mirror of
https://github.com/hanzoai/visor.git
synced 2026-09-24 17:04:14 +00:00
Ayush RanjanandgVisor bot
24f10937ab
The save/resume tests were writing the snapshot files to a bytes.Buffer, but the contents of the buffer were never used. This was unnecessarily consuming a lot of sandbox memory, potentially OOM-ing tests. Using io.Discard makes it clear that the output is not needed and avoids unnecessary buffering. PiperOrigin-RevId: 907042377
115 lines
3.5 KiB
Go
115 lines
3.5 KiB
Go
// Copyright 2024 The gVisor Authors.
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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 boot
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import (
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"fmt"
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"io"
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"gvisor.dev/gvisor/pkg/fd"
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"gvisor.dev/gvisor/pkg/log"
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"gvisor.dev/gvisor/pkg/sentry/arch"
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"gvisor.dev/gvisor/pkg/sentry/control"
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"gvisor.dev/gvisor/pkg/sentry/kernel"
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"gvisor.dev/gvisor/pkg/sentry/state"
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"gvisor.dev/gvisor/pkg/sentry/state/stateio"
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"gvisor.dev/gvisor/pkg/sentry/strace"
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"gvisor.dev/gvisor/pkg/sync"
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)
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func getTargetForSaveResume(l *Loader) func(k *kernel.Kernel) {
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return func(k *kernel.Kernel) {
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// Discard the state file contents for save-resume. There is no need to
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// verify the state file, we just need the sandbox to continue running
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// after save.
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saveOpts := state.SaveOpts{
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Autosave: true,
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Resume: true,
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Destination: io.Discard,
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}
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defer saveOpts.Close()
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l.saveWithOpts(&saveOpts, &control.SaveRestoreExecOpts{})
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}
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}
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func getTargetForSaveRestore(l *Loader, files []*fd.FD) func(k *kernel.Kernel) {
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if len(files) != 1 && len(files) != 3 {
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panic(fmt.Sprintf("Unexpected number of files: %v", len(files)))
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}
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var once sync.Once
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return func(k *kernel.Kernel) {
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once.Do(func() {
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saveOpts := state.SaveOpts{
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Autosave: true,
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Resume: false,
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Destination: files[0],
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}
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if len(files) == 3 {
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saveOpts.PagesMetadata = stateio.NewBufioWriteCloser(files[1])
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saveOpts.PagesFile = stateio.NewPagesFileFDWriterDefault(int32(files[2].Release()))
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}
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defer saveOpts.Close()
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l.saveWithOpts(&saveOpts, &control.SaveRestoreExecOpts{})
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})
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}
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}
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// enableAutosave enables auto save restore in syscall tests.
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func enableAutosave(l *Loader, isResume bool, files []*fd.FD) error {
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var target func(k *kernel.Kernel)
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if isResume {
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target = getTargetForSaveResume(l)
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} else {
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target = getTargetForSaveRestore(l, files)
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}
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for _, table := range kernel.SyscallTables() {
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sys, ok := strace.Lookup(table.OS, table.Arch)
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if !ok {
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continue
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}
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if err := configureInitSyscall(table, sys, "init_module", kernel.ExternalAfterEnable); err != nil {
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return err
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}
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// Set external args to our closure above.
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table.External = target
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}
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return nil
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}
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// configureInitSyscall sets the trigger for the S/R syscall tests and the callback
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// method to be called after the sycall is executed.
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func configureInitSyscall(table *kernel.SyscallTable, sys strace.SyscallMap, initSyscall string, syscallFlag uint32) error {
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sl := make(map[uintptr]bool)
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sysno, ok := sys.ConvertToSysno(initSyscall)
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if !ok {
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return fmt.Errorf("syscall %q not found", initSyscall)
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}
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sl[sysno] = true
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log.Infof("sysno %v name %v", sysno, initSyscall)
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table.FeatureEnable.Enable(syscallFlag, sl, false)
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table.ExternalFilterBefore = func(*kernel.Task, uintptr, arch.SyscallArguments) bool {
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return false
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}
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// Sets ExternalFilterAfter to true which calls the closure assigned to
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// External after the syscall is executed.
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table.ExternalFilterAfter = func(*kernel.Task, uintptr, arch.SyscallArguments) bool {
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return true
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}
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return nil
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}
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