Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 64 insertions, 0 deletions

diff --git a/pkg/sentry/fs/proc/cpuinfo.go b/pkg/sentry/fs/proc/cpuinfo.go
new file mode 100644
index 000000000..f80aaa5b1
--- /dev/null
+++ b/pkg/sentry/fs/proc/cpuinfo.go
@@ -0,0 +1,64 @@
+// 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 proc
+
+import (
+	"io"
+
+	"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/kernel"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
+)
+
+// cpuinfo is a file describing the CPU capabilities.
+//
+// Presently cpuinfo never changes, so it doesn't need to be a SeqFile.
+type cpuinfo struct {
+	ramfs.Entry
+
+	// k is the system kernel.
+	k *kernel.Kernel
+}
+
+// DeprecatedPreadv implements fs.InodeOperations.DeprecatedPreadv.
+func (c *cpuinfo) DeprecatedPreadv(ctx context.Context, dst usermem.IOSequence, offset int64) (int64, error) {
+	features := c.k.FeatureSet()
+	if features == nil {
+		// Kernel is always initialized with a FeatureSet.
+		panic("cpuinfo read with nil FeatureSet")
+	}
+
+	contents := make([]byte, 0, 1024)
+	for i, max := uint(0), c.k.ApplicationCores(); i < max; i++ {
+		contents = append(contents, []byte(features.CPUInfo(i))...)
+	}
+	if offset >= int64(len(contents)) {
+		return 0, io.EOF
+	}
+
+	n, err := dst.CopyOut(ctx, contents[offset:])
+	return int64(n), err
+}
+
+func (p *proc) newCPUInfo(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
+	f := &cpuinfo{
+		k: p.k,
+	}
+	f.InitEntry(ctx, fs.RootOwner, fs.FilePermsFromMode(0444))
+
+	return newFile(f, msrc, fs.SpecialFile, nil)
+}