vbatts/grub
1
0
Fork 0
Code Issues Pull requests Releases Wiki Activity
grub/grub-core/fs/ext2.c
Vladimir Serbinenko 5537a586e0 ext2: Ignore INCOMPAT_MMP. 
It's not really incompatible as long as driver never writes to FS.
2015-02-16 21:08:37 +01:00

1076 lines
29 KiB
C
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/* ext2.c - Second Extended filesystem */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2003,2004,2005,2007,2008,2009 Free Software Foundation, Inc.
*
* GRUB 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 3 of the License, or
* (at your option) any later version.
*
* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
/* Magic value used to identify an ext2 filesystem. */
#define EXT2_MAGIC 0xEF53
/* Amount of indirect blocks in an inode. */
#define INDIRECT_BLOCKS 12
/* The good old revision and the default inode size. */
#define EXT2_GOOD_OLD_REVISION 0
#define EXT2_GOOD_OLD_INODE_SIZE 128
/* Filetype used in directory entry. */
#define FILETYPE_UNKNOWN 0
#define FILETYPE_REG 1
#define FILETYPE_DIRECTORY 2
#define FILETYPE_SYMLINK 7
/* Filetype information as used in inodes. */
#define FILETYPE_INO_MASK 0170000
#define FILETYPE_INO_REG 0100000
#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>
#include <grub/fshelp.h>
GRUB_MOD_LICENSE ("GPLv3+");
/* 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) (1U << LOG2_BLOCK_SIZE (data))
/* The revision level. */
#define EXT2_REVISION(data) grub_le_to_cpu32 (data->sblock.revision_level)
/* The inode size. */
#define EXT2_INODE_SIZE(data) \
(data->sblock.revision_level \
== grub_cpu_to_le32_compile_time (EXT2_GOOD_OLD_REVISION) \
? EXT2_GOOD_OLD_INODE_SIZE \
: grub_le_to_cpu16 (data->sblock.inode_size))
/* Superblock filesystem feature flags (RW compatible)
* A filesystem with any of these enabled can be read and written by a driver
* that does not understand them without causing metadata/data corruption. */
#define EXT2_FEATURE_COMPAT_DIR_PREALLOC 0x0001
#define EXT2_FEATURE_COMPAT_IMAGIC_INODES 0x0002
#define EXT3_FEATURE_COMPAT_HAS_JOURNAL 0x0004
#define EXT2_FEATURE_COMPAT_EXT_ATTR 0x0008
#define EXT2_FEATURE_COMPAT_RESIZE_INODE 0x0010
#define EXT2_FEATURE_COMPAT_DIR_INDEX 0x0020
/* Superblock filesystem feature flags (RO compatible)
* A filesystem with any of these enabled can be safely read by a driver that
* does not understand them, but should not be written to, usually because
* additional metadata is required. */
#define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
#define EXT2_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
#define EXT2_FEATURE_RO_COMPAT_BTREE_DIR 0x0004
#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM 0x0010
#define EXT4_FEATURE_RO_COMPAT_DIR_NLINK 0x0020
#define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE 0x0040
/* Superblock filesystem feature flags (back-incompatible)
* A filesystem with any of these enabled should not be attempted to be read
* by a driver that does not understand them, since they usually indicate
* metadata format changes that might confuse the reader. */
#define EXT2_FEATURE_INCOMPAT_COMPRESSION 0x0001
#define EXT2_FEATURE_INCOMPAT_FILETYPE 0x0002
#define EXT3_FEATURE_INCOMPAT_RECOVER 0x0004 /* Needs recovery */
#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008 /* Volume is journal device */
#define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
#define EXT4_FEATURE_INCOMPAT_EXTENTS 0x0040 /* Extents used */
#define EXT4_FEATURE_INCOMPAT_64BIT 0x0080
#define EXT4_FEATURE_INCOMPAT_MMP 0x0100
#define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
/* The set of back-incompatible features this driver DOES support. Add (OR)
* flags here as the related features are implemented into the driver. */
#define EXT2_DRIVER_SUPPORTED_INCOMPAT ( EXT2_FEATURE_INCOMPAT_FILETYPE \
| EXT4_FEATURE_INCOMPAT_EXTENTS \
| EXT4_FEATURE_INCOMPAT_FLEX_BG \
| EXT2_FEATURE_INCOMPAT_META_BG \
| EXT4_FEATURE_INCOMPAT_64BIT)
/* List of rationales for the ignored "incompatible" features:
* needs_recovery: Not really back-incompatible - was added as such to forbid
* ext2 drivers from mounting an ext3 volume with a dirty
* journal because they will ignore the journal, but the next
* ext3 driver to mount the volume will find the journal and
* replay it, potentially corrupting the metadata written by
* the ext2 drivers. Safe to ignore for this RO driver.
* mmp: Not really back-incompatible - was added as such to
* avoid multiple read-write mounts. Safe to ignore for this
* RO driver.
*/
#define EXT2_DRIVER_IGNORED_INCOMPAT ( EXT3_FEATURE_INCOMPAT_RECOVER \
| EXT4_FEATURE_INCOMPAT_MMP)
#define EXT3_JOURNAL_MAGIC_NUMBER 0xc03b3998U
#define EXT3_JOURNAL_DESCRIPTOR_BLOCK 1
#define EXT3_JOURNAL_COMMIT_BLOCK 2
#define EXT3_JOURNAL_SUPERBLOCK_V1 3
#define EXT3_JOURNAL_SUPERBLOCK_V2 4
#define EXT3_JOURNAL_REVOKE_BLOCK 5
#define EXT3_JOURNAL_FLAG_ESCAPE 1
#define EXT3_JOURNAL_FLAG_SAME_UUID 2
#define EXT3_JOURNAL_FLAG_DELETED 4
#define EXT3_JOURNAL_FLAG_LAST_TAG 8
#define EXT4_EXTENTS_FLAG 0x80000
/* The ext2 superblock. */
struct grub_ext2_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_uint16_t uuid[8];
char volume_name[16];
char last_mounted_on[64];
grub_uint32_t compression_info;
grub_uint8_t prealloc_blocks;
grub_uint8_t prealloc_dir_blocks;
grub_uint16_t reserved_gdt_blocks;
grub_uint8_t journal_uuid[16];
grub_uint32_t journal_inum;
grub_uint32_t journal_dev;
grub_uint32_t last_orphan;
grub_uint32_t hash_seed[4];
grub_uint8_t def_hash_version;
grub_uint8_t jnl_backup_type;
grub_uint16_t group_desc_size;
grub_uint32_t default_mount_opts;
grub_uint32_t first_meta_bg;
grub_uint32_t mkfs_time;
grub_uint32_t jnl_blocks[17];
};
/* The ext2 blockgroup. */
struct grub_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 used_dirs;
grub_uint16_t pad;
grub_uint32_t reserved[3];
grub_uint32_t block_id_hi;
grub_uint32_t inode_id_hi;
grub_uint32_t inode_table_id_hi;
grub_uint16_t free_blocks_hi;
grub_uint16_t free_inodes_hi;
grub_uint16_t used_dirs_hi;
grub_uint16_t pad2;
grub_uint32_t reserved2[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 triple_indir_block;
} blocks;
char symlink[60];
};
grub_uint32_t version;
grub_uint32_t acl;
grub_uint32_t size_high;
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;
#define MAX_NAMELEN 255
grub_uint8_t namelen;
grub_uint8_t filetype;
};
struct grub_ext3_journal_header
{
grub_uint32_t magic;
grub_uint32_t block_type;
grub_uint32_t sequence;
};
struct grub_ext3_journal_revoke_header
{
struct grub_ext3_journal_header header;
grub_uint32_t count;
grub_uint32_t data[0];
};
struct grub_ext3_journal_block_tag
{
grub_uint32_t block;
grub_uint32_t flags;
};
struct grub_ext3_journal_sblock
{
struct grub_ext3_journal_header header;
grub_uint32_t block_size;
grub_uint32_t maxlen;
grub_uint32_t first;
grub_uint32_t sequence;
grub_uint32_t start;
};
#define EXT4_EXT_MAGIC 0xf30a
struct grub_ext4_extent_header
{
grub_uint16_t magic;
grub_uint16_t entries;
grub_uint16_t max;
grub_uint16_t depth;
grub_uint32_t generation;
};
struct grub_ext4_extent
{
grub_uint32_t block;
grub_uint16_t len;
grub_uint16_t start_hi;
grub_uint32_t start;
};
struct grub_ext4_extent_idx
{
grub_uint32_t block;
grub_uint32_t leaf;
grub_uint16_t leaf_hi;
grub_uint16_t unused;
};
struct grub_fshelp_node
{
struct grub_ext2_data *data;
struct grub_ext2_inode inode;
int ino;
int inode_read;
};
/* Information about a "mounted" ext2 filesystem. */
struct grub_ext2_data
{
struct grub_ext2_sblock sblock;
int log_group_desc_size;
grub_disk_t disk;
struct grub_ext2_inode *inode;
struct grub_fshelp_node diropen;
};
static grub_dl_t my_mod;
/* Check is a = b^x for some x. */
static inline int
is_power_of (grub_uint64_t a, grub_uint32_t b)
{
grub_uint64_t c;
/* Prevent overflow assuming b < 8. */
if (a >= (1LL << 60))
return 0;
for (c = 1; c <= a; c *= b);
return (c == a);
}
static inline int
group_has_super_block (struct grub_ext2_data *data, grub_uint64_t group)
{
if (!(data->sblock.feature_ro_compat
& grub_cpu_to_le32_compile_time(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)))
return 1;
/* Algorithm looked up in Linux source. */
if (group <= 1)
return 1;
/* Even number is never a power of odd number. */
if (!(group & 1))
return 0;
return (is_power_of(group, 7) || is_power_of(group, 5) ||
is_power_of(group, 3));
}
/* 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, grub_uint64_t group,
struct grub_ext2_block_group *blkgrp)
{
grub_uint64_t full_offset = (group << data->log_group_desc_size);
grub_uint64_t block, offset;
block = (full_offset >> LOG2_BLOCK_SIZE (data));
offset = (full_offset & ((1 << LOG2_BLOCK_SIZE (data)) - 1));
if ((data->sblock.feature_incompat
& grub_cpu_to_le32_compile_time (EXT2_FEATURE_INCOMPAT_META_BG))
&& block >= grub_le_to_cpu32(data->sblock.first_meta_bg))
{
grub_uint64_t first_block_group;
/* Find the first block group for which a descriptor
is stored in given block. */
first_block_group = (block << (LOG2_BLOCK_SIZE (data)
- data->log_group_desc_size));
block = (first_block_group
* grub_le_to_cpu32(data->sblock.blocks_per_group));
if (group_has_super_block (data, first_block_group))
block++;
}
else
/* Superblock. */
block++;
return grub_disk_read (data->disk,
((grub_le_to_cpu32 (data->sblock.first_data_block)
+ block)
<< LOG2_EXT2_BLOCK_SIZE (data)), offset,
sizeof (struct grub_ext2_block_group), blkgrp);
}
static struct grub_ext4_extent_header *
grub_ext4_find_leaf (struct grub_ext2_data *data,
struct grub_ext4_extent_header *ext_block,
grub_uint32_t fileblock)
{
struct grub_ext4_extent_idx *index;
void *buf = NULL;
while (1)
{
int i;
grub_disk_addr_t block;
index = (struct grub_ext4_extent_idx *) (ext_block + 1);
if (ext_block->magic != grub_cpu_to_le16_compile_time (EXT4_EXT_MAGIC))
goto fail;
if (ext_block->depth == 0)
return ext_block;
for (i = 0; i < grub_le_to_cpu16 (ext_block->entries); i++)
{
if (fileblock < grub_le_to_cpu32(index[i].block))
break;
}
if (--i < 0)
goto fail;
block = grub_le_to_cpu16 (index[i].leaf_hi);
block = (block << 32) | grub_le_to_cpu32 (index[i].leaf);
if (!buf)
buf = grub_malloc (EXT2_BLOCK_SIZE(data));
if (!buf)
goto fail;
if (grub_disk_read (data->disk,
block << LOG2_EXT2_BLOCK_SIZE (data),
0, EXT2_BLOCK_SIZE(data), buf))
goto fail;
ext_block = buf;
}
fail:
grub_free (buf);
return 0;
}
static grub_disk_addr_t
grub_ext2_read_block (grub_fshelp_node_t node, grub_disk_addr_t fileblock)
{
struct grub_ext2_data *data = node->data;
struct grub_ext2_inode *inode = &node->inode;
unsigned int blksz = EXT2_BLOCK_SIZE (data);
grub_disk_addr_t blksz_quarter = blksz / 4;
int log2_blksz = LOG2_EXT2_BLOCK_SIZE (data);
int log_perblock = log2_blksz + 9 - 2;
grub_uint32_t indir;
int shift;
if (inode->flags & grub_cpu_to_le32_compile_time (EXT4_EXTENTS_FLAG))
{
struct grub_ext4_extent_header *leaf;
struct grub_ext4_extent *ext;
int i;
grub_disk_addr_t ret;
leaf = grub_ext4_find_leaf (data, (struct grub_ext4_extent_header *) inode->blocks.dir_blocks, fileblock);
if (! leaf)
{
grub_error (GRUB_ERR_BAD_FS, "invalid extent");
return -1;
}
ext = (struct grub_ext4_extent *) (leaf + 1);
for (i = 0; i < grub_le_to_cpu16 (leaf->entries); i++)
{
if (fileblock < grub_le_to_cpu32 (ext[i].block))
break;
}
if (--i >= 0)
{
fileblock -= grub_le_to_cpu32 (ext[i].block);
if (fileblock >= grub_le_to_cpu16 (ext[i].len))
ret = 0;
else
{
grub_disk_addr_t start;
start = grub_le_to_cpu16 (ext[i].start_hi);
start = (start << 32) + grub_le_to_cpu32 (ext[i].start);
ret = fileblock + start;
}
}
else
{
grub_error (GRUB_ERR_BAD_FS, "something wrong with extent");
ret = -1;
}
if (leaf != (struct grub_ext4_extent_header *) inode->blocks.dir_blocks)
grub_free (leaf);
return ret;
}
/* Direct blocks. */
if (fileblock < INDIRECT_BLOCKS)
return grub_le_to_cpu32 (inode->blocks.dir_blocks[fileblock]);
fileblock -= INDIRECT_BLOCKS;
/* Indirect. */
if (fileblock < blksz_quarter)
{
indir = inode->blocks.indir_block;
shift = 0;
goto indirect;
}
fileblock -= blksz_quarter;
/* Double indirect. */
if (fileblock < blksz_quarter * blksz_quarter)
{
indir = inode->blocks.double_indir_block;
shift = 1;
goto indirect;
}
fileblock -= blksz_quarter * blksz_quarter;
/* Triple indirect. */
if (fileblock < blksz_quarter * blksz_quarter * (blksz_quarter + 1))
{
indir = inode->blocks.triple_indir_block;
shift = 2;
goto indirect;
}
return grub_error (GRUB_ERR_BAD_FS,
"ext2fs doesn't support quadruple indirect blocks");
indirect:
do {
/* If the indirect block is zero, all child blocks are absent
(i.e. filled with zeros.) */
if (indir == 0)
return 0;
if (grub_disk_read (data->disk,
((grub_disk_addr_t) grub_le_to_cpu32 (indir))
<< log2_blksz,
((fileblock >> (log_perblock * shift))
& ((1 << log_perblock) - 1))
* sizeof (indir),
sizeof (indir), &indir))
return grub_errno;
} while (shift--);
return grub_le_to_cpu32 (indir);
}
/* 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 (grub_fshelp_node_t node,
grub_disk_read_hook_t read_hook, void *read_hook_data,
grub_off_t pos, grub_size_t len, char *buf)
{
return grub_fshelp_read_file (node->data->disk, node,
read_hook, read_hook_data,
pos, len, buf, grub_ext2_read_block,
grub_cpu_to_le32 (node->inode.size)
| (((grub_off_t) grub_cpu_to_le32 (node->inode.size_high)) << 32),
LOG2_EXT2_BLOCK_SIZE (node->data), 0);
}
/* 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 grub_ext2_block_group blkgrp;
struct grub_ext2_sblock *sblock = &data->sblock;
int inodes_per_block;
unsigned int blkno;
unsigned int blkoff;
grub_disk_addr_t base;
/* 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) / EXT2_INODE_SIZE (data);
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;
base = grub_le_to_cpu32 (blkgrp.inode_table_id);
if (data->log_group_desc_size >= 6)
base |= (((grub_disk_addr_t) grub_le_to_cpu32 (blkgrp.inode_table_id_hi))
<< 32);
/* Read the inode. */
if (grub_disk_read (data->disk,
((base + blkno) << LOG2_EXT2_BLOCK_SIZE (data)),
EXT2_INODE_SIZE (data) * blkoff,
sizeof (struct grub_ext2_inode), 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_ext2_sblock),
&data->sblock);
if (grub_errno)
goto fail;
/* Make sure this is an ext2 filesystem. */
if (data->sblock.magic != grub_cpu_to_le16_compile_time (EXT2_MAGIC)
|| grub_le_to_cpu32 (data->sblock.log2_block_size) >= 16
|| data->sblock.inodes_per_group == 0
/* 20 already means 1GiB blocks. We don't want to deal with blocks overflowing int32. */
|| grub_le_to_cpu32 (data->sblock.log2_block_size) > 20
|| EXT2_INODE_SIZE (data) == 0
|| EXT2_BLOCK_SIZE (data) / EXT2_INODE_SIZE (data) == 0)
{
grub_error (GRUB_ERR_BAD_FS, "not an ext2 filesystem");
goto fail;
}
/* Check the FS doesn't have feature bits enabled that we don't support. */
if (data->sblock.revision_level != grub_cpu_to_le32_compile_time (EXT2_GOOD_OLD_REVISION)
&& (data->sblock.feature_incompat
& grub_cpu_to_le32_compile_time (~(EXT2_DRIVER_SUPPORTED_INCOMPAT
| EXT2_DRIVER_IGNORED_INCOMPAT))))
{
grub_error (GRUB_ERR_BAD_FS, "filesystem has unsupported incompatible features");
goto fail;
}
if (data->sblock.revision_level != grub_cpu_to_le32_compile_time (EXT2_GOOD_OLD_REVISION)
&& (data->sblock.feature_incompat
& grub_cpu_to_le32_compile_time (EXT4_FEATURE_INCOMPAT_64BIT))
&& data->sblock.group_desc_size != 0
&& ((data->sblock.group_desc_size & (data->sblock.group_desc_size - 1))
== 0)
&& (data->sblock.group_desc_size & grub_cpu_to_le16_compile_time (0x1fe0)))
{
grub_uint16_t b = grub_le_to_cpu16 (data->sblock.group_desc_size);
for (data->log_group_desc_size = 0; b != (1 << data->log_group_desc_size);
data->log_group_desc_size++);
}
else
data->log_group_desc_size = 5;
data->disk = disk;
data->diropen.data = data;
data->diropen.ino = 2;
data->diropen.inode_read = 1;
data->inode = &data->diropen.inode;
grub_ext2_read_inode (data, 2, data->inode);
if (grub_errno)
goto fail;
return data;
fail:
if (grub_errno == GRUB_ERR_OUT_OF_RANGE)
grub_error (GRUB_ERR_BAD_FS, "not an ext2 filesystem");
grub_free (data);
return 0;
}
static char *
grub_ext2_read_symlink (grub_fshelp_node_t node)
{
char *symlink;
struct grub_fshelp_node *diro = node;
if (! diro->inode_read)
{
grub_ext2_read_inode (diro->data, diro->ino, &diro->inode);
if (grub_errno)
return 0;
}
symlink = grub_malloc (grub_le_to_cpu32 (diro->inode.size) + 1);
if (! symlink)
return 0;
/* 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 (diro->inode.size) <= sizeof (diro->inode.symlink))
grub_memcpy (symlink,
diro->inode.symlink,
grub_le_to_cpu32 (diro->inode.size));
else
{
grub_ext2_read_file (diro, 0, 0, 0,
grub_le_to_cpu32 (diro->inode.size),
symlink);
if (grub_errno)
{
grub_free (symlink);
return 0;
}
}
symlink[grub_le_to_cpu32 (diro->inode.size)] = '\0';
return symlink;
}
static int
grub_ext2_iterate_dir (grub_fshelp_node_t dir,
grub_fshelp_iterate_dir_hook_t hook, void *hook_data)
{
unsigned int fpos = 0;
struct grub_fshelp_node *diro = (struct grub_fshelp_node *) dir;
if (! diro->inode_read)
{
grub_ext2_read_inode (diro->data, diro->ino, &diro->inode);
if (grub_errno)
return 0;
}
/* Search the file. */
while (fpos < grub_le_to_cpu32 (diro->inode.size))
{
struct ext2_dirent dirent;
grub_ext2_read_file (diro, 0, 0, fpos, sizeof (struct ext2_dirent),
(char *) &dirent);
if (grub_errno)
return 0;
if (dirent.direntlen == 0)
return 0;
if (dirent.inode != 0 && dirent.namelen != 0)
{
char filename[MAX_NAMELEN + 1];
struct grub_fshelp_node *fdiro;
enum grub_fshelp_filetype type = GRUB_FSHELP_UNKNOWN;
grub_ext2_read_file (diro, 0, 0, fpos + sizeof (struct ext2_dirent),
dirent.namelen, filename);
if (grub_errno)
return 0;
fdiro = grub_malloc (sizeof (struct grub_fshelp_node));
if (! fdiro)
return 0;
fdiro->data = diro->data;
fdiro->ino = grub_le_to_cpu32 (dirent.inode);
filename[dirent.namelen] = '\0';
if (dirent.filetype != FILETYPE_UNKNOWN)
{
fdiro->inode_read = 0;
if (dirent.filetype == FILETYPE_DIRECTORY)
type = GRUB_FSHELP_DIR;
else if (dirent.filetype == FILETYPE_SYMLINK)
type = GRUB_FSHELP_SYMLINK;
else if (dirent.filetype == FILETYPE_REG)
type = GRUB_FSHELP_REG;
}
else
{
/* The filetype can not be read from the dirent, read
the inode to get more information. */
grub_ext2_read_inode (diro->data,
grub_le_to_cpu32 (dirent.inode),
&fdiro->inode);
if (grub_errno)
{
grub_free (fdiro);
return 0;
}
fdiro->inode_read = 1;
if ((grub_le_to_cpu16 (fdiro->inode.mode)
& FILETYPE_INO_MASK) == FILETYPE_INO_DIRECTORY)
type = GRUB_FSHELP_DIR;
else if ((grub_le_to_cpu16 (fdiro->inode.mode)
& FILETYPE_INO_MASK) == FILETYPE_INO_SYMLINK)
type = GRUB_FSHELP_SYMLINK;
else if ((grub_le_to_cpu16 (fdiro->inode.mode)
& FILETYPE_INO_MASK) == FILETYPE_INO_REG)
type = GRUB_FSHELP_REG;
}
if (hook (filename, type, fdiro, hook_data))
return 1;
}
fpos += grub_le_to_cpu16 (dirent.direntlen);
}
return 0;
}
/* 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;
struct grub_fshelp_node *fdiro = 0;
grub_err_t err;
grub_dl_ref (my_mod);
data = grub_ext2_mount (file->device->disk);
if (! data)
{
err = grub_errno;
goto fail;
}
err = grub_fshelp_find_file (name, &data->diropen, &fdiro,
grub_ext2_iterate_dir,
grub_ext2_read_symlink, GRUB_FSHELP_REG);
if (err)
goto fail;
if (! fdiro->inode_read)
{
err = grub_ext2_read_inode (data, fdiro->ino, &fdiro->inode);
if (err)
goto fail;
}
grub_memcpy (data->inode, &fdiro->inode, sizeof (struct grub_ext2_inode));
grub_free (fdiro);
file->size = grub_le_to_cpu32 (data->inode->size);
file->size |= ((grub_off_t) grub_le_to_cpu32 (data->inode->size_high)) << 32;
file->data = data;
file->offset = 0;
return 0;
fail:
if (fdiro != &data->diropen)
grub_free (fdiro);
grub_free (data);
grub_dl_unref (my_mod);
return err;
}
static grub_err_t
grub_ext2_close (grub_file_t file)
{
grub_free (file->data);
grub_dl_unref (my_mod);
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_size_t len)
{
struct grub_ext2_data *data = (struct grub_ext2_data *) file->data;
return grub_ext2_read_file (&data->diropen,
file->read_hook, file->read_hook_data,
file->offset, len, buf);
}
/* Context for grub_ext2_dir. */
struct grub_ext2_dir_ctx
{
grub_fs_dir_hook_t hook;
void *hook_data;
struct grub_ext2_data *data;
};
/* Helper for grub_ext2_dir. */
static int
grub_ext2_dir_iter (const char *filename, enum grub_fshelp_filetype filetype,
grub_fshelp_node_t node, void *data)
{
struct grub_ext2_dir_ctx *ctx = data;
struct grub_dirhook_info info;
grub_memset (&info, 0, sizeof (info));
if (! node->inode_read)
{
grub_ext2_read_inode (ctx->data, node->ino, &node->inode);
if (!grub_errno)
node->inode_read = 1;
grub_errno = GRUB_ERR_NONE;
}
if (node->inode_read)
{
info.mtimeset = 1;
info.mtime = grub_le_to_cpu32 (node->inode.mtime);
}
info.dir = ((filetype & GRUB_FSHELP_TYPE_MASK) == GRUB_FSHELP_DIR);
grub_free (node);
return ctx->hook (filename, &info, ctx->hook_data);
}
static grub_err_t
grub_ext2_dir (grub_device_t device, const char *path, grub_fs_dir_hook_t hook,
void *hook_data)
{
struct grub_ext2_dir_ctx ctx = {
.hook = hook,
.hook_data = hook_data
};
struct grub_fshelp_node *fdiro = 0;
grub_dl_ref (my_mod);
ctx.data = grub_ext2_mount (device->disk);
if (! ctx.data)
goto fail;
grub_fshelp_find_file (path, &ctx.data->diropen, &fdiro,
grub_ext2_iterate_dir, grub_ext2_read_symlink,
GRUB_FSHELP_DIR);
if (grub_errno)
goto fail;
grub_ext2_iterate_dir (fdiro, grub_ext2_dir_iter, &ctx);
fail:
if (fdiro != &ctx.data->diropen)
grub_free (fdiro);
grub_free (ctx.data);
grub_dl_unref (my_mod);
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;
grub_dl_ref (my_mod);
data = grub_ext2_mount (disk);
if (data)
*label = grub_strndup (data->sblock.volume_name,
sizeof (data->sblock.volume_name));
else
*label = NULL;
grub_dl_unref (my_mod);
grub_free (data);
return grub_errno;
}
static grub_err_t
grub_ext2_uuid (grub_device_t device, char **uuid)
{
struct grub_ext2_data *data;
grub_disk_t disk = device->disk;
grub_dl_ref (my_mod);
data = grub_ext2_mount (disk);
if (data)
{
*uuid = grub_xasprintf ("%04x%04x-%04x-%04x-%04x-%04x%04x%04x",
grub_be_to_cpu16 (data->sblock.uuid[0]),
grub_be_to_cpu16 (data->sblock.uuid[1]),
grub_be_to_cpu16 (data->sblock.uuid[2]),
grub_be_to_cpu16 (data->sblock.uuid[3]),
grub_be_to_cpu16 (data->sblock.uuid[4]),
grub_be_to_cpu16 (data->sblock.uuid[5]),
grub_be_to_cpu16 (data->sblock.uuid[6]),
grub_be_to_cpu16 (data->sblock.uuid[7]));
}
else
*uuid = NULL;
grub_dl_unref (my_mod);
grub_free (data);
return grub_errno;
}
/* Get mtime. */
static grub_err_t
grub_ext2_mtime (grub_device_t device, grub_int32_t *tm)
{
struct grub_ext2_data *data;
grub_disk_t disk = device->disk;
grub_dl_ref (my_mod);
data = grub_ext2_mount (disk);
if (!data)
*tm = 0;
else
*tm = grub_le_to_cpu32 (data->sblock.utime);
grub_dl_unref (my_mod);
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,
.uuid = grub_ext2_uuid,
.mtime = grub_ext2_mtime,
#ifdef GRUB_UTIL
.reserved_first_sector = 1,
.blocklist_install = 1,
#endif
.next = 0
};
GRUB_MOD_INIT(ext2)
{
grub_fs_register (&grub_ext2_fs);
my_mod = mod;
}
GRUB_MOD_FINI(ext2)
{
grub_fs_unregister (&grub_ext2_fs);
}
Reference in a new issue View git blame Copy permalink