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 * 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 * 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 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 * 84 savstak() 85 { 86 assert(staktop == stakbot); 87 return(stakbot); 88 } 89 90 unsigned char * 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 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 121 stakchk(void) 122 { 123 if ((brkend - stakbas) > BRKINCR + BRKINCR) 124 setbrk(-BRKINCR); 125 } 126 127 unsigned char * 128 cpystak(x) 129 unsigned char *x; 130 { 131 return(endstak(movstrstak(x, locstak()))); 132 } 133 134 unsigned char * 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 * 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