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 35 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95"; 36 #endif 37 #endif /* not lint */ 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 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 55 pointer 56 ckmalloc(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 73 pointer 74 ckrealloc(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 84 void 85 ckfree(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 97 char * 98 savestr(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. */ 118 119 120 struct stack_block { 121 struct stack_block *prev; 122 /* Data follows */ 123 }; 124 #define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block))) 125 126 static struct stack_block *stackp; 127 char *stacknxt; 128 int stacknleft; 129 char *sstrend; 130 131 132 static void 133 stnewblock(int nbytes) 134 { 135 struct stack_block *sp; 136 int allocsize; 137 138 if (nbytes < MINSIZE) 139 nbytes = MINSIZE; 140 141 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes); 142 143 INTOFF; 144 sp = ckmalloc(allocsize); 145 sp->prev = stackp; 146 stacknxt = SPACE(sp); 147 stacknleft = allocsize - (stacknxt - (char*)sp); 148 sstrend = stacknxt + stacknleft; 149 stackp = sp; 150 INTON; 151 } 152 153 154 pointer 155 stalloc(int nbytes) 156 { 157 char *p; 158 159 nbytes = ALIGN(nbytes); 160 if (nbytes > stacknleft) 161 stnewblock(nbytes); 162 p = stacknxt; 163 stacknxt += nbytes; 164 stacknleft -= nbytes; 165 return p; 166 } 167 168 169 void 170 stunalloc(pointer p) 171 { 172 if (p == NULL) { /*DEBUG */ 173 write(STDERR_FILENO, "stunalloc\n", 10); 174 abort(); 175 } 176 stacknleft += stacknxt - (char *)p; 177 stacknxt = p; 178 } 179 180 181 182 void 183 setstackmark(struct stackmark *mark) 184 { 185 mark->stackp = stackp; 186 mark->stacknxt = stacknxt; 187 mark->stacknleft = stacknleft; 188 /* Ensure this block stays in place. */ 189 if (stackp != NULL && stacknxt == SPACE(stackp)) 190 stalloc(1); 191 } 192 193 194 void 195 popstackmark(struct stackmark *mark) 196 { 197 struct stack_block *sp; 198 199 INTOFF; 200 while (stackp != mark->stackp) { 201 sp = stackp; 202 stackp = sp->prev; 203 ckfree(sp); 204 } 205 stacknxt = mark->stacknxt; 206 stacknleft = mark->stacknleft; 207 sstrend = stacknxt + stacknleft; 208 INTON; 209 } 210 211 212 /* 213 * When the parser reads in a string, it wants to stick the string on the 214 * stack and only adjust the stack pointer when it knows how big the 215 * string is. Stackblock (defined in stack.h) returns a pointer to a block 216 * of space on top of the stack and stackblocklen returns the length of 217 * this block. Growstackblock will grow this space by at least one byte, 218 * possibly moving it (like realloc). Grabstackblock actually allocates the 219 * part of the block that has been used. 220 */ 221 222 static void 223 growstackblock(int min) 224 { 225 char *p; 226 int newlen; 227 char *oldspace; 228 int oldlen; 229 struct stack_block *sp; 230 struct stack_block *oldstackp; 231 232 if (min < stacknleft) 233 min = stacknleft; 234 if ((unsigned int)min >= 235 INT_MAX / 2 - ALIGN(sizeof(struct stack_block))) 236 error("Out of space"); 237 min += stacknleft; 238 min += ALIGN(sizeof(struct stack_block)); 239 newlen = 512; 240 while (newlen < min) 241 newlen <<= 1; 242 oldspace = stacknxt; 243 oldlen = stacknleft; 244 245 if (stackp != NULL && stacknxt == SPACE(stackp)) { 246 INTOFF; 247 oldstackp = stackp; 248 stackp = oldstackp->prev; 249 sp = ckrealloc((pointer)oldstackp, newlen); 250 sp->prev = stackp; 251 stackp = sp; 252 stacknxt = SPACE(sp); 253 stacknleft = newlen - (stacknxt - (char*)sp); 254 sstrend = stacknxt + stacknleft; 255 INTON; 256 } else { 257 newlen -= ALIGN(sizeof(struct stack_block)); 258 p = stalloc(newlen); 259 if (oldlen != 0) 260 memcpy(p, oldspace, oldlen); 261 stunalloc(p); 262 } 263 } 264 265 266 267 /* 268 * The following routines are somewhat easier to use that the above. 269 * The user declares a variable of type STACKSTR, which may be declared 270 * to be a register. The macro STARTSTACKSTR initializes things. Then 271 * the user uses the macro STPUTC to add characters to the string. In 272 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 273 * grown as necessary. When the user is done, she can just leave the 274 * string there and refer to it using stackblock(). Or she can allocate 275 * the space for it using grabstackstr(). If it is necessary to allow 276 * someone else to use the stack temporarily and then continue to grow 277 * the string, the user should use grabstack to allocate the space, and 278 * then call ungrabstr(p) to return to the previous mode of operation. 279 * 280 * USTPUTC is like STPUTC except that it doesn't check for overflow. 281 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 282 * is space for at least one character. 283 */ 284 285 static char * 286 growstrstackblock(int n, int min) 287 { 288 growstackblock(min); 289 return stackblock() + n; 290 } 291 292 char * 293 growstackstr(void) 294 { 295 int len; 296 297 len = stackblocksize(); 298 return (growstrstackblock(len, 0)); 299 } 300 301 302 /* 303 * Called from CHECKSTRSPACE. 304 */ 305 306 char * 307 makestrspace(int min, char *p) 308 { 309 int len; 310 311 len = p - stackblock(); 312 return (growstrstackblock(len, min)); 313 } 314 315 316 char * 317 stputbin(const char *data, size_t len, char *p) 318 { 319 CHECKSTRSPACE(len, p); 320 memcpy(p, data, len); 321 return (p + len); 322 } 323 324 char * 325 stputs(const char *data, char *p) 326 { 327 return (stputbin(data, strlen(data), p)); 328 } 329