1 files changed, 129 insertions, 0 deletions
diff --git a/master/persistent.go b/master/persistent.go
new file mode 100644
index 000000000..12f4bbdc8
--- /dev/null
+++ b/master/persistent.go
@@ -0,0 +1,129 @@
+// Copyright 2015 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 main
+
+import (
+	"crypto/sha1"
+	"encoding/hex"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"path/filepath"
+)
+
+type Sig [sha1.Size]byte
+
+// PersistentSet is a set of binary blobs with a persistent mirror on disk.
+type PersistentSet struct {
+	dir string
+	m   map[Sig][]byte
+	a   [][]byte
+}
+
+func hash(data []byte) Sig {
+	return Sig(sha1.Sum(data))
+}
+
+func newPersistentSet(dir string, verify func(data []byte) bool) *PersistentSet {
+	ps := &PersistentSet{
+		dir: dir,
+		m:   make(map[Sig][]byte),
+	}
+	os.MkdirAll(dir, 0770)
+	filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			log.Fatalf("error during dir walk: %v\n", err)
+		}
+		if info.IsDir() {
+			return nil
+		}
+		data, err := ioutil.ReadFile(path)
+		if err != nil {
+			log.Fatalf("error during file read: %v\n", err)
+			return nil
+		}
+		sig := hash(data)
+		if _, ok := ps.m[sig]; ok {
+			return nil
+		}
+		name := info.Name()
+		if len(data) == 0 {
+			// This can happen is master runs on machine-under-test,
+			// and it has crashed midway.
+			log.Printf("removing empty file %v", name)
+			os.Remove(path)
+			return nil
+		}
+		const hexLen = 2 * sha1.Size
+		if len(name) > hexLen+1 && isHexString(name[:hexLen]) && name[hexLen] == '.' {
+			return nil // description file
+		}
+		if len(name) != hexLen || !isHexString(name) {
+			log.Fatalf("unknown file in persistent dir %v: %v", dir, name)
+		}
+		if verify != nil && !verify(data) {
+			os.Remove(path)
+			return nil
+		}
+		if name != hex.EncodeToString(sig[:]) {
+			log.Printf("bad hash in persistent dir %v for file %v, expect %v", dir, name, hex.EncodeToString(sig[:]))
+			if err := ioutil.WriteFile(filepath.Join(ps.dir, hex.EncodeToString(sig[:])), data, 0660); err != nil {
+				log.Fatalf("failed to write file: %v", err)
+			}
+			os.Remove(path)
+		}
+		ps.m[sig] = data
+		ps.a = append(ps.a, data)
+		return nil
+	})
+	return ps
+}
+
+func isHexString(s string) bool {
+	for _, v := range []byte(s) {
+		if v >= '0' && v <= '9' || v >= 'a' && v <= 'f' {
+			continue
+		}
+		return false
+	}
+	return true
+}
+
+func (ps *PersistentSet) add(data []byte) bool {
+	sig := hash(data)
+	if _, ok := ps.m[sig]; ok {
+		return false
+	}
+	data = append([]byte{}, data...)
+	ps.m[sig] = data
+	ps.a = append(ps.a, data)
+	fname := filepath.Join(ps.dir, hex.EncodeToString(sig[:]))
+	if err := ioutil.WriteFile(fname, data, 0660); err != nil {
+		log.Fatalf("failed to write file: %v", err)
+	}
+	return true
+}
+
+// addDescription creates a complementary to data file on disk.
+func (ps *PersistentSet) addDescription(data []byte, desc []byte, typ string) {
+	sig := hash(data)
+	fname := filepath.Join(ps.dir, fmt.Sprintf("%v.%v", hex.EncodeToString(sig[:]), typ))
+	if err := ioutil.WriteFile(fname, desc, 0660); err != nil {
+		log.Fatalf("failed to write file: %v", err)
+	}
+}
+
+func (ps *PersistentSet) minimize(set map[string]bool) {
+	ps.a = nil
+	for sig, data := range ps.m {
+		s := hex.EncodeToString(sig[:])
+		if set[s] {
+			ps.a = append(ps.a, data)
+		} else {
+			delete(ps.m, sig)
+			os.Remove(filepath.Join(ps.dir, s))
+		}
+	}
+}