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
|
/*
Set and restore VC screen for vlock, the VT locking program for linux.
Copyright (C) 1997-1998 Juan Cespedes <cespedes@debian.org>
Copyright (C) 2002, 2004, 2006 Dmitry V. Levin <ldv@altlinux.org>
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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include "vlock.h"
static unsigned char lines, columns;
static void *screen_buf = 0;
static int vcs = -1;
void init_screen(void)
{
int failed = 1;
const char clear_str[] = "\33[3J\33[H\33[J";
vcs = -1;
do {
struct stat st;
unsigned i, size;
char path[16];
if (fstat(STDIN_FILENO, &st) == -1)
break;
if (!S_ISCHR(st.st_mode))
break;
if ((st.st_rdev >> 8) != 4)
break;
i = st.st_rdev & 0xff;
sprintf(path, "/dev/vcsa%u", i);
vcs = open(path, O_RDWR);
if (vcs < 0)
break;
if (read(vcs, &columns, 1) != 1)
break;
if (read(vcs, &lines, 1) != 1)
break;
size = 2 * lines * columns + 2;
screen_buf = malloc(size);
if (!screen_buf)
break;
if (read(vcs, screen_buf, size) != (int)size) {
free(screen_buf);
screen_buf = NULL;
break;
}
failed = 0;
} while (0);
if (failed && vcs >= 0) {
close(vcs);
vcs = -1;
}
/* There's no need to use ncurses */
if (write(STDOUT_FILENO, clear_str, sizeof(clear_str) - 1) !=
sizeof(clear_str) - 1)
return;
}
void restore_screen(void)
{
if (screen_buf) {
do {
if (lseek(vcs, 0, SEEK_SET))
break;
if (write(vcs, &columns, 1) != 1)
break;
if (write(vcs, &lines, 1) != 1)
break;
if (write(vcs, screen_buf, 2 * lines * columns + 2) !=
2 * lines * columns + 2)
break;
} while (0);
close(vcs);
}
}
|
