Add plumbing for file locks in VFS2.

Updates #1480

PiperOrigin-RevId: 292180192

3 files changed, 42 insertions, 1 deletions

diff --git a/pkg/sentry/vfs/BUILD b/pkg/sentry/vfs/BUILD
index ced9d07b1..14b39eb9d 100644
--- a/pkg/sentry/vfs/BUILD
+++ b/pkg/sentry/vfs/BUILD
@@ -44,6 +44,7 @@ go_library(
         "//pkg/context",
         "//pkg/fspath",
         "//pkg/sentry/arch",
+        "//pkg/sentry/fs/lock",
         "//pkg/sentry/kernel/auth",
         "//pkg/sentry/memmap",
         "//pkg/sync",
diff --git a/pkg/sentry/vfs/file_description.go b/pkg/sentry/vfs/file_description.go
index badacb55e..5bac660c7 100644
--- a/pkg/sentry/vfs/file_description.go
+++ b/pkg/sentry/vfs/file_description.go
@@ -20,6 +20,7 @@ import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
+	"gvisor.dev/gvisor/pkg/sentry/fs/lock"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sync"
@@ -393,7 +394,25 @@ type FileDescriptionImpl interface {
 	// Removexattr removes the given extended attribute from the file.
 	Removexattr(ctx context.Context, name string) error
 
-	// TODO: file locking
+	// LockBSD tries to acquire a BSD-style advisory file lock.
+	//
+	// TODO(gvisor.dev/issue/1480): BSD-style file locking
+	LockBSD(ctx context.Context, uid lock.UniqueID, t lock.LockType, block lock.Blocker) error
+
+	// LockBSD releases a BSD-style advisory file lock.
+	//
+	// TODO(gvisor.dev/issue/1480): BSD-style file locking
+	UnlockBSD(ctx context.Context, uid lock.UniqueID) error
+
+	// LockPOSIX tries to acquire a POSIX-style advisory file lock.
+	//
+	// TODO(gvisor.dev/issue/1480): POSIX-style file locking
+	LockPOSIX(ctx context.Context, uid lock.UniqueID, t lock.LockType, rng lock.LockRange, block lock.Blocker) error
+
+	// UnlockPOSIX releases a POSIX-style advisory file lock.
+	//
+	// TODO(gvisor.dev/issue/1480): POSIX-style file locking
+	UnlockPOSIX(ctx context.Context, uid lock.UniqueID, rng lock.LockRange) error
 }
 
 // Dirent holds the information contained in struct linux_dirent64.
diff --git a/pkg/sentry/vfs/file_description_impl_util.go b/pkg/sentry/vfs/file_description_impl_util.go
index a4900c170..c2a52ec1b 100644
--- a/pkg/sentry/vfs/file_description_impl_util.go
+++ b/pkg/sentry/vfs/file_description_impl_util.go
@@ -21,6 +21,7 @@ import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
+	"gvisor.dev/gvisor/pkg/sentry/fs/lock"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
@@ -152,6 +153,26 @@ func (FileDescriptionDefaultImpl) Removexattr(ctx context.Context, name string)
 	return syserror.ENOTSUP
 }
 
+// LockBSD implements FileDescriptionImpl.LockBSD.
+func (FileDescriptionDefaultImpl) LockBSD(ctx context.Context, uid lock.UniqueID, t lock.LockType, block lock.Blocker) error {
+	return syserror.EBADF
+}
+
+// UnlockBSD implements FileDescriptionImpl.UnlockBSD.
+func (FileDescriptionDefaultImpl) UnlockBSD(ctx context.Context, uid lock.UniqueID) error {
+	return syserror.EBADF
+}
+
+// LockPOSIX implements FileDescriptionImpl.LockPOSIX.
+func (FileDescriptionDefaultImpl) LockPOSIX(ctx context.Context, uid lock.UniqueID, t lock.LockType, rng lock.LockRange, block lock.Blocker) error {
+	return syserror.EBADF
+}
+
+// UnlockPOSIX implements FileDescriptionImpl.UnlockPOSIX.
+func (FileDescriptionDefaultImpl) UnlockPOSIX(ctx context.Context, uid lock.UniqueID, rng lock.LockRange) error {
+	return syserror.EBADF
+}
+
 // DirectoryFileDescriptionDefaultImpl may be embedded by implementations of
 // FileDescriptionImpl that always represent directories to obtain
 // implementations of non-directory I/O methods that return EISDIR.