workings-book/entries/2015-01-27.md

Tuesday, January 27

what version of what linux distribution is this?

Some luck may be had with one or more of:

root@beaglebone:~# uname -a
Linux beaglebone 3.8.13-bone47 #1 SMP Fri Apr 11 01:36:09 UTC 2014 armv7l GNU/Linux

root@beaglebone:~# lsb_release -a
No LSB modules are available.
Distributor ID:	Debian
Description:	Debian GNU/Linux 7.8 (wheezy)
Release:	7.8
Codename:	wheezy

root@beaglebone:~# cat /etc/debian_version 
7.8

root@beaglebone:~# cat /etc/dogtag
BeagleBoard.org BeagleBone Debian Image 2014-04-23

root@beaglebone:~# cat /etc/os-release 
PRETTY_NAME="Debian GNU/Linux 7 (wheezy)"
NAME="Debian GNU/Linux"
VERSION_ID="7"
VERSION="7 (wheezy)"
ID=debian
ANSI_COLOR="1;31"
HOME_URL="http://www.debian.org/"
SUPPORT_URL="http://www.debian.org/support/"
BUG_REPORT_URL="http://bugs.debian.org/"

armhf

Is it armhf or armel?:

During diagnosis, the question becomes, how can I determine whether my Linux distribution is based on armel or armhf? Turns out this is not as straightforward as one might think. Aside from experience and anecdotal evidence, one possible way to ascertain whether you're running on armel or armhf is to run the following obscure command:

$ readelf -A /proc/self/exe | grep Tag_ABI_VFP_args

If the Tag_ABI_VFP_args tag is found, then you're running on an armhf system. If nothing is returned, then it's armel. To show you an example, here's what happens on a Raspberry Pi running the Raspbian distribution:

pi@raspberrypi:~$ readelf -A /proc/self/exe | grep Tag_ABI_VFP_args
Tag_ABI_VFP_args: VFP registers

This indicates an armhf distro, which in fact is what Raspbian is. On the original, soft-float Debian Wheezy distribution, here's what happens:

pi@raspberrypi:~$ readelf -A /proc/self/exe | grep Tag_ABI_VFP_args

Nothing returned indicates that this is indeed armel.

On a recent-ish Beaglebone Black:

root@beaglebone:~# readelf -A /proc/self/exe | grep Tag_ABI_VFP_args
  Tag_ABI_VFP_args: VFP registers