Fix #84: Reset TTY w/ stty() before taking any pre-getty action

This patch moves the stty() function from getty.c to a separate file so
it can be called from exec.c as well.  The fix to #84 is simply to call
stty() in prepare_tty(), which is shared by run_getty() and run_getty2()
and called before "Please press Enter ...".

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

src/stty.c

@@ -0,0 +1,69 @@
+/* Reset terminal line settings (stty sane)
+ *
+ * Copyright (c) 2016-2017  Joachim Nilsson <troglobit@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <unistd.h>	      /* _POSIX_VDISABLE */
+#include <sys/ttydefaults.h>  /* Not included by default in musl libc */
+#include <termios.h>
+
+void stty(int fd, speed_t speed)
+{
+	struct termios term;
+
+	tcdrain(fd);
+	if (tcgetattr(fd, &term))
+		return;
+
+	cfsetispeed(&term, speed);
+	cfsetospeed(&term, speed);
+	tcsetattr(fd, TCSAFLUSH, &term);
+	tcflush(fd, TCIOFLUSH);
+
+	/* Disable modem specific flags */
+	term.c_cflag     &= ~(0|CSTOPB|PARENB|PARODD);
+	term.c_cflag     &= ~CRTSCTS;
+	term.c_cflag     |= CLOCAL;
+
+	/* Timeouts, minimum chars and default flags */
+	term.c_cc[VTIME]  = 0;
+	term.c_cc[VMIN]   = 1;
+	term.c_iflag      = ICRNL|IXON|IXOFF;
+	term.c_oflag      = OPOST|ONLCR;
+	term.c_cflag     |= CS8|CREAD|HUPCL|CBAUDEX;
+	term.c_lflag     |= ICANON|ISIG|ECHO|ECHOE|ECHOK|ECHOKE;
+
+	/* Reset special characters to defaults */
+	term.c_cc[VINTR]  = CTRL('C');
+	term.c_cc[VQUIT]  = CTRL('\\');
+	term.c_cc[VEOF]   = CTRL('D');
+	term.c_cc[VEOL]   = '\n';
+	term.c_cc[VKILL]  = CTRL('U');
+	term.c_cc[VERASE] = CERASE;
+	tcsetattr(fd, TCSANOW, &term);
+}
+
+/**
+ * Local Variables:
+ *  indent-tabs-mode: t
+ *  c-file-style: "linux"
+ * End:
+ */