tty_conf.c revision 1.53.2.2
1 /* $NetBSD: tty_conf.c,v 1.53.2.2 2007/07/15 22:16:34 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 1.53.2.2 2007/07/15 22:16:34 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/mutex.h> 86 #include <sys/queue.h> 87 88 static struct linesw termios_disc = { 89 .l_name = "termios", 90 .l_open = ttylopen, 91 .l_close = ttylclose, 92 .l_read = ttread, 93 .l_write = ttwrite, 94 .l_ioctl = ttynullioctl, 95 .l_rint = ttyinput, 96 .l_start = ttstart, 97 .l_modem = ttymodem, 98 .l_poll = ttpoll 99 }; 100 101 /* 102 * This is for the benefit of old BSD TTY compatbility, but since it is 103 * identical to termios (except for the name), don't bother conditionalizing 104 * it. 105 */ 106 static struct linesw ntty_disc = { /* old NTTYDISC */ 107 .l_name = "ntty", 108 .l_open = ttylopen, 109 .l_close = ttylclose, 110 .l_read = ttread, 111 .l_write = ttwrite, 112 .l_ioctl = ttynullioctl, 113 .l_rint = ttyinput, 114 .l_start = ttstart, 115 .l_modem = ttymodem, 116 .l_poll = ttpoll 117 }; 118 119 static LIST_HEAD(, linesw) ttyldisc_list = LIST_HEAD_INITIALIZER(ttyldisc_head); 120 static kmutex_t ttyldisc_list_lock; 121 122 /* 123 * Note: We don't bother refcounting termios_disc and ntty_disc; they can't 124 * be removed from the list, and termios_disc is likely to have very many 125 * references (could we overflow the count?). 126 */ 127 #define TTYLDISC_ISSTATIC(disc) \ 128 ((disc) == &termios_disc || (disc) == &ntty_disc) 129 130 #define TTYLDISC_HOLD(disc) \ 131 do { \ 132 if (! TTYLDISC_ISSTATIC(disc)) { \ 133 KASSERT((disc)->l_refcnt != UINT_MAX); \ 134 (disc)->l_refcnt++; \ 135 } \ 136 } while (/*CONSTCOND*/0) 137 138 #define TTYLDISC_RELE(disc) \ 139 do { \ 140 if (! TTYLDISC_ISSTATIC(disc)) { \ 141 KASSERT((disc)->l_refcnt != 0); \ 142 (disc)->l_refcnt--; \ 143 } \ 144 } while (/*CONSTCOND*/0) 145 146 #define TTYLDISC_ISINUSE(disc) \ 147 (TTYLDISC_ISSTATIC(disc) || (disc)->l_refcnt != 0) 148 149 /* 150 * Do nothing specific version of line 151 * discipline specific ioctl command. 152 */ 153 /*ARGSUSED*/ 154 int 155 ttynullioctl(struct tty *tp, u_long cmd, void *data, int flags, struct lwp *l) 156 { 157 158 return (EPASSTHROUGH); 159 } 160 161 /* 162 * Return error to line discipline 163 * specific poll call. 164 */ 165 /*ARGSUSED*/ 166 int 167 ttyerrpoll(struct tty *tp, int events, struct lwp *l) 168 { 169 170 return (POLLERR); 171 } 172 173 void 174 ttyldisc_init(void) 175 { 176 177 mutex_init(&ttyldisc_list_lock, MUTEX_DEFAULT, IPL_NONE); 178 179 if (ttyldisc_attach(&termios_disc) != 0) 180 panic("ttyldisc_init: termios_disc"); 181 if (ttyldisc_attach(&ntty_disc) != 0) 182 panic("ttyldisc_init: ntty_disc"); 183 } 184 185 static struct linesw * 186 ttyldisc_lookup_locked(const char *name) 187 { 188 struct linesw *disc; 189 190 LIST_FOREACH(disc, &ttyldisc_list, l_list) { 191 if (strcmp(name, disc->l_name) == 0) 192 return (disc); 193 } 194 195 return (NULL); 196 } 197 198 /* 199 * Look up a line discipline by its name. Caller holds a reference on 200 * the returned line discipline. 201 */ 202 struct linesw * 203 ttyldisc_lookup(const char *name) 204 { 205 struct linesw *disc; 206 207 mutex_enter(&ttyldisc_list_lock); 208 disc = ttyldisc_lookup_locked(name); 209 if (disc != NULL) 210 TTYLDISC_HOLD(disc); 211 mutex_exit(&ttyldisc_list_lock); 212 213 return (disc); 214 } 215 216 /* 217 * Look up a line discipline by its legacy number. Caller holds a 218 * reference on the returned line discipline. 219 */ 220 struct linesw * 221 ttyldisc_lookup_bynum(int num) 222 { 223 struct linesw *disc; 224 225 mutex_enter(&ttyldisc_list_lock); 226 227 LIST_FOREACH(disc, &ttyldisc_list, l_list) { 228 if (disc->l_no == num) { 229 TTYLDISC_HOLD(disc); 230 mutex_exit(&ttyldisc_list_lock); 231 return (disc); 232 } 233 } 234 235 mutex_exit(&ttyldisc_list_lock); 236 return (NULL); 237 } 238 239 /* 240 * Release a reference on a line discipline previously added by 241 * ttyldisc_lookup() or ttyldisc_lookup_bynum(). 242 */ 243 void 244 ttyldisc_release(struct linesw *disc) 245 { 246 247 if (disc == NULL) 248 return; 249 250 mutex_enter(&ttyldisc_list_lock); 251 TTYLDISC_RELE(disc); 252 mutex_exit(&ttyldisc_list_lock); 253 } 254 255 #define TTYLDISC_LEGACY_NUMBER_MIN 10 256 #define TTYLDISC_LEGACY_NUMBER_MAX INT_MAX 257 258 static void 259 ttyldisc_assign_legacy_number(struct linesw *disc) 260 { 261 static const struct { 262 const char *name; 263 int num; 264 } table[] = { 265 { "termios", TTYDISC }, 266 { "ntty", 2 /* XXX old NTTYDISC */ }, 267 { "tablet", TABLDISC }, 268 { "slip", SLIPDISC }, 269 { "ppp", PPPDISC }, 270 { "strip", STRIPDISC }, 271 { "hdlc", HDLCDISC }, 272 { NULL, 0 } 273 }; 274 struct linesw *ldisc; 275 int i; 276 277 for (i = 0; table[i].name != NULL; i++) { 278 if (strcmp(disc->l_name, table[i].name) == 0) { 279 disc->l_no = table[i].num; 280 return; 281 } 282 } 283 284 disc->l_no = TTYLDISC_LEGACY_NUMBER_MIN; 285 286 LIST_FOREACH(ldisc, &ttyldisc_list, l_list) { 287 if (disc->l_no == ldisc->l_no) { 288 KASSERT(disc->l_no < TTYLDISC_LEGACY_NUMBER_MAX); 289 disc->l_no++; 290 } 291 } 292 } 293 294 /* 295 * Register a line discipline. 296 */ 297 int 298 ttyldisc_attach(struct linesw *disc) 299 { 300 301 KASSERT(disc->l_name != NULL); 302 KASSERT(disc->l_open != NULL); 303 KASSERT(disc->l_close != NULL); 304 KASSERT(disc->l_read != NULL); 305 KASSERT(disc->l_write != NULL); 306 KASSERT(disc->l_ioctl != NULL); 307 KASSERT(disc->l_rint != NULL); 308 KASSERT(disc->l_start != NULL); 309 KASSERT(disc->l_modem != NULL); 310 KASSERT(disc->l_poll != NULL); 311 312 /* You are not allowed to exceed TTLINEDNAMELEN */ 313 if (strlen(disc->l_name) >= TTLINEDNAMELEN) 314 return (ENAMETOOLONG); 315 316 mutex_enter(&ttyldisc_list_lock); 317 318 if (ttyldisc_lookup_locked(disc->l_name) != NULL) { 319 mutex_exit(&ttyldisc_list_lock); 320 return (EEXIST); 321 } 322 323 ttyldisc_assign_legacy_number(disc); 324 LIST_INSERT_HEAD(&ttyldisc_list, disc, l_list); 325 326 mutex_exit(&ttyldisc_list_lock); 327 328 return (0); 329 } 330 331 /* 332 * Remove a line discipline. 333 */ 334 int 335 ttyldisc_detach(struct linesw *disc) 336 { 337 #ifdef DIAGNOSTIC 338 struct linesw *ldisc = ttyldisc_lookup(disc->l_name); 339 340 KASSERT(ldisc != NULL); 341 KASSERT(ldisc == disc); 342 ttyldisc_release(ldisc); 343 #endif 344 345 mutex_enter(&ttyldisc_list_lock); 346 347 if (TTYLDISC_ISINUSE(disc)) { 348 mutex_exit(&ttyldisc_list_lock); 349 return (EBUSY); 350 } 351 352 LIST_REMOVE(disc, l_list); 353 354 mutex_exit(&ttyldisc_list_lock); 355 356 return (0); 357 } 358 359 /* 360 * Return the default line discipline. 361 */ 362 struct linesw * 363 ttyldisc_default(void) 364 { 365 366 return (&termios_disc); 367 } 368
Indexes created Sun Sep 21 20:09:37 GMT 2025