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tty_subr.c revision 1.32.6.2 
      1 /*	$NetBSD: tty_subr.c,v 1.32.6.2 2008/09/28 10:40:54 mjf Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1993, 1994 Theo de Raadt
      5  * All rights reserved.
      6  *
      7  * Per Lindqvist <pgd (at) compuram.bbt.se> supplied an almost fully working
      8  * set of true clist functions that this is very loosely based on.
      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 AUTHOR ``AS IS'' AND ANY EXPRESS OR
     20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include <sys/cdefs.h>
     32 __KERNEL_RCSID(0, "$NetBSD: tty_subr.c,v 1.32.6.2 2008/09/28 10:40:54 mjf Exp $");
     33 
     34 #include <sys/param.h>
     35 #include <sys/systm.h>
     36 #include <sys/buf.h>
     37 #include <sys/ioctl.h>
     38 #include <sys/tty.h>
     39 #include <sys/malloc.h>
     40 
     41 MALLOC_DEFINE(M_TTYS, "ttys", "allocated tty structures");
     42 
     43 /*
     44  * At compile time, choose:
     45  * There are two ways the TTY_QUOTE bit can be stored. If QBITS is
     46  * defined we allocate an array of bits -- 1/8th as much memory but
     47  * setbit(), clrbit(), and isset() take more CPU. If QBITS is
     48  * undefined, we just use an array of bytes.
     49  *
     50  * If TTY_QUOTE functionality isn't required by a line discipline,
     51  * it can free c_cq and set it to NULL. This speeds things up,
     52  * and also does not use any extra memory. This is useful for (say)
     53  * a SLIP line discipline that wants a 32K ring buffer for data
     54  * but doesn't need quoting.
     55  */
     56 #define QBITS
     57 
     58 #ifdef QBITS
     59 #define QMEM(n)		((((n)-1)/NBBY)+1)
     60 #else
     61 #define QMEM(n)		(n)
     62 #endif
     63 
     64 #ifdef QBITS
     65 static void	clrbits(u_char *, int, int);
     66 #endif
     67 
     68 /*
     69  * Initialize a particular clist. Ok, they are really ring buffers,
     70  * of the specified length, with/without quoting support.
     71  */
     72 int
     73 clalloc(struct clist *clp, int size, int quot)
     74 {
     75 
     76 	clp->c_cs = malloc(size, M_TTYS, M_WAITOK);
     77 	if (!clp->c_cs)
     78 		return (-1);
     79 	memset(clp->c_cs, 0, size);
     80 
     81 	if(quot) {
     82 		clp->c_cq = malloc(QMEM(size), M_TTYS, M_WAITOK);
     83 		if (!clp->c_cq) {
     84 			free(clp->c_cs, M_TTYS);
     85 			return (-1);
     86 		}
     87 		memset(clp->c_cq, 0, QMEM(size));
     88 	} else
     89 		clp->c_cq = (u_char *)0;
     90 
     91 	clp->c_cf = clp->c_cl = (u_char *)0;
     92 	clp->c_ce = clp->c_cs + size;
     93 	clp->c_cn = size;
     94 	clp->c_cc = 0;
     95 
     96 	return (0);
     97 }
     98 
     99 void
    100 clfree(struct clist *clp)
    101 {
    102 	if(clp->c_cs)
    103 		free(clp->c_cs, M_TTYS);
    104 	if(clp->c_cq)
    105 		free(clp->c_cq, M_TTYS);
    106 	clp->c_cs = clp->c_cq = (u_char *)0;
    107 }
    108 
    109 /*
    110  * Get a character from a clist.
    111  */
    112 int
    113 getc(struct clist *clp)
    114 {
    115 	int c = -1;
    116 	int s;
    117 
    118 	s = spltty();
    119 	if (clp->c_cc == 0)
    120 		goto out;
    121 
    122 	c = *clp->c_cf & 0xff;
    123 	if (clp->c_cq) {
    124 #ifdef QBITS
    125 		if (isset(clp->c_cq, clp->c_cf - clp->c_cs) )
    126 			c |= TTY_QUOTE;
    127 #else
    128 		if (*(clp->c_cf - clp->c_cs + clp->c_cq))
    129 			c |= TTY_QUOTE;
    130 #endif
    131 	}
    132 	*clp->c_cf = 0; /* wipe out to avoid information disclosure */
    133 	if (++clp->c_cf == clp->c_ce)
    134 		clp->c_cf = clp->c_cs;
    135 	if (--clp->c_cc == 0)
    136 		clp->c_cf = clp->c_cl = (u_char *)0;
    137 out:
    138 	splx(s);
    139 	return c;
    140 }
    141 
    142 /*
    143  * Copy clist to buffer.
    144  * Return number of bytes moved.
    145  */
    146 int
    147 q_to_b(struct clist *clp, u_char *cp, int count)
    148 {
    149 	int cc;
    150 	u_char *p = cp;
    151 	int s;
    152 
    153 	s = spltty();
    154 	/* optimize this while loop */
    155 	while (count > 0 && clp->c_cc > 0) {
    156 		cc = clp->c_cl - clp->c_cf;
    157 		if (clp->c_cf >= clp->c_cl)
    158 			cc = clp->c_ce - clp->c_cf;
    159 		if (cc > count)
    160 			cc = count;
    161 		memcpy(p, clp->c_cf, cc);
    162 		count -= cc;
    163 		p += cc;
    164 		clp->c_cc -= cc;
    165 		clp->c_cf += cc;
    166 		if (clp->c_cf == clp->c_ce)
    167 			clp->c_cf = clp->c_cs;
    168 	}
    169 	if (clp->c_cc == 0)
    170 		clp->c_cf = clp->c_cl = (u_char *)0;
    171 	splx(s);
    172 	return p - cp;
    173 }
    174 
    175 /*
    176  * Return count of contiguous characters in clist.
    177  * Stop counting if flag&character is non-null.
    178  */
    179 int
    180 ndqb(struct clist *clp, int flag)
    181 {
    182 	int count = 0;
    183 	int i;
    184 	int cc;
    185 	int s;
    186 
    187 	s = spltty();
    188 	if ((cc = clp->c_cc) == 0)
    189 		goto out;
    190 
    191 	if (flag == 0) {
    192 		count = clp->c_cl - clp->c_cf;
    193 		if (count <= 0)
    194 			count = clp->c_ce - clp->c_cf;
    195 		goto out;
    196 	}
    197 
    198 	i = clp->c_cf - clp->c_cs;
    199 	if (flag & TTY_QUOTE) {
    200 		while (cc-- > 0 && !(clp->c_cs[i++] & (flag & ~TTY_QUOTE) ||
    201 		    isset(clp->c_cq, i))) {
    202 			count++;
    203 			if (i == clp->c_cn)
    204 				break;
    205 		}
    206 	} else {
    207 		while (cc-- > 0 && !(clp->c_cs[i++] & flag)) {
    208 			count++;
    209 			if (i == clp->c_cn)
    210 				break;
    211 		}
    212 	}
    213 out:
    214 	splx(s);
    215 	return count;
    216 }
    217 
    218 /*
    219  * Flush count bytes from clist.
    220  */
    221 void
    222 ndflush(struct clist *clp, int count)
    223 {
    224 	int cc;
    225 	int s;
    226 
    227 	s = spltty();
    228 	if (count == clp->c_cc) {
    229 		clp->c_cc = 0;
    230 		clp->c_cf = clp->c_cl = (u_char *)0;
    231 		goto out;
    232 	}
    233 	/* optimize this while loop */
    234 	while (count > 0 && clp->c_cc > 0) {
    235 		cc = clp->c_cl - clp->c_cf;
    236 		if (clp->c_cf >= clp->c_cl)
    237 			cc = clp->c_ce - clp->c_cf;
    238 		if (cc > count)
    239 			cc = count;
    240 		count -= cc;
    241 		clp->c_cc -= cc;
    242 		clp->c_cf += cc;
    243 		if (clp->c_cf == clp->c_ce)
    244 			clp->c_cf = clp->c_cs;
    245 	}
    246 	if (clp->c_cc == 0)
    247 		clp->c_cf = clp->c_cl = (u_char *)0;
    248 out:
    249 	splx(s);
    250 }
    251 
    252 /*
    253  * Put a character into the output queue.
    254  */
    255 int
    256 putc(int c, struct clist *clp)
    257 {
    258 	int i;
    259 	int s;
    260 
    261 	s = spltty();
    262 	if (clp->c_cc == clp->c_cn)
    263 		goto out;
    264 
    265 	if (clp->c_cc == 0) {
    266 		if (!clp->c_cs) {
    267 #if defined(DIAGNOSTIC) || 1
    268 			printf("putc: required clalloc\n");
    269 #endif
    270 			if(clalloc(clp, 1024, 1)) {
    271 out:
    272 				splx(s);
    273 				return -1;
    274 			}
    275 		}
    276 		clp->c_cf = clp->c_cl = clp->c_cs;
    277 	}
    278 
    279 	*clp->c_cl = c & 0xff;
    280 	i = clp->c_cl - clp->c_cs;
    281 	if (clp->c_cq) {
    282 #ifdef QBITS
    283 		if (c & TTY_QUOTE)
    284 			setbit(clp->c_cq, i);
    285 		else
    286 			clrbit(clp->c_cq, i);
    287 #else
    288 		q = clp->c_cq + i;
    289 		*q = (c & TTY_QUOTE) ? 1 : 0;
    290 #endif
    291 	}
    292 	clp->c_cc++;
    293 	clp->c_cl++;
    294 	if (clp->c_cl == clp->c_ce)
    295 		clp->c_cl = clp->c_cs;
    296 	splx(s);
    297 	return 0;
    298 }
    299 
    300 #ifdef QBITS
    301 /*
    302  * optimized version of
    303  *
    304  * for (i = 0; i < len; i++)
    305  *	clrbit(cp, off + len);
    306  */
    307 static void
    308 clrbits(u_char *cp, int off, int len)
    309 {
    310 	int sby, sbi, eby, ebi;
    311 	int i;
    312 	u_char mask;
    313 
    314 	if(len==1) {
    315 		clrbit(cp, off);
    316 		return;
    317 	}
    318 
    319 	sby = off / NBBY;
    320 	sbi = off % NBBY;
    321 	eby = (off+len) / NBBY;
    322 	ebi = (off+len) % NBBY;
    323 	if (sby == eby) {
    324 		mask = ((1 << (ebi - sbi)) - 1) << sbi;
    325 		cp[sby] &= ~mask;
    326 	} else {
    327 		mask = (1<<sbi) - 1;
    328 		cp[sby++] &= mask;
    329 
    330 		mask = (1<<ebi) - 1;
    331 		cp[eby] &= ~mask;
    332 
    333 		for (i = sby; i < eby; i++)
    334 			cp[i] = 0x00;
    335 	}
    336 }
    337 #endif
    338 
    339 /*
    340  * Copy buffer to clist.
    341  * Return number of bytes not transfered.
    342  */
    343 int
    344 b_to_q(const u_char *cp, int count, struct clist *clp)
    345 {
    346 	int cc;
    347 	const u_char *p = cp;
    348 	int s;
    349 
    350 	if (count <= 0)
    351 		return 0;
    352 
    353 	s = spltty();
    354 	if (clp->c_cc == clp->c_cn)
    355 		goto out;
    356 
    357 	if (clp->c_cc == 0) {
    358 		if (!clp->c_cs) {
    359 #if defined(DIAGNOSTIC) || 1
    360 			printf("b_to_q: required clalloc\n");
    361 #endif
    362 			if(clalloc(clp, 1024, 1))
    363 				goto out;
    364 		}
    365 		clp->c_cf = clp->c_cl = clp->c_cs;
    366 	}
    367 
    368 	/* optimize this while loop */
    369 	while (count > 0 && clp->c_cc < clp->c_cn) {
    370 		cc = clp->c_ce - clp->c_cl;
    371 		if (clp->c_cf > clp->c_cl)
    372 			cc = clp->c_cf - clp->c_cl;
    373 		if (cc > count)
    374 			cc = count;
    375 		memcpy(clp->c_cl, p, cc);
    376 		if (clp->c_cq) {
    377 #ifdef QBITS
    378 			clrbits(clp->c_cq, clp->c_cl - clp->c_cs, cc);
    379 #else
    380 			memset(clp->c_cl - clp->c_cs + clp->c_cq, 0, cc);
    381 #endif
    382 		}
    383 		p += cc;
    384 		count -= cc;
    385 		clp->c_cc += cc;
    386 		clp->c_cl += cc;
    387 		if (clp->c_cl == clp->c_ce)
    388 			clp->c_cl = clp->c_cs;
    389 	}
    390 out:
    391 	splx(s);
    392 	return count;
    393 }
    394 
    395 static int cc;
    396 
    397 /*
    398  * Given a non-NULL pointer into the clist return the pointer
    399  * to the next character in the list or return NULL if no more chars.
    400  *
    401  * Callers must not allow getc's to happen between firstc's and getc's
    402  * so that the pointer becomes invalid.  Note that interrupts are NOT
    403  * masked.
    404  */
    405 u_char *
    406 nextc(struct clist *clp, u_char *cp, int *c)
    407 {
    408 
    409 	if (clp->c_cf == cp) {
    410 		/*
    411 		 * First time initialization.
    412 		 */
    413 		cc = clp->c_cc;
    414 	}
    415 	if (cc == 0 || cp == NULL)
    416 		return NULL;
    417 	if (--cc == 0)
    418 		return NULL;
    419 	if (++cp == clp->c_ce)
    420 		cp = clp->c_cs;
    421 	*c = *cp & 0xff;
    422 	if (clp->c_cq) {
    423 #ifdef QBITS
    424 		if (isset(clp->c_cq, cp - clp->c_cs))
    425 			*c |= TTY_QUOTE;
    426 #else
    427 		if (*(clp->c_cf - clp->c_cs + clp->c_cq))
    428 			*c |= TTY_QUOTE;
    429 #endif
    430 	}
    431 	return cp;
    432 }
    433 
    434 /*
    435  * Given a non-NULL pointer into the clist return the pointer
    436  * to the first character in the list or return NULL if no more chars.
    437  *
    438  * Callers must not allow getc's to happen between firstc's and getc's
    439  * so that the pointer becomes invalid.  Note that interrupts are NOT
    440  * masked.
    441  *
    442  * *c is set to the NEXT character
    443  */
    444 u_char *
    445 firstc(struct clist *clp, int *c)
    446 {
    447 	u_char *cp;
    448 
    449 	cc = clp->c_cc;
    450 	if (cc == 0)
    451 		return NULL;
    452 	cp = clp->c_cf;
    453 	*c = *cp & 0xff;
    454 	if(clp->c_cq) {
    455 #ifdef QBITS
    456 		if (isset(clp->c_cq, cp - clp->c_cs))
    457 			*c |= TTY_QUOTE;
    458 #else
    459 		if (*(cp - clp->c_cs + clp->c_cq))
    460 			*c |= TTY_QUOTE;
    461 #endif
    462 	}
    463 	return clp->c_cf;
    464 }
    465 
    466 /*
    467  * Remove the last character in the clist and return it.
    468  */
    469 int
    470 unputc(struct clist *clp)
    471 {
    472 	unsigned int c = -1;
    473 	int s;
    474 
    475 	s = spltty();
    476 	if (clp->c_cc == 0)
    477 		goto out;
    478 
    479 	if (clp->c_cl == clp->c_cs)
    480 		clp->c_cl = clp->c_ce - 1;
    481 	else
    482 		--clp->c_cl;
    483 	clp->c_cc--;
    484 
    485 	c = *clp->c_cl & 0xff;
    486 	if (clp->c_cq) {
    487 #ifdef QBITS
    488 		if (isset(clp->c_cq, clp->c_cl - clp->c_cs))
    489 			c |= TTY_QUOTE;
    490 #else
    491 		if (*(clp->c_cf - clp->c_cs + clp->c_cq))
    492 			c |= TTY_QUOTE;
    493 #endif
    494 	}
    495 	if (clp->c_cc == 0)
    496 		clp->c_cf = clp->c_cl = (u_char *)0;
    497 out:
    498 	splx(s);
    499 	return c;
    500 }
    501 
    502 /*
    503  * Put the chars in the from queue on the end of the to queue.
    504  */
    505 void
    506 catq(struct clist *from, struct clist *to)
    507 {
    508 	int c;
    509 
    510 	while ((c = getc(from)) != -1)
    511 		putc(c, to);
    512 }
    513