1 /* $NetBSD: memalloc.c,v 1.33 2019/02/09 03:35:55 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 1.33 2019/02/09 03:35:55 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 INTOFF; 145 p = stacknxt; 146 stacknxt += nbytes; 147 stacknleft -= nbytes; 148 INTON; 149 return p; 150 } 151 152 153 void 154 stunalloc(pointer p) 155 { 156 if (p == NULL) { /*DEBUG */ 157 write(2, "stunalloc\n", 10); 158 abort(); 159 } 160 stacknleft += stacknxt - (char *)p; 161 stacknxt = p; 162 } 163 164 165 /* save the current status of the sh stack */ 166 void 167 setstackmark(struct stackmark *mark) 168 { 169 mark->stackp = stackp; 170 mark->stacknxt = stacknxt; 171 mark->stacknleft = stacknleft; 172 mark->sstrnleft = sstrnleft; 173 mark->marknext = markp; 174 markp = mark; 175 } 176 177 /* reset the stack mark, and remove it from the list of marks */ 178 void 179 popstackmark(struct stackmark *mark) 180 { 181 INTOFF; 182 markp = mark->marknext; /* delete mark from the list */ 183 rststackmark(mark); /* and reset stack */ 184 INTON; 185 } 186 187 /* reset the shell stack to its state recorded in the stack mark */ 188 void 189 rststackmark(struct stackmark *mark) 190 { 191 struct stack_block *sp; 192 193 INTOFF; 194 while (stackp != mark->stackp) { 195 /* delete any recently allocated mem blocks */ 196 sp = stackp; 197 stackp = sp->prev; 198 ckfree(sp); 199 } 200 stacknxt = mark->stacknxt; 201 stacknleft = mark->stacknleft; 202 sstrnleft = mark->sstrnleft; 203 INTON; 204 } 205 206 207 /* 208 * When the parser reads in a string, it wants to stick the string on the 209 * stack and only adjust the stack pointer when it knows how big the 210 * string is. Stackblock (defined in stack.h) returns a pointer to a block 211 * of space on top of the stack and stackblocklen returns the length of 212 * this block. Growstackblock will grow this space by at least one byte, 213 * possibly moving it (like realloc). Grabstackblock actually allocates the 214 * part of the block that has been used. 215 */ 216 217 void 218 growstackblock(void) 219 { 220 int newlen = SHELL_ALIGN(stacknleft * 2 + 100); 221 222 INTOFF; 223 if (stacknxt == stackp->space && stackp != &stackbase) { 224 struct stack_block *oldstackp; 225 struct stackmark *xmark; 226 struct stack_block *sp; 227 228 oldstackp = stackp; 229 sp = stackp; 230 stackp = sp->prev; 231 sp = ckrealloc((pointer)sp, 232 sizeof(struct stack_block) - MINSIZE + newlen); 233 sp->prev = stackp; 234 stackp = sp; 235 stacknxt = sp->space; 236 sstrnleft += newlen - stacknleft; 237 stacknleft = newlen; 238 239 /* 240 * Stack marks pointing to the start of the old block 241 * must be relocated to point to the new block 242 */ 243 xmark = markp; 244 while (xmark != NULL && xmark->stackp == oldstackp) { 245 xmark->stackp = stackp; 246 xmark->stacknxt = stacknxt; 247 xmark->sstrnleft += stacknleft - xmark->stacknleft; 248 xmark->stacknleft = stacknleft; 249 xmark = xmark->marknext; 250 } 251 } else { 252 char *oldspace = stacknxt; 253 int oldlen = stacknleft; 254 char *p = stalloc(newlen); 255 256 (void)memcpy(p, oldspace, oldlen); 257 stacknxt = p; /* free the space */ 258 stacknleft += newlen; /* we just allocated */ 259 } 260 INTON; 261 } 262 263 void 264 grabstackblock(int len) 265 { 266 len = SHELL_ALIGN(len); 267 INTOFF; 268 stacknxt += len; 269 stacknleft -= len; 270 INTON; 271 } 272 273 /* 274 * The following routines are somewhat easier to use than the above. 275 * The user declares a variable of type STACKSTR, which may be declared 276 * to be a register. The macro STARTSTACKSTR initializes things. Then 277 * the user uses the macro STPUTC to add characters to the string. In 278 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 279 * grown as necessary. When the user is done, she can just leave the 280 * string there and refer to it using stackblock(). Or she can allocate 281 * the space for it using grabstackstr(). If it is necessary to allow 282 * someone else to use the stack temporarily and then continue to grow 283 * the string, the user should use grabstack to allocate the space, and 284 * then call ungrabstr(p) to return to the previous mode of operation. 285 * 286 * USTPUTC is like STPUTC except that it doesn't check for overflow. 287 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 288 * is space for at least one character. 289 */ 290 291 char * 292 growstackstr(void) 293 { 294 int len = stackblocksize(); 295 if (herefd >= 0 && len >= 1024) { 296 xwrite(herefd, stackblock(), len); 297 sstrnleft = len - 1; 298 return stackblock(); 299 } 300 growstackblock(); 301 sstrnleft = stackblocksize() - len - 1; 302 return stackblock() + len; 303 } 304 305 /* 306 * Called from CHECKSTRSPACE. 307 */ 308 309 char * 310 makestrspace(void) 311 { 312 int len = stackblocksize() - sstrnleft; 313 growstackblock(); 314 sstrnleft = stackblocksize() - len; 315 return stackblock() + len; 316 } 317 318 /* 319 * Note that this only works to release stack space for reuse 320 * if nothing else has allocated space on the stack since the grabstackstr() 321 * 322 * "s" is the start of the area to be released, and "p" represents the end 323 * of the string we have stored beyond there and are now releasing. 324 * (ie: "p" should be the same as in the call to grabstackstr()). 325 * 326 * stunalloc(s) and ungrabstackstr(s, p) are almost interchangable after 327 * a grabstackstr(), however the latter also returns string space so we 328 * can just continue with STPUTC() etc without needing a new STARTSTACKSTR(s) 329 */ 330 void 331 ungrabstackstr(char *s, char *p) 332 { 333 #ifdef DEBUG 334 if (s < stacknxt || stacknxt + stacknleft < s) 335 abort(); 336 #endif 337 stacknleft += stacknxt - s; 338 stacknxt = s; 339 sstrnleft = stacknleft - (p - s); 340 } 341