add login_tty function

include/utmp.h

@@ -35,6 +35,8 @@ void         setutent(void);
 
 void updwtmp(const char *, const struct utmp *);
 
+int login_tty(int);
+
 #define _PATH_UTMP "/dev/null/utmp"
 #define _PATH_WTMP "/dev/null/wtmp"
 

src/misc/login_tty.c

@@ -0,0 +1,14 @@
+#include <utmp.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+int login_tty(int fd)
+{
+	setsid();
+	if (ioctl(fd, TIOCSCTTY, (char *)0)) return -1;
+	dup2(fd, 0);
+	dup2(fd, 1);
+	dup2(fd, 2);
+	if (fd>2) close(fd);
+	return 0;
+}