From 2cd785fc9e7d25e7504fa552cd94607d250665b0 Mon Sep 17 00:00:00 2001
From: Runxi Yu <me@runxiyu.org>
Date: Sun, 16 Feb 2025 00:32:46 +0800
Subject: [PATCH] ssh_*: Use pure go-git SSH handling (receive and upload)

---
 misc.go                    | 18 ++++++++++++++++++
 ssh_handle_receive_pack.go | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 ssh_handle_upload_pack.go  | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 ssh_server.go              | 39 ++++++++++++++++-----------------------

diff --git a/misc.go b/misc.go
index a43f20a4254f3ea658de6473a5caa5f374cf0c27..5077b83d608267fea7000192ff1c5b8de7d021b4 100644
--- a/misc.go
+++ b/misc.go
@@ -1,6 +1,24 @@
 package main
 
+import (
+	"errors"
+	"strings"
+)
+
 type name_desc_t struct {
 	Name        string
 	Description string
 }
+
+var err_environ_no_separator = errors.New("No separator found in environ line")
+
+func environ_to_map(environ_strings []string) (result map[string]string, err error) {
+	for _, environ_string := range environ_strings {
+		key, value, found := strings.Cut(environ_string, "=")
+		if !found {
+			return result, err_environ_no_separator
+		}
+		result[key] = value
+	}
+	return result, err_environ_no_separator
+}
diff --git a/ssh_handle_receive_pack.go b/ssh_handle_receive_pack.go
new file mode 100644
index 0000000000000000000000000000000000000000..69af8f5bb0589364c3449ba8aa39a545384fe0c3
--- /dev/null
+++ b/ssh_handle_receive_pack.go
@@ -0,0 +1,49 @@
+package main
+
+import (
+	glider_ssh "github.com/gliderlabs/ssh"
+	"github.com/go-git/go-billy/v5/osfs"
+	"github.com/go-git/go-git/v5/plumbing/protocol/packp"
+	"github.com/go-git/go-git/v5/plumbing/transport"
+	transport_server "github.com/go-git/go-git/v5/plumbing/transport/server"
+)
+
+func ssh_handle_receive_pack(session glider_ssh.Session, repo_identifier string) (err error) {
+	repo_path, err := get_repo_path_from_ssh_path(session.Context(), repo_identifier)
+	if err != nil {
+		return err
+	}
+	endpoint, err := transport.NewEndpoint("/")
+	if err != nil {
+		return err
+	}
+	billy_fs := osfs.New(repo_path)
+	fs_loader := transport_server.NewFilesystemLoader(billy_fs)
+	transport := transport_server.NewServer(fs_loader)
+	receive_pack_session, err := transport.NewReceivePackSession(endpoint, nil)
+	if err != nil {
+		return err
+	}
+	advertised_references, err := receive_pack_session.AdvertisedReferencesContext(session.Context())
+	if err != nil {
+		return err
+	}
+	err = advertised_references.Encode(session)
+	if err != nil {
+		return err
+	}
+	reference_update_request := packp.NewReferenceUpdateRequest()
+	err = reference_update_request.Decode(session)
+	if err != nil {
+		return err
+	}
+	report_status, err := receive_pack_session.ReceivePack(session.Context(), reference_update_request)
+	if err != nil {
+		return err
+	}
+	err = report_status.Encode(session)
+	if err != nil {
+		return err
+	}
+	return nil
+}
diff --git a/ssh_handle_upload_pack.go b/ssh_handle_upload_pack.go
new file mode 100644
index 0000000000000000000000000000000000000000..8f7d9c9278dd526e342cfe65b0194b694b5d1c5e
--- /dev/null
+++ b/ssh_handle_upload_pack.go
@@ -0,0 +1,49 @@
+package main
+
+import (
+	glider_ssh "github.com/gliderlabs/ssh"
+	"github.com/go-git/go-billy/v5/osfs"
+	"github.com/go-git/go-git/v5/plumbing/protocol/packp"
+	"github.com/go-git/go-git/v5/plumbing/transport"
+	"github.com/go-git/go-git/v5/plumbing/transport/server"
+)
+
+func ssh_handle_upload_pack(session glider_ssh.Session, repo_identifier string) (err error) {
+	repo_path, err := get_repo_path_from_ssh_path(session.Context(), repo_identifier)
+	if err != nil {
+		return err
+	}
+	endpoint, err := transport.NewEndpoint("/")
+	if err != nil {
+		return err
+	}
+	billy_fs := osfs.New(repo_path)
+	fs_loader := server.NewFilesystemLoader(billy_fs)
+	transport := server.NewServer(fs_loader)
+	upload_pack_session, err := transport.NewUploadPackSession(endpoint, nil)
+	if err != nil {
+		return err
+	}
+	advertised_references, err := upload_pack_session.AdvertisedReferencesContext(session.Context())
+	if err != nil {
+		return err
+	}
+	err = advertised_references.Encode(session)
+	if err != nil {
+		return err
+	}
+	reference_update_request := packp.NewUploadPackRequest()
+	err = reference_update_request.Decode(session)
+	if err != nil {
+		return err
+	}
+	report_status, err := upload_pack_session.UploadPack(session.Context(), reference_update_request)
+	if err != nil {
+		return err
+	}
+	err = report_status.Encode(session)
+	if err != nil {
+		return err
+	}
+	return nil
+}
diff --git a/ssh_server.go b/ssh_server.go
index 0dde4b4bb27d95d318d1d295f273dfe1bb8ba132..b3a6a52a233096001ae4da8bb402710c43608920 100644
--- a/ssh_server.go
+++ b/ssh_server.go
@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"net"
 	"os"
-	"os/exec"
 	"strings"
 
 	glider_ssh "github.com/gliderlabs/ssh"
@@ -51,32 +50,26 @@ 				fmt.Fprintln(session.Stderr(), "Insufficient arguments\r")
 				return
 			}
 
-			if cmd[0] != "git-upload-pack" {
-				fmt.Fprintln(session.Stderr(), "Unsupported command\r")
-				return
-			}
-
-			fs_path, err := get_repo_path_from_ssh_path(session.Context(), cmd[1])
-			if err != nil {
-				fmt.Fprintln(session.Stderr(), "Error while getting repo path:", err, "\r")
+			switch cmd[0] {
+			case "git-upload-pack":
+				if len(cmd) > 2 {
+					fmt.Fprintln(session.Stderr(), "Too many arguments\r")
+					return
+				}
+				err = ssh_handle_upload_pack(session, cmd[1])
+			case "git-receive-pack":
+				if len(cmd) > 2 {
+					fmt.Fprintln(session.Stderr(), "Too many arguments\r")
+					return
+				}
+				err = ssh_handle_receive_pack(session, cmd[1])
+			default:
+				fmt.Fprintln(session.Stderr(), "Unsupported command: "+cmd[0]+"\r")
 				return
 			}
-
-			proc := exec.CommandContext(session.Context(), cmd[0], fs_path)
-			proc.Stdin = session
-			proc.Stdout = session
-			proc.Stderr = session.Stderr()
-
-			err = proc.Start()
 			if err != nil {
-				fmt.Fprintln(session.Stderr(), "Error while starting process:", err)
+				fmt.Fprintln(session.Stderr(), err.Error())
 				return
-			}
-			err = proc.Wait()
-			if exit_error, ok := err.(*exec.ExitError); ok {
-				fmt.Fprintln(session.Stderr(), "Process exited with error", exit_error.ExitCode())
-			} else if err != nil {
-				fmt.Fprintln(session.Stderr(), "Error while waiting for process:", err)
 			}
 		},
 		PublicKeyHandler:           func(ctx glider_ssh.Context, key glider_ssh.PublicKey) bool { return true },

-- 
2.48.1