1 /* $NetBSD: memalloc.c,v 1.35 2021/10/26 10:07:20 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 1.35 2021/10/26 10:07:20 kre Exp $"); 41 #endif 42 #endif /* not lint */ 43 44 #include <limits.h> 45 #include <stdarg.h> 46 #include <stdlib.h> 47 #include <unistd.h> 48 49 #include "shell.h" 50 #include "output.h" 51 #include "memalloc.h" 52 #include "error.h" 53 #include "machdep.h" 54 #include "mystring.h" 55 56 /* 57 * Like malloc, but returns an error when out of space. 58 */ 59 60 pointer 61 ckmalloc(size_t nbytes) 62 { 63 pointer p; 64 65 p = malloc(nbytes); 66 if (p == NULL) 67 error("Out of space"); 68 return p; 69 } 70 71 72 /* 73 * Same for realloc. 74 */ 75 76 pointer 77 ckrealloc(pointer p, int nbytes) 78 { 79 p = realloc(p, nbytes); 80 if (p == 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(const char *s) 92 { 93 char *p; 94 95 p = ckmalloc(strlen(s) + 1); 96 scopy(s, p); 97 return p; 98 } 99 100 101 /* 102 * Parse trees for commands are allocated in lifo order, so we use a stack 103 * to make this more efficient, and also to avoid all sorts of exception 104 * handling code to handle interrupts in the middle of a parse. 105 * 106 * The size 504 was chosen because the Ultrix malloc handles that size 107 * well. 108 */ 109 110 #define MINSIZE 504 /* minimum size of a block */ 111 112 struct stack_block { 113 struct stack_block *prev; 114 char space[MINSIZE]; 115 }; 116 117 struct stack_block stackbase; 118 struct stack_block *stackp = &stackbase; 119 struct stackmark *markp; 120 char *stacknxt = stackbase.space; 121 int stacknleft = MINSIZE; 122 int sstrnleft; 123 int herefd = -1; 124 125 pointer 126 stalloc(int nbytes) 127 { 128 char *p; 129 130 nbytes = SHELL_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 + blocksize); 140 sp->prev = stackp; 141 stacknxt = sp->space; 142 stacknleft = blocksize; 143 stackp = sp; 144 INTON; 145 } 146 INTOFF; 147 p = stacknxt; 148 stacknxt += nbytes; 149 stacknleft -= nbytes; 150 INTON; 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 /* save the current status of the sh stack */ 168 void 169 setstackmark(struct stackmark *mark) 170 { 171 mark->stackp = stackp; 172 mark->stacknxt = stacknxt; 173 mark->stacknleft = stacknleft; 174 mark->sstrnleft = sstrnleft; 175 mark->marknext = markp; 176 markp = mark; 177 } 178 179 /* reset the stack mark, and remove it from the list of marks */ 180 void 181 popstackmark(struct stackmark *mark) 182 { 183 INTOFF; 184 markp = mark->marknext; /* delete mark from the list */ 185 rststackmark(mark); /* and reset stack */ 186 INTON; 187 } 188 189 /* reset the shell stack to its state recorded in the stack mark */ 190 void 191 rststackmark(struct stackmark *mark) 192 { 193 struct stack_block *sp; 194 195 INTOFF; 196 while (stackp != mark->stackp) { 197 /* delete any recently allocated mem blocks */ 198 sp = stackp; 199 stackp = sp->prev; 200 ckfree(sp); 201 } 202 stacknxt = mark->stacknxt; 203 stacknleft = mark->stacknleft; 204 sstrnleft = mark->sstrnleft; 205 INTON; 206 } 207 208 209 /* 210 * When the parser reads in a string, it wants to stick the string on the 211 * stack and only adjust the stack pointer when it knows how big the 212 * string is. Stackblock (defined in stack.h) returns a pointer to a block 213 * of space on top of the stack and stackblocklen returns the length of 214 * this block. Growstackblock will grow this space by at least one byte, 215 * possibly moving it (like realloc). Grabstackblock actually allocates the 216 * part of the block that has been used. 217 */ 218 219 void 220 growstackblock(void) 221 { 222 int newlen = SHELL_ALIGN(stacknleft * 2 + 100); 223 224 INTOFF; 225 if (stacknxt == stackp->space && stackp != &stackbase) { 226 struct stack_block *oldstackp; 227 struct stackmark *xmark; 228 struct stack_block *sp; 229 230 oldstackp = stackp; 231 sp = stackp; 232 stackp = sp->prev; 233 sp = ckrealloc((pointer)sp, 234 sizeof(struct stack_block) - MINSIZE + newlen); 235 sp->prev = stackp; 236 stackp = sp; 237 stacknxt = sp->space; 238 sstrnleft += newlen - stacknleft; 239 stacknleft = newlen; 240 241 /* 242 * Stack marks pointing to the start of the old block 243 * must be relocated to point to the new block 244 */ 245 xmark = markp; 246 while (xmark != NULL && xmark->stackp == oldstackp) { 247 xmark->stackp = stackp; 248 xmark->stacknxt = stacknxt; 249 xmark->sstrnleft += stacknleft - xmark->stacknleft; 250 xmark->stacknleft = stacknleft; 251 xmark = xmark->marknext; 252 } 253 } else { 254 char *oldspace = stacknxt; 255 int oldlen = stacknleft; 256 char *p = stalloc(newlen); 257 258 (void)memcpy(p, oldspace, oldlen); 259 stacknxt = p; /* free the space */ 260 stacknleft += newlen; /* we just allocated */ 261 } 262 INTON; 263 } 264 265 void 266 grabstackblock(int len) 267 { 268 len = SHELL_ALIGN(len); 269 INTOFF; 270 stacknxt += len; 271 stacknleft -= len; 272 INTON; 273 } 274 275 /* 276 * The following routines are somewhat easier to use than the above. 277 * The user declares a variable of type STACKSTR, which may be declared 278 * to be a register. The macro STARTSTACKSTR initializes things. Then 279 * the user uses the macro STPUTC to add characters to the string. In 280 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 281 * grown as necessary. When the user is done, she can just leave the 282 * string there and refer to it using stackblock(). Or she can allocate 283 * the space for it using grabstackstr(). If it is necessary to allow 284 * someone else to use the stack temporarily and then continue to grow 285 * the string, the user should use grabstack to allocate the space, and 286 * then call ungrabstr(p) to return to the previous mode of operation. 287 * 288 * USTPUTC is like STPUTC except that it doesn't check for overflow. 289 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 290 * is space for at least one character. 291 */ 292 293 char * 294 growstackstr(void) 295 { 296 int len = stackblocksize(); 297 if (herefd >= 0 && len >= 1024) { 298 xwrite(herefd, stackblock(), len); 299 sstrnleft = len - 1; 300 return stackblock(); 301 } 302 growstackblock(); 303 sstrnleft = stackblocksize() - len - 1; 304 return stackblock() + len; 305 } 306 307 /* 308 * Called from CHECKSTRSPACE. 309 */ 310 311 char * 312 makestrspace(void) 313 { 314 int len = stackblocksize() - sstrnleft; 315 growstackblock(); 316 sstrnleft = stackblocksize() - len; 317 return stackblock() + len; 318 } 319 320 /* 321 * Note that this only works to release stack space for reuse 322 * if nothing else has allocated space on the stack since the grabstackstr() 323 * 324 * "s" is the start of the area to be released, and "p" represents the end 325 * of the string we have stored beyond there and are now releasing. 326 * (ie: "p" should be the same as in the call to grabstackstr()). 327 * 328 * stunalloc(s) and ungrabstackstr(s, p) are almost interchangable after 329 * a grabstackstr(), however the latter also returns string space so we 330 * can just continue with STPUTC() etc without needing a new STARTSTACKSTR(s) 331 */ 332 void 333 ungrabstackstr(char *s, char *p) 334 { 335 #ifdef DEBUG 336 if (s < stacknxt || stacknxt + stacknleft < s) 337 abort(); 338 #endif 339 stacknleft += stacknxt - s; 340 stacknxt = s; 341 sstrnleft = stacknleft - (p - s); 342 } 343 344 /* 345 * Save the concat of a sequence of strings in stack space 346 * 347 * The first arg (if not NULL) is a pointer to where the final string 348 * length will be returned. 349 * 350 * Remaining args are pointers to strings - sufficient space to hold 351 * the concat of the strings is allocated on the stack, the strings 352 * are copied into that space, and a pointer to its start is retured. 353 * The arg list is terminated with STSTRC_END. 354 * 355 * Use stunalloc(string) (in proper sequence) to release the string 356 */ 357 char * 358 ststrcat(size_t *lp, ...) 359 { 360 va_list ap; 361 const char *arg; 362 size_t len, tlen = 0, alen[8]; 363 char *str, *nxt; 364 unsigned int n; 365 366 n = 0; 367 va_start(ap, lp); 368 arg = va_arg(ap, const char *); 369 while (arg != STSTRC_END) { 370 len = strlen(arg); 371 if (n < sizeof(alen)/sizeof(alen[0])) 372 alen[n++] = len; 373 tlen += len; 374 arg = va_arg(ap, const char *); 375 } 376 va_end(ap); 377 378 if (lp != NULL) 379 *lp = tlen; 380 381 if (tlen >= INT_MAX) 382 error("ststrcat() over length botch"); 383 str = (char *)stalloc((int)tlen + 1); /* 1 for \0 */ 384 str[tlen] = '\0'; /* in case of no args */ 385 386 n = 0; 387 nxt = str; 388 va_start(ap, lp); 389 arg = va_arg(ap, const char *); 390 while (arg != STSTRC_END) { 391 if (n < sizeof(alen)/sizeof(alen[0])) 392 len = alen[n++]; 393 else 394 len = strlen(arg); 395 396 scopy(arg, nxt); 397 nxt += len; 398 399 arg = va_arg(ap, const char *); 400 } 401 va_end(ap); 402 403 return str; 404 } 405 406