/* ext2.c - Second Extended filesystem */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2003, 2004 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.
*/
/* Magic value used to identify an ext2 filesystem. */
#define EXT2_MAGIC 0xEF53
/* Amount of indirect blocks in an inode. */
#define INDIRECT_BLOCKS 12
/* Maximum lenght of a pathname. */
#define EXT2_PATH_MAX 4096
/* Maximum nesting of symlinks, used to prevent a loop. */
#define EXT2_MAX_SYMLINKCNT 8
/* Filetype used in directory entry. */
#define FILETYPE_DIRECTORY 2
#define FILETYPE_SYMLINK 7
/* Filetype information as used in inodes. */
#define FILETYPE_INO_MASK 0170000
#define FILETYPE_INO_DIRECTORY 0040000
#define FILETYPE_INO_SYMLINK 0120000
#include <grub/err.h>
#include <grub/file.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/disk.h>
#include <grub/dl.h>
#include <grub/types.h>
/* Log2 size of ext2 block in 512 blocks. */
#define LOG2_EXT2_BLOCK_SIZE(data) \
(grub_le_to_cpu32 (data->sblock.log2_block_size) + 1)
/* Log2 size of ext2 block in bytes. */
#define LOG2_BLOCK_SIZE(data) \
(grub_le_to_cpu32 (data->sblock.log2_block_size) + 10)
/* The size of an ext2 block in bytes. */
#define EXT2_BLOCK_SIZE(data) (1 << LOG2_BLOCK_SIZE(data))
/* The ext2 superblock. */
struct grub_ext_sblock
{
grub_uint32_t total_inodes;
grub_uint32_t total_blocks;
grub_uint32_t reserved_blocks;
grub_uint32_t free_blocks;
grub_uint32_t free_inodes;
grub_uint32_t first_data_block;
grub_uint32_t log2_block_size;
grub_uint32_t log2_fragment_size;
grub_uint32_t blocks_per_group;
grub_uint32_t fragments_per_group;
grub_uint32_t inodes_per_group;
grub_uint32_t mtime;
grub_uint32_t utime;
grub_uint16_t mnt_count;
grub_uint16_t max_mnt_count;
grub_uint16_t magic;
grub_uint16_t fs_state;
grub_uint16_t error_handling;
grub_uint16_t minor_revision_level;
grub_uint32_t lastcheck;
grub_uint32_t checkinterval;
grub_uint32_t creator_os;
grub_uint32_t revision_level;
grub_uint16_t uid_reserved;
grub_uint16_t gid_reserved;
grub_uint32_t first_inode;
grub_uint16_t inode_size;
grub_uint16_t block_group_number;
grub_uint32_t feature_compatibility;
grub_uint32_t feature_incompat;
grub_uint32_t feature_ro_compat;
grub_uint32_t unique_id[4];
char volume_name[16];
char last_mounted_on[64];
grub_uint32_t compression_info;
};
/* The ext2 blockgroup. */
struct ext2_block_group
{
grub_uint32_t block_id;
grub_uint32_t inode_id;
grub_uint32_t inode_table_id;
grub_uint16_t free_blocks;
grub_uint16_t free_inodes;
grub_uint16_t pad;
grub_uint32_t reserved[3];
};
/* The ext2 inode. */
struct grub_ext2_inode
{
grub_uint16_t mode;
grub_uint16_t uid;
grub_uint32_t size;
grub_uint32_t atime;
grub_uint32_t ctime;
grub_uint32_t mtime;
grub_uint32_t dtime;
grub_uint16_t gid;
grub_uint16_t nlinks;
grub_uint32_t blockcnt; /* Blocks of 512 bytes!! */
grub_uint32_t flags;
grub_uint32_t osd1;
union
{
struct datablocks
{
grub_uint32_t dir_blocks[INDIRECT_BLOCKS];
grub_uint32_t indir_block;
grub_uint32_t double_indir_block;
grub_uint32_t tripple_indir_block;
} blocks;
char symlink[60];
};
grub_uint32_t version;
grub_uint32_t acl;
grub_uint32_t dir_acl;
grub_uint32_t fragment_addr;
grub_uint32_t osd2[3];
};
/* The header of an ext2 directory entry. */
struct ext2_dirent
{
grub_uint32_t inode;
grub_uint16_t direntlen;
grub_uint8_t namelen;
grub_uint8_t filetype;
};
/* Information about a "mounted" ext2 filesystem. */
struct grub_ext2_data
{
struct grub_ext_sblock sblock;
grub_disk_t disk;
struct grub_ext2_inode inode;
};
#ifndef GRUB_UTIL
static grub_dl_t my_mod;
#endif
/* Read into BLKGRP the blockgroup descriptor of blockgroup GROUP of
the mounted filesystem DATA. */
inline static grub_err_t
grub_ext2_blockgroup (struct grub_ext2_data *data, int group,
struct ext2_block_group *blkgrp)
{
return grub_disk_read (data->disk,
((grub_le_to_cpu32 (data->sblock.first_data_block) + 1)
<< LOG2_EXT2_BLOCK_SIZE (data)),
group * sizeof (struct ext2_block_group),
sizeof (struct ext2_block_group), (char *) blkgrp);
}
/* Return in BLOCK the on disk block number of block FILEBLOCK in the
opened file descibed by DATA. If this block is not stored on disk
in case of a sparse file return 0. */
static grub_err_t
grub_ext2_get_file_block (struct grub_ext2_data *data,
int fileblock, int *block)
{
int blknr;
struct grub_ext2_inode *inode = &data->inode;
/* Direct blocks. */
if (fileblock < INDIRECT_BLOCKS)
blknr = grub_le_to_cpu32 (inode->blocks.dir_blocks[fileblock]);
/* Indirect. */
else if (fileblock < INDIRECT_BLOCKS + EXT2_BLOCK_SIZE (data) / 4)
{
grub_uint32_t indir[EXT2_BLOCK_SIZE (data) / 4];
if (grub_disk_read (data->disk,
grub_le_to_cpu32 (inode->blocks.indir_block)
<< LOG2_EXT2_BLOCK_SIZE (data),
0, EXT2_BLOCK_SIZE (data), (char *) indir))
return grub_errno;
blknr = grub_le_to_cpu32 (indir[fileblock - INDIRECT_BLOCKS]);
}
/* Double indirect. */
else if (fileblock < INDIRECT_BLOCKS + EXT2_BLOCK_SIZE (data) / 4
* (EXT2_BLOCK_SIZE (data) / 4 + 1))
{
unsigned int perblock = EXT2_BLOCK_SIZE (data) / 4;
unsigned int rblock = fileblock - (INDIRECT_BLOCKS
+ EXT2_BLOCK_SIZE (data) / 4);
grub_uint32_t indir[EXT2_BLOCK_SIZE (data) / 4];
if (grub_disk_read (data->disk,
grub_le_to_cpu32 (inode->blocks.double_indir_block)
<< LOG2_EXT2_BLOCK_SIZE (data),
0, EXT2_BLOCK_SIZE (data), (char *) indir))
return grub_errno;
if (grub_disk_read (data->disk,
grub_le_to_cpu32 (indir[rblock / perblock])
<< LOG2_EXT2_BLOCK_SIZE (data),
0, EXT2_BLOCK_SIZE (data), (char *) indir))
return grub_errno;
blknr = grub_le_to_cpu32 (indir[rblock % perblock]);
}
/* Tripple indirect. */
else
{
grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
"ext2fs doesn't support tripple indirect blocks");
return grub_errno;
}
*block = blknr;
return 0;
}
/* Read LEN bytes from the file described by DATA starting with byte
POS. Return the amount of read bytes in READ. */
static grub_ssize_t
grub_ext2_read_file (struct grub_ext2_data *data,
void (*read_hook) (unsigned long sector,
unsigned offset, unsigned length),
int pos, unsigned int len, char *buf)
{
int i;
int blockcnt;
/* Adjust len so it we can't read past the end of the file. */
if (len > grub_le_to_cpu32 (data->inode.size))
len = grub_le_to_cpu32 (data->inode.size);
blockcnt = ((len + pos)
+ EXT2_BLOCK_SIZE (data) - 1) / EXT2_BLOCK_SIZE (data);
for (i = pos / EXT2_BLOCK_SIZE (data); i < blockcnt; i++)
{
int blknr;
int blockoff = pos % EXT2_BLOCK_SIZE (data);
int blockend = EXT2_BLOCK_SIZE (data);
int skipfirst = 0;
grub_ext2_get_file_block (data, i, &blknr);
if (grub_errno)
return -1;
blknr = blknr << LOG2_EXT2_BLOCK_SIZE (data);
/* Last block. */
if (i == blockcnt - 1)
{
blockend = (len + pos) % EXT2_BLOCK_SIZE (data);
/* The last portion is exactly EXT2_BLOCK_SIZE (data). */
if (!blockend)
blockend = EXT2_BLOCK_SIZE (data);
}
/* First block. */
if (i == pos / EXT2_BLOCK_SIZE (data))
{
skipfirst = blockoff;
blockend -= skipfirst;
}
/* If the block number is 0 this block is not stored on disk but
is zero filled instead. */
if (blknr)
{
data->disk->read_hook = read_hook;
grub_disk_read (data->disk, blknr, skipfirst,
blockend, buf);
data->disk->read_hook = 0;
if (grub_errno)
return -1;
}
else
grub_memset (buf, EXT2_BLOCK_SIZE (data) - skipfirst, 0);
buf += EXT2_BLOCK_SIZE (data) - skipfirst;
}
return len;
}
/* Read the inode INO for the file described by DATA into INODE. */
static grub_err_t
grub_ext2_read_inode (struct grub_ext2_data *data,
int ino, struct grub_ext2_inode *inode)
{
struct ext2_block_group blkgrp;
struct grub_ext_sblock *sblock = &data->sblock;
int inodes_per_block;
unsigned int blkno;
unsigned int blkoff;
/* It is easier to calculate if the first inode is 0. */
ino--;
grub_ext2_blockgroup (data, ino / grub_le_to_cpu32 (sblock->inodes_per_group),
&blkgrp);
if (grub_errno)
return grub_errno;
inodes_per_block = EXT2_BLOCK_SIZE (data) / 128;
blkno = (ino % grub_le_to_cpu32 (sblock->inodes_per_group))
/ inodes_per_block;
blkoff = (ino % grub_le_to_cpu32 (sblock->inodes_per_group))
% inodes_per_block;
/* Read the inode. */
if (grub_disk_read (data->disk,
((grub_le_to_cpu32 (blkgrp.inode_table_id) + blkno)
<< LOG2_EXT2_BLOCK_SIZE (data)),
sizeof (struct grub_ext2_inode) * blkoff,
sizeof (struct grub_ext2_inode), (char *) inode))
return grub_errno;
return 0;
}
static struct grub_ext2_data *
grub_ext2_mount (grub_disk_t disk)
{
struct grub_ext2_data *data;
data = grub_malloc (sizeof (struct grub_ext2_data));
if (!data)
return 0;
/* Read the superblock. */
grub_disk_read (disk, 1 * 2, 0, sizeof (struct grub_ext_sblock),
(char *) &data->sblock);
if (grub_errno)
goto fail;
/* Make sure this is an ext2 filesystem. */
if (grub_le_to_cpu16 (data->sblock.magic) != EXT2_MAGIC)
goto fail;
data->disk = disk;
return data;
fail:
grub_error (GRUB_ERR_BAD_FS, "not an ext2 filesystem");
grub_free (data);
return 0;
}
/* Find the file with the pathname PATH on the filesystem described by
DATA. Return its inode number in INO. */
static grub_err_t
grub_ext2_find_file (struct grub_ext2_data *data, const char *path, int *ino)
{
int blocksize = EXT2_BLOCK_SIZE (data)
<< grub_le_to_cpu32 (data->sblock.log2_block_size);
struct grub_ext2_inode *inode = &data->inode;
int currinode = 2;
int symlinkcnt = 0;
char fpath[EXT2_PATH_MAX];
char *name = fpath;
grub_strncpy (fpath, path, EXT2_PATH_MAX);
if (!name || name[0] != '/')
{
grub_error (GRUB_ERR_BAD_FILENAME, "bad filename");
return grub_errno;
}
/* Skip the first slash. */
name++;
if (!*name)
{
*ino = 2;
return 0;
}
/* Remove trailing "/". */
if (name[grub_strlen (name) - 1] =='/')
name[grub_strlen (name) - 1] = '\0';
while (*name)
{
unsigned int fpos = 0;
char *next;
int namesize;
/* Extract the actual part from the pathname. */
next = grub_strchr (name, '/');
if (next)
{
next[0] = '\0';
next++;
}
namesize = grub_strlen (name);
/* Open the file. */
grub_ext2_read_inode (data, currinode, inode);
if (grub_errno)
goto fail;
/* Search the file. */
while (fpos < grub_le_to_cpu32 (inode->size))
{
struct ext2_dirent dirent;
/* Read the directory entry. */
grub_ext2_read_file (data, 0, fpos, sizeof (struct ext2_dirent),
(char *) &dirent);
if (grub_errno)
goto fail;
if (dirent.namelen != 0)
{
char filename[dirent.namelen + 1];
/* Read the filename part of this directory entry. */
grub_ext2_read_file (data, 0, fpos
+ sizeof (struct ext2_dirent),
dirent.namelen, filename);
if (grub_errno)
goto fail;
filename[dirent.namelen] = '\0';
/* Check if the current directory entry described the
file we are looking for. */
if (dirent.namelen == namesize
&& !grub_strncmp (name, filename, namesize))
{
/* Stat the inode. */
grub_ext2_read_inode (data,
grub_le_to_cpu32 (dirent.inode),
inode);
/* If this is a symlink, follow it. */
if ((grub_le_to_cpu16 (data->inode.mode)
& FILETYPE_INO_MASK) == FILETYPE_INO_SYMLINK)
{
/* XXX: Use malloc instead? */
char symlink[blocksize];
if (++symlinkcnt == EXT2_MAX_SYMLINKCNT)
{
grub_error (GRUB_ERR_SYMLINK_LOOP,
"too deep nesting of symlinks");
goto fail;
}
/* If the filesize of the symlink is bigger than
60 the symlink is stored in a separate block,
otherwise it is stored in the inode. */
if (grub_le_to_cpu32 (inode->size) <= 60)
grub_strncpy (symlink,
inode->symlink,
grub_le_to_cpu32 (inode->size));
else
{
grub_ext2_read_file (data, 0, 0,
grub_le_to_cpu32 (inode->size),
symlink);
if (grub_errno)
goto fail;
}
symlink[grub_le_to_cpu32 (inode->size)] = '\0';
/* Check if the symlink is absolute or relative. */
if (symlink[0] == '/')
{
grub_strncpy (fpath, symlink + 1, EXT2_PATH_MAX);
name = fpath;
currinode = 2;
}
else
{
char *bak = 0;
if (next)
{
bak = grub_strdup (next);
if (!bak)
goto fail;
}
/* Relative symlink, construct the new path. */
grub_strcpy (fpath, symlink);
name = fpath;
if (next)
{
grub_strcat (name, "/");
grub_strcat (name, bak);
grub_free (bak);
}
}
fpos = 0;
break;
}
if (next)
{
currinode = grub_le_to_cpu32 (dirent.inode);
name = next;
if ((grub_le_to_cpu16 (data->inode.mode)
& FILETYPE_INO_MASK) != FILETYPE_INO_DIRECTORY)
{
grub_error (GRUB_ERR_BAD_FILE_TYPE,
"not a directory");
goto fail;
}
break;
}
else /* Found it! */
{
*ino = grub_le_to_cpu32 (dirent.inode);
return 0;
}
}
}
/* Move to next directory entry. */
fpos += grub_le_to_cpu16 (dirent.direntlen);
}
/* The complete directory was read and no matching file was
found. */
if (fpos >= grub_le_to_cpu32 (inode->size))
{
grub_error (GRUB_ERR_FILE_NOT_FOUND, "file not found");
goto fail;
}
}
fail:
return grub_errno;
}
/* Open a file named NAME and initialize FILE. */
static grub_err_t
grub_ext2_open (struct grub_file *file, const char *name)
{
struct grub_ext2_data *data;
int ino;
#ifndef GRUB_UTIL
grub_dl_ref (my_mod);
#endif
data = grub_ext2_mount (file->device->disk);
if (!data)
goto fail;
grub_ext2_find_file (data, name, &ino);
if (grub_errno)
goto fail;
grub_ext2_read_inode (data, ino, &data->inode);
if (grub_errno)
goto fail;
if (!(grub_le_to_cpu16 (data->inode.mode) & 0100000))
{
grub_error (GRUB_ERR_BAD_FILE_TYPE, "not a regular file");
goto fail;
}
file->size = grub_le_to_cpu32 (data->inode.size);
file->data = data;
file->offset = 0;
return 0;
fail:
grub_free (data);
#ifndef GRUB_UTIL
grub_dl_unref (my_mod);
#endif
return grub_errno;
}
static grub_err_t
grub_ext2_close (grub_file_t file)
{
grub_free (file->data);
#ifndef GRUB_UTIL
grub_dl_unref (my_mod);
#endif
return GRUB_ERR_NONE;
}
/* Read LEN bytes data from FILE into BUF. */
static grub_ssize_t
grub_ext2_read (grub_file_t file, char *buf, grub_ssize_t len)
{
struct grub_ext2_data *data =
(struct grub_ext2_data *) file->data;
return grub_ext2_read_file (data, file->read_hook, file->offset, len, buf);
}
static grub_err_t
grub_ext2_dir (grub_device_t device, const char *path,
int (*hook) (const char *filename, int dir))
{
struct grub_ext2_data *data = 0;;
int ino;
unsigned int fpos = 0;
#ifndef GRUB_UTIL
grub_dl_ref (my_mod);
#endif
data = grub_ext2_mount (device->disk);
if (!data)
goto fail;
grub_ext2_find_file (data, (char *) path, &ino);
if (grub_errno)
goto fail;
grub_ext2_read_inode (data, ino, &data->inode);
if (grub_errno)
goto fail;
if ((grub_le_to_cpu16 (data->inode.mode)
& FILETYPE_INO_MASK) != FILETYPE_INO_DIRECTORY)
{
grub_error (GRUB_ERR_BAD_FILE_TYPE, "not a directory");
goto fail;
}
/* Search the file. */
while (fpos < grub_le_to_cpu32 (data->inode.size))
{
struct ext2_dirent dirent;
grub_ext2_read_file (data, 0, fpos, sizeof (struct ext2_dirent),
(char *) &dirent);
if (grub_errno)
goto fail;
if (dirent.namelen != 0)
{
char filename[dirent.namelen + 1];
grub_ext2_read_file (data, 0, fpos + sizeof (struct ext2_dirent),
dirent.namelen, filename);
if (grub_errno)
goto fail;
filename[dirent.namelen] = '\0';
hook (filename, dirent.filetype == FILETYPE_DIRECTORY);
}
fpos += grub_le_to_cpu16 (dirent.direntlen);
}
fail:
grub_free (data);
#ifndef GRUB_UTIL
grub_dl_unref (my_mod);
#endif
return grub_errno;
}
static grub_err_t
grub_ext2_label (grub_device_t device, char **label)
{
struct grub_ext2_data *data;
grub_disk_t disk = device->disk;
#ifndef GRUB_UTIL
grub_dl_ref (my_mod);
#endif
data = grub_ext2_mount (disk);
if (data)
*label = grub_strndup (data->sblock.volume_name, 14);
else
*label = 0;
#ifndef GRUB_UTIL
grub_dl_unref (my_mod);
#endif
grub_free (data);
return grub_errno;
}
static struct grub_fs grub_ext2_fs =
{
.name = "ext2",
.dir = grub_ext2_dir,
.open = grub_ext2_open,
.read = grub_ext2_read,
.close = grub_ext2_close,
.label = grub_ext2_label,
.next = 0
};
#ifdef GRUB_UTIL
void
grub_ext2_init (void)
{
grub_fs_register (&grub_ext2_fs);
}
void
grub_ext2_fini (void)
{
grub_fs_unregister (&grub_ext2_fs);
}
#else /* ! GRUB_UTIL */
GRUB_MOD_INIT
{
grub_fs_register (&grub_ext2_fs);
my_mod = mod;
}
GRUB_MOD_FINI
{
grub_fs_unregister (&grub_ext2_fs);
}
#endif /* ! GRUB_UTIL */