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 #endif /* not lint */ 42 #include <sys/cdefs.h> 43 __FBSDID("$FreeBSD: src/bin/sh/memalloc.c,v 1.15.2.2 2002/07/19 04:38:51 tjr Exp $"); 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 "expand.h" 52 #include <stdlib.h> 53 #include <unistd.h> 54 55 /* 56 * Like malloc, but returns an error when out of space. 57 */ 58 59 pointer 60 ckmalloc(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(pointer p, int nbytes) 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(char *s) 89 { 90 char *p; 91 92 p = ckmalloc(strlen(s) + 1); 93 scopy(s, p); 94 return p; 95 } 96 97 98 /* 99 * Parse trees for commands are allocated in lifo order, so we use a stack 100 * to make this more efficient, and also to avoid all sorts of exception 101 * handling code to handle interrupts in the middle of a parse. 102 * 103 * The size 504 was chosen because the Ultrix malloc handles that size 104 * well. 105 */ 106 107 #define MINSIZE 504 /* minimum size of a block */ 108 109 110 struct stack_block { 111 struct stack_block *prev; 112 char space[MINSIZE]; 113 }; 114 115 struct stack_block stackbase; 116 struct stack_block *stackp = &stackbase; 117 struct stackmark *markp; 118 char *stacknxt = stackbase.space; 119 int stacknleft = MINSIZE; 120 int sstrnleft; 121 int herefd = -1; 122 123 124 125 pointer 126 stalloc(int nbytes) 127 { 128 char *p; 129 130 nbytes = ALIGN(nbytes); 131 if (nbytes > stacknleft) { 132 int blocksize; 133 struct stack_block *sp; 134 135 blocksize = nbytes; 136 if (blocksize < MINSIZE) 137 blocksize = MINSIZE; 138 INTOFF; 139 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + 140 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(pointer p) 156 { 157 if (p == NULL) { /*DEBUG */ 158 write(STDERR_FILENO, "stunalloc\n", 10); 159 abort(); 160 } 161 stacknleft += stacknxt - (char *)p; 162 stacknxt = p; 163 } 164 165 166 167 void 168 setstackmark(struct stackmark *mark) 169 { 170 mark->stackp = stackp; 171 mark->stacknxt = stacknxt; 172 mark->stacknleft = stacknleft; 173 mark->marknext = markp; 174 markp = mark; 175 } 176 177 178 void 179 popstackmark(struct stackmark *mark) 180 { 181 struct stack_block *sp; 182 183 INTOFF; 184 markp = mark->marknext; 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(void) 208 { 209 char *p; 210 int newlen; 211 char *oldspace; 212 int oldlen; 213 struct stack_block *sp; 214 struct stack_block *oldstackp; 215 216 newlen = ALIGN(stacknleft * 2 + 100); 217 oldspace = stacknxt; 218 oldlen = stacknleft; 219 220 if (stacknxt == stackp->space && stackp != &stackbase) { 221 INTOFF; 222 oldstackp = stackp; 223 sp = stackp; 224 stackp = sp->prev; 225 sp = ckrealloc((pointer)sp, sizeof(struct stack_block) - 226 MINSIZE + newlen); 227 sp->prev = stackp; 228 stackp = sp; 229 stacknxt = sp->space; 230 stacknleft = newlen; 231 { 232 /* Stack marks pointing to the start of the old block 233 * must be relocated to point to the new block 234 */ 235 struct stackmark *xmark; 236 xmark = markp; 237 while (xmark != NULL && xmark->stackp == oldstackp) { 238 xmark->stackp = stackp; 239 xmark->stacknxt = stacknxt; 240 xmark->stacknleft = stacknleft; 241 xmark = xmark->marknext; 242 } 243 } 244 INTON; 245 } else { 246 p = stalloc(newlen); 247 memcpy(p, oldspace, oldlen); 248 stacknxt = p; /* free the space */ 249 stacknleft += newlen; /* we just allocated */ 250 } 251 } 252 253 254 255 void 256 grabstackblock(int len) 257 { 258 len = ALIGN(len); 259 stacknxt += len; 260 stacknleft -= len; 261 } 262 263 264 265 /* 266 * The following routines are somewhat easier to use that the above. 267 * The user declares a variable of type STACKSTR, which may be declared 268 * to be a register. The macro STARTSTACKSTR initializes things. Then 269 * the user uses the macro STPUTC to add characters to the string. In 270 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 271 * grown as necessary. When the user is done, she can just leave the 272 * string there and refer to it using stackblock(). Or she can allocate 273 * the space for it using grabstackstr(). If it is necessary to allow 274 * someone else to use the stack temporarily and then continue to grow 275 * the string, the user should use grabstack to allocate the space, and 276 * then call ungrabstr(p) to return to the previous mode of operation. 277 * 278 * USTPUTC is like STPUTC except that it doesn't check for overflow. 279 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 280 * is space for at least one character. 281 */ 282 283 284 char * 285 growstackstr(void) 286 { 287 int len; 288 289 len = stackblocksize(); 290 if (herefd >= 0 && len >= 1024) { 291 xwrite(herefd, stackblock(), len); 292 sstrnleft = len - 1; 293 return stackblock(); 294 } 295 growstackblock(); 296 sstrnleft = stackblocksize() - len - 1; 297 return stackblock() + len; 298 } 299 300 301 /* 302 * Called from CHECKSTRSPACE. 303 */ 304 305 char * 306 makestrspace(void) 307 { 308 int len; 309 310 len = stackblocksize() - sstrnleft; 311 growstackblock(); 312 sstrnleft = stackblocksize() - len; 313 return stackblock() + len; 314 } 315 316 317 318 void 319 ungrabstackstr(char *s, char *p) 320 { 321 stacknleft += stacknxt - s; 322 stacknxt = s; 323 sstrnleft = stacknleft - (p - s); 324 } 325