[RFC] make bb_[p]error_msgXXXX() functions able to direct output to syslog

[Denis Vlasenko]

Hi,

I worked on zcip (http://bugs.busybox.net/view.php?id=1005)
and in the process I fixed inconsistent use of syslog and bb_[p]error
functions.

But it looks ugly:

+       if (FOREGROUND)
+               bb_perror_msg("%s %s, %s",
+                       arg, intf, why);
+       else
+               syslog(LOG_ERR, "%s %s, %s: %s",
+                       arg, intf, why, strerror(errno));

Worse. If you have a xfunc(), it will not direct its output
to syslog, and I should use ordinary func() instead.

I do not want to do it. It defeats the purpose of xfunc().

The solution which seems ok to me is to make bb_[p]error
syslog aware. That is, we need a global flag variable which
says "direct all bb_[p]error output to syslog (because
we are daemonized and there is no usable stdout/err)"

Minor problem is how to select syslog level, but it isn't
that serious.

Any objections?
--
vda