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__ 42typedef unsigned long long gcc_uint64_t; 43#else 44typedef 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. */ 63int 64mkstemps (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} 129