telnetd: ifdef out a buggy error handling code path

Here, not handling the error is would just eat one input 0xff char.
Correct handling would need even more corner case handling,
as-is buggy handling corrupts the buffer.
Since we just been told by kernel that pty is ready,
EAGAIN should not be happening here anyway.

function                                             old     new   delta
telnetd_main                                        1798    1785     -13

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/networking/telnetd.c b/networking/telnetd.c
index 1de3abcc7..303ef1be7 100644
--- a/networking/telnetd.c
+++ b/networking/telnetd.c
@@ -192,8 +192,16 @@ 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;
         }