.\"	$NetBSD: getfh.2,v 1.21 2006/10/30 18:53:42 mjf Exp $
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.\"	@(#)getfh.2	8.1 (Berkeley) 6/9/93
.\"
.Dd October 30, 2006
.Dt GETFH 2
.Os
.Sh NAME
.Nm getfh
.Nd get file handle
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/types.h
.In sys/mount.h
.Ft int
.Fn getfh "const char *path" "void *fhp" "size_t *fh_size"
.Sh DESCRIPTION
.Fn getfh
returns a file handle for the specified file or directory
in the file handle pointed to by
.Fa fhp .
The variable pointed to by
.Fa fh_size
has to be initialized to the memory allocated for the variable sized file
handle.
On return the value will be replaced by the actual size
needed (which will vary depending on the file system the path is on).
This system call is restricted to the superuser.
To query the necessary size for the filehandle, a
.Dv NULL
pointer may
be passed as
.Fa fhp ,
and the value pointed to by
.Fa fh_size
should be initialized to zero.
.Sh RETURN VALUES
Upon successful completion, a value of 0 is returned.
Otherwise, \-1 is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
.Fn getfh
fails if one or more of the following are true:
.Bl -tag -width Er
.It Bq Er ENOTDIR
A component of the path prefix of
.Fa path
is not a directory.
.It Bq Er ENAMETOOLONG
The length of a component of
.Fa path
exceeds
.Brq Dv NAME_MAX
characters, or the length of
.Fa path
exceeds
.Brq Dv PATH_MAX
characters.
.It Bq Er ENOENT
The file referred to by
.Fa path
does not exist.
.It Bq Er EACCES
Search permission is denied for a component of the path prefix of
.Fa path .
.It Bq Er ELOOP
Too many symbolic links were encountered in translating
.Fa path .
.It Bq Er EFAULT
.Fa fhp
points to an invalid address.
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.It Bq Er E2BIG
The memory allocated for the file handle is too small.
The size needed has been written to the variable pointed to by
.Fa fh_size .
.It Bq Er ENOMEM
The kernel failed to allocate temporary memory to create a filehandle of the
requested size.
.El
.Sh SEE ALSO
.Xr fhstat 2 ,
.Xr fhstatvfs 2 ,
.Xr fhstatvfs1 2
.Sh HISTORY
The
.Fn getfh
function
first appeared in
.Bx 4.4 .