tools: add syz-expand

The syz-expand tools allows to parse a program and print it including all
the default values. This is mainly useful for debugging, like doing manual
program modifications while trying to come up with a reproducer for some
particular kernel behavior.

1 files changed, 52 insertions, 0 deletions

diff --git a/tools/syz-expand/expand.go b/tools/syz-expand/expand.go
new file mode 100644
index 000000000..d90053d9d
--- /dev/null
+++ b/tools/syz-expand/expand.go
@@ -0,0 +1,52 @@
+// 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.
+
+// Parses a program and prints it including all default values.
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"runtime"
+
+	"github.com/google/syzkaller/prog"
+	_ "github.com/google/syzkaller/sys"
+)
+
+var (
+	flagOS     = flag.String("os", runtime.GOOS, "target os")
+	flagArch   = flag.String("arch", runtime.GOARCH, "target arch")
+	flagProg   = flag.String("prog", "", "file with program to expand")
+	flagStrict = flag.Bool("strict", false, "parse input program in strict mode")
+)
+
+func main() {
+	flag.Parse()
+	if *flagProg == "" {
+		flag.Usage()
+		os.Exit(1)
+	}
+	target, err := prog.GetTarget(*flagOS, *flagArch)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%v", err)
+		os.Exit(1)
+	}
+	data, err := ioutil.ReadFile(*flagProg)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "failed to read prog file: %v\n", err)
+		os.Exit(1)
+	}
+	mode := prog.NonStrict
+	if *flagStrict {
+		mode = prog.Strict
+	}
+	p, err := target.Deserialize(data, mode)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "failed to deserialize the program: %v\n", err)
+		os.Exit(1)
+	}
+	fmt.Printf("%s", p.SerializeVerbose())
+}