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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95"; 40 #endif 41 #endif /* not lint */ 42 #include <sys/cdefs.h> 43 __FBSDID("$FreeBSD$"); 44 45 #include <sys/param.h> 46 #include "shell.h" 47 #include "output.h" 48 #include "memalloc.h" 49 #include "error.h" 50 #include "mystring.h" 51 #include "expand.h" 52 #include <stdlib.h> 53 #include <unistd.h> 54 55 /* 56 * Like malloc, but returns an error when out of space. 57 */ 58 59 pointer 60 ckmalloc(int nbytes) 61 { 62 pointer p; 63 64 if ((p = malloc(nbytes)) == 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 if ((p = realloc(p, nbytes)) == NULL) 78 error("Out of space"); 79 return p; 80 } 81 82 83 /* 84 * Make a copy of a string in safe storage. 85 */ 86 87 char * 88 savestr(char *s) 89 { 90 char *p; 91 92 p = ckmalloc(strlen(s) + 1); 93 scopy(s, p); 94 return p; 95 } 96 97 98 /* 99 * Parse trees for commands are allocated in lifo order, so we use a stack 100 * to make this more efficient, and also to avoid all sorts of exception 101 * handling code to handle interrupts in the middle of a parse. 102 * 103 * The size 496 was chosen because with 16-byte alignment the total size 104 * for the allocated block is 512. 105 */ 106 107 #define MINSIZE 496 /* minimum size of a block. */ 108 109 110 struct stack_block { 111 struct stack_block *prev; 112 /* Data follows */ 113 }; 114 #define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block))) 115 116 STATIC struct stack_block *stackp; 117 STATIC struct stackmark *markp; 118 char *stacknxt; 119 int stacknleft; 120 int sstrnleft; 121 int herefd = -1; 122 123 124 static void 125 stnewblock(int nbytes) 126 { 127 struct stack_block *sp; 128 int allocsize; 129 130 if (nbytes < MINSIZE) 131 nbytes = MINSIZE; 132 133 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes); 134 135 INTOFF; 136 sp = ckmalloc(allocsize); 137 sp->prev = stackp; 138 stacknxt = SPACE(sp); 139 stacknleft = allocsize - (stacknxt - (char*)sp); 140 stackp = sp; 141 INTON; 142 } 143 144 145 pointer 146 stalloc(int nbytes) 147 { 148 char *p; 149 150 nbytes = ALIGN(nbytes); 151 if (nbytes > stacknleft) 152 stnewblock(nbytes); 153 p = stacknxt; 154 stacknxt += nbytes; 155 stacknleft -= nbytes; 156 return p; 157 } 158 159 160 void 161 stunalloc(pointer p) 162 { 163 if (p == NULL) { /*DEBUG */ 164 write(STDERR_FILENO, "stunalloc\n", 10); 165 abort(); 166 } 167 stacknleft += stacknxt - (char *)p; 168 stacknxt = p; 169 } 170 171 172 173 void 174 setstackmark(struct stackmark *mark) 175 { 176 mark->stackp = stackp; 177 mark->stacknxt = stacknxt; 178 mark->stacknleft = stacknleft; 179 mark->marknext = markp; 180 markp = mark; 181 } 182 183 184 void 185 popstackmark(struct stackmark *mark) 186 { 187 struct stack_block *sp; 188 189 INTOFF; 190 markp = mark->marknext; 191 while (stackp != mark->stackp) { 192 sp = stackp; 193 stackp = sp->prev; 194 ckfree(sp); 195 } 196 stacknxt = mark->stacknxt; 197 stacknleft = mark->stacknleft; 198 INTON; 199 } 200 201 202 /* 203 * When the parser reads in a string, it wants to stick the string on the 204 * stack and only adjust the stack pointer when it knows how big the 205 * string is. Stackblock (defined in stack.h) returns a pointer to a block 206 * of space on top of the stack and stackblocklen returns the length of 207 * this block. Growstackblock will grow this space by at least one byte, 208 * possibly moving it (like realloc). Grabstackblock actually allocates the 209 * part of the block that has been used. 210 */ 211 212 void 213 growstackblock(void) 214 { 215 char *p; 216 int newlen; 217 char *oldspace; 218 int oldlen; 219 struct stack_block *sp; 220 struct stack_block *oldstackp; 221 struct stackmark *xmark; 222 223 newlen = (stacknleft == 0) ? MINSIZE : stacknleft * 2 + 100; 224 newlen = ALIGN(newlen); 225 oldspace = stacknxt; 226 oldlen = stacknleft; 227 228 if (stackp != NULL && stacknxt == SPACE(stackp)) { 229 INTOFF; 230 oldstackp = stackp; 231 stackp = oldstackp->prev; 232 sp = ckrealloc((pointer)oldstackp, newlen); 233 sp->prev = stackp; 234 stackp = sp; 235 stacknxt = SPACE(sp); 236 stacknleft = newlen - (stacknxt - (char*)sp); 237 238 /* 239 * Stack marks pointing to the start of the old block 240 * must be relocated to point to the new block 241 */ 242 xmark = markp; 243 while (xmark != NULL && xmark->stackp == oldstackp) { 244 xmark->stackp = stackp; 245 xmark->stacknxt = stacknxt; 246 xmark->stacknleft = stacknleft; 247 xmark = xmark->marknext; 248 } 249 INTON; 250 } else { 251 p = stalloc(newlen); 252 if (oldlen != 0) 253 memcpy(p, oldspace, oldlen); 254 stunalloc(p); 255 } 256 } 257 258 259 260 void 261 grabstackblock(int len) 262 { 263 len = ALIGN(len); 264 stacknxt += len; 265 stacknleft -= len; 266 } 267 268 269 270 /* 271 * The following routines are somewhat easier to use that the above. 272 * The user declares a variable of type STACKSTR, which may be declared 273 * to be a register. The macro STARTSTACKSTR initializes things. Then 274 * the user uses the macro STPUTC to add characters to the string. In 275 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is 276 * grown as necessary. When the user is done, she can just leave the 277 * string there and refer to it using stackblock(). Or she can allocate 278 * the space for it using grabstackstr(). If it is necessary to allow 279 * someone else to use the stack temporarily and then continue to grow 280 * the string, the user should use grabstack to allocate the space, and 281 * then call ungrabstr(p) to return to the previous mode of operation. 282 * 283 * USTPUTC is like STPUTC except that it doesn't check for overflow. 284 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there 285 * is space for at least one character. 286 */ 287 288 289 char * 290 growstackstr(void) 291 { 292 int len; 293 294 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 /* 307 * Called from CHECKSTRSPACE. 308 */ 309 310 char * 311 makestrspace(void) 312 { 313 int len; 314 315 len = stackblocksize() - sstrnleft; 316 growstackblock(); 317 sstrnleft = stackblocksize() - len; 318 return stackblock() + len; 319 } 320 321 322 323 void 324 ungrabstackstr(char *s, char *p) 325 { 326 stacknleft += stacknxt - s; 327 stacknxt = s; 328 sstrnleft = stacknleft - (p - s); 329 } 330