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. 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 * @(#)memalloc.c 8.3 (Berkeley) 5/4/95 33 * $FreeBSD: head/bin/sh/memalloc.c 250527 2013-05-11 20:51:00Z jilles $ 34 */ 35 36 #include <sys/param.h> 37 #include "shell.h" 38 #include "output.h" 39 #include "memalloc.h" 40 #include "error.h" 41 #include "mystring.h" 42 #include "expand.h" 43 #include <stdlib.h> 44 #include <unistd.h> 45 46 /* 47 * Like malloc, but returns an error when out of space. 48 */ 49 50 pointer 51 ckmalloc(size_t nbytes) 52 { 53 pointer p; 54 55 INTOFF; 56 p = malloc(nbytes); 57 INTON; 58 if (p == NULL) 59 error("Out of space"); 60 return p; 61 } 62 63 64 /* 65 * Same for realloc. 66 */ 67 68 pointer 69 ckrealloc(pointer p, int nbytes) 70 { 71 INTOFF; 72 p = realloc(p, nbytes); 73 INTON; 74 if (p == NULL) 75 error("Out of space"); 76 return p; 77 } 78 79 void 80 ckfree(pointer p) 81 { 82 INTOFF; 83 free(p); 84 INTON; 85 } 86 87 88 /* 89 * Make a copy of a string in safe storage. 90 */ 91 92 char * 93 savestr(const char *s) 94 { 95 char *p; 96 97 p = ckmalloc(strlen(s) + 1); 98 scopy(s, p); 99 return p; 100 } 101 102 103 /* 104 * Parse trees for commands are allocated in lifo order, so we use a stack 105 * to make this more efficient, and also to avoid all sorts of exception 106 * handling code to handle interrupts in the middle of a parse. 107 * 108 * The size 496 was chosen because with 16-byte alignment the total size 109 * for the allocated block is 512. 110 */ 111 112 #define MINSIZE 496 /* minimum size of a block. */ 113 114 115 struct stack_block { 116 struct stack_block *prev; 117 /* Data follows */ 118 }; 119 #define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block))) 120 121 static struct stack_block *stackp; 122 char *stacknxt; 123 int stacknleft; 124 char *sstrend; 125 126 127 static void 128 stnewblock(int nbytes) 129 { 130 struct stack_block *sp; 131 int allocsize; 132 133 if (nbytes < MINSIZE) 134 nbytes = MINSIZE; 135 136 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes); 137 138 INTOFF; 139 sp = ckmalloc(allocsize); 140 sp->prev = stackp; 141 stacknxt = SPACE(sp); 142 stacknleft = allocsize - (stacknxt - (char*)sp); 143 sstrend = stacknxt + stacknleft; 144 stackp = sp; 145 INTON; 146 } 147 148 149 pointer 150 stalloc(int nbytes) 151 { 152 char *p; 153 154 nbytes = ALIGN(nbytes); 155 if (nbytes > stacknleft) 156 stnewblock(nbytes); 157 p = stacknxt; 158 stacknxt += nbytes; 159 stacknleft -= nbytes; 160 return p; 161 } 162 163 164 void 165 stunalloc(pointer p) 166 { 167 if (p == NULL) { /*DEBUG */ 168 write(STDERR_FILENO, "stunalloc\n", 10); 169 abort(); 170 } 171 stacknleft += stacknxt - (char *)p; 172 stacknxt = p; 173 } 174 175 176 177 void 178 setstackmark(struct stackmark *mark) 179 { 180 mark->stackp = stackp; 181 mark->stacknxt = stacknxt; 182 mark->stacknleft = stacknleft; 183 /* Ensure this block stays in place. */ 184 if (stackp != NULL && stacknxt == SPACE(stackp)) 185 stalloc(1); 186 } 187 188 189 void 190 popstackmark(struct stackmark *mark) 191 { 192 struct stack_block *sp; 193 194 INTOFF; 195 while (stackp != mark->stackp) { 196 sp = stackp; 197 stackp = sp->prev; 198 ckfree(sp); 199 } 200 stacknxt = mark->stacknxt; 201 stacknleft = mark->stacknleft; 202 sstrend = stacknxt + stacknleft; 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 static void 218 growstackblock(int min) 219 { 220 char *p; 221 int newlen; 222 char *oldspace; 223 int oldlen; 224 struct stack_block *sp; 225 struct stack_block *oldstackp; 226 227 if (min < stacknleft) 228 min = stacknleft; 229 if ((unsigned int)min >= 230 INT_MAX / 2 - ALIGN(sizeof(struct stack_block))) 231 error("Out of space"); 232 min += stacknleft; 233 min += ALIGN(sizeof(struct stack_block)); 234 newlen = 512; 235 while (newlen < min) 236 newlen <<= 1; 237 oldspace = stacknxt; 238 oldlen = stacknleft; 239 240 if (stackp != NULL && stacknxt == SPACE(stackp)) { 241 INTOFF; 242 oldstackp = stackp; 243 stackp = oldstackp->prev; 244 sp = ckrealloc((pointer)oldstackp, newlen); 245 sp->prev = stackp; 246 stackp = sp; 247 stacknxt = SPACE(sp); 248 stacknleft = newlen - (stacknxt - (char*)sp); 249 sstrend = stacknxt + stacknleft; 250 INTON; 251 } else { 252 newlen -= ALIGN(sizeof(struct stack_block)); 253 p = stalloc(newlen); 254 if (oldlen != 0) 255 memcpy(p, oldspace, oldlen); 256 stunalloc(p); 257 } 258 } 259 260 261 262 /* 263 * The following routines are somewhat easier to use that the above. 264 * The user declares a variable of type STACKSTR, which may be declared 265 * to be a register. The macro STARTSTACKSTR initializes things. Then 266 * the user uses the macro STPUTC to add characters to the string. In 267 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 268 * grown as necessary. When the user is done, she can just leave the 269 * string there and refer to it using stackblock(). Or she can allocate 270 * the space for it using grabstackstr(). If it is necessary to allow 271 * someone else to use the stack temporarily and then continue to grow 272 * the string, the user should use grabstack to allocate the space, and 273 * then call ungrabstr(p) to return to the previous mode of operation. 274 * 275 * USTPUTC is like STPUTC except that it doesn't check for overflow. 276 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 277 * is space for at least one character. 278 */ 279 280 static char * 281 growstrstackblock(int n, int min) 282 { 283 growstackblock(min); 284 return stackblock() + n; 285 } 286 287 char * 288 growstackstr(void) 289 { 290 int len; 291 292 len = stackblocksize(); 293 return (growstrstackblock(len, 0)); 294 } 295 296 297 /* 298 * Called from CHECKSTRSPACE. 299 */ 300 301 char * 302 makestrspace(int min, char *p) 303 { 304 int len; 305 306 len = p - stackblock(); 307 return (growstrstackblock(len, min)); 308 } 309 310 311 char * 312 stputbin(const char *data, size_t len, char *p) 313 { 314 CHECKSTRSPACE(len, p); 315 memcpy(p, data, len); 316 return (p + len); 317 } 318 319 char * 320 stputs(const char *data, char *p) 321 { 322 return (stputbin(data, strlen(data), p)); 323 } 324