Re: [gentoo-portage-dev] [PATCH] Generate soname dependency metadata (282639)

[Anthony G. Basile]

On 01/29/15 21:02, Zac Medico wrote:
>>> +#    hppa_{32,64}
>>> +#    ia_{32,64}
>>> +#    m68k_{32,64}
>>> +#    mips_{eabi32,eabi64,n32,n64,o32,o64}
>>> +#    ppc_{32,64}
>>> +#    s390_{32,64}
>>> +#    sh_{32,64}
>>> +#    sparc_{32,64}
>>> +#    x86_{32,64,x32}
>>> +#
>>> +# NOTES:
>>> +#
>>> +# * The ABIs referenced by some of the above *_32 and *_64 categories
>>> +#   may be imaginary, but they are listed anyway, since the goal is to
>>> +#   establish a naming convention that is as consistent and uniform as
>>> +#   possible.
>>> +#
>>> +# * The Elf header's e_ident[EI_OSABI] byte is completely ignored,
>>> +#   since OS-independence is one of the goals. The assumption is that,
>>> +#   for given installation, we are only interested in tracking multilib
>>> +#   ABIs for a single OS.
>>
>> If you run readelf -h on (say) bash in any of our stage3's tarballs you
>> always get "OS/ABI: UNIX - System V" irrespective of arch and abi.  I
>> don't know what you would get on BSD, but the field is totally
>> irrelevant for our purposes despite the name.  As far as I can tell, it
>> is totally invariant across arches and abis.
>>
>> You can even unpack the the stage3's on an amd64 host and run readelf
>> form the host on the chroot target and you'll get the elf header, so you
>> don't need access to native hardware.
>>
>> The comment suggests that there might be some interesting information
>> there, but there isn't.  Maybe I'm just reading too much into it.
>
> Well, a quick google search seems to indicate that FreeBSD uses
> EI_OSABI. I was specifically thinking about FreeBSD when I wrote that
> comment, because I was aware that Gentoo/FBSD was using ELF, and I just
> assumed that they would have a different EI_OSABI than Linux.

Even there you'll get "UNIX - System V".  I don't have a freebsd system 
ready to go, but here's what i get from my openbsd system:

# uname -a
OpenBSD obi.dis 5.6 GENERIC.MP#333 amd64
# readelf -h /bin/sh
ELF Header:
   Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
   Class:                             ELF64
   Data:                              2's complement, little endian
   Version:                           1 (current)
   OS/ABI:                            UNIX - System V
   ABI Version:                       0
   Type:                              EXEC (Executable file)
   Machine:                           Advanced Micro Devices X86-64
   Version:                           0x1
   Entry point address:               0x400260
   Start of program headers:          64 (bytes into file)
   Start of section headers:          442512 (bytes into file)
   Flags:                             0x0
   Size of this header:               64 (bytes)
   Size of program headers:           56 (bytes)
   Number of program headers:         7
   Size of section headers:           64 (bytes)
   Number of section headers:         17
   Section header string table index: 16


I have *never* seen the OS/ABI be anything different.  That's what 
struck me about your comment.  Anyhow, we're far afield.

I might install freebsd later in a vm just to have one handy and check.

-- 
Anthony G. Basile, Ph. D.
Chair of Information Technology
D'Youville College
Buffalo, NY 14201
[phone]