[PATCH 2/2] cmd: Implement mklink /j.

[Elizabeth Figura]

From: Elizabeth Figura

---
 programs/cmd/builtins.c | 62 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

diff --git a/programs/cmd/builtins.c b/programs/cmd/builtins.c
index aebd1136563..7bbf34df1ec 100644
--- a/programs/cmd/builtins.c
+++ b/programs/cmd/builtins.c
@@ -30,6 +30,10 @@

#include "wcmd.h"
 #include <shellapi.h>
+#define WIN32_NO_STATUS
+#include "winternl.h"
+#include "winioctl.h"
+#include "ddk/ntifs.h"
 #include "wine/debug.h"

WINE_DEFAULT_DEBUG_CHANNEL(cmd);
@@ -3961,6 +3965,62 @@ RETURN_CODE WCMD_color(void)
   return errorlevel = return_code;
 }

+/* We cannot use SetVolumeMountPoint(), because that function forbids setting
+ * arbitrary directories as mount points, whereas mklink /j allows it. */
+BOOL create_mount_point(const WCHAR *link, const WCHAR *target) {
+    UNICODE_STRING nt_link, nt_target;
+    REPARSE_DATA_BUFFER *data;
+    OBJECT_ATTRIBUTES attr;
+    IO_STATUS_BLOCK io;
+    unsigned int size;
+    NTSTATUS status;
+    HANDLE file;
+
+    TRACE( "link %s, target %s\n", debugstr_w(link), debugstr_w(target) );
+
+    status = RtlDosPathNameToNtPathName_U_WithStatus( link, &nt_link, NULL, NULL );
+    if (status) return FALSE;
+
+    status = RtlDosPathNameToNtPathName_U_WithStatus( target, &nt_target, NULL, NULL );
+    if (status)
+    {
+        RtlFreeUnicodeString( &nt_link );
+        return FALSE;
+    }
+
+    size = offsetof( REPARSE_DATA_BUFFER, MountPointReparseBuffer.PathBuffer );
+    size += (nt_target.Length + sizeof(WCHAR)) * 2;
+    data = malloc( size );
+
+    data->ReparseTag = IO_REPARSE_TAG_MOUNT_POINT;
+    data->ReparseDataLength = size - offsetof( REPARSE_DATA_BUFFER, MountPointReparseBuffer );
+    data->Reserved = 0;
+    data->MountPointReparseBuffer.SubstituteNameOffset = 0;
+    data->MountPointReparseBuffer.SubstituteNameLength = nt_target.Length;
+    data->MountPointReparseBuffer.PrintNameOffset = nt_target.Length + sizeof(WCHAR);
+    data->MountPointReparseBuffer.PrintNameLength = nt_target.Length;
+    memcpy( data->MountPointReparseBuffer.PathBuffer,
+            nt_target.Buffer, nt_target.Length + sizeof(WCHAR) );
+    memcpy( data->MountPointReparseBuffer.PathBuffer + (nt_target.Length / sizeof(WCHAR)) + 1,
+            nt_target.Buffer, nt_target.Length + sizeof(WCHAR) );
+    RtlFreeUnicodeString( &nt_target );
+
+    InitializeObjectAttributes( &attr, &nt_link, OBJ_CASE_INSENSITIVE, 0, NULL );
+    status = NtCreateFile( &file, GENERIC_WRITE, &attr, &io, NULL, 0, 0, FILE_OPEN_IF,
+                           FILE_OPEN_REPARSE_POINT | FILE_DIRECTORY_FILE, NULL, 0 );
+    RtlFreeUnicodeString( &nt_link );
+    if (status)
+    {
+        free( data );
+        return FALSE;
+    }
+
+    status = NtDeviceIoControlFile( file, NULL, NULL, NULL, &io, FSCTL_SET_REPARSE_POINT, data, size, NULL, 0 );
+    free( data );
+    NtClose( file );
+    return !status;
+}
+
 /****************************************************************************
  * WCMD_mklink
  */
@@ -4011,7 +4071,7 @@ RETURN_CODE WCMD_mklink(WCHAR *args)
         else if(!junction)
             ret = CreateSymbolicLinkW(file1, file2, isdir);
         else
-            TRACE("Junction links currently not supported.\n");
+            ret = create_mount_point(file1, file2);
     }

if (ret) return errorlevel = NO_ERROR;