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 static struct stackmark *markp; 128 char *stacknxt; 129 int stacknleft; 130 int sstrnleft; 131 132 133 static void 134 stnewblock(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 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 mark->marknext = markp; 189 markp = mark; 190 } 191 192 193 void 194 popstackmark(struct stackmark *mark) 195 { 196 struct stack_block *sp; 197 198 INTOFF; 199 markp = mark->marknext; 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 INTON; 208 } 209 210 211 /* 212 * When the parser reads in a string, it wants to stick the string on the 213 * stack and only adjust the stack pointer when it knows how big the 214 * string is. Stackblock (defined in stack.h) returns a pointer to a block 215 * of space on top of the stack and stackblocklen returns the length of 216 * this block. Growstackblock will grow this space by at least one byte, 217 * possibly moving it (like realloc). Grabstackblock actually allocates the 218 * part of the block that has been used. 219 */ 220 221 static void 222 growstackblock(int min) 223 { 224 char *p; 225 int newlen; 226 char *oldspace; 227 int oldlen; 228 struct stack_block *sp; 229 struct stack_block *oldstackp; 230 struct stackmark *xmark; 231 232 if (min < stacknleft) 233 min = stacknleft; 234 if (newlen >= INT_MAX / 2 - ALIGN(sizeof(struct stack_block))) 235 error("Out of space"); 236 min += stacknleft; 237 min += ALIGN(sizeof(struct stack_block)); 238 newlen = 512; 239 while (newlen < min) 240 newlen <<= 1; 241 oldspace = stacknxt; 242 oldlen = stacknleft; 243 244 if (stackp != NULL && stacknxt == SPACE(stackp)) { 245 INTOFF; 246 oldstackp = stackp; 247 stackp = oldstackp->prev; 248 sp = ckrealloc((pointer)oldstackp, newlen); 249 sp->prev = stackp; 250 stackp = sp; 251 stacknxt = SPACE(sp); 252 stacknleft = newlen - (stacknxt - (char*)sp); 253 254 /* 255 * Stack marks pointing to the start of the old block 256 * must be relocated to point to the new block 257 */ 258 xmark = markp; 259 while (xmark != NULL && xmark->stackp == oldstackp) { 260 xmark->stackp = stackp; 261 xmark->stacknxt = stacknxt; 262 xmark->stacknleft = stacknleft; 263 xmark = xmark->marknext; 264 } 265 INTON; 266 } else { 267 newlen -= ALIGN(sizeof(struct stack_block)); 268 p = stalloc(newlen); 269 if (oldlen != 0) 270 memcpy(p, oldspace, oldlen); 271 stunalloc(p); 272 } 273 } 274 275 276 277 void 278 grabstackblock(int len) 279 { 280 len = ALIGN(len); 281 stacknxt += len; 282 stacknleft -= len; 283 } 284 285 286 287 /* 288 * The following routines are somewhat easier to use that the above. 289 * The user declares a variable of type STACKSTR, which may be declared 290 * to be a register. The macro STARTSTACKSTR initializes things. Then 291 * the user uses the macro STPUTC to add characters to the string. In 292 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 293 * grown as necessary. When the user is done, she can just leave the 294 * string there and refer to it using stackblock(). Or she can allocate 295 * the space for it using grabstackstr(). If it is necessary to allow 296 * someone else to use the stack temporarily and then continue to grow 297 * the string, the user should use grabstack to allocate the space, and 298 * then call ungrabstr(p) to return to the previous mode of operation. 299 * 300 * USTPUTC is like STPUTC except that it doesn't check for overflow. 301 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 302 * is space for at least one character. 303 */ 304 305 static char * 306 growstrstackblock(int n, int min) 307 { 308 growstackblock(min); 309 sstrnleft = stackblocksize() - n; 310 return stackblock() + n; 311 } 312 313 char * 314 growstackstr(void) 315 { 316 int len; 317 318 len = stackblocksize(); 319 return (growstrstackblock(len, 0)); 320 } 321 322 323 /* 324 * Called from CHECKSTRSPACE. 325 */ 326 327 char * 328 makestrspace(int min) 329 { 330 int len; 331 332 len = stackblocksize() - sstrnleft; 333 return (growstrstackblock(len, min)); 334 } 335 336 337 338 void 339 ungrabstackstr(char *s, char *p) 340 { 341 stacknleft += stacknxt - s; 342 stacknxt = s; 343 sstrnleft = stacknleft - (p - s); 344 } 345 346 347 char * 348 stputbin(const char *data, int len, char *p) 349 { 350 CHECKSTRSPACE(len, p); 351 memcpy(p, data, len); 352 sstrnleft -= len; 353 return (p + len); 354 } 355 356 char * 357 stputs(const char *data, char *p) 358 { 359 return (stputbin(data, strlen(data), p)); 360 } 361