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// Copyright 2020 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package hostinet
import (
"syscall"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/fdnotifier"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/sockfs"
"gvisor.dev/gvisor/pkg/sentry/hostfd"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/socket"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/syserr"
"gvisor.dev/gvisor/pkg/syserror"
"gvisor.dev/gvisor/pkg/usermem"
"gvisor.dev/gvisor/pkg/waiter"
)
type socketVFS2 struct {
vfsfd vfs.FileDescription
vfs.FileDescriptionDefaultImpl
// We store metadata for hostinet sockets internally. Technically, we should
// access metadata (e.g. through stat, chmod) on the host for correctness,
// but this is not very useful for inet socket fds, which do not belong to a
// concrete file anyway.
vfs.DentryMetadataFileDescriptionImpl
socketOpsCommon
}
var _ = socket.SocketVFS2(&socketVFS2{})
func newVFS2Socket(t *kernel.Task, family int, stype linux.SockType, protocol int, fd int, flags uint32) (*vfs.FileDescription, *syserr.Error) {
mnt := t.Kernel().SocketMount()
d := sockfs.NewDentry(t.Credentials(), mnt)
s := &socketVFS2{
socketOpsCommon: socketOpsCommon{
family: family,
stype: stype,
protocol: protocol,
fd: fd,
},
}
if err := fdnotifier.AddFD(int32(fd), &s.queue); err != nil {
return nil, syserr.FromError(err)
}
vfsfd := &s.vfsfd
if err := vfsfd.Init(s, linux.O_RDWR|(flags&linux.O_NONBLOCK), mnt, d, &vfs.FileDescriptionOptions{
DenyPRead: true,
DenyPWrite: true,
UseDentryMetadata: true,
}); err != nil {
return nil, syserr.FromError(err)
}
return vfsfd, nil
}
// Readiness implements waiter.Waitable.Readiness.
func (s *socketVFS2) Readiness(mask waiter.EventMask) waiter.EventMask {
return s.socketOpsCommon.Readiness(mask)
}
// EventRegister implements waiter.Waitable.EventRegister.
func (s *socketVFS2) EventRegister(e *waiter.Entry, mask waiter.EventMask) {
s.socketOpsCommon.EventRegister(e, mask)
}
// EventUnregister implements waiter.Waitable.EventUnregister.
func (s *socketVFS2) EventUnregister(e *waiter.Entry) {
s.socketOpsCommon.EventUnregister(e)
}
// Ioctl implements vfs.FileDescriptionImpl.
func (s *socketVFS2) Ioctl(ctx context.Context, uio usermem.IO, args arch.SyscallArguments) (uintptr, error) {
return ioctl(ctx, s.fd, uio, args)
}
// PRead implements vfs.FileDescriptionImpl.
func (s *socketVFS2) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
return 0, syserror.ESPIPE
}
// Read implements vfs.FileDescriptionImpl.
func (s *socketVFS2) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
// All flags other than RWF_NOWAIT should be ignored.
// TODO(gvisor.dev/issue/2601): Support RWF_NOWAIT.
if opts.Flags != 0 {
return 0, syserror.EOPNOTSUPP
}
reader := hostfd.GetReadWriterAt(int32(s.fd), -1, opts.Flags)
n, err := dst.CopyOutFrom(ctx, reader)
hostfd.PutReadWriterAt(reader)
return int64(n), err
}
// PWrite implements vfs.FileDescriptionImpl.
func (s *socketVFS2) PWrite(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
return 0, syserror.ESPIPE
}
// Write implements vfs.FileDescriptionImpl.
func (s *socketVFS2) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
// All flags other than RWF_NOWAIT should be ignored.
// TODO(gvisor.dev/issue/2601): Support RWF_NOWAIT.
if opts.Flags != 0 {
return 0, syserror.EOPNOTSUPP
}
writer := hostfd.GetReadWriterAt(int32(s.fd), -1, opts.Flags)
n, err := src.CopyInTo(ctx, writer)
hostfd.PutReadWriterAt(writer)
return int64(n), err
}
type socketProviderVFS2 struct {
family int
}
// Socket implements socket.ProviderVFS2.Socket.
func (p *socketProviderVFS2) Socket(t *kernel.Task, stypeflags linux.SockType, protocol int) (*vfs.FileDescription, *syserr.Error) {
// Check that we are using the host network stack.
stack := t.NetworkContext()
if stack == nil {
return nil, nil
}
if _, ok := stack.(*Stack); !ok {
return nil, nil
}
// Only accept TCP and UDP.
stype := stypeflags & linux.SOCK_TYPE_MASK
switch stype {
case syscall.SOCK_STREAM:
switch protocol {
case 0, syscall.IPPROTO_TCP:
// ok
default:
return nil, nil
}
case syscall.SOCK_DGRAM:
switch protocol {
case 0, syscall.IPPROTO_UDP:
// ok
default:
return nil, nil
}
default:
return nil, nil
}
// Conservatively ignore all flags specified by the application and add
// SOCK_NONBLOCK since socketOperations requires it. Pass a protocol of 0
// to simplify the syscall filters, since 0 and IPPROTO_* are equivalent.
fd, err := syscall.Socket(p.family, int(stype)|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, 0)
if err != nil {
return nil, syserr.FromError(err)
}
return newVFS2Socket(t, p.family, stype, protocol, fd, uint32(stypeflags&syscall.SOCK_NONBLOCK))
}
// Pair implements socket.Provider.Pair.
func (p *socketProviderVFS2) Pair(t *kernel.Task, stype linux.SockType, protocol int) (*vfs.FileDescription, *vfs.FileDescription, *syserr.Error) {
// Not supported by AF_INET/AF_INET6.
return nil, nil, nil
}
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