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alistair23-linux/include/uapi/linux/auto_fs.h
Ian Kent 60d6d04ca3 autofs: add ignore mount option 
Add an autofs file system mount option that can be used to provide a
generic indicator to applications that the mount entry should be ignored
when displaying mount information.

In other OSes that provide autofs and that provide a mount list to user
space based on the kernel mount list a no-op mount option ("ignore" is
the one use on the most common OS) is allowed so that autofs file system
users can optionally use it.

The idea is that it be used by user space programs to exclude autofs
mounts from consideration when reading the mounts list.

Prior to the change to link /etc/mtab to /proc/self/mounts all I needed
to do to achieve this was to use mount(2) and not update the mtab but
now that no longer works.

I know the symlinking happened a long time ago and I considered doing
this then but, at the time I couldn't remember the commonly used option
name and thought persuading the various utility maintainers would be too
hard.

But now I have a RHEL request to do this for compatibility for a widely
used product so I want to go ahead with it and try and enlist the help
of some utility package maintainers.

Clearly, without the option nothing can be done so it's at least a
start.

Link: http://lkml.kernel.org/r/154725123970.11260.6113771566924907275.stgit@pluto-themaw-net
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-07 18:32:01 -08:00

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/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
/*
* Copyright 1997 Transmeta Corporation - All Rights Reserved
* Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
* Copyright 2005-2006,2013,2017-2018 Ian Kent <raven@themaw.net>
*
* This file is part of the Linux kernel and is made available under
* the terms of the GNU General Public License, version 2, or at your
* option, any later version, incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
#ifndef _UAPI_LINUX_AUTO_FS_H
#define _UAPI_LINUX_AUTO_FS_H
#include <linux/types.h>
#include <linux/limits.h>
#ifndef __KERNEL__
#include <sys/ioctl.h>
#endif /* __KERNEL__ */
#define AUTOFS_PROTO_VERSION 5
#define AUTOFS_MIN_PROTO_VERSION 3
#define AUTOFS_MAX_PROTO_VERSION 5
#define AUTOFS_PROTO_SUBVERSION 5
/*
* The wait_queue_token (autofs_wqt_t) is part of a structure which is passed
* back to the kernel via ioctl from userspace. On architectures where 32- and
* 64-bit userspace binaries can be executed it's important that the size of
* autofs_wqt_t stays constant between 32- and 64-bit Linux kernels so that we
* do not break the binary ABI interface by changing the structure size.
*/
#if defined(__ia64__) || defined(__alpha__) /* pure 64bit architectures */
typedef unsigned long autofs_wqt_t;
#else
typedef unsigned int autofs_wqt_t;
#endif
/* Packet types */
#define autofs_ptype_missing 0 /* Missing entry (mount request) */
#define autofs_ptype_expire 1 /* Expire entry (umount request) */
struct autofs_packet_hdr {
int proto_version; /* Protocol version */
int type; /* Type of packet */
};
struct autofs_packet_missing {
struct autofs_packet_hdr hdr;
autofs_wqt_t wait_queue_token;
int len;
char name[NAME_MAX+1];
};
/* v3 expire (via ioctl) */
struct autofs_packet_expire {
struct autofs_packet_hdr hdr;
int len;
char name[NAME_MAX+1];
};
#define AUTOFS_IOCTL 0x93
enum {
AUTOFS_IOC_READY_CMD = 0x60,
AUTOFS_IOC_FAIL_CMD,
AUTOFS_IOC_CATATONIC_CMD,
AUTOFS_IOC_PROTOVER_CMD,
AUTOFS_IOC_SETTIMEOUT_CMD,
AUTOFS_IOC_EXPIRE_CMD,
};
#define AUTOFS_IOC_READY _IO(AUTOFS_IOCTL, AUTOFS_IOC_READY_CMD)
#define AUTOFS_IOC_FAIL _IO(AUTOFS_IOCTL, AUTOFS_IOC_FAIL_CMD)
#define AUTOFS_IOC_CATATONIC _IO(AUTOFS_IOCTL, AUTOFS_IOC_CATATONIC_CMD)
#define AUTOFS_IOC_PROTOVER _IOR(AUTOFS_IOCTL, \
AUTOFS_IOC_PROTOVER_CMD, int)
#define AUTOFS_IOC_SETTIMEOUT32 _IOWR(AUTOFS_IOCTL, \
AUTOFS_IOC_SETTIMEOUT_CMD, \
compat_ulong_t)
#define AUTOFS_IOC_SETTIMEOUT _IOWR(AUTOFS_IOCTL, \
AUTOFS_IOC_SETTIMEOUT_CMD, \
unsigned long)
#define AUTOFS_IOC_EXPIRE _IOR(AUTOFS_IOCTL, \
AUTOFS_IOC_EXPIRE_CMD, \
struct autofs_packet_expire)
/* autofs version 4 and later definitions */
/* Mask for expire behaviour */
#define AUTOFS_EXP_NORMAL 0x00
#define AUTOFS_EXP_IMMEDIATE 0x01
#define AUTOFS_EXP_LEAVES 0x02
#define AUTOFS_EXP_FORCED 0x04
#define AUTOFS_TYPE_ANY 0U
#define AUTOFS_TYPE_INDIRECT 1U
#define AUTOFS_TYPE_DIRECT 2U
#define AUTOFS_TYPE_OFFSET 4U
static inline void set_autofs_type_indirect(unsigned int *type)
{
*type = AUTOFS_TYPE_INDIRECT;
}
static inline unsigned int autofs_type_indirect(unsigned int type)
{
return (type == AUTOFS_TYPE_INDIRECT);
}
static inline void set_autofs_type_direct(unsigned int *type)
{
*type = AUTOFS_TYPE_DIRECT;
}
static inline unsigned int autofs_type_direct(unsigned int type)
{
return (type == AUTOFS_TYPE_DIRECT);
}
static inline void set_autofs_type_offset(unsigned int *type)
{
*type = AUTOFS_TYPE_OFFSET;
}
static inline unsigned int autofs_type_offset(unsigned int type)
{
return (type == AUTOFS_TYPE_OFFSET);
}
static inline unsigned int autofs_type_trigger(unsigned int type)
{
return (type == AUTOFS_TYPE_DIRECT || type == AUTOFS_TYPE_OFFSET);
}
/*
* This isn't really a type as we use it to say "no type set" to
* indicate we want to search for "any" mount in the
* autofs_dev_ioctl_ismountpoint() device ioctl function.
*/
static inline void set_autofs_type_any(unsigned int *type)
{
*type = AUTOFS_TYPE_ANY;
}
static inline unsigned int autofs_type_any(unsigned int type)
{
return (type == AUTOFS_TYPE_ANY);
}
/* Daemon notification packet types */
enum autofs_notify {
NFY_NONE,
NFY_MOUNT,
NFY_EXPIRE
};
/* Kernel protocol version 4 packet types */
/* Expire entry (umount request) */
#define autofs_ptype_expire_multi 2
/* Kernel protocol version 5 packet types */
/* Indirect mount missing and expire requests. */
#define autofs_ptype_missing_indirect 3
#define autofs_ptype_expire_indirect 4
/* Direct mount missing and expire requests */
#define autofs_ptype_missing_direct 5
#define autofs_ptype_expire_direct 6
/* v4 multi expire (via pipe) */
struct autofs_packet_expire_multi {
struct autofs_packet_hdr hdr;
autofs_wqt_t wait_queue_token;
int len;
char name[NAME_MAX+1];
};
union autofs_packet_union {
struct autofs_packet_hdr hdr;
struct autofs_packet_missing missing;
struct autofs_packet_expire expire;
struct autofs_packet_expire_multi expire_multi;
};
/* autofs v5 common packet struct */
struct autofs_v5_packet {
struct autofs_packet_hdr hdr;
autofs_wqt_t wait_queue_token;
__u32 dev;
__u64 ino;
__u32 uid;
__u32 gid;
__u32 pid;
__u32 tgid;
__u32 len;
char name[NAME_MAX+1];
};
typedef struct autofs_v5_packet autofs_packet_missing_indirect_t;
typedef struct autofs_v5_packet autofs_packet_expire_indirect_t;
typedef struct autofs_v5_packet autofs_packet_missing_direct_t;
typedef struct autofs_v5_packet autofs_packet_expire_direct_t;
union autofs_v5_packet_union {
struct autofs_packet_hdr hdr;
struct autofs_v5_packet v5_packet;
autofs_packet_missing_indirect_t missing_indirect;
autofs_packet_expire_indirect_t expire_indirect;
autofs_packet_missing_direct_t missing_direct;
autofs_packet_expire_direct_t expire_direct;
};
enum {
AUTOFS_IOC_EXPIRE_MULTI_CMD = 0x66, /* AUTOFS_IOC_EXPIRE_CMD + 1 */
AUTOFS_IOC_PROTOSUBVER_CMD,
AUTOFS_IOC_ASKUMOUNT_CMD = 0x70, /* AUTOFS_DEV_IOCTL_VERSION_CMD - 1 */
};
#define AUTOFS_IOC_EXPIRE_MULTI _IOW(AUTOFS_IOCTL, \
AUTOFS_IOC_EXPIRE_MULTI_CMD, int)
#define AUTOFS_IOC_PROTOSUBVER _IOR(AUTOFS_IOCTL, \
AUTOFS_IOC_PROTOSUBVER_CMD, int)
#define AUTOFS_IOC_ASKUMOUNT _IOR(AUTOFS_IOCTL, \
AUTOFS_IOC_ASKUMOUNT_CMD, int)
#endif /* _UAPI_LINUX_AUTO_FS_H */
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