1/*	$NetBSD: memalloc.c,v 1.28 2003/08/07 09:05:34 agc Exp $	*/
2
3/*-
4 * Copyright (c) 1991, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Kenneth Almquist.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include <sys/cdefs.h>
36#ifndef lint
37#if 0
38static char sccsid[] = "@(#)memalloc.c	8.3 (Berkeley) 5/4/95";
39#else
40__RCSID("$NetBSD: memalloc.c,v 1.28 2003/08/07 09:05:34 agc Exp $");
41#endif
42#endif /* not lint */
43
44#include <stdlib.h>
45#include <unistd.h>
46
47#include "shell.h"
48#include "output.h"
49#include "memalloc.h"
50#include "error.h"
51#include "machdep.h"
52#include "mystring.h"
53
54/*
55 * Like malloc, but returns an error when out of space.
56 */
57
58pointer
59ckmalloc(int nbytes)
60{
61	pointer p;
62
63	p = malloc(nbytes);
64	if (p == NULL)
65		error("Out of space");
66	return p;
67}
68
69
70/*
71 * Same for realloc.
72 */
73
74pointer
75ckrealloc(pointer p, int nbytes)
76{
77	p = realloc(p, nbytes);
78	if (p == NULL)
79		error("Out of space");
80	return p;
81}
82
83
84/*
85 * Make a copy of a string in safe storage.
86 */
87
88char *
89savestr(const char *s)
90{
91	char *p;
92
93	p = ckmalloc(strlen(s) + 1);
94	scopy(s, p);
95	return p;
96}
97
98
99/*
100 * Parse trees for commands are allocated in lifo order, so we use a stack
101 * to make this more efficient, and also to avoid all sorts of exception
102 * handling code to handle interrupts in the middle of a parse.
103 *
104 * The size 504 was chosen because the Ultrix malloc handles that size
105 * well.
106 */
107
108#define MINSIZE 504		/* minimum size of a block */
109
110struct stack_block {
111	struct stack_block *prev;
112	char space[MINSIZE];
113};
114
115struct stack_block stackbase;
116struct stack_block *stackp = &stackbase;
117struct stackmark *markp;
118char *stacknxt = stackbase.space;
119int stacknleft = MINSIZE;
120int sstrnleft;
121int herefd = -1;
122
123pointer
124stalloc(int nbytes)
125{
126	char *p;
127
128	nbytes = SHELL_ALIGN(nbytes);
129	if (nbytes > stacknleft) {
130		int blocksize;
131		struct stack_block *sp;
132
133		blocksize = nbytes;
134		if (blocksize < MINSIZE)
135			blocksize = MINSIZE;
136		INTOFF;
137		sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize);
138		sp->prev = stackp;
139		stacknxt = sp->space;
140		stacknleft = blocksize;
141		stackp = sp;
142		INTON;
143	}
144	p = stacknxt;
145	stacknxt += nbytes;
146	stacknleft -= nbytes;
147	return p;
148}
149
150
151void
152stunalloc(pointer p)
153{
154	if (p == NULL) {		/*DEBUG */
155		write(2, "stunalloc\n", 10);
156		abort();
157	}
158	stacknleft += stacknxt - (char *)p;
159	stacknxt = p;
160}
161
162
163
164void
165setstackmark(struct stackmark *mark)
166{
167	mark->stackp = stackp;
168	mark->stacknxt = stacknxt;
169	mark->stacknleft = stacknleft;
170	mark->marknext = markp;
171	markp = mark;
172}
173
174
175void
176popstackmark(struct stackmark *mark)
177{
178	struct stack_block *sp;
179
180	INTOFF;
181	markp = mark->marknext;
182	while (stackp != mark->stackp) {
183		sp = stackp;
184		stackp = sp->prev;
185		ckfree(sp);
186	}
187	stacknxt = mark->stacknxt;
188	stacknleft = mark->stacknleft;
189	INTON;
190}
191
192
193/*
194 * When the parser reads in a string, it wants to stick the string on the
195 * stack and only adjust the stack pointer when it knows how big the
196 * string is.  Stackblock (defined in stack.h) returns a pointer to a block
197 * of space on top of the stack and stackblocklen returns the length of
198 * this block.  Growstackblock will grow this space by at least one byte,
199 * possibly moving it (like realloc).  Grabstackblock actually allocates the
200 * part of the block that has been used.
201 */
202
203void
204growstackblock(void)
205{
206	int newlen = SHELL_ALIGN(stacknleft * 2 + 100);
207
208	if (stacknxt == stackp->space && stackp != &stackbase) {
209		struct stack_block *oldstackp;
210		struct stackmark *xmark;
211		struct stack_block *sp;
212
213		INTOFF;
214		oldstackp = stackp;
215		sp = stackp;
216		stackp = sp->prev;
217		sp = ckrealloc((pointer)sp,
218		    sizeof(struct stack_block) - MINSIZE + newlen);
219		sp->prev = stackp;
220		stackp = sp;
221		stacknxt = sp->space;
222		stacknleft = newlen;
223
224		/*
225		 * Stack marks pointing to the start of the old block
226		 * must be relocated to point to the new block
227		 */
228		xmark = markp;
229		while (xmark != NULL && xmark->stackp == oldstackp) {
230			xmark->stackp = stackp;
231			xmark->stacknxt = stacknxt;
232			xmark->stacknleft = stacknleft;
233			xmark = xmark->marknext;
234		}
235		INTON;
236	} else {
237		char *oldspace = stacknxt;
238		int oldlen = stacknleft;
239		char *p = stalloc(newlen);
240
241		(void)memcpy(p, oldspace, oldlen);
242		stacknxt = p;			/* free the space */
243		stacknleft += newlen;		/* we just allocated */
244	}
245}
246
247void
248grabstackblock(int len)
249{
250	len = SHELL_ALIGN(len);
251	stacknxt += len;
252	stacknleft -= len;
253}
254
255/*
256 * The following routines are somewhat easier to use than the above.
257 * The user declares a variable of type STACKSTR, which may be declared
258 * to be a register.  The macro STARTSTACKSTR initializes things.  Then
259 * the user uses the macro STPUTC to add characters to the string.  In
260 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
261 * grown as necessary.  When the user is done, she can just leave the
262 * string there and refer to it using stackblock().  Or she can allocate
263 * the space for it using grabstackstr().  If it is necessary to allow
264 * someone else to use the stack temporarily and then continue to grow
265 * the string, the user should use grabstack to allocate the space, and
266 * then call ungrabstr(p) to return to the previous mode of operation.
267 *
268 * USTPUTC is like STPUTC except that it doesn't check for overflow.
269 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
270 * is space for at least one character.
271 */
272
273char *
274growstackstr(void)
275{
276	int len = stackblocksize();
277	if (herefd >= 0 && len >= 1024) {
278		xwrite(herefd, stackblock(), len);
279		sstrnleft = len - 1;
280		return stackblock();
281	}
282	growstackblock();
283	sstrnleft = stackblocksize() - len - 1;
284	return stackblock() + len;
285}
286
287/*
288 * Called from CHECKSTRSPACE.
289 */
290
291char *
292makestrspace(void)
293{
294	int len = stackblocksize() - sstrnleft;
295	growstackblock();
296	sstrnleft = stackblocksize() - len;
297	return stackblock() + len;
298}
299
300void
301ungrabstackstr(char *s, char *p)
302{
303	stacknleft += stacknxt - s;
304	stacknxt = s;
305	sstrnleft = stacknleft - (p - s);
306
307}
308