Re: Does Cygwin setup modify dlls?

[Marco Atzeri <marco.atzeri@gmail.com>]

On 22/09/2017 16:11, Eliot Moss wrote:
> On 9/22/2017 10:00 AM, Joachim Eibl wrote:
>> Hi,
>> In our project we like the Cygwin-Setup tool so much that we use it 
>> for our own files too.
>> Adding our archives to our setup.ini was easy enough and almost 
>> everything worked as expected.
>> But then a certain tool didn't work and we found that dll-files that 
>> were unpacked by the Cygwin-installer didn't match the files in the 
>> archive.
>> The problem seems to be dll-specific. Other filetypes are not modified.

> 
> Cygwin's rebasing of DLLs does modify the files (slightly).
> Others can probably detail the exact nature of what changes,
> and perhaps the comparison tool can be refined to ignore that
> as a difference.

the change is on ImageBase address

$ objdump -x /usr/bin/cygglpk-40.dll |grep ImageBase
ImageBase               00000003e1710000

  $ rebase -si |grep  /usr/bin/cygglpk-40.dll
/usr/bin/cygglpk-40.dll 
                                       base 0x0003e1710000 size 0x000ec000

To perform a proper fork all the dlls should be loaded
at not colliding address

This activity is performed by the script
/etc/postinstall/0p_000_autorebase.dash

after the files installation.


> Regards - Eliot Moss

Regards
Marco


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