Determine FreeBSD version of binary

[Erik Osterholm]

On Thu, Nov 08, 2007 at 03:47:54PM -0600, Dan Nelson wrote:
> In the last episode (Nov 08), John Smith said:
> > On Nov 8, 2007 6:59 PM, Yuri Pankov <yuri.pankov at gmail.com> wrote:
> > > May be not entirely correct, but close:
> > >
> > > ldd binary | grep libc.so
> > 
> > Yes, that helps somewhat. At least I now know that it's FreeBSD 4.x.
> > And before I again forget something I forgot to mention earlier on: I
> > also have a file called 'kernel'. Could that somehow give somewhat
> > more detailed information about exactly which 4.x kernel it is, and
> > if so, how would I go about doing that ?
> 
> Run "strings /kernel | tail" on it.
> 
> There's also a better way to determine the FreeBSD version an
> executable was built for.  As long as you didn't build world with -O2,
> the "file" command can print it.  Note that you will need to run a 5.x
> or newer version of file, since even though 4.x puts the version in
> each binary, its file command doesn't print it.
> 
> $ file /bin/ls
> /bin/ls: ELF 32-bit LSB executable, Intel 80386, version 1 (FreeBSD), for FreeBSD 7.0 (700052), dynamically linked (uses shared libs), FreeBSD-style, stripped
> $ file /mnt/oldsystem/bin/ls
> /mnt/oldsystem/bin/ls: ELF 32-bit LSB executable, Intel 80386, version 1, for FreeBSD 4.2, statically linked, stripped
> 
> If you like building with -O2, apply the patch in PR 101590.

Interesting.  Does 6.2/amd64 build with -O2 by default?

$ file /bin/ls
/bin/ls: ELF 64-bit LSB executable, AMD x86-64, version 1 (FreeBSD),
dynamically linked (uses shared libs), stripped


This was after a buildworld with no special options added, and nothing
affecting the kernel in make.conf.

Erik