rom/dos/parentoffh.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Lock the directory a file is located in
   6     Lang: english
   7 */
   8 #include "dos_intern.h"
   9 #include <dos/dosasl.h>
  10 #include <proto/exec.h>
  11
  12 /*****************************************************************************
  13
  14     NAME */
  15 #include <proto/dos.h>
  16
  17         AROS_LH1(BPTR, ParentOfFH,
  18
  19 /*  SYNOPSIS */
  20         AROS_LHA(BPTR, fh, D1),
  21
  22 /*  LOCATION */
  23         struct DosLibrary *, DOSBase, 64, Dos)
  24
  25 /*  FUNCTION
  26         Lock the directory a file is located in.
  27
  28     INPUTS
  29         fh  - Filhandle of which you want to obtain the parent
  30
  31     RESULT
  32         lock - Lock on the parent directory of the filehandle or
  33                NULL for failure.
  34
  35
  36     NOTES
  37
  38     EXAMPLE
  39
  40     BUGS
  41
  42     SEE ALSO
  43         Lock(), UnLock(), Parent()
  44
  45     INTERNALS
  46
  47 *****************************************************************************/
  48 {
  49     AROS_LIBFUNC_INIT
  50
  51     BPTR    lock = MKBADDR(NULL);
  52     LONG    success = DOSFALSE;
  53     char *  Buffer = NULL;
  54     LONG    Buffersize = 256;
  55     LONG    Attempts = 1;
  56
  57     #define DEF_BUFSIZESTEP 128
  58
  59     if (fh != NULL)
  60     {
  61         /* Attempt to get the string of the file fh */
  62         while ((DOSFALSE == success) && (Attempts <= 5))
  63         {
  64             Buffer = (char *) AllocMem(Buffersize, MEMF_CLEAR);
  65
  66             if (NULL ==  Buffer)
  67                 return NULL;
  68
  69             success = NameFromFH(fh, Buffer, Buffersize);
  70
  71             /* did it fail with a buffer overflow?? */
  72             if (DOSFALSE == success)
  73             {
  74                 if (ERROR_BUFFER_OVERFLOW == IoErr())
  75                 {
  76                     Attempts++;
  77                     FreeMem(Buffer, Buffersize);
  78                     Buffersize += DEF_BUFSIZESTEP;
  79                 }
  80                 else /* another error occured -> exit */
  81                 {
  82                     FreeMem(Buffer, Buffersize);
  83                     return NULL;
  84                 }
  85             }
  86
  87         } /* while ((DOSFALSE == success) && (Attempts <= 5)) */
  88
  89         if (DOSTRUE == success)
  90         {
  91             char * PP = PathPart(Buffer); /* get the path part of the file */
  92
  93             *PP = '\0';
  94
  95             lock = Lock (Buffer, SHARED_LOCK);
  96         }
  97
  98         FreeMem(Buffer, Buffersize);
  99
 100     } /* if (fh != NULL) */
 101
 102     return lock;
 103
 104     AROS_LIBFUNC_EXIT
 105
 106 } /* ParentOfFH */