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// Copyright 2018 Google LLC
//
// 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 (
"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/fs/proc/device"
"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
)
// taskOwnedInodeOps wraps an fs.InodeOperations and overrides the UnstableAttr
// method to return the task as the owner.
//
// +stateify savable
type taskOwnedInodeOps struct {
fs.InodeOperations
// t is the task that owns this file.
t *kernel.Task
}
// UnstableAttr implement fs.InodeOperations.UnstableAttr.
func (i *taskOwnedInodeOps) UnstableAttr(ctx context.Context, inode *fs.Inode) (fs.UnstableAttr, error) {
uattr, err := i.InodeOperations.UnstableAttr(ctx, inode)
if err != nil {
return fs.UnstableAttr{}, err
}
// Set the task owner as the file owner.
creds := i.t.Credentials()
uattr.Owner = fs.FileOwner{creds.EffectiveKUID, creds.EffectiveKGID}
return uattr, nil
}
// staticFileInodeOps is an InodeOperations implementation that can be used to
// return file contents which are constant. This file is not writable and will
// always have mode 0444.
//
// +stateify savable
type staticFileInodeOps struct {
fsutil.InodeDenyWriteChecker `state:"nosave"`
fsutil.InodeNoExtendedAttributes `state:"nosave"`
fsutil.InodeNoopRelease `state:"nosave"`
fsutil.InodeNoopTruncate `state:"nosave"`
fsutil.InodeNoopWriteOut `state:"nosave"`
fsutil.InodeNotDirectory `state:"nosave"`
fsutil.InodeNotMappable `state:"nosave"`
fsutil.InodeNotSocket `state:"nosave"`
fsutil.InodeNotSymlink `state:"nosave"`
fsutil.InodeVirtual `state:"nosave"`
fsutil.InodeSimpleAttributes
fsutil.InodeStaticFileGetter
}
var _ fs.InodeOperations = (*staticFileInodeOps)(nil)
// newStaticFileInode returns a procfs InodeOperations with static contents.
func newStaticProcInode(ctx context.Context, msrc *fs.MountSource, contents []byte) *fs.Inode {
iops := &staticFileInodeOps{
InodeSimpleAttributes: fsutil.NewInodeSimpleAttributes(ctx, fs.RootOwner, fs.FilePermsFromMode(0444), linux.PROC_SUPER_MAGIC),
InodeStaticFileGetter: fsutil.InodeStaticFileGetter{
Contents: contents,
},
}
return newProcInode(iops, msrc, fs.SpecialFile, nil)
}
// newProcInode creates a new inode from the given inode operations.
func newProcInode(iops fs.InodeOperations, msrc *fs.MountSource, typ fs.InodeType, t *kernel.Task) *fs.Inode {
sattr := fs.StableAttr{
DeviceID: device.ProcDevice.DeviceID(),
InodeID: device.ProcDevice.NextIno(),
BlockSize: usermem.PageSize,
Type: typ,
}
if t != nil {
iops = &taskOwnedInodeOps{iops, t}
}
return fs.NewInode(iops, msrc, sattr)
}
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