dll: FspFileSystemPreflight

build/VStudio/winfsp_sys.vcxproj.filters

@@ -113,8 +113,8 @@
     </ResourceCompile>
   </ItemGroup>
   <ItemGroup>
-    <None Include="..\..\src\sys\driver.inf.in">
+    <CustomBuild Include="..\..\src\sys\driver.inf.in">
       <Filter>Source</Filter>
-    </None>
+    </CustomBuild>
   </ItemGroup>
 </Project>

inc/winfsp/winfsp.h

@@ -845,6 +845,20 @@ typedef struct _FSP_FILE_SYSTEM_OPERATION_CONTEXT
     FSP_FSCTL_TRANSACT_REQ *Request;
     FSP_FSCTL_TRANSACT_RSP *Response;
 } FSP_FILE_SYSTEM_OPERATION_CONTEXT;
+/**
+ * Check whether creating a file system object is possible.
+ *
+ * @param DevicePath
+ *     The name of the control device for this file system. This must be either
+ *     FSP_FSCTL_DISK_DEVICE_NAME or FSP_FSCTL_NET_DEVICE_NAME.
+ * @param MountPoint
+ *     The mount point for the new file system. A value of NULL means that the file system should
+ *     use the next available drive letter counting downwards from Z: as its mount point.
+ * @return
+ *     STATUS_SUCCESS or error code.
+ */
+FSP_API NTSTATUS FspFileSystemPreflight(PWSTR DevicePath,
+    PWSTR MountPoint);
 /**
  * Create a file system object.
  *

src/dll/fs.c

@@ -72,6 +72,43 @@ VOID FspFileSystemFinalize(BOOLEAN Dynamic)
         TlsFree(FspFileSystemTlsKey);
 }
 
+FSP_API NTSTATUS FspFileSystemPreflight(PWSTR DevicePath,
+    PWSTR MountPoint)
+{
+    NTSTATUS Result;
+    WCHAR TargetPath[MAX_PATH];
+    HANDLE DirHandle;
+
+    Result = FspFsctlPreflight(DevicePath);
+    if (!NT_SUCCESS(Result))
+        return Result;
+
+    if (0 == MountPoint)
+        Result = STATUS_SUCCESS;
+    else
+    {
+        if (FspPathIsDrive(MountPoint))
+            Result = QueryDosDeviceW(MountPoint, TargetPath, MAX_PATH) ?
+                STATUS_OBJECT_NAME_COLLISION : STATUS_SUCCESS;
+        else
+        {
+            DirHandle = CreateFileW(MountPoint,
+                FILE_READ_ATTRIBUTES,
+                FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                0,
+                OPEN_EXISTING,
+                FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT,
+                0);
+            Result = INVALID_HANDLE_VALUE != DirHandle || ERROR_FILE_NOT_FOUND != GetLastError() ?
+                STATUS_OBJECT_NAME_COLLISION : STATUS_SUCCESS;
+            if (INVALID_HANDLE_VALUE != DirHandle)
+                CloseHandle(DirHandle);
+        }
+    }
+
+    return Result;
+}
+
 FSP_API NTSTATUS FspFileSystemCreate(PWSTR DevicePath,
     const FSP_FSCTL_VOLUME_PARAMS *VolumeParams,
     const FSP_FILE_SYSTEM_INTERFACE *Interface,

src/dll/fuse/fuse.c

@@ -230,36 +230,6 @@ FSP_FUSE_API int fsp_fuse_is_lib_option(struct fsp_fuse_env *env,
 
 static void fsp_fuse_cleanup(struct fuse *f);
 
-static NTSTATUS fsp_fuse_preflight(struct fuse *f)
-{
-    NTSTATUS Result;
-
-    Result = FspFsctlPreflight(f->VolumeParams.Prefix[0] ?
-        L"" FSP_FSCTL_NET_DEVICE_NAME : L"" FSP_FSCTL_DISK_DEVICE_NAME);
-    if (!NT_SUCCESS(Result))
-        return Result;
-
-    if (L'\0' != f->MountPoint)
-    {
-        if ((
-                (L'A' <= f->MountPoint[0] && f->MountPoint[0] <= L'Z') ||
-                (L'a' <= f->MountPoint[0] && f->MountPoint[0] <= L'z')
-            ) &&
-            L':' == f->MountPoint[1] || L'\0' == f->MountPoint[2])
-        {
-            if (GetLogicalDrives() & (1 << ((f->MountPoint[0] & ~0x20) - 'a')))
-                return STATUS_OBJECT_NAME_COLLISION;
-        }
-        else
-        if (L'*' == f->MountPoint[0] && L'\0' == f->MountPoint[1])
-            ;
-        else
-            return STATUS_OBJECT_NAME_INVALID;
-    }
-
-    return STATUS_SUCCESS;
-}
-
 static NTSTATUS fsp_fuse_svcstart(FSP_SERVICE *Service, ULONG argc, PWSTR *argv)
 {
     struct fuse *f = Service->UserContext;
@@ -380,7 +350,7 @@ static NTSTATUS fsp_fuse_svcstart(FSP_SERVICE *Service, ULONG argc, PWSTR *argv)
     FspFileSystemSetOperationGuardStrategy(f->FileSystem, f->OpGuardStrategy);
     FspFileSystemSetDebugLog(f->FileSystem, f->DebugLog);
 
-    if (L'\0' != f->MountPoint)
+    if (0 != f->MountPoint)
     {
         Result = FspFileSystemSetMountPoint(f->FileSystem,
             L'*' == f->MountPoint[0] && L'\0' == f->MountPoint[1] ? 0 : f->MountPoint);
@@ -548,7 +518,9 @@ FSP_FUSE_API struct fuse *fsp_fuse_new(struct fsp_fuse_env *env,
         goto fail;
     memcpy(f->MountPoint, ch->MountPoint, Size);
 
-    Result = fsp_fuse_preflight(f);
+    Result = FspFileSystemPreflight(
+        f->VolumeParams.Prefix[0] ? L"" FSP_FSCTL_NET_DEVICE_NAME : L"" FSP_FSCTL_DISK_DEVICE_NAME,
+        '*' != f->MountPoint[0] || '\0' != f->MountPoint[1] ? f->MountPoint : 0);
     if (!NT_SUCCESS(Result))
     {
         switch (Result)

tst/winfsp-tests/mount-test.c

@@ -272,6 +272,68 @@ void mount_volume_transact_test(void)
         mount_volume_transact_dotest(L"WinFsp.Net", L"\\\\winfsp-tests\\share");
 }
 
+void mount_preflight_dotest(PWSTR DeviceName)
+{
+    NTSTATUS Result;
+    WCHAR MountPoint[MAX_PATH];
+    WCHAR DirBuf[MAX_PATH];
+    DWORD Drives;
+    WCHAR Drive;
+    BOOL Success;
+
+    MountPoint[0] = L'C';
+    MountPoint[1] = L':';
+    MountPoint[2] = L'\0';
+
+    GetTestDirectory(DirBuf);
+
+    Drives = GetLogicalDrives();
+    ASSERT(0 != Drives);
+
+    Result = FspFileSystemPreflight(DeviceName, 0);
+    ASSERT(STATUS_SUCCESS == Result);
+
+    for (Drive = 'Z'; 'A' <= Drive; Drive--)
+        if (0 == (Drives & (1 << (Drive - 'A'))))
+            break;
+    ASSERT('A' <= Drive);
+
+    MountPoint[0] = Drive;
+    Result = FspFileSystemPreflight(DeviceName, MountPoint);
+    ASSERT(STATUS_SUCCESS == Result);
+
+    for (Drive = 'Z'; 'A' <= Drive; Drive--)
+        if (0 != (Drives & (1 << (Drive - 'A'))))
+            break;
+    ASSERT('A' <= Drive);
+
+    MountPoint[0] = Drive;
+    Result = FspFileSystemPreflight(DeviceName, MountPoint);
+    ASSERT(STATUS_OBJECT_NAME_COLLISION == Result);
+
+    StringCbPrintfW(MountPoint, sizeof MountPoint, L"%s\\dir1", DirBuf);
+
+    Result = FspFileSystemPreflight(DeviceName, MountPoint);
+    ASSERT(STATUS_SUCCESS == Result);
+
+    Success = CreateDirectoryW(MountPoint, 0);
+    ASSERT(Success);
+
+    Result = FspFileSystemPreflight(DeviceName, MountPoint);
+    ASSERT(STATUS_OBJECT_NAME_COLLISION == Result);
+
+    Success = RemoveDirectoryW(MountPoint);
+    ASSERT(Success);
+}
+
+void mount_preflight_test(void)
+{
+    if (WinFspDiskTests)
+        mount_preflight_dotest(L"WinFsp.Disk");
+    if (WinFspNetTests)
+        mount_preflight_dotest(L"WinFsp.Net");
+}
+
 void mount_tests(void)
 {
     if (NtfsTests || OptOplock)
@@ -282,4 +344,5 @@ void mount_tests(void)
     TEST_OPT(mount_create_volume_test);
     TEST_OPT(mount_volume_cancel_test);
     TEST_OPT(mount_volume_transact_test);
+    TEST_OPT(mount_preflight_test);
 }