Bug#798329: ifconfig: changed output format breaks scripts

[Thorsten Glaser]

On Tue, 8 Sep 2015, Guillem Jover wrote:

> Well, the ifconfig implementation in inetutils provides selectable

Oh, there’s another one? I’ve not looked at that one (yet)…

… but then, I really need something that works even with CentOS,
though it (even in version 6, which is way younger than 2003)
has the same output format as jessie.

> > Finally, I have no intentions on maintaining a fork of net-tools to
> > support the 14 years old output format of ifconfig, so I am closing this
> > as wontfix.
> 
> This is quite reasonable IMO.

Mh okay. I’m using code similar to the following to catch both
the old and new format (some day I’m going to test inetutils’):


export LC_ALL=C PATH=/bin:/sbin:/usr/bin:/usr/sbin
unset LANGUAGE

hn=$(hostname -f || echo $(hostname).invalid.fqdn)
[[ $hn = *.* ]] || hn=$hn.no.fqdn

lladdr=
test -s /etc/tarent/primary.mac && lladdr=$(cat /etc/tarent/primary.mac)
test -n "$lladdr" || lladdr=$(tgetif | \
sed -ne '/^ *ether 
\([0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]\)\(
 .*\)$/s//\1/p' -e '2,$d' -e '/^.* HWaddr 
\([0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]:[0-9a-fA-F][0-9a-fA-F]\)\(
 .*\)$/s//\1/p' | head -n 1)
ipaddr=$(tgetif | sed -n '/^ *inet \(addr:\)*\([0-9.]*\) .*$/s//\2/p')
netconf=$(/sbin/ip a | tr '\n' '~' | sed 's/~ /= /g' | tr '~' '\n' | fgrep -v 
vnet | tr '=' '\n' | sed -ne '/^[0-9]*: 
\([^:@]*\)\(@NONE\)*\([^:]*\):.*$/s//\1\3/p' -e '/inet/s/ scope.*//p' -e '/ 
link/s/ brd.*$//p'
) || netconf=


Maybe this helps others.

bye,
//mirabilos
-- 
tarent solutions GmbH
Rochusstraße 2-4, D-53123 Bonn • http://www.tarent.de/
Tel: +49 228 54881-393 • Fax: +49 228 54881-235
HRB 5168 (AG Bonn) • USt-ID (VAT): DE122264941
Geschäftsführer: Dr. Stefan Barth, Kai Ebenrett, Boris Esser, Alexander Steeg

Bug#798329: ifconfig: changed output format breaks scripts

[Martín Ferrari]

THorsten,

On 08/09/15 10:25, Thorsten Glaser wrote:

> the changed output format of ifconfig breaks scripts parsing it.
[..]
> This particularily breaks both getting the MAC address and
> the/an IP address.

I don't think it is feasible to try and keep the old format, I have
finally updated net-tools to what upstream has been doing in the past 10
years..

Is this breaking a package or just your scripts?

In any case, I think you should be doing this differently. Either using
iproute2 that has a parseable format (although that has changed too), or
direcly parsing files in /proc/net

-- 
Martín Ferrari (Tincho)

Bug#798329: ifconfig: changed output format breaks scripts

[Thorsten Glaser]

Package: net-tools
Version: 1.60+git20150829.73cef8a-1
Severity: important

Hi,

the changed output format of ifconfig breaks scripts parsing it.

Before:

br0   Link encap:Ethernet  HWaddr 90:e2:ba:0c:b8:17  
  inet addr:172.26.3.108  Bcast:172.26.255.255  Mask:255.255.0.0
  inet6 addr: fe80::21b:21ff:fe62:2577/64 Scope:Link
  UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
  RX packets:2351724 errors:0 dropped:2931 overruns:0 frame:0
  TX packets:525699 errors:0 dropped:0 overruns:0 carrier:0
  collisions:0 txqueuelen:0 
  RX bytes:1659213748 (1.5 GiB)  TX bytes:216861337 (206.8 MiB)

After:

br0: flags=4163  mtu 1500
inet 172.26.3.108  netmask 255.255.0.0  broadcast 172.26.255.255
inet6 fe80::21b:21ff:fe62:2577  prefixlen 64  scopeid 0x20
ether 90:e2:ba:0c:b8:17  txqueuelen 0  (Ethernet)
RX packets 2351867  bytes 1659222913 (1.5 GiB)
RX errors 0  dropped 2931  overruns 0  frame 0
TX packets 525708  bytes 216861987 (206.8 MiB)
TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

This particularily breaks both getting the MAC address and
the/an IP address.

-- System Information:
Debian Release: stretch/sid
  APT prefers unreleased
  APT policy: (500, 'unreleased'), (500, 'buildd-unstable'), (500, 'unstable')
Architecture: x32 (x86_64)
Foreign Architectures: i386, amd64

Kernel: Linux 4.1.0-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=C, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/lksh
Init: sysvinit (via /sbin/init)

Versions of packages net-tools depends on:
ii  libc6  2.19-19

net-tools recommends no packages.

net-tools suggests no packages.

-- no debconf information

Bug#798329: ifconfig: changed output format breaks scripts

[Thorsten Glaser]

On Tue, 8 Sep 2015, Martín Ferrari wrote:

> Is this breaking a package or just your scripts?

This is breaking at least two scripts of mine, which is where and why
I noticed this immediately after the dist-upgrade today, but there’ll
be others lurking. Probably none of them packaged, though.

> In any case, I think you should be doing this differently. Either using
> iproute2 that has a parseable format (although that has changed too), or

This won’t work, I did quite the WTF today at iproute2 now, as it
appends “@NONE” to the interface names.

I need reliable, consistent, parsable output across all Debian versions
(and some derivates).

> direcly parsing files in /proc/net

Excuse me, but WTF?

The standard Unix interface for things is stdout of other commands,
as in, filters and pipes. ifconfig is *the* standard utility to get
information about interfaces.

bye,
//mirabilos
-- 
tarent solutions GmbH
Rochusstraße 2-4, D-53123 Bonn • http://www.tarent.de/
Tel: +49 228 54881-393 • Fax: +49 228 54881-235
HRB 5168 (AG Bonn) • USt-ID (VAT): DE122264941
Geschäftsführer: Dr. Stefan Barth, Kai Ebenrett, Boris Esser, Alexander Steeg

Bug#798329: ifconfig: changed output format breaks scripts

[Guillem Jover]

Hi!

On Tue, 2015-09-08 at 12:56:09 +0300, Martín Ferrari wrote:
> On 08/09/15 12:34, Thorsten Glaser wrote:
> > I need reliable, consistent, parsable output across all Debian versions
> > (and some derivates).
> 
> There is no software that currently offers that promise. I understand it
> is annoying, and myself have reported a bug to iproute2 (#726417) for a
> similar situation, but the maintainer also did not want to diverge from
> upstream, so I had to live with that.

Well, the ifconfig implementation in inetutils provides selectable
output formats, which might be close to that promise, but I think
I agree in general that relying on this kind of output is not wise.

> >> direcly parsing files in /proc/net
> > 
> > Excuse me, but WTF?
> > 
> > The standard Unix interface for things is stdout of other commands,
> > as in, filters and pipes. ifconfig is *the* standard utility to get
> > information about interfaces.
> 
> Sorry, but ifconfig output is not standarised by policy or any other
> doc. In fact, it varies wildly in its many implementations. It has been
> deprecated as a means of talking with the network stack in Linux since
> iproute exists, which is a Long Time Ago.

Yes, see the above comment on inetutils' ifconfig selectable output.

> Also, it is not breaking other Debian packages, nor it is
> malfunctioning, so severity can't be more than wishlist.

We might not know yet, I do actually expect this might break some
stuff also parsing output from ifconfig. Perhaps a quick check could
be performed on codesearch.d.n?

> Finally, I have no intentions on maintaining a fork of net-tools to
> support the 14 years old output format of ifconfig, so I am closing this
> as wontfix.

This is quite reasonable IMO.

Thanks,
Guillem

Bug#798329: ifconfig: changed output format breaks scripts

[Martín Ferrari]

severity 798329 wishlist
tags 798329 wontfix
close 798329
thanks

On 08/09/15 12:34, Thorsten Glaser wrote:

> I need reliable, consistent, parsable output across all Debian versions
> (and some derivates).

There is no software that currently offers that promise. I understand it
is annoying, and myself have reported a bug to iproute2 (#726417) for a
similar situation, but the maintainer also did not want to diverge from
upstream, so I had to live with that.

>> direcly parsing files in /proc/net
> 
> Excuse me, but WTF?
> 
> The standard Unix interface for things is stdout of other commands,
> as in, filters and pipes. ifconfig is *the* standard utility to get
> information about interfaces.

Sorry, but ifconfig output is not standarised by policy or any other
doc. In fact, it varies wildly in its many implementations. It has been
deprecated as a means of talking with the network stack in Linux since
iproute exists, which is a Long Time Ago.

Also, it is not breaking other Debian packages, nor it is
malfunctioning, so severity can't be more than wishlist.

Finally, I have no intentions on maintaining a fork of net-tools to
support the 14 years old output format of ifconfig, so I am closing this
as wontfix.

-- 
Martín Ferrari (Tincho)

Bug#798329: ifconfig: changed output format breaks scripts

[Thorsten Glaser]

On Tue, 8 Sep 2015, Martín Ferrari wrote:

> Finally, I have no intentions on maintaining a fork of net-tools to
> support the 14 years old output format of ifconfig, so I am closing this
> as wontfix.

Hmpf. I’ll search for scripts using either ip or ifconfig
and do some hackery to work with either output format then.

Will the current format at least stay?

//mirabilos
-- 
tarent solutions GmbH
Rochusstraße 2-4, D-53123 Bonn • http://www.tarent.de/
Tel: +49 228 54881-393 • Fax: +49 228 54881-235
HRB 5168 (AG Bonn) • USt-ID (VAT): DE122264941
Geschäftsführer: Dr. Stefan Barth, Kai Ebenrett, Boris Esser, Alexander Steeg

Bug#798329: ifconfig: changed output format breaks scripts

[Martín Ferrari]

On 08/09/15 13:44, Thorsten Glaser wrote:

> Will the current format at least stay?

Honestly, I don't know upstream plans, but I don't foresee many more
changes. If I read the git logs correctly, this change dates back to
2003, and the latest upload is just catching up with 14 years of
upstream development with no releases.


-- 
Martín Ferrari (Tincho)