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 /*
30 * UNIX shell
31 */
32
33 #include "defs.h"
34
35
36 /* ======== storage allocation ======== */
37
38 unsigned char *
getstak(asize)39 getstak(asize) /* allocate requested stack */
40 int asize;
41 {
42 unsigned char *oldstak;
43 int size;
44
45 size = round(asize, BYTESPERWORD);
46 oldstak = stakbot;
47 staktop = stakbot += size;
48 if (staktop >= brkend)
49 growstak(staktop);
50 return(oldstak);
51 }
52
53 /*
54 * set up stack for local use
55 * should be followed by `endstak'
56 */
57 unsigned char *
locstak()58 locstak()
59 {
60 if (brkend - stakbot < BRKINCR)
61 {
62 if (setbrk(brkincr) == -1)
63 error(nostack);
64 if (brkincr < BRKMAX)
65 brkincr += 256;
66 }
67 return(stakbot);
68 }
69
70 void
growstak(newtop)71 growstak(newtop)
72 unsigned char *newtop;
73 {
74 unsigned incr;
75
76 incr = (unsigned)round(newtop - brkend + 1, BYTESPERWORD);
77 if (brkincr > incr)
78 incr = brkincr;
79 if (setbrk(incr) == -1)
80 error(nospace);
81 }
82
83 unsigned char *
savstak()84 savstak()
85 {
86 assert(staktop == stakbot);
87 return(stakbot);
88 }
89
90 unsigned char *
endstak(unsigned char * argp)91 endstak(unsigned char *argp) /* tidy up after `locstak' */
92 {
93 unsigned char *oldstak;
94
95 if (argp >= brkend)
96 growstak(argp);
97 *argp++ = 0;
98 oldstak = stakbot;
99 stakbot = staktop = (unsigned char *)round(argp, BYTESPERWORD);
100 if (staktop >= brkend)
101 growstak(staktop);
102 return(oldstak);
103 }
104
105 void
tdystak(unsigned char * x)106 tdystak(unsigned char *x) /* try to bring stack back to x */
107 {
108 struct blk *next;
109
110 while ((unsigned char *)stakbsy > x)
111 {
112 next = stakbsy->word;
113 free(stakbsy);
114 stakbsy = next;
115 }
116 staktop = stakbot = max(x, stakbas);
117 rmtemp(x);
118 }
119
120 void
stakchk(void)121 stakchk(void)
122 {
123 if ((brkend - stakbas) > BRKINCR + BRKINCR)
124 setbrk(-BRKINCR);
125 }
126
127 unsigned char *
cpystak(x)128 cpystak(x)
129 unsigned char *x;
130 {
131 return(endstak(movstrstak(x, locstak())));
132 }
133
134 unsigned char *
movstrstak(unsigned char * a,unsigned char * b)135 movstrstak(unsigned char *a, unsigned char *b)
136 {
137 do
138 {
139 if (b >= brkend)
140 growstak(b);
141 }
142 while (*b++ = *a++);
143 return(--b);
144 }
145
146 /*
147 * Copy s2 to s1, always copy n bytes.
148 * Return s1
149 */
150 unsigned char *
memcpystak(unsigned char * s1,unsigned char * s2,int n)151 memcpystak(unsigned char *s1, unsigned char *s2, int n)
152 {
153 unsigned char *os1 = s1;
154
155 while (--n >= 0) {
156 if (s1 >= brkend)
157 growstak(s1);
158 *s1++ = *s2++;
159 }
160 return (os1);
161 }
162