NetBSD/lib/libc/sys/mount.2

370 lines
11 KiB
Groff
Raw Normal View History

.\" $NetBSD: mount.2,v 1.23 2000/03/06 09:11:14 enami Exp $
.\"
.\" Copyright (c) 1980, 1989, 1993
.\" The Regents of the University of California. All rights reserved.
1993-03-21 12:45:37 +03:00
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" This product includes software developed by the University of
.\" California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
1998-02-02 08:20:24 +03:00
.\" @(#)mount.2 8.3 (Berkeley) 5/24/95
1993-03-21 12:45:37 +03:00
.\"
1999-11-07 04:26:02 +03:00
.Dd November 7, 1999
1993-03-21 12:45:37 +03:00
.Dt MOUNT 2
.Os
1993-03-21 12:45:37 +03:00
.Sh NAME
.Nm mount ,
.Nm unmount
.Nd mount or dismount a file system
.Sh LIBRARY
.Lb libc
1993-03-21 12:45:37 +03:00
.Sh SYNOPSIS
.Fd #include <sys/param.h>
1993-03-21 12:45:37 +03:00
.Fd #include <sys/mount.h>
.Ft int
1996-02-08 21:33:58 +03:00
.Fn mount "const char *type" "const char *dir" "int flags" "void *data"
1993-03-21 12:45:37 +03:00
.Ft int
.Fn unmount "const char *dir" "int flags"
.Sh DESCRIPTION
The
.Fn mount
function grafts
a file system object onto the system file tree
1993-03-21 12:45:37 +03:00
at the point
.Ar dir .
The argument
.Ar data
describes the file system object to be mounted.
1993-03-21 12:45:37 +03:00
The argument
.Ar type
tells the kernel how to interpret
.Ar data
(See
.Ar type
below).
The contents of the file system
1993-03-21 12:45:37 +03:00
become available through the new mount point
.Ar dir .
Any files in
.Ar dir
at the time
of a successful mount are swept under the carpet so to speak, and
are unavailable until the file system is unmounted.
1993-03-21 12:45:37 +03:00
.Pp
The following
.Ar flags
may be specified to
suppress default semantics which affect file system access.
.Bl -tag -width MNT_SYNCHRONOUS
.It Dv MNT_RDONLY
1993-03-21 12:45:37 +03:00
The file system should be treated as read-only;
Even the super-user may not write on it.
.It Dv MNT_NOEXEC
1993-03-21 12:45:37 +03:00
Do not allow files to be executed from the file system.
.It Dv MNT_NOSUID
1993-03-21 12:45:37 +03:00
Do not honor setuid or setgid bits on files when executing them.
.It Dv MNT_NODEV
1993-03-21 12:45:37 +03:00
Do not interpret special files on the file system.
.It Dv MNT_UNION
Union with underlying filesystem instead of obscuring it.
.It Dv MNT_SYNCHRONOUS
1993-03-21 12:45:37 +03:00
All I/O to the file system should be done synchronously.
.It Dv MNT_ASYNC
All I/O to the file system should be done asynchronously.
1996-10-24 02:54:26 +04:00
.It Dv MNT_NOCOREDUMP
Do not allow programs to dump core files on the file system.
.It Dv MNT_NOATIME
Never update access time in the file system.
.It Dv MNT_SYMPERM
Recognize the permission of symbolic link when reading or traversing.
.It Dv MNT_NODEVMTIME
Never update modification time of device files.
.It Dv MNT_SOFTDEP
Use soft dependencies.
1993-03-21 12:45:37 +03:00
.El
.Pp
The flag
.Dv MNT_UPDATE
1993-03-21 12:45:37 +03:00
indicates that the mount command is being applied
to an already mounted file system.
This allows the mount flags to be changed without requiring
that the file system be unmounted and remounted.
Some file systems may not allow all flags to be changed.
For example,
most file systems will not allow a change from read-write to read-only.
.Pp
The
.Fa type
argument defines the type of the file system.
The types of file systems known to the system are defined in
.Aq Pa sys/mount.h .
1998-02-02 08:20:24 +03:00
.\" XXX from lite-2:
.\" The types of filesystems known to the system can be obtained with
.\" .Xr sysctl 8
.\" by using the command:
.\" .Bd -literal -offset indent
.\" sysctl vfs
.\" .Ed
.\" .Pp
.Fa data
1993-03-21 12:45:37 +03:00
is a pointer to a structure that contains the type
specific arguments to mount.
The currently supported types of file systems and
their type specific data are:
.Pp
.Dv MOUNT_FFS
1993-03-21 12:45:37 +03:00
.Bd -literal -offset indent -compact
struct ufs_args {
char *fspec; /* block special file to mount */
struct export_args export; /* network export information */
1993-03-21 12:45:37 +03:00
};
.Ed
.Pp
.Dv MOUNT_NFS
.Bd -literal -offset indent -compact
struct nfs_args {
int version; /* args structure version */
struct sockaddr *addr; /* file server address */
int addrlen; /* length of address */
int sotype; /* Socket type */
int proto; /* and Protocol */
u_char *fh; /* File handle to be mounted */
int fhsize; /* Size, in bytes, of fh */
int flags; /* flags */
int wsize; /* write size in bytes */
int rsize; /* read size in bytes */
int readdirsize; /* readdir size in bytes */
int timeo; /* initial timeout in .1 secs */
int retrans; /* times to retry send */
int maxgrouplist; /* Max. size of group list */
int readahead; /* # of blocks to readahead */
int leaseterm; /* Term (sec) of lease */
int deadthresh; /* Retrans threshold */
char *hostname; /* server's name */
1993-03-21 12:45:37 +03:00
};
.Ed
.Pp
.Dv MOUNT_MFS
.Bd -literal -offset indent -compact
struct mfs_args {
char *fspec; /* name to export for statfs */
struct export_args export; /* if we can export an MFS */
caddr_t base; /* base of file system in mem */
u_long size; /* size of file system */
1993-03-21 12:45:37 +03:00
};
.Ed
1998-02-02 08:20:24 +03:00
.\" XXX from lite-2:
.\" The format for these argument structures is described in the
.\" manual page for each filesystem.
.\" By convention filesystem manual pages are named
.\" by prefixing ``mount_'' to the name of the filesystem as returned by
.\" .Xr sysctl 8 .
.\" Thus the
.\" .Nm NFS
.\" filesystem is described by the
.\" .Xr mount_nfs 8
.\" manual page.
1993-03-21 12:45:37 +03:00
.Pp
The
.Fn unmount
function call disassociates the file system from the specified
1993-03-21 12:45:37 +03:00
mount point
.Fa dir .
.Pp
The
.Fa flags
argument may specify
.Dv MNT_FORCE
to specify that the file system should be forcibly unmounted even if files are
1993-03-21 12:45:37 +03:00
still active.
Active special devices continue to work,
but any further accesses to any other active files result in errors
even if the file system is later remounted.
.Sh RETURN VALUES
.Fn mount
returns the value 0 if the mount was successful, otherwise -1 is returned
and the variable
.Va errno
is set to indicate the error.
.Pp
1999-11-07 04:26:02 +03:00
.Fn unmount
returns the value 0 if the unmount succeeded; otherwise -1 is returned
1993-03-21 12:45:37 +03:00
and the variable
.Va errno
is set to indicate the error.
.Sh ERRORS
1998-06-08 13:45:50 +04:00
.Fn mount
1993-03-21 12:45:37 +03:00
will fail when one of the following occurs:
.Bl -tag -width Er
1993-03-21 12:45:37 +03:00
.It Bq Er EPERM
The caller is not the super-user.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded
.Dv {NAME_MAX}
characters, or an entire path name exceeded
.Dv {PATH_MAX}
characters.
1993-03-21 12:45:37 +03:00
.It Bq Er ELOOP
Too many symbolic links were encountered in translating a pathname.
.It Bq Er ENOENT
A component of
.Fa dir
does not exist.
.It Bq Er ENOTDIR
A component of
.Ar name
is not a directory,
or a path prefix of
.Ar special
is not a directory.
.It Bq Er EBUSY
Another process currently holds a reference to
.Fa dir .
.It Bq Er EFAULT
.Fa dir
1993-03-21 12:45:37 +03:00
points outside the process's allocated address space.
.El
.Pp
The following errors can occur for a
.Em ufs
file system mount:
.Bl -tag -width Er
1993-03-21 12:45:37 +03:00
.It Bq Er ENODEV
A component of ufs_args
.Ar fspec
does not exist.
.It Bq Er ENOTBLK
.Ar Fspec
is not a block device.
.It Bq Er ENXIO
The major device number of
.Ar fspec
is out of range (this indicates no device driver exists
for the associated hardware).
.It Bq Er EBUSY
.Ar Fspec
is already mounted.
.It Bq Er EMFILE
No space remains in the mount table.
.It Bq Er EINVAL
The super block for the file system had a bad magic
number or an out of range block size.
.It Bq Er ENOMEM
Not enough memory was available to read the cylinder
group information for the file system.
.It Bq Er EIO
An I/O error occurred while reading the super block or
cylinder group information.
.It Bq Er EFAULT
.Ar Fspec
points outside the process's allocated address space.
.El
.Pp
The following errors can occur for a
.Em nfs
file system mount:
.Bl -tag -width Er
1993-03-21 12:45:37 +03:00
.It Bq Er ETIMEDOUT
.Em Nfs
timed out trying to contact the server.
.It Bq Er EFAULT
Some part of the information described by nfs_args
points outside the process's allocated address space.
.El
.Pp
The following errors can occur for a
.Em mfs
file system mount:
.Bl -tag -width Er
1993-03-21 12:45:37 +03:00
.It Bq Er EMFILE
No space remains in the mount table.
.It Bq Er EINVAL
The super block for the file system had a bad magic
number or an out of range block size.
.It Bq Er ENOMEM
Not enough memory was available to read the cylinder
group information for the file system.
.It Bq Er EIO
A paging error occurred while reading the super block or
1993-03-21 12:45:37 +03:00
cylinder group information.
.It Bq Er EFAULT
.Em Name
points outside the process's allocated address space.
.El
.Pp
1999-11-07 04:26:02 +03:00
.Fn unmount
1993-03-21 12:45:37 +03:00
may fail with one of the following errors:
.Bl -tag -width Er
1993-03-21 12:45:37 +03:00
.It Bq Er EPERM
The caller is not the super-user.
.It Bq Er ENOTDIR
A component of the path is not a directory.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded
.Dv {NAME_MAX}
characters, or an entire path name exceeded
.Dv {PATH_MAX}
characters.
1993-03-21 12:45:37 +03:00
.It Bq Er ELOOP
Too many symbolic links were encountered in translating the pathname.
.It Bq Er EINVAL
The requested directory is not in the mount table.
.It Bq Er EBUSY
A process is holding a reference to a file located
on the file system.
.It Bq Er EIO
An I/O error occurred while writing cached file system information.
.It Bq Er EFAULT
.Fa dir
1993-03-21 12:45:37 +03:00
points outside the process's allocated address space.
.El
.Pp
A
.Em ufs
or
.Em mfs
mount can also fail if the maximum number of file systems are currently
1993-03-21 12:45:37 +03:00
mounted.
.Sh SEE ALSO
.Xr getfsstat 2 ,
.Xr getmntinfo 3 ,
1999-09-27 01:18:53 +04:00
.Xr symlink 7 ,
1993-03-21 12:45:37 +03:00
.Xr mount 8 ,
.Xr sysctl 8 ,
.Xr umount 8
1993-03-21 12:45:37 +03:00
.Sh BUGS
Some of the error codes need translation to more obvious messages.
.Sh HISTORY
1999-11-07 04:26:02 +03:00
The
1998-06-08 13:45:50 +04:00
.Fn mount
1993-03-21 12:45:37 +03:00
and
.Fn umount
1999-11-07 04:26:02 +03:00
(now
.Fn unmount )
function calls appeared in
.At v6 .