rom/dos/readlink.c

   1 /*
   2     Copyright © 1995-2010, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Read the soft-link information.
   6     Lang: English
   7 */
   8 #include "dos_intern.h"
   9 #include <dos/filesystem.h>
  10 #include <exec/lists.h>
  11 #include <proto/exec.h>
  12
  13 struct ReadLinkDeviceUnit
  14 {
  15     struct MinNode node;
  16     struct Device *device;
  17     struct Unit *unit;
  18 };
  19
  20 /*****************************************************************************
  21
  22     NAME */
  23 #include <proto/dos.h>
  24
  25         AROS_LH5(LONG, ReadLink,
  26
  27 /*  SYNOPSIS */
  28         AROS_LHA(struct MsgPort *, port, D1),
  29         AROS_LHA(BPTR            , lock, D2),
  30         AROS_LHA(CONST_STRPTR    , path, D3),
  31         AROS_LHA(STRPTR          , buffer, D4),
  32         AROS_LHA(ULONG           , size, D5),
  33
  34 /*  LOCATION */
  35         struct DosLibrary *, DOSBase, 73, Dos)
  36
  37 /*  FUNCTION
  38         Read the filename referred to by the soft-linked object contained
  39         in |path| (relative to the lock |lock|) into the buffer |buffer|.
  40         The variable |path| should contain the name of the object that
  41         caused the original OBJECT_IS_SOFT_LINK error.
  42
  43     INPUTS
  44         port            - The handler to send the request to.
  45         lock            - Object that |path| is relative to.
  46         path            - Name of the object that caused the error.
  47         buffer          - Buffer to fill with resolved filename.
  48         size            - Length of the buffer.
  49
  50     RESULT
  51         >= 0    length of resolved filename in case of success
  52         == -1   failure, see IoErr() for more information
  53         == -2   buffer size was too small to store resolved filename
  54
  55     NOTES
  56
  57     EXAMPLE
  58
  59     BUGS
  60
  61     SEE ALSO
  62         MakeLink()
  63
  64     INTERNALS
  65
  66 *****************************************************************************/
  67 {
  68     AROS_LIBFUNC_INIT
  69
  70     struct IOFileSys iofs;
  71     struct FileHandle *fh = BADDR(lock);
  72     LONG err = 0;
  73     LONG ret = -1;
  74
  75     InitIOFS(&iofs, FSA_READ_SOFTLINK, DOSBase);
  76
  77     iofs.io_Union.io_READ_SOFTLINK.io_Buffer = buffer;
  78     iofs.io_Union.io_READ_SOFTLINK.io_Size   = size;
  79
  80     if(fh)
  81     {
  82         iofs.IOFS.io_Device = fh->fh_Device;
  83         iofs.IOFS.io_Unit   = fh->fh_Unit;
  84
  85         err = DoIOFS(&iofs, NULL, path, DOSBase);
  86         if(!err)
  87            ret = iofs.io_Union.io_READ_SOFTLINK.io_Size;
  88     }
  89     else
  90     {
  91         struct DosList *dl = NULL;
  92         struct ReadLinkDeviceUnit *deviceunit;
  93         struct MinList deviceunits;
  94         struct Node *tmpNode;
  95         char found = 0;
  96         NEWLIST(&deviceunits);
  97
  98         /* Quickly get all device units with such port, store them in
  99            temporary list. */
 100         for (
 101             dl = LockDosList(LDF_DEVICES | LDF_READ);
 102             dl != NULL;
 103             dl = BADDR(dl->dol_Next)
 104         )
 105         {
 106             if(
 107                 dl->dol_Type == DLT_DEVICE && (
 108                 (struct MsgPort *)dl->dol_Ext.dol_AROS.dol_Device == port)
 109             )
 110             {
 111                 if((deviceunit = AllocMem(
 112                     sizeof(struct ReadLinkDeviceUnit),
 113                     MEMF_ANY | MEMF_CLEAR
 114                 )))
 115                 {
 116                     deviceunit->device = dl->dol_Ext.dol_AROS.dol_Device;
 117                     deviceunit->unit = dl->dol_Ext.dol_AROS.dol_Unit;
 118                     AddTail(
 119                         (struct List*) &deviceunits,
 120                         (struct Node*) deviceunit
 121                     );
 122                 }
 123                 else
 124                 {
 125                     err = ERROR_NO_FREE_STORE;
 126                     break;
 127                 }
 128             }
 129         }
 130         UnLockDosList(LDF_DEVICES | LDF_READ);
 131
 132         if(!err)
 133         {
 134             /* Now try all units from the list */
 135             ForeachNode(&deviceunits, deviceunit)
 136             {
 137                 iofs.IOFS.io_Device = deviceunit->device;
 138                 iofs.IOFS.io_Unit = deviceunit->unit;
 139                 iofs.io_Union.io_READ_SOFTLINK.io_Size     = size;
 140
 141                 err = DoIOFS(&iofs, NULL, path, DOSBase);
 142                 if(!err)
 143                 {
 144                     ret = iofs.io_Union.io_READ_SOFTLINK.io_Size;
 145                     found = 1;
 146                     break;
 147                 }
 148             }
 149
 150             if(!found)
 151                 err = ERROR_OBJECT_NOT_FOUND;
 152         }
 153
 154         /* Free our temporary list */
 155         ForeachNodeSafe(&deviceunits, deviceunit, tmpNode)
 156         {
 157             Remove((struct Node*) deviceunit);
 158             FreeMem(deviceunit, sizeof(struct ReadLinkDeviceUnit));
 159         }
 160     }
 161
 162     SetIoErr(err);
 163
 164     return err == 0 ? ret : -1;
 165
 166     AROS_LIBFUNC_EXIT
 167 } /* ReadLink */