1 /* $NetBSD: memalloc.c,v 1.21 1998/01/31 12:36:17 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 1.21 1998/01/31 12:36:17 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 62 pointer 63 ckmalloc(nbytes) 64 int nbytes; 65 { 66 pointer p; 67 68 if ((p = malloc(nbytes)) == NULL) 69 error("Out of space"); 70 return p; 71 } 72 73 74 /* 75 * Same for realloc. 76 */ 77 78 pointer 79 ckrealloc(p, nbytes) 80 pointer p; 81 int nbytes; 82 { 83 84 if ((p = realloc(p, nbytes)) == NULL) 85 error("Out of space"); 86 return p; 87 } 88 89 90 /* 91 * Make a copy of a string in safe storage. 92 */ 93 94 char * 95 savestr(s) 96 char *s; 97 { 98 char *p; 99 100 p = ckmalloc(strlen(s) + 1); 101 scopy(s, p); 102 return p; 103 } 104 105 106 /* 107 * Parse trees for commands are allocated in lifo order, so we use a stack 108 * to make this more efficient, and also to avoid all sorts of exception 109 * handling code to handle interrupts in the middle of a parse. 110 * 111 * The size 504 was chosen because the Ultrix malloc handles that size 112 * well. 113 */ 114 115 #define MINSIZE 504 /* minimum size of a block */ 116 117 118 struct stack_block { 119 struct stack_block *prev; 120 char space[MINSIZE]; 121 }; 122 123 struct stack_block stackbase; 124 struct stack_block *stackp = &stackbase; 125 char *stacknxt = stackbase.space; 126 int stacknleft = MINSIZE; 127 int sstrnleft; 128 int herefd = -1; 129 130 131 132 pointer 133 stalloc(nbytes) 134 int nbytes; 135 { 136 char *p; 137 138 nbytes = ALIGN(nbytes); 139 if (nbytes > stacknleft) { 140 int blocksize; 141 struct stack_block *sp; 142 143 blocksize = nbytes; 144 if (blocksize < MINSIZE) 145 blocksize = MINSIZE; 146 INTOFF; 147 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize); 148 sp->prev = stackp; 149 stacknxt = sp->space; 150 stacknleft = blocksize; 151 stackp = sp; 152 INTON; 153 } 154 p = stacknxt; 155 stacknxt += nbytes; 156 stacknleft -= nbytes; 157 return p; 158 } 159 160 161 void 162 stunalloc(p) 163 pointer p; 164 { 165 if (p == NULL) { /*DEBUG */ 166 write(2, "stunalloc\n", 10); 167 abort(); 168 } 169 stacknleft += stacknxt - (char *)p; 170 stacknxt = p; 171 } 172 173 174 175 void 176 setstackmark(mark) 177 struct stackmark *mark; 178 { 179 mark->stackp = stackp; 180 mark->stacknxt = stacknxt; 181 mark->stacknleft = stacknleft; 182 } 183 184 185 void 186 popstackmark(mark) 187 struct stackmark *mark; 188 { 189 struct stack_block *sp; 190 191 INTOFF; 192 while (stackp != mark->stackp) { 193 sp = stackp; 194 stackp = sp->prev; 195 ckfree(sp); 196 } 197 stacknxt = mark->stacknxt; 198 stacknleft = mark->stacknleft; 199 INTON; 200 } 201 202 203 /* 204 * When the parser reads in a string, it wants to stick the string on the 205 * stack and only adjust the stack pointer when it knows how big the 206 * string is. Stackblock (defined in stack.h) returns a pointer to a block 207 * of space on top of the stack and stackblocklen returns the length of 208 * this block. Growstackblock will grow this space by at least one byte, 209 * possibly moving it (like realloc). Grabstackblock actually allocates the 210 * part of the block that has been used. 211 */ 212 213 void 214 growstackblock() { 215 char *p; 216 int newlen = ALIGN(stacknleft * 2 + 100); 217 char *oldspace = stacknxt; 218 int oldlen = stacknleft; 219 struct stack_block *sp; 220 221 if (stacknxt == stackp->space && stackp != &stackbase) { 222 INTOFF; 223 sp = stackp; 224 stackp = sp->prev; 225 sp = ckrealloc((pointer)sp, sizeof(struct stack_block) - MINSIZE + newlen); 226 sp->prev = stackp; 227 stackp = sp; 228 stacknxt = sp->space; 229 stacknleft = newlen; 230 INTON; 231 } else { 232 p = stalloc(newlen); 233 memcpy(p, oldspace, oldlen); 234 stacknxt = p; /* free the space */ 235 stacknleft += newlen; /* we just allocated */ 236 } 237 } 238 239 240 241 void 242 grabstackblock(len) 243 int len; 244 { 245 len = ALIGN(len); 246 stacknxt += len; 247 stacknleft -= len; 248 } 249 250 251 252 /* 253 * The following routines are somewhat easier to use that the above. 254 * The user declares a variable of type STACKSTR, which may be declared 255 * to be a register. The macro STARTSTACKSTR initializes things. Then 256 * the user uses the macro STPUTC to add characters to the string. In 257 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 258 * grown as necessary. When the user is done, she can just leave the 259 * string there and refer to it using stackblock(). Or she can allocate 260 * the space for it using grabstackstr(). If it is necessary to allow 261 * someone else to use the stack temporarily and then continue to grow 262 * the string, the user should use grabstack to allocate the space, and 263 * then call ungrabstr(p) to return to the previous mode of operation. 264 * 265 * USTPUTC is like STPUTC except that it doesn't check for overflow. 266 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 267 * is space for at least one character. 268 */ 269 270 271 char * 272 growstackstr() { 273 int len = stackblocksize(); 274 if (herefd >= 0 && len >= 1024) { 275 xwrite(herefd, stackblock(), len); 276 sstrnleft = len - 1; 277 return stackblock(); 278 } 279 growstackblock(); 280 sstrnleft = stackblocksize() - len - 1; 281 return stackblock() + len; 282 } 283 284 285 /* 286 * Called from CHECKSTRSPACE. 287 */ 288 289 char * 290 makestrspace() { 291 int len = stackblocksize() - sstrnleft; 292 growstackblock(); 293 sstrnleft = stackblocksize() - len; 294 return stackblock() + len; 295 } 296 297 298 299 void 300 ungrabstackstr(s, p) 301 char *s; 302 char *p; 303 { 304 stacknleft += stacknxt - s; 305 stacknxt = s; 306 sstrnleft = stacknleft - (p - s); 307 } 308