| /* vi: set sw=4 ts=4: */ |
| /* |
| * Utility routines. |
| * |
| * Copyright (C) many different people. If you wrote this, please |
| * acknowledge your work. |
| * |
| * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| */ |
| #include "libbb.h" |
| |
| /* From <linux/kd.h> */ |
| enum { KDGKBTYPE = 0x4B33 }; /* get keyboard type */ |
| |
| static int open_a_console(const char *fnam) |
| { |
| int fd; |
| |
| /* try read-write */ |
| fd = open(fnam, O_RDWR); |
| |
| /* if failed, try read-only */ |
| if (fd < 0 && errno == EACCES) |
| fd = open(fnam, O_RDONLY); |
| |
| /* if failed, try write-only */ |
| if (fd < 0 && errno == EACCES) |
| fd = open(fnam, O_WRONLY); |
| |
| return fd; |
| } |
| |
| /* |
| * Get an fd for use with kbd/console ioctls. |
| * We try several things because opening /dev/console will fail |
| * if someone else used X (which does a chown on /dev/console). |
| */ |
| int FAST_FUNC get_console_fd_or_die(void) |
| { |
| static const char *const console_names[] = { |
| DEV_CONSOLE, CURRENT_VC, CURRENT_TTY |
| }; |
| |
| int fd; |
| |
| for (fd = 2; fd >= 0; fd--) { |
| int fd4name; |
| int choice_fd; |
| char arg; |
| |
| fd4name = open_a_console(console_names[fd]); |
| chk_std: |
| choice_fd = (fd4name >= 0 ? fd4name : fd); |
| |
| arg = 0; |
| if (ioctl(choice_fd, KDGKBTYPE, &arg) == 0) |
| return choice_fd; |
| if (fd4name >= 0) { |
| close(fd4name); |
| fd4name = -1; |
| goto chk_std; |
| } |
| } |
| |
| bb_error_msg_and_die("can't open console"); |
| } |
| |
| /* From <linux/vt.h> */ |
| enum { |
| VT_ACTIVATE = 0x5606, /* make vt active */ |
| VT_WAITACTIVE = 0x5607 /* wait for vt active */ |
| }; |
| |
| void FAST_FUNC console_make_active(int fd, const int vt_num) |
| { |
| xioctl(fd, VT_ACTIVATE, (void *)(ptrdiff_t)vt_num); |
| xioctl(fd, VT_WAITACTIVE, (void *)(ptrdiff_t)vt_num); |
| } |