util.c revision 1.3 
1/*	$OpenBSD: util.c,v 1.3 2002/05/24 03:44:37 deraadt Exp $	*/
2
3/*
4 * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 *    must display the following acknowledgement:
16 *	This product includes software developed under OpenBSD by
17 *	Per Fogelstrom, Opsycon AB, Sweden.
18 * 4. The name of the author may not be used to endorse or promote products
19 *    derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
22 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
23 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
25 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 */
34
35#include <sys/types.h>
36#include <sys/mman.h>
37#include <string.h>
38#include "archdep.h"
39
40/*
41 * Static vars usable after bootsrapping.
42 */
43static void *_dl_malloc_base;
44static void *_dl_malloc_pool = 0;
45static long *_dl_malloc_free = 0;
46
47char *
48_dl_strdup(const char *orig)
49{
50	char *newstr;
51	newstr = _dl_malloc(_dl_strlen(orig)+1);
52	_dl_strcpy(newstr, orig);
53	return (newstr);
54}
55
56/*
57 *  The following malloc/free code is a very simplified implementation
58 *  of a malloc function. However, we do not need to be very complex here
59 *  because we only free memory when 'dlclose()' is called and we can
60 *  reuse at least the memory allocated for the object descriptor. We have
61 *  one dynamic string allocated, the library name and it is likely that
62 *  we can reuse that one to without a lot of complex colapsing code.
63 */
64
65void *
66_dl_malloc(int size)
67{
68	long *p;
69	long *t, *n;
70
71	size = (size + 8 + DL_MALLOC_ALIGN - 1) & ~(DL_MALLOC_ALIGN - 1);
72
73	if ((t = _dl_malloc_free) != 0) {	/* Try free list first */
74		n = (long *)&_dl_malloc_free;
75		while (t && t[-1] < size) {
76			n = t;
77			t = (long *)*t;
78		}
79		if (t) {
80			*n = *t;
81			_dl_memset(t, 0, t[-1] - 4);
82			return((void *)t);
83		}
84	}
85	if (_dl_malloc_pool == 0 ||
86	    _dl_malloc_pool + size > _dl_malloc_base + 4096) {
87		_dl_malloc_pool = (void *)_dl_mmap((void *)0, 4096,
88		    PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
89		if (_dl_malloc_pool == 0 || _dl_malloc_pool == MAP_FAILED ) {
90			_dl_printf("Dynamic loader failure: malloc.\n");
91			_dl_exit(7);
92		}
93		_dl_malloc_base = _dl_malloc_pool;
94	}
95	p = _dl_malloc_pool;
96	_dl_malloc_pool += size;
97	_dl_memset(p, 0, size);
98	*p = size;
99	return((void *)(p + 1));
100}
101
102void
103_dl_free(void *p)
104{
105	long *t = (long *)p;
106
107	*t = (long)_dl_malloc_free;
108	_dl_malloc_free = p;
109}
110