summaryrefslogtreecommitdiff
path: root/src/errors.c
blob: d558de03fd869a3e67f7b841c27798e9ddc131e3 (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
/* Metacity X error handling */

/* 
 * Copyright (C) 2001 Havoc Pennington, error trapping inspired by GDK
 * code copyrighted by the GTK team.
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 */

#include <config.h>
#include "errors.h"
#include <errno.h>
#include <stdlib.h>
#include <gdk/gdk.h>

static int sync_count = 0;

static int x_error_handler    (Display     *display,
                               XErrorEvent *error);
static int x_io_error_handler (Display     *display);

void
meta_errors_init (void)
{
  XSetErrorHandler (x_error_handler);
  XSetIOErrorHandler (x_io_error_handler);
}

static void
meta_error_trap_push_internal (MetaDisplay *display,
                               gboolean     need_sync)
{
  /* GDK resets the error handler on each push */
  int (* old_error_handler) (Display     *,
                             XErrorEvent *);

  if (need_sync)
    {
      XSync (display->xdisplay, False);
      ++sync_count;
    }
  
  gdk_error_trap_push ();

  /* old_error_handler will just be equal to x_error_handler
   * for nested traps
   */
  old_error_handler = XSetErrorHandler (x_error_handler);
  
  /* Replace GDK handler, but save it so we can chain up */
  if (display->error_trap_handler == NULL)
    {
      g_assert (display->error_traps == 0);
      display->error_trap_handler = old_error_handler;
      g_assert (display->error_trap_handler != x_error_handler);
    }

  display->error_traps += 1;

  meta_topic (META_DEBUG_ERRORS, "%d traps remain\n", display->error_traps);
}

static int
meta_error_trap_pop_internal  (MetaDisplay *display,
                               gboolean     need_sync)
{
  int result;

  g_assert (display->error_traps > 0);

  if (need_sync)
    {
      XSync (display->xdisplay, False);
      ++sync_count;
    }

  result = gdk_error_trap_pop ();

  display->error_traps -= 1;
  
  if (display->error_traps == 0)
    {
      /* check that GDK put our handler back; this
       * assumes that there are no pending GDK traps from GDK itself
       */
      
      int (* restored_error_handler) (Display     *,
                                      XErrorEvent *);

      restored_error_handler = XSetErrorHandler (x_error_handler);
      g_assert (restored_error_handler == x_error_handler);

      /* remove this */
      display->error_trap_handler = NULL;
    }

  meta_topic (META_DEBUG_ERRORS, "%d traps\n", display->error_traps);
  
  return result;
}

void
meta_error_trap_push (MetaDisplay *display)
{
  meta_error_trap_push_internal (display, FALSE);
}

void
meta_error_trap_pop (MetaDisplay *display,
                     gboolean     last_request_was_roundtrip)
{
  gboolean need_sync;

  /* we only have to sync when popping the outermost trap */
  need_sync = (display->error_traps == 1 && !last_request_was_roundtrip);

  if (need_sync)
    meta_topic (META_DEBUG_SYNC, "%d: Syncing on error_trap_pop, traps = %d, roundtrip = %d\n",
                sync_count, display->error_traps, last_request_was_roundtrip);

  display->error_trap_synced_at_last_pop = need_sync || last_request_was_roundtrip;
  
  meta_error_trap_pop_internal (display, need_sync);
}

void
meta_error_trap_push_with_return (MetaDisplay *display)
{
  gboolean need_sync;

  /* We don't sync on push_with_return if there are no traps
   * currently, because we assume that any errors were either covered
   * by a previous pop, or were fatal.
   *
   * More generally, we don't sync if we were synchronized last time
   * we popped. This is known to be the case if there are no traps,
   * but we also keep a flag so we know whether it's the case otherwise.
   */

  if (!display->error_trap_synced_at_last_pop)
    need_sync = TRUE;
  else
    need_sync = FALSE;

  if (need_sync)
    meta_topic (META_DEBUG_SYNC, "%d: Syncing on error_trap_push_with_return, traps = %d\n",
                sync_count, display->error_traps);
  
  meta_error_trap_push_internal (display, FALSE);
}

int
meta_error_trap_pop_with_return  (MetaDisplay *display,
                                  gboolean     last_request_was_roundtrip)
{
  if (!last_request_was_roundtrip)
    meta_topic (META_DEBUG_SYNC, "%d: Syncing on error_trap_pop_with_return, traps = %d, roundtrip = %d\n",
                sync_count, display->error_traps, last_request_was_roundtrip);

  display->error_trap_synced_at_last_pop = TRUE;
  
  return meta_error_trap_pop_internal (display,
                                       !last_request_was_roundtrip);
}

static int
x_error_handler (Display     *xdisplay,
                 XErrorEvent *error)
{
  int retval;
  gchar buf[64];
  MetaDisplay *display;
  
  XGetErrorText (xdisplay, error->error_code, buf, 63);  

  display = meta_display_for_x_display (xdisplay);
  
  if (display->error_traps > 0)
    {
      /* we're in an error trap, chain to the trap handler
       * saved from GDK
       */
      meta_verbose ("X error: %s serial %ld error_code %d request_code %d minor_code %d)\n",
                    buf,
                    error->serial, 
                    error->error_code, 
                    error->request_code,
                    error->minor_code);

      g_assert (display->error_trap_handler != NULL);
      g_assert (display->error_trap_handler != x_error_handler);
      
      retval = (* display->error_trap_handler) (xdisplay, error);
    }
  else
    {
      meta_bug ("Unexpected X error: %s serial %ld error_code %d request_code %d minor_code %d)\n",
                buf,
                error->serial, 
                error->error_code, 
                error->request_code,
                error->minor_code);

      retval = 1; /* compiler warning */
    }

  return retval;
}

static int
x_io_error_handler (Display *xdisplay)
{
  MetaDisplay *display;

  display = meta_display_for_x_display (xdisplay);

  if (display == NULL)
    meta_bug ("IO error received for unknown display?\n");
  
  if (errno == EPIPE)
    {
      meta_warning (_("Lost connection to the display '%s';\n"
                      "most likely the X server was shut down or you killed/destroyed\n"
                      "the window manager.\n"),
                    display->name);
    }
  else
    {
      meta_warning (_("Fatal IO error %d (%s) on display '%s'.\n"),
                    errno, g_strerror (errno),
                    display->name);
    }

  /* Xlib would force an exit anyhow */
  exit (1);
  
  return 0;
}