1 files changed, 117 insertions, 0 deletions
diff --git a/pkg/sentry/fsimpl/proc/filesystem.go b/pkg/sentry/fsimpl/proc/filesystem.go
new file mode 100644
index 000000000..2463d51cd
--- /dev/null
+++ b/pkg/sentry/fsimpl/proc/filesystem.go
@@ -0,0 +1,117 @@
+// Copyright 2019 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 proc implements a partial in-memory file system for procfs.
+package proc
+
+import (
+	"fmt"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+)
+
+// Name is the default filesystem name.
+const Name = "proc"
+
+// FilesystemType is the factory class for procfs.
+//
+// +stateify savable
+type FilesystemType struct{}
+
+var _ vfs.FilesystemType = (*FilesystemType)(nil)
+
+// Name implements vfs.FilesystemType.Name.
+func (FilesystemType) Name() string {
+	return Name
+}
+
+type filesystem struct {
+	kernfs.Filesystem
+
+	devMinor uint32
+}
+
+// GetFilesystem implements vfs.FilesystemType.GetFilesystem.
+func (ft FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, source string, opts vfs.GetFilesystemOptions) (*vfs.Filesystem, *vfs.Dentry, error) {
+	k := kernel.KernelFromContext(ctx)
+	if k == nil {
+		return nil, nil, fmt.Errorf("procfs requires a kernel")
+	}
+	pidns := kernel.PIDNamespaceFromContext(ctx)
+	if pidns == nil {
+		return nil, nil, fmt.Errorf("procfs requires a PID namespace")
+	}
+	devMinor, err := vfsObj.GetAnonBlockDevMinor()
+	if err != nil {
+		return nil, nil, err
+	}
+	procfs := &filesystem{
+		devMinor: devMinor,
+	}
+	procfs.VFSFilesystem().Init(vfsObj, &ft, procfs)
+
+	var cgroups map[string]string
+	if opts.InternalData != nil {
+		data := opts.InternalData.(*InternalData)
+		cgroups = data.Cgroups
+	}
+
+	_, dentry := procfs.newTasksInode(k, pidns, cgroups)
+	return procfs.VFSFilesystem(), dentry.VFSDentry(), nil
+}
+
+// Release implements vfs.FilesystemImpl.Release.
+func (fs *filesystem) Release(ctx context.Context) {
+	fs.Filesystem.VFSFilesystem().VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor)
+	fs.Filesystem.Release(ctx)
+}
+
+// dynamicInode is an overfitted interface for common Inodes with
+// dynamicByteSource types used in procfs.
+type dynamicInode interface {
+	kernfs.Inode
+	vfs.DynamicBytesSource
+
+	Init(creds *auth.Credentials, devMajor, devMinor uint32, ino uint64, data vfs.DynamicBytesSource, perm linux.FileMode)
+}
+
+func (fs *filesystem) newDentry(creds *auth.Credentials, ino uint64, perm linux.FileMode, inode dynamicInode) *kernfs.Dentry {
+	inode.Init(creds, linux.UNNAMED_MAJOR, fs.devMinor, ino, inode, perm)
+
+	d := &kernfs.Dentry{}
+	d.Init(inode)
+	return d
+}
+
+type staticFile struct {
+	kernfs.DynamicBytesFile
+	vfs.StaticData
+}
+
+var _ dynamicInode = (*staticFile)(nil)
+
+func newStaticFile(data string) *staticFile {
+	return &staticFile{StaticData: vfs.StaticData{Data: data}}
+}
+
+// InternalData contains internal data passed in to the procfs mount via
+// vfs.GetFilesystemOptions.InternalData.
+type InternalData struct {
+	Cgroups map[string]string
+}