source: MondoRescue/branches/stable/mindi-busybox/libbb/get_console.c @ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 14 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)

File size: 1.5 KB
Line 
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 tarball for details.
9 */
10
11#include <stdio.h>
12#include <errno.h>
13#include <fcntl.h>
14#include <unistd.h>
15#include <sys/ioctl.h>
16#include "libbb.h"
17
18
19
20/* From <linux/kd.h> */
21enum { KDGKBTYPE = 0x4B33 };  /* get keyboard type */
22
23
24static int open_a_console(const char *fnam)
25{
26    int fd;
27
28    /* try read-write */
29    fd = open(fnam, O_RDWR);
30
31    /* if failed, try read-only */
32    if (fd < 0 && errno == EACCES)
33        fd = open(fnam, O_RDONLY);
34
35    /* if failed, try write-only */
36    if (fd < 0 && errno == EACCES)
37        fd = open(fnam, O_WRONLY);
38
39    return fd;
40}
41
42/*
43 * Get an fd for use with kbd/console ioctls.
44 * We try several things because opening /dev/console will fail
45 * if someone else used X (which does a chown on /dev/console).
46 */
47
48int get_console_fd(void)
49{
50    int fd;
51
52    static const char * const choise_console_names[] = {
53        CONSOLE_DEV, CURRENT_VC, CURRENT_TTY
54    };
55
56    for (fd = 2; fd >= 0; fd--) {
57        int fd4name;
58        int choise_fd;
59        char arg;
60
61        fd4name = open_a_console(choise_console_names[fd]);
62    chk_std:
63        choise_fd = fd4name >= 0 ? fd4name : fd;
64
65        arg = 0;
66        if (ioctl(choise_fd, KDGKBTYPE, &arg) == 0)
67            return choise_fd;
68        if(fd4name >= 0) {
69            close(fd4name);
70            fd4name = -1;
71            goto chk_std;
72        }
73    }
74
75    bb_error_msg("Couldn't get a file descriptor referring to the console");
76    return fd;                      /* total failure */
77}
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