Re: [bug-gawk] [PATCH 2/2] Fix plugin load failure on OS/2

[KO Myung-Hun]

Eli Zaretskii wrote:
>> Date: Thu, 12 Oct 2017 20:49:27 +0900
>> From: KO Myung-Hun <address@hidden>
>> CC: address@hidden
>>
>>>> OS/2 cannot load DLLs whose base name is longer than 8 characters.
>>>> Because of this, libtool limits length of DLL base name up to 8
>>>> characters. In Gawk, limits likewise.
>>>
>>> Isn't it better/cleaner to have an OS/2 wrapper for dlopen, and
>>> truncate the name there?  (And why doesn't dlopen itself do that, if
>>> this is an OS/2 limitation?)
>>>
>>
>> Unfortunately, wrapping dlopen() is not enough. Because gawk checks the
>> existence of extensions with find_source(). This patch is for it.
> 
> Maybe I didn't understand the issue well enough.  Could you please
> elaborate on it?  What exactly is the limitation, which C library
> functions enforce it, and how is libtool related to this?
> 

This limitation is from OS/2 itself. Considering this, libtool generates
a DLL whose base name length is not longer than 8 chars. For example, it
produces filefunc.dll not filefuncs.dll.

As a result, trying to load filefuncs extension with '@load filefuncs'
fails, because there is no filefuncs extension on OS/2.

C library function has no relations with this.

> And what happens if I compile an extension into a DLL whose file name
> has more than 8 characters in its base-name?  Will such a DLL be
> completely unusable on OS/2?
> 

It's possible to produce a DLL whose base name is longer than 8 chars.
However, OS/2 cannot load it. One time, there were efforts to overcome
this problem with kernel patch. It's win32k.sys in Odin project. I know,
it succeeded partially. Unfortunately, however, its development stopped.

>> I have a question. there are any cases calling load_ext() without
>> find_source() ?
> 
> Doesn't look that way, but it's hard to tell.

Ok. I've updated patch.

-- 
KO Myung-Hun

Using Mozilla SeaMonkey 2.7.2
Under OS/2 Warp 4 for Korean with FixPak #15
In VirtualBox v4.1.32 on Intel Core i7-3615QM 2.30GHz with 8GB RAM

Korean OS/2 User Community : http://www.os2.kr/

0002-Fix-plugin-load-failure-on-OS-2.patch
Description: Source code patch