From 3e4e8795c192882e1ede36f6749be80a3a7f74d9 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Mon, 15 Aug 2022 21:21:30 +0100
Subject: [PATCH] prefork-interp: Perl: new protocol, wip

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 perl/Prefork.pm | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/perl/Prefork.pm b/perl/Prefork.pm
index bb39265..10c7ec1 100644
--- a/perl/Prefork.pm
+++ b/perl/Prefork.pm
@@ -36,6 +36,10 @@ sub server_quit ($) {
 
 # Returns in the executor process
 sub become_monitor () {
+  close LISTEN;
+  eval { protocol_exchange(); 1; }
+    or fail_log("protocol exchange failed: $@");
+
   my $child = fork // fail_log("fork executor: $!");
   if (!$child) {
     #---- executor ----
@@ -43,6 +47,7 @@ sub become_monitor () {
     open ::STDOUT, ">& $call_fds[1]" or fail_log("dup for fd1");
     open ::STDERR, ">& $call_fds[2]" or fail_log("dup for fd2");
     close_call_fds();
+    $! = 0;
     return;
   }
 
@@ -54,16 +59,8 @@ sub become_monitor () {
   _exit(0);
 }
 
-sub forked_monitor () {
-  close LISTEN;
-  eval { protocol_exchange(); 1; }
-    or fail_log("protocol exchange failed: $@");
-  return become_monitor();
-}
-
 sub close_call_fds () {
   foreach (@call_fds) {
-    next if $_ <= 2;
     POSIX::close($_);
   }
   close CALL;
@@ -93,7 +90,8 @@ sub protocol_read_fail ($) {
 }
 
 sub protocol_exchange () {
-  protocol_write("\n");
+  my $greeting = "PFI\n\0\0\0\0";
+  protocol_write($greeting);
 
   @call_fds = map {
     my $r;
@@ -223,7 +221,7 @@ sub initialisation_complete {
 	$child = fork // fail_log("fork for accepted call failed: $!");
 	if (!$child) {
 	  #---- monitor [1] ----
-	  forked_monitor();
+	  become_monitor();
 	}
 	close(CALL);
 	$errcount = 0;
-- 
2.30.2