compiler/clib/mkstemp.c

   1 /*
   2     Copyright © 1995-2003, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     POSIX function mkstemp().
   6 */
   7
   8 #include <string.h>
   9 #include <errno.h>
  10 #include <fcntl.h>
  11 #include <proto/dos.h>
  12
  13 /*****************************************************************************
  14
  15     NAME */
  16 #include <stdlib.h>
  17
  18         int mkstemp(
  19
  20 /*  SYNOPSIS */
  21         char *template)
  22
  23 /*  FUNCTION
  24
  25     INPUTS
  26         A template that must end with 'XXXXXX'
  27
  28     RESULT
  29
  30     NOTES
  31
  32     EXAMPLE
  33
  34     BUGS
  35
  36     SEE ALSO
  37
  38     INTERNALS
  39
  40 ******************************************************************************/
  41 {
  42     char *c = template + strlen(template);
  43     char *c_start;
  44     BPTR  lock;
  45     int ctr = 0;
  46     static char filename_letters[] = "01234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZFILLTO64";
  47
  48     while (c > template && *--c == 'X') {
  49       ctr++;
  50     }
  51
  52     if (ctr < 6) {
  53       return EINVAL;
  54     }
  55
  56     c++;
  57     c_start = c;
  58
  59     while (1) {
  60         while (*c) {
  61             *c = filename_letters[rand() & 0x3F];
  62             c++;
  63         }
  64         if (!(lock = Lock(template, ACCESS_READ))) {
  65             int fd = open(template, O_CREAT|O_EXCL);
  66             if (fd > 0)
  67                 return fd;
  68         }
  69         UnLock(lock);
  70         c = c_start;
  71         /*
  72          * Try around 1000 filenames and then give up.
  73          */
  74         if (++ctr > 1000)
  75             break;
  76     }
  77
  78     return EEXIST;
  79
  80 } /* mkstemp() */