diff options
Diffstat (limited to 'pkg/waiter')
| -rw-r--r-- | pkg/waiter/fdnotifier/BUILD | 14 | ||||
| -rw-r--r-- | pkg/waiter/fdnotifier/fdnotifier.go | 200 | ||||
| -rw-r--r-- | pkg/waiter/fdnotifier/poll_unsafe.go | 74 |
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 := ¬ifier{ - 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 -} |