clients/cli: use a nicer password prompt

Makes sense in order for the user to know that they're actually typing
the password (edited just to illustrate the point, the actual output was
shamefully messy and perhaps needs fixing too):

  $ nmcli c up Wrathmosphere
  Passwords or encryption keys are required to access the wireless network 'Wrathmosphere'.
  Password (802-1x.password): *********

1 files changed, 30 insertions, 12 deletions

diff --git a/clients/cli/common.c b/clients/cli/common.c
index 4c15463d34..3689defeb1 100644
--- a/clients/cli/common.c
+++ b/clients/cli/common.c
@@ -16,7 +16,7 @@
  * with this program; if not, write to the Free Software Foundation, Inc.,
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  *
- * Copyright 2012 - 2014 Red Hat, Inc.
+ * Copyright 2012 - 2017 Red Hat, Inc.
  */
 
 #include "nm-default.h"
@@ -26,7 +26,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <errno.h>
-#include <termios.h>
 #include <sys/ioctl.h>
 #include <readline/readline.h>
 #include <readline/history.h>
@@ -880,6 +879,31 @@ nmc_readline (const char *prompt_fmt, ...)
 	return str;
 }
 
+static void
+nmc_secret_redisplay (void)
+{
+	int save_point = rl_point;
+	int save_end = rl_end;
+	char *save_line_buffer = rl_line_buffer;
+	const char *subst = nmc_password_subst_char ();
+	int subst_len = strlen (subst);
+	int i;
+
+	rl_point = g_utf8_strlen (save_line_buffer, save_point) * subst_len;
+	rl_end = g_utf8_strlen (rl_line_buffer, -1) * subst_len;
+	rl_line_buffer = g_slice_alloc (rl_end + 1);
+
+	for (i = 0; i + subst_len <= rl_end; i += subst_len)
+		memcpy (&rl_line_buffer[i], subst, subst_len);
+	rl_line_buffer[i] = '\0';
+
+	rl_redisplay ();
+	g_slice_free1 (rl_end + 1, rl_line_buffer);
+	rl_line_buffer = save_line_buffer;
+	rl_end = save_end;
+	rl_point = save_point;
+}
+
 /**
  * nmc_readline_echo:
  *
@@ -891,7 +915,6 @@ nmc_readline_echo (gboolean echo_on, const char *prompt_fmt, ...)
 {
 	va_list args;
 	char *prompt, *str;
-	struct termios termios_orig, termios_new;
 	HISTORY_STATE *saved_history;
 	HISTORY_STATE passwd_history = { 0, };
 
@@ -899,25 +922,20 @@ nmc_readline_echo (gboolean echo_on, const char *prompt_fmt, ...)
 	prompt = g_strdup_vprintf (prompt_fmt, args);
 	va_end (args);
 
-	/* Disable echoing characters */
+	/* Hide the actual password */
 	if (!echo_on) {
 		saved_history = history_get_history_state ();
 		history_set_history_state (&passwd_history);
-		tcgetattr (STDIN_FILENO, &termios_orig);
-		termios_new = termios_orig;
-		termios_new.c_lflag &= ~(ECHO);
-		tcsetattr (STDIN_FILENO, TCSADRAIN, &termios_new);
+		rl_redisplay_function = nmc_secret_redisplay;
 	}
 
 	str = nmc_readline_helper (prompt);
 
 	g_free (prompt);
 
-	/* Restore original terminal settings */
+	/* Restore the non-hiding behavior */
 	if (!echo_on) {
-		tcsetattr (STDIN_FILENO, TCSADRAIN, &termios_orig);
-		/* New line - setting ECHONL | ICANON did not help */
-		fprintf (stdout, "\n");
+		rl_redisplay_function = rl_redisplay;
 		history_set_history_state (saved_history);
 	}