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25319993 | 1 | /* Copyright (C) 1991, 1992, 1996, 1998, 2004 Free Software Foundation, Inc. |
252b5132 RH |
2 | This file is derived from mkstemp.c from the GNU C Library. |
3 | ||
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. | |
8 | ||
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. | |
13 | ||
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, | |
979c05d3 NC |
16 | write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, |
17 | Boston, MA 02110-1301, USA. */ | |
252b5132 RH |
18 | |
19 | #ifdef HAVE_CONFIG_H | |
20 | #include "config.h" | |
21 | #endif | |
22 | ||
b1233257 | 23 | #include <sys/types.h> |
252b5132 RH |
24 | #ifdef HAVE_STDLIB_H |
25 | #include <stdlib.h> | |
26 | #endif | |
27 | #ifdef HAVE_STRING_H | |
28 | #include <string.h> | |
29 | #endif | |
30 | #include <errno.h> | |
31 | #include <stdio.h> | |
32 | #include <fcntl.h> | |
33 | #ifdef HAVE_UNISTD_H | |
34 | #include <unistd.h> | |
35 | #endif | |
36 | #ifdef HAVE_SYS_TIME_H | |
37 | #include <sys/time.h> | |
38 | #endif | |
39 | #include "ansidecl.h" | |
40 | ||
41 | /* We need to provide a type for gcc_uint64_t. */ | |
42 | #ifdef __GNUC__ | |
eb383413 | 43 | __extension__ typedef unsigned long long gcc_uint64_t; |
252b5132 RH |
44 | #else |
45 | typedef unsigned long gcc_uint64_t; | |
46 | #endif | |
47 | ||
48 | #ifndef TMP_MAX | |
49 | #define TMP_MAX 16384 | |
50 | #endif | |
51 | ||
ba19b94f | 52 | /* |
252b5132 | 53 | |
abf6a75b | 54 | @deftypefn Replacement int mkstemps (char *@var{pattern}, int @var{suffix_len}) |
252b5132 | 55 | |
abf6a75b DD |
56 | Generate a unique temporary file name from @var{pattern}. |
57 | @var{pattern} has the form: | |
ba19b94f DD |
58 | |
59 | @example | |
5d852400 | 60 | @var{path}/ccXXXXXX@var{suffix} |
ba19b94f DD |
61 | @end example |
62 | ||
5d852400 | 63 | @var{suffix_len} tells us how long @var{suffix} is (it can be zero |
abf6a75b | 64 | length). The last six characters of @var{pattern} before @var{suffix} |
5d852400 | 65 | must be @samp{XXXXXX}; they are replaced with a string that makes the |
ba19b94f DD |
66 | filename unique. Returns a file descriptor open on the file for |
67 | reading and writing. | |
252b5132 | 68 | |
ba19b94f | 69 | @end deftypefn |
252b5132 | 70 | |
ba19b94f | 71 | */ |
252b5132 | 72 | |
252b5132 | 73 | int |
abf6a75b | 74 | mkstemps (char *pattern, int suffix_len) |
252b5132 RH |
75 | { |
76 | static const char letters[] | |
77 | = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; | |
78 | static gcc_uint64_t value; | |
79 | #ifdef HAVE_GETTIMEOFDAY | |
80 | struct timeval tv; | |
81 | #endif | |
82 | char *XXXXXX; | |
83 | size_t len; | |
84 | int count; | |
85 | ||
abf6a75b | 86 | len = strlen (pattern); |
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87 | |
88 | if ((int) len < 6 + suffix_len | |
abf6a75b | 89 | || strncmp (&pattern[len - 6 - suffix_len], "XXXXXX", 6)) |
252b5132 RH |
90 | { |
91 | return -1; | |
92 | } | |
93 | ||
abf6a75b | 94 | XXXXXX = &pattern[len - 6 - suffix_len]; |
252b5132 RH |
95 | |
96 | #ifdef HAVE_GETTIMEOFDAY | |
97 | /* Get some more or less random data. */ | |
98 | gettimeofday (&tv, NULL); | |
99 | value += ((gcc_uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid (); | |
100 | #else | |
101 | value += getpid (); | |
102 | #endif | |
103 | ||
104 | for (count = 0; count < TMP_MAX; ++count) | |
105 | { | |
106 | gcc_uint64_t v = value; | |
107 | int fd; | |
108 | ||
109 | /* Fill in the random bits. */ | |
110 | XXXXXX[0] = letters[v % 62]; | |
111 | v /= 62; | |
112 | XXXXXX[1] = letters[v % 62]; | |
113 | v /= 62; | |
114 | XXXXXX[2] = letters[v % 62]; | |
115 | v /= 62; | |
116 | XXXXXX[3] = letters[v % 62]; | |
117 | v /= 62; | |
118 | XXXXXX[4] = letters[v % 62]; | |
119 | v /= 62; | |
120 | XXXXXX[5] = letters[v % 62]; | |
121 | ||
abf6a75b | 122 | fd = open (pattern, O_RDWR|O_CREAT|O_EXCL, 0600); |
252b5132 RH |
123 | if (fd >= 0) |
124 | /* The file does not exist. */ | |
125 | return fd; | |
126 | ||
127 | /* This is a random value. It is only necessary that the next | |
128 | TMP_MAX values generated by adding 7777 to VALUE are different | |
129 | with (module 2^32). */ | |
130 | value += 7777; | |
131 | } | |
132 | ||
133 | /* We return the null string if we can't find a unique file name. */ | |
abf6a75b | 134 | pattern[0] = '\0'; |
252b5132 RH |
135 | return -1; |
136 | } |