xref: /openbsd-current/libexec/ld.so/util.c

/*	$OpenBSD: util.c,v 1.7 2002/07/24 00:13:55 deraadt Exp $	*/

/*
 * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed under OpenBSD by
 *	Per Fogelstrom, Opsycon AB, Sweden.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <sys/types.h>
#include <sys/mman.h>
#include <string.h>
#include "archdep.h"

/*
 * Static vars usable after bootstrapping.
 */
static void *_dl_malloc_base;
static void *_dl_malloc_pool = 0;
static long *_dl_malloc_free = 0;

char *
_dl_strdup(const char *orig)
{
	char *newstr;
	int len;

	len = _dl_strlen(orig)+1;
	newstr = _dl_malloc(len);
	_dl_strlcpy(newstr, orig, len);
	return (newstr);
}

/*
 *  The following malloc/free code is a very simplified implementation
 *  of a malloc function. However, we do not need to be very complex here
 *  because we only free memory when 'dlclose()' is called and we can
 *  reuse at least the memory allocated for the object descriptor. We have
 *  one dynamic string allocated, the library name and it is likely that
 *  we can reuse that one to without a lot of complex colapsing code.
 */

void *
_dl_malloc(size_t size)
{
	long *p, *t, *n;

	size = (size + 8 + DL_MALLOC_ALIGN - 1) & ~(DL_MALLOC_ALIGN - 1);

	if ((t = _dl_malloc_free) != 0) {	/* Try free list first */
		n = (long *)&_dl_malloc_free;
		while (t && t[-1] < size) {
			n = t;
			t = (long *)*t;
		}
		if (t) {
			*n = *t;
			_dl_memset(t, 0, t[-1] - 4);
			return((void *)t);
		}
	}
	if (_dl_malloc_pool == 0 ||
	    _dl_malloc_pool + size > _dl_malloc_base + 4096) {
		_dl_malloc_pool = (void *)_dl_mmap((void *)0, 4096,
		    PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
		if (_dl_malloc_pool == 0 || _dl_malloc_pool == MAP_FAILED ) {
			_dl_printf("Dynamic loader failure: malloc.\n");
			_dl_exit(7);
		}
		_dl_malloc_base = _dl_malloc_pool;
	}
	p = _dl_malloc_pool;
	_dl_malloc_pool += size;
	_dl_memset(p, 0, size);
	*p = size;
	return((void *)(p + 1));
}

void
_dl_free(void *p)
{
	long *t = (long *)p;

	*t = (long)_dl_malloc_free;
	_dl_malloc_free = p;
}