[uml-devel] Trivial Patch - SIGHUP simulates ctrl-alt-del

[Nick 'S. M. <sh...@zo...>]

G'day Jeff & list,

	I've been playing with virtual networks of UML hosts, and
one thing that's been annoying me is that it's difficult to shut
the network down cleanly. Here's a patch which catches a SIGHUP
to the tracing thread and calls the kernel ctrl_alt_del() procedure.

	If I'm doing this a totally bone-headed way, I'm sure
you'll let me know ... hey, I said it was trivial!

-----sharks

-----8<-----cut here-----8<-----
Based on 2.4.16-2

diff -c trap_kern.orig.c trap_kern.c
*** trap_kern.orig.c	Thu Feb 21 17:40:46 2002
--- trap_kern.c	Thu Feb 21 17:42:24 2002
***************
*** 274,279 ****
--- 274,286 ----
  	init_proxy(debugger_pid, 0, 0);
  }
  
+ void signal_hup(int sig)
+ {
+ 	printk(KERN_ERR "Tracing thread caught SIGHUP: simulating ctrl-alt-del\n");
+ 	/* do I have to do anything clever here? */
+ 	ctrl_alt_del();
+ }
+ 
  int init_ptrace_proxy(int idle_pid, int startup, int stop)
  {
  	int pid, status;

diff -c trap_user.orig.c trap_user.c
*** trap_user.orig.c	Thu Feb 21 17:40:34 2002
--- trap_user.c	Thu Feb 21 17:46:30 2002
***************
*** 114,119 ****
--- 114,120 ----
  extern int io_nsignals, io_count, intr_count;
  
  extern void signal_usr1(int sig);
+ extern void signal_hup(int sig);
  
  int tracing_pid = -1;
  
***************
*** 129,134 ****
--- 130,136 ----
  	calc_sigframe_size();
  	signal(SIGSEGV, signal_segv);
  	signal(SIGUSR1, signal_usr1);
+ 	signal(SIGHUP, signal_hup);
  	signal(SIGPIPE, SIG_IGN);
  	tracing_pid = getpid();
  	printk("tracing thread pid = %d\n", tracing_pid);
-----8<-----cut here-----8<-----

-- 
Nick 'Sharkey' Moore			<Nic...@en...>
Research Fellow, CTIE			Tel: +61 3 9905 3707
Monash University,  Australia		Fax: +61 3 9905 5358