Question

If I try to create an environment block from within a 32 bit process (on a 64 bit OS) using CreateEnvironmentBlock() the environment block I get seems to be mostly correct but it has a few differences from one that gets created automatically by CreateProcess. Most notably PROCESSOR_ARCHITECTURE is usually x86 on 32 bit processes but the one from CreateEnvironmentBlock is amd64.

BOOL bResult = FALSE;
LPWSTR wszEnvBlock = NULL;
HANDLE tokenHandle;

OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &tokenHandle);

bResult = ::CreateEnvironmentBlock((LPVOID*)&wszEnvBlock, tokenHandle, TRUE);

LPWSTR wszCurrentItem = wszEnvBlock;
LPWSTR wszEqualsSign = NULL;
LPWSTR wszCurrentItemInuse = NULL;

ATL::CStringW wstrCurrentName;
ATL::CStringW wstrCurrentValue;

while (L'\0' != *wszCurrentItem)
{
    // Find the equals and temporarily set it to NULL
    wszCurrentItemInuse = wszCurrentItem;
    wszEqualsSign = wcschr(wszCurrentItem, L'=');
    *wszEqualsSign = L'\0';

    // Copy the Name and then set the equals back as it was
    wstrCurrentName = wszCurrentItem;
    *wszEqualsSign = L'=';

    // Move the current item to the next character after the equals sign,
    // Then copy the Value
    wszCurrentItem = ++wszEqualsSign;
    wstrCurrentValue = wszCurrentItem;

    // Move the current item to the next character after the terminating NULL character.
    wszCurrentItem = wcschr(wszCurrentItem, L'\0');
    wszCurrentItem++;

    // Insert the two read strings into the map
    wprintf(L"%s:%s\n", wstrCurrentName, wstrCurrentValue);
}

bResult = DestroyEnvironmentBlock((LPVOID)wszEnvBlock);

Produces the following output:

ADMSOURCE:\ddwds02\platform8\DesktopPersonalisation\Win7\GO\Source\adm
ALLUSERSPROFILE:C:\ProgramData APPDATA:C:\Users\bens\AppData\Roaming
asl.log:Destination=file AS_WDK6_DIR:C:\WinDDK\6000
AS_WDK7_DIR:C:\WinDDK\7600.16385.0 CLASSPATH:.;C:\Program Files
(x86)\Java\jre6\lib\ext\QTJava.zip CommonProgramFiles:C:\Program Files
(x86)\Common Files CommonProgramFiles(x86):C:\Program Files
(x86)\Common Files CommonProgramW6432:C:\Program Files\Common Files
COMPUTERNAME:APWADEV03 ComSpec:C:\Windows\system32\cmd.exe
CYGWIN:nodosfilewarning DEFAULT_CA_NR:CA100 DEVELOPMENT:c:\development
DEVLIBS:C:\development\libs FP_NO_HOST_CHECK:NO HOME:c:\users\bens
HOMEDRIVE:C: HOMEPATH:\Users\bens INCLUDE:C:\Program Files
(x86)\Microsoft Visual Studio .NET 2003\SDK\v1.1\includ e\
LIB:C:\Program Files (x86)\Microsoft Visual Studio .NET
2003\SDK\v1.1\Lib\ LOCALAPPDATA:C:\Users\bens\AppData\Local
LOCALHOMESHARE:C:\Users\bens LOGONSERVER:\APWADC01
NUMBER_OF_PROCESSORS:2 OS:Windows_NT
PATHEXT:.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC
PROCESSOR_ARCHITECTURE:AMD64 PROCESSOR_ARCHITEW6432:AMD64
PROCESSOR_IDENTIFIER:Intel64 Family 6 Model 23 Stepping 10,
GenuineIntel PROCESSOR_LEVEL:6 PROCESSOR_REVISION:170a
ProgramData:C:\ProgramData ProgramFiles:C:\Program Files (x86)
ProgramFiles(x86):C:\Program Files (x86) ProgramW6432:C:\Program Files
PSModulePath:C:\Windows\system32\WindowsPowerShell\v1.0\Modules\
PUBLIC:C:\Users\Public PVC_DDK_DIR:C:\WinDDK\6000 QTJAVA:C:\Program
Files (x86)\Java\jre6\lib\ext\QTJava.zip SESSIONNAME:Console
SP2C_ROOT:C:\Development\SP2C_Win7 SystemDrive:C:
SystemRoot:C:\Windows TEMP:C:\Users\bens\AppData\Local\Temp
TMP:C:\Users\bens\AppData\Local\Temp USERPROFILE:C:\Users\bens
VisualStudioDir:C:\Users\bens\Documents\Visual Studio 2010
VS100COMNTOOLS:C:\Program Files (x86)\Microsoft Visual Studio
10.0\Common7\Tools \ VS71COMNTOOLS:C:\Program Files (x86)\Microsoft
Visual Studio .NET 2003\Common7\T ools\ VS80COMNTOOLS:C:\Program Files
(x86)\Microsoft Visual Studio 8\Common7\Tools\
VS90COMNTOOLS:c:\Program Files (x86)\Microsoft Visual Studio
9.0\Common7\Tools\ windir:C:\Windows WIX:C:\Program Files
(x86)\Windows Installer XML v3\ WTTBIN:C:\Program Files\Microsoft
Driver Test Manager\Controller\
_NT_SYMBOL_PATH:srv*c:\
websymbols*http://msdl.microsoft.com/download/symbols;sr v*c:\pdbs
PATH:C:\Perl\site\bin;C:\Perl\bin;C:\Windows\system32;C:\Windows;C:\Windows\Syst
em32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files
(x86)\GTK 2-Runtime\bin;C:\Program Files\Broadcom\Broadcom
802.11\Driver;C:\Program Files\ Microsoft Driver Test
Manager\Controller\;C:\Program Files (x86)\FogBugz\FogBugz Command
Line Client;C:\Program Files (x86)\Microsoft SQL
Server\100\Tools\Binn\ ;C:\Program Files\Microsoft SQL
Server\100\Tools\Binn\;C:\Program Files\Microsof t SQL
Server\100\DTS\Binn\;C:\Program Files (x86)\Microsoft SQL
Server\100\Tools \Binn\VSShell\Common7\IDE\;C:\Program Files
(x86)\Microsoft SQL Server\100\DTS\B inn\;C:\Program
Files\TortoiseSVN\bin;C:\Program Files\SlikSvn\bin\;C:\cygwinx\b
in;C:\Program Files\Microsoft Windows Performance Toolkit\;C:\Program
Files (x86 )\Common Files\Teleca Shared;C:\Program Files
(x86)\QuickTime\QTSystem\;C:\Progr am Files
(x86)\AMD\CodeAnalyst\bin;C:\Program Files
(x86)\Nmap;c:\Users\bens\scr ipts\win;C:\Program Files (x86)\Microsoft
Visual Studio 10.0\;C:\Program Files ( x86)\Microsoft Visual Studio
10.0\VC\bin;

So is CreateEnvironmentBlock just broken on wow64? Also, the system environment seems to be defined in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment

How come there’s no wow64 equivalent of this?

Answer 1

This is a bug with CreateEnvironmentBlock(), MS are aware of the issue and have promised to fix it in some unspecified future release.