 h_i_fsize;     /* Fragment size */
            __u16 h_i_mode_high;
            __u16 h_i_uid_high;
            __u16 h_i_gid_high;
            __u32 h_i_author;
          }
        hurd2;
        struct
          {
            __u8 m_i_frag;      /* Fragment number */
            __u8 m_i_fsize;     /* Fragment size */
            __u16 m_pad1;
            __u32 m_i_reserved2[2];
          }
        masix2;
      }
    osd2;                       /* OS dependent 2 */
  };

/* linux/limits.h */
#define NAME_MAX         255    /* # chars in a file name */

/* linux/posix_type.h */
typedef long linux_off_t;

/* linux/ext2fs.h */
#define EXT2_NAME_LEN 255
struct ext2_dir_entry
  {
    __u32 inode;                /* Inode number */
    __u16 rec_len;              /* Directory entry length */
    __u8 name_len;              /* Name length */
    __u8 file_type;
    char name[EXT2_NAME_LEN];   /* File name */
  };

/* linux/ext2fs.h */
/*
 * EXT2_DIR_PAD defines the directory entries boundaries
 *
 * NOTE: It must be a multiple of 4
 */
#define EXT2_DIR_PAD                    4
#define EXT2_DIR_ROUND                  (EXT2_DIR_PAD - 1)
#define EXT2_DIR_REC_LEN(name_len)      (((name_len) + 8 + EXT2_DIR_ROUND) & \
                                         ~EXT2_DIR_ROUND)


/* ext2/super.c */
#define log2(n) ffz(~(n))

#define EXT2_SUPER_MAGIC      0xEF53    /* include/linux/ext2_fs.h */
#define EXT2_ROOT_INO              2    /* include/linux/ext2_fs.h */
#define PATH_MAX                1024    /* include/linux/limits.h */
#define MAX_LINK_COUNT             5    /* number of symbolic links to follow */

/* made up, these are pointers into FSYS_BUF */
/* read once, always stays there: */
#define SUPERBLOCK \
    ((struct ext2_super_block *)(FSYS_BUF))
#define GROUP_DESC \
    ((struct ext2_group_desc *) \
     ((int)SUPERBLOCK + sizeof(struct ext2_super_block)))
#define INODE \
    ((struct ext2_inode *)((int)GROUP_DESC + EXT2_BLOCK_SIZE(SUPERBLOCK)))
#define DATABLOCK1 \
    ((int)((int)INODE + sizeof(struct ext2_inode)))
#define DATABLOCK2 \
    ((int)((int)DATABLOCK1 + EXT2_BLOCK_SIZE(SUPERBLOCK)))

/* linux/ext2_fs.h */
#define EXT2_ADDR_PER_BLOCK(s)          (EXT2_BLOCK_SIZE(s) / sizeof (__u32))
#define EXT2_ADDR_PER_BLOCK_BITS(s)             (log2(EXT2_ADDR_PER_BLOCK(s)))

#define EXT2_INODE_SIZE(s)              (SUPERBLOCK->s_inode_size)
#define EXT2_INODES_PER_BLOCK(s)        (EXT2_BLOCK_SIZE(s)/EXT2_INODE_SIZE(s))

/* linux/ext2_fs.h */
#define EXT2_BLOCK_SIZE_BITS(s)        ((s)->s_log_block_size + 10)
/* kind of from ext2/super.c */
#define EXT2_BLOCK_SIZE(s)      (1 << EXT2_BLOCK_SIZE_BITS(s))
/* linux/ext2fs.h */
#define EXT2_DESC_PER_BLOCK(s) \
     (EXT2_BLOCK_SIZE(s) / sizeof (struct ext2_group_desc))
/* linux/stat.h */
#define S_IFMT  00170000
#define S_IFLNK  0120000
#define S_IFREG  0100000
#define S_IFDIR  0040000
#define S_ISLNK(m)      (((m) & S_IFMT) == S_IFLNK)
#define S_ISREG(m)      (((m) & S_IFMT) == S_IFREG)
#define S_ISDIR(m)      (((m) & S_IFMT) == S_IFDIR)

/* include/asm-i386/bitops.h */
/*
 * ffz = Find First Zero in word. Undefined if no zero exists,
 * so code should check against ~0UL first..
 */
static __inline__ unsigned long
ffz (unsigned long word)
{
  __asm__ ("bsfl %1,%0"
:          "=r" (word)
:          "r" (~word));
  return word;
}

/* check filesystem types and read superblock into memory buffer */
int
ext2fs_mount (void)
{
  int retval = 1;

  if ((((current_drive & 0x80) || (current_slice != 0))
       && (current_slice != PC_SLICE_TYPE_EXT2FS)
       && (current_slice != PC_SLICE_TYPE_LINUX_RAID)
       && (! IS_PC_SLICE_TYPE_BSD_WITH_FS (current_slice, FS_EXT2FS))
       && (! IS_PC_SLICE_TYPE_BSD_WITH_FS (current_slice, FS_OTHER)))
      || part_length < (SBLOCK + (sizeof (struct ext2_super_block) / DEV_BSIZE))
      || !devread (SBLOCK, 0, sizeof (struct ext2_super_block),
                   (char *) SUPERBLOCK)
      || SUPERBLOCK->s_magic != EXT2_SUPER_MAGIC)
      retval = 0;

  return retval;
}

/* Takes a file system block number and reads it into BUFFER. */
static int
ext2_rdfsb (int fsblock, int buffer)
{
#ifdef E2DEBUG
  printf ("fsblock %d buffer %d\n", fsblock, buffer);
#endif /* E2DEBUG */
  return devread (fsblock * (EXT2_BLOCK_SIZE (SUPERBLOCK) / DEV_BSIZE), 0,
                  EXT2_BLOCK_SIZE (SUPERBLOCK), (char *) buffer);
}

/* from
  ext2/inode.c:ext2_bmap()
*/
/* Maps LOGICAL_BLOCK (the file offset divided by the blocksize) into
   a physical block (the location in the file system) via an inode. */
static int
ext2fs_block_map (int logical_block)
{

#ifdef E2DEBUG
  unsigned char *i;
  for (i = (unsigned char *) INODE;
       i < ((unsigned char *) INODE + sizeof (struct ext2_inode));
       i++)
    {
      printf ("%c", "0123456789abcdef"[*i >> 4]);
      printf ("%c", "0123456789abcdef"[*i % 16]);
      if (!((i + 1 - (unsigned char *) INODE) % 16))
        {
          printf ("\n");
        }
      else
        {
          printf (" ");
        }
    }
  printf ("logical block %d\n", logical_block);
#endif /* E2DEBUG */

  /* if it is directly pointed to by the inode, return that physical addr */
  if (logical_block < EXT2_NDIR_BLOCKS)
    {
#ifdef E2DEBUG
      printf ("returning %d\n", (unsigned char *) (INODE->i_block[logical_block]));
      printf ("returning %d\n", INODE->i_block[logical_block]);
#endif /* E2DEBUG */
      return INODE->i_block[logical_block];
    }
  /* else */
  logical_block -= EXT2_NDIR_BLOCKS;
  /* try the indirect block */
  if (logical_block < EXT2_ADDR_PER_BLOCK (SUPERBLOCK))
    {
      if (mapblock1 != 1
          && !ext2_rdfsb (INODE->i_block[EXT2_IND_BLOCK], DATABLOCK1))
        {
          errnum = ERR_FSYS_CORRUPT;
          return -1;
        }
      mapblock1 = 1;
      return ((__u32 *) DATABLOCK1)[logical_block];
    }
  /* else */
  logical_block -= EXT2_ADDR_PER_BLOCK (SUPERBLOCK);
  /* now try the double indirect block */
  if (logical_block < (1 << (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK) * 2)))
    {
      int bnum;
      if (mapblock1 != 2
          && !ext2_rdfsb (INODE->i_block[EXT2_DIND_BLOCK], DATABLOCK1))
        {
          errnum = ERR_FSYS_CORRUPT;
          return -1;
        }
      mapblock1 = 2;
      if ((bnum = (((__u32 *) DATABLOCK1)
                   [logical_block >> EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK)]))
          != mapblock2
          && !ext2_rdfsb (bnum, DATABLOCK2))
        {
          errnum = ERR_FSYS_CORRUPT;
          return -1;
        }
      mapblock2 = bnum;
      return ((__u32 *) DATABLOCK2)
        [logical_block & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)];
    }
  /* else */
  mapblock2 = -1;
  logical_block -= (1 << (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK) * 2));
  if (mapblock1 != 3
      && !ext2_rdfsb (INODE->i_block[EXT2_TIND_BLOCK], DATABLOCK1))
    {
      errnum = ERR_FSYS_CORRUPT;
      return -1;
    }
  mapblock1 = 3;
  if (!ext2_rdfsb (((__u32 *) DATABLOCK1)
                   [logical_block >> (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK)
                                      * 2)],
                   DATABLOCK2))
    {
      errnum = ERR_FSYS_CORRUPT;
      return -1;
    }
  if (!ext2_rdfsb (((__u32 *) DATABLOCK2)
                   [(logical_block >> EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK))
                    & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)],
                   DATABLOCK2))
    {
      errnum = ERR_FSYS_CORRUPT;
      return -1;
    }
  return ((__u32 *) DATABLOCK2)
    [logical_block & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)];
}

/* preconditions: all preconds of ext2fs_block_map */
int
ext2fs_read (char *buf, int len)
{
  int logical_block;
  int offset;
  int map;
  int ret = 0;
  int size = 0;

#ifdef E2DEBUG
  static char hexdigit[] = "0123456789abcdef";
  unsigned char *i;
  for (i = (unsigned char *) INODE;
       i < ((unsigned char *) INODE + sizeof (struct ext2_inode));
       i++)
    {
      printf ("%c", hexdigit[*i >> 4]);
      printf ("%c", hexdigit[*i % 16]);
      if (!((i + 1 - (unsigned char *) INODE) % 16))
        {
          printf ("\n");
        }
      else
        {
          printf (" ");
        }
    }
#endif /* E2DEBUG */
  while (len > 0)
    {
      /* find the (logical) block component of our location */
      logical_block = filepos >> EXT2_BLOCK_SIZE_BITS (SUPERBLOCK);
      offset = filepos & (EXT2_BLOCK_SIZE (SUPERBLOCK) - 1);
      map = ext2fs_block_map (logical_block);
#ifdef E2DEBUG
      printf ("map=%d\n", map);
#endif /* E2DEBUG */
      if (map < 0)
        break;

      size = EXT2_BLOCK_SIZE (SUPERBLOCK);
      size -= offset;
      if (size > len)
        size = len;

      if (map == 0) {
        memset ((char *) buf, 0, size);
      } else {
        disk_read_func = disk_read_hook;

        devread (map * (EXT2_BLOCK_SIZE (SUPERBLOCK) / DEV_BSIZE),
                 offset, size, buf);

        disk_read_func = NULL;
      }

      buf += size;
      len -= size;
      filepos += size;
      ret += size;
    }

  if (errnum)
    ret = 0;

  return ret;
}


/* Based on:
   def_blk_fops points to
   blkdev_open, which calls (I think):
   sys_open()
   do_open()
   open_namei()
   dir_namei() which accesses current->fs->root
     fs->root was set during original mount:
     (something)... which calls (I think):
     ext2_read_super()
     iget()
     __iget()
     read_inode()
     ext2_read_inode()
       uses desc_per_block_bits, which is set in ext2_read_super()
       also uses group descriptors loaded during ext2_read_super()
   lookup()
   ext2_lookup()
   ext2_find_entry()
   ext2_getblk()

*/

static inline
int ext2_is_fast_symlink (void)
{
  int ea_blocks;
  ea_blocks = INODE->i_file_acl ? EXT2_BLOCK_SIZE (SUPERBLOCK) / DEV_BSIZE : 0;
  return INODE->i_blocks == ea_blocks;
}

/* preconditions: ext2fs_mount already executed, therefore supblk in buffer
 *   known as SUPERBLOCK
 * returns: 0 if error, nonzero iff we were able to find the file successfully
 * postconditions: on a nonzero return, buffer known as INODE contains the
 *   inode of the file we were trying to look up
 * side effects: messes up GROUP_DESC buffer area
 */
int
ext2fs_dir (char *dirname)
{
  int current_ino = EXT2_ROOT_INO;      /* start at the root */
  int updir_ino = current_ino;  /* the parent of the current directory */
  int group_id;                 /* which group the inode is in */
  int group_desc;               /* fs pointer to that group */
  int desc;                     /* index within that group */
  int ino_blk;                  /* fs pointer of the inode's information */
  int str_chk = 0;              /* used to hold the results of a string compare */
  struct ext2_group_desc *gdp;
  struct ext2_inode *raw_inode; /* inode info corresponding to current_ino */

  char linkbuf[PATH_MAX];       /* buffer for following symbolic links */
  int link_count = 0;

  char *rest;
  char ch;                      /* temp char holder */

  int off;                      /* offset within block of directory entry (off mod blocksize) */
  int loc;                      /* location within a directory */
  int blk;                      /* which data blk within dir entry (off div blocksize) */
  long map;                     /* fs pointer of a particular block from dir entry */
  struct ext2_dir_entry *dp;    /* pointer to directory entry */
#ifdef E2DEBUG
  unsigned char *i;
#endif  /* E2DEBUG */

  /* loop invariants:
     current_ino = inode to lookup
     dirname = pointer to filename component we are cur looking up within
     the directory known pointed to by current_ino (if any)
   */

  while (1)
    {
#ifdef E2DEBUG
      printf ("inode %d\n", current_ino);
      printf ("dirname=%s\n", dirname);
#endif /* E2DEBUG */

      /* look up an inode */
      group_id = (current_ino - 1) / (SUPERBLOCK->s_inodes_per_group);
      group_desc = group_id >> log2 (EXT2_DESC_PER_BLOCK (SUPERBLOCK));
      desc = group_id & (EXT2_DESC_PER_BLOCK (SUPERBLOCK) - 1);
#ifdef E2DEBUG
      printf ("ipg=%d, dpb=%d\n", SUPERBLOCK->s_inodes_per_group,
              EXT2_DESC_PER_BLOCK (SUPERBLOCK));
      printf ("group_id=%d group_desc=%d desc=%d\n", group_id, group_desc, desc);
#endif /* E2DEBUG */
      if (!ext2_rdfsb (
                        (WHICH_SUPER + group_desc + SUPERBLOCK->s_first_data_block),
                        (int) GROUP_DESC))
        {
          return 0;
        }
      gdp = GROUP_DESC;
      ino_blk = gdp[desc].bg_inode_table +
        (((current_ino - 1) % (SUPERBLOCK->s_inodes_per_group))
         >> log2 (EXT2_INODES_PER_BLOCK (SUPERBLOCK)));
#ifdef E2DEBUG
      printf ("inode table fsblock=%d\n", ino_blk);
#endif /* E2DEBUG */
      if (!ext2_rdfsb (ino_blk, (int) INODE))
        {
          return 0;
        }

      /* reset indirect blocks! */
      mapblock2 = mapblock1 = -1;

      raw_inode = (struct ext2_inode *)((char *)INODE +
        ((current_ino - 1) & (EXT2_INODES_PER_BLOCK (SUPERBLOCK) - 1)) *
        EXT2_INODE_SIZE (SUPERBLOCK));

#ifdef E2DEBUG
      printf ("ipb=%d, sizeof(inode)=%d\n",
              EXT2_INODES_PER_BLOCK (SUPERBLOCK), EXT2_INODE_SIZE (SUPERBLOCK));
      printf ("inode=%x, raw_inode=%x\n", INODE, raw_inode);
      printf ("offset into inode table block=%d\n", (int) raw_inode - (int) INODE);
      for (i = (unsigned char *) INODE; i <= (unsigned char *) raw_inode;
           i++)
        {
          printf ("%c", "0123456789abcdef"[*i >> 4]);
          printf ("%c", "0123456789abcdef"[*i % 16]);
          if (!((i + 1 - (unsigned char *) INODE) % 16))
            {
              printf ("\n");
            }
          else
            {
              printf (" ");
            }
        }
      printf ("first word=%x\n", *((int *) raw_inode));
#endif /* E2DEBUG */

      /* copy inode to fixed location */
      memmove ((void *) INODE, (void *) raw_inode, sizeof (struct ext2_inode));

#ifdef E2DEBUG
      printf ("first word=%x\n", *((int *) INODE));
#endif /* E2DEBUG */

      /* If we've got a symbolic link, then chase it. */
      if (S_ISLNK (INODE->i_mode))
        {
          int len;
          if (++link_count > MAX_LINK_COUNT)
            {
              errnum = ERR_SYMLINK_LOOP;
              return 0;
            }

          /* Find out how long our remaining name is. */
          len = 0;
          while (dirname[len] && !isspace (dirname[len]))
            len++;

          /* Get the symlink size. */
          filemax = (INODE->i_size);
          if (filemax + len > sizeof (linkbuf) - 2)
            {
              errnum = ERR_FILELENGTH;
              return 0;
            }

          if (len)
            {
              /* Copy the remaining name to the end of the symlink data.
                 Note that DIRNAME and LINKBUF may overlap! */
              memmove (linkbuf + filemax, dirname, len);
            }
          linkbuf[filemax + len] = '\0';

          /* Read the symlink data. */
          if (! ext2_is_fast_symlink ())
            {
              /* Read the necessary blocks, and reset the file pointer. */
              len = grub_read (linkbuf, filemax);
              filepos = 0;
              if (!len)
                return 0;
            }
          else
            {
              /* Copy the data directly from the inode. */
              len = filemax;
              memmove (linkbuf, (char *) INODE->i_block, len);
            }

#ifdef E2DEBUG
          printf ("symlink=%s\n", linkbuf);
#endif

          dirname = linkbuf;
          if (*dirname == '/')
            {
              /* It's an absolute link, so look it up in root. */
              current_ino = EXT2_ROOT_INO;
              updir_ino = current_ino;
            }
          else
            {
              /* Relative, so look it up in our parent directory. */
              current_ino = updir_ino;
            }

          /* Try again using the new name. */
          continue;
        }

      /* if end of filename, INODE points to the file's inode */
      if (!*dirname || isspace (*dirname))
        {
          if (!S_ISREG (INODE->i_mode))
            {
              errnum = ERR_BAD_FILETYPE;
              return 0;
            }

          filemax = (INODE->i_size);
          return 1;
        }

      /* else we have to traverse a directory */
      updir_ino = current_ino;

      /* skip over slashes */
      while (*dirname == '/')
        dirname++;

      /* if this isn't a directory of sufficient size to hold our file, abort */
      if (!(INODE->i_size) || !S_ISDIR (INODE->i_mode))
        {
          errnum = ERR_BAD_FILETYPE;
          return 0;
        }

      /* skip to next slash or end of filename (space) */
      for (rest = dirname; (ch = *rest) && !isspace (ch) && ch != '/';
           rest++);

      /* look through this directory and find the next filename component */
      /* invariant: rest points to slash after the next filename component */
      *rest = 0;
      loc = 0;

      do
        {

#ifdef E2DEBUG
          printf ("dirname=%s, rest=%s, loc=%d\n", dirname, rest, loc);
#endif /* E2DEBUG */

          /* if our location/byte offset into the directory exceeds the size,
             give up */
          if (loc >= INODE->i_size)
            {
              if (print_possibilities < 0)
                {
# if 0
                  putchar ('\n');
# endif
                }
              else
                {
                  errnum = ERR_FILE_NOT_FOUND;
                  *rest = ch;
                }
              return (print_possibilities < 0);
            }

          /* else, find the (logical) block component of our location */
          blk = loc >> EXT2_BLOCK_SIZE_BITS (SUPERBLOCK);

          /* we know which logical block of the directory entry we are looking
             for, now we have to translate that to the physical (fs) block on
             the disk */
          map = ext2fs_block_map (blk);
#ifdef E2DEBUG
          printf ("fs block=%d\n", map);
#endif /* E2DEBUG */
          mapblock2 = -1;
          if ((map < 0) || !ext2_rdfsb (map, DATABLOCK2))
            {
              errnum = ERR_FSYS_CORRUPT;
              *rest = ch;
              return 0;
            }
          off = loc & (EXT2_BLOCK_SIZE (SUPERBLOCK) - 1);
          dp = (struct ext2_dir_entry *) (DATABLOCK2 + off);
          /* advance loc prematurely to next on-disk directory entry  */
          loc += dp->rec_len;

          /* NOTE: ext2fs filenames are NOT null-terminated */

#ifdef E2DEBUG
          printf ("directory entry ino=%d\n", dp->inode);
          if (dp->inode)
            printf ("entry=%s\n", dp->name);
#endif /* E2DEBUG */

          if (dp->inode)
            {
              int saved_c = dp->name[dp->name_len];

              dp->name[dp->name_len] = 0;
              str_chk = substring (dirname, dp->name);

# ifndef STAGE1_5
              if (print_possibilities && ch != '/'
                  && (!*dirname || str_chk <= 0))
                {
                  if (print_possibilities > 0)
                    print_possibilities = -print_possibilities;
                  print_a_completion (dp->name);
                }
# endif

              dp->name[dp->name_len] = saved_c;
            }

        }
      while (!dp->inode || (str_chk || (print_possibilities && ch != '/')));

      current_ino = dp->inode;
      *(dirname = rest) = ch;
    }
  /* never get here */
}

#endif /* FSYS_EXT2_FS */