1 files changed, 91 insertions, 0 deletions
diff --git a/pkg/sentry/fs/sys/devices.go b/pkg/sentry/fs/sys/devices.go
new file mode 100644
index 000000000..54f35c6a0
--- /dev/null
+++ b/pkg/sentry/fs/sys/devices.go
@@ -0,0 +1,91 @@
+// 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
+
+import (
+	"fmt"
+
+	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/context"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/fs/fsutil"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
+)
+
+// +stateify savable
+type cpunum struct {
+	fsutil.InodeGenericChecker       `state:"nosave"`
+	fsutil.InodeNoExtendedAttributes `state:"nosave"`
+	fsutil.InodeNoopRelease          `state:"nosave"`
+	fsutil.InodeNoopWriteOut         `state:"nosave"`
+	fsutil.InodeNotAllocatable       `state:"nosave"`
+	fsutil.InodeNotDirectory         `state:"nosave"`
+	fsutil.InodeNotMappable          `state:"nosave"`
+	fsutil.InodeNotSocket            `state:"nosave"`
+	fsutil.InodeNotSymlink           `state:"nosave"`
+	fsutil.InodeNotTruncatable       `state:"nosave"`
+	fsutil.InodeNotVirtual           `state:"nosave"`
+
+	fsutil.InodeSimpleAttributes
+	fsutil.InodeStaticFileGetter
+}
+
+var _ fs.InodeOperations = (*cpunum)(nil)
+
+func newPossible(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
+	var maxCore uint
+	k := kernel.KernelFromContext(ctx)
+	if k != nil {
+		maxCore = k.ApplicationCores() - 1
+	}
+	contents := []byte(fmt.Sprintf("0-%d\n", maxCore))
+
+	c := &cpunum{
+		InodeSimpleAttributes: fsutil.NewInodeSimpleAttributes(ctx, fs.RootOwner, fs.FilePermsFromMode(0444), linux.SYSFS_MAGIC),
+		InodeStaticFileGetter: fsutil.InodeStaticFileGetter{
+			Contents: contents,
+		},
+	}
+	return newFile(c, msrc)
+}
+
+func newCPU(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
+	m := map[string]*fs.Inode{
+		"online":   newPossible(ctx, msrc),
+		"possible": newPossible(ctx, msrc),
+		"present":  newPossible(ctx, msrc),
+	}
+
+	// Add directories for each of the cpus.
+	if k := kernel.KernelFromContext(ctx); k != nil {
+		for i := 0; uint(i) < k.ApplicationCores(); i++ {
+			m[fmt.Sprintf("cpu%d", i)] = newDir(ctx, msrc, nil)
+		}
+	}
+
+	return newDir(ctx, msrc, m)
+}
+
+func newSystemDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
+	return newDir(ctx, msrc, map[string]*fs.Inode{
+		"cpu": newCPU(ctx, msrc),
+	})
+}
+
+func newDevicesDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
+	return newDir(ctx, msrc, map[string]*fs.Inode{
+		"system": newSystemDir(ctx, msrc),
+	})
+}