1 /*- 2 * Copyright (c) 1982, 1986, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)tty_tty.c 8.2 (Berkeley) 9/23/93 34 * $FreeBSD: src/sys/kern/tty_tty.c,v 1.30 1999/09/25 18:24:24 phk Exp $ 35 * $DragonFly: src/sys/kern/tty_tty.c,v 1.18 2006/09/10 01:26:39 dillon Exp $ 36 */ 37 38 /* 39 * Indirect driver for controlling tty. 40 */ 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/conf.h> 45 #include <sys/device.h> 46 #include <sys/lock.h> 47 #include <sys/fcntl.h> 48 #include <sys/proc.h> 49 #include <sys/ttycom.h> 50 #include <sys/vnode.h> 51 #include <sys/kernel.h> 52 53 static d_open_t cttyopen; 54 static d_close_t cttyclose; 55 static d_read_t cttyread; 56 static d_write_t cttywrite; 57 static d_ioctl_t cttyioctl; 58 static d_poll_t cttypoll; 59 60 #define CDEV_MAJOR 1 61 /* Don't make this static, since fdesc_vnops uses it. */ 62 struct dev_ops ctty_ops = { 63 { "ctty", CDEV_MAJOR, D_TTY }, 64 .d_open = cttyopen, 65 .d_close = cttyclose, 66 .d_read = cttyread, 67 .d_write = cttywrite, 68 .d_ioctl = cttyioctl, 69 .d_poll = cttypoll, 70 }; 71 72 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL) 73 74 /* 75 * This opens /dev/tty. Because multiple opens of /dev/tty only 76 * generate a single open to the actual tty, the file modes are 77 * locked to FREAD|FWRITE. 78 */ 79 static int 80 cttyopen(struct dev_open_args *ap) 81 { 82 struct proc *p = curproc; 83 struct vnode *ttyvp; 84 int error; 85 86 KKASSERT(p); 87 ttyvp = cttyvp(p); 88 if (ttyvp) { 89 if (ttyvp->v_flag & VCTTYISOPEN) { 90 error = 0; 91 } else { 92 vsetflags(ttyvp, VCTTYISOPEN); 93 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 94 error = VOP_OPEN(ttyvp, FREAD|FWRITE, ap->a_cred, NULL); 95 if (error) 96 vclrflags(ttyvp, VCTTYISOPEN); 97 vn_unlock(ttyvp); 98 } 99 } else { 100 error = ENXIO; 101 } 102 return (error); 103 } 104 105 /* 106 * This closes /dev/tty. Because multiple opens of /dev/tty only 107 * generate a single open to the actual tty, the file modes are 108 * locked to FREAD|FWRITE. 109 */ 110 static int 111 cttyclose(struct dev_close_args *ap) 112 { 113 struct proc *p = curproc; 114 struct vnode *ttyvp; 115 int error; 116 117 KKASSERT(p); 118 ttyvp = cttyvp(p); 119 if (ttyvp == NULL) { 120 /* 121 * The tty may have been TIOCNOTTY'd, don't return an 122 * error on close. We just have nothing to do. 123 */ 124 /* error = EIO; */ 125 error = 0; 126 } else if (ttyvp->v_flag & VCTTYISOPEN) { 127 vclrflags(ttyvp, VCTTYISOPEN); 128 error = vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY); 129 if (error == 0) { 130 error = VOP_CLOSE(ttyvp, FREAD|FWRITE); 131 vn_unlock(ttyvp); 132 } 133 } else { 134 error = 0; 135 } 136 return(error); 137 } 138 139 /* 140 * Read from the controlling terminal (/dev/tty). The tty is refed as 141 * of the cttyvp(), but the ref can get ripped out from under us if 142 * the controlling terminal is revoked while we are blocked on the lock, 143 * so use vget() instead of vn_lock(). 144 */ 145 static int 146 cttyread(struct dev_read_args *ap) 147 { 148 struct proc *p = curproc; 149 struct vnode *ttyvp; 150 int error; 151 152 KKASSERT(p); 153 ttyvp = cttyvp(p); 154 if (ttyvp == NULL) 155 return (EIO); 156 if ((error = vget(ttyvp, LK_EXCLUSIVE | LK_RETRY)) == 0) { 157 error = VOP_READ(ttyvp, ap->a_uio, ap->a_ioflag, NOCRED); 158 vput(ttyvp); 159 } 160 return (error); 161 } 162 163 /* 164 * Read from the controlling terminal (/dev/tty). The tty is refed as 165 * of the cttyvp(), but the ref can get ripped out from under us if 166 * the controlling terminal is revoked while we are blocked on the lock, 167 * so use vget() instead of vn_lock(). 168 */ 169 static int 170 cttywrite(struct dev_write_args *ap) 171 { 172 struct proc *p = curproc; 173 struct vnode *ttyvp; 174 int error; 175 176 KKASSERT(p); 177 ttyvp = cttyvp(p); 178 if (ttyvp == NULL) 179 return (EIO); 180 if ((error = vget(ttyvp, LK_EXCLUSIVE | LK_RETRY)) == 0) { 181 error = VOP_WRITE(ttyvp, ap->a_uio, ap->a_ioflag, NOCRED); 182 vput(ttyvp); 183 } 184 return (error); 185 } 186 187 /*ARGSUSED*/ 188 static int 189 cttyioctl(struct dev_ioctl_args *ap) 190 { 191 struct vnode *ttyvp; 192 struct proc *p = curproc; 193 194 KKASSERT(p); 195 ttyvp = cttyvp(p); 196 if (ttyvp == NULL) 197 return (EIO); 198 /* 199 * Don't allow controlling tty to be set to the controlling tty 200 * (infinite recursion). 201 */ 202 if (ap->a_cmd == TIOCSCTTY) 203 return EINVAL; 204 if (ap->a_cmd == TIOCNOTTY) { 205 if (!SESS_LEADER(p)) { 206 p->p_flag &= ~P_CONTROLT; 207 return (0); 208 } else { 209 return (EINVAL); 210 } 211 } 212 return (VOP_IOCTL(ttyvp, ap->a_cmd, ap->a_data, ap->a_fflag, ap->a_cred)); 213 } 214 215 /*ARGSUSED*/ 216 static int 217 cttypoll(struct dev_poll_args *ap) 218 { 219 cdev_t dev = ap->a_head.a_dev; 220 struct vnode *ttyvp; 221 struct proc *p = curproc; 222 223 KKASSERT(p); 224 ttyvp = cttyvp(p); 225 /* 226 * try operation to get EOF/failure 227 */ 228 if (ttyvp == NULL) 229 ap->a_events = seltrue(dev, ap->a_events); 230 else 231 ap->a_events = VOP_POLL(ttyvp, ap->a_events, p->p_ucred); 232 return(0); 233 } 234 235 static void 236 ctty_drvinit(void *unused __unused) 237 { 238 dev_ops_add(&ctty_ops, 0, 0); 239 make_dev(&ctty_ops, 0, 0, 0, 0666, "tty"); 240 } 241 242 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL) 243