1 /* Copyright (C) 1991, 1992, 1996, 1998, 2004 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., 51 Franklin Street - Fifth Floor, 17 Boston, MA 02110-1301, USA. */ 18 19 #ifdef HAVE_CONFIG_H 20 #include "config.h" 21 #endif 22 23 #include <sys/types.h> 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 #elif HAVE_TIME_H 39 #include <time.h> 40 #endif 41 #include "ansidecl.h" 42 43 /* We need to provide a type for gcc_uint64_t. */ 44 #ifdef __GNUC__ 45 __extension__ typedef unsigned long long gcc_uint64_t; 46 #else 47 typedef unsigned long gcc_uint64_t; 48 #endif 49 50 #ifndef TMP_MAX 51 #define TMP_MAX 16384 52 #endif 53 54 #ifndef O_BINARY 55 # define O_BINARY 0 56 #endif 57 58 /* 59 60 @deftypefn Replacement int mkstemps (char *@var{pattern}, int @var{suffix_len}) 61 62 Generate a unique temporary file name from @var{pattern}. 63 @var{pattern} has the form: 64 65 @example 66 @var{path}/ccXXXXXX@var{suffix} 67 @end example 68 69 @var{suffix_len} tells us how long @var{suffix} is (it can be zero 70 length). The last six characters of @var{pattern} before @var{suffix} 71 must be @samp{XXXXXX}; they are replaced with a string that makes the 72 filename unique. Returns a file descriptor open on the file for 73 reading and writing. 74 75 @end deftypefn 76 77 */ 78 79 int 80 mkstemps (char *pattern, int suffix_len) 81 { 82 static const char letters[] 83 = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; 84 static gcc_uint64_t value; 85 #ifdef HAVE_GETTIMEOFDAY 86 struct timeval tv; 87 #endif 88 char *XXXXXX; 89 size_t len; 90 int count; 91 92 len = strlen (pattern); 93 94 if ((int) len < 6 + suffix_len 95 || strncmp (&pattern[len - 6 - suffix_len], "XXXXXX", 6)) 96 { 97 return -1; 98 } 99 100 XXXXXX = &pattern[len - 6 - suffix_len]; 101 102 #ifdef HAVE_GETTIMEOFDAY 103 /* Get some more or less random data. */ 104 gettimeofday (&tv, NULL); 105 value += ((gcc_uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid (); 106 #else 107 value += getpid (); 108 #endif 109 110 for (count = 0; count < TMP_MAX; ++count) 111 { 112 gcc_uint64_t v = value; 113 int fd; 114 115 /* Fill in the random bits. */ 116 XXXXXX[0] = letters[v % 62]; 117 v /= 62; 118 XXXXXX[1] = letters[v % 62]; 119 v /= 62; 120 XXXXXX[2] = letters[v % 62]; 121 v /= 62; 122 XXXXXX[3] = letters[v % 62]; 123 v /= 62; 124 XXXXXX[4] = letters[v % 62]; 125 v /= 62; 126 XXXXXX[5] = letters[v % 62]; 127 128 fd = open (pattern, O_BINARY|O_RDWR|O_CREAT|O_EXCL, 0600); 129 if (fd >= 0) 130 /* The file does not exist. */ 131 return fd; 132 if (errno != EEXIST 133 #ifdef EISDIR 134 && errno != EISDIR 135 #endif 136 ) 137 /* Fatal error (EPERM, ENOSPC etc). Doesn't make sense to loop. */ 138 break; 139 140 /* This is a random value. It is only necessary that the next 141 TMP_MAX values generated by adding 7777 to VALUE are different 142 with (module 2^32). */ 143 value += 7777; 144 } 145 146 /* We return the null string if we can't find a unique file name. */ 147 pattern[0] = '\0'; 148 return -1; 149 } 150
