wine-staging/patches/ntdll-WRITECOPY/0005-ntdll-Only-enable-true-WRITECOPY-protection-when-a-s.patch

From 41b7ce7f165e3e3c02e1aa6067f66feeef41d234 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michael=20M=C3=BCller?= <michael@fds-team.de>
Date: Sat, 4 Oct 2014 03:22:09 +0200
Subject: ntdll: Only enable true WRITECOPY protection when a special
 environment variable is set.

---
 dlls/ntdll/virtual.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/dlls/ntdll/virtual.c b/dlls/ntdll/virtual.c
index 47654f4..6fad8f7 100644
--- a/dlls/ntdll/virtual.c
+++ b/dlls/ntdll/virtual.c
@@ -166,6 +166,21 @@ static const char *VIRTUAL_GetProtStr( BYTE prot )
     return buffer;
 }
 
+/* This might look like a hack, but it actually isn't - the 'experimental' version
+ * is correct, but it already has revealed a couple of additional Wine bugs, which
+ * were not triggered before, and there are probably some more.
+ * To avoid breaking Wine for everyone, the new correct implementation has to be
+ * manually enabled, until it is tested a bit more. */
+static inline BOOL experimental_WRITECOPY( void )
+{
+    static int enabled = -1;
+    if (enabled == -1)
+    {
+        const char *str = getenv("COMPHOLIO_WRITECOPY");
+        enabled = str && (atoi(str) != 0);
+    }
+    return enabled;
+}
 
 /***********************************************************************
  *           VIRTUAL_GetUnixProt
@@ -181,7 +196,13 @@ static int VIRTUAL_GetUnixProt( BYTE vprot )
         if (vprot & VPROT_WRITE) prot |= PROT_WRITE | PROT_READ;
         if (vprot & VPROT_EXEC) prot |= PROT_EXEC | PROT_READ;
 #if defined(__i386__)
-        if (vprot & VPROT_WRITECOPY) prot &= ~PROT_WRITE;
+        if (vprot & VPROT_WRITECOPY)
+        {
+            if (experimental_WRITECOPY())
+                prot &= ~PROT_WRITE;
+            else
+                prot |= PROT_WRITE | PROT_READ;
+        }
 #else
         /* FIXME: Architecture needs implementation of signal_init_early. */
         if (vprot & VPROT_WRITECOPY) prot |= PROT_WRITE | PROT_READ;
-- 
2.1.1