If tmux receives a palette request (OSC 4) in a pane and the palette

entry has not been set, send a request to the most recently used client
and forward any response instead. Based on change from Tim Culverhouse
in GitHub issue 4665.

input.c

@@ -51,6 +51,20 @@
  *   be passed to the underlying terminals.
  */
 
+/* Request sent by a pane. */
+struct input_request {
+	struct client			*c;
+	struct input_ctx		*ictx;
+
+	enum input_request_type		 type;
+	int				 idx;
+	time_t				 t;
+
+	TAILQ_ENTRY(input_request)	 entry;
+	TAILQ_ENTRY(input_request)	 centry;
+};
+#define INPUT_REQUEST_TIMEOUT 5
+
 /* Input parser cell. */
 struct input_cell {
 	struct grid_cell	cell;
@@ -72,6 +86,12 @@ struct input_param {
 	};
 };
 
+/* Type of terminator. */
+enum input_end_type {
+	INPUT_END_ST,
+	INPUT_END_BEL
+};
+
 /* Input parser context. */
 struct input_ctx {
 	struct window_pane	       *wp;
@@ -80,7 +100,6 @@ struct input_ctx {
 	struct colour_palette	       *palette;
 
 	struct input_cell		cell;
-
 	struct input_cell		old_cell;
 	u_int				old_cx;
 	u_int				old_cy;
@@ -96,10 +115,7 @@ struct input_ctx {
 	u_char			       *input_buf;
 	size_t				input_len;
 	size_t				input_space;
-	enum {
+	enum input_end_type		input_end;
-		INPUT_END_ST,
-		INPUT_END_BEL
-	}			input_end;
 
 	struct input_param		param_list[24];
 	u_int				param_list_len;
@@ -110,23 +126,29 @@ struct input_ctx {
 	int				ch;
 	struct utf8_data		last;
 
+	const struct input_state       *state;
 	int				flags;
 #define INPUT_DISCARD 0x1
 #define INPUT_LAST 0x2
 
-	const struct input_state *state;
+	struct input_requests		 requests[INPUT_REQUEST_TYPES];
-
+	u_int				 request_count;
-	struct event		timer;
+	struct event			 request_timer;
 
 	/*
 	 * All input received since we were last in the ground state. Sent to
 	 * control clients on connection.
 	 */
 	struct evbuffer			*since_ground;
+	struct event			 ground_timer;
 };
 
 /* Helper functions. */
 struct input_transition;
+static void 	input_request_timer_callback(int, short, void *);
+static void	input_start_request_timer(struct input_ctx *);
+static int	input_add_request(struct input_ctx *, enum input_request_type,
+		    int);
 static int	input_split(struct input_ctx *);
 static int	input_get(struct input_ctx *, u_int, int, int);
 static void printflike(2, 3) input_reply(struct input_ctx *, const char *, ...);
@@ -766,7 +788,7 @@ input_stop_utf8(struct input_ctx *ictx)
  * long, so reset to ground.
  */
 static void
-input_timer_callback(__unused int fd, __unused short events, void *arg)
+input_ground_timer_callback(__unused int fd, __unused short events, void *arg)
 {
 	struct input_ctx	*ictx = arg;
 
@@ -776,12 +798,12 @@ input_timer_callback(__unused int fd, __unused short events, void *arg)
 
 /* Start the timer. */
 static void
-input_start_timer(struct input_ctx *ictx)
+input_start_ground_timer(struct input_ctx *ictx)
 {
 	struct timeval	tv = { .tv_sec = 5, .tv_usec = 0 };
 
-	event_del(&ictx->timer);
+	event_del(&ictx->ground_timer);
-	event_add(&ictx->timer, &tv);
+	event_add(&ictx->ground_timer, &tv);
 }
 
 /* Reset cell state to default. */
@@ -830,6 +852,7 @@ input_init(struct window_pane *wp, struct bufferevent *bev,
     struct colour_palette *palette)
 {
 	struct input_ctx	*ictx;
+	u_int			 i;
 
 	ictx = xcalloc(1, sizeof *ictx);
 	ictx->wp = wp;
@@ -842,8 +865,11 @@ input_init(struct window_pane *wp, struct bufferevent *bev,
 	ictx->since_ground = evbuffer_new();
 	if (ictx->since_ground == NULL)
 		fatalx("out of memory");
+	evtimer_set(&ictx->ground_timer, input_ground_timer_callback, ictx);
 
-	evtimer_set(&ictx->timer, input_timer_callback, ictx);
+	for (i = 0; i < INPUT_REQUEST_TYPES; i++)
+		TAILQ_INIT(&ictx->requests[i]);
+	evtimer_set(&ictx->request_timer, input_request_timer_callback, ictx);
 
 	input_reset(ictx, 0);
 	return (ictx);
@@ -853,6 +879,8 @@ input_init(struct window_pane *wp, struct bufferevent *bev,
 void
 input_free(struct input_ctx *ictx)
 {
+	struct input_request_list	*irl;
+	struct input_request		*ir, *ir1;
 	u_int				 i;
 
 	for (i = 0; i < ictx->param_list_len; i++) {
@@ -860,10 +888,21 @@ input_free(struct input_ctx *ictx)
 			free(ictx->param_list[i].str);
 	}
 
-	event_del(&ictx->timer);
+	for (i = 0; i < INPUT_REQUEST_TYPES; i++) {
+		TAILQ_FOREACH_SAFE(ir, &ictx->requests[i], entry, ir1) {
+			log_debug("%s: req %p: client %s, pane %%%u, type %d",
+			    __func__, ir, ir->c->name, ictx->wp->id, i);
+			irl = &ir->c->input_requests[i];
+			TAILQ_REMOVE(&ictx->requests[i], ir, entry);
+			TAILQ_REMOVE(&irl->requests, ir, centry);
+			free(ir);
+		}
+	}
+	event_del(&ictx->request_timer);
 
 	free(ictx->input_buf);
 	evbuffer_free(ictx->since_ground);
+	event_del(&ictx->ground_timer);
 
 	free(ictx);
 }
@@ -1122,7 +1161,7 @@ input_reply(struct input_ctx *ictx, const char *fmt, ...)
 static void
 input_clear(struct input_ctx *ictx)
 {
-	event_del(&ictx->timer);
+	event_del(&ictx->ground_timer);
 
 	*ictx->interm_buf = '\0';
 	ictx->interm_len = 0;
@@ -1142,7 +1181,7 @@ input_clear(struct input_ctx *ictx)
 static void
 input_ground(struct input_ctx *ictx)
 {
-	event_del(&ictx->timer);
+	event_del(&ictx->ground_timer);
 	evbuffer_drain(ictx->since_ground, EVBUFFER_LENGTH(ictx->since_ground));
 
 	if (ictx->input_space > INPUT_BUF_START) {
@@ -2385,7 +2424,7 @@ input_enter_dcs(struct input_ctx *ictx)
 	log_debug("%s", __func__);
 
 	input_clear(ictx);
-	input_start_timer(ictx);
+	input_start_ground_timer(ictx);
 	ictx->flags &= ~INPUT_LAST;
 }
 
@@ -2511,7 +2550,7 @@ input_enter_osc(struct input_ctx *ictx)
 	log_debug("%s", __func__);
 
 	input_clear(ictx);
-	input_start_timer(ictx);
+	input_start_ground_timer(ictx);
 	ictx->flags &= ~INPUT_LAST;
 }
 
@@ -2606,7 +2645,7 @@ input_enter_apc(struct input_ctx *ictx)
 	log_debug("%s", __func__);
 
 	input_clear(ictx);
-	input_start_timer(ictx);
+	input_start_ground_timer(ictx);
 	ictx->flags &= ~INPUT_LAST;
 }
 
@@ -2637,7 +2676,7 @@ input_enter_rename(struct input_ctx *ictx)
 	log_debug("%s", __func__);
 
 	input_clear(ictx);
-	input_start_timer(ictx);
+	input_start_ground_timer(ictx);
 	ictx->flags &= ~INPUT_LAST;
 }
 
@@ -2767,11 +2806,15 @@ input_osc_4(struct input_ctx *ictx, const char *p)
 		s = strsep(&next, ";");
 		if (strcmp(s, "?") == 0) {
 			c = colour_palette_get(palette, idx|COLOUR_FLAG_256);
-			if (c != -1)
+			if (c != -1) {
 				input_osc_colour_reply(ictx, 4, idx, c);
 				s = next;
 				continue;
 			}
+			input_add_request(ictx, INPUT_REQUEST_PALETTE, idx);
+			s = next;
+			continue;
+		}
 		if ((c = colour_parseX11(s)) == -1) {
 			s = next;
 			continue;
@@ -3110,6 +3153,143 @@ input_set_buffer_size(size_t buffer_size)
 	input_buffer_size = buffer_size;
 }
 
+/* Request timer. Remove any requests that are too old. */
+static void
+input_request_timer_callback(__unused int fd, __unused short events, void *arg)
+{
+	struct input_ctx		*ictx = arg;
+	struct input_request		*ir, *ir1;
+	struct input_request_list	*irl;
+	u_int				 i;
+	time_t				 t = time(NULL);
+
+	for (i = 0; i < INPUT_REQUEST_TYPES; i++) {
+		TAILQ_FOREACH_SAFE(ir, &ictx->requests[i], entry, ir1) {
+			if (ir->t >= t - INPUT_REQUEST_TIMEOUT)
+				continue;
+			log_debug("%s: req %p: client %s, pane %%%u, type %d",
+			    __func__, ir, ir->c->name, ictx->wp->id, ir->type);
+			irl = &ir->c->input_requests[i];
+			TAILQ_REMOVE(&ictx->requests[i], ir, entry);
+			TAILQ_REMOVE(&irl->requests, ir, centry);
+			ictx->request_count--;
+			free(ir);
+		}
+	}
+	if (ictx->request_count != 0)
+		input_start_request_timer(ictx);
+}
+
+/* Start the request timer. */
+static void
+input_start_request_timer(struct input_ctx *ictx)
+{
+	struct timeval	tv = { .tv_sec = 1, .tv_usec = 0 };
+
+	event_del(&ictx->request_timer);
+	event_add(&ictx->request_timer, &tv);
+}
+
+/* Add a request. */
+static int
+input_add_request(struct input_ctx *ictx, enum input_request_type type, int idx)
+{
+	struct window_pane	*wp = ictx->wp;
+	struct window		*w;
+	struct client		*c = NULL, *loop;
+	struct input_request	*ir;
+	char			 s[64];
+
+	if (wp == NULL)
+		return (-1);
+	w = wp->window;
+
+	TAILQ_FOREACH(loop, &clients, entry) {
+		if (loop->flags & CLIENT_UNATTACHEDFLAGS)
+			continue;
+		if (loop->session == NULL || !session_has(loop->session, w))
+			continue;
+		if (~loop->tty.flags & TTY_STARTED)
+			continue;
+		if (c == NULL)
+			c = loop;
+		else if (timercmp(&loop->activity_time, &c->activity_time, >))
+			c = loop;
+	}
+	if (c == NULL)
+		return (-1);
+
+	ir = xcalloc (1, sizeof *ir);
+	ir->c = c;
+	ir->ictx = ictx;
+	ir->type = type;
+	ir->idx = idx;
+	ir->t = time(NULL);
+	TAILQ_INSERT_TAIL(&ictx->requests[type], ir, entry);
+	TAILQ_INSERT_TAIL(&c->input_requests[type].requests, ir, centry);
+	if (++ictx->request_count == 1)
+		input_start_request_timer(ictx);
+	log_debug("%s: req %p: client %s, pane %%%u, type %d", __func__, ir,
+	    c->name, wp->id, type);
+
+	switch (type) {
+	case INPUT_REQUEST_PALETTE:
+		xsnprintf(s, sizeof s, "\033]4;%d;?\033\\", idx);
+		tty_puts(&c->tty, s);
+		break;
+	}
+
+	return (0);
+}
+
+/* Handle a reply to a request. */
+void
+input_request_reply(struct client *c, enum input_request_type type, void *data)
+{
+	struct input_request_list		*irl = &c->input_requests[type];
+	struct input_request			*ir, *ir1;
+	struct input_request_palette_data	*pd = data;
+
+	TAILQ_FOREACH_SAFE(ir, &irl->requests, centry, ir1) {
+		log_debug("%s: req %p: client %s, pane %%%u, type %d",
+		    __func__, ir, c->name, ir->ictx->wp->id, ir->type);
+		switch (type) {
+		case INPUT_REQUEST_PALETTE:
+			if (pd->idx != ir->idx)
+				continue;
+			input_osc_colour_reply(ir->ictx, 4, pd->idx, pd->c);
+			break;
+		}
+		TAILQ_REMOVE(&ir->ictx->requests[type], ir, entry);
+		TAILQ_REMOVE(&irl->requests, ir, centry);
+		ir->ictx->request_count--;
+		free(ir);
+		break;
+	}
+}
+
+/* Cancel pending requests for client. */
+void
+input_cancel_requests(struct client *c)
+{
+	struct input_request_list	*irl;
+	struct input_request		*ir, *ir1;
+	u_int				 i;
+
+	for (i = 0; i < INPUT_REQUEST_TYPES; i++) {
+		irl = &c->input_requests[i];
+		TAILQ_FOREACH_SAFE(ir, &irl->requests, entry, ir1) {
+			log_debug("%s: req %p: client %s, pane %%%u, type %d",
+			    __func__, ir, c->name, ir->ictx->wp->id, ir->type);
+			TAILQ_REMOVE(&ir->ictx->requests[i], ir, entry);
+			TAILQ_REMOVE(&irl->requests, ir, centry);
+			ir->ictx->request_count--;
+			free(ir);
+		}
+	}
+}
+
+/* Report current theme. */
 static void
 input_report_current_theme(struct input_ctx *ictx)
 {

server-client.c

@@ -282,6 +282,7 @@ struct client *
 server_client_create(int fd)
 {
 	struct client	*c;
+	u_int		 i;
 
 	setblocking(fd, 0);
 
@@ -315,6 +316,12 @@ server_client_create(int fd)
 	evtimer_set(&c->repeat_timer, server_client_repeat_timer, c);
 	evtimer_set(&c->click_timer, server_client_click_timer, c);
 
+	for (i = 0; i < INPUT_REQUEST_TYPES; i++) {
+		c->input_requests[i].c = c;
+		c->input_requests[i].type = i;
+		TAILQ_INIT(&c->input_requests[i].requests);
+	}
+
 	TAILQ_INSERT_TAIL(&clients, c, entry);
 	log_debug("new client %p", c);
 	return (c);
@@ -463,6 +470,7 @@ server_client_lost(struct client *c)
 	tty_term_free_list(c->term_caps, c->term_ncaps);
 
 	status_free(c);
+	input_cancel_requests(c);
 
 	free(c->title);
 	free((void *)c->cwd);

tmux.h

@@ -53,6 +53,8 @@ struct format_tree;
 struct hyperlinks_uri;
 struct hyperlinks;
 struct input_ctx;
+struct input_request;
+struct input_requests;
 struct job;
 struct menu_data;
 struct mode_tree_data;
@@ -1092,6 +1094,26 @@ struct window_mode_entry {
 	TAILQ_ENTRY(window_mode_entry)	 entry;
 };
 
+/* Type of request to client. */
+enum input_request_type {
+	INPUT_REQUEST_PALETTE
+};
+#define INPUT_REQUEST_TYPES (1)
+
+/* Palette request reply data. */
+struct input_request_palette_data {
+	int	idx;
+	int	c;
+};
+
+/* Request sent to client on behalf of pane. */
+TAILQ_HEAD(input_requests, input_request);
+struct input_request_list {
+	struct client	       *c;
+	enum input_request_type	type;
+	struct input_requests	requests;
+};
+
 /* Offsets into pane buffer. */
 struct window_pane_offset {
 	size_t	used;
@@ -1920,6 +1942,8 @@ struct client {
 	struct status_line	 status;
 	enum client_theme	 theme;
 
+	struct input_request_list input_requests[INPUT_REQUEST_TYPES];
+
 #define CLIENT_TERMINAL 0x1
 #define CLIENT_LOGIN 0x2
 #define CLIENT_EXIT 0x4
@@ -2922,6 +2946,8 @@ void	 input_parse_screen(struct input_ctx *, struct screen *,
 void	 input_reply_clipboard(struct bufferevent *, const char *, size_t,
 	     const char *);
 void	 input_set_buffer_size(size_t);
+void	 input_request_reply(struct client *, enum input_request_type, void *);
+void	 input_cancel_requests(struct client *);
 
 /* input-key.c */
 void	 input_key_build(void);

tty-keys.c

@@ -59,6 +59,7 @@ static int	tty_keys_device_attributes2(struct tty *, const char *, size_t,
 		    size_t *);
 static int	tty_keys_extended_device_attributes(struct tty *, const char *,
 		    size_t, size_t *);
+static int	tty_keys_palette(struct tty *, const char *, size_t, size_t *);
 
 /* A key tree entry. */
 struct tty_key {
@@ -804,6 +805,17 @@ tty_keys_next(struct tty *tty)
 		goto partial_key;
 	}
 
+	/* Is this a palette response? */
+	switch (tty_keys_palette(tty, buf, len, &size)) {
+	case 0:		/* yes */
+		key = KEYC_UNKNOWN;
+		goto complete_key;
+	case -1:	/* no, or not valid */
+		break;
+	case 1:		/* partial */
+		goto partial_key;
+	}
+
 	/* Is this a mouse key press? */
 	switch (tty_keys_mouse(tty, buf, len, &size, &m)) {
 	case 0:		/* yes */
@@ -1699,3 +1711,67 @@ tty_keys_colours(struct tty *tty, const char *buf, size_t len, size_t *size,
 
 	return (0);
 }
+
+/* Handle OSC 4 palette colour responses. */
+static int
+tty_keys_palette(struct tty *tty, const char *buf, size_t len, size_t *size)
+{
+	struct client			 *c = tty->client;
+	u_int				  i, start;
+	char				  tmp[128], *endptr;
+	int				  idx;
+	struct input_request_palette_data pd;
+
+	*size = 0;
+
+	/* First three bytes are always \033]4. */
+	if (buf[0] != '\033')
+		return (-1);
+	if (len == 1)
+		return (1);
+	if (buf[1] != ']')
+		return (-1);
+	if (len == 2)
+		return (1);
+	if (buf[2] != '4')
+		return (-1);
+	if (len == 3)
+		return (1);
+	if (buf[3] != ';')
+		return (-1);
+	if (len == 4)
+		return (1);
+
+	/* Parse index. */
+	idx = strtol(buf + 4, &endptr, 10);
+	if (endptr == buf + 4 || *endptr != ';')
+		return (-1);
+	if (idx < 0 || idx > 255)
+		return (-1);
+
+	/* Copy the rest up to \033\ or \007. */
+	start = (endptr - buf) + 1;
+	for (i = start; i < len && i - start < sizeof tmp; i++) {
+		if (buf[i - 1] == '\033' && buf[i] == '\\')
+			break;
+		if (buf[i] == '\007')
+			break;
+		tmp[i - start] = buf[i];
+	}
+	if (i - start == sizeof tmp)
+		return (-1);
+	if (i > 0 && buf[i - 1] == '\033')
+		tmp[i - start - 1] = '\0';
+	else
+		tmp[i - start] = '\0';
+	*size = i + 1;
+
+	/* Work out the colour. */
+	pd.c = colour_parseX11(tmp);
+	if (pd.c == -1)
+		return (0);
+	pd.idx = idx;
+	input_request_reply(c, INPUT_REQUEST_PALETTE, &pd);
+
+	return (0);
+}

tty.c

@@ -414,10 +414,12 @@ tty_repeat_requests(struct tty *tty, int force)
 		return;
 
 	if (!force && n <= TTY_REQUEST_LIMIT) {
-		log_debug("%s: not repeating requests (%u seconds)", c->name, n);
+		log_debug("%s: not repeating requests (%u seconds)", c->name,
+		    n);
 		return;
 	}
-	log_debug("%s: %srepeating requests (%u seconds)", c->name, force ? "(force) " : "" , n);
+	log_debug("%s: %srepeating requests (%u seconds)", c->name,
+	    force ? "(force) " : "" , n);
 	tty->last_requests = t;
 
 	if (tty->term->flags & TERM_VT100LIKE) {