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// 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 host
import (
"fmt"
"syscall"
"gvisor.googlesource.com/gvisor/pkg/sentry/context"
"gvisor.googlesource.com/gvisor/pkg/sentry/device"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
)
// beforeSave is invoked by stateify.
func (i *inodeFileState) beforeSave() {
if !i.queue.IsEmpty() {
panic("event queue must be empty")
}
if !i.descriptor.donated && i.sattr.Type == fs.RegularFile {
uattr, err := i.unstableAttr(context.Background())
if err != nil {
panic(fmt.Sprintf("failed to get unstable atttribute of %s: %v", i.mops.inodeMappings[i.sattr.InodeID], err))
}
i.savedUAttr = &uattr
}
}
// afterLoad is invoked by stateify.
func (i *inodeFileState) afterLoad() {
// Initialize the descriptor value.
if err := i.descriptor.initAfterLoad(i.mops, i.sattr.InodeID, &i.queue); err != nil {
panic(fmt.Sprintf("failed to load value of descriptor: %v", err))
}
// Remap the inode number.
var s syscall.Stat_t
if err := syscall.Fstat(i.FD(), &s); err != nil {
panic(fmt.Sprintf("failed to get metadata for fd %d: %v", i.FD(), err))
}
key := device.MultiDeviceKey{
Device: s.Dev,
Inode: s.Ino,
}
if !hostFileDevice.Load(key, i.sattr.InodeID) {
// This means there was a conflict at s.Dev and s.Ino with
// another inode mapping: two files that were unique on the
// saved filesystem are no longer unique on this filesystem.
// Since this violates the contract that filesystems cannot
// change across save and restore, error out.
panic(fmt.Sprintf("host %s conflict in host device mappings: %s", key, hostFileDevice))
}
if !i.descriptor.donated && i.sattr.Type == fs.RegularFile {
env, ok := fs.CurrentRestoreEnvironment()
if !ok {
panic("missing restore environment")
}
uattr := unstableAttr(i.mops, &s)
if env.ValidateFileSize && uattr.Size != i.savedUAttr.Size {
panic(fmt.Errorf("file size has changed for %s: previously %d, now %d", i.mops.inodeMappings[i.sattr.InodeID], i.savedUAttr.Size, uattr.Size))
}
if env.ValidateFileTimestamp && uattr.ModificationTime != i.savedUAttr.ModificationTime {
panic(fmt.Errorf("file modification time has changed for %s: previously %v, now %v", i.mops.inodeMappings[i.sattr.InodeID], i.savedUAttr.ModificationTime, uattr.ModificationTime))
}
i.savedUAttr = nil
}
}
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