RFR: JDK-8227021: VM fails if any sun.boot.library.path paths are longer than JVM_MAXPATHLEN

[David Holmes]

On 2/07/2019 7:44 pm, Adam Farley8 wrote:
> Hi David,
> 
> Thanks for your thoughts.
> 
> The user should absolutely have immediate feedback, yes, and I agree
> that "skipping" paths could lead to us loading the wrong library.
> 
> Perhaps a compromise? We fire off a stderr warning if any of the paths
> are too long (without killing the VM), we ignore any path *after*
> (and including) the first too-long path, and we kill the VM if the
> first path is too long.

My first though is why be so elaborate and not just fail immediately:

Error occurred during initialization of VM
One or more sun.boot.library.path elements is too long for this system.
---

? But AFAICS we don't do any sanity checking of the those paths so this 
would have an impact on startup.

I can't locate where we would detect the too-long path element, is it in 
hostpot or JDK code?

Thanks,
David
-----

> Warning message example:
> 
> ----
> Warning: One or more sun.boot.library.path paths were too long
> for this system, and it (along with all subsequent paths) have been
> ignored.
> ----
> 
> Another addition could be to check the path lengths for the property
> sooner, thus aborting the VM faster if the default path is too long.
> 
> Assuming we posit that the VM will always need to load libraries.
> 
> Best Regards
> 
> Adam Farley
> IBM Runtimes
> 
> 
> David Holmes <david.holmes at oracle.com> wrote on 01/07/2019 22:10:45:
> 
>> From: David Holmes <david.holmes at oracle.com>
>> To: Adam Farley8 <adam.farley at uk.ibm.com>,  hotspot-dev at openjdk.java.net
>> Date: 01/07/2019 22:12
>> Subject: Re: RFR: JDK-8227021:  VM fails if any sun.boot.library.path
>> paths are longer than JVM_MAXPATHLEN
>> 
>> Hi Adam,
>> 
>> On 1/07/2019 10:27 pm, Adam Farley8 wrote:
>> > Hi All,
>> > 
>> > The title say it all.
>> > 
>> > If you pass in a value for sun.boot.library.path consisting
>> > of one or more paths that are too long, then the vm will
>> > fail to start because it can't load one of the libraries it
>> > needs (the zip library), despite the fact that the VM
>> > automatically prepends the default library path to the
>> > sun.boot.library.path property, using the correct separator
>> > to divide it from the user-specified path.
>> > 
>> > So we've got the right path, in the right place, at the
>> > right time, we just can't *use* it.
>> > 
>> > I've fixed this by changing the relevant os.cpp code to
>> > ignore paths that are too long, and to attempt to locate
>> > the needed library on the other paths (if any are valid).
>> 
>> As I just added to the bug report I have a different view of "correct"
>> here. If you just ignore the long path and keep processing other short
>> paths you may find the wrong library. There is a user error here and
>> that error should be reported ASAP and in a way that leads to failure
>> ASAP. Perhaps we should be more aggressive in aborting the VM when  this
>> is detected?
>> 
>> David
>> -----
>> 
>> > I've also added functionality to handle the edge case of
>> > paths that are neeeeeeearly too long, only for a
>> > sub-path (or file name) to push us over the limit *after*
>> > the split_path function is done assessing the path length.
>> > 
>> > I've also changed the code we're overriding, on the assumption
>> > that someone's still using it somewhere.
>> > 
>> > Bug: https://urldefense.proofpoint.com/v2/url?
>> u=https-3A__bugs.openjdk.java.net_browse_JDK-2D8227021&d=DwICaQ&c=jf_iaSHvJObTbx-
>> siA1ZOg&r=P5m8KWUXJf-
>> CeVJc0hDGD9AQ2LkcXDC0PMV9ntVw5Ho&m=cSTGBGkEsu5yl0haJ6it9egPSgixg7mRei6lBDB5Y3k&s=xZzQCnv68xd9hJyyK1obSim38eWSRmLPfuR__9ddZWg&e=
>> > Webrev: https://urldefense.proofpoint.com/v2/url?
>> u=http-3A__cr.openjdk.java.net_-7Eafarley_8227021_webrev_&d=DwICaQ&c=jf_iaSHvJObTbx-
>> siA1ZOg&r=P5m8KWUXJf-
>> CeVJc0hDGD9AQ2LkcXDC0PMV9ntVw5Ho&m=cSTGBGkEsu5yl0haJ6it9egPSgixg7mRei6lBDB5Y3k&s=-
>> hKU0zUd_0LDT08wTilexgI54EeSgt8xUk97i6V63Bk&e= 
>> > 
>> > Thoughts and impressions welcome.
>> > 
>> > Best Regards
>> > 
>> > Adam Farley
>> > IBM Runtimes
>> > 
>> > Unless stated otherwise above:
>> > IBM United Kingdom Limited - Registered in England and Wales  with number
>> > 741598.
>> > Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire  PO6 3AU
>> > 
>> 
> 
> Unless stated otherwise above:
> IBM United Kingdom Limited - Registered in England and Wales with number 
> 741598.
> Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU