update Changlog for v1.9

Credential: Default do not save password

.github/workflows/avm.yml

@@ -13,3 +13,4 @@ jobs:
         files: |
             https://github.com/billziss-gh/winfsp/releases/download/v1.6/winfsp-1.6.20027.msi
             https://github.com/billziss-gh/winfsp/releases/download/v1.7B1/winfsp-1.7.20038.msi
+            https://github.com/billziss-gh/winfsp/releases/download/v1.8/winfsp-1.8.20304.msi

Changelog.asciidoc

@@ -1,6 +1,54 @@
 = Changelog
 
 
+v1.9 (2021)::
+
+Changes since v1.8:
+
+* [NEW] WinFsp now supports file change notifications and cache invalidations. This functionality is offered via the following new API's:
+** Native API: `FspFileSystemNotify`
+** FUSE API: `fuse_notify`
+** .NET API: `FileSystemHost.Notify`
+
+* [NEW] A native file system (notifyfs) and a .NET file system (notifyfs-dotnet) have been added to showcase the new file change notification API.
+
+* [NEW] A new WinFsp-FUSE option `FileSecurity` has been added that allows the complete specification of file security descriptors using SDDL. (See GitHub issue https://github.com/rclone/rclone/issues/4717#issuecomment-767723287.)
+
+* [FIX] The FSD now correctly handles a rare situation where receiving too many CLOSE calls from the OS (e.g. when caching thousands of files) could result in a bogus "insufficient resources" error. (See commit 0af0bfbe7c45e353d693a2a45965d99fa81f2163.)
+
+* [FIX] WinFsp-FUSE correctly maps SID's from trusted domains to POSIX UID's in a multi-domain environment (using the "trustPosixOffset" attribute). Previously WinFsp-FUSE only handled SID's from the primary domain correctly.
+
+* [FIX] WinFsp-FUSE options such as `volname`, `VolumePrefix`, `FileSystemName`, `ExactFileSystemName` are now truncated when too long. (See GitHub issue #311.)
+
+* [FIX] The WinFsp driver is now started in a thread-safe manner if it is not already running. (See GitHub issue billziss-gh/cgofuse#51.)
+
+* [FIX] Credentials entered in the Credentials dialog (when mapping network drives) are no longer saved by default. (See GitHub PR #342. Thanks @gaotxg.)
+
+
+v1.9B2 (2021 Beta2)::
+
+Changes since v1.8:
+
+* [NEW] WinFsp now supports file change notifications and cache invalidations. This functionality is offered via the following new API's:
+** Native API: `FspFileSystemNotify`
+** FUSE API: `fuse_notify`
+** .NET API: `FileSystemHost.Notify`
+
+* [NEW] A native file system (notifyfs) and a .NET file system (notifyfs-dotnet) have been added to showcase the new file change notification API.
+
+* [NEW] A new WinFsp-FUSE option `FileSecurity` has been added that allows the complete specification of file security descriptors using SDDL. (See GitHub issue https://github.com/rclone/rclone/issues/4717#issuecomment-767723287.)
+
+* [FIX] The FSD now correctly handles a rare situation where receiving too many CLOSE calls from the OS (e.g. when caching thousands of files) could result in a bogus "insufficient resources" error. (See commit 0af0bfbe7c45e353d693a2a45965d99fa81f2163.)
+
+* [FIX] WinFsp-FUSE correctly maps SID's from trusted domains to POSIX UID's in a multi-domain environment (using the "trustPosixOffset" attribute). Previously WinFsp-FUSE only handled SID's from the primary domain correctly.
+
+* [FIX] WinFsp-FUSE options such as `volname`, `VolumePrefix`, `FileSystemName`, `ExactFileSystemName` are now truncated when too long. (See GitHub issue #311.)
+
+* [FIX] The WinFsp driver is now started in a thread-safe manner if it is not already running. (See GitHub issue billziss-gh/cgofuse#51.)
+
+* [FIX] Credentials entered in the Credentials dialog (when mapping network drives) are no longer saved by default. (See GitHub PR #342. Thanks @gaotxg.)
+
+
 v1.9B1 (2021 Beta1)::
 
 Changes since v1.8:

Contributors.asciidoc

@@ -54,6 +54,7 @@ This CONTRIBUTOR AGREEMENT applies to any contribution that you make to the WinF
 CONTRIBUTOR LIST
 ----------------
 |===
+|Alberto Alonso                                                 |alberto at alonso.xyz
 |Ben Rubson                                                     |ben.rubson at gmail.com
 |Bill Zissimopoulos                                             |billziss at navimatics.com
 |Brett Dutro                                                    |brett.dutro at gmail.com
@@ -68,4 +69,5 @@ CONTRIBUTOR LIST
 |Sam Kelly (DuroSoft Technologies LLC, https://durosoft.com)    |sam at durosoft.com
 |Santiago Ganis                                                 |sganis at gmail.com
 |Tobias Urlaub                                                  |saibotu at outlook.de
+|Victor Gao                                                     |victgm at outlook.com
 |===

build/VStudio/installer/Product.wxs

@@ -538,6 +538,31 @@
                     <File Name="passthrough-dotnet.csproj" KeyPath="yes" />
                 </Component>
             </Directory>
+            <Directory Id="SMPDIR.notifyfs" Name="notifyfs">
+                <Component Id="C.notifyfs.c">
+                    <File Name="notifyfs.c" KeyPath="yes" />
+                </Component>
+                <Component Id="C.notifyfs.sln">
+                    <File Name="notifyfs.sln" KeyPath="yes" />
+                </Component>
+                <Component Id="C.notifyfs.vcxproj">
+                    <File Name="notifyfs.vcxproj" KeyPath="yes" />
+                </Component>
+                <Component Id="C.notifyfs.vcxproj.filters">
+                    <File Name="notifyfs.vcxproj.filters" KeyPath="yes" />
+                </Component>
+            </Directory>
+            <Directory Id="SMPDIR.notifyfs_dotnet" Name="notifyfs-dotnet">
+                <Component Id="C.notifyfs_dotnet.Program.cs">
+                    <File Id="FILE.notifyfs_dotnet.Program.cs" Name="Program.cs" KeyPath="yes" />
+                </Component>
+                <Component Id="C.notifyfs_dotnet.sln">
+                    <File Name="notifyfs-dotnet.sln" KeyPath="yes" />
+                </Component>
+                <Component Id="C.notifyfs_dotnet.csproj">
+                    <File Name="notifyfs-dotnet.csproj" KeyPath="yes" />
+                </Component>
+            </Directory>
         </DirectoryRef>
         <DirectoryRef Id="SYMDIR">
             <Component Id="C.winfsp_x64.sys.pdb">
@@ -674,6 +699,10 @@
             <ComponentRef Id="C.passthrough_fuse3.vcxproj.filters" />
             <ComponentRef Id="C.passthrough_fuse3.Makefile" />
             <ComponentRef Id="C.passthrough_fuse3.README.md" />
+            <ComponentRef Id="C.notifyfs.c" />
+            <ComponentRef Id="C.notifyfs.sln" />
+            <ComponentRef Id="C.notifyfs.vcxproj" />
+            <ComponentRef Id="C.notifyfs.vcxproj.filters" />
         </ComponentGroup>
         <ComponentGroup Id="C.WinFsp.sym">
             <ComponentRef Id="C.winfsp_x64.sys.pdb" />
@@ -703,6 +732,9 @@
             <ComponentRef Id="C.passthrough_dotnet.Program.cs" />
             <ComponentRef Id="C.passthrough_dotnet.sln" />
             <ComponentRef Id="C.passthrough_dotnet.csproj" />
+            <ComponentRef Id="C.notifyfs_dotnet.Program.cs" />
+            <ComponentRef Id="C.notifyfs_dotnet.sln" />
+            <ComponentRef Id="C.notifyfs_dotnet.csproj" />
         </ComponentGroup>
 
         <Feature

build/VStudio/version.properties

@@ -18,8 +18,8 @@
 
         <MyCanonicalVersion>1.9</MyCanonicalVersion>
 
-        <MyProductVersion>2021 Beta1</MyProductVersion>
+        <MyProductVersion>2021</MyProductVersion>
-        <MyProductStage>Beta</MyProductStage>
+        <MyProductStage>Gold</MyProductStage>
 
         <MyVersion>$(MyCanonicalVersion).$(MyBuildNumber)</MyVersion>
         <MyVersionWithCommas>$(MyVersion.Replace('.',',')),0</MyVersionWithCommas>

build/VStudio/winfsp_sys.vcxproj

@@ -187,6 +187,7 @@
     <ClCompile Include="..\..\src\sys\shutdown.c" />
     <ClCompile Include="..\..\src\sys\silo.c" />
     <ClCompile Include="..\..\src\sys\statistics.c" />
+    <ClCompile Include="..\..\src\sys\trace.c" />
     <ClCompile Include="..\..\src\sys\util.c" />
     <ClCompile Include="..\..\src\sys\volinfo.c" />
     <ClCompile Include="..\..\src\sys\volume.c" />

build/VStudio/winfsp_sys.vcxproj.filters

@@ -125,6 +125,9 @@
     <ClCompile Include="..\..\src\sys\silo.c">
       <Filter>Source</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\sys\trace.c">
+      <Filter>Source</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\src\sys\driver.h">

inc/winfsp/winfsp.h

@@ -1826,6 +1826,10 @@ FSP_API VOID FspDeleteSid(PSID Sid, NTSTATUS (*CreateFunc)());
 FSP_API NTSTATUS FspPosixMapPermissionsToSecurityDescriptor(
     UINT32 Uid, UINT32 Gid, UINT32 Mode,
     PSECURITY_DESCRIPTOR *PSecurityDescriptor);
+FSP_API NTSTATUS FspPosixMergePermissionsToSecurityDescriptor(
+    UINT32 Uid, UINT32 Gid, UINT32 Mode,
+    PSECURITY_DESCRIPTOR ExistingSecurityDescriptor,
+    PSECURITY_DESCRIPTOR *PSecurityDescriptor);
 FSP_API NTSTATUS FspPosixMapSecurityDescriptorToPermissions(
     PSECURITY_DESCRIPTOR SecurityDescriptor,
     PUINT32 PUid, PUINT32 PGid, PUINT32 PMode);

src/dll/fsctl.c

@@ -254,6 +254,7 @@ FSP_API NTSTATUS FspFsctlPreflight(PWSTR DevicePath)
 
 static NTSTATUS FspFsctlStartService(VOID)
 {
+    static SRWLOCK Lock = SRWLOCK_INIT;
     PWSTR DriverName = L"" FSP_FSCTL_DRIVER_NAME;
     SC_HANDLE ScmHandle = 0;
     SC_HANDLE SvcHandle = 0;
@@ -261,6 +262,8 @@ static NTSTATUS FspFsctlStartService(VOID)
     DWORD LastError;
     NTSTATUS Result;
 
+    AcquireSRWLockExclusive(&Lock);
+
     /* Determine if we are running inside container.
      *
      * See https://github.com/microsoft/perfview/blob/V1.9.65/src/TraceEvent/TraceEventSession.cs#L525
@@ -331,6 +334,8 @@ exit:
     if (0 != ScmHandle)
         CloseServiceHandle(ScmHandle);
 
+    ReleaseSRWLockExclusive(&Lock);
+
     return Result;
 }
 

src/dll/fuse/fuse.c

@@ -20,6 +20,7 @@
  */
 
 #include <dll/fuse/library.h>
+#include <sddl.h>
 
 struct fuse_chan
 {
@@ -105,6 +106,8 @@ static struct fuse_opt fsp_fuse_core_opts[] =
     FUSE_OPT_KEY("ExactFileSystemName=", 'E'),
     FUSE_OPT_KEY("--ExactFileSystemName=", 'E'),
 
+    FUSE_OPT_KEY("FileSecurity=", 's'),
+    FUSE_OPT_KEY("--FileSecurity=", 's'),
     FSP_FUSE_CORE_OPT("UserName=", set_uid, 1),
     FUSE_OPT_KEY("UserName=", 'u'),
     FSP_FUSE_CORE_OPT("--UserName=", set_uid, 1),
@@ -266,6 +269,29 @@ FSP_FUSE_API int fsp_fuse_is_lib_option(struct fsp_fuse_env *env,
     return fsp_fuse_opt_match(env, fsp_fuse_core_opts, opt);
 }
 
+static int fsp_fuse_sddl_to_security(const char *Sddl, PUINT8 Security, PULONG PSecuritySize)
+{
+    PSECURITY_DESCRIPTOR SecurityDescriptor;
+    ULONG SecurityDescriptorSize;
+    int res = -1;
+
+    if (ConvertStringSecurityDescriptorToSecurityDescriptorA(
+        Sddl, SDDL_REVISION_1, &SecurityDescriptor, &SecurityDescriptorSize))
+    {
+        if (*PSecuritySize >= SecurityDescriptorSize)
+        {
+            memcpy(Security, SecurityDescriptor, SecurityDescriptorSize);
+            *PSecuritySize = SecurityDescriptorSize;
+
+            res = 0;
+        }
+
+        LocalFree(SecurityDescriptor);
+    }
+
+    return res;
+}
+
 static int fsp_fuse_username_to_uid(const char *username, int *puid)
 {
     union
@@ -303,6 +329,63 @@ static int fsp_fuse_username_to_uid(const char *username, int *puid)
     return 0;
 }
 
+static int fsp_fuse_utf8towcs_trunc(
+    const char *Str, int StrLen,
+    PWSTR Wcs, int WcsLen)
+{
+    if (0 == StrLen)
+        return 0;
+
+    int Size = MultiByteToWideChar(CP_UTF8, 0, Str, StrLen, Wcs, WcsLen);
+    if (0 != Size)
+        return Size;
+
+    if (0 == WcsLen)
+        return 0;
+
+    PWSTR Buf = 0;
+
+    Size = MultiByteToWideChar(CP_UTF8, 0, Str, StrLen, 0, 0);
+    if (0 == Size)
+        goto exit;
+
+    Buf = MemAlloc(Size * sizeof(WCHAR));
+    if (0 == Buf)
+    {
+        SetLastError(ERROR_NO_SYSTEM_RESOURCES);
+        Size = 0;
+        goto exit;
+    }
+
+    Size = MultiByteToWideChar(CP_UTF8, 0, Str, StrLen, Buf, Size);
+    if (0 == Size)
+        goto exit;
+
+    if (-1 == StrLen)
+    {
+        if (Size >= WcsLen)
+        {
+            Size = WcsLen - 1;
+            memcpy(Wcs, Buf, Size * sizeof(WCHAR));
+            Wcs[Size] = L'\0';
+            Size++;
+        }
+        else
+            memcpy(Wcs, Buf, Size * sizeof(WCHAR));
+    }
+    else
+    {
+        if (Size >= WcsLen)
+            Size = WcsLen;
+        memcpy(Wcs, Buf, Size * sizeof(WCHAR));
+    }
+
+exit:
+    MemFree(Buf);
+
+    return Size;
+}
+
 static int fsp_fuse_core_opt_proc(void *opt_data0, const char *arg, int key,
     struct fuse_args *outargs)
 {
@@ -317,6 +400,7 @@ static int fsp_fuse_core_opt_proc(void *opt_data0, const char *arg, int key,
         FspServiceLog(EVENTLOG_ERROR_TYPE, L""
             FSP_FUSE_LIBRARY_NAME " options:\n"
             "    -o umask=MASK              set file permissions (octal)\n"
+            "    -o FileSecurity=SDDL       set file DACL (SDDL format)\n"
             "    -o create_umask=MASK       set newly created file permissions (octal)\n"
             "        -o create_file_umask=MASK      for files only\n"
             "        -o create_dir_umask=MASK       for directories only\n"
@@ -367,7 +451,7 @@ static int fsp_fuse_core_opt_proc(void *opt_data0, const char *arg, int key,
             arg += sizeof "VolumePrefix=" - 1;
         else if ('V' == arg[2])
             arg += sizeof "--VolumePrefix=" - 1;
-        if (0 == MultiByteToWideChar(CP_UTF8, 0, arg, -1,
+        if (0 == fsp_fuse_utf8towcs_trunc(arg, -1,
             opt_data->VolumeParams.Prefix, sizeof opt_data->VolumeParams.Prefix / sizeof(WCHAR)))
             return -1;
         opt_data->VolumeParams.Prefix
@@ -383,7 +467,7 @@ static int fsp_fuse_core_opt_proc(void *opt_data0, const char *arg, int key,
             arg += sizeof "FileSystemName=" - 1;
         else if ('F' == arg[2])
             arg += sizeof "--FileSystemName=" - 1;
-        if (0 == MultiByteToWideChar(CP_UTF8, 0, arg, -1,
+        if (0 == fsp_fuse_utf8towcs_trunc(arg, -1,
             opt_data->VolumeParams.FileSystemName + 5,
             sizeof opt_data->VolumeParams.FileSystemName / sizeof(WCHAR) - 5))
             return -1;
@@ -396,13 +480,25 @@ static int fsp_fuse_core_opt_proc(void *opt_data0, const char *arg, int key,
             arg += sizeof "ExactFileSystemName=" - 1;
         else if ('E' == arg[2])
             arg += sizeof "--ExactFileSystemName=" - 1;
-        if (0 == MultiByteToWideChar(CP_UTF8, 0, arg, -1,
+        if (0 == fsp_fuse_utf8towcs_trunc(arg, -1,
             opt_data->VolumeParams.FileSystemName,
             sizeof opt_data->VolumeParams.FileSystemName / sizeof(WCHAR)))
             return -1;
         opt_data->VolumeParams.FileSystemName
             [sizeof opt_data->VolumeParams.FileSystemName / sizeof(WCHAR) - 1] = L'\0';
         return 0;
+    case 's':
+        if ('F' == arg[0])
+            arg += sizeof "FileSecurity=" - 1;
+        else if ('F' == arg[2])
+            arg += sizeof "--FileSecurity=" - 1;
+        opt_data->FileSecuritySize = sizeof opt_data->FileSecurityBuf;
+        if (-1 == fsp_fuse_sddl_to_security(arg, opt_data->FileSecurityBuf, &opt_data->FileSecuritySize))
+        {
+            opt_data->FileSecuritySize = (ULONG)-1;
+            return -1;
+        }
+        return 0;
     case 'u':
         if ('U' == arg[0])
             arg += sizeof "UserName=" - 1;
@@ -428,7 +524,7 @@ static int fsp_fuse_core_opt_proc(void *opt_data0, const char *arg, int key,
     case 'v':
         arg += sizeof "volname=" - 1;
         opt_data->VolumeLabelLength = (UINT16)(sizeof(WCHAR) *
-            MultiByteToWideChar(CP_UTF8, 0, arg, lstrlenA(arg),
+            fsp_fuse_utf8towcs_trunc(arg, lstrlenA(arg),
             opt_data->VolumeLabel, sizeof opt_data->VolumeLabel / sizeof(WCHAR)));
         if (0 == opt_data->VolumeLabelLength)
             return -1;
@@ -470,7 +566,12 @@ FSP_FUSE_API struct fuse *fsp_fuse_new(struct fsp_fuse_env *env,
 
     if (-1 == fsp_fuse_core_opt_parse(env, args, &opt_data, /*help=*/1))
     {
-        if (-1 == opt_data.username_to_uid_result)
+        if ((ULONG)-1 == opt_data.FileSecuritySize)
+        {
+            ErrorMessage = L": invalid file security.";
+            goto fail;
+        }
+        else if (-1 == opt_data.username_to_uid_result)
         {
             ErrorMessage = L": invalid user or group name.";
             goto fail;
@@ -539,7 +640,7 @@ FSP_FUSE_API struct fuse *fsp_fuse_new(struct fsp_fuse_env *env,
     if (L'\0' == opt_data.VolumeParams.FileSystemName[0])
         memcpy(opt_data.VolumeParams.FileSystemName, L"FUSE", 5 * sizeof(WCHAR));
 
-    f = fsp_fuse_obj_alloc(env, sizeof *f);
+    f = fsp_fuse_obj_alloc(env, sizeof *f + opt_data.FileSecuritySize);
     if (0 == f)
         goto fail;
 
@@ -559,6 +660,11 @@ FSP_FUSE_API struct fuse *fsp_fuse_new(struct fsp_fuse_env *env,
     memcpy(&f->VolumeParams, &opt_data.VolumeParams, sizeof opt_data.VolumeParams);
     f->VolumeLabelLength = opt_data.VolumeLabelLength;
     memcpy(&f->VolumeLabel, &opt_data.VolumeLabel, opt_data.VolumeLabelLength);
+    if (0 != opt_data.FileSecuritySize)
+    {
+        memcpy(f->FileSecurityBuf, opt_data.FileSecurityBuf, opt_data.FileSecuritySize);
+        f->FileSecurity = f->FileSecurityBuf;
+    }
 
     Size = (lstrlenW(ch->MountPoint) + 1) * sizeof(WCHAR);
     f->MountPoint = fsp_fuse_obj_alloc(env, Size);

src/dll/fuse/fuse_intf.c

@@ -472,7 +472,8 @@ static NTSTATUS fsp_fuse_intf_GetSecurityEx(FSP_FILE_SYSTEM *FileSystem,
 
     if (0 != PSecurityDescriptorSize)
     {
-        Result = FspPosixMapPermissionsToSecurityDescriptor(Uid, Gid, Mode, &SecurityDescriptor);
+        Result = FspPosixMergePermissionsToSecurityDescriptor(Uid, Gid, Mode, f->FileSecurity,
+            &SecurityDescriptor);
         if (!NT_SUCCESS(Result))
             goto exit;
 
@@ -498,7 +499,7 @@ static NTSTATUS fsp_fuse_intf_GetSecurityEx(FSP_FILE_SYSTEM *FileSystem,
 exit:
     if (0 != SecurityDescriptor)
         FspDeleteSecurityDescriptor(SecurityDescriptor,
-            FspPosixMapPermissionsToSecurityDescriptor);
+            FspPosixMergePermissionsToSecurityDescriptor);
 
     return Result;
 }
@@ -1682,7 +1683,8 @@ static NTSTATUS fsp_fuse_intf_SetSecurity(FSP_FILE_SYSTEM *FileSystem,
     if (!NT_SUCCESS(Result))
         goto exit;
 
-    Result = FspPosixMapPermissionsToSecurityDescriptor(Uid, Gid, Mode, &SecurityDescriptor);
+    Result = FspPosixMergePermissionsToSecurityDescriptor(Uid, Gid, Mode, f->FileSecurity,
+        &SecurityDescriptor);
     if (!NT_SUCCESS(Result))
         goto exit;
 
@@ -1729,7 +1731,7 @@ exit:
 
     if (0 != SecurityDescriptor)
         FspDeleteSecurityDescriptor(SecurityDescriptor,
-            FspPosixMapPermissionsToSecurityDescriptor);
+            FspPosixMergePermissionsToSecurityDescriptor);
 
     return Result;
 }

src/dll/fuse/library.h

@@ -72,6 +72,8 @@ struct fuse
     FSP_FILE_SYSTEM *FileSystem;
     volatile int exited;
     struct fuse3 *fuse3;
+    PSECURITY_DESCRIPTOR FileSecurity;
+    FSP_FSCTL_DECLSPEC_ALIGN UINT8 FileSecurityBuf[];
 };
 struct fsp_fuse_context_header
 {
@@ -156,6 +158,8 @@ struct fsp_fuse_core_opt_data
     FSP_FSCTL_VOLUME_PARAMS VolumeParams;
     UINT16 VolumeLabelLength;
     WCHAR VolumeLabel[sizeof ((FSP_FSCTL_VOLUME_INFO *)0)->VolumeLabel / sizeof(WCHAR)];
+    ULONG FileSecuritySize;
+    FSP_FSCTL_DECLSPEC_ALIGN UINT8 FileSecurityBuf[1024];
 };
 FSP_FSCTL_STATIC_ASSERT(
     sizeof ((struct fuse *)0)->VolumeLabel == sizeof ((struct fsp_fuse_core_opt_data *)0)->VolumeLabel,

src/dll/np.c

@@ -742,7 +742,7 @@ DWORD APIENTRY NPAddConnection3(HWND hwndOwner,
     DWORD AuthPackage, CredentialsKind;
     WCHAR UserName[CREDUI_MAX_USERNAME_LENGTH + 1], Password[CREDUI_MAX_PASSWORD_LENGTH + 1];
 #if defined(FSP_NP_CREDENTIAL_MANAGER)
-    BOOL Save = TRUE;
+    BOOL Save = FALSE;
 #endif
 
     //dwFlags |= CONNECT_INTERACTIVE | CONNECT_PROMPT; /* TESTING ONLY! */

src/dll/security.c

@@ -488,7 +488,8 @@ FSP_API VOID FspDeleteSecurityDescriptor(PSECURITY_DESCRIPTOR SecurityDescriptor
         return;
 
     if ((NTSTATUS (*)())FspAccessCheckEx == CreateFunc ||
-        (NTSTATUS (*)())FspPosixMapPermissionsToSecurityDescriptor == CreateFunc)
+        (NTSTATUS (*)())FspPosixMapPermissionsToSecurityDescriptor == CreateFunc ||
+        (NTSTATUS (*)())FspPosixMergePermissionsToSecurityDescriptor == CreateFunc)
         MemFree(SecurityDescriptor);
     else
     if ((NTSTATUS (*)())FspCreateSecurityDescriptor == CreateFunc ||

src/dotnet/Interop.cs

@@ -315,7 +315,7 @@ namespace Fsp.Interop
     {
         internal const int FileNameBufSize = 1024 * 2/*FSP_FSCTL_TRANSACT_PATH_SIZEMAX*/;
         internal static int FileNameBufOffset =
-            (int)Marshal.OffsetOf(typeof(DirInfo), "FileNameBuf");
+            (int)Marshal.OffsetOf(typeof(NotifyInfoInternal), "FileNameBuf");
 
         internal UInt16 Size;
         internal UInt32 Filter;
@@ -337,6 +337,47 @@ namespace Fsp.Interop
         }
     }
 
+    /// <summary>
+    /// Enumeration of all the possible values for NotifyInfo.Action
+    /// </summary>
+    public enum NotifyAction : UInt32
+    {
+        Added = 1,
+        Removed = 2,
+        Modified = 3,
+        RenamedOldName = 4,
+        RenamedNewName = 5,
+        AddedStream = 6,
+        RemovedStream = 7,
+        ModifiedStream = 8,
+        RemovedByDelete = 9,
+        IdNotTunnelled = 10,
+        TunnelledIdCollision = 11,
+    }
+
+
+    /// <summary>
+    /// Enumeration of all the possible values for NotifyInfo.Filter
+    /// </summary>
+    [Flags]
+    public enum NotifyFilter : UInt32
+    {
+        None              = 0x00000,
+        ChangeFileName    = 0x00001,
+        ChangeDirName     = 0x00002,
+        ChangeName        = ChangeFileName | ChangeDirName,
+        ChangeAttributes  = 0x00004,
+        ChangeSize        = 0x00008,
+        ChangeLastWrite   = 0x00010,
+        ChangeLastAccess  = 0x00020,
+        ChangeCreation    = 0x00040,
+        ChangeEa          = 0x00080,
+        ChangeSecurity    = 0x00100,
+        ChangeStreamName  = 0x00200,
+        ChangeStreamSize  = 0x00400,
+        ChangeStreamWrite = 0x00800,
+    }
+
     /// <summary>
     /// Contains file change notification information.
     /// </summary>
@@ -344,8 +385,8 @@ namespace Fsp.Interop
     public struct NotifyInfo
     {
         public String FileName;
-        public UInt32 Action;
+        public NotifyAction Action;
-        public UInt32 Filter;
+        public NotifyFilter Filter;
     }
 
     [StructLayout(LayoutKind.Sequential)]
@@ -1147,10 +1188,11 @@ namespace Fsp.Interop
             int Length = 0;
             for (int I = 0; NotifyInfoArray.Length > I; I++)
             {
-                Length = (Length + 7) & ~7; // align to next qword boundary
                 Length += NotifyInfoInternal.FileNameBufOffset +
                     NotifyInfoArray[I].FileName.Length * 2;
+                Length = (Length + 7) & ~7; // align to next qword boundary
             }
+
             Byte[] Buffer = new Byte[Length];
             UInt32 BytesTransferred = default(UInt32);
             fixed (Byte *P = Buffer)
@@ -1158,8 +1200,8 @@ namespace Fsp.Interop
                 for (int I = 0; NotifyInfoArray.Length > I; I++)
                 {
                     NotifyInfoInternal Internal = default(NotifyInfoInternal);
-                    Internal.Action = NotifyInfoArray[I].Action;
+                    Internal.Action = (UInt32)NotifyInfoArray[I].Action;
-                    Internal.Filter = NotifyInfoArray[I].Filter;
+                    Internal.Filter = (UInt32)NotifyInfoArray[I].Filter;
                     Internal.SetFileNameBuf(NotifyInfoArray[I].FileName);
                     FspFileSystemAddNotifyInfo(
                         ref Internal, (IntPtr)P, (UInt32)Length, out BytesTransferred);

src/shared/ku/posix.c

@@ -41,6 +41,10 @@ FSP_API VOID FspDeleteSid(PSID Sid, NTSTATUS (*CreateFunc)());
 FSP_API NTSTATUS FspPosixMapPermissionsToSecurityDescriptor(
     UINT32 Uid, UINT32 Gid, UINT32 Mode,
     PSECURITY_DESCRIPTOR *PSecurityDescriptor);
+FSP_API NTSTATUS FspPosixMergePermissionsToSecurityDescriptor(
+    UINT32 Uid, UINT32 Gid, UINT32 Mode,
+    PSECURITY_DESCRIPTOR ExistingSecurityDescriptor,
+    PSECURITY_DESCRIPTOR *PSecurityDescriptor);
 FSP_API NTSTATUS FspPosixMapSecurityDescriptorToPermissions(
     PSECURITY_DESCRIPTOR SecurityDescriptor,
     PUINT32 PUid, PUINT32 PGid, PUINT32 PMode);
@@ -59,6 +63,7 @@ FSP_API VOID FspPosixDecodeWindowsPath(PWSTR WindowsPath, ULONG Size);
 #pragma alloc_text(PAGE, FspPosixCreateSid)
 #pragma alloc_text(PAGE, FspDeleteSid)
 #pragma alloc_text(PAGE, FspPosixMapPermissionsToSecurityDescriptor)
+#pragma alloc_text(PAGE, FspPosixMergePermissionsToSecurityDescriptor)
 #pragma alloc_text(PAGE, FspPosixMapSecurityDescriptorToPermissions)
 #pragma alloc_text(PAGE, FspPosixMapWindowsToPosixPathEx)
 #pragma alloc_text(PAGE, FspPosixMapPosixToWindowsPathEx)
@@ -898,6 +903,101 @@ lasterror:
     goto exit;
 }
 
+FSP_API NTSTATUS FspPosixMergePermissionsToSecurityDescriptor(
+    UINT32 Uid, UINT32 Gid, UINT32 Mode,
+    PSECURITY_DESCRIPTOR ExistingSecurityDescriptor,
+    PSECURITY_DESCRIPTOR *PSecurityDescriptor)
+{
+    FSP_KU_CODE;
+
+    if (0 == ExistingSecurityDescriptor)
+        return FspPosixMapPermissionsToSecurityDescriptor(Uid, Gid, Mode, PSecurityDescriptor);
+
+    PSID ExistingOwnerSid = 0, ExistingGroupSid = 0;
+    BOOL Defaulted, ExistingDaclPresent;
+    PACL ExistingAcl = 0;
+    PSID OwnerSid = 0, GroupSid = 0;
+    SECURITY_DESCRIPTOR SecurityDescriptor;
+    PSECURITY_DESCRIPTOR RelativeSecurityDescriptor = 0;
+    ULONG Size;
+    NTSTATUS Result;
+
+    *PSecurityDescriptor = 0;
+
+    if (!GetSecurityDescriptorOwner(ExistingSecurityDescriptor, &ExistingOwnerSid, &Defaulted))
+        goto lasterror;
+    if (!GetSecurityDescriptorGroup(ExistingSecurityDescriptor, &ExistingGroupSid, &Defaulted))
+        goto lasterror;
+    if (!GetSecurityDescriptorDacl(ExistingSecurityDescriptor, &ExistingDaclPresent, &ExistingAcl, &Defaulted))
+        goto lasterror;
+
+    if (0 == ExistingOwnerSid)
+    {
+        Result = FspPosixMapUidToSid(Uid, &OwnerSid);
+        if (!NT_SUCCESS(Result))
+            goto exit;
+        ExistingOwnerSid = OwnerSid;
+    }
+
+    if (0 == ExistingGroupSid)
+    {
+        Result = FspPosixMapUidToSid(Gid, &GroupSid);
+        if (!NT_SUCCESS(Result))
+            goto exit;
+        ExistingGroupSid = GroupSid;
+    }
+
+    if (!InitializeSecurityDescriptor(&SecurityDescriptor, SECURITY_DESCRIPTOR_REVISION))
+        goto lasterror;
+
+    if (!SetSecurityDescriptorOwner(&SecurityDescriptor, ExistingOwnerSid, FALSE))
+        goto lasterror;
+    if (!SetSecurityDescriptorGroup(&SecurityDescriptor, ExistingGroupSid, FALSE))
+        goto lasterror;
+    if (0 != ExistingAcl)
+    {
+        if (!SetSecurityDescriptorControl(&SecurityDescriptor, SE_DACL_PROTECTED, SE_DACL_PROTECTED))
+            goto lasterror;
+        if (!SetSecurityDescriptorDacl(&SecurityDescriptor, TRUE, ExistingAcl, FALSE))
+            goto lasterror;
+    }
+
+    Size = 0;
+    if (!MakeSelfRelativeSD(&SecurityDescriptor, 0, &Size) &&
+        ERROR_INSUFFICIENT_BUFFER != GetLastError())
+        goto lasterror;
+
+    RelativeSecurityDescriptor = MemAlloc(Size);
+    if (0 == RelativeSecurityDescriptor)
+    {
+        Result = STATUS_INSUFFICIENT_RESOURCES;
+        goto exit;
+    }
+
+    if (!MakeSelfRelativeSD(&SecurityDescriptor, RelativeSecurityDescriptor, &Size))
+        goto lasterror;
+
+    *PSecurityDescriptor = RelativeSecurityDescriptor;
+
+    Result = STATUS_SUCCESS;
+
+exit:
+    if (!NT_SUCCESS(Result))
+        MemFree(RelativeSecurityDescriptor);
+
+    if (0 != GroupSid)
+        FspDeleteSid(GroupSid, FspPosixMapUidToSid);
+
+    if (0 != OwnerSid)
+        FspDeleteSid(OwnerSid, FspPosixMapUidToSid);
+
+    return Result;
+
+lasterror:
+    Result = FspNtStatusFromWin32(GetLastError());
+    goto exit;
+}
+
 static inline ACCESS_MASK FspPosixCanonicalizeAccessMask(ACCESS_MASK AccessMask)
 {
     PGENERIC_MAPPING Mapping = FspGetFileGenericMapping();

src/sys/close.c

@@ -84,8 +84,9 @@ static NTSTATUS FspFsvolClose(
     FspFileDescDelete(FileDesc); /* this will also close the MainFileObject if any */
     FspFileNodeDereference(FileNode);
 
-    /* if we are closing files in the context of a rename make it synchronous */
+    /* if closing in the context of a rename or IOQ is above the watermark make it synchronous */
-    if (FspFsvolDeviceFileRenameIsAcquiredExclusive(FsvolDeviceObject))
+    if (FspFsvolDeviceFileRenameIsAcquiredExclusive(FsvolDeviceObject) ||
+        FspIoqPendingAboveWatermark(FspFsvolDeviceExtension(FsvolDeviceObject)->Ioq, 50))
     {
         /* acquire ownership of the Request */
         Request->Hint = (UINT_PTR)Irp;

src/sys/debug.c

@@ -22,6 +22,10 @@
 #include <sys/driver.h>
 
 #if DBG
+
+#undef STATUS_INSUFFICIENT_RESOURCES
+#define STATUS_INSUFFICIENT_RESOURCES   ((NTSTATUS)0xC000009AL)
+
 #define SYM(x)                          case x: return #x;
 #define SYMBRC(x)                       case x: return "[" #x "]";
 
@@ -330,4 +334,5 @@ VOID FspDebugLogIrp(const char *func, PIRP Irp, NTSTATUS Result)
         NtStatusSym(Result),
         (LONGLONG)Irp->IoStatus.Information);
 }
+
 #endif

src/sys/driver.c

@@ -38,6 +38,8 @@ NTSTATUS DriverEntry(
 {
     FSP_ENTER_DRV();
 
+    FSP_TRACE_INIT();
+
     /* setup the driver object */
     DriverObject->MajorFunction[IRP_MJ_CREATE] = FspCreate;
     DriverObject->MajorFunction[IRP_MJ_CLOSE] = FspClose;
@@ -157,6 +159,8 @@ exit:
             FspSiloFinalize();
         if (InitDoneGRes)
             ExDeleteResourceLite(&FspDeviceGlobalResource);
+
+        FSP_TRACE_FINI();
     }
 
 #pragma prefast(suppress:28175, "We are in DriverEntry: ok to access DriverName")

src/sys/driver.h

@@ -147,6 +147,40 @@ VOID FspDebugLogIrp(const char *func, PIRP Irp, NTSTATUS Result);
 #define DEBUGTEST_EX(C, Percent, Deflt) (Deflt)
 #endif
 
+/* trace */
+#if FSP_TRACE_ENABLED
+VOID FspTraceInitialize(VOID);
+VOID FspTraceFinalize(VOID);
+VOID FspTrace(const char *file, int line, const char *func);
+VOID FspTraceNtStatus(const char *file, int line, const char *func, NTSTATUS Status);
+#define FSP_TRACE_INIT()                \
+    FspTraceInitialize()
+#define FSP_TRACE_FINI()                \
+    FspTraceFinalize()
+#define FSP_TRACE()                     \
+    FspTrace(                           \
+        __FILE__,                       \
+        __LINE__,                       \
+        __FUNCTION__)
+#define FSP_TRACE_NTSTATUS(Status)      \
+    FspTraceNtStatus(                   \
+        __FILE__,                       \
+        __LINE__,                       \
+        __FUNCTION__,                   \
+        Status)
+#else
+#define FSP_TRACE_INIT()                \
+    ((VOID)0)
+#define FSP_TRACE_FINI()                \
+    ((VOID)0)
+#define FSP_TRACE()                     \
+    ((VOID)0)
+#define FSP_TRACE_NTSTATUS(Result)      \
+    ((VOID)0)
+#endif
+#undef STATUS_INSUFFICIENT_RESOURCES
+#define STATUS_INSUFFICIENT_RESOURCES   (FSP_TRACE_NTSTATUS(0xC000009AL), (NTSTATUS)0xC000009AL)
+
 /* FSP_ENTER/FSP_LEAVE */
 #if DBG
 #define FSP_DEBUGLOG_(fmt, rfmt, ...)   \
@@ -919,6 +953,7 @@ BOOLEAN FspIoqPostIrpEx(FSP_IOQ *Ioq, PIRP Irp, BOOLEAN BestEffort, NTSTATUS *PR
 PIRP FspIoqNextPendingIrp(FSP_IOQ *Ioq, PIRP BoundaryIrp, PLARGE_INTEGER Timeout,
     PIRP CancellableIrp);
 ULONG FspIoqPendingIrpCount(FSP_IOQ *Ioq);
+BOOLEAN FspIoqPendingAboveWatermark(FSP_IOQ *Ioq, ULONG Watermark);
 BOOLEAN FspIoqStartProcessingIrp(FSP_IOQ *Ioq, PIRP Irp);
 PIRP FspIoqEndProcessingIrp(FSP_IOQ *Ioq, UINT_PTR IrpHint);
 ULONG FspIoqProcessIrpCount(FSP_IOQ *Ioq);

src/sys/ioq.c

@@ -643,6 +643,16 @@ ULONG FspIoqPendingIrpCount(FSP_IOQ *Ioq)
     return Result;
 }
 
+BOOLEAN FspIoqPendingAboveWatermark(FSP_IOQ *Ioq, ULONG Watermark)
+{
+    BOOLEAN Result;
+    KIRQL Irql;
+    KeAcquireSpinLock(&Ioq->SpinLock, &Irql);
+    Result = Watermark < 100 * Ioq->PendingIrpCount / Ioq->PendingIrpCapacity;
+    KeReleaseSpinLock(&Ioq->SpinLock, Irql);
+    return Result;
+}
+
 BOOLEAN FspIoqStartProcessingIrp(FSP_IOQ *Ioq, PIRP Irp)
 {
     NTSTATUS Result;

src/sys/trace.c

@@ -0,0 +1,146 @@
+/**
+ * @file sys/trace.c
+ *
+ * @copyright 2015-2020 Bill Zissimopoulos
+ */
+/*
+ * This file is part of WinFsp.
+ *
+ * You can redistribute it and/or modify it under the terms of the GNU
+ * General Public License version 3 as published by the Free Software
+ * Foundation.
+ *
+ * Licensees holding a valid commercial license may use this software
+ * in accordance with the commercial license agreement provided in
+ * conjunction with the software.  The terms and conditions of any such
+ * commercial license agreement shall govern, supersede, and render
+ * ineffective any application of the GPLv3 license to this software,
+ * notwithstanding of any reference thereto in the software or
+ * associated repository.
+ */
+
+#include <sys/driver.h>
+
+#if FSP_TRACE_ENABLED
+
+#undef STATUS_INSUFFICIENT_RESOURCES
+#define STATUS_INSUFFICIENT_RESOURCES   ((NTSTATUS)0xC000009AL)
+
+static struct
+{
+    HANDLE Handle;
+    PKEVENT Event;
+} FspLowMemoryCondition, FspLowNonPagedPoolCondition, FspLowPagedPoolCondition;
+
+VOID FspTrace(const char *file, int line, const char *func)
+{
+    for (const char *p = file; '\0' != *p; p++)
+        if ('\\' == *p)
+            file = p + 1;
+
+    ASSERT(DISPATCH_LEVEL >= KeGetCurrentIrql());
+    DbgPrintEx(DPFLTR_DEFAULT_ID, DPFLTR_TRACE_LEVEL,
+        DRIVER_NAME ": %s[%s:%d]\n", func, file, line);
+}
+
+VOID FspTraceNtStatus(const char *file, int line, const char *func, NTSTATUS Status)
+{
+    for (const char *p = file; '\0' != *p; p++)
+        if ('\\' == *p)
+            file = p + 1;
+
+    ASSERT(DISPATCH_LEVEL >= KeGetCurrentIrql());
+    BOOLEAN LowMemoryCondition, LowNonPagedPoolCondition, LowPagedPoolCondition;
+    switch (Status)
+    {
+    case STATUS_INSUFFICIENT_RESOURCES:
+        LowMemoryCondition = 0 != FspLowMemoryCondition.Event &&
+            !!KeReadStateEvent(FspLowMemoryCondition.Event);
+        LowNonPagedPoolCondition = 0 != FspLowNonPagedPoolCondition.Event &&
+            !!KeReadStateEvent(FspLowNonPagedPoolCondition.Event);
+        LowPagedPoolCondition = 0 != FspLowPagedPoolCondition.Event &&
+            !!KeReadStateEvent(FspLowPagedPoolCondition.Event);
+        DbgPrintEx(DPFLTR_DEFAULT_ID, DPFLTR_TRACE_LEVEL,
+            DRIVER_NAME ": %s[%s:%d]: STATUS_INSUFFICIENT_RESOURCES (Memory=%c%c%c)\n",
+            func, file, line,
+            LowMemoryCondition ? 'M' : '-',
+            LowNonPagedPoolCondition ? 'N' : '-',
+            LowPagedPoolCondition ? 'P' : '-');
+        break;
+    default:
+        DbgPrintEx(DPFLTR_DEFAULT_ID, DPFLTR_TRACE_LEVEL,
+            DRIVER_NAME ": %s[%s:%d]: Status=%lx\n",
+            func, file, line,
+            Status);
+        break;
+    }
+}
+
+static PKEVENT FspOpenEvent(PWSTR Name, PHANDLE PHandle)
+{
+    UNICODE_STRING ObjectName;
+    OBJECT_ATTRIBUTES ObjectAttributes;
+    HANDLE Handle;
+    PKEVENT Event;
+    NTSTATUS Result;
+
+    *PHandle = 0;
+
+    RtlInitUnicodeString(&ObjectName, Name);
+    InitializeObjectAttributes(&ObjectAttributes,
+        &ObjectName, OBJ_KERNEL_HANDLE, 0, 0);
+    Result = ZwOpenEvent(&Handle,
+        EVENT_ALL_ACCESS, &ObjectAttributes);
+    if (!NT_SUCCESS(Result))
+        return 0;
+
+    Result = ObReferenceObjectByHandle(Handle,
+        0, *ExEventObjectType, KernelMode, &Event, 0);
+    if (!NT_SUCCESS(Result))
+    {
+        ZwClose(Handle);
+        return 0;
+    }
+
+    *PHandle = Handle;
+
+    return Event;
+}
+
+static VOID FspCloseEvent(PKEVENT Event, HANDLE Handle)
+{
+    if (0 != Event)
+        ObDereferenceObject(Event);
+
+    if (0 != Handle)
+        ZwClose(Handle);
+}
+
+VOID FspTraceInitialize(VOID)
+{
+#define OPEN_EVENT(NAME)                \
+    (Fsp ## NAME.Event = FspOpenEvent(L"\\KernelObjects\\" #NAME, &Fsp ## NAME.Handle))
+
+    OPEN_EVENT(LowMemoryCondition);
+    OPEN_EVENT(LowNonPagedPoolCondition);
+    OPEN_EVENT(LowPagedPoolCondition);
+
+#undef OPEN_EVENT
+
+    FSP_TRACE();
+}
+
+VOID FspTraceFinalize(VOID)
+{
+    FSP_TRACE();
+
+#define CLOSE_EVENT(NAME)               \
+    (FspCloseEvent(Fsp ## NAME.Event, Fsp ## NAME.Handle), Fsp ## NAME.Event = 0, Fsp ## NAME.Handle = 0)
+
+    CLOSE_EVENT(LowMemoryCondition);
+    CLOSE_EVENT(LowNonPagedPoolCondition);
+    CLOSE_EVENT(LowPagedPoolCondition);
+
+#undef CLOSE_EVENT
+}
+#endif

tst/notifyfs-dotnet/.gitignore

@@ -0,0 +1,9 @@
+build
+*.ncb
+*.suo
+*.vcproj.*
+*.vcxproj.user
+*.csproj.user
+*.VC.db
+*.VC.opendb
+.vs

tst/notifyfs-dotnet/Program.cs

@@ -0,0 +1,394 @@
+/**
+ * @file Program.cs
+ *
+ * @copyright 2015-2020 Bill Zissimopoulos
+ */
+/*
+ * This file is part of WinFsp.
+ *
+ * You can redistribute it and/or modify it under the terms of the GNU
+ * General Public License version 3 as published by the Free Software
+ * Foundation.
+ *
+ * Licensees holding a valid commercial license may use this software
+ * in accordance with the commercial license agreement provided in
+ * conjunction with the software.  The terms and conditions of any such
+ * commercial license agreement shall govern, supersede, and render
+ * ineffective any application of the GPLv3 license to this software,
+ * notwithstanding of any reference thereto in the software or
+ * associated repository.
+ */
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Security.AccessControl;
+using System.Text;
+using System.Threading;
+
+using Fsp;
+using VolumeInfo = Fsp.Interop.VolumeInfo;
+using FileInfo = Fsp.Interop.FileInfo;
+using NotifyInfo = Fsp.Interop.NotifyInfo;
+using NotifyAction = Fsp.Interop.NotifyAction;
+using NotifyFilter = Fsp.Interop.NotifyFilter;
+
+namespace notifyfs
+{
+    class Notifyfs : FileSystemBase
+    {
+        public override Int32 Init(Object Host)
+        {
+            _Host = (FileSystemHost)Host;
+            _Host.SectorSize = ALLOCATION_UNIT;
+            _Host.SectorsPerAllocationUnit = 1;
+            _Host.FileInfoTimeout = 1000;
+            _Host.CaseSensitiveSearch = false;
+            _Host.CasePreservedNames = true;
+            _Host.UnicodeOnDisk = true;
+            _Host.PersistentAcls = false;
+            _Host.PostCleanupWhenModifiedOnly = true;
+            _Host.VolumeCreationTime = 0;
+            _Host.VolumeSerialNumber = 0;
+
+            return STATUS_SUCCESS;
+        }
+        public override Int32 Mounted(Object Host)
+        {
+            _Timer = new Timer(this.Tick, null, 0, 1000);
+
+            return STATUS_SUCCESS;
+        }
+        public override void Unmounted(Object Host)
+        {
+            WaitHandle Event = new ManualResetEvent(false);
+            _Timer.Dispose(Event);
+            Event.WaitOne();
+        }
+        public override Int32 GetVolumeInfo(
+            out VolumeInfo VolumeInfo)
+        {
+            VolumeInfo = default(VolumeInfo);
+
+            return STATUS_SUCCESS;
+        }
+        public override Int32 GetSecurityByName(
+            String FileName,
+            out UInt32 FileAttributes/* or ReparsePointIndex */,
+            ref Byte[] SecurityDescriptor)
+        {
+            int Index = FileLookup(FileName);
+            if (-1 == Index)
+            {
+                FileAttributes = default(UInt32);
+                return STATUS_OBJECT_NAME_NOT_FOUND;
+            }
+
+            FileAttributes = 0 == Index ? (UInt32)System.IO.FileAttributes.Directory : 0;
+            if (null != SecurityDescriptor)
+                SecurityDescriptor = DefaultSecurity;
+
+            return STATUS_SUCCESS;
+        }
+        public override Int32 Open(
+            String FileName,
+            UInt32 CreateOptions,
+            UInt32 GrantedAccess,
+            out Object FileNode,
+            out Object FileDesc,
+            out FileInfo FileInfo,
+            out String NormalizedName)
+        {
+            FileNode = default(Object);
+            FileDesc = default(Object);
+            FileInfo = default(FileInfo);
+            NormalizedName = default(String);
+
+            int Index = FileLookup(FileName);
+            if (-1 == Index)
+                return STATUS_OBJECT_NAME_NOT_FOUND;
+
+            FileNode = Index;
+            FillFileInfo(Index, out FileInfo);
+
+            return STATUS_SUCCESS;
+        }
+        public override Int32 Read(
+            Object FileNode,
+            Object FileDesc,
+            IntPtr Buffer,
+            UInt64 Offset,
+            UInt32 Length,
+            out UInt32 BytesTransferred)
+        {
+            int Index = (int)FileNode;
+            UInt64 EndOffset;
+            Byte[] Contents = FileContents(Index);
+
+            if (Offset >= (UInt64)Contents.Length)
+            {
+                BytesTransferred = 0;
+                return STATUS_END_OF_FILE;
+            }
+
+            EndOffset = Offset + Length;
+            if (EndOffset > (UInt64)Contents.Length)
+                EndOffset = (UInt64)Contents.Length;
+
+            BytesTransferred = (UInt32)(EndOffset - Offset);
+            Marshal.Copy(Contents, (int)Offset, Buffer, (int)BytesTransferred);
+
+            return STATUS_SUCCESS;
+        }
+        public override Int32 GetFileInfo(
+            Object FileNode,
+            Object FileDesc,
+            out FileInfo FileInfo)
+        {
+            int Index = (int)FileNode;
+
+            FillFileInfo(Index, out FileInfo);
+
+            return STATUS_SUCCESS;
+        }
+        public override Boolean ReadDirectoryEntry(
+            Object FileNode,
+            Object FileDesc,
+            String Pattern,
+            String Marker,
+            ref Object Context,
+            out String FileName,
+            out FileInfo FileInfo)
+        {
+            IEnumerator<String> Enumerator = (IEnumerator<String>)Context;
+
+            if (null == Enumerator)
+            {
+                List<String> ChildrenFileNames = new List<String>();
+                for (int Index = 1, Count = FileCount(); Count >= Index; Index++)
+                    ChildrenFileNames.Add(String.Format("{0}", Index));
+                Context = Enumerator = ChildrenFileNames.GetEnumerator();
+            }
+
+            while (Enumerator.MoveNext())
+            {
+                FileName = Enumerator.Current;
+                FillFileInfo(int.Parse(FileName), out FileInfo);
+                return true;
+            }
+
+            FileName = default(String);
+            FileInfo = default(FileInfo);
+            return false;
+        }
+
+        private static int CountFromTicks(int Ticks)
+        {
+            /*
+             * The formula below produces the periodic sequence:
+             *     0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1,
+             *     0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1,
+             *     ...
+             */
+            int div10 = (Ticks % 20) / 10;
+            int mod10 = Ticks % 10;
+            int mdv10 = 1 - div10;
+            int mmd10 = 10 - mod10;
+            return mdv10 * mod10 + div10 * mmd10;
+        }
+        private int FileCount()
+        {
+            int Ticks = Thread.VolatileRead(ref _Ticks);
+            return CountFromTicks(Ticks);
+        }
+        private int FileLookup(String FileName)
+        {
+            FileName = FileName.Substring(1);
+            if ("" == FileName)
+                return 0;   /* root */
+            int Count = FileCount();
+            Boolean Valid = int.TryParse(FileName, out int Index);
+            if (!Valid || 0 >= Index || Index > Count)
+                return -1;  /* not found */
+            return Index;   /* regular file named 1, 2, ..., Count */
+        }
+        private static Byte[] FileContents(int Index)
+        {
+            if (0 == Index)
+                return EmptyByteArray;
+            return Encoding.UTF8.GetBytes(String.Format("{0}\n", Index));
+        }
+        private static void FillFileInfo(int Index, out FileInfo FileInfo)
+        {
+            FileInfo = default(FileInfo);
+            FileInfo.FileAttributes = 0 == Index ? (UInt32)System.IO.FileAttributes.Directory : 0;
+            FileInfo.FileSize = (UInt64)FileContents(Index).Length;
+            FileInfo.AllocationSize = (FileInfo.FileSize + ALLOCATION_UNIT - 1)
+                / ALLOCATION_UNIT * ALLOCATION_UNIT;
+            FileInfo.CreationTime =
+            FileInfo.LastAccessTime =
+            FileInfo.LastWriteTime =
+            FileInfo.ChangeTime = (UInt64)DateTime.Now.ToFileTimeUtc();
+        }
+        private void Tick(Object Context)
+        {
+            int Ticks = Interlocked.Increment(ref _Ticks);
+            int OldCount = CountFromTicks(Ticks - 1);
+            int NewCount = CountFromTicks(Ticks);
+            NotifyInfo[] NotifyInfo = new NotifyInfo[1];
+
+            if (OldCount < NewCount)
+            {
+                NotifyInfo[0].FileName = String.Format("\\{0}", NewCount);
+                NotifyInfo[0].Action = NotifyAction.Added;
+                NotifyInfo[0].Filter = NotifyFilter.ChangeFileName;
+                Console.Error.WriteLine("CREATE \\{0}", NewCount);
+            }
+            else if (OldCount > NewCount)
+            {
+                NotifyInfo[0].FileName = String.Format("\\{0}", OldCount);
+                NotifyInfo[0].Action = NotifyAction.Removed;
+                NotifyInfo[0].Filter = NotifyFilter.ChangeFileName;
+                Console.Error.WriteLine("REMOVE \\{0}", OldCount);
+            }
+
+            if (OldCount != NewCount)
+            {
+                if (STATUS_SUCCESS == _Host.NotifyBegin(500))
+                {
+                    _Host.Notify(NotifyInfo);
+                    _Host.NotifyEnd();
+                }
+            }
+        }
+
+        static Notifyfs()
+        {
+            RawSecurityDescriptor RootSecurityDescriptor = new RawSecurityDescriptor(
+                "O:BAG:BAD:P(A;;FA;;;SY)(A;;FA;;;BA)(A;;FA;;;WD)");
+            DefaultSecurity = new Byte[RootSecurityDescriptor.BinaryLength];
+            RootSecurityDescriptor.GetBinaryForm(DefaultSecurity, 0);
+        }
+
+        private const int ALLOCATION_UNIT = 4096;
+        private static readonly Byte[] EmptyByteArray = new Byte[0];
+        private static readonly Byte[] DefaultSecurity;
+        private FileSystemHost _Host;
+        private Timer _Timer;
+        private int _Ticks;
+    }
+
+    class NotifyfsService : Service
+    {
+        private class CommandLineUsageException : Exception
+        {
+            public CommandLineUsageException(String Message = null) : base(Message)
+            {
+                HasMessage = null != Message;
+            }
+
+            public bool HasMessage;
+        }
+
+        private const String PROGNAME = "notifyfs-dotnet";
+
+        public NotifyfsService() : base("NotifyfsService")
+        {
+        }
+
+        protected override void OnStart(String[] Args)
+        {
+            try
+            {
+                String VolumePrefix = null;
+                String MountPoint = null;
+                FileSystemHost Host = null;
+                Notifyfs Notifyfs = null;
+                int I;
+
+                for (I = 1; Args.Length > I; I++)
+                {
+                    String Arg = Args[I];
+                    if ('-' != Arg[0])
+                        break;
+                    switch (Arg[1])
+                    {
+                    case '?':
+                        throw new CommandLineUsageException();
+                    case 'm':
+                        argtos(Args, ref I, ref MountPoint);
+                        break;
+                    case 'u':
+                        argtos(Args, ref I, ref VolumePrefix);
+                        break;
+                    default:
+                        throw new CommandLineUsageException();
+                    }
+                }
+
+                if (Args.Length > I)
+                    throw new CommandLineUsageException();
+
+                if (null == MountPoint)
+                    throw new CommandLineUsageException();
+
+                FileSystemHost.SetDebugLogFile("-");
+
+                Host = new FileSystemHost(Notifyfs = new Notifyfs());
+                Host.Prefix = VolumePrefix;
+                if (0 > Host.Mount(MountPoint))
+                    throw new IOException("cannot mount file system");
+                MountPoint = Host.MountPoint();
+                _Host = Host;
+
+                Log(EVENTLOG_INFORMATION_TYPE, String.Format("{0}{1}{2} -m {3}",
+                    PROGNAME,
+                    null != VolumePrefix && 0 < VolumePrefix.Length ? " -u " : "",
+                        null != VolumePrefix && 0 < VolumePrefix.Length ? VolumePrefix : "",
+                    MountPoint));
+            }
+            catch (CommandLineUsageException ex)
+            {
+                Log(EVENTLOG_ERROR_TYPE, String.Format(
+                    "{0}" +
+                    "usage: {1} OPTIONS\n" +
+                    "\n" +
+                    "options:\n" +
+                    "    -u \\Server\\Share    [UNC prefix (single backslash)]\n" +
+                    "    -m MountPoint       [X:|*|directory]\n",
+                    ex.HasMessage ? ex.Message + "\n" : "",
+                    PROGNAME));
+                throw;
+            }
+            catch (Exception ex)
+            {
+                Log(EVENTLOG_ERROR_TYPE, String.Format("{0}", ex.Message));
+                throw;
+            }
+        }
+        protected override void OnStop()
+        {
+            _Host.Unmount();
+            _Host = null;
+        }
+
+        private static void argtos(String[] Args, ref int I, ref String V)
+        {
+            if (Args.Length > ++I)
+                V = Args[I];
+            else
+                throw new CommandLineUsageException();
+        }
+
+        private FileSystemHost _Host;
+    }
+
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            Environment.ExitCode = new NotifyfsService().Run();
+        }
+    }
+}

tst/notifyfs-dotnet/notifyfs-dotnet.csproj

@@ -0,0 +1,77 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{DA7C383A-D10F-4FB0-BDCB-E7A7C5D068AA}</ProjectGuid>
+    <OutputType>Exe</OutputType>
+    <RootNamespace>notifyfs</RootNamespace>
+    <AssemblyName>notifyfs-dotnet</AssemblyName>
+    <TargetFrameworkVersion>v4.5.2</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
+    <Deterministic>true</Deterministic>
+    <PublishUrl>publish\</PublishUrl>
+    <Install>true</Install>
+    <InstallFrom>Disk</InstallFrom>
+    <UpdateEnabled>false</UpdateEnabled>
+    <UpdateMode>Foreground</UpdateMode>
+    <UpdateInterval>7</UpdateInterval>
+    <UpdateIntervalUnits>Days</UpdateIntervalUnits>
+    <UpdatePeriodically>false</UpdatePeriodically>
+    <UpdateRequired>false</UpdateRequired>
+    <MapFileExtensions>true</MapFileExtensions>
+    <ApplicationRevision>0</ApplicationRevision>
+    <ApplicationVersion>1.0.0.%2a</ApplicationVersion>
+    <IsWebBootstrapper>false</IsWebBootstrapper>
+    <UseApplicationTrust>false</UseApplicationTrust>
+    <BootstrapperEnabled>true</BootstrapperEnabled>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>$(SolutionDir)build\$(Configuration)\</OutputPath>
+    <BaseIntermediateOutputPath>$(SolutionDir)build\$(ProjectName).build\</BaseIntermediateOutputPath>
+    <IntermediateOutputPath>$(BaseIntermediateOutputPath)$(Configuration)\</IntermediateOutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <Prefer32Bit>false</Prefer32Bit>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>$(SolutionDir)build\$(Configuration)\</OutputPath>
+    <BaseIntermediateOutputPath>$(SolutionDir)build\$(ProjectName).build\</BaseIntermediateOutputPath>
+    <IntermediateOutputPath>$(BaseIntermediateOutputPath)$(Configuration)\</IntermediateOutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="Program.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="winfsp-msil">
+      <HintPath>$(MSBuildProgramFiles32)\WinFsp\bin\winfsp-msil.dll</HintPath>
+    </Reference>
+  </ItemGroup>
+  <ItemGroup>
+    <BootstrapperPackage Include=".NETFramework,Version=v4.5.2">
+      <Visible>False</Visible>
+      <ProductName>Microsoft .NET Framework 4.5.2 %28x86 and x64%29</ProductName>
+      <Install>true</Install>
+    </BootstrapperPackage>
+    <BootstrapperPackage Include="Microsoft.Net.Framework.3.5.SP1">
+      <Visible>False</Visible>
+      <ProductName>.NET Framework 3.5 SP1</ProductName>
+      <Install>false</Install>
+    </BootstrapperPackage>
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+</Project>

tst/notifyfs-dotnet/notifyfs-dotnet.sln

@@ -0,0 +1,25 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.30717.126
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "notifyfs-dotnet", "notifyfs-dotnet.csproj", "{DA7C383A-D10F-4FB0-BDCB-E7A7C5D068AA}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{DA7C383A-D10F-4FB0-BDCB-E7A7C5D068AA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{DA7C383A-D10F-4FB0-BDCB-E7A7C5D068AA}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{DA7C383A-D10F-4FB0-BDCB-E7A7C5D068AA}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{DA7C383A-D10F-4FB0-BDCB-E7A7C5D068AA}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {18D87005-09CA-40CF-9B51-139B486AB8D0}
+	EndGlobalSection
+EndGlobal

tst/notifyfs/.gitignore

@@ -0,0 +1,8 @@
+build
+*.ncb
+*.suo
+*.vcproj.*
+*.vcxproj.user
+*.VC.db
+*.VC.opendb
+.vs

tst/notifyfs/notifyfs.c

@@ -0,0 +1,508 @@
+/**
+ * @file notifyfs.c
+ *
+ * @copyright 2015-2020 Bill Zissimopoulos
+ */
+/*
+ * This file is part of WinFsp.
+ *
+ * You can redistribute it and/or modify it under the terms of the GNU
+ * General Public License version 3 as published by the Free Software
+ * Foundation.
+ *
+ * Licensees holding a valid commercial license may use this software
+ * in accordance with the commercial license agreement provided in
+ * conjunction with the software.  The terms and conditions of any such
+ * commercial license agreement shall govern, supersede, and render
+ * ineffective any application of the GPLv3 license to this software,
+ * notwithstanding of any reference thereto in the software or
+ * associated repository.
+ */
+
+#include <winfsp/winfsp.h>
+#include <sddl.h>
+
+#define DEBUGFLAGS                      0
+//#define DEBUGFLAGS                      -1
+
+#define PROGNAME                        "notifyfs"
+#define ALLOCATION_UNIT                 4096
+
+#define info(format, ...)               FspServiceLog(EVENTLOG_INFORMATION_TYPE, format, __VA_ARGS__)
+#define warn(format, ...)               FspServiceLog(EVENTLOG_WARNING_TYPE, format, __VA_ARGS__)
+#define fail(format, ...)               FspServiceLog(EVENTLOG_ERROR_TYPE, format, __VA_ARGS__)
+
+typedef struct
+{
+    FSP_FILE_SYSTEM *FileSystem;
+    PTP_TIMER Timer;
+    UINT32 Ticks;
+} NOTIFYFS;
+
+static PSECURITY_DESCRIPTOR DefaultSecurity;
+static ULONG DefaultSecuritySize;
+
+static UINT32 CountFromTicks(UINT32 Ticks)
+{
+    /*
+     * The formula below produces the periodic sequence:
+     *     0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1,
+     *     0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1,
+     *     ...
+     */
+    UINT32 div10 = (Ticks % 20) / 10;
+    UINT32 mod10 = Ticks % 10;
+    UINT32 mdv10 = 1 - div10;
+    UINT32 mmd10 = 10 - mod10;
+    return mdv10 * mod10 + div10 * mmd10;
+}
+
+static UINT32 FileCount(NOTIFYFS *Notifyfs)
+{
+    UINT32 Ticks = InterlockedOr(&Notifyfs->Ticks, 0);
+    return CountFromTicks(Ticks);
+}
+
+static UINT32 FileLookup(NOTIFYFS *Notifyfs, PWSTR FileName)
+{
+    FileName++;
+    PWSTR Endp;
+    UINT32 Count = FileCount(Notifyfs);
+    UINT32 Index = wcstoul(FileName, &Endp, 10);
+    if ('\0' != *Endp || (FileName != Endp && (0 == Index || Index > Count)))
+        return -1;  /* not found */
+    if (FileName == Endp)
+        return 0;   /* root */
+    return Index;   /* regular file named 1, 2, ..., Count */
+}
+
+static UINT32 FileContents(UINT32 Index, WCHAR P[32])
+{
+    WCHAR Buffer[32];
+    if (0 == P)
+        P = Buffer;
+    if (0 == Index)
+        P[0] = '\0';
+    else
+        wsprintfW(P, L"%u\n", (unsigned)Index);
+    return lstrlenW(P);
+}
+
+static VOID FillFileInfo(UINT32 Index, FSP_FSCTL_FILE_INFO *FileInfo)
+{
+    FILETIME SystemTime;
+
+    GetSystemTimeAsFileTime(&SystemTime);
+
+    memset(FileInfo, 0, sizeof FileInfo);
+    FileInfo->FileAttributes = 0 == Index ? FILE_ATTRIBUTE_DIRECTORY : 0;
+    FileInfo->FileSize = FileContents(Index, 0);
+    FileInfo->AllocationSize = (FileInfo->FileSize + ALLOCATION_UNIT - 1)
+        / ALLOCATION_UNIT * ALLOCATION_UNIT;
+    FileInfo->CreationTime =
+    FileInfo->LastAccessTime =
+    FileInfo->LastWriteTime =
+    FileInfo->ChangeTime = *(PUINT64)&SystemTime;
+}
+
+static BOOLEAN AddDirInfo(PWSTR FileName, UINT32 Index,
+    PVOID Buffer, ULONG Length, PULONG PBytesTransferred)
+{
+    union
+    {
+        UINT8 B[FIELD_OFFSET(FSP_FSCTL_DIR_INFO, FileNameBuf) + MAX_PATH * sizeof(WCHAR)];
+        FSP_FSCTL_DIR_INFO D;
+    } DirInfoBuf;
+    FSP_FSCTL_DIR_INFO *DirInfo = &DirInfoBuf.D;
+
+    memset(DirInfo->Padding, 0, sizeof DirInfo->Padding);
+    if (0 != FileName)
+        lstrcpyW(DirInfo->FileNameBuf, FileName);
+    else
+        wsprintfW(DirInfo->FileNameBuf, L"%u", (unsigned)Index);
+    DirInfo->Size = (UINT16)(sizeof(FSP_FSCTL_DIR_INFO) + wcslen(DirInfo->FileNameBuf) * sizeof(WCHAR));
+    FillFileInfo(Index, &DirInfo->FileInfo);
+
+    return FspFileSystemAddDirInfo(DirInfo, Buffer, Length, PBytesTransferred);
+}
+
+static NTSTATUS GetVolumeInfo(FSP_FILE_SYSTEM *FileSystem,
+    FSP_FSCTL_VOLUME_INFO *VolumeInfo)
+{
+    memset(VolumeInfo, 0, sizeof *VolumeInfo);
+
+    return STATUS_SUCCESS;
+}
+
+static NTSTATUS GetSecurityByName(FSP_FILE_SYSTEM *FileSystem,
+    PWSTR FileName, PUINT32 PFileAttributes,
+    PSECURITY_DESCRIPTOR SecurityDescriptor, SIZE_T *PSecurityDescriptorSize)
+{
+    NOTIFYFS *Notifyfs = (NOTIFYFS *)FileSystem->UserContext;
+    UINT32 Index;
+
+    Index = FileLookup(Notifyfs, FileName);
+    if (-1 == Index)
+        return STATUS_OBJECT_NAME_NOT_FOUND;
+
+    if (0 != PFileAttributes)
+        *PFileAttributes = 0 == Index ? FILE_ATTRIBUTE_DIRECTORY : 0;
+
+    if (0 != PSecurityDescriptorSize)
+    {
+        if (DefaultSecuritySize > *PSecurityDescriptorSize)
+        {
+            *PSecurityDescriptorSize = DefaultSecuritySize;
+            return STATUS_BUFFER_OVERFLOW;
+        }
+
+        *PSecurityDescriptorSize = DefaultSecuritySize;
+        if (0 != SecurityDescriptor)
+            memcpy(SecurityDescriptor, DefaultSecurity, DefaultSecuritySize);
+    }
+
+    return STATUS_SUCCESS;
+}
+
+static NTSTATUS Create(FSP_FILE_SYSTEM *FileSystem,
+    PWSTR FileName, UINT32 CreateOptions, UINT32 GrantedAccess,
+    UINT32 FileAttributes, PSECURITY_DESCRIPTOR SecurityDescriptor, UINT64 AllocationSize,
+    PVOID *PFileContext, FSP_FSCTL_FILE_INFO *FileInfo)
+{
+    return STATUS_INVALID_DEVICE_REQUEST;
+}
+
+static NTSTATUS Open(FSP_FILE_SYSTEM *FileSystem,
+    PWSTR FileName, UINT32 CreateOptions, UINT32 GrantedAccess,
+    PVOID *PFileContext, FSP_FSCTL_FILE_INFO *FileInfo)
+{
+    NOTIFYFS *Notifyfs = (NOTIFYFS *)FileSystem->UserContext;
+    FSP_FSCTL_TRANSACT_FULL_CONTEXT *FullContext = (PVOID)PFileContext;
+    UINT32 Index;
+
+    Index = FileLookup(Notifyfs, FileName);
+    if (-1 == Index)
+        return STATUS_OBJECT_NAME_NOT_FOUND;
+
+    FullContext->UserContext = Index;
+    FullContext->UserContext2 = 0;
+
+    FillFileInfo(Index, FileInfo);
+
+    return STATUS_SUCCESS;
+}
+
+static NTSTATUS Overwrite(FSP_FILE_SYSTEM *FileSystem,
+    PVOID FileContext, UINT32 FileAttributes, BOOLEAN ReplaceFileAttributes, UINT64 AllocationSize,
+    FSP_FSCTL_FILE_INFO *FileInfo)
+{
+    return STATUS_INVALID_DEVICE_REQUEST;
+}
+
+static NTSTATUS Read(FSP_FILE_SYSTEM *FileSystem,
+    PVOID FileContext, PVOID Buffer, UINT64 Offset, ULONG Length,
+    PULONG PBytesTransferred)
+{
+    NOTIFYFS *Notifyfs = (NOTIFYFS *)FileSystem->UserContext;
+    FSP_FSCTL_TRANSACT_FULL_CONTEXT *FullContext = FileContext;
+    UINT32 Index = (UINT32)FullContext->UserContext;
+    UINT64 EndOffset;
+    WCHAR ContentBuf[32];
+    UINT32 ContentLen;
+
+    ContentLen = FileContents(Index, ContentBuf);
+
+    if (Offset >= ContentLen)
+        return STATUS_END_OF_FILE;
+
+    EndOffset = Offset + Length;
+    if (EndOffset > ContentLen)
+        EndOffset = ContentLen;
+
+    memcpy(Buffer, (PUINT8)ContentBuf + Offset, (size_t)(EndOffset - Offset));
+
+    *PBytesTransferred = (ULONG)(EndOffset - Offset);
+
+    return STATUS_SUCCESS;
+}
+
+static NTSTATUS GetFileInfo(FSP_FILE_SYSTEM *FileSystem,
+    PVOID FileContext,
+    FSP_FSCTL_FILE_INFO *FileInfo)
+{
+    NOTIFYFS *Notifyfs = (NOTIFYFS *)FileSystem->UserContext;
+    FSP_FSCTL_TRANSACT_FULL_CONTEXT *FullContext = FileContext;
+    UINT32 Index = (UINT32)FullContext->UserContext;
+
+    FillFileInfo(Index, FileInfo);
+
+    return STATUS_SUCCESS;
+}
+
+static NTSTATUS ReadDirectory(FSP_FILE_SYSTEM *FileSystem,
+    PVOID FileContext, PWSTR Pattern, PWSTR Marker,
+    PVOID Buffer, ULONG Length, PULONG PBytesTransferred)
+{
+    NOTIFYFS *Notifyfs = (NOTIFYFS *)FileSystem->UserContext;
+    UINT32 Count = FileCount(Notifyfs);
+    UINT32 Index;
+
+    Index = 0 == Marker ? 1 : wcstoul(Marker, 0, 10) + 1;
+    for (; Count >= Index; Index++)
+        if (!AddDirInfo(0, Index, Buffer, Length, PBytesTransferred))
+            break;
+    FspFileSystemAddDirInfo(0, Buffer, Length, PBytesTransferred);
+
+    return STATUS_SUCCESS;
+}
+
+static FSP_FILE_SYSTEM_INTERFACE NotifyfsInterface =
+{
+    .GetVolumeInfo = GetVolumeInfo,
+    .GetSecurityByName = GetSecurityByName,
+    .Create = Create,
+    .Open = Open,
+    .Overwrite = Overwrite,
+    .Read = Read,
+    .GetFileInfo = GetFileInfo,
+    .ReadDirectory = ReadDirectory,
+};
+
+static VOID CALLBACK NotifyfsTick(PTP_CALLBACK_INSTANCE Instance, PVOID Context, PTP_TIMER Timer)
+{
+    NOTIFYFS *Notifyfs = Context;
+    UINT32 Ticks = InterlockedIncrement(&Notifyfs->Ticks);
+    UINT32 OldCount = CountFromTicks(Ticks - 1);
+    UINT32 NewCount = CountFromTicks(Ticks);
+    union
+    {
+        UINT8 B[FIELD_OFFSET(FSP_FSCTL_NOTIFY_INFO, FileNameBuf) + MAX_PATH * sizeof(WCHAR)];
+        FSP_FSCTL_NOTIFY_INFO V;
+    } NotifyInfoBuf;
+    FSP_FSCTL_NOTIFY_INFO *NotifyInfo = &NotifyInfoBuf.V;
+
+    memset(NotifyInfo, 0, sizeof NotifyInfo);
+    if (OldCount < NewCount)
+    {
+        wsprintfW(NotifyInfo->FileNameBuf, L"\\%u", (unsigned)NewCount);
+        NotifyInfo->Size = (UINT16)(sizeof(FSP_FSCTL_NOTIFY_INFO) +
+            wcslen(NotifyInfo->FileNameBuf) * sizeof(WCHAR));
+        NotifyInfo->Action = FILE_ACTION_ADDED;
+        NotifyInfo->Filter = FILE_NOTIFY_CHANGE_FILE_NAME;
+        FspDebugLog("CREATE \\%u\n", (unsigned)NewCount);
+    }
+    else if (OldCount > NewCount)
+    {
+        wsprintfW(NotifyInfo->FileNameBuf, L"\\%u", (unsigned)OldCount);
+        NotifyInfo->Size = (UINT16)(sizeof(FSP_FSCTL_NOTIFY_INFO) +
+            wcslen(NotifyInfo->FileNameBuf) * sizeof(WCHAR));
+        NotifyInfo->Action = FILE_ACTION_REMOVED;
+        NotifyInfo->Filter = FILE_NOTIFY_CHANGE_FILE_NAME;
+        FspDebugLog("REMOVE \\%u\n", (unsigned)OldCount);
+    }
+
+    if (OldCount != NewCount)
+    {
+        if (STATUS_SUCCESS == FspFileSystemNotifyBegin(Notifyfs->FileSystem, 500))
+        {
+            FspFileSystemNotify(Notifyfs->FileSystem, NotifyInfo, NotifyInfo->Size);
+            FspFileSystemNotifyEnd(Notifyfs->FileSystem);
+        }
+    }
+}
+
+static VOID NotifyfsDelete(NOTIFYFS *Notifyfs);
+
+static NTSTATUS NotifyfsCreate(PWSTR VolumePrefix, PWSTR MountPoint, NOTIFYFS **PNotifyfs)
+{
+    FSP_FSCTL_VOLUME_PARAMS VolumeParams;
+    NOTIFYFS *Notifyfs = 0;
+    INT64 TimerDue;
+    NTSTATUS Result;
+
+    *PNotifyfs = 0;
+
+    if (!ConvertStringSecurityDescriptorToSecurityDescriptorW(
+        L"O:BAG:BAD:P(A;;FA;;;SY)(A;;FA;;;BA)(A;;FA;;;WD)", SDDL_REVISION_1,
+        &DefaultSecurity, &DefaultSecuritySize))
+    {
+        Result = FspNtStatusFromWin32(GetLastError());
+        goto exit;
+    }
+
+    Notifyfs = malloc(sizeof *Notifyfs);
+    if (0 == Notifyfs)
+    {
+        Result = STATUS_INSUFFICIENT_RESOURCES;
+        goto exit;
+    }
+    memset(Notifyfs, 0, sizeof *Notifyfs);
+
+    memset(&VolumeParams, 0, sizeof VolumeParams);
+    VolumeParams.SectorSize = ALLOCATION_UNIT;
+    VolumeParams.SectorsPerAllocationUnit = 1;
+    VolumeParams.VolumeCreationTime = 0;
+    VolumeParams.VolumeSerialNumber = 0;
+    VolumeParams.FileInfoTimeout = 1000;
+    VolumeParams.CaseSensitiveSearch = 0;
+    VolumeParams.CasePreservedNames = 1;
+    VolumeParams.UnicodeOnDisk = 1;
+    VolumeParams.PersistentAcls = 0;
+    VolumeParams.PostCleanupWhenModifiedOnly = 1;
+    VolumeParams.UmFileContextIsFullContext = 1;
+    if (0 != VolumePrefix)
+        wcscpy_s(VolumeParams.Prefix, sizeof VolumeParams.Prefix / sizeof(WCHAR), VolumePrefix);
+    wcscpy_s(VolumeParams.FileSystemName, sizeof VolumeParams.FileSystemName / sizeof(WCHAR),
+        L"" PROGNAME);
+
+    Result = FspFileSystemCreate(
+        VolumeParams.Prefix[0] ? L"" FSP_FSCTL_NET_DEVICE_NAME : L"" FSP_FSCTL_DISK_DEVICE_NAME,
+        &VolumeParams,
+        &NotifyfsInterface,
+        &Notifyfs->FileSystem);
+    if (!NT_SUCCESS(Result))
+        goto exit;
+    Notifyfs->FileSystem->UserContext = Notifyfs;
+
+    FspFileSystemSetDebugLog(Notifyfs->FileSystem, DEBUGFLAGS);
+
+    Result = FspFileSystemSetMountPoint(Notifyfs->FileSystem, MountPoint);
+    if (!NT_SUCCESS(Result))
+        goto exit;
+
+    Notifyfs->Timer = CreateThreadpoolTimer(NotifyfsTick, Notifyfs, 0);
+    if (0 == Notifyfs->Timer)
+    {
+        Result = FspNtStatusFromWin32(GetLastError());
+        goto exit;
+    }
+
+    TimerDue = -1000;
+    SetThreadpoolTimer(Notifyfs->Timer, (PVOID)&TimerDue, 1000, 0);
+
+    Result = STATUS_SUCCESS;
+
+exit:
+    if (NT_SUCCESS(Result))
+        *PNotifyfs = Notifyfs;
+    else if (0 != Notifyfs)
+        NotifyfsDelete(Notifyfs);
+
+    return Result;
+}
+
+static VOID NotifyfsDelete(NOTIFYFS *Notifyfs)
+{
+    if (0 != Notifyfs->Timer)
+    {
+        SetThreadpoolTimer(Notifyfs->Timer, 0, 0, 0);
+        WaitForThreadpoolTimerCallbacks(Notifyfs->Timer, TRUE);
+        CloseThreadpoolTimer(Notifyfs->Timer);
+    }
+
+    if (0 != Notifyfs->FileSystem)
+        FspFileSystemDelete(Notifyfs->FileSystem);
+
+    free(Notifyfs);
+}
+
+static NTSTATUS SvcStart(FSP_SERVICE *Service, ULONG argc, PWSTR *argv)
+{
+#define argtos(v)                       if (arge > ++argp) v = *argp; else goto usage
+
+    wchar_t **argp, **arge;
+    PWSTR VolumePrefix = 0;
+    PWSTR MountPoint = 0;
+    NOTIFYFS *Notifyfs = 0;
+    NTSTATUS Result;
+
+    for (argp = argv + 1, arge = argv + argc; arge > argp; argp++)
+    {
+        if (L'-' != argp[0][0])
+            break;
+        switch (argp[0][1])
+        {
+        case L'?':
+            goto usage;
+        case L'm':
+            argtos(MountPoint);
+            break;
+        case L'u':
+            argtos(VolumePrefix);
+            break;
+        default:
+            goto usage;
+        }
+    }
+
+    if (arge > argp)
+        goto usage;
+
+    if (0 == MountPoint)
+        goto usage;
+
+    FspDebugLogSetHandle(GetStdHandle(STD_ERROR_HANDLE));
+
+    Result = NotifyfsCreate(VolumePrefix, MountPoint, &Notifyfs);
+    if (!NT_SUCCESS(Result))
+    {
+        fail(L"cannot create file system");
+        goto exit;
+    }
+
+    Result = FspFileSystemStartDispatcher(Notifyfs->FileSystem, 0);
+    if (!NT_SUCCESS(Result))
+    {
+        fail(L"cannot start file system");
+        goto exit;
+    }
+
+    MountPoint = FspFileSystemMountPoint(Notifyfs->FileSystem);
+
+    info(L"%s%s%s -m %s",
+        L"" PROGNAME,
+        0 != VolumePrefix && L'\0' != VolumePrefix[0] ? L" -u " : L"",
+            0 != VolumePrefix && L'\0' != VolumePrefix[0] ? VolumePrefix : L"",
+        MountPoint);
+
+    Service->UserContext = Notifyfs;
+    Result = STATUS_SUCCESS;
+
+exit:
+    if (!NT_SUCCESS(Result) && 0 != Notifyfs)
+        NotifyfsDelete(Notifyfs);
+
+    return Result;
+
+usage:;
+    static wchar_t usage[] = L""
+        "usage: %s OPTIONS\n"
+        "\n"
+        "options:\n"
+        "    -u \\Server\\Share    [UNC prefix (single backslash)]\n"
+        "    -m MountPoint       [X:|*|directory]\n";
+
+    fail(usage, L"" PROGNAME);
+
+    return STATUS_UNSUCCESSFUL;
+
+#undef argtos
+}
+
+static NTSTATUS SvcStop(FSP_SERVICE *Service)
+{
+    NOTIFYFS *Notifyfs = Service->UserContext;
+
+    FspFileSystemStopDispatcher(Notifyfs->FileSystem);
+    NotifyfsDelete(Notifyfs);
+
+    return STATUS_SUCCESS;
+}
+
+int wmain(int argc, wchar_t **argv)
+{
+    if (!NT_SUCCESS(FspLoad(0)))
+        return ERROR_DELAY_LOAD_FAILED;
+
+    return FspServiceRun(L"" PROGNAME, SvcStart, SvcStop, 0);
+}

tst/notifyfs/notifyfs.sln

@@ -0,0 +1,31 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.30717.126
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "notifyfs", "notifyfs.vcxproj", "{4BA1DED0-4268-408A-A4E2-8E1A6D55A99C}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|x64 = Debug|x64
+		Debug|x86 = Debug|x86
+		Release|x64 = Release|x64
+		Release|x86 = Release|x86
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{4BA1DED0-4268-408A-A4E2-8E1A6D55A99C}.Debug|x64.ActiveCfg = Debug|x64
+		{4BA1DED0-4268-408A-A4E2-8E1A6D55A99C}.Debug|x64.Build.0 = Debug|x64
+		{4BA1DED0-4268-408A-A4E2-8E1A6D55A99C}.Debug|x86.ActiveCfg = Debug|Win32
+		{4BA1DED0-4268-408A-A4E2-8E1A6D55A99C}.Debug|x86.Build.0 = Debug|Win32
+		{4BA1DED0-4268-408A-A4E2-8E1A6D55A99C}.Release|x64.ActiveCfg = Release|x64
+		{4BA1DED0-4268-408A-A4E2-8E1A6D55A99C}.Release|x64.Build.0 = Release|x64
+		{4BA1DED0-4268-408A-A4E2-8E1A6D55A99C}.Release|x86.ActiveCfg = Release|Win32
+		{4BA1DED0-4268-408A-A4E2-8E1A6D55A99C}.Release|x86.Build.0 = Release|Win32
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {3CD0763B-2BFD-4D73-9539-13273788C41E}
+	EndGlobalSection
+EndGlobal

tst/notifyfs/notifyfs.vcxproj

@@ -0,0 +1,175 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|x64">
+      <Configuration>Debug</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|x64">
+      <Configuration>Release</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <VCProjectVersion>16.0</VCProjectVersion>
+    <Keyword>Win32Proj</Keyword>
+    <ProjectGuid>{4ba1ded0-4268-408a-a4e2-8e1a6d55a99c}</ProjectGuid>
+    <RootNamespace>notifyfs</RootNamespace>
+    <WindowsTargetPlatformVersion>$(LatestTargetPlatformVersion)</WindowsTargetPlatformVersion>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>$(DefaultPlatformToolset)</PlatformToolset>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <PlatformToolset>$(DefaultPlatformToolset)</PlatformToolset>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>$(DefaultPlatformToolset)</PlatformToolset>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <PlatformToolset>$(DefaultPlatformToolset)</PlatformToolset>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="Shared">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+    <OutDir>$(SolutionDir)build\$(Configuration)\</OutDir>
+    <IntDir>$(SolutionDir)build\$(ProjectName).build\$(Configuration)\$(PlatformTarget)\</IntDir>
+    <TargetName>$(ProjectName)-$(PlatformTarget)</TargetName>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+    <OutDir>$(SolutionDir)build\$(Configuration)\</OutDir>
+    <IntDir>$(SolutionDir)build\$(ProjectName).build\$(Configuration)\$(PlatformTarget)\</IntDir>
+    <TargetName>$(ProjectName)-$(PlatformTarget)</TargetName>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <LinkIncremental>true</LinkIncremental>
+    <OutDir>$(SolutionDir)build\$(Configuration)\</OutDir>
+    <IntDir>$(SolutionDir)build\$(ProjectName).build\$(Configuration)\$(PlatformTarget)\</IntDir>
+    <TargetName>$(ProjectName)-$(PlatformTarget)</TargetName>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <LinkIncremental>false</LinkIncremental>
+    <OutDir>$(SolutionDir)build\$(Configuration)\</OutDir>
+    <IntDir>$(SolutionDir)build\$(ProjectName).build\$(Configuration)\$(PlatformTarget)\</IntDir>
+    <TargetName>$(ProjectName)-$(PlatformTarget)</TargetName>
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
+      <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ConformanceMode>true</ConformanceMode>
+      <AdditionalIncludeDirectories>$(MSBuildProgramFiles32)\WinFsp\inc</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>$(MSBuildProgramFiles32)\WinFsp\lib\winfsp-$(PlatformTarget).lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <DelayLoadDLLs>winfsp-$(PlatformTarget).dll</DelayLoadDLLs>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <WarningLevel>Level3</WarningLevel>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <SDLCheck>true</SDLCheck>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ConformanceMode>true</ConformanceMode>
+      <AdditionalIncludeDirectories>$(MSBuildProgramFiles32)\WinFsp\inc</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>$(MSBuildProgramFiles32)\WinFsp\lib\winfsp-$(PlatformTarget).lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <DelayLoadDLLs>winfsp-$(PlatformTarget).dll</DelayLoadDLLs>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <ClCompile>
+      <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
+      <PreprocessorDefinitions>_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ConformanceMode>true</ConformanceMode>
+      <AdditionalIncludeDirectories>$(MSBuildProgramFiles32)\WinFsp\inc</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>$(MSBuildProgramFiles32)\WinFsp\lib\winfsp-$(PlatformTarget).lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <DelayLoadDLLs>winfsp-$(PlatformTarget).dll</DelayLoadDLLs>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <ClCompile>
+      <WarningLevel>Level3</WarningLevel>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <SDLCheck>true</SDLCheck>
+      <PreprocessorDefinitions>NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ConformanceMode>true</ConformanceMode>
+      <AdditionalIncludeDirectories>$(MSBuildProgramFiles32)\WinFsp\inc</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>$(MSBuildProgramFiles32)\WinFsp\lib\winfsp-$(PlatformTarget).lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <DelayLoadDLLs>winfsp-$(PlatformTarget).dll</DelayLoadDLLs>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemGroup>
+    <ClCompile Include="notifyfs.c" />
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>

tst/notifyfs/notifyfs.vcxproj.filters

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <Filter Include="Source">
+      <UniqueIdentifier>{4FC737F1-C7A5-4376-A066-2A32D752A2FF}</UniqueIdentifier>
+      <Extensions>cpp;c;cc;cxx;c++;cppm;ixx;def;odl;idl;hpj;bat;asm;asmx</Extensions>
+    </Filter>
+  </ItemGroup>
+  <ItemGroup>
+    <ClCompile Include="notifyfs.c">
+      <Filter>Source</Filter>
+    </ClCompile>
+  </ItemGroup>
+</Project>

tst/winfsp-tests/posix-test.c

@@ -25,7 +25,7 @@
 
 #include "winfsp-tests.h"
 
-void posix_map_sid_test(void)
+static void posix_map_sid_test(void)
 {
     struct
     {
@@ -171,7 +171,7 @@ void posix_map_sid_test(void)
     LocalFree(map[sizeof map / sizeof map[0] - 1].SidStr);
 }
 
-void posix_map_sd_test(void)
+static void posix_map_sd_test(void)
 {
     struct
     {
@@ -237,7 +237,93 @@ void posix_map_sd_test(void)
     }
 }
 
-void posix_map_path_test(void)
+static void posix_merge_sd_test(void)
+{
+    struct
+    {
+        UINT32 Uid, Gid, Mode;
+        PWSTR ExistingSddl;
+        PWSTR Sddl;
+    } map[] =
+    {
+        {
+            18, 544, 00000,
+            0,
+            L"O:SYG:BAD:P(A;;0x1f0198;;;SY)(A;;0x120088;;;BA)(A;;0x120088;;;WD)"
+        },
+        {
+            18, 544, 00000,
+            L"",
+            L"O:SYG:BA"
+        },
+        {
+            18, 544, 00000,
+            L"O:WD",
+            L"O:WDG:BA"
+        },
+        {
+            18, 544, 00000,
+            L"G:WD",
+            L"O:SYG:WD"
+        },
+        {
+            18, 544, 00000,
+            L"O:WDG:WD",
+            L"O:WDG:WD"
+        },
+        {
+            18, 544, 00000,
+            L"D:P",
+            L"O:SYG:BAD:P"
+        },
+        {
+            18, 544, 00000,
+            L"D:P(A;;FA;;;SY)",
+            L"O:SYG:BAD:P(A;;FA;;;SY)"
+        },
+        {
+            18, 544, 00000,
+            L"O:WDG:WDD:P(A;;FA;;;SY)",
+            L"O:WDG:WDD:P(A;;FA;;;SY)"
+        },
+    };
+    NTSTATUS Result;
+    BOOL Success;
+    PSECURITY_DESCRIPTOR ExistingSecurityDescriptor, SecurityDescriptor;
+    PWSTR Sddl;
+
+    for (size_t i = 0; sizeof map / sizeof map[0] > i; i++)
+    {
+        if (0 != map[i].ExistingSddl)
+        {
+            Success = ConvertStringSecurityDescriptorToSecurityDescriptorW(
+                map[i].ExistingSddl, SDDL_REVISION_1,
+                &ExistingSecurityDescriptor, 0);
+            ASSERT(Success);
+        }
+        else
+            ExistingSecurityDescriptor = 0;
+
+        Result = FspPosixMergePermissionsToSecurityDescriptor(
+            map[i].Uid, map[i].Gid, map[i].Mode, ExistingSecurityDescriptor, &SecurityDescriptor);
+        ASSERT(NT_SUCCESS(Result));
+
+        Success = ConvertSecurityDescriptorToStringSecurityDescriptorW(
+            SecurityDescriptor, SDDL_REVISION_1,
+            OWNER_SECURITY_INFORMATION | GROUP_SECURITY_INFORMATION | DACL_SECURITY_INFORMATION,
+            &Sddl, 0);
+        ASSERT(Success);
+        ASSERT(0 == wcscmp(map[i].Sddl, Sddl));
+        LocalFree(Sddl);
+
+        FspDeleteSecurityDescriptor(SecurityDescriptor,
+            FspPosixMergePermissionsToSecurityDescriptor);
+
+        LocalFree(ExistingSecurityDescriptor);
+    }
+}
+
+static void posix_map_path_test(void)
 {
     struct
     {
@@ -274,5 +360,6 @@ void posix_tests(void)
 
     TEST(posix_map_sid_test);
     TEST(posix_map_sd_test);
+    TEST(posix_merge_sd_test);
     TEST(posix_map_path_test);
 }