Re: Add SOCK_STREAM support for syslog

[Rich Felker <dalias@libc.org>]

On Fri, Nov 10, 2017 at 03:07:49PM +0100, Szabolcs Nagy wrote:
> * Jan Horstmann <J.Horstmann@mittwald.de> [2017-11-10 13:17:31 +0000]:
> > some time ago there was a discussion whether musl-libc's syslog should
> > support SOCK_STREAM as a fall back if SOCK_DGRAM fails like glibc does
> > ( http://www.openwall.com/lists/musl/2015/08/10/1 )
> > Later on a patch was posted to the mailing list: http://www.openwall.com/lists/musl/2017/08/21/3
> > Since we depend on this functionality we have applied this patch and are quiet happy with it.
> > I would like to know whether there are any plans to incorporate this patch into a future release?
> 
> i think you need to explain why you depend on this
> to get consensus on the inclusion of the patch.

Is it mutually exclusive whether /dev/log is listening as SOCK_DGRAM
or SOCK_STREAM? If not, I think there's a race where connecting to
SOCK_DGRAM fails, then syslogd starts listening on both, and the
SOCK_STREAM connect succeeds in the fallback despite there being a
SOCK_DGRAM service available. Adoption of the patch is mainly blocked
on establishing that it does not harm any existing usage. I suspect
and seem to remember (but haven't looked at it lately) that
SOCK_STREAM has some undesirable properties from a standpoint of
logging and that SOCK_DGRAM is what you want if possible.

Rich