100 lines
3.0 KiB
Go
100 lines
3.0 KiB
Go
// Copyright 2018 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package dev
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import (
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"strconv"
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"gvisor.googlesource.com/gvisor/pkg/sentry/context"
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"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
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"gvisor.googlesource.com/gvisor/pkg/syserror"
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)
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// Optional key containing boolean flag which specifies if Android Binder IPC should be enabled.
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const binderEnabledKey = "binder_enabled"
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// Optional key containing boolean flag which specifies if Android ashmem should be enabled.
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const ashmemEnabledKey = "ashmem_enabled"
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// filesystem is a devtmpfs.
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//
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// +stateify savable
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type filesystem struct{}
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var _ fs.Filesystem = (*filesystem)(nil)
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func init() {
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fs.RegisterFilesystem(&filesystem{})
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}
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// FilesystemName is the name underwhich the filesystem is registered.
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// Name matches drivers/base/devtmpfs.c:dev_fs_type.name.
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const FilesystemName = "devtmpfs"
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// Name is the name of the file system.
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func (*filesystem) Name() string {
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return FilesystemName
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}
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// AllowUserMount allows users to mount(2) this file system.
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func (*filesystem) AllowUserMount() bool {
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return true
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}
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// AllowUserList allows this filesystem to be listed in /proc/filesystems.
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func (*filesystem) AllowUserList() bool {
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return true
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}
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// Flags returns that there is nothing special about this file system.
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//
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// In Linux, devtmpfs does the same thing.
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func (*filesystem) Flags() fs.FilesystemFlags {
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return 0
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}
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// Mount returns a devtmpfs root that can be positioned in the vfs.
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func (f *filesystem) Mount(ctx context.Context, device string, flags fs.MountSourceFlags, data string, _ interface{}) (*fs.Inode, error) {
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// device is always ignored.
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// devtmpfs backed by ramfs ignores bad options. See fs/ramfs/inode.c:ramfs_parse_options.
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// -> we should consider parsing the mode and backing devtmpfs by this.
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// Parse generic comma-separated key=value options.
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options := fs.GenericMountSourceOptions(data)
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// binerEnabledKey is optional and binder is disabled by default.
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binderEnabled := false
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if beStr, exists := options[binderEnabledKey]; exists {
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var err error
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binderEnabled, err = strconv.ParseBool(beStr)
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if err != nil {
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return nil, syserror.EINVAL
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}
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}
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// ashmemEnabledKey is optional and ashmem is disabled by default.
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ashmemEnabled := false
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if aeStr, exists := options[ashmemEnabledKey]; exists {
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var err error
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ashmemEnabled, err = strconv.ParseBool(aeStr)
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if err != nil {
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return nil, syserror.EINVAL
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}
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}
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// Construct the devtmpfs root.
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return New(ctx, fs.NewNonCachingMountSource(f, flags), binderEnabled, ashmemEnabled), nil
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}
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