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443701ef0c7ff30872e27419cf4356fb6bdb4059
xen/tools/libfsimage/ext2fs/fsys_ext2fs.c
T
Ian Campbell 443701ef0c Replace FSF street address with canonical URL 
As recommended in http://www.gnu.org/licenses/gpl-howto.en.html.

This is the result of:
$ git grep -El Mass\|Temple\|Franklin | xargs ./fsf.pl

Where fsf.pl is:
    #!/usr/bin/perl -w -pi.bak -0777
    my $repl = 'If not, see <http://www.gnu.org/licenses/>.';
    my $br = qr/(?:\s*\n\s*(?:[\*\#]|\/\/|\.\\" )?\s*|\s+)/;

    my $inwt = qr/[Ii]f${br}not,${br}write${br}(?:to${br})?the${br}Free${br}Software${br}Foundation,(?:${br}Inc\.,)?/;

    my $mass = qr/675${br}Mass${br}Ave,?${br}Cambridge,?${br}MA${br}02139,?${br}USA,?\.?/;
    my $franklin = qr/51${br}Franklin${br}St(?:reet)?(?:,${br}| - )Fifth${br}Floor,?${br}Boston,?${br}MA,?${br}02110-1301,?${br}USA,?\.?/;
    my $temple = qr/59${br}Temple${br}Place(?:,${br}| - )Suite${br}330,?${br}Boston,?${br}MA,?${br}021110?-1307,?${br}USA,?\.?/;

    s|$inwt$br$mass|$repl|m;
    s|$inwt$br$franklin|$repl|m;
    s|$inwt$br$temple|$repl|m;

The only remaining mentions of these addresses are in COPYING files which I
haven't touched.

Some of the changed files are imports from elsewhere, however
filtering them out is tricky, I think it is tolerable to have these
files be modified here and then perhaps reverted on the next sync,
since it's only 1-2 lines and obvious what is going on.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
2015-07-29 11:14:07 +01:00

917 lines
28 KiB
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/*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <fsimage_grub.h>
#define mapblock1 (*fsig_int1(ffi))
#define mapblock2 (*fsig_int2(ffi))
/* 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)
/* Inode flags */
#define EXT4_EXTENTS_FL 0x00080000 /* Inode uses extents */
/* 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)
/* linux/ext4_fs_extents.h */
/*
* This is the extent on-disk structure.
* It's used at the bottom of the tree.
*/
struct ext4_extent {
__u32 ee_block; /* first logical block extent covers */
__u16 ee_len; /* number of blocks covered by extent */
__u16 ee_start_hi; /* high 16 bits of physical block */
__u32 ee_start; /* low 32 bits of physical block */
};
/*
* This is index on-disk structure.
* It's used at all the levels except the bottom.
*/
struct ext4_extent_idx {
__u32 ei_block; /* index covers logical blocks from 'block' */
__u32 ei_leaf; /* pointer to the physical block of the next *
* level. leaf or next index could be there */
__u16 ei_leaf_hi; /* high 16 bits of physical block */
__u16 ei_unused;
};
/*
* Each block (leaves and indexes), even inode-stored has header.
*/
struct ext4_extent_header {
__u16 eh_magic; /* probably will support different formats */
__u16 eh_entries; /* number of valid entries */
__u16 eh_max; /* capacity of store in entries */
__u16 eh_depth; /* has tree real underlying blocks? */
__u32 eh_generation; /* generation of the tree */
};
#define EXT4_EXT_MAGIC 0xf30a
/* ext2/super.c */
#define log2(n) grub_log2(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 *) \
((char *)SUPERBLOCK + sizeof(struct ext2_super_block)))
#define INODE \
((struct ext2_inode *)((caddr_t)GROUP_DESC + EXT2_BLOCK_SIZE(SUPERBLOCK)))
#define DATABLOCK1 \
((char *)((caddr_t)INODE + sizeof(struct ext2_inode)))
#define DATABLOCK2 \
((char *)((caddr_t)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)
/* check filesystem types and read superblock into memory buffer */
static int
ext2fs_mount (fsi_file_t *ffi, const char *options)
{
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 (ffi, 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 (fsi_file_t *ffi, int fsblock, char *buffer)
{
#ifdef E2DEBUG
printf ("fsblock %d buffer %d\n", fsblock, buffer);
#endif /* E2DEBUG */
return devread (ffi, fsblock * (EXT2_BLOCK_SIZE (SUPERBLOCK) / DEV_BSIZE), 0,
EXT2_BLOCK_SIZE (SUPERBLOCK), (char *) buffer);
}
/* Walk through extents index tree to find the good leaf */
static struct ext4_extent_header *
ext4_recurse_extent_index(fsi_file_t *ffi, struct ext4_extent_header *extent_block, int logical_block)
{
int i;
struct ext4_extent_idx *index = (struct ext4_extent_idx *) (extent_block + 1);
if (extent_block->eh_magic != EXT4_EXT_MAGIC)
return NULL;
if (extent_block->eh_depth == 0)
return extent_block;
for (i = 0; i < extent_block->eh_entries; i++)
{
if (logical_block < index[i].ei_block)
break;
}
if (i == 0 || !ext2_rdfsb(ffi, index[i-1].ei_leaf, DATABLOCK1))
return NULL;
return (ext4_recurse_extent_index(ffi, (struct ext4_extent_header *) DATABLOCK1, logical_block));
}
/* 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 (fsi_file_t *ffi, 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 (!(INODE->i_flags & EXT4_EXTENTS_FL))
{
/* 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 (ffi, 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 (ffi, 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 (ffi, 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 (ffi, INODE->i_block[EXT2_TIND_BLOCK], DATABLOCK1))
{
errnum = ERR_FSYS_CORRUPT;
return -1;
}
mapblock1 = 3;
if (!ext2_rdfsb (ffi, ((__u32 *) DATABLOCK1)
[logical_block >> (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK)
* 2)],
DATABLOCK2))
{
errnum = ERR_FSYS_CORRUPT;
return -1;
}
if (!ext2_rdfsb (ffi, ((__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)];
}
/* inode is in extents format */
else
{
int i;
struct ext4_extent_header *extent_hdr =
ext4_recurse_extent_index(ffi, (struct ext4_extent_header *) INODE->i_block, logical_block);
struct ext4_extent *extent = (struct ext4_extent *) (extent_hdr + 1);
if ( extent_hdr == NULL || extent_hdr->eh_magic != EXT4_EXT_MAGIC)
{
errnum = ERR_FSYS_CORRUPT;
return -1;
}
for (i = 0; i<extent_hdr->eh_entries; i++)
{
if (extent[i].ee_block <= logical_block && logical_block < extent[i].ee_block + extent[i].ee_len && !(extent[i].ee_len>>15))
return (logical_block - extent[i].ee_block + extent[i].ee_start);
}
/* We should not arrive here */
errnum = ERR_FSYS_CORRUPT;
return -1;
}
}
/* preconditions: all preconds of ext2fs_block_map */
static int
ext2fs_read (fsi_file_t *ffi, 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 (ffi, 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 (ffi, 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 (fsi_file_t *ffi)
{
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
*/
static int
ext2fs_dir (fsi_file_t *ffi, 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) */
int inodes_per_block; /* number of inodes in each block */
int inode_offset; /* inode offset in block */
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 (ffi,
(WHICH_SUPER + group_desc + SUPERBLOCK->s_first_data_block),
(char *)GROUP_DESC))
{
return 0;
}
gdp = GROUP_DESC;
inodes_per_block = EXT2_BLOCK_SIZE (SUPERBLOCK) / EXT2_INODE_SIZE(SUPERBLOCK);
inode_offset = ((current_ino - 1) % (SUPERBLOCK->s_inodes_per_group));
ino_blk = gdp[desc].bg_inode_table + (inode_offset / inodes_per_block);
#ifdef E2DEBUG
printf ("inode table fsblock=%d\n", ino_blk);
#endif /* E2DEBUG */
if (!ext2_rdfsb (ffi, ino_blk, (char *)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 ((uint8_t)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 (ffi))
{
/* Read the necessary blocks, and reset the file pointer. */
len = ext2fs_read (ffi, 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 ((uint8_t)*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 ((uint8_t)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 (ffi, blk);
#ifdef E2DEBUG
printf ("fs block=%d\n", map);
#endif /* E2DEBUG */
mapblock2 = -1;
if ((map < 0) || !ext2_rdfsb (ffi, 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 */
}
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 = ext2fs_mount,
.fpo_dir = ext2fs_dir,
.fpo_read = ext2fs_read
};
*name = "ext2fs";
return (fsig_init(fp, &ops));
}
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