host

package
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 Go to latest Published: Jan 24, 2021 License: Apache-2.0, MIT Imports: 35 Imported by: 0

Documentation

Overview

Package host provides a filesystem implementation for host files imported as file descriptors.

Index

Constants

View Source 
const ConnectedEndpointenableLogging = false

enableLogging indicates whether reference-related events should be logged (with stack traces). This is false by default and should only be set to true for debugging purposes, as it can generate an extremely large amount of output and drastically degrade performance.

Variables

This section is empty.

Functions

func ImportFD 

func ImportFD(ctx context.Context, mnt *vfs.Mount, hostFD int, isTTY bool) (*vfs.FileDescription, error)

ImportFD sets up and returns a vfs.FileDescription from a donated fd.

func NewFD 

func NewFD(ctx context.Context, mnt *vfs.Mount, hostFD int, opts *NewFDOptions) (*vfs.FileDescription, error)

NewFD returns a vfs.FileDescription representing the given host file descriptor. mnt must be Kernel.HostMount().

func NewFilesystem 

func NewFilesystem(vfsObj *vfs.VirtualFilesystem) (*vfs.Filesystem, error)

NewFilesystem sets up and returns a new hostfs filesystem.

Note that there should only ever be one instance of host.filesystem, a global mount for host fds.

Types

type ConnectedEndpoint 

type ConnectedEndpoint struct {
	ConnectedEndpointRefs
	// contains filtered or unexported fields
}

ConnectedEndpoint is an implementation of transport.ConnectedEndpoint and transport.Receiver. It is backed by a host fd that was imported at sentry startup. This fd is shared with a hostfs inode, which retains ownership of it.

ConnectedEndpoint is saveable, since we expect that the host will provide the same fd upon restore.

As of this writing, we only allow Unix sockets to be imported.

+stateify savable 

var ConnectedEndpointobj *ConnectedEndpoint

obj is used to customize logging. Note that we use a pointer to T so that we do not copy the entire object when passed as a format parameter.

func NewConnectedEndpoint 

func NewConnectedEndpoint(ctx context.Context, hostFD int, addr string, saveable bool) (*ConnectedEndpoint, *syserr.Error)

NewConnectedEndpoint creates a new ConnectedEndpoint backed by a host fd imported at sentry startup,

The caller is responsible for calling Init(). Additionaly, Release needs to be called twice because ConnectedEndpoint is both a transport.Receiver and transport.ConnectedEndpoint.

func (*ConnectedEndpoint) CloseNotify 

func (c *ConnectedEndpoint) CloseNotify()

CloseNotify implements transport.ConnectedEndpoint.CloseNotify.

func (*ConnectedEndpoint) CloseRecv 

func (c *ConnectedEndpoint) CloseRecv()

CloseRecv implements transport.Receiver.CloseRecv.

func (*ConnectedEndpoint) CloseSend 

func (c *ConnectedEndpoint) CloseSend()

CloseSend implements transport.ConnectedEndpoint.CloseSend.

func (*ConnectedEndpoint) CloseUnread 

func (c *ConnectedEndpoint) CloseUnread()

CloseUnread implements transport.ConnectedEndpoint.CloseUnread.

func (*ConnectedEndpoint) EventUpdate 

func (c *ConnectedEndpoint) EventUpdate()

EventUpdate implements transport.ConnectedEndpoint.EventUpdate.

func (*ConnectedEndpoint) GetLocalAddress 

func (c *ConnectedEndpoint) GetLocalAddress() (tcpip.FullAddress, *tcpip.Error)

GetLocalAddress implements transport.ConnectedEndpoint.GetLocalAddress.

func (*ConnectedEndpoint) Passcred 

func (c *ConnectedEndpoint) Passcred() bool

Passcred implements transport.ConnectedEndpoint.Passcred.

func (*ConnectedEndpoint) Readable 

func (c *ConnectedEndpoint) Readable() bool

Readable implements transport.Receiver.Readable.

func (*ConnectedEndpoint) Recv 

func (c *ConnectedEndpoint) Recv(ctx context.Context, data [][]byte, creds bool, numRights int, peek bool) (int64, int64, transport.ControlMessages, bool, tcpip.FullAddress, bool, *syserr.Error)

Recv implements transport.Receiver.Recv.

func (*ConnectedEndpoint) RecvMaxQueueSize 

func (c *ConnectedEndpoint) RecvMaxQueueSize() int64

RecvMaxQueueSize implements transport.Receiver.RecvMaxQueueSize.

func (*ConnectedEndpoint) RecvNotify 

func (c *ConnectedEndpoint) RecvNotify()

RecvNotify implements transport.Receiver.RecvNotify.

func (*ConnectedEndpoint) RecvQueuedSize 

func (c *ConnectedEndpoint) RecvQueuedSize() int64

RecvQueuedSize implements transport.Receiver.RecvQueuedSize.

func (*ConnectedEndpoint) Release 

func (c *ConnectedEndpoint) Release(ctx context.Context)

Release implements transport.ConnectedEndpoint.Release and transport.Receiver.Release.

func (*ConnectedEndpoint) Send 

func (c *ConnectedEndpoint) Send(ctx context.Context, data [][]byte, controlMessages transport.ControlMessages, from tcpip.FullAddress) (int64, bool, *syserr.Error)

Send implements transport.ConnectedEndpoint.Send.

func (*ConnectedEndpoint) SendMaxQueueSize 

func (c *ConnectedEndpoint) SendMaxQueueSize() int64

SendMaxQueueSize implements transport.Receiver.SendMaxQueueSize.

func (*ConnectedEndpoint) SendNotify 

func (c *ConnectedEndpoint) SendNotify()

SendNotify implements transport.ConnectedEndpoint.SendNotify.

func (*ConnectedEndpoint) SendQueuedSize 

func (c *ConnectedEndpoint) SendQueuedSize() int64

SendQueuedSize implements transport.Receiver.SendQueuedSize.

func (*ConnectedEndpoint) StateFields 

func (c *ConnectedEndpoint) StateFields() []string

func (*ConnectedEndpoint) StateLoad 

func (c *ConnectedEndpoint) StateLoad(stateSourceObject state.Source)

func (*ConnectedEndpoint) StateSave 

func (c *ConnectedEndpoint) StateSave(stateSinkObject state.Sink)

func (*ConnectedEndpoint) StateTypeName 

func (c *ConnectedEndpoint) StateTypeName() string

func (*ConnectedEndpoint) Writable 

func (c *ConnectedEndpoint) Writable() bool

Writable implements transport.ConnectedEndpoint.Writable.

type ConnectedEndpointRefs 

type ConnectedEndpointRefs struct {
	// contains filtered or unexported fields
}

Refs implements refs.RefCounter. It keeps a reference count using atomic operations and calls the destructor when the count reaches zero.

+stateify savable

func (*ConnectedEndpointRefs) DecRef 

func (r *ConnectedEndpointRefs) DecRef(destroy func())

DecRef implements refs.RefCounter.DecRef.

Note that speculative references are counted here. Since they were added prior to real references reaching zero, they will successfully convert to real references. In other words, we see speculative references only in the following case: 

A: TryIncRef [speculative increase => sees non-negative references]
B: DecRef [real decrease]
A: TryIncRef [transform speculative to real]

func (*ConnectedEndpointRefs) IncRef 

func (r *ConnectedEndpointRefs) IncRef()

IncRef implements refs.RefCounter.IncRef.

func (*ConnectedEndpointRefs) InitRefs 

func (r *ConnectedEndpointRefs) InitRefs()

InitRefs initializes r with one reference and, if enabled, activates leak checking.

func (*ConnectedEndpointRefs) LeakMessage 

func (r *ConnectedEndpointRefs) LeakMessage() string

LeakMessage implements refsvfs2.CheckedObject.LeakMessage.

func (*ConnectedEndpointRefs) LogRefs 

func (r *ConnectedEndpointRefs) LogRefs() bool

LogRefs implements refsvfs2.CheckedObject.LogRefs.

func (*ConnectedEndpointRefs) ReadRefs 

func (r *ConnectedEndpointRefs) ReadRefs() int64

ReadRefs returns the current number of references. The returned count is inherently racy and is unsafe to use without external synchronization.

func (*ConnectedEndpointRefs) RefType 

func (r *ConnectedEndpointRefs) RefType() string

RefType implements refsvfs2.CheckedObject.RefType.

func (*ConnectedEndpointRefs) StateFields 

func (r *ConnectedEndpointRefs) StateFields() []string

func (*ConnectedEndpointRefs) StateLoad 

func (r *ConnectedEndpointRefs) StateLoad(stateSourceObject state.Source)

func (*ConnectedEndpointRefs) StateSave 

func (r *ConnectedEndpointRefs) StateSave(stateSinkObject state.Sink)

func (*ConnectedEndpointRefs) StateTypeName 

func (r *ConnectedEndpointRefs) StateTypeName() string

func (*ConnectedEndpointRefs) TryIncRef 

func (r *ConnectedEndpointRefs) TryIncRef() bool

TryIncRef implements refs.RefCounter.TryIncRef.

To do this safely without a loop, a speculative reference is first acquired on the object. This allows multiple concurrent TryIncRef calls to distinguish other TryIncRef calls from genuine references held.

type NewFDOptions 

type NewFDOptions struct {
	// If Savable is true, the host file descriptor may be saved/restored by
	// numeric value; the sandbox API requires a corresponding host FD with the
	// same numeric value to be provieded at time of restore.
	Savable bool

	// If IsTTY is true, the file descriptor is a TTY.
	IsTTY bool

	// If HaveFlags is true, use Flags for the new file description. Otherwise,
	// the new file description will inherit flags from hostFD.
	HaveFlags bool
	Flags     uint32
}

NewFDOptions contains options to NewFD.

type SCMConnectedEndpoint 

type SCMConnectedEndpoint struct {
	ConnectedEndpoint
	// contains filtered or unexported fields
}

SCMConnectedEndpoint represents an endpoint backed by a host fd that was passed through a gofer Unix socket. It resembles ConnectedEndpoint, with the following differences: - SCMConnectedEndpoint is not saveable, because the host cannot guarantee the same descriptor number across S/R. - SCMConnectedEndpoint holds ownership of its fd and notification queue.

func NewSCMEndpoint 

func NewSCMEndpoint(ctx context.Context, hostFD int, queue *waiter.Queue, addr string) (*SCMConnectedEndpoint, *syserr.Error)

NewSCMEndpoint creates a new SCMConnectedEndpoint backed by a host fd that was passed through a Unix socket.

The caller is responsible for calling Init(). Additionaly, Release needs to be called twice because ConnectedEndpoint is both a transport.Receiver and transport.ConnectedEndpoint.

func (*SCMConnectedEndpoint) Init 

func (e *SCMConnectedEndpoint) Init() error

Init will do the initialization required without holding other locks.

func (*SCMConnectedEndpoint) Release 

func (e *SCMConnectedEndpoint) Release(ctx context.Context)

Release implements transport.ConnectedEndpoint.Release and transport.Receiver.Release.

type TTYFileDescription 

type TTYFileDescription struct {
	// contains filtered or unexported fields
}

TTYFileDescription implements vfs.FileDescriptionImpl for a host file descriptor that wraps a TTY FD.

+stateify savable

func (*TTYFileDescription) Allocate 

func (f *TTYFileDescription) Allocate(ctx context.Context, mode, offset, length uint64) error

Allocate implements vfs.FileDescriptionImpl.Allocate.

func (*TTYFileDescription) ConfigureMMap 

func (f *TTYFileDescription) ConfigureMMap(_ context.Context, opts *memmap.MMapOpts) error

ConfigureMMap implements vfs.FileDescriptionImpl.ConfigureMMap.

func (*TTYFileDescription) EventRegister 

func (f *TTYFileDescription) EventRegister(e *waiter.Entry, mask waiter.EventMask)

EventRegister implements waiter.Waitable.EventRegister.

func (*TTYFileDescription) EventUnregister 

func (f *TTYFileDescription) EventUnregister(e *waiter.Entry)

EventUnregister implements waiter.Waitable.EventUnregister.

func (*TTYFileDescription) ForegroundProcessGroup 

func (t *TTYFileDescription) ForegroundProcessGroup() *kernel.ProcessGroup

ForegroundProcessGroup returns the foreground process for the TTY.

func (*TTYFileDescription) InitForegroundProcessGroup 

func (t *TTYFileDescription) InitForegroundProcessGroup(pg *kernel.ProcessGroup)

InitForegroundProcessGroup sets the foreground process group and session for the TTY. This should only be called once, after the foreground process group has been created, but before it has started running.

func (*TTYFileDescription) Ioctl 

func (t *TTYFileDescription) Ioctl(ctx context.Context, io usermem.IO, args arch.SyscallArguments) (uintptr, error)

Ioctl implements vfs.FileDescriptionImpl.Ioctl.

func (*TTYFileDescription) PRead 

func (t *TTYFileDescription) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error)

PRead implements vfs.FileDescriptionImpl.PRead.

Reading from a TTY is only allowed for foreground process groups. Background process groups will either get EIO or a SIGTTIN.

func (*TTYFileDescription) PWrite 

func (t *TTYFileDescription) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error)

PWrite implements vfs.FileDescriptionImpl.PWrite.

func (*TTYFileDescription) Read 

func (t *TTYFileDescription) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error)

Read implements vfs.FileDescriptionImpl.Read.

Reading from a TTY is only allowed for foreground process groups. Background process groups will either get EIO or a SIGTTIN.

func (*TTYFileDescription) Readiness 

func (f *TTYFileDescription) Readiness(mask waiter.EventMask) waiter.EventMask

Readiness uses the poll() syscall to check the status of the underlying FD.

func (*TTYFileDescription) Release 

func (t *TTYFileDescription) Release(ctx context.Context)

Release implements fs.FileOperations.Release.

func (*TTYFileDescription) Seek 

func (f *TTYFileDescription) Seek(_ context.Context, offset int64, whence int32) (int64, error)

Seek implements vfs.FileDescriptionImpl.Seek.

Note that we do not support seeking on directories, since we do not even allow directory fds to be imported at all.

func (*TTYFileDescription) SetStat 

func (f *TTYFileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions) error

SetStat implements vfs.FileDescriptionImpl.SetStat.

func (*TTYFileDescription) Stat 

func (f *TTYFileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error)

Stat implements vfs.FileDescriptionImpl.Stat.

func (*TTYFileDescription) StateFields 

func (t *TTYFileDescription) StateFields() []string

func (*TTYFileDescription) StateLoad 

func (t *TTYFileDescription) StateLoad(stateSourceObject state.Source)

func (*TTYFileDescription) StateSave 

func (t *TTYFileDescription) StateSave(stateSinkObject state.Sink)

func (*TTYFileDescription) StateTypeName 

func (t *TTYFileDescription) StateTypeName() string

func (*TTYFileDescription) Sync 

func (f *TTYFileDescription) Sync(ctx context.Context) error

Sync implements vfs.FileDescriptionImpl.Sync.

func (*TTYFileDescription) Write 

func (t *TTYFileDescription) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error)

Write implements vfs.FileDescriptionImpl.Write.

Source Files

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