add config file support

1 files changed, 121 insertions, 8 deletions

diff --git a/cmd/tunneld/main.go b/cmd/tunneld/main.go
index 6a16dec..aa0a370 100644
--- a/cmd/tunneld/main.go
+++ b/cmd/tunneld/main.go
@@ -1,13 +1,18 @@
 package main
 
 import (
+	"bufio"
 	"errors"
 	"flag"
+	"fmt"
 	"log"
 	"log/syslog"
 	"os"
 	"os/signal"
+	"os/user"
 	"path"
+	"strconv"
+	"strings"
 	"syscall"
 	"tunnel/pkg/config"
 	"tunnel/pkg/server"
@@ -16,6 +21,7 @@ import (
 var (
 	debugFlag  = flag.Bool("d", false, "debug: print time and source info")
 	syslogFlag = flag.Bool("s", false, "log output to syslog instead of stdout")
+	configFlag = flag.String("c", "", "path to configuration file")
 )
 
 func initLog() {
@@ -51,11 +57,16 @@ func sighandler(c chan os.Signal, s *server.Server) {
 	}
 }
 
+func initSignals(s *server.Server) {
+	var c = make(chan os.Signal)
+
+	signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
+
+	go sighandler(c, s)
+}
+
 func getSocketPath() string {
-	s, err := config.GetSocketPath()
-	if err != nil {
-		log.Fatal(err)
-	}
+	s := config.GetSocketPath()
 
 	if err := os.Mkdir(path.Dir(s), 0700); err != nil {
 		if !errors.Is(err, syscall.EEXIST) {
@@ -66,6 +77,107 @@ func getSocketPath() string {
 	return s
 }
 
+func openConfig() (*os.File, error) {
+	var c string
+
+	if len(*configFlag) > 0 {
+		c = *configFlag
+	} else {
+		c = config.GetConfigPath()
+	}
+
+	if c == "" {
+		return nil, nil
+	}
+
+	fp, err := os.Open(c)
+	if err != nil {
+		if *configFlag == "" && errors.Is(err, syscall.ENOENT) {
+			return nil, nil
+		}
+
+		return nil, err
+	}
+
+	return fp, nil
+}
+
+func readConfig(s *server.Server) error {
+	fp, err := openConfig()
+	if fp == nil || err != nil {
+		return err
+	}
+
+	defer fp.Close()
+
+	scanner := bufio.NewScanner(fp)
+	scanner.Split(bufio.ScanLines)
+
+	for nline := 1; scanner.Scan(); nline++ {
+		args := strings.SplitN(scanner.Text(), "#", 2)
+		cmd := strings.TrimSpace(args[0])
+
+		if cmd == "" {
+			continue
+		}
+
+		if err := s.Command(cmd); err != nil {
+			return fmt.Errorf("%s:%d: %s: %w", fp.Name(), nline, cmd, err)
+		}
+	}
+
+	return nil
+}
+
+func updateSocketGroup(s *server.Server, group string) error {
+	var gid int
+
+	if g, err := user.LookupGroup(group); err != nil {
+		return err
+	} else {
+		var err error
+
+		if gid, err = strconv.Atoi(g.Gid); err != nil {
+			return fmt.Errorf("bad group id %s: %w", g.Gid, err)
+		}
+	}
+
+	f := s.Socket()
+	d := path.Dir(f)
+
+	if err := os.Chown(d, -1, gid); err != nil {
+		return err
+	}
+
+	if err := os.Chmod(d, 0750); err != nil {
+		return err
+	}
+
+	if err := os.Chown(f, -1, gid); err != nil {
+		return err
+	}
+
+	if err := os.Chmod(f, 0770); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func configure(s *server.Server) error {
+	if err := readConfig(s); err != nil {
+		return err
+	}
+
+	if group, ok := s.Env().Find("server.socket.group"); ok {
+		if err := updateSocketGroup(s, group); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 func main() {
 	flag.Parse()
 	initLog()
@@ -75,11 +187,12 @@ func main() {
 		log.Fatal(err)
 	}
 
-	var c = make(chan os.Signal)
-
-	signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
+	if err := configure(s); err != nil {
+		s.Stop()
+		log.Fatal(err)
+	}
 
-	go sighandler(c, s)
+	initSignals(s)
 
 	log.Print("ready")