[PATCH] kernel32: Add forward slash path handling to GetVolumePathNameW.

[Mark White]

From: Mark White

Fixes https://bugs.winehq.org/show_bug.cgi?id=42446

GetVolumePathNameW is causing some incompatibity problems with some Windows
applications such as Native Instruments "Native Access" because of an
inability to handle path names containing forward slash's whereas the
Windows GetVolumePathName's behaviour handles path names with both
forward and back slash's.

Tested on Debian Stretch and Windows Vista

Signed-off-by: Mark White 
---
 dlls/kernel32/tests/volume.c | 4 ++++
 dlls/kernel32/volume.c       | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/dlls/kernel32/tests/volume.c b/dlls/kernel32/tests/volume.c
index 365e38c444..c47043d288 100644
--- a/dlls/kernel32/tests/volume.c
+++ b/dlls/kernel32/tests/volume.c
@@ -772,6 +772,10 @@ static void test_GetVolumePathNameA(void)
             "s:omefile", "S:\" /* win2k, winxp */, sizeof(volume_path),
             ERROR_FILE_NOT_FOUND, NO_ERROR
         },
+        { /* test 42: a reasonable forward slash path that is guaranteed to exist */
+            "C:/windows/system32", "C:\", sizeof(volume_path),
+            NO_ERROR, NO_ERROR
+        },
     };
     BOOL ret, success;
     DWORD error;
diff --git a/dlls/kernel32/volume.c b/dlls/kernel32/volume.c
index b4163f02eb..ac887b2f3f 100644
--- a/dlls/kernel32/volume.c
+++ b/dlls/kernel32/volume.c
@@ -1670,6 +1670,7 @@ BOOL WINAPI GetVolumePathNameW(LPCWSTR filename, LPWSTR volumepathname, DWORD bu
     WCHAR fallbackpathW[] = { 'C',':','\',0 };
     NTSTATUS status = STATUS_SUCCESS;
     WCHAR *volumenameW = NULL, *c;
+    WCHAR *fwdslash;
     int pos, last_pos, stop_pos;
     UNICODE_STRING nt_name;
     ANSI_STRING unix_name;
@@ -1693,6 +1694,8 @@ BOOL WINAPI GetVolumePathNameW(LPCWSTR filename, LPWSTR volumepathname, DWORD bu
         return FALSE;
     }
     strcpyW( volumenameW, filename );
+    /* forward slash backslash replace */
+    for (fwdslash = volumenameW; *fwdslash; fwdslash++) if (*fwdslash == '/') *fwdslash = '\';
     stop_pos = 0;
     /* stop searching slashes early for NT-type and nearly NT-type paths */
     if (strncmpW(ntprefixW, filename, strlenW(ntprefixW)) == 0)