3 files changed, 152 insertions, 0 deletions
diff --git a/pkg/sentry/devices/miscdev/BUILD b/pkg/sentry/devices/miscdev/BUILD
new file mode 100644
index 000000000..aaa76c5d2
--- /dev/null
+++ b/pkg/sentry/devices/miscdev/BUILD
@@ -0,0 +1,20 @@
+load("//tools:defs.bzl", "go_library")
+
+licenses(["notice"])
+
+go_library(
+    name = "miscdev",
+    srcs = [
+        "fuse.go",
+        "miscdev.go",
+    ],
+    visibility = ["//pkg/sentry:internal"],
+    deps = [
+        "//pkg/abi/linux",
+        "//pkg/context",
+        "//pkg/sentry/fsimpl/devtmpfs",
+        "//pkg/sentry/vfs",
+        "//pkg/syserror",
+        "//pkg/usermem",
+    ],
+)
diff --git a/pkg/sentry/devices/miscdev/fuse.go b/pkg/sentry/devices/miscdev/fuse.go
new file mode 100644
index 000000000..d0a963191
--- /dev/null
+++ b/pkg/sentry/devices/miscdev/fuse.go
@@ -0,0 +1,78 @@
+// 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 miscdev
+
+import (
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/usermem"
+)
+
+const fuseDevMinor = 229
+
+// fuseDevice implements vfs.Device for /dev/fuse.
+type fuseDevice struct{}
+
+// Open implements vfs.Device.Open.
+func (fuseDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
+	var fd FUSEDeviceFile
+	if err := fd.vfsfd.Init(&fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{
+		UseDentryMetadata: true,
+	}); err != nil {
+		return nil, err
+	}
+	return &fd.vfsfd, nil
+}
+
+// FUSEDeviceFile implements vfs.FileDescriptionImpl for /dev/fuse.
+type FUSEDeviceFile struct {
+	vfsfd vfs.FileDescription
+	vfs.FileDescriptionDefaultImpl
+	vfs.DentryMetadataFileDescriptionImpl
+	vfs.NoLockFD
+
+	// TODO(gvisor.dev/issue/2987): Add all the data structures needed to enqueue
+	// and deque requests, control synchronization and establish communication
+	// between the FUSE kernel module and the /dev/fuse character device.
+}
+
+// Release implements vfs.FileDescriptionImpl.Release.
+func (fd *FUSEDeviceFile) Release() {}
+
+// PRead implements vfs.FileDescriptionImpl.PRead.
+func (fd *FUSEDeviceFile) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
+	return 0, syserror.ENOSYS
+}
+
+// Read implements vfs.FileDescriptionImpl.Read.
+func (fd *FUSEDeviceFile) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
+	return 0, syserror.ENOSYS
+}
+
+// PWrite implements vfs.FileDescriptionImpl.PWrite.
+func (fd *FUSEDeviceFile) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
+	return 0, syserror.ENOSYS
+}
+
+// Write implements vfs.FileDescriptionImpl.Write.
+func (fd *FUSEDeviceFile) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
+	return 0, syserror.ENOSYS
+}
+
+// Seek implements vfs.FileDescriptionImpl.Seek.
+func (fd *FUSEDeviceFile) Seek(ctx context.Context, offset int64, whence int32) (int64, error) {
+	return 0, syserror.ENOSYS
+}
diff --git a/pkg/sentry/devices/miscdev/miscdev.go b/pkg/sentry/devices/miscdev/miscdev.go
new file mode 100644
index 000000000..500d92ed9
--- /dev/null
+++ b/pkg/sentry/devices/miscdev/miscdev.go
@@ -0,0 +1,54 @@
+// 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 miscdev implements "misc" character devices, as implemented in Linux
+// by drivers/char/misc.c and fs/fuse/dev.c.
+package miscdev
+
+import (
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/sentry/fsimpl/devtmpfs"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+)
+
+// miscDevMajor is the major device number for devices defined in this package.
+const miscDevMajor = linux.MISC_MAJOR
+
+// Register registers all devices implemented by this package in vfsObj.
+func Register(vfsObj *vfs.VirtualFilesystem) error {
+	for minor, dev := range map[uint32]vfs.Device{
+		fuseDevMinor: fuseDevice{},
+	} {
+		if err := vfsObj.RegisterDevice(vfs.CharDevice, miscDevMajor, minor, dev, &vfs.RegisterDeviceOptions{
+			GroupName: "misc",
+		}); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// CreateDevtmpfsFiles creates device special files in dev representing all
+// devices implemented by this package.
+func CreateDevtmpfsFiles(ctx context.Context, dev *devtmpfs.Accessor) error {
+	for minor, name := range map[uint32]string{
+		fuseDevMinor: "fuse",
+	} {
+		if err := dev.CreateDeviceFile(ctx, name, vfs.CharDevice, miscDevMajor, minor, 0666 /* mode */); err != nil {
+			return err
+		}
+	}
+	return nil
+}