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 * 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 * 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 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 * 85 savstak() 86 { 87 assert(staktop == stakbot); 88 return(stakbot); 89 } 90 91 unsigned char * 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 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 122 stakchk(void) 123 { 124 if ((brkend - stakbas) > BRKINCR + BRKINCR) 125 setbrk(-BRKINCR); 126 } 127 128 unsigned char * 129 cpystak(x) 130 unsigned char *x; 131 { 132 return(endstak(movstrstak(x, locstak()))); 133 } 134 135 unsigned char * 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 * 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