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afb4ecad JD |
1 | /* Session management module for systems which understand the X Session |
2 | management protocol. | |
a0ecb2ac | 3 | Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. |
afb4ecad JD |
4 | |
5 | This file is part of GNU Emacs. | |
6 | ||
7 | GNU Emacs is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2, or (at your option) | |
10 | any later version. | |
11 | ||
12 | GNU Emacs is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GNU Emacs; see the file COPYING. If not, write to | |
19 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
20 | Boston, MA 02111-1307, USA. */ | |
21 | ||
22 | #include <config.h> | |
23 | ||
24 | #ifdef HAVE_X_SM | |
25 | ||
26 | #include <X11/SM/SMlib.h> | |
231d6cfb JD |
27 | #include <X11/Xlib.h> |
28 | #include <X11/Xutil.h> | |
29 | ||
afb4ecad JD |
30 | #ifdef HAVE_STRING_H |
31 | #include <string.h> | |
32 | #else | |
33 | #ifdef HAVE_STRINGS_H | |
34 | #include <strings.h> | |
35 | #endif | |
36 | #endif | |
37 | ||
38 | #ifdef HAVE_UNISTD_H | |
39 | #include <unistd.h> | |
40 | #endif | |
41 | #ifdef HAVE_STDLIB_H | |
42 | #include <stdlib.h> | |
43 | #endif | |
44 | ||
45 | #include <sys/param.h> | |
656132eb | 46 | #include <stdio.h> |
afb4ecad JD |
47 | |
48 | #include "systime.h" | |
49 | #include "sysselect.h" | |
50 | #include "lisp.h" | |
51 | #include "termhooks.h" | |
656132eb | 52 | #include "termopts.h" |
231d6cfb | 53 | #include "xterm.h" |
afb4ecad JD |
54 | |
55 | #ifndef MAXPATHLEN | |
56 | #define MAXPATHLEN 1024 | |
57 | #endif /* not MAXPATHLEN */ | |
58 | ||
59 | ||
60 | /* The user login name. */ | |
61 | ||
62 | extern Lisp_Object Vuser_login_name; | |
63 | ||
3b8f9651 | 64 | /* This is the event used when SAVE_SESSION_EVENT occurs. */ |
afb4ecad JD |
65 | |
66 | static struct input_event emacs_event; | |
67 | ||
3b8f9651 | 68 | /* The descriptor that we use to check for data from the session manager. */ |
afb4ecad JD |
69 | |
70 | static int ice_fd = -1; | |
71 | ||
3b8f9651 | 72 | /* A flag that says if we are in shutdown interactions or not. */ |
afb4ecad JD |
73 | |
74 | static int doing_interact = False; | |
75 | ||
76 | /* The session manager object for the session manager connection */ | |
77 | ||
78 | static SmcConn smc_conn; | |
79 | ||
80 | /* The client session id for this session */ | |
81 | static char *client_id; | |
82 | ||
83 | /* The full path name to the Emacs program */ | |
84 | static char *emacs_program; | |
85 | ||
86 | /* The client session id for this session as a lisp object. */ | |
87 | ||
88 | Lisp_Object Vx_session_id; | |
89 | ||
90 | /* The id we had the previous session. This is only available if we | |
91 | have been started by the session manager with SMID_OPT. */ | |
92 | ||
93 | Lisp_Object Vx_session_previous_id; | |
94 | ||
95 | /* The option we tell the session manager to start Emacs with when | |
96 | restarting Emacs. The client_id is appended. */ | |
97 | ||
98 | #define SMID_OPT "--smid=" | |
99 | ||
100 | ||
ca2417b9 JD |
101 | /* The option to start Emacs without the splash screen when |
102 | restarting Emacs. */ | |
103 | ||
104 | #define NOSPLASH_OPT "--no-splash" | |
105 | ||
106 | ||
afb4ecad JD |
107 | /* Handle any messages from the session manager. If no connection is |
108 | open to a session manager, just return 0. | |
a6950dfa | 109 | Otherwise returns 1 if SAVE_SESSION_EVENT is stored in buffer BUFP. */ |
afb4ecad | 110 | int |
a6950dfa | 111 | x_session_check_input (bufp) |
afb4ecad | 112 | struct input_event *bufp; |
afb4ecad JD |
113 | { |
114 | SELECT_TYPE read_fds; | |
115 | EMACS_TIME tmout; | |
7d0393cf | 116 | |
afb4ecad | 117 | if (ice_fd == -1) return 0; |
7d0393cf | 118 | |
afb4ecad JD |
119 | FD_ZERO (&read_fds); |
120 | FD_SET (ice_fd, &read_fds); | |
7d0393cf | 121 | |
afb4ecad JD |
122 | tmout.tv_sec = 0; |
123 | tmout.tv_usec = 0; | |
7d0393cf | 124 | |
afb4ecad JD |
125 | /* Reset this so wo can check kind after callbacks have been called by |
126 | IceProcessMessages. The smc_interact_CB sets the kind to | |
3b8f9651 | 127 | SAVE_SESSION_EVENT, but we don't know beforehand if that callback |
afb4ecad | 128 | will be called. */ |
3b8f9651 | 129 | emacs_event.kind = NO_EVENT; |
afb4ecad JD |
130 | |
131 | if (select (ice_fd+1, &read_fds, | |
132 | (SELECT_TYPE *)0, (SELECT_TYPE *)0, &tmout) < 0) | |
133 | { | |
134 | ice_fd = -1; | |
135 | return 0; | |
136 | } | |
7d0393cf | 137 | |
afb4ecad JD |
138 | |
139 | if (FD_ISSET (ice_fd, &read_fds)) | |
140 | IceProcessMessages (SmcGetIceConnection (smc_conn), | |
141 | (IceReplyWaitInfo *)0, (Bool *)0); | |
142 | ||
7d0393cf | 143 | |
afb4ecad | 144 | /* Check if smc_interact_CB was called and we shall generate a |
3b8f9651 | 145 | SAVE_SESSION_EVENT. */ |
a6950dfa KS |
146 | if (emacs_event.kind == NO_EVENT) |
147 | return 0; | |
afb4ecad | 148 | |
a6950dfa KS |
149 | bcopy (&emacs_event, bufp, sizeof (struct input_event)); |
150 | return 1; | |
afb4ecad JD |
151 | } |
152 | ||
153 | /* Return non-zero if we have a connection to a session manager.*/ | |
154 | int | |
155 | x_session_have_connection () | |
156 | { | |
157 | return ice_fd != -1; | |
158 | } | |
159 | ||
160 | /* This is called when the session manager says it is OK to interact with the | |
3b8f9651 | 161 | user. Here we set the kind to SAVE_SESSION_EVENT so an event is generated. |
afb4ecad JD |
162 | Then lisp code can interact with the user. */ |
163 | static void | |
164 | smc_interact_CB (smcConn, clientData) | |
165 | SmcConn smcConn; | |
166 | SmPointer clientData; | |
167 | { | |
168 | doing_interact = True; | |
3b8f9651 | 169 | emacs_event.kind = SAVE_SESSION_EVENT; |
afb4ecad JD |
170 | } |
171 | ||
f25dcaa0 | 172 | /* This is called when the session manager tells us to save ourselves. |
afb4ecad JD |
173 | We set the required properties so the session manager can restart us, |
174 | plus the current working directory property (not mandatory) so we | |
175 | are started in the correct directory. | |
176 | ||
177 | If this is a shutdown and we can request to interact with the user, | |
178 | we do so, because we don't know what the lisp code might do. */ | |
179 | static void | |
180 | smc_save_yourself_CB (smcConn, | |
181 | clientData, | |
182 | saveType, | |
183 | shutdown, | |
184 | interactStyle, | |
185 | fast) | |
186 | SmcConn smcConn; | |
187 | SmPointer clientData; | |
188 | int saveType; | |
189 | Bool shutdown; | |
190 | int interactStyle; | |
191 | Bool fast; | |
192 | { | |
193 | #define NR_PROPS 5 | |
7d0393cf | 194 | |
afb4ecad JD |
195 | SmProp *props[NR_PROPS]; |
196 | SmProp prop_ptr[NR_PROPS]; | |
7d0393cf | 197 | |
afb4ecad JD |
198 | SmPropValue values[20]; |
199 | int val_idx = 0; | |
200 | int props_idx = 0; | |
7d0393cf | 201 | |
afb4ecad JD |
202 | char cwd[MAXPATHLEN+1]; |
203 | char *smid_opt; | |
204 | ||
205 | /* How to start a new instance of Emacs */ | |
206 | props[props_idx] = &prop_ptr[props_idx]; | |
207 | props[props_idx]->name = SmCloneCommand; | |
208 | props[props_idx]->type = SmLISTofARRAY8; | |
209 | props[props_idx]->num_vals = 1; | |
210 | props[props_idx]->vals = &values[val_idx++]; | |
211 | props[props_idx]->vals[0].length = strlen (emacs_program); | |
212 | props[props_idx]->vals[0].value = emacs_program; | |
213 | ++props_idx; | |
214 | ||
215 | /* The name of the program */ | |
216 | props[props_idx] = &prop_ptr[props_idx]; | |
217 | props[props_idx]->name = SmProgram; | |
218 | props[props_idx]->type = SmARRAY8; | |
219 | props[props_idx]->num_vals = 1; | |
220 | props[props_idx]->vals = &values[val_idx++]; | |
d5db4077 KR |
221 | props[props_idx]->vals[0].length = strlen (SDATA (Vinvocation_name)); |
222 | props[props_idx]->vals[0].value = SDATA (Vinvocation_name); | |
afb4ecad | 223 | ++props_idx; |
7d0393cf | 224 | |
ca2417b9 | 225 | /* How to restart Emacs (i.e.: /path/to/emacs --smid=xxxx --no-splash). */ |
afb4ecad JD |
226 | props[props_idx] = &prop_ptr[props_idx]; |
227 | props[props_idx]->name = SmRestartCommand; | |
228 | props[props_idx]->type = SmLISTofARRAY8; | |
ca2417b9 | 229 | props[props_idx]->num_vals = 3; /* /path/to/emacs, --smid=xxx --no-splash */ |
afb4ecad JD |
230 | props[props_idx]->vals = &values[val_idx]; |
231 | props[props_idx]->vals[0].length = strlen (emacs_program); | |
232 | props[props_idx]->vals[0].value = emacs_program; | |
233 | ||
234 | smid_opt = xmalloc (strlen (SMID_OPT) + strlen (client_id) + 1); | |
235 | strcpy (smid_opt, SMID_OPT); | |
236 | strcat (smid_opt, client_id); | |
7d0393cf | 237 | |
afb4ecad JD |
238 | props[props_idx]->vals[1].length = strlen (smid_opt); |
239 | props[props_idx]->vals[1].value = smid_opt; | |
ca2417b9 JD |
240 | |
241 | props[props_idx]->vals[2].length = strlen (NOSPLASH_OPT); | |
242 | props[props_idx]->vals[2].value = NOSPLASH_OPT; | |
243 | val_idx += 3; | |
afb4ecad JD |
244 | ++props_idx; |
245 | ||
246 | /* User id */ | |
247 | props[props_idx] = &prop_ptr[props_idx]; | |
248 | props[props_idx]->name = SmUserID; | |
249 | props[props_idx]->type = SmARRAY8; | |
250 | props[props_idx]->num_vals = 1; | |
251 | props[props_idx]->vals = &values[val_idx++]; | |
d5db4077 KR |
252 | props[props_idx]->vals[0].length = strlen (SDATA (Vuser_login_name)); |
253 | props[props_idx]->vals[0].value = SDATA (Vuser_login_name); | |
afb4ecad JD |
254 | ++props_idx; |
255 | ||
256 | /* The current directory property, not mandatory */ | |
257 | #ifdef HAVE_GETCWD | |
258 | if (getcwd (cwd, MAXPATHLEN+1) != 0) | |
259 | #else | |
260 | if (getwd (cwd) != 0) | |
261 | #endif | |
262 | { | |
263 | props[props_idx] = &prop_ptr[props_idx]; | |
264 | props[props_idx]->name = SmCurrentDirectory; | |
265 | props[props_idx]->type = SmARRAY8; | |
266 | props[props_idx]->num_vals = 1; | |
267 | props[props_idx]->vals = &values[val_idx++]; | |
268 | props[props_idx]->vals[0].length = strlen (cwd); | |
269 | props[props_idx]->vals[0].value = cwd; | |
270 | ++props_idx; | |
271 | } | |
7d0393cf JB |
272 | |
273 | ||
afb4ecad JD |
274 | SmcSetProperties (smcConn, props_idx, props); |
275 | ||
276 | xfree (smid_opt); | |
277 | ||
278 | /* See if we maybe shall interact with the user. */ | |
279 | if (interactStyle != SmInteractStyleAny | |
280 | || ! shutdown | |
281 | || saveType == SmSaveLocal | |
282 | || ! SmcInteractRequest (smcConn, SmDialogNormal, smc_interact_CB, 0)) | |
283 | { | |
284 | /* No interaction, we are done saving ourself. */ | |
285 | SmcSaveYourselfDone (smcConn, True); | |
286 | } | |
287 | } | |
288 | ||
289 | /* According to the SM specification, this shall close the connection */ | |
290 | static void | |
291 | smc_die_CB (smcConn, clientData) | |
292 | SmcConn smcConn; | |
293 | SmPointer clientData; | |
294 | { | |
295 | SmcCloseConnection (smcConn, 0, 0); | |
296 | ice_fd = -1; | |
297 | } | |
298 | ||
299 | /* We don't use the next two but they are mandatory, leave them empty. | |
300 | According to the SM specification, we should not interact with the | |
301 | user between smc_save_yourself_CB is called and until smc_save_complete_CB | |
302 | is called. It seems like a lot of job to implement this and it doesn't | |
303 | even seem necessary. */ | |
304 | static void | |
305 | smc_save_complete_CB (smcConn, clientData) | |
306 | SmcConn smcConn; | |
307 | SmPointer clientData; | |
308 | { | |
309 | /* Empty */ | |
310 | } | |
311 | ||
312 | static void | |
313 | smc_shutdown_cancelled_CB (smcConn, clientData) | |
314 | SmcConn smcConn; | |
315 | SmPointer clientData; | |
316 | { | |
317 | /* Empty */ | |
318 | } | |
319 | ||
f25dcaa0 | 320 | /* Error handlers for SM and ICE. We don't want to exit Emacs just |
afb4ecad JD |
321 | because there is some error in the session management. */ |
322 | static void | |
323 | smc_error_handler (smcConn, | |
324 | swap, | |
325 | offendingMinorOpcode, | |
326 | offendingSequence, | |
327 | errorClass, | |
328 | severity, | |
329 | values) | |
330 | SmcConn smcConn; | |
331 | Bool swap; | |
332 | int offendingMinorOpcode; | |
333 | unsigned long offendingSequence; | |
334 | int errorClass; | |
335 | int severity; | |
336 | SmPointer values; | |
337 | { | |
338 | /* Empty */ | |
339 | } | |
340 | ||
341 | static void | |
342 | ice_error_handler (iceConn, | |
343 | swap, | |
344 | offendingMinorOpcode, | |
345 | offendingSequence, | |
346 | errorClass, | |
347 | severity, | |
348 | values) | |
349 | IceConn iceConn; | |
350 | Bool swap; | |
351 | int offendingMinorOpcode; | |
352 | unsigned long offendingSequence; | |
353 | int errorClass; | |
354 | int severity; | |
355 | IcePointer values; | |
356 | { | |
357 | /* Empty */ | |
358 | } | |
359 | ||
360 | ||
361 | static void | |
362 | ice_io_error_handler (iceConn) | |
363 | IceConn iceConn; | |
364 | { | |
365 | /* Connection probably gone. */ | |
366 | ice_fd = -1; | |
367 | } | |
368 | ||
369 | /* This is called when the ICE connection is created or closed. The SM library | |
370 | uses ICE as it transport protocol. */ | |
371 | static void | |
372 | ice_conn_watch_CB (iceConn, clientData, opening, watchData) | |
373 | IceConn iceConn; | |
374 | IcePointer clientData; | |
375 | Bool opening; | |
376 | IcePointer *watchData; | |
377 | { | |
378 | if (! opening) | |
379 | { | |
380 | ice_fd = -1; | |
381 | return; | |
382 | } | |
7d0393cf | 383 | |
afb4ecad JD |
384 | ice_fd = IceConnectionNumber (iceConn); |
385 | #ifndef F_SETOWN_BUG | |
386 | #ifdef F_SETOWN | |
387 | #ifdef F_SETOWN_SOCK_NEG | |
388 | /* stdin is a socket here */ | |
389 | fcntl (ice_fd, F_SETOWN, -getpid ()); | |
390 | #else /* ! defined (F_SETOWN_SOCK_NEG) */ | |
391 | fcntl (ice_fd, F_SETOWN, getpid ()); | |
392 | #endif /* ! defined (F_SETOWN_SOCK_NEG) */ | |
393 | #endif /* ! defined (F_SETOWN) */ | |
394 | #endif /* F_SETOWN_BUG */ | |
395 | ||
396 | #ifdef SIGIO | |
397 | if (interrupt_input) | |
398 | init_sigio (ice_fd); | |
399 | #endif /* ! defined (SIGIO) */ | |
400 | } | |
401 | ||
231d6cfb JD |
402 | /* Create the client leader window. */ |
403 | static void | |
404 | create_client_leader_window (dpyinfo, client_id) | |
405 | struct x_display_info *dpyinfo; | |
406 | char *client_id; | |
407 | { | |
408 | Window w; | |
409 | XClassHint class_hints; | |
410 | Atom sm_id; | |
411 | ||
412 | w = XCreateSimpleWindow (dpyinfo->display, | |
413 | dpyinfo->root_window, | |
414 | -1, -1, 1, 1, | |
415 | CopyFromParent, CopyFromParent, CopyFromParent); | |
416 | ||
417 | class_hints.res_name = (char *) SDATA (Vx_resource_name); | |
418 | class_hints.res_class = (char *) SDATA (Vx_resource_class); | |
419 | XSetClassHint (dpyinfo->display, w, &class_hints); | |
420 | XStoreName (dpyinfo->display, w, class_hints.res_name); | |
421 | ||
422 | sm_id = XInternAtom (dpyinfo->display, "SM_CLIENT_ID", False); | |
423 | XChangeProperty (dpyinfo->display, w, sm_id, XA_STRING, 8, PropModeReplace, | |
424 | client_id, strlen (client_id)); | |
425 | ||
426 | dpyinfo->client_leader_window = w; | |
427 | } | |
428 | ||
afb4ecad JD |
429 | /* Try to open a connection to the session manager. */ |
430 | void | |
231d6cfb JD |
431 | x_session_initialize (dpyinfo) |
432 | struct x_display_info *dpyinfo; | |
afb4ecad JD |
433 | { |
434 | #define SM_ERRORSTRING_LEN 512 | |
435 | char errorstring[SM_ERRORSTRING_LEN]; | |
436 | char* previous_id = NULL; | |
437 | SmcCallbacks callbacks; | |
438 | int name_len = 0; | |
7d0393cf | 439 | |
afb4ecad JD |
440 | /* Check if we where started by the session manager. If so, we will |
441 | have a previous id. */ | |
442 | if (! EQ (Vx_session_previous_id, Qnil) && STRINGP (Vx_session_previous_id)) | |
d5db4077 | 443 | previous_id = SDATA (Vx_session_previous_id); |
afb4ecad JD |
444 | |
445 | /* Construct the path to the Emacs program. */ | |
446 | if (! EQ (Vinvocation_directory, Qnil)) | |
d5db4077 KR |
447 | name_len += strlen (SDATA (Vinvocation_directory)); |
448 | name_len += strlen (SDATA (Vinvocation_name)); | |
afb4ecad JD |
449 | |
450 | /* This malloc will not be freed, but it is only done once, and hopefully | |
451 | not very large */ | |
452 | emacs_program = xmalloc (name_len + 1); | |
453 | emacs_program[0] = '\0'; | |
454 | ||
455 | if (! EQ (Vinvocation_directory, Qnil)) | |
d5db4077 KR |
456 | strcpy (emacs_program, SDATA (Vinvocation_directory)); |
457 | strcat (emacs_program, SDATA (Vinvocation_name)); | |
7d0393cf | 458 | |
afb4ecad JD |
459 | /* The SM protocol says all callbacks are mandatory, so set up all |
460 | here and in the mask passed to SmcOpenConnection */ | |
461 | callbacks.save_yourself.callback = smc_save_yourself_CB; | |
462 | callbacks.save_yourself.client_data = 0; | |
463 | callbacks.die.callback = smc_die_CB; | |
464 | callbacks.die.client_data = 0; | |
465 | callbacks.save_complete.callback = smc_save_complete_CB; | |
466 | callbacks.save_complete.client_data = 0; | |
467 | callbacks.shutdown_cancelled.callback = smc_shutdown_cancelled_CB; | |
468 | callbacks.shutdown_cancelled.client_data = 0; | |
469 | ||
470 | /* Set error handlers. */ | |
471 | SmcSetErrorHandler (smc_error_handler); | |
472 | IceSetErrorHandler (ice_error_handler); | |
473 | IceSetIOErrorHandler (ice_io_error_handler); | |
474 | ||
475 | /* Install callback for when connection status changes. */ | |
476 | IceAddConnectionWatch (ice_conn_watch_CB, 0); | |
477 | ||
478 | /* Open the connection to the session manager. A failure is not | |
f25dcaa0 | 479 | critical, it usually means that no session manager is running. |
afb4ecad JD |
480 | The errorstring is here for debugging. */ |
481 | smc_conn = SmcOpenConnection (NULL, NULL, 1, 0, | |
482 | (SmcSaveYourselfProcMask| | |
483 | SmcDieProcMask| | |
484 | SmcSaveCompleteProcMask| | |
485 | SmcShutdownCancelledProcMask), | |
486 | &callbacks, | |
487 | previous_id, | |
488 | &client_id, | |
489 | SM_ERRORSTRING_LEN, | |
490 | errorstring); | |
491 | ||
492 | if (smc_conn != 0) | |
231d6cfb JD |
493 | { |
494 | Vx_session_id = make_string (client_id, strlen (client_id)); | |
495 | ||
496 | #ifdef USE_GTK | |
497 | /* GTK creats a leader window by itself, but we need to tell | |
498 | it about our client_id. */ | |
499 | gdk_set_sm_client_id (client_id); | |
500 | #else | |
501 | create_client_leader_window (dpyinfo, client_id); | |
502 | #endif | |
503 | } | |
afb4ecad JD |
504 | } |
505 | ||
506 | ||
507 | DEFUN ("handle-save-session", Fhandle_save_session, | |
508 | Shandle_save_session, 1, 1, "e", | |
509 | doc: /* Handle the save_yourself event from a session manager. | |
7d0393cf | 510 | A session manager can tell Emacs that the window system is shutting down |
afb4ecad JD |
511 | by sending Emacs a save_yourself message. Emacs executes this function when |
512 | such an event occurs. This function then executes `emacs-session-save'. | |
513 | After that, this function informs the session manager that it can continue | |
514 | or abort shutting down the window system depending on the return value | |
515 | from `emacs-session-save' If the return value is non-nil the session manager | |
516 | is told to abort the window system shutdown. | |
517 | ||
518 | Do not call this function yourself. */) | |
519 | (event) | |
520 | Lisp_Object event; | |
521 | { | |
522 | /* Check doing_interact so that we don't do anything if someone called | |
523 | this at the wrong time. */ | |
524 | if (doing_interact) | |
525 | { | |
526 | Bool cancel_shutdown = False; | |
527 | ||
528 | cancel_shutdown = ! EQ (call0 (intern ("emacs-session-save")), Qnil); | |
529 | ||
530 | SmcInteractDone (smc_conn, cancel_shutdown); | |
531 | SmcSaveYourselfDone (smc_conn, True); | |
532 | ||
533 | doing_interact = False; | |
534 | } | |
ad4ace7a JD |
535 | |
536 | return Qnil; | |
afb4ecad JD |
537 | } |
538 | ||
539 | \f | |
540 | /*********************************************************************** | |
541 | Initialization | |
542 | ***********************************************************************/ | |
543 | void | |
544 | syms_of_xsmfns () | |
545 | { | |
546 | DEFVAR_LISP ("x-session-id", &Vx_session_id, | |
547 | doc: /* The session id Emacs got from the session manager for this session. | |
548 | Changing the value does not change the session id used by Emacs. | |
549 | The value is nil if no session manager is running. | |
550 | See also `x-session-previous-id', `emacs-save-session-functions', | |
551 | `emacs-session-save' and `emacs-session-restore'." */); | |
552 | Vx_session_id = Qnil; | |
553 | ||
554 | DEFVAR_LISP ("x-session-previous-id", &Vx_session_previous_id, | |
555 | doc: /* The previous session id Emacs got from session manager. | |
7d0393cf JB |
556 | If Emacs is running on a window system that has a session manager, the |
557 | session manager gives Emacs a session id. It is feasible for Emacs lisp | |
558 | code to use the session id to save configuration in, for example, a file | |
559 | with a file name based on the session id. If Emacs is running when the | |
560 | window system is shut down, the session manager remembers that Emacs was | |
afb4ecad JD |
561 | running and saves the session id Emacs had. |
562 | ||
7d0393cf JB |
563 | When the window system is started again, the session manager restarts |
564 | Emacs and hands Emacs the session id it had the last time it was | |
565 | running. This is now the previous session id and the value of this | |
566 | variable. If configuration was saved in a file as stated above, the | |
afb4ecad JD |
567 | previous session id shall be used to reconstruct the file name. |
568 | ||
7d0393cf | 569 | The session id Emacs has while it is running is in the variable |
afb4ecad JD |
570 | `x-session-id'. The value of this variable and `x-session-id' may be the |
571 | same, depending on how the session manager works. | |
572 | ||
573 | See also `emacs-save-session-functions', `emacs-session-save' and | |
574 | `emacs-session-restore'." */); | |
575 | Vx_session_previous_id = Qnil; | |
7d0393cf | 576 | |
afb4ecad JD |
577 | defsubr (&Shandle_save_session); |
578 | } | |
579 | ||
580 | #endif /* HAVE_X_SM */ | |
ab5796a9 MB |
581 | |
582 | /* arch-tag: 56a2c58c-adfa-430a-b772-130abd29fd2e | |
583 | (do not change this comment) */ |