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
|
/* Copyright (c) 2008, 2009 Nicira Networks, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "extras/ezio/vt.h"
#include <errno.h>
#include <fcntl.h>
#include <linux/kd.h>
#include <linux/vt.h>
#include <stdint.h>
#include <string.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include "util.h"
#define THIS_MODULE VLM_vt
#include "vlog.h"
static bool get_console_fd(int *fd);
int
vt_open(int open_flags)
{
int console_fd, vt_fd;
char name[16];
int vt;
if (!get_console_fd(&console_fd)) {
return -EACCES;
}
/* Deallocate all unused virtual terminals, so that we don't proliferate an
* excess of empty ones over multiple runs. */
if (ioctl(console_fd, VT_DISALLOCATE, 0) < 0) {
VLOG_WARN("failed to deallocate empty virtual terminals: %s",
strerror(errno));
}
/* Find a unused virtual terminal. */
if (ioctl(console_fd, VT_OPENQRY, &vt) < 0) {
int error = errno;
VLOG_ERR("failed to find a free virtual terminal: %s",
strerror(error));
close(console_fd);
return -error;
}
/* Open virtual terminal. */
sprintf(name, "/dev/tty%d", vt);
vt_fd = open(name, open_flags);
if (vt_fd < 0) {
int error = errno;
VLOG_ERR("failed to open %s: %s", name, strerror(error));
close(console_fd);
return -error;
}
/* Activate virtual terminal. */
if (ioctl(console_fd, VT_ACTIVATE, vt) < 0
|| ioctl(console_fd, VT_WAITACTIVE, vt) < 0) {
int error = errno;
VLOG_ERR("could not activate virtual terminal %d: %s",
vt, strerror(error));
close(console_fd);
close(vt_fd);
return -error;
}
/* Success. */
VLOG_DBG("allocated virtual terminal %d (%s)", vt, name);
close(console_fd);
return vt_fd;
}
static bool
is_console(int fd)
{
uint8_t type = 0;
return !ioctl(fd, KDGKBTYPE, &type) && (type == KB_101 || type == KB_84);
}
static bool
open_console(const char *name, int *fdp)
{
*fdp = open(name, O_RDWR | O_NOCTTY);
if (*fdp >= 0) {
if (is_console(*fdp)) {
return true;
}
close(*fdp);
}
return false;
}
static bool
get_console_fd(int *fdp)
{
int fd;
if (open_console("/dev/tty", fdp)
|| open_console("/dev/tty0", fdp)
|| open_console("/dev/console", fdp)) {
return true;
}
for (fd = 0; fd < 3; fd++) {
if (is_console(fd)) {
*fdp = dup(fd);
if (*fdp >= 0) {
return true;
}
}
}
VLOG_ERR("unable to obtain a file descriptor for the console");
return false;
}
|
