1 files changed, 80 insertions, 0 deletions
diff --git a/libbb/get_console.c b/libbb/get_console.c
new file mode 100644
index 0000000..74022b5
--- /dev/null
+++ b/libbb/get_console.c
@@ -0,0 +1,80 @@
+/* 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 "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");
+	/*return fd; - total failure */
+}
+
+/* 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);
+}