1 /* vi: set sw=4 ts=4: */
2 /*
3 * Utility routines.
4 *
5 * Copyright (C) many different people. If you wrote this, please
6 * acknowledge your work.
7 *
8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
9 */
10
11 #include "libbb.h"
12
13 /* From <linux/kd.h> */
14 enum { KDGKBTYPE = 0x4B33 }; /* get keyboard type */
15
open_a_console(const char * fnam)16 static int open_a_console(const char *fnam)
17 {
18 int fd;
19
20 /* try read-write */
21 fd = open(fnam, O_RDWR);
22
23 /* if failed, try read-only */
24 if (fd < 0 && errno == EACCES)
25 fd = open(fnam, O_RDONLY);
26
27 /* if failed, try write-only */
28 if (fd < 0 && errno == EACCES)
29 fd = open(fnam, O_WRONLY);
30
31 return fd;
32 }
33
34 /*
35 * Get an fd for use with kbd/console ioctls.
36 * We try several things because opening /dev/console will fail
37 * if someone else used X (which does a chown on /dev/console).
38 */
get_console_fd_or_die(void)39 int FAST_FUNC get_console_fd_or_die(void)
40 {
41 static const char *const console_names[] = {
42 DEV_CONSOLE, CURRENT_VC, CURRENT_TTY
43 };
44
45 int fd;
46
47 for (fd = 2; fd >= 0; fd--) {
48 int fd4name;
49 int choice_fd;
50 char arg;
51
52 fd4name = open_a_console(console_names[fd]);
53 chk_std:
54 choice_fd = (fd4name >= 0 ? fd4name : fd);
55
56 arg = 0;
57 if (ioctl(choice_fd, KDGKBTYPE, &arg) == 0)
58 return choice_fd;
59 if (fd4name >= 0) {
60 close(fd4name);
61 fd4name = -1;
62 goto chk_std;
63 }
64 }
65
66 bb_error_msg_and_die("can't open console");
67 /*return fd; - total failure */
68 }
69
70 /* From <linux/vt.h> */
71 enum {
72 VT_ACTIVATE = 0x5606, /* make vt active */
73 VT_WAITACTIVE = 0x5607 /* wait for vt active */
74 };
75
console_make_active(int fd,const int vt_num)76 void FAST_FUNC console_make_active(int fd, const int vt_num)
77 {
78 xioctl(fd, VT_ACTIVATE, (void *)(ptrdiff_t)vt_num);
79 xioctl(fd, VT_WAITACTIVE, (void *)(ptrdiff_t)vt_num);
80 }
81