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 37 #ifndef lint 38 /*static char sccsid[] = "from: @(#)memalloc.c 8.1 (Berkeley) 5/31/93";*/ 39 static char *rcsid = "$Id: memalloc.c,v 1.10 1994/12/04 07:12:19 cgd Exp $"; 40 #endif /* not lint */ 41 42 #include "shell.h" 43 #include "output.h" 44 #include "memalloc.h" 45 #include "error.h" 46 #include "machdep.h" 47 #include "mystring.h" 48 #include <stdlib.h> 49 #include <unistd.h> 50 51 /* 52 * Like malloc, but returns an error when out of space. 53 */ 54 55 pointer 56 ckmalloc(nbytes) 57 int nbytes; 58 { 59 register pointer p; 60 61 if ((p = malloc(nbytes)) == NULL) 62 error("Out of space"); 63 return p; 64 } 65 66 67 /* 68 * Same for realloc. 69 */ 70 71 pointer 72 ckrealloc(p, nbytes) 73 register pointer p; 74 int nbytes; 75 { 76 77 if ((p = realloc(p, nbytes)) == NULL) 78 error("Out of space"); 79 return p; 80 } 81 82 83 /* 84 * Make a copy of a string in safe storage. 85 */ 86 87 char * 88 savestr(s) 89 char *s; 90 { 91 register char *p; 92 93 p = ckmalloc(strlen(s) + 1); 94 scopy(s, p); 95 return p; 96 } 97 98 99 /* 100 * Parse trees for commands are allocated in lifo order, so we use a stack 101 * to make this more efficient, and also to avoid all sorts of exception 102 * handling code to handle interrupts in the middle of a parse. 103 * 104 * The size 504 was chosen because the Ultrix malloc handles that size 105 * well. 106 */ 107 108 #define MINSIZE 504 /* minimum size of a block */ 109 110 111 struct stack_block { 112 struct stack_block *prev; 113 char space[MINSIZE]; 114 }; 115 116 struct stack_block stackbase; 117 struct stack_block *stackp = &stackbase; 118 char *stacknxt = stackbase.space; 119 int stacknleft = MINSIZE; 120 int sstrnleft; 121 int herefd = -1; 122 123 124 125 pointer 126 stalloc(nbytes) 127 int nbytes; 128 { 129 register char *p; 130 131 nbytes = ALIGN(nbytes); 132 if (nbytes > stacknleft) { 133 int blocksize; 134 struct stack_block *sp; 135 136 blocksize = nbytes; 137 if (blocksize < MINSIZE) 138 blocksize = MINSIZE; 139 INTOFF; 140 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize); 141 sp->prev = stackp; 142 stacknxt = sp->space; 143 stacknleft = blocksize; 144 stackp = sp; 145 INTON; 146 } 147 p = stacknxt; 148 stacknxt += nbytes; 149 stacknleft -= nbytes; 150 return p; 151 } 152 153 154 void 155 stunalloc(p) 156 pointer p; 157 { 158 if (p == NULL) { /*DEBUG */ 159 write(2, "stunalloc\n", 10); 160 abort(); 161 } 162 stacknleft += stacknxt - (char *)p; 163 stacknxt = p; 164 } 165 166 167 168 void 169 setstackmark(mark) 170 struct stackmark *mark; 171 { 172 mark->stackp = stackp; 173 mark->stacknxt = stacknxt; 174 mark->stacknleft = stacknleft; 175 } 176 177 178 void 179 popstackmark(mark) 180 struct stackmark *mark; 181 { 182 struct stack_block *sp; 183 184 INTOFF; 185 while (stackp != mark->stackp) { 186 sp = stackp; 187 stackp = sp->prev; 188 ckfree(sp); 189 } 190 stacknxt = mark->stacknxt; 191 stacknleft = mark->stacknleft; 192 INTON; 193 } 194 195 196 /* 197 * When the parser reads in a string, it wants to stick the string on the 198 * stack and only adjust the stack pointer when it knows how big the 199 * string is. Stackblock (defined in stack.h) returns a pointer to a block 200 * of space on top of the stack and stackblocklen returns the length of 201 * this block. Growstackblock will grow this space by at least one byte, 202 * possibly moving it (like realloc). Grabstackblock actually allocates the 203 * part of the block that has been used. 204 */ 205 206 void 207 growstackblock() { 208 char *p; 209 int newlen = stacknleft * 2 + 100; 210 char *oldspace = stacknxt; 211 int oldlen = stacknleft; 212 struct stack_block *sp; 213 214 if (stacknxt == stackp->space && stackp != &stackbase) { 215 INTOFF; 216 sp = stackp; 217 stackp = sp->prev; 218 sp = ckrealloc((pointer)sp, sizeof(struct stack_block) - MINSIZE + newlen); 219 sp->prev = stackp; 220 stackp = sp; 221 stacknxt = sp->space; 222 stacknleft = newlen; 223 INTON; 224 } else { 225 p = stalloc(newlen); 226 memcpy(p, oldspace, oldlen); 227 stacknxt = p; /* free the space */ 228 stacknleft += newlen; /* we just allocated */ 229 } 230 } 231 232 233 234 void 235 grabstackblock(len) 236 int len; 237 { 238 len = ALIGN(len); 239 stacknxt += len; 240 stacknleft -= len; 241 } 242 243 244 245 /* 246 * The following routines are somewhat easier to use that the above. 247 * The user declares a variable of type STACKSTR, which may be declared 248 * to be a register. The macro STARTSTACKSTR initializes things. Then 249 * the user uses the macro STPUTC to add characters to the string. In 250 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 251 * grown as necessary. When the user is done, she can just leave the 252 * string there and refer to it using stackblock(). Or she can allocate 253 * the space for it using grabstackstr(). If it is necessary to allow 254 * someone else to use the stack temporarily and then continue to grow 255 * the string, the user should use grabstack to allocate the space, and 256 * then call ungrabstr(p) to return to the previous mode of operation. 257 * 258 * USTPUTC is like STPUTC except that it doesn't check for overflow. 259 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 260 * is space for at least one character. 261 */ 262 263 264 char * 265 growstackstr() { 266 int len = stackblocksize(); 267 if (herefd >= 0 && len >= 1024) { 268 xwrite(herefd, stackblock(), len); 269 sstrnleft = len - 1; 270 return stackblock(); 271 } 272 growstackblock(); 273 sstrnleft = stackblocksize() - len - 1; 274 return stackblock() + len; 275 } 276 277 278 /* 279 * Called from CHECKSTRSPACE. 280 */ 281 282 char * 283 makestrspace() { 284 int len = stackblocksize() - sstrnleft; 285 growstackblock(); 286 sstrnleft = stackblocksize() - len; 287 return stackblock() + len; 288 } 289 290 291 292 void 293 ungrabstackstr(s, p) 294 char *s; 295 char *p; 296 { 297 stacknleft += stacknxt - s; 298 stacknxt = s; 299 sstrnleft = stacknleft - (p - s); 300 } 301