/*      $NetBSD: tty_bsdpty.c,v 1.20 2014/04/04 18:11:58 christos Exp $ */

/*-
* Copyright (c) 2004 The NetBSD Foundation, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: tty_bsdpty.c,v 1.20 2014/04/04 18:11:58 christos Exp $");

#include "opt_ptm.h"

#ifndef NO_DEV_PTM
#ifdef COMPAT_BSDPTY
/* bsd tty implementation for pty multiplexor driver /dev/ptm{,x} */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ioctl.h>
#include <sys/lwp.h>
#include <sys/tty.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/uio.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/namei.h>
#include <sys/signalvar.h>
#include <sys/filedesc.h>
#include <sys/conf.h>
#include <sys/poll.h>
#include <sys/pty.h>
#include <sys/kauth.h>

/*
* pts == /dev/tty[pqrs]?
* ptc == /dev/pty[pqrs]?
*/

/*
* All this hard-coding is really evil.
*/
#define TTY_GID         4
#define TTY_PERM        (S_IRUSR|S_IWUSR|S_IWGRP)
#define TTY_TEMPLATE    "/dev/XtyXX"
#define TTY_NAMESIZE    sizeof(TTY_TEMPLATE)
#define TTY_LETTERS     "pqrstuvwxyzPQRST"
#define TTY_OLD_SUFFIX  "0123456789abcdef"
#define TTY_NEW_SUFFIX  "ghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"

static int pty_makename(struct mount *, struct lwp *, char *, size_t, dev_t,
   char);
static int pty_allocvp(struct mount *, struct lwp *, struct vnode **,
   dev_t, char);
static void pty_getvattr(struct mount *, struct lwp *, struct vattr *);
static int pty__getmp(struct lwp *, struct mount **);

struct ptm_pty ptm_bsdpty = {
       pty_allocvp,
       pty_makename,
       pty_getvattr,
       pty__getmp,
};

static int
/*ARGSUSED*/
pty_makename(struct mount *mp, struct lwp *l, char *bf,
   size_t bufsiz, dev_t dev, char c)
{
       size_t nt;
       dev_t minor = minor(dev);
       const char *suffix;

       if (bufsiz < TTY_NAMESIZE)
               return EINVAL;

       (void)memcpy(bf, TTY_TEMPLATE, TTY_NAMESIZE);

       if (minor < 256) {
               suffix = TTY_OLD_SUFFIX;
               nt = sizeof(TTY_OLD_SUFFIX) - 1;
       } else {
               minor -= 256;
               suffix = TTY_NEW_SUFFIX;
               nt = sizeof(TTY_NEW_SUFFIX) - 1;
       }

       bf[5] = c;
       bf[8] = TTY_LETTERS[minor / nt];
       bf[9] = suffix[minor % nt];
       return 0;
}


static int
/*ARGSUSED*/
pty_allocvp(struct mount *mp, struct lwp *l, struct vnode **vp, dev_t dev,
   char ms)
{
       int error;
       struct pathbuf *pb;
       struct nameidata nd;
       char name[TTY_NAMESIZE];

       error = pty_makename(NULL, l, name, sizeof(name), dev, ms);
       if (error)
               return error;

       pb = pathbuf_create(name);
       if (pb == NULL) {
               return ENOMEM;
       }

       NDINIT(&nd, LOOKUP, NOFOLLOW|LOCKLEAF, pb);
       if ((error = namei(&nd)) != 0) {
               pathbuf_destroy(pb);
               return error;
       }
       *vp = nd.ni_vp;
       pathbuf_destroy(pb);
       return 0;
}


static void
/*ARGSUSED*/
pty_getvattr(struct mount *mp, struct lwp *l, struct vattr *vattr)
{
       vattr_null(vattr);
       /* get real uid */
       vattr->va_uid = kauth_cred_getuid(l->l_cred);
       vattr->va_gid = TTY_GID;
       vattr->va_mode = TTY_PERM;
}

static int
pty__getmp(struct lwp *l __unused, struct mount **mpp)
{
       *mpp = 0;
       return 0;
}

#endif /* COMPAT_BSDPTY */
#endif /* NO_DEV_PTM */