Implement POSIX locks

- Change FileDescriptionImpl Lock/UnlockPOSIX signature to
  take {start,length,whence}, so the correct offset can be
  calculated in the implementations.
- Create PosixLocker interface to make it possible to share
  the same locking code from different implementations.

Closes #1480

PiperOrigin-RevId: 316910286

1 files changed, 12 insertions, 2 deletions

diff --git a/pkg/sentry/fsimpl/host/host.go b/pkg/sentry/fsimpl/host/host.go
index 5ec5100b8..7906242c9 100644
--- a/pkg/sentry/fsimpl/host/host.go
+++ b/pkg/sentry/fsimpl/host/host.go
@@ -28,13 +28,13 @@ import (
 	"gvisor.dev/gvisor/pkg/fspath"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/refs"
+	fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock"
 	"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
 	"gvisor.dev/gvisor/pkg/sentry/hostfd"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	unixsocket "gvisor.dev/gvisor/pkg/sentry/socket/unix"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
-	"gvisor.dev/gvisor/pkg/sentry/vfs/lock"
 	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/usermem"
@@ -183,7 +183,7 @@ type inode struct {
 	kernfs.InodeNotDirectory
 	kernfs.InodeNotSymlink
 
-	locks lock.FileLocks
+	locks vfs.FileLocks
 
 	// When the reference count reaches zero, the host fd is closed.
 	refs.AtomicRefCount
@@ -718,3 +718,13 @@ func (f *fileDescription) EventUnregister(e *waiter.Entry) {
 func (f *fileDescription) Readiness(mask waiter.EventMask) waiter.EventMask {
 	return fdnotifier.NonBlockingPoll(int32(f.inode.hostFD), mask)
 }
+
+// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX.
+func (f *fileDescription) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error {
+	return f.Locks().LockPOSIX(ctx, &f.vfsfd, uid, t, start, length, whence, block)
+}
+
+// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX.
+func (f *fileDescription) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error {
+	return f.Locks().UnlockPOSIX(ctx, &f.vfsfd, uid, start, length, whence)
+}