libs/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 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 St, Fifth Floor,
  17    Boston, MA 02110-1301, USA  */
  18
  19 #include "config.h"
  20 #include "wine/port.h"
  21
  22 #include <sys/types.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <errno.h>
  26 #include <stdio.h>
  27 #include <fcntl.h>
  28 #ifdef HAVE_UNISTD_H
  29 #include <unistd.h>
  30 #endif
  31 #ifdef HAVE_SYS_TIME_H
  32 #include <sys/time.h>
  33 #endif
  34
  35 #ifndef TMP_MAX
  36 #define TMP_MAX 16384
  37 #endif
  38
  39 /*
  40
  41 @deftypefn Replacement int mkstemps (char *@var{template}, int @var{suffix_len})
  42
  43 Generate a unique temporary file name from @var{template}.
  44 @var{template} has the form:
  45
  46 @example
  47    @var{path}/ccXXXXXX@var{suffix}
  48 @end example
  49
  50 @var{suffix_len} tells us how long @var{suffix} is (it can be zero
  51 length).  The last six characters of @var{template} before @var{suffix}
  52 must be @samp{XXXXXX}; they are replaced with a string that makes the
  53 filename unique.  Returns a file descriptor open on the file for
  54 reading and writing.
  55
  56 @end deftypefn
  57
  58 */
  59
  60 int
  61 mkstemps (
  62      char *template,
  63      int suffix_len)
  64 {
  65   static const char letters[]
  66     = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
  67   static unsigned __int64 value;
  68   char *XXXXXX;
  69   size_t len;
  70   int count;
  71
  72   len = strlen (template);
  73
  74   if ((int) len < 6 + suffix_len
  75       || strncmp (&template[len - 6 - suffix_len], "XXXXXX", 6))
  76     {
  77       return -1;
  78     }
  79
  80   XXXXXX = &template[len - 6 - suffix_len];
  81
  82 #ifndef _WIN32
  83   {
  84       struct timeval tv;
  85       gettimeofday( &tv, NULL );
  86       value += ((unsigned __int64) tv.tv_usec << 16) ^ tv.tv_sec;
  87   }
  88 #endif
  89   value += getpid();
  90
  91   for (count = 0; count < TMP_MAX; ++count)
  92     {
  93       unsigned __int64 v = value;
  94       int fd;
  95
  96       /* Fill in the random bits.  */
  97       XXXXXX[0] = letters[v % 62];
  98       v /= 62;
  99       XXXXXX[1] = letters[v % 62];
 100       v /= 62;
 101       XXXXXX[2] = letters[v % 62];
 102       v /= 62;
 103       XXXXXX[3] = letters[v % 62];
 104       v /= 62;
 105       XXXXXX[4] = letters[v % 62];
 106       v /= 62;
 107       XXXXXX[5] = letters[v % 62];
 108
 109       fd = open (template, O_RDWR|O_CREAT|O_EXCL, 0600);
 110       if (fd >= 0)
 111         /* The file does not exist.  */
 112         return fd;
 113
 114       /* This is a random value.  It is only necessary that the next
 115          TMP_MAX values generated by adding 7777 to VALUE are different
 116          with (module 2^32).  */
 117       value += 7777;
 118     }
 119
 120   return -1;
 121 }