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252b5132 RH |
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 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, | |
16 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
17 | Boston, MA 02111-1307, USA. */ | |
18 | ||
19 | #ifdef HAVE_CONFIG_H | |
20 | #include "config.h" | |
21 | #endif | |
22 | ||
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" | |
39 | ||
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 | |
46 | ||
47 | #ifndef TMP_MAX | |
48 | #define TMP_MAX 16384 | |
49 | #endif | |
50 | ||
51 | /* Generate a unique temporary file name from TEMPLATE. | |
52 | ||
53 | TEMPLATE has the form: | |
54 | ||
55 | <path>/ccXXXXXX<suffix> | |
56 | ||
57 | SUFFIX_LEN tells us how long <suffix> is (it can be zero length). | |
58 | ||
59 | The last six characters of TEMPLATE before <suffix> must be "XXXXXX"; | |
60 | they are replaced with a string that makes the filename unique. | |
61 | ||
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; | |
67 | { | |
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; | |
77 | ||
78 | len = strlen (template); | |
79 | ||
80 | if ((int) len < 6 + suffix_len | |
81 | || strncmp (&template[len - 6 - suffix_len], "XXXXXX", 6)) | |
82 | { | |
83 | return -1; | |
84 | } | |
85 | ||
86 | XXXXXX = &template[len - 6 - suffix_len]; | |
87 | ||
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 | |
95 | ||
96 | for (count = 0; count < TMP_MAX; ++count) | |
97 | { | |
98 | gcc_uint64_t v = value; | |
99 | int fd; | |
100 | ||
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]; | |
113 | ||
114 | fd = open (template, O_RDWR|O_CREAT|O_EXCL, 0600); | |
115 | if (fd >= 0) | |
116 | /* The file does not exist. */ | |
117 | return fd; | |
118 | ||
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; | |
123 | } | |
124 | ||
125 | /* We return the null string if we can't find a unique file name. */ | |
126 | template[0] = '\0'; | |
127 | return -1; | |
128 | } |