pkg/build: add freebsd

For now we must assume that we're building on FreeBSD; cross-compilation
support isn't quite there yet.

During a build, we first build an updated kernel toolchain if required,
generate a custom kernel configuration file with KCOV enabled, and build
a new kernel.  (When running on the custom kernel, "uname -i" will print
"SYZKALLER" rather than "GENERIC".)  Then, the image is mounted under a
tmpdir and we install the custom kernel to /boot/kernel.

2 files changed, 88 insertions, 0 deletions

diff --git a/pkg/build/build.go b/pkg/build/build.go
index 620ac5e07..44ea043a8 100644
--- a/pkg/build/build.go
+++ b/pkg/build/build.go
@@ -76,6 +76,7 @@ func getBuilder(targetOS, targetArch, vmType string) (builder, error) {
 		{"akaros", "amd64", []string{"qemu"}, akaros{}},
 		{"openbsd", "amd64", []string{"gce", "vmm"}, openbsd{}},
 		{"netbsd", "amd64", []string{"gce", "qemu"}, netbsd{}},
+		{"freebsd", "amd64", []string{"gce", "qemu"}, freebsd{}},
 	}
 	for _, s := range supported {
 		if targetOS == s.OS && targetArch == s.arch {
diff --git a/pkg/build/freebsd.go b/pkg/build/freebsd.go
new file mode 100644
index 000000000..babbfe07c
--- /dev/null
+++ b/pkg/build/freebsd.go
@@ -0,0 +1,87 @@
+// Copyright 2019 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.
+
+package build
+
+import (
+	"fmt"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/google/syzkaller/pkg/osutil"
+)
+
+type freebsd struct{}
+
+func (ctx freebsd) build(targetArch, vmType, kernelDir, outputDir, compiler, userspaceDir,
+	cmdlineFile, sysctlFile string, config []byte) error {
+	confFile := fmt.Sprintf("%v/sys/%v/conf/SYZKALLER", kernelDir, targetArch)
+
+	if config == nil {
+		config = []byte(`
+include "./GENERIC"
+
+ident		SYZKALLER
+options 	COVERAGE
+options 	KCOV
+`)
+	}
+	if err := osutil.WriteFile(confFile, config); err != nil {
+		return err
+	}
+
+	objDir := filepath.Join(outputDir, "obj")
+	if err := ctx.make(kernelDir, objDir, "kernel-toolchain"); err != nil {
+		return err
+	}
+	if err := ctx.make(kernelDir, objDir, "buildkernel", "KERNCONF=SYZKALLER"); err != nil {
+		return err
+	}
+
+	for _, s := range []struct{ dir, src, dst string }{
+		{userspaceDir, "image", "image"},
+		{userspaceDir, "key", "key"},
+	} {
+		fullSrc := filepath.Join(s.dir, s.src)
+		fullDst := filepath.Join(outputDir, s.dst)
+		if err := osutil.CopyFile(fullSrc, fullDst); err != nil {
+			return fmt.Errorf("failed to copy %v -> %v: %v", fullSrc, fullDst, err)
+		}
+	}
+
+	script := fmt.Sprintf(`
+set -eux
+md=$(sudo mdconfig -a -t vnode image)
+tmpdir=$(mktemp -d)
+sudo mount /dev/${md}p3 $tmpdir
+
+sudo MAKEOBJDIRPREFIX=$(pwd)/obj make -C %s installkernel KERNCONF=SYZKALLER DESTDIR=$tmpdir
+
+sudo umount $tmpdir
+sudo mdconfig -d -u ${md#md}
+`, kernelDir)
+
+	if debugOut, err := osutil.RunCmd(10*time.Minute, outputDir, "/bin/sh", "-c", script); err != nil {
+		return fmt.Errorf("error copying kernel: %v\n%v", err, debugOut)
+	}
+	return nil
+}
+
+func (ctx freebsd) clean(kernelDir, targetArch string) error {
+	// Builds are non-incremental for now, so we don't need to do anything here.
+	return nil
+}
+
+func (ctx freebsd) make(kernelDir string, objDir string, makeArgs ...string) error {
+	args := append([]string{
+		fmt.Sprintf("MAKEOBJDIRPREFIX=%v", objDir),
+		"make",
+		"-C", kernelDir,
+		"-j", strconv.Itoa(runtime.NumCPU()),
+	}, makeArgs...)
+	_, err := osutil.RunCmd(3*time.Hour, kernelDir, "sh", "-c", strings.Join(args, " "))
+	return err
+}