Hello,

I'm sorry for my late reply.

Mark Salyzyn wrote:
Perfectly match is an issue, since something else might be using pmsg.
For instance, one of the applications that uses this interface
packetizes the messages so they can be picked out from other sources
that do not comply with the header (count, magic number etc). In this
case, should that daemon be active, your content would be ignores, but
your content would also be buried, but can be needled out with grep.

What you should do is grep for your string pattern within some
acceptable regex, and one should be found and no other, and it should
match perfectly. This would prevent another daemon's content from
disrupting your test and causing a false negative.

OK. I think that the following method suit your intention.
By splitting unique test string into TEST_STRING_PATTERN part and UUID
part, we can check both the non-existence of previous content and the
unique match on reboot-comparison run.
I'll include this in v2.

# before crash
TEST_STRING_PATTERN="Testing pstore: uuid="
UUID=`cat /proc/sys/kernel/random/uuid`
echo "$TEST_STRING_PATTERN""$UUID" > /dev/pmsg0
echo "$UUID" > uuid

# after crash
prlog -n "Checking pmsg file properly keeps the content written before crash ... "
nr_matched=`grep -c "$TEST_STRING_PATTERN" pmsg-${backend}-0`
if [ $nr_matched -eq 1 ]; then
    grep -q "$TEST_STRING_PATTERN"`cat uuid` pmsg-${backend}-0
    if [ $? -eq 0 ]; then
        prlog "ok"
    else
        prlog "FAIL"
else
    prlog "FAIL"
fi


Best regards,
Hiraku Toyooka

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