1 files changed, 64 insertions, 0 deletions
diff --git a/pkg/sentry/fs/sys/sys.go b/pkg/sentry/fs/sys/sys.go
new file mode 100644
index 000000000..d20ef91fa
--- /dev/null
+++ b/pkg/sentry/fs/sys/sys.go
@@ -0,0 +1,64 @@
+// Copyright 2018 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 sys implements a sysfs filesystem.
+package sys
+
+import (
+	"gvisor.googlesource.com/gvisor/pkg/sentry/context"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/fs/ramfs"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
+)
+
+func newFile(node fs.InodeOperations, msrc *fs.MountSource) *fs.Inode {
+	sattr := fs.StableAttr{
+		DeviceID:  sysfsDevice.DeviceID(),
+		InodeID:   sysfsDevice.NextIno(),
+		BlockSize: usermem.PageSize,
+		Type:      fs.SpecialFile,
+	}
+	return fs.NewInode(node, msrc, sattr)
+}
+
+func newDir(ctx context.Context, msrc *fs.MountSource, contents map[string]*fs.Inode) *fs.Inode {
+	d := ramfs.NewDir(ctx, contents, fs.RootOwner, fs.FilePermsFromMode(0555))
+	return fs.NewInode(d, msrc, fs.StableAttr{
+		DeviceID:  sysfsDevice.DeviceID(),
+		InodeID:   sysfsDevice.NextIno(),
+		BlockSize: usermem.PageSize,
+		Type:      fs.SpecialDirectory,
+	})
+}
+
+// New returns the root node of a partial simple sysfs.
+func New(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
+	return newDir(ctx, msrc, map[string]*fs.Inode{
+		// Add a basic set of top-level directories. In Linux, these
+		// are dynamically added depending on the KConfig. Here we just
+		// add the most common ones.
+		"block": newDir(ctx, msrc, nil),
+		"bus":   newDir(ctx, msrc, nil),
+		"class": newDir(ctx, msrc, map[string]*fs.Inode{
+			"power_supply": newDir(ctx, msrc, nil),
+		}),
+		"dev":      newDir(ctx, msrc, nil),
+		"devices":  newDevicesDir(ctx, msrc),
+		"firmware": newDir(ctx, msrc, nil),
+		"fs":       newDir(ctx, msrc, nil),
+		"kernel":   newDir(ctx, msrc, nil),
+		"module":   newDir(ctx, msrc, nil),
+		"power":    newDir(ctx, msrc, nil),
+	})
+}