pkg/build: move from pkg/kernel

Rename pkg/kernel to pkg/build and prepare for multi-OS support.

1 files changed, 162 insertions, 0 deletions

diff --git a/pkg/build/linux.go b/pkg/build/linux.go
new file mode 100644
index 000000000..e8c2d0f6d
--- /dev/null
+++ b/pkg/build/linux.go
@@ -0,0 +1,162 @@
+// 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"
+	"strings"
+	"time"
+
+	"github.com/google/syzkaller/pkg/osutil"
+)
+
+func Build(dir, compiler string, config []byte) error {
+	configFile := filepath.Join(dir, ".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 = dir
+	if _, err := osutil.Run(10*time.Minute, cmd); 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 = dir
+	// Build of a large kernel can take a while on a 1 CPU VM.
+	if _, err := osutil.Run(3*time.Hour, cmd); err != nil {
+		return extractRootCause(err)
+	}
+	return nil
+}
+
+func Clean(dir 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 = dir
+	_, err := osutil.Run(10*time.Minute, cmd)
+	return err
+}
+
+// CreateImage creates a disk image that is suitable for syzkaller.
+// Kernel is taken from kernelDir, userspace system is taken from userspaceDir.
+// If cmdlineFile is not empty, contents of the file are appended to the kernel command line.
+// If sysctlFile is not empty, contents of the file are appended to the image /etc/sysctl.conf.
+// Produces image and root ssh key in the specified files.
+func CreateImage(targetOS, targetArch, vmType, kernelDir, userspaceDir, cmdlineFile, sysctlFile,
+	image, sshkey string) error {
+	if targetOS != "linux" || targetArch != "amd64" {
+		return fmt.Errorf("only linux/amd64 is supported")
+	}
+	if vmType != "qemu" && vmType != "gce" {
+		return fmt.Errorf("images can be built only for qemu/gce machines")
+	}
+	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.
+	if err := osutil.CopyFile(filepath.Join(tempDir, "disk.raw"), image); err != nil {
+		return err
+	}
+	if err := osutil.CopyFile(filepath.Join(tempDir, "key"), sshkey); err != nil {
+		return err
+	}
+	if err := os.Chmod(sshkey, 0600); err != nil {
+		return err
+	}
+	return nil
+}
+
+func CompilerIdentity(compiler string) (string, error) {
+	output, err := osutil.RunCmd(time.Minute, "", compiler, "--version")
+	if err != nil {
+		return "", err
+	}
+	if len(output) == 0 {
+		return "", fmt.Errorf("no output from compiler --version")
+	}
+	return strings.Split(string(output), "\n")[0], nil
+}
+
+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 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: ")},
+}