1 /* $NetBSD: memalloc.c,v 1.25 2002/10/07 14:26:49 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 1.25 2002/10/07 14:26:49 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 p = malloc(nbytes); 69 if (p == NULL) 70 error("Out of space"); 71 return p; 72 } 73 74 75 /* 76 * Same for realloc. 77 */ 78 79 pointer 80 ckrealloc(p, nbytes) 81 pointer p; 82 int nbytes; 83 { 84 p = realloc(p, nbytes); 85 if (p == NULL) 86 error("Out of space"); 87 return p; 88 } 89 90 91 /* 92 * Make a copy of a string in safe storage. 93 */ 94 95 char * 96 savestr(s) 97 char *s; 98 { 99 char *p; 100 101 p = ckmalloc(strlen(s) + 1); 102 scopy(s, p); 103 return p; 104 } 105 106 107 /* 108 * Parse trees for commands are allocated in lifo order, so we use a stack 109 * to make this more efficient, and also to avoid all sorts of exception 110 * handling code to handle interrupts in the middle of a parse. 111 * 112 * The size 504 was chosen because the Ultrix malloc handles that size 113 * well. 114 */ 115 116 #define MINSIZE 504 /* minimum size of a block */ 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 struct stackmark *markp; 126 char *stacknxt = stackbase.space; 127 int stacknleft = MINSIZE; 128 int sstrnleft; 129 int herefd = -1; 130 131 pointer 132 stalloc(nbytes) 133 int nbytes; 134 { 135 char *p; 136 137 nbytes = SHELL_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 mark->marknext = markp; 182 markp = mark; 183 } 184 185 186 void 187 popstackmark(mark) 188 struct stackmark *mark; 189 { 190 struct stack_block *sp; 191 192 INTOFF; 193 markp = mark->marknext; 194 while (stackp != mark->stackp) { 195 sp = stackp; 196 stackp = sp->prev; 197 ckfree(sp); 198 } 199 stacknxt = mark->stacknxt; 200 stacknleft = mark->stacknleft; 201 INTON; 202 } 203 204 205 /* 206 * When the parser reads in a string, it wants to stick the string on the 207 * stack and only adjust the stack pointer when it knows how big the 208 * string is. Stackblock (defined in stack.h) returns a pointer to a block 209 * of space on top of the stack and stackblocklen returns the length of 210 * this block. Growstackblock will grow this space by at least one byte, 211 * possibly moving it (like realloc). Grabstackblock actually allocates the 212 * part of the block that has been used. 213 */ 214 215 void 216 growstackblock() 217 { 218 int newlen = SHELL_ALIGN(stacknleft * 2 + 100); 219 220 if (stacknxt == stackp->space && stackp != &stackbase) { 221 struct stack_block *oldstackp; 222 struct stackmark *xmark; 223 struct stack_block *sp; 224 225 INTOFF; 226 oldstackp = stackp; 227 sp = stackp; 228 stackp = sp->prev; 229 sp = ckrealloc((pointer)sp, 230 sizeof(struct stack_block) - MINSIZE + newlen); 231 sp->prev = stackp; 232 stackp = sp; 233 stacknxt = sp->space; 234 stacknleft = newlen; 235 236 /* 237 * Stack marks pointing to the start of the old block 238 * must be relocated to point to the new block 239 */ 240 xmark = markp; 241 while (xmark != NULL && xmark->stackp == oldstackp) { 242 xmark->stackp = stackp; 243 xmark->stacknxt = stacknxt; 244 xmark->stacknleft = stacknleft; 245 xmark = xmark->marknext; 246 } 247 INTON; 248 } else { 249 char *oldspace = stacknxt; 250 int oldlen = stacknleft; 251 char *p = stalloc(newlen); 252 253 (void)memcpy(p, oldspace, oldlen); 254 stacknxt = p; /* free the space */ 255 stacknleft += newlen; /* we just allocated */ 256 } 257 } 258 259 void 260 grabstackblock(len) 261 int len; 262 { 263 len = SHELL_ALIGN(len); 264 stacknxt += len; 265 stacknleft -= len; 266 } 267 268 /* 269 * The following routines are somewhat easier to use that the above. 270 * The user declares a variable of type STACKSTR, which may be declared 271 * to be a register. The macro STARTSTACKSTR initializes things. Then 272 * the user uses the macro STPUTC to add characters to the string. In 273 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 274 * grown as necessary. When the user is done, she can just leave the 275 * string there and refer to it using stackblock(). Or she can allocate 276 * the space for it using grabstackstr(). If it is necessary to allow 277 * someone else to use the stack temporarily and then continue to grow 278 * the string, the user should use grabstack to allocate the space, and 279 * then call ungrabstr(p) to return to the previous mode of operation. 280 * 281 * USTPUTC is like STPUTC except that it doesn't check for overflow. 282 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 283 * is space for at least one character. 284 */ 285 286 char * 287 growstackstr() 288 { 289 int len = stackblocksize(); 290 if (herefd >= 0 && len >= 1024) { 291 xwrite(herefd, stackblock(), len); 292 sstrnleft = len - 1; 293 return stackblock(); 294 } 295 growstackblock(); 296 sstrnleft = stackblocksize() - len - 1; 297 return stackblock() + len; 298 } 299 300 /* 301 * Called from CHECKSTRSPACE. 302 */ 303 304 char * 305 makestrspace() 306 { 307 int len = stackblocksize() - sstrnleft; 308 growstackblock(); 309 sstrnleft = stackblocksize() - len; 310 return stackblock() + len; 311 } 312 313 void 314 ungrabstackstr(s, p) 315 char *s; 316 char *p; 317 { 318 stacknleft += stacknxt - s; 319 stacknxt = s; 320 sstrnleft = stacknleft - (p - s); 321 322 } 323