util.c revision 1.1 
1/*	$OpenBSD: util.c,v 1.1 2002/02/21 23:17:53 drahn Exp $	*/
2
3#include <sys/types.h>
4#include <sys/mman.h>
5#include <string.h>
6#include "archdep.h"
7
8/*
9 * Static vars usable after bootsrapping.
10 */
11static void *_dl_malloc_base;
12static void *_dl_malloc_pool = 0;
13static long *_dl_malloc_free = 0;
14
15char *
16_dl_strdup(const char *orig)
17{
18	char *newstr;
19	newstr = _dl_malloc(_dl_strlen(orig)+1);
20	_dl_strcpy(newstr, orig);
21	return (newstr);
22}
23
24/*
25 *  The following malloc/free code is a very simplified implementation
26 *  of a malloc function. However, we do not need to be very complex here
27 *  because we only free memory when 'dlclose()' is called and we can
28 *  reuse at least the memory allocated for the object descriptor. We have
29 *  one dynamic string allocated, the library name and it is likely that
30 *  we can reuse that one to without a lot of complex colapsing code.
31 */
32
33void *
34_dl_malloc(int size)
35{
36	long *p;
37	long *t, *n;
38
39	size = (size + 8 + DL_MALLOC_ALIGN - 1) & ~(DL_MALLOC_ALIGN - 1);
40
41	if ((t = _dl_malloc_free) != 0) {	/* Try free list first */
42		n = (long *)&_dl_malloc_free;
43		while (t && t[-1] < size) {
44			n = t;
45			t = (long *)*t;
46		}
47		if (t) {
48			*n = *t;
49			_dl_memset(t, 0, t[-1] - 4);
50			return((void *)t);
51		}
52	}
53	if ((_dl_malloc_pool == 0) ||
54	    (_dl_malloc_pool + size > _dl_malloc_base + 4096)) {
55		_dl_malloc_pool = (void *)_dl_mmap((void *)0, 4096,
56						PROT_READ|PROT_WRITE,
57						MAP_ANON|MAP_PRIVATE, -1, 0);
58		if (_dl_malloc_pool == 0 || _dl_malloc_pool == MAP_FAILED ) {
59			_dl_printf("Dynamic loader failure: malloc.\n");
60			_dl_exit(7);
61		}
62		_dl_malloc_base = _dl_malloc_pool;
63	}
64	p = _dl_malloc_pool;
65	_dl_malloc_pool += size;
66	_dl_memset(p, 0, size);
67	*p = size;
68	return((void *)(p + 1));
69}
70
71void
72_dl_free(void *p)
73{
74	long *t = (long *)p;
75
76	*t = (long)_dl_malloc_free;
77	_dl_malloc_free = p;
78}
79