From 02a94b4d90531bca217d6913bd3f1325f3742ff6 Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@lukeshu.com>
Date: Mon, 18 Dec 2017 23:08:41 -0500
Subject: nslcd_systemd: give each connection a unique ID prefix for logging

---
 nslcd_systemd/log.go           | 45 ++++++++++++++++++++++++++++++++++++++++++
 nslcd_systemd/nslcd_systemd.go | 25 +++++++++--------------
 2 files changed, 54 insertions(+), 16 deletions(-)
 create mode 100644 nslcd_systemd/log.go

diff --git a/nslcd_systemd/log.go b/nslcd_systemd/log.go
new file mode 100644
index 0000000..8a646f8
--- /dev/null
+++ b/nslcd_systemd/log.go
@@ -0,0 +1,45 @@
+// Copyright (C) 2017 Luke Shumaker <lukeshu@sbcglobal.net>
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+// 02110-1301 USA
+
+package nslcd_systemd
+
+import (
+	"io"
+
+	"git.lukeshu.com/go/libnslcd/nslcd_server"
+)
+
+type PrefixLogger struct {
+	Prefix string
+	Logger nslcd_server.Logger
+}
+
+func (pl PrefixLogger) Emerg(m string) error   { return pl.Logger.Emerg(pl.Prefix + m) }
+func (pl PrefixLogger) Alert(m string) error   { return pl.Logger.Alert(pl.Prefix + m) }
+func (pl PrefixLogger) Crit(m string) error    { return pl.Logger.Crit(pl.Prefix + m) }
+func (pl PrefixLogger) Err(m string) error     { return pl.Logger.Err(pl.Prefix + m) }
+func (pl PrefixLogger) Warning(m string) error { return pl.Logger.Warning(pl.Prefix + m) }
+func (pl PrefixLogger) Notice(m string) error  { return pl.Logger.Notice(pl.Prefix + m) }
+func (pl PrefixLogger) Info(m string) error    { return pl.Logger.Info(pl.Prefix + m) }
+func (pl PrefixLogger) Debug(m string) error   { return pl.Logger.Debug(pl.Prefix + m) }
+
+func (pl PrefixLogger) Write(m []byte) (int, error) {
+	return pl.Logger.Write(append([]byte(pl.Prefix), m...))
+}
+func (pl PrefixLogger) WriteString(m string) (int, error) {
+	return io.WriteString(pl.Logger, pl.Prefix+m)
+}
diff --git a/nslcd_systemd/nslcd_systemd.go b/nslcd_systemd/nslcd_systemd.go
index 29d49d6..91177a7 100644
--- a/nslcd_systemd/nslcd_systemd.go
+++ b/nslcd_systemd/nslcd_systemd.go
@@ -61,15 +61,6 @@ type Backend interface {
 	Close()
 }
 
-type contextKey struct {
-	name string
-}
-
-var (
-	// ConnectionIDKey is a context key.
-	ConnectionIDKey = &contextKey{"connection-id"}
-)
-
 func get_socket() (socket net.Listener, err error) {
 	fds := sd_daemon.ListenFds(true)
 	if fds == nil {
@@ -106,13 +97,16 @@ func getpeercred(conn *net.UnixConn) (cred unix.Ucred, err error) {
 	return
 }
 
-func handler(backend nslcd_server.Backend, limits nslcd_server.Limits, conn *net.UnixConn, ctx context.Context) {
+func handler(backend nslcd_server.Backend, limits nslcd_server.Limits, conn *net.UnixConn, cid int, ctx context.Context) {
 	defer conn.Close()
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
-	// TODO: override nslcd_server.LoggerKey with a logger that includes ConnectionIDKey
-	log := nslcd_server.LoggerFromContext(ctx)
+	log := PrefixLogger{
+		Prefix: fmt.Sprintf("[%v] ", cid),
+		Logger: nslcd_server.LoggerFromContext(ctx),
+	}
+	ctx = context.WithValue(ctx, nslcd_server.LoggerKey, log)
 
 	cred, err := getpeercred(conn)
 	if err != nil {
@@ -195,12 +189,11 @@ func Main(backend Backend, limits nslcd_server.Limits, ctx context.Context) uint
 			if conn != nil {
 				wg.Add(1)
 				id++
-				hctx := context.WithValue(ctx, ConnectionIDKey, id)
-				go func() {
+				go func(id int) {
 					defer sd_daemon.Recover()
 					defer wg.Done()
-					handler(backend, limits, conn.(*net.UnixConn), hctx)
-				}()
+					handler(backend, limits, conn.(*net.UnixConn), id, ctx)
+				}(id)
 			}
 		}
 	}()
-- 
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