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Annotation of sys/kern/tty_tty.c, Revision 1.1.1.1

1.1       nbrk        1: /*     $OpenBSD: tty_tty.c,v 1.10 2007/03/15 10:22:30 art Exp $        */
                      2: /*     $NetBSD: tty_tty.c,v 1.13 1996/03/30 22:24:46 christos Exp $    */
                      3:
                      4: /*-
                      5:  * Copyright (c) 1982, 1986, 1991, 1993
                      6:  *     The Regents of the University of California.  All rights reserved.
                      7:  *
                      8:  * Redistribution and use in source and binary forms, with or without
                      9:  * modification, are permitted provided that the following conditions
                     10:  * are met:
                     11:  * 1. Redistributions of source code must retain the above copyright
                     12:  *    notice, this list of conditions and the following disclaimer.
                     13:  * 2. Redistributions in binary form must reproduce the above copyright
                     14:  *    notice, this list of conditions and the following disclaimer in the
                     15:  *    documentation and/or other materials provided with the distribution.
                     16:  * 3. Neither the name of the University nor the names of its contributors
                     17:  *    may be used to endorse or promote products derived from this software
                     18:  *    without specific prior written permission.
                     19:  *
                     20:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     21:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     22:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     23:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     24:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     25:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     26:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     27:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     28:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     29:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     30:  * SUCH DAMAGE.
                     31:  *
                     32:  *     @(#)tty_tty.c   8.2 (Berkeley) 9/23/93
                     33:  */
                     34:
                     35: /*
                     36:  * Indirect driver for controlling tty.
                     37:  */
                     38: #include <sys/param.h>
                     39: #include <sys/systm.h>
                     40: #include <sys/ioctl.h>
                     41: #include <sys/proc.h>
                     42: #include <sys/tty.h>
                     43: #include <sys/vnode.h>
                     44: #include <sys/file.h>
                     45: #include <sys/conf.h>
                     46:
                     47:
                     48: #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
                     49:
                     50: /*ARGSUSED*/
                     51: int
                     52: cttyopen(dev_t dev, int flag, int mode, struct proc *p)
                     53: {
                     54:        struct vnode *ttyvp = cttyvp(p);
                     55:        int error;
                     56:
                     57:        if (ttyvp == NULL)
                     58:                return (ENXIO);
                     59:        vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
                     60: #ifdef PARANOID
                     61:        /*
                     62:         * Since group is tty and mode is 620 on most terminal lines
                     63:         * and since sessions protect terminals from processes outside
                     64:         * your session, this check is probably no longer necessary.
                     65:         * Since it inhibits setuid root programs that later switch
                     66:         * to another user from accessing /dev/tty, we have decided
                     67:         * to delete this test. (mckusick 5/93)
                     68:         */
                     69:        error = VOP_ACCESS(ttyvp,
                     70:          (flag&FREAD ? VREAD : 0) | (flag&FWRITE ? VWRITE : 0), p->p_ucred, p);
                     71:        if (!error)
                     72: #endif /* PARANOID */
                     73:                error = VOP_OPEN(ttyvp, flag, NOCRED, p);
                     74:        VOP_UNLOCK(ttyvp, 0, p);
                     75:        return (error);
                     76: }
                     77:
                     78: /*ARGSUSED*/
                     79: int
                     80: cttyread(dev_t dev, struct uio *uio, int flag)
                     81: {
                     82:        struct proc *p = uio->uio_procp;
                     83:        struct vnode *ttyvp = cttyvp(uio->uio_procp);
                     84:        int error;
                     85:
                     86:        if (ttyvp == NULL)
                     87:                return (EIO);
                     88:        vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
                     89:        error = VOP_READ(ttyvp, uio, flag, NOCRED);
                     90:        VOP_UNLOCK(ttyvp, 0, p);
                     91:        return (error);
                     92: }
                     93:
                     94: /*ARGSUSED*/
                     95: int
                     96: cttywrite(dev_t dev, struct uio *uio, int flag)
                     97: {
                     98:        struct proc *p = uio->uio_procp;
                     99:        struct vnode *ttyvp = cttyvp(uio->uio_procp);
                    100:        int error;
                    101:
                    102:        if (ttyvp == NULL)
                    103:                return (EIO);
                    104:        vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY, p);
                    105:        error = VOP_WRITE(ttyvp, uio, flag, NOCRED);
                    106:        VOP_UNLOCK(ttyvp, 0, p);
                    107:        return (error);
                    108: }
                    109:
                    110: /*ARGSUSED*/
                    111: int
                    112: cttyioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
                    113: {
                    114:        struct vnode *ttyvp = cttyvp(p);
                    115:
                    116:        if (ttyvp == NULL)
                    117:                return (EIO);
                    118:        if (cmd == TIOCSCTTY)           /* XXX */
                    119:                return (EINVAL);
                    120:        if (cmd == TIOCNOTTY) {
                    121:                if (!SESS_LEADER(p)) {
                    122:                        atomic_clearbits_int(&p->p_flag, P_CONTROLT);
                    123:                        return (0);
                    124:                } else
                    125:                        return (EINVAL);
                    126:        }
                    127:        return (VOP_IOCTL(ttyvp, cmd, addr, flag, NOCRED, p));
                    128: }
                    129:
                    130: /*ARGSUSED*/
                    131: int
                    132: cttypoll(dev_t dev, int events, struct proc *p)
                    133: {
                    134:        struct vnode *ttyvp = cttyvp(p);
                    135:
                    136:        if (ttyvp == NULL)      /* try operation to get EOF/failure */
                    137:                return (seltrue(dev, events, p));
                    138:        return (VOP_POLL(ttyvp, events, p));
                    139: }