/*      $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 */