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path: root/i/pc104/initrd/conf/busybox/libbb/get_console.c
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Diffstat (limited to 'i/pc104/initrd/conf/busybox/libbb/get_console.c')
-rw-r--r--i/pc104/initrd/conf/busybox/libbb/get_console.c72
1 files changed, 72 insertions, 0 deletions
diff --git a/i/pc104/initrd/conf/busybox/libbb/get_console.c b/i/pc104/initrd/conf/busybox/libbb/get_console.c
new file mode 100644
index 0000000..42ee137
--- /dev/null
+++ b/i/pc104/initrd/conf/busybox/libbb/get_console.c
@@ -0,0 +1,72 @@
+/* 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 tarball for details.
+ */
+
+#include <sys/ioctl.h>
+#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 get_console_fd(void)
+{
+ static const char *const console_names[] = {
+ DEV_CONSOLE, CURRENT_VC, CURRENT_TTY
+ };
+
+ int fd;
+
+ for (fd = 2; fd >= 0; fd--) {
+ int fd4name;
+ int choise_fd;
+ char arg;
+
+ fd4name = open_a_console(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("cannot get file descriptor referring to console");
+ return fd; /* total failure */
+}