[Pharo-project] Cog+linux: external module not found

Schwab,Wilhelm K bschwab at anest.ufl.edu
Mon Jan 9 20:06:12 CET 2012


I think you have the situation very much in reverse.  You are flying off the handle, not me.

Cog deserves better than to ignore feedback from motivated users.  Motivated users deserve better than to be insulted for their efforts to improve it.






________________________________
From: pharo-project-bounces at lists.gforge.inria.fr [pharo-project-bounces at lists.gforge.inria.fr] on behalf of Eliot Miranda [eliot.miranda at gmail.com]
Sent: Monday, January 09, 2012 1:57 PM
To: Pharo-project at lists.gforge.inria.fr
Subject: Re: [Pharo-project] Cog+linux: external module not found

I'm definitely not interested in help from someone who flies off the handle like this.  Plonk.

On Mon, Jan 9, 2012 at 10:55 AM, Schwab,Wilhelm K <bschwab at anest.ufl.edu<mailto:bschwab at anest.ufl.edu>> wrote:
Eliot,

Whining - that's a bit much.  In fact it is TOTALLY unjustified.

Last year, I spent (end to end) months learning how to get away from creating my own hacked vms - that's how I knew about ldconfig's behavior , and have come to appreciate that Canonical got this one right.

Recently, I spent hours running down why Cog fails to find properly installed libraries on a major Linux platform.  I'd say that's "pitching in."  It sure isn't whining!!

Am I certain of all the details of what should happen and why?  No.  Am I the best person to tell the vm to stop looking here/there/everywhere and just use the module name as given?  Certainly not.  I *thought* you might want to do that yourself, so it gets done properly.

I also thought you might appreciate some help in debugging a problem.  Instead you tell me that I am an SOL whiner.  Not good.

Bill



________________________________
From: pharo-project-bounces at lists.gforge.inria.fr<mailto:pharo-project-bounces at lists.gforge.inria.fr> [pharo-project-bounces at lists.gforge.inria.fr<mailto:pharo-project-bounces at lists.gforge.inria.fr>] on behalf of Eliot Miranda [eliot.miranda at gmail.com<mailto:eliot.miranda at gmail.com>]
Sent: Monday, January 09, 2012 1:34 PM

To: Pharo-project at lists.gforge.inria.fr<mailto:Pharo-project at lists.gforge.inria.fr>
Subject: Re: [Pharo-project] Cog+linux: external module not found



On Sat, Jan 7, 2012 at 5:16 PM, David T. Lewis <lewis at mail.msen.com<mailto:lewis at mail.msen.com>> wrote:
On Sun, Jan 08, 2012 at 12:37:59AM +0000, Schwab,Wilhelm K wrote:
> Eliot,
>
> SOL??  Is that really the message we want to send to current and *prospective* users?  Canonical does something that makes sense from a security perspective (one needs root privileges to alter the ldconfig mapping, not to to use it).  All the vm needs to do is request the #moduleName as given, and users of Pharo "SOL" as a result?
>
> Please reconsider.
>
> Bill
>

I think you are taking the response out of context. The actual statement
was "Then you're SOL :)  You'd need to write new support for Ubuntu."

You might take that as a gentle suggestion to expend a bit of effort
on it yourself. After all, it is open source, and Eliot is only one
person. He can't do everything for everybody without a little help
from the rest of us.

quite.  i don't even have an ubuntu VM, let alone the time to work on it.  Bill, instead of whining, pitch in, please.


Dave


>
>
>
> ________________________________
> From: pharo-project-bounces at lists.gforge.inria.fr<mailto:pharo-project-bounces at lists.gforge.inria.fr> [pharo-project-bounces at lists.gforge.inria.fr<mailto:pharo-project-bounces at lists.gforge.inria.fr>] on behalf of Eliot Miranda [eliot.miranda at gmail.com<mailto:eliot.miranda at gmail.com>]
> Sent: Saturday, January 07, 2012 6:38 PM
> To: Pharo-project at lists.gforge.inria.fr<mailto:Pharo-project at lists.gforge.inria.fr>
> Subject: Re: [Pharo-project] Cog+linux: external module not found
>
>
>
> On Sat, Jan 7, 2012 at 8:49 AM, Schwab,Wilhelm K <bschwab at anest.ufl.edu<mailto:bschwab at anest.ufl.edu><mailto:bschwab at anest.ufl.edu<mailto:bschwab at anest.ufl.edu>>> wrote:
> Nick,
>
> Partial success.  After a false start with getting output from strace (my fault), it showed me that the vm was looking a lot in the vm's directory.  A symlink by the same name, allowed it to see the library.  Clearly, this is not a fix, because one should not be forced to make links to any/every library on the system.  However, it *was* nice to see the version string in an inspector :)
>
> Looking at the strace output (relevant parts below), it tries with prepending lib, appending .so, .so.dylib.  It looks in the vm's directory, and in the root directory, not /usr/lib.
>
> It has been almost a year (based on a dated comment) since I last really strained my synapses on the workings of ldconfig.  On my systems, it would tell one to look for the library as follows:
>
>     ldconfig -p | grep Acces
>     libAccesIO-USB.so (libc6) => /usr/lib/libAccesIO-USB.so
>
> #moduleName answers 'libAccesIO-USB.so', and Ian's vm finds it.  My (and I use the term LOOSELY) understanding is that Ubuntu no longer uses LD_LIBRARY_PATH.  dlopen() seems to prefer that one use the names as reported by ldconfig.  The best explanation I have found is that the change was a security measure.
>
> Then you're SOL :)  You'd need to write new support for Ubuntu.
>
>
> How does one get ldconfig to "know" where something lives?  Putting a .so file in /usr/lib (and perhaps other places too) and then running ldconfig as sudo appears to build a cache.  Then ldconfig -p (anyone can run this) will show the map, and one can grep the result to find something specifc, as above.
>
> Putting files in /usr/lib is a pain for things under active development.  A file can live anywhere if one puts a .conf file in /etc/ld.so.confd; the .conf files should contain paths to directories to be searched for .so files - or at least that's how it *appears* to work.  Run ldconfig as sudo to refresh the mapping, and verify with ldconfig - p.
>
> The fix might be as simply as having the cog vm try passing the #moduleName to dlopen().
>
> Nick, thanks for the nudge in a working direction.  I will probably symlink another file and see if a mix of hardware and software will get closer to cooperating with me.
>
> Bill
>





--
best,
Eliot




--
best,
Eliot

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