2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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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
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33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95";
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD: src/bin/sh/memalloc.c,v 1.15.2.2 2002/07/19 04:38:51 tjr Exp $");
56 * Like malloc, but returns an error when out of space.
64 if ((p = malloc(nbytes)) == NULL)
65 error("Out of space");
75 ckrealloc(pointer p, int nbytes)
77 if ((p = realloc(p, nbytes)) == NULL)
78 error("Out of space");
84 * Make a copy of a string in safe storage.
92 p = ckmalloc(strlen(s) + 1);
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.
103 * The size 504 was chosen because the Ultrix malloc handles that size
107 #define MINSIZE 504 /* minimum size of a block */
111 struct stack_block *prev;
115 struct stack_block stackbase;
116 struct stack_block *stackp = &stackbase;
117 struct stackmark *markp;
118 char *stacknxt = stackbase.space;
119 int stacknleft = MINSIZE;
130 nbytes = ALIGN(nbytes);
131 if (nbytes > stacknleft) {
133 struct stack_block *sp;
136 if (blocksize < MINSIZE)
139 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE +
142 stacknxt = sp->space;
143 stacknleft = blocksize;
149 stacknleft -= nbytes;
157 if (p == NULL) { /*DEBUG */
158 write(STDERR_FILENO, "stunalloc\n", 10);
161 stacknleft += stacknxt - (char *)p;
168 setstackmark(struct stackmark *mark)
170 mark->stackp = stackp;
171 mark->stacknxt = stacknxt;
172 mark->stacknleft = stacknleft;
173 mark->marknext = markp;
179 popstackmark(struct stackmark *mark)
181 struct stack_block *sp;
184 markp = mark->marknext;
185 while (stackp != mark->stackp) {
190 stacknxt = mark->stacknxt;
191 stacknleft = mark->stacknleft;
197 * When the parser reads in a string, it wants to stick the string on the
198 * stack and only adjust the stack pointer when it knows how big the
199 * string is. Stackblock (defined in stack.h) returns a pointer to a block
200 * of space on top of the stack and stackblocklen returns the length of
201 * this block. Growstackblock will grow this space by at least one byte,
202 * possibly moving it (like realloc). Grabstackblock actually allocates the
203 * part of the block that has been used.
213 struct stack_block *sp;
214 struct stack_block *oldstackp;
216 newlen = ALIGN(stacknleft * 2 + 100);
220 if (stacknxt == stackp->space && stackp != &stackbase) {
225 sp = ckrealloc((pointer)sp, sizeof(struct stack_block) -
229 stacknxt = sp->space;
232 /* Stack marks pointing to the start of the old block
233 * must be relocated to point to the new block
235 struct stackmark *xmark;
237 while (xmark != NULL && xmark->stackp == oldstackp) {
238 xmark->stackp = stackp;
239 xmark->stacknxt = stacknxt;
240 xmark->stacknleft = stacknleft;
241 xmark = xmark->marknext;
247 memcpy(p, oldspace, oldlen);
248 stacknxt = p; /* free the space */
249 stacknleft += newlen; /* we just allocated */
256 grabstackblock(int len)
266 * The following routines are somewhat easier to use that the above.
267 * The user declares a variable of type STACKSTR, which may be declared
268 * to be a register. The macro STARTSTACKSTR initializes things. Then
269 * the user uses the macro STPUTC to add characters to the string. In
270 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
271 * grown as necessary. When the user is done, she can just leave the
272 * string there and refer to it using stackblock(). Or she can allocate
273 * the space for it using grabstackstr(). If it is necessary to allow
274 * someone else to use the stack temporarily and then continue to grow
275 * the string, the user should use grabstack to allocate the space, and
276 * then call ungrabstr(p) to return to the previous mode of operation.
278 * USTPUTC is like STPUTC except that it doesn't check for overflow.
279 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
280 * is space for at least one character.
289 len = stackblocksize();
290 if (herefd >= 0 && len >= 1024) {
291 xwrite(herefd, stackblock(), len);
296 sstrnleft = stackblocksize() - len - 1;
297 return stackblock() + len;
302 * Called from CHECKSTRSPACE.
310 len = stackblocksize() - sstrnleft;
312 sstrnleft = stackblocksize() - len;
313 return stackblock() + len;
319 ungrabstackstr(char *s, char *p)
321 stacknleft += stacknxt - s;
323 sstrnleft = stacknleft - (p - s);