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grub/grub-core/fs/squash4.c

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/* squash4.c - SquashFS */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2010 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/>.
*/
#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>
#include <grub/deflate.h>
GRUB_MOD_LICENSE ("GPLv3+");
/*
object format Pointed by
superblock RAW Fixed offset (0)
data RAW ? Fixed offset (60)
inode table Chunk superblock
dir table Chunk superblock
fragment table Chunk unk1
unk1 RAW, Chunk superblock
unk2 RAW superblock
UID/GID Chunk exttblptr
exttblptr RAW superblock
UID/GID table is the array ot uint32_t
unk1 contains pointer to unk3 followed by some chunk.
unk2 containts one uint64_t
*/
struct grub_squash_super
{
grub_uint32_t magic;
#define SQUASH_MAGIC 0x73717368
grub_uint32_t dummy1;
grub_uint32_t creation_time;
grub_uint32_t dummy2;
grub_uint64_t dummy3;
grub_uint8_t flags;
#define SQUASH_FLAG_UNCOMPRESSED_INODES 1
#define SQUASH_FLAG_UNCOMPRESSED_DATA 2
#define SQUASH_FLAG_UNCOMPRESSED_FRAGMENTS 8
grub_uint8_t dummy4[7];
grub_uint16_t root_ino_offset;
grub_uint32_t root_ino_chunk;
grub_uint16_t dummy5;
grub_uint64_t total_size;
grub_uint64_t exttbloffset;
grub_uint64_t dummy6;
grub_uint64_t inodeoffset;
grub_uint64_t diroffset;
grub_uint64_t unk1offset;
grub_uint64_t unk2offset;
} __attribute__ ((packed));
/* Chunk-based */
struct grub_squash_inode
{
/* Same values as direlem types. */
grub_uint16_t type;
grub_uint16_t dummy[3];
grub_uint32_t mtime;
union
{
struct {
grub_uint32_t dummy;
grub_uint32_t chunk;
grub_uint32_t fragment;
grub_uint32_t offset;
grub_uint32_t size;
} __attribute__ ((packed)) file;
struct {
grub_uint32_t dummy1;
grub_uint32_t chunk;
grub_uint32_t dummy2;
grub_uint16_t size;
grub_uint32_t offset;
grub_uint16_t dummy3;
} __attribute__ ((packed)) dir;
struct {
grub_uint64_t dummy;
grub_uint32_t namelen;
char name[0];
} __attribute__ ((packed)) symlink;
} __attribute__ ((packed));
} __attribute__ ((packed));
/* Chunk-based. */
struct grub_squash_dirent_header
{
/* Actually the value is the number of elements - 1. */
grub_uint32_t nelems;
grub_uint64_t ino_chunk;
} __attribute__ ((packed));
struct grub_squash_dirent
{
grub_uint16_t ino_offset;
grub_uint16_t dummy;
grub_uint16_t type;
#define SQUASH_TYPE_DIR 1
#define SQUASH_TYPE_REGULAR 2
#define SQUASH_TYPE_SYMLINK 3
/* Actually the value is the length of name - 1. */
grub_uint16_t namelen;
char name[0];
} __attribute__ ((packed));
struct grub_squash_frag_desc
{
grub_uint64_t offset;
grub_uint64_t dummy;
} __attribute__ ((packed));
#define SQUASH_CHUNK_SIZE 0x2000
#define SQUASH_CHUNK_FLAGS 0x8000
#define SQUASH_CHUNK_UNCOMPRESSED 0x8000
struct grub_squash_data
{
grub_disk_t disk;
struct grub_squash_super sb;
struct grub_squash_inode ino;
grub_uint64_t fragments;
};
struct grub_fshelp_node
{
struct grub_squash_data *data;
struct grub_squash_inode ino;
grub_uint32_t ino_chunk;
grub_uint16_t ino_offset;
};
static grub_err_t
read_chunk (grub_disk_t disk, void *buf, grub_size_t len,
grub_uint64_t chunk, grub_off_t offset)
{
grub_uint64_t chunk_start;
chunk_start = grub_le_to_cpu64 (chunk);
while (len > 0)
{
grub_uint64_t csize;
grub_uint16_t d;
grub_err_t err;
while (1)
{
err = grub_disk_read (disk, chunk_start >> GRUB_DISK_SECTOR_BITS,
chunk_start & (GRUB_DISK_SECTOR_SIZE - 1),
sizeof (d), &d);
if (err)
return err;
if (offset < SQUASH_CHUNK_SIZE)
break;
offset -= SQUASH_CHUNK_SIZE;
chunk_start += 2 + (grub_le_to_cpu16 (d) & ~SQUASH_CHUNK_FLAGS);
}
csize = SQUASH_CHUNK_SIZE - offset;
if (csize > len)
csize = len;
if (grub_le_to_cpu16 (d) & SQUASH_CHUNK_UNCOMPRESSED)
{
grub_disk_addr_t a = chunk_start + 2 + offset;
err = grub_disk_read (disk, (a >> GRUB_DISK_SECTOR_BITS),
a & (GRUB_DISK_SECTOR_SIZE - 1),
csize, buf);
if (err)
return err;
}
else
{
char *tmp;
grub_size_t bsize = grub_le_to_cpu16 (d) & ~SQUASH_CHUNK_FLAGS;
grub_disk_addr_t a = chunk_start + 2;
tmp = grub_malloc (bsize);
if (!tmp)
return grub_errno;
/* FIXME: buffer uncompressed data. */
err = grub_disk_read (disk, (a >> GRUB_DISK_SECTOR_BITS),
a & (GRUB_DISK_SECTOR_SIZE - 1),
bsize, tmp);
if (err)
{
grub_free (tmp);
return err;
}
if (grub_zlib_decompress (tmp, bsize, offset,
buf, csize) < 0)
{
grub_free (tmp);
return grub_errno;
}
grub_free (tmp);
}
len -= csize;
offset += csize;
buf = (char *) buf + csize;
}
return GRUB_ERR_NONE;
}
static struct grub_squash_data *
squash_mount (grub_disk_t disk)
{
struct grub_squash_super sb;
grub_err_t err;
struct grub_squash_data *data;
grub_uint64_t frag;
err = grub_disk_read (disk, 0, 0, sizeof (sb), &sb);
if (grub_errno == GRUB_ERR_OUT_OF_RANGE)
grub_error (GRUB_ERR_BAD_FS, "not a squash4");
if (err)
return NULL;
if (grub_le_to_cpu32 (sb.magic) != SQUASH_MAGIC)
{
grub_error (GRUB_ERR_BAD_FS, "not squash4");
return NULL;
}
err = grub_disk_read (disk, grub_le_to_cpu32 (sb.unk1offset)
>> GRUB_DISK_SECTOR_BITS,
grub_le_to_cpu32 (sb.unk1offset)
& (GRUB_DISK_SECTOR_SIZE - 1), sizeof (frag), &frag);
if (grub_errno == GRUB_ERR_OUT_OF_RANGE)
grub_error (GRUB_ERR_BAD_FS, "not a squash4");
if (err)
return NULL;
data = grub_malloc (sizeof (*data));
if (!data)
return NULL;
data->sb = sb;
data->disk = disk;
data->fragments = frag;
return data;
}
static char *
grub_squash_read_symlink (grub_fshelp_node_t node)
{
char *ret;
grub_err_t err;
ret = grub_malloc (grub_le_to_cpu32 (node->ino.symlink.namelen) + 1);
err = read_chunk (node->data->disk, ret,
grub_le_to_cpu32 (node->ino.symlink.namelen),
grub_le_to_cpu64 (node->data->sb.inodeoffset)
+ node->ino_chunk,
node->ino_offset + (node->ino.symlink.name
- (char *) &node->ino));
if (err)
{
grub_free (ret);
return NULL;
}
ret[grub_le_to_cpu32 (node->ino.symlink.namelen)] = 0;
return ret;
}
static int
grub_squash_iterate_dir (grub_fshelp_node_t dir,
int NESTED_FUNC_ATTR
(*hook) (const char *filename,
enum grub_fshelp_filetype filetype,
grub_fshelp_node_t node))
{
grub_uint32_t off = grub_le_to_cpu16 (dir->ino.dir.offset);
grub_uint32_t endoff;
unsigned i;
/* FIXME: why - 3 ? */
endoff = grub_le_to_cpu32 (dir->ino.dir.size) + off - 3;
while (off < endoff)
{
struct grub_squash_dirent_header dh;
grub_err_t err;
err = read_chunk (dir->data->disk, &dh, sizeof (dh),
grub_le_to_cpu64 (dir->data->sb.diroffset)
+ grub_le_to_cpu32 (dir->ino.dir.chunk), off);
if (err)
return 0;
off += sizeof (dh);
for (i = 0; i < (unsigned) grub_le_to_cpu16 (dh.nelems) + 1; i++)
{
char *buf;
int r;
struct grub_fshelp_node *node;
enum grub_fshelp_filetype filetype = GRUB_FSHELP_REG;
struct grub_squash_dirent di;
struct grub_squash_inode ino;
err = read_chunk (dir->data->disk, &di, sizeof (di),
grub_le_to_cpu64 (dir->data->sb.diroffset)
+ grub_le_to_cpu32 (dir->ino.dir.chunk), off);
if (err)
return 0;
off += sizeof (di);
err = read_chunk (dir->data->disk, &ino, sizeof (ino),
grub_le_to_cpu64 (dir->data->sb.inodeoffset)
+ grub_le_to_cpu32 (dh.ino_chunk),
grub_cpu_to_le16 (di.ino_offset));
if (err)
return 0;
buf = grub_malloc (grub_le_to_cpu16 (di.namelen) + 2);
if (!buf)
return 0;
err = read_chunk (dir->data->disk, buf,
grub_le_to_cpu16 (di.namelen) + 1,
grub_le_to_cpu64 (dir->data->sb.diroffset)
+ grub_le_to_cpu32 (dir->ino.dir.chunk), off);
if (err)
return 0;
off += grub_le_to_cpu16 (di.namelen) + 1;
buf[grub_le_to_cpu16 (di.namelen) + 1] = 0;
if (grub_le_to_cpu16 (di.type) == SQUASH_TYPE_DIR)
filetype = GRUB_FSHELP_DIR;
if (grub_le_to_cpu16 (di.type) == SQUASH_TYPE_SYMLINK)
filetype = GRUB_FSHELP_SYMLINK;
node = grub_malloc (sizeof (*node));
if (! node)
return 0;
*node = *dir;
node->ino = ino;
node->ino_chunk = grub_le_to_cpu32 (dh.ino_chunk);
node->ino_offset = grub_le_to_cpu16 (di.ino_offset);
r = hook (buf, filetype, node);
grub_free (buf);
if (r)
return r;
}
}
return 0;
}
static grub_err_t
make_root_node (struct grub_squash_data *data, struct grub_fshelp_node *root)
{
grub_memset (root, 0, sizeof (*root));
root->data = data;
return read_chunk (data->disk, &root->ino, sizeof (root->ino),
grub_le_to_cpu64 (data->sb.inodeoffset)
+ grub_le_to_cpu16 (data->sb.root_ino_chunk),
grub_cpu_to_le16 (data->sb.root_ino_offset));
}
static grub_err_t
grub_squash_dir (grub_device_t device, const char *path,
int (*hook) (const char *filename,
const struct grub_dirhook_info *info))
{
auto int NESTED_FUNC_ATTR iterate (const char *filename,
enum grub_fshelp_filetype filetype,
grub_fshelp_node_t node);
int NESTED_FUNC_ATTR iterate (const char *filename,
enum grub_fshelp_filetype filetype,
grub_fshelp_node_t node)
{
struct grub_dirhook_info info;
grub_memset (&info, 0, sizeof (info));
info.dir = ((filetype & GRUB_FSHELP_TYPE_MASK) == GRUB_FSHELP_DIR);
info.mtimeset = 1;
info.mtime = grub_le_to_cpu32 (node->ino.mtime);
return hook (filename, &info);
}
struct grub_squash_data *data = 0;
struct grub_fshelp_node *fdiro = 0;
struct grub_fshelp_node root;
grub_err_t err;
data = squash_mount (device->disk);
if (! data)
return grub_errno;
err = make_root_node (data, &root);
if (err)
return err;
grub_fshelp_find_file (path, &root, &fdiro, grub_squash_iterate_dir,
grub_squash_read_symlink, GRUB_FSHELP_DIR);
if (!grub_errno)
grub_squash_iterate_dir (fdiro, iterate);
grub_free (data);
return grub_errno;
}
static grub_err_t
grub_squash_open (struct grub_file *file, const char *name)
{
struct grub_squash_data *data = 0;
struct grub_fshelp_node *fdiro = 0;
struct grub_fshelp_node root;
grub_err_t err;
data = squash_mount (file->device->disk);
if (! data)
return grub_errno;
err = make_root_node (data, &root);
if (err)
return err;
grub_fshelp_find_file (name, &root, &fdiro, grub_squash_iterate_dir,
grub_squash_read_symlink, GRUB_FSHELP_REG);
if (grub_errno)
{
grub_free (data);
return grub_errno;
}
file->data = data;
data->ino = fdiro->ino;
file->size = grub_le_to_cpu32 (fdiro->ino.file.size);
return GRUB_ERR_NONE;
}
static grub_ssize_t
grub_squash_read_data (struct grub_squash_data *data,
grub_disk_t disk, const struct grub_squash_inode *ino,
grub_off_t off, char *buf, grub_size_t len)
{
grub_err_t err;
grub_uint64_t a, b;
int compressed = 0;
if (grub_le_to_cpu16 (ino->file.fragment) == 0xffff)
{
if (grub_le_to_cpu32 (ino->file.chunk))
a = grub_le_to_cpu32 (ino->file.chunk);
else
a = sizeof (struct grub_squash_super);
compressed = !(data->sb.flags & SQUASH_FLAG_UNCOMPRESSED_DATA);
}
else
{
struct grub_squash_frag_desc frag;
err = read_chunk (disk, &frag, sizeof (frag),
data->fragments, sizeof (frag)
* grub_le_to_cpu16 (ino->file.fragment));
if (err)
return -1;
a = grub_le_to_cpu64 (frag.offset) + grub_le_to_cpu32 (ino->file.chunk);
compressed = !(data->sb.flags & SQUASH_FLAG_UNCOMPRESSED_FRAGMENTS);
}
b = grub_le_to_cpu32 (data->ino.file.offset) + off;
/* FIXME: cache uncompressed chunks. */
if (compressed)
err = grub_zlib_disk_read (disk, a, b, buf, len);
else
err = grub_disk_read (disk, (a + b) >> GRUB_DISK_SECTOR_BITS,
(a + b) & (GRUB_DISK_SECTOR_SIZE - 1), len, buf);
if (err)
return -1;
return len;
}
static grub_ssize_t
grub_squash_read (grub_file_t file, char *buf, grub_size_t len)
{
struct grub_squash_data *data = file->data;
return grub_squash_read_data (data, file->device->disk, &data->ino,
file->offset, buf, len);
}
static grub_err_t
grub_squash_close (grub_file_t file)
{
grub_free (file->data);
return GRUB_ERR_NONE;
}
static grub_err_t
grub_squash_mtime (grub_device_t dev, grub_int32_t *tm)
{
struct grub_squash_data *data = 0;
data = squash_mount (dev->disk);
if (! data)
return grub_errno;
*tm = grub_le_to_cpu32 (data->sb.creation_time);
grub_free (data);
return GRUB_ERR_NONE;
}
static struct grub_fs grub_squash_fs =
{
.name = "squash4",
.dir = grub_squash_dir,
.open = grub_squash_open,
.read = grub_squash_read,
.close = grub_squash_close,
.mtime = grub_squash_mtime,
#ifdef GRUB_UTIL
.reserved_first_sector = 0,
#endif
.next = 0
};
GRUB_MOD_INIT(squash4)
{
grub_fs_register (&grub_squash_fs);
}
GRUB_MOD_FINI(squash4)
{
grub_fs_unregister (&grub_squash_fs);
}
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