0afc94c17a
bottom of the manpages and order them consistently. GNU groff doesn't care about the ordering, and doesn't even mention CAVEATS and SECURITY CONSIDERATIONS as common sections and where to put them. Found by: mdocml lint run Reviewed by: ru
249 lines
6.1 KiB
Groff
249 lines
6.1 KiB
Groff
.\" Copyright (c) 1988, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" the American National Standards Committee X3, on Information
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.\" Processing Systems.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)tmpnam.3 8.2 (Berkeley) 11/17/93
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.\" $FreeBSD$
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.\"
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.Dd March 18, 2007
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.Dt TMPFILE 3
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.Os
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.Sh NAME
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.Nm tempnam ,
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.Nm tmpfile ,
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.Nm tmpnam
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.Nd temporary file routines
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In stdio.h
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.Ft FILE *
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.Fn tmpfile void
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.Ft char *
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.Fn tmpnam "char *str"
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.Ft char *
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.Fn tempnam "const char *tmpdir" "const char *prefix"
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.Sh DESCRIPTION
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The
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.Fn tmpfile
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function
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returns a pointer to a stream associated with a file descriptor returned
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by the routine
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.Xr mkstemp 3 .
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The created file is unlinked before
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.Fn tmpfile
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returns, causing the file to be automatically deleted when the last
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reference to it is closed.
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The file is opened with the access value
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.Ql w+ .
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The file is created in the directory determined by the environment variable
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.Ev TMPDIR
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if set.
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The default location if
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.Ev TMPDIR
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is not set is
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.Pa /tmp .
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.Pp
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The
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.Fn tmpnam
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function
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returns a pointer to a file name, in the
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.Dv P_tmpdir
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directory, which
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did not reference an existing file at some indeterminate point in the
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past.
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.Dv P_tmpdir
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is defined in the include file
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.In stdio.h .
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If the argument
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.Fa str
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is
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.Pf non- Dv NULL ,
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the file name is copied to the buffer it references.
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Otherwise, the file name is copied to a static buffer.
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In either case,
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.Fn tmpnam
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returns a pointer to the file name.
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.Pp
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The buffer referenced by
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.Fa str
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is expected to be at least
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.Dv L_tmpnam
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bytes in length.
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.Dv L_tmpnam
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is defined in the include file
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.In stdio.h .
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.Pp
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The
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.Fn tempnam
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function
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is similar to
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.Fn tmpnam ,
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but provides the ability to specify the directory which will
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contain the temporary file and the file name prefix.
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.Pp
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The environment variable
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.Ev TMPDIR
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(if set), the argument
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.Fa tmpdir
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(if
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.Pf non- Dv NULL ) ,
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the directory
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.Dv P_tmpdir ,
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and the directory
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.Pa /tmp
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are tried, in the listed order, as directories in which to store the
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temporary file.
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.Pp
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The argument
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.Fa prefix ,
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if
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.Pf non- Dv NULL ,
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is used to specify a file name prefix, which will be the
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first part of the created file name.
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The
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.Fn tempnam
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function
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allocates memory in which to store the file name; the returned pointer
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may be used as a subsequent argument to
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.Xr free 3 .
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.Sh RETURN VALUES
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The
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.Fn tmpfile
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function
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returns a pointer to an open file stream on success, and a
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.Dv NULL
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pointer
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on error.
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.Pp
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The
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.Fn tmpnam
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and
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.Fn tempfile
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functions
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return a pointer to a file name on success, and a
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.Dv NULL
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pointer
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on error.
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.Sh ENVIRONMENT
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.Bl -tag -width Ds
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.It Ev TMPDIR
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.Pf [ Fn tempnam
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only]
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If set,
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the directory in which the temporary file is stored.
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.Ev TMPDIR
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is ignored for processes
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for which
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.Xr issetugid 2
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is true.
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.El
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.Sh COMPATIBILITY
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These interfaces are provided from System V and
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.Tn ANSI
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compatibility only.
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.Pp
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Most historic implementations of these functions provide
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only a limited number of possible temporary file names
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(usually 26)
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before file names will start being recycled.
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System V implementations of these functions
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(and of
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.Xr mktemp 3 )
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use the
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.Xr access 2
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system call to determine whether or not the temporary file
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may be created.
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This has obvious ramifications for setuid or setgid programs,
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complicating the portable use of these interfaces in such programs.
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.Pp
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The
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.Fn tmpfile
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interface should not be used in software expected to be used on other systems
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if there is any possibility that the user does not wish the temporary file to
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be publicly readable and writable.
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.Sh ERRORS
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The
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.Fn tmpfile
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function
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may fail and set the global variable
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.Va errno
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for any of the errors specified for the library functions
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.Xr fdopen 3
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or
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.Xr mkstemp 3 .
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.Pp
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The
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.Fn tmpnam
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function
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may fail and set
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.Va errno
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for any of the errors specified for the library function
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.Xr mktemp 3 .
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.Pp
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The
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.Fn tempnam
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function
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may fail and set
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.Va errno
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for any of the errors specified for the library functions
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.Xr malloc 3
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or
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.Xr mktemp 3 .
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.Sh SEE ALSO
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.Xr mkstemp 3 ,
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.Xr mktemp 3
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.Sh STANDARDS
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The
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.Fn tmpfile
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and
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.Fn tmpnam
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functions
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conform to
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.St -isoC .
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.Sh SECURITY CONSIDERATIONS
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The
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.Fn tmpnam
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and
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.Fn tempnam
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functions are susceptible to a race condition
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occurring between the selection of the file name
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and the creation of the file,
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which allows malicious users
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to potentially overwrite arbitrary files in the system,
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depending on the level of privilege of the running program.
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Additionally, there is no means by which
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file permissions may be specified.
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It is strongly suggested that
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.Xr mkstemp 3
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be used in place of these functions.
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(See
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the FSA.)
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