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/* Copyright (C) 1991, 1992, 1996, 1998 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/time.h>
/* Generate a unique temporary file name from TEMPLATE.
The last six characters of TEMPLATE must be "XXXXXX";
they are replaced with a string that makes the filename unique.
Returns a file descriptor open on the file for reading and writing. */
int
mkstemp (template)
char *template;
{
static const char letters[62]
= "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
static uint64_t value;
struct timeval tv;
char *XXXXXX;
size_t len;
int count;
len = strlen (template);
if (len < 6 || strcmp (&template[len - 6], "XXXXXX"))
{
__set_errno (EINVAL);
return -1;
}
/* This is where the Xs start. */
XXXXXX = &template[len - 6];
/* Get some more or less random data. */
__gettimeofday (&tv, NULL);
value += ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid ();
for (count = 0; count < TMP_MAX; ++count)
{
uint64_t v = value;
int fd;
/* Fill in the random bits. */
XXXXXX[0] = letters[v % 62];
v /= 62;
XXXXXX[1] = letters[v % 62];
v /= 62;
XXXXXX[2] = letters[v % 62];
v /= 62;
XXXXXX[3] = letters[v % 62];
v /= 62;
XXXXXX[4] = letters[v % 62];
v /= 62;
XXXXXX[5] = letters[v % 62];
fd = open (template, O_RDWR|O_CREAT|O_EXCL, 0600);
if (fd >= 0)
/* The file does not exist. */
return fd;
/* This is a random value. It is only necessary that the next
TMP_MAX values generated by adding 7777 to VALUE are different
with (module 2^32). */
value += 7777;
}
/* We return the null string if we can't find a unique file name. */
template[0] = '\0';
return -1;
}
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