From 96ff84efe96135909f870cd105d034ff9bf77c05 Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@google.com>
Date: Thu, 20 Jan 2022 15:39:18 +0100
Subject: pkg/db: treat deserialization errors as soft

corpus.db may get corrupted on an unexpected reset, etc.
Commit a254b0f5 ("pkg/db: properly handle errors when loading a DB")
made these errors fatal and manager never recovers on its own.
Restore the previous behavior when we still recovered some records from the db.
But (1) ensure that the file is at least writable and (2) add tests.
---
 pkg/db/db_test.go | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 54 insertions(+), 1 deletion(-)

(limited to 'pkg/db/db_test.go')

diff --git a/pkg/db/db_test.go b/pkg/db/db_test.go
index 71b93fd64..7ff69b2b7 100644
--- a/pkg/db/db_test.go
+++ b/pkg/db/db_test.go
@@ -130,8 +130,61 @@ func TestOpenInvalid(t *testing.T) {
 	if _, err := f.Write([]byte(`some invalid data`)); err != nil {
 		t.Error(err)
 	}
-	if _, err := Open(f.Name()); err == nil {
+	if db, err := Open(f.Name()); err == nil {
 		t.Fatal("opened invalid db")
+	} else if db == nil {
+		t.Fatal("db is nil")
+	}
+}
+
+func TestOpenInaccessible(t *testing.T) {
+	f, err := ioutil.TempFile("", "syz-db-test")
+	if err != nil {
+		t.Error(err)
+	}
+	f.Close()
+	os.Chmod(f.Name(), 0)
+	defer os.Chmod(f.Name(), 0777)
+	defer os.Remove(f.Name())
+	if db, err := Open(f.Name()); err == nil {
+		t.Fatal("opened inaccessible db")
+	} else if db != nil {
+		t.Fatal("db is not nil")
+	}
+}
+
+func TestOpenCorrupted(t *testing.T) {
+	fn := tempFile(t)
+	defer os.Remove(fn)
+	db, err := Open(fn)
+	if err != nil {
+		t.Fatalf("failed to open db: %v", err)
+	}
+	// Write 1000 records, then wipe half of the file and test that we
+	// (1) get an error, (2) still get 450-550 records.
+	for i := 0; i < 1000; i++ {
+		db.Save(fmt.Sprintf("%v", i), []byte{byte(i)}, 0)
+	}
+	if err := db.Flush(); err != nil {
+		t.Fatalf("failed to flush db: %v", err)
+	}
+	data, err := ioutil.ReadFile(fn)
+	if err != nil {
+		t.Fatalf("failed to read db: %v", err)
+	}
+	for i := len(data) / 2; i < len(data); i++ {
+		data[i] = 0
+	}
+	if err := osutil.WriteFile(fn, data); err != nil {
+		t.Fatalf("failed to write db: %v", err)
+	}
+	db, err = Open(fn)
+	if err == nil {
+		t.Fatalf("no error for corrutped db")
+	}
+	t.Logf("records %v, error: %v", len(db.Records), err)
+	if len(db.Records) < 450 || len(db.Records) > 550 {
+		t.Fatalf("wrong record count: %v", len(db.Records))
 	}
 }
 
-- 
cgit mrf-deployment