[DTrace-devel] [PATCH 3/4] Test the dtrace provider cleanup mechanism

[Kris Van Hees]

On Fri, May 29, 2020 at 08:10:39PM -0400, eugene.loh at oracle.com wrote:
> From: Eugene Loh <eugene.loh at oracle.com>
> 
> Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
> ---
>  test/unittest/providers/tst.dtrace_cleanup.sh | 43 +++++++++++++++++++
>  1 file changed, 43 insertions(+)
>  create mode 100755 test/unittest/providers/tst.dtrace_cleanup.sh
> 
> diff --git a/test/unittest/providers/tst.dtrace_cleanup.sh b/test/unittest/providers/tst.dtrace_cleanup.sh
> new file mode 100755
> index 00000000..ee4892ff
> --- /dev/null
> +++ b/test/unittest/providers/tst.dtrace_cleanup.sh
> @@ -0,0 +1,43 @@
> +#!/bin/bash
> +#
> +# Oracle Linux DTrace.
> +# Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
> +# Licensed under the Universal Permissive License v 1.0 as shown at
> +# http://oss.oracle.com/licenses/upl.
> +
> +##
> +#
> +# ASSERTION:
> +# The dtrace probes BEGIN and END will create pid-tagged uprobes that
> +# will be cleaned up when the dtrace process exits.
> +#
> +##
> +
> +dtrace=$1
> +UPROBE_EVENTS=/sys/kernel/debug/tracing/uprobe_events
> +
> +$dtrace $dt_flags -n 'BEGIN {trace(1234)} END {trace(4321)}' &

Any reason why you added trace() actions?  I don't think they are needed for
this test.

> +pid=$!
> +
> +sleep 1

This could be a problem in some cases - if the system is bogged down it could
potentially happen that it takes more than a second for probes to get enabled.
A more guaranteed test could redirect the output from the dtrace process to a
file and look for the message that states that the probes have been enabled.

> +BEG0=`grep -c p:dt_${pid}_dtrace/BEGIN $UPROBE_EVENTS`
> +END0=`grep -c p:dt_${pid}_dtrace/END   $UPROBE_EVENTS`
> +
> +kill $pid
> +
> +sleep 1

Perhaps it would be better to wait on $pid, so you know for sure that the
process is gone?  That way you can avoid the arbitrary time limit.

> +BEG1=`grep -c p:dt_${pid}_dtrace/BEGIN $UPROBE_EVENTS`
> +END1=`grep -c p:dt_${pid}_dtrace/END   $UPROBE_EVENTS`
> +
> +if [[ $BEG0 != 1 || \
> +     $END0 != 1 || \
> +     $BEG1 != 0 || \
> +     $END1 != 0 ]]; then
> +	echo "problem"

I would remove this - the "exit 1" already signals that the test fails, as
will the disccrepancy between the actual results and the expected results..

Alternatively you could use the expected results file feature of the testsuite
engine, but I personally do prefer your version of testing the outcome in the
test itself.

> +	echo "actual: $BEG0 $END0 $BEG1 $END1"
> +	echo "expect: 1 1 0 0"
> +	exit 1
> +fi
> +
> +exit 0
> +
> -- 
> 2.18.2
> 
> 
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