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git.go
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git.go
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// Copyright 2017 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 vcs
import (
"bufio"
"bytes"
"errors"
"fmt"
"net/mail"
"os"
"os/exec"
"regexp"
"sort"
"strings"
"time"
"github.com/google/syzkaller/pkg/debugtracer"
"github.com/google/syzkaller/pkg/hash"
"github.com/google/syzkaller/pkg/log"
"github.com/google/syzkaller/pkg/osutil"
)
type git struct {
dir string
ignoreCC map[string]bool
precious bool
sandbox bool
}
func newGit(dir string, ignoreCC map[string]bool, opts []RepoOpt) *git {
git := &git{
dir: dir,
ignoreCC: ignoreCC,
sandbox: true,
}
for _, opt := range opts {
switch opt {
case OptPrecious:
git.precious = true
case OptDontSandbox:
git.sandbox = false
}
}
return git
}
func filterEnv() []string {
// We have to filter various git environment variables - if
// these variables are set (e.g. if a test is being run as
// part of a rebase) we're going to be acting on some other
// repository (e.g the syzkaller tree itself) rather than the
// intended repo.
env := os.Environ()
for i := 0; i < len(env); i++ {
if strings.HasPrefix(env[i], "GIT_DIR") ||
strings.HasPrefix(env[i], "GIT_WORK_TREE") ||
strings.HasPrefix(env[i], "GIT_INDEX_FILE") ||
strings.HasPrefix(env[i], "GIT_OBJECT_DIRECTORY") {
env = append(env[:i], env[i+1:]...)
i--
}
}
return env
}
func (git *git) Poll(repo, branch string) (*Commit, error) {
git.reset()
origin, err := git.git("remote", "get-url", "origin")
if err != nil || strings.TrimSpace(string(origin)) != repo {
// The repo is here, but it has wrong origin (e.g. repo in config has changed), re-clone.
if err := git.clone(repo, branch); err != nil {
return nil, err
}
}
// Use origin/branch for the case the branch was force-pushed,
// in such case branch is not the same is origin/branch and we will
// stuck with the local version forever (git checkout won't fail).
if _, err := git.git("checkout", "origin/"+branch); err != nil {
// No such branch (e.g. branch in config has changed), re-clone.
if err := git.clone(repo, branch); err != nil {
return nil, err
}
}
if _, err := git.git("fetch", "--force"); err != nil {
// Something else is wrong, re-clone.
if err := git.clone(repo, branch); err != nil {
return nil, err
}
}
if _, err := git.git("checkout", "origin/"+branch); err != nil {
return nil, err
}
if _, err := git.git("submodule", "update", "--init"); err != nil {
return nil, err
}
return git.HeadCommit()
}
func (git *git) CheckoutBranch(repo, branch string) (*Commit, error) {
if err := git.repair(); err != nil {
return nil, err
}
repoHash := hash.String([]byte(repo))
// Because the HEAD is detached, submodules assumes "origin" to be the default
// remote when initializing.
// This sets "origin" to be the current remote.
// Ignore errors as we can double add or remove the same remote and that will fail.
git.git("remote", "rm", "origin")
git.git("remote", "add", "origin", repo)
git.git("remote", "add", repoHash, repo)
_, err := git.git("fetch", "--force", repoHash, branch)
if err != nil {
return nil, err
}
if _, err := git.git("checkout", "FETCH_HEAD", "--force"); err != nil {
return nil, err
}
if _, err := git.git("submodule", "update", "--init"); err != nil {
return nil, err
}
// If the branch checkout had to be "forced" the directory may
// contain remaining untracked files.
// Clean again to ensure the new branch is in a clean state.
if err := git.repair(); err != nil {
return nil, err
}
return git.HeadCommit()
}
func (git *git) CheckoutCommit(repo, commit string) (*Commit, error) {
if err := git.repair(); err != nil {
return nil, err
}
if err := git.fetchRemote(repo, commit); err != nil {
return nil, err
}
return git.SwitchCommit(commit)
}
func (git *git) fetchRemote(repo, commit string) error {
repoHash := hash.String([]byte(repo))
// Ignore error as we can double add the same remote and that will fail.
git.git("remote", "add", repoHash, repo)
fetchArgs := []string{"fetch", "--force", "--tags", repoHash}
if commit != "" && gitFullHashRe.MatchString(commit) {
// This trick only works with full commit hashes.
fetchArgs = append(fetchArgs, commit)
}
_, err := git.git(fetchArgs...)
if err != nil {
var verbose *osutil.VerboseError
if errors.As(err, &verbose) &&
bytes.Contains(verbose.Output, []byte("error: cannot lock ref")) {
// It can happen that the fetched repo has tags names that conflict
// with the ones already present in the repository.
// Try to fetch more, but this time prune tags, it should help.
// The --prune-tags option will remove all tags that are not present
// in this remote repo, so don't do it always. Only when necessary.
_, err = git.git("fetch", "--force", "--tags", "--prune", "--prune-tags", repoHash)
}
}
return err
}
func (git *git) SwitchCommit(commit string) (*Commit, error) {
if !git.precious {
git.git("reset", "--hard")
git.git("clean", "-fdx")
}
if _, err := git.git("checkout", commit); err != nil {
return nil, err
}
if _, err := git.git("submodule", "update", "--init"); err != nil {
return nil, err
}
return git.HeadCommit()
}
func (git *git) clone(repo, branch string) error {
if git.precious {
return fmt.Errorf("won't reinit precious repo")
}
if err := git.initRepo(nil); err != nil {
return err
}
if _, err := git.git("remote", "add", "origin", repo); err != nil {
return err
}
if _, err := git.git("fetch", "origin", branch); err != nil {
return err
}
return nil
}
func (git *git) reset() error {
// This function tries to reset git repo state to a known clean state.
if git.precious {
return nil
}
git.git("reset", "--hard", "--recurse-submodules")
git.git("clean", "-xfdf")
git.git("submodule", "foreach", "--recursive", "git", "clean", "-xfdf")
git.git("bisect", "reset")
_, err := git.git("reset", "--hard", "--recurse-submodules")
return err
}
func (git *git) repair() error {
if err := git.reset(); err != nil {
return git.initRepo(err)
}
return nil
}
func (git *git) initRepo(reason error) error {
if reason != nil {
log.Logf(1, "git: initializing repo at %v: %v", git.dir, reason)
}
if err := os.RemoveAll(git.dir); err != nil {
return fmt.Errorf("failed to remove repo dir: %w", err)
}
if err := osutil.MkdirAll(git.dir); err != nil {
return fmt.Errorf("failed to create repo dir: %w", err)
}
if git.sandbox {
if err := osutil.SandboxChown(git.dir); err != nil {
return err
}
}
if _, err := git.git("init"); err != nil {
return err
}
return nil
}
func (git *git) Contains(commit string) (bool, error) {
_, err := git.git("merge-base", "--is-ancestor", commit, "HEAD")
return err == nil, nil
}
func (git *git) HeadCommit() (*Commit, error) {
return git.getCommit("HEAD")
}
func (git *git) getCommit(commit string) (*Commit, error) {
output, err := git.git("log", "--format=%H%n%s%n%ae%n%an%n%ad%n%P%n%cd%n%b", "-n", "1", commit)
if err != nil {
return nil, err
}
return gitParseCommit(output, nil, nil, git.ignoreCC)
}
func gitParseCommit(output, user, domain []byte, ignoreCC map[string]bool) (*Commit, error) {
lines := bytes.Split(output, []byte{'\n'})
if len(lines) < 8 || len(lines[0]) != 40 {
return nil, fmt.Errorf("unexpected git log output: %q", output)
}
const dateFormat = "Mon Jan 2 15:04:05 2006 -0700"
date, err := time.Parse(dateFormat, string(lines[4]))
if err != nil {
return nil, fmt.Errorf("failed to parse date in git log output: %w\n%q", err, output)
}
commitDate, err := time.Parse(dateFormat, string(lines[6]))
if err != nil {
return nil, fmt.Errorf("failed to parse date in git log output: %w\n%q", err, output)
}
recipients := make(map[string]bool)
recipients[strings.ToLower(string(lines[2]))] = true
var tags []string
// Use summary line + all description lines.
for _, line := range append([][]byte{lines[1]}, lines[7:]...) {
if user != nil {
userPos := bytes.Index(line, user)
if userPos != -1 {
domainPos := bytes.Index(line[userPos+len(user)+1:], domain)
if domainPos != -1 {
startPos := userPos + len(user)
endPos := userPos + len(user) + domainPos + 1
tag := string(line[startPos:endPos])
present := false
for _, tag1 := range tags {
if tag1 == tag {
present = true
break
}
}
if !present {
tags = append(tags, tag)
}
}
}
}
for _, re := range ccRes {
matches := re.FindSubmatchIndex(line)
if matches == nil {
continue
}
addr, err := mail.ParseAddress(string(line[matches[2]:matches[3]]))
if err != nil {
break
}
email := strings.ToLower(addr.Address)
if ignoreCC[email] {
continue
}
recipients[email] = true
break
}
}
sortedRecipients := make(Recipients, 0, len(recipients))
for addr := range recipients {
sortedRecipients = append(sortedRecipients, RecipientInfo{mail.Address{Address: addr}, To})
}
sort.Sort(sortedRecipients)
parents := strings.Split(string(lines[5]), " ")
com := &Commit{
Hash: string(lines[0]),
Title: string(lines[1]),
Author: string(lines[2]),
AuthorName: string(lines[3]),
Parents: parents,
Recipients: sortedRecipients,
Tags: tags,
Date: date,
CommitDate: commitDate,
}
return com, nil
}
func (git *git) GetCommitByTitle(title string) (*Commit, error) {
commits, _, err := git.GetCommitsByTitles([]string{title})
if err != nil || len(commits) == 0 {
return nil, err
}
return commits[0], nil
}
const (
fetchCommitsMaxAgeInYears = 5
)
func (git *git) GetCommitsByTitles(titles []string) ([]*Commit, []string, error) {
var greps []string
m := make(map[string]string)
for _, title := range titles {
canonical := CanonicalizeCommit(title)
greps = append(greps, canonical)
m[canonical] = title
}
since := time.Now().Add(-time.Hour * 24 * 365 * fetchCommitsMaxAgeInYears).Format("01-02-2006")
commits, err := git.fetchCommits(since, "HEAD", "", "", greps, true)
if err != nil {
return nil, nil, err
}
var results []*Commit
for _, com := range commits {
canonical := CanonicalizeCommit(com.Title)
if orig := m[canonical]; orig != "" {
delete(m, canonical)
results = append(results, com)
com.Title = orig
}
}
var missing []string
for _, orig := range m {
missing = append(missing, orig)
}
return results, missing, nil
}
func (git *git) ListCommitHashes(baseCommit string) ([]string, error) {
output, err := git.git("log", "--pretty=format:%h", baseCommit)
if err != nil {
return nil, err
}
return strings.Split(string(output), "\n"), nil
}
func (git *git) ExtractFixTagsFromCommits(baseCommit, email string) ([]*Commit, error) {
user, domain, err := splitEmail(email)
if err != nil {
return nil, fmt.Errorf("failed to parse email %q: %w", email, err)
}
grep := user + "+.*" + domain
since := time.Now().Add(-time.Hour * 24 * 365 * fetchCommitsMaxAgeInYears).Format("01-02-2006")
return git.fetchCommits(since, baseCommit, user, domain, []string{grep}, false)
}
func (git *git) fetchCommits(since, base, user, domain string, greps []string, fixedStrings bool) ([]*Commit, error) {
const commitSeparator = "---===syzkaller-commit-separator===---"
args := []string{"log", "--since", since, "--format=%H%n%s%n%ae%n%an%n%ad%n%P%n%cd%n%b%n" + commitSeparator}
if fixedStrings {
args = append(args, "--fixed-strings")
}
for _, grep := range greps {
args = append(args, "--grep", grep)
}
args = append(args, base)
cmd := exec.Command("git", args...)
cmd.Dir = git.dir
cmd.Env = filterEnv()
if git.sandbox {
if err := osutil.Sandbox(cmd, true, false); err != nil {
return nil, err
}
}
stdout, err := cmd.StdoutPipe()
if err != nil {
return nil, err
}
if err := cmd.Start(); err != nil {
return nil, err
}
defer cmd.Wait()
defer cmd.Process.Kill()
var (
s = bufio.NewScanner(stdout)
buf = new(bytes.Buffer)
separator = []byte(commitSeparator)
commits []*Commit
userBytes []byte
domainBytes []byte
)
if user != "" {
userBytes = []byte(user + "+")
domainBytes = []byte(domain)
}
for s.Scan() {
ln := s.Bytes()
if !bytes.Equal(ln, separator) {
buf.Write(ln)
buf.WriteByte('\n')
continue
}
com, err := gitParseCommit(buf.Bytes(), userBytes, domainBytes, git.ignoreCC)
if err != nil {
return nil, err
}
if user == "" || len(com.Tags) != 0 {
commits = append(commits, com)
}
buf.Reset()
}
return commits, s.Err()
}
func (git *git) git(args ...string) ([]byte, error) {
cmd := osutil.Command("git", args...)
cmd.Dir = git.dir
cmd.Env = filterEnv()
if git.sandbox {
if err := osutil.Sandbox(cmd, true, false); err != nil {
return nil, err
}
}
return osutil.Run(3*time.Hour, cmd)
}
func splitEmail(email string) (user, domain string, err error) {
addr, err := mail.ParseAddress(email)
if err != nil {
return "", "", err
}
at := strings.IndexByte(addr.Address, '@')
if at == -1 {
return "", "", fmt.Errorf("no @ in email address")
}
user = addr.Address[:at]
domain = addr.Address[at:]
if plus := strings.IndexByte(user, '+'); plus != -1 {
user = user[:plus]
}
return
}
func (git *git) Bisect(bad, good string, dt debugtracer.DebugTracer, pred func() (BisectResult,
error)) ([]*Commit, error) {
git.reset()
firstBad, err := git.getCommit(bad)
if err != nil {
return nil, err
}
output, err := git.git("bisect", "start", bad, good)
if err != nil {
return nil, err
}
defer git.reset()
dt.Log("# git bisect start %v %v\n%s", bad, good, output)
current, err := git.HeadCommit()
if err != nil {
return nil, err
}
var bisectTerms = [...]string{
BisectBad: "bad",
BisectGood: "good",
BisectSkip: "skip",
}
for {
res, err := pred()
// Linux EnvForCommit may cherry-pick some fixes, reset these before the next step.
git.git("reset", "--hard")
if err != nil {
return nil, err
}
if res == BisectBad {
firstBad = current
}
output, err = git.git("bisect", bisectTerms[res])
dt.Log("# git bisect %v %v\n%s", bisectTerms[res], current.Hash, output)
if err != nil {
if bytes.Contains(output, []byte("There are only 'skip'ped commits left to test")) {
return git.bisectInconclusive(output)
}
return nil, err
}
next, err := git.HeadCommit()
if err != nil {
return nil, err
}
if current.Hash == next.Hash {
return []*Commit{firstBad}, nil
}
current = next
}
}
var gitFullHashRe = regexp.MustCompile("[a-f0-9]{40}")
func (git *git) bisectInconclusive(output []byte) ([]*Commit, error) {
// For inconclusive bisection git prints the following message:
//
// There are only 'skip'ped commits left to test.
// The first bad commit could be any of:
// 1f43f400a2cbb02f3d34de8fe30075c070254816
// 4d96e13ee9cd1f7f801e8c7f4b12f09d1da4a5d8
// 5cd856a5ef9aa189df757c322be34ad735a5b17f
// We cannot bisect more!
//
// For conclusive bisection:
//
// 7c3850adbcccc2c6c9e7ab23a7dcbc4926ee5b96 is the first bad commit
var commits []*Commit
for _, hash := range gitFullHashRe.FindAll(output, -1) {
com, err := git.getCommit(string(hash))
if err != nil {
return nil, err
}
commits = append(commits, com)
}
return commits, nil
}
func (git *git) ReleaseTag(commit string) (string, error) {
tags, err := git.previousReleaseTags(commit, true, true, true)
if err != nil {
return "", err
}
if len(tags) == 0 {
return "", fmt.Errorf("no release tags found for commit %v", commit)
}
return tags[0], nil
}
func (git *git) previousReleaseTags(commit string, self, onlyTop, includeRC bool) ([]string, error) {
var tags []string
if self {
output, err := git.git("tag", "--list", "--points-at", commit, "--merged", commit, "v*.*")
if err != nil {
return nil, err
}
tags = gitParseReleaseTags(output, includeRC)
if onlyTop && len(tags) != 0 {
return tags, nil
}
}
output, err := git.git("tag", "--no-contains", commit, "--merged", commit, "v*.*")
if err != nil {
return nil, err
}
tags1 := gitParseReleaseTags(output, includeRC)
tags = append(tags, tags1...)
if len(tags) == 0 {
return nil, fmt.Errorf("no release tags found for commit %v", commit)
}
return tags, nil
}
func (git *git) IsRelease(commit string) (bool, error) {
tags1, err := git.previousReleaseTags(commit, true, false, false)
if err != nil {
return false, err
}
tags2, err := git.previousReleaseTags(commit, false, false, false)
if err != nil {
return false, err
}
return len(tags1) != len(tags2), nil
}
func (git *git) Object(name, commit string) ([]byte, error) {
return git.git("show", fmt.Sprintf("%s:%s", commit, name))
}
func (git *git) MergeBases(firstCommit, secondCommit string) ([]*Commit, error) {
output, err := git.git("merge-base", firstCommit, secondCommit)
if err != nil {
return nil, err
}
ret := []*Commit{}
for _, hash := range strings.Fields(string(output)) {
commit, err := git.getCommit(hash)
if err != nil {
return nil, err
}
ret = append(ret, commit)
}
return ret, nil
}