This is xnu-8019. See this file in:
/*
 * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1997 Apple Computer, Inc. All Rights Reserved */
/*
 * Copyright (c) 1993, 1994 Theo de Raadt
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

/*
 * We use the NetBSD based clist system, it is much more efficient than the
 * old style clist stuff used by free bsd.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ioctl.h>
#include <sys/tty.h>
#include <sys/malloc.h>


/*
 * At compile time, choose:
 * There are two ways the TTY_QUOTE bit can be stored. If QBITS is
 * defined we allocate an array of bits -- 1/8th as much memory but
 * setbit(), clrbit(), and isset() take more cpu. If QBITS is
 * undefined, we just use an array of bytes.
 *
 * If TTY_QUOTE functionality isn't required by a line discipline,
 * it can free c_cq and set it to NULL. This speeds things up,
 * and also does not use any extra memory. This is useful for (say)
 * a SLIP line discipline that wants a 32K ring buffer for data
 * but doesn't need quoting.
 */
#define QBITS

#ifdef QBITS
#define QMEM(n)         ((((n)-1)/NBBY)+1)
#else
#define QMEM(n)         (n)
#endif


/*
 * Initialize clists.
 */
void
cinit(void)
{
}

/*
 * Initialize a particular clist. Ok, they are really ring buffers,
 * of the specified length, with/without quoting support.
 */
int
clalloc(struct clist *clp, int size, int quot)
{
	clp->c_cs = kalloc_data(size, Z_WAITOK | Z_ZERO);
	if (!clp->c_cs) {
		return -1;
	}

	if (quot) {
		clp->c_cq = kalloc_data(QMEM(size), Z_WAITOK | Z_ZERO);
		if (!clp->c_cq) {
			kfree_data(clp->c_cs, size);
			return -1;
		}
	} else {
		clp->c_cq = (u_char *)0;
	}

	clp->c_cf = clp->c_cl = (u_char *)0;
	clp->c_ce = clp->c_cs + size;
	clp->c_cn = size;
	clp->c_cc = 0;
	return 0;
}

void
clfree(struct clist *clp)
{
	if (clp->c_cs) {
		kfree_data(clp->c_cs, clp->c_cn);
	}
	if (clp->c_cq) {
		kfree_data(clp->c_cq, QMEM(clp->c_cn));
	}
	clp->c_cs = clp->c_cq = (u_char *)0;
}


/*
 * Get a character from a clist.
 */
int
getc(struct clist *clp)
{
	int c = -1;

	if (clp->c_cc == 0) {
		goto out;
	}

	c = *clp->c_cf & 0xff;
	if (clp->c_cq) {
#ifdef QBITS
		if (isset(clp->c_cq, clp->c_cf - clp->c_cs)) {
			c |= TTY_QUOTE;
		}
#else
		if (*(clp->c_cf - clp->c_cs + clp->c_cq)) {
			c |= TTY_QUOTE;
		}
#endif
	}
	if (++clp->c_cf == clp->c_ce) {
		clp->c_cf = clp->c_cs;
	}
	if (--clp->c_cc == 0) {
		clp->c_cf = clp->c_cl = (u_char *)0;
	}
out:
	return c;
}

/*
 * Copy clist to buffer.
 * Return number of bytes moved.
 */
int
q_to_b(struct clist *clp, u_char *cp, int count)
{
	size_t cc;
	u_char *p = cp;

	/* optimize this while loop */
	while (count > 0 && clp->c_cc > 0) {
		cc = clp->c_cl - clp->c_cf;
		if (clp->c_cf >= clp->c_cl) {
			cc = clp->c_ce - clp->c_cf;
		}
		if (cc > INT_MAX || (int)cc > count) {
			cc = count;
		}
		bcopy(clp->c_cf, p, cc);
		count -= cc;
		p += cc;
		clp->c_cc -= cc;
		clp->c_cf += cc;
		if (clp->c_cf == clp->c_ce) {
			clp->c_cf = clp->c_cs;
		}
	}
	if (clp->c_cc == 0) {
		clp->c_cf = clp->c_cl = (u_char *)0;
	}
	return (int)MIN(INT32_MAX, p - cp);
}

/*
 * Return count of contiguous characters in clist.
 * Stop counting if flag&character is non-null.
 */
int
ndqb(struct clist *clp, int flag)
{
	size_t count = 0;
	size_t i;
	int cc;

	if ((cc = clp->c_cc) == 0) {
		goto out;
	}

	if (flag == 0) {
		count = clp->c_cl - clp->c_cf;
		if (count <= 0) {
			count = clp->c_ce - clp->c_cf;
		}
		goto out;
	}

	i = clp->c_cf - clp->c_cs;
	if (i > INT_MAX) {
		return 0;
	}
	if (flag & TTY_QUOTE) {
		while (cc-- > 0 && !(clp->c_cs[i++] & (flag & ~TTY_QUOTE) ||
		    isset(clp->c_cq, i))) {
			count++;
			if ((int)i == clp->c_cn) {
				break;
			}
		}
	} else {
		while (cc-- > 0 && !(clp->c_cs[i++] & flag)) {
			count++;
			if ((int)i == clp->c_cn) {
				break;
			}
		}
	}
out:
	if (count > INT_MAX) {
		return 0;
	}
	return (int)count;
}

/*
 * Flush count bytes from clist.
 */
void
ndflush(struct clist *clp, int count)
{
	size_t cc;

	if (count == clp->c_cc) {
		clp->c_cc = 0;
		clp->c_cf = clp->c_cl = (u_char *)0;
		return;
	}
	/* optimize this while loop */
	while (count > 0 && clp->c_cc > 0) {
		cc = clp->c_cl - clp->c_cf;
		if (clp->c_cf >= clp->c_cl) {
			cc = clp->c_ce - clp->c_cf;
		}
		if (cc > INT_MAX || (int)cc > count) {
			cc = count;
		}
		count -= cc;
		clp->c_cc -= cc;
		clp->c_cf += cc;
		if (clp->c_cf == clp->c_ce) {
			clp->c_cf = clp->c_cs;
		}
	}
	if (clp->c_cc == 0) {
		clp->c_cf = clp->c_cl = (u_char *)0;
	}
}

/*
 * Put a character into the output queue.
 */
int
putc(int c, struct clist *clp)
{
	size_t i;

	if (clp->c_cc == 0) {
		if (!clp->c_cs) {
#if DIAGNOSTIC
			//printf("putc: required clalloc\n");
#endif
			if (clalloc(clp, 1024, 1)) {
				return -1;
			}
		}
		clp->c_cf = clp->c_cl = clp->c_cs;
	}

	if (clp->c_cc == clp->c_cn) {
		return -1;
	}

	*clp->c_cl = c & 0xff;
	i = clp->c_cl - clp->c_cs;
	if (i > INT_MAX) {
		return -1;
	}
	if (clp->c_cq) {
#ifdef QBITS
		if (c & TTY_QUOTE) {
			setbit(clp->c_cq, i);
		} else {
			clrbit(clp->c_cq, i);
		}
#else
		q = clp->c_cq + i;
		*q = (c & TTY_QUOTE) ? 1 : 0;
#endif
	}
	clp->c_cc++;
	clp->c_cl++;
	if (clp->c_cl == clp->c_ce) {
		clp->c_cl = clp->c_cs;
	}
	return 0;
}

#ifdef QBITS
/*
 * optimized version of
 *
 * for (i = 0; i < len; i++)
 *	clrbit(cp, off + len);
 */
void
clrbits(u_char *cp, int off, int len)
{
	int sby, sbi, eby, ebi;
	int i;
	u_char mask;

	if (len == 1) {
		clrbit(cp, off);
		return;
	}

	sby = off / NBBY;
	sbi = off % NBBY;
	eby = (off + len) / NBBY;
	ebi = (off + len) % NBBY;
	if (sby == eby) {
		mask = (u_char)(((1 << (ebi - sbi)) - 1) << sbi);
		cp[sby] &= ~mask;
	} else {
		mask = (u_char)((1 << sbi) - 1);
		cp[sby++] &= mask;

		mask = (u_char)((1 << ebi) - 1);
		/* handle remainder bits, if any, for a non-0 ebi value */
		if (mask) {
			cp[eby] &= ~mask;
		}

		for (i = sby; i < eby; i++) {
			cp[i] = 0x00;
		}
	}
}
#endif

/*
 * Copy buffer to clist.
 * Return number of bytes not transfered.
 */
int
b_to_q(const u_char *cp, int count, struct clist *clp)
{
	size_t cc;
	const u_char *p = cp;

	if (count <= 0) {
		return 0;
	}


	if (clp->c_cc == 0) {
		if (!clp->c_cs) {
#if DIAGNOSTIC
			printf("b_to_q: required clalloc\n");
#endif
			if (clalloc(clp, 1024, 1)) {
				goto out;
			}
		}
		clp->c_cf = clp->c_cl = clp->c_cs;
	}

	if (clp->c_cc == clp->c_cn) {
		goto out;
	}

	/* optimize this while loop */
	while (count > 0 && clp->c_cc < clp->c_cn) {
		cc = clp->c_ce - clp->c_cl;
		if (clp->c_cf > clp->c_cl) {
			cc = clp->c_cf - clp->c_cl;
		}
		if (cc > INT_MAX || (int)cc > count) {
			cc = count;
		}
		bcopy(p, clp->c_cl, cc);
		if (clp->c_cq) {
#ifdef QBITS
			if (clp->c_cl - clp->c_cs > INT_MAX || cc > INT_MAX) {
				count = 0;
				goto out;
			}
			clrbits(clp->c_cq, (int)(clp->c_cl - clp->c_cs), (int)cc);
#else
			bzero(clp->c_cl - clp->c_cs + clp->c_cq, cc);
#endif
		}
		p += cc;
		count -= cc;
		clp->c_cc += cc;
		clp->c_cl += cc;
		if (clp->c_cl == clp->c_ce) {
			clp->c_cl = clp->c_cs;
		}
	}
out:
	return count;
}

static int cc;

/*
 * Given a non-NULL pointer into the clist return the pointer
 * to the next character in the list or return NULL if no more chars.
 *
 * Callers must not allow getc's to happen between firstc's and getc's
 * so that the pointer becomes invalid.  Note that interrupts are NOT
 * masked.
 */
u_char *
nextc(struct clist *clp, u_char *cp, int *c)
{
	if (clp->c_cf == cp) {
		/*
		 * First time initialization.
		 */
		cc = clp->c_cc;
	}
	if (cc == 0 || cp == NULL) {
		return NULL;
	}
	if (--cc == 0) {
		return NULL;
	}
	if (++cp == clp->c_ce) {
		cp = clp->c_cs;
	}
	*c = *cp & 0xff;
	if (clp->c_cq) {
#ifdef QBITS
		if (isset(clp->c_cq, cp - clp->c_cs)) {
			*c |= TTY_QUOTE;
		}
#else
		if (*(clp->c_cf - clp->c_cs + clp->c_cq)) {
			*c |= TTY_QUOTE;
		}
#endif
	}
	return cp;
}

/*
 * Given a non-NULL pointer into the clist return the pointer
 * to the first character in the list or return NULL if no more chars.
 *
 * Callers must not allow getc's to happen between firstc's and getc's
 * so that the pointer becomes invalid.  Note that interrupts are NOT
 * masked.
 *
 * *c is set to the NEXT character
 */
u_char *
firstc(struct clist *clp, int *c)
{
	u_char *cp;

	cc = clp->c_cc;
	if (cc == 0) {
		return NULL;
	}
	cp = clp->c_cf;
	*c = *cp & 0xff;
	if (clp->c_cq) {
#ifdef QBITS
		if (isset(clp->c_cq, cp - clp->c_cs)) {
			*c |= TTY_QUOTE;
		}
#else
		if (*(cp - clp->c_cs + clp->c_cq)) {
			*c |= TTY_QUOTE;
		}
#endif
	}
	return clp->c_cf;
}

/*
 * Remove the last character in the clist and return it.
 */
int
unputc(struct clist *clp)
{
	unsigned int c = -1;

	if (clp->c_cc == 0) {
		goto out;
	}

	if (clp->c_cl == clp->c_cs) {
		clp->c_cl = clp->c_ce - 1;
	} else {
		--clp->c_cl;
	}
	clp->c_cc--;

	c = *clp->c_cl & 0xff;
	if (clp->c_cq) {
#ifdef QBITS
		if (isset(clp->c_cq, clp->c_cl - clp->c_cs)) {
			c |= TTY_QUOTE;
		}
#else
		if (*(clp->c_cf - clp->c_cs + clp->c_cq)) {
			c |= TTY_QUOTE;
		}
#endif
	}
	if (clp->c_cc == 0) {
		clp->c_cf = clp->c_cl = (u_char *)0;
	}
out:
	return c;
}

/*
 * Put the chars in the from queue on the end of the to queue.
 */
void
catq(struct clist *from, struct clist *to)
{
	int c;

	while ((c = getc(from)) != -1) {
		putc(c, to);
	}
}