getty: fix handling of speed 0;

 stop using non-portable way of setting speeds.

function                                             old     new   delta
cfsetispeed                                            -      76     +76
cfsetospeed                                            -      57     +57
cfgetispeed                                            -      20     +20

1 files changed, 14 insertions, 10 deletions

diff --git a/loginutils/getty.c b/loginutils/getty.c
index 0398ea3f9..24a182ff4 100644
--- a/loginutils/getty.c
+++ b/loginutils/getty.c
@@ -165,12 +165,7 @@ static void parse_speeds(struct options *op, char *arg)
                 op->speeds[op->numspeed] = bcode(cp);
                 if (op->speeds[op->numspeed] < 0)
                         bb_error_msg_and_die("bad speed: %s", cp);
-                else if (op->speeds[op->numspeed] == 0) {
-                        struct termios tio;
-                        if (tcgetattr(1, &tio) != 0)
-                                bb_error_msg_and_die("auto baudrate detection failed");
-                        op->speeds[op->numspeed] = cfgetospeed(&tio);
-                }
+                /* note: arg "0" turns into speed B0 */
                 op->numspeed++;
                 if (op->numspeed > MAX_SPEED)
                         bb_error_msg_and_die("too many alternate speeds");
@@ -276,6 +271,7 @@ static void open_tty(const char *tty)
 /* termios_init - initialize termios settings */
 static void termios_init(struct termios *tp, int speed, struct options *op)
 {
+        speed_t ispeed, ospeed;
         /*
          * Initial termios settings: 8-bit characters, raw-mode, blocking i/o.
          * Special characters are set after we have read the login name; all
@@ -286,10 +282,18 @@ static void termios_init(struct termios *tp, int speed, struct options *op)
         /* flush input and output queues, important for modems! */
         ioctl(0, TCFLSH, TCIOFLUSH); /* tcflush(0, TCIOFLUSH)? - same */
 #endif
-
-        tp->c_cflag = CS8 | HUPCL | CREAD | speed;
+        ispeed = ospeed = speed;
+        if (speed == B0) {
+                /* Speed was specified as "0" on command line.
+                 * Just leave it unchanged */
+                ispeed = cfgetispeed(tp);
+                ospeed = cfgetospeed(tp);
+        }
+        tp->c_cflag = CS8 | HUPCL | CREAD;
         if (op->flags & F_LOCAL)
                 tp->c_cflag |= CLOCAL;
+        cfsetispeed(tp, ispeed);
+        cfsetospeed(tp, ospeed);
 
         tp->c_iflag = tp->c_lflag = tp->c_line = 0;
         tp->c_oflag = OPOST | ONLCR;
@@ -759,8 +763,8 @@ int getty_main(int argc UNUSED_PARAM, char **argv)
                                 break;
                         /* we are here only if options.numspeed > 1 */
                         baud_index = (baud_index + 1) % options.numspeed;
-                        termios.c_cflag &= ~CBAUD;
-                        termios.c_cflag |= options.speeds[baud_index];
+                        cfsetispeed(&termios, options.speeds[baud_index]);
+                        cfsetospeed(&termios, options.speeds[baud_index]);
                         tcsetattr_stdin_TCSANOW(&termios);
                 }
         }