mirror of https://github.com/mkerrisk/man-pages
145 lines
4.2 KiB
Groff
145 lines
4.2 KiB
Groff
.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
|
|
.\" and Copyright (C) 2008, Michael Kerrisk <mtk.manpages@gmail.com>
|
|
.\"
|
|
.\" Permission is granted to make and distribute verbatim copies of this
|
|
.\" manual provided the copyright notice and this permission notice are
|
|
.\" preserved on all copies.
|
|
.\"
|
|
.\" Permission is granted to copy and distribute modified versions of this
|
|
.\" manual under the conditions for verbatim copying, provided that the
|
|
.\" entire resulting derived work is distributed under the terms of a
|
|
.\" permission notice identical to this one.
|
|
.\"
|
|
.\" Since the Linux kernel and libraries are constantly changing, this
|
|
.\" manual page may be incorrect or out-of-date. The author(s) assume no
|
|
.\" responsibility for errors or omissions, or for damages resulting from
|
|
.\" the use of the information contained herein. The author(s) may not
|
|
.\" have taken the same level of care in the production of this manual,
|
|
.\" which is licensed free of charge, as they might when working
|
|
.\" professionally.
|
|
.\"
|
|
.\" Formatted or processed versions of this manual, if unaccompanied by
|
|
.\" the source, must acknowledge the copyright and authors of this work.
|
|
.\"
|
|
.\" References consulted:
|
|
.\" Linux libc source code
|
|
.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
|
|
.\" 386BSD man pages
|
|
.\" Modified Sat Jul 24 18:48:48 1993 by Rik Faith (faith@cs.unc.edu)
|
|
.\" Modified 980310, aeb
|
|
.\" Modified 990328, aeb
|
|
.\" 2008-06-19, mtk, Added mkostemp(); various other changes
|
|
.\"
|
|
.TH MKSTEMP 3 2008-06-19 "GNU" "Linux Programmer's Manual"
|
|
.SH NAME
|
|
mkstemp, mkostemp \- create a unique temporary file
|
|
.SH SYNOPSIS
|
|
.nf
|
|
.B #include <stdlib.h>
|
|
.sp
|
|
.BI "int mkstemp(char *" template );
|
|
.sp
|
|
.BI "int mkostemp (char *" template ", int " flags );
|
|
.fi
|
|
.sp
|
|
.in -4n
|
|
Feature Test Macro Requirements for glibc (see
|
|
.BR feature_test_macros (7)):
|
|
.in
|
|
.sp
|
|
.BR mkstemp ():
|
|
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 500
|
|
.br
|
|
.BR mkostemp ():
|
|
_GNU_SOURCE
|
|
.SH DESCRIPTION
|
|
The
|
|
.BR mkstemp ()
|
|
function generates a unique temporary filename from
|
|
.IR template ,
|
|
creates and opens the file,
|
|
and returns an open file descriptor for the file.
|
|
|
|
The last six characters of
|
|
.I template
|
|
must be "XXXXXX" and these are replaced with a string that makes the
|
|
filename unique.
|
|
Since it will be modified,
|
|
.I template
|
|
must not be a string constant, but should be declared as a character array.
|
|
|
|
The file is created with
|
|
permissions 0600, that is, read plus write for owner only.
|
|
(In glibc versions 2.06 and earlier, the file is created with permissions 0666,
|
|
that is, read and write for all users.)
|
|
The returned file descriptor provides both read and write access to the file.
|
|
The file is opened with the
|
|
.BR open (2)
|
|
.B O_EXCL
|
|
flag, guaranteeing that the caller is the process that creates the file.
|
|
|
|
.BR mkostemp ()
|
|
is like
|
|
.BR mkstemp (),
|
|
with the difference that flags as for
|
|
.BR open (2)
|
|
may be specified in
|
|
.IR flags
|
|
(e.g.,
|
|
.BR O_APPEND ,
|
|
.BR O_SYNC ).
|
|
.SH "RETURN VALUE"
|
|
On success, these functions return the file descriptor
|
|
of the temporary file.
|
|
On error, \-1 is returned, and
|
|
.I errno
|
|
is set appropriately.
|
|
.SH ERRORS
|
|
.TP
|
|
.B EEXIST
|
|
Could not create a unique temporary filename.
|
|
Now the contents of \fItemplate\fP are undefined.
|
|
.TP
|
|
.B EINVAL
|
|
The last six characters of \fItemplate\fP were not XXXXXX.
|
|
Now \fItemplate\fP is unchanged.
|
|
.PP
|
|
These functions may also fail with any of the errors described for
|
|
.BR open (2).
|
|
.SH VERSIONS
|
|
.BR mkostemp ()
|
|
is available since glibc 2.7.
|
|
.SH "CONFORMING TO"
|
|
.BR mkstemp ():
|
|
4.3BSD, POSIX.1-2001.
|
|
.BR mkostemp ():
|
|
is a glibc extension.
|
|
.SH NOTES
|
|
The old behavior of creating a file with mode 0666 may be
|
|
a security risk, especially since other Unix flavors use 0600,
|
|
and somebody might overlook this detail when porting programs.
|
|
|
|
More generally, the POSIX specification of
|
|
.BR mkstemp ()
|
|
does not say anything
|
|
about file modes, so the application should make sure its
|
|
file mode creation mask (see
|
|
.BR umask (2))
|
|
is set appropriately before calling
|
|
.BR mkstemp ()
|
|
(and
|
|
.BR mkostemp ()).
|
|
|
|
The prototype for
|
|
.BR mktemp ()
|
|
is in
|
|
.I <unistd.h>
|
|
for libc4, libc5, glibc1; glibc2 follows POSIX.1 and has the prototype in
|
|
.IR <stdlib.h> .
|
|
.SH "SEE ALSO"
|
|
.BR mkdtemp (3),
|
|
.BR mktemp (3),
|
|
.BR tempnam (3),
|
|
.BR tmpfile (3),
|
|
.BR tmpnam (3)
|