Separate "very visible" flag from blinking flag, it should not affect

DECSCUSR. GitHub issue 2891.

input.c

@@ -1646,7 +1646,7 @@ input_csi_dispatch_rm(struct input_ctx *ictx)
 			screen_write_mode_clear(sctx, MODE_INSERT);
 			break;
 		case 34:
-			screen_write_mode_set(sctx, MODE_BLINKING);
+			screen_write_mode_set(sctx, MODE_CURSOR_VERY_VISIBLE);
 			break;
 		default:
 			log_debug("%s: unknown '%c'", __func__, ictx->ch);
@@ -1682,7 +1682,7 @@ input_csi_dispatch_rm_private(struct input_ctx *ictx)
 			screen_write_mode_clear(sctx, MODE_WRAP);
 			break;
 		case 12:
-			screen_write_mode_clear(sctx, MODE_BLINKING);
+			screen_write_mode_clear(sctx, MODE_CURSOR_BLINKING);
 			break;
 		case 25:	/* TCEM */
 			screen_write_mode_clear(sctx, MODE_CURSOR);
@@ -1734,7 +1734,7 @@ input_csi_dispatch_sm(struct input_ctx *ictx)
 			screen_write_mode_set(sctx, MODE_INSERT);
 			break;
 		case 34:
-			screen_write_mode_clear(sctx, MODE_BLINKING);
+			screen_write_mode_clear(sctx, MODE_CURSOR_VERY_VISIBLE);
 			break;
 		default:
 			log_debug("%s: unknown '%c'", __func__, ictx->ch);
@@ -1771,7 +1771,7 @@ input_csi_dispatch_sm_private(struct input_ctx *ictx)
 			screen_write_mode_set(sctx, MODE_WRAP);
 			break;
 		case 12:
-			screen_write_mode_set(sctx, MODE_BLINKING);
+			screen_write_mode_set(sctx, MODE_CURSOR_BLINKING);
 			break;
 		case 25:	/* TCEM */
 			screen_write_mode_set(sctx, MODE_CURSOR);

screen.c

@@ -163,27 +163,27 @@ screen_set_cursor_style(struct screen *s, u_int style)
 		break;
 	case 1:
 		s->cstyle = SCREEN_CURSOR_BLOCK;
-		s->mode |= MODE_BLINKING;
+		s->mode |= MODE_CURSOR_BLINKING;
 		break;
 	case 2:
 		s->cstyle = SCREEN_CURSOR_BLOCK;
-		s->mode &= ~MODE_BLINKING;
+		s->mode &= ~MODE_CURSOR_BLINKING;
 		break;
 	case 3:
 		s->cstyle = SCREEN_CURSOR_UNDERLINE;
-		s->mode |= MODE_BLINKING;
+		s->mode |= MODE_CURSOR_BLINKING;
 		break;
 	case 4:
 		s->cstyle = SCREEN_CURSOR_UNDERLINE;
-		s->mode &= ~MODE_BLINKING;
+		s->mode &= ~MODE_CURSOR_BLINKING;
 		break;
 	case 5:
 		s->cstyle = SCREEN_CURSOR_BAR;
-		s->mode |= MODE_BLINKING;
+		s->mode |= MODE_CURSOR_BLINKING;
 		break;
 	case 6:
 		s->cstyle = SCREEN_CURSOR_BAR;
-		s->mode &= ~MODE_BLINKING;
+		s->mode &= ~MODE_CURSOR_BLINKING;
 		break;
 	}
 }
@@ -680,8 +680,10 @@ screen_mode_to_string(int mode)
 		strlcat(tmp, "MOUSE_STANDARD,", sizeof tmp);
 	if (mode & MODE_MOUSE_BUTTON)
 		strlcat(tmp, "MOUSE_BUTTON,", sizeof tmp);
-	if (mode & MODE_BLINKING)
+	if (mode & MODE_CURSOR_BLINKING)
-		strlcat(tmp, "BLINKING,", sizeof tmp);
+		strlcat(tmp, "CURSOR_BLINKING,", sizeof tmp);
+	if (mode & MODE_CURSOR_VERY_VISIBLE)
+		strlcat(tmp, "CURSOR_VERY_VISIBLE,", sizeof tmp);
 	if (mode & MODE_MOUSE_UTF8)
 		strlcat(tmp, "UTF8,", sizeof tmp);
 	if (mode & MODE_MOUSE_SGR)

tmux.h

@@ -520,7 +520,7 @@ enum tty_code_code {
 #define MODE_WRAP 0x10
 #define MODE_MOUSE_STANDARD 0x20
 #define MODE_MOUSE_BUTTON 0x40
-#define MODE_BLINKING 0x80
+#define MODE_CURSOR_BLINKING 0x80
 #define MODE_MOUSE_UTF8 0x100
 #define MODE_MOUSE_SGR 0x200
 #define MODE_BRACKETPASTE 0x400
@@ -529,10 +529,12 @@ enum tty_code_code {
 #define MODE_ORIGIN 0x2000
 #define MODE_CRLF 0x4000
 #define MODE_KEXTENDED 0x8000
+#define MODE_CURSOR_VERY_VISIBLE 0x10000
 
 #define ALL_MODES 0xffffff
 #define ALL_MOUSE_MODES (MODE_MOUSE_STANDARD|MODE_MOUSE_BUTTON|MODE_MOUSE_ALL)
 #define MOTION_MOUSE_MODES (MODE_MOUSE_BUTTON|MODE_MOUSE_ALL)
+#define CURSOR_MODES (MODE_CURSOR|MODE_CURSOR_BLINKING|MODE_CURSOR_VERY_VISIBLE)
 
 /* A single UTF-8 character. */
 typedef u_int utf8_char;

tty.c

@@ -314,7 +314,7 @@ tty_start_tty(struct tty *tty)
 	tio.c_cc[VMIN] = 1;
 	tio.c_cc[VTIME] = 0;
 	if (tcsetattr(c->fd, TCSANOW, &tio) == 0)
-		tcflush(c->fd, TCIOFLUSH);
+		tcflush(c->fd, TCOFLUSH);
 
 	tty_putcode(tty, TTYC_SMCUP);
 
@@ -658,12 +658,83 @@ tty_force_cursor_colour(struct tty *tty, const char *ccolour)
 	tty->ccolour = xstrdup(ccolour);
 }
 
+static void
+tty_update_cursor(struct tty *tty, int mode, int changed, struct screen *s)
+{
+	enum screen_cursor_style cstyle;
+
+	/* Set cursor colour if changed. */
+	if (s != NULL && strcmp(s->ccolour, tty->ccolour) != 0)
+		tty_force_cursor_colour(tty, s->ccolour);
+
+	/* If cursor is off, set as invisible. */
+	if (~mode & MODE_CURSOR) {
+		if (changed & MODE_CURSOR)
+			tty_putcode(tty, TTYC_CIVIS);
+		return;
+	}
+
+	/* Check if blinking or very visible flag changed or style changed. */
+	if (s == NULL)
+		cstyle = tty->cstyle;
+	else
+		cstyle = s->cstyle;
+	if ((changed & CURSOR_MODES) == 0 && cstyle == tty->cstyle)
+		return;
+
+	/*
+	 * Set cursor style. If an explicit style has been set with DECSCUSR,
+	 * set it if supported, otherwise send cvvis for blinking styles.
+	 *
+	 * If no style, has been set (SCREEN_CURSOR_DEFAULT), then send cvvis
+	 * if either the blinking or very visible flags are set.
+	 */
+	tty_putcode(tty, TTYC_CNORM);
+	switch (cstyle) {
+	case SCREEN_CURSOR_DEFAULT:
+		if (tty_term_has(tty->term, TTYC_SE))
+			tty_putcode(tty, TTYC_SE);
+		else
+			tty_putcode1(tty, TTYC_SS, 0);
+		if (mode & (MODE_CURSOR_BLINKING|MODE_CURSOR_VERY_VISIBLE))
+			tty_putcode(tty, TTYC_CVVIS);
+		break;
+	case SCREEN_CURSOR_BLOCK:
+		if (tty_term_has(tty->term, TTYC_SS)) {
+			if (mode & MODE_CURSOR_BLINKING)
+				tty_putcode1(tty, TTYC_SS, 1);
+			else
+				tty_putcode1(tty, TTYC_SS, 2);
+		} else if (mode & MODE_CURSOR_BLINKING)
+			tty_putcode(tty, TTYC_CVVIS);
+		break;
+	case SCREEN_CURSOR_UNDERLINE:
+		if (tty_term_has(tty->term, TTYC_SS)) {
+			if (mode & MODE_CURSOR_BLINKING)
+				tty_putcode1(tty, TTYC_SS, 3);
+			else
+				tty_putcode1(tty, TTYC_SS, 4);
+		} else if (mode & MODE_CURSOR_BLINKING)
+			tty_putcode(tty, TTYC_CVVIS);
+		break;
+	case SCREEN_CURSOR_BAR:
+		if (tty_term_has(tty->term, TTYC_SS)) {
+			if (mode & MODE_CURSOR_BLINKING)
+				tty_putcode1(tty, TTYC_SS, 5);
+			else
+				tty_putcode1(tty, TTYC_SS, 6);
+		} else if (mode & MODE_CURSOR_BLINKING)
+			tty_putcode(tty, TTYC_CVVIS);
+		break;
+	}
+	tty->cstyle = cstyle;
+ }
+
 void
 tty_update_mode(struct tty *tty, int mode, struct screen *s)
 {
 	struct client	*c = tty->client;
 	int		 changed;
-	enum screen_cursor_style cstyle = tty->cstyle;
 
 	if (tty->flags & TTY_NOCURSOR)
 		mode &= ~MODE_CURSOR;
@@ -676,85 +747,7 @@ tty_update_mode(struct tty *tty, int mode, struct screen *s)
 		    screen_mode_to_string(mode));
 	}
 
-	if (s != NULL) {
+	tty_update_cursor(tty, mode, changed, s);
-		if (strcmp(s->ccolour, tty->ccolour) != 0)
-			tty_force_cursor_colour(tty, s->ccolour);
-		cstyle = s->cstyle;
-	}
-	if (~mode & MODE_CURSOR) {
-		/* Cursor now off - set as invisible. */
-		if (changed & MODE_CURSOR)
-			tty_putcode(tty, TTYC_CIVIS);
-	} else if ((changed & (MODE_CURSOR|MODE_BLINKING)) ||
-	    cstyle != tty->cstyle) {
-		/*
-		 * Cursor now on, blinking flag changed or style changed. Start
-		 * by setting the cursor to normal.
-		 */
-		tty_putcode(tty, TTYC_CNORM);
-		switch (cstyle) {
-		case SCREEN_CURSOR_DEFAULT:
-			/*
-			 * If the old style wasn't default, then reset it to
-			 * default.
-			 */
-			if (tty->cstyle != SCREEN_CURSOR_DEFAULT) {
-				if (tty_term_has(tty->term, TTYC_SE))
-					tty_putcode(tty, TTYC_SE);
-				else
-					tty_putcode1(tty, TTYC_SS, 0);
-			}
-
-			/* Set the cursor as very visible if necessary. */
-			if (mode & MODE_BLINKING)
-				tty_putcode(tty, TTYC_CVVIS);
-			break;
-		case SCREEN_CURSOR_BLOCK:
-			/*
-			 * Set style to either block blinking (1) or steady (2)
-			 * if supported, otherwise just check the blinking
-			 * flag.
-			 */
-			if (tty_term_has(tty->term, TTYC_SS)) {
-				if (mode & MODE_BLINKING)
-					tty_putcode1(tty, TTYC_SS, 1);
-				else
-					tty_putcode1(tty, TTYC_SS, 2);
-			} else if (mode & MODE_BLINKING)
-				tty_putcode(tty, TTYC_CVVIS);
-			break;
-		case SCREEN_CURSOR_UNDERLINE:
-			/*
-			 * Set style to either underline blinking (3) or steady
-			 * (4) if supported, otherwise just check the blinking
-			 * flag.
-			 */
-			if (tty_term_has(tty->term, TTYC_SS)) {
-				if (mode & MODE_BLINKING)
-					tty_putcode1(tty, TTYC_SS, 3);
-				else
-					tty_putcode1(tty, TTYC_SS, 4);
-			} else if (mode & MODE_BLINKING)
-				tty_putcode(tty, TTYC_CVVIS);
-			break;
-		case SCREEN_CURSOR_BAR:
-			/*
-			 * Set style to either bar blinking (5) or steady (6)
-			 * if supported, otherwise just check the blinking
-			 * flag.
-			 */
-			if (tty_term_has(tty->term, TTYC_SS)) {
-				if (mode & MODE_BLINKING)
-					tty_putcode1(tty, TTYC_SS, 5);
-				else
-					tty_putcode1(tty, TTYC_SS, 6);
-			} else if (mode & MODE_BLINKING)
-				tty_putcode(tty, TTYC_CVVIS);
-			break;
-		}
-		tty->cstyle = cstyle;
-	}
-
 	if ((changed & ALL_MOUSE_MODES) &&
 	    tty_term_has(tty->term, TTYC_KMOUS)) {
 		/*