156 lines
3.7 KiB
C
156 lines
3.7 KiB
C
#ifndef _LINUX_LOOP_H
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#define _LINUX_LOOP_H
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#include <linux/kdev_t.h>
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/*
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* include/linux/loop.h
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*
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* Written by Theodore Ts'o, 3/29/93.
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*
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* Copyright 1993 by Theodore Ts'o. Redistribution of this file is
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* permitted under the GNU General Public License.
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*/
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#define LO_NAME_SIZE 64
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#define LO_KEY_SIZE 32
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#ifdef __KERNEL__
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/* Possible states of device */
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enum {
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Lo_unbound,
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Lo_bound,
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Lo_rundown,
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};
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struct loop_device {
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int lo_number;
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int lo_refcnt;
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kdev_t lo_device;
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int lo_offset;
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int lo_encrypt_type;
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int lo_encrypt_key_size;
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int lo_flags;
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int (*transfer)(struct loop_device *, int cmd,
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char *raw_buf, char *loop_buf, int size,
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int real_block);
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char lo_name[LO_NAME_SIZE];
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char lo_encrypt_key[LO_KEY_SIZE];
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__u32 lo_init[2];
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uid_t lo_key_owner; /* Who set the key */
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int (*ioctl)(struct loop_device *, int cmd,
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unsigned long arg);
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struct file * lo_backing_file;
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void *key_data;
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char key_reserved[48]; /* for use by the filter modules */
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int old_gfp_mask;
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spinlock_t lo_lock;
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struct buffer_head *lo_bh;
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struct buffer_head *lo_bhtail;
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int lo_state;
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struct semaphore lo_sem;
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struct semaphore lo_ctl_mutex;
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struct semaphore lo_bh_mutex;
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atomic_t lo_pending;
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};
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typedef int (* transfer_proc_t)(struct loop_device *, int cmd,
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char *raw_buf, char *loop_buf, int size,
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int real_block);
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static inline int lo_do_transfer(struct loop_device *lo, int cmd, char *rbuf,
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char *lbuf, int size, int rblock)
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{
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if (!lo->transfer)
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return 0;
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return lo->transfer(lo, cmd, rbuf, lbuf, size, rblock);
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}
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#endif /* __KERNEL__ */
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/*
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* Loop flags
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*/
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#define LO_FLAGS_DO_BMAP 1
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#define LO_FLAGS_READ_ONLY 2
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#define LO_FLAGS_BH_REMAP 4
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/*
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* Note that this structure gets the wrong offsets when directly used
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* from a glibc program, because glibc has a 32bit dev_t.
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* Prevent people from shooting in their own foot.
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*/
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#if __GLIBC__ >= 2 && !defined(dev_t)
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#error "Wrong dev_t in loop.h"
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#endif
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/*
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* This uses kdev_t because glibc currently has no appropiate
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* conversion version for the loop ioctls.
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* The situation is very unpleasant
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*/
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struct loop_info {
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int lo_number; /* ioctl r/o */
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dev_t lo_device; /* ioctl r/o */
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unsigned long lo_inode; /* ioctl r/o */
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dev_t lo_rdevice; /* ioctl r/o */
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int lo_offset;
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int lo_encrypt_type;
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int lo_encrypt_key_size; /* ioctl w/o */
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int lo_flags; /* ioctl r/o */
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char lo_name[LO_NAME_SIZE];
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unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
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unsigned long lo_init[2];
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char reserved[4];
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};
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/*
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* Loop filter types
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*/
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#define LO_CRYPT_NONE 0
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#define LO_CRYPT_XOR 1
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#define LO_CRYPT_DES 2
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#define LO_CRYPT_FISH2 3 /* Brand new Twofish encryption */
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#define LO_CRYPT_BLOW 4
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#define LO_CRYPT_CAST128 5
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#define LO_CRYPT_IDEA 6
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#define LO_CRYPT_DUMMY 9
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#define LO_CRYPT_SKIPJACK 10
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#define MAX_LO_CRYPT 20
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#ifdef __KERNEL__
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/* Support for loadable transfer modules */
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struct loop_func_table {
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int number; /* filter type */
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int (*transfer)(struct loop_device *lo, int cmd, char *raw_buf,
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char *loop_buf, int size, int real_block);
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int (*init)(struct loop_device *, struct loop_info *);
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/* release is called from loop_unregister_transfer or clr_fd */
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int (*release)(struct loop_device *);
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int (*ioctl)(struct loop_device *, int cmd, unsigned long arg);
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/* lock and unlock manage the module use counts */
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void (*lock)(struct loop_device *);
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void (*unlock)(struct loop_device *);
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};
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int loop_register_transfer(struct loop_func_table *funcs);
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int loop_unregister_transfer(int number);
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#endif
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/*
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* IOCTL commands --- we will commandeer 0x4C ('L')
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*/
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#define LOOP_SET_FD 0x4C00
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#define LOOP_CLR_FD 0x4C01
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#define LOOP_SET_STATUS 0x4C02
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#define LOOP_GET_STATUS 0x4C03
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#endif
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