rom/dos/changemode.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Change the mode of a filehandle or -lock.
   6     Lang: English
   7 */
   8 #include <proto/exec.h>
   9 #include <dos/dosextens.h>
  10 #include <dos/filesystem.h>
  11 #include "dos_intern.h"
  12
  13 /*****************************************************************************
  14
  15     NAME */
  16 #include <proto/dos.h>
  17
  18         AROS_LH3(BOOL, ChangeMode,
  19
  20 /*  SYNOPSIS */
  21         AROS_LHA(ULONG, type,    D1),
  22         AROS_LHA(BPTR,  object,  D2),
  23         AROS_LHA(ULONG, newmode, D3),
  24
  25 /*  LOCATION */
  26         struct DosLibrary *, DOSBase, 75, Dos)
  27
  28 /*  FUNCTION
  29         Try to change the mode used by a lock or filehandle.
  30
  31     INPUTS
  32         type    - CHANGE_FH or CHANGE_LOCK.
  33         object  - Filehandle or lock.
  34         newmode - New mode (see <dos/dos.h>).
  35
  36     RESULT
  37         != 0 if all went well, otherwise 0. IoErr() gives additional
  38         information in the latter case.
  39
  40     NOTES
  41         Since filehandles and locks are identical under AROS the type
  42         argument is ignored.
  43
  44     EXAMPLE
  45
  46     BUGS
  47
  48     SEE ALSO
  49
  50     INTERNALS
  51
  52 *****************************************************************************/
  53 {
  54     AROS_LIBFUNC_INIT
  55
  56     /* Get pointer to filehandle */
  57     struct FileHandle *fh = (struct FileHandle *)BADDR(object);
  58
  59     /* Get pointer to I/O request. Use stackspace for now. */
  60     struct IOFileSys iofs;
  61
  62     /* Convert Open() and Lock() constants to filehandler flags. */
  63     ULONG newflags, mask;
  64
  65     if(newmode == MODE_OLDFILE || newmode == MODE_READWRITE ||
  66        newmode == ACCESS_READ)
  67     {
  68         newflags = 0;
  69         mask     = FMF_LOCK;
  70     }
  71     else if(newmode == MODE_NEWFILE || newmode == ACCESS_WRITE)
  72     {
  73         newflags = FMF_LOCK;
  74         mask     = FMF_LOCK;
  75     }
  76     else
  77     {
  78         if (newmode & FMF_APPEND)
  79         {
  80             /* See if the handler supports FSA_SEEK */
  81             if (!(fh->fh_Flags & FHF_APPEND) && Seek(MKBADDR(fh), 0, OFFSET_END) != -1)
  82             {
  83                 /* if so then set the proper flag in the FileHandle struct */
  84                  fh->fh_Flags |= FHF_APPEND;
  85             }
  86         }
  87         else
  88             fh->fh_Flags &= ~FHF_APPEND;
  89
  90         newmode &= ~FMF_APPEND;
  91
  92         newflags = newmode;
  93         mask     = 0xFFFFFFFF;
  94     }
  95
  96     /* Prepare I/O request. */
  97     InitIOFS(&iofs, FSA_FILE_MODE, DOSBase);
  98
  99     iofs.IOFS.io_Device = fh->fh_Device;
 100     iofs.IOFS.io_Unit   = fh->fh_Unit;
 101
 102     iofs.io_Union.io_FILE_MODE.io_FileMode = newflags;
 103     iofs.io_Union.io_FILE_MODE.io_Mask     = mask;
 104
 105     /* Send the request. */
 106     DosDoIO(&iofs.IOFS);
 107
 108     /* Set error code and return */
 109     if (iofs.io_DosError != 0)
 110     {
 111         SetIoErr(iofs.io_DosError);
 112         return DOSFALSE;
 113     }
 114
 115     return DOSTRUE;
 116
 117     AROS_LIBFUNC_EXIT
 118 } /* ChangeMode */