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 #ifdef HAVE_PROCESS_H
  35 #include <process.h>
  36 #endif
  37
  38 /* We need to provide a type for gcc_uint64_t.  */
  39 #ifdef __GNUC__
  40 __extension__ typedef unsigned long long gcc_uint64_t;
  41 #else
  42 typedef unsigned long gcc_uint64_t;
  43 #endif
  44
  45 #ifndef TMP_MAX
  46 #define TMP_MAX 16384
  47 #endif
  48
  49 /*
  50
  51 @deftypefn Replacement int mkstemps (char *@var{template}, int @var{suffix_len})
  52
  53 Generate a unique temporary file name from @var{template}.
  54 @var{template} has the form:
  55
  56 @example
  57    @var{path}/ccXXXXXX@var{suffix}
  58 @end example
  59
  60 @var{suffix_len} tells us how long @var{suffix} is (it can be zero
  61 length).  The last six characters of @var{template} before @var{suffix}
  62 must be @samp{XXXXXX}; they are replaced with a string that makes the
  63 filename unique.  Returns a file descriptor open on the file for
  64 reading and writing.
  65
  66 @end deftypefn
  67
  68 */
  69
  70 int
  71 mkstemps (
  72      char *template,
  73      int suffix_len)
  74 {
  75   static const char letters[]
  76     = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
  77   static gcc_uint64_t value;
  78 #ifdef HAVE_GETTIMEOFDAY
  79   struct timeval tv;
  80 #endif
  81   char *XXXXXX;
  82   size_t len;
  83   int count;
  84
  85   len = strlen (template);
  86
  87   if ((int) len < 6 + suffix_len
  88       || strncmp (&template[len - 6 - suffix_len], "XXXXXX", 6))
  89     {
  90       return -1;
  91     }
  92
  93   XXXXXX = &template[len - 6 - suffix_len];
  94
  95 #ifdef HAVE_GETTIMEOFDAY
  96   /* Get some more or less random data.  */
  97   gettimeofday (&tv, NULL);
  98   value += ((gcc_uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid ();
  99 #else
 100   value += getpid ();
 101 #endif
 102
 103   for (count = 0; count < TMP_MAX; ++count)
 104     {
 105       gcc_uint64_t v = value;
 106       int fd;
 107
 108       /* Fill in the random bits.  */
 109       XXXXXX[0] = letters[v % 62];
 110       v /= 62;
 111       XXXXXX[1] = letters[v % 62];
 112       v /= 62;
 113       XXXXXX[2] = letters[v % 62];
 114       v /= 62;
 115       XXXXXX[3] = letters[v % 62];
 116       v /= 62;
 117       XXXXXX[4] = letters[v % 62];
 118       v /= 62;
 119       XXXXXX[5] = letters[v % 62];
 120
 121 #ifdef VMS
 122       fd = open (template, O_RDWR|O_CREAT|O_EXCL, 0600, "fop=tmd");
 123 #else
 124       fd = open (template, O_RDWR|O_CREAT|O_EXCL, 0600);
 125 #endif
 126       if (fd >= 0)
 127         /* The file does not exist.  */
 128         return fd;
 129
 130       /* This is a random value.  It is only necessary that the next
 131          TMP_MAX values generated by adding 7777 to VALUE are different
 132          with (module 2^32).  */
 133       value += 7777;
 134     }
 135
 136   /* We return the null string if we can't find a unique file name.  */
 137   template[0] = '\0';
 138   return -1;
 139 }