lis_umount2.9

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.TH UMOUNT 9 "2004/01/12 23:33:07" "LiS-2_16_18-8" "Linux STREAMS DDI/DKI"
.SH NAME
\fBumount\fR, \fBlis_umount\fR - unmount a filesystem
.SH SYNOPSIS
.PP
.B #include <sys/stream.h>
.br
.B #include <sys/dki.h>
.HP 8
.BI "int " retval " = lis_umount2(char *" pathname ", int " flags );
.SH DESCRIPTION
.PP
.BR umount2 ()
is an
.B LiS
.[
LiS
.]
wrapper function to the system call
.BR umount (2)
that can be called from the kernel.
.PP
The purpose of this function being called from the kernel is to permit
.IR STREAMS (4)
kernel modules to mount their own filesystems.
.PP
Normally, a filesystem would be mounted by a
.IR STREAMS (4)
module or driver when the
.B Linux
kernel module loads (i.e. within the
.BR init_module ()
function).
Normally,
.BR umount2 ()
would be called within the kernl module
.BR cleanup_module ()
function to unmount the filesystems that were mounted during module
initialization.
.PP
.I pathname
is the path to the directory to which the file system is attached.
.PP
.I flags
can be one of the following:
.TP 12
.B MTP_FORCE
force unmount the filesystem.
.PP
For additional information, see
.BR umount (2).
.SH "RETURN VALUE"
.PP
Upon success,
.BR umount2 ()
returns zero (0).
Upon failure,
.BR umount2 ()
returns a negative error number.
.SH ERRORS
.PP
When
.BR umount2 ()
fails, it returns a negative error number that can contain any of the errors
listed under
.BR umount (2).
.SH CAVEATS
.PP
.BR umount2 ()
is implemented by changing the data segment to the kernel data segment and
calling
.BR umount (2).
This means that the
.BR uid " and " euid
of the caller is not changed.
This makes this function rather useless if the process invoking it is not the
kernel module loading daemon, or other process running with real root
permission.
.SH "SEE ALSO"
.PP
.BR umount (2),
.BR lis_mount (9),
.BR lis_mknod (9),
.BR lis_unlink (9).
.SH VERSIONS
.PP
This manpage was written for
.B LiS\c
.
.[
LiS
.]
.PP
.BR umount ()
appeared in SVR 2.
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