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/* Editor Settings: expandtabs and use 4 spaces for indentation
* ex: set softtabstop=4 tabstop=8 expandtab shiftwidth=4: *
* -*- mode: c, c-basic-offset: 4 -*- */
/*
* Copyright Likewise Software
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details. You should have received a copy of the GNU General
* Public License along with this program. If not, see
* <http://www.gnu.org/licenses/>.
*
* LIKEWISE SOFTWARE MAKES THIS SOFTWARE AVAILABLE UNDER OTHER LICENSING
* TERMS AS WELL. IF YOU HAVE ENTERED INTO A SEPARATE LICENSE AGREEMENT
* WITH LIKEWISE SOFTWARE, THEN YOU MAY ELECT TO USE THE SOFTWARE UNDER THE
* TERMS OF THAT SOFTWARE LICENSE AGREEMENT INSTEAD OF THE TERMS OF THE GNU
* GENERAL PUBLIC LICENSE, NOTWITHSTANDING THE ABOVE NOTICE. IF YOU
* HAVE QUESTIONS, OR WISH TO REQUEST A COPY OF THE ALTERNATE LICENSING
* TERMS OFFERED BY LIKEWISE SOFTWARE, PLEASE CONTACT LIKEWISE SOFTWARE AT
* license@likewisesoftware.com
*/
/*
* Copyright (C) Likewise Software. All rights reserved.
*
* Module Name:
*
* sharemode.c
*
* Abstract:
*
* Likewise Posix File System Driver (PVFS)
*
* Support for Windows File Share Modes
*
* Authors: Gerald Carter <gcarter@likewise.com>
*/
#include "pvfs.h"
/* Forward declarations */
/* Code */
/***********************************************************
**********************************************************/
NTSTATUS
PvfsCheckShareMode(
IN PSTR pszFilename,
IN FILE_SHARE_FLAGS SharedAccess,
IN ACCESS_MASK DesiredAccess,
OUT PPVFS_FCB *ppFcb
)
{
NTSTATUS ntError = STATUS_SUCCESS;
PPVFS_FCB pFcb = NULL;
ntError = PvfsFindFCB(&pFcb, pszFilename);
if (ntError == STATUS_SUCCESS) {
ntError = PvfsEnforceShareMode(
pFcb,
SharedAccess,
DesiredAccess);
/* If we have success, then we are good. If we have a sharing
violation, give the caller a chance to break the oplock and
we'll try again when the create is resumed. */
if (ntError == STATUS_SUCCESS ||
ntError == STATUS_SHARING_VIOLATION)
{
*ppFcb = PvfsReferenceFCB(pFcb);
}
goto cleanup;
}
if (ntError != STATUS_OBJECT_NAME_NOT_FOUND)
{
BAIL_ON_NT_STATUS(ntError);
}
/* If not found, then add one */
ntError = PvfsCreateFCB(
&pFcb,
pszFilename,
SharedAccess,
DesiredAccess);
BAIL_ON_NT_STATUS(ntError);
*ppFcb = PvfsReferenceFCB(pFcb);
ntError = STATUS_SUCCESS;
cleanup:
if (pFcb) {
PvfsReleaseFCB(&pFcb);
}
return ntError;
error:
goto cleanup;
}
/***********************************************************
**********************************************************/
static NTSTATUS
_PvfsEnforceShareMode(
IN PPVFS_FCB pFcb,
IN FILE_SHARE_FLAGS ShareAccess,
IN ACCESS_MASK DesiredAccess
);
NTSTATUS
PvfsEnforceShareMode(
IN PPVFS_FCB pFcb,
IN FILE_SHARE_FLAGS ShareAccess,
IN ACCESS_MASK DesiredAccess
)
{
NTSTATUS ntError = STATUS_UNSUCCESSFUL;
int i = 0;
ULONG RetryMax = 3;
struct timespec SleepTime = {0};
struct timespec RemainingTime = {0};
for (i=0; i<RetryMax && (ntError != STATUS_SUCCESS); i++)
{
ntError = _PvfsEnforceShareMode(pFcb, ShareAccess, DesiredAccess);
if ((ntError == STATUS_SHARING_VIOLATION) && (i<(RetryMax-1)))
{
NTSTATUS ntErrorSleep = STATUS_SUCCESS;
/* 2 milliseconds */
RemainingTime.tv_sec = 0;
RemainingTime.tv_nsec = 2 * 1000000;
do {
SleepTime.tv_sec = RemainingTime.tv_sec;
SleepTime.tv_nsec = RemainingTime.tv_nsec;
ntErrorSleep = PvfsSysNanoSleep(&SleepTime, &RemainingTime);
} while (ntErrorSleep == STATUS_MORE_PROCESSING_REQUIRED);
continue;
}
BAIL_ON_NT_STATUS(ntError);
}
cleanup:
return ntError;
error:
goto cleanup;
}
/***********************************************************
**********************************************************/
struct _SHARE_MODE_ACCESS_COMPATIBILITY
{
FILE_SHARE_FLAGS ShareFlag;
ACCESS_MASK Access;
} ShareModeTable[] = {
{ FILE_SHARE_READ, (FILE_READ_DATA|FILE_EXECUTE) },
{ FILE_SHARE_WRITE, (FILE_WRITE_DATA|FILE_APPEND_DATA) },
{ FILE_SHARE_DELETE, (DELETE) }
};
NTSTATUS
_PvfsEnforceShareMode(
IN PPVFS_FCB pFcb,
IN FILE_SHARE_FLAGS ShareAccess,
IN ACCESS_MASK DesiredAccess
)
{
NTSTATUS ntError = STATUS_SUCCESS;
PLW_LIST_LINKS pCursor = NULL;
PPVFS_CCB pCcb = NULL;
BOOLEAN bLocked = FALSE;
ACCESS_MASK AllRights = (FILE_READ_DATA|
FILE_WRITE_DATA|
FILE_APPEND_DATA|
FILE_EXECUTE|
DELETE);
DWORD TableSize = sizeof(ShareModeTable) /
sizeof(struct _SHARE_MODE_ACCESS_COMPATIBILITY);
int i = 0;
RtlMapGenericMask(&DesiredAccess, &gPvfsFileGenericMapping);
LWIO_LOCK_RWMUTEX_SHARED(bLocked, &pFcb->rwCcbLock);
while ((pCursor = PvfsListTraverse(pFcb->pCcbList, pCursor)) != NULL)
{
pCcb = LW_STRUCT_FROM_FIELD(
pCursor,
PVFS_CCB,
FcbList);
/* Ignore handles that are in the midst of being closed */
if (pCcb->bCloseInProgress)
{
continue;
}
/* Fast Path - If we are not asking for read/write/execute/delete
access, then we cannot conflict */
if (((DesiredAccess & AllRights) == 0) ||
((pCcb->AccessGranted & AllRights) == 0))
{
continue;
}
for (i=0; i<TableSize; i++)
{
/* Check for a conflict between the request access and
an existing share mode */
if ((DesiredAccess & ShareModeTable[i].Access) &&
(!(pCcb->ShareFlags & ShareModeTable[i].ShareFlag)))
{
ntError = STATUS_SHARING_VIOLATION;
BAIL_ON_NT_STATUS(ntError);
}
/* Check for a conflict between the request share mode
and an existing granted access mask */
if ((pCcb->AccessGranted & ShareModeTable[i].Access) &&
(!(ShareAccess & ShareModeTable[i].ShareFlag)))
{
ntError = STATUS_SHARING_VIOLATION;
BAIL_ON_NT_STATUS(ntError);
}
}
pCcb = NULL;
}
/* Cone - No conflicts*/
ntError = STATUS_SUCCESS;
cleanup:
LWIO_UNLOCK_RWMUTEX(bLocked, &pFcb->rwCcbLock);
return ntError;
error:
goto cleanup;
}
/*
local variables:
mode: c
c-basic-offset: 4
indent-tabs-mode: nil
tab-width: 4
end:
*/
|