Forward port patch from Przemyslaw Czerpak <druzus@polbox.com>:

 1. busybox-telnet dosn't inform server about the size of terminal screen.
    In the world of xterminals and frame buffers it's rather horrible
    to use fixed 80x24 region in upper-left corner of screen/window.

 2. If client sends character 0x0d to the server then sends character 0x0a
   the server eat the second byte (0x0a) - it's described in telnet RFC.
    Client should send two bytes ( 0x0d + 0x0a or 0x0d + 0x00 ) insted of
    one 0x0d byte.

 3. busybox telnet implementation wasn't 8bit clean (look at 0xff byte).
    I need it because I have to use binray transfer like rz/sz. So when
    I resloved the problem (2) I corrected this one two.

This also contains a small cleanup patch from vodz, and some minor editing
by me.

1 files changed, 77 insertions, 11 deletions

diff --git a/networking/telnet.c b/networking/telnet.c
index d09a9d558..93eda56e1 100644
--- a/networking/telnet.c
+++ b/networking/telnet.c
@@ -46,6 +46,10 @@
 #include <netdb.h>
 #include "busybox.h"
 
+#ifdef CONFIG_FEATURE_AUTOWIDTH
+#   include <sys/ioctl.h>
+#endif
+
 #if 0
 static const int DOTRACE = 1;
 #endif
@@ -140,6 +144,10 @@ static int one = 1;
 static char *ttype;
 #endif
 
+#ifdef CONFIG_FEATURE_AUTOWIDTH
+static int win_width, win_height;
+#endif
+
 static void doexit(int ev)
 {
         cookmode();
@@ -202,22 +210,38 @@ static void handlenetoutput(int len)
          *      stream  like writing twice every sequence of FF:s (thus doing
          *      many write()s. But I think interactive telnet application does
          *      not need to be 100% 8-bit clean, so changing every 0xff:s to
-         *      0x7f:s */
-
-        int i;
+         *      0x7f:s
+         *
+         *      2002-mar-21, Przemyslaw Czerpak (druzus@polbox.com)
+         *      I don't agree.
+         *      first - I cannot use programs like sz/rz
+         *      second - the 0x0D is sent as one character and if the next
+         *               char is 0x0A then it's eaten by a server side.
+         *      third - whay doy you have to make 'many write()s'?
+         *              I don't understand.
+         *      So I implemented it. It's realy useful for me. I hope that
+         *      others people will find it interesting to.
+         */
+
+        int i, j;
         byte * p = G.buf;
+        byte outbuf[4*DATABUFSIZE];
 
-        for (i = len; i > 0; i--, p++)
+        for (i = len, j = 0; i > 0; i--, p++)
         {
                 if (*p == 0x1d)
                 {
                         conescape();
                         return;
                 }
+                outbuf[j++] = *p;
                 if (*p == 0xff)
-                        *p = 0x7f;
+                    outbuf[j++] = 0xff;
+                else if (*p == 0x0d)
+                    outbuf[j++] = 0x00;
         }
-        write(G.netfd, G.buf, len);
+        if (j > 0 )
+            write(G.netfd, outbuf, j);
 }
 
 
@@ -346,6 +370,26 @@ static void putiac_subopt(byte c, char *str)
 }
 #endif
 
+#ifdef CONFIG_FEATURE_AUTOWIDTH
+static void putiac_naws(byte c, int x, int y)
+{
+        if (G.iaclen + 9 > IACBUFSIZE)
+                iacflush();
+
+        putiac(IAC);
+        putiac(SB);
+        putiac(c);
+
+        putiac((x >> 8) & 0xff);
+        putiac(x & 0xff);
+        putiac((y >> 8) & 0xff);
+        putiac(y & 0xff);
+
+        putiac(IAC);
+        putiac(SE);
+}
+#endif
+
 /* void putiacstring (subneg strings) */
 
 /* ******************************* */
@@ -466,23 +510,37 @@ static inline void to_ttype(void)
 }
 #endif
 
+#ifdef CONFIG_FEATURE_AUTOWIDTH
+static inline void to_naws()
+{ 
+        /* Tell server we will do NAWS */
+        putiac2(WILL, TELOPT_NAWS);
+        return;
+}         
+#endif
+
 static void telopt(byte c)
 {
         switch (c)
         {
-        case TELOPT_ECHO:               to_echo();             break;
-        case TELOPT_SGA:                to_sga();              break;
+                case TELOPT_ECHO:               to_echo(c);     break;
+                case TELOPT_SGA:                to_sga(c);      break;
 #ifdef CONFIG_FEATURE_TELNET_TTYPE
-        case TELOPT_TTYPE:              to_ttype();    break;
+                case TELOPT_TTYPE:              to_ttype(c);break;
 #endif
-        default:                                to_notsup(c);   break;
+#ifdef CONFIG_FEATURE_AUTOWIDTH
+                case TELOPT_NAWS:               to_naws(c);
+                                                                putiac_naws(c, win_width, win_height);
+                                                                break;
+#endif
+                default:                        to_notsup(c);   break;
         }
 }
 
 
 /* ******************************* */
 
-/* subnegotiation -- ignore all (except TTYPE) */
+/* subnegotiation -- ignore all (except TTYPE,NAWS) */
 
 static int subneg(byte c)
 {
@@ -536,6 +594,14 @@ extern int telnet_main(int argc, char** argv)
         int maxfd;
 #endif  
 
+#ifdef CONFIG_FEATURE_AUTOWIDTH
+    struct winsize winp;
+    if( ioctl(0, TIOCGWINSZ, &winp) == 0 ) {
+        win_width  = winp.ws_col;
+        win_height = winp.ws_row;
+    }
+#endif
+
 #ifdef CONFIG_FEATURE_TELNET_TTYPE
     ttype = getenv("TERM");
 #endif