diff options
Diffstat (limited to 'pkg/sentry/socket/rpcinet/notifier/notifier.go')
-rw-r--r-- | pkg/sentry/socket/rpcinet/notifier/notifier.go | 231 |
1 files changed, 0 insertions, 231 deletions
diff --git a/pkg/sentry/socket/rpcinet/notifier/notifier.go b/pkg/sentry/socket/rpcinet/notifier/notifier.go deleted file mode 100644 index 7efe4301f..000000000 --- a/pkg/sentry/socket/rpcinet/notifier/notifier.go +++ /dev/null @@ -1,231 +0,0 @@ -// Copyright 2018 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 notifier implements an FD notifier implementation over RPC. -package notifier - -import ( - "fmt" - "sync" - "syscall" - - "golang.org/x/sys/unix" - "gvisor.dev/gvisor/pkg/sentry/socket/rpcinet/conn" - pb "gvisor.dev/gvisor/pkg/sentry/socket/rpcinet/syscall_rpc_go_proto" - "gvisor.dev/gvisor/pkg/waiter" -) - -type fdInfo struct { - queue *waiter.Queue - waiting bool -} - -// Notifier holds all the state necessary to issue notifications when IO events -// occur in the observed FDs. -type Notifier struct { - // rpcConn is the connection that is used for sending RPCs. - rpcConn *conn.RPCConnection - - // epFD is the epoll file descriptor used to register for io - // notifications. - epFD uint32 - - // mu protects fdMap. - mu sync.Mutex - - // fdMap maps file descriptors to their notification queues and waiting - // status. - fdMap map[uint32]*fdInfo -} - -// NewRPCNotifier creates a new notifier object. -func NewRPCNotifier(cn *conn.RPCConnection) (*Notifier, error) { - id, c := cn.NewRequest(pb.SyscallRequest{Args: &pb.SyscallRequest_EpollCreate1{&pb.EpollCreate1Request{}}}, false /* ignoreResult */) - <-c - - res := cn.Request(id).Result.(*pb.SyscallResponse_EpollCreate1).EpollCreate1.Result - if e, ok := res.(*pb.EpollCreate1Response_ErrorNumber); ok { - return nil, syscall.Errno(e.ErrorNumber) - } - - w := &Notifier{ - rpcConn: cn, - epFD: res.(*pb.EpollCreate1Response_Fd).Fd, - fdMap: make(map[uint32]*fdInfo), - } - - go w.waitAndNotify() // S/R-FIXME(b/77962828) - - return w, nil -} - -// waitFD waits on mask for fd. The fdMap mutex must be hold. -func (n *Notifier) waitFD(fd uint32, fi *fdInfo, mask waiter.EventMask) error { - if !fi.waiting && mask == 0 { - return nil - } - - e := pb.EpollEvent{ - Events: mask.ToLinux() | unix.EPOLLET, - Fd: fd, - } - - switch { - case !fi.waiting && mask != 0: - id, c := n.rpcConn.NewRequest(pb.SyscallRequest{Args: &pb.SyscallRequest_EpollCtl{&pb.EpollCtlRequest{Epfd: n.epFD, Op: syscall.EPOLL_CTL_ADD, Fd: fd, Event: &e}}}, false /* ignoreResult */) - <-c - - e := n.rpcConn.Request(id).Result.(*pb.SyscallResponse_EpollCtl).EpollCtl.ErrorNumber - if e != 0 { - return syscall.Errno(e) - } - - fi.waiting = true - case fi.waiting && mask == 0: - id, c := n.rpcConn.NewRequest(pb.SyscallRequest{Args: &pb.SyscallRequest_EpollCtl{&pb.EpollCtlRequest{Epfd: n.epFD, Op: syscall.EPOLL_CTL_DEL, Fd: fd}}}, false /* ignoreResult */) - <-c - n.rpcConn.Request(id) - - fi.waiting = false - case fi.waiting && mask != 0: - id, c := n.rpcConn.NewRequest(pb.SyscallRequest{Args: &pb.SyscallRequest_EpollCtl{&pb.EpollCtlRequest{Epfd: n.epFD, Op: syscall.EPOLL_CTL_MOD, Fd: fd, Event: &e}}}, false /* ignoreResult */) - <-c - - e := n.rpcConn.Request(id).Result.(*pb.SyscallResponse_EpollCtl).EpollCtl.ErrorNumber - if e != 0 { - return syscall.Errno(e) - } - } - - return nil -} - -// addFD adds an FD to the list of FDs observed by n. -func (n *Notifier) addFD(fd uint32, queue *waiter.Queue) { - n.mu.Lock() - defer n.mu.Unlock() - - // Panic if we're already notifying on this FD. - if _, ok := n.fdMap[fd]; ok { - panic(fmt.Sprintf("File descriptor %d added twice", fd)) - } - - // We have nothing to wait for at the moment. Just add it to the map. - n.fdMap[fd] = &fdInfo{queue: queue} -} - -// updateFD updates the set of events the FD needs to be notified on. -func (n *Notifier) updateFD(fd uint32) error { - n.mu.Lock() - defer n.mu.Unlock() - - if fi, ok := n.fdMap[fd]; ok { - return n.waitFD(fd, fi, fi.queue.Events()) - } - - return nil -} - -// RemoveFD removes an FD from the list of FDs observed by n. -func (n *Notifier) removeFD(fd uint32) { - n.mu.Lock() - defer n.mu.Unlock() - - // Remove from map, then from epoll object. - n.waitFD(fd, n.fdMap[fd], 0) - delete(n.fdMap, fd) -} - -// hasFD returns true if the FD is in the list of observed FDs. -func (n *Notifier) hasFD(fd uint32) bool { - n.mu.Lock() - defer n.mu.Unlock() - - _, ok := n.fdMap[fd] - return ok -} - -// waitAndNotify loops waiting for io event notifications from the epoll -// object. Once notifications arrive, they are dispatched to the -// registered queue. -func (n *Notifier) waitAndNotify() error { - for { - id, c := n.rpcConn.NewRequest(pb.SyscallRequest{Args: &pb.SyscallRequest_EpollWait{&pb.EpollWaitRequest{Fd: n.epFD, NumEvents: 100, Msec: -1}}}, false /* ignoreResult */) - <-c - - res := n.rpcConn.Request(id).Result.(*pb.SyscallResponse_EpollWait).EpollWait.Result - if e, ok := res.(*pb.EpollWaitResponse_ErrorNumber); ok { - err := syscall.Errno(e.ErrorNumber) - // NOTE(magi): I don't think epoll_wait can return EAGAIN but I'm being - // conseratively careful here since exiting the notification thread - // would be really bad. - if err == syscall.EINTR || err == syscall.EAGAIN { - continue - } - return err - } - - n.mu.Lock() - for _, e := range res.(*pb.EpollWaitResponse_Events).Events.Events { - if fi, ok := n.fdMap[e.Fd]; ok { - fi.queue.Notify(waiter.EventMaskFromLinux(e.Events)) - } - } - n.mu.Unlock() - } -} - -// AddFD adds an FD to the list of observed FDs. -func (n *Notifier) AddFD(fd uint32, queue *waiter.Queue) error { - n.addFD(fd, queue) - return nil -} - -// UpdateFD updates the set of events the FD needs to be notified on. -func (n *Notifier) UpdateFD(fd uint32) error { - return n.updateFD(fd) -} - -// RemoveFD removes an FD from the list of observed FDs. -func (n *Notifier) RemoveFD(fd uint32) { - n.removeFD(fd) -} - -// HasFD returns true if the FD is in the list of observed FDs. -// -// This should only be used by tests to assert that FDs are correctly -// registered. -func (n *Notifier) HasFD(fd uint32) bool { - return n.hasFD(fd) -} - -// NonBlockingPoll polls the given fd in non-blocking fashion. It is used just -// to query the FD's current state; this method will block on the RPC response -// although the syscall is non-blocking. -func (n *Notifier) NonBlockingPoll(fd uint32, mask waiter.EventMask) waiter.EventMask { - for { - id, c := n.rpcConn.NewRequest(pb.SyscallRequest{Args: &pb.SyscallRequest_Poll{&pb.PollRequest{Fd: fd, Events: mask.ToLinux()}}}, false /* ignoreResult */) - <-c - - res := n.rpcConn.Request(id).Result.(*pb.SyscallResponse_Poll).Poll.Result - if e, ok := res.(*pb.PollResponse_ErrorNumber); ok { - if syscall.Errno(e.ErrorNumber) == syscall.EINTR { - continue - } - return mask - } - - return waiter.EventMaskFromLinux(res.(*pb.PollResponse_Events).Events) - } -} |