[hbelusca] 57923: [WIN32K] Fix BSOD when starting ReactOS in Safe Mode : NEVER dereference a NULL pointer in a DPRINT or you are dead !! (here, the possible NULL pointer is GetW32ProcessInfo()->prp...

Author: hbelusca
Date: Sun Dec 16 14:01:32 2012
New Revision: 57923

URL: http://svn.reactos.org/svn/reactos?rev=57923&view=rev
Log:
[WIN32K]
Fix BSOD when starting ReactOS in Safe Mode :
NEVER dereference a NULL pointer in a DPRINT or you are dead !! (here, the possible NULL pointer is GetW32ProcessInfo()->prpwinsta).
More precisely, you obtain:

<NTOSKRNL.EXE:112296 (ReactOS/ntoskrnl/ke/i386/traphdlr.c:1246 (@KiTrap0EHandler@4))>
<NTOSKRNL.EXE:110154 (ReactOS/ntoskrnl/ke/i386/trap.s:0 (_KiTrap0E))>
<NTOSKRNL.EXE:142926 (ReactOS/lib/sdk/crt/printf/streamout.c:644 (streamout))>
<NTOSKRNL.EXE:140631 (ReactOS/lib/sdk/crt/printf/_sxprintf.c:61 (_vsnprintf))>
<NTOSKRNL.EXE:12736a (ReactOS/lib/rtl/debug.c:85 (vDbgPrintExWithPrefixInternal@24))>
<NTOSKRNL.EXE:12751c (ReactOS/lib/rtl/debug.c:209 (DbgPrint))>
<win32k.sys:55034 (ReactOS/win32ss/user/ntuser/sysparams.c:451 (SpiGet))>
<win32k.sys:56bc7 (ReactOS/win32ss/user/ntuser/sysparams.c:963 (@UserSystemParametersInfo@16)

Modified:
    trunk/reactos/win32ss/user/ntuser/sysparams.c

Modified: trunk/reactos/win32ss/user/ntuser/sysparams.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/win32ss/user/ntuser/syspara...
==============================================================================
--- trunk/reactos/win32ss/user/ntuser/sysparams.c [iso-8859-1] (original)
+++ trunk/reactos/win32ss/user/ntuser/sysparams.c [iso-8859-1] Sun Dec 16 14:01:32 2012
@@ -25,9 +25,18 @@
 #define METRIC2REG(met) (-((((met) * 1440)- 0) / dpi))

#define REQ_INTERACTIVE_WINSTA(err) \
-    if ( GetW32ProcessInfo()->prpwinsta != InputWindowStation) \
+    if (GetW32ProcessInfo()->prpwinsta) \
     { \
-        ERR("NtUserSystemParametersInfo requires interactive window station (current is %wZ)\n", &GetW32ProcessInfo()->prpwinsta->Name); \
+        if (GetW32ProcessInfo()->prpwinsta != InputWindowStation) \
+        { \
+            ERR("NtUserSystemParametersInfo requires interactive window station (current is %wZ)\n", &GetW32ProcessInfo()->prpwinsta->Name); \
+            EngSetLastError(err); \
+            return 0; \
+        } \
+    } \
+    else \
+    { \
+        ERR("NtUserSystemParametersInfo called without active window station, and it requires an interactive one.\n"); \
         EngSetLastError(err); \
         return 0; \
     }
@@ -1568,7 +1577,7 @@
     /* Get a pointer to the current Windowstation */
     if (!ppi->prpwinsta)
     {
-        ERR("UserSystemParametersInfo called without active windowstation.\n");
+        ERR("UserSystemParametersInfo called without active window station.\n");
         //ASSERT(FALSE);
         //return FALSE;
     }