/
autosave.go
124 lines (113 loc) · 3.64 KB
/
autosave.go
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// Copyright 2024 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 boot
import (
"bytes"
"fmt"
"os"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/log"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/state"
"gvisor.dev/gvisor/pkg/sentry/strace"
"gvisor.dev/gvisor/pkg/sync"
)
func getSaveOpts(l *Loader, k *kernel.Kernel, isResume bool) state.SaveOpts {
t, _ := state.CPUTime()
log.Infof("Before save CPU usage: %s", t.String())
saveOpts := state.SaveOpts{
Key: nil,
Resume: isResume,
Callback: func(err error) {
t1, _ := state.CPUTime()
log.Infof("Save CPU usage: %s", (t1 - t).String())
if err == nil {
log.Infof("Save succeeded: exiting...")
k.SetSaveSuccess(true)
} else {
log.Warningf("Save failed: exiting... %v", err)
k.SetSaveError(err)
}
if !isResume {
// Kill the sandbox.
k.Kill(linux.WaitStatusExit(0))
}
},
}
return saveOpts
}
func getTargetForSaveResume(l *Loader) func(k *kernel.Kernel) {
return func(k *kernel.Kernel) {
saveOpts := getSaveOpts(l, k, true /* isResume */)
// Store the state file contents in a buffer for save-resume.
// There is no need to verify the state file, we just need the
// sandbox to continue running after save.
var buf bytes.Buffer
saveOpts.Destination = &buf
saveOpts.Save(k.SupervisorContext(), k, l.watchdog)
}
}
func getTargetForSaveRestore(l *Loader, f *os.File) func(k *kernel.Kernel) {
var once sync.Once
return func(k *kernel.Kernel) {
once.Do(func() {
saveOpts := getSaveOpts(l, k, false /* isResume */)
saveOpts.Destination = f
saveOpts.Save(k.SupervisorContext(), k, l.watchdog)
})
}
}
// EnableAutosave enables auto save restore in syscall tests.
func EnableAutosave(l *Loader, f *os.File, isResume bool) error {
var target func(k *kernel.Kernel)
if isResume {
target = getTargetForSaveResume(l)
} else {
target = getTargetForSaveRestore(l, f)
}
for _, table := range kernel.SyscallTables() {
sys, ok := strace.Lookup(table.OS, table.Arch)
if !ok {
continue
}
if err := configureInitSyscall(table, sys, "init_module", kernel.ExternalAfterEnable); err != nil {
return err
}
// Set external args to our closure above.
table.External = target
}
return nil
}
// configureInitSyscall sets the trigger for the S/R syscall tests and the callback
// method to be called after the sycall is executed.
func configureInitSyscall(table *kernel.SyscallTable, sys strace.SyscallMap, initSyscall string, syscallFlag uint32) error {
sl := make(map[uintptr]bool)
sysno, ok := sys.ConvertToSysno(initSyscall)
if !ok {
return fmt.Errorf("syscall %q not found", initSyscall)
}
sl[sysno] = true
log.Infof("sysno %v name %v", sysno, initSyscall)
table.FeatureEnable.Enable(syscallFlag, sl, false)
table.ExternalFilterBefore = func(*kernel.Task, uintptr, arch.SyscallArguments) bool {
return false
}
// Sets ExternalFilterAfter to true which calls the closure assigned to
// External after the syscall is executed.
table.ExternalFilterAfter = func(*kernel.Task, uintptr, arch.SyscallArguments) bool {
return true
}
return nil
}