+
+/* sleep for a while via select */
+void u_sleep(int usec)
+{
+ struct timeval tv;
+
+ tv.tv_sec = 0;
+ tv.tv_usec = usec;
+ select(0, NULL, NULL, NULL, &tv);
+}
+
+
+static pid_t all_pids[10];
+static int num_pids;
+
+/* fork and record the pid of the child */
+pid_t do_fork(void)
+{
+ pid_t newpid = fork();
+
+ if (newpid) {
+ all_pids[num_pids++] = newpid;
+ }
+ return newpid;
+}
+
+/* kill all children */
+void kill_all(int sig)
+{
+ int i;
+ for (i=0;i<num_pids;i++) {
+ if (all_pids[i] != getpid())
+ kill(all_pids[i], sig);
+ }
+}