--- busybox-1.6.0/procps/kill.c	2007-06-01 13:48:40.000000000 +0200
+++ src/procps/kill.c	2009-02-06 22:41:46.000000000 +0100
@@ -23,7 +23,6 @@
  * kill %n gets translated into kill ' -<process group>' by shell (note space!)
  * This is needed to avoid collision with kill -9 ... syntax
  */
-
 int kill_main(int argc, char **argv);
 int kill_main(int argc, char **argv)
 {
@@ -100,6 +99,11 @@
 		if (arg[0] != '-') goto do_it_now;
 	}
 
+	if (killall5 && arg[1] == 'o') {
+		/* pid omit list starts here */
+		goto do_it_now;
+	}
+
 	/* -SIG */
 	signo = get_signum(&arg[1]);
 	if (signo < 0) { /* || signo > MAX_SIGNUM ? */
@@ -109,11 +113,17 @@
 	arg = *++argv;
 	argc--;
 
+
 do_it_now:
 
 	if (killall5) {
 		pid_t sid;
 		procps_status_t* p = NULL;
+		int ret = 0;
+
+		/* remaining args should be -o pid [-o pid ...] */
+		if (argc & 1)
+			bb_show_usage();
 
 		/* Now stop all processes */
 		kill(-1, SIGSTOP);
@@ -122,12 +132,47 @@
 		sid = getsid(pid);
 		/* Now kill all processes except our session */
 		while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_SID))) {
-			if (p->sid != sid && p->pid != pid && p->pid != 1)
+			int i, found;
+
+			if (p->sid == (unsigned)sid ||
+			    p->pid == (unsigned)pid ||
+			    p->pid == 1)
+				continue;
+
+			/* check all "-o omitpid" */
+			found = 0;
+			for (i = 0; i < argc - 1; i += 2) {
+				pid_t omit;
+
+				arg = argv[i];
+				if (arg[0] != '-' || arg[1] != 'o') {
+					bb_error_msg("bad option '%s'", arg);
+					ret = 1;
+					goto resume;
+				}
+
+				arg = argv[i + 1];
+				omit = bb_strtoi(arg, NULL, 10);
+				if (errno) {
+					bb_error_msg("bad pid '%s'", arg);
+					ret = 1;
+					goto resume;
+				}
+
+				if (p->pid == omit) {
+					found = 1;
+					break;
+				}
+			}
+
+			/* kill unless found */
+			if (!found)
 				kill(p->pid, signo);
 		}
+resume:
 		/* And let them continue */
 		kill(-1, SIGCONT);
-		return 0;
+		return ret;
 	}
 
 	/* Pid or name is required for kill/killall */