Lindenii Project Forge
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server

Lindenii Forge’s main backend daemon
Commit info
ID
72d0c8d9bce125be1b851b142b0f41242d496f6f
Author
Runxi Yu <me@runxiyu.org>
Author date
Sun, 06 Apr 2025 01:24:58 +0800
Committer
Runxi Yu <me@runxiyu.org>
Committer date
Sun, 06 Apr 2025 01:24:58 +0800
Actions
irc: Factor the IRC stuff into its own package
// SPDX-License-Identifier: AGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>

package forge

import (
	"bufio"
	"errors"
	"log/slog"
	"os"

	"go.lindenii.runxiyu.org/forge/internal/database"
	"go.lindenii.runxiyu.org/forge/internal/irc"
	"go.lindenii.runxiyu.org/forge/internal/scfg"
)

type Config struct {
	HTTP struct {
		Net          string `scfg:"net"`
		Addr         string `scfg:"addr"`
		CookieExpiry int    `scfg:"cookie_expiry"`
		Root         string `scfg:"root"`
		ReadTimeout  uint32 `scfg:"read_timeout"`
		WriteTimeout uint32 `scfg:"write_timeout"`
		IdleTimeout  uint32 `scfg:"idle_timeout"`
		ReverseProxy bool   `scfg:"reverse_proxy"`
	} `scfg:"http"`
	Hooks struct {
		Socket string `scfg:"socket"`
		Execs  string `scfg:"execs"`
	} `scfg:"hooks"`
	LMTP struct {
		Socket       string `scfg:"socket"`
		Domain       string `scfg:"domain"`
		MaxSize      int64  `scfg:"max_size"`
		WriteTimeout uint32 `scfg:"write_timeout"`
		ReadTimeout  uint32 `scfg:"read_timeout"`
	} `scfg:"lmtp"`
	Git struct {
		RepoDir    string `scfg:"repo_dir"`
		Socket     string `scfg:"socket"`
		DaemonPath string `scfg:"daemon_path"`
	} `scfg:"git"`
	SSH struct {
		Net  string `scfg:"net"`
		Addr string `scfg:"addr"`
		Key  string `scfg:"key"`
		Root string `scfg:"root"`
	} `scfg:"ssh"`
	IRC struct {
		Net   string `scfg:"net"`
		Addr  string `scfg:"addr"`
		TLS   bool   `scfg:"tls"`
		SendQ uint   `scfg:"sendq"`
		Nick  string `scfg:"nick"`
		User  string `scfg:"user"`
		Gecos string `scfg:"gecos"`
	} `scfg:"irc"`
	IRC     irc.Config `scfg:"irc"`
	General struct {
		Title string `scfg:"title"`
	} `scfg:"general"`
	DB struct {
		Type string `scfg:"type"`
		Conn string `scfg:"conn"`
	} `scfg:"db"`
}

// LoadConfig loads a configuration file from the specified path and unmarshals
// it to the global [config] struct. This may race with concurrent reads from
// [config]; additional synchronization is necessary if the configuration is to
// be made reloadable.
func (s *Server) LoadConfig(path string) (err error) {
	var configFile *os.File
	if configFile, err = os.Open(path); err != nil {
		return err
	}
	defer configFile.Close()

	decoder := scfg.NewDecoder(bufio.NewReader(configFile))
	if err = decoder.Decode(&s.config); err != nil {
		return err
	}
	for _, u := range decoder.UnknownDirectives() {
		slog.Warn("unknown configuration directive", "directive", u)
	}

	if s.config.DB.Type != "postgres" {
		return errors.New("unsupported database type")
	}

	if s.database, err = database.Open(s.config.DB.Conn); err != nil {
		return err
	}

	s.globalData["forge_title"] = s.config.General.Title

	return nil
}
// SPDX-License-Identifier: AGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
//
//go:build linux

package forge

import (
	"bytes"
	"context"
	"encoding/binary"
	"errors"
	"fmt"
	"io"
	"log/slog"
	"net"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"syscall"

	"github.com/go-git/go-git/v5/plumbing"
	"github.com/go-git/go-git/v5/plumbing/object"
	"github.com/jackc/pgx/v5"
	"go.lindenii.runxiyu.org/forge/internal/ansiec"
	"go.lindenii.runxiyu.org/forge/internal/misc"
)

var (
	errGetFD    = errors.New("unable to get file descriptor")
	errGetUcred = errors.New("failed getsockopt")
)

// hooksHandler handles a connection from hookc via the
// unix socket.
func (s *Server) hooksHandler(conn net.Conn) {
	var ctx context.Context
	var cancel context.CancelFunc
	var ucred *syscall.Ucred
	var err error
	var cookie []byte
	var packPass packPass
	var sshStderr io.Writer
	var hookRet byte

	defer conn.Close()
	ctx, cancel = context.WithCancel(context.Background())
	defer cancel()

	// There aren't reasonable cases where someone would run this as
	// another user.
	if ucred, err = getUcred(conn); err != nil {
		if _, err = conn.Write([]byte{1}); err != nil {
			return
		}
		writeRedError(conn, "\nUnable to get peer credentials: %v", err)
		return
	}
	uint32uid := uint32(os.Getuid()) //#nosec G115
	if ucred.Uid != uint32uid {
		if _, err = conn.Write([]byte{1}); err != nil {
			return
		}
		writeRedError(conn, "\nUID mismatch")
		return
	}

	cookie = make([]byte, 64)
	if _, err = conn.Read(cookie); err != nil {
		if _, err = conn.Write([]byte{1}); err != nil {
			return
		}
		writeRedError(conn, "\nFailed to read cookie: %v", err)
		return
	}

	{
		var ok bool
		packPass, ok = s.packPasses.Load(misc.BytesToString(cookie))
		if !ok {
			if _, err = conn.Write([]byte{1}); err != nil {
				return
			}
			writeRedError(conn, "\nInvalid handler cookie")
			return
		}
	}

	sshStderr = packPass.session.Stderr()

	_, _ = sshStderr.Write([]byte{'\n'})

	hookRet = func() byte {
		var argc64 uint64
		if err = binary.Read(conn, binary.NativeEndian, &argc64); err != nil {
			writeRedError(sshStderr, "Failed to read argc: %v", err)
			return 1
		}
		var args []string
		for range argc64 {
			var arg bytes.Buffer
			for {
				nextByte := make([]byte, 1)
				n, err := conn.Read(nextByte)
				if err != nil || n != 1 {
					writeRedError(sshStderr, "Failed to read arg: %v", err)
					return 1
				}
				if nextByte[0] == 0 {
					break
				}
				arg.WriteByte(nextByte[0])
			}
			args = append(args, arg.String())
		}

		gitEnv := make(map[string]string)
		for {
			var envLine bytes.Buffer
			for {
				nextByte := make([]byte, 1)
				n, err := conn.Read(nextByte)
				if err != nil || n != 1 {
					writeRedError(sshStderr, "Failed to read environment variable: %v", err)
					return 1
				}
				if nextByte[0] == 0 {
					break
				}
				envLine.WriteByte(nextByte[0])
			}
			if envLine.Len() == 0 {
				break
			}
			kv := envLine.String()
			parts := strings.SplitN(kv, "=", 2)
			if len(parts) < 2 {
				writeRedError(sshStderr, "Invalid environment variable line: %v", kv)
				return 1
			}
			gitEnv[parts[0]] = parts[1]
		}

		var stdin bytes.Buffer
		if _, err = io.Copy(&stdin, conn); err != nil {
			writeRedError(conn, "Failed to read to the stdin buffer: %v", err)
		}

		switch filepath.Base(args[0]) {
		case "pre-receive":
			if packPass.directAccess {
				return 0
			}
			allOK := true
			for {
				var line, oldOID, rest, newIOID, refName string
				var found bool
				var oldHash, newHash plumbing.Hash
				var oldCommit, newCommit *object.Commit
				var pushOptCount int

				pushOptCount, err = strconv.Atoi(gitEnv["GIT_PUSH_OPTION_COUNT"])
				if err != nil {
					writeRedError(sshStderr, "Failed to parse GIT_PUSH_OPTION_COUNT: %v", err)
					return 1
				}

				// TODO: Allow existing users (even if they are already federated or registered) to add a federated user ID... though perhaps this should be in the normal SSH interface instead of the git push interface?
				// Also it'd be nice to be able to combine users or whatever
				if packPass.contribReq == "federated" && packPass.userType != "federated" && packPass.userType != "registered" {
					if pushOptCount == 0 {
						writeRedError(sshStderr, "This repo requires contributors to be either federated or registered users. You must supply your federated user ID as a push option. For example, git push -o fedid=sr.ht:runxiyu")
						return 1
					}
					for pushOptIndex := range pushOptCount {
						pushOpt, ok := gitEnv[fmt.Sprintf("GIT_PUSH_OPTION_%d", pushOptIndex)]
						if !ok {
							writeRedError(sshStderr, "Failed to get push option %d", pushOptIndex)
							return 1
						}
						if strings.HasPrefix(pushOpt, "fedid=") {
							fedUserID := strings.TrimPrefix(pushOpt, "fedid=")
							service, username, found := strings.Cut(fedUserID, ":")
							if !found {
								writeRedError(sshStderr, "Invalid federated user identifier %#v does not contain a colon", fedUserID)
								return 1
							}

							ok, err := s.fedauth(ctx, packPass.userID, service, username, packPass.pubkey)
							if err != nil {
								writeRedError(sshStderr, "Failed to verify federated user identifier %#v: %v", fedUserID, err)
								return 1
							}
							if !ok {
								writeRedError(sshStderr, "Failed to verify federated user identifier %#v: you don't seem to be on the list", fedUserID)
								return 1
							}

							break
						}
						if pushOptIndex == pushOptCount-1 {
							writeRedError(sshStderr, "This repo requires contributors to be either federated or registered users. You must supply your federated user ID as a push option. For example, git push -o fedid=sr.ht:runxiyu")
							return 1
						}
					}
				}

				line, err = stdin.ReadString('\n')
				if errors.Is(err, io.EOF) {
					break
				} else if err != nil {
					writeRedError(sshStderr, "Failed to read pre-receive line: %v", err)
					return 1
				}
				line = line[:len(line)-1]

				oldOID, rest, found = strings.Cut(line, " ")
				if !found {
					writeRedError(sshStderr, "Invalid pre-receive line: %v", line)
					return 1
				}

				newIOID, refName, found = strings.Cut(rest, " ")
				if !found {
					writeRedError(sshStderr, "Invalid pre-receive line: %v", line)
					return 1
				}

				if strings.HasPrefix(refName, "refs/heads/contrib/") {
					if allZero(oldOID) { // New branch
						fmt.Fprintln(sshStderr, ansiec.Blue+"POK"+ansiec.Reset, refName)
						var newMRLocalID int

						if packPass.userID != 0 {
							err = s.database.QueryRow(ctx,
								"INSERT INTO merge_requests (repo_id, creator, source_ref, status) VALUES ($1, $2, $3, 'open') RETURNING repo_local_id",
								packPass.repoID, packPass.userID, strings.TrimPrefix(refName, "refs/heads/"),
							).Scan(&newMRLocalID)
						} else {
							err = s.database.QueryRow(ctx,
								"INSERT INTO merge_requests (repo_id, source_ref, status) VALUES ($1, $2, 'open') RETURNING repo_local_id",
								packPass.repoID, strings.TrimPrefix(refName, "refs/heads/"),
							).Scan(&newMRLocalID)
						}
						if err != nil {
							writeRedError(sshStderr, "Error creating merge request: %v", err)
							return 1
						}
						mergeRequestWebURL := fmt.Sprintf("%s/contrib/%d/", s.genHTTPRemoteURL(packPass.groupPath, packPass.repoName), newMRLocalID)
						fmt.Fprintln(sshStderr, ansiec.Blue+"Created merge request at", mergeRequestWebURL+ansiec.Reset)

						select {
						case s.ircSendBuffered <- "PRIVMSG #chat :New merge request at " + mergeRequestWebURL:
						default:
							slog.Error("IRC SendQ exceeded")
						}
						s.ircBot.Send("PRIVMSG #chat :New merge request at " + mergeRequestWebURL)
					} else { // Existing contrib branch
						var existingMRUser int
						var isAncestor bool

						err = s.database.QueryRow(ctx,
							"SELECT COALESCE(creator, 0) FROM merge_requests WHERE source_ref = $1 AND repo_id = $2",
							strings.TrimPrefix(refName, "refs/heads/"), packPass.repoID,
						).Scan(&existingMRUser)
						if err != nil {
							if errors.Is(err, pgx.ErrNoRows) {
								writeRedError(sshStderr, "No existing merge request for existing contrib branch: %v", err)
							} else {
								writeRedError(sshStderr, "Error querying for existing merge request: %v", err)
							}
							return 1
						}
						if existingMRUser == 0 {
							allOK = false
							fmt.Fprintln(sshStderr, ansiec.Red+"NAK"+ansiec.Reset, refName, "(branch belongs to unowned MR)")
							continue
						}

						if existingMRUser != packPass.userID {
							allOK = false
							fmt.Fprintln(sshStderr, ansiec.Red+"NAK"+ansiec.Reset, refName, "(branch belongs another user's MR)")
							continue
						}

						oldHash = plumbing.NewHash(oldOID)

						if oldCommit, err = packPass.repo.CommitObject(oldHash); err != nil {
							writeRedError(sshStderr, "Daemon failed to get old commit: %v", err)
							return 1
						}

						// Potential BUG: I'm not sure if new_commit is guaranteed to be
						// detectable as they haven't been merged into the main repo's
						// objects yet. But it seems to work, and I don't think there's
						// any reason for this to only work intermitently.
						newHash = plumbing.NewHash(newIOID)
						if newCommit, err = packPass.repo.CommitObject(newHash); err != nil {
							writeRedError(sshStderr, "Daemon failed to get new commit: %v", err)
							return 1
						}

						if isAncestor, err = oldCommit.IsAncestor(newCommit); err != nil {
							writeRedError(sshStderr, "Daemon failed to check if old commit is ancestor: %v", err)
							return 1
						}

						if !isAncestor {
							// TODO: Create MR snapshot ref instead
							allOK = false
							fmt.Fprintln(sshStderr, ansiec.Red+"NAK"+ansiec.Reset, refName, "(force pushes are not supported yet)")
							continue
						}

						fmt.Fprintln(sshStderr, ansiec.Blue+"POK"+ansiec.Reset, refName)
					}
				} else { // Non-contrib branch
					allOK = false
					fmt.Fprintln(sshStderr, ansiec.Red+"NAK"+ansiec.Reset, refName, "(you cannot push to branches outside of contrib/*)")
				}
			}

			fmt.Fprintln(sshStderr)
			if allOK {
				fmt.Fprintln(sshStderr, "Overall "+ansiec.Green+"ACK"+ansiec.Reset+" (all checks passed)")
				return 0
			}
			fmt.Fprintln(sshStderr, "Overall "+ansiec.Red+"NAK"+ansiec.Reset+" (one or more branches failed checks)")
			return 1
		default:
			fmt.Fprintln(sshStderr, ansiec.Red+"Invalid hook:", args[0]+ansiec.Reset)
			return 1
		}
	}()

	fmt.Fprintln(sshStderr)

	_, _ = conn.Write([]byte{hookRet})
}

// serveGitHooks handles connections on the specified network listener and
// treats incoming connections as those from git hook handlers by spawning
// sessions. The listener must be a SOCK_STREAM UNIX domain socket. The
// function itself blocks.
func (s *Server) serveGitHooks(listener net.Listener) error {
	for {
		conn, err := listener.Accept()
		if err != nil {
			return err
		}
		go s.hooksHandler(conn)
	}
}

// getUcred fetches connection credentials as a [syscall.Ucred] from a given
// [net.Conn]. It panics when conn is not a [net.UnixConn].
func getUcred(conn net.Conn) (ucred *syscall.Ucred, err error) {
	unixConn := conn.(*net.UnixConn)
	var unixConnFD *os.File

	if unixConnFD, err = unixConn.File(); err != nil {
		return nil, errGetFD
	}
	defer unixConnFD.Close()

	if ucred, err = syscall.GetsockoptUcred(int(unixConnFD.Fd()), syscall.SOL_SOCKET, syscall.SO_PEERCRED); err != nil {
		return nil, errGetUcred
	}
	return ucred, nil
}

// allZero returns true if all runes in a given string are '0'. The comparison
// is not constant time and must not be used in contexts where time-based side
// channel attacks are a concern.
func allZero(s string) bool {
	for _, r := range s {
		if r != '0' {
			return false
		}
	}
	return true
}
// SPDX-License-Identifier: AGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
//
//go:build !linux

package forge

import (
	"bytes"
	"context"
	"encoding/binary"
	"errors"
	"fmt"
	"io"
	"log/slog"
	"net"
	"path/filepath"
	"strconv"
	"strings"

	"github.com/go-git/go-git/v5/plumbing"
	"github.com/go-git/go-git/v5/plumbing/object"
	"github.com/jackc/pgx/v5"
	"go.lindenii.runxiyu.org/forge/internal/ansiec"
	"go.lindenii.runxiyu.org/forge/internal/misc"
)

// hooksHandler handles a connection from hookc via the
// unix socket.
func (s *Server) hooksHandler(conn net.Conn) {
	var ctx context.Context
	var cancel context.CancelFunc
	var err error
	var cookie []byte
	var packPass packPass
	var sshStderr io.Writer
	var hookRet byte

	defer conn.Close()
	ctx, cancel = context.WithCancel(context.Background())
	defer cancel()

	// TODO: ucred-like checks

	cookie = make([]byte, 64)
	if _, err = conn.Read(cookie); err != nil {
		if _, err = conn.Write([]byte{1}); err != nil {
			return
		}
		writeRedError(conn, "\nFailed to read cookie: %v", err)
		return
	}

	{
		var ok bool
		packPass, ok = s.packPasses.Load(misc.BytesToString(cookie))
		if !ok {
			if _, err = conn.Write([]byte{1}); err != nil {
				return
			}
			writeRedError(conn, "\nInvalid handler cookie")
			return
		}
	}

	sshStderr = packPass.session.Stderr()

	_, _ = sshStderr.Write([]byte{'\n'})

	hookRet = func() byte {
		var argc64 uint64
		if err = binary.Read(conn, binary.NativeEndian, &argc64); err != nil {
			writeRedError(sshStderr, "Failed to read argc: %v", err)
			return 1
		}
		var args []string
		for range argc64 {
			var arg bytes.Buffer
			for {
				nextByte := make([]byte, 1)
				n, err := conn.Read(nextByte)
				if err != nil || n != 1 {
					writeRedError(sshStderr, "Failed to read arg: %v", err)
					return 1
				}
				if nextByte[0] == 0 {
					break
				}
				arg.WriteByte(nextByte[0])
			}
			args = append(args, arg.String())
		}

		gitEnv := make(map[string]string)
		for {
			var envLine bytes.Buffer
			for {
				nextByte := make([]byte, 1)
				n, err := conn.Read(nextByte)
				if err != nil || n != 1 {
					writeRedError(sshStderr, "Failed to read environment variable: %v", err)
					return 1
				}
				if nextByte[0] == 0 {
					break
				}
				envLine.WriteByte(nextByte[0])
			}
			if envLine.Len() == 0 {
				break
			}
			kv := envLine.String()
			parts := strings.SplitN(kv, "=", 2)
			if len(parts) < 2 {
				writeRedError(sshStderr, "Invalid environment variable line: %v", kv)
				return 1
			}
			gitEnv[parts[0]] = parts[1]
		}

		var stdin bytes.Buffer
		if _, err = io.Copy(&stdin, conn); err != nil {
			writeRedError(conn, "Failed to read to the stdin buffer: %v", err)
		}

		switch filepath.Base(args[0]) {
		case "pre-receive":
			if packPass.directAccess {
				return 0
			}
			allOK := true
			for {
				var line, oldOID, rest, newIOID, refName string
				var found bool
				var oldHash, newHash plumbing.Hash
				var oldCommit, newCommit *object.Commit
				var pushOptCount int

				pushOptCount, err = strconv.Atoi(gitEnv["GIT_PUSH_OPTION_COUNT"])
				if err != nil {
					writeRedError(sshStderr, "Failed to parse GIT_PUSH_OPTION_COUNT: %v", err)
					return 1
				}

				// TODO: Allow existing users (even if they are already federated or registered) to add a federated user ID... though perhaps this should be in the normal SSH interface instead of the git push interface?
				// Also it'd be nice to be able to combine users or whatever
				if packPass.contribReq == "federated" && packPass.userType != "federated" && packPass.userType != "registered" {
					if pushOptCount == 0 {
						writeRedError(sshStderr, "This repo requires contributors to be either federated or registered users. You must supply your federated user ID as a push option. For example, git push -o fedid=sr.ht:runxiyu")
						return 1
					}
					for pushOptIndex := range pushOptCount {
						pushOpt, ok := gitEnv[fmt.Sprintf("GIT_PUSH_OPTION_%d", pushOptIndex)]
						if !ok {
							writeRedError(sshStderr, "Failed to get push option %d", pushOptIndex)
							return 1
						}
						if strings.HasPrefix(pushOpt, "fedid=") {
							fedUserID := strings.TrimPrefix(pushOpt, "fedid=")
							service, username, found := strings.Cut(fedUserID, ":")
							if !found {
								writeRedError(sshStderr, "Invalid federated user identifier %#v does not contain a colon", fedUserID)
								return 1
							}

							ok, err := s.fedauth(ctx, packPass.userID, service, username, packPass.pubkey)
							if err != nil {
								writeRedError(sshStderr, "Failed to verify federated user identifier %#v: %v", fedUserID, err)
								return 1
							}
							if !ok {
								writeRedError(sshStderr, "Failed to verify federated user identifier %#v: you don't seem to be on the list", fedUserID)
								return 1
							}

							break
						}
						if pushOptIndex == pushOptCount-1 {
							writeRedError(sshStderr, "This repo requires contributors to be either federated or registered users. You must supply your federated user ID as a push option. For example, git push -o fedid=sr.ht:runxiyu")
							return 1
						}
					}
				}

				line, err = stdin.ReadString('\n')
				if errors.Is(err, io.EOF) {
					break
				} else if err != nil {
					writeRedError(sshStderr, "Failed to read pre-receive line: %v", err)
					return 1
				}
				line = line[:len(line)-1]

				oldOID, rest, found = strings.Cut(line, " ")
				if !found {
					writeRedError(sshStderr, "Invalid pre-receive line: %v", line)
					return 1
				}

				newIOID, refName, found = strings.Cut(rest, " ")
				if !found {
					writeRedError(sshStderr, "Invalid pre-receive line: %v", line)
					return 1
				}

				if strings.HasPrefix(refName, "refs/heads/contrib/") {
					if allZero(oldOID) { // New branch
						fmt.Fprintln(sshStderr, ansiec.Blue+"POK"+ansiec.Reset, refName)
						var newMRLocalID int

						if packPass.userID != 0 {
							err = s.database.QueryRow(ctx,
								"INSERT INTO merge_requests (repo_id, creator, source_ref, status) VALUES ($1, $2, $3, 'open') RETURNING repo_local_id",
								packPass.repoID, packPass.userID, strings.TrimPrefix(refName, "refs/heads/"),
							).Scan(&newMRLocalID)
						} else {
							err = s.database.QueryRow(ctx,
								"INSERT INTO merge_requests (repo_id, source_ref, status) VALUES ($1, $2, 'open') RETURNING repo_local_id",
								packPass.repoID, strings.TrimPrefix(refName, "refs/heads/"),
							).Scan(&newMRLocalID)
						}
						if err != nil {
							writeRedError(sshStderr, "Error creating merge request: %v", err)
							return 1
						}
						mergeRequestWebURL := fmt.Sprintf("%s/contrib/%d/", s.genHTTPRemoteURL(packPass.groupPath, packPass.repoName), newMRLocalID)
						fmt.Fprintln(sshStderr, ansiec.Blue+"Created merge request at", mergeRequestWebURL+ansiec.Reset)

						select {
						case s.ircSendBuffered <- "PRIVMSG #chat :New merge request at " + mergeRequestWebURL:
						default:
							slog.Error("IRC SendQ exceeded")
						}
						s.ircBot.Send("PRIVMSG #chat :New merge request at " + mergeRequestWebURL)
					} else { // Existing contrib branch
						var existingMRUser int
						var isAncestor bool

						err = s.database.QueryRow(ctx,
							"SELECT COALESCE(creator, 0) FROM merge_requests WHERE source_ref = $1 AND repo_id = $2",
							strings.TrimPrefix(refName, "refs/heads/"), packPass.repoID,
						).Scan(&existingMRUser)
						if err != nil {
							if errors.Is(err, pgx.ErrNoRows) {
								writeRedError(sshStderr, "No existing merge request for existing contrib branch: %v", err)
							} else {
								writeRedError(sshStderr, "Error querying for existing merge request: %v", err)
							}
							return 1
						}
						if existingMRUser == 0 {
							allOK = false
							fmt.Fprintln(sshStderr, ansiec.Red+"NAK"+ansiec.Reset, refName, "(branch belongs to unowned MR)")
							continue
						}

						if existingMRUser != packPass.userID {
							allOK = false
							fmt.Fprintln(sshStderr, ansiec.Red+"NAK"+ansiec.Reset, refName, "(branch belongs another user's MR)")
							continue
						}

						oldHash = plumbing.NewHash(oldOID)

						if oldCommit, err = packPass.repo.CommitObject(oldHash); err != nil {
							writeRedError(sshStderr, "Daemon failed to get old commit: %v", err)
							return 1
						}

						// Potential BUG: I'm not sure if new_commit is guaranteed to be
						// detectable as they haven't been merged into the main repo's
						// objects yet. But it seems to work, and I don't think there's
						// any reason for this to only work intermitently.
						newHash = plumbing.NewHash(newIOID)
						if newCommit, err = packPass.repo.CommitObject(newHash); err != nil {
							writeRedError(sshStderr, "Daemon failed to get new commit: %v", err)
							return 1
						}

						if isAncestor, err = oldCommit.IsAncestor(newCommit); err != nil {
							writeRedError(sshStderr, "Daemon failed to check if old commit is ancestor: %v", err)
							return 1
						}

						if !isAncestor {
							// TODO: Create MR snapshot ref instead
							allOK = false
							fmt.Fprintln(sshStderr, ansiec.Red+"NAK"+ansiec.Reset, refName, "(force pushes are not supported yet)")
							continue
						}

						fmt.Fprintln(sshStderr, ansiec.Blue+"POK"+ansiec.Reset, refName)
					}
				} else { // Non-contrib branch
					allOK = false
					fmt.Fprintln(sshStderr, ansiec.Red+"NAK"+ansiec.Reset, refName, "(you cannot push to branches outside of contrib/*)")
				}
			}

			fmt.Fprintln(sshStderr)
			if allOK {
				fmt.Fprintln(sshStderr, "Overall "+ansiec.Green+"ACK"+ansiec.Reset+" (all checks passed)")
				return 0
			}
			fmt.Fprintln(sshStderr, "Overall "+ansiec.Red+"NAK"+ansiec.Reset+" (one or more branches failed checks)")
			return 1
		default:
			fmt.Fprintln(sshStderr, ansiec.Red+"Invalid hook:", args[0]+ansiec.Reset)
			return 1
		}
	}()

	fmt.Fprintln(sshStderr)

	_, _ = conn.Write([]byte{hookRet})
}

// serveGitHooks handles connections on the specified network listener and
// treats incoming connections as those from git hook handlers by spawning
// sessions. The listener must be a SOCK_STREAM UNIX domain socket. The
// function itself blocks.
func (s *Server) serveGitHooks(listener net.Listener) error {
	for {
		conn, err := listener.Accept()
		if err != nil {
			return err
		}
		go s.hooksHandler(conn)
	}
}

// allZero returns true if all runes in a given string are '0'. The comparison
// is not constant time and must not be used in contexts where time-based side
// channel attacks are a concern.
func allZero(s string) bool {
	for _, r := range s {
		if r != '0' {
			return false
		}
	}
	return true
}
package irc

import (
	"crypto/tls"
	"log/slog"
	"net"

	"go.lindenii.runxiyu.org/forge/internal/misc"
	irc "go.lindenii.runxiyu.org/lindenii-irc"
)

type Config struct {
	Net   string `scfg:"net"`
	Addr  string `scfg:"addr"`
	TLS   bool   `scfg:"tls"`
	SendQ uint   `scfg:"sendq"`
	Nick  string `scfg:"nick"`
	User  string `scfg:"user"`
	Gecos string `scfg:"gecos"`
}

type Bot struct {
	config            *Config
	ircSendBuffered   chan string
	ircSendDirectChan chan misc.ErrorBack[string]
}

func NewBot(c *Config) (b *Bot) {
	b = &Bot{
		config: c,
	}
	return
}

func (b *Bot) Connect() error {
	var err error
	var underlyingConn net.Conn
	if b.config.TLS {
		underlyingConn, err = tls.Dial(b.config.Net, b.config.Addr, nil)
	} else {
		underlyingConn, err = net.Dial(b.config.Net, b.config.Addr)
	}
	if err != nil {
		return err
	}
	defer underlyingConn.Close()

	conn := irc.NewConn(underlyingConn)

	logAndWriteLn := func(s string) (n int, err error) {
		slog.Debug("irc tx", "line", s)
		return conn.WriteString(s + "\r\n")
	}

	_, err = logAndWriteLn("NICK " + b.config.Nick)
	if err != nil {
		return err
	}
	_, err = logAndWriteLn("USER " + b.config.User + " 0 * :" + b.config.Gecos)
	if err != nil {
		return err
	}

	readLoopError := make(chan error)
	writeLoopAbort := make(chan struct{})
	go func() {
		for {
			select {
			case <-writeLoopAbort:
				return
			default:
			}

			msg, line, err := conn.ReadMessage()
			if err != nil {
				readLoopError <- err
				return
			}

			slog.Debug("irc rx", "line", line)

			switch msg.Command {
			case "001":
				_, err = logAndWriteLn("JOIN #chat")
				if err != nil {
					readLoopError <- err
					return
				}
			case "PING":
				_, err = logAndWriteLn("PONG :" + msg.Args[0])
				if err != nil {
					readLoopError <- err
					return
				}
			case "JOIN":
				c, ok := msg.Source.(irc.Client)
				if !ok {
					slog.Error("unable to convert source of JOIN to client")
				}
				if c.Nick != b.config.Nick {
					continue
				}
			default:
			}
		}
	}()

	for {
		select {
		case err = <-readLoopError:
			return err
		case line := <-b.ircSendBuffered:
			_, err = logAndWriteLn(line)
			if err != nil {
				select {
				case b.ircSendBuffered <- line:
				default:
					slog.Error("unable to requeue message", "line", line)
				}
				writeLoopAbort <- struct{}{}
				return err
			}
		case lineErrorBack := <-b.ircSendDirectChan:
			_, err = logAndWriteLn(lineErrorBack.Content)
			lineErrorBack.ErrorChan <- err
			if err != nil {
				writeLoopAbort <- struct{}{}
				return err
			}
		}
	}
}

// SendDirect sends an IRC message directly to the connection and bypasses
// the buffering system.
func (b *Bot) SendDirect(line string) error {
	ech := make(chan error, 1)

	b.ircSendDirectChan <- misc.ErrorBack[string]{
		Content:   line,
		ErrorChan: ech,
	}

	return <-ech
}

func (b *Bot) Send(line string) {
	select {
	case b.ircSendBuffered <- line:
	default:
		slog.Error("irc sendq full", "line", line)
	}
}

// TODO: Delay and warnings?
func (b *Bot) ConnectLoop() {
	b.ircSendBuffered = make(chan string, b.config.SendQ)
	b.ircSendDirectChan = make(chan misc.ErrorBack[string])

	for {
		err := b.Connect()
		slog.Error("irc session error", "error", err)
	}
}
package misc

type ErrorBack[T any] struct {
	Content   T
	ErrorChan chan error
}
// SPDX-License-Identifier: AGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>

package forge

import (
	"crypto/tls"
	"log/slog"
	"net"

	irc "go.lindenii.runxiyu.org/lindenii-irc"
)

type errorBack[T any] struct {
	content   T
	errorBack chan error
}

func (s *Server) ircBotSession() error {
	var err error
	var underlyingConn net.Conn
	if s.config.IRC.TLS {
		underlyingConn, err = tls.Dial(s.config.IRC.Net, s.config.IRC.Addr, nil)
	} else {
		underlyingConn, err = net.Dial(s.config.IRC.Net, s.config.IRC.Addr)
	}
	if err != nil {
		return err
	}
	defer underlyingConn.Close()

	conn := irc.NewConn(underlyingConn)

	logAndWriteLn := func(s string) (n int, err error) {
		slog.Debug("irc tx", "line", s)
		return conn.WriteString(s + "\r\n")
	}

	_, err = logAndWriteLn("NICK " + s.config.IRC.Nick)
	if err != nil {
		return err
	}
	_, err = logAndWriteLn("USER " + s.config.IRC.User + " 0 * :" + s.config.IRC.Gecos)
	if err != nil {
		return err
	}

	readLoopError := make(chan error)
	writeLoopAbort := make(chan struct{})
	go func() {
		for {
			select {
			case <-writeLoopAbort:
				return
			default:
			}

			msg, line, err := conn.ReadMessage()
			if err != nil {
				readLoopError <- err
				return
			}

			slog.Debug("irc rx", "line", line)

			switch msg.Command {
			case "001":
				_, err = logAndWriteLn("JOIN #chat")
				if err != nil {
					readLoopError <- err
					return
				}
			case "PING":
				_, err = logAndWriteLn("PONG :" + msg.Args[0])
				if err != nil {
					readLoopError <- err
					return
				}
			case "JOIN":
				c, ok := msg.Source.(irc.Client)
				if !ok {
					slog.Error("unable to convert source of JOIN to client")
				}
				if c.Nick != s.config.IRC.Nick {
					continue
				}
			default:
			}
		}
	}()

	for {
		select {
		case err = <-readLoopError:
			return err
		case line := <-s.ircSendBuffered:
			_, err = logAndWriteLn(line)
			if err != nil {
				select {
				case s.ircSendBuffered <- line:
				default:
					slog.Error("unable to requeue message", "line", line)
				}
				writeLoopAbort <- struct{}{}
				return err
			}
		case lineErrorBack := <-s.ircSendDirectChan:
			_, err = logAndWriteLn(lineErrorBack.content)
			lineErrorBack.errorBack <- err
			if err != nil {
				writeLoopAbort <- struct{}{}
				return err
			}
		}
	}
}

// ircSendDirect sends an IRC message directly to the connection and bypasses
// the buffering system.
func (s *Server) ircSendDirect(line string) error {
	ech := make(chan error, 1)

	s.ircSendDirectChan <- errorBack[string]{
		content:   line,
		errorBack: ech,
	}

	return <-ech
}

// TODO: Delay and warnings?
func (s *Server) ircBotLoop() {
	s.ircSendBuffered = make(chan string, s.config.IRC.SendQ)
	s.ircSendDirectChan = make(chan errorBack[string])

	for {
		err := s.ircBotSession()
		slog.Error("irc session error", "error", err)
	}
}
// SPDX-License-Identifier: AGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>

package forge

import (
	"errors"
	"html/template"
	"io/fs"
	"log"
	"log/slog"
	"net"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"syscall"
	"time"

	"go.lindenii.runxiyu.org/forge/internal/database"
	"go.lindenii.runxiyu.org/forge/internal/irc"
	"go.lindenii.runxiyu.org/forge/internal/misc"
	"go.lindenii.runxiyu.org/lindenii-common/cmap"
	goSSH "golang.org/x/crypto/ssh"
)

type Server struct {
	config Config

	database database.Database

	sourceHandler http.Handler
	staticHandler http.Handler

	ircSendBuffered   chan string
	ircSendDirectChan chan errorBack[string]

	// globalData is passed as "global" when rendering HTML templates.
	globalData map[string]any

	serverPubkeyString string
	serverPubkeyFP     string
	serverPubkey       goSSH.PublicKey

	// packPasses contains hook cookies mapped to their packPass.
	packPasses cmap.Map[string, packPass]

	templates *template.Template

	ircBot *irc.Bot
}

func (s *Server) Setup() {
	s.sourceHandler = http.StripPrefix(
		"/-/source/",
		http.FileServer(http.FS(embeddedSourceFS)),
	)
	staticFS, err := fs.Sub(embeddedResourcesFS, "static")
	if err != nil {
		panic(err)
	}
	s.staticHandler = http.StripPrefix("/-/static/", http.FileServer(http.FS(staticFS)))
	s.globalData = map[string]any{
		"server_public_key_string":      &s.serverPubkeyString,
		"server_public_key_fingerprint": &s.serverPubkeyFP,
		"forge_version":                 version,
		// Some other ones are populated after config parsing
	}
}

func (s *Server) Run() {
	misc.NoneOrPanic(s.loadTemplates())
	misc.NoneOrPanic(misc.DeployBinary(misc.FirstOrPanic(embeddedResourcesFS.Open("git2d/git2d")), s.config.Git.DaemonPath))
	misc.NoneOrPanic(misc.DeployBinary(misc.FirstOrPanic(embeddedResourcesFS.Open("hookc/hookc")), filepath.Join(s.config.Hooks.Execs, "pre-receive")))
	misc.NoneOrPanic(os.Chmod(filepath.Join(s.config.Hooks.Execs, "pre-receive"), 0o755))

	// Launch Git2D
	go func() {
		cmd := exec.Command(s.config.Git.DaemonPath, s.config.Git.Socket) //#nosec G204
		cmd.Stderr = log.Writer()
		cmd.Stdout = log.Writer()
		if err := cmd.Run(); err != nil {
			panic(err)
		}
	}()

	// UNIX socket listener for hooks
	{
		hooksListener, err := net.Listen("unix", s.config.Hooks.Socket)
		if errors.Is(err, syscall.EADDRINUSE) {
			slog.Warn("removing existing socket", "path", s.config.Hooks.Socket)
			if err = syscall.Unlink(s.config.Hooks.Socket); err != nil {
				slog.Error("removing existing socket", "path", s.config.Hooks.Socket, "error", err)
				os.Exit(1)
			}
			if hooksListener, err = net.Listen("unix", s.config.Hooks.Socket); err != nil {
				slog.Error("listening hooks", "error", err)
				os.Exit(1)
			}
		} else if err != nil {
			slog.Error("listening hooks", "error", err)
			os.Exit(1)
		}
		slog.Info("listening hooks on unix", "path", s.config.Hooks.Socket)
		go func() {
			if err = s.serveGitHooks(hooksListener); err != nil {
				slog.Error("serving hooks", "error", err)
				os.Exit(1)
			}
		}()
	}

	// UNIX socket listener for LMTP
	{
		lmtpListener, err := net.Listen("unix", s.config.LMTP.Socket)
		if errors.Is(err, syscall.EADDRINUSE) {
			slog.Warn("removing existing socket", "path", s.config.LMTP.Socket)
			if err = syscall.Unlink(s.config.LMTP.Socket); err != nil {
				slog.Error("removing existing socket", "path", s.config.LMTP.Socket, "error", err)
				os.Exit(1)
			}
			if lmtpListener, err = net.Listen("unix", s.config.LMTP.Socket); err != nil {
				slog.Error("listening LMTP", "error", err)
				os.Exit(1)
			}
		} else if err != nil {
			slog.Error("listening LMTP", "error", err)
			os.Exit(1)
		}
		slog.Info("listening LMTP on unix", "path", s.config.LMTP.Socket)
		go func() {
			if err = s.serveLMTP(lmtpListener); err != nil {
				slog.Error("serving LMTP", "error", err)
				os.Exit(1)
			}
		}()
	}

	// SSH listener
	{
		sshListener, err := net.Listen(s.config.SSH.Net, s.config.SSH.Addr)
		if errors.Is(err, syscall.EADDRINUSE) && s.config.SSH.Net == "unix" {
			slog.Warn("removing existing socket", "path", s.config.SSH.Addr)
			if err = syscall.Unlink(s.config.SSH.Addr); err != nil {
				slog.Error("removing existing socket", "path", s.config.SSH.Addr, "error", err)
				os.Exit(1)
			}
			if sshListener, err = net.Listen(s.config.SSH.Net, s.config.SSH.Addr); err != nil {
				slog.Error("listening SSH", "error", err)
				os.Exit(1)
			}
		} else if err != nil {
			slog.Error("listening SSH", "error", err)
			os.Exit(1)
		}
		slog.Info("listening SSH on", "net", s.config.SSH.Net, "addr", s.config.SSH.Addr)
		go func() {
			if err = s.serveSSH(sshListener); err != nil {
				slog.Error("serving SSH", "error", err)
				os.Exit(1)
			}
		}()
	}

	// HTTP listener
	{
		httpListener, err := net.Listen(s.config.HTTP.Net, s.config.HTTP.Addr)
		if errors.Is(err, syscall.EADDRINUSE) && s.config.HTTP.Net == "unix" {
			slog.Warn("removing existing socket", "path", s.config.HTTP.Addr)
			if err = syscall.Unlink(s.config.HTTP.Addr); err != nil {
				slog.Error("removing existing socket", "path", s.config.HTTP.Addr, "error", err)
				os.Exit(1)
			}
			if httpListener, err = net.Listen(s.config.HTTP.Net, s.config.HTTP.Addr); err != nil {
				slog.Error("listening HTTP", "error", err)
				os.Exit(1)
			}
		} else if err != nil {
			slog.Error("listening HTTP", "error", err)
			os.Exit(1)
		}
		server := http.Server{
			Handler:      s,
			ReadTimeout:  time.Duration(s.config.HTTP.ReadTimeout) * time.Second,
			WriteTimeout: time.Duration(s.config.HTTP.ReadTimeout) * time.Second,
			IdleTimeout:  time.Duration(s.config.HTTP.ReadTimeout) * time.Second,
		} //exhaustruct:ignore
		slog.Info("listening HTTP on", "net", s.config.HTTP.Net, "addr", s.config.HTTP.Addr)
		go func() {
			if err = server.Serve(httpListener); err != nil && !errors.Is(err, http.ErrServerClosed) {
				slog.Error("serving HTTP", "error", err)
				os.Exit(1)
			}
		}()
	}

	// IRC bot
	go s.ircBotLoop()
	go s.ircBot.ConnectLoop()

	select {}
}