[reactos] 04/04: [IMM32] ValidateHwndNoErr(): Apply ReactOS-specific handle table array fixup. (#3937) CORE-17741

[Hermès Bélusca-Maïto]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=0233bb72b30c12ed7ebb02...

commit 0233bb72b30c12ed7ebb02c4a1a4f45164d309e8
Author:     Hermès Bélusca-Maïto [e-mail]
AuthorDate: Tue Sep 7 22:05:54 2021 +0200
Commit:     Hermès Bélusca-Maïto [e-mail]
CommitDate: Thu Sep 9 16:15:13 2021 +0200

[IMM32] ValidateHwndNoErr(): Apply ReactOS-specific handle table array fixup. (#3937)
    CORE-17741

This function (which should belong to the user32 helpers) depends on the
    internal format of the USER handles table, that is ReactOS-specific. Its
    pointer value is stored in the win32k/user32 shared info section, and
    thus cannot be converted to user-space and stored back into that section.
    Therefore it needs to be retrieved and manually converted when the function
    is called.
---
 dll/win32/imm32/imm.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/dll/win32/imm32/imm.c b/dll/win32/imm32/imm.c
index 9f32bcc5d5d..1dc41f8e362 100644
--- a/dll/win32/imm32/imm.c
+++ b/dll/win32/imm32/imm.c
@@ -66,6 +66,7 @@ static PWND FASTCALL ValidateHwndNoErr(HWND hwnd)
     PCLIENTINFO ClientInfo = GetWin32ClientInfo();
     INT index;
     PUSER_HANDLE_TABLE ht;
+    PUSER_HANDLE_ENTRY he;
     WORD generation;

/* See if the window is cached */
@@ -76,15 +77,20 @@ static PWND FASTCALL ValidateHwndNoErr(HWND hwnd)
         return NULL;

ht = g_SharedInfo.aheList; /* handle table */
+    ASSERT(ht);
+    /* ReactOS-Specific! */
+    ASSERT(g_SharedInfo.ulSharedDelta != 0);
+    he = (PUSER_HANDLE_ENTRY)((ULONG_PTR)ht->handles - g_SharedInfo.ulSharedDelta);
+
     index = (LOWORD(hwnd) - FIRST_USER_HANDLE) >> 1;
-    if (index < 0 || index >= ht->nb_handles || ht->handles[index].type != TYPE_WINDOW)
+    if (index < 0 || index >= ht->nb_handles || he[index].type != TYPE_WINDOW)
         return NULL;

generation = HIWORD(hwnd);
-    if (generation != ht->handles[index].generation && generation && generation != 0xFFFF)
+    if (generation != he[index].generation && generation && generation != 0xFFFF)
         return NULL;

-    return (PWND)&ht->handles[index];
+    return (PWND)&he[index];
 }

static BOOL APIENTRY Imm32InitInstance(HMODULE hMod)