1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
27 /* All Rights Reserved */
28
29 #pragma ident "%Z%%M% %I% %E% SMI"
30 /*
31 * UNIX shell
32 */
33
34 #include "defs.h"
35
36
37 /* ======== storage allocation ======== */
38
39 unsigned char *
getstak(asize)40 getstak(asize) /* allocate requested stack */
41 int asize;
42 {
43 unsigned char *oldstak;
44 int size;
45
46 size = round(asize, BYTESPERWORD);
47 oldstak = stakbot;
48 staktop = stakbot += size;
49 if (staktop >= brkend)
50 growstak(staktop);
51 return(oldstak);
52 }
53
54 /*
55 * set up stack for local use
56 * should be followed by `endstak'
57 */
58 unsigned char *
locstak()59 locstak()
60 {
61 if (brkend - stakbot < BRKINCR)
62 {
63 if (setbrk(brkincr) == -1)
64 error(nostack);
65 if (brkincr < BRKMAX)
66 brkincr += 256;
67 }
68 return(stakbot);
69 }
70
71 void
growstak(newtop)72 growstak(newtop)
73 unsigned char *newtop;
74 {
75 unsigned incr;
76
77 incr = (unsigned)round(newtop - brkend + 1, BYTESPERWORD);
78 if (brkincr > incr)
79 incr = brkincr;
80 if (setbrk(incr) == -1)
81 error(nospace);
82 }
83
84 unsigned char *
savstak()85 savstak()
86 {
87 assert(staktop == stakbot);
88 return(stakbot);
89 }
90
91 unsigned char *
endstak(unsigned char * argp)92 endstak(unsigned char *argp) /* tidy up after `locstak' */
93 {
94 unsigned char *oldstak;
95
96 if (argp >= brkend)
97 growstak(argp);
98 *argp++ = 0;
99 oldstak = stakbot;
100 stakbot = staktop = (unsigned char *)round(argp, BYTESPERWORD);
101 if (staktop >= brkend)
102 growstak(staktop);
103 return(oldstak);
104 }
105
106 void
tdystak(unsigned char * x)107 tdystak(unsigned char *x) /* try to bring stack back to x */
108 {
109 struct blk *next;
110
111 while ((unsigned char *)stakbsy > x)
112 {
113 next = stakbsy->word;
114 free(stakbsy);
115 stakbsy = next;
116 }
117 staktop = stakbot = max(x, stakbas);
118 rmtemp(x);
119 }
120
121 void
stakchk(void)122 stakchk(void)
123 {
124 if ((brkend - stakbas) > BRKINCR + BRKINCR)
125 setbrk(-BRKINCR);
126 }
127
128 unsigned char *
cpystak(x)129 cpystak(x)
130 unsigned char *x;
131 {
132 return(endstak(movstrstak(x, locstak())));
133 }
134
135 unsigned char *
movstrstak(unsigned char * a,unsigned char * b)136 movstrstak(unsigned char *a, unsigned char *b)
137 {
138 do
139 {
140 if (b >= brkend)
141 growstak(b);
142 }
143 while (*b++ = *a++);
144 return(--b);
145 }
146
147 /*
148 * Copy s2 to s1, always copy n bytes.
149 * Return s1
150 */
151 unsigned char *
memcpystak(unsigned char * s1,unsigned char * s2,int n)152 memcpystak(unsigned char *s1, unsigned char *s2, int n)
153 {
154 unsigned char *os1 = s1;
155
156 while (--n >= 0) {
157 if (s1 >= brkend)
158 growstak(s1);
159 *s1++ = *s2++;
160 }
161 return (os1);
162 }
163