Add an option to control the input buffer size, from Ken Lau.

input.c

@@ -93,7 +93,6 @@ struct input_ctx {
 	size_t			param_len;
 
 #define INPUT_BUF_START 32
-#define INPUT_BUF_LIMIT 1048576
 	u_char		       *input_buf;
 	size_t			input_len;
 	size_t			input_space;
@@ -729,6 +728,9 @@ static const struct input_transition input_state_consume_st_table[] = {
 	{ -1, -1, NULL, NULL }
 };
 
+/* Maximum of bytes allowed to read in a single input. */
+static size_t input_buffer_size = INPUT_BUF_DEFAULT_SIZE;
+
 /* Input table compare. */
 static int
 input_table_compare(const void *key, const void *value)
@@ -1193,7 +1195,7 @@ input_input(struct input_ctx *ictx)
 	available = ictx->input_space;
 	while (ictx->input_len + 1 >= available) {
 		available *= 2;
-		if (available > INPUT_BUF_LIMIT) {
+		if (available > input_buffer_size) {
 			ictx->flags |= INPUT_DISCARD;
 			return (0);
 		}
@@ -3017,3 +3019,11 @@ input_reply_clipboard(struct bufferevent *bev, const char *buf, size_t len,
 	bufferevent_write(bev, end, strlen(end));
 	free(out);
 }
+
+/* Set input buffer size. */
+void
+input_set_buffer_size(size_t buffer_size)
+{
+	log_debug("%s: %lu -> %lu", __func__, input_buffer_size, buffer_size);
+	input_buffer_size = buffer_size;
+}

options-table.c

@@ -348,6 +348,15 @@ const struct options_table_entry options_table[] = {
 		  "Empty does not write a history file."
 	},
 
+	{ .name = "input-buffer-size",
+	  .type = OPTIONS_TABLE_NUMBER,
+	  .scope = OPTIONS_TABLE_SERVER,
+	  .minimum = INPUT_BUF_DEFAULT_SIZE,
+	  .maximum = UINT_MAX,
+	  .default_num = INPUT_BUF_DEFAULT_SIZE,
+	  .text = "Number of byte accpted in a single input before dropping."
+	},
+
 	{ .name = "menu-style",
 	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_WINDOW,

options.c

@@ -1177,6 +1177,8 @@ options_push_changes(const char *name)
 		RB_FOREACH(w, windows, &windows)
 			layout_fix_panes(w, NULL);
 	}
+	if (strcmp(name, "input-buffer-size") == 0)
+		input_set_buffer_size(options_get_number(global_options, name));
 	RB_FOREACH(s, sessions, &sessions)
 		status_update_cache(s);
 

tmux.1

@@ -4139,6 +4139,9 @@ option.
 If not empty, a file to which
 .Nm
 will write command prompt history on exit and load it from on start.
+.It Ic input-buffer-size Ar bytes
+Maximum of bytes allowed to read in escape and control sequences.
+Once reached, the sequence will be discarded.
 .It Ic message-limit Ar number
 Set the number of error or information messages to save in the message log for
 each client.

tmux.h

@@ -2840,6 +2840,7 @@ void	 recalculate_sizes(void);
 void	 recalculate_sizes_now(int);
 
 /* input.c */
+#define INPUT_BUF_DEFAULT_SIZE 1048576
 struct input_ctx *input_init(struct window_pane *, struct bufferevent *,
 	     struct colour_palette *);
 void	 input_free(struct input_ctx *);
@@ -2851,6 +2852,7 @@ void	 input_parse_screen(struct input_ctx *, struct screen *,
 	     screen_write_init_ctx_cb, void *, u_char *, size_t);
 void	 input_reply_clipboard(struct bufferevent *, const char *, size_t,
 	     const char *);
+void	 input_set_buffer_size(size_t);
 
 /* input-key.c */
 void	 input_key_build(void);