System.Xen

Haskell bidings to Xen hypervisor interface. There are three interface levels in this library:

• Low-level interface. System.Xen.Low. It just provides bindings to c-calls.
• Mid-level interface. System.Xen.Mid. Contains helper functions and allow to use your favorite Monad.
• High-level interface. System.Xen.High. Contains Xen monad and provides a safe way to run any Xen computation.

Last one is also re-exported by current module and intend for common usage. Usage example:

 module Main (main) where

 import System.Xen (runXen, domainGetInfo)

 main :: IO ()
 main = print =<< runXen domainGetInfo

Errors

data XcHandleOpenError

This error can be raised if handle can not be opened, insufficient rights for example.

Constructors

XcHandleOpenError Errno

Instances

Eq XcHandleOpenError

Ord XcHandleOpenError

Show XcHandleOpenError

Typeable XcHandleOpenError

Exception XcHandleOpenError

data InvalidDomainShutdownReason

This error can be raised if peecked value of DomainShutdownReason is not expected.

Constructors

InvalidDomainShutdownReason CInt

Peeked value

Instances

Eq InvalidDomainShutdownReason

Ord InvalidDomainShutdownReason

Show InvalidDomainShutdownReason

Typeable InvalidDomainShutdownReason

Exception InvalidDomainShutdownReason

data DomainGetInfoError

This error can be raised if any error occured during receiving the list, for example: try to to fetch a list in domU.

Constructors

DomainGetInfoError Errno

Instances

Eq DomainGetInfoError

Ord DomainGetInfoError

Show DomainGetInfoError

Typeable DomainGetInfoError

Exception DomainGetInfoError

Domain info

newtype DomId

Domain id, wrapper around Word32.

Constructors

DomId

Fields

unDomId :: Word32

Instances

Eq DomId

Ord DomId

Show DomId

Storable DomId

data DomainFlag

Domain flags. It's translated from xc_dominfo structure, so it's possible to be mutual exclusion flags in one domain, e.g. DomainFlagShutdown and DomainFlagRunning.

Constructors

DomainFlagDying

DomainFlagCrashed

DomainFlagShutdown

DomainFlagPaused

DomainFlagBlocked

DomainFlagRunning

DomainFlagHVM

DomainFlagDebugged

Instances

Enum DomainFlag

Eq DomainFlag

Ord DomainFlag

Show DomainFlag

data DomainShutdownReason

Domain shutdown reason it's only meaningful if domain has DomainFlagShutdown flag.

Constructors

DomainShutdownReasonPoweroff

DomainShutdownReasonReboot

DomainShutdownReasonSuspend

DomainShutdownReasonCrash

DomainShutdownReasonWatchdog

Instances

Eq DomainShutdownReason

Ord DomainShutdownReason

Show DomainShutdownReason

Storable DomainShutdownReason

Constats used in this instance defined in xen/sched.h.

data DomainInfo

Information about a single domain.

Constructors

DomainInfo

Fields

domainInfoId :: !DomId

domainInfoSsidRef :: !Word32

domainInfoFlags :: BitSet DomainFlag

domainInfoShutdownReason :: Maybe DomainShutdownReason

domainInfoNumberOfPages :: !Word32

domainInfoNumberOfSharedPages :: !Word32

domainInfoSharedInfoFrame :: !Word32

domainInfoCpuTime :: !Word64

domainInfoMaxMemKb :: !Word32

domainInfoNubmerOfOnlineVcpus :: !Word32

domainInfoMaxVcpuId :: !Word32

domainInfoDomHandle :: UUID

domainInfoCpuPool :: !Word32

Instances

Eq DomainInfo

Ord DomainInfo

Show DomainInfo

Storable DomainInfo

High-level API

data Xen a

This is a special monad for operations with XenCtrl, it's a wrapper around ReaderT transformer and it controls the connection to the hypervisor. Because Xen has instances of and MonadBase and MonadBaseControl over IO, you can use any functions of lifted-base library, or any IO with liftBase.

Instances

Monad Xen

Functor Xen

Applicative Xen

MonadBase IO Xen

MonadBaseControl IO Xen

domainGetInfo :: Xen [DomainInfo]

Returns a lift of domains, this function can fail with InvalidDomainShutdownReason and DomainGetInfoError.

runXen :: MonadBaseControl IO m => Xen a -> m (Either SomeException a)

Open new connection to the hypervisor, run any Xen action and close connection if nessesary. This function can fail with Either SomeException with XcHandleOpenError and any error of providing Xen action.