1 /* Copyright (C) 1991, 1992, 1996, 1998, 2001, 2006 Free Software Foundation, Inc.
2 This file is derived from mkstemps.c from the GNU Libiberty Library
3 which in turn is derived from the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
18 Boston, MA 02110-1301, USA.
25 #include "libguile/__scm.h"
39 #ifdef HAVE_SYS_TIME_H
50 /* We provide this prototype to avoid compiler warnings. If this ever
51 conflicts with a declaration in a system header file, we'll find
52 out, because we should include that header file here. */
55 /* Generate a unique temporary file name from TEMPLATE.
57 TEMPLATE has the form:
61 The last six characters of TEMPLATE must be "XXXXXX"; they are
62 replaced with a string that makes the filename unique.
64 Returns a file descriptor open on the file for reading and writing. */
69 static const char letters[]
70 = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
71 static scm_t_uint64 value;
72 #ifdef HAVE_GETTIMEOFDAY
79 len = strlen (template);
82 || strncmp (&template[len - 6], "XXXXXX", 6))
87 XXXXXX = &template[len - 6];
89 #ifdef HAVE_GETTIMEOFDAY
90 /* Get some more or less random data. */
91 gettimeofday (&tv, NULL);
92 value += ((scm_t_uint64) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid ();
97 for (count = 0; count < TMP_MAX; ++count)
99 scm_t_uint64 v = value;
102 /* Fill in the random bits. */
103 XXXXXX[0] = letters[v % 62];
105 XXXXXX[1] = letters[v % 62];
107 XXXXXX[2] = letters[v % 62];
109 XXXXXX[3] = letters[v % 62];
111 XXXXXX[4] = letters[v % 62];
113 XXXXXX[5] = letters[v % 62];
115 fd = open (template, O_RDWR|O_CREAT|O_EXCL, 0600);
117 /* The file does not exist. */
120 /* This is a random value. It is only necessary that the next
121 TMP_MAX values generated by adding 7777 to VALUE are different
122 with (module 2^32). */
126 /* We return the null string if we can't find a unique file name. */