sys/kern/tty_bsdpty.c

   1 /*      $NetBSD: tty_bsdpty.c,v 1.15 2009/01/22 14:38:35 yamt Exp $     */
   2
   3 /*-
   4  * Copyright (c) 2004 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  26  * POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __KERNEL_RCSID(0, "$NetBSD: tty_bsdpty.c,v 1.15 2009/01/22 14:38:35 yamt Exp $");
  31
  32 #include "opt_ptm.h"
  33
  34 #ifdef COMPAT_BSDPTY
  35 /* bsd tty implementation for pty multiplexor driver /dev/ptm{,x} */
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/ioctl.h>
  40 #include <sys/lwp.h>
  41 #include <sys/tty.h>
  42 #include <sys/stat.h>
  43 #include <sys/file.h>
  44 #include <sys/uio.h>
  45 #include <sys/kernel.h>
  46 #include <sys/vnode.h>
  47 #include <sys/namei.h>
  48 #include <sys/signalvar.h>
  49 #include <sys/filedesc.h>
  50 #include <sys/conf.h>
  51 #include <sys/poll.h>
  52 #include <sys/pty.h>
  53 #include <sys/kauth.h>
  54
  55 /*
  56  * pts == /dev/tty[pqrs]?
  57  * ptc == /dev/pty[pqrs]?
  58  */
  59
  60 /*
  61  * All this hard-coding is really evil.
  62  */
  63 #define TTY_GID         4
  64 #define TTY_PERM        (S_IRUSR|S_IWUSR|S_IWGRP)
  65 #define TTY_TEMPLATE    "/dev/XtyXX"
  66 #define TTY_NAMESIZE    sizeof(TTY_TEMPLATE)
  67 #define TTY_LETTERS     "pqrstuvwxyzPQRST"
  68 #define TTY_OLD_SUFFIX  "0123456789abcdef"
  69 #define TTY_NEW_SUFFIX  "ghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
  70
  71 static int pty_makename(struct ptm_pty *, struct lwp *, char *, size_t, dev_t,
  72     char);
  73 static int pty_allocvp(struct ptm_pty *, struct lwp *, struct vnode **,
  74     dev_t, char);
  75 static void pty_getvattr(struct ptm_pty *, struct lwp *, struct vattr *);
  76
  77 struct ptm_pty ptm_bsdpty = {
  78         pty_allocvp,
  79         pty_makename,
  80         pty_getvattr,
  81         NULL
  82 };
  83
  84 static int
  85 /*ARGSUSED*/
  86 pty_makename(struct ptm_pty *ptm, struct lwp *l, char *bf,
  87     size_t bufsiz, dev_t dev, char c)
  88 {
  89         size_t nt;
  90         dev_t minor = minor(dev);
  91         const char *suffix;
  92
  93         if (bufsiz < TTY_NAMESIZE)
  94                 return EINVAL;
  95
  96         (void)memcpy(bf, TTY_TEMPLATE, TTY_NAMESIZE);
  97
  98         if (minor < 256) {
  99                 suffix = TTY_OLD_SUFFIX;
 100                 nt = sizeof(TTY_OLD_SUFFIX) - 1;
 101         } else {
 102                 minor -= 256;
 103                 suffix = TTY_NEW_SUFFIX;
 104                 nt = sizeof(TTY_NEW_SUFFIX) - 1;
 105         }
 106
 107         bf[5] = c;
 108         bf[8] = TTY_LETTERS[minor / nt];
 109         bf[9] = suffix[minor % nt];
 110         return 0;
 111 }
 112
 113
 114 static int
 115 /*ARGSUSED*/
 116 pty_allocvp(struct ptm_pty *ptm, struct lwp *l, struct vnode **vp, dev_t dev,
 117     char ms)
 118 {
 119         int error;
 120         struct nameidata nd;
 121         char name[TTY_NAMESIZE];
 122
 123         error = (*ptm->makename)(ptm, l, name, sizeof(name), dev, ms);
 124         if (error)
 125                 return error;
 126
 127         NDINIT(&nd, LOOKUP, NOFOLLOW|LOCKLEAF, UIO_SYSSPACE, name);
 128         if ((error = namei(&nd)) != 0)
 129                 return error;
 130         *vp = nd.ni_vp;
 131         return 0;
 132 }
 133
 134
 135 static void
 136 /*ARGSUSED*/
 137 pty_getvattr(struct ptm_pty *ptm, struct lwp *l, struct vattr *vattr)
 138 {
 139         vattr_null(vattr);
 140         /* get real uid */
 141         vattr->va_uid = kauth_cred_getuid(l->l_cred);
 142         vattr->va_gid = TTY_GID;
 143         vattr->va_mode = TTY_PERM;
 144 }
 145 #endif