Don't shutdown nc(1)'s network socket when stdin closes. Matches *Hobbit*'s

original netcat and GNU netcat; revert to old behaviour with the new -N flag
if needed. After much discussion with otto deraadt tedu and Martin Pelikan.
ok deraadt@

2 files changed, 17 insertions, 7 deletions

diff --git a/src/usr.bin/nc/nc.1 b/src/usr.bin/nc/nc.1
index 232b6f5b6e..6fdb56e7e3 100644
--- a/src/usr.bin/nc/nc.1
+++ b/src/usr.bin/nc/nc.1
@@ -1,4 +1,4 @@
-.\"     $OpenBSD: nc.1,v 1.61 2012/07/07 15:33:02 haesbaert Exp $
+.\"     $OpenBSD: nc.1,v 1.62 2013/03/20 09:27:56 sthen Exp $
 .\"
 .\" Copyright (c) 1996 David Sacerdote
 .\" All rights reserved.
@@ -25,7 +25,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: July 7 2012 $
+.Dd $Mdocdate: March 20 2013 $
 .Dt NC 1
 .Os
 .Sh NAME
@@ -34,7 +34,7 @@
 .Sh SYNOPSIS
 .Nm nc
 .Bk -words
-.Op Fl 46DdhklnrStUuvz
+.Op Fl 46DdhklNnrStUuvz
 .Op Fl I Ar length
 .Op Fl i Ar interval
 .Op Fl O Ar length
@@ -137,6 +137,10 @@ options.
 Additionally, any timeouts specified with the
 .Fl w
 option are ignored.
+.It Fl N
+.Xr shutdown 2
+the network socket after EOF on the input.
+Some servers require this to finish their work.
 .It Fl n
 Do not do any DNS or service lookups on any specified addresses,
 hostnames or ports.
diff --git a/src/usr.bin/nc/netcat.c b/src/usr.bin/nc/netcat.c
index 93338dac37..33246d7a74 100644
--- a/src/usr.bin/nc/netcat.c
+++ b/src/usr.bin/nc/netcat.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: netcat.c,v 1.110 2013/03/12 02:57:37 deraadt Exp $ */
+/* $OpenBSD: netcat.c,v 1.111 2013/03/20 09:27:56 sthen Exp $ */
 /*
  * Copyright (c) 2001 Eric Jackson <ericj@monkey.org>
  *
@@ -69,6 +69,7 @@ int	dflag;					/* detached, no stdin */
 unsigned int iflag;                             /* Interval Flag */
 int     kflag;                                  /* More than one connect */
 int     lflag;                                  /* Bind to local port */
+int     Nflag;                                  /* shutdown() network socket */
 int     nflag;                                  /* Don't do name look up */
 char   *Pflag;                                  /* Proxy username */
 char   *pflag;                                  /* Localport flag */
@@ -131,7 +132,7 @@ main(int argc, char *argv[])
         sv = NULL;
 
         while ((ch = getopt(argc, argv,
-            "46DdhI:i:klnO:P:p:rSs:tT:UuV:vw:X:x:z")) != -1) {
+            "46DdhI:i:klNnO:P:p:rSs:tT:UuV:vw:X:x:z")) != -1) {
                 switch (ch) {
                 case '4':
                         family = AF_INET;
@@ -169,6 +170,9 @@ main(int argc, char *argv[])
                 case 'l':
                         lflag = 1;
                         break;
+                case 'N':
+                        Nflag = 1;
+                        break;
                 case 'n':
                         nflag = 1;
                         break;
@@ -771,7 +775,8 @@ readwrite(int nfd)
                         if ((n = read(wfd, buf, plen)) < 0)
                                 return;
                         else if (n == 0) {
-                                shutdown(nfd, SHUT_WR);
+                                if (Nflag)
+                                        shutdown(nfd, SHUT_WR);
                                 pfd[1].fd = -1;
                                 pfd[1].events = 0;
                         } else {
@@ -1014,6 +1019,7 @@ help(void)
         \t-i secs\t     Delay interval for lines sent, ports scanned\n\
         \t-k            Keep inbound sockets open for multiple connects\n\
         \t-l            Listen mode, for inbound connects\n\
+        \t-N            Shutdown the network socket after EOF on stdin\n\
         \t-n            Suppress name/port resolutions\n\
         \t-O length     TCP send buffer length\n\
         \t-P proxyuser\tUsername for proxy authentication\n\
@@ -1039,7 +1045,7 @@ void
 usage(int ret)
 {
         fprintf(stderr,
-            "usage: nc [-46DdhklnrStUuvz] [-I length] [-i interval] [-O length]\n"
+            "usage: nc [-46DdhklNnrStUuvz] [-I length] [-i interval] [-O length]\n"
             "\t  [-P proxy_username] [-p source_port] [-s source] [-T ToS]\n"
             "\t  [-V rtable] [-w timeout] [-X proxy_protocol]\n"
             "\t  [-x proxy_address[:port]] [destination] [port]\n");