diff options
author | Andrei Vagin <avagin@google.com> | 2019-05-13 10:37:24 -0700 |
---|---|---|
committer | Shentubot <shentubot@google.com> | 2019-05-13 10:38:27 -0700 |
commit | ec248daf29974c3c3f99f4c110059e2c4e50fbe0 (patch) | |
tree | d575108aed04e98db4cb6de6f037fb1f967f4f17 /pkg/fdnotifier | |
parent | 9f2b12c624a4a07c6662d1a5f1bced28b6eb86da (diff) |
gvisor/hostnet: restart epoll_wait after epoll_ctl
Otherwise changes of epoll_ctl will not have affect.
PiperOrigin-RevId: 247964961
Change-Id: I9fbb35c44766421af45d9ed53760e0c324d80d99
Diffstat (limited to 'pkg/fdnotifier')
-rw-r--r-- | pkg/fdnotifier/fdnotifier.go | 30 | ||||
-rw-r--r-- | pkg/fdnotifier/poll_unsafe.go | 25 |
2 files changed, 53 insertions, 2 deletions
diff --git a/pkg/fdnotifier/fdnotifier.go b/pkg/fdnotifier/fdnotifier.go index f0b028b0b..731fa4dad 100644 --- a/pkg/fdnotifier/fdnotifier.go +++ b/pkg/fdnotifier/fdnotifier.go @@ -40,6 +40,10 @@ type notifier struct { // notifications. epFD int + // eventFD is used to restart epoll_wait in waitAndNotify after + // reconfiguring epFD. + eventFD int + // mu protects fdMap. mu sync.Mutex @@ -55,9 +59,20 @@ func newNotifier() (*notifier, error) { return nil, err } + eventFD, err := eventFDCreate() + if err != nil { + syscall.Close(epfd) + return nil, err + } + w := ¬ifier{ - epFD: epfd, - fdMap: make(map[int32]*fdInfo), + epFD: epfd, + eventFD: eventFD, + fdMap: make(map[int32]*fdInfo), + } + + if err := w.waitFD(int32(w.eventFD), &fdInfo{}, waiter.EventIn); err != nil { + return nil, err } go w.waitAndNotify() // S/R-SAFE: no waiter exists during save / load. @@ -91,6 +106,11 @@ func (n *notifier) waitFD(fd int32, fi *fdInfo, mask waiter.EventMask) error { } } + // Restart epoll_wait in waitAndNotify. + if err := eventFDWrite(n.eventFD, 1); err != nil { + return err + } + return nil } @@ -156,6 +176,12 @@ func (n *notifier) waitAndNotify() error { n.mu.Lock() for i := 0; i < v; i++ { + if e[i].Fd == int32(n.eventFD) { + if _, err := eventFDRead(n.eventFD); err != nil { + return err + } + continue + } if fi, ok := n.fdMap[e[i].Fd]; ok { fi.queue.Notify(waiter.EventMaskFromLinux(e[i].Events)) } diff --git a/pkg/fdnotifier/poll_unsafe.go b/pkg/fdnotifier/poll_unsafe.go index bc5e0ac44..882e9010d 100644 --- a/pkg/fdnotifier/poll_unsafe.go +++ b/pkg/fdnotifier/poll_unsafe.go @@ -74,3 +74,28 @@ func epollWait(epfd int, events []syscall.EpollEvent, msec int) (int, error) { } return int(r), nil } + +func eventFDCreate() (int, error) { + eventFD, _, err := syscall.RawSyscall(syscall.SYS_EVENTFD2, 0, 0, 0) + if err != 0 { + return -1, err + } + return int(eventFD), nil +} + +func eventFDWrite(eventFD int, v uint64) error { + if _, _, err := syscall.RawSyscall(syscall.SYS_WRITE, uintptr(eventFD), uintptr(unsafe.Pointer(&v)), 8); err != 0 { + return err + } + + return nil +} + +func eventFDRead(eventFD int) (uint64, error) { + var v uint64 + if _, _, err := syscall.RawSyscall(syscall.SYS_READ, uintptr(eventFD), uintptr(unsafe.Pointer(&v)), 8); err != 0 { + return 0, err + } + + return v, nil +} |