memalloc.c revision 1.8
1/*- 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Kenneth Almquist. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37#ifndef lint 38/*static char sccsid[] = "from: @(#)memalloc.c 8.1 (Berkeley) 5/31/93";*/ 39static char *rcsid = "$Id: memalloc.c,v 1.8 1994/06/11 16:12:08 mycroft Exp $"; 40#endif /* not lint */ 41 42#include "shell.h" 43#include "output.h" 44#include "memalloc.h" 45#include "error.h" 46#include "machdep.h" 47#include "mystring.h" 48#include <stdlib.h> 49#include <unistd.h> 50 51/* 52 * Like malloc, but returns an error when out of space. 53 */ 54 55pointer 56ckmalloc(nbytes) { 57 register pointer p; 58 59 if ((p = malloc(nbytes)) == NULL) 60 error("Out of space"); 61 return p; 62} 63 64 65/* 66 * Same for realloc. 67 */ 68 69pointer 70ckrealloc(p, nbytes) 71 register pointer p; 72 { 73 74 if ((p = realloc(p, nbytes)) == NULL) 75 error("Out of space"); 76 return p; 77} 78 79 80/* 81 * Make a copy of a string in safe storage. 82 */ 83 84char * 85savestr(s) 86 char *s; 87 { 88 register char *p; 89 90 p = ckmalloc(strlen(s) + 1); 91 scopy(s, p); 92 return p; 93} 94 95 96/* 97 * Parse trees for commands are allocated in lifo order, so we use a stack 98 * to make this more efficient, and also to avoid all sorts of exception 99 * handling code to handle interrupts in the middle of a parse. 100 * 101 * The size 504 was chosen because the Ultrix malloc handles that size 102 * well. 103 */ 104 105#define MINSIZE 504 /* minimum size of a block */ 106 107 108struct stack_block { 109 struct stack_block *prev; 110 char space[MINSIZE]; 111}; 112 113struct stack_block stackbase; 114struct stack_block *stackp = &stackbase; 115char *stacknxt = stackbase.space; 116int stacknleft = MINSIZE; 117int sstrnleft; 118int herefd = -1; 119 120 121 122pointer 123stalloc(nbytes) { 124 register char *p; 125 126 nbytes = ALIGN(nbytes); 127 if (nbytes > stacknleft) { 128 int blocksize; 129 struct stack_block *sp; 130 131 blocksize = nbytes; 132 if (blocksize < MINSIZE) 133 blocksize = MINSIZE; 134 INTOFF; 135 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize); 136 sp->prev = stackp; 137 stacknxt = sp->space; 138 stacknleft = blocksize; 139 stackp = sp; 140 INTON; 141 } 142 p = stacknxt; 143 stacknxt += nbytes; 144 stacknleft -= nbytes; 145 return p; 146} 147 148 149void 150stunalloc(p) 151 pointer p; 152 { 153 if (p == NULL) { /*DEBUG */ 154 write(2, "stunalloc\n", 10); 155 abort(); 156 } 157 stacknleft += stacknxt - (char *)p; 158 stacknxt = p; 159} 160 161 162 163void 164setstackmark(mark) 165 struct stackmark *mark; 166 { 167 mark->stackp = stackp; 168 mark->stacknxt = stacknxt; 169 mark->stacknleft = stacknleft; 170} 171 172 173void 174popstackmark(mark) 175 struct stackmark *mark; 176 { 177 struct stack_block *sp; 178 179 INTOFF; 180 while (stackp != mark->stackp) { 181 sp = stackp; 182 stackp = sp->prev; 183 ckfree(sp); 184 } 185 stacknxt = mark->stacknxt; 186 stacknleft = mark->stacknleft; 187 INTON; 188} 189 190 191/* 192 * When the parser reads in a string, it wants to stick the string on the 193 * stack and only adjust the stack pointer when it knows how big the 194 * string is. Stackblock (defined in stack.h) returns a pointer to a block 195 * of space on top of the stack and stackblocklen returns the length of 196 * this block. Growstackblock will grow this space by at least one byte, 197 * possibly moving it (like realloc). Grabstackblock actually allocates the 198 * part of the block that has been used. 199 */ 200 201void 202growstackblock() { 203 char *p; 204 int newlen = stacknleft * 2 + 100; 205 char *oldspace = stacknxt; 206 int oldlen = stacknleft; 207 struct stack_block *sp; 208 209 if (stacknxt == stackp->space && stackp != &stackbase) { 210 INTOFF; 211 sp = stackp; 212 stackp = sp->prev; 213 sp = ckrealloc((pointer)sp, sizeof(struct stack_block) - MINSIZE + newlen); 214 sp->prev = stackp; 215 stackp = sp; 216 stacknxt = sp->space; 217 stacknleft = newlen; 218 INTON; 219 } else { 220 p = stalloc(newlen); 221 bcopy(oldspace, p, oldlen); 222 stacknxt = p; /* free the space */ 223 stacknleft += newlen; /* we just allocated */ 224 } 225} 226 227 228 229void 230grabstackblock(len) { 231 len = ALIGN(len); 232 stacknxt += len; 233 stacknleft -= len; 234} 235 236 237 238/* 239 * The following routines are somewhat easier to use that the above. 240 * The user declares a variable of type STACKSTR, which may be declared 241 * to be a register. The macro STARTSTACKSTR initializes things. Then 242 * the user uses the macro STPUTC to add characters to the string. In 243 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 244 * grown as necessary. When the user is done, she can just leave the 245 * string there and refer to it using stackblock(). Or she can allocate 246 * the space for it using grabstackstr(). If it is necessary to allow 247 * someone else to use the stack temporarily and then continue to grow 248 * the string, the user should use grabstack to allocate the space, and 249 * then call ungrabstr(p) to return to the previous mode of operation. 250 * 251 * USTPUTC is like STPUTC except that it doesn't check for overflow. 252 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 253 * is space for at least one character. 254 */ 255 256 257char * 258growstackstr() { 259 int len = stackblocksize(); 260 if (herefd >= 0 && len >= 1024) { 261 xwrite(herefd, stackblock(), len); 262 sstrnleft = len - 1; 263 return stackblock(); 264 } 265 growstackblock(); 266 sstrnleft = stackblocksize() - len - 1; 267 return stackblock() + len; 268} 269 270 271/* 272 * Called from CHECKSTRSPACE. 273 */ 274 275char * 276makestrspace() { 277 int len = stackblocksize() - sstrnleft; 278 growstackblock(); 279 sstrnleft = stackblocksize() - len; 280 return stackblock() + len; 281} 282 283 284 285void 286ungrabstackstr(s, p) 287 char *s; 288 char *p; 289 { 290 stacknleft += stacknxt - s; 291 stacknxt = s; 292 sstrnleft = stacknleft - (p - s); 293} 294