Allow programs running in kitty to read/write from the clipboard

By default only writing is allowed. There is a config option to enable
reading, if needed.

kitty/config.py

@@ -355,6 +355,7 @@ type_map = {
     'bell_on_tab': to_bool,
     'kitty_mod': to_modifiers,
     'clear_all_shortcuts': to_bool,
+    'clipboard_control': lambda x: frozenset(x.lower().split()),
 }
 
 for name in (

kitty/kitty.conf

@@ -318,6 +318,14 @@ close_on_child_death no
 # Note that this even works over ssh connections.
 allow_remote_control no
 
+# Allow programs running in kitty to read and write from the clipboard. You can
+# control exactly which actions are allowed. The set of possible actions is:
+# write-clipboard read-clipboard write-primary read-primary
+# The default is to allow writing to the clipboard and primary selection. Note
+# that enabling the read functionality is a security risk as it means that any
+# program, even one running on a remote server via SSH can read your clipboard.
+clipboard_control write-clipboard write-primary
+
 # The value of the TERM environment variable to set. Changing this can break
 # many terminal programs, only change it if you know what you are doing, not
 # because you read some advice on Stack Overflow to change it.

kitty/parser.c

@@ -341,6 +341,9 @@ dispatch_osc(Screen *screen, PyObject DUMP_UNUSED *dump_callback) {
             case 119:
                 SET_COLOR(set_dynamic_color);
                 break;
+            case 52:
+                DISPATCH_OSC(clipboard_control);
+                break;
             default:
                 REPORT_ERROR("Unknown OSC code: %u", code);
                 break;

kitty/screen.c

@@ -1194,6 +1194,11 @@ set_dynamic_color(Screen *self, unsigned int code, PyObject *color) {
     else { CALLBACK("set_dynamic_color", "IO", code, color); }
 }
 
+void
+clipboard_control(Screen *self, PyObject *data) {
+    CALLBACK("clipboard_control", "O", data);
+}
+
 void
 set_color_table_color(Screen *self, unsigned int code, PyObject *color) {
     if (color == NULL) { CALLBACK("set_color_table_color", "Is", code, ""); }

kitty/screen.h

@@ -143,6 +143,7 @@ void screen_use_latin1(Screen *, bool);
 void set_title(Screen *self, PyObject*);
 void set_icon(Screen *self, PyObject*);
 void set_dynamic_color(Screen *self, unsigned int code, PyObject*);
+void clipboard_control(Screen *self, PyObject*);
 void set_color_table_color(Screen *self, unsigned int code, PyObject*);
 uint32_t* translation_table(uint32_t which);
 void screen_request_capabilities(Screen *, char, PyObject *);

kitty/window.py

@@ -17,17 +17,17 @@ from .fast_data_types import (
     BLIT_PROGRAM, CELL_BG_PROGRAM, CELL_FG_PROGRAM, CELL_PROGRAM,
     CELL_SPECIAL_PROGRAM, CSI, CURSOR_PROGRAM, DCS, GRAPHICS_PREMULT_PROGRAM,
     GRAPHICS_PROGRAM, OSC, SCROLL_FULL, SCROLL_LINE, SCROLL_PAGE, Screen,
-    add_window, compile_program, glfw_post_empty_event, init_cell_program,
-    init_cursor_program, set_clipboard_string, set_titlebar_color,
-    set_window_render_data, update_window_title, update_window_visibility,
-    viewport_for_window
+    add_window, compile_program, get_clipboard_string, glfw_post_empty_event,
+    init_cell_program, init_cursor_program, set_clipboard_string,
+    set_titlebar_color, set_window_render_data, update_window_title,
+    update_window_visibility, viewport_for_window
 )
 from .keys import keyboard_mode_name
 from .rgb import to_color
 from .terminfo import get_capabilities
 from .utils import (
-    color_as_int, load_shaders, open_cmd, open_url, parse_color_set,
-    sanitize_title
+    color_as_int, get_primary_selection, load_shaders, log_error, open_cmd,
+    open_url, parse_color_set, sanitize_title, set_primary_selection
 )
 
 
@@ -331,6 +331,37 @@ class Window:
     def send_cmd_response(self, response):
         self.screen.send_escape_code_to_child(DCS, '@kitty-cmd' + json.dumps(response))
 
+    def clipboard_control(self, data):
+        where, text = data.partition(';')[::2]
+        if text == '?':
+            response = None
+            if 'read-clipboard' in self.opts.clipboard_control and ('s' in where or 'c' in where):
+                response = get_clipboard_string()
+                loc = 'c'
+            elif 'p' in where and 'read-primary' in self.opts.clipboard_control:
+                response = get_primary_selection()
+                loc = 'p'
+            if response is not None:
+                from base64 import standard_b64encode
+                self.screen.send_escape_code_to_child(OSC, '{};{}'.format(
+                    loc, standard_b64encode(response.encode('utf-8')).decode('ascii')))
+
+        else:
+            from base64 import standard_b64decode
+            try:
+                text = standard_b64decode(text).decode('utf-8')
+            except Exception:
+                log_error('Invalid data to write to clipboard received, ignoring')
+                return
+            if 's' in where or 'c' in where:
+                if 'write-clipboard' in self.opts.clipboard_control:
+                    set_clipboard_string(text)
+            if 'p' in where:
+                if self.opts.copy_on_select:
+                    if 'write-clipboard' in self.opts.clipboard_control:
+                        set_clipboard_string(text)
+                if 'write-primary' in self.opts.clipboard_control:
+                    set_primary_selection(text)
     # }}}
 
     def text_for_selection(self):