Add tcsetsid(3).

The entire world seems to use the non-standard TIOCSCTTY ioctl to make a
TTY a controlling terminal of a session. Even though tcsetsid(3) is also
non-standard, I think it's a lot better to use in our own source code,
mainly because it's similar to tcsetpgrp(), tcgetpgrp() and tcgetsid().

I stole the idea from QNX. They do it the other way around; their
TIOCSCTTY is just a wrapper around tcsetsid(). tcsetsid() then calls
into an IPC framework.

1 files changed, 7 insertions, 3 deletions

diff --git a/lib/libutil/login_tty.c b/lib/libutil/login_tty.c
index 51299bd..a14e244 100644
--- a/lib/libutil/login_tty.c
+++ b/lib/libutil/login_tty.c
@@ -37,17 +37,21 @@ static char sccsid[] = "@(#)login_tty.c	8.1 (Berkeley) 6/4/93";
 #endif /* LIBC_SCCS and not lint */
 
 #include <sys/param.h>
-#include <sys/ioctl.h>
 
 #include <libutil.h>
 #include <stdlib.h>
+#include <termios.h>
 #include <unistd.h>
 
 int
 login_tty(int fd)
 {
-	(void) setsid();
-	if (ioctl(fd, TIOCSCTTY, (char *)NULL) == -1)
+	pid_t s;
+
+	s = setsid();
+	if (s == -1)
+		return (-1);
+	if (tcsetsid(fd, s) == -1)
 		return (-1);
 	(void) dup2(fd, 0);
 	(void) dup2(fd, 1);