X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=networking%2Ftelnet.c;h=12d1970fa98ab318a1a24dd440c61c4610492519;hb=361b1a6884bc9d4f5cece22d0eb9fe5eae17bda7;hp=1341572732a7928b222211bef5c682050dd4bda4;hpb=baca1759129945fcd03d96ccc840892401b5a1af;p=oweals%2Fbusybox.git

diff --git a/networking/telnet.c b/networking/telnet.c
index 134157273..12d1970fa 100644
--- a/networking/telnet.c
+++ b/networking/telnet.c
@@ -8,7 +8,7 @@
  * Created: Thu Apr  7 13:29:41 1994 too
  * Last modified: Fri Jun  9 14:34:24 2000 too
  *
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  *
  * HISTORY
  * Revision 3.1  1994/04/17  11:31:54  too
@@ -21,10 +21,9 @@
  *
  */
 
-#include <termios.h>
 #include <arpa/telnet.h>
 #include <netinet/in.h>
-#include "busybox.h"
+#include "libbb.h"
 
 #ifdef DOTRACE
 #define TRACE(x, y) do { if (x) printf y; } while (0)
@@ -32,10 +31,10 @@
 #define TRACE(x, y)
 #endif
 
-#define DATABUFSIZE  128
-#define IACBUFSIZE   128
-
 enum {
+	DATABUFSIZE = 128,
+	IACBUFSIZE  = 128,
+
 	CHM_TRY = 0,
 	CHM_ON = 1,
 	CHM_OFF = 2,
@@ -50,40 +49,39 @@ enum {
 	TS_SUB2 = 5,
 };
 
-#define WriteCS(fd, str) write(fd, str, sizeof str -1)
-
 typedef unsigned char byte;
 
-/* use globals to reduce size ??? */ /* test this hypothesis later */
-static struct Globalvars {
-	int		netfd; /* console fd:s are 0 and 1 (and 2) */
-    /* same buffer used both for network and console read/write */
-	char    buf[DATABUFSIZE]; /* allocating so static size is smaller */
+enum { netfd = 3 };
+
+struct globals {
+	int	iaclen; /* could even use byte, but it's a loss on x86 */
 	byte	telstate; /* telnet negotiation state from network input */
 	byte	telwish;  /* DO, DONT, WILL, WONT */
 	byte    charmode;
 	byte    telflags;
-	byte	gotsig;
 	byte	do_termios;
+#if ENABLE_FEATURE_TELNET_TTYPE
+	char	*ttype;
+#endif
+#if ENABLE_FEATURE_TELNET_AUTOLOGIN
+	const char *autologin;
+#endif
+#if ENABLE_FEATURE_AUTOWIDTH
+	unsigned win_width, win_height;
+#endif
+	/* same buffer used both for network and console read/write */
+	char    buf[DATABUFSIZE];
 	/* buffer to handle telnet negotiations */
 	char    iacbuf[IACBUFSIZE];
-	short	iaclen; /* could even use byte */
 	struct termios termios_def;
 	struct termios termios_raw;
-} G;
-
-#define xUSE_GLOBALVAR_PTR /* xUSE... -> don't use :D (makes smaller code) */
-
-#ifdef USE_GLOBALVAR_PTR
-struct Globalvars * Gptr;
-#define G (*Gptr)
-#endif
-
-static void iacflush(void)
-{
-	write(G.netfd, G.iacbuf, G.iaclen);
-	G.iaclen = 0;
-}
+} FIX_ALIASING;
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define INIT_G() do { \
+	struct G_sizecheck { \
+		char G_sizecheck[sizeof(G) > COMMON_BUFSIZE ? -1 : 1]; \
+	}; \
+} while (0)
 
 /* Function prototypes */
 static void rawmode(void);
@@ -93,55 +91,48 @@ static void will_charmode(void);
 static void telopt(byte c);
 static int subneg(byte c);
 
-/* Some globals */
-#ifdef CONFIG_FEATURE_TELNET_TTYPE
-static char *ttype;
-#endif
-
-#ifdef CONFIG_FEATURE_TELNET_AUTOLOGIN
-static const char *autologin;
-#endif
+static void iac_flush(void)
+{
+	write(netfd, G.iacbuf, G.iaclen);
+	G.iaclen = 0;
+}
 
-#ifdef CONFIG_FEATURE_AUTOWIDTH
-static int win_width, win_height;
-#endif
+#define write_str(fd, str) write(fd, str, sizeof(str) - 1)
 
+static void doexit(int ev) NORETURN;
 static void doexit(int ev)
 {
 	cookmode();
 	exit(ev);
 }
 
-static void conescape(void)
+static void con_escape(void)
 {
 	char b;
 
-	if (G.gotsig)	/* came from line  mode... go raw */
+	if (bb_got_signal) /* came from line mode... go raw */
 		rawmode();
 
-	WriteCS(1, "\r\nConsole escape. Commands are:\r\n\n"
+	write_str(1, "\r\nConsole escape. Commands are:\r\n\n"
 			" l	go to line mode\r\n"
 			" c	go to character mode\r\n"
 			" z	suspend telnet\r\n"
 			" e	exit telnet\r\n");
 
-	if (read(0, &b, 1) <= 0)
-		doexit(1);
+	if (read(STDIN_FILENO, &b, 1) <= 0)
+		doexit(EXIT_FAILURE);
 
-	switch (b)
-	{
+	switch (b) {
 	case 'l':
-		if (!G.gotsig)
-		{
+		if (!bb_got_signal) {
 			do_linemode();
-			goto rrturn;
+			goto ret;
 		}
 		break;
 	case 'c':
-		if (G.gotsig)
-		{
+		if (bb_got_signal) {
 			will_charmode();
-			goto rrturn;
+			goto ret;
 		}
 		break;
 	case 'z':
@@ -150,46 +141,43 @@ static void conescape(void)
 		rawmode();
 		break;
 	case 'e':
-		doexit(0);
+		doexit(EXIT_SUCCESS);
 	}
 
-	WriteCS(1, "continuing...\r\n");
+	write_str(1, "continuing...\r\n");
 
-	if (G.gotsig)
+	if (bb_got_signal)
 		cookmode();
-
- rrturn:
-	G.gotsig = 0;
-
+ ret:
+	bb_got_signal = 0;
 }
-static void handlenetoutput(int len)
+
+static void handle_net_output(int len)
 {
-	/*	here we could do smart tricks how to handle 0xFF:s in output
-	 *	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
+	/* here we could do smart tricks how to handle 0xFF:s in output
+	 * 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
 	 *
-	 *	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.
+	 * 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 - why do you have to make 'many write()s'?
+	 *	I don't understand.
+	 * So I implemented it. It's really useful for me. I hope that
+	 * other people will find it interesting too.
 	 */
 
 	int i, j;
-	byte * p = (byte*)G.buf;
+	byte *p = (byte*)G.buf;
 	byte outbuf[4*DATABUFSIZE];
 
-	for (i = len, j = 0; i > 0; i--, p++)
-	{
-		if (*p == 0x1d)
-		{
-			conescape();
+	for (i = len, j = 0; i > 0; i--, p++) {
+		if (*p == 0x1d) {
+			con_escape();
 			return;
 		}
 		outbuf[j++] = *p;
@@ -198,191 +186,174 @@ static void handlenetoutput(int len)
 		else if (*p == 0x0d)
 			outbuf[j++] = 0x00;
 	}
-	if (j > 0 )
-		write(G.netfd, outbuf, j);
+	if (j > 0)
+		write(netfd, outbuf, j);
 }
 
-
-static void handlenetinput(int len)
+static void handle_net_input(int len)
 {
 	int i;
 	int cstart = 0;
 
-	for (i = 0; i < len; i++)
-	{
+	for (i = 0; i < len; i++) {
 		byte c = G.buf[i];
 
-		if (G.telstate == 0) /* most of the time state == 0 */
-		{
-			if (c == IAC)
-			{
+		if (G.telstate == 0) { /* most of the time state == 0 */
+			if (c == IAC) {
 				cstart = i;
 				G.telstate = TS_IAC;
 			}
+			continue;
 		}
-		else
-			switch (G.telstate)
-			 {
-			 case TS_0:
-				 if (c == IAC)
-					 G.telstate = TS_IAC;
-				 else
-					 G.buf[cstart++] = c;
-				 break;
-
-			 case TS_IAC:
-				 if (c == IAC) /* IAC IAC -> 0xFF */
-				 {
-					 G.buf[cstart++] = c;
-					 G.telstate = TS_0;
-					 break;
-				 }
-				 /* else */
-				 switch (c)
-				 {
-				 case SB:
-					 G.telstate = TS_SUB1;
-					 break;
-				 case DO:
-				 case DONT:
-				 case WILL:
-				 case WONT:
-					 G.telwish =  c;
-					 G.telstate = TS_OPT;
-					 break;
-				 default:
-					 G.telstate = TS_0;	/* DATA MARK must be added later */
-				 }
-				 break;
-			 case TS_OPT: /* WILL, WONT, DO, DONT */
-				 telopt(c);
-				 G.telstate = TS_0;
-				 break;
-			 case TS_SUB1: /* Subnegotiation */
-			 case TS_SUB2: /* Subnegotiation */
-				 if (subneg(c))
-					 G.telstate = TS_0;
-				 break;
-			 }
-	}
-	if (G.telstate)
-	{
-		if (G.iaclen)			iacflush();
-		if (G.telstate == TS_0)	G.telstate = 0;
+		switch (G.telstate) {
+		case TS_0:
+			if (c == IAC)
+				G.telstate = TS_IAC;
+			else
+				G.buf[cstart++] = c;
+			break;
 
+		case TS_IAC:
+			if (c == IAC) { /* IAC IAC -> 0xFF */
+				G.buf[cstart++] = c;
+				G.telstate = TS_0;
+				break;
+			}
+			/* else */
+			switch (c) {
+			case SB:
+				G.telstate = TS_SUB1;
+				break;
+			case DO:
+			case DONT:
+			case WILL:
+			case WONT:
+				G.telwish =  c;
+				G.telstate = TS_OPT;
+				break;
+			default:
+				G.telstate = TS_0;	/* DATA MARK must be added later */
+			}
+			break;
+		case TS_OPT: /* WILL, WONT, DO, DONT */
+			telopt(c);
+			G.telstate = TS_0;
+			break;
+		case TS_SUB1: /* Subnegotiation */
+		case TS_SUB2: /* Subnegotiation */
+			if (subneg(c))
+				G.telstate = TS_0;
+			break;
+		}
+	}
+	if (G.telstate) {
+		if (G.iaclen)
+			iac_flush();
+		if (G.telstate == TS_0)
+			G.telstate = 0;
 		len = cstart;
 	}
 
 	if (len)
-		write(1, G.buf, len);
+		write(STDOUT_FILENO, G.buf, len);
 }
 
-
-/* ******************************* */
-
-static void putiac(int c)
+static void put_iac(int c)
 {
 	G.iacbuf[G.iaclen++] = c;
 }
 
-
-static void putiac2(byte wwdd, byte c)
+static void put_iac2(byte wwdd, byte c)
 {
 	if (G.iaclen + 3 > IACBUFSIZE)
-		iacflush();
+		iac_flush();
 
-	putiac(IAC);
-	putiac(wwdd);
-	putiac(c);
+	put_iac(IAC);
+	put_iac(wwdd);
+	put_iac(c);
 }
 
-#ifdef CONFIG_FEATURE_TELNET_TTYPE
-static void putiac_subopt(byte c, char *str)
+#if ENABLE_FEATURE_TELNET_TTYPE
+static void put_iac_subopt(byte c, char *str)
 {
-	int	len = strlen(str) + 6;   // ( 2 + 1 + 1 + strlen + 2 )
+	int len = strlen(str) + 6;   // ( 2 + 1 + 1 + strlen + 2 )
 
 	if (G.iaclen + len > IACBUFSIZE)
-		iacflush();
+		iac_flush();
 
-	putiac(IAC);
-	putiac(SB);
-	putiac(c);
-	putiac(0);
+	put_iac(IAC);
+	put_iac(SB);
+	put_iac(c);
+	put_iac(0);
 
 	while (*str)
-		putiac(*str++);
+		put_iac(*str++);
 
-	putiac(IAC);
-	putiac(SE);
+	put_iac(IAC);
+	put_iac(SE);
 }
 #endif
 
-#ifdef CONFIG_FEATURE_TELNET_AUTOLOGIN
-static void putiac_subopt_autologin(void)
+#if ENABLE_FEATURE_TELNET_AUTOLOGIN
+static void put_iac_subopt_autologin(void)
 {
-	int len = strlen(autologin) + 6;	// (2 + 1 + 1 + strlen + 2)
-	const char *user = "USER";
+	int len = strlen(G.autologin) + 6;	// (2 + 1 + 1 + strlen + 2)
+	const char *p = "USER";
 
 	if (G.iaclen + len > IACBUFSIZE)
-		iacflush();
+		iac_flush();
 
-	putiac(IAC);
-	putiac(SB);
-	putiac(TELOPT_NEW_ENVIRON);
-	putiac(TELQUAL_IS);
-	putiac(NEW_ENV_VAR);
+	put_iac(IAC);
+	put_iac(SB);
+	put_iac(TELOPT_NEW_ENVIRON);
+	put_iac(TELQUAL_IS);
+	put_iac(NEW_ENV_VAR);
 
-	while (*user)
-		putiac(*user++);
+	while (*p)
+		put_iac(*p++);
 
-	putiac(NEW_ENV_VALUE);
+	put_iac(NEW_ENV_VALUE);
 
-	while (*autologin)
-		putiac(*autologin++);
+	p = G.autologin;
+	while (*p)
+		put_iac(*p++);
 
-	putiac(IAC);
-	putiac(SE);
+	put_iac(IAC);
+	put_iac(SE);
 }
 #endif
 
-#ifdef CONFIG_FEATURE_AUTOWIDTH
-static void putiac_naws(byte c, int x, int y)
+#if ENABLE_FEATURE_AUTOWIDTH
+static void put_iac_naws(byte c, int x, int y)
 {
 	if (G.iaclen + 9 > IACBUFSIZE)
-		iacflush();
+		iac_flush();
 
-	putiac(IAC);
-	putiac(SB);
-	putiac(c);
+	put_iac(IAC);
+	put_iac(SB);
+	put_iac(c);
 
-	putiac((x >> 8) & 0xff);
-	putiac(x & 0xff);
-	putiac((y >> 8) & 0xff);
-	putiac(y & 0xff);
+	put_iac((x >> 8) & 0xff);
+	put_iac(x & 0xff);
+	put_iac((y >> 8) & 0xff);
+	put_iac(y & 0xff);
 
-	putiac(IAC);
-	putiac(SE);
+	put_iac(IAC);
+	put_iac(SE);
 }
 #endif
 
-/* void putiacstring (subneg strings) */
-
-/* ******************************* */
-
-static char const escapecharis[] = "\r\nEscape character is ";
+static char const escapecharis[] ALIGN1 = "\r\nEscape character is ";
 
 static void setConMode(void)
 {
-	if (G.telflags & UF_ECHO)
-	{
+	if (G.telflags & UF_ECHO) {
 		if (G.charmode == CHM_TRY) {
 			G.charmode = CHM_ON;
 			printf("\r\nEntering character mode%s'^]'.\r\n", escapecharis);
 			rawmode();
 		}
-	}
-	else
-	{
+	} else {
 		if (G.charmode != CHM_OFF) {
 			G.charmode = CHM_OFF;
 			printf("\r\nEntering line mode%s'^C'.\r\n", escapecharis);
@@ -391,17 +362,15 @@ static void setConMode(void)
 	}
 }
 
-/* ******************************* */
-
 static void will_charmode(void)
 {
 	G.charmode = CHM_TRY;
 	G.telflags |= (UF_ECHO | UF_SGA);
 	setConMode();
 
-	putiac2(DO, TELOPT_ECHO);
-	putiac2(DO, TELOPT_SGA);
-	iacflush();
+	put_iac2(DO, TELOPT_ECHO);
+	put_iac2(DO, TELOPT_SGA);
+	iac_flush();
 }
 
 static void do_linemode(void)
@@ -410,94 +379,91 @@ static void do_linemode(void)
 	G.telflags &= ~(UF_ECHO | UF_SGA);
 	setConMode();
 
-	putiac2(DONT, TELOPT_ECHO);
-	putiac2(DONT, TELOPT_SGA);
-	iacflush();
+	put_iac2(DONT, TELOPT_ECHO);
+	put_iac2(DONT, TELOPT_SGA);
+	iac_flush();
 }
 
-/* ******************************* */
-
 static void to_notsup(char c)
 {
-	if      (G.telwish == WILL)	putiac2(DONT, c);
-	else if (G.telwish == DO)	putiac2(WONT, c);
+	if (G.telwish == WILL)
+		put_iac2(DONT, c);
+	else if (G.telwish == DO)
+		put_iac2(WONT, c);
 }
 
 static void to_echo(void)
 {
 	/* if server requests ECHO, don't agree */
-	if      (G.telwish == DO) {	putiac2(WONT, TELOPT_ECHO);	return; }
-	else if (G.telwish == DONT)	return;
+	if (G.telwish == DO) {
+		put_iac2(WONT, TELOPT_ECHO);
+		return;
+	}
+	if (G.telwish == DONT)
+		return;
 
-	if (G.telflags & UF_ECHO)
-	{
+	if (G.telflags & UF_ECHO) {
 		if (G.telwish == WILL)
 			return;
-	}
-	else
-		if (G.telwish == WONT)
-			return;
+	} else if (G.telwish == WONT)
+		return;
 
 	if (G.charmode != CHM_OFF)
 		G.telflags ^= UF_ECHO;
 
 	if (G.telflags & UF_ECHO)
-		putiac2(DO, TELOPT_ECHO);
+		put_iac2(DO, TELOPT_ECHO);
 	else
-		putiac2(DONT, TELOPT_ECHO);
+		put_iac2(DONT, TELOPT_ECHO);
 
 	setConMode();
-	WriteCS(1, "\r\n");  /* sudden modec */
+	full_write1_str("\r\n");  /* sudden modec */
 }
 
 static void to_sga(void)
 {
 	/* daemon always sends will/wont, client do/dont */
 
-	if (G.telflags & UF_SGA)
-	{
+	if (G.telflags & UF_SGA) {
 		if (G.telwish == WILL)
 			return;
-	}
-	else
-		if (G.telwish == WONT)
-			return;
+	} else if (G.telwish == WONT)
+		return;
 
-	if ((G.telflags ^= UF_SGA) & UF_SGA) /* toggle */
-		putiac2(DO, TELOPT_SGA);
+	G.telflags ^= UF_SGA; /* toggle */
+	if (G.telflags & UF_SGA)
+		put_iac2(DO, TELOPT_SGA);
 	else
-		putiac2(DONT, TELOPT_SGA);
+		put_iac2(DONT, TELOPT_SGA);
 }
 
-#ifdef CONFIG_FEATURE_TELNET_TTYPE
+#if ENABLE_FEATURE_TELNET_TTYPE
 static void to_ttype(void)
 {
 	/* Tell server we will (or won't) do TTYPE */
-
-	if(ttype)
-		putiac2(WILL, TELOPT_TTYPE);
+	if (G.ttype)
+		put_iac2(WILL, TELOPT_TTYPE);
 	else
-		putiac2(WONT, TELOPT_TTYPE);
+		put_iac2(WONT, TELOPT_TTYPE);
 }
 #endif
 
-#ifdef CONFIG_FEATURE_TELNET_AUTOLOGIN
+#if ENABLE_FEATURE_TELNET_AUTOLOGIN
 static void to_new_environ(void)
 {
 	/* Tell server we will (or will not) do AUTOLOGIN */
-
-	if (autologin)
-		putiac2(WILL, TELOPT_NEW_ENVIRON);
+	if (G.autologin)
+		put_iac2(WILL, TELOPT_NEW_ENVIRON);
 	else
-		putiac2(WONT, TELOPT_NEW_ENVIRON);
+		put_iac2(WONT, TELOPT_NEW_ENVIRON);
 }
 #endif
 
-#ifdef CONFIG_FEATURE_AUTOWIDTH
+#if ENABLE_FEATURE_AUTOWIDTH
 static void to_naws(void)
 {
 	/* Tell server we will do NAWS */
-	putiac2(WILL, TELOPT_NAWS);
+	put_iac2(WILL, TELOPT_NAWS);
 }
 #endif
 
@@ -508,18 +474,18 @@ static void telopt(byte c)
 		to_echo(); break;
 	case TELOPT_SGA:
 		to_sga(); break;
-#ifdef CONFIG_FEATURE_TELNET_TTYPE
+#if ENABLE_FEATURE_TELNET_TTYPE
 	case TELOPT_TTYPE:
 		to_ttype(); break;
 #endif
-#ifdef CONFIG_FEATURE_TELNET_AUTOLOGIN
+#if ENABLE_FEATURE_TELNET_AUTOLOGIN
 	case TELOPT_NEW_ENVIRON:
 		to_new_environ(); break;
 #endif
-#ifdef CONFIG_FEATURE_AUTOWIDTH
+#if ENABLE_FEATURE_AUTOWIDTH
 	case TELOPT_NAWS:
 		to_naws();
-		putiac_naws(c, win_width, win_height);
+		put_iac_naws(c, G.win_width, G.win_height);
 		break;
 #endif
 	default:
@@ -528,27 +494,22 @@ static void telopt(byte c)
 	}
 }
 
-
-/* ******************************* */
-
 /* subnegotiation -- ignore all (except TTYPE,NAWS) */
-
 static int subneg(byte c)
 {
-	switch (G.telstate)
-	{
+	switch (G.telstate) {
 	case TS_SUB1:
 		if (c == IAC)
 			G.telstate = TS_SUB2;
-#ifdef CONFIG_FEATURE_TELNET_TTYPE
+#if ENABLE_FEATURE_TELNET_TTYPE
 		else
-		if (c == TELOPT_TTYPE)
-			putiac_subopt(TELOPT_TTYPE,ttype);
+		if (c == TELOPT_TTYPE && G.ttype)
+			put_iac_subopt(TELOPT_TTYPE, G.ttype);
 #endif
-#ifdef CONFIG_FEATURE_TELNET_AUTOLOGIN
+#if ENABLE_FEATURE_TELNET_AUTOLOGIN
 		else
-		if (c == TELOPT_NEW_ENVIRON)
-			putiac_subopt_autologin();
+		if (c == TELOPT_NEW_ENVIRON && G.autologin)
+			put_iac_subopt_autologin();
 #endif
 		break;
 	case TS_SUB2:
@@ -560,26 +521,23 @@ static int subneg(byte c)
 	return FALSE;
 }
 
-/* ******************************* */
-
-static void fgotsig(int sig)
-{
-	G.gotsig = sig;
-}
-
-
 static void rawmode(void)
 {
-	if (G.do_termios) tcsetattr(0, TCSADRAIN, &G.termios_raw);
+	if (G.do_termios)
+		tcsetattr(0, TCSADRAIN, &G.termios_raw);
 }
 
 static void cookmode(void)
 {
-	if (G.do_termios) tcsetattr(0, TCSADRAIN, &G.termios_def);
+	if (G.do_termios)
+		tcsetattr(0, TCSADRAIN, &G.termios_def);
 }
 
-int telnet_main(int argc, char** argv);
-int telnet_main(int argc, char** argv)
+/* poll gives smaller (-70 bytes) code */
+#define USE_POLL 1
+
+int telnet_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int telnet_main(int argc UNUSED_PARAM, char **argv)
 {
 	char *host;
 	int port;
@@ -591,15 +549,15 @@ int telnet_main(int argc, char** argv)
 	int maxfd;
 #endif
 
-#ifdef CONFIG_FEATURE_AUTOWIDTH
-	get_terminal_width_height(0, &win_width, &win_height);
-#endif
+	INIT_G();
 
-#ifdef CONFIG_FEATURE_TELNET_TTYPE
-	ttype = getenv("TERM");
+#if ENABLE_FEATURE_AUTOWIDTH
+	get_terminal_width_height(0, &G.win_width, &G.win_height);
 #endif
 
-	/* memset(&G, 0, sizeof G); - already is */
+#if ENABLE_FEATURE_TELNET_TTYPE
+	G.ttype = getenv("TERM");
+#endif
 
 	if (tcgetattr(0, &G.termios_def) >= 0) {
 		G.do_termios = 1;
@@ -607,12 +565,9 @@ int telnet_main(int argc, char** argv)
 		cfmakeraw(&G.termios_raw);
 	}
 
-	if (argc < 2)
-		bb_show_usage();
-
-#ifdef CONFIG_FEATURE_TELNET_AUTOLOGIN
-	if (1 & getopt32(argc, argv, "al:", &autologin))
-		autologin = getenv("USER");
+#if ENABLE_FEATURE_TELNET_AUTOLOGIN
+	if (1 & getopt32(argv, "al:", &G.autologin))
+		G.autologin = getenv("USER");
 	argv += optind;
 #else
 	argv++;
@@ -624,20 +579,20 @@ int telnet_main(int argc, char** argv)
 	if (*argv) /* extra params?? */
 		bb_show_usage();
 
-	G.netfd = create_and_connect_stream_or_die(host, port);
+	xmove_fd(create_and_connect_stream_or_die(host, port), netfd);
 
-	setsockopt(G.netfd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
+	setsockopt(netfd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
 
-	signal(SIGINT, fgotsig);
+	signal(SIGINT, record_signo);
 
 #ifdef USE_POLL
-	ufds[0].fd = 0; ufds[1].fd = G.netfd;
+	ufds[0].fd = 0; ufds[1].fd = netfd;
 	ufds[0].events = ufds[1].events = POLLIN;
 #else
 	FD_ZERO(&readfds);
-	FD_SET(0, &readfds);
-	FD_SET(G.netfd, &readfds);
-	maxfd = G.netfd + 1;
+	FD_SET(STDIN_FILENO, &readfds);
+	FD_SET(netfd, &readfds);
+	maxfd = netfd + 1;
 #endif
 
 	while (1) {
@@ -653,45 +608,40 @@ int telnet_main(int argc, char** argv)
 			/* timeout */
 		case -1:
 			/* error, ignore and/or log something, bay go to loop */
-			if (G.gotsig)
-				conescape();
+			if (bb_got_signal)
+				con_escape();
 			else
 				sleep(1);
 			break;
 		default:
 
 #ifdef USE_POLL
-			if (ufds[0].revents) /* well, should check POLLIN, but ... */
+			if (ufds[0].revents)
 #else
-			if (FD_ISSET(0, &rfds))
+			if (FD_ISSET(STDIN_FILENO, &rfds))
 #endif
 			{
-				len = read(0, G.buf, DATABUFSIZE);
-
+				len = safe_read(STDIN_FILENO, G.buf, DATABUFSIZE);
 				if (len <= 0)
-					doexit(0);
-
+					doexit(EXIT_SUCCESS);
 				TRACE(0, ("Read con: %d\n", len));
-
-				handlenetoutput(len);
+				handle_net_output(len);
 			}
 
 #ifdef USE_POLL
-			if (ufds[1].revents) /* well, should check POLLIN, but ... */
+			if (ufds[1].revents)
 #else
-			if (FD_ISSET(G.netfd, &rfds))
+			if (FD_ISSET(netfd, &rfds))
 #endif
 			{
-				len = read(G.netfd, G.buf, DATABUFSIZE);
-
+				len = safe_read(netfd, G.buf, DATABUFSIZE);
 				if (len <= 0) {
-					WriteCS(1, "Connection closed by foreign host.\r\n");
-					doexit(1);
+					full_write1_str("Connection closed by foreign host\r\n");
+					doexit(EXIT_FAILURE);
 				}
-				TRACE(0, ("Read netfd (%d): %d\n", G.netfd, len));
-
-				handlenetinput(len);
+				TRACE(0, ("Read netfd (%d): %d\n", netfd, len));
+				handle_net_input(len);
 			}
 		}
-	}
+	} /* while (1) */
 }