private static object GetExpressionValue(ExpressionAst expressionAst, System.Management.Automation.ExecutionContext context, SessionStateInternal sessionStateInternal, IList usingValues, ref Func<FunctionContext, object> lambda, ref IScriptExtent[] sequencePoints, ref Type localsTupleType)
{
object obj2;
object obj4;
if (IsConstantValueVisitor.IsConstant(expressionAst, out obj2, false, false))
{
return obj2;
}
VariableExpressionAst varAst = expressionAst as VariableExpressionAst;
if (varAst != null)
{
return VariableOps.GetVariableValue(varAst.VariablePath, context, varAst);
}
if (lambda == null)
{
lambda = new Compiler().CompileSingleExpression(expressionAst, out sequencePoints, out localsTupleType);
}
SessionStateInternal engineSessionState = context.EngineSessionState;
try
{
if ((sessionStateInternal != null) && (context.EngineSessionState != sessionStateInternal))
{
context.EngineSessionState = sessionStateInternal;
}
ArrayList resultList = new ArrayList();
Pipe pipe = new Pipe(resultList);
try
{
FunctionContext arg = new FunctionContext {
_sequencePoints = sequencePoints,
_executionContext = context,
_outputPipe = pipe,
_localsTuple = MutableTuple.MakeTuple(localsTupleType, DottedLocalsNameIndexMap)
};
if (usingValues != null)
{
PSBoundParametersDictionary dictionary = new PSBoundParametersDictionary {
ImplicitUsingParameters = usingValues
};
arg._localsTuple.SetAutomaticVariable(AutomaticVariable.PSBoundParameters, dictionary, context);
}
object obj3 = lambda(arg);
if (obj3 == AutomationNull.Value)
{
return ((resultList.Count == 0) ? null : PipelineOps.PipelineResult(resultList));
}
obj4 = obj3;
}
catch (TargetInvocationException exception)
{
throw exception.InnerException;
}
}
catch (TerminateException)
{
throw;
}
catch (FlowControlException)
{
obj4 = null;
}
finally
{
context.EngineSessionState = engineSessionState;
}
return obj4;
}
private static object GetExpressionValue(ExpressionAst expressionAst,
bool isTrustedInput,
ExecutionContext context,
SessionStateInternal sessionStateInternal,
IDictionary usingValues,
ref Func<FunctionContext, object> lambda,
ref IScriptExtent[] sequencePoints,
ref Type localsTupleType)
{
object constantValue;
if (IsConstantValueVisitor.IsConstant(expressionAst, out constantValue))
{
return constantValue;
}
// If this isn't trusted input, then just return.
if (!isTrustedInput)
{
return null;
}
// Can't be exposed to untrusted input - exposing private variable names / etc. could be
// information disclosure.
var variableAst = expressionAst as VariableExpressionAst;
if (variableAst != null)
{
// We can avoid creating a lambda for the common case of a simple variable expression.
return VariableOps.GetVariableValue(variableAst.VariablePath, context, variableAst);
}
// Can't be exposed to untrusted input - invoking arbitrary code could result in remote code
// execution.
if (lambda == null)
{
lambda = (new Compiler()).CompileSingleExpression(expressionAst, out sequencePoints, out localsTupleType);
}
SessionStateInternal oldSessionState = context.EngineSessionState;
try
{
if (sessionStateInternal != null && context.EngineSessionState != sessionStateInternal)
{
// If we're running a function from a module, we need to evaluate the initializers in the
// module context, not the callers context...
context.EngineSessionState = sessionStateInternal;
}
var resultList = new List<object>();
var pipe = new Pipe(resultList);
try
{
var functionContext = new FunctionContext
{
_sequencePoints = sequencePoints,
_executionContext = context,
_file = expressionAst.Extent.File,
_outputPipe = pipe,
_localsTuple = MutableTuple.MakeTuple(localsTupleType, DottedLocalsNameIndexMap)
};
if (usingValues != null)
{
var boundParameters = new PSBoundParametersDictionary { ImplicitUsingParameters = usingValues };
functionContext._localsTuple.SetAutomaticVariable(AutomaticVariable.PSBoundParameters, boundParameters, context);
}
var result = lambda(functionContext);
if (result == AutomationNull.Value)
{
return resultList.Count == 0 ? null : PipelineOps.PipelineResult(resultList);
}
return result;
}
catch (TargetInvocationException tie)
{
throw tie.InnerException;
}
}
catch (TerminateException)
{
// the debugger is terminating the execution; bubble up the exception
throw;
}
catch (FlowControlException)
{
// ignore break, continue and return exceptions
return null;
}
finally
{
context.EngineSessionState = oldSessionState;
}
}
