diff options
author | Jamie Liu <jamieliu@google.com> | 2020-07-06 22:54:01 -0700 |
---|---|---|
committer | gVisor bot <gvisor-bot@google.com> | 2020-07-06 22:55:48 -0700 |
commit | e227450dc1ec1ef07b9a6a5983ce2f2e0dec22b1 (patch) | |
tree | fdbbae656066f108a85c165934bf509b7f4271ca | |
parent | 937912a4847cb1fd2acb79c0dd8fbc4b27695156 (diff) |
Call fdnotifier.UpdateFD() from fsimpl/gofer.specialFileFD.
The fdnotifier package provides an API to a thread that continually epolls
arbitrary host FDs. The set of events polled for each host FD is (intended to
be) all events for which a waiter.Entry has expressed interest, as returned by
waiter.Queue.Events() for the waiter.Queue registered to the given host FD.
When the set of events changes (due to a change in the set of registered
waiter.Entries), the mutator must call fdnotifier.UpdateFD() to recalculate the
new event set and propagate it to the epoll FD.
PiperOrigin-RevId: 319924719
-rw-r--r-- | pkg/sentry/fsimpl/gofer/special_file.go | 30 |
1 files changed, 16 insertions, 14 deletions
diff --git a/pkg/sentry/fsimpl/gofer/special_file.go b/pkg/sentry/fsimpl/gofer/special_file.go index 3c4e7e2e4..c1e6b13e5 100644 --- a/pkg/sentry/fsimpl/gofer/special_file.go +++ b/pkg/sentry/fsimpl/gofer/special_file.go @@ -41,10 +41,10 @@ type specialFileFD struct { // file offset is significant, i.e. a regular file. seekable is immutable. seekable bool - // mayBlock is true if this file description represents a file for which - // queue may send I/O readiness events. mayBlock is immutable. - mayBlock bool - queue waiter.Queue + // haveQueue is true if this file description represents a file for which + // queue may send I/O readiness events. haveQueue is immutable. + haveQueue bool + queue waiter.Queue // If seekable is true, off is the file offset. off is protected by mu. mu sync.Mutex @@ -54,14 +54,14 @@ type specialFileFD struct { func newSpecialFileFD(h handle, mnt *vfs.Mount, d *dentry, locks *vfs.FileLocks, flags uint32) (*specialFileFD, error) { ftype := d.fileType() seekable := ftype == linux.S_IFREG - mayBlock := ftype == linux.S_IFIFO || ftype == linux.S_IFSOCK + haveQueue := (ftype == linux.S_IFIFO || ftype == linux.S_IFSOCK) && h.fd >= 0 fd := &specialFileFD{ - handle: h, - seekable: seekable, - mayBlock: mayBlock, + handle: h, + seekable: seekable, + haveQueue: haveQueue, } fd.LockFD.Init(locks) - if mayBlock && h.fd >= 0 { + if haveQueue { if err := fdnotifier.AddFD(h.fd, &fd.queue); err != nil { return nil, err } @@ -70,7 +70,7 @@ func newSpecialFileFD(h handle, mnt *vfs.Mount, d *dentry, locks *vfs.FileLocks, DenyPRead: !seekable, DenyPWrite: !seekable, }); err != nil { - if mayBlock && h.fd >= 0 { + if haveQueue { fdnotifier.RemoveFD(h.fd) } return nil, err @@ -80,7 +80,7 @@ func newSpecialFileFD(h handle, mnt *vfs.Mount, d *dentry, locks *vfs.FileLocks, // Release implements vfs.FileDescriptionImpl.Release. func (fd *specialFileFD) Release() { - if fd.mayBlock && fd.handle.fd >= 0 { + if fd.haveQueue { fdnotifier.RemoveFD(fd.handle.fd) } fd.handle.close(context.Background()) @@ -100,7 +100,7 @@ func (fd *specialFileFD) OnClose(ctx context.Context) error { // Readiness implements waiter.Waitable.Readiness. func (fd *specialFileFD) Readiness(mask waiter.EventMask) waiter.EventMask { - if fd.mayBlock { + if fd.haveQueue { return fdnotifier.NonBlockingPoll(fd.handle.fd, mask) } return fd.fileDescription.Readiness(mask) @@ -108,8 +108,9 @@ func (fd *specialFileFD) Readiness(mask waiter.EventMask) waiter.EventMask { // EventRegister implements waiter.Waitable.EventRegister. func (fd *specialFileFD) EventRegister(e *waiter.Entry, mask waiter.EventMask) { - if fd.mayBlock { + if fd.haveQueue { fd.queue.EventRegister(e, mask) + fdnotifier.UpdateFD(fd.handle.fd) return } fd.fileDescription.EventRegister(e, mask) @@ -117,8 +118,9 @@ func (fd *specialFileFD) EventRegister(e *waiter.Entry, mask waiter.EventMask) { // EventUnregister implements waiter.Waitable.EventUnregister. func (fd *specialFileFD) EventUnregister(e *waiter.Entry) { - if fd.mayBlock { + if fd.haveQueue { fd.queue.EventUnregister(e) + fdnotifier.UpdateFD(fd.handle.fd) return } fd.fileDescription.EventUnregister(e) |