LIO.Error

This module exports exception types thrown in response to label failures. In addition, it provides withContext, a function that annotates any exceptions in the AnyLabelError hierarchy that are thrown within a given scope. These annotations should be used to add function names to exceptions, so as to make it easier to pinpoint the cause of a label error.

Documentation

class Annotatable e where

Class of error messages that can be annotated with context.

Methods

annotate :: String -> e -> e

Instances

Annotatable InsufficientPrivs

Annotatable AnyLabelError

Annotatable (ResultExceedsLabel l)

Annotatable (LabelError l)

withContext :: String -> LIO l a -> LIO l a

Executes an action with a context string, which will be added to any label exception thrown.

Note: this function wraps an action with a catch, and thus may incur a small runtime cost (though it is well under 100 ns on machines we benchmarked).

data AnyLabelError

Parent of all label-related exceptions.

Constructors

forall e . (Exception e, Annotatable e) => AnyLabelError e

Instances

Show AnyLabelError

Typeable AnyLabelError

Exception AnyLabelError

Annotatable AnyLabelError

lerrToException :: (Exception e, Annotatable e) => e -> SomeException

Definition of toException for children of AnyLabelError in the exception hierarchy.

lerrFromException :: Exception e => SomeException -> Maybe e

Definition of fromException for children of AnyLabelError in the exception hierarchy.

data GenericPrivDesc l

A generic privilege description for recording relevant privileges in exceptions.

Constructors

forall p . PrivDesc l p => GenericPrivDesc p

Instances

Show (GenericPrivDesc l)

data LabelError l

Main error type thrown by label failures in the LIO monad.

Constructors

LabelError

Fields

lerrContext :: [String]

Annotation of where the failure happened.

lerrFailure :: String

Actual function that failed.

lerrCurLabel :: l

Current label at time of error.

lerrCurClearance :: l

Current clearance at time of error.

lerrPrivs :: [GenericPrivDesc l]

Any privileges involved in error.

lerrLabels :: [l]

Any labels involved in error.

Instances

Typeable1 LabelError

Show l => Show (LabelError l)

Label l => Exception (LabelError l)

Annotatable (LabelError l)

labelError

Arguments

:: Label l

=> String

Function that failed.

-> [l]

Labels involved in error.

-> LIO l a

Throw a label-error exception.

labelErrorP

Arguments

:: (Label l, PrivDesc l p)

=> String

Function that failed.

-> Priv p

Privileges involved.

-> [l]

Labels involved.

-> LIO l a

Throw a label-error exception.

data InsufficientPrivs

Error indicating insufficient privileges (independent of the current label). This exception is thrown by delegate, and should also be thrown by gates that receive insufficient privilege descriptions (see LIO.Delegate).

Constructors

forall p . SpeaksFor p => InsufficientPrivs

Fields

inspContext :: [String]

inspFailure :: String

inspSupplied :: p

inspNeeded :: p

Instances

Show InsufficientPrivs

Typeable InsufficientPrivs

Exception InsufficientPrivs

Annotatable InsufficientPrivs

insufficientPrivs

Arguments

:: SpeaksFor p

=> String

Function in which error occurs

-> p

Description of privileges supplied

-> p

Description of privileges needed

-> a

Raise InsufficientPrivs error.

data ResultExceedsLabel l

Error raised when a computation spawned by lFork terminates with its current label above the label of the result.

Constructors

ResultExceedsLabel

Fields

relContext :: [String]

relLocation :: String

relDeclaredLabel :: l

relActualLabel :: Maybe l

Instances

Typeable1 ResultExceedsLabel

Show l => Show (ResultExceedsLabel l)

Label l => Exception (ResultExceedsLabel l)

Annotatable (ResultExceedsLabel l)