Support DECSCUSR sequence to set the cursor style with two new

terminfo(5) extensions, Cs and Csr. Written by Ailin Nemui.

input.c

@@ -126,6 +126,7 @@ enum input_csi_type {
 	INPUT_CSI_CUU,
 	INPUT_CSI_DA,
 	INPUT_CSI_DCH,
+	INPUT_CSI_DECSCUSR,
 	INPUT_CSI_DECSTBM,
 	INPUT_CSI_DL,
 	INPUT_CSI_DSR,
@@ -168,6 +169,7 @@ const struct input_table_entry input_csi_table[] = {
 	{ 'l', "?", INPUT_CSI_RM_PRIVATE },
 	{ 'm', "",  INPUT_CSI_SGR },
 	{ 'n', "",  INPUT_CSI_DSR },
+	{ 'q', " ", INPUT_CSI_DECSCUSR },
 	{ 'r', "",  INPUT_CSI_DECSTBM },
 };
 
@@ -1259,6 +1261,10 @@ input_csi_dispatch(struct input_ctx *ictx)
 		n = input_get(ictx, 0, 1, 1);
 		screen_write_cursormove(sctx, s->cx, n - 1);
 		break;
+	case INPUT_CSI_DECSCUSR:
+		n = input_get(ictx, 0, 0, 0);
+		screen_set_cursor_style(s, n);
+		break;
 	}
 
 	return (0);

options-table.c

@@ -368,6 +368,7 @@ const struct options_table_entry session_options_table[] = {
 	  .default_str = "*88col*:colors=88,*256col*:colors=256"
 	                 ",xterm*:XT:Ms=\\E]52;%p1%s;%p2%s\\007"
 	                 ":Cc=\\E]12;%p1%s\\007:Cr=\\E]112\\007"
+			 ":Cs=\\E[%p1%d q:Csr=\\E[2 q"
 	},
 
 	{ .name = "update-environment",

screen.c

@@ -40,6 +40,7 @@ screen_init(struct screen *s, u_int sx, u_int sy, u_int hlimit)
 	else
 		s->title = xstrdup("");
 
+	s->cstyle = 0;
 	s->ccolour = xstrdup("");
 	s->tabs = NULL;
 
@@ -91,6 +92,14 @@ screen_reset_tabs(struct screen *s)
 		bit_set(s->tabs, i);
 }
 
+/* Set screen cursor style. */
+void
+screen_set_cursor_style(struct screen *s, u_int style)
+{
+	if (style <= 4)
+		s->cstyle = style;
+}
+
 /* Set screen cursor colour. */
 void
 screen_set_cursor_colour(struct screen *s, const char *colour_string)

tmux.1

@@ -2832,6 +2832,19 @@ See the
 option above and the
 .Xr xterm 1
 man page.
+.It Em Cs, Csr
+Change the cursor style.
+If set allows a sequence such as:
+.Bd -literal -offset indent
+$ printf '\e033[4 q'
+.Ed
+.Pp
+To change the cursor to an underline.
+If
+.Em Csr
+is set, it will be used to reset the cursor style instead
+of
+.Em Cs .
 .It Em Cc, Cr
 The first takes one string argument and is used to set the cursor colour;
 the second takes no arguments and restores the default cursor colour.

tmux.h

@@ -189,7 +189,9 @@ enum tty_code_code {
 	TTYC_CNORM,	/* cursor_normal, ve */
 	TTYC_COLORS,	/* max_colors, Co */
 	TTYC_CR,	/* restore cursor colour, Cr */
+	TTYC_CS1,	/* set cursor style, Cs */
 	TTYC_CSR,	/* change_scroll_region, cs */
+	TTYC_CSR1,	/* reset cursor style, Csr */
 	TTYC_CUB,	/* parm_left_cursor, LE */
 	TTYC_CUB1,	/* cursor_left, le */
 	TTYC_CUD,	/* parm_down_cursor, DO */
@@ -716,6 +718,7 @@ struct screen {
 	u_int		 cx;		/* cursor x */
 	u_int		 cy;		/* cursor y */
 
+	u_int		 cstyle;	/* cursor style */
 	char		*ccolour;	/* cursor colour string */
 
 	u_int		 rupper;	/* scroll region top */
@@ -1014,6 +1017,7 @@ struct tty {
 
 	u_int		 cx;
 	u_int		 cy;
+	u_int		 cstyle;
 	char		*ccolour;
 
 	int		 mode;
@@ -1850,6 +1854,7 @@ void	 screen_init(struct screen *, u_int, u_int, u_int);
 void	 screen_reinit(struct screen *);
 void	 screen_free(struct screen *);
 void	 screen_reset_tabs(struct screen *);
+void	 screen_set_cursor_style(struct screen *, u_int);
 void	 screen_set_cursor_colour(struct screen *, const char *);
 void	 screen_set_title(struct screen *, const char *);
 void	 screen_resize(struct screen *, u_int, u_int);

tty-term.c

@@ -44,7 +44,9 @@ const struct tty_term_code_entry tty_term_codes[NTTYCODE] = {
 	{ TTYC_CNORM, TTYCODE_STRING, "cnorm" },
 	{ TTYC_COLORS, TTYCODE_NUMBER, "colors" },
 	{ TTYC_CR, TTYCODE_STRING, "Cr" },
+	{ TTYC_CS1, TTYCODE_STRING, "Cs" },
 	{ TTYC_CSR, TTYCODE_STRING, "csr" },
+	{ TTYC_CSR1, TTYCODE_STRING, "Csr" },
 	{ TTYC_CUB, TTYCODE_STRING, "cub" },
 	{ TTYC_CUB1, TTYCODE_STRING, "cub1" },
 	{ TTYC_CUD, TTYCODE_STRING, "cud" },

tty.c

@@ -69,6 +69,7 @@ tty_init(struct tty *tty, int fd, char *term)
 	if ((path = ttyname(fd)) == NULL)
 		fatalx("ttyname failed");
 	tty->path = xstrdup(path);
+	tty->cstyle = 0;
 	tty->ccolour = xstrdup("");
 
 	tty->flags = 0;
@@ -244,6 +245,12 @@ tty_stop_tty(struct tty *tty)
 	tty_raw(tty, tty_term_string(tty->term, TTYC_SGR0));
 	tty_raw(tty, tty_term_string(tty->term, TTYC_RMKX));
 	tty_raw(tty, tty_term_string(tty->term, TTYC_CLEAR));
+	if (tty_term_has(tty->term, TTYC_CS1) && tty->cstyle != 0) {
+		if (tty_term_has(tty->term, TTYC_CSR1))
+			tty_raw(tty, tty_term_string(tty->term, TTYC_CSR1));
+		else if (tty_term_has(tty->term, TTYC_CS1))
+			tty_raw(tty, tty_term_string1(tty->term, TTYC_CS1, 0));
+	}
 	tty_raw(tty, tty_term_string(tty->term, TTYC_CR));
 
 	tty_raw(tty, tty_term_string(tty->term, TTYC_CNORM));
@@ -429,6 +436,16 @@ tty_update_mode(struct tty *tty, int mode, struct screen *s)
 		else
 			tty_putcode(tty, TTYC_CIVIS);
 	}
+	if (tty->cstyle != s->cstyle) {
+		if (tty_term_has(tty->term, TTYC_CS1)) {
+			if (s->cstyle == 0 &&
+			    tty_term_has(tty->term, TTYC_CSR1))
+				tty_putcode(tty, TTYC_CSR1);
+			else
+				tty_putcode1(tty, TTYC_CS1, s->cstyle);
+		}
+		tty->cstyle = s->cstyle;
+	}
 	if (changed & ALL_MOUSE_MODES) {
 		if (mode & ALL_MOUSE_MODES) {
 			if (mode & MODE_MOUSE_UTF8)