src/xsmfns.c

   1 /* Session management module for systems which understand the X Session
   2    management protocol.
   3
   4 Copyright (C) 2002-2015 Free Software Foundation, Inc.
   5
   6 This file is part of GNU Emacs.
   7
   8 GNU Emacs is free software: you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation, either version 3 of the License, or
  11 (at your option) any later version.
  12
  13 GNU Emacs is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include <config.h>
  22
  23 #ifdef HAVE_X_SM
  24
  25 #include <X11/SM/SMlib.h>
  26 #include <X11/Xlib.h>
  27 #include <X11/Xutil.h>
  28
  29 #include <unistd.h>
  30 #include <sys/param.h>
  31 #include <stdio.h>
  32
  33 #include "lisp.h"
  34 #include "systime.h"
  35 #include "sysselect.h"
  36 #include "frame.h"
  37 #include "termhooks.h"
  38 #include "xterm.h"
  39 #include "process.h"
  40 #include "keyboard.h"
  41
  42 #if defined USE_GTK && !defined HAVE_GTK3
  43 #define gdk_x11_set_sm_client_id(w) gdk_set_sm_client_id (w)
  44 #endif
  45
  46 /* This is the event used when SAVE_SESSION_EVENT occurs.  */
  47
  48 static struct input_event emacs_event;
  49
  50 /* The descriptor that we use to check for data from the session manager.  */
  51
  52 static int ice_fd = -1;
  53
  54 /* A flag that says if we are in shutdown interactions or not.  */
  55
  56 static bool doing_interact;
  57
  58 /* The session manager object for the session manager connection.  */
  59
  60 static SmcConn smc_conn;
  61
  62 /* The client session id for this session.  */
  63
  64 static char *client_id;
  65
  66 /* The full path name to the Emacs program.  */
  67
  68 static char *emacs_program;
  69
  70 /* The option we tell the session manager to start Emacs with when
  71    restarting Emacs.  The client_id is appended.  */
  72
  73 #define SMID_OPT "--smid="
  74
  75
  76 /* The option to start Emacs without the splash screen when
  77    restarting Emacs.  */
  78
  79 static char NOSPLASH_OPT[] = "--no-splash";
  80
  81 /* The option to make Emacs start in the given directory.  */
  82
  83 #define CHDIR_OPT "--chdir="
  84
  85 static void
  86 ice_connection_closed (void)
  87 {
  88   if (ice_fd >= 0)
  89     delete_read_fd (ice_fd);
  90   ice_fd = -1;
  91 }
  92
  93
  94 /* Handle any messages from the session manager.  If no connection is
  95    open to a session manager, just return.  */
  96
  97 static void
  98 x_session_check_input (int fd, void *data)
  99 {
 100   int ret;
 101
 102   if (ice_fd == -1) return;
 103
 104   /* Reset this so wo can check kind after callbacks have been called by
 105      IceProcessMessages.  The smc_interact_CB sets the kind to
 106      SAVE_SESSION_EVENT, but we don't know beforehand if that callback
 107      will be called.  */
 108   emacs_event.kind = NO_EVENT;
 109
 110   ret = IceProcessMessages (SmcGetIceConnection (smc_conn), 0, 0);
 111   if (ret != IceProcessMessagesSuccess)
 112     {
 113       /* Either IO error or Connection closed.  */
 114       if (ret == IceProcessMessagesIOError)
 115         IceCloseConnection (SmcGetIceConnection (smc_conn));
 116
 117       ice_connection_closed ();
 118     }
 119
 120   /* Check if smc_interact_CB was called and we shall generate a
 121      SAVE_SESSION_EVENT.  */
 122   if (emacs_event.kind != NO_EVENT)
 123     kbd_buffer_store_event (&emacs_event);
 124 }
 125
 126 /* Return true if we have a connection to a session manager.  */
 127
 128 bool
 129 x_session_have_connection (void)
 130 {
 131   return ice_fd != -1;
 132 }
 133
 134 /* This is called when the session manager says it is OK to interact with the
 135    user.  Here we set the kind to SAVE_SESSION_EVENT so an event is generated.
 136    Then lisp code can interact with the user.  */
 137
 138 static void
 139 smc_interact_CB (SmcConn smcConn, SmPointer clientData)
 140 {
 141   doing_interact = true;
 142   emacs_event.kind = SAVE_SESSION_EVENT;
 143   emacs_event.arg = Qnil;
 144 }
 145
 146 /* This is called when the session manager tells us to save ourselves.
 147    We set the required properties so the session manager can restart us,
 148    plus the current working directory property (not mandatory) so we
 149    are started in the correct directory.
 150
 151    If this is a shutdown and we can request to interact with the user,
 152    we do so, because we don't know what the lisp code might do.  */
 153
 154 static void
 155 smc_save_yourself_CB (SmcConn smcConn,
 156                       SmPointer clientData,
 157                       int saveType,
 158                       Bool shutdown,
 159                       int interactStyle,
 160                       Bool fast)
 161 {
 162 #define NR_PROPS 5
 163
 164   SmProp *props[NR_PROPS];
 165   SmProp prop_ptr[NR_PROPS];
 166
 167   SmPropValue values[20], *vp;
 168   int val_idx = 0, vp_idx = 0;
 169   int props_idx = 0;
 170   int i;
 171   char *cwd = get_current_dir_name ();
 172   char *smid_opt, *chdir_opt = NULL;
 173
 174   /* How to start a new instance of Emacs.  */
 175   props[props_idx] = &prop_ptr[props_idx];
 176   props[props_idx]->name = xstrdup (SmCloneCommand);
 177   props[props_idx]->type = xstrdup (SmLISTofARRAY8);
 178   props[props_idx]->num_vals = 1;
 179   props[props_idx]->vals = &values[val_idx++];
 180   props[props_idx]->vals[0].length = strlen (emacs_program);
 181   props[props_idx]->vals[0].value = emacs_program;
 182   ++props_idx;
 183
 184   /* The name of the program.  */
 185   props[props_idx] = &prop_ptr[props_idx];
 186   props[props_idx]->name = xstrdup (SmProgram);
 187   props[props_idx]->type = xstrdup (SmARRAY8);
 188   props[props_idx]->num_vals = 1;
 189   props[props_idx]->vals = &values[val_idx++];
 190   props[props_idx]->vals[0].length = SBYTES (Vinvocation_name);
 191   props[props_idx]->vals[0].value = SDATA (Vinvocation_name);
 192   ++props_idx;
 193
 194   /* User id.  */
 195   props[props_idx] = &prop_ptr[props_idx];
 196   props[props_idx]->name = xstrdup (SmUserID);
 197   props[props_idx]->type = xstrdup (SmARRAY8);
 198   props[props_idx]->num_vals = 1;
 199   props[props_idx]->vals = &values[val_idx++];
 200   props[props_idx]->vals[0].length = SBYTES (Vuser_login_name);
 201   props[props_idx]->vals[0].value = SDATA (Vuser_login_name);
 202   ++props_idx;
 203
 204
 205   if (cwd)
 206     {
 207       props[props_idx] = &prop_ptr[props_idx];
 208       props[props_idx]->name = xstrdup (SmCurrentDirectory);
 209       props[props_idx]->type = xstrdup (SmARRAY8);
 210       props[props_idx]->num_vals = 1;
 211       props[props_idx]->vals = &values[val_idx++];
 212       props[props_idx]->vals[0].length = strlen (cwd);
 213       props[props_idx]->vals[0].value = cwd;
 214       ++props_idx;
 215     }
 216
 217
 218   /* How to restart Emacs.  */
 219   props[props_idx] = &prop_ptr[props_idx];
 220   props[props_idx]->name = xstrdup (SmRestartCommand);
 221   props[props_idx]->type = xstrdup (SmLISTofARRAY8);
 222   /* /path/to/emacs, --smid=xxx --no-splash --chdir=dir ... */
 223   if (INT_MAX - 3 < initial_argc)
 224     memory_full (SIZE_MAX);
 225   i = 3 + initial_argc;
 226   props[props_idx]->num_vals = i;
 227   vp = xnmalloc (i, sizeof *vp);
 228   props[props_idx]->vals = vp;
 229   props[props_idx]->vals[vp_idx].length = strlen (emacs_program);
 230   props[props_idx]->vals[vp_idx++].value = emacs_program;
 231
 232   smid_opt = xmalloc (strlen (SMID_OPT) + strlen (client_id) + 1);
 233   strcpy (stpcpy (smid_opt, SMID_OPT), client_id);
 234
 235   props[props_idx]->vals[vp_idx].length = strlen (smid_opt);
 236   props[props_idx]->vals[vp_idx++].value = smid_opt;
 237
 238   props[props_idx]->vals[vp_idx].length = strlen (NOSPLASH_OPT);
 239   props[props_idx]->vals[vp_idx++].value = NOSPLASH_OPT;
 240
 241   if (cwd)
 242     {
 243       chdir_opt = xmalloc (strlen (CHDIR_OPT) + strlen (cwd) + 1);
 244       strcpy (stpcpy (chdir_opt, CHDIR_OPT), cwd);
 245
 246       props[props_idx]->vals[vp_idx].length = strlen (chdir_opt);
 247       props[props_idx]->vals[vp_idx++].value = chdir_opt;
 248     }
 249
 250   for (i = 1; i < initial_argc; ++i)
 251     {
 252       props[props_idx]->vals[vp_idx].length = strlen (initial_argv[i]);
 253       props[props_idx]->vals[vp_idx++].value = initial_argv[i];
 254     }
 255
 256   ++props_idx;
 257
 258   SmcSetProperties (smcConn, props_idx, props);
 259
 260   xfree (smid_opt);
 261   xfree (chdir_opt);
 262   xfree (cwd);
 263   xfree (vp);
 264
 265   for (i = 0; i < props_idx; ++i)
 266     {
 267       xfree (props[i]->type);
 268       xfree (props[i]->name);
 269     }
 270
 271   /* See if we maybe shall interact with the user.  */
 272   if (interactStyle != SmInteractStyleAny
 273       || ! shutdown
 274       || saveType == SmSaveLocal
 275       || ! SmcInteractRequest (smcConn, SmDialogNormal, smc_interact_CB, 0))
 276     {
 277       /* No interaction, we are done saving ourself.  */
 278       SmcSaveYourselfDone (smcConn, True);
 279     }
 280 }
 281
 282 /* According to the SM specification, this shall close the connection.  */
 283
 284 static void
 285 smc_die_CB (SmcConn smcConn, SmPointer clientData)
 286 {
 287   emacs_event.kind = SAVE_SESSION_EVENT;
 288   emacs_event.arg = Qt;
 289 }
 290
 291 /* We don't use the next two but they are mandatory, leave them empty.
 292    According to the SM specification, we should not interact with the
 293    user between smc_save_yourself_CB is called and until smc_save_complete_CB
 294    is called.  It seems like a lot of job to implement this and it doesn't
 295    even seem necessary.  */
 296
 297 static void
 298 smc_save_complete_CB (SmcConn smcConn, SmPointer clientData)
 299 {
 300   /* Empty */
 301 }
 302
 303 static void
 304 smc_shutdown_cancelled_CB (SmcConn smcConn, SmPointer clientData)
 305 {
 306   /* Empty */
 307 }
 308
 309 /* Error handlers for SM and ICE.  We don't want to exit Emacs just
 310    because there is some error in the session management.  */
 311
 312 static void
 313 smc_error_handler (SmcConn smcConn,
 314                    Bool swap,
 315                    int offendingMinorOpcode,
 316                    unsigned long offendingSequence,
 317                    int errorClass,
 318                    int severity,
 319                    SmPointer values)
 320 {
 321   /* Empty  */
 322 }
 323
 324 static void
 325 ice_error_handler (IceConn iceConn,
 326                    Bool swap,
 327                    int offendingMinorOpcode,
 328                    unsigned long offendingSequence,
 329                    int errorClass,
 330                    int severity,
 331                    IcePointer values)
 332 {
 333   /* Empty  */
 334 }
 335
 336
 337 static void
 338 ice_io_error_handler (IceConn iceConn)
 339 {
 340   /* Connection probably gone.  */
 341   ice_connection_closed ();
 342 }
 343
 344 /* This is called when the ICE connection is created or closed.  The SM library
 345    uses ICE as it transport protocol.  */
 346
 347 static void
 348 ice_conn_watch_CB (IceConn iceConn, IcePointer clientData,
 349                    int opening, IcePointer *watchData)
 350 {
 351   if (! opening)
 352     {
 353       ice_connection_closed ();
 354       return;
 355     }
 356
 357   ice_fd = IceConnectionNumber (iceConn);
 358   add_read_fd (ice_fd, x_session_check_input, NULL);
 359 }
 360
 361 /* Create the client leader window.  */
 362
 363 #ifndef USE_GTK
 364 static void
 365 create_client_leader_window (struct x_display_info *dpyinfo, char *client_ID)
 366 {
 367   Window w;
 368   XClassHint class_hints;
 369
 370   w = XCreateSimpleWindow (dpyinfo->display,
 371                            dpyinfo->root_window,
 372                            -1, -1, 1, 1,
 373                            CopyFromParent, CopyFromParent, CopyFromParent);
 374
 375   class_hints.res_name = SSDATA (Vx_resource_name);
 376   class_hints.res_class = SSDATA (Vx_resource_class);
 377   XSetClassHint (dpyinfo->display, w, &class_hints);
 378   XStoreName (dpyinfo->display, w, class_hints.res_name);
 379
 380   XChangeProperty (dpyinfo->display, w, dpyinfo->Xatom_SM_CLIENT_ID,
 381                    XA_STRING, 8, PropModeReplace,
 382                    (unsigned char *) client_ID, strlen (client_ID));
 383
 384   dpyinfo->client_leader_window = w;
 385 }
 386 #endif /* ! USE_GTK */
 387
 388
 389 /* Try to open a connection to the session manager.  */
 390
 391 void
 392 x_session_initialize (struct x_display_info *dpyinfo)
 393 {
 394 #define SM_ERRORSTRING_LEN 512
 395   char errorstring[SM_ERRORSTRING_LEN];
 396   char *previous_id = NULL;
 397   SmcCallbacks callbacks;
 398   ptrdiff_t name_len = 0;
 399
 400   ice_fd = -1;
 401   doing_interact = false;
 402
 403   /* Check if we where started by the session manager.  If so, we will
 404      have a previous id.  */
 405   if (! NILP (Vx_session_previous_id) && STRINGP (Vx_session_previous_id))
 406     previous_id = SSDATA (Vx_session_previous_id);
 407
 408   /* Construct the path to the Emacs program.  */
 409   if (! NILP (Vinvocation_directory))
 410     name_len += SBYTES (Vinvocation_directory);
 411   name_len += SBYTES (Vinvocation_name);
 412
 413   /* This malloc will not be freed, but it is only done once, and hopefully
 414      not very large   */
 415   emacs_program = xmalloc (name_len + 1);
 416   char *z = emacs_program;
 417
 418   if (! NILP (Vinvocation_directory))
 419     z = lispstpcpy (z, Vinvocation_directory);
 420   lispstpcpy (z, Vinvocation_name);
 421
 422   /* The SM protocol says all callbacks are mandatory, so set up all
 423      here and in the mask passed to SmcOpenConnection.  */
 424   callbacks.save_yourself.callback = smc_save_yourself_CB;
 425   callbacks.save_yourself.client_data = 0;
 426   callbacks.die.callback = smc_die_CB;
 427   callbacks.die.client_data = 0;
 428   callbacks.save_complete.callback = smc_save_complete_CB;
 429   callbacks.save_complete.client_data = 0;
 430   callbacks.shutdown_cancelled.callback = smc_shutdown_cancelled_CB;
 431   callbacks.shutdown_cancelled.client_data = 0;
 432
 433   /* Set error handlers.  */
 434   SmcSetErrorHandler (smc_error_handler);
 435   IceSetErrorHandler (ice_error_handler);
 436   IceSetIOErrorHandler (ice_io_error_handler);
 437
 438   /* Install callback for when connection status changes.  */
 439   IceAddConnectionWatch (ice_conn_watch_CB, 0);
 440
 441   /* Open the connection to the session manager.  A failure is not
 442      critical, it usually means that no session manager is running.
 443      The errorstring is here for debugging.  */
 444   smc_conn = SmcOpenConnection (NULL, NULL, 1, 0,
 445                                 (SmcSaveYourselfProcMask|
 446                                  SmcDieProcMask|
 447                                  SmcSaveCompleteProcMask|
 448                                  SmcShutdownCancelledProcMask),
 449                                 &callbacks,
 450                                 previous_id,
 451                                 &client_id,
 452                                 SM_ERRORSTRING_LEN,
 453                                 errorstring);
 454
 455   if (smc_conn != 0)
 456     {
 457       Vx_session_id = build_string (client_id);
 458
 459 #ifdef USE_GTK
 460       /* GTK creates a leader window by itself, but we need to tell
 461          it about our client_id.  */
 462       gdk_x11_set_sm_client_id (client_id);
 463 #else
 464       create_client_leader_window (dpyinfo, client_id);
 465 #endif
 466     }
 467 }
 468
 469 /* Ensure that the session manager is not contacted again. */
 470
 471 void
 472 x_session_close (void)
 473 {
 474   ice_connection_closed ();
 475 }
 476
 477
 478 DEFUN ("handle-save-session", Fhandle_save_session,
 479        Shandle_save_session, 1, 1, "e",
 480        doc: /* Handle the save_yourself event from a session manager.
 481 A session manager can tell Emacs that the window system is shutting down
 482 by sending Emacs a save_yourself message.  Emacs executes this function when
 483 such an event occurs.  This function then executes `emacs-session-save'.
 484 After that, this function informs the session manager that it can continue
 485 or abort shutting down the window system depending on the return value
 486 from `emacs-session-save'  If the return value is non-nil the session manager
 487 is told to abort the window system shutdown.
 488
 489 Do not call this function yourself. */)
 490   (Lisp_Object event)
 491 {
 492   bool kill_emacs = (CONSP (event) && CONSP (XCDR (event))
 493                      && EQ (Qt, XCAR (XCDR (event))));
 494
 495   /* Check doing_interact so that we don't do anything if someone called
 496      this at the wrong time. */
 497   if (doing_interact && ! kill_emacs)
 498     {
 499       bool cancel_shutdown = ! NILP (call0 (intern ("emacs-session-save")));
 500
 501       SmcInteractDone (smc_conn, cancel_shutdown);
 502       SmcSaveYourselfDone (smc_conn, True);
 503
 504       doing_interact = false;
 505     }
 506   else if (kill_emacs)
 507     {
 508       /* We should not do user interaction here, but it is not easy to
 509          prevent.  Fix this in next version.  */
 510       Fkill_emacs (Qnil);
 511
 512 #if false
 513       /* This will not be reached, but we want kill-emacs-hook to be run.  */
 514       SmcCloseConnection (smc_conn, 0, 0);
 515       ice_connection_closed ();
 516 #endif
 517     }
 518
 519   return Qnil;
 520 }
 521
 522
 523 \f
 524 /***********************************************************************
 525                             Initialization
 526  ***********************************************************************/
 527 void
 528 syms_of_xsmfns (void)
 529 {
 530   DEFVAR_LISP ("x-session-id", Vx_session_id,
 531     doc: /* The session id Emacs got from the session manager for this session.
 532 Changing the value does not change the session id used by Emacs.
 533 The value is nil if no session manager is running.
 534 See also `x-session-previous-id', `emacs-save-session-functions',
 535 `emacs-session-save' and `emacs-session-restore'." */);
 536   Vx_session_id = Qnil;
 537
 538   DEFVAR_LISP ("x-session-previous-id", Vx_session_previous_id,
 539     doc: /* The previous session id Emacs got from session manager.
 540 If Emacs is running on a window system that has a session manager, the
 541 session manager gives Emacs a session id.  It is feasible for Emacs Lisp
 542 code to use the session id to save configuration in, for example, a file
 543 with a file name based on the session id.  If Emacs is running when the
 544 window system is shut down, the session manager remembers that Emacs was
 545 running and saves the session id Emacs had.
 546
 547 When the window system is started again, the session manager restarts
 548 Emacs and hands Emacs the session id it had the last time it was
 549 running.  This is now the previous session id and the value of this
 550 variable.  If configuration was saved in a file as stated above, the
 551 previous session id shall be used to reconstruct the file name.
 552
 553 The session id Emacs has while it is running is in the variable
 554 `x-session-id'.  The value of this variable and `x-session-id' may be the
 555 same, depending on how the session manager works.
 556
 557 See also `emacs-save-session-functions', `emacs-session-save' and
 558 `emacs-session-restore'." */);
 559   Vx_session_previous_id = Qnil;
 560
 561   defsubr (&Shandle_save_session);
 562 }
 563
 564 #endif /* HAVE_X_SM */