/* Copyright (C) 1991-2018 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

   <http://www.gnu.org/licenses/>.  */

#include <stdio.h>

#include <string.h>

static char tmpnam_buffer[L_tmpnam];

/* Generate a unique filename in P_tmpdir.

   This function is *not* thread safe!  */

char *

tmpnam (char *s)

{

  /* By using two buffers we manage to be thread safe in the case

     where S != NULL.  */

  char tmpbufmem[L_tmpnam];

  char *tmpbuf = s ?: tmpbufmem;

  /* In the following call we use the buffer pointed to by S if

     non-NULL although we don't know the size.  But we limit the size

     to L_tmpnam characters in any case.  */

  if (__builtin_expect (__path_search (tmpbuf, L_tmpnam, NULL, NULL, 0),

			0))

    return NULL;

  if (__glibc_unlikely (__gen_tempname (tmpbuf, 0, 0, __GT_NOCREATE)))

    return NULL;

  if (s == NULL)

    return (char *) memcpy (tmpnam_buffer, tmpbuf, L_tmpnam);

  return s;

}

link_warning (tmpnam,

	      "the use of `tmpnam' is dangerous, better use `mkstemp'")