syzkaller/syz-manager/cover.go
2020-08-09 14:58:49 +02:00

93 lines
2.2 KiB
Go

// 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 (
"bufio"
"bytes"
"fmt"
"path/filepath"
"strconv"
"strings"
"sync"
"time"
"github.com/google/syzkaller/pkg/cover"
"github.com/google/syzkaller/pkg/osutil"
"github.com/google/syzkaller/sys/targets"
)
var (
initCoverOnce sync.Once
initCoverError error
initCoverVMOffset uint32
reportGenerator *cover.ReportGenerator
)
func initCover(target *targets.Target, kernelObj, kernelSrc, kernelBuildSrc string) error {
initCoverOnce.Do(func() {
if kernelObj == "" {
initCoverError = fmt.Errorf("kernel_obj is not specified")
return
}
vmlinux := filepath.Join(kernelObj, target.KernelObject)
reportGenerator, initCoverError = cover.MakeReportGenerator(target, vmlinux, kernelSrc, kernelBuildSrc)
if initCoverError != nil {
return
}
initCoverVMOffset, initCoverError = getVMOffset(target, vmlinux)
})
return initCoverError
}
func coverToPCs(target *targets.Target, cov []uint32) []uint64 {
pcs := make([]uint64, 0, len(cov))
for _, pc := range cov {
fullPC := cover.RestorePC(pc, initCoverVMOffset)
prevPC := cover.PreviousInstructionPC(target, fullPC)
pcs = append(pcs, prevPC)
}
return pcs
}
func getVMOffset(target *targets.Target, vmlinux string) (uint32, error) {
if target.OS == "freebsd" {
return 0xffffffff, nil
}
readelf := "readelf"
if target.Triple != "" {
readelf = target.Triple + "-" + readelf
}
out, err := osutil.RunCmd(time.Hour, "", readelf, "-SW", vmlinux)
if err != nil {
return 0, err
}
s := bufio.NewScanner(bytes.NewReader(out))
var addr uint32
for s.Scan() {
ln := s.Text()
pieces := strings.Fields(ln)
for i := 0; i < len(pieces); i++ {
if pieces[i] != "PROGBITS" {
continue
}
v, err := strconv.ParseUint("0x"+pieces[i+1], 0, 64)
if err != nil {
return 0, fmt.Errorf("failed to parse addr in readelf output: %v", err)
}
if v == 0 {
continue
}
v32 := (uint32)(v >> 32)
if addr == 0 {
addr = v32
}
if addr != v32 {
return 0, fmt.Errorf("different section offsets in a single binary")
}
}
}
return addr, nil
}