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// Copyright 2025 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 kfuzztestmanager
import (
"context"
"fmt"
"math/rand"
"os"
"slices"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/google/syzkaller/pkg/corpus"
"github.com/google/syzkaller/pkg/fuzzer"
"github.com/google/syzkaller/pkg/fuzzer/queue"
"github.com/google/syzkaller/pkg/kfuzztest"
executor "github.com/google/syzkaller/pkg/kfuzztest-executor"
"github.com/google/syzkaller/pkg/log"
"github.com/google/syzkaller/pkg/mgrconfig"
"github.com/google/syzkaller/pkg/stat"
"github.com/google/syzkaller/prog"
"github.com/google/syzkaller/sys/targets"
)
type kFuzzTestManager struct {
fuzzer atomic.Pointer[fuzzer.Fuzzer]
source queue.Source
target *prog.Target
config Config
}
type Config struct {
VmlinuxPath string
Cooldown uint32
DisplayInterval uint32
NumThreads int
EnabledTargets []string
}
func NewKFuzzTestManager(ctx context.Context, cfg Config) (*kFuzzTestManager, error) {
var mgr kFuzzTestManager
target, err := prog.GetTarget(targets.Linux, targets.AMD64)
if err != nil {
return nil, err
}
log.Logf(0, "extracting KFuzzTest targets from \"%s\" (this will take a few seconds)", cfg.VmlinuxPath)
calls, err := kfuzztest.ActivateKFuzzTargets(target, cfg.VmlinuxPath)
if err != nil {
return nil, err
}
enabledCalls := make(map[*prog.Syscall]bool)
for _, call := range calls {
enabledCalls[call] = true
}
// Disable all calls that weren't explicitly enabled.
if len(cfg.EnabledTargets) > 0 {
enabledMap := make(map[string]bool)
for _, enabled := range cfg.EnabledTargets {
enabledMap[enabled] = true
}
for syscall := range enabledCalls {
testName, isSyzKFuzzTest := kfuzztest.GetTestName(syscall)
_, isEnabled := enabledMap[testName]
if isSyzKFuzzTest && syscall.Attrs.KFuzzTest && isEnabled {
enabledMap[testName] = true
} else {
delete(enabledCalls, syscall)
}
}
}
dispDiscoveredTargets := func() string {
var builder strings.Builder
totalEnabled := 0
builder.WriteString("enabled KFuzzTest targets: [\n")
for targ, enabled := range enabledCalls {
if enabled {
fmt.Fprintf(&builder, "\t%s,\n", targ.Name)
totalEnabled++
}
}
fmt.Fprintf(&builder, "]\ntotal = %d\n", totalEnabled)
return builder.String()
}
log.Logf(0, "%s", dispDiscoveredTargets())
corpus := corpus.NewCorpus(ctx)
rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
fuzzerObj := fuzzer.NewFuzzer(ctx, &fuzzer.Config{
Corpus: corpus,
Snapshot: false,
Coverage: true,
FaultInjection: false,
Comparisons: false,
Collide: false,
EnabledCalls: enabledCalls,
NoMutateCalls: make(map[int]bool),
FetchRawCover: false,
Logf: func(level int, msg string, args ...any) {
if level != 0 {
return
}
log.Logf(level, msg, args...)
},
NewInputFilter: func(call string) bool {
// Don't filter anything.
return true
},
}, rnd, target)
// TODO: Sufficient for startup, but not ideal that we are passing a
// manager config here. Would require changes to pkg/fuzzer if we wanted to
// avoid the dependency.
execOpts := fuzzer.DefaultExecOpts(&mgrconfig.Config{Sandbox: "none"}, 0, false)
mgr.target = target
mgr.fuzzer.Store(fuzzerObj)
mgr.source = queue.DefaultOpts(fuzzerObj, execOpts)
mgr.config = cfg
return &mgr, nil
}
func (mgr *kFuzzTestManager) Run(ctx context.Context) {
var wg sync.WaitGroup
// Launches the executor threads.
executor := executor.NewKFuzzTestExecutor(ctx, mgr.config.NumThreads, mgr.config.Cooldown)
// Display logs periodically.
display := func() {
defer wg.Done()
mgr.displayLoop(ctx)
}
wg.Add(1)
go display()
FuzzLoop:
for {
select {
case <-ctx.Done():
break FuzzLoop
default:
}
req := mgr.source.Next()
if req == nil {
continue
}
executor.Submit(req)
}
log.Log(0, "fuzzing finished, shutting down executor")
executor.Shutdown()
wg.Wait()
const filepath string = "pcs.out"
log.Logf(0, "writing PCs out to \"%s\"", filepath)
if err := mgr.writePCs(filepath); err != nil {
log.Logf(0, "failed to write PCs: %v", err)
}
log.Log(0, "KFuzzTest manager exited")
}
func (mgr *kFuzzTestManager) writePCs(filepath string) error {
pcs := mgr.fuzzer.Load().Config.Corpus.Cover()
slices.Sort(pcs)
var builder strings.Builder
for _, pc := range pcs {
fmt.Fprintf(&builder, "0x%x\n", pc)
}
return os.WriteFile(filepath, []byte(builder.String()), 0644)
}
func (mgr *kFuzzTestManager) displayLoop(ctx context.Context) {
ticker := time.NewTicker(time.Duration(mgr.config.DisplayInterval) * time.Second)
defer ticker.Stop()
for {
var buf strings.Builder
select {
case <-ctx.Done():
return
case <-ticker.C:
for _, stat := range stat.Collect(stat.Console) {
fmt.Fprintf(&buf, "%v=%v ", stat.Name, stat.Value)
}
log.Log(0, buf.String())
}
}
}
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