Add a shared "port" directory for POSIX functions needed by multiple host tools ...
[reactos.git] / sdk / tools / port / mkstemps.c
1 /* Copyright (C) 1991, 1992, 1996, 1998 Free Software Foundation, Inc.
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 Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the 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 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
17 Boston, MA 02110-1301, USA.
18 */
19
20 #include <sys/types.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <errno.h>
24 #include <stdio.h>
25 #include <fcntl.h>
26
27 #ifdef _WIN32
28 #include <io.h>
29 #include <process.h>
30 #else
31 #include <unistd.h>
32 #include <sys/time.h>
33 #endif
34
35 /* We need to provide a type for gcc_uint64_t. */
36 #ifdef __GNUC__
37 __extension__ typedef unsigned long long gcc_uint64_t;
38 #else
39 typedef unsigned long gcc_uint64_t;
40 #endif
41
42 #ifndef TMP_MAX
43 #define TMP_MAX 16384
44 #endif
45
46 /* if O_BINARY is not defined, the system is probably not expecting any such flag */
47 #ifndef O_BINARY
48 #define O_BINARY 0
49 #endif
50
51 /*
52
53 @deftypefn Replacement int mkstemps (char *@var{template}, int @var{suffix_len})
54
55 Generate a unique temporary file name from @var{template}.
56 @var{template} has the form:
57
58 @example
59 @var{path}/ccXXXXXX@var{suffix}
60 @end example
61
62 @var{suffix_len} tells us how long @var{suffix} is (it can be zero
63 length). The last six characters of @var{template} before @var{suffix}
64 must be @samp{XXXXXX}; they are replaced with a string that makes the
65 filename unique. Returns a file descriptor open on the file for
66 reading and writing.
67
68 @end deftypefn
69
70 */
71
72 int
73 mkstemps (
74 char *template,
75 int suffix_len)
76 {
77 static const char letters[]
78 = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
79 static gcc_uint64_t value;
80 #ifdef HAVE_GETTIMEOFDAY
81 struct timeval tv;
82 #endif
83 char *XXXXXX;
84 size_t len;
85 int count;
86
87 len = strlen (template);
88
89 if ((int) len < 6 + suffix_len
90 || strncmp (&template[len - 6 - suffix_len], "XXXXXX", 6))
91 {
92 printf("wrong parameter\n");
93 return -1;
94 }
95
96 XXXXXX = &template[len - 6 - suffix_len];
97
98 #ifdef HAVE_GETTIMEOFDAY
99 /* Get some more or less random data. */
100 gettimeofday (&tv, NULL);
101 value += ((gcc_uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid ();
102 #else
103 value += getpid ();
104 #endif
105
106 for (count = 0; count < TMP_MAX; ++count)
107 {
108 gcc_uint64_t v = value;
109 int fd;
110
111 /* Fill in the random bits. */
112 XXXXXX[0] = letters[v % 62];
113 v /= 62;
114 XXXXXX[1] = letters[v % 62];
115 v /= 62;
116 XXXXXX[2] = letters[v % 62];
117 v /= 62;
118 XXXXXX[3] = letters[v % 62];
119 v /= 62;
120 XXXXXX[4] = letters[v % 62];
121 v /= 62;
122 XXXXXX[5] = letters[v % 62];
123
124 #ifdef VMS
125 fd = open (template, O_RDWR|O_CREAT|O_EXCL, 0600, "fop=tmd");
126 #else
127 fd = open (template, O_RDWR|O_CREAT|O_EXCL|O_BINARY, 0600);
128 #endif
129 if (fd >= 0)
130 /* The file does not exist. */
131 return fd;
132
133 /* This is a random value. It is only necessary that the next
134 TMP_MAX values generated by adding 7777 to VALUE are different
135 with (module 2^32). */
136 value += 7777;
137 }
138
139 /* We return the null string if we can't find a unique file name. */
140 template[0] = '\0';
141 return -1;
142 }