Add a section on dealing with seg-faults in ppp.

svn path=/head/; revision=2369

FAQ/network.sgml

@@ -1,4 +1,4 @@
-<!-- $Id: network.sgml,v 1.4 1997-12-15 23:38:10 brian Exp $ -->
+<!-- $Id: network.sgml,v 1.5 1998-01-17 14:12:59 brian Exp $ -->
 <!-- The FreeBSD Documentation Project -->
 
   <sect>
@@ -568,6 +568,57 @@ default            10.0.0.2           UGSc        0        0      tun0
           ATDT1234567
         </verb>
 
+      <sect2>
+        <heading>Ppp gets a seg-fault, but I see no <tt/ppp.core/ file</heading>
+
+        <p>Ppp (or any other program for that matter) should never
+        dump core.  Because ppp runs with an effective user id of 0,
+        the operating system will not write ppps core image to disk
+        before terminating it.  If, however ppp <bf/is/ actually
+        termating due to a segmentation violation or some other
+        signal that normally causes core to be dumped, <bf/and/ you're
+        sure you're using the latest version (see the start of this
+        section), then you should do the following:
+
+        <verb>
+          $ tar xfz ppp-*.src.tar.gz
+          $ cd ppp*/ppp
+          $ echo STRIP= >>Makefile
+          $ echo CFLAGS+=-g >>Makefile
+          $ make clean all
+          $ su
+          # make install
+          # chmod 555 /usr/sbin/ppp
+        </verb>
+
+        <p>You will now have a debuggable version of ppp installed.  You
+        will have to be root to run ppp as all of its privileges have
+        been revoked.  When you start ppp, take a careful note of what
+        your current directory was at the time.
+
+        <p>Now, if and when ppp receives the segmentation violation, it
+        will dump a core file called ppp.core.  You should then do the
+        following:
+
+        <verb>
+          $ su
+          # gdb /usr/sbin/ppp ppp.core
+          (gdb) bt
+          .....
+          (gdb) f 0
+          .....
+          (gdb) i args
+          .....
+          (gdb) l
+          .....
+        </verb>
+
+        <p>All of this information should be given alongside your
+        question, making it possible to diagnose the problem.
+        <p>If you're familiar with gdb, you may wish to find out some
+        other bits and pieces such as what actually caused the dump and
+        the addresses & values of the relevant variables.
+
       <sect2>
         <heading>None of this helps - I'm desperate !</heading>