1 /* $NetBSD: memalloc.c,v 1.27 2003/01/22 20:36:04 dsl 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 1.27 2003/01/22 20:36:04 dsl 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(int nbytes) 64 { 65 pointer p; 66 67 p = malloc(nbytes); 68 if (p == NULL) 69 error("Out of space"); 70 return p; 71 } 72 73 74 /* 75 * Same for realloc. 76 */ 77 78 pointer 79 ckrealloc(pointer p, int nbytes) 80 { 81 p = realloc(p, nbytes); 82 if (p == NULL) 83 error("Out of space"); 84 return p; 85 } 86 87 88 /* 89 * Make a copy of a string in safe storage. 90 */ 91 92 char * 93 savestr(const char *s) 94 { 95 char *p; 96 97 p = ckmalloc(strlen(s) + 1); 98 scopy(s, p); 99 return p; 100 } 101 102 103 /* 104 * Parse trees for commands are allocated in lifo order, so we use a stack 105 * to make this more efficient, and also to avoid all sorts of exception 106 * handling code to handle interrupts in the middle of a parse. 107 * 108 * The size 504 was chosen because the Ultrix malloc handles that size 109 * well. 110 */ 111 112 #define MINSIZE 504 /* minimum size of a block */ 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 struct stackmark *markp; 122 char *stacknxt = stackbase.space; 123 int stacknleft = MINSIZE; 124 int sstrnleft; 125 int herefd = -1; 126 127 pointer 128 stalloc(int nbytes) 129 { 130 char *p; 131 132 nbytes = SHELL_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(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(struct stackmark *mark) 170 { 171 mark->stackp = stackp; 172 mark->stacknxt = stacknxt; 173 mark->stacknleft = stacknleft; 174 mark->marknext = markp; 175 markp = mark; 176 } 177 178 179 void 180 popstackmark(struct stackmark *mark) 181 { 182 struct stack_block *sp; 183 184 INTOFF; 185 markp = mark->marknext; 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(void) 209 { 210 int newlen = SHELL_ALIGN(stacknleft * 2 + 100); 211 212 if (stacknxt == stackp->space && stackp != &stackbase) { 213 struct stack_block *oldstackp; 214 struct stackmark *xmark; 215 struct stack_block *sp; 216 217 INTOFF; 218 oldstackp = stackp; 219 sp = stackp; 220 stackp = sp->prev; 221 sp = ckrealloc((pointer)sp, 222 sizeof(struct stack_block) - MINSIZE + newlen); 223 sp->prev = stackp; 224 stackp = sp; 225 stacknxt = sp->space; 226 stacknleft = newlen; 227 228 /* 229 * Stack marks pointing to the start of the old block 230 * must be relocated to point to the new block 231 */ 232 xmark = markp; 233 while (xmark != NULL && xmark->stackp == oldstackp) { 234 xmark->stackp = stackp; 235 xmark->stacknxt = stacknxt; 236 xmark->stacknleft = stacknleft; 237 xmark = xmark->marknext; 238 } 239 INTON; 240 } else { 241 char *oldspace = stacknxt; 242 int oldlen = stacknleft; 243 char *p = stalloc(newlen); 244 245 (void)memcpy(p, oldspace, oldlen); 246 stacknxt = p; /* free the space */ 247 stacknleft += newlen; /* we just allocated */ 248 } 249 } 250 251 void 252 grabstackblock(int len) 253 { 254 len = SHELL_ALIGN(len); 255 stacknxt += len; 256 stacknleft -= len; 257 } 258 259 /* 260 * The following routines are somewhat easier to use than the above. 261 * The user declares a variable of type STACKSTR, which may be declared 262 * to be a register. The macro STARTSTACKSTR initializes things. Then 263 * the user uses the macro STPUTC to add characters to the string. In 264 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 265 * grown as necessary. When the user is done, she can just leave the 266 * string there and refer to it using stackblock(). Or she can allocate 267 * the space for it using grabstackstr(). If it is necessary to allow 268 * someone else to use the stack temporarily and then continue to grow 269 * the string, the user should use grabstack to allocate the space, and 270 * then call ungrabstr(p) to return to the previous mode of operation. 271 * 272 * USTPUTC is like STPUTC except that it doesn't check for overflow. 273 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 274 * is space for at least one character. 275 */ 276 277 char * 278 growstackstr(void) 279 { 280 int len = stackblocksize(); 281 if (herefd >= 0 && len >= 1024) { 282 xwrite(herefd, stackblock(), len); 283 sstrnleft = len - 1; 284 return stackblock(); 285 } 286 growstackblock(); 287 sstrnleft = stackblocksize() - len - 1; 288 return stackblock() + len; 289 } 290 291 /* 292 * Called from CHECKSTRSPACE. 293 */ 294 295 char * 296 makestrspace(void) 297 { 298 int len = stackblocksize() - sstrnleft; 299 growstackblock(); 300 sstrnleft = stackblocksize() - len; 301 return stackblock() + len; 302 } 303 304 void 305 ungrabstackstr(char *s, char *p) 306 { 307 stacknleft += stacknxt - s; 308 stacknxt = s; 309 sstrnleft = stacknleft - (p - s); 310 311 } 312