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 * @(#)memalloc.c 8.3 (Berkeley) 5/4/95 37 * $FreeBSD: src/bin/sh/memalloc.c,v 1.27 2005/10/28 10:45:19 stefanf Exp $ 38 * $DragonFly: src/bin/sh/memalloc.c,v 1.5 2007/01/14 03:59:57 pavalos Exp $ 39 */ 40 41 #include <sys/param.h> 42 #include "shell.h" 43 #include "output.h" 44 #include "memalloc.h" 45 #include "error.h" 46 #include "mystring.h" 47 #include "expand.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(int nbytes) 57 { 58 pointer p; 59 60 INTOFF; 61 p = malloc(nbytes); 62 INTON; 63 if (p == NULL) 64 error("Out of space"); 65 return p; 66 } 67 68 69 /* 70 * Same for realloc. 71 */ 72 73 pointer 74 ckrealloc(pointer p, int nbytes) 75 { 76 INTOFF; 77 p = realloc(p, nbytes); 78 INTON; 79 if (p == NULL) 80 error("Out of space"); 81 return p; 82 } 83 84 void 85 ckfree(pointer p) 86 { 87 INTOFF; 88 free(p); 89 INTON; 90 } 91 92 93 /* 94 * Make a copy of a string in safe storage. 95 */ 96 97 char * 98 savestr(const char *s) 99 { 100 char *p; 101 102 p = ckmalloc(strlen(s) + 1); 103 scopy(s, p); 104 return p; 105 } 106 107 108 /* 109 * Parse trees for commands are allocated in lifo order, so we use a stack 110 * to make this more efficient, and also to avoid all sorts of exception 111 * handling code to handle interrupts in the middle of a parse. 112 * 113 * The size 496 was chosen because with 16-byte alignment the total size 114 * for the allocated block is 512. 115 */ 116 117 #define MINSIZE 496 /* minimum size of a block. */ 118 119 120 struct stack_block { 121 struct stack_block *prev; 122 /* Data follows */ 123 }; 124 #define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block))) 125 126 STATIC struct stack_block *stackp; 127 STATIC struct stackmark *markp; 128 char *stacknxt; 129 int stacknleft; 130 int sstrnleft; 131 int herefd = -1; 132 133 134 static void 135 stnewblock(int nbytes) 136 { 137 struct stack_block *sp; 138 int allocsize; 139 140 if (nbytes < MINSIZE) 141 nbytes = MINSIZE; 142 143 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes); 144 145 INTOFF; 146 sp = ckmalloc(allocsize); 147 sp->prev = stackp; 148 stacknxt = SPACE(sp); 149 stacknleft = allocsize - (stacknxt - (char*)sp); 150 stackp = sp; 151 INTON; 152 } 153 154 155 pointer 156 stalloc(int nbytes) 157 { 158 char *p; 159 160 nbytes = ALIGN(nbytes); 161 if (nbytes > stacknleft) 162 stnewblock(nbytes); 163 p = stacknxt; 164 stacknxt += nbytes; 165 stacknleft -= nbytes; 166 return p; 167 } 168 169 170 void 171 stunalloc(pointer p) 172 { 173 if (p == NULL) { /*DEBUG */ 174 write(STDERR_FILENO, "stunalloc\n", 10); 175 abort(); 176 } 177 stacknleft += stacknxt - (char *)p; 178 stacknxt = p; 179 } 180 181 182 183 void 184 setstackmark(struct stackmark *mark) 185 { 186 mark->stackp = stackp; 187 mark->stacknxt = stacknxt; 188 mark->stacknleft = stacknleft; 189 mark->marknext = markp; 190 markp = mark; 191 } 192 193 194 void 195 popstackmark(struct stackmark *mark) 196 { 197 struct stack_block *sp; 198 199 INTOFF; 200 markp = mark->marknext; 201 while (stackp != mark->stackp) { 202 sp = stackp; 203 stackp = sp->prev; 204 ckfree(sp); 205 } 206 stacknxt = mark->stacknxt; 207 stacknleft = mark->stacknleft; 208 INTON; 209 } 210 211 212 /* 213 * When the parser reads in a string, it wants to stick the string on the 214 * stack and only adjust the stack pointer when it knows how big the 215 * string is. Stackblock (defined in stack.h) returns a pointer to a block 216 * of space on top of the stack and stackblocklen returns the length of 217 * this block. Growstackblock will grow this space by at least one byte, 218 * possibly moving it (like realloc). Grabstackblock actually allocates the 219 * part of the block that has been used. 220 */ 221 222 void 223 growstackblock(void) 224 { 225 char *p; 226 int newlen; 227 char *oldspace; 228 int oldlen; 229 struct stack_block *sp; 230 struct stack_block *oldstackp; 231 struct stackmark *xmark; 232 233 newlen = (stacknleft == 0) ? MINSIZE : stacknleft * 2 + 100; 234 newlen = ALIGN(newlen); 235 oldspace = stacknxt; 236 oldlen = stacknleft; 237 238 if (stackp != NULL && stacknxt == SPACE(stackp)) { 239 INTOFF; 240 oldstackp = stackp; 241 stackp = oldstackp->prev; 242 sp = ckrealloc((pointer)oldstackp, newlen); 243 sp->prev = stackp; 244 stackp = sp; 245 stacknxt = SPACE(sp); 246 stacknleft = newlen - (stacknxt - (char*)sp); 247 248 /* 249 * Stack marks pointing to the start of the old block 250 * must be relocated to point to the new block 251 */ 252 xmark = markp; 253 while (xmark != NULL && xmark->stackp == oldstackp) { 254 xmark->stackp = stackp; 255 xmark->stacknxt = stacknxt; 256 xmark->stacknleft = stacknleft; 257 xmark = xmark->marknext; 258 } 259 INTON; 260 } else { 261 p = stalloc(newlen); 262 if (oldlen != 0) 263 memcpy(p, oldspace, oldlen); 264 stunalloc(p); 265 } 266 } 267 268 269 270 void 271 grabstackblock(int len) 272 { 273 len = ALIGN(len); 274 stacknxt += len; 275 stacknleft -= len; 276 } 277 278 279 280 /* 281 * The following routines are somewhat easier to use that the above. 282 * The user declares a variable of type STACKSTR, which may be declared 283 * to be a register. The macro STARTSTACKSTR initializes things. Then 284 * the user uses the macro STPUTC to add characters to the string. In 285 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 286 * grown as necessary. When the user is done, she can just leave the 287 * string there and refer to it using stackblock(). Or she can allocate 288 * the space for it using grabstackstr(). If it is necessary to allow 289 * someone else to use the stack temporarily and then continue to grow 290 * the string, the user should use grabstack to allocate the space, and 291 * then call ungrabstr(p) to return to the previous mode of operation. 292 * 293 * USTPUTC is like STPUTC except that it doesn't check for overflow. 294 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 295 * is space for at least one character. 296 */ 297 298 299 char * 300 growstackstr(void) 301 { 302 int len; 303 304 len = stackblocksize(); 305 if (herefd >= 0 && len >= 1024) { 306 xwrite(herefd, stackblock(), len); 307 sstrnleft = len - 1; 308 return stackblock(); 309 } 310 growstackblock(); 311 sstrnleft = stackblocksize() - len - 1; 312 return stackblock() + len; 313 } 314 315 316 /* 317 * Called from CHECKSTRSPACE. 318 */ 319 320 char * 321 makestrspace(void) 322 { 323 int len; 324 325 len = stackblocksize() - sstrnleft; 326 growstackblock(); 327 sstrnleft = stackblocksize() - len; 328 return stackblock() + len; 329 } 330 331 332 333 void 334 ungrabstackstr(char *s, char *p) 335 { 336 stacknleft += stacknxt - s; 337 stacknxt = s; 338 sstrnleft = stacknleft - (p - s); 339 } 340