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/* Copyright (C) 1999, 2001-2003, 2006 Free Software Foundation, Inc.
This file is part of the GNU C Library.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, see <http://www.gnu.org/licenses/>. */
/* Extracted from misc/mkdtemp.c and sysdeps/posix/tempname.c. */
#include <config.h>
/* Specification. */
#include "mkdtemp.h"
#include <errno.h>
#ifndef __set_errno
# define __set_errno(Val) errno = (Val)
#endif
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#ifndef TMP_MAX
# define TMP_MAX 238328
#endif
#include <unistd.h>
#if HAVE_GETTIMEOFDAY || _LIBC
# if HAVE_SYS_TIME_H || _LIBC
# include <sys/time.h>
# endif
#else
# if HAVE_TIME_H || _LIBC
# include <time.h>
# endif
#endif
#include <sys/stat.h>
#if !defined S_ISDIR && defined S_IFDIR
# define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
#endif
#if !S_IRUSR && S_IREAD
# define S_IRUSR S_IREAD
#endif
#if !S_IRUSR
# define S_IRUSR 00400
#endif
#if !S_IWUSR && S_IWRITE
# define S_IWUSR S_IWRITE
#endif
#if !S_IWUSR
# define S_IWUSR 00200
#endif
#if !S_IXUSR && S_IEXEC
# define S_IXUSR S_IEXEC
#endif
#if !S_IXUSR
# define S_IXUSR 00100
#endif
#ifdef __MINGW32__
# include <io.h>
#endif
#if !_LIBC
# define __getpid getpid
# define __gettimeofday gettimeofday
# define __mkdir mkdir
#endif
/* Use the widest available unsigned type if uint64_t is not
available. The algorithm below extracts a number less than 62**6
(approximately 2**35.725) from uint64_t, so ancient hosts where
uintmax_t is only 32 bits lose about 3.725 bits of randomness,
which is better than not having mkstemp at all. */
#if !defined UINT64_MAX && !defined uint64_t
# define uint64_t uintmax_t
#endif
/* These are the characters used in temporary filenames. */
static const char letters[] =
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
/* Generate a temporary file name based on TMPL. TMPL must match the
rules for mk[s]temp (i.e. end in "XXXXXX"). The name constructed
does not exist at the time of the call to __gen_tempname. TMPL is
overwritten with the result.
KIND is:
__GT_DIR: create a directory, which will be mode 0700.
We use a clever algorithm to get hard-to-predict names. */
static int
gen_tempname (char *tmpl)
{
int len;
char *XXXXXX;
static uint64_t value;
uint64_t random_time_bits;
unsigned int count;
int fd = -1;
int save_errno = errno;
/* A lower bound on the number of temporary files to attempt to
generate. The maximum total number of temporary file names that
can exist for a given template is 62**6. It should never be
necessary to try all these combinations. Instead if a reasonable
number of names is tried (we define reasonable as 62**3) fail to
give the system administrator the chance to remove the problems. */
#define ATTEMPTS_MIN (62 * 62 * 62)
/* The number of times to attempt to generate a temporary file. To
conform to POSIX, this must be no smaller than TMP_MAX. */
#if ATTEMPTS_MIN < TMP_MAX
unsigned int attempts = TMP_MAX;
#else
unsigned int attempts = ATTEMPTS_MIN;
#endif
len = strlen (tmpl);
if (len < 6 || strcmp (&tmpl[len - 6], "XXXXXX"))
{
__set_errno (EINVAL);
return -1;
}
/* This is where the Xs start. */
XXXXXX = &tmpl[len - 6];
/* Get some more or less random data. */
#ifdef RANDOM_BITS
RANDOM_BITS (random_time_bits);
#else
# if HAVE_GETTIMEOFDAY || _LIBC
{
struct timeval tv;
__gettimeofday (&tv, NULL);
random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;
}
# else
random_time_bits = time (NULL);
# endif
#endif
value += random_time_bits ^ __getpid ();
for (count = 0; count < attempts; value += 7777, ++count)
{
uint64_t v = value;
/* 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];
#ifdef MKDIR_TAKES_ONE_ARG
fd = mkdir (tmpl);
#else
fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR);
#endif
if (fd >= 0)
{
__set_errno (save_errno);
return fd;
}
else if (errno != EEXIST)
return -1;
}
/* We got out of the loop because we ran out of combinations to try. */
__set_errno (EEXIST);
return -1;
}
/* Generate a unique temporary directory from TEMPLATE.
The last six characters of TEMPLATE must be "XXXXXX";
they are replaced with a string that makes the filename unique.
The directory is created, mode 700, and its name is returned.
(This function comes from OpenBSD.) */
char *
mkdtemp (char *template)
{
if (gen_tempname (template))
return NULL;
else
return template;
}
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