187 lines
5.4 KiB
Groff
187 lines
5.4 KiB
Groff
.\" Copyright (c) 1989, 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.
|
|
.\" 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.
|
|
.\"
|
|
.\" From: $OpenBSD: mktemp.1,v 1.8 1998/03/19 06:13:37 millert Exp $
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd November, 20, 1996
|
|
.Dt MKTEMP 1
|
|
.Os
|
|
.Sh NAME
|
|
.Nm mktemp
|
|
.Nd make temporary file name (unique)
|
|
.Sh SYNOPSIS
|
|
.Nm mktemp
|
|
.Op Fl d
|
|
.Op Fl q
|
|
.Op Fl t Ar prefix
|
|
.Op Fl u
|
|
.Op Ar template ...
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
utility takes each of the given file name templates and overwrites a
|
|
portion of it to create a file name. This file name is unique
|
|
and suitable for use by the application. The template may be
|
|
any file name with some number of
|
|
.Ql X Ns s
|
|
appended
|
|
to it, for example
|
|
.Pa /tmp/temp.XXXX .
|
|
The trailing
|
|
.Ql X Ns s
|
|
are replaced with the current process number and/or a
|
|
unique letter combination.
|
|
The number of unique file names
|
|
.Nm
|
|
can return depends on the number of
|
|
.Ql X Ns s
|
|
provided; six
|
|
.Ql X Ns s
|
|
will
|
|
result in
|
|
.Nm
|
|
testing roughly 26 ** 6 combinations.
|
|
.Pp
|
|
If
|
|
.Nm
|
|
can successfully generate a unique file name, the file
|
|
is created with mode 0600 (unless the
|
|
.Fl u
|
|
flag is given) and the filename is printed
|
|
to standard output.
|
|
.Pp
|
|
If the
|
|
.Fl t Ar prefix
|
|
option is given,
|
|
.Nm
|
|
will generate an template string based on the
|
|
.Ar prefix
|
|
and the
|
|
.Ev TMPDIR
|
|
environment variable if set.
|
|
The default location if
|
|
.Ev TMPDIR
|
|
is not set is
|
|
.Pa /tmp .
|
|
Care should
|
|
be taken to ensure that it is appropriate to use an environment variable
|
|
potentially supplied by the user.
|
|
.Pp
|
|
Any number of temporary files may be created in a single invocation,
|
|
including one based on the internal template resulting from the
|
|
.Fl t
|
|
flag.
|
|
.Pp
|
|
.Nm Mktemp
|
|
is provided to allow shell scripts to safely use temporary files.
|
|
Traditionally, many shell scripts take the name of the program with
|
|
the pid as a suffix and use that as a temporary file name. This
|
|
kind of naming scheme is predictable and the race condition it creates
|
|
is easy for an attacker to win. A safer, though still inferior, approach
|
|
is to make a temporary directory using the same naming scheme. While
|
|
this does allow one to guarantee that a temporary file will not be
|
|
subverted, it still allows a simple denial of service attack. For these
|
|
reasons it is suggested that
|
|
.Nm
|
|
be used instead.
|
|
.Sh OPTIONS
|
|
The available options are as follows:
|
|
.Bl -tag -width indent
|
|
.It Fl d
|
|
Make a directory instead of a file.
|
|
.It Fl q
|
|
Fail silently if an error occurs. This is useful if
|
|
a script does not want error output to go to standard error.
|
|
.It Fl t Ar prefix
|
|
Generate a template (using the supplied
|
|
.Ar prefix
|
|
and
|
|
.Ev TMPDIR
|
|
if set) to create a filename template.
|
|
.It Fl u
|
|
Operate in
|
|
.Dq unsafe
|
|
mode. The temp file will be unlinked before
|
|
.Nm
|
|
exits. This is slightly better than
|
|
.Xr mktemp 3
|
|
but still introduces a race condition. Use of this
|
|
option is not encouraged.
|
|
.El
|
|
.Sh DIAGNOSTICS
|
|
The
|
|
.Nm
|
|
utility
|
|
exits 0 on success, and 1 if an error occurs.
|
|
.Sh EXAMPLES
|
|
The following
|
|
.Xr sh 1
|
|
fragment illustrates a simple use of
|
|
.Nm
|
|
where the script should quit if it cannot get a safe
|
|
temporary file.
|
|
.Bd -literal -offset indent
|
|
tempfoo=`basename $0`
|
|
TMPFILE=`mktemp /tmp/${tempfoo}.XXXXXX` || exit 1
|
|
echo "program output" >> $TMPFILE
|
|
.Ed
|
|
.Pp
|
|
To allow the use of $TMPDIR:
|
|
.Bd -literal -offset indent
|
|
tempfoo=`basename $0`
|
|
TMPFILE=`mktemp -t ${tempfoo}` || exit 1
|
|
echo "program output" >> $TMPFILE
|
|
.Ed
|
|
.Pp
|
|
In this case, we want the script to catch the error itself.
|
|
.Bd -literal -offset indent
|
|
tempfoo=`basename $0`
|
|
TMPFILE=`mktemp -q /tmp/${tempfoo}.XXXXXX`
|
|
if [ $? -ne 0 ]; then
|
|
echo "$0: Can't create temp file, exiting..."
|
|
exit 1
|
|
fi
|
|
.Ed
|
|
.Sh SEE ALSO
|
|
.Xr mkdtemp 3 ,
|
|
.Xr mkstemp 3 ,
|
|
.Xr mktemp 3 ,
|
|
.Xr environ 7
|
|
.Sh HISTORY
|
|
A
|
|
.Nm
|
|
utility appeared in
|
|
.Ox 2.1 .
|
|
This implementation has been written independently based on the man page.
|
|
This man page is taken from
|
|
.Ox
|