Commit 497f2fc0 authored by root's avatar root
Browse files

v1.0 extractmd

parent 824620a9
cmd_/home/user/extractmd/extractmd.ko := ld -r -m elf_x86_64 -T ./scripts/module-common.lds --build-id -o /home/user/extractmd/extractmd.ko /home/user/extractmd/extractmd.o /home/user/extractmd/extractmd.mod.o
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/home/user/extractmd/extractmd.ko
/home/user/extractmd/extractmd.o
obj-m += extractmd.o
all:
make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
clean:
make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean
11/11/2016 v1.0
in extractmd.h
ext4_super_group -> extractmd_super_group
ext4_group_desc -> extractmd_group_desc
How to use?
You should make a test code.
"test.c" is an example.
/* Open */
int fd = open("/dev/extractmd", O_RDWR);
/* super_block in user space */
struct extractmd_super_block super_block;
/* ioctl will copy super_block from kernel space */
inctl(fd, &super_block);
/* Now super_block is copied
* ...do sometiing here with super_block...
*/
/* Close */
close(fd);
File added
#include <linux/module.h> // included for all kernel modules
#include <linux/kernel.h> // included for KERN_INFO
#include <linux/init.h> // included for __init and __exit macros
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/mount.h>
#include "linux-4.0.9/fs/ext4/ext4.h"
/* Prototypes */
static int __init init_extractmd(void);
static void __exit cleanup_extractmd(void);
static int extractmd_ioctl(struct inode *, struct file *, struct ext4_super_block *);
static int device_open(struct inode *, struct file *);
static int device_release(struct inode *, struct file *);
static struct ext4_group_desc *get_group_desc(struct super_block *sb, ext4_group_t block_group);
static int copy_super_block(struct ext4_super_block *, struct ext4_super_block *);
#define DEVICE_NAME "extractmd" /* Dev name as it appears in /proc/devices */
/* Global variables are declared as static, so are global within the file.*/
static struct class *my_class;
static dev_t devt;
static struct file_operations fops = {
.open = device_open,
.release = device_release,
.unlocked_ioctl = extractmd_ioctl,
};
static int __init init_extractmd(void)
{
printk(KERN_INFO "extractmd is registered in /proc/devices\n");
printk(KERN_INFO "/dev/extractmd is maked.\n");
printk(KERN_INFO "create class\n");
register_chrdev(199, DEVICE_NAME, &fops);
devt = MKDEV(199,0);
my_class = class_create(THIS_MODULE, DEVICE_NAME);
device_create(my_class, NULL, devt, NULL, DEVICE_NAME);
return 0;
}
static void __exit cleanup_extractmd(void)
{
/* Unregister the device */
unregister_chrdev(199, DEVICE_NAME);
device_destroy(my_class, devt);
class_destroy(my_class);
printk(KERN_INFO "unregister extractmd, destroy dev node and class\n");
printk(KERN_INFO "Cleaning up module.\n");
}
static int extractmd_ioctl(struct inode *inode, struct file *f, struct ext4_super_block *addr)
{
struct file *fp = filp_open("/mnt", O_RDONLY, 0);
struct super_block *sb = fp->f_inode->i_sb; // get super_block of vfs
//struct super_block *sb = fp->f_path.mnt->mnt_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb); // get ext4_sb_info
struct ext4_super_block *sbt = sbi->s_es; // get ext4_super_block
struct ext4_group_desc *gdp = NULL;
ext4_group_t ngroup = sbi->s_groups_count;
//unsigned long i = 0;
int ret = 0;
// unsigned long tmp = 99;
// int ret = copy_to_user(addr, &tmp, sizeof(unsigned long));
// if( addr == NULL)
// {
// printk(KERN_INFO "NULL POINTER\n");
// return 0;
// }
printk(KERN_INFO "Extractmd start!\n");
freeze_super(sb);
// printk(KERN_INFO "Free inode counts : %lu\n", (unsigned long)sbi->s_es->s_free_inodes_count);
// printk(KERN_INFO "Groups with sparse_super2 SBs : %lu,%lu\n", (unsigned long)sbt->s_backup_bgs[0], (unsigned long)sbt->s_backup_bgs[1]);
// printk(KERN_INFO "Number of groups in fs : %lu\n", (unsigned long)ngroup);
// printk(KERN_INFO "=========================================================\n");
/* for (i = 0; i < ngroup; i++) {
gdp = get_group_desc(sb, i);
printk(KERN_INFO "Group %lu\n", i);
printk(KERN_INFO "Block bitmap at %lu\n", (unsigned long)gdp->bg_block_bitmap_lo);
printk(KERN_INFO "Inode bitmap at %lu\n", (unsigned long)gdp->bg_inode_bitmap_lo);
printk(KERN_INFO "Inode table location : %lu\n", (unsigned long)gdp->bg_inode_table_lo);
printk(KERN_INFO "Free inode counts : %lu\n", (unsigned long)gdp->bg_free_inodes_count_lo);
}*/
ret = copy_super_block(addr, sbt);
printk(KERN_INFO "%d left\n", ret);
thaw_super(sb);
return 0;
}
static struct ext4_group_desc *get_group_desc(struct super_block *sb, ext4_group_t block_group)
{
unsigned int group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
unsigned int offset = block_group &(EXT4_DESC_PER_BLOCK(sb) - 1);
struct ext4_sb_info *sbi = EXT4_SB(sb);
return (struct ext4_group_desc *)((__u8 *)sbi->s_group_desc[group_desc]->b_data + offset * EXT4_DESC_SIZE(sb));
}
/* Called when a process tries to open the device file */
static int device_open(struct inode *inode, struct file *file)
{
return 0;
}
/* Called when a process closes the device file */
static int device_release(struct inode *inode, struct file *file)
{
return 0;
}
static int copy_super_block(struct ext4_super_block *dst, struct ext4_super_block *src)
{
int ret = copy_to_user(dst, src, sizeof(struct ext4_super_block));
return ret;
}
module_init(init_extractmd);
module_exit(cleanup_extractmd);
MODULE_LICENSE("GPL");
\ No newline at end of file
#include <linux/types.h>
/*
* Structure of the super block
*/
struct extractmd_super_block {
/*00*/ __le32 s_inodes_count; /* Inodes count */
__le32 s_blocks_count_lo; /* Blocks count */
__le32 s_r_blocks_count_lo; /* Reserved blocks count */
__le32 s_free_blocks_count_lo; /* Free blocks count */
/*10*/ __le32 s_free_inodes_count; /* Free inodes count */
__le32 s_first_data_block; /* First Data Block */
__le32 s_log_block_size; /* Block size */
__le32 s_log_cluster_size; /* Allocation cluster size */
/*20*/ __le32 s_blocks_per_group; /* # Blocks per group */
__le32 s_clusters_per_group; /* # Clusters per group */
__le32 s_inodes_per_group; /* # Inodes per group */
__le32 s_mtime; /* Mount time */
/*30*/ __le32 s_wtime; /* Write time */
__le16 s_mnt_count; /* Mount count */
__le16 s_max_mnt_count; /* Maximal mount count */
__le16 s_magic; /* Magic signature */
__le16 s_state; /* File system state */
__le16 s_errors; /* Behaviour when detecting errors */
__le16 s_minor_rev_level; /* minor revision level */
/*40*/ __le32 s_lastcheck; /* time of last check */
__le32 s_checkinterval; /* max. time between checks */
__le32 s_creator_os; /* OS */
__le32 s_rev_level; /* Revision level */
/*50*/ __le16 s_def_resuid; /* Default uid for reserved blocks */
__le16 s_def_resgid; /* Default gid for reserved blocks */
/*
* These fields are for EXT4_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...
*/
__le32 s_first_ino; /* First non-reserved inode */
__le16 s_inode_size; /* size of inode structure */
__le16 s_block_group_nr; /* block group # of this superblock */
__le32 s_feature_compat; /* compatible feature set */
/*60*/ __le32 s_feature_incompat; /* incompatible feature set */
__le32 s_feature_ro_compat; /* readonly-compatible feature set */
/*68*/ __u8 s_uuid[16]; /* 128-bit uuid for volume */
/*78*/ char s_volume_name[16]; /* volume name */
/*88*/ char s_last_mounted[64]; /* directory where last mounted */
/*C8*/ __le32 s_algorithm_usage_bitmap; /* For compression */
/*
* Performance hints. Directory preallocation should only
* happen if the EXT4_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 */
__le16 s_reserved_gdt_blocks; /* Per group desc for online growth */
/*
* Journaling support valid if EXT4_FEATURE_COMPAT_HAS_JOURNAL set.
*/
/*D0*/ __u8 s_journal_uuid[16]; /* uuid of journal superblock */
/*E0*/ __le32 s_journal_inum; /* inode number of journal file */
__le32 s_journal_dev; /* device number of journal file */
__le32 s_last_orphan; /* start of list of inodes to delete */
__le32 s_hash_seed[4]; /* HTREE hash seed */
__u8 s_def_hash_version; /* Default hash version to use */
__u8 s_jnl_backup_type;
__le16 s_desc_size; /* size of group descriptor */
/*100*/ __le32 s_default_mount_opts;
__le32 s_first_meta_bg; /* First metablock block group */
__le32 s_mkfs_time; /* When the filesystem was created */
__le32 s_jnl_blocks[17]; /* Backup of the journal inode */
/* 64bit support valid if EXT4_FEATURE_COMPAT_64BIT */
/*150*/ __le32 s_blocks_count_hi; /* Blocks count */
__le32 s_r_blocks_count_hi; /* Reserved blocks count */
__le32 s_free_blocks_count_hi; /* Free blocks count */
__le16 s_min_extra_isize; /* All inodes have at least # bytes */
__le16 s_want_extra_isize; /* New inodes should reserve # bytes */
__le32 s_flags; /* Miscellaneous flags */
__le16 s_raid_stride; /* RAID stride */
__le16 s_mmp_update_interval; /* # seconds to wait in MMP checking */
__le64 s_mmp_block; /* Block for multi-mount protection */
__le32 s_raid_stripe_width; /* blocks on all data disks (N*stride)*/
__u8 s_log_groups_per_flex; /* FLEX_BG group size */
__u8 s_checksum_type; /* metadata checksum algorithm used */
__le16 s_reserved_pad;
__le64 s_kbytes_written; /* nr of lifetime kilobytes written */
__le32 s_snapshot_inum; /* Inode number of active snapshot */
__le32 s_snapshot_id; /* sequential ID of active snapshot */
__le64 s_snapshot_r_blocks_count; /* reserved blocks for active
snapshot's future use */
__le32 s_snapshot_list; /* inode number of the head of the
on-disk snapshot list */
#define EXT4_S_ERR_START offsetof(struct ext4_super_block, s_error_count)
__le32 s_error_count; /* number of fs errors */
__le32 s_first_error_time; /* first time an error happened */
__le32 s_first_error_ino; /* inode involved in first error */
__le64 s_first_error_block; /* block involved of first error */
__u8 s_first_error_func[32]; /* function where the error happened */
__le32 s_first_error_line; /* line number where error happened */
__le32 s_last_error_time; /* most recent time of an error */
__le32 s_last_error_ino; /* inode involved in last error */
__le32 s_last_error_line; /* line number where error happened */
__le64 s_last_error_block; /* block involved of last error */
__u8 s_last_error_func[32]; /* function where the error happened */
#define EXT4_S_ERR_END offsetof(struct ext4_super_block, s_mount_opts)
__u8 s_mount_opts[64];
__le32 s_usr_quota_inum; /* inode for tracking user quota */
__le32 s_grp_quota_inum; /* inode for tracking group quota */
__le32 s_overhead_clusters; /* overhead blocks/clusters in fs */
__le32 s_backup_bgs[2]; /* groups with sparse_super2 SBs */
__u8 s_encrypt_algos[4]; /* Encryption algorithms in use */
__le32 s_reserved[105]; /* Padding to the end of the block */
__le32 s_checksum; /* crc32c(superblock) */
};
/*
* Structure of a blocks group descriptor
*/
struct extractmd_group_desc
{
__le32 bg_block_bitmap_lo; /* Blocks bitmap block */
__le32 bg_inode_bitmap_lo; /* Inodes bitmap block */
__le32 bg_inode_table_lo; /* Inodes table block */
__le16 bg_free_blocks_count_lo;/* Free blocks count */
__le16 bg_free_inodes_count_lo;/* Free inodes count */
__le16 bg_used_dirs_count_lo; /* Directories count */
__le16 bg_flags; /* EXT4_BG_flags (INODE_UNINIT, etc) */
__le32 bg_exclude_bitmap_lo; /* Exclude bitmap for snapshots */
__le16 bg_block_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+bbitmap) LE */
__le16 bg_inode_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+ibitmap) LE */
__le16 bg_itable_unused_lo; /* Unused inodes count */
__le16 bg_checksum; /* crc16(sb_uuid+group+desc) */
__le32 bg_block_bitmap_hi; /* Blocks bitmap block MSB */
__le32 bg_inode_bitmap_hi; /* Inodes bitmap block MSB */
__le32 bg_inode_table_hi; /* Inodes table block MSB */
__le16 bg_free_blocks_count_hi;/* Free blocks count MSB */
__le16 bg_free_inodes_count_hi;/* Free inodes count MSB */
__le16 bg_used_dirs_count_hi; /* Directories count MSB */
__le16 bg_itable_unused_hi; /* Unused inodes count MSB */
__le32 bg_exclude_bitmap_hi; /* Exclude bitmap block MSB */
__le16 bg_block_bitmap_csum_hi;/* crc32c(s_uuid+grp_num+bbitmap) BE */
__le16 bg_inode_bitmap_csum_hi;/* crc32c(s_uuid+grp_num+ibitmap) BE */
__u32 bg_reserved;
};
#include <linux/module.h>
#include <linux/vermagic.h>
#include <linux/compiler.h>
MODULE_INFO(vermagic, VERMAGIC_STRING);
__visible struct module __this_module
__attribute__((section(".gnu.linkonce.this_module"))) = {
.name = KBUILD_MODNAME,
.init = init_module,
#ifdef CONFIG_MODULE_UNLOAD
.exit = cleanup_module,
#endif
.arch = MODULE_ARCH_INIT,
};
static const char __module_depends[]
__used
__attribute__((section(".modinfo"))) =
"depends=";
#
# NOTE! Don't add files that are generated in specific
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NOTE! This copyright does *not* cover user programs that use kernel
services by normal system calls - this is merely considered normal use
of the kernel, and does *not* fall under the heading of "derived work".
Also note that the GPL below is copyrighted by the Free Software
Foundation, but the instance of code that it refers to (the Linux
kernel) is copyrighted by me and others who actually wrote it.
Also note that the only valid version of the GPL as far as the kernel
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Linus Torvalds
----------------------------------------