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guile/libguile/mkstemp.c
Andy Wingo 0e42886088 mkstemp uses O_BINARY
* libguile/mkstemp.c (mkstemp): Add O_BINARY.  Since temp files are
  empty at the beginning, we're not changing the behavior for reading
  files.  For writing files `newline' and ~% can add \r elements as
  needed.  So this is a reasonable thing to do, and it prevents mangling
  of temp files for the compiler.
2013-02-20 21:20:55 +01:00

129 lines
3.4 KiB
C

/* Copyright (C) 1991, 1992, 1996, 1998, 2001, 2006, 2013 Free Software Foundation, Inc.
This file is derived from mkstemps.c from the GNU Libiberty Library
which in turn is derived from 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., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "libguile/__scm.h"
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <errno.h>
#include <stdio.h>
#include <fcntl.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef __MINGW32__
#include <process.h>
#endif
#ifndef TMP_MAX
#define TMP_MAX 16384
#endif
/* We provide this prototype to avoid compiler warnings. If this ever
conflicts with a declaration in a system header file, we'll find
out, because we should include that header file here. */
int mkstemp (char *);
/* Generate a unique temporary file name from TEMPLATE.
TEMPLATE has the form:
<path>/ccXXXXXX
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[]
= "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
static scm_t_uint64 value;
#ifdef HAVE_GETTIMEOFDAY
struct timeval tv;
#endif
char *XXXXXX;
size_t len;
int count;
len = strlen (template);
if ((int) len < 6
|| strncmp (&template[len - 6], "XXXXXX", 6))
{
return -1;
}
XXXXXX = &template[len - 6];
#ifdef HAVE_GETTIMEOFDAY
/* Get some more or less random data. */
gettimeofday (&tv, NULL);
value += ((scm_t_uint64) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid ();
#else
value += getpid ();
#endif
for (count = 0; count < TMP_MAX; ++count)
{
scm_t_uint64 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|O_BINARY, 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;
}