glibc/stdio-common/tmpfile.c

78 lines
2.1 KiB
C

/* Open a stdio stream on an anonymous temporary file. Generic/POSIX version.
Copyright (C) 1991-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <iolibio.h>
#define __fdopen _IO_fdopen
#ifndef tmpfile
# define tmpfile __new_tmpfile
#endif
/* This returns a new stream opened on a temporary file (generated
by tmpnam). The file is opened with mode "w+b" (binary read/write).
If we couldn't generate a unique filename or the file couldn't
be opened, NULL is returned. */
FILE *
tmpfile (void)
{
int fd;
FILE *f;
int flags = 0;
#ifdef FLAGS
flags = FLAGS;
#endif
/* First try a system specific method. */
fd = __gen_tempfd (flags);
if (fd < 0)
{
char buf[FILENAME_MAX];
if (__path_search (buf, sizeof buf, NULL, "tmpf", 0))
return NULL;
fd = __gen_tempname (buf, 0, flags, __GT_FILE);
if (fd < 0)
return NULL;
/* Note that this relies on the Unix semantics that
a file is not really removed until it is closed. */
(void) __unlink (buf);
}
if ((f = __fdopen (fd, "w+b")) == NULL)
__close (fd);
return f;
}
#if !defined O_LARGEFILE || O_LARGEFILE == 0
weak_alias (__new_tmpfile, tmpfile64)
#endif
#ifndef FLAGS /* Not for tmpfile64. */
# undef tmpfile
# include <shlib-compat.h>
versioned_symbol (libc, __new_tmpfile, tmpfile, GLIBC_2_1);
#endif