summaryrefslogtreecommitdiff
path: root/widget/xremoteclient/XRemoteClient.cpp
blob: c4567f3cb9ab35f857a1802ba675164f03119c0c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:expandtab:shiftwidth=2:tabstop=8:
 */
/* vim:set ts=8 sw=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/ArrayUtils.h"
#include "mozilla/Sprintf.h"
#include "XRemoteClient.h"
#include "prmem.h"
#include "plstr.h"
#include "prsystem.h"
#include "mozilla/Logging.h"
#include "prenv.h"
#include "prdtoa.h"
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <strings.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <limits.h>
#include <X11/Xatom.h>

#define MOZILLA_VERSION_PROP   "_MOZILLA_VERSION"
#define MOZILLA_LOCK_PROP      "_MOZILLA_LOCK"
#define MOZILLA_COMMANDLINE_PROP "_MOZILLA_COMMANDLINE"
#define MOZILLA_RESPONSE_PROP  "_MOZILLA_RESPONSE"
#define MOZILLA_USER_PROP      "_MOZILLA_USER"
#define MOZILLA_PROFILE_PROP   "_MOZILLA_PROFILE"
#define MOZILLA_PROGRAM_PROP   "_MOZILLA_PROGRAM"

#ifdef IS_BIG_ENDIAN
#define TO_LITTLE_ENDIAN32(x) \
    ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \
    (((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24))
#else
#define TO_LITTLE_ENDIAN32(x) (x)
#endif
    
#ifndef MAX_PATH
#ifdef PATH_MAX
#define MAX_PATH PATH_MAX
#else
#define MAX_PATH 1024
#endif
#endif

using mozilla::LogLevel;

static PRLogModuleInfo *sRemoteLm = nullptr;

static int (*sOldHandler)(Display *, XErrorEvent *);
static bool sGotBadWindow;

XRemoteClient::XRemoteClient()
{
  mDisplay = 0;
  mInitialized = false;
  mMozVersionAtom = 0;
  mMozLockAtom = 0;
  mMozCommandLineAtom = 0;
  mMozResponseAtom = 0;
  mMozWMStateAtom = 0;
  mMozUserAtom = 0;
  mMozProfileAtom = 0;
  mMozProgramAtom = 0;
  mLockData = 0;
  if (!sRemoteLm)
    sRemoteLm = PR_NewLogModule("XRemoteClient");
  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("XRemoteClient::XRemoteClient"));
}

XRemoteClient::~XRemoteClient()
{
  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("XRemoteClient::~XRemoteClient"));
  if (mInitialized)
    Shutdown();
}

// Minimize the roundtrips to the X-server
static const char *XAtomNames[] = {
  MOZILLA_VERSION_PROP,
  MOZILLA_LOCK_PROP,
  MOZILLA_RESPONSE_PROP,
  "WM_STATE",
  MOZILLA_USER_PROP,
  MOZILLA_PROFILE_PROP,
  MOZILLA_PROGRAM_PROP,
  MOZILLA_COMMANDLINE_PROP
};
static Atom XAtoms[MOZ_ARRAY_LENGTH(XAtomNames)];

nsresult
XRemoteClient::Init()
{
  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("XRemoteClient::Init"));

  if (mInitialized)
    return NS_OK;

  // try to open the display
  mDisplay = XOpenDisplay(0);
  if (!mDisplay)
    return NS_ERROR_FAILURE;

  // get our atoms
  XInternAtoms(mDisplay, const_cast<char**>(XAtomNames),
               MOZ_ARRAY_LENGTH(XAtomNames), False, XAtoms);

  int i = 0;
  mMozVersionAtom  = XAtoms[i++];
  mMozLockAtom     = XAtoms[i++];
  mMozResponseAtom = XAtoms[i++];
  mMozWMStateAtom  = XAtoms[i++];
  mMozUserAtom     = XAtoms[i++];
  mMozProfileAtom  = XAtoms[i++];
  mMozProgramAtom  = XAtoms[i++];
  mMozCommandLineAtom = XAtoms[i++];

  mInitialized = true;

  return NS_OK;
}

void
XRemoteClient::Shutdown (void)
{
  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("XRemoteClient::Shutdown"));

  if (!mInitialized)
    return;

  // shut everything down
  XCloseDisplay(mDisplay);
  mDisplay = 0;
  mInitialized = false;
  if (mLockData) {
    free(mLockData);
    mLockData = 0;
  }
}

static int
HandleBadWindow(Display *display, XErrorEvent *event)
{
  if (event->error_code == BadWindow) {
    sGotBadWindow = true;
    return 0; // ignored
  }
  else {
    return (*sOldHandler)(display, event);
  }
}

nsresult
XRemoteClient::SendCommandLine (const char *aProgram, const char *aUsername,
                                const char *aProfile,
                                int32_t argc, char **argv,
                                const char* aDesktopStartupID,
                                char **aResponse, bool *aWindowFound)
{
  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("XRemoteClient::SendCommandLine"));

  *aWindowFound = false;

  // FindBestWindow() iterates down the window hierarchy, so catch X errors
  // when windows get destroyed before being accessed.
  sOldHandler = XSetErrorHandler(HandleBadWindow);

  Window w = FindBestWindow(aProgram, aUsername, aProfile);

  nsresult rv = NS_OK;

  if (w) {
    // ok, let the caller know that we at least found a window.
    *aWindowFound = true;

    // Ignore BadWindow errors up to this point.  The last request from
    // FindBestWindow() was a synchronous XGetWindowProperty(), so no need to
    // Sync.  Leave the error handler installed to detect if w gets destroyed.
    sGotBadWindow = false;

    // make sure we get the right events on that window
    XSelectInput(mDisplay, w,
                 (PropertyChangeMask|StructureNotifyMask));

    bool destroyed = false;

    // get the lock on the window
    rv = GetLock(w, &destroyed);

    if (NS_SUCCEEDED(rv)) {
      // send our command
      rv = DoSendCommandLine(w, argc, argv, aDesktopStartupID, aResponse,
                             &destroyed);

      // if the window was destroyed, don't bother trying to free the
      // lock.
      if (!destroyed)
          FreeLock(w); // doesn't really matter what this returns

    }
  }

  XSetErrorHandler(sOldHandler);

  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("SendCommandInternal returning 0x%x\n", rv));

  return rv;
}

Window
XRemoteClient::CheckWindow(Window aWindow)
{
  Atom type = None;
  int  format;
  unsigned long nitems, bytesafter;
  unsigned char *data;
  Window innerWindow;

  XGetWindowProperty(mDisplay, aWindow, mMozWMStateAtom,
		     0, 0, False, AnyPropertyType,
		     &type, &format, &nitems, &bytesafter, &data);

  if (type) {
    XFree(data);
    return aWindow;
  }

  // didn't find it here so check the children of this window
  innerWindow = CheckChildren(aWindow);

  if (innerWindow)
    return innerWindow;

  return aWindow;
}

Window
XRemoteClient::CheckChildren(Window aWindow)
{
  Window root, parent;
  Window *children;
  unsigned int nchildren;
  unsigned int i;
  Atom type = None;
  int format;
  unsigned long nitems, after;
  unsigned char *data;
  Window retval = None;
  
  if (!XQueryTree(mDisplay, aWindow, &root, &parent, &children,
		  &nchildren))
    return None;
  
  // scan the list first before recursing into the list of windows
  // which can get quite deep.
  for (i=0; !retval && (i < nchildren); i++) {
    XGetWindowProperty(mDisplay, children[i], mMozWMStateAtom,
		       0, 0, False, AnyPropertyType, &type, &format,
		       &nitems, &after, &data);
    if (type) {
      XFree(data);
      retval = children[i];
    }
  }

  // otherwise recurse into the list
  for (i=0; !retval && (i < nchildren); i++) {
    retval = CheckChildren(children[i]);
  }

  if (children)
    XFree((char *)children);

  return retval;
}

nsresult
XRemoteClient::GetLock(Window aWindow, bool *aDestroyed)
{
  bool locked = false;
  bool waited = false;
  *aDestroyed = false;

  nsresult rv = NS_OK;

  if (!mLockData) {
    
    char pidstr[32];
    char sysinfobuf[SYS_INFO_BUFFER_LENGTH];
    SprintfLiteral(pidstr, "pid%d@", getpid());
    PRStatus status;
    status = PR_GetSystemInfo(PR_SI_HOSTNAME, sysinfobuf,
			      SYS_INFO_BUFFER_LENGTH);
    if (status != PR_SUCCESS) {
      return NS_ERROR_FAILURE;
    }
    
    // allocate enough space for the string plus the terminating
    // char
    mLockData = (char *)malloc(strlen(pidstr) + strlen(sysinfobuf) + 1);
    if (!mLockData)
      return NS_ERROR_OUT_OF_MEMORY;

    strcpy(mLockData, pidstr);
    if (!strcat(mLockData, sysinfobuf))
      return NS_ERROR_FAILURE;
  }

  do {
    int result;
    Atom actual_type;
    int actual_format;
    unsigned long nitems, bytes_after;
    unsigned char *data = 0;

    XGrabServer(mDisplay);

    result = XGetWindowProperty (mDisplay, aWindow, mMozLockAtom,
				 0, (65536 / sizeof (long)),
				 False, /* don't delete */
				 XA_STRING,
				 &actual_type, &actual_format,
				 &nitems, &bytes_after,
				 &data);

    // aWindow may have been destroyed before XSelectInput was processed, in
    // which case there may not be any DestroyNotify event in the queue to
    // tell us.  XGetWindowProperty() was synchronous so error responses have
    // now been processed, setting sGotBadWindow.
    if (sGotBadWindow) {
      *aDestroyed = true;
      rv = NS_ERROR_FAILURE;
    }
    else if (result != Success || actual_type == None) {
      /* It's not now locked - lock it. */
      XChangeProperty (mDisplay, aWindow, mMozLockAtom, XA_STRING, 8,
		       PropModeReplace,
		       (unsigned char *)mLockData,
		       strlen(mLockData));
      locked = True;
    }

    XUngrabServer(mDisplay);
    XFlush(mDisplay); // ungrab now!

    if (!locked && !NS_FAILED(rv)) {
      /* We tried to grab the lock this time, and failed because someone
	 else is holding it already.  So, wait for a PropertyDelete event
	 to come in, and try again. */
      MOZ_LOG(sRemoteLm, LogLevel::Debug, 
	     ("window 0x%x is locked by %s; waiting...\n",
	      (unsigned int) aWindow, data));
      waited = True;
      while (1) {
	XEvent event;
	int select_retval;
	fd_set select_set;
	struct timeval delay;
	delay.tv_sec = 10;
	delay.tv_usec = 0;

	FD_ZERO(&select_set);
	// add the x event queue to the select set
	FD_SET(ConnectionNumber(mDisplay), &select_set);
	select_retval = select(ConnectionNumber(mDisplay) + 1,
			       &select_set, nullptr, nullptr, &delay);
	// did we time out?
	if (select_retval == 0) {
	  MOZ_LOG(sRemoteLm, LogLevel::Debug, ("timed out waiting for window\n"));
          rv = NS_ERROR_FAILURE;
          break;
	}
	MOZ_LOG(sRemoteLm, LogLevel::Debug, ("xevent...\n"));
	XNextEvent (mDisplay, &event);
	if (event.xany.type == DestroyNotify &&
	    event.xdestroywindow.window == aWindow) {
	  *aDestroyed = true;
          rv = NS_ERROR_FAILURE;
          break;
	}
	else if (event.xany.type == PropertyNotify &&
		 event.xproperty.state == PropertyDelete &&
		 event.xproperty.window == aWindow &&
		 event.xproperty.atom == mMozLockAtom) {
	  /* Ok!  Someone deleted their lock, so now we can try
	     again. */
	  MOZ_LOG(sRemoteLm, LogLevel::Debug,
		 ("(0x%x unlocked, trying again...)\n",
		  (unsigned int) aWindow));
		  break;
	}
      }
    }
    if (data)
      XFree(data);
  } while (!locked && !NS_FAILED(rv));

  if (waited && locked) {
    MOZ_LOG(sRemoteLm, LogLevel::Debug, ("obtained lock.\n"));
  } else if (*aDestroyed) {
    MOZ_LOG(sRemoteLm, LogLevel::Debug,
           ("window 0x%x unexpectedly destroyed.\n",
            (unsigned int) aWindow));
  }

  return rv;
}

Window
XRemoteClient::FindBestWindow(const char *aProgram, const char *aUsername,
                              const char *aProfile)
{
  Window root = RootWindowOfScreen(DefaultScreenOfDisplay(mDisplay));
  Window bestWindow = 0;
  Window root2, parent, *kids;
  unsigned int nkids;

  // Get a list of the children of the root window, walk the list
  // looking for the best window that fits the criteria.
  if (!XQueryTree(mDisplay, root, &root2, &parent, &kids, &nkids)) {
    MOZ_LOG(sRemoteLm, LogLevel::Debug,
           ("XQueryTree failed in XRemoteClient::FindBestWindow"));
    return 0;
  }

  if (!(kids && nkids)) {
    MOZ_LOG(sRemoteLm, LogLevel::Debug, ("root window has no children"));
    return 0;
  }

  // We'll walk the list of windows looking for a window that best
  // fits the criteria here.

  for (unsigned int i = 0; i < nkids; i++) {
    Atom type;
    int format;
    unsigned long nitems, bytesafter;
    unsigned char *data_return = 0;
    Window w;
    w = kids[i];
    // find the inner window with WM_STATE on it
    w = CheckWindow(w);

    int status = XGetWindowProperty(mDisplay, w, mMozVersionAtom,
                                    0, (65536 / sizeof (long)),
                                    False, XA_STRING,
                                    &type, &format, &nitems, &bytesafter,
                                    &data_return);

    if (!data_return)
      continue;

    double version = PR_strtod((char*) data_return, nullptr);
    XFree(data_return);

    if (!(version >= 5.1 && version < 6))
      continue;

    data_return = 0;

    if (status != Success || type == None)
      continue;

    // If someone passed in a program name, check it against this one
    // unless it's "any" in which case, we don't care.  If someone did
    // pass in a program name and this window doesn't support that
    // protocol, we don't include it in our list.
    if (aProgram && strcmp(aProgram, "any")) {
        status = XGetWindowProperty(mDisplay, w, mMozProgramAtom,
                                    0, (65536 / sizeof(long)),
                                    False, XA_STRING,
                                    &type, &format, &nitems, &bytesafter,
                                    &data_return);
        
        // If the return name is not the same as what someone passed in,
        // we don't want this window.
        if (data_return) {
            if (strcmp(aProgram, (const char *)data_return)) {
                XFree(data_return);
                continue;
            }

            // This is actually the success condition.
            XFree(data_return);
        }
        else {
            // Doesn't support the protocol, even though the user
            // requested it.  So we're not going to use this window.
            continue;
        }
    }

    // Check to see if it has the user atom on that window.  If there
    // is then we need to make sure that it matches what we have.
    const char *username;
    if (aUsername) {
      username = aUsername;
    }
    else {
      username = PR_GetEnv("LOGNAME");
    }

    if (username) {
        status = XGetWindowProperty(mDisplay, w, mMozUserAtom,
                                    0, (65536 / sizeof(long)),
                                    False, XA_STRING,
                                    &type, &format, &nitems, &bytesafter,
                                    &data_return);

        // if there's a username compare it with what we have
        if (data_return) {
            // If the IDs aren't equal, we don't want this window.
            if (strcmp(username, (const char *)data_return)) {
                XFree(data_return);
                continue;
            }

            XFree(data_return);
        }
    }

    // Check to see if there's a profile name on this window.  If
    // there is, then we need to make sure it matches what someone
    // passed in.
    if (aProfile) {
        status = XGetWindowProperty(mDisplay, w, mMozProfileAtom,
                                    0, (65536 / sizeof(long)),
                                    False, XA_STRING,
                                    &type, &format, &nitems, &bytesafter,
                                    &data_return);

        // If there's a profile compare it with what we have
        if (data_return) {
            // If the profiles aren't equal, we don't want this window.
            if (strcmp(aProfile, (const char *)data_return)) {
                XFree(data_return);
                continue;
            }

            XFree(data_return);
        }
    }

    // Check to see if the window supports the new command-line passing
    // protocol, if that is requested.

    // If we got this far, this is the best window.  It passed
    // all the tests.
    bestWindow = w;
    break;
  }

  if (kids)
    XFree((char *) kids);

  return bestWindow;
}

nsresult
XRemoteClient::FreeLock(Window aWindow)
{
  int result;
  Atom actual_type;
  int actual_format;
  unsigned long nitems, bytes_after;
  unsigned char *data = 0;

  result = XGetWindowProperty(mDisplay, aWindow, mMozLockAtom,
                              0, (65536 / sizeof(long)),
                              True, /* atomic delete after */
                              XA_STRING,
                              &actual_type, &actual_format,
                              &nitems, &bytes_after,
                              &data);
  if (result != Success) {
      MOZ_LOG(sRemoteLm, LogLevel::Debug,
             ("unable to read and delete " MOZILLA_LOCK_PROP
              " property\n"));
      return NS_ERROR_FAILURE;
  }
  else if (!data || !*data){
      MOZ_LOG(sRemoteLm, LogLevel::Debug,
             ("invalid data on " MOZILLA_LOCK_PROP
              " of window 0x%x.\n",
              (unsigned int) aWindow));
      return NS_ERROR_FAILURE;
  }
  else if (strcmp((char *)data, mLockData)) {
      MOZ_LOG(sRemoteLm, LogLevel::Debug,
             (MOZILLA_LOCK_PROP " was stolen!  Expected \"%s\", saw \"%s\"!\n",
              mLockData, data));
      return NS_ERROR_FAILURE;
  }

  if (data)
      XFree(data);
  return NS_OK;
}

/* like strcpy, but return the char after the final null */
static char*
estrcpy(const char* s, char* d)
{
  while (*s)
    *d++ = *s++;

  *d++ = '\0';
  return d;
}

nsresult
XRemoteClient::DoSendCommandLine(Window aWindow, int32_t argc, char **argv,
                                 const char* aDesktopStartupID,
                                 char **aResponse, bool *aDestroyed)
{
  *aDestroyed = false;

  char cwdbuf[MAX_PATH];
  if (!getcwd(cwdbuf, MAX_PATH))
    return NS_ERROR_UNEXPECTED;

  // the commandline property is constructed as an array of int32_t
  // followed by a series of null-terminated strings:
  //
  // [argc][offsetargv0][offsetargv1...]<workingdir>\0<argv[0]>\0argv[1]...\0
  // (offset is from the beginning of the buffer)

  static char desktopStartupPrefix[] = " DESKTOP_STARTUP_ID=";

  int32_t argvlen = strlen(cwdbuf);
  for (int i = 0; i < argc; ++i) {
    int32_t len = strlen(argv[i]);
    if (i == 0 && aDesktopStartupID) {
      len += sizeof(desktopStartupPrefix) - 1 + strlen(aDesktopStartupID);
    }
    argvlen += len;
  }

  int32_t* buffer = (int32_t*) malloc(argvlen + argc + 1 +
                                      sizeof(int32_t) * (argc + 1));
  if (!buffer)
    return NS_ERROR_OUT_OF_MEMORY;

  buffer[0] = TO_LITTLE_ENDIAN32(argc);

  char *bufend = (char*) (buffer + argc + 1);

  bufend = estrcpy(cwdbuf, bufend);

  for (int i = 0; i < argc; ++i) {
    buffer[i + 1] = TO_LITTLE_ENDIAN32(bufend - ((char*) buffer));
    bufend = estrcpy(argv[i], bufend);
    if (i == 0 && aDesktopStartupID) {
      bufend = estrcpy(desktopStartupPrefix, bufend - 1);
      bufend = estrcpy(aDesktopStartupID, bufend - 1);
    }
  }

#ifdef DEBUG_bsmedberg
  int32_t   debug_argc   = TO_LITTLE_ENDIAN32(*buffer);
  char *debug_workingdir = (char*) (buffer + argc + 1);

  printf("Sending command line:\n"
         "  working dir: %s\n"
         "  argc:\t%i",
         debug_workingdir,
         debug_argc);

  int32_t  *debug_offset = buffer + 1;
  for (int debug_i = 0; debug_i < debug_argc; ++debug_i)
    printf("  argv[%i]:\t%s\n", debug_i,
           ((char*) buffer) + TO_LITTLE_ENDIAN32(debug_offset[debug_i]));
#endif

  XChangeProperty (mDisplay, aWindow, mMozCommandLineAtom, XA_STRING, 8,
                   PropModeReplace, (unsigned char *) buffer,
                   bufend - ((char*) buffer));
  free(buffer);

  if (!WaitForResponse(aWindow, aResponse, aDestroyed, mMozCommandLineAtom))
    return NS_ERROR_FAILURE;
  
  return NS_OK;
}

bool
XRemoteClient::WaitForResponse(Window aWindow, char **aResponse,
                               bool *aDestroyed, Atom aCommandAtom)
{
  bool done = false;
  bool accepted = false;

  while (!done) {
    XEvent event;
    XNextEvent (mDisplay, &event);
    if (event.xany.type == DestroyNotify &&
        event.xdestroywindow.window == aWindow) {
      /* Print to warn user...*/
      MOZ_LOG(sRemoteLm, LogLevel::Debug,
             ("window 0x%x was destroyed.\n",
              (unsigned int) aWindow));
      *aResponse = strdup("Window was destroyed while reading response.");
      *aDestroyed = true;
      return false;
    }
    else if (event.xany.type == PropertyNotify &&
             event.xproperty.state == PropertyNewValue &&
             event.xproperty.window == aWindow &&
             event.xproperty.atom == mMozResponseAtom) {
      Atom actual_type;
      int actual_format;
      unsigned long nitems, bytes_after;
      unsigned char *data = 0;
      Bool result;
      result = XGetWindowProperty (mDisplay, aWindow, mMozResponseAtom,
                                   0, (65536 / sizeof (long)),
                                   True, /* atomic delete after */
                                   XA_STRING,
                                   &actual_type, &actual_format,
                                   &nitems, &bytes_after,
                                   &data);
      if (result != Success) {
        MOZ_LOG(sRemoteLm, LogLevel::Debug,
               ("failed reading " MOZILLA_RESPONSE_PROP
                " from window 0x%0x.\n",
                (unsigned int) aWindow));
        *aResponse = strdup("Internal error reading response from window.");
        done = true;
      }
      else if (!data || strlen((char *) data) < 5) {
        MOZ_LOG(sRemoteLm, LogLevel::Debug,
               ("invalid data on " MOZILLA_RESPONSE_PROP
                " property of window 0x%0x.\n",
                (unsigned int) aWindow));
        *aResponse = strdup("Server returned invalid data in response.");
        done = true;
      }
      else if (*data == '1') {  /* positive preliminary reply */
        MOZ_LOG(sRemoteLm, LogLevel::Debug,  ("%s\n", data + 4));
        /* keep going */
        done = false;
      }

      else if (!strncmp ((char *)data, "200", 3)) { /* positive completion */
        *aResponse = strdup((char *)data);
        accepted = true;
        done = true;
      }

      else if (*data == '2') {  /* positive completion */
        MOZ_LOG(sRemoteLm, LogLevel::Debug, ("%s\n", data + 4));
        *aResponse = strdup((char *)data);
        accepted = true;
        done = true;
      }

      else if (*data == '3') {  /* positive intermediate reply */
        MOZ_LOG(sRemoteLm, LogLevel::Debug,
               ("internal error: "
                "server wants more information?  (%s)\n",
                data));
        *aResponse = strdup((char *)data);
        done = true;
      }

      else if (*data == '4' ||  /* transient negative completion */
               *data == '5') {  /* permanent negative completion */
        MOZ_LOG(sRemoteLm, LogLevel::Debug, ("%s\n", data + 4));
        *aResponse = strdup((char *)data);
        done = true;
      }

      else {
        MOZ_LOG(sRemoteLm, LogLevel::Debug,
               ("unrecognised " MOZILLA_RESPONSE_PROP
                " from window 0x%x: %s\n",
                (unsigned int) aWindow, data));
        *aResponse = strdup((char *)data);
        done = true;
      }

      if (data)
        XFree(data);
    }

    else if (event.xany.type == PropertyNotify &&
             event.xproperty.window == aWindow &&
             event.xproperty.state == PropertyDelete &&
             event.xproperty.atom == aCommandAtom) {
      MOZ_LOG(sRemoteLm, LogLevel::Debug,
             ("(server 0x%x has accepted "
              MOZILLA_COMMANDLINE_PROP ".)\n",
              (unsigned int) aWindow));
    }
    
  }

  return accepted;
}