"I have a need to _really_ know if the interface was properly configured
via ifup so I made busybox's ifupdown pass the return codes through rather
than dropping them on the floor."
"All the functions in ifupdown.c return 1 on success and 0 on failure
(which happens to the opposite of standard practices but whatever).
So it is important for all these functions to not blindly return 1."
"The problem with blindly returning ret, even if it is != 1, is the
callers expect a 0 or 1 and accumulate the return codes. So a function that
makes 3 calls to execute will have a value of 3 accumulated. That value
of 1 (success) was almost always returned even if 1 of the commands in the
command sequence failed. The attached patch fixes the lack of checking
to verify thar result == expected_reult."
Hello,
I have been using busybox for some time now, for an ARM based platform.
I was very pleased when I tried the 1.00preX series, with all the new
utilities and daemons.
I found out that the ifupdown in busybox does not behave exaclty like
the debian version. Then the pre-up script fails, the interface is
getting up. Also when the post-up script fails the return value is
ignored. Actually everything is always run and the return value is
always true. I looked at the original implementation from debian and
fixed the busybox version to do the same. A patch is attached if anyone
is interested.
The attached patch adds "mtu" and "hwaddress" to the inet6 method and
"mtu", "hwaddr" and "pointopoint" to the inet4 method (just like in
the ifupdown part).
Note: "hwaddress" can't be used with the busybox ip applet (this
function isn't implemented in bb ip yet), but it can be of use with
an external "full blown" ip package.
The patch also removes "label" from the loopback configuration,
labels (subinterfaces) aren't used with loopback interfaces.
It further solves a problem in the bootp method, "ifconfig down
%interface%" should be "ifconfig %interface% down" and it's now also
possible to use ip with bootp.
The patch is fully tested with both busybox ip and "stand-alone" ip
and I didn't saw any problems.
The recent changes in ifupdown where all calls to 'ip link set' and
'ip addr set' are swapped give some problems with v4tunnels.
For plain ipv4 and ipv6 interfaces it works correct, other methods
not tried. The patch below change the behaviour back for v4tunnels
only.
Without the patch the following errors are shown:
RTNETLINK answers: Network is down
RTNETLINK answers: No route to host
and the tunnel is not fully brought up
With this patch all works as expected.
this patch fixes run_parts when it's called by ifupdown. 1) argv has to be a
NULL terminated char* array, not just a string. 2) run_parts now explicitly
sets the environment. this environment is populated from the
/etc/network/interfaces config file and is needed by the scripts in
/etc/network/if-pre-up.d/. when run-parts is called from the command line the
environment is taken from the current process.
Vladimir Oleynik then wrote:
You can simplify this if use:
+ bb_xasprintf(&buf[0], "/etc/network/if-%s.d", opt);
+ buf[1] = NULL;
+
+ run_parts(&buf, 2, environ);
+ free(buf[0]);
--w
vodz
Erik, et al.
The attached patch makes the following changes to networking/ifupdown.c:
(1) It swaps all calls to 'ip link set' and 'ip addr set'. This solves
two problems:
(a) Calling 'ip link set <dev> up' before assigning an address
generates an error message, and
(b) Under User Mode Linux, running in with ethernet interfaces
in daemon mode, the MAC address for an interface is selected
based on the IP address assigned to that interface. If the
interface is brought up before being assigned an IP address,
it gets a null MAC.
(2) It further cleans up run_mapping().
This patch is against ifupdown.c revision 1.25.
-- Lars
