Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

5 files changed, 189 insertions, 0 deletions

diff --git a/pkg/sentry/platform/procid/BUILD b/pkg/sentry/platform/procid/BUILD
new file mode 100644
index 000000000..5db4f6261
--- /dev/null
+++ b/pkg/sentry/platform/procid/BUILD
@@ -0,0 +1,32 @@
+package(licenses = ["notice"])  # Apache 2.0
+
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "procid",
+    srcs = [
+        "procid.go",
+        "procid_amd64.s",
+    ],
+    importpath = "gvisor.googlesource.com/gvisor/pkg/sentry/platform/procid",
+    visibility = ["//pkg/sentry:internal"],
+)
+
+go_test(
+    name = "procid_test",
+    size = "small",
+    srcs = [
+        "procid_test.go",
+    ],
+    embed = [":procid"],
+)
+
+go_test(
+    name = "procid_net_test",
+    size = "small",
+    srcs = [
+        "procid_net_test.go",
+        "procid_test.go",
+    ],
+    embed = [":procid"],
+)
diff --git a/pkg/sentry/platform/procid/procid.go b/pkg/sentry/platform/procid/procid.go
new file mode 100644
index 000000000..5f861908f
--- /dev/null
+++ b/pkg/sentry/platform/procid/procid.go
@@ -0,0 +1,21 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package procid provides a way to get the current system thread identifier.
+package procid
+
+// Current returns the current system thread identifier.
+//
+// Precondition: This should only be called with the runtime OS thread locked.
+func Current() uint64
diff --git a/pkg/sentry/platform/procid/procid_amd64.s b/pkg/sentry/platform/procid/procid_amd64.s
new file mode 100644
index 000000000..ead4e3d91
--- /dev/null
+++ b/pkg/sentry/platform/procid/procid_amd64.s
@@ -0,0 +1,30 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build amd64
+// +build go1.8
+// +build !go1.11
+
+#include "textflag.h"
+
+TEXT ·Current(SB),NOSPLIT,$0-8
+	// The offset specified here is the m_procid offset for Go1.8+.
+	// Changes to this offset should be caught by the tests, and major
+	// version changes require an explicit tag change above.
+	MOVQ TLS, AX
+	MOVQ 0(AX)(TLS*1), AX
+	MOVQ 48(AX), AX // g_m (may change in future versions)
+	MOVQ 72(AX), AX // m_procid (may change in future versions)
+	MOVQ AX, ret+0(FP)
+	RET
diff --git a/pkg/sentry/platform/procid/procid_net_test.go b/pkg/sentry/platform/procid/procid_net_test.go
new file mode 100644
index 000000000..2d1605a08
--- /dev/null
+++ b/pkg/sentry/platform/procid/procid_net_test.go
@@ -0,0 +1,21 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procid
+
+// This file is just to force the inclusion of the "net" package, which will
+// make the test binary a cgo one.
+import (
+	_ "net"
+)
diff --git a/pkg/sentry/platform/procid/procid_test.go b/pkg/sentry/platform/procid/procid_test.go
new file mode 100644
index 000000000..5e44da36f
--- /dev/null
+++ b/pkg/sentry/platform/procid/procid_test.go
@@ -0,0 +1,85 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procid
+
+import (
+	"os"
+	"runtime"
+	"sync"
+	"syscall"
+	"testing"
+)
+
+// runOnMain is used to send functions to run on the main (initial) thread.
+var runOnMain = make(chan func(), 10)
+
+func checkProcid(t *testing.T, start *sync.WaitGroup, done *sync.WaitGroup) {
+	defer done.Done()
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	start.Done()
+	start.Wait()
+
+	procID := Current()
+	tid := syscall.Gettid()
+
+	if procID != uint64(tid) {
+		t.Logf("Bad procid: expected %v, got %v", tid, procID)
+		t.Fail()
+	}
+}
+
+func TestProcidInitialized(t *testing.T) {
+	var start sync.WaitGroup
+	var done sync.WaitGroup
+
+	count := 100
+	start.Add(count + 1)
+	done.Add(count + 1)
+
+	// Run the check on the main thread.
+	//
+	// When cgo is not included, the only case when procid isn't initialized
+	// is in the main (initial) thread, so we have to test this case
+	// specifically.
+	runOnMain <- func() {
+		checkProcid(t, &start, &done)
+	}
+
+	// Run the check on a number of different threads.
+	for i := 0; i < count; i++ {
+		go checkProcid(t, &start, &done)
+	}
+
+	done.Wait()
+}
+
+func TestMain(m *testing.M) {
+	// Make sure we remain at the main (initial) thread.
+	runtime.LockOSThread()
+
+	// Start running tests in a different goroutine.
+	go func() {
+		os.Exit(m.Run())
+	}()
+
+	// Execute any functions that have been sent for execution in the main
+	// thread.
+	for f := range runOnMain {
+		f()
+	}
+}