Add support for extra sendmail arguments (#2731)

* Add support for extra sendmail arguments

* Sendmail args to exec.command should be a list

* Add go-shellquote package

* Use go-shellquote lib for parsing Sendmail args

* Only parse if sendmail is configured

modules/mailer/mailer.go

@@ -209,6 +209,7 @@ func (s *sendmailSender) Send(from string, to []string, msg io.WriterTo) error {
 	var waitError error
 
 	args := []string{"-F", from, "-i"}
+	args = append(args, setting.MailService.SendmailArgs...)
 	args = append(args, to...)
 	log.Trace("Sending with: %s %v", setting.MailService.SendmailPath, args)
 	cmd := exec.Command(setting.MailService.SendmailPath, args...)

modules/setting/setting.go

@@ -35,6 +35,7 @@ import (
 	"github.com/go-macaron/session"
 	_ "github.com/go-macaron/session/redis" // redis plugin for store session
 	"github.com/go-xorm/core"
+	"github.com/kballard/go-shellquote"
 	"gopkg.in/ini.v1"
 	"strk.kbt.io/projects/go/libravatar"
 )
@@ -1326,6 +1327,7 @@ type Mailer struct {
 	// Sendmail sender
 	UseSendmail  bool
 	SendmailPath string
+	SendmailArgs []string
 }
 
 var (
@@ -1372,6 +1374,13 @@ func newMailService() {
 	MailService.FromName = parsed.Name
 	MailService.FromEmail = parsed.Address
 
+	if MailService.UseSendmail {
+		MailService.SendmailArgs, err = shellquote.Split(sec.Key("SENDMAIL_ARGS").String())
+		if err != nil {
+			log.Error(4, "Failed to parse Sendmail args: %v", CustomConf, err)
+		}
+	}
+
 	log.Info("Mail Service Enabled")
 }