rom/dos/openfromlock.c

   1 /*
   2     Copyright © 1995-2008, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Open a file from a 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 #define DEBUG 0
  14 #include <aros/debug.h>
  15
  16 #ifndef SFS_SPECIFIC_MESSAGE
  17 #define SFS_SPECIFIC_MESSAGE 0xff00
  18 #endif
  19
  20 static BPTR SFSOpenFromLock(BPTR lock, struct DosLibrary *DOSBase);
  21
  22 /*****************************************************************************
  23
  24     NAME */
  25 #include <proto/dos.h>
  26
  27         AROS_LH1(BPTR, OpenFromLock,
  28
  29 /*  SYNOPSIS */
  30         AROS_LHA(BPTR, lock, D1),
  31
  32 /*  LOCATION */
  33         struct DosLibrary *, DOSBase, 63, Dos)
  34
  35 /*  FUNCTION
  36         Convert a lock into a filehandle. If all went well the lock
  37         will be gone. In case of an error it must still be freed.
  38
  39     INPUTS
  40         lock - Lock to convert.
  41
  42     RESULT
  43         New filehandle or 0 in case of an error. IoErr() will give
  44         additional information in that case.
  45
  46     NOTES
  47
  48     EXAMPLE
  49
  50     BUGS
  51
  52     SEE ALSO
  53
  54     INTERNALS
  55         Since locks and filehandles in AROS are identical this function
  56         is just the (useless) identity operator and thus can never fail.
  57         It's there for compatibility with Amiga OS.
  58
  59         As of 04/17/08:
  60         - the above note is not true anymore
  61         - the AROS packet implementation and the various DOS packets conversion
  62           layers can't handle packet type ACTION_FH_FROM_LOCK which does not
  63           exist in AROS as a consequence of the above note
  64         - we can continue to hack this way until death
  65         - the current OpenFromLock implementation is hacked to handle SFS
  66         - by the way, C:Touch does not work on SFS (AROS packets handling bug)
  67
  68 *****************************************************************************/
  69 {
  70     AROS_LIBFUNC_INIT
  71
  72     BPTR file = NULL, test_lock, old_dir;
  73     ULONG mode;
  74
  75     if (lock == NULL)
  76     {
  77         SetIoErr(ERROR_INVALID_LOCK);
  78         return NULL;
  79     }
  80
  81     /* Try SFS hack first */
  82     file = SFSOpenFromLock(lock, DOSBase);
  83
  84     /* If SFS hack failed, try more general method that should work for both
  85      * device-based and packet-based handlers */
  86     if (file == NULL)
  87     {
  88         /* Get lock's mode */
  89         test_lock = DupLock(lock);
  90         if (test_lock != (BPTR)NULL)
  91         {
  92             mode = SHARED_LOCK;
  93             UnLock(test_lock);
  94         }
  95         else
  96             mode = EXCLUSIVE_LOCK;
  97
  98         /* If necessary, switch to a SHARED_LOCK temporarily so we can open
  99            the file */
 100         if (mode == EXCLUSIVE_LOCK)
 101             ChangeMode(CHANGE_LOCK, lock, SHARED_LOCK);
 102
 103         /* Open file and dispose of no longer needed lock */
 104         old_dir = CurrentDir(lock);
 105         file = Open("", MODE_OLDFILE);
 106         CurrentDir(old_dir);
 107         if (file != (BPTR)NULL)
 108             UnLock(lock);
 109
 110         /* Restore old mode */
 111         if (mode == EXCLUSIVE_LOCK)
 112         {
 113             if (file != (BPTR)NULL)
 114                 ChangeMode(CHANGE_FH, file, mode);
 115             else
 116                 ChangeMode(CHANGE_LOCK, lock, mode);
 117         }
 118     }
 119
 120     return file;
 121
 122     AROS_LIBFUNC_EXIT
 123 } /* OpenFromLock */
 124
 125 static BPTR SFSOpenFromLock(BPTR lock, struct DosLibrary *DOSBase)
 126 {
 127     struct MsgPort *mp;
 128     struct IOFileSys iofs;
 129     struct DosPacket pkt = {0};
 130     struct FileHandle *fh;
 131     BPTR file = NULL;
 132
 133     struct ASFSHandle
 134     {
 135         void *handle;
 136         ULONG flags;
 137         struct ASFSDeviceInfo *device;
 138     };
 139
 140     struct ASFSHandle *asfshandle;
 141
 142     fh = (struct FileHandle *)BADDR(lock);
 143
 144     if (fh->fh_Unit)
 145     {
 146         asfshandle = (struct ASFSHandle *)fh->fh_Unit;
 147
 148         mp = CreateMsgPort();
 149         if (!mp)
 150         {
 151             SetIoErr(ERROR_NO_FREE_STORE);
 152             return NULL;
 153         }
 154
 155         InitIOFS(&iofs, SFS_SPECIFIC_MESSAGE, DOSBase);
 156
 157         iofs.IOFS.io_Device  = fh->fh_Device;
 158         iofs.IOFS.io_Unit    = fh->fh_Unit;
 159
 160         fh = (struct FileHandle *)AllocDosObject(DOS_FILEHANDLE, NULL);
 161         if (!fh)
 162         {
 163             DeleteMsgPort(mp);
 164             SetIoErr(ERROR_NO_FREE_STORE);
 165             return NULL;
 166         }
 167
 168         fh->fh_Pos = fh->fh_End = (UBYTE *)-1;
 169
 170         pkt.dp_Type = ACTION_FH_FROM_LOCK;
 171         pkt.dp_Arg1 = (SIPTR)MKBADDR(fh);
 172         pkt.dp_Arg2 = (SIPTR)asfshandle->handle;
 173
 174         iofs.io_PacketEmulation = &pkt;
 175
 176         DosDoIO((struct IORequest *)&iofs);
 177
 178         D(bug("OpenFromLock dp_Res1=%d IoErr=%d\n",
 179               pkt.dp_Res1, iofs.io_DosError));
 180         switch (iofs.io_DosError)
 181         {
 182         case ERROR_ACTION_NOT_KNOWN:
 183         case ERROR_NOT_IMPLEMENTED:
 184             FreeDosObject(DOS_FILEHANDLE, fh);
 185             file = NULL;
 186             break;
 187         default:
 188             if (pkt.dp_Res1)
 189             {
 190                 fh->fh_Device = iofs.IOFS.io_Device;
 191                 fh->fh_Unit   = iofs.IOFS.io_Unit;
 192                 file = MKBADDR(fh);
 193             }
 194             else
 195             {
 196                 SetIoErr(iofs.io_DosError);
 197                 FreeDosObject(DOS_FILEHANDLE, fh);
 198                 file = NULL;
 199             }
 200         }
 201
 202         DeleteMsgPort(mp);
 203     }
 204
 205     return file;
 206 }
 207