tools: add syz-base-commit tool

The tool is aimed to facilitate debugging of the cases when the
blob-based base commit functionality did not work as expected or to
determine the missing remote trees.

1 files changed, 50 insertions, 0 deletions

diff --git a/tools/syz-base-commit/main.go b/tools/syz-base-commit/main.go
new file mode 100644
index 000000000..f5af3b075
--- /dev/null
+++ b/tools/syz-base-commit/main.go
@@ -0,0 +1,50 @@
+// 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.
+
+// syz-base-commit is a tool for debugging the blob-based base commit detection functionality.
+
+package main
+
+import (
+	"flag"
+	"log"
+	"os"
+
+	"github.com/google/syzkaller/pkg/debugtracer"
+	"github.com/google/syzkaller/pkg/tool"
+	"github.com/google/syzkaller/pkg/vcs"
+)
+
+var (
+	flagRepo = flag.String("sourcedir", "", "path to the Linux kernel repository")
+)
+
+func main() {
+	defer tool.Init()()
+	args := flag.Args()
+	if *flagRepo == "" || len(args) != 1 {
+		tool.Failf("expected format: syz-base-commit --sourcedir ./linux-repo some-patch.diff")
+	}
+	log.Printf("note: the tool runs much faster after a `git commit-graph write --reachable`")
+	diff, err := os.ReadFile(args[0])
+	if err != nil {
+		tool.Fail(err)
+	}
+	git := &vcs.Git{
+		Dir: *flagRepo,
+	}
+	commits, err := git.BaseForDiff(diff, &debugtracer.GenericTracer{
+		TraceWriter: os.Stderr,
+	})
+	if err != nil {
+		tool.Fail(err)
+	}
+	if len(commits) == 0 {
+		log.Printf("no suitable commits found!")
+		os.Exit(0)
+	}
+	log.Printf("found %d candidates:", len(commits))
+	for _, commit := range commits {
+		log.Printf("%+v", commit)
+	}
+}