Your IP : 172.28.240.42
// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package coverage
import (
"crypto/md5"
"fmt"
"internal/coverage"
"internal/coverage/encodecounter"
"internal/coverage/encodemeta"
"internal/coverage/rtcov"
"io"
"os"
"path/filepath"
"reflect"
"runtime"
"strconv"
"sync/atomic"
"time"
"unsafe"
)
// This file contains functions that support the writing of data files
// emitted at the end of code coverage testing runs, from instrumented
// executables.
// getCovMetaList returns a list of meta-data blobs registered
// for the currently executing instrumented program. It is defined in the
// runtime.
func getCovMetaList() []rtcov.CovMetaBlob
// getCovCounterList returns a list of counter-data blobs registered
// for the currently executing instrumented program. It is defined in the
// runtime.
func getCovCounterList() []rtcov.CovCounterBlob
// getCovPkgMap returns a map storing the remapped package IDs for
// hard-coded runtime packages (see internal/coverage/pkgid.go for
// more on why hard-coded package IDs are needed). This function
// is defined in the runtime.
func getCovPkgMap() map[int]int
// emitState holds useful state information during the emit process.
//
// When an instrumented program finishes execution and starts the
// process of writing out coverage data, it's possible that an
// existing meta-data file already exists in the output directory. In
// this case openOutputFiles() below will leave the 'mf' field below
// as nil. If a new meta-data file is needed, field 'mfname' will be
// the final desired path of the meta file, 'mftmp' will be a
// temporary file, and 'mf' will be an open os.File pointer for
// 'mftmp'. The meta-data file payload will be written to 'mf', the
// temp file will be then closed and renamed (from 'mftmp' to
// 'mfname'), so as to insure that the meta-data file is created
// atomically; we want this so that things work smoothly in cases
// where there are several instances of a given instrumented program
// all terminating at the same time and trying to create meta-data
// files simultaneously.
//
// For counter data files there is less chance of a collision, hence
// the openOutputFiles() stores the counter data file in 'cfname' and
// then places the *io.File into 'cf'.
type emitState struct {
mfname string // path of final meta-data output file
mftmp string // path to meta-data temp file (if needed)
mf *os.File // open os.File for meta-data temp file
cfname string // path of final counter data file
cftmp string // path to counter data temp file
cf *os.File // open os.File for counter data file
outdir string // output directory
// List of meta-data symbols obtained from the runtime
metalist []rtcov.CovMetaBlob
// List of counter-data symbols obtained from the runtime
counterlist []rtcov.CovCounterBlob
// Table to use for remapping hard-coded pkg ids.
pkgmap map[int]int
// emit debug trace output
debug bool
}
var (
// finalHash is computed at init time from the list of meta-data
// symbols registered during init. It is used both for writing the
// meta-data file and counter-data files.
finalHash [16]byte
// Set to true when we've computed finalHash + finalMetaLen.
finalHashComputed bool
// Total meta-data length.
finalMetaLen uint64
// Records whether we've already attempted to write meta-data.
metaDataEmitAttempted bool
// Counter mode for this instrumented program run.
cmode coverage.CounterMode
// Counter granularity for this instrumented program run.
cgran coverage.CounterGranularity
// Cached value of GOCOVERDIR environment variable.
goCoverDir string
// Copy of os.Args made at init time, converted into map format.
capturedOsArgs map[string]string
// Flag used in tests to signal that coverage data already written.
covProfileAlreadyEmitted bool
)
// fileType is used to select between counter-data files and
// meta-data files.
type fileType int
const (
noFile = 1 << iota
metaDataFile
counterDataFile
)
// emitMetaData emits the meta-data output file for this coverage run.
// This entry point is intended to be invoked by the compiler from
// an instrumented program's main package init func.
func emitMetaData() {
if covProfileAlreadyEmitted {
return
}
ml, err := prepareForMetaEmit()
if err != nil {
fmt.Fprintf(os.Stderr, "error: coverage meta-data prep failed: %v\n", err)
if os.Getenv("GOCOVERDEBUG") != "" {
panic("meta-data write failure")
}
}
if len(ml) == 0 {
fmt.Fprintf(os.Stderr, "program not built with -cover\n")
return
}
goCoverDir = os.Getenv("GOCOVERDIR")
if goCoverDir == "" {
fmt.Fprintf(os.Stderr, "warning: GOCOVERDIR not set, no coverage data emitted\n")
return
}
if err := emitMetaDataToDirectory(goCoverDir, ml); err != nil {
fmt.Fprintf(os.Stderr, "error: coverage meta-data emit failed: %v\n", err)
if os.Getenv("GOCOVERDEBUG") != "" {
panic("meta-data write failure")
}
}
}
func modeClash(m coverage.CounterMode) bool {
if m == coverage.CtrModeRegOnly || m == coverage.CtrModeTestMain {
return false
}
if cmode == coverage.CtrModeInvalid {
cmode = m
return false
}
return cmode != m
}
func granClash(g coverage.CounterGranularity) bool {
if cgran == coverage.CtrGranularityInvalid {
cgran = g
return false
}
return cgran != g
}
// prepareForMetaEmit performs preparatory steps needed prior to
// emitting a meta-data file, notably computing a final hash of
// all meta-data blobs and capturing os args.
func prepareForMetaEmit() ([]rtcov.CovMetaBlob, error) {
// Ask the runtime for the list of coverage meta-data symbols.
ml := getCovMetaList()
// In the normal case (go build -o prog.exe ... ; ./prog.exe)
// len(ml) will always be non-zero, but we check here since at
// some point this function will be reachable via user-callable
// APIs (for example, to write out coverage data from a server
// program that doesn't ever call os.Exit).
if len(ml) == 0 {
return nil, nil
}
s := &emitState{
metalist: ml,
debug: os.Getenv("GOCOVERDEBUG") != "",
}
// Capture os.Args() now so as to avoid issues if args
// are rewritten during program execution.
capturedOsArgs = captureOsArgs()
if s.debug {
fmt.Fprintf(os.Stderr, "=+= GOCOVERDIR is %s\n", os.Getenv("GOCOVERDIR"))
fmt.Fprintf(os.Stderr, "=+= contents of covmetalist:\n")
for k, b := range ml {
fmt.Fprintf(os.Stderr, "=+= slot: %d path: %s ", k, b.PkgPath)
if b.PkgID != -1 {
fmt.Fprintf(os.Stderr, " hcid: %d", b.PkgID)
}
fmt.Fprintf(os.Stderr, "\n")
}
pm := getCovPkgMap()
fmt.Fprintf(os.Stderr, "=+= remap table:\n")
for from, to := range pm {
fmt.Fprintf(os.Stderr, "=+= from %d to %d\n",
uint32(from), uint32(to))
}
}
h := md5.New()
tlen := uint64(unsafe.Sizeof(coverage.MetaFileHeader{}))
for _, entry := range ml {
if _, err := h.Write(entry.Hash[:]); err != nil {
return nil, err
}
tlen += uint64(entry.Len)
ecm := coverage.CounterMode(entry.CounterMode)
if modeClash(ecm) {
return nil, fmt.Errorf("coverage counter mode clash: package %s uses mode=%d, but package %s uses mode=%s\n", ml[0].PkgPath, cmode, entry.PkgPath, ecm)
}
ecg := coverage.CounterGranularity(entry.CounterGranularity)
if granClash(ecg) {
return nil, fmt.Errorf("coverage counter granularity clash: package %s uses gran=%d, but package %s uses gran=%s\n", ml[0].PkgPath, cgran, entry.PkgPath, ecg)
}
}
// Hash mode and granularity as well.
h.Write([]byte(cmode.String()))
h.Write([]byte(cgran.String()))
// Compute final digest.
fh := h.Sum(nil)
copy(finalHash[:], fh)
finalHashComputed = true
finalMetaLen = tlen
return ml, nil
}
// emitMetaDataToDirectory emits the meta-data output file to the specified
// directory, returning an error if something went wrong.
func emitMetaDataToDirectory(outdir string, ml []rtcov.CovMetaBlob) error {
ml, err := prepareForMetaEmit()
if err != nil {
return err
}
if len(ml) == 0 {
return nil
}
metaDataEmitAttempted = true
s := &emitState{
metalist: ml,
debug: os.Getenv("GOCOVERDEBUG") != "",
outdir: outdir,
}
// Open output files.
if err := s.openOutputFiles(finalHash, finalMetaLen, metaDataFile); err != nil {
return err
}
// Emit meta-data file only if needed (may already be present).
if s.needMetaDataFile() {
if err := s.emitMetaDataFile(finalHash, finalMetaLen); err != nil {
return err
}
}
return nil
}
// emitCounterData emits the counter data output file for this coverage run.
// This entry point is intended to be invoked by the runtime when an
// instrumented program is terminating or calling os.Exit().
func emitCounterData() {
if goCoverDir == "" || !finalHashComputed || covProfileAlreadyEmitted {
return
}
if err := emitCounterDataToDirectory(goCoverDir); err != nil {
fmt.Fprintf(os.Stderr, "error: coverage counter data emit failed: %v\n", err)
if os.Getenv("GOCOVERDEBUG") != "" {
panic("counter-data write failure")
}
}
}
// emitCounterDataToDirectory emits the counter-data output file for this coverage run.
func emitCounterDataToDirectory(outdir string) error {
// Ask the runtime for the list of coverage counter symbols.
cl := getCovCounterList()
if len(cl) == 0 {
// no work to do here.
return nil
}
if !finalHashComputed {
return fmt.Errorf("error: meta-data not available (binary not built with -cover?)")
}
// Ask the runtime for the list of coverage counter symbols.
pm := getCovPkgMap()
s := &emitState{
counterlist: cl,
pkgmap: pm,
outdir: outdir,
debug: os.Getenv("GOCOVERDEBUG") != "",
}
// Open output file.
if err := s.openOutputFiles(finalHash, finalMetaLen, counterDataFile); err != nil {
return err
}
if s.cf == nil {
return fmt.Errorf("counter data output file open failed (no additional info")
}
// Emit counter data file.
if err := s.emitCounterDataFile(finalHash, s.cf); err != nil {
return err
}
if err := s.cf.Close(); err != nil {
return fmt.Errorf("closing counter data file: %v", err)
}
// Counter file has now been closed. Rename the temp to the
// final desired path.
if err := os.Rename(s.cftmp, s.cfname); err != nil {
return fmt.Errorf("writing %s: rename from %s failed: %v\n", s.cfname, s.cftmp, err)
}
return nil
}
// emitCounterDataToWriter emits counter data for this coverage run to an io.Writer.
func (s *emitState) emitCounterDataToWriter(w io.Writer) error {
if err := s.emitCounterDataFile(finalHash, w); err != nil {
return err
}
return nil
}
// openMetaFile determines whether we need to emit a meta-data output
// file, or whether we can reuse the existing file in the coverage out
// dir. It updates mfname/mftmp/mf fields in 's', returning an error
// if something went wrong. See the comment on the emitState type
// definition above for more on how file opening is managed.
func (s *emitState) openMetaFile(metaHash [16]byte, metaLen uint64) error {
// Open meta-outfile for reading to see if it exists.
fn := fmt.Sprintf("%s.%x", coverage.MetaFilePref, metaHash)
s.mfname = filepath.Join(s.outdir, fn)
fi, err := os.Stat(s.mfname)
if err != nil || fi.Size() != int64(metaLen) {
// We need a new meta-file.
tname := "tmp." + fn + strconv.FormatInt(time.Now().UnixNano(), 10)
s.mftmp = filepath.Join(s.outdir, tname)
s.mf, err = os.Create(s.mftmp)
if err != nil {
return fmt.Errorf("creating meta-data file %s: %v", s.mftmp, err)
}
}
return nil
}
// openCounterFile opens an output file for the counter data portion
// of a test coverage run. If updates the 'cfname' and 'cf' fields in
// 's', returning an error if something went wrong.
func (s *emitState) openCounterFile(metaHash [16]byte) error {
processID := os.Getpid()
fn := fmt.Sprintf(coverage.CounterFileTempl, coverage.CounterFilePref, metaHash, processID, time.Now().UnixNano())
s.cfname = filepath.Join(s.outdir, fn)
s.cftmp = filepath.Join(s.outdir, "tmp."+fn)
var err error
s.cf, err = os.Create(s.cftmp)
if err != nil {
return fmt.Errorf("creating counter data file %s: %v", s.cftmp, err)
}
return nil
}
// openOutputFiles opens output files in preparation for emitting
// coverage data. In the case of the meta-data file, openOutputFiles
// may determine that we can reuse an existing meta-data file in the
// outdir, in which case it will leave the 'mf' field in the state
// struct as nil. If a new meta-file is needed, the field 'mfname'
// will be the final desired path of the meta file, 'mftmp' will be a
// temporary file, and 'mf' will be an open os.File pointer for
// 'mftmp'. The idea is that the client/caller will write content into
// 'mf', close it, and then rename 'mftmp' to 'mfname'. This function
// also opens the counter data output file, setting 'cf' and 'cfname'
// in the state struct.
func (s *emitState) openOutputFiles(metaHash [16]byte, metaLen uint64, which fileType) error {
fi, err := os.Stat(s.outdir)
if err != nil {
return fmt.Errorf("output directory %q inaccessible (err: %v); no coverage data written", s.outdir, err)
}
if !fi.IsDir() {
return fmt.Errorf("output directory %q not a directory; no coverage data written", s.outdir)
}
if (which & metaDataFile) != 0 {
if err := s.openMetaFile(metaHash, metaLen); err != nil {
return err
}
}
if (which & counterDataFile) != 0 {
if err := s.openCounterFile(metaHash); err != nil {
return err
}
}
return nil
}
// emitMetaDataFile emits coverage meta-data to a previously opened
// temporary file (s.mftmp), then renames the generated file to the
// final path (s.mfname).
func (s *emitState) emitMetaDataFile(finalHash [16]byte, tlen uint64) error {
if err := writeMetaData(s.mf, s.metalist, cmode, cgran, finalHash); err != nil {
return fmt.Errorf("writing %s: %v\n", s.mftmp, err)
}
if err := s.mf.Close(); err != nil {
return fmt.Errorf("closing meta data temp file: %v", err)
}
// Temp file has now been flushed and closed. Rename the temp to the
// final desired path.
if err := os.Rename(s.mftmp, s.mfname); err != nil {
return fmt.Errorf("writing %s: rename from %s failed: %v\n", s.mfname, s.mftmp, err)
}
return nil
}
// needMetaDataFile returns TRUE if we need to emit a meta-data file
// for this program run. It should be used only after
// openOutputFiles() has been invoked.
func (s *emitState) needMetaDataFile() bool {
return s.mf != nil
}
func writeMetaData(w io.Writer, metalist []rtcov.CovMetaBlob, cmode coverage.CounterMode, gran coverage.CounterGranularity, finalHash [16]byte) error {
mfw := encodemeta.NewCoverageMetaFileWriter("<io.Writer>", w)
// Note: "sd" is re-initialized on each iteration of the loop
// below, and would normally be declared inside the loop, but
// placed here escape analysis since we capture it in bufHdr.
var sd []byte
bufHdr := (*reflect.SliceHeader)(unsafe.Pointer(&sd))
var blobs [][]byte
for _, e := range metalist {
bufHdr.Data = uintptr(unsafe.Pointer(e.P))
bufHdr.Len = int(e.Len)
bufHdr.Cap = int(e.Len)
blobs = append(blobs, sd)
}
return mfw.Write(finalHash, blobs, cmode, gran)
}
func (s *emitState) VisitFuncs(f encodecounter.CounterVisitorFn) error {
var sd []atomic.Uint32
var tcounters []uint32
bufHdr := (*reflect.SliceHeader)(unsafe.Pointer(&sd))
rdCounters := func(actrs []atomic.Uint32, ctrs []uint32) []uint32 {
ctrs = ctrs[:0]
for i := range actrs {
ctrs = append(ctrs, actrs[i].Load())
}
return ctrs
}
dpkg := uint32(0)
for _, c := range s.counterlist {
bufHdr.Data = uintptr(unsafe.Pointer(c.Counters))
bufHdr.Len = int(c.Len)
bufHdr.Cap = int(c.Len)
for i := 0; i < len(sd); i++ {
// Skip ahead until the next non-zero value.
sdi := sd[i].Load()
if sdi == 0 {
continue
}
// We found a function that was executed.
nCtrs := sd[i+coverage.NumCtrsOffset].Load()
pkgId := sd[i+coverage.PkgIdOffset].Load()
funcId := sd[i+coverage.FuncIdOffset].Load()
cst := i + coverage.FirstCtrOffset
counters := sd[cst : cst+int(nCtrs)]
// Check to make sure that we have at least one live
// counter. See the implementation note in ClearCoverageCounters
// for a description of why this is needed.
isLive := false
for i := 0; i < len(counters); i++ {
if counters[i].Load() != 0 {
isLive = true
break
}
}
if !isLive {
// Skip this function.
i += coverage.FirstCtrOffset + int(nCtrs) - 1
continue
}
if s.debug {
if pkgId != dpkg {
dpkg = pkgId
fmt.Fprintf(os.Stderr, "\n=+= %d: pk=%d visit live fcn",
i, pkgId)
}
fmt.Fprintf(os.Stderr, " {i=%d F%d NC%d}", i, funcId, nCtrs)
}
// Vet and/or fix up package ID. A package ID of zero
// indicates that there is some new package X that is a
// runtime dependency, and this package has code that
// executes before its corresponding init package runs.
// This is a fatal error that we should only see during
// Go development (e.g. tip).
ipk := int32(pkgId)
if ipk == 0 {
fmt.Fprintf(os.Stderr, "\n")
reportErrorInHardcodedList(int32(i), ipk, funcId, nCtrs)
} else if ipk < 0 {
if newId, ok := s.pkgmap[int(ipk)]; ok {
pkgId = uint32(newId)
} else {
fmt.Fprintf(os.Stderr, "\n")
reportErrorInHardcodedList(int32(i), ipk, funcId, nCtrs)
}
} else {
// The package ID value stored in the counter array
// has 1 added to it (so as to preclude the
// possibility of a zero value ; see
// runtime.addCovMeta), so subtract off 1 here to form
// the real package ID.
pkgId--
}
tcounters = rdCounters(counters, tcounters)
if err := f(pkgId, funcId, tcounters); err != nil {
return err
}
// Skip over this function.
i += coverage.FirstCtrOffset + int(nCtrs) - 1
}
if s.debug {
fmt.Fprintf(os.Stderr, "\n")
}
}
return nil
}
// captureOsArgs converts os.Args() into the format we use to store
// this info in the counter data file (counter data file "args"
// section is a generic key-value collection). See the 'args' section
// in internal/coverage/defs.go for more info. The args map
// is also used to capture GOOS + GOARCH values as well.
func captureOsArgs() map[string]string {
m := make(map[string]string)
m["argc"] = strconv.Itoa(len(os.Args))
for k, a := range os.Args {
m[fmt.Sprintf("argv%d", k)] = a
}
m["GOOS"] = runtime.GOOS
m["GOARCH"] = runtime.GOARCH
return m
}
// emitCounterDataFile emits the counter data portion of a
// coverage output file (to the file 's.cf').
func (s *emitState) emitCounterDataFile(finalHash [16]byte, w io.Writer) error {
cfw := encodecounter.NewCoverageDataWriter(w, coverage.CtrULeb128)
if err := cfw.Write(finalHash, capturedOsArgs, s); err != nil {
return err
}
return nil
}
// markProfileEmitted signals the runtime/coverage machinery that
// coverate data output files have already been written out, and there
// is no need to take any additional action at exit time. This
// function is called (via linknamed reference) from the
// coverage-related boilerplate code in _testmain.go emitted for go
// unit tests.
func markProfileEmitted(val bool) {
covProfileAlreadyEmitted = val
}
func reportErrorInHardcodedList(slot, pkgID int32, fnID, nCtrs uint32) {
metaList := getCovMetaList()
pkgMap := getCovPkgMap()
println("internal error in coverage meta-data tracking:")
println("encountered bad pkgID:", pkgID, " at slot:", slot,
" fnID:", fnID, " numCtrs:", nCtrs)
println("list of hard-coded runtime package IDs needs revising.")
println("[see the comment on the 'rtPkgs' var in ")
println(" <goroot>/src/internal/coverage/pkid.go]")
println("registered list:")
for k, b := range metaList {
print("slot: ", k, " path='", b.PkgPath, "' ")
if b.PkgID != -1 {
print(" hard-coded id: ", b.PkgID)
}
println("")
}
println("remap table:")
for from, to := range pkgMap {
println("from ", from, " to ", to)
}
}