1 files changed, 119 insertions, 0 deletions
diff --git a/pkg/sentry/fsimpl/devtmpfs/devtmpfs_test.go b/pkg/sentry/fsimpl/devtmpfs/devtmpfs_test.go
new file mode 100644
index 000000000..82c58c900
--- /dev/null
+++ b/pkg/sentry/fsimpl/devtmpfs/devtmpfs_test.go
@@ -0,0 +1,119 @@
+// Copyright 2020 The gVisor Authors.
+//
+// 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 devtmpfs
+
+import (
+	"testing"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/fspath"
+	"gvisor.dev/gvisor/pkg/sentry/contexttest"
+	"gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+)
+
+func TestDevtmpfs(t *testing.T) {
+	ctx := contexttest.Context(t)
+	creds := auth.CredentialsFromContext(ctx)
+
+	vfsObj := vfs.New()
+	// Register tmpfs just so that we can have a root filesystem that isn't
+	// devtmpfs.
+	vfsObj.MustRegisterFilesystemType("tmpfs", tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
+		AllowUserMount: true,
+	})
+	vfsObj.MustRegisterFilesystemType("devtmpfs", &FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
+		AllowUserMount: true,
+	})
+
+	// Create a test mount namespace with devtmpfs mounted at "/dev".
+	const devPath = "/dev"
+	mntns, err := vfsObj.NewMountNamespace(ctx, creds, "tmpfs" /* source */, "tmpfs" /* fsTypeName */, &vfs.GetFilesystemOptions{})
+	if err != nil {
+		t.Fatalf("failed to create tmpfs root mount: %v", err)
+	}
+	defer mntns.DecRef(vfsObj)
+	root := mntns.Root()
+	defer root.DecRef()
+	devpop := vfs.PathOperation{
+		Root:  root,
+		Start: root,
+		Path:  fspath.Parse(devPath),
+	}
+	if err := vfsObj.MkdirAt(ctx, creds, &devpop, &vfs.MkdirOptions{
+		Mode: 0755,
+	}); err != nil {
+		t.Fatalf("failed to create mount point: %v", err)
+	}
+	if err := vfsObj.MountAt(ctx, creds, "devtmpfs" /* source */, &devpop, "devtmpfs" /* fsTypeName */, &vfs.MountOptions{}); err != nil {
+		t.Fatalf("failed to mount devtmpfs: %v", err)
+	}
+
+	a, err := NewAccessor(ctx, vfsObj, creds, "devtmpfs")
+	if err != nil {
+		t.Fatalf("failed to create devtmpfs.Accessor: %v", err)
+	}
+	defer a.Release()
+
+	// Create "userspace-initialized" files using a devtmpfs.Accessor.
+	if err := a.UserspaceInit(ctx); err != nil {
+		t.Fatalf("failed to userspace-initialize devtmpfs: %v", err)
+	}
+	// Created files should be visible in the test mount namespace.
+	abspath := devPath + "/fd"
+	target, err := vfsObj.ReadlinkAt(ctx, creds, &vfs.PathOperation{
+		Root:  root,
+		Start: root,
+		Path:  fspath.Parse(abspath),
+	})
+	if want := "/proc/self/fd"; err != nil || target != want {
+		t.Fatalf("readlink(%q): got (%q, %v), wanted (%q, nil)", abspath, target, err, want)
+	}
+
+	// Create a dummy device special file using a devtmpfs.Accessor.
+	const (
+		pathInDev = "dummy"
+		kind      = vfs.CharDevice
+		major     = 12
+		minor     = 34
+		perms     = 0600
+		wantMode  = linux.S_IFCHR | perms
+	)
+	if err := a.CreateDeviceFile(ctx, pathInDev, kind, major, minor, perms); err != nil {
+		t.Fatalf("failed to create device file: %v", err)
+	}
+	// The device special file should be visible in the test mount namespace.
+	abspath = devPath + "/" + pathInDev
+	stat, err := vfsObj.StatAt(ctx, creds, &vfs.PathOperation{
+		Root:  root,
+		Start: root,
+		Path:  fspath.Parse(abspath),
+	}, &vfs.StatOptions{
+		Mask: linux.STATX_TYPE | linux.STATX_MODE,
+	})
+	if err != nil {
+		t.Fatalf("failed to stat device file at %q: %v", abspath, err)
+	}
+	if stat.Mode != wantMode {
+		t.Errorf("device file mode: got %v, wanted %v", stat.Mode, wantMode)
+	}
+	if stat.RdevMajor != major {
+		t.Errorf("major device number: got %v, wanted %v", stat.RdevMajor, major)
+	}
+	if stat.RdevMinor != minor {
+		t.Errorf("minor device number: got %v, wanted %v", stat.RdevMinor, minor)
+	}
+}