* libbfd.c (bfd_read): Check result of read against desired result
[binutils.git] / libiberty / mkstemps.c
blob16c16a23263a2b77a0065494f7ea32a0d2c3e0a1
1 /* Copyright (C) 1991, 1992, 1996, 1998 Free Software Foundation, Inc.
2 This file is derived from mkstemp.c from the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Library General Public License for more details.
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If not,
16 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 Boston, MA 02111-1307, USA. */
19 #ifdef HAVE_CONFIG_H
20 #include "config.h"
21 #endif
23 #ifdef HAVE_STDLIB_H
24 #include <stdlib.h>
25 #endif
26 #ifdef HAVE_STRING_H
27 #include <string.h>
28 #endif
29 #include <errno.h>
30 #include <stdio.h>
31 #include <fcntl.h>
32 #ifdef HAVE_UNISTD_H
33 #include <unistd.h>
34 #endif
35 #ifdef HAVE_SYS_TIME_H
36 #include <sys/time.h>
37 #endif
38 #include "ansidecl.h"
40 /* We need to provide a type for gcc_uint64_t. */
41 #ifdef __GNUC__
42 typedef unsigned long long gcc_uint64_t;
43 #else
44 typedef unsigned long gcc_uint64_t;
45 #endif
47 #ifndef TMP_MAX
48 #define TMP_MAX 16384
49 #endif
51 /* Generate a unique temporary file name from TEMPLATE.
53 TEMPLATE has the form:
55 <path>/ccXXXXXX<suffix>
57 SUFFIX_LEN tells us how long <suffix> is (it can be zero length).
59 The last six characters of TEMPLATE before <suffix> must be "XXXXXX";
60 they are replaced with a string that makes the filename unique.
62 Returns a file descriptor open on the file for reading and writing. */
63 int
64 mkstemps (template, suffix_len)
65 char *template;
66 int suffix_len;
68 static const char letters[]
69 = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
70 static gcc_uint64_t value;
71 #ifdef HAVE_GETTIMEOFDAY
72 struct timeval tv;
73 #endif
74 char *XXXXXX;
75 size_t len;
76 int count;
78 len = strlen (template);
80 if ((int) len < 6 + suffix_len
81 || strncmp (&template[len - 6 - suffix_len], "XXXXXX", 6))
83 return -1;
86 XXXXXX = &template[len - 6 - suffix_len];
88 #ifdef HAVE_GETTIMEOFDAY
89 /* Get some more or less random data. */
90 gettimeofday (&tv, NULL);
91 value += ((gcc_uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid ();
92 #else
93 value += getpid ();
94 #endif
96 for (count = 0; count < TMP_MAX; ++count)
98 gcc_uint64_t v = value;
99 int fd;
101 /* Fill in the random bits. */
102 XXXXXX[0] = letters[v % 62];
103 v /= 62;
104 XXXXXX[1] = letters[v % 62];
105 v /= 62;
106 XXXXXX[2] = letters[v % 62];
107 v /= 62;
108 XXXXXX[3] = letters[v % 62];
109 v /= 62;
110 XXXXXX[4] = letters[v % 62];
111 v /= 62;
112 XXXXXX[5] = letters[v % 62];
114 fd = open (template, O_RDWR|O_CREAT|O_EXCL, 0600);
115 if (fd >= 0)
116 /* The file does not exist. */
117 return fd;
119 /* This is a random value. It is only necessary that the next
120 TMP_MAX values generated by adding 7777 to VALUE are different
121 with (module 2^32). */
122 value += 7777;
125 /* We return the null string if we can't find a unique file name. */
126 template[0] = '\0';
127 return -1;