From c36103d9dfcca11f75a568d5ab9569e28ba35d1e Mon Sep 17 00:00:00 2001
From: Aaron Ball <nullspoon@iohq.net>
Date: Sat, 28 May 2016 11:07:44 -0600
Subject: Put in msg timeout waiting for ping response

Before, occasionally, the server would not respond (usually due to
connection flood when used with a scheduler) with a ping response. This
caused the get_ping function to infinitely loop, very quickly, causing
the cpu to spike and the process to never exit. This commit fixes that
behavior by looping no more than 50 times with an empty response before
exiting.

Also added a "no ping response received" error message to better explain
when exiting with failure in this scenario.
---
 ircmsg.sh | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/ircmsg.sh b/ircmsg.sh
index 754d736..a504466 100755
--- a/ircmsg.sh
+++ b/ircmsg.sh
@@ -24,12 +24,22 @@ portfd=''
 # matching "PING". Retrieves value of that line (without the PING prefix), and
 # returns so the corresponding PONG can be sent.
 #
+# Note: This function will timeout when reading from the server 100 times
+#
 function get_ping {
   local portfd=${1}
+  local emptymax=50
+  local emptycount=0
 
   # get ping
-  while [[ ${ping:0:4} != 'PING' ]]; do
+  while [[ ${emptycount} -lt ${emptymax} ]]; do
     read ping <&${portfd}
+
+    # If first four match PING, break and process
+    [[ ${ping:0:4} == 'PING' ]] && break
+
+    # If response is empty, increment empty counter
+    [[ ${ping} == '' ]] && emptycount=$(($emptycount + 1))
   done
   
   ping=${ping:5}
@@ -87,6 +97,11 @@ function main {
 
   # Respond to the server with its ping value (ping pong)
   ping=$(get_ping ${portfd})
+  if [[ ${ping} == '' ]]; then
+    echo "ERROR: No PING response received. Cannot continue."
+    exit 1
+  fi
+
   echo "PONG ${ping}" >&${portfd}
 
   # Send message to specified channel
-- 
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