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 1.7 1997/02/22 13:58:34 peter Exp $ 37 */ 38 39 #ifndef lint 40 static char const 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 56 pointer 57 ckmalloc(nbytes) 58 int nbytes; 59 { 60 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 72 pointer 73 ckrealloc(p, nbytes) 74 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 88 char * 89 savestr(s) 90 char *s; 91 { 92 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 */ 110 111 112 struct stack_block { 113 struct stack_block *prev; 114 char space[MINSIZE]; 115 }; 116 117 struct stack_block stackbase; 118 struct stack_block *stackp = &stackbase; 119 char *stacknxt = stackbase.space; 120 int stacknleft = MINSIZE; 121 int sstrnleft; 122 int herefd = -1; 123 124 125 126 pointer 127 stalloc(nbytes) 128 int nbytes; 129 { 130 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 } 153 154 155 void 156 stunalloc(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 } 166 167 168 169 void 170 setstackmark(mark) 171 struct stackmark *mark; 172 { 173 mark->stackp = stackp; 174 mark->stacknxt = stacknxt; 175 mark->stacknleft = stacknleft; 176 } 177 178 179 void 180 popstackmark(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 */ 206 207 void 208 growstackblock() { 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 } 232 233 234 235 void 236 grabstackblock(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 */ 263 264 265 char * 266 growstackstr() { 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 */ 282 283 char * 284 makestrspace() { 285 int len = stackblocksize() - sstrnleft; 286 growstackblock(); 287 sstrnleft = stackblocksize() - len; 288 return stackblock() + len; 289 } 290 291 292 293 void 294 ungrabstackstr(s, p) 295 char *s; 296 char *p; 297 { 298 stacknleft += stacknxt - s; 299 stacknxt = s; 300 sstrnleft = stacknleft - (p - s); 301 } 302