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
|
/*
* Copyright (C) 2010-2011 Robert Ancell.
* Author: Robert Ancell <robert.ancell@canonical.com>
*
* 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 3 of the License, or (at your option) any later
* version. See http://www.gnu.org/copyleft/gpl.html the full text of the
* license.
*/
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <glib/gstdio.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#ifdef __linux__
#include <linux/vt.h>
#endif
#include "vt.h"
#include "configuration.h"
static GList *used_vts = NULL;
static gint
open_tty (void)
{
int fd;
fd = g_open ("/dev/tty0", O_RDONLY | O_NOCTTY, 0);
if (fd < 0)
g_warning ("Error opening /dev/tty0: %s", strerror (errno));
return fd;
}
gboolean
vt_can_multi_seat (void)
{
/* Quick check to see if we can multi seat. This is intentionally the
same check logind does, just without actually reading from the files.
Existence will prove whether we have CONFIG_VT built into the kernel. */
return access ("/dev/tty0", F_OK) == 0 &&
access ("/sys/class/tty/tty0/active", F_OK) == 0;
}
gint
vt_get_active (void)
{
#ifdef __linux__
gint tty_fd;
gint active = -1;
/* Pretend always active */
if (getuid () != 0)
return 1;
tty_fd = open_tty ();
if (tty_fd >= 0)
{
struct vt_stat vt_state = { 0 };
if (ioctl (tty_fd, VT_GETSTATE, &vt_state) < 0)
g_warning ("Error using VT_GETSTATE on /dev/tty0: %s", strerror (errno));
else
active = vt_state.v_active;
close (tty_fd);
}
return active;
#else
return -1;
#endif
}
void
vt_set_active (gint number)
{
#ifdef __linux__
gint tty_fd;
g_debug ("Activating VT %d", number);
/* Pretend always active */
if (getuid () != 0)
return;
tty_fd = open_tty ();
if (tty_fd >= 0)
{
int n = number;
if (ioctl (tty_fd, VT_ACTIVATE, n) < 0)
{
g_warning ("Error using VT_ACTIVATE %d on /dev/tty0: %s", n, strerror (errno));
close (tty_fd);
return;
}
/* Wait for the VT to become active to avoid a suspected
* race condition somewhere between LightDM, X, ConsoleKit and the kernel.
* See https://bugs.launchpad.net/bugs/851612 */
if (ioctl (tty_fd, VT_WAITACTIVE, n) < 0)
g_warning ("Error using VT_WAITACTIVE %d on /dev/tty0: %s", n, strerror (errno));
close (tty_fd);
}
#endif
}
static gboolean
vt_is_used (gint number)
{
GList *link;
for (link = used_vts; link; link = link->next)
{
int n = GPOINTER_TO_INT (link->data);
if (n == number)
return TRUE;
}
return FALSE;
}
gint
vt_get_min (void)
{
gint number;
number = config_get_integer (config_get_instance (), "LightDM", "minimum-vt");
if (number < 1)
number = 1;
return number;
}
gint
vt_get_unused (void)
{
gint number;
if (getuid () != 0)
return -1;
number = vt_get_min ();
while (vt_is_used (number))
number++;
return number;
}
void
vt_ref (gint number)
{
g_debug ("Using VT %d", number);
used_vts = g_list_append (used_vts, GINT_TO_POINTER (number));
}
void
vt_unref (gint number)
{
g_debug ("Releasing VT %d", number);
used_vts = g_list_remove (used_vts, GINT_TO_POINTER (number));
}
|