Move pkg/sentry/vfs/{eventfd,timerfd} to new packages in pkg/sentry/fsimpl.

They don't depend on anything in VFS2, so they should be their own packages.

PiperOrigin-RevId: 310416807

4 files changed, 0 insertions, 523 deletions

diff --git a/pkg/sentry/vfs/BUILD b/pkg/sentry/vfs/BUILD
index 86046dd99..94d69c1cc 100644
--- a/pkg/sentry/vfs/BUILD
+++ b/pkg/sentry/vfs/BUILD
@@ -25,7 +25,6 @@ go_library(
         "device.go",
         "epoll.go",
         "epoll_interest_list.go",
-        "eventfd.go",
         "file_description.go",
         "file_description_impl_util.go",
         "filesystem.go",
@@ -37,7 +36,6 @@ go_library(
         "pathname.go",
         "permissions.go",
         "resolving_path.go",
-        "timerfd.go",
         "vfs.go",
     ],
     visibility = ["//pkg/sentry:internal"],
@@ -71,7 +69,6 @@ go_test(
     name = "vfs_test",
     size = "small",
     srcs = [
-        "eventfd_test.go",
         "file_description_impl_util_test.go",
         "mount_test.go",
     ],
@@ -83,6 +80,5 @@ go_test(
         "//pkg/sync",
         "//pkg/syserror",
         "//pkg/usermem",
-        "//pkg/waiter",
     ],
 )
diff --git a/pkg/sentry/vfs/eventfd.go b/pkg/sentry/vfs/eventfd.go
deleted file mode 100644
index f39dacacf..000000000
--- a/pkg/sentry/vfs/eventfd.go
+++ /dev/null
@@ -1,282 +0,0 @@
-// 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 vfs
-
-import (
-	"math"
-	"sync"
-	"syscall"
-
-	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/context"
-	"gvisor.dev/gvisor/pkg/fdnotifier"
-	"gvisor.dev/gvisor/pkg/log"
-	"gvisor.dev/gvisor/pkg/syserror"
-	"gvisor.dev/gvisor/pkg/usermem"
-	"gvisor.dev/gvisor/pkg/waiter"
-)
-
-// EventFileDescription implements FileDescriptionImpl for file-based event
-// notification (eventfd). Eventfds are usually internal to the Sentry but in
-// certain situations they may be converted into a host-backed eventfd.
-type EventFileDescription struct {
-	vfsfd FileDescription
-	FileDescriptionDefaultImpl
-	DentryMetadataFileDescriptionImpl
-
-	// queue is used to notify interested parties when the event object
-	// becomes readable or writable.
-	queue waiter.Queue `state:"zerovalue"`
-
-	// mu protects the fields below.
-	mu sync.Mutex `state:"nosave"`
-
-	// val is the current value of the event counter.
-	val uint64
-
-	// semMode specifies whether the event is in "semaphore" mode.
-	semMode bool
-
-	// hostfd indicates whether this eventfd is passed through to the host.
-	hostfd int
-}
-
-var _ FileDescriptionImpl = (*EventFileDescription)(nil)
-
-// NewEventFD creates a new event fd.
-func (vfs *VirtualFilesystem) NewEventFD(initVal uint64, semMode bool, flags uint32) (*FileDescription, error) {
-	vd := vfs.NewAnonVirtualDentry("[eventfd]")
-	defer vd.DecRef()
-	efd := &EventFileDescription{
-		val:     initVal,
-		semMode: semMode,
-		hostfd:  -1,
-	}
-	if err := efd.vfsfd.Init(efd, flags, vd.Mount(), vd.Dentry(), &FileDescriptionOptions{
-		UseDentryMetadata: true,
-		DenyPRead:         true,
-		DenyPWrite:        true,
-	}); err != nil {
-		return nil, err
-	}
-	return &efd.vfsfd, nil
-}
-
-// HostFD returns the host eventfd associated with this event.
-func (efd *EventFileDescription) HostFD() (int, error) {
-	efd.mu.Lock()
-	defer efd.mu.Unlock()
-	if efd.hostfd >= 0 {
-		return efd.hostfd, nil
-	}
-
-	flags := linux.EFD_NONBLOCK
-	if efd.semMode {
-		flags |= linux.EFD_SEMAPHORE
-	}
-
-	fd, _, errno := syscall.Syscall(syscall.SYS_EVENTFD2, uintptr(efd.val), uintptr(flags), 0)
-	if errno != 0 {
-		return -1, errno
-	}
-
-	if err := fdnotifier.AddFD(int32(fd), &efd.queue); err != nil {
-		if closeErr := syscall.Close(int(fd)); closeErr != nil {
-			log.Warningf("close(%d) eventfd failed: %v", fd, closeErr)
-		}
-		return -1, err
-	}
-
-	efd.hostfd = int(fd)
-	return efd.hostfd, nil
-}
-
-// Release implements FileDescriptionImpl.Release()
-func (efd *EventFileDescription) Release() {
-	efd.mu.Lock()
-	defer efd.mu.Unlock()
-	if efd.hostfd >= 0 {
-		fdnotifier.RemoveFD(int32(efd.hostfd))
-		if closeErr := syscall.Close(int(efd.hostfd)); closeErr != nil {
-			log.Warningf("close(%d) eventfd failed: %v", efd.hostfd, closeErr)
-		}
-		efd.hostfd = -1
-	}
-}
-
-// Read implements FileDescriptionImpl.Read.
-func (efd *EventFileDescription) Read(ctx context.Context, dst usermem.IOSequence, _ ReadOptions) (int64, error) {
-	if dst.NumBytes() < 8 {
-		return 0, syscall.EINVAL
-	}
-	if err := efd.read(ctx, dst); err != nil {
-		return 0, err
-	}
-	return 8, nil
-}
-
-// Write implements FileDescriptionImpl.Write.
-func (efd *EventFileDescription) Write(ctx context.Context, src usermem.IOSequence, _ WriteOptions) (int64, error) {
-	if src.NumBytes() < 8 {
-		return 0, syscall.EINVAL
-	}
-	if err := efd.write(ctx, src); err != nil {
-		return 0, err
-	}
-	return 8, nil
-}
-
-// Preconditions: Must be called with efd.mu locked.
-func (efd *EventFileDescription) hostReadLocked(ctx context.Context, dst usermem.IOSequence) error {
-	var buf [8]byte
-	if _, err := syscall.Read(efd.hostfd, buf[:]); err != nil {
-		if err == syscall.EWOULDBLOCK {
-			return syserror.ErrWouldBlock
-		}
-		return err
-	}
-	_, err := dst.CopyOut(ctx, buf[:])
-	return err
-}
-
-func (efd *EventFileDescription) read(ctx context.Context, dst usermem.IOSequence) error {
-	efd.mu.Lock()
-	if efd.hostfd >= 0 {
-		defer efd.mu.Unlock()
-		return efd.hostReadLocked(ctx, dst)
-	}
-
-	// We can't complete the read if the value is currently zero.
-	if efd.val == 0 {
-		efd.mu.Unlock()
-		return syserror.ErrWouldBlock
-	}
-
-	// Update the value based on the mode the event is operating in.
-	var val uint64
-	if efd.semMode {
-		val = 1
-		// Consistent with Linux, this is done even if writing to memory fails.
-		efd.val--
-	} else {
-		val = efd.val
-		efd.val = 0
-	}
-
-	efd.mu.Unlock()
-
-	// Notify writers. We do this even if we were already writable because
-	// it is possible that a writer is waiting to write the maximum value
-	// to the event.
-	efd.queue.Notify(waiter.EventOut)
-
-	var buf [8]byte
-	usermem.ByteOrder.PutUint64(buf[:], val)
-	_, err := dst.CopyOut(ctx, buf[:])
-	return err
-}
-
-// Preconditions: Must be called with efd.mu locked.
-func (efd *EventFileDescription) hostWriteLocked(val uint64) error {
-	var buf [8]byte
-	usermem.ByteOrder.PutUint64(buf[:], val)
-	_, err := syscall.Write(efd.hostfd, buf[:])
-	if err == syscall.EWOULDBLOCK {
-		return syserror.ErrWouldBlock
-	}
-	return err
-}
-
-func (efd *EventFileDescription) write(ctx context.Context, src usermem.IOSequence) error {
-	var buf [8]byte
-	if _, err := src.CopyIn(ctx, buf[:]); err != nil {
-		return err
-	}
-	val := usermem.ByteOrder.Uint64(buf[:])
-
-	return efd.Signal(val)
-}
-
-// Signal is an internal function to signal the event fd.
-func (efd *EventFileDescription) Signal(val uint64) error {
-	if val == math.MaxUint64 {
-		return syscall.EINVAL
-	}
-
-	efd.mu.Lock()
-
-	if efd.hostfd >= 0 {
-		defer efd.mu.Unlock()
-		return efd.hostWriteLocked(val)
-	}
-
-	// We only allow writes that won't cause the value to go over the max
-	// uint64 minus 1.
-	if val > math.MaxUint64-1-efd.val {
-		efd.mu.Unlock()
-		return syserror.ErrWouldBlock
-	}
-
-	efd.val += val
-	efd.mu.Unlock()
-
-	// Always trigger a notification.
-	efd.queue.Notify(waiter.EventIn)
-
-	return nil
-}
-
-// Readiness implements waiter.Waitable.Readiness.
-func (efd *EventFileDescription) Readiness(mask waiter.EventMask) waiter.EventMask {
-	efd.mu.Lock()
-	defer efd.mu.Unlock()
-
-	if efd.hostfd >= 0 {
-		return fdnotifier.NonBlockingPoll(int32(efd.hostfd), mask)
-	}
-
-	ready := waiter.EventMask(0)
-	if efd.val > 0 {
-		ready |= waiter.EventIn
-	}
-
-	if efd.val < math.MaxUint64-1 {
-		ready |= waiter.EventOut
-	}
-
-	return mask & ready
-}
-
-// EventRegister implements waiter.Waitable.EventRegister.
-func (efd *EventFileDescription) EventRegister(entry *waiter.Entry, mask waiter.EventMask) {
-	efd.queue.EventRegister(entry, mask)
-
-	efd.mu.Lock()
-	defer efd.mu.Unlock()
-	if efd.hostfd >= 0 {
-		fdnotifier.UpdateFD(int32(efd.hostfd))
-	}
-}
-
-// EventUnregister implements waiter.Waitable.EventUnregister.
-func (efd *EventFileDescription) EventUnregister(entry *waiter.Entry) {
-	efd.queue.EventUnregister(entry)
-
-	efd.mu.Lock()
-	defer efd.mu.Unlock()
-	if efd.hostfd >= 0 {
-		fdnotifier.UpdateFD(int32(efd.hostfd))
-	}
-}
diff --git a/pkg/sentry/vfs/eventfd_test.go b/pkg/sentry/vfs/eventfd_test.go
deleted file mode 100644
index 2dff2d10b..000000000
--- a/pkg/sentry/vfs/eventfd_test.go
+++ /dev/null
@@ -1,96 +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 vfs
-
-import (
-	"testing"
-
-	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/sentry/contexttest"
-	"gvisor.dev/gvisor/pkg/usermem"
-	"gvisor.dev/gvisor/pkg/waiter"
-)
-
-func TestEventFD(t *testing.T) {
-	initVals := []uint64{
-		0,
-		// Using a non-zero initial value verifies that writing to an
-		// eventfd signals when the eventfd's counter was already
-		// non-zero.
-		343,
-	}
-
-	for _, initVal := range initVals {
-		ctx := contexttest.Context(t)
-		vfsObj := &VirtualFilesystem{}
-		if err := vfsObj.Init(); err != nil {
-			t.Fatalf("VFS init: %v", err)
-		}
-
-		// Make a new eventfd that is writable.
-		eventfd, err := vfsObj.NewEventFD(initVal, false, linux.O_RDWR)
-		if err != nil {
-			t.Fatalf("NewEventFD failed: %v", err)
-		}
-		defer eventfd.DecRef()
-
-		// Register a callback for a write event.
-		w, ch := waiter.NewChannelEntry(nil)
-		eventfd.EventRegister(&w, waiter.EventIn)
-		defer eventfd.EventUnregister(&w)
-
-		data := []byte("00000124")
-		// Create and submit a write request.
-		n, err := eventfd.Write(ctx, usermem.BytesIOSequence(data), WriteOptions{})
-		if err != nil {
-			t.Fatal(err)
-		}
-		if n != 8 {
-			t.Errorf("eventfd.write wrote %d bytes, not full int64", n)
-		}
-
-		// Check if the callback fired due to the write event.
-		select {
-		case <-ch:
-		default:
-			t.Errorf("Didn't get notified of EventIn after write")
-		}
-	}
-}
-
-func TestEventFDStat(t *testing.T) {
-	ctx := contexttest.Context(t)
-	vfsObj := &VirtualFilesystem{}
-	if err := vfsObj.Init(); err != nil {
-		t.Fatalf("VFS init: %v", err)
-	}
-
-	// Make a new eventfd that is writable.
-	eventfd, err := vfsObj.NewEventFD(0, false, linux.O_RDWR)
-	if err != nil {
-		t.Fatalf("NewEventFD failed: %v", err)
-	}
-	defer eventfd.DecRef()
-
-	statx, err := eventfd.Stat(ctx, StatOptions{
-		Mask: linux.STATX_BASIC_STATS,
-	})
-	if err != nil {
-		t.Fatalf("eventfd.Stat failed: %v", err)
-	}
-	if statx.Size != 0 {
-		t.Errorf("eventfd size should be 0")
-	}
-}
diff --git a/pkg/sentry/vfs/timerfd.go b/pkg/sentry/vfs/timerfd.go
deleted file mode 100644
index cc536ceaf..000000000
--- a/pkg/sentry/vfs/timerfd.go
+++ /dev/null
@@ -1,141 +0,0 @@
-// 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 vfs
-
-import (
-	"sync/atomic"
-
-	"gvisor.dev/gvisor/pkg/context"
-	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
-	"gvisor.dev/gvisor/pkg/syserror"
-	"gvisor.dev/gvisor/pkg/usermem"
-	"gvisor.dev/gvisor/pkg/waiter"
-)
-
-// TimerFileDescription implements FileDescriptionImpl for timer fds. It also
-// implements ktime.TimerListener.
-type TimerFileDescription struct {
-	vfsfd FileDescription
-	FileDescriptionDefaultImpl
-	DentryMetadataFileDescriptionImpl
-
-	events waiter.Queue
-	timer  *ktime.Timer
-
-	// val is the number of timer expirations since the last successful
-	// call to PRead, or SetTime. val must be accessed using atomic memory
-	// operations.
-	val uint64
-}
-
-var _ FileDescriptionImpl = (*TimerFileDescription)(nil)
-var _ ktime.TimerListener = (*TimerFileDescription)(nil)
-
-// NewTimerFD returns a new timer fd.
-func (vfs *VirtualFilesystem) NewTimerFD(clock ktime.Clock, flags uint32) (*FileDescription, error) {
-	vd := vfs.NewAnonVirtualDentry("[timerfd]")
-	defer vd.DecRef()
-	tfd := &TimerFileDescription{}
-	tfd.timer = ktime.NewTimer(clock, tfd)
-	if err := tfd.vfsfd.Init(tfd, flags, vd.Mount(), vd.Dentry(), &FileDescriptionOptions{
-		UseDentryMetadata: true,
-		DenyPRead:         true,
-		DenyPWrite:        true,
-	}); err != nil {
-		return nil, err
-	}
-	return &tfd.vfsfd, nil
-}
-
-// Read implements FileDescriptionImpl.Read.
-func (tfd *TimerFileDescription) Read(ctx context.Context, dst usermem.IOSequence, opts ReadOptions) (int64, error) {
-	const sizeofUint64 = 8
-	if dst.NumBytes() < sizeofUint64 {
-		return 0, syserror.EINVAL
-	}
-	if val := atomic.SwapUint64(&tfd.val, 0); val != 0 {
-		var buf [sizeofUint64]byte
-		usermem.ByteOrder.PutUint64(buf[:], val)
-		if _, err := dst.CopyOut(ctx, buf[:]); err != nil {
-			// Linux does not undo consuming the number of
-			// expirations even if writing to userspace fails.
-			return 0, err
-		}
-		return sizeofUint64, nil
-	}
-	return 0, syserror.ErrWouldBlock
-}
-
-// Clock returns the timer fd's Clock.
-func (tfd *TimerFileDescription) Clock() ktime.Clock {
-	return tfd.timer.Clock()
-}
-
-// GetTime returns the associated Timer's setting and the time at which it was
-// observed.
-func (tfd *TimerFileDescription) GetTime() (ktime.Time, ktime.Setting) {
-	return tfd.timer.Get()
-}
-
-// SetTime atomically changes the associated Timer's setting, resets the number
-// of expirations to 0, and returns the previous setting and the time at which
-// it was observed.
-func (tfd *TimerFileDescription) SetTime(s ktime.Setting) (ktime.Time, ktime.Setting) {
-	return tfd.timer.SwapAnd(s, func() { atomic.StoreUint64(&tfd.val, 0) })
-}
-
-// Readiness implements waiter.Waitable.Readiness.
-func (tfd *TimerFileDescription) Readiness(mask waiter.EventMask) waiter.EventMask {
-	var ready waiter.EventMask
-	if atomic.LoadUint64(&tfd.val) != 0 {
-		ready |= waiter.EventIn
-	}
-	return ready
-}
-
-// EventRegister implements waiter.Waitable.EventRegister.
-func (tfd *TimerFileDescription) EventRegister(e *waiter.Entry, mask waiter.EventMask) {
-	tfd.events.EventRegister(e, mask)
-}
-
-// EventUnregister implements waiter.Waitable.EventUnregister.
-func (tfd *TimerFileDescription) EventUnregister(e *waiter.Entry) {
-	tfd.events.EventUnregister(e)
-}
-
-// PauseTimer pauses the associated Timer.
-func (tfd *TimerFileDescription) PauseTimer() {
-	tfd.timer.Pause()
-}
-
-// ResumeTimer resumes the associated Timer.
-func (tfd *TimerFileDescription) ResumeTimer() {
-	tfd.timer.Resume()
-}
-
-// Release implements FileDescriptionImpl.Release()
-func (tfd *TimerFileDescription) Release() {
-	tfd.timer.Destroy()
-}
-
-// Notify implements ktime.TimerListener.Notify.
-func (tfd *TimerFileDescription) Notify(exp uint64, setting ktime.Setting) (ktime.Setting, bool) {
-	atomic.AddUint64(&tfd.val, exp)
-	tfd.events.Notify(waiter.EventIn)
-	return ktime.Setting{}, false
-}
-
-// Destroy implements ktime.TimerListener.Destroy.
-func (tfd *TimerFileDescription) Destroy() {}