freebsd-dev/lib/libc/gen/getfsent.3

.\" Copyright (c) 1983, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" 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.
.\" 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.
.\"
.\"     @(#)getfsent.3	8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd April 7, 2003
.Dt GETFSENT 3
.Os
.Sh NAME
.Nm getfsent ,
.Nm getfsspec ,
.Nm getfsfile ,
.Nm setfsent ,
.Nm endfsent
.Nd get file system descriptor file entry
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In fstab.h
.Ft "struct fstab *"
.Fn getfsent void
.Ft "struct fstab *"
.Fn getfsspec "const char *spec"
.Ft "struct fstab *"
.Fn getfsfile "const char *file"
.Ft int
.Fn setfsent void
.Ft void
.Fn endfsent void
.Ft void
.Fn setfstab "const char *file"
.Ft "const char *"
.Fn getfstab void
.Sh DESCRIPTION
The
.Fn getfsent ,
.Fn getfsspec ,
and
.Fn getfsfile
functions
each return a pointer to an object with the following structure
containing the broken-out fields of a line in the file system
description file,
.In fstab.h .
.Bd -literal -offset indent
struct fstab {
	char	*fs_spec;	/* block special device name */
	char	*fs_file;	/* file system path prefix */
	char	*fs_vfstype;	/* File system type, ufs, nfs */
	char	*fs_mntops;	/* Mount options ala -o */
	char	*fs_type;	/* FSTAB_* from fs_mntops */
	int	fs_freq;	/* dump frequency, in days */
	int	fs_passno;	/* pass number on parallel fsck */
};
.Ed
.Pp
The fields have meanings described in
.Xr fstab 5 .
.Pp
The
.Fn setfsent
function
opens the file (closing any previously opened file) or rewinds it
if it is already open.
.Pp
The
.Fn endfsent
function
closes the file.
.Pp
The
.Fn setfstab
function sets the file to be used by subsequent operations.
The value set by
.Fn setfstab
does not persist across calls to
.Fn endfsent .
.Pp
The
.Fn getfstab
function returns the name of the file that will be used.
.Pp
The
.Fn getfsspec
and
.Fn getfsfile
functions
search the entire file (opening it if necessary) for a matching special
file name or file system file name.
.Pp
For programs wishing to read the entire database,
.Fn getfsent
reads the next entry (opening the file if necessary).
.Pp
All entries in the file with a type field equivalent to
.Dv FSTAB_XX
are ignored.
.Sh RETURN VALUES
The
.Fn getfsent ,
.Fn getfsspec ,
and
.Fn getfsfile
functions
return a
.Dv NULL
pointer on
.Dv EOF
or error.
The
.Fn setfsent
function
returns 0 on failure, 1 on success.
The
.Fn endfsent
function
returns nothing.
.Sh ENVIRONMENT
.Bl -tag -width ".Ev PATH_FSTAB"
.It Ev PATH_FSTAB
If the environment variable
.Ev PATH_FSTAB
is set, all operations are performed against the specified file.
.Ev PATH_FSTAB
will not be honored if the process environment or memory address space is
considered
.Dq tainted .
(See
.Xr issetugid 2
for more information.)
.El
.Sh FILES
.Bl -tag -width /etc/fstab -compact
.It Pa /etc/fstab
.El
.Sh SEE ALSO
.Xr fstab 5
.Sh HISTORY
The
.Fn getfsent
function appeared in
.Bx 4.0 ;
the
.Fn endfsent ,
.Fn getfsfile ,
.Fn getfsspec ,
and
.Fn setfsent
functions appeared in
.Bx 4.3 ;
the
.Fn setfstab
and
.Fn getfstab
functions appeared in
.Fx 5.1 .
.Sh BUGS
These functions use static data storage;
if the data is needed for future use, it should be
copied before any subsequent calls overwrite it.