memalloc.c revision 1.20
1 /* $NetBSD: memalloc.c,v 1.20 1997/07/04 21:02:08 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 42 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95"; 43 #else 44 __RCSID("$NetBSD: memalloc.c,v 1.20 1997/07/04 21:02:08 christos Exp $"); 45 #endif 46 #endif /* not lint */ 47 48 #include "shell.h" 49 #include "output.h" 50 #include "memalloc.h" 51 #include "error.h" 52 #include "machdep.h" 53 #include "mystring.h" 54 #include <stdlib.h> 55 #include <unistd.h> 56 57 /* 58 * Like malloc, but returns an error when out of space. 59 */ 60 61 pointer 62 ckmalloc(nbytes) 63 int nbytes; 64 { 65 pointer p; 66 67 if ((p = malloc(nbytes)) == NULL) 68 error("Out of space"); 69 return p; 70 } 71 72 73 /* 74 * Same for realloc. 75 */ 76 77 pointer 78 ckrealloc(p, nbytes) 79 pointer p; 80 int nbytes; 81 { 82 83 if ((p = realloc(p, nbytes)) == NULL) 84 error("Out of space"); 85 return p; 86 } 87 88 89 /* 90 * Make a copy of a string in safe storage. 91 */ 92 93 char * 94 savestr(s) 95 char *s; 96 { 97 char *p; 98 99 p = ckmalloc(strlen(s) + 1); 100 scopy(s, p); 101 return p; 102 } 103 104 105 /* 106 * Parse trees for commands are allocated in lifo order, so we use a stack 107 * to make this more efficient, and also to avoid all sorts of exception 108 * handling code to handle interrupts in the middle of a parse. 109 * 110 * The size 504 was chosen because the Ultrix malloc handles that size 111 * well. 112 */ 113 114 #define MINSIZE 504 /* minimum size of a block */ 115 116 117 struct stack_block { 118 struct stack_block *prev; 119 char space[MINSIZE]; 120 }; 121 122 struct stack_block stackbase; 123 struct stack_block *stackp = &stackbase; 124 char *stacknxt = stackbase.space; 125 int stacknleft = MINSIZE; 126 int sstrnleft; 127 int herefd = -1; 128 129 130 131 pointer 132 stalloc(nbytes) 133 int nbytes; 134 { 135 char *p; 136 137 nbytes = ALIGN(nbytes); 138 if (nbytes > stacknleft) { 139 int blocksize; 140 struct stack_block *sp; 141 142 blocksize = nbytes; 143 if (blocksize < MINSIZE) 144 blocksize = MINSIZE; 145 INTOFF; 146 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize); 147 sp->prev = stackp; 148 stacknxt = sp->space; 149 stacknleft = blocksize; 150 stackp = sp; 151 INTON; 152 } 153 p = stacknxt; 154 stacknxt += nbytes; 155 stacknleft -= nbytes; 156 return p; 157 } 158 159 160 void 161 stunalloc(p) 162 pointer p; 163 { 164 if (p == NULL) { /*DEBUG */ 165 write(2, "stunalloc\n", 10); 166 abort(); 167 } 168 stacknleft += stacknxt - (char *)p; 169 stacknxt = p; 170 } 171 172 173 174 void 175 setstackmark(mark) 176 struct stackmark *mark; 177 { 178 mark->stackp = stackp; 179 mark->stacknxt = stacknxt; 180 mark->stacknleft = stacknleft; 181 } 182 183 184 void 185 popstackmark(mark) 186 struct stackmark *mark; 187 { 188 struct stack_block *sp; 189 190 INTOFF; 191 while (stackp != mark->stackp) { 192 sp = stackp; 193 stackp = sp->prev; 194 ckfree(sp); 195 } 196 stacknxt = mark->stacknxt; 197 stacknleft = mark->stacknleft; 198 INTON; 199 } 200 201 202 /* 203 * When the parser reads in a string, it wants to stick the string on the 204 * stack and only adjust the stack pointer when it knows how big the 205 * string is. Stackblock (defined in stack.h) returns a pointer to a block 206 * of space on top of the stack and stackblocklen returns the length of 207 * this block. Growstackblock will grow this space by at least one byte, 208 * possibly moving it (like realloc). Grabstackblock actually allocates the 209 * part of the block that has been used. 210 */ 211 212 void 213 growstackblock() { 214 char *p; 215 int newlen = ALIGN(stacknleft * 2 + 100); 216 char *oldspace = stacknxt; 217 int oldlen = stacknleft; 218 struct stack_block *sp; 219 220 if (stacknxt == stackp->space && stackp != &stackbase) { 221 INTOFF; 222 sp = stackp; 223 stackp = sp->prev; 224 sp = ckrealloc((pointer)sp, sizeof(struct stack_block) - MINSIZE + newlen); 225 sp->prev = stackp; 226 stackp = sp; 227 stacknxt = sp->space; 228 stacknleft = newlen; 229 INTON; 230 } else { 231 p = stalloc(newlen); 232 memcpy(p, oldspace, oldlen); 233 stacknxt = p; /* free the space */ 234 stacknleft += newlen; /* we just allocated */ 235 } 236 } 237 238 239 240 void 241 grabstackblock(len) 242 int len; 243 { 244 len = ALIGN(len); 245 stacknxt += len; 246 stacknleft -= len; 247 } 248 249 250 251 /* 252 * The following routines are somewhat easier to use that the above. 253 * The user declares a variable of type STACKSTR, which may be declared 254 * to be a register. The macro STARTSTACKSTR initializes things. Then 255 * the user uses the macro STPUTC to add characters to the string. In 256 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 257 * grown as necessary. When the user is done, she can just leave the 258 * string there and refer to it using stackblock(). Or she can allocate 259 * the space for it using grabstackstr(). If it is necessary to allow 260 * someone else to use the stack temporarily and then continue to grow 261 * the string, the user should use grabstack to allocate the space, and 262 * then call ungrabstr(p) to return to the previous mode of operation. 263 * 264 * USTPUTC is like STPUTC except that it doesn't check for overflow. 265 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 266 * is space for at least one character. 267 */ 268 269 270 char * 271 growstackstr() { 272 int len = stackblocksize(); 273 if (herefd >= 0 && len >= 1024) { 274 xwrite(herefd, stackblock(), len); 275 sstrnleft = len - 1; 276 return stackblock(); 277 } 278 growstackblock(); 279 sstrnleft = stackblocksize() - len - 1; 280 return stackblock() + len; 281 } 282 283 284 /* 285 * Called from CHECKSTRSPACE. 286 */ 287 288 char * 289 makestrspace() { 290 int len = stackblocksize() - sstrnleft; 291 growstackblock(); 292 sstrnleft = stackblocksize() - len; 293 return stackblock() + len; 294 } 295 296 297 298 void 299 ungrabstackstr(s, p) 300 char *s; 301 char *p; 302 { 303 stacknleft += stacknxt - s; 304 stacknxt = s; 305 sstrnleft = stacknleft - (p - s); 306 } 307
Indexes created Tue Sep 23 07:09:52 GMT 2025