1 /* $NetBSD: memalloc.c,v 1.30 2017/06/17 07:22:12 kre 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. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #ifndef lint 37 #if 0 38 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95"; 39 #else 40 __RCSID("$NetBSD: memalloc.c,v 1.30 2017/06/17 07:22:12 kre Exp $"); 41 #endif 42 #endif /* not lint */ 43 44 #include <stdlib.h> 45 #include <unistd.h> 46 47 #include "shell.h" 48 #include "output.h" 49 #include "memalloc.h" 50 #include "error.h" 51 #include "machdep.h" 52 #include "mystring.h" 53 54 /* 55 * Like malloc, but returns an error when out of space. 56 */ 57 58 pointer 59 ckmalloc(size_t nbytes) 60 { 61 pointer p; 62 63 p = malloc(nbytes); 64 if (p == 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 p = realloc(p, nbytes); 78 if (p == NULL) 79 error("Out of space"); 80 return p; 81 } 82 83 84 /* 85 * Make a copy of a string in safe storage. 86 */ 87 88 char * 89 savestr(const char *s) 90 { 91 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 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 pointer 124 stalloc(int nbytes) 125 { 126 char *p; 127 128 nbytes = SHELL_ALIGN(nbytes); 129 if (nbytes > stacknleft) { 130 int blocksize; 131 struct stack_block *sp; 132 133 blocksize = nbytes; 134 if (blocksize < MINSIZE) 135 blocksize = MINSIZE; 136 INTOFF; 137 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize); 138 sp->prev = stackp; 139 stacknxt = sp->space; 140 stacknleft = blocksize; 141 stackp = sp; 142 INTON; 143 } 144 p = stacknxt; 145 stacknxt += nbytes; 146 stacknleft -= nbytes; 147 return p; 148 } 149 150 151 void 152 stunalloc(pointer p) 153 { 154 if (p == NULL) { /*DEBUG */ 155 write(2, "stunalloc\n", 10); 156 abort(); 157 } 158 stacknleft += stacknxt - (char *)p; 159 stacknxt = p; 160 } 161 162 163 164 void 165 setstackmark(struct stackmark *mark) 166 { 167 mark->stackp = stackp; 168 mark->stacknxt = stacknxt; 169 mark->stacknleft = stacknleft; 170 mark->sstrnleft = sstrnleft; 171 mark->marknext = markp; 172 markp = mark; 173 } 174 175 176 void 177 popstackmark(struct stackmark *mark) 178 { 179 struct stack_block *sp; 180 181 INTOFF; 182 markp = mark->marknext; 183 while (stackp != mark->stackp) { 184 sp = stackp; 185 stackp = sp->prev; 186 ckfree(sp); 187 } 188 stacknxt = mark->stacknxt; 189 stacknleft = mark->stacknleft; 190 sstrnleft = mark->sstrnleft; 191 INTON; 192 } 193 194 195 /* 196 * When the parser reads in a string, it wants to stick the string on the 197 * stack and only adjust the stack pointer when it knows how big the 198 * string is. Stackblock (defined in stack.h) returns a pointer to a block 199 * of space on top of the stack and stackblocklen returns the length of 200 * this block. Growstackblock will grow this space by at least one byte, 201 * possibly moving it (like realloc). Grabstackblock actually allocates the 202 * part of the block that has been used. 203 */ 204 205 void 206 growstackblock(void) 207 { 208 int newlen = SHELL_ALIGN(stacknleft * 2 + 100); 209 210 if (stacknxt == stackp->space && stackp != &stackbase) { 211 struct stack_block *oldstackp; 212 struct stackmark *xmark; 213 struct stack_block *sp; 214 215 INTOFF; 216 oldstackp = stackp; 217 sp = stackp; 218 stackp = sp->prev; 219 sp = ckrealloc((pointer)sp, 220 sizeof(struct stack_block) - MINSIZE + newlen); 221 sp->prev = stackp; 222 stackp = sp; 223 stacknxt = sp->space; 224 stacknleft = newlen; 225 226 /* 227 * Stack marks pointing to the start of the old block 228 * must be relocated to point to the new block 229 */ 230 xmark = markp; 231 while (xmark != NULL && xmark->stackp == oldstackp) { 232 xmark->stackp = stackp; 233 xmark->stacknxt = stacknxt; 234 xmark->stacknleft = stacknleft; 235 xmark = xmark->marknext; 236 } 237 INTON; 238 } else { 239 char *oldspace = stacknxt; 240 int oldlen = stacknleft; 241 char *p = stalloc(newlen); 242 243 (void)memcpy(p, oldspace, oldlen); 244 stacknxt = p; /* free the space */ 245 stacknleft += newlen; /* we just allocated */ 246 } 247 } 248 249 void 250 grabstackblock(int len) 251 { 252 len = SHELL_ALIGN(len); 253 stacknxt += len; 254 stacknleft -= len; 255 } 256 257 /* 258 * The following routines are somewhat easier to use than the above. 259 * The user declares a variable of type STACKSTR, which may be declared 260 * to be a register. The macro STARTSTACKSTR initializes things. Then 261 * the user uses the macro STPUTC to add characters to the string. In 262 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 263 * grown as necessary. When the user is done, she can just leave the 264 * string there and refer to it using stackblock(). Or she can allocate 265 * the space for it using grabstackstr(). If it is necessary to allow 266 * someone else to use the stack temporarily and then continue to grow 267 * the string, the user should use grabstack to allocate the space, and 268 * then call ungrabstr(p) to return to the previous mode of operation. 269 * 270 * USTPUTC is like STPUTC except that it doesn't check for overflow. 271 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 272 * is space for at least one character. 273 */ 274 275 char * 276 growstackstr(void) 277 { 278 int len = stackblocksize(); 279 if (herefd >= 0 && len >= 1024) { 280 xwrite(herefd, stackblock(), len); 281 sstrnleft = len - 1; 282 return stackblock(); 283 } 284 growstackblock(); 285 sstrnleft = stackblocksize() - len - 1; 286 return stackblock() + len; 287 } 288 289 /* 290 * Called from CHECKSTRSPACE. 291 */ 292 293 char * 294 makestrspace(void) 295 { 296 int len = stackblocksize() - sstrnleft; 297 growstackblock(); 298 sstrnleft = stackblocksize() - len; 299 return stackblock() + len; 300 } 301 302 /* 303 * Note that this only works to release stack space for reuse 304 * if nothing else has allocated space on the stack since the grabstackstr() 305 * 306 * "s" is the start of the area to be released, and "p" represents the end 307 * of the string we have stored beyond there and are now releasing. 308 * (ie: "p" should be the same as in the call to grabstackstr()). 309 * 310 * stunalloc(s) and ungrabstackstr(s, p) are almost interchangable after 311 * a grabstackstr(), however the latter also returns string space so we 312 * can just continue with STPUTC() etc without needing a new STARTSTACKSTR(s) 313 */ 314 void 315 ungrabstackstr(char *s, char *p) 316 { 317 #ifdef DEBUG 318 if (s < stacknxt || stacknxt + stacknleft < s) 319 abort(); 320 #endif 321 stacknleft += stacknxt - s; 322 stacknxt = s; 323 sstrnleft = stacknleft - (p - s); 324 } 325