terminal-util: add helper for disabling terminal echo in termios struct

src/basic/terminal-util.c

@@ -1551,3 +1551,11 @@ int set_terminal_cursor_position(int fd, unsigned int row, unsigned int column)
 
         return 0;
 }
+
+void termios_disable_echo(struct termios *termios) {
+        assert(termios);
+
+        termios->c_lflag &= ~(ICANON|ECHO);
+        termios->c_cc[VMIN] = 1;
+        termios->c_cc[VTIME] = 0;
+}

src/basic/terminal-util.h

@@ -6,6 +6,7 @@
 #include <stdio.h>
 #include <syslog.h>
 #include <sys/types.h>
+#include <termios.h>
 
 #include "macro.h"
 #include "time-util.h"
@@ -168,7 +169,6 @@ bool underline_enabled(void);
 bool dev_console_colors_enabled(void);
 
 static inline bool colors_enabled(void) {
-
         /* Returns true if colors are considered supported on our stdout. */
         return get_color_mode() != COLOR_OFF;
 }
@@ -286,3 +286,5 @@ static inline const char* ansi_highlight_green_red(bool b) {
 
 /* This assumes there is a 'tty' group */
 #define TTY_MODE 0620
+
+void termios_disable_echo(struct termios *termios);