nslcd_proto: BREAKING CHANGE: Rethink the panic strategy

nslcd_proto.Read() and .Write() panic() with any errors that they may
need to emit.  This made composition really simple, I was OK with it
being against the normal Go style.

But, I'm not happy with it anymore; have them return errors now.

This leads us in to nslcd_server.HandleRequest() using those panics
for control flow.  Add a maybePanic(error) function to wrap all of the
proto.Read() and proto.Write() calls to restore the panicing behavior.

1 files changed, 16 insertions, 10 deletions

diff --git a/nslcd_server/func_handlerequest.go.gen b/nslcd_server/func_handlerequest.go.gen
index e7e2dcc..40e00c0 100755
--- a/nslcd_server/func_handlerequest.go.gen
+++ b/nslcd_server/func_handlerequest.go.gen
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 # -*- Mode: Go -*-
-# Copyright (C) 2015-2016 Luke Shumaker <lukeshu@sbcglobal.net>
+# Copyright (C) 2015-2017 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
@@ -35,12 +35,18 @@ import (
 
 const sensitive = "<omitted-from-log>"
 
+func maybePanic(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
 // Handle a request to nslcd
 func HandleRequest(backend Backend, in io.Reader, out io.Writer, cred unix.Ucred) (err error) {
 	defer func() {
 		if r := recover(); r != nil {
 			switch r := r.(type) {
-			case error:
+			case p.NslcdError:
 				err = r
 			default:
 				panic(r)
@@ -53,12 +59,12 @@ func HandleRequest(backend Backend, in io.Reader, out io.Writer, cred unix.Ucred
 
 func handleRequest(backend Backend, in io.Reader, out io.Writer, cred unix.Ucred) {
 	var version int32
-	p.Read(in, &version)
+	maybePanic(p.Read(in, &version))
 	if version != p.NSLCD_VERSION {
 		panic(p.NslcdError(fmt.Sprintf("Version mismatch: server=%#08x client=%#08x", p.NSLCD_VERSION, version)))
 	}
 	var action int32
-	p.Read(in, &action)
+	maybePanic(p.Read(in, &action))
 
 	ch := make(chan interface{})
 	switch action {
@@ -67,7 +73,7 @@ while read -r request; do
 	cat <<EOT
 	case p.NSLCD_ACTION_${request^^}:
 		var req p.Request_${request}
-		p.Read(in, &req)
+		maybePanic(p.Read(in, &req))
 		$(
 		case "$request" in
 			PAM_Authentication)
@@ -107,13 +113,13 @@ done < "$requests"
 		close(ch)
 		panic(p.NslcdError(fmt.Sprintf("Unknown request action: %#08x", action)))
 	}
-	p.Write(out, p.NSLCD_VERSION)
-	p.Write(out, action)
+	maybePanic(p.Write(out, p.NSLCD_VERSION))
+	maybePanic(p.Write(out, action))
 
 	for result := range ch {
-		p.Write(out, p.NSLCD_RESULT_BEGIN)
-		p.Write(out, result)
+		maybePanic(p.Write(out, p.NSLCD_RESULT_BEGIN))
+		maybePanic(p.Write(out, result))
 	}
-	p.Write(out, p.NSLCD_RESULT_END)
+	maybePanic(p.Write(out, p.NSLCD_RESULT_END))
 }
 EOF