Support setting the xterm clipboard when copying from copy mode using

the xterm escape sequence for the purpose (if xterm is configured to
allow it).

Written by and much discussed Ailin Nemui, guidance on
xterm/termcap/terminfo from Thomas Dickey.

options-table.c

@@ -75,6 +75,11 @@ const struct options_table_entry server_options_table[] = {
 	  .default_num = 0 /* overridden in main() */
 	},
 
+	{ .name = "set-clipboard",
+	  .type = OPTIONS_TABLE_FLAG,
+	  .default_num = 1
+	},
+
 	{ .name = NULL }
 };
 
@@ -360,7 +365,8 @@ const struct options_table_entry session_options_table[] = {
 
 	{ .name = "terminal-overrides",
 	  .type = OPTIONS_TABLE_STRING,
-	  .default_str = "*88col*:colors=88,*256col*:colors=256,xterm*:XT"
+	  .default_str = "*88col*:colors=88,*256col*:colors=256"
+	  		 ",xterm*:XT:Ms=\\E]52;%p1%s;%p2%s\\007"
 	},
 
 	{ .name = "update-environment",

screen-write.c

@@ -1194,6 +1194,18 @@ screen_write_overwrite(struct screen_write_ctx *ctx, u_int width)
 	}
 }
 
+void
+screen_write_setselection(struct screen_write_ctx *ctx, u_char *str, u_int len)
+{
+	struct tty_ctx	ttyctx;
+
+	screen_write_initctx(ctx, &ttyctx, 0);
+	ttyctx.ptr = str;
+	ttyctx.num = len;
+
+	tty_write(tty_cmd_setselection, &ttyctx);
+}
+
 void
 screen_write_rawstring(struct screen_write_ctx *ctx, u_char *str, u_int len)
 {

tmux.1

@@ -1705,6 +1705,28 @@ Available server options are:
 Set the number of buffers; as new buffers are added to the top of the stack,
 old ones are removed from the bottom if necessary to maintain this maximum
 length.
+.It Xo Ic set-clipboard
+.Op Ic on | off
+.Xc
+Attempt to set the terminal clipboard content using the
+\ee]52;...\e007
+.Xr xterm 1
+escape sequences.
+This option is on by default if there is an
+.Em \&Ms
+entry in the
+.Xr terminfo 5
+description for the client terminal.
+Note that this feature needs to be enabled in
+.Xr xterm 1
+by setting the resource:
+.Bd -literal -offset indent
+disallowedWindowOps: 20,21,SetXprop
+.Ed
+.Pp
+Or changing this property from the
+.Xr xterm 1
+interactive menu when required.
 .It Ic escape-time Ar time
 Set the time in milliseconds for which
 .Nm
@@ -2796,6 +2818,21 @@ If the command doesn't return success, the exit status is also displayed.
 .D1 (alias: Ic info )
 Show server information and terminal details.
 .El
+.Sh TERMINFO EXTENSIONS
+.Nm
+understands some extensions to
+.Xr terminfo 5 :
+.Bl -tag -width Ds
+.It Em \&Ms
+This sequence can be used by
+.Nm
+to store the current buffer in the host terminal's selection (clipboard).
+See the
+.Em set-clipboard
+option above and the
+.Xr xterm 1
+man page.
+.El
 .Sh FILES
 .Bl -tag -width "/etc/tmux.confXXX" -compact
 .It Pa ~/.tmux.conf

tmux.h

@@ -308,6 +308,7 @@ enum tty_code_code {
 	TTYC_KUP5,
 	TTYC_KUP6,
 	TTYC_KUP7,
+	TTYC_MS,	/* modify xterm(1) selection */
 	TTYC_OP,	/* orig_pair, op */
 	TTYC_REV,	/* enter_reverse_mode, mr */
 	TTYC_RI,	/* scroll_reverse, sr */
@@ -1413,6 +1414,7 @@ void	tty_cursor(struct tty *, u_int, u_int);
 void	tty_putcode(struct tty *, enum tty_code_code);
 void	tty_putcode1(struct tty *, enum tty_code_code, int);
 void	tty_putcode2(struct tty *, enum tty_code_code, int, int);
+void	tty_putcode_ptr2(struct tty *, enum tty_code_code, const void *, const void *);
 void	tty_puts(struct tty *, const char *);
 void	tty_putc(struct tty *, u_char);
 void	tty_pututf8(struct tty *, const struct grid_utf8 *);
@@ -1444,6 +1446,7 @@ void	tty_cmd_insertline(struct tty *, const struct tty_ctx *);
 void	tty_cmd_linefeed(struct tty *, const struct tty_ctx *);
 void	tty_cmd_utf8character(struct tty *, const struct tty_ctx *);
 void	tty_cmd_reverseindex(struct tty *, const struct tty_ctx *);
+void	tty_cmd_setselection(struct tty *, const struct tty_ctx *);
 void	tty_cmd_rawstring(struct tty *, const struct tty_ctx *);
 
 /* tty-term.c */
@@ -1456,6 +1459,8 @@ const char	*tty_term_string(struct tty_term *, enum tty_code_code);
 const char	*tty_term_string1(struct tty_term *, enum tty_code_code, int);
 const char	*tty_term_string2(
 		     struct tty_term *, enum tty_code_code, int, int);
+const char	*tty_term_ptr2(
+		     struct tty_term *, enum tty_code_code, const void *, const void *);
 int		 tty_term_number(struct tty_term *, enum tty_code_code);
 int		 tty_term_flag(struct tty_term *, enum tty_code_code);
 
@@ -1824,6 +1829,7 @@ void	 screen_write_clearstartofscreen(struct screen_write_ctx *);
 void	 screen_write_clearscreen(struct screen_write_ctx *);
 void	 screen_write_cell(struct screen_write_ctx *,
 	     const struct grid_cell *, const struct utf8_data *);
+void	 screen_write_setselection(struct screen_write_ctx *, u_char *, u_int);
 void	 screen_write_rawstring(struct screen_write_ctx *, u_char *, u_int);
 
 /* screen-redraw.c */

tty-term.c

@@ -163,6 +163,7 @@ const struct tty_term_code_entry tty_term_codes[NTTYCODE] = {
 	{ TTYC_KUP5, TTYCODE_STRING, "kUP5" },
 	{ TTYC_KUP6, TTYCODE_STRING, "kUP6" },
 	{ TTYC_KUP7, TTYCODE_STRING, "kUP7" },
+	{ TTYC_MS, TTYCODE_STRING, "Ms" },
 	{ TTYC_OP, TTYCODE_STRING, "op" },
 	{ TTYC_REV, TTYCODE_STRING, "rev" },
 	{ TTYC_RI, TTYCODE_STRING, "ri" },
@@ -492,6 +493,12 @@ tty_term_string2(struct tty_term *term, enum tty_code_code code, int a, int b)
 	return (tparm((char *) tty_term_string(term, code), a, b));
 }
 
+const char *
+tty_term_ptr2(struct tty_term *term, enum tty_code_code code, const void *a, const void *b)
+{
+	return (tparm((char *) tty_term_string(term, code), a, b));
+}
+
 int
 tty_term_number(struct tty_term *term, enum tty_code_code code)
 {

tty.c

@@ -19,8 +19,11 @@
 #include <sys/types.h>
 #include <sys/ioctl.h>
 
+#include <netinet/in.h>
+
 #include <errno.h>
 #include <fcntl.h>
+#include <resolv.h>
 #include <stdlib.h>
 #include <string.h>
 #include <termios.h>
@@ -311,6 +314,13 @@ tty_putcode2(struct tty *tty, enum tty_code_code code, int a, int b)
 	tty_puts(tty, tty_term_string2(tty->term, code, a, b));
 }
 
+void
+tty_putcode_ptr2(struct tty *tty, enum tty_code_code code, const void *a, const void *b)
+{
+	if (a != NULL && b != NULL)
+		tty_puts(tty, tty_term_ptr2(tty->term, code, a, b));
+}
+
 void
 tty_puts(struct tty *tty, const char *s)
 {
@@ -938,6 +948,24 @@ tty_cmd_utf8character(struct tty *tty, const struct tty_ctx *ctx)
 	tty_draw_line(tty, wp->screen, ctx->ocy, wp->xoff, wp->yoff);
 }
 
+void
+tty_cmd_setselection(struct tty *tty, const struct tty_ctx *ctx)
+{
+	char	*buf;
+	size_t	 off;
+
+	if (!tty_term_has(tty->term, TTYC_MS))
+		return;
+
+	off = 4 * ((ctx->num + 2) / 3) + 1; /* storage for base64 */
+	buf = xmalloc(off);
+
+	b64_ntop(ctx->ptr, ctx->num, buf, off);
+	tty_putcode_ptr2(tty, TTYC_MS, "", buf);
+
+	xfree(buf);
+}
+
 void
 tty_cmd_rawstring(struct tty *tty, const struct tty_ctx *ctx)
 {

window-copy.c

@@ -1345,6 +1345,9 @@ window_copy_copy_selection(struct window_pane *wp)
 	}
 	off--;	/* remove final \n */
 
+	if (options_get_number(&global_options, "set-clipboard"))
+		screen_write_setselection(&wp->ictx.ctx, buf, off);
+
 	/* Add the buffer to the stack. */
 	limit = options_get_number(&global_options, "buffer-limit");
 	paste_add(&global_buffers, buf, off, limit);