Safe Haskell	None
Language	Haskell2010

System.CGroup.Controller.Internal

Contents

CGroup Controllers
CGroups
Mounts
Internal intermediate operations

Description

Internal types and functions for cgroup controllers

Synopsis

newtype Controller a = Controller {
- unController :: Path Abs Dir
}
resolveCGroupController :: Text -> IO (Controller a)
resolveCGroupController' :: Path Abs File -> Path Abs File -> Text -> IO (Controller a)
data CGroup = CGroup {
- controlGroupControllers :: [Text]
- controlGroupPath :: Path Abs Dir
}
data Mount = Mount {
- mountId :: Text
- mountParentId :: Text
- mountStDev :: Text
- mountRoot :: Path Abs Dir
- mountPoint :: Path Abs Dir
- mountOptions :: Text
- mountTags :: [Text]
- mountFilesystemType :: Text
- mountSource :: Text
- mountSuperOptions :: [Text]
}
findMatchingCGroup :: Text -> [CGroup] -> Maybe CGroup
resolveControllerMountPath :: Text -> CGroup -> [Mount] -> Maybe (Path Abs Dir)
tryResolveMount :: Text -> CGroup -> Mount -> Maybe (Path Abs Dir)
parseMountInfo :: Parser [Mount]
parseCGroups :: Parser [CGroup]
type Parser = Parsec Void Text

CGroup Controllers

newtype Controller a Source #

A CGroup controller path for a specific subsystem

Constructors

Controller
Fields unController :: Path Abs Dir

Instances

Instances details

Eq (Controller a) Source #
Instance details Defined in System.CGroup.Controller.Internal Methods (==) :: Controller a -> Controller a -> Bool # (/=) :: Controller a -> Controller a -> Bool #
Ord (Controller a) Source #
Instance details Defined in System.CGroup.Controller.Internal Methods compare :: Controller a -> Controller a -> Ordering # (<) :: Controller a -> Controller a -> Bool # (<=) :: Controller a -> Controller a -> Bool # (>) :: Controller a -> Controller a -> Bool # (>=) :: Controller a -> Controller a -> Bool # max :: Controller a -> Controller a -> Controller a # min :: Controller a -> Controller a -> Controller a #
Show (Controller a) Source #
Instance details Defined in System.CGroup.Controller.Internal Methods showsPrec :: Int -> Controller a -> ShowS # show :: Controller a -> String # showList :: [Controller a] -> ShowS #

resolveCGroupController :: Text -> IO (Controller a) Source #

Resolve a CGroup controller by name, as viewed by the current process

see cgroups(7): /proc/self/cgroup is a file that contains information about control groups applied to this process

see proc(5): /proc/self/mountinfo is a file that contains information about mounts available to this process

Throws an Exception when the controller is not able to be found, or when running outside of a cgroup

resolveCGroupController' :: Path Abs File -> Path Abs File -> Text -> IO (Controller a) Source #

Resolve a CGroup controller by name, under the given cgroup and mountinfo paths

Throws an Exception when the controller is not able to be found, or when running outside of a cgroup

CGroups

data CGroup Source #

A cgroup, as viewed within /proc/[pid]/cgroup

see cgroups(7): /proc/[pid]/cgroup section

Constructors

CGroup
Fields controlGroupControllers :: [Text] controlGroupPath :: Path Abs Dir

Instances

Instances details

Show CGroup Source #
Instance details Defined in System.CGroup.Controller.Internal Methods showsPrec :: Int -> CGroup -> ShowS # show :: CGroup -> String # showList :: [CGroup] -> ShowS #

Mounts

data Mount Source #

A mount, as viewed within /proc/[pid]/mountinfo

see proc(5): /proc/[pid]/mountinfo section

Constructors

Mount
Fields mountId :: Text mountParentId :: Text mountStDev :: Text mountRoot :: Path Abs Dir mountPoint :: Path Abs Dir mountOptions :: Text mountTags :: [Text] mountFilesystemType :: Text mountSource :: Text mountSuperOptions :: [Text]

Instances

Instances details

Show Mount Source #
Instance details Defined in System.CGroup.Controller.Internal Methods showsPrec :: Int -> Mount -> ShowS # show :: Mount -> String # showList :: [Mount] -> ShowS #

Internal intermediate operations

findMatchingCGroup :: Text -> [CGroup] -> Maybe CGroup Source #

Find a CGroup matching a controller name

For cgroups version 1, we use containsController to explicitly look for the controller within a cgroup

For cgroups version 2, we use emptyControllers to find a cgroup without any controllers

see cgroups(7): /proc/[pid]/cgroup section

resolveControllerMountPath :: Text -> CGroup -> [Mount] -> Maybe (Path Abs Dir) Source #

Find a Mount matching a controller name and cgroup, returning the absolute resolved path of a controller

tryResolveMount :: Text -> CGroup -> Mount -> Maybe (Path Abs Dir) Source #

Attempt to match a cgroup controller to a mount, returning the absolute resolved path of the controller

Returns Nothing if the mount does not match the cgroup controller

A matching mount must have a filesystem type of "cgroup" and contain the controller name within its "super options".

Per cgroups(7), the cgroup path is relative to a mount root in the process's mount hierarchy. Notably, a mount root is not the same as its mount point. A mount point is the path at which the mount is visible to the process.

As such, we need to look for a mount whose mount root either..

..exactly matches our cgroup's path, in which case we directly return the mount's mount path; OR
..is a prefix of our cgroup's path, in which case we return the relative path from the mount root appended to the mount's mount path

parseMountInfo :: Parser [Mount] Source #

Parse an entire /proc/[pid]/mountinfo file into a list of mounts

parseCGroups :: Parser [CGroup] Source #

Parse an entire /proc/[pid]/cgroup file into a list of cgroups

type Parser = Parsec Void Text Source #

Megaparsec Parser