And here is a follow-up patch to reduce possible race conditions
w.r.t. reuse of process PIDs. The patch is against the maint branch.
Regards,
Stefano
From cfa655a2007dd65cf58149efe393ae33947de956 Mon Sep 17 00:00:00 2001
From: Stefano Lattarini <stefano.lattar...@gmail.com>
Date: Mon, 19 Jul 2010 22:34:18 +0200
Subject: [PATCH] Remove a race condition from test cond5.test.
* tests/cond5.test: Do not blindly try to kill the pid of the
backgrounded Automake process after the sleep, since it might
have terminated by itself, and its PID reused by a new and
unrelated process. Instead, rely on a more complex but more
correct combo of wrapper script(s) and temporary file(s).
Necessity of this fix suggested by Ralf Wildenhues.
---
ChangeLog | 10 ++++++++++
tests/cond5.test | 29 +++++++++++++++++++++++------
2 files changed, 33 insertions(+), 6 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 251ff2e..6e30507 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2010-07-19 Stefano Lattarini <stefano.lattar...@gmail.com>
+
+ Remove a race condition from test cond5.test.
+ * tests/cond5.test: Do not blindly try to kill the pid of the
+ backgrounded Automake process after the sleep, since it might
+ have terminated by itself, and its PID reused by a new and
+ unrelated process. Instead, rely on a more complex but more
+ correct combo of wrapper script(s) and temporary file(s).
+ Necessity of this fix suggested by Ralf Wildenhues.
+
2010-07-18 Stefano Lattarini <stefano.lattar...@gmail.com>
Improve and extend test cond5.test.
diff --git a/tests/cond5.test b/tests/cond5.test
index 84afdd0..37ceaed 100755
--- a/tests/cond5.test
+++ b/tests/cond5.test
@@ -44,25 +44,42 @@ END
# The bug is that automake hangs. So we give it an appropriate grace
# time, then kill it if necessary.
-$ACLOCAL
-$AUTOMAKE 2>stderr &
+# We use a hacky wrapper script to avoid (or reduce to a really low
+# minimum) race conditions w.r.t. process PID.
+
+cat > no-race.sh <<'END'
+#!/bin/sh
+"$@" 2>stderr &
pid=$!
+echo $pid > prog-not-finished
+wait $pid
+rc=$?
+rm -f prog-not-finished
+echo $rc > rc
+exit $rc
+END
+
+$ACLOCAL
+: > prog-not-finished # to be sure it will truly be there from the start
+$SHELL -x ./no-race.sh $AUTOMAKE &
# Make at most 30 tries, one every 10 seconds (= 300 seconds = 5 min).
try=1
while test $try -le 30; do
- if kill -0 $pid; then
- : process $pid is still alive, wait and retry
+ if test -f prog-not-finished; then
+ : process `cat prog-not-finished` is still alive, wait and retry
sleep 10
try=`expr $try + 1`
else
cat stderr >&2
# Automake must fail with a proper error message.
+ test x"1" = x"`cat rc`"
grep 'variable.*OPT_SRC.*recursively defined' stderr
Exit 0
fi
done
# The automake process probably hung. Kill it, and exit with failure.
-echo "$me: automake process $pid hung"
-kill $pid
+# And yes, the repated command substitutions with `cat' are meant.
+echo "$me: automake process `cat prog-not-finished` hung"
+(kill `cat prog-not-finished`) # some shells require this subshell
Exit 1
--
1.7.1
