compiler/posixc/mkstemp.c

   1 /*
   2     Copyright © 1995-2012, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     POSIX.1-2008 function mkstemp().
   6 */
   7 #include <string.h>
   8 #include <errno.h>
   9 #include <fcntl.h>
  10 #include <proto/dos.h>
  11
  12 #include "__upath.h"
  13
  14 /*****************************************************************************
  15
  16     NAME */
  17 #include <stdlib.h>
  18
  19         int mkstemp(
  20
  21 /*  SYNOPSIS */
  22         char *template)
  23
  24 /*  FUNCTION
  25
  26     INPUTS
  27     A template that must end with 'XXXXXX'
  28
  29     RESULT
  30     A file descriptor of opened temporary file or -1 on error.
  31
  32     NOTES
  33
  34     EXAMPLE
  35
  36     BUGS
  37
  38     SEE ALSO
  39
  40     INTERNALS
  41
  42 ******************************************************************************/
  43 {
  44     char *c = template + strlen(template);
  45     char *c_start;
  46     BPTR  lock= BNULL;
  47     int ctr = 0;
  48     const char filename_letters[] = "01234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZFILLTO64";
  49     const char *atemplate;
  50
  51     while (c > template && *--c == 'X') {
  52         ctr++;
  53     }
  54
  55     if (ctr < 6) {
  56         errno = EINVAL;
  57         return -1;
  58     }
  59
  60     c++;
  61     c_start = c;
  62
  63     while (1) {
  64         while (*c) {
  65             *c = filename_letters[rand() & 0x3F];
  66             c++;
  67         }
  68
  69         atemplate = __path_u2a(template);
  70         if(!atemplate)
  71             return -1;
  72         if (!(lock = Lock(atemplate, ACCESS_READ))) {
  73             int fd = open(template, O_WRITE|O_CREAT|O_EXCL);
  74             if (fd > 0)
  75                 return fd;
  76         }
  77         UnLock(lock);
  78         c = c_start;
  79         /*
  80          * Try around 1000 filenames and then give up.
  81          */
  82         if (++ctr > 1000)
  83             break;
  84     }
  85
  86     errno = EEXIST;
  87     return -1;
  88
  89 } /* mkstemp() */