Re: [opensuse] help please - message log and wifi link loss - what does this mean?

----- Original Message ----- From: "John Andersen" To: "Sloan" Cc: Sent: Monday, May 05, 2008 5:42 PM Subject: Re: [opensuse] help please - message log and wifi link loss - what does this mean?

On Mon, May 5, 2008 at 2:33 PM, Sloan wrote:

...

John Andersen wrote:

...

Sighup ("signal heads up" is how I remember this) is sent to the logger that the name of the host has changed.

Close, but no cigar. HUP means "hangup" as when a session is ended (revealing AT&T roots)

Joe

Perhaps historically, but not with regard to daemons in linux.

In that context, specifically in this case with regard to the logging daemon, it is as Sam and I mentioned, a signal to the daemon to re-initialize.

It doesn't matter what a given program does in response to a given signal. The signal is called "hangup" simple as that. It's not something that's "historical" and no longer used that way or anything like that. Any program may react to any trappable signal in any way it wants, including not reacting at all. Some daemons use the hangup signal to re-read their config and/or reinit their whole runtime, and do so on any unix and in some cases have done so since before Linux even existed. There was nothing to correct about Joes statement. Not even slightly. But the implications in your statement are in fact incorrect. Those daemons don't behave that way just on Linux, nor just today vs "historically", and regardless which daemons behave that way and where and when, that still doesn't change the name, nominal meaning, or most common and expected function, in any of the countless, COUNTLESS, binaries extant besides the few daemons that happen to have special behaviour, of the HUP signal. If you think it's confusing that the hangup signal doesn't cause certain special case daemons to "hang up", then maybe you need a better grasp of what init actually does, paying special attention to it's job of _respawinging_ things that it launches, including itself. In some sense, and indeed in the past it was actually implimented just that way, the daemon does hang up, and init immediately respawns it, which from the outside sort of looks like it never stopped running but just re-read it's config. And then at some point the daemon was updated to do what it looks like it's doing, merely update it's state without actually dying and being respawned by init. And init itself is the ultimate special case that does the same thing. So because this one uber special case, init, and very few others, behave in that special way, you propose to teach someone who doesn't know any better that HUP really shouldn't be called or thought of as "hangup", disregarding the fact that every other binary that even catches the signal (which is most of them) does treat a hangup as a hangup or the closest reasonable approximation for whatever context the binary runs in? Um, No. -- Brian K. White brian@aljex.com http://www.myspace.com/KEYofR +++++[>+++[>+++++>+++++++<<-]<-]>>+.>.+++++.+++++++.-.[>+<---]>++. filePro BBx Linux SCO FreeBSD #callahans Satriani Filk! -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org