memalloc.c revision 18018
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 * $Id: memalloc.c,v 1.3 1996/09/01 10:20:42 peter Exp $ 37 */ 38 39#ifndef lint 40static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95"; 41#endif /* not lint */ 42 43#include "shell.h" 44#include "output.h" 45#include "memalloc.h" 46#include "error.h" 47#include "machdep.h" 48#include "mystring.h" 49#include <stdlib.h> 50#include <unistd.h> 51 52/* 53 * Like malloc, but returns an error when out of space. 54 */ 55 56pointer 57ckmalloc(nbytes) 58 int nbytes; 59{ 60 register pointer p; 61 62 if ((p = malloc(nbytes)) == NULL) 63 error("Out of space"); 64 return p; 65} 66 67 68/* 69 * Same for realloc. 70 */ 71 72pointer 73ckrealloc(p, nbytes) 74 register pointer p; 75 int nbytes; 76{ 77 78 if ((p = realloc(p, nbytes)) == NULL) 79 error("Out of space"); 80 return p; 81} 82 83 84/* 85 * Make a copy of a string in safe storage. 86 */ 87 88char * 89savestr(s) 90 char *s; 91 { 92 register char *p; 93 94 p = ckmalloc(strlen(s) + 1); 95 scopy(s, p); 96 return p; 97} 98 99 100/* 101 * Parse trees for commands are allocated in lifo order, so we use a stack 102 * to make this more efficient, and also to avoid all sorts of exception 103 * handling code to handle interrupts in the middle of a parse. 104 * 105 * The size 504 was chosen because the Ultrix malloc handles that size 106 * well. 107 */ 108 109#define MINSIZE 504 /* minimum size of a block */ 110 111 112struct stack_block { 113 struct stack_block *prev; 114 char space[MINSIZE]; 115}; 116 117struct stack_block stackbase; 118struct stack_block *stackp = &stackbase; 119char *stacknxt = stackbase.space; 120int stacknleft = MINSIZE; 121int sstrnleft; 122int herefd = -1; 123 124 125 126pointer 127stalloc(nbytes) 128 int nbytes; 129{ 130 register char *p; 131 132 nbytes = ALIGN(nbytes); 133 if (nbytes > stacknleft) { 134 int blocksize; 135 struct stack_block *sp; 136 137 blocksize = nbytes; 138 if (blocksize < MINSIZE) 139 blocksize = MINSIZE; 140 INTOFF; 141 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize); 142 sp->prev = stackp; 143 stacknxt = sp->space; 144 stacknleft = blocksize; 145 stackp = sp; 146 INTON; 147 } 148 p = stacknxt; 149 stacknxt += nbytes; 150 stacknleft -= nbytes; 151 return p; 152} 153 154 155void 156stunalloc(p) 157 pointer p; 158 { 159 if (p == NULL) { /*DEBUG */ 160 write(2, "stunalloc\n", 10); 161 abort(); 162 } 163 stacknleft += stacknxt - (char *)p; 164 stacknxt = p; 165} 166 167 168 169void 170setstackmark(mark) 171 struct stackmark *mark; 172 { 173 mark->stackp = stackp; 174 mark->stacknxt = stacknxt; 175 mark->stacknleft = stacknleft; 176} 177 178 179void 180popstackmark(mark) 181 struct stackmark *mark; 182 { 183 struct stack_block *sp; 184 185 INTOFF; 186 while (stackp != mark->stackp) { 187 sp = stackp; 188 stackp = sp->prev; 189 ckfree(sp); 190 } 191 stacknxt = mark->stacknxt; 192 stacknleft = mark->stacknleft; 193 INTON; 194} 195 196 197/* 198 * When the parser reads in a string, it wants to stick the string on the 199 * stack and only adjust the stack pointer when it knows how big the 200 * string is. Stackblock (defined in stack.h) returns a pointer to a block 201 * of space on top of the stack and stackblocklen returns the length of 202 * this block. Growstackblock will grow this space by at least one byte, 203 * possibly moving it (like realloc). Grabstackblock actually allocates the 204 * part of the block that has been used. 205 */ 206 207void 208growstackblock() { 209 char *p; 210 int newlen = ALIGN(stacknleft * 2 + 100); 211 char *oldspace = stacknxt; 212 int oldlen = stacknleft; 213 struct stack_block *sp; 214 215 if (stacknxt == stackp->space && stackp != &stackbase) { 216 INTOFF; 217 sp = stackp; 218 stackp = sp->prev; 219 sp = ckrealloc((pointer)sp, sizeof(struct stack_block) - MINSIZE + newlen); 220 sp->prev = stackp; 221 stackp = sp; 222 stacknxt = sp->space; 223 stacknleft = newlen; 224 INTON; 225 } else { 226 p = stalloc(newlen); 227 memcpy(p, oldspace, oldlen); 228 stacknxt = p; /* free the space */ 229 stacknleft += newlen; /* we just allocated */ 230 } 231} 232 233 234 235void 236grabstackblock(len) 237 int len; 238{ 239 len = ALIGN(len); 240 stacknxt += len; 241 stacknleft -= len; 242} 243 244 245 246/* 247 * The following routines are somewhat easier to use that the above. 248 * The user declares a variable of type STACKSTR, which may be declared 249 * to be a register. The macro STARTSTACKSTR initializes things. Then 250 * the user uses the macro STPUTC to add characters to the string. In 251 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 252 * grown as necessary. When the user is done, she can just leave the 253 * string there and refer to it using stackblock(). Or she can allocate 254 * the space for it using grabstackstr(). If it is necessary to allow 255 * someone else to use the stack temporarily and then continue to grow 256 * the string, the user should use grabstack to allocate the space, and 257 * then call ungrabstr(p) to return to the previous mode of operation. 258 * 259 * USTPUTC is like STPUTC except that it doesn't check for overflow. 260 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 261 * is space for at least one character. 262 */ 263 264 265char * 266growstackstr() { 267 int len = stackblocksize(); 268 if (herefd >= 0 && len >= 1024) { 269 xwrite(herefd, stackblock(), len); 270 sstrnleft = len - 1; 271 return stackblock(); 272 } 273 growstackblock(); 274 sstrnleft = stackblocksize() - len - 1; 275 return stackblock() + len; 276} 277 278 279/* 280 * Called from CHECKSTRSPACE. 281 */ 282 283char * 284makestrspace() { 285 int len = stackblocksize() - sstrnleft; 286 growstackblock(); 287 sstrnleft = stackblocksize() - len; 288 return stackblock() + len; 289} 290 291 292 293void 294ungrabstackstr(s, p) 295 char *s; 296 char *p; 297 { 298 stacknleft += stacknxt - s; 299 stacknxt = s; 300 sstrnleft = stacknleft - (p - s); 301} 302