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cgroupfs: Per cgroups(7), PID/TID 0 refers to the current task.

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PiperOrigin-RevId: 447090229
This commit is contained in:
Rahat Mahmood
2022-05-06 16:06:43 -07:00
committed by gVisor bot
parent 71add37390
commit 409f32743b
2 changed files with 49 additions and 2 deletions
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pkg/sentry/fsimpl/cgroupfs/base.go
+13 -2
View File
@@ -363,7 +363,13 @@ func (d *cgroupProcsData) Write(ctx context.Context, fd *vfs.FileDescription, sr
t := kernel.TaskFromContext(ctx)
currPidns := t.ThreadGroup().PIDNamespace()
targetTG := currPidns.ThreadGroupWithID(kernel.ThreadID(tgid))
var targetTG *kernel.ThreadGroup
if tgid != 0 {
targetTG = currPidns.ThreadGroupWithID(kernel.ThreadID(tgid))
} else {
targetTG = t.ThreadGroup()
}
if targetTG == nil {
return 0, linuxerr.EINVAL
}
@@ -405,7 +411,12 @@ func (d *tasksData) Write(ctx context.Context, fd *vfs.FileDescription, src user
t := kernel.TaskFromContext(ctx)
currPidns := t.ThreadGroup().PIDNamespace()
targetTask := currPidns.TaskWithID(kernel.ThreadID(tid))
var targetTask *kernel.Task
if tid != 0 {
targetTask = currPidns.TaskWithID(kernel.ThreadID(tid))
} else {
targetTask = t
}
if targetTask == nil {
return 0, linuxerr.EINVAL
}
test/syscalls/linux/cgroup.cc
+36
View File
@@ -549,6 +549,42 @@ TEST(Cgroup, Rename) {
EXPECT_THAT(Exists(child.Relpath("oldname")), IsPosixErrorOkAndHolds(false));
}
TEST(Cgroup, PIDZeroMovesSelf) {
SKIP_IF(!CgroupsAvailable());
Mounter m(ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir()));
Cgroup c = ASSERT_NO_ERRNO_AND_VALUE(m.MountCgroupfs(""));
Cgroup child = ASSERT_NO_ERRNO_AND_VALUE(c.CreateChild("child"));
// Source contains this process.
EXPECT_NO_ERRNO(c.ContainsCallingProcess());
// Move to child by writing PID 0.
ASSERT_NO_ERRNO(child.WriteIntegerControlFile("cgroup.procs", 0));
// Destination now contains this process, and source does not.
EXPECT_NO_ERRNO(child.ContainsCallingProcess());
auto procs = ASSERT_NO_ERRNO_AND_VALUE(c.Procs());
EXPECT_FALSE(procs.contains(getpid()));
}
TEST(Cgroup, TIDZeroMovesSelf) {
SKIP_IF(!CgroupsAvailable());
Mounter m(ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir()));
Cgroup c = ASSERT_NO_ERRNO_AND_VALUE(m.MountCgroupfs(""));
Cgroup child = ASSERT_NO_ERRNO_AND_VALUE(c.CreateChild("child"));
// Source contains this thread.
EXPECT_NO_ERRNO(c.ContainsCallingThread());
// Move to child by writing TID 0.
ASSERT_NO_ERRNO(child.WriteIntegerControlFile("tasks", 0));
// Destination now contains this thread, and source does not.
EXPECT_NO_ERRNO(child.ContainsCallingThread());
auto tasks = ASSERT_NO_ERRNO_AND_VALUE(c.Tasks());
EXPECT_FALSE(tasks.contains(syscall(SYS_gettid)));
}
TEST(MemoryCgroup, MemoryUsageInBytes) {
SKIP_IF(!CgroupsAvailable());