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// Copyright 2018 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 cover
import (
"fmt"
"sort"
"github.com/google/syzkaller/pkg/cover/backend"
"github.com/google/syzkaller/pkg/mgrconfig"
"github.com/google/syzkaller/pkg/vminfo"
"github.com/google/syzkaller/sys/targets"
"golang.org/x/exp/maps"
)
type ReportGenerator struct {
target *targets.Target
srcDir string
buildDir string
subsystem []mgrconfig.Subsystem
rawCoverEnabled bool
*backend.Impl
}
type Prog struct {
Sig string
Data string
PCs []uint64
}
func GetPCBase(cfg *mgrconfig.Config) (uint64, error) {
return backend.GetPCBase(cfg)
}
func MakeReportGenerator(cfg *mgrconfig.Config, modules []*vminfo.KernelModule) (*ReportGenerator, error) {
impl, err := backend.Make(cfg, modules)
if err != nil {
return nil, err
}
cfg.KernelSubsystem = append(cfg.KernelSubsystem, mgrconfig.Subsystem{
Name: "all",
Paths: []string{""},
})
rg := &ReportGenerator{
target: cfg.SysTarget,
srcDir: cfg.KernelSrc,
buildDir: cfg.KernelBuildSrc,
subsystem: cfg.KernelSubsystem,
rawCoverEnabled: cfg.RawCover,
Impl: impl,
}
return rg, nil
}
type file struct {
module string
filename string
lines map[int]line
functions []*function
covered []backend.Range
uncovered []backend.Range
totalPCs int
coveredPCs int
}
type function struct {
name string
pcs int
covered int
}
type line struct {
progCount map[int]bool // program indices that cover this line
progIndex int // example program index that covers this line
pcProgCount map[uint64]int // some lines have multiple BBs
}
type fileMap map[string]*file
func (rg *ReportGenerator) prepareFileMap(progs []Prog, force, debug bool) (fileMap, error) {
if err := rg.symbolizePCs(uniquePCs(progs...)); err != nil {
return nil, err
}
files := make(fileMap)
for _, unit := range rg.Units {
files[unit.Name] = &file{
module: unit.Module.Name,
filename: unit.Path,
lines: make(map[int]line),
totalPCs: len(unit.PCs),
}
}
pcToProgs := make(map[uint64]map[int]bool)
unmatchedPCs := make(map[uint64]bool)
for i, prog := range progs {
for _, pc := range prog.PCs {
if pcToProgs[pc] == nil {
pcToProgs[pc] = make(map[int]bool)
}
pcToProgs[pc][i] = true
if rg.PreciseCoverage && !contains(rg.CallbackPoints, pc) {
unmatchedPCs[pc] = true
}
}
}
err := rg.frame2line(files, pcToProgs, progs)
if err != nil {
return nil, err
}
// If the backend provided coverage callback locations for the binaries, use them to
// verify data returned by kcov.
if len(unmatchedPCs) > 0 && !force {
return nil, coverageCallbackMismatch(debug, len(pcToProgs), unmatchedPCs)
}
for _, unit := range rg.Units {
f := files[unit.Name]
for _, pc := range unit.PCs {
if pcToProgs[pc] != nil {
f.coveredPCs++
}
}
}
for _, s := range rg.Symbols {
fun := &function{
name: s.Name,
pcs: len(s.PCs),
}
for _, pc := range s.PCs {
if pcToProgs[pc] != nil {
fun.covered++
}
}
f := files[s.Unit.Name]
f.functions = append(f.functions, fun)
}
for _, f := range files {
sort.Slice(f.functions, func(i, j int) bool {
return f.functions[i].name < f.functions[j].name
})
}
return files, nil
}
func (rg *ReportGenerator) frame2line(files fileMap, pcToProgs map[uint64]map[int]bool, progs []Prog) error {
matchedPC := false
for _, frame := range rg.Frames {
if frame.StartLine < 0 {
continue
}
f := fileByFrame(files, frame)
ln := f.lines[frame.StartLine]
coveredBy := pcToProgs[frame.PC]
if len(coveredBy) == 0 {
f.uncovered = append(f.uncovered, frame.Range)
continue
}
// Covered frame.
f.covered = append(f.covered, frame.Range)
matchedPC = true
if ln.progCount == nil {
ln.progCount = make(map[int]bool)
ln.pcProgCount = make(map[uint64]int)
ln.progIndex = -1
}
for progIndex := range coveredBy {
ln.progCount[progIndex] = true
if ln.progIndex == -1 || len(progs[progIndex].Data) < len(progs[ln.progIndex].Data) {
ln.progIndex = progIndex
}
ln.pcProgCount[frame.PC]++
}
f.lines[frame.StartLine] = ln
}
if !matchedPC {
return fmt.Errorf("coverage doesn't match any coverage callbacks")
}
return nil
}
func contains(pcs []uint64, pc uint64) bool {
idx := sort.Search(len(pcs), func(i int) bool { return pcs[i] >= pc })
return idx < len(pcs) && pcs[idx] == pc
}
func coverageCallbackMismatch(debug bool, numPCs int, unmatchedPCs map[uint64]bool) error {
debugStr := ""
if debug {
debugStr += "\n\nUnmatched PCs:\n"
for pc := range unmatchedPCs {
debugStr += fmt.Sprintf("%x\n", pc)
}
}
return fmt.Errorf("%d out of %d PCs returned by kcov do not have matching coverage callbacks."+
" Check the discoverModules() code. Use ?force=1 to disable this message.%s",
len(unmatchedPCs), numPCs, debugStr)
}
func uniquePCs(progs ...Prog) []uint64 {
PCs := make(map[uint64]bool)
for _, p := range progs {
for _, pc := range p.PCs {
PCs[pc] = true
}
}
return maps.Keys(PCs)
}
func (rg *ReportGenerator) symbolizePCs(PCs []uint64) error {
if len(PCs) == 0 {
return fmt.Errorf("no coverage collected so far to symbolize")
}
if len(rg.Symbols) == 0 {
return nil
}
symbolize := make(map[*backend.Symbol]bool)
pcs := make(map[*vminfo.KernelModule][]uint64)
for _, pc := range PCs {
sym := rg.findSymbol(pc)
if sym == nil || sym.Symbolized || symbolize[sym] {
continue
}
symbolize[sym] = true
pcs[sym.Module] = append(pcs[sym.Module], sym.PCs...)
}
frames, err := rg.Symbolize(pcs)
if err != nil {
return err
}
rg.Frames = append(rg.Frames, frames...)
for sym := range symbolize {
sym.Symbolized = true
}
return nil
}
func fileByFrame(files map[string]*file, frame *backend.Frame) *file {
f := files[frame.Name]
if f == nil {
f = &file{
module: frame.Module.Name,
filename: frame.Path,
lines: make(map[int]line),
// Special mark for header files, if a file does not have coverage at all it is not shown.
totalPCs: 1,
coveredPCs: 1,
}
files[frame.Name] = f
}
return f
}
func (rg *ReportGenerator) findSymbol(pc uint64) *backend.Symbol {
idx := sort.Search(len(rg.Symbols), func(i int) bool {
return pc < rg.Symbols[i].End
})
if idx == len(rg.Symbols) {
return nil
}
s := rg.Symbols[idx]
if pc < s.Start || pc > s.End {
return nil
}
return s
}
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