X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=networking%2Ftelnetd.c;h=a6bafa21df646536c4264b1d32b9a848513e6fd6;hb=9a4100cf53f75356854ce752374babf8135c3f42;hp=1de3abcc77510b22786ac8d5b46309afbbd0e501;hpb=26d88d6bbda628f0005115bbe0f85722db267793;p=oweals%2Fbusybox.git

diff --git a/networking/telnetd.c b/networking/telnetd.c
index 1de3abcc7..a6bafa21d 100644
--- a/networking/telnetd.c
+++ b/networking/telnetd.c
@@ -20,6 +20,78 @@
  * Vladimir Oleynik <dzo@simtreas.ru> 2001
  * Set process group corrections, initial busybox port
  */
+//config:config TELNETD
+//config:	bool "telnetd (12 kb)"
+//config:	default y
+//config:	select FEATURE_SYSLOG
+//config:	help
+//config:	A daemon for the TELNET protocol, allowing you to log onto the host
+//config:	running the daemon. Please keep in mind that the TELNET protocol
+//config:	sends passwords in plain text. If you can't afford the space for an
+//config:	SSH daemon and you trust your network, you may say 'y' here. As a
+//config:	more secure alternative, you should seriously consider installing the
+//config:	very small Dropbear SSH daemon instead:
+//config:		http://matt.ucc.asn.au/dropbear/dropbear.html
+//config:
+//config:	Note that for busybox telnetd to work you need several things:
+//config:	First of all, your kernel needs:
+//config:		  CONFIG_UNIX98_PTYS=y
+//config:
+//config:	Next, you need a /dev/pts directory on your root filesystem:
+//config:
+//config:		  $ ls -ld /dev/pts
+//config:		  drwxr-xr-x  2 root root 0 Sep 23 13:21 /dev/pts/
+//config:
+//config:	Next you need the pseudo terminal master multiplexer /dev/ptmx:
+//config:
+//config:		  $ ls -la /dev/ptmx
+//config:		  crw-rw-rw-  1 root tty 5, 2 Sep 23 13:55 /dev/ptmx
+//config:
+//config:	Any /dev/ttyp[0-9]* files you may have can be removed.
+//config:	Next, you need to mount the devpts filesystem on /dev/pts using:
+//config:
+//config:		  mount -t devpts devpts /dev/pts
+//config:
+//config:	You need to be sure that busybox has LOGIN and
+//config:	FEATURE_SUID enabled. And finally, you should make
+//config:	certain that busybox has been installed setuid root:
+//config:
+//config:		chown root.root /bin/busybox
+//config:		chmod 4755 /bin/busybox
+//config:
+//config:	with all that done, telnetd _should_ work....
+//config:
+//config:config FEATURE_TELNETD_STANDALONE
+//config:	bool "Support standalone telnetd (not inetd only)"
+//config:	default y
+//config:	depends on TELNETD
+//config:	help
+//config:	Selecting this will make telnetd able to run standalone.
+//config:
+//config:config FEATURE_TELNETD_INETD_WAIT
+//config:	bool "Support -w SEC option (inetd wait mode)"
+//config:	default y
+//config:	depends on FEATURE_TELNETD_STANDALONE
+//config:	help
+//config:	This option allows you to run telnetd in "inet wait" mode.
+//config:	Example inetd.conf line (note "wait", not usual "nowait"):
+//config:
+//config:	telnet stream tcp wait root /bin/telnetd telnetd -w10
+//config:
+//config:	In this example, inetd passes _listening_ socket_ as fd 0
+//config:	to telnetd when connection appears.
+//config:	telnetd will wait for connections until all existing
+//config:	connections are closed, and no new connections
+//config:	appear during 10 seconds. Then it exits, and inetd continues
+//config:	to listen for new connections.
+//config:
+//config:	This option is rarely used. "tcp nowait" is much more usual
+//config:	way of running tcp services, including telnetd.
+//config:	You most probably want to say N here.
+
+//applet:IF_TELNETD(APPLET(telnetd, BB_DIR_USR_SBIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_TELNETD) += telnetd.o
 
 //usage:#define telnetd_trivial_usage
 //usage:       "[OPTIONS]"
@@ -192,8 +264,16 @@ safe_write_to_pty_decode_iac(struct tsession *ts)
 		/* Literal 255 (emacs M-DEL) */
 		//bb_error_msg("255!");
 		rc = safe_write(ts->ptyfd, &buf[1], 1);
+		/*
+		 * If we went through buffered_IAC_for_pty==1 path,
+		 * bailing out on error like below messes up the buffer.
+		 * EAGAIN is highly unlikely here, other errors will be
+		 * repeated on next write, let's just skip error check.
+		 */
+#if 0
 		if (rc <= 0)
 			return rc;
+#endif
 		rc = 2;
 		goto update_and_return;
 	}
@@ -579,13 +659,15 @@ int telnetd_main(int argc UNUSED_PARAM, char **argv)
 #endif
 	INIT_G();
 
-	/* -w NUM, and implies -F. -w and -i don't mix */
-	IF_FEATURE_TELNETD_INETD_WAIT(opt_complementary = "wF:i--w:w--i";)
 	/* Even if !STANDALONE, we accept (and ignore) -i, thus people
 	 * don't need to guess whether it's ok to pass -i to us */
-	opt = getopt32(argv, "f:l:Ki"
+	opt = getopt32(argv, "^"
+			"f:l:Ki"
 			IF_FEATURE_TELNETD_STANDALONE("p:b:F")
-			IF_FEATURE_TELNETD_INETD_WAIT("Sw:+"),
+			IF_FEATURE_TELNETD_INETD_WAIT("Sw:+") /* -w NUM */
+			"\0"
+			/* -w implies -F. -w and -i don't mix */
+			IF_FEATURE_TELNETD_INETD_WAIT("wF:i--w:w--i"),
 			&G.issuefile, &G.loginpath
 			IF_FEATURE_TELNETD_STANDALONE(, &opt_portnbr, &opt_bindaddr)
 			IF_FEATURE_TELNETD_INETD_WAIT(, &sec_linger)