diff options
author | Eric Andersen <andersen@codepoet.org> | 2001-03-17 01:47:14 +0300 |
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committer | Eric Andersen <andersen@codepoet.org> | 2001-03-17 01:47:14 +0300 |
commit | aad1a88c76f208d188fd061e3723bd637437e8d5 (patch) | |
tree | 75ac2b994f7f04af776e93eeedba82b873ff557e /libbb/get_console.c | |
parent | dfba13d199bb58d802df99c1ef20fdc0d628e86d (diff) |
Convert utility.c into libbb.a. It is now a whole pile of .c
files. Clean up the resulting damage and fix up the makefile.
-Erik
Diffstat (limited to 'libbb/get_console.c')
-rw-r--r-- | libbb/get_console.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/libbb/get_console.c b/libbb/get_console.c new file mode 100644 index 000000000..4be9adc84 --- /dev/null +++ b/libbb/get_console.c @@ -0,0 +1,129 @@ +/* vi: set sw=4 ts=4: */ +/* + * Utility routines. + * + * Copyright (C) tons of folks. Tracking down who wrote what + * isn't something I'm going to worry about... If you wrote something + * here, please feel free to 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 + * + * Based in part on code from sash, Copyright (c) 1999 by David I. Bell + * Permission has been granted to redistribute this code under the GPL. + * + */ + +#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 const int KB_84 = 0x01; +static const int KB_101 = 0x02; /* this is what we always answer */ + +int is_a_console(int fd) +{ + char arg; + + arg = 0; + return (ioctl(fd, KDGKBTYPE, &arg) == 0 + && ((arg == KB_101) || (arg == KB_84))); +} + +static int open_a_console(char *fnam) +{ + int fd; + + /* try read-only */ + 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); + + /* if failed, fail */ + if (fd < 0) + return -1; + + /* if not a console, fail */ + if (!is_a_console(fd)) { + close(fd); + return -1; + } + + /* success */ + 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). + * + * if tty_name is non-NULL, try this one instead. + */ + +int get_console_fd(char *tty_name) +{ + int fd; + + if (tty_name) { + if (-1 == (fd = open_a_console(tty_name))) + return -1; + else + return fd; + } + + fd = open_a_console("/dev/tty"); + if (fd >= 0) + return fd; + + fd = open_a_console("/dev/tty0"); + if (fd >= 0) + return fd; + + fd = open_a_console("/dev/console"); + if (fd >= 0) + return fd; + + for (fd = 0; fd < 3; fd++) + if (is_a_console(fd)) + return fd; + + error_msg("Couldnt get a file descriptor referring to the console"); + return -1; /* total failure */ +} + + +/* END CODE */ +/* +Local Variables: +c-file-style: "linux" +c-basic-offset: 4 +tab-width: 4 +End: +*/ |