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