rom/dos/namefromlock.c

   1 /*
   2     Copyright © 1995-2011, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Retrieve the full pathname from a lock.
   6     Lang: english
   7 */
   8 #include <proto/exec.h>
   9 #include "dos_intern.h"
  10
  11 #include <aros/debug.h>
  12
  13 /*****************************************************************************
  14
  15     NAME */
  16 #include <proto/dos.h>
  17
  18         AROS_LH3(BOOL, NameFromLock,
  19
  20 /*  SYNOPSIS */
  21         AROS_LHA(BPTR,   lock,   D1),
  22         AROS_LHA(STRPTR, buffer, D2),
  23         AROS_LHA(LONG,   length, D3),
  24
  25 /*  LOCATION */
  26         struct DosLibrary *, DOSBase, 67, Dos)
  27
  28 /*  FUNCTION
  29         Get the full path name associated with a lock to a file or
  30         directory into a user supplied buffer.
  31         If the lock is zero the buffer will be filled with "SYS:".
  32
  33     INPUTS
  34         lock   - Lock to file or directory or 0.
  35         buffer - Buffer to fill. Contains a NUL terminated string if
  36                  all went well.
  37         length - Size of the buffer in bytes.
  38
  39     RESULT
  40         !=0 if all went well, 0 in case of an error. IoErr() will
  41         give additional information in that case.
  42
  43 *****************************************************************************/
  44
  45 {
  46     AROS_LIBFUNC_INIT
  47
  48     /*
  49      * We could simply call namefrom_internal() with our lock. However this
  50      * causes prolems with Mount on SFS. Mount with a pattern (e. g. Mount DEVS:DOSDrivers/#?)
  51      * enters endless loop examining the same first file all times.
  52      * The problem occurs because Mount calls NameFromLock() on AnchorPath's ap_Current->an_Lock().
  53      * This results in calling Examine() on this lock.
  54      * SFS, in its turn, uses own extended form of a lock, and stores some information about current
  55      * search position in it. Calling Examine() on this lock, even with another FIB, causes search
  56      * position to be reset to the beginning of the directory.
  57      * This is unlikely a bug in Mount, because this code perfectly works on MorphOS without any
  58      * modifications. This is either:
  59      * a) A bug in SFS itself (unlikely, should have been noticed and fixed)
  60      * b) Wrong implementation of our NameFromLock().
  61      *
  62      * Duplicating a lock here is a brute-force workaround for this problem. When i have more time, i'll
  63      * pick up my old archive with MorphOS dos.library code, and check theirs implementation.
  64      *                                                                  Sonic
  65      */
  66     BOOL res;
  67     BPTR lock2;
  68
  69     if (lock == BNULL) {
  70         if (length > 5) {
  71             CopyMem("SYS:", buffer, 5);
  72             return DOSTRUE;
  73         } else {
  74             SetIoErr(ERROR_LINE_TOO_LONG);
  75             return DOSFALSE;
  76         }
  77     }
  78
  79
  80     lock2 = DupLock(lock);
  81     res = namefrom_internal(DOSBase, lock2, buffer, length);
  82     UnLock(lock2);
  83
  84     return res;
  85
  86     AROS_LIBFUNC_EXIT
  87 }