From b1154ddc4c5852a310b55436f9e34e0c93247926 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Paul=20H=C3=A4nsch?= <paul@plutz.net>
Date: Mon, 2 Jul 2018 15:15:26 +0200
Subject: [PATCH] enable connection reuse in builtin web server

---
 cgilite.sh | 51 ++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 36 insertions(+), 15 deletions(-)

diff --git a/cgilite.sh b/cgilite.sh
index cac905f..4686626 100755
--- a/cgilite.sh
+++ b/cgilite.sh
@@ -24,6 +24,7 @@ setopt -o OCTAL_ZEROES 2>&-
 
 BR="$(printf '\n')"
 CR="$(printf '\r')"
+cgilite_timeout=2
 
 HEADER(){
   # Read value of header line. Use this instead of
@@ -52,22 +53,42 @@ HEX_DECODE(){
 if [ -z "$REQUEST_METHOD" -a -z "$SERVER_PROTOCOL" ]; then
   # no webserver variables means we are running via inetd / ncat
   # so use builtin web server
-  REMOTE_ADDR="${TCPREMOTEIP:-$NCAT_REMOTE_ADDR}"
-  SERVER_NAME="${TCPLOCALIP:-$NCAT_LOCAL_ADDR}"
-  SERVER_PORT="${TCPLOCALPORT:-$NCAT_LOCAL_PORT}"
 
-  read REQUEST_METHOD REQUEST_URI SERVER_PROTOCOL
-  PATH_INFO="$(HEX_DECODE "${REQUEST_URI%\?*}")"
-  QUERY_STRING="${REQUEST_URI#*\?}"
-  cgilite_headers="$(sed -u '/^\r\?$/q')"
-
-  HTTP_CONTENT_LENGTH="$(HEADER Content-Length |grep -xE '[0-9]+')"
-
-  export REMOTE_ADDR SERVER_NAME SERVER_PORT REQUEST_METHOD REQUEST_URI SERVER_PROTOCOL \
-         PATH_INFO QUERY_STRING HTTP_CONTENT_LENGTH
-
-  . "$0" |sed '1{s;^Status: ;HTTP/1.0 ;; t; s;^;HTTP/1.0 200 OK\r\n;;}'
-  exit $?
+  # Use env from inetd as webserver variables
+  REMOTE_ADDR="${TCPREMOTEIP}"
+  SERVER_NAME="${TCPLOCALIP}"
+  SERVER_PORT="${TCPLOCALPORT}"
+
+  # Wait 2 seconds for request or kill connection through watchdog.
+  # Once Request is received the watchdog will be suspended (killed).
+  # At the end of the loop the watchdog will be restarted to enable
+  # timeout for the subsequent request.
+
+  (sleep $cgilite_timeout && kill $$) & cgilite_watchdog=$!
+  while read REQUEST_METHOD REQUEST_URI SERVER_PROTOCOL; do
+    kill $cgilite_watchdog
+    PATH_INFO="$(HEX_DECODE "${REQUEST_URI%\?*}")"
+    QUERY_STRING="${REQUEST_URI#*\?}"
+    cgilite_headers="$(sed -u '/^\r\?$/q')"
+
+    HTTP_CONTENT_LENGTH="$(HEADER Content-Length |grep -xE '[0-9]+')"
+
+    export REMOTE_ADDR SERVER_NAME SERVER_PORT REQUEST_METHOD REQUEST_URI SERVER_PROTOCOL \
+           PATH_INFO QUERY_STRING HTTP_CONTENT_LENGTH
+
+    # Try to serve multiple requests, provided that script serves a
+    # Content-Length header.
+    # Without Content-Length header, connection will terminate after
+    # script.
+
+    . "$0" |sed '1{s;^Status: ;HTTP/1.1 ;; t; s;^;HTTP/1.1 200 OK\r\n;;}' \
+    | while read -r l; do case $l in
+      Content-Length:*) printf '%s\n' "$l"; cat;;
+      $CR) printf 'Connection: close\r\n\r\n'; cat; exit 1;;
+      *) printf '%s\n' "$l";;
+    esac; done || exit 0;
+    (sleep $cgilite_timeout && kill $$) & cgilite_watchdog=$!
+  done
 fi
 
 if [ "$REQUEST_METHOD" = POST -a "${HTTP_CONTENT_LENGTH:=${CONTENT_LENGTH:=0}}" -gt 0 ]; then
-- 
2.39.2