diff options
Diffstat (limited to 'busybox/libbb/get_console.c')
-rw-r--r-- | busybox/libbb/get_console.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/busybox/libbb/get_console.c b/busybox/libbb/get_console.c new file mode 100644 index 0000000..bfb7468 --- /dev/null +++ b/busybox/libbb/get_console.c @@ -0,0 +1,99 @@ +/* vi: set sw=4 ts=4: */ +/* + * Utility routines. + * + * Copyright (C) many different people. If you wrote this, please + * acknowledge your work. + * + * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <stdio.h> +#include <errno.h> +#include <fcntl.h> +#include <unistd.h> +#include <sys/ioctl.h> +#include "libbb.h" + + + +/* From <linux/kd.h> */ +static const int 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 get_console_fd(void) +{ + int fd; + + static const char * const choise_console_names[] = { + CONSOLE_DEV, CURRENT_VC, CURRENT_TTY + }; + + for (fd = 2; fd >= 0; fd--) { + int fd4name; + int choise_fd; + char arg; + + fd4name = open_a_console(choise_console_names[fd]); + chk_std: + choise_fd = fd4name >= 0 ? fd4name : fd; + + arg = 0; + if (ioctl(choise_fd, KDGKBTYPE, &arg) == 0) + return choise_fd; + if(fd4name >= 0) { + close(fd4name); + fd4name = -1; + goto chk_std; + } + } + + bb_error_msg("Couldn't get a file descriptor referring to the console"); + return fd; /* total failure */ +} + + +/* END CODE */ +/* +Local Variables: +c-file-style: "linux" +c-basic-offset: 4 +tab-width: 4 +End: +*/ |