tty_conf.c revision 1.53.2.1
1 /* $NetBSD: tty_conf.c,v 1.53.2.1 2007/03/21 20:11:53 ad 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /*- 40 * Copyright (c) 1982, 1986, 1991, 1993 41 * The Regents of the University of California. All rights reserved. 42 * (c) UNIX System Laboratories, Inc. 43 * All or some portions of this file are derived from material licensed 44 * to the University of California by American Telephone and Telegraph 45 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 46 * the permission of UNIX System Laboratories, Inc. 47 * 48 * Redistribution and use in source and binary forms, with or without 49 * modification, are permitted provided that the following conditions 50 * are met: 51 * 1. Redistributions of source code must retain the above copyright 52 * notice, this list of conditions and the following disclaimer. 53 * 2. Redistributions in binary form must reproduce the above copyright 54 * notice, this list of conditions and the following disclaimer in the 55 * documentation and/or other materials provided with the distribution. 56 * 3. Neither the name of the University nor the names of its contributors 57 * may be used to endorse or promote products derived from this software 58 * without specific prior written permission. 59 * 60 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 61 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 62 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 63 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 64 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 65 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 66 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 67 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 68 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 69 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 70 * SUCH DAMAGE. 71 * 72 * @(#)tty_conf.c 8.5 (Berkeley) 1/9/95 73 */ 74 75 #include <sys/cdefs.h> 76 __KERNEL_RCSID(0, "$NetBSD: tty_conf.c,v 1.53.2.1 2007/03/21 20:11:53 ad Exp $"); 77 78 #include <sys/param.h> 79 #include <sys/systm.h> 80 #include <sys/poll.h> 81 #include <sys/proc.h> 82 #include <sys/tty.h> 83 #include <sys/ttycom.h> 84 #include <sys/conf.h> 85 #include <sys/once.h> 86 #include <sys/mutex.h> 87 #include <sys/queue.h> 88 89 static struct linesw termios_disc = { 90 .l_name = "termios", 91 .l_open = ttylopen, 92 .l_close = ttylclose, 93 .l_read = ttread, 94 .l_write = ttwrite, 95 .l_ioctl = ttynullioctl, 96 .l_rint = ttyinput, 97 .l_start = ttstart, 98 .l_modem = ttymodem, 99 .l_poll = ttpoll 100 }; 101 102 /* 103 * This is for the benefit of old BSD TTY compatbility, but since it is 104 * identical to termios (except for the name), don't bother conditionalizing 105 * it. 106 */ 107 static struct linesw ntty_disc = { /* old NTTYDISC */ 108 .l_name = "ntty", 109 .l_open = ttylopen, 110 .l_close = ttylclose, 111 .l_read = ttread, 112 .l_write = ttwrite, 113 .l_ioctl = ttynullioctl, 114 .l_rint = ttyinput, 115 .l_start = ttstart, 116 .l_modem = ttymodem, 117 .l_poll = ttpoll 118 }; 119 120 static LIST_HEAD(, linesw) ttyldisc_list = LIST_HEAD_INITIALIZER(ttyldisc_head); 121 static kmutex_t ttyldisc_list_lock; 122 123 /* 124 * Note: We don't bother refcounting termios_disc and ntty_disc; they can't 125 * be removed from the list, and termios_disc is likely to have very many 126 * references (could we overflow the count?). 127 */ 128 #define TTYLDISC_ISSTATIC(disc) \ 129 ((disc) == &termios_disc || (disc) == &ntty_disc) 130 131 #define TTYLDISC_HOLD(disc) \ 132 do { \ 133 if (! TTYLDISC_ISSTATIC(disc)) { \ 134 KASSERT((disc)->l_refcnt != UINT_MAX); \ 135 (disc)->l_refcnt++; \ 136 } \ 137 } while (/*CONSTCOND*/0) 138 139 #define TTYLDISC_RELE(disc) \ 140 do { \ 141 if (! TTYLDISC_ISSTATIC(disc)) { \ 142 KASSERT((disc)->l_refcnt != 0); \ 143 (disc)->l_refcnt--; \ 144 } \ 145 } while (/*CONSTCOND*/0) 146 147 #define TTYLDISC_ISINUSE(disc) \ 148 (TTYLDISC_ISSTATIC(disc) || (disc)->l_refcnt != 0) 149 150 /* 151 * Do nothing specific version of line 152 * discipline specific ioctl command. 153 */ 154 /*ARGSUSED*/ 155 int 156 ttynullioctl(struct tty *tp, u_long cmd, void *data, int flags, struct lwp *l) 157 { 158 159 return (EPASSTHROUGH); 160 } 161 162 /* 163 * Return error to line discipline 164 * specific poll call. 165 */ 166 /*ARGSUSED*/ 167 int 168 ttyerrpoll(struct tty *tp, int events, struct lwp *l) 169 { 170 171 return (POLLERR); 172 } 173 174 static ONCE_DECL(ttyldisc_init_once); 175 176 static int 177 ttyldisc_init(void) 178 { 179 180 mutex_init(&ttyldisc_list_lock, MUTEX_DEFAULT, IPL_NONE); 181 182 if (ttyldisc_attach(&termios_disc) != 0) 183 panic("ttyldisc_init: termios_disc"); 184 if (ttyldisc_attach(&ntty_disc) != 0) 185 panic("ttyldisc_init: ntty_disc"); 186 187 return 0; 188 } 189 190 static struct linesw * 191 ttyldisc_lookup_locked(const char *name) 192 { 193 struct linesw *disc; 194 195 LIST_FOREACH(disc, &ttyldisc_list, l_list) { 196 if (strcmp(name, disc->l_name) == 0) 197 return (disc); 198 } 199 200 return (NULL); 201 } 202 203 /* 204 * Look up a line discipline by its name. Caller holds a reference on 205 * the returned line discipline. 206 */ 207 struct linesw * 208 ttyldisc_lookup(const char *name) 209 { 210 struct linesw *disc; 211 212 RUN_ONCE(&ttyldisc_init_once, ttyldisc_init); 213 214 mutex_enter(&ttyldisc_list_lock); 215 disc = ttyldisc_lookup_locked(name); 216 if (disc != NULL) 217 TTYLDISC_HOLD(disc); 218 mutex_exit(&ttyldisc_list_lock); 219 220 return (disc); 221 } 222 223 /* 224 * Look up a line discipline by its legacy number. Caller holds a 225 * reference on the returned line discipline. 226 */ 227 struct linesw * 228 ttyldisc_lookup_bynum(int num) 229 { 230 struct linesw *disc; 231 232 RUN_ONCE(&ttyldisc_init_once, ttyldisc_init); 233 234 mutex_enter(&ttyldisc_list_lock); 235 236 LIST_FOREACH(disc, &ttyldisc_list, l_list) { 237 if (disc->l_no == num) { 238 TTYLDISC_HOLD(disc); 239 mutex_exit(&ttyldisc_list_lock); 240 return (disc); 241 } 242 } 243 244 mutex_exit(&ttyldisc_list_lock); 245 return (NULL); 246 } 247 248 /* 249 * Release a reference on a line discipline previously added by 250 * ttyldisc_lookup() or ttyldisc_lookup_bynum(). 251 */ 252 void 253 ttyldisc_release(struct linesw *disc) 254 { 255 256 if (disc == NULL) 257 return; 258 259 mutex_enter(&ttyldisc_list_lock); 260 TTYLDISC_RELE(disc); 261 mutex_exit(&ttyldisc_list_lock); 262 } 263 264 #define TTYLDISC_LEGACY_NUMBER_MIN 10 265 #define TTYLDISC_LEGACY_NUMBER_MAX INT_MAX 266 267 static void 268 ttyldisc_assign_legacy_number(struct linesw *disc) 269 { 270 static const struct { 271 const char *name; 272 int num; 273 } table[] = { 274 { "termios", TTYDISC }, 275 { "ntty", 2 /* XXX old NTTYDISC */ }, 276 { "tablet", TABLDISC }, 277 { "slip", SLIPDISC }, 278 { "ppp", PPPDISC }, 279 { "strip", STRIPDISC }, 280 { "hdlc", HDLCDISC }, 281 { NULL, 0 } 282 }; 283 struct linesw *ldisc; 284 int i; 285 286 for (i = 0; table[i].name != NULL; i++) { 287 if (strcmp(disc->l_name, table[i].name) == 0) { 288 disc->l_no = table[i].num; 289 return; 290 } 291 } 292 293 disc->l_no = TTYLDISC_LEGACY_NUMBER_MIN; 294 295 LIST_FOREACH(ldisc, &ttyldisc_list, l_list) { 296 if (disc->l_no == ldisc->l_no) { 297 KASSERT(disc->l_no < TTYLDISC_LEGACY_NUMBER_MAX); 298 disc->l_no++; 299 } 300 } 301 } 302 303 /* 304 * Register a line discipline. 305 */ 306 int 307 ttyldisc_attach(struct linesw *disc) 308 { 309 310 KASSERT(disc->l_name != NULL); 311 KASSERT(disc->l_open != NULL); 312 KASSERT(disc->l_close != NULL); 313 KASSERT(disc->l_read != NULL); 314 KASSERT(disc->l_write != NULL); 315 KASSERT(disc->l_ioctl != NULL); 316 KASSERT(disc->l_rint != NULL); 317 KASSERT(disc->l_start != NULL); 318 KASSERT(disc->l_modem != NULL); 319 KASSERT(disc->l_poll != NULL); 320 321 /* You are not allowed to exceed TTLINEDNAMELEN */ 322 if (strlen(disc->l_name) >= TTLINEDNAMELEN) 323 return (ENAMETOOLONG); 324 325 mutex_enter(&ttyldisc_list_lock); 326 327 if (ttyldisc_lookup_locked(disc->l_name) != NULL) { 328 mutex_exit(&ttyldisc_list_lock); 329 return (EEXIST); 330 } 331 332 ttyldisc_assign_legacy_number(disc); 333 LIST_INSERT_HEAD(&ttyldisc_list, disc, l_list); 334 335 mutex_exit(&ttyldisc_list_lock); 336 337 return (0); 338 } 339 340 /* 341 * Remove a line discipline. 342 */ 343 int 344 ttyldisc_detach(struct linesw *disc) 345 { 346 #ifdef DIAGNOSTIC 347 struct linesw *ldisc = ttyldisc_lookup(disc->l_name); 348 349 KASSERT(ldisc != NULL); 350 KASSERT(ldisc == disc); 351 ttyldisc_release(ldisc); 352 #endif 353 354 mutex_enter(&ttyldisc_list_lock); 355 356 if (TTYLDISC_ISINUSE(disc)) { 357 mutex_exit(&ttyldisc_list_lock); 358 return (EBUSY); 359 } 360 361 LIST_REMOVE(disc, l_list); 362 363 mutex_exit(&ttyldisc_list_lock); 364 365 return (0); 366 } 367 368 /* 369 * Return the default line discipline. 370 */ 371 struct linesw * 372 ttyldisc_default(void) 373 { 374 375 return (&termios_disc); 376 } 377
Indexes created Sat Sep 20 22:09:52 GMT 2025