Re: A binary that has PT_LOAD more than 2

[Ryo ONODERA <ryo%tetera.org@localhost>]

Hi,

From: Valery Ushakov <uwe%stderr.spb.ru@localhost>, Date: Tue, 25 Sep 2018 13:13:45 +0300

> On Tue, Sep 25, 2018 at 17:57:19 +0900, Ryo ONODERA wrote:
> 
>> The Go language compiler (pkgsrc/lang/go111) produces
>> three PT_LOAD in a ELF executable.
>> And I found that LLD linker from LLVM also produces three PT_LOAD.
>> 
>> Our ldd(8) command cannot accept three PT_LOAD now.
>> Can we accept three or more PT_LOAD in our ldd(8)?
>> 
>> Are there any other issues to be discussed to support three PT_LOAD
>> binaries?
> 
> Define "our"?
> 
> libexec/ld.elf_so/headers.c:
> 
>  revision 1.62
>  date: 2017-06-23 18:29:21 +0300;  author: joerg;  state: Exp;  lines: +11 -12;  commitid: 9duF2Q9DPoICLvWz;
>  branches:  1.62.4;
>  Remove old assert that only two segments exist. The rest of the code has
>  been changed to cope with more and at least Go actively creates them.
>  Adjust the mapping size computation to use the maximum and not depend on
>  PT_LOAD segments to be in order.
> 
> and this is in current and -8.
> 
> http://gnats.netbsd.org/16983

Thanks for your pointer.
I understand that executing executables that have PT_LOAD more than 2
is valid for NetBSD 8 and current.
It is very good news for me.

However, ldd(8) uses _rtld_map_object() in
src/libexec/ld.elf_so/map_object.c file.
It has the following condition.

        if (nsegs != 2) {
                _rtld_error("%s: wrong number of segments (%d != 2)", path,
                    nsegs);
                goto bad;
        }

This part can be removed safely?

> -uwe

Thank you.

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Ryo ONODERA // ryo%tetera.org@localhost
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