Re: [PATCH 1/2] selftests/pstore: add pstore test script for pre-reboot

[Hiraku Toyooka]

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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