rom/dos/lock.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Locks a file or directory.
   6     Lang: English
   7 */
   8
   9 #include <proto/exec.h>
  10 #include <utility/tagitem.h>
  11 #include <dos/dosextens.h>
  12 #include <dos/filesystem.h>
  13 #include <proto/dos.h>
  14 #include <proto/utility.h>
  15 #include "dos_intern.h"
  16
  17 #define  DEBUG  0
  18 #include <aros/debug.h>
  19
  20
  21 /*****************************************************************************
  22
  23     NAME */
  24 #include <proto/dos.h>
  25
  26         AROS_LH2(BPTR, Lock,
  27
  28 /*  SYNOPSIS */
  29         AROS_LHA(CONST_STRPTR, name,       D1),
  30         AROS_LHA(LONG,         accessMode, D2),
  31
  32 /*  LOCATION */
  33         struct DosLibrary *, DOSBase, 14, Dos)
  34
  35 /*  FUNCTION
  36         Gets a lock on a file or directory. There may be more than one
  37         shared lock on a file but only one if it is an exclusive one.
  38         Locked files or directories may not be deleted.
  39
  40     INPUTS
  41         name       - NUL terminated name of the file or directory.
  42         accessMode - One of SHARED_LOCK
  43                             EXCLUSIVE_LOCK
  44
  45     RESULT
  46         Handle to the file or directory or 0 if the object couldn't be locked.
  47         IoErr() gives additional information in that case.
  48
  49     NOTES
  50         The lock structure returned by this function is different
  51         from that of AmigaOS (in fact it is identical to a filehandle).
  52         Do not try to read any internal fields.
  53
  54 *****************************************************************************/
  55
  56 {
  57     AROS_LIBFUNC_INIT
  58
  59     struct DevProc *dvp;
  60     LONG error;
  61
  62     ASSERT_VALID_PTR(name);
  63
  64     /* Sanity check */
  65     if (name == NULL)
  66         return NULL;
  67
  68     /* Get pointer to process structure */
  69         struct Process *
  70     me = (struct Process *)FindTask(NULL);
  71
  72     /* Create filehandle */
  73         struct FileHandle *
  74     ret = (struct FileHandle *)AllocDosObject(DOS_FILEHANDLE, NULL);
  75
  76     if (ret != NULL)
  77     {
  78         /* Get pointer to I/O request. Use stackspace for now. */
  79         struct IOFileSys iofs;
  80
  81         /* Prepare I/O request. */
  82         InitIOFS(&iofs, FSA_OPEN, DOSBase);
  83
  84         switch (accessMode)
  85         {
  86                 case EXCLUSIVE_LOCK:
  87                     iofs.io_Union.io_OPEN.io_FileMode = FMF_LOCK | FMF_READ;
  88                     break;
  89
  90                 case SHARED_LOCK:
  91                     iofs.io_Union.io_OPEN.io_FileMode = FMF_READ;
  92                     break;
  93
  94                 default:
  95                     D(bug("[Lock] incompatible mode %d\n", accessMode));
  96                     FreeDosObject(DOS_FILEHANDLE, ret);
  97                     SetIoErr(ERROR_ACTION_NOT_KNOWN);
  98                     return NULL;
  99         }
 100
 101         /* catch the zero-length special case. we can't (currently) call
 102          * GetDeviceProc(), as it will call NameFromLock(), which will
 103          * DupLock(), which will end up here */
 104         if (*name == '\0') {
 105             BPTR cur;
 106             struct FileHandle *fh;
 107
 108             cur = me->pr_CurrentDir;
 109             if (!cur)
 110                 cur = DOSBase->dl_SYSLock;
 111
 112             if (cur) {
 113                 fh = BADDR(cur);
 114
 115                 iofs.io_Union.io_OPEN.io_Filename = "";
 116
 117                 iofs.IOFS.io_Device = fh->fh_Device;
 118                 iofs.IOFS.io_Unit = fh->fh_Unit;
 119
 120                 DosDoIO(&iofs.IOFS);
 121
 122                 error = me->pr_Result2 = iofs.io_DosError;
 123             } else {
 124                 error = ERROR_OBJECT_NOT_FOUND;
 125                 SetIoErr(error);
 126             }
 127         }
 128
 129         else {
 130             iofs.io_Union.io_OPEN.io_Filename = StripVolume(name);
 131
 132             dvp = NULL;
 133
 134             do {
 135                 if ((dvp = GetDeviceProc(name, dvp)) == NULL) {
 136                     error = IoErr();
 137                     break;
 138                 }
 139
 140                 error = DoIOFS(&iofs, dvp, NULL, DOSBase);
 141             } while (error == ERROR_OBJECT_NOT_FOUND);
 142
 143             if (error == ERROR_NO_MORE_ENTRIES)
 144                 error = me->pr_Result2 = ERROR_OBJECT_NOT_FOUND;
 145
 146             FreeDeviceProc(dvp);
 147         }
 148
 149         if (!error)
 150         {
 151             ret->fh_Device = iofs.IOFS.io_Device;
 152             ret->fh_Unit   = iofs.IOFS.io_Unit;
 153
 154             return MKBADDR(ret);
 155         }
 156         else
 157         {
 158             FreeDosObject(DOS_FILEHANDLE, ret);
 159         }
 160     }
 161     else
 162     {
 163         SetIoErr(ERROR_NO_FREE_STORE);
 164     }
 165
 166     return NULL;
 167
 168     AROS_LIBFUNC_EXIT
 169 } /* Lock */