1 /* $NetBSD: tty_conf.c,v 1.55 2008/04/28 20:24:05 martin Exp $ */ 2 3 /*- 4 * Copyright (c) 2005, 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /*- 33 * Copyright (c) 1982, 1986, 1991, 1993 34 * The Regents of the University of California. All rights reserved. 35 * (c) UNIX System Laboratories, Inc. 36 * All or some portions of this file are derived from material licensed 37 * to the University of California by American Telephone and Telegraph 38 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 39 * the permission of UNIX System Laboratories, Inc. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 3. Neither the name of the University nor the names of its contributors 50 * may be used to endorse or promote products derived from this software 51 * without specific prior written permission. 52 * 53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 63 * SUCH DAMAGE. 64 * 65 * @(#)tty_conf.c 8.5 (Berkeley) 1/9/95 66 */ 67 68 #include <sys/cdefs.h> 69 __KERNEL_RCSID(0, "$NetBSD: tty_conf.c,v 1.55 2008/04/28 20:24:05 martin Exp $"); 70 71 #include <sys/param.h> 72 #include <sys/systm.h> 73 #include <sys/poll.h> 74 #include <sys/proc.h> 75 #include <sys/tty.h> 76 #include <sys/ttycom.h> 77 #include <sys/conf.h> 78 #include <sys/mutex.h> 79 #include <sys/queue.h> 80 81 static struct linesw termios_disc = { 82 .l_name = "termios", 83 .l_open = ttylopen, 84 .l_close = ttylclose, 85 .l_read = ttread, 86 .l_write = ttwrite, 87 .l_ioctl = ttynullioctl, 88 .l_rint = ttyinput, 89 .l_start = ttstart, 90 .l_modem = ttymodem, 91 .l_poll = ttpoll 92 }; 93 94 /* 95 * This is for the benefit of old BSD TTY compatbility, but since it is 96 * identical to termios (except for the name), don't bother conditionalizing 97 * it. 98 */ 99 static struct linesw ntty_disc = { /* old NTTYDISC */ 100 .l_name = "ntty", 101 .l_open = ttylopen, 102 .l_close = ttylclose, 103 .l_read = ttread, 104 .l_write = ttwrite, 105 .l_ioctl = ttynullioctl, 106 .l_rint = ttyinput, 107 .l_start = ttstart, 108 .l_modem = ttymodem, 109 .l_poll = ttpoll 110 }; 111 112 static LIST_HEAD(, linesw) ttyldisc_list = LIST_HEAD_INITIALIZER(ttyldisc_head); 113 114 /* 115 * Note: We don't bother refcounting termios_disc and ntty_disc; they can't 116 * be removed from the list, and termios_disc is likely to have very many 117 * references (could we overflow the count?). 118 */ 119 #define TTYLDISC_ISSTATIC(disc) \ 120 ((disc) == &termios_disc || (disc) == &ntty_disc) 121 122 #define TTYLDISC_HOLD(disc) \ 123 do { \ 124 if (! TTYLDISC_ISSTATIC(disc)) { \ 125 KASSERT((disc)->l_refcnt != UINT_MAX); \ 126 (disc)->l_refcnt++; \ 127 } \ 128 } while (/*CONSTCOND*/0) 129 130 #define TTYLDISC_RELE(disc) \ 131 do { \ 132 if (! TTYLDISC_ISSTATIC(disc)) { \ 133 KASSERT((disc)->l_refcnt != 0); \ 134 (disc)->l_refcnt--; \ 135 } \ 136 } while (/*CONSTCOND*/0) 137 138 #define TTYLDISC_ISINUSE(disc) \ 139 (TTYLDISC_ISSTATIC(disc) || (disc)->l_refcnt != 0) 140 141 /* 142 * Do nothing specific version of line 143 * discipline specific ioctl command. 144 */ 145 /*ARGSUSED*/ 146 int 147 ttynullioctl(struct tty *tp, u_long cmd, void *data, int flags, struct lwp *l) 148 { 149 150 return (EPASSTHROUGH); 151 } 152 153 /* 154 * Return error to line discipline 155 * specific poll call. 156 */ 157 /*ARGSUSED*/ 158 int 159 ttyerrpoll(struct tty *tp, int events, struct lwp *l) 160 { 161 162 return (POLLERR); 163 } 164 165 void 166 ttyldisc_init(void) 167 { 168 169 if (ttyldisc_attach(&termios_disc) != 0) 170 panic("ttyldisc_init: termios_disc"); 171 if (ttyldisc_attach(&ntty_disc) != 0) 172 panic("ttyldisc_init: ntty_disc"); 173 } 174 175 static struct linesw * 176 ttyldisc_lookup_locked(const char *name) 177 { 178 struct linesw *disc; 179 180 LIST_FOREACH(disc, &ttyldisc_list, l_list) { 181 if (strcmp(name, disc->l_name) == 0) 182 return (disc); 183 } 184 185 return (NULL); 186 } 187 188 /* 189 * Look up a line discipline by its name. Caller holds a reference on 190 * the returned line discipline. 191 */ 192 struct linesw * 193 ttyldisc_lookup(const char *name) 194 { 195 struct linesw *disc; 196 197 mutex_spin_enter(&tty_lock); 198 disc = ttyldisc_lookup_locked(name); 199 if (disc != NULL) 200 TTYLDISC_HOLD(disc); 201 mutex_spin_exit(&tty_lock); 202 203 return (disc); 204 } 205 206 /* 207 * Look up a line discipline by its legacy number. Caller holds a 208 * reference on the returned line discipline. 209 */ 210 struct linesw * 211 ttyldisc_lookup_bynum(int num) 212 { 213 struct linesw *disc; 214 215 mutex_spin_enter(&tty_lock); 216 217 LIST_FOREACH(disc, &ttyldisc_list, l_list) { 218 if (disc->l_no == num) { 219 TTYLDISC_HOLD(disc); 220 mutex_spin_exit(&tty_lock); 221 return (disc); 222 } 223 } 224 225 mutex_spin_exit(&tty_lock); 226 return (NULL); 227 } 228 229 /* 230 * Release a reference on a line discipline previously added by 231 * ttyldisc_lookup() or ttyldisc_lookup_bynum(). 232 */ 233 void 234 ttyldisc_release(struct linesw *disc) 235 { 236 237 if (disc == NULL) 238 return; 239 240 mutex_spin_enter(&tty_lock); 241 TTYLDISC_RELE(disc); 242 mutex_spin_exit(&tty_lock); 243 } 244 245 #define TTYLDISC_LEGACY_NUMBER_MIN 10 246 #define TTYLDISC_LEGACY_NUMBER_MAX INT_MAX 247 248 static void 249 ttyldisc_assign_legacy_number(struct linesw *disc) 250 { 251 static const struct { 252 const char *name; 253 int num; 254 } table[] = { 255 { "termios", TTYDISC }, 256 { "ntty", 2 /* XXX old NTTYDISC */ }, 257 { "tablet", TABLDISC }, 258 { "slip", SLIPDISC }, 259 { "ppp", PPPDISC }, 260 { "strip", STRIPDISC }, 261 { "hdlc", HDLCDISC }, 262 { NULL, 0 } 263 }; 264 struct linesw *ldisc; 265 int i; 266 267 for (i = 0; table[i].name != NULL; i++) { 268 if (strcmp(disc->l_name, table[i].name) == 0) { 269 disc->l_no = table[i].num; 270 return; 271 } 272 } 273 274 disc->l_no = TTYLDISC_LEGACY_NUMBER_MIN; 275 276 LIST_FOREACH(ldisc, &ttyldisc_list, l_list) { 277 if (disc->l_no == ldisc->l_no) { 278 KASSERT(disc->l_no < TTYLDISC_LEGACY_NUMBER_MAX); 279 disc->l_no++; 280 } 281 } 282 } 283 284 /* 285 * Register a line discipline. 286 */ 287 int 288 ttyldisc_attach(struct linesw *disc) 289 { 290 291 KASSERT(disc->l_name != NULL); 292 KASSERT(disc->l_open != NULL); 293 KASSERT(disc->l_close != NULL); 294 KASSERT(disc->l_read != NULL); 295 KASSERT(disc->l_write != NULL); 296 KASSERT(disc->l_ioctl != NULL); 297 KASSERT(disc->l_rint != NULL); 298 KASSERT(disc->l_start != NULL); 299 KASSERT(disc->l_modem != NULL); 300 KASSERT(disc->l_poll != NULL); 301 302 /* You are not allowed to exceed TTLINEDNAMELEN */ 303 if (strlen(disc->l_name) >= TTLINEDNAMELEN) 304 return (ENAMETOOLONG); 305 306 mutex_spin_enter(&tty_lock); 307 308 if (ttyldisc_lookup_locked(disc->l_name) != NULL) { 309 mutex_spin_exit(&tty_lock); 310 return (EEXIST); 311 } 312 313 ttyldisc_assign_legacy_number(disc); 314 LIST_INSERT_HEAD(&ttyldisc_list, disc, l_list); 315 316 mutex_spin_exit(&tty_lock); 317 318 return (0); 319 } 320 321 /* 322 * Remove a line discipline. 323 */ 324 int 325 ttyldisc_detach(struct linesw *disc) 326 { 327 #ifdef DIAGNOSTIC 328 struct linesw *ldisc = ttyldisc_lookup(disc->l_name); 329 330 KASSERT(ldisc != NULL); 331 KASSERT(ldisc == disc); 332 ttyldisc_release(ldisc); 333 #endif 334 335 mutex_spin_enter(&tty_lock); 336 337 if (TTYLDISC_ISINUSE(disc)) { 338 mutex_spin_exit(&tty_lock); 339 return (EBUSY); 340 } 341 342 LIST_REMOVE(disc, l_list); 343 344 mutex_spin_exit(&tty_lock); 345 346 return (0); 347 } 348 349 /* 350 * Return the default line discipline. 351 */ 352 struct linesw * 353 ttyldisc_default(void) 354 { 355 356 return (&termios_disc); 357 } 358