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// Copyright 2017 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
//go:generate bash -c "echo -en '// AUTOGENERATED FILE\n\n' > linux_generated.go"
//go:generate bash -c "echo -en 'package build\n\n' >> linux_generated.go"
//go:generate bash -c "echo -en 'const createImageScript = `#!/bin/bash\n' >> linux_generated.go"
//go:generate bash -c "cat ../../tools/create-gce-image.sh | grep -v '#' >> linux_generated.go"
//go:generate bash -c "echo -en '`\n\n' >> linux_generated.go"
package build
import (
"bytes"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"runtime"
"strconv"
"time"
"github.com/google/syzkaller/pkg/osutil"
)
type linux struct{}
func (linux linux) build(targetArch, vmType, kernelDir, outputDir, compiler, userspaceDir,
cmdlineFile, sysctlFile string, config []byte) error {
if err := linux.buildKernel(kernelDir, outputDir, compiler, config); err != nil {
return err
}
if err := linux.createImage(vmType, kernelDir, outputDir, userspaceDir, cmdlineFile, sysctlFile); err != nil {
return err
}
return nil
}
func (linux) buildKernel(kernelDir, outputDir, compiler string, config []byte) error {
configFile := filepath.Join(kernelDir, ".config")
if err := osutil.WriteFile(configFile, config); err != nil {
return fmt.Errorf("failed to write config file: %v", err)
}
if err := osutil.SandboxChown(configFile); err != nil {
return err
}
// One would expect olddefconfig here, but olddefconfig is not present in v3.6 and below.
// oldconfig is the same as olddefconfig if stdin is not set.
// Note: passing in compiler is important since 4.17 (at the very least it's noted in the config).
cmd := osutil.Command("make", "oldconfig", "CC="+compiler)
if err := osutil.Sandbox(cmd, true, true); err != nil {
return err
}
cmd.Dir = kernelDir
if _, err := osutil.Run(10*time.Minute, cmd); err != nil {
return err
}
// Write updated kernel config early, so that it's captured on build failures.
outputConfig := filepath.Join(outputDir, "kernel.config")
if err := osutil.CopyFile(configFile, outputConfig); err != nil {
return err
}
// We build only bzImage as we currently don't use modules.
cpu := strconv.Itoa(runtime.NumCPU())
cmd = osutil.Command("make", "bzImage", "-j", cpu, "CC="+compiler)
if err := osutil.Sandbox(cmd, true, true); err != nil {
return err
}
cmd.Dir = kernelDir
if _, err := osutil.Run(time.Hour, cmd); err != nil {
return extractRootCause(err)
}
vmlinux := filepath.Join(kernelDir, "vmlinux")
outputVmlinux := filepath.Join(outputDir, "obj", "vmlinux")
if err := osutil.Rename(vmlinux, outputVmlinux); err != nil {
return fmt.Errorf("failed to rename vmlinux: %v", err)
}
return nil
}
func (linux) createImage(vmType, kernelDir, outputDir, userspaceDir, cmdlineFile, sysctlFile string) error {
tempDir, err := ioutil.TempDir("", "syz-build")
if err != nil {
return err
}
defer os.RemoveAll(tempDir)
scriptFile := filepath.Join(tempDir, "create.sh")
if err := osutil.WriteExecFile(scriptFile, []byte(createImageScript)); err != nil {
return fmt.Errorf("failed to write script file: %v", err)
}
bzImage := filepath.Join(kernelDir, filepath.FromSlash("arch/x86/boot/bzImage"))
cmd := osutil.Command(scriptFile, userspaceDir, bzImage)
cmd.Dir = tempDir
cmd.Env = append([]string{}, os.Environ()...)
cmd.Env = append(cmd.Env,
"SYZ_VM_TYPE="+vmType,
"SYZ_CMDLINE_FILE="+osutil.Abs(cmdlineFile),
"SYZ_SYSCTL_FILE="+osutil.Abs(sysctlFile),
)
if _, err = osutil.Run(time.Hour, cmd); err != nil {
return fmt.Errorf("image build failed: %v", err)
}
// Note: we use CopyFile instead of Rename because src and dst can be on different filesystems.
imageFile := filepath.Join(outputDir, "image")
if err := osutil.CopyFile(filepath.Join(tempDir, "disk.raw"), imageFile); err != nil {
return err
}
keyFile := filepath.Join(outputDir, "key")
if err := osutil.CopyFile(filepath.Join(tempDir, "key"), keyFile); err != nil {
return err
}
if err := os.Chmod(keyFile, 0600); err != nil {
return err
}
return nil
}
func (linux) clean(kernelDir string) error {
cpu := strconv.Itoa(runtime.NumCPU())
cmd := osutil.Command("make", "distclean", "-j", cpu)
if err := osutil.Sandbox(cmd, true, true); err != nil {
return err
}
cmd.Dir = kernelDir
_, err := osutil.Run(10*time.Minute, cmd)
return err
}
func extractRootCause(err error) error {
verr, ok := err.(*osutil.VerboseError)
if !ok {
return err
}
var cause []byte
for _, line := range bytes.Split(verr.Output, []byte{'\n'}) {
for _, pattern := range buildFailureCauses {
if pattern.weak && cause != nil {
continue
}
if bytes.Contains(line, pattern.pattern) {
cause = line
break
}
}
}
if cause != nil {
verr.Title = string(cause)
}
return KernelBuildError{verr}
}
type buildFailureCause struct {
pattern []byte
weak bool
}
var buildFailureCauses = [...]buildFailureCause{
{pattern: []byte(": error: ")},
{pattern: []byte(": fatal error: ")},
{pattern: []byte(": undefined reference to")},
{weak: true, pattern: []byte(": final link failed: ")},
{weak: true, pattern: []byte("collect2: error: ")},
}
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