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