xref: /onnv-gate/usr/src/cmd/sh/stak.c (revision 0)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 1992 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28*0Sstevel@tonic-gate /*	  All Rights Reserved  	*/
29*0Sstevel@tonic-gate 
30*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
31*0Sstevel@tonic-gate /*
32*0Sstevel@tonic-gate  * UNIX shell
33*0Sstevel@tonic-gate  */
34*0Sstevel@tonic-gate 
35*0Sstevel@tonic-gate #include	"defs.h"
36*0Sstevel@tonic-gate 
37*0Sstevel@tonic-gate 
38*0Sstevel@tonic-gate /* ========	storage allocation	======== */
39*0Sstevel@tonic-gate 
40*0Sstevel@tonic-gate unsigned char *
41*0Sstevel@tonic-gate getstak(asize)			/* allocate requested stack */
42*0Sstevel@tonic-gate int	asize;
43*0Sstevel@tonic-gate {
44*0Sstevel@tonic-gate 	register unsigned char	*oldstak;
45*0Sstevel@tonic-gate 	register int	size;
46*0Sstevel@tonic-gate 
47*0Sstevel@tonic-gate 	size = round(asize, BYTESPERWORD);
48*0Sstevel@tonic-gate 	oldstak = stakbot;
49*0Sstevel@tonic-gate 	staktop = stakbot += size;
50*0Sstevel@tonic-gate 	if (staktop >= brkend)
51*0Sstevel@tonic-gate 		growstak(staktop);
52*0Sstevel@tonic-gate 	return(oldstak);
53*0Sstevel@tonic-gate }
54*0Sstevel@tonic-gate 
55*0Sstevel@tonic-gate /*
56*0Sstevel@tonic-gate  * set up stack for local use
57*0Sstevel@tonic-gate  * should be followed by `endstak'
58*0Sstevel@tonic-gate  */
59*0Sstevel@tonic-gate unsigned char *
60*0Sstevel@tonic-gate locstak()
61*0Sstevel@tonic-gate {
62*0Sstevel@tonic-gate 	if (brkend - stakbot < BRKINCR)
63*0Sstevel@tonic-gate 	{
64*0Sstevel@tonic-gate 		if (setbrk(brkincr) == -1)
65*0Sstevel@tonic-gate 			error(nostack);
66*0Sstevel@tonic-gate 		if (brkincr < BRKMAX)
67*0Sstevel@tonic-gate 			brkincr += 256;
68*0Sstevel@tonic-gate 	}
69*0Sstevel@tonic-gate 	return(stakbot);
70*0Sstevel@tonic-gate }
71*0Sstevel@tonic-gate 
72*0Sstevel@tonic-gate void
73*0Sstevel@tonic-gate growstak(newtop)
74*0Sstevel@tonic-gate unsigned char	*newtop;
75*0Sstevel@tonic-gate {
76*0Sstevel@tonic-gate 	register unsigned	incr;
77*0Sstevel@tonic-gate 
78*0Sstevel@tonic-gate 	incr = (unsigned)round(newtop - brkend + 1, BYTESPERWORD);
79*0Sstevel@tonic-gate 	if (brkincr > incr)
80*0Sstevel@tonic-gate 		incr = brkincr;
81*0Sstevel@tonic-gate 	if (setbrk(incr) == -1)
82*0Sstevel@tonic-gate 		error(nospace);
83*0Sstevel@tonic-gate }
84*0Sstevel@tonic-gate 
85*0Sstevel@tonic-gate unsigned char *
86*0Sstevel@tonic-gate savstak()
87*0Sstevel@tonic-gate {
88*0Sstevel@tonic-gate 	assert(staktop == stakbot);
89*0Sstevel@tonic-gate 	return(stakbot);
90*0Sstevel@tonic-gate }
91*0Sstevel@tonic-gate 
92*0Sstevel@tonic-gate unsigned char *
93*0Sstevel@tonic-gate endstak(argp)		/* tidy up after `locstak' */
94*0Sstevel@tonic-gate register unsigned char	*argp;
95*0Sstevel@tonic-gate {
96*0Sstevel@tonic-gate 	register unsigned char	*oldstak;
97*0Sstevel@tonic-gate 
98*0Sstevel@tonic-gate 	if (argp >= brkend)
99*0Sstevel@tonic-gate 		growstak(argp);
100*0Sstevel@tonic-gate 	*argp++ = 0;
101*0Sstevel@tonic-gate 	oldstak = stakbot;
102*0Sstevel@tonic-gate 	stakbot = staktop = (unsigned char *)round(argp, BYTESPERWORD);
103*0Sstevel@tonic-gate 	if (staktop >= brkend)
104*0Sstevel@tonic-gate 		growstak(staktop);
105*0Sstevel@tonic-gate 	return(oldstak);
106*0Sstevel@tonic-gate }
107*0Sstevel@tonic-gate 
108*0Sstevel@tonic-gate tdystak(x)		/* try to bring stack back to x */
109*0Sstevel@tonic-gate register unsigned char	*x;
110*0Sstevel@tonic-gate {
111*0Sstevel@tonic-gate 	while ((unsigned char *)stakbsy > x)
112*0Sstevel@tonic-gate 	{
113*0Sstevel@tonic-gate 		free(stakbsy);
114*0Sstevel@tonic-gate 		stakbsy = stakbsy->word;
115*0Sstevel@tonic-gate 	}
116*0Sstevel@tonic-gate 	staktop = stakbot = max(x, stakbas);
117*0Sstevel@tonic-gate 	rmtemp(x);
118*0Sstevel@tonic-gate }
119*0Sstevel@tonic-gate 
120*0Sstevel@tonic-gate stakchk()
121*0Sstevel@tonic-gate {
122*0Sstevel@tonic-gate 	if ((brkend - stakbas) > BRKINCR + BRKINCR)
123*0Sstevel@tonic-gate 		setbrk(-BRKINCR);
124*0Sstevel@tonic-gate }
125*0Sstevel@tonic-gate 
126*0Sstevel@tonic-gate unsigned char *
127*0Sstevel@tonic-gate cpystak(x)
128*0Sstevel@tonic-gate unsigned char	*x;
129*0Sstevel@tonic-gate {
130*0Sstevel@tonic-gate 	return(endstak(movstrstak(x, locstak())));
131*0Sstevel@tonic-gate }
132*0Sstevel@tonic-gate 
133*0Sstevel@tonic-gate unsigned char *
134*0Sstevel@tonic-gate movstrstak(a, b)
135*0Sstevel@tonic-gate register unsigned char	*a, *b;
136*0Sstevel@tonic-gate {
137*0Sstevel@tonic-gate 	do
138*0Sstevel@tonic-gate 	{
139*0Sstevel@tonic-gate 		if (b >= brkend)
140*0Sstevel@tonic-gate 			growstak(b);
141*0Sstevel@tonic-gate 	}
142*0Sstevel@tonic-gate 	while (*b++ = *a++);
143*0Sstevel@tonic-gate 	return(--b);
144*0Sstevel@tonic-gate }
145*0Sstevel@tonic-gate 
146*0Sstevel@tonic-gate /*
147*0Sstevel@tonic-gate  * Copy s2 to s1, always copy n bytes.
148*0Sstevel@tonic-gate  * Return s1
149*0Sstevel@tonic-gate  */
150*0Sstevel@tonic-gate unsigned char *
151*0Sstevel@tonic-gate memcpystak(s1, s2, n)
152*0Sstevel@tonic-gate register unsigned char *s1, *s2;
153*0Sstevel@tonic-gate register int n;
154*0Sstevel@tonic-gate {
155*0Sstevel@tonic-gate 	register unsigned char *os1 = s1;
156*0Sstevel@tonic-gate 
157*0Sstevel@tonic-gate 	while (--n >= 0) {
158*0Sstevel@tonic-gate 		if (s1 >= brkend)
159*0Sstevel@tonic-gate 			growstak(s1);
160*0Sstevel@tonic-gate 		*s1++ = *s2++;
161*0Sstevel@tonic-gate 	}
162*0Sstevel@tonic-gate 	return (os1);
163*0Sstevel@tonic-gate }
164