Summary: Make timeouts work with glibc 2.x.
Contributor: Joe Pepin <jdp@ll.mit.edu>

Index: netcat-1.10/netcat.c
===================================================================
--- netcat-1.10.orig/netcat.c	2006-03-24 12:26:34.000000000 -0500
+++ netcat-1.10/netcat.c	2006-03-24 12:26:36.000000000 -0500
@@ -59,6 +59,14 @@
 #define RAND rand
 #endif /* HAVE_RANDOM */
 
+/* #define POSIX_SETJMP		/* If you want timeouts to work under the */
+				/* posixly correct, yet non-standard glibc-2.x*/
+				/* then define this- you may also need it for */
+				/* IRIX, and maybe some others */
+#ifdef LINUX
+#define POSIX_SETJMP
+#endif
+
 /* includes: */
 #include <sys/time.h>		/* timeval, time_t */
 #include <setjmp.h>		/* jmp_buf et al */
@@ -109,7 +117,11 @@
 #define PINF struct port_poop
 
 /* globals: */
+#ifdef POSIX_SETJMP
+sigjmp_buf jbuf;		/* timer crud */
+#else
 jmp_buf jbuf;			/* timer crud */
+#endif
 int jval = 0;			/* timer crud */
 int netfd = -1;
 int ofd = 0;			/* hexdump output fd */
@@ -235,7 +247,11 @@
   alarm (0);
   if (jval == 0)
     bail ("spurious timer interrupt!");
+#ifdef POSIX_SETJMP
+  siglongjmp (jbuf, jval);
+#else
   longjmp (jbuf, jval);
+#endif
 }
 
 /* arm_timer :
@@ -747,12 +763,21 @@
 
 /* wrap connect inside a timer, and hit it */
   arm_timer (1, o_wait);
+#ifdef POSIX_SETJMP
+  if (sigsetjmp (jbuf,1) == 0) {
+    rr = connect (nnetfd, (SA *)remend, sizeof (SA));
+  } else {				/* setjmp: connect failed... */
+    rr = -1;
+    errno = ETIMEDOUT;			/* fake it */
+  }
+#else
   if (setjmp (jbuf) == 0) {
     rr = connect (nnetfd, (SA *)remend, sizeof (SA));
   } else {				/* setjmp: connect failed... */
     rr = -1;
     errno = ETIMEDOUT;			/* fake it */
   }
+#endif
   arm_timer (0, 0);
   if (rr == 0)
     return (nnetfd);
@@ -824,7 +849,11 @@
   if (o_udpmode) {
     x = sizeof (SA);		/* retval for recvfrom */
     arm_timer (2, o_wait);		/* might as well timeout this, too */
+#ifdef POSIX_SETJMP
+    if (sigsetjmp (jbuf,1) == 0) {	/* do timeout for initial connect */
+#else
     if (setjmp (jbuf) == 0) {	/* do timeout for initial connect */
+#endif
       rr = recvfrom		/* and here we block... */
 	(nnetfd, bigbuf_net, BIGSIZ, MSG_PEEK, (SA *) remend, &x);
 Debug (("dolisten/recvfrom ding, rr = %d, netbuf %s ", rr, bigbuf_net))
@@ -849,10 +878,17 @@
 /* fall here for TCP */
   x = sizeof (SA);		/* retval for accept */
   arm_timer (2, o_wait);		/* wrap this in a timer, too; 0 = forever */
+#ifdef POSIX_SETJMP
+  if (sigsetjmp (jbuf,1) == 0) {
+    rr = accept (nnetfd, (SA *)remend, &x);
+  } else
+    goto dol_tmo;		/* timeout */
+#else
   if (setjmp (jbuf) == 0) {
     rr = accept (nnetfd, (SA *)remend, &x);
   } else
     goto dol_tmo;		/* timeout */
+#endif
   arm_timer (0, 0);
   close (nnetfd);		/* dump the old socket */
   nnetfd = rr;			/* here's our new one */