memalloc.c revision 1.23
1/* $NetBSD: memalloc.c,v 1.23 2000/11/01 19:56:01 christos Exp $ */ 2 3/*- 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Kenneth Almquist. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39#include <sys/cdefs.h> 40#ifndef lint 41#if 0 42static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95"; 43#else 44__RCSID("$NetBSD: memalloc.c,v 1.23 2000/11/01 19:56:01 christos Exp $"); 45#endif 46#endif /* not lint */ 47 48#include <stdlib.h> 49#include <unistd.h> 50 51#include "shell.h" 52#include "output.h" 53#include "memalloc.h" 54#include "error.h" 55#include "machdep.h" 56#include "mystring.h" 57 58/* 59 * Like malloc, but returns an error when out of space. 60 */ 61 62pointer 63ckmalloc(nbytes) 64 int nbytes; 65{ 66 pointer p; 67 68 INTOFF; 69 p = malloc(nbytes); 70 INTON; 71 if (p == NULL) 72 error("Out of space"); 73 return p; 74} 75 76 77/* 78 * Same for realloc. 79 */ 80 81pointer 82ckrealloc(p, nbytes) 83 pointer p; 84 int nbytes; 85{ 86 87 if ((p = realloc(p, nbytes)) == NULL) 88 error("Out of space"); 89 return p; 90} 91 92 93/* 94 * Make a copy of a string in safe storage. 95 */ 96 97char * 98savestr(s) 99 char *s; 100 { 101 char *p; 102 103 p = ckmalloc(strlen(s) + 1); 104 scopy(s, p); 105 return p; 106} 107 108 109/* 110 * Parse trees for commands are allocated in lifo order, so we use a stack 111 * to make this more efficient, and also to avoid all sorts of exception 112 * handling code to handle interrupts in the middle of a parse. 113 * 114 * The size 504 was chosen because the Ultrix malloc handles that size 115 * well. 116 */ 117 118#define MINSIZE 504 /* minimum size of a block */ 119 120 121struct stack_block { 122 struct stack_block *prev; 123 char space[MINSIZE]; 124}; 125 126struct stack_block stackbase; 127struct stack_block *stackp = &stackbase; 128struct stackmark *markp; 129char *stacknxt = stackbase.space; 130int stacknleft = MINSIZE; 131int sstrnleft; 132int herefd = -1; 133 134 135 136pointer 137stalloc(nbytes) 138 int nbytes; 139{ 140 char *p; 141 142 nbytes = ALIGN(nbytes); 143 if (nbytes > stacknleft) { 144 int blocksize; 145 struct stack_block *sp; 146 147 blocksize = nbytes; 148 if (blocksize < MINSIZE) 149 blocksize = MINSIZE; 150 INTOFF; 151 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize); 152 sp->prev = stackp; 153 stacknxt = sp->space; 154 stacknleft = blocksize; 155 stackp = sp; 156 INTON; 157 } 158 p = stacknxt; 159 stacknxt += nbytes; 160 stacknleft -= nbytes; 161 return p; 162} 163 164 165void 166stunalloc(p) 167 pointer p; 168 { 169 if (p == NULL) { /*DEBUG */ 170 write(2, "stunalloc\n", 10); 171 abort(); 172 } 173 stacknleft += stacknxt - (char *)p; 174 stacknxt = p; 175} 176 177 178 179void 180setstackmark(mark) 181 struct stackmark *mark; 182 { 183 mark->stackp = stackp; 184 mark->stacknxt = stacknxt; 185 mark->stacknleft = stacknleft; 186 mark->marknext = markp; 187 markp = mark; 188} 189 190 191void 192popstackmark(mark) 193 struct stackmark *mark; 194 { 195 struct stack_block *sp; 196 197 INTOFF; 198 markp = mark->marknext; 199 while (stackp != mark->stackp) { 200 sp = stackp; 201 stackp = sp->prev; 202 ckfree(sp); 203 } 204 stacknxt = mark->stacknxt; 205 stacknleft = mark->stacknleft; 206 INTON; 207} 208 209 210/* 211 * When the parser reads in a string, it wants to stick the string on the 212 * stack and only adjust the stack pointer when it knows how big the 213 * string is. Stackblock (defined in stack.h) returns a pointer to a block 214 * of space on top of the stack and stackblocklen returns the length of 215 * this block. Growstackblock will grow this space by at least one byte, 216 * possibly moving it (like realloc). Grabstackblock actually allocates the 217 * part of the block that has been used. 218 */ 219 220void 221growstackblock() { 222 char *p; 223 int newlen = ALIGN(stacknleft * 2 + 100); 224 char *oldspace = stacknxt; 225 int oldlen = stacknleft; 226 struct stack_block *sp; 227 struct stack_block *oldstackp; 228 229 if (stacknxt == stackp->space && stackp != &stackbase) { 230 INTOFF; 231 oldstackp = stackp; 232 sp = stackp; 233 stackp = sp->prev; 234 sp = ckrealloc((pointer)sp, sizeof(struct stack_block) - MINSIZE + newlen); 235 sp->prev = stackp; 236 stackp = sp; 237 stacknxt = sp->space; 238 stacknleft = newlen; 239 { 240 /* Stack marks pointing to the start of the old block 241 * must be relocated to point to the new block 242 */ 243 struct stackmark *xmark; 244 xmark = markp; 245 while (xmark != NULL && xmark->stackp == oldstackp) { 246 xmark->stackp = stackp; 247 xmark->stacknxt = stacknxt; 248 xmark->stacknleft = stacknleft; 249 xmark = xmark->marknext; 250 } 251 } 252 INTON; 253 } else { 254 p = stalloc(newlen); 255 memcpy(p, oldspace, oldlen); 256 stacknxt = p; /* free the space */ 257 stacknleft += newlen; /* we just allocated */ 258 } 259} 260 261 262 263void 264grabstackblock(len) 265 int len; 266{ 267 len = ALIGN(len); 268 stacknxt += len; 269 stacknleft -= len; 270} 271 272 273 274/* 275 * The following routines are somewhat easier to use that the above. 276 * The user declares a variable of type STACKSTR, which may be declared 277 * to be a register. The macro STARTSTACKSTR initializes things. Then 278 * the user uses the macro STPUTC to add characters to the string. In 279 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 280 * grown as necessary. When the user is done, she can just leave the 281 * string there and refer to it using stackblock(). Or she can allocate 282 * the space for it using grabstackstr(). If it is necessary to allow 283 * someone else to use the stack temporarily and then continue to grow 284 * the string, the user should use grabstack to allocate the space, and 285 * then call ungrabstr(p) to return to the previous mode of operation. 286 * 287 * USTPUTC is like STPUTC except that it doesn't check for overflow. 288 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 289 * is space for at least one character. 290 */ 291 292 293char * 294growstackstr() { 295 int len = stackblocksize(); 296 if (herefd >= 0 && len >= 1024) { 297 xwrite(herefd, stackblock(), len); 298 sstrnleft = len - 1; 299 return stackblock(); 300 } 301 growstackblock(); 302 sstrnleft = stackblocksize() - len - 1; 303 return stackblock() + len; 304} 305 306 307/* 308 * Called from CHECKSTRSPACE. 309 */ 310 311char * 312makestrspace() { 313 int len = stackblocksize() - sstrnleft; 314 growstackblock(); 315 sstrnleft = stackblocksize() - len; 316 return stackblock() + len; 317} 318 319 320 321void 322ungrabstackstr(s, p) 323 char *s; 324 char *p; 325 { 326 stacknleft += stacknxt - s; 327 stacknxt = s; 328 sstrnleft = stacknleft - (p - s); 329} 330