Implement F_GETLK fcntl.

Fixes #5113.

PiperOrigin-RevId: 353313374

2 files changed, 11 insertions, 2 deletions

diff --git a/pkg/sentry/kernel/BUILD b/pkg/sentry/kernel/BUILD
index 0ee60569c..8a5b11d40 100644
--- a/pkg/sentry/kernel/BUILD
+++ b/pkg/sentry/kernel/BUILD
@@ -240,7 +240,6 @@ go_library(
         "//pkg/sentry/fs/lock",
         "//pkg/sentry/fs/timerfd",
         "//pkg/sentry/fsbridge",
-        "//pkg/sentry/fsimpl/kernfs",
         "//pkg/sentry/fsimpl/pipefs",
         "//pkg/sentry/fsimpl/sockfs",
         "//pkg/sentry/fsimpl/timerfd",
diff --git a/pkg/sentry/kernel/threads.go b/pkg/sentry/kernel/threads.go
index fdadb52c0..e9da99067 100644
--- a/pkg/sentry/kernel/threads.go
+++ b/pkg/sentry/kernel/threads.go
@@ -216,7 +216,7 @@ func (ns *PIDNamespace) TaskWithID(tid ThreadID) *Task {
 	return t
 }
 
-// ThreadGroupWithID returns the thread group lead by the task with thread ID
+// ThreadGroupWithID returns the thread group led by the task with thread ID
 // tid in PID namespace ns. If no task has that TID, or if the task with that
 // TID is not a thread group leader, ThreadGroupWithID returns nil.
 func (ns *PIDNamespace) ThreadGroupWithID(tid ThreadID) *ThreadGroup {
@@ -292,6 +292,11 @@ func (ns *PIDNamespace) UserNamespace() *auth.UserNamespace {
 	return ns.userns
 }
 
+// Root returns the root PID namespace of ns.
+func (ns *PIDNamespace) Root() *PIDNamespace {
+	return ns.owner.Root
+}
+
 // A threadGroupNode defines the relationship between a thread group and the
 // rest of the system. Conceptually, threadGroupNode is data belonging to the
 // owning TaskSet, as if TaskSet contained a field `nodes
@@ -485,3 +490,8 @@ func (t *Task) Parent() *Task {
 func (t *Task) ThreadID() ThreadID {
 	return t.tg.pidns.IDOfTask(t)
 }
+
+// TGIDInRoot returns t's TGID in the root PID namespace.
+func (t *Task) TGIDInRoot() ThreadID {
+	return t.tg.pidns.owner.Root.IDOfThreadGroup(t.tg)
+}