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.\"     @(#)kvm_getvfsbyname.3	8.3 (Berkeley) 5/4/95
.\" $FreeBSD: head/lib/libc/gen/getvfsbyname.3 185029 2008-11-17 20:49:29Z pjd $
.\"
.Dd April 5, 2007
.Dt GETVFSBYNAME 3
.Os
.Sh NAME
.Nm getvfsbyname
.Nd get information about a file system
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/param.h
.In sys/mount.h
.Ft int
.Fn getvfsbyname "const char *name" "struct xvfsconf *vfc"
.Sh DESCRIPTION
The
.Fn getvfsbyname
function provides access to information about a
file system module that is configured in the kernel.
If successful,
the requested file system
.Fa xvfsconf
is returned in the location pointed to by
.Fa vfc .
The fields in a
.Dq Li struct xvfsconf
are defined as follows:
.Pp
.Bl -tag -compact -width vfc_refcount
.It vfc_name
the name of the file system
.It vfc_typenum
the file system type number assigned by the kernel
.It vfc_refcount
the number of active mount points using the file system
.It vfc_flags
flag bits, as described below
.El
.Pp
The flags are defined as follows:
.Pp
.Bl -tag -width VFCF_DELEGADMIN -compact
.It Dv VFCF_STATIC
statically compiled into kernel
.It Dv VFCF_NETWORK
may get data over the network
.It Dv VFCF_READONLY
writes are not implemented
.It Dv VFCF_SYNTHETIC
data does not represent real files
.It Dv VFCF_LOOPBACK
aliases some other mounted FS
.It Dv VFCF_UNICODE
stores file names as Unicode
.It Dv VFCF_JAIL
can be mounted from within a jail if
.Va security.jail.mount_allowed
sysctl is set to
.Dv 1
.It Dv VFCF_DELEGADMIN
supports delegated administration if
.Va vfs.usermount
sysctl is set to
.Dv 1
.El
.Sh RETURN VALUES
.Rv -std getvfsbyname
.Sh ERRORS
The following errors may be reported:
.Bl -tag -width Er
.It Bq Er EFAULT
The
.Fa vfc
argument
points to an invalid address.
.It Bq Er ENOENT
The
.Fa name
argument
specifies a file system that is unknown or not configured in the kernel.
.El
.Sh SEE ALSO
.Xr jail 2 ,
.Xr mount 2 ,
.Xr sysctl 3 ,
.Xr jail 8 ,
.Xr mount 8 ,
.Xr sysctl 8
.Sh HISTORY
A variant of the
.Fn getvfsbyname
function first appeared in
.Fx 2.0 .