RFR [XS]: 8224958: add os::dll_load calls to event log

[Thomas Stüfe]

On Tue, Jun 4, 2019 at 2:24 PM Baesken, Matthias <matthias.baesken at sap.com>
wrote:

> Hi Thomas thanks for the input !
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>    - . dlerror() may return NULL
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> Sure I can add this , makes sense to check for NULL !
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> Looks like there are a few other   places   of dlerror usage where a NULL
> check is missing , one example  :
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> jdk/src/jdk.crypto.cryptoki/unix/native/libj2pkcs11/p11_md.c
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> 108        systemErrorMessage = dlerror();
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> 109        exceptionMessage = (char *) malloc(sizeof(char) *
> (strlen(systemErrorMessage) + strlen(libraryNameStr) + 1));
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>    - add the dlerror output to the log (where easily available)
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> My “fear”  was the messages might get a bit too long and eat up too much
> space ,  do you think it is fine ?
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I think they are rather short. They are static strings baked into the libc.
You could manually truncate them via %.xxxs, e.g. to 64 chars with %.64s .
You also could just print to the log, since it will automatically truncate
at 255 or 512 chars (I forgot which).

Cheers, Thomas


> Best regards, Matthias
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> *From:* Thomas Stüfe <thomas.stuefe at gmail.com>
> *Sent:* Dienstag, 4. Juni 2019 14:14
> *To:* Baesken, Matthias <matthias.baesken at sap.com>
> *Cc:* hotspot-dev at openjdk.java.net
> *Subject:* Re: RFR [XS]: 8224958: add os::dll_load calls to event log
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> Hi Matthias,
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> this is useful. Can you please
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> - add the dlerror output to the log (where easily available)
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> - I see an existing issue on some platforms where the return value of
> dlerror() is copied without null check first. dlerror() may return NULL.
> Can you please add null checks where needed?
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> Thanks!
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> ..Thomas
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> On Tue, Jun 4, 2019 at 2:03 PM Baesken, Matthias <matthias.baesken at sap.com>
> wrote:
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> Hello, please review  the following small  change .
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> The current event log holds the last n events of various interesting
> operations.
> It is printed in the hs_err file and helps to analyze various issues /
> bugs .
> I would like to add shared library loading operations (os::dll_load) to
> the events added by calling Events::log.
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> Bug/webrev :
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> https://bugs.openjdk.java.net/browse/JDK-8224958
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> http://cr.openjdk.java.net/~mbaesken/webrevs/8224958.0/
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> Best regards, Matthias
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>