Move fdnotifier package to reduce internal confusion.

PiperOrigin-RevId: 225632398
Change-Id: I909e7e2925aa369adc28e844c284d9a6108e85ce

3 files changed, 0 insertions, 288 deletions

diff --git a/pkg/waiter/fdnotifier/BUILD b/pkg/waiter/fdnotifier/BUILD
deleted file mode 100644
index af6baa303..000000000
--- a/pkg/waiter/fdnotifier/BUILD
+++ /dev/null
@@ -1,14 +0,0 @@
-load("//tools/go_stateify:defs.bzl", "go_library")
-
-package(licenses = ["notice"])  # Apache 2.0
-
-go_library(
-    name = "fdnotifier",
-    srcs = [
-        "fdnotifier.go",
-        "poll_unsafe.go",
-    ],
-    importpath = "gvisor.googlesource.com/gvisor/pkg/waiter/fdnotifier",
-    visibility = ["//:sandbox"],
-    deps = ["//pkg/waiter"],
-)
diff --git a/pkg/waiter/fdnotifier/fdnotifier.go b/pkg/waiter/fdnotifier/fdnotifier.go
deleted file mode 100644
index 624b1a0c5..000000000
--- a/pkg/waiter/fdnotifier/fdnotifier.go
+++ /dev/null
@@ -1,200 +0,0 @@
-// Copyright 2018 Google LLC
-//
-// 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 fdnotifier contains an adapter that translates IO events (e.g., a
-// file became readable/writable) from native FDs to the notifications in the
-// waiter package. It uses epoll in edge-triggered mode to receive notifications
-// for registered FDs.
-package fdnotifier
-
-import (
-	"fmt"
-	"sync"
-	"syscall"
-
-	"gvisor.googlesource.com/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 {
-	// epFD is the epoll file descriptor used to register for io
-	// notifications.
-	epFD int
-
-	// mu protects fdMap.
-	mu sync.Mutex
-
-	// fdMap maps file descriptors to their notification queues and waiting
-	// status.
-	fdMap map[int32]*fdInfo
-}
-
-// newNotifier creates a new notifier object.
-func newNotifier() (*notifier, error) {
-	epfd, err := syscall.EpollCreate1(0)
-	if err != nil {
-		return nil, err
-	}
-
-	w := &notifier{
-		epFD:  epfd,
-		fdMap: make(map[int32]*fdInfo),
-	}
-
-	go w.waitAndNotify() // S/R-SAFE: no waiter exists during save / load.
-
-	return w, nil
-}
-
-// waitFD waits on mask for fd. The fdMap mutex must be hold.
-func (n *notifier) waitFD(fd int32, fi *fdInfo, mask waiter.EventMask) error {
-	if !fi.waiting && mask == 0 {
-		return nil
-	}
-
-	e := syscall.EpollEvent{
-		Events: uint32(mask) | -syscall.EPOLLET,
-		Fd:     fd,
-	}
-
-	switch {
-	case !fi.waiting && mask != 0:
-		if err := syscall.EpollCtl(n.epFD, syscall.EPOLL_CTL_ADD, int(fd), &e); err != nil {
-			return err
-		}
-		fi.waiting = true
-	case fi.waiting && mask == 0:
-		syscall.EpollCtl(n.epFD, syscall.EPOLL_CTL_DEL, int(fd), nil)
-		fi.waiting = false
-	case fi.waiting && mask != 0:
-		if err := syscall.EpollCtl(n.epFD, syscall.EPOLL_CTL_MOD, int(fd), &e); err != nil {
-			return err
-		}
-	}
-
-	return nil
-}
-
-// addFD adds an FD to the list of FDs observed by n.
-func (n *notifier) addFD(fd int32, 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 %v 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 int32) 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 int32) {
-	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 int32) bool {
-	n.mu.Lock()
-	defer n.mu.Unlock()
-
-	_, ok := n.fdMap[fd]
-	return ok
-}
-
-// waitAndNotify run is its own goroutine and 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 {
-	e := make([]syscall.EpollEvent, 100)
-	for {
-		v, err := epollWait(n.epFD, e, -1)
-		if err == syscall.EINTR {
-			continue
-		}
-
-		if err != nil {
-			return err
-		}
-
-		n.mu.Lock()
-		for i := 0; i < v; i++ {
-			if fi, ok := n.fdMap[e[i].Fd]; ok {
-				fi.queue.Notify(waiter.EventMask(e[i].Events))
-			}
-		}
-		n.mu.Unlock()
-	}
-}
-
-var shared struct {
-	notifier *notifier
-	once     sync.Once
-	initErr  error
-}
-
-// AddFD adds an FD to the list of observed FDs.
-func AddFD(fd int32, queue *waiter.Queue) error {
-	shared.once.Do(func() {
-		shared.notifier, shared.initErr = newNotifier()
-	})
-
-	if shared.initErr != nil {
-		return shared.initErr
-	}
-
-	shared.notifier.addFD(fd, queue)
-	return nil
-}
-
-// UpdateFD updates the set of events the fd needs to be notified on.
-func UpdateFD(fd int32) error {
-	return shared.notifier.updateFD(fd)
-}
-
-// RemoveFD removes an FD from the list of observed FDs.
-func RemoveFD(fd int32) {
-	shared.notifier.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 HasFD(fd int32) bool {
-	return shared.notifier.hasFD(fd)
-}
diff --git a/pkg/waiter/fdnotifier/poll_unsafe.go b/pkg/waiter/fdnotifier/poll_unsafe.go
deleted file mode 100644
index 8459d4c74..000000000
--- a/pkg/waiter/fdnotifier/poll_unsafe.go
+++ /dev/null
@@ -1,74 +0,0 @@
-// Copyright 2018 Google LLC
-//
-// 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 fdnotifier
-
-import (
-	"syscall"
-	"unsafe"
-
-	"gvisor.googlesource.com/gvisor/pkg/waiter"
-)
-
-// NonBlockingPoll polls the given FD in non-blocking fashion. It is used just
-// to query the FD's current state.
-func NonBlockingPoll(fd int32, mask waiter.EventMask) waiter.EventMask {
-	e := struct {
-		fd      int32
-		events  int16
-		revents int16
-	}{
-		fd:     fd,
-		events: int16(mask),
-	}
-
-	for {
-		n, _, err := syscall.RawSyscall(syscall.SYS_POLL, uintptr(unsafe.Pointer(&e)), 1, 0)
-		// Interrupted by signal, try again.
-		if err == syscall.EINTR {
-			continue
-		}
-		// If an error occur we'll conservatively say the FD is ready for
-		// whatever is being checked.
-		if err != 0 {
-			return mask
-		}
-
-		// If no FDs were returned, it wasn't ready for anything.
-		if n == 0 {
-			return 0
-		}
-
-		// Otherwise we got the ready events in the revents field.
-		return waiter.EventMask(e.revents)
-	}
-}
-
-// epollWait performs a blocking wait on epfd.
-//
-// Preconditions:
-//  * len(events) > 0
-func epollWait(epfd int, events []syscall.EpollEvent, msec int) (int, error) {
-	if len(events) == 0 {
-		panic("Empty events passed to EpollWait")
-	}
-
-	// We actually use epoll_pwait with NULL sigmask instead of epoll_wait
-	// since that is what the Go >= 1.11 runtime prefers.
-	r, _, e := syscall.Syscall6(syscall.SYS_EPOLL_PWAIT, uintptr(epfd), uintptr(unsafe.Pointer(&events[0])), uintptr(len(events)), uintptr(msec), 0, 0)
-	if e != 0 {
-		return 0, e
-	}
-	return int(r), nil
-}