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authorgVisor bot <gvisor-bot@google.com>2020-05-07 19:46:45 +0000
committergVisor bot <gvisor-bot@google.com>2020-05-07 19:46:45 +0000
commita5732c2feea817d08a240baf1b78c850431cd5bd (patch)
tree17e3ed36a6ad817f357047378160c9ea8c4ab93d /pkg/sentry/vfs
parentca611916a7c44059975f273183b1fb25bfe656ae (diff)
parentd0b1d0233dc8a8ac837d534cd0664eabb9dd0a71 (diff)
Merge release-20200422.0-49-gd0b1d02 (automated)
Diffstat (limited to 'pkg/sentry/vfs')
-rwxr-xr-xpkg/sentry/vfs/eventfd.go282
-rwxr-xr-xpkg/sentry/vfs/timerfd.go141
2 files changed, 0 insertions, 423 deletions
diff --git a/pkg/sentry/vfs/eventfd.go b/pkg/sentry/vfs/eventfd.go
deleted file mode 100755
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/timerfd.go b/pkg/sentry/vfs/timerfd.go
deleted file mode 100755
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() {}