tty_conf.c revision 1.51
1 /* $NetBSD: tty_conf.c,v 1.51 2006/10/12 01:32:19 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2005 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 1.51 2006/10/12 01:32:19 christos 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/lock.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 struct simplelock ttyldisc_list_slock = SIMPLELOCK_INITIALIZER; 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 __unused, u_long cmd __unused, char *data __unused, 157 int flags __unused, struct lwp *l __unused) 158 { 159 160 return (EPASSTHROUGH); 161 } 162 163 /* 164 * Return error to line discipline 165 * specific poll call. 166 */ 167 /*ARGSUSED*/ 168 int 169 ttyerrpoll(struct tty *tp __unused, int events __unused, struct lwp *l __unused) 170 { 171 172 return (POLLERR); 173 } 174 175 static ONCE_DECL(ttyldisc_init_once); 176 177 static int 178 ttyldisc_init(void) 179 { 180 181 if (ttyldisc_attach(&termios_disc) != 0) 182 panic("ttyldisc_init: termios_disc"); 183 if (ttyldisc_attach(&ntty_disc) != 0) 184 panic("ttyldisc_init: ntty_disc"); 185 186 return 0; 187 } 188 189 static struct linesw * 190 ttyldisc_lookup_locked(const char *name) 191 { 192 struct linesw *disc; 193 194 LIST_FOREACH(disc, &ttyldisc_list, l_list) { 195 if (strcmp(name, disc->l_name) == 0) 196 return (disc); 197 } 198 199 return (NULL); 200 } 201 202 /* 203 * Look up a line discipline by its name. Caller holds a reference on 204 * the returned line discipline. 205 */ 206 struct linesw * 207 ttyldisc_lookup(const char *name) 208 { 209 struct linesw *disc; 210 211 RUN_ONCE(&ttyldisc_init_once, ttyldisc_init); 212 213 simple_lock(&ttyldisc_list_slock); 214 disc = ttyldisc_lookup_locked(name); 215 if (disc != NULL) 216 TTYLDISC_HOLD(disc); 217 simple_unlock(&ttyldisc_list_slock); 218 219 return (disc); 220 } 221 222 /* 223 * Look up a line discipline by its legacy number. Caller holds a 224 * reference on the returned line discipline. 225 */ 226 struct linesw * 227 ttyldisc_lookup_bynum(int num) 228 { 229 struct linesw *disc; 230 231 RUN_ONCE(&ttyldisc_init_once, ttyldisc_init); 232 233 simple_lock(&ttyldisc_list_slock); 234 235 LIST_FOREACH(disc, &ttyldisc_list, l_list) { 236 if (disc->l_no == num) { 237 TTYLDISC_HOLD(disc); 238 simple_unlock(&ttyldisc_list_slock); 239 return (disc); 240 } 241 } 242 243 simple_unlock(&ttyldisc_list_slock); 244 return (NULL); 245 } 246 247 /* 248 * Release a reference on a line discipline previously added by 249 * ttyldisc_lookup() or ttyldisc_lookup_bynum(). 250 */ 251 void 252 ttyldisc_release(struct linesw *disc) 253 { 254 255 if (disc == NULL) 256 return; 257 258 simple_lock(&ttyldisc_list_slock); 259 TTYLDISC_RELE(disc); 260 simple_unlock(&ttyldisc_list_slock); 261 } 262 263 #define TTYLDISC_LEGACY_NUMBER_MIN 10 264 #define TTYLDISC_LEGACY_NUMBER_MAX INT_MAX 265 266 static void 267 ttyldisc_assign_legacy_number(struct linesw *disc) 268 { 269 static const struct { 270 const char *name; 271 int num; 272 } table[] = { 273 { "termios", TTYDISC }, 274 { "ntty", 2 /* XXX old NTTYDISC */ }, 275 { "tablet", TABLDISC }, 276 { "slip", SLIPDISC }, 277 { "ppp", PPPDISC }, 278 { "strip", STRIPDISC }, 279 { "hdlc", HDLCDISC }, 280 { NULL, 0 } 281 }; 282 struct linesw *ldisc; 283 int i; 284 285 for (i = 0; table[i].name != NULL; i++) { 286 if (strcmp(disc->l_name, table[i].name) == 0) { 287 disc->l_no = table[i].num; 288 return; 289 } 290 } 291 292 disc->l_no = TTYLDISC_LEGACY_NUMBER_MIN; 293 294 LIST_FOREACH(ldisc, &ttyldisc_list, l_list) { 295 if (disc->l_no == ldisc->l_no) { 296 KASSERT(disc->l_no < TTYLDISC_LEGACY_NUMBER_MAX); 297 disc->l_no++; 298 } 299 } 300 } 301 302 /* 303 * Register a line discipline. 304 */ 305 int 306 ttyldisc_attach(struct linesw *disc) 307 { 308 309 KASSERT(disc->l_name != NULL); 310 KASSERT(disc->l_open != NULL); 311 KASSERT(disc->l_close != NULL); 312 KASSERT(disc->l_read != NULL); 313 KASSERT(disc->l_write != NULL); 314 KASSERT(disc->l_ioctl != NULL); 315 KASSERT(disc->l_rint != NULL); 316 KASSERT(disc->l_start != NULL); 317 KASSERT(disc->l_modem != NULL); 318 KASSERT(disc->l_poll != NULL); 319 320 /* You are not allowed to exceed TTLINEDNAMELEN */ 321 if (strlen(disc->l_name) >= TTLINEDNAMELEN) 322 return (ENAMETOOLONG); 323 324 simple_lock(&ttyldisc_list_slock); 325 326 if (ttyldisc_lookup_locked(disc->l_name) != NULL) { 327 simple_unlock(&ttyldisc_list_slock); 328 return (EEXIST); 329 } 330 331 ttyldisc_assign_legacy_number(disc); 332 LIST_INSERT_HEAD(&ttyldisc_list, disc, l_list); 333 334 simple_unlock(&ttyldisc_list_slock); 335 336 return (0); 337 } 338 339 /* 340 * Remove a line discipline. 341 */ 342 int 343 ttyldisc_detach(struct linesw *disc) 344 { 345 #ifdef DIAGNOSTIC 346 struct linesw *ldisc = ttyldisc_lookup(disc->l_name); 347 348 KASSERT(ldisc != NULL); 349 KASSERT(ldisc == disc); 350 ttyldisc_release(ldisc); 351 #endif 352 353 simple_lock(&ttyldisc_list_slock); 354 355 if (TTYLDISC_ISINUSE(disc)) { 356 simple_unlock(&ttyldisc_list_slock); 357 return (EBUSY); 358 } 359 360 LIST_REMOVE(disc, l_list); 361 362 simple_unlock(&ttyldisc_list_slock); 363 364 return (0); 365 } 366 367 /* 368 * Return the default line discipline. 369 */ 370 struct linesw * 371 ttyldisc_default(void) 372 { 373 374 return (&termios_disc); 375 } 376
Indexes created Mon Sep 22 05:09:51 GMT 2025