pkg/cover: add gvisor support

2 files changed, 127 insertions, 0 deletions

diff --git a/pkg/cover/backend/backend.go b/pkg/cover/backend/backend.go
index 13ae3b400..eb9c1a2e5 100644
--- a/pkg/cover/backend/backend.go
+++ b/pkg/cover/backend/backend.go
@@ -52,5 +52,8 @@ func Make(target *targets.Target, vm, objDir, srcDir, buildDir string) (*Impl, e
 	if objDir == "" {
 		return nil, fmt.Errorf("kernel obj directory is not specified")
 	}
+	if vm == "gvisor" {
+		return makeGvisor(target, objDir, srcDir, buildDir)
+	}
 	return makeELF(target, objDir, srcDir, buildDir)
 }
diff --git a/pkg/cover/backend/gvisor.go b/pkg/cover/backend/gvisor.go
new file mode 100644
index 000000000..459ad60e9
--- /dev/null
+++ b/pkg/cover/backend/gvisor.go
@@ -0,0 +1,124 @@
+// Copyright 2020 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 backend
+
+import (
+	"bufio"
+	"fmt"
+	"path/filepath"
+	"regexp"
+	"strconv"
+
+	"github.com/google/syzkaller/pkg/osutil"
+	"github.com/google/syzkaller/sys/targets"
+)
+
+func makeGvisor(target *targets.Target, objDir, srcDir, buildDir string) (*Impl, error) {
+	// pkg/build stores runsc as 'image', but a local build will have it as 'runsc'.
+	bin := filepath.Join(objDir, "image")
+	if !osutil.IsExist(bin) {
+		bin = filepath.Join(objDir, "runsc")
+	}
+	frames, err := gvisorSymbolize(bin, srcDir)
+	if err != nil {
+		return nil, err
+	}
+	unitMap := make(map[string]*CompileUnit)
+	for _, frame := range frames {
+		unit := unitMap[frame.Name]
+		if unit == nil {
+			unit = &CompileUnit{
+				Name: frame.Name,
+				Path: frame.Path,
+			}
+			unitMap[frame.Name] = unit
+		}
+		unit.PCs = append(unit.PCs, frame.PC)
+	}
+	var units []*CompileUnit
+	for _, unit := range unitMap {
+		units = append(units, unit)
+	}
+	impl := &Impl{
+		Units:  units,
+		Frames: frames,
+		RestorePC: func(pc uint32) uint64 {
+			return uint64(pc)
+		},
+	}
+	return impl, nil
+}
+
+func gvisorSymbolize(bin, srcDir string) ([]Frame, error) {
+	cmd := osutil.Command(bin, "symbolize", "-all")
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return nil, err
+	}
+	defer stdout.Close()
+	if err := cmd.Start(); err != nil {
+		return nil, err
+	}
+	defer cmd.Wait()
+	var frames []Frame
+	s := bufio.NewScanner(stdout)
+	for s.Scan() {
+		frame, err := gvisorParseLine(s)
+		if err != nil {
+			return nil, err
+		}
+		frame.Path = filepath.Join(srcDir, frame.Name)
+		if !osutil.IsExist(frame.Path) {
+			// Try to locate auto-generated files.
+			// Note: some files are only present under some hashed path,
+			// e.g. bazel-out/k8-fastbuild-ST-4c64f0b3d5c7/bin/pkg/usermem/addr_range.go,
+			// it's unclear how we can locate them. In a local run that may be under objDir,
+			// but this is not the case for syz-ci.
+			path := filepath.Join(srcDir, "bazel-out", "k8-fastbuild", "bin", frame.Name)
+			if osutil.IsExist(path) {
+				frame.Path = path
+			}
+		}
+		frames = append(frames, frame)
+	}
+	if err := s.Err(); err != nil {
+		return nil, err
+	}
+	return frames, nil
+}
+
+func gvisorParseLine(s *bufio.Scanner) (Frame, error) {
+	pc, err := strconv.ParseUint(s.Text(), 0, 64)
+	if err != nil {
+		return Frame{}, fmt.Errorf("read pc %q, but no line info", pc)
+	}
+	if !s.Scan() {
+		return Frame{}, fmt.Errorf("read pc %q, but no line info", pc)
+	}
+	match := gvisorLineRe.FindStringSubmatch(s.Text())
+	if match == nil {
+		return Frame{}, fmt.Errorf("failed to parse line: %q", s.Text())
+	}
+	var ints [4]int
+	for i := range ints {
+		x, err := strconv.ParseUint(match[i+2], 0, 32)
+		if err != nil {
+			return Frame{}, fmt.Errorf("failed to parse number %q: %v", match[i+2], err)
+		}
+		ints[i] = int(x)
+	}
+	frame := Frame{
+		PC:   pc,
+		Name: match[1],
+		Range: Range{
+			StartLine: ints[0],
+			StartCol:  ints[1],
+			EndLine:   ints[2],
+			EndCol:    ints[3],
+		},
+	}
+	return frame, nil
+}
+
+var gvisorLineRe = regexp.MustCompile(`/gvisor/([^:]+):([0-9]+).([0-9]+),([0-9]+).([0-9]+)$`)