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 <errno.h>
  32 #include <stdio.h>
  33
  34 #include "lisp.h"
  35 #include "frame.h"
  36 #include "termhooks.h"
  37 #include "xterm.h"
  38 #include "process.h"
  39 #include "keyboard.h"
  40
  41 #if defined USE_GTK && !defined HAVE_GTK3
  42 #define gdk_x11_set_sm_client_id(w) gdk_set_sm_client_id (w)
  43 #endif
  44
  45 /* This is the event used when SAVE_SESSION_EVENT occurs.  */
  46
  47 static struct input_event emacs_event;
  48
  49 /* The descriptor that we use to check for data from the session manager.  */
  50
  51 static int ice_fd = -1;
  52
  53 /* A flag that says if we are in shutdown interactions or not.  */
  54
  55 static bool doing_interact;
  56
  57 /* The session manager object for the session manager connection.  */
  58
  59 static SmcConn smc_conn;
  60
  61 /* The client session id for this session.  */
  62
  63 static char *client_id;
  64
  65 /* The full path name to the Emacs program.  */
  66
  67 static char *emacs_program;
  68
  69 /* The option we tell the session manager to start Emacs with when
  70    restarting Emacs.  The client_id is appended.  */
  71
  72 #define SMID_OPT "--smid="
  73
  74
  75 /* The option to start Emacs without the splash screen when
  76    restarting Emacs.  */
  77
  78 static char NOSPLASH_OPT[] = "--no-splash";
  79
  80 /* The option to make Emacs start in the given directory.  */
  81
  82 #define CHDIR_OPT "--chdir="
  83
  84 static void
  85 ice_connection_closed (void)
  86 {
  87   if (ice_fd >= 0)
  88     delete_read_fd (ice_fd);
  89   ice_fd = -1;
  90 }
  91
  92
  93 /* Handle any messages from the session manager.  If no connection is
  94    open to a session manager, just return.  */
  95
  96 static void
  97 x_session_check_input (int fd, void *data)
  98 {
  99   int ret;
 100
 101   if (ice_fd == -1) return;
 102
 103   /* Reset this so wo can check kind after callbacks have been called by
 104      IceProcessMessages.  The smc_interact_CB sets the kind to
 105      SAVE_SESSION_EVENT, but we don't know beforehand if that callback
 106      will be called.  */
 107   emacs_event.kind = NO_EVENT;
 108
 109   ret = IceProcessMessages (SmcGetIceConnection (smc_conn), 0, 0);
 110   if (ret != IceProcessMessagesSuccess)
 111     {
 112       /* Either IO error or Connection closed.  */
 113       if (ret == IceProcessMessagesIOError)
 114         IceCloseConnection (SmcGetIceConnection (smc_conn));
 115
 116       ice_connection_closed ();
 117     }
 118
 119   /* Check if smc_interact_CB was called and we shall generate a
 120      SAVE_SESSION_EVENT.  */
 121   if (emacs_event.kind != NO_EVENT)
 122     kbd_buffer_store_event (&emacs_event);
 123 }
 124
 125 /* Return true if we have a connection to a session manager.  */
 126
 127 bool
 128 x_session_have_connection (void)
 129 {
 130   return ice_fd != -1;
 131 }
 132
 133 /* This is called when the session manager says it is OK to interact with the
 134    user.  Here we set the kind to SAVE_SESSION_EVENT so an event is generated.
 135    Then lisp code can interact with the user.  */
 136
 137 static void
 138 smc_interact_CB (SmcConn smcConn, SmPointer clientData)
 139 {
 140   doing_interact = true;
 141   emacs_event.kind = SAVE_SESSION_EVENT;
 142   emacs_event.arg = Qnil;
 143 }
 144
 145 /* This is called when the session manager tells us to save ourselves.
 146    We set the required properties so the session manager can restart us,
 147    plus the current working directory property (not mandatory) so we
 148    are started in the correct directory.
 149
 150    If this is a shutdown and we can request to interact with the user,
 151    we do so, because we don't know what the lisp code might do.  */
 152
 153 static void
 154 smc_save_yourself_CB (SmcConn smcConn,
 155                       SmPointer clientData,
 156                       int saveType,
 157                       Bool shutdown,
 158                       int interactStyle,
 159                       Bool fast)
 160 {
 161 #define NR_PROPS 5
 162
 163   SmProp *props[NR_PROPS];
 164   SmProp prop_ptr[NR_PROPS];
 165
 166   SmPropValue values[20], *vp;
 167   int val_idx = 0, vp_idx = 0;
 168   int props_idx = 0;
 169   int i;
 170   char *smid_opt, *chdir_opt = NULL;
 171   Lisp_Object user_login_name = Fuser_login_name (Qnil);
 172
 173   // Must have these.
 174   if (! STRINGP (Vinvocation_name) || ! STRINGP (user_login_name))
 175     return;
 176
 177   /* How to start a new instance of Emacs.  */
 178   props[props_idx] = &prop_ptr[props_idx];
 179   props[props_idx]->name = xstrdup (SmCloneCommand);
 180   props[props_idx]->type = xstrdup (SmLISTofARRAY8);
 181   props[props_idx]->num_vals = 1;
 182   props[props_idx]->vals = &values[val_idx++];
 183   props[props_idx]->vals[0].length = strlen (emacs_program);
 184   props[props_idx]->vals[0].value = emacs_program;
 185   ++props_idx;
 186
 187   /* The name of the program.  */
 188   props[props_idx] = &prop_ptr[props_idx];
 189   props[props_idx]->name = xstrdup (SmProgram);
 190   props[props_idx]->type = xstrdup (SmARRAY8);
 191   props[props_idx]->num_vals = 1;
 192   props[props_idx]->vals = &values[val_idx++];
 193   props[props_idx]->vals[0].length = SBYTES (Vinvocation_name);
 194   props[props_idx]->vals[0].value = SDATA (Vinvocation_name);
 195   ++props_idx;
 196
 197   /* User id.  */
 198   props[props_idx] = &prop_ptr[props_idx];
 199   props[props_idx]->name = xstrdup (SmUserID);
 200   props[props_idx]->type = xstrdup (SmARRAY8);
 201   props[props_idx]->num_vals = 1;
 202   props[props_idx]->vals = &values[val_idx++];
 203   props[props_idx]->vals[0].length = SBYTES (user_login_name);
 204   props[props_idx]->vals[0].value = SDATA (user_login_name);
 205   ++props_idx;
 206
 207   char *cwd = get_current_dir_name ();
 208   if (cwd)
 209     {
 210       props[props_idx] = &prop_ptr[props_idx];
 211       props[props_idx]->name = xstrdup (SmCurrentDirectory);
 212       props[props_idx]->type = xstrdup (SmARRAY8);
 213       props[props_idx]->num_vals = 1;
 214       props[props_idx]->vals = &values[val_idx++];
 215       props[props_idx]->vals[0].length = strlen (cwd);
 216       props[props_idx]->vals[0].value = cwd;
 217       ++props_idx;
 218     }
 219
 220
 221   /* How to restart Emacs.  */
 222   props[props_idx] = &prop_ptr[props_idx];
 223   props[props_idx]->name = xstrdup (SmRestartCommand);
 224   props[props_idx]->type = xstrdup (SmLISTofARRAY8);
 225   /* /path/to/emacs, --smid=xxx --no-splash --chdir=dir ... */
 226   if (INT_MAX - 3 < initial_argc)
 227     memory_full (SIZE_MAX);
 228   i = 3 + initial_argc;
 229   props[props_idx]->num_vals = i;
 230   vp = xnmalloc (i, sizeof *vp);
 231   props[props_idx]->vals = vp;
 232   props[props_idx]->vals[vp_idx].length = strlen (emacs_program);
 233   props[props_idx]->vals[vp_idx++].value = emacs_program;
 234
 235   smid_opt = xmalloc (strlen (SMID_OPT) + strlen (client_id) + 1);
 236   strcpy (stpcpy (smid_opt, SMID_OPT), client_id);
 237
 238   props[props_idx]->vals[vp_idx].length = strlen (smid_opt);
 239   props[props_idx]->vals[vp_idx++].value = smid_opt;
 240
 241   props[props_idx]->vals[vp_idx].length = strlen (NOSPLASH_OPT);
 242   props[props_idx]->vals[vp_idx++].value = NOSPLASH_OPT;
 243
 244   if (cwd)
 245     {
 246       chdir_opt = xmalloc (strlen (CHDIR_OPT) + strlen (cwd) + 1);
 247       strcpy (stpcpy (chdir_opt, CHDIR_OPT), cwd);
 248
 249       props[props_idx]->vals[vp_idx].length = strlen (chdir_opt);
 250       props[props_idx]->vals[vp_idx++].value = chdir_opt;
 251     }
 252
 253   for (i = 1; i < initial_argc; ++i)
 254     {
 255       props[props_idx]->vals[vp_idx].length = strlen (initial_argv[i]);
 256       props[props_idx]->vals[vp_idx++].value = initial_argv[i];
 257     }
 258
 259   ++props_idx;
 260
 261   SmcSetProperties (smcConn, props_idx, props);
 262
 263   xfree (smid_opt);
 264   xfree (chdir_opt);
 265   xfree (cwd);
 266   xfree (vp);
 267
 268   for (i = 0; i < props_idx; ++i)
 269     {
 270       xfree (props[i]->type);
 271       xfree (props[i]->name);
 272     }
 273
 274   /* See if we maybe shall interact with the user.  */
 275   if (interactStyle != SmInteractStyleAny
 276       || ! shutdown
 277       || saveType == SmSaveLocal
 278       || ! SmcInteractRequest (smcConn, SmDialogNormal, smc_interact_CB, 0))
 279     {
 280       /* No interaction, we are done saving ourself.  */
 281       SmcSaveYourselfDone (smcConn, True);
 282     }
 283 }
 284
 285 /* According to the SM specification, this shall close the connection.  */
 286
 287 static void
 288 smc_die_CB (SmcConn smcConn, SmPointer clientData)
 289 {
 290   emacs_event.kind = SAVE_SESSION_EVENT;
 291   emacs_event.arg = Qt;
 292 }
 293
 294 /* We don't use the next two but they are mandatory, leave them empty.
 295    According to the SM specification, we should not interact with the
 296    user between smc_save_yourself_CB is called and until smc_save_complete_CB
 297    is called.  It seems like a lot of job to implement this and it doesn't
 298    even seem necessary.  */
 299
 300 static void
 301 smc_save_complete_CB (SmcConn smcConn, SmPointer clientData)
 302 {
 303   /* Empty */
 304 }
 305
 306 static void
 307 smc_shutdown_cancelled_CB (SmcConn smcConn, SmPointer clientData)
 308 {
 309   /* Empty */
 310 }
 311
 312 /* Error handlers for SM and ICE.  We don't want to exit Emacs just
 313    because there is some error in the session management.  */
 314
 315 static void
 316 smc_error_handler (SmcConn smcConn,
 317                    Bool swap,
 318                    int offendingMinorOpcode,
 319                    unsigned long offendingSequence,
 320                    int errorClass,
 321                    int severity,
 322                    SmPointer values)
 323 {
 324   /* Empty  */
 325 }
 326
 327 static void
 328 ice_error_handler (IceConn iceConn,
 329                    Bool swap,
 330                    int offendingMinorOpcode,
 331                    unsigned long offendingSequence,
 332                    int errorClass,
 333                    int severity,
 334                    IcePointer values)
 335 {
 336   /* Empty  */
 337 }
 338
 339
 340 static void
 341 ice_io_error_handler (IceConn iceConn)
 342 {
 343   /* Connection probably gone.  */
 344   ice_connection_closed ();
 345 }
 346
 347 /* This is called when the ICE connection is created or closed.  The SM library
 348    uses ICE as it transport protocol.  */
 349
 350 static void
 351 ice_conn_watch_CB (IceConn iceConn, IcePointer clientData,
 352                    int opening, IcePointer *watchData)
 353 {
 354   if (! opening)
 355     {
 356       ice_connection_closed ();
 357       return;
 358     }
 359
 360   ice_fd = IceConnectionNumber (iceConn);
 361   add_read_fd (ice_fd, x_session_check_input, NULL);
 362 }
 363
 364 /* Create the client leader window.  */
 365
 366 #ifndef USE_GTK
 367 static void
 368 create_client_leader_window (struct x_display_info *dpyinfo, char *client_ID)
 369 {
 370   Window w;
 371   XClassHint class_hints;
 372
 373   w = XCreateSimpleWindow (dpyinfo->display,
 374                            dpyinfo->root_window,
 375                            -1, -1, 1, 1,
 376                            CopyFromParent, CopyFromParent, CopyFromParent);
 377
 378   validate_x_resource_name ();
 379   class_hints.res_name = SSDATA (Vx_resource_name);
 380   class_hints.res_class = SSDATA (Vx_resource_class);
 381   XSetClassHint (dpyinfo->display, w, &class_hints);
 382   XStoreName (dpyinfo->display, w, class_hints.res_name);
 383
 384   XChangeProperty (dpyinfo->display, w, dpyinfo->Xatom_SM_CLIENT_ID,
 385                    XA_STRING, 8, PropModeReplace,
 386                    (unsigned char *) client_ID, strlen (client_ID));
 387
 388   dpyinfo->client_leader_window = w;
 389 }
 390 #endif /* ! USE_GTK */
 391
 392
 393 /* Try to open a connection to the session manager.  */
 394
 395 void
 396 x_session_initialize (struct x_display_info *dpyinfo)
 397 {
 398 #define SM_ERRORSTRING_LEN 512
 399   char errorstring[SM_ERRORSTRING_LEN];
 400   char *previous_id = NULL;
 401   SmcCallbacks callbacks;
 402   ptrdiff_t name_len = 0;
 403
 404   /* libSM seems to crash if pwd is missing - see bug#18851.  */
 405   if (! get_current_dir_name ())
 406     {
 407       fprintf (stderr, "Disabling session management due to pwd error: %s\n",
 408                emacs_strerror (errno));
 409       return;
 410     }
 411
 412   ice_fd = -1;
 413   doing_interact = false;
 414
 415   /* Check if we where started by the session manager.  If so, we will
 416      have a previous id.  */
 417   if (STRINGP (Vx_session_previous_id))
 418     previous_id = SSDATA (Vx_session_previous_id);
 419
 420   /* Construct the path to the Emacs program.  */
 421   if (STRINGP (Vinvocation_directory))
 422     name_len += SBYTES (Vinvocation_directory);
 423   if (STRINGP (Vinvocation_name))
 424     name_len += SBYTES (Vinvocation_name);
 425
 426   /* This malloc will not be freed, but it is only done once, and hopefully
 427      not very large   */
 428   emacs_program = xmalloc (name_len + 1);
 429   char *z = emacs_program;
 430
 431   if (STRINGP (Vinvocation_directory))
 432     z = lispstpcpy (z, Vinvocation_directory);
 433   if (STRINGP (Vinvocation_name))
 434     lispstpcpy (z, Vinvocation_name);
 435
 436   /* The SM protocol says all callbacks are mandatory, so set up all
 437      here and in the mask passed to SmcOpenConnection.  */
 438   callbacks.save_yourself.callback = smc_save_yourself_CB;
 439   callbacks.save_yourself.client_data = 0;
 440   callbacks.die.callback = smc_die_CB;
 441   callbacks.die.client_data = 0;
 442   callbacks.save_complete.callback = smc_save_complete_CB;
 443   callbacks.save_complete.client_data = 0;
 444   callbacks.shutdown_cancelled.callback = smc_shutdown_cancelled_CB;
 445   callbacks.shutdown_cancelled.client_data = 0;
 446
 447   /* Set error handlers.  */
 448   SmcSetErrorHandler (smc_error_handler);
 449   IceSetErrorHandler (ice_error_handler);
 450   IceSetIOErrorHandler (ice_io_error_handler);
 451
 452   /* Install callback for when connection status changes.  */
 453   IceAddConnectionWatch (ice_conn_watch_CB, 0);
 454
 455   /* Open the connection to the session manager.  A failure is not
 456      critical, it usually means that no session manager is running.
 457      The errorstring is here for debugging.  */
 458   smc_conn = SmcOpenConnection (NULL, NULL, 1, 0,
 459                                 (SmcSaveYourselfProcMask|
 460                                  SmcDieProcMask|
 461                                  SmcSaveCompleteProcMask|
 462                                  SmcShutdownCancelledProcMask),
 463                                 &callbacks,
 464                                 previous_id,
 465                                 &client_id,
 466                                 SM_ERRORSTRING_LEN,
 467                                 errorstring);
 468
 469   if (smc_conn != 0)
 470     {
 471       Vx_session_id = build_string (client_id);
 472
 473 #ifdef USE_GTK
 474       /* GTK creates a leader window by itself, but we need to tell
 475          it about our client_id.  */
 476       gdk_x11_set_sm_client_id (client_id);
 477 #else
 478       create_client_leader_window (dpyinfo, client_id);
 479 #endif
 480     }
 481 }
 482
 483 /* Ensure that the session manager is not contacted again. */
 484
 485 void
 486 x_session_close (void)
 487 {
 488   ice_connection_closed ();
 489 }
 490
 491
 492 DEFUN ("handle-save-session", Fhandle_save_session,
 493        Shandle_save_session, 1, 1, "e",
 494        doc: /* Handle the save_yourself event from a session manager.
 495 A session manager can tell Emacs that the window system is shutting down
 496 by sending Emacs a save_yourself message.  Emacs executes this function when
 497 such an event occurs.  This function then executes `emacs-session-save'.
 498 After that, this function informs the session manager that it can continue
 499 or abort shutting down the window system depending on the return value
 500 from `emacs-session-save'  If the return value is non-nil the session manager
 501 is told to abort the window system shutdown.
 502
 503 Do not call this function yourself. */)
 504   (Lisp_Object event)
 505 {
 506   bool kill_emacs = (CONSP (event) && CONSP (XCDR (event))
 507                      && EQ (Qt, XCAR (XCDR (event))));
 508
 509   /* Check doing_interact so that we don't do anything if someone called
 510      this at the wrong time. */
 511   if (doing_interact && ! kill_emacs)
 512     {
 513       bool cancel_shutdown = ! NILP (call0 (intern ("emacs-session-save")));
 514
 515       SmcInteractDone (smc_conn, cancel_shutdown);
 516       SmcSaveYourselfDone (smc_conn, True);
 517
 518       doing_interact = false;
 519     }
 520   else if (kill_emacs)
 521     {
 522       /* We should not do user interaction here, but it is not easy to
 523          prevent.  Fix this in next version.  */
 524       Fkill_emacs (Qnil);
 525
 526 #if false
 527       /* This will not be reached, but we want kill-emacs-hook to be run.  */
 528       SmcCloseConnection (smc_conn, 0, 0);
 529       ice_connection_closed ();
 530 #endif
 531     }
 532
 533   return Qnil;
 534 }
 535
 536
 537 \f
 538 /***********************************************************************
 539                             Initialization
 540  ***********************************************************************/
 541 void
 542 syms_of_xsmfns (void)
 543 {
 544   DEFVAR_LISP ("x-session-id", Vx_session_id,
 545     doc: /* The session id Emacs got from the session manager for this session.
 546 Changing the value does not change the session id used by Emacs.
 547 The value is nil if no session manager is running.
 548 See also `x-session-previous-id', `emacs-save-session-functions',
 549 `emacs-session-save' and `emacs-session-restore'." */);
 550   Vx_session_id = Qnil;
 551
 552   DEFVAR_LISP ("x-session-previous-id", Vx_session_previous_id,
 553     doc: /* The previous session id Emacs got from session manager.
 554 If Emacs is running on a window system that has a session manager, the
 555 session manager gives Emacs a session id.  It is feasible for Emacs Lisp
 556 code to use the session id to save configuration in, for example, a file
 557 with a file name based on the session id.  If Emacs is running when the
 558 window system is shut down, the session manager remembers that Emacs was
 559 running and saves the session id Emacs had.
 560
 561 When the window system is started again, the session manager restarts
 562 Emacs and hands Emacs the session id it had the last time it was
 563 running.  This is now the previous session id and the value of this
 564 variable.  If configuration was saved in a file as stated above, the
 565 previous session id shall be used to reconstruct the file name.
 566
 567 The session id Emacs has while it is running is in the variable
 568 `x-session-id'.  The value of this variable and `x-session-id' may be the
 569 same, depending on how the session manager works.
 570
 571 See also `emacs-save-session-functions', `emacs-session-save' and
 572 `emacs-session-restore'." */);
 573   Vx_session_previous_id = Qnil;
 574
 575   defsubr (&Shandle_save_session);
 576 }
 577
 578 #endif /* HAVE_X_SM */