11 files changed, 180 insertions, 65 deletions

diff --git a/src/burn/engine/approvedexe.h b/src/burn/engine/approvedexe.h
index cbfda601..7a68c174 100644
--- a/src/burn/engine/approvedexe.h
+++ b/src/burn/engine/approvedexe.h
@@ -6,15 +6,6 @@
 extern "C" {
 #endif
 
-// forward declare
-
-enum BURN_MODE;
-typedef struct _BOOTSTRAPPER_ENGINE_CONTEXT BOOTSTRAPPER_ENGINE_CONTEXT;
-typedef struct _BURN_CACHE BURN_CACHE;
-typedef struct _BURN_DEPENDENCIES BURN_DEPENDENCIES;
-typedef struct _BURN_ENGINE_COMMAND BURN_ENGINE_COMMAND;
-typedef struct  _BURN_LOGGING BURN_LOGGING;
-
 // structs
 
 typedef struct _BURN_APPROVED_EXE
diff --git a/src/burn/engine/core.h b/src/burn/engine/core.h
index 31f63ed4..c75d42de 100644
--- a/src/burn/engine/core.h
+++ b/src/burn/engine/core.h
@@ -38,7 +38,6 @@ const LPCWSTR BURN_COMMANDLINE_SWITCH_SPLASH_SCREEN = L"burn.splash.screen";
 const LPCWSTR BURN_COMMANDLINE_SWITCH_SYSTEM_COMPONENT = L"burn.system.component";
 const LPCWSTR BURN_COMMANDLINE_SWITCH_PREFIX = L"burn.";
 
-const LPCWSTR BURN_BUNDLE_LAYOUT_DIRECTORY = L"WixBundleLayoutDirectory";
 const LPCWSTR BURN_BUNDLE_ACTION = L"WixBundleAction";
 const LPCWSTR BURN_BUNDLE_ACTIVE_PARENT = L"WixBundleActiveParent";
 const LPCWSTR BURN_BUNDLE_COMMAND_LINE_ACTION = L"WixBundleCommandLineAction";
@@ -48,17 +47,17 @@ const LPCWSTR BURN_BUNDLE_FORCED_RESTART_PACKAGE = L"WixBundleForcedRestartPacka
 const LPCWSTR BURN_BUNDLE_INSTALLED = L"WixBundleInstalled";
 const LPCWSTR BURN_BUNDLE_ELEVATED = L"WixBundleElevated";
 const LPCWSTR BURN_BUNDLE_PROVIDER_KEY = L"WixBundleProviderKey";
-const LPCWSTR BURN_BUNDLE_MANUFACTURER = L"WixBundleManufacturer";
 const LPCWSTR BURN_BUNDLE_SOURCE_PROCESS_PATH = L"WixBundleSourceProcessPath";
 const LPCWSTR BURN_BUNDLE_SOURCE_PROCESS_FOLDER = L"WixBundleSourceProcessFolder";
 const LPCWSTR BURN_BUNDLE_TAG = L"WixBundleTag";
 const LPCWSTR BURN_BUNDLE_UILEVEL = L"WixBundleUILevel";
 const LPCWSTR BURN_BUNDLE_VERSION = L"WixBundleVersion";
-const LPCWSTR BURN_REBOOT_PENDING = L"RebootPending";
 
-// The following constants must stay in sync with src\api\wix\WixToolset.Data\Burn\BurnConstants.cs
+// The following well-known variables are settable by the BA.
+const LPCWSTR BURN_BUNDLE_LAYOUT_DIRECTORY = L"WixBundleLayoutDirectory";
 const LPCWSTR BURN_BUNDLE_NAME = L"WixBundleName";
 const LPCWSTR BURN_BUNDLE_INPROGRESS_NAME = L"WixBundleInProgressName";
+const LPCWSTR BURN_BUNDLE_MANUFACTURER = L"WixBundleManufacturer";
 const LPCWSTR BURN_BUNDLE_ORIGINAL_SOURCE = L"WixBundleOriginalSource";
 const LPCWSTR BURN_BUNDLE_ORIGINAL_SOURCE_FOLDER = L"WixBundleOriginalSourceFolder";
 const LPCWSTR BURN_BUNDLE_LAST_USED_SOURCE = L"WixBundleLastUsedSource";
diff --git a/src/burn/engine/logging.cpp b/src/burn/engine/logging.cpp
index 68f0c35b..ae056921 100644
--- a/src/burn/engine/logging.cpp
+++ b/src/burn/engine/logging.cpp
@@ -28,6 +28,37 @@ static HRESULT GetNonSessionSpecificTempFolder(
 
 // function definitions
 
+extern "C" HRESULT LoggingParseFromXml(
+    __in BURN_LOGGING* pLog,
+    __in IXMLDOMNode* pixnBundle
+    )
+{
+    HRESULT hr = S_OK;
+    IXMLDOMNode* pixnLog = NULL;
+    BOOL fXmlFound = FALSE;
+
+    // parse the log element, if present.
+    hr = XmlSelectSingleNode(pixnBundle, L"Log", &pixnLog);
+    ExitOnOptionalXmlQueryFailure(hr, fXmlFound, "Failed to get Log element.");
+
+    if (fXmlFound)
+    {
+        hr = XmlGetAttributeEx(pixnLog, L"PathVariable", &pLog->sczPathVariable);
+        ExitOnOptionalXmlQueryFailure(hr, fXmlFound, "Failed to get Log/@PathVariable.");
+
+        hr = XmlGetAttributeEx(pixnLog, L"Prefix", &pLog->sczPrefix);
+        ExitOnRequiredXmlQueryFailure(hr, "Failed to get Log/@Prefix attribute.");
+
+        hr = XmlGetAttributeEx(pixnLog, L"Extension", &pLog->sczExtension);
+        ExitOnRequiredXmlQueryFailure(hr, "Failed to get Log/@Extension attribute.");
+    }
+
+LExit:
+    ReleaseObject(pixnLog);
+
+    return hr;
+}
+
 extern "C" HRESULT LoggingOpen(
     __in BURN_LOGGING* pLog,
     __in BURN_ENGINE_COMMAND* pInternalCommand,
@@ -244,7 +275,6 @@ extern "C" HRESULT LoggingSetCompatiblePackageVariable(
     )
 {
     HRESULT hr = S_OK;
-    LPWSTR sczLogPathVariable = NULL;
     LPWSTR sczLogPath = NULL;
 
     // Make sure that no package log files are created when logging has been disabled via Log element.
@@ -253,16 +283,12 @@ extern "C" HRESULT LoggingSetCompatiblePackageVariable(
         ExitFunction();
     }
 
-    if (pPackage->sczLogPathVariable && *pPackage->sczLogPathVariable)
+    if (pPackage->sczCompatibleLogPathVariable && *pPackage->sczCompatibleLogPathVariable)
     {
-        // Format a suitable log path variable from the original package.
-        hr = StrAllocFormatted(&sczLogPathVariable, L"%ls_Compatible", pPackage->sczLogPathVariable);
-        ExitOnFailure(hr, "Failed to format log path variable for compatible package.");
-
         hr = StrAllocFormatted(&sczLogPath, L"%ls_%03u_%ls_%ls.%ls", pLog->sczPrefix, vdwPackageSequence, pPackage->sczId, pPackage->compatiblePackage.compatibleEntry.sczId, pLog->sczExtension);
         ExitOnFailure(hr, "Failed to allocate path for package log.");
 
-        hr = VariableSetString(pVariables, sczLogPathVariable, sczLogPath, FALSE, FALSE);
+        hr = VariableSetString(pVariables, pPackage->sczCompatibleLogPathVariable, sczLogPath, FALSE, FALSE);
         ExitOnFailure(hr, "Failed to set log path into variable.");
 
         if (psczLogPath)
@@ -273,7 +299,6 @@ extern "C" HRESULT LoggingSetCompatiblePackageVariable(
     }
 
 LExit:
-    ReleaseStr(sczLogPathVariable);
     ReleaseStr(sczLogPath);
 
     return hr;
diff --git a/src/burn/engine/logging.h b/src/burn/engine/logging.h
index 000b04f8..5597bb57 100644
--- a/src/burn/engine/logging.h
+++ b/src/burn/engine/logging.h
@@ -41,6 +41,10 @@ typedef struct _BURN_LOGGING
 
 // function declarations
 
+HRESULT LoggingParseFromXml(
+    __in BURN_LOGGING* pLog,
+    __in IXMLDOMNode* pixnBundle
+    );
 HRESULT LoggingOpen(
     __in BURN_LOGGING* pLog,
     __in BURN_ENGINE_COMMAND* pInternalCommand,
diff --git a/src/burn/engine/manifest.cpp b/src/burn/engine/manifest.cpp
index 0cd10dbb..c0d67c19 100644
--- a/src/burn/engine/manifest.cpp
+++ b/src/burn/engine/manifest.cpp
@@ -67,31 +67,14 @@ static HRESULT ParseFromXml(
 {
     HRESULT hr = S_OK;
     IXMLDOMElement* pixeBundle = NULL;
-    IXMLDOMNode* pixnLog = NULL;
     IXMLDOMNode* pixnChain = NULL;
 
     // get bundle element
     hr = pixdDocument->get_documentElement(&pixeBundle);
     ExitOnFailure(hr, "Failed to get bundle element.");
 
-    // parse the log element, if present.
-    hr = XmlSelectSingleNode(pixeBundle, L"Log", &pixnLog);
-    ExitOnFailure(hr, "Failed to get Log element.");
-
-    if (S_OK == hr)
-    {
-        hr = XmlGetAttributeEx(pixnLog, L"PathVariable", &pEngineState->log.sczPathVariable);
-        if (E_NOTFOUND != hr)
-        {
-            ExitOnFailure(hr, "Failed to get Log/@PathVariable.");
-        }
-
-        hr = XmlGetAttributeEx(pixnLog, L"Prefix", &pEngineState->log.sczPrefix);
-        ExitOnFailure(hr, "Failed to get Log/@Prefix attribute.");
-
-        hr = XmlGetAttributeEx(pixnLog, L"Extension", &pEngineState->log.sczExtension);
-        ExitOnFailure(hr, "Failed to get Log/@Extension attribute.");
-    }
+    hr = LoggingParseFromXml(&pEngineState->log, pixeBundle);
+    ExitOnFailure(hr, "Failed to parse logging.");
 
     // get the chain element
     hr = XmlSelectSingleNode(pixeBundle, L"Chain", &pixnChain);
@@ -167,7 +150,6 @@ static HRESULT ParseFromXml(
 
 LExit:
     ReleaseObject(pixnChain);
-    ReleaseObject(pixnLog);
     ReleaseObject(pixeBundle);
     return hr;
 }
diff --git a/src/burn/engine/package.cpp b/src/burn/engine/package.cpp
index c56f74c8..fe8af497 100644
--- a/src/burn/engine/package.cpp
+++ b/src/burn/engine/package.cpp
@@ -174,6 +174,13 @@ extern "C" HRESULT PackagesParseFromXml(
         hr = XmlGetAttributeEx(pixnNode, L"RollbackLogPathVariable", &pPackage->sczRollbackLogPathVariable);
         ExitOnOptionalXmlQueryFailure(hr, fFoundXml, "Failed to get @RollbackLogPathVariable.");
 
+        if (pPackage->sczLogPathVariable && *pPackage->sczLogPathVariable)
+        {
+            // Format a suitable log path variable from the original package.
+            hr = StrAllocFormatted(&pPackage->sczCompatibleLogPathVariable, L"%ls_Compatible", pPackage->sczLogPathVariable);
+            ExitOnFailure(hr, "Failed to format log path variable for compatible package.");
+        }
+
         // @InstallCondition
         hr = XmlGetAttributeEx(pixnNode, L"InstallCondition", &pPackage->sczInstallCondition);
         ExitOnOptionalXmlQueryFailure(hr, fFoundXml, "Failed to get @InstallCondition.");
@@ -365,6 +372,7 @@ extern "C" void PackageUninitialize(
     ReleaseStr(pPackage->sczId);
     ReleaseStr(pPackage->sczLogPathVariable);
     ReleaseStr(pPackage->sczRollbackLogPathVariable);
+    ReleaseStr(pPackage->sczCompatibleLogPathVariable);
     ReleaseStr(pPackage->sczInstallCondition);
     ReleaseStr(pPackage->sczRepairCondition);
     ReleaseStr(pPackage->sczCacheId);
diff --git a/src/burn/engine/package.h b/src/burn/engine/package.h
index e8d49e53..e45c775d 100644
--- a/src/burn/engine/package.h
+++ b/src/burn/engine/package.h
@@ -262,6 +262,7 @@ typedef struct _BURN_PACKAGE
 
     LPWSTR sczLogPathVariable;          // name of the variable that will be set to the log path.
     LPWSTR sczRollbackLogPathVariable;  // name of the variable that will be set to the rollback path.
+    LPWSTR sczCompatibleLogPathVariable;
 
     LPWSTR sczInstallCondition;
     LPWSTR sczRepairCondition;
diff --git a/src/burn/engine/platform.h b/src/burn/engine/platform.h
index 876b02c2..49d8f3e9 100644
--- a/src/burn/engine/platform.h
+++ b/src/burn/engine/platform.h
@@ -8,6 +8,16 @@
 extern "C" {
 #endif
 
+// forward declare
+
+enum BURN_MODE;
+typedef struct _BOOTSTRAPPER_ENGINE_CONTEXT BOOTSTRAPPER_ENGINE_CONTEXT;
+typedef struct _BURN_CACHE BURN_CACHE;
+typedef struct _BURN_DEPENDENCIES BURN_DEPENDENCIES;
+typedef struct _BURN_ENGINE_COMMAND BURN_ENGINE_COMMAND;
+typedef struct  _BURN_LOGGING BURN_LOGGING;
+typedef struct  _BURN_PACKAGES BURN_PACKAGES;
+
 
 // typedefs
 
diff --git a/src/burn/engine/registration.cpp b/src/burn/engine/registration.cpp
index d0e5c677..484c08ac 100644
--- a/src/burn/engine/registration.cpp
+++ b/src/burn/engine/registration.cpp
@@ -443,7 +443,7 @@ extern "C" HRESULT RegistrationSetDynamicVariables(
     hr = VariableSetNumeric(pVariables, BURN_BUNDLE_INSTALLED, llInstalled, TRUE);
     ExitOnFailure(hr, "Failed to set the bundle installed built-in variable.");
 
-    hr = VariableSetNumeric(pVariables, BURN_REBOOT_PENDING, IsWuRebootPending() || IsRegistryRebootPending(), TRUE);
+    hr = VariableSetNumeric(pVariables, VARIABLE_REBOOTPENDING, IsWuRebootPending() || IsRegistryRebootPending(), TRUE);
     ExitOnFailure(hr, "Failed to overwrite the bundle reboot-pending built-in variable.");
 
 LExit:
diff --git a/src/burn/engine/variable.cpp b/src/burn/engine/variable.cpp
index 8d208a66..81fa31b7 100644
--- a/src/burn/engine/variable.cpp
+++ b/src/burn/engine/variable.cpp
@@ -14,6 +14,12 @@ typedef const struct _BUILT_IN_VARIABLE_DECLARATION
     BOOL fOverridable;
 } BUILT_IN_VARIABLE_DECLARATION;
 
+typedef const struct _WELL_KNOWN_VARIABLE_DECLARATION
+{
+    LPCWSTR wzVariable;
+    BOOL fPersist;
+} WELL_KNOWN_VARIABLE_DECLARATION;
+
 
 // constants
 
@@ -71,6 +77,11 @@ static HRESULT AddBuiltInVariable(
     __in BOOL fPersist,
     __in BOOL fOverridable
     );
+static HRESULT AddWellKnownVariable(
+    __in BURN_VARIABLES* pVariables,
+    __in LPCWSTR wzVariable,
+    __in BOOL fPersisted
+    );
 static HRESULT GetVariable(
     __in BURN_VARIABLES* pVariables,
     __in_z LPCWSTR wzVariable,
@@ -81,6 +92,11 @@ static HRESULT FindVariableIndexByName(
     __in_z LPCWSTR wzVariable,
     __out DWORD* piVariable
     );
+static HRESULT InsertUserVariable(
+    __in BURN_VARIABLES* pVariables,
+    __in_z LPCWSTR wzVariable,
+    __in DWORD iPosition
+    );
 static HRESULT InsertVariable(
     __in BURN_VARIABLES* pVariables,
     __in_z LPCWSTR wzVariable,
@@ -248,7 +264,7 @@ extern "C" HRESULT VariableInitialize(
 #endif
         {L"ProgramFiles6432Folder", InitializeVariable6432Folder, CSIDL_PROGRAM_FILES},
         {L"ProgramMenuFolder", InitializeVariableCsidlFolder, CSIDL_PROGRAMS},
-        {L"RebootPending", InitializeVariableNumeric, 0},
+        {VARIABLE_REBOOTPENDING, InitializeVariableNumeric, 0},
         {L"SendToFolder", InitializeVariableCsidlFolder, CSIDL_SENDTO},
         {L"ServicePackLevel", InitializeVariableVersionNT, OS_INFO_VARIABLE_ServicePackLevel},
         {L"StartMenuFolder", InitializeVariableCsidlFolder, CSIDL_STARTMENU},
@@ -283,6 +299,17 @@ extern "C" HRESULT VariableInitialize(
         {BURN_BUNDLE_VERSION, InitializeVariableVersion, (DWORD_PTR)L"0", FALSE, TRUE},
     };
 
+    const WELL_KNOWN_VARIABLE_DECLARATION vrgWellKnownVariableNames[] =
+    {
+        { BURN_BUNDLE_LAYOUT_DIRECTORY },
+        { BURN_BUNDLE_NAME, TRUE },
+        { BURN_BUNDLE_INPROGRESS_NAME, TRUE },
+        { BURN_BUNDLE_LAST_USED_SOURCE, TRUE },
+        { BURN_BUNDLE_MANUFACTURER, TRUE },
+        { BURN_BUNDLE_ORIGINAL_SOURCE, TRUE },
+        { BURN_BUNDLE_ORIGINAL_SOURCE_FOLDER, TRUE },
+    };
+
     for (DWORD i = 0; i < countof(vrgBuiltInVariables); ++i)
     {
         BUILT_IN_VARIABLE_DECLARATION* pBuiltInVariable = &vrgBuiltInVariables[i];
@@ -291,6 +318,14 @@ extern "C" HRESULT VariableInitialize(
         ExitOnFailure(hr, "Failed to add built-in variable: %ls.", pBuiltInVariable->wzVariable);
     }
 
+    for (DWORD i = 0; i < countof(vrgWellKnownVariableNames); ++i)
+    {
+        WELL_KNOWN_VARIABLE_DECLARATION* pWellKnownVariable = &vrgWellKnownVariableNames[i];
+
+        hr = AddWellKnownVariable(pVariables, pWellKnownVariable->wzVariable, pWellKnownVariable->fPersist);
+        ExitOnFailure(hr, "Failed to add well-known variable: %ls.", pWellKnownVariable->wzVariable);
+    }
+
 LExit:
     return hr;
 }
@@ -301,6 +336,7 @@ extern "C" HRESULT VariablesParseFromXml(
     )
 {
     HRESULT hr = S_OK;
+    BOOL fXmlFound = FALSE;
     IXMLDOMNode* pixnCommandLine = NULL;
     IXMLDOMNodeList* pixnNodes = NULL;
     IXMLDOMNode* pixnNode = NULL;
@@ -315,17 +351,13 @@ extern "C" HRESULT VariablesParseFromXml(
 
     ::EnterCriticalSection(&pVariables->csAccess);
 
-    // select registration node
+    // select command-line node
     hr = XmlSelectSingleNode(pixnBundle, L"CommandLine", &pixnCommandLine);
-    if (S_FALSE == hr)
-    {
-        hr = E_NOTFOUND;
-    }
-    ExitOnFailure(hr, "Failed to select CommandLine node.");
+    ExitOnRequiredXmlQueryFailure(hr, "Failed to select CommandLine node.");
 
     // @Variables
     hr = XmlGetAttributeEx(pixnCommandLine, L"Variables", &scz);
-    ExitOnFailure(hr, "Failed to get CommandLine/@Variables.");
+    ExitOnRequiredXmlQueryFailure(hr, "Failed to get CommandLine/@Variables.");
 
     if (CSTR_EQUAL == ::CompareStringW(LOCALE_INVARIANT, 0, scz, -1, L"upperCase", -1))
     {
@@ -337,8 +369,7 @@ extern "C" HRESULT VariablesParseFromXml(
     }
     else
     {
-        hr = E_INVALIDARG;
-        ExitOnFailure(hr, "Invalid value for CommandLine/@Variables: %ls", scz);
+        ExitWithRootFailure(hr, E_INVALIDARG, "Invalid value for CommandLine/@Variables: %ls", scz);
     }
 
     // select variable nodes
@@ -357,28 +388,28 @@ extern "C" HRESULT VariablesParseFromXml(
 
         // @Id
         hr = XmlGetAttributeEx(pixnNode, L"Id", &sczId);
-        ExitOnFailure(hr, "Failed to get @Id.");
+        ExitOnRequiredXmlQueryFailure(hr, "Failed to get @Id.");
 
         // @Hidden
         hr = XmlGetYesNoAttribute(pixnNode, L"Hidden", &fHidden);
-        ExitOnFailure(hr, "Failed to get @Hidden.");
+        ExitOnRequiredXmlQueryFailure(hr, "Failed to get @Hidden.");
 
         // @Persisted
         hr = XmlGetYesNoAttribute(pixnNode, L"Persisted", &fPersisted);
-        ExitOnFailure(hr, "Failed to get @Persisted.");
+        ExitOnRequiredXmlQueryFailure(hr, "Failed to get @Persisted.");
 
         // @Value
         hr = XmlGetAttributeEx(pixnNode, L"Value", &scz);
-        if (E_NOTFOUND != hr)
-        {
-            ExitOnFailure(hr, "Failed to get @Value.");
+        ExitOnOptionalXmlQueryFailure(hr, fXmlFound, "Failed to get @Value.");
 
+        if (fXmlFound)
+        {
             hr = BVariantSetString(&value, scz, 0, FALSE);
             ExitOnFailure(hr, "Failed to set variant value.");
 
             // @Type
             hr = XmlGetAttributeEx(pixnNode, L"Type", &scz);
-            ExitOnFailure(hr, "Failed to get @Type.");
+            ExitOnRequiredXmlQueryFailure(hr, "Failed to get @Type.");
 
             if (CSTR_EQUAL == ::CompareStringW(LOCALE_INVARIANT, 0, scz, -1, L"formatted", -1))
             {
@@ -414,8 +445,7 @@ extern "C" HRESULT VariablesParseFromXml(
             }
             else
             {
-                hr = E_INVALIDARG;
-                ExitOnFailure(hr, "Invalid value for @Type: %ls", scz);
+                ExitWithRootFailure(hr, E_INVALIDARG, "Invalid value for @Type: %ls", scz);
             }
         }
         else
@@ -444,14 +474,18 @@ extern "C" HRESULT VariablesParseFromXml(
         // insert element if not found
         if (S_FALSE == hr)
         {
-            hr = InsertVariable(pVariables, sczId, iVariable);
+            hr = InsertUserVariable(pVariables, sczId, iVariable);
             ExitOnFailure(hr, "Failed to insert variable '%ls'.", sczId);
         }
         else if (BURN_VARIABLE_INTERNAL_TYPE_NORMAL < pVariables->rgVariables[iVariable].internalType)
         {
-            hr = E_INVALIDARG;
-            ExitOnRootFailure(hr, "Attempt to set built-in variable value: %ls", sczId);
+            ExitWithRootFailure(hr, E_INVALIDARG, "Attempt to add built-in variable: %ls", sczId);
         }
+        else
+        {
+            ExitWithRootFailure(hr, E_INVALIDARG, "Attempt to add variable again: %ls", sczId);
+        }
+
         pVariables->rgVariables[iVariable].fHidden = fHidden;
         pVariables->rgVariables[iVariable].fPersisted = fPersisted;
 
@@ -1409,8 +1443,12 @@ static HRESULT AddBuiltInVariable(
         hr = InsertVariable(pVariables, wzVariable, iVariable);
         ExitOnFailure(hr, "Failed to insert variable.");
     }
+    else
+    {
+        ExitWithRootFailure(hr, E_INVALIDSTATE, "Attempted to add built-in variable again: %ls", wzVariable);
+    }
 
-    // set variable values
+    // set variable details
     pVariable = &pVariables->rgVariables[iVariable];
     pVariable->fPersisted = fPersist;
     pVariable->internalType = fOverridable ? BURN_VARIABLE_INTERNAL_TYPE_OVERRIDABLE_BUILTIN : BURN_VARIABLE_INTERNAL_TYPE_BUILTIN;
@@ -1421,6 +1459,43 @@ LExit:
     return hr;
 }
 
+static HRESULT AddWellKnownVariable(
+    __in BURN_VARIABLES* pVariables,
+    __in LPCWSTR wzVariable,
+    __in BOOL fPersisted
+    )
+{
+    HRESULT hr = S_OK;
+    DWORD iVariable = 0;
+    BURN_VARIABLE* pVariable = NULL;
+
+    hr = FindVariableIndexByName(pVariables, wzVariable, &iVariable);
+    ExitOnFailure(hr, "Failed to find variable value.");
+
+    // insert element if not found
+    if (S_FALSE == hr)
+    {
+        hr = InsertVariable(pVariables, wzVariable, iVariable);
+        ExitOnFailure(hr, "Failed to insert variable.");
+    }
+    else if (BURN_VARIABLE_INTERNAL_TYPE_NORMAL != pVariables->rgVariables[iVariable].internalType)
+    {
+        ExitWithRootFailure(hr, E_INVALIDSTATE, "Attempted to add built-in variable as a well-known variable: %ls", wzVariable);
+    }
+    else
+    {
+        ExitWithRootFailure(hr, E_INVALIDSTATE, "Attempted to add well-known variable again: %ls", wzVariable);
+    }
+
+    // set variable details
+    pVariable = &pVariables->rgVariables[iVariable];
+    pVariable->fPersisted = fPersisted;
+    pVariable->internalType = BURN_VARIABLE_INTERNAL_TYPE_NORMAL;
+
+LExit:
+    return hr;
+}
+
 static HRESULT GetVariable(
     __in BURN_VARIABLES* pVariables,
     __in_z LPCWSTR wzVariable,
@@ -1497,6 +1572,25 @@ LExit:
     return hr;
 }
 
+static HRESULT InsertUserVariable(
+    __in BURN_VARIABLES* pVariables,
+    __in_z LPCWSTR wzVariable,
+    __in DWORD iPosition
+    )
+{
+    HRESULT hr = S_OK;
+
+    if (CSTR_EQUAL == ::CompareStringW(LOCALE_INVARIANT, 0, wzVariable, 3, L"Wix", 3))
+    {
+            ExitWithRootFailure(hr, E_INVALIDARG, "Attempted to insert variable with reserved prefix: %ls", wzVariable);
+    }
+
+    hr = InsertVariable(pVariables, wzVariable, iPosition);
+
+LExit:
+    return hr;
+}
+
 static HRESULT InsertVariable(
     __in BURN_VARIABLES* pVariables,
     __in_z LPCWSTR wzVariable,
diff --git a/src/burn/engine/variable.h b/src/burn/engine/variable.h
index 9ed86ca7..f8d3e1e2 100644
--- a/src/burn/engine/variable.h
+++ b/src/burn/engine/variable.h
@@ -13,6 +13,7 @@ const LPCWSTR VARIABLE_DATE = L"Date";
 const LPCWSTR VARIABLE_LOGONUSER = L"LogonUser";
 const LPCWSTR VARIABLE_INSTALLERNAME = L"InstallerName";
 const LPCWSTR VARIABLE_INSTALLERVERSION = L"InstallerVersion";
+const LPCWSTR VARIABLE_REBOOTPENDING = L"RebootPending";
 
 
 // typedefs