rootfs

Documentation

Overview

Package rootfs encapsulates the container's root filesystem.

Index

• type ErrorId
• type ImplErrorId
• type RootFS
  • func NewRootFS(sc syscall.SyscallFS, f fileutils.Fileutils, rwBaseDir string) (RootFS, gerror.Gerror)

Types

type ErrorId

type ErrorId int

ErrorId is used for error ids relating to the RootFS interface.

const (
	ErrCreateTempDir ErrorId = iota // a temporary directory for the read-write layer could not be created
	ErrCreateMountDir
	ErrBindMountRoot
	ErrBindMountSubdir
	ErrRootSubdirMissing
	ErrUnmountSubdir
	ErrOverlayTempDir
	ErrOverlayDir
	ErrRemoveMountDir
	ErrUnmountRoot
)

type ImplErrorId

type ImplErrorId int

ImplErrorId is used for error ids relating to the implementation of this package.

const (
	ErrNilSyscallFS     ImplErrorId = iota // the SyscallFS value was nil
	ErrRwBaseDirMissing                    // the read-write base directory was not found
	ErrRwBaseDirIsFile                     // a file was found instead of the read-write base directory
	ErrRwBaseDirNotRw                      // the read-write base directory does not have read and write permissions
)

type RootFS

type RootFS interface {
	/*
		Generate produces a usable root filesystem instance from a
		"prototype" root filesystem.

		The input parameter `prototype` is the path of the prototype,
		which may be any filesystem directory. Generate does not modify
		the prototype.

		The resultant filesystem is a collection of read-write
		directories overlaid on the prototype. If an overlay filesystem,
		such as `aufs` or `overlayfs`, is available, it will be used to
		create the result. Otherwise, the result is a mounted filesystem
		consisting of a patchwork quilt of read-write temporary directories
		and the prototype. TODO: decide which of these to support.

		If Generate fails, it has no side-effects other than possibly
		creating some directories in the read-write base directory.

		The return values are the path of the generated root filesystem
		and an error. The error is `nil` if and only if Generate was
		successful.

		Generate is a replacement for garden's `hook-parent-before-clone.sh`
		script, except that Generate does not copy `wshd` into the
		generated filesystem.
	*/
	Generate(prototype string) (string, gerror.Gerror)

	/*
		Remove a previously generated root filesystem.
	*/
	Remove(root string) gerror.Gerror
}

func NewRootFS

func NewRootFS(sc syscall.SyscallFS, f fileutils.Fileutils, rwBaseDir string) (RootFS, gerror.Gerror)

Creates a new RootFS instance which uses the given SyscallFS interface and the given read-write directory as a base for the writable portion of generated root filesystems. The SyscallFS interface value must not be nil to ensure that the caller has sufficient privileges to perform mounts, etc.