1 files changed, 202 insertions, 0 deletions
diff --git a/common/terminal.c b/common/terminal.c
new file mode 100644
index 0000000..c9ee758
--- /dev/null
+++ b/common/terminal.c
@@ -0,0 +1,202 @@
+#include "string.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/kd.h>
+#include <linux/vt.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include "log.h"
+#include "terminal.h"
+
+#define TTYPATHLEN 64
+
+int terminal_current_vt(void) {
+	struct vt_stat st;
+	int fd = open("/dev/tty0", O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not open tty0: %s", strerror(errno));
+		return -1;
+	}
+	int res = ioctl(fd, VT_GETSTATE, &st);
+	close(fd);
+	if (res == -1) {
+		log_errorf("could not retrieve VT state: %s", strerror(errno));
+		return -1;
+	}
+	return st.v_active;
+}
+
+int terminal_setup(int vt) {
+	log_debugf("setting up vt %d", vt);
+	if (vt == -1) {
+		vt = 0;
+	}
+	char path[TTYPATHLEN];
+	if (snprintf(path, TTYPATHLEN, "/dev/tty%d", vt) == -1) {
+		log_errorf("could not generate tty path: %s", strerror(errno));
+		return -1;
+	}
+	int fd = open(path, O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not open target tty: %s", strerror(errno));
+		return -1;
+	}
+
+	static struct vt_mode mode = {
+		.mode = VT_PROCESS,
+		.waitv = 0,
+		.relsig = SIGUSR1,
+		.acqsig = SIGUSR2,
+		.frsig = 0,
+	};
+
+	int res = ioctl(fd, VT_SETMODE, &mode);
+	close(fd);
+	if (res == -1) {
+		log_errorf("could not set VT mode: %s", strerror(errno));
+	}
+
+	return res;
+}
+
+int terminal_teardown(int vt) {
+	log_debugf("tearing down vt %d", vt);
+	if (vt == -1) {
+		vt = 0;
+	}
+	char path[TTYPATHLEN];
+	if (snprintf(path, TTYPATHLEN, "/dev/tty%d", vt) == -1) {
+		log_errorf("could not generate tty path: %s", strerror(errno));
+		return -1;
+	}
+	int fd = open(path, O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not open target tty: %s", strerror(errno));
+		return -1;
+	}
+	if (ioctl(fd, KDSETMODE, KD_TEXT) == -1) {
+		log_errorf("could not set KD graphics mode: %s", strerror(errno));
+		close(fd);
+		return -1;
+	}
+	if (ioctl(fd, KDSKBMODE, K_UNICODE) == -1) {
+		log_errorf("could not set KD keyboard mode: %s", strerror(errno));
+		close(fd);
+		return -1;
+	}
+
+	static struct vt_mode mode = {
+		.mode = VT_PROCESS,
+		.waitv = 0,
+		.relsig = SIGUSR1,
+		.acqsig = SIGUSR2,
+		.frsig = 0,
+	};
+	if (ioctl(fd, VT_SETMODE, &mode) == -1) {
+		log_errorf("could not set VT mode: %s", strerror(errno));
+		close(fd);
+		return -1;
+	}
+
+	close(fd);
+	return 0;
+}
+
+int terminal_switch_vt(int vt) {
+	log_debugf("switching to vt %d", vt);
+	int fd = open("/dev/tty0", O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not open tty0: %s", strerror(errno));
+		return -1;
+	}
+
+	static struct vt_mode mode = {
+		.mode = VT_PROCESS,
+		.waitv = 0,
+		.relsig = SIGUSR1,
+		.acqsig = SIGUSR2,
+		.frsig = 0,
+	};
+
+	if (ioctl(fd, VT_SETMODE, &mode) == -1) {
+		log_errorf("could not set VT mode: %s", strerror(errno));
+		close(fd);
+		return -1;
+	}
+
+	if (ioctl(fd, VT_ACTIVATE, vt) == -1) {
+		log_errorf("could not activate VT: %s", strerror(errno));
+		close(fd);
+		return -1;
+	}
+
+	close(fd);
+	return 0;
+}
+
+int terminal_ack_switch(void) {
+	log_debug("acking vt switch");
+	int fd = open("/dev/tty0", O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not open tty0: %s", strerror(errno));
+		return -1;
+	}
+
+	int res = ioctl(fd, VT_RELDISP, VT_ACKACQ);
+	close(fd);
+	if (res == -1) {
+		log_errorf("could not ack VT switch: %s", strerror(errno));
+	}
+
+	return res;
+}
+
+int terminal_set_keyboard(int vt, bool enable) {
+	log_debugf("setting KD keyboard state to %d on vt %d", enable, vt);
+	if (vt == -1) {
+		vt = 0;
+	}
+	char path[TTYPATHLEN];
+	if (snprintf(path, TTYPATHLEN, "/dev/tty%d", vt) == -1) {
+		log_errorf("could not generate tty path: %s", strerror(errno));
+		return -1;
+	}
+	int fd = open(path, O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not generate tty path: %s", strerror(errno));
+		return -1;
+	}
+	int res = ioctl(fd, KDSKBMODE, enable ? K_UNICODE : K_OFF);
+	close(fd);
+	if (res == -1) {
+		log_errorf("could not set KD keyboard mode: %s", strerror(errno));
+	}
+	return res;
+}
+
+int terminal_set_graphics(int vt, bool enable) {
+	log_debugf("setting KD graphics state to %d on vt %d", enable, vt);
+	if (vt == -1) {
+		vt = 0;
+	}
+	char path[TTYPATHLEN];
+	if (snprintf(path, TTYPATHLEN, "/dev/tty%d", vt) == -1) {
+		log_errorf("could not generate tty path: %s", strerror(errno));
+		return -1;
+	}
+	int fd = open(path, O_RDWR | O_NOCTTY);
+	if (fd == -1) {
+		log_errorf("could not generate tty path: %s", strerror(errno));
+		return -1;
+	}
+	int res = ioctl(fd, KDSETMODE, enable ? KD_GRAPHICS : KD_TEXT);
+	close(fd);
+	if (res == -1) {
+		log_errorf("could not set KD graphics mode: %s", strerror(errno));
+	}
+	return res;
+}