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 #if 0 39 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95"; 40 #endif 41 static const char rcsid[] = 42 "$Id$"; 43 #endif /* not lint */ 44 45 #include "shell.h" 46 #include "output.h" 47 #include "memalloc.h" 48 #include "error.h" 49 #include "machdep.h" 50 #include "mystring.h" 51 #include <stdlib.h> 52 #include <unistd.h> 53 54 /* 55 * Like malloc, but returns an error when out of space. 56 */ 57 58 pointer 59 ckmalloc(nbytes) 60 int nbytes; 61 { 62 pointer p; 63 64 if ((p = malloc(nbytes)) == NULL) 65 error("Out of space"); 66 return p; 67 } 68 69 70 /* 71 * Same for realloc. 72 */ 73 74 pointer 75 ckrealloc(p, nbytes) 76 pointer p; 77 int nbytes; 78 { 79 80 if ((p = realloc(p, nbytes)) == NULL) 81 error("Out of space"); 82 return p; 83 } 84 85 86 /* 87 * Make a copy of a string in safe storage. 88 */ 89 90 char * 91 savestr(s) 92 char *s; 93 { 94 char *p; 95 96 p = ckmalloc(strlen(s) + 1); 97 scopy(s, p); 98 return p; 99 } 100 101 102 /* 103 * Parse trees for commands are allocated in lifo order, so we use a stack 104 * to make this more efficient, and also to avoid all sorts of exception 105 * handling code to handle interrupts in the middle of a parse. 106 * 107 * The size 504 was chosen because the Ultrix malloc handles that size 108 * well. 109 */ 110 111 #define MINSIZE 504 /* minimum size of a block */ 112 113 114 struct stack_block { 115 struct stack_block *prev; 116 char space[MINSIZE]; 117 }; 118 119 struct stack_block stackbase; 120 struct stack_block *stackp = &stackbase; 121 char *stacknxt = stackbase.space; 122 int stacknleft = MINSIZE; 123 int sstrnleft; 124 int herefd = -1; 125 126 127 128 pointer 129 stalloc(nbytes) 130 int nbytes; 131 { 132 char *p; 133 134 nbytes = ALIGN(nbytes); 135 if (nbytes > stacknleft) { 136 int blocksize; 137 struct stack_block *sp; 138 139 blocksize = nbytes; 140 if (blocksize < MINSIZE) 141 blocksize = MINSIZE; 142 INTOFF; 143 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize); 144 sp->prev = stackp; 145 stacknxt = sp->space; 146 stacknleft = blocksize; 147 stackp = sp; 148 INTON; 149 } 150 p = stacknxt; 151 stacknxt += nbytes; 152 stacknleft -= nbytes; 153 return p; 154 } 155 156 157 void 158 stunalloc(p) 159 pointer p; 160 { 161 if (p == NULL) { /*DEBUG */ 162 write(2, "stunalloc\n", 10); 163 abort(); 164 } 165 stacknleft += stacknxt - (char *)p; 166 stacknxt = p; 167 } 168 169 170 171 void 172 setstackmark(mark) 173 struct stackmark *mark; 174 { 175 mark->stackp = stackp; 176 mark->stacknxt = stacknxt; 177 mark->stacknleft = stacknleft; 178 } 179 180 181 void 182 popstackmark(mark) 183 struct stackmark *mark; 184 { 185 struct stack_block *sp; 186 187 INTOFF; 188 while (stackp != mark->stackp) { 189 sp = stackp; 190 stackp = sp->prev; 191 ckfree(sp); 192 } 193 stacknxt = mark->stacknxt; 194 stacknleft = mark->stacknleft; 195 INTON; 196 } 197 198 199 /* 200 * When the parser reads in a string, it wants to stick the string on the 201 * stack and only adjust the stack pointer when it knows how big the 202 * string is. Stackblock (defined in stack.h) returns a pointer to a block 203 * of space on top of the stack and stackblocklen returns the length of 204 * this block. Growstackblock will grow this space by at least one byte, 205 * possibly moving it (like realloc). Grabstackblock actually allocates the 206 * part of the block that has been used. 207 */ 208 209 void 210 growstackblock() { 211 char *p; 212 int newlen = ALIGN(stacknleft * 2 + 100); 213 char *oldspace = stacknxt; 214 int oldlen = stacknleft; 215 struct stack_block *sp; 216 217 if (stacknxt == stackp->space && stackp != &stackbase) { 218 INTOFF; 219 sp = stackp; 220 stackp = sp->prev; 221 sp = ckrealloc((pointer)sp, sizeof(struct stack_block) - MINSIZE + newlen); 222 sp->prev = stackp; 223 stackp = sp; 224 stacknxt = sp->space; 225 stacknleft = newlen; 226 INTON; 227 } else { 228 p = stalloc(newlen); 229 memcpy(p, oldspace, oldlen); 230 stacknxt = p; /* free the space */ 231 stacknleft += newlen; /* we just allocated */ 232 } 233 } 234 235 236 237 void 238 grabstackblock(len) 239 int len; 240 { 241 len = ALIGN(len); 242 stacknxt += len; 243 stacknleft -= len; 244 } 245 246 247 248 /* 249 * The following routines are somewhat easier to use that the above. 250 * The user declares a variable of type STACKSTR, which may be declared 251 * to be a register. The macro STARTSTACKSTR initializes things. Then 252 * the user uses the macro STPUTC to add characters to the string. In 253 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 254 * grown as necessary. When the user is done, she can just leave the 255 * string there and refer to it using stackblock(). Or she can allocate 256 * the space for it using grabstackstr(). If it is necessary to allow 257 * someone else to use the stack temporarily and then continue to grow 258 * the string, the user should use grabstack to allocate the space, and 259 * then call ungrabstr(p) to return to the previous mode of operation. 260 * 261 * USTPUTC is like STPUTC except that it doesn't check for overflow. 262 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 263 * is space for at least one character. 264 */ 265 266 267 char * 268 growstackstr() { 269 int len = stackblocksize(); 270 if (herefd >= 0 && len >= 1024) { 271 xwrite(herefd, stackblock(), len); 272 sstrnleft = len - 1; 273 return stackblock(); 274 } 275 growstackblock(); 276 sstrnleft = stackblocksize() - len - 1; 277 return stackblock() + len; 278 } 279 280 281 /* 282 * Called from CHECKSTRSPACE. 283 */ 284 285 char * 286 makestrspace() { 287 int len = stackblocksize() - sstrnleft; 288 growstackblock(); 289 sstrnleft = stackblocksize() - len; 290 return stackblock() + len; 291 } 292 293 294 295 void 296 ungrabstackstr(s, p) 297 char *s; 298 char *p; 299 { 300 stacknleft += stacknxt - s; 301 stacknxt = s; 302 sstrnleft = stacknleft - (p - s); 303 } 304