memalloc.c revision 216743
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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33#ifndef lint 34#if 0 35static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95"; 36#endif 37#endif /* not lint */ 38#include <sys/cdefs.h> 39__FBSDID("$FreeBSD: head/bin/sh/memalloc.c 216743 2010-12-27 22:18:27Z jilles $"); 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 55pointer 56ckmalloc(size_t 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 73pointer 74ckrealloc(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 84void 85ckfree(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 97char * 98savestr(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 120struct stack_block { 121 struct stack_block *prev; 122 /* Data follows */ 123}; 124#define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block))) 125 126static struct stack_block *stackp; 127static struct stackmark *markp; 128char *stacknxt; 129int stacknleft; 130char *sstrend; 131 132 133static void 134stnewblock(int nbytes) 135{ 136 struct stack_block *sp; 137 int allocsize; 138 139 if (nbytes < MINSIZE) 140 nbytes = MINSIZE; 141 142 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes); 143 144 INTOFF; 145 sp = ckmalloc(allocsize); 146 sp->prev = stackp; 147 stacknxt = SPACE(sp); 148 stacknleft = allocsize - (stacknxt - (char*)sp); 149 sstrend = stacknxt + stacknleft; 150 stackp = sp; 151 INTON; 152} 153 154 155pointer 156stalloc(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 170void 171stunalloc(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 183void 184setstackmark(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 194void 195popstackmark(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 sstrend = stacknxt + stacknleft; 209 INTON; 210} 211 212 213/* 214 * When the parser reads in a string, it wants to stick the string on the 215 * stack and only adjust the stack pointer when it knows how big the 216 * string is. Stackblock (defined in stack.h) returns a pointer to a block 217 * of space on top of the stack and stackblocklen returns the length of 218 * this block. Growstackblock will grow this space by at least one byte, 219 * possibly moving it (like realloc). Grabstackblock actually allocates the 220 * part of the block that has been used. 221 */ 222 223static void 224growstackblock(int min) 225{ 226 char *p; 227 int newlen; 228 char *oldspace; 229 int oldlen; 230 struct stack_block *sp; 231 struct stack_block *oldstackp; 232 struct stackmark *xmark; 233 234 if (min < stacknleft) 235 min = stacknleft; 236 if (min >= INT_MAX / 2 - ALIGN(sizeof(struct stack_block))) 237 error("Out of space"); 238 min += stacknleft; 239 min += ALIGN(sizeof(struct stack_block)); 240 newlen = 512; 241 while (newlen < min) 242 newlen <<= 1; 243 oldspace = stacknxt; 244 oldlen = stacknleft; 245 246 if (stackp != NULL && stacknxt == SPACE(stackp)) { 247 INTOFF; 248 oldstackp = stackp; 249 stackp = oldstackp->prev; 250 sp = ckrealloc((pointer)oldstackp, newlen); 251 sp->prev = stackp; 252 stackp = sp; 253 stacknxt = SPACE(sp); 254 stacknleft = newlen - (stacknxt - (char*)sp); 255 sstrend = stacknxt + stacknleft; 256 257 /* 258 * Stack marks pointing to the start of the old block 259 * must be relocated to point to the new block 260 */ 261 xmark = markp; 262 while (xmark != NULL && xmark->stackp == oldstackp) { 263 xmark->stackp = stackp; 264 xmark->stacknxt = stacknxt; 265 xmark->stacknleft = stacknleft; 266 xmark = xmark->marknext; 267 } 268 INTON; 269 } else { 270 newlen -= ALIGN(sizeof(struct stack_block)); 271 p = stalloc(newlen); 272 if (oldlen != 0) 273 memcpy(p, oldspace, oldlen); 274 stunalloc(p); 275 } 276} 277 278 279 280void 281grabstackblock(int len) 282{ 283 len = ALIGN(len); 284 stacknxt += len; 285 stacknleft -= len; 286} 287 288 289 290/* 291 * The following routines are somewhat easier to use that the above. 292 * The user declares a variable of type STACKSTR, which may be declared 293 * to be a register. The macro STARTSTACKSTR initializes things. Then 294 * the user uses the macro STPUTC to add characters to the string. In 295 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 296 * grown as necessary. When the user is done, she can just leave the 297 * string there and refer to it using stackblock(). Or she can allocate 298 * the space for it using grabstackstr(). If it is necessary to allow 299 * someone else to use the stack temporarily and then continue to grow 300 * the string, the user should use grabstack to allocate the space, and 301 * then call ungrabstr(p) to return to the previous mode of operation. 302 * 303 * USTPUTC is like STPUTC except that it doesn't check for overflow. 304 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 305 * is space for at least one character. 306 */ 307 308static char * 309growstrstackblock(int n, int min) 310{ 311 growstackblock(min); 312 return stackblock() + n; 313} 314 315char * 316growstackstr(void) 317{ 318 int len; 319 320 len = stackblocksize(); 321 return (growstrstackblock(len, 0)); 322} 323 324 325/* 326 * Called from CHECKSTRSPACE. 327 */ 328 329char * 330makestrspace(int min, char *p) 331{ 332 int len; 333 334 len = p - stackblock(); 335 return (growstrstackblock(len, min)); 336} 337 338 339char * 340stputbin(const char *data, int len, char *p) 341{ 342 CHECKSTRSPACE(len, p); 343 memcpy(p, data, len); 344 return (p + len); 345} 346 347char * 348stputs(const char *data, char *p) 349{ 350 return (stputbin(data, strlen(data), p)); 351} 352