> -----Original Message----- > From: Lennart Poettering [mailto:lenn...@poettering.net] > Sent: Thursday, March 17, 2011 10:38 PM > To: Rainer Gerhards > Cc: Michael Biebl; Andrey Borzenkov; systemd- > de...@lists.freedesktop.org > Subject: Re: [systemd-devel] systemd-logger and external syslog daemon > > On Thu, 17.03.11 08:38, Rainer Gerhards (rgerha...@hq.adiscon.com) > wrote: > > > > You mean a new udev/dracut/systemd on an old kernel? The messages > they > > > print would look a bit weird if they are used together with log msg > > > timestamping the way the kernel does it, since the kernel doesn't > > > recognize the prefix. (See Kay's post about this). But besides > these > > > cosmetic issues nothing should really go wrong. > > > > > > (I wonder if we can find a nice way to detect whether the kernel is > new > > > enough for this, so that we could strip the facility automatically > for > > > older ones. Explcitily checking for kernel versions at runtime is > evil > > > though... I can't think of a good way though...) > > > > Wouldn't it work to check if there is a "<PRI>" right at the start of > the > > message? I think that it is actual user data would be extremely > improbable, > > so this should be a good enough indication. That way, we could pull > the PRI > > even without the kernel patch (but, granted, it is kind of an > interface > > change...). > > Hmm? > > The question is how we can detect whether it is safe to write messages > to kmsg with PRI values with more than 3 bits. 2.6.39 and above will be > able > to handle that properly, even if you enable per-line printk kernel > timestamping. On 2.6.38 only 3-bit-PRI values will look good if you use > printk kernel timestamping.
Probably I misunderstood the answer to "what happens on a kernel without that patch if a full PRI is written?". I understood the answer was "the PRI is moved into the message". So "<123>msg" would actually become "<1> [TS] <123>Msg" >From your answer I deduce this understanding is incorrect. So what will then happen on kernels without that patch if printk is provided a message "<123>MSg"? Rainer _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel