Ticket #3626: netcat-with-option-q.patch

netcat.c

@@ -154 +154 @@
 USHORT o_listen = 0;
 USHORT o_nflag = 0;
 USHORT o_wfile = 0;
+int o_quittimeout = 0;
 USHORT o_random = 0;
 USHORT o_udpmode = 0;
 USHORT o_verbose = 0;
@@ -224 +225 @@
   bail (" punt!");
 }
 
+/* quitaftertimeout:
+   singal handler which quits after user given seconds after close of stdin */
+void quitaftertimeout ()
+{
+  close(netfd);
+  exit(0);
+}
+
 /* timeout and other signal handling cruft */
 void tmtravel ()
 {
@@ -1172 +1181 @@
     } /* select fuckup */
 /* if we have a timeout AND stdin is closed AND we haven't heard anything
    from the net during that time, assume it's dead and close it too. */
+
+/* we need this section of if -q is not given, otherwise we dont quit if we
+   dont receive from net, we quit after timeout given with -q */
+if (o_quittimeout == 0) {
     if (rr == 0) {
     if (! FD_ISSET (0, ding1))
       netretry--;           /* we actually try a coupla times. */
@@ -1182 +1195 @@
       return (0);           /* not an error! */
     }
     } /* select timeout */
+}
 /* xxx: should we check the exception fds too?  The read fds seem to give
    us the right info, and none of the examples I found bothered. */
 
@@ -1215 +1229 @@
     if (rr <= 0) {          /* at end, or fukt, or ... */
       FD_CLR (0, ding1);        /* disable and close stdin */
       close (0);
+      if (o_quittimeout > 0) {
+        if (o_verbose > 1)
+          fprintf (stderr, "STDIN closed, quit after %d seconds\n", o_quittimeout);
+        signal (SIGALRM, quitaftertimeout);
+        alarm (o_quittimeout);
+        // if -q argument is < 0 we dont trigger any signal and we also don't
+        // check for rr == 0 above, hence this is an infinite loop, essentially
+        // waiting forever on fd of net.
+      }
     } else {
       rzleft = rr;
       zp = bigbuf_in;
@@ -1388 +1411 @@
 
 /* If your shitbox doesn't have getopt, step into the nineties already. */
 /* optarg, optind = next-argv-component [i.e. flag arg]; optopt = last-char */
-  while ((x = getopt (argc, argv, "ae:g:G:hi:lno:p:rs:tuvw:z")) != EOF) {
+  while ((x = getopt (argc, argv, "ae:g:G:hi:lno:p:q:rs:tuvw:z")) != EOF) {
 /* Debug (("in go: x now %c, optarg %x optind %d", x, optarg, optind)) */
     switch (x) {
       case 'a':
@@ -1440 +1463 @@
     if (o_lport == 0)
       bail ("invalid local port %s", optarg);
     break;
+        case 'q':
+    o_quittimeout = atoi(optarg); break;
       case 'r':             /* randomize various things */
     o_random++; break;
       case 's':             /* local source address */
@@ -1649 +1674 @@
     -n          numeric-only IP addresses, no DNS\n\
     -o file         hex dump of traffic\n\
     -p port         local port number\n\
+    -q secs         after  EOF on stdin, wait the specified number\n\
+                    of seconds and then quit. If seconds is\n\
+                    negative, wait forever.\n\
     -r          randomize local and remote ports\n\
     -s addr         local source address");
 #ifdef TELNET