Add initial version of getty

Makefile

@@ -26,6 +26,7 @@ SRC = \
 	eject.c             \
 	fallocate.c         \
 	free.c              \
+	getty.c             \
 	halt.c              \
 	insmod.c            \
 	lsmod.c             \

TODO

@@ -13,7 +13,6 @@ Tools
  * mkswap [-L]
  * passwd
  * login
- * getty
 
 Other
 =====

getty.c

@@ -0,0 +1,80 @@
+/* See LICENSE file for copyright and license details. */
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: %s [tty] [term]\n", argv0);
+}
+
+static char *tty = "/dev/tty1";
+static char *defaultterm = "TERM=linux";
+
+int
+main(int argc, char *argv[])
+{
+	int fd;
+	struct sigaction sa;
+	char term[128];
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc > 2)
+		usage();
+
+	strlcpy(term, defaultterm, sizeof(term));
+	if (argc > 0) {
+		tty = argv[0];
+		if (argc > 1) {
+			strlcpy(term, "TERM=", sizeof(term));
+			strlcat(term, argv[1], sizeof(term));
+		}
+	}
+
+	sa.sa_handler = SIG_IGN;
+	sa.sa_flags = 0;
+	sigemptyset(&sa.sa_mask);
+	sigaction(SIGHUP, &sa, NULL);
+
+	putenv(term);
+
+	setsid();
+
+	fd = open(tty, O_RDWR);
+	if (fd < 0)
+		eprintf("open %s:", tty);
+	if (isatty(fd) == 0)
+		eprintf("%s is not a tty\n", tty);
+	if (ioctl(fd, TIOCSCTTY, (void *)1) == 0) {
+		if (vhangup() < 0)
+			eprintf("vhangup:");
+	} else {
+		fprintf(stderr, "could not set controlling tty\n");
+	}
+	close(fd);
+	fd = open(tty, O_RDWR);
+	if (fd < 0)
+		eprintf("open %s:", tty);
+	dup2(fd, STDIN_FILENO);
+	dup2(fd, STDOUT_FILENO);
+	dup2(fd, STDERR_FILENO);
+
+	sa.sa_handler = SIG_DFL;
+	sa.sa_flags = 0;
+	sigemptyset(&sa.sa_mask);
+	sigaction(SIGHUP, &sa, NULL);
+
+	putchar('\n');
+	return execvp("/bin/login", (char *[]){ "login", NULL });
+}