1 /* Copyright (C) 2001 Free Software Foundation, Inc.
2 Written by Werner Lemberg (wl@gnu.org)
4 This file is part of groff.
6 groff is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 2, or (at your option) any later
11 groff is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License along
17 with groff; see the file COPYING. If not, write to the Free Software
18 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
21 /* This file is heavily based on the function __gen_tempname() in the
22 file tempname.c which is part of the fileutils package. */
24 /* $DragonFly: src/contrib/groff/src/libs/libgroff/Attic/tmpname.cc,v 1.2 2003/11/03 22:51:48 dillon Exp $ */
37 # define TMP_MAX 238328
41 # include <sys/time.h>
44 #ifdef HAVE_GETTIMEOFDAY
45 #ifdef NEED_DECLARATION_GETTIMEOFDAY
47 int gettimeofday(struct timeval *, void *);
56 /* Use the widest available unsigned type if uint64_t is not
57 available. The algorithm below extracts a number less than 62**6
58 (approximately 2**35.725) from uint64_t, so ancient hosts where
59 uintmax_t is only 32 bits lose about 3.725 bits of randomness,
60 which is better than not having mkstemp at all. */
62 #if !defined UINT64_MAX && !defined uint64_t
63 # define uint64_t uintmax_t
67 /* These are the characters used in temporary filenames. */
68 static const char letters[] =
69 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
71 int gen_tempname(char *tmpl, int dir)
73 static uint64_t value;
75 size_t len = strlen(tmpl);
76 if (len < 6 || strcmp(&tmpl[len - 6], "XXXXXX"))
77 return -1; /* EINVAL */
79 /* This is where the Xs start. */
80 char *XXXXXX = &tmpl[len - 6];
82 /* Get some more or less random data. */
85 gettimeofday(&tv, NULL);
86 uint64_t random_time_bits = ((uint64_t)tv.tv_usec << 16) ^ tv.tv_sec;
88 uint64_t random_time_bits = time(NULL);
90 value += random_time_bits ^ getpid();
92 for (int count = 0; count < TMP_MAX; value += 7777, ++count) {
95 /* Fill in the random bits. */
96 XXXXXX[0] = letters[v % 62];
98 XXXXXX[1] = letters[v % 62];
100 XXXXXX[2] = letters[v % 62];
102 XXXXXX[3] = letters[v % 62];
104 XXXXXX[4] = letters[v % 62];
106 XXXXXX[5] = letters[v % 62];
108 int fd = dir ? mkdir(tmpl, S_IRUSR | S_IWUSR | S_IXUSR)
109 : open(tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
113 else if (errno != EEXIST)
117 /* We got out of the loop because we ran out of combinations to try. */
118 return -1; /* EEXIST */