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.

Minimal complete definition

annotate

Methods

annotate :: String -> e -> e

Instances

Annotatable InsufficientPrivs

Methods

annotate :: String -> InsufficientPrivs -> InsufficientPrivs

Annotatable AnyLabelError

Methods

annotate :: String -> AnyLabelError -> AnyLabelError

Annotatable (ResultExceedsLabel l)

Methods

annotate :: String -> ResultExceedsLabel l -> ResultExceedsLabel l

Annotatable (LabelError l)

Methods

annotate :: String -> LabelError l -> 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

(Exception e, Annotatable e) => AnyLabelError e

Instances

Show AnyLabelError

Methods

showsPrec :: Int -> AnyLabelError -> ShowS

show :: AnyLabelError -> String

showList :: [AnyLabelError] -> ShowS

Exception AnyLabelError

Methods

toException :: AnyLabelError -> SomeException

fromException :: SomeException -> Maybe AnyLabelError

displayException :: AnyLabelError -> String

Annotatable AnyLabelError

Methods

annotate :: String -> AnyLabelError -> 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

PrivDesc l p => GenericPrivDesc p

Instances

Show (GenericPrivDesc l)

Methods

showsPrec :: Int -> GenericPrivDesc l -> ShowS

show :: GenericPrivDesc l -> String

showList :: [GenericPrivDesc l] -> ShowS

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

Show l => Show (LabelError l)

Methods

showsPrec :: Int -> LabelError l -> ShowS

show :: LabelError l -> String

showList :: [LabelError l] -> ShowS

Label l => Exception (LabelError l)

Methods

toException :: LabelError l -> SomeException

fromException :: SomeException -> Maybe (LabelError l)

displayException :: LabelError l -> String

Annotatable (LabelError l)

Methods

annotate :: String -> LabelError l -> 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

SpeaksFor p => InsufficientPrivs

Fields

• inspContext :: [String]
• inspFailure :: String
• inspSupplied :: p
• inspNeeded :: p

Instances

Show InsufficientPrivs

Methods

showsPrec :: Int -> InsufficientPrivs -> ShowS

show :: InsufficientPrivs -> String

showList :: [InsufficientPrivs] -> ShowS

Exception InsufficientPrivs

Methods

toException :: InsufficientPrivs -> SomeException

fromException :: SomeException -> Maybe InsufficientPrivs

displayException :: InsufficientPrivs -> String

Annotatable InsufficientPrivs

Methods

annotate :: String -> InsufficientPrivs -> 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

Show l => Show (ResultExceedsLabel l)

Methods

showsPrec :: Int -> ResultExceedsLabel l -> ShowS

show :: ResultExceedsLabel l -> String

showList :: [ResultExceedsLabel l] -> ShowS

Label l => Exception (ResultExceedsLabel l)

Methods

toException :: ResultExceedsLabel l -> SomeException

fromException :: SomeException -> Maybe (ResultExceedsLabel l)

displayException :: ResultExceedsLabel l -> String

Annotatable (ResultExceedsLabel l)

Methods

annotate :: String -> ResultExceedsLabel l -> ResultExceedsLabel l