1 files changed, 416 insertions, 0 deletions
diff --git a/modules/git/git.go b/modules/git/git.go
new file mode 100644
index 00000000..70232c86
--- /dev/null
+++ b/modules/git/git.go
@@ -0,0 +1,416 @@
+// Copyright 2015 The Gogs Authors. All rights reserved.
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package git
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"strings"
+	"time"
+
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/hashicorp/go-version"
+)
+
+// RequiredVersion is the minimum Git version required
+const RequiredVersion = "2.0.0"
+
+var (
+	// GitExecutable is the command name of git
+	// Could be updated to an absolute path while initialization
+	GitExecutable = "git"
+
+	// DefaultContext is the default context to run git commands in, must be initialized by git.InitXxx
+	DefaultContext context.Context
+
+	SupportProcReceive     bool // >= 2.29
+	SupportHashSha256      bool // >= 2.42, SHA-256 repositories no longer an ‘experimental curiosity’
+	InvertedGitFlushEnv    bool // 2.43.1
+	SupportCheckAttrOnBare bool // >= 2.40
+
+	gitVersion *version.Version
+)
+
+// loadGitVersion returns current Git version from shell. Internal usage only.
+func loadGitVersion() error {
+	// doesn't need RWMutex because it's executed by Init()
+	if gitVersion != nil {
+		return nil
+	}
+	stdout, _, runErr := NewCommand(DefaultContext, "version").RunStdString(nil)
+	if runErr != nil {
+		return runErr
+	}
+
+	fields := strings.Fields(stdout)
+	if len(fields) < 3 {
+		return fmt.Errorf("invalid git version output: %s", stdout)
+	}
+
+	var versionString string
+
+	// Handle special case on Windows.
+	i := strings.Index(fields[2], "windows")
+	if i >= 1 {
+		versionString = fields[2][:i-1]
+	} else {
+		versionString = fields[2]
+	}
+
+	var err error
+	gitVersion, err = version.NewVersion(versionString)
+	return err
+}
+
+// SetExecutablePath changes the path of git executable and checks the file permission and version.
+func SetExecutablePath(path string) error {
+	// If path is empty, we use the default value of GitExecutable "git" to search for the location of git.
+	if path != "" {
+		GitExecutable = path
+	}
+	absPath, err := exec.LookPath(GitExecutable)
+	if err != nil {
+		return fmt.Errorf("git not found: %w", err)
+	}
+	GitExecutable = absPath
+
+	err = loadGitVersion()
+	if err != nil {
+		return fmt.Errorf("unable to load git version: %w", err)
+	}
+
+	versionRequired, err := version.NewVersion(RequiredVersion)
+	if err != nil {
+		return err
+	}
+
+	if gitVersion.LessThan(versionRequired) {
+		moreHint := "get git: https://git-scm.com/download/"
+		if runtime.GOOS == "linux" {
+			// there are a lot of CentOS/RHEL users using old git, so we add a special hint for them
+			if _, err = os.Stat("/etc/redhat-release"); err == nil {
+				// ius.io is the recommended official(git-scm.com) method to install git
+				moreHint = "get git: https://git-scm.com/download/linux and https://ius.io"
+			}
+		}
+		return fmt.Errorf("installed git version %q is not supported, Gitea requires git version >= %q, %s", gitVersion.Original(), RequiredVersion, moreHint)
+	}
+
+	return nil
+}
+
+// VersionInfo returns git version information
+func VersionInfo() string {
+	if gitVersion == nil {
+		return "(git not found)"
+	}
+	format := "%s"
+	args := []any{gitVersion.Original()}
+	// Since git wire protocol has been released from git v2.18
+	if setting.Git.EnableAutoGitWireProtocol && CheckGitVersionAtLeast("2.18") == nil {
+		format += ", Wire Protocol %s Enabled"
+		args = append(args, "Version 2") // for focus color
+	}
+
+	return fmt.Sprintf(format, args...)
+}
+
+func checkInit() error {
+	if setting.Git.HomePath == "" {
+		return errors.New("unable to init Git's HomeDir, incorrect initialization of the setting and git modules")
+	}
+	if DefaultContext != nil {
+		log.Warn("git module has been initialized already, duplicate init may work but it's better to fix it")
+	}
+	return nil
+}
+
+// HomeDir is the home dir for git to store the global config file used by Gitea internally
+func HomeDir() string {
+	if setting.Git.HomePath == "" {
+		// strict check, make sure the git module is initialized correctly.
+		// attention: when the git module is called in gitea sub-command (serv/hook), the log module might not obviously show messages to users/developers.
+		// for example: if there is gitea git hook code calling git.NewCommand before git.InitXxx, the integration test won't show the real failure reasons.
+		log.Fatal("Unable to init Git's HomeDir, incorrect initialization of the setting and git modules")
+		return ""
+	}
+	return setting.Git.HomePath
+}
+
+// InitSimple initializes git module with a very simple step, no config changes, no global command arguments.
+// This method doesn't change anything to filesystem. At the moment, it is only used by some Gitea sub-commands.
+func InitSimple(ctx context.Context) error {
+	if err := checkInit(); err != nil {
+		return err
+	}
+
+	DefaultContext = ctx
+	globalCommandArgs = nil
+
+	if setting.Git.Timeout.Default > 0 {
+		defaultCommandExecutionTimeout = time.Duration(setting.Git.Timeout.Default) * time.Second
+	}
+
+	return SetExecutablePath(setting.Git.Path)
+}
+
+// InitFull initializes git module with version check and change global variables, sync gitconfig.
+// It should only be called once at the beginning of the program initialization (TestMain/GlobalInitInstalled) as this code makes unsynchronized changes to variables.
+func InitFull(ctx context.Context) (err error) {
+	if err = InitSimple(ctx); err != nil {
+		return err
+	}
+
+	// when git works with gnupg (commit signing), there should be a stable home for gnupg commands
+	if _, ok := os.LookupEnv("GNUPGHOME"); !ok {
+		_ = os.Setenv("GNUPGHOME", filepath.Join(HomeDir(), ".gnupg"))
+	}
+
+	// Since git wire protocol has been released from git v2.18
+	if setting.Git.EnableAutoGitWireProtocol && CheckGitVersionAtLeast("2.18") == nil {
+		globalCommandArgs = append(globalCommandArgs, "-c", "protocol.version=2")
+	}
+
+	// Explicitly disable credential helper, otherwise Git credentials might leak
+	if CheckGitVersionAtLeast("2.9") == nil {
+		globalCommandArgs = append(globalCommandArgs, "-c", "credential.helper=")
+	}
+	SupportProcReceive = CheckGitVersionAtLeast("2.29") == nil
+	SupportHashSha256 = CheckGitVersionAtLeast("2.42") == nil && !isGogit
+	SupportCheckAttrOnBare = CheckGitVersionAtLeast("2.40") == nil
+	if SupportHashSha256 {
+		SupportedObjectFormats = append(SupportedObjectFormats, Sha256ObjectFormat)
+	} else {
+		log.Warn("sha256 hash support is disabled - requires Git >= 2.42. Gogit is currently unsupported")
+	}
+
+	InvertedGitFlushEnv = CheckGitVersionEqual("2.43.1") == nil
+
+	if setting.LFS.StartServer {
+		if CheckGitVersionAtLeast("2.1.2") != nil {
+			return errors.New("LFS server support requires Git >= 2.1.2")
+		}
+		globalCommandArgs = append(globalCommandArgs, "-c", "filter.lfs.required=", "-c", "filter.lfs.smudge=", "-c", "filter.lfs.clean=")
+	}
+
+	return syncGitConfig()
+}
+
+// syncGitConfig only modifies gitconfig, won't change global variables (otherwise there will be data-race problem)
+func syncGitConfig() (err error) {
+	if err = os.MkdirAll(HomeDir(), os.ModePerm); err != nil {
+		return fmt.Errorf("unable to prepare git home directory %s, err: %w", HomeDir(), err)
+	}
+
+	// first, write user's git config options to git config file
+	// user config options could be overwritten by builtin values later, because if a value is builtin, it must have some special purposes
+	for k, v := range setting.GitConfig.Options {
+		if err = configSet(strings.ToLower(k), v); err != nil {
+			return err
+		}
+	}
+
+	// Git requires setting user.name and user.email in order to commit changes - old comment: "if they're not set just add some defaults"
+	// TODO: need to confirm whether users really need to change these values manually. It seems that these values are dummy only and not really used.
+	// If these values are not really used, then they can be set (overwritten) directly without considering about existence.
+	for configKey, defaultValue := range map[string]string{
+		"user.name":  "Gitea",
+		"user.email": "gitea@fake.local",
+	} {
+		if err := configSetNonExist(configKey, defaultValue); err != nil {
+			return err
+		}
+	}
+
+	// Set git some configurations - these must be set to these values for gitea to work correctly
+	if err := configSet("core.quotePath", "false"); err != nil {
+		return err
+	}
+
+	if CheckGitVersionAtLeast("2.10") == nil {
+		if err := configSet("receive.advertisePushOptions", "true"); err != nil {
+			return err
+		}
+	}
+
+	if CheckGitVersionAtLeast("2.18") == nil {
+		if err := configSet("core.commitGraph", "true"); err != nil {
+			return err
+		}
+		if err := configSet("gc.writeCommitGraph", "true"); err != nil {
+			return err
+		}
+		if err := configSet("fetch.writeCommitGraph", "true"); err != nil {
+			return err
+		}
+	}
+
+	if SupportProcReceive {
+		// set support for AGit flow
+		if err := configAddNonExist("receive.procReceiveRefs", "refs/for"); err != nil {
+			return err
+		}
+	} else {
+		if err := configUnsetAll("receive.procReceiveRefs", "refs/for"); err != nil {
+			return err
+		}
+	}
+
+	// Due to CVE-2022-24765, git now denies access to git directories which are not owned by current user
+	// however, some docker users and samba users find it difficult to configure their systems so that Gitea's git repositories are owned by the Gitea user. (Possibly Windows Service users - but ownership in this case should really be set correctly on the filesystem.)
+	// see issue: https://github.com/go-gitea/gitea/issues/19455
+	// Fundamentally the problem lies with the uid-gid-mapping mechanism for filesystems in docker on windows (and to a lesser extent samba).
+	// Docker's configuration mechanism for local filesystems provides no way of setting this mapping and although there is a mechanism for setting this uid through using cifs mounting it is complicated and essentially undocumented
+	// Thus the owner uid/gid for files on these filesystems will be marked as root.
+	// As Gitea now always use its internal git config file, and access to the git repositories is managed through Gitea,
+	// it is now safe to set "safe.directory=*" for internal usage only.
+	// Please note: the wildcard "*" is only supported by Git 2.30.4/2.31.3/2.32.2/2.33.3/2.34.3/2.35.3/2.36 and later
+	// Although only supported by Git 2.30.4/2.31.3/2.32.2/2.33.3/2.34.3/2.35.3/2.36 and later - this setting is tolerated by earlier versions
+	if err := configAddNonExist("safe.directory", "*"); err != nil {
+		return err
+	}
+	if runtime.GOOS == "windows" {
+		if err := configSet("core.longpaths", "true"); err != nil {
+			return err
+		}
+		if setting.Git.DisableCoreProtectNTFS {
+			err = configSet("core.protectNTFS", "false")
+		} else {
+			err = configUnsetAll("core.protectNTFS", "false")
+		}
+		if err != nil {
+			return err
+		}
+	}
+
+	// By default partial clones are disabled, enable them from git v2.22
+	if !setting.Git.DisablePartialClone && CheckGitVersionAtLeast("2.22") == nil {
+		if err = configSet("uploadpack.allowfilter", "true"); err != nil {
+			return err
+		}
+		err = configSet("uploadpack.allowAnySHA1InWant", "true")
+	} else {
+		if err = configUnsetAll("uploadpack.allowfilter", "true"); err != nil {
+			return err
+		}
+		err = configUnsetAll("uploadpack.allowAnySHA1InWant", "true")
+	}
+
+	return err
+}
+
+// CheckGitVersionAtLeast check git version is at least the constraint version
+func CheckGitVersionAtLeast(atLeast string) error {
+	if err := loadGitVersion(); err != nil {
+		return err
+	}
+	atLeastVersion, err := version.NewVersion(atLeast)
+	if err != nil {
+		return err
+	}
+	if gitVersion.Compare(atLeastVersion) < 0 {
+		return fmt.Errorf("installed git binary version %s is not at least %s", gitVersion.Original(), atLeast)
+	}
+	return nil
+}
+
+// CheckGitVersionEqual checks if the git version is equal to the constraint version.
+func CheckGitVersionEqual(equal string) error {
+	if err := loadGitVersion(); err != nil {
+		return err
+	}
+	atLeastVersion, err := version.NewVersion(equal)
+	if err != nil {
+		return err
+	}
+	if !gitVersion.Equal(atLeastVersion) {
+		return fmt.Errorf("installed git binary version %s is not equal to %s", gitVersion.Original(), equal)
+	}
+	return nil
+}
+
+func configSet(key, value string) error {
+	stdout, _, err := NewCommand(DefaultContext, "config", "--global", "--get").AddDynamicArguments(key).RunStdString(nil)
+	if err != nil && !IsErrorExitCode(err, 1) {
+		return fmt.Errorf("failed to get git config %s, err: %w", key, err)
+	}
+
+	currValue := strings.TrimSpace(stdout)
+	if currValue == value {
+		return nil
+	}
+
+	_, _, err = NewCommand(DefaultContext, "config", "--global").AddDynamicArguments(key, value).RunStdString(nil)
+	if err != nil {
+		return fmt.Errorf("failed to set git global config %s, err: %w", key, err)
+	}
+
+	return nil
+}
+
+func configSetNonExist(key, value string) error {
+	_, _, err := NewCommand(DefaultContext, "config", "--global", "--get").AddDynamicArguments(key).RunStdString(nil)
+	if err == nil {
+		// already exist
+		return nil
+	}
+	if IsErrorExitCode(err, 1) {
+		// not exist, set new config
+		_, _, err = NewCommand(DefaultContext, "config", "--global").AddDynamicArguments(key, value).RunStdString(nil)
+		if err != nil {
+			return fmt.Errorf("failed to set git global config %s, err: %w", key, err)
+		}
+		return nil
+	}
+
+	return fmt.Errorf("failed to get git config %s, err: %w", key, err)
+}
+
+func configAddNonExist(key, value string) error {
+	_, _, err := NewCommand(DefaultContext, "config", "--global", "--get").AddDynamicArguments(key, regexp.QuoteMeta(value)).RunStdString(nil)
+	if err == nil {
+		// already exist
+		return nil
+	}
+	if IsErrorExitCode(err, 1) {
+		// not exist, add new config
+		_, _, err = NewCommand(DefaultContext, "config", "--global", "--add").AddDynamicArguments(key, value).RunStdString(nil)
+		if err != nil {
+			return fmt.Errorf("failed to add git global config %s, err: %w", key, err)
+		}
+		return nil
+	}
+	return fmt.Errorf("failed to get git config %s, err: %w", key, err)
+}
+
+func configUnsetAll(key, value string) error {
+	_, _, err := NewCommand(DefaultContext, "config", "--global", "--get").AddDynamicArguments(key).RunStdString(nil)
+	if err == nil {
+		// exist, need to remove
+		_, _, err = NewCommand(DefaultContext, "config", "--global", "--unset-all").AddDynamicArguments(key, regexp.QuoteMeta(value)).RunStdString(nil)
+		if err != nil {
+			return fmt.Errorf("failed to unset git global config %s, err: %w", key, err)
+		}
+		return nil
+	}
+	if IsErrorExitCode(err, 1) {
+		// not exist
+		return nil
+	}
+	return fmt.Errorf("failed to get git config %s, err: %w", key, err)
+}
+
+// Fsck verifies the connectivity and validity of the objects in the database
+func Fsck(ctx context.Context, repoPath string, timeout time.Duration, args TrustedCmdArgs) error {
+	return NewCommand(ctx, "fsck").AddArguments(args...).Run(&RunOpts{Timeout: timeout, Dir: repoPath})
+}