Endianness issues with systemd <-> dbus communication

[Martin Vidner]

On Mon, Mar 10, 2014 at 01:55:06PM +0100, Fridrich Strba wrote:
> Hello, good people,
> 
> I am just wondering whether we have some endianness issues when systemd
> is communicating with dbus-daemon. We have timeouts when waiting for
> returns on s390x.
> 
> We detected that the very first handshake of every message from the
> dbus-daemon does not show the correct header type which would be of the
> type SD_BUS_MESSAGE_METHOD_RETURN aka 1 or type
> SD_BUS_MESSAGE_METHOD_ERROR aka 2.

Actually,
    INVALID = 0
    METHOD_CALL = 1
    METHOD_RETURN = 2
    ERROR = 3
    SIGNAL = 4

> We compared the strace on LE systems with that one on s390x and we
> discovered that there is a difference:
> 
> LE:
> msg_iov(1)=[{"l\2\1\1\v\0\0\0\1\0\0\0=\0\0\0\6\1s\0\6\0\0\0", 24}]
> s390x:
> msg_iov(1)=[{"B\4\1\1\0\0\0\n\0\0\0\2\0\0\0\215\1\1o\0\0\0\0\25", 24}]
> 
> On big endian as on s390x the type is 4 which is SD_BUS_MESSAGE_SIGNAL.
> 
> Any idea to help to debug?

Maybe this little tool will make the straces more readable:
https://github.com/mvidner/dbus-dump
-- 
Martin Vidner, Cloud & Systems Management Team
http://en.opensuse.org/User:Mvidner

Kuracke oddeleni v restauraci je jako fekalni oddeleni v bazenu
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 198 bytes
Desc: Digital signature
URL: <http://lists.freedesktop.org/archives/dbus/attachments/20140310/af48a30c/attachment.pgp>