NetBSD/lib/libc/dlfcn/dlfcn_elf.c
skrll d900731978 Resolve dlsym(3) and friends directly so that dlsym(RTLD_NEXT,...) works.
Previously dlsym resolved to the version in crt0.o or libc which would
mean that the caller's shared object couldn't be determined correctly
using __builtin_return_address(0).

Mainly from FreeBSD, but adapted by me. Benefits of this solutions are:

	- backward comptibility maintained
	- existing broken binaries are fixed with a new ld.elf_so
	- __mainprog_obj can be removed from crt0.o
	- we do the same thing as FreeBSD

Fixes PR 22067.

OKed by Jason and Christos.
2003-08-12 09:18:38 +00:00

97 lines
2.6 KiB
C

/* $NetBSD: dlfcn_elf.c,v 1.4 2003/08/12 09:18:43 skrll Exp $ */
/*
* Copyright (c) 2000 Takuya SHIOZAKI
* All rights reserved.
*
* 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.
*
* 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/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: dlfcn_elf.c,v 1.4 2003/08/12 09:18:43 skrll Exp $");
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#define ELFSIZE ARCH_ELFSIZE
#include "rtld.h"
#ifdef __weak_alias
__weak_alias(dlopen,__dlopen)
__weak_alias(dlclose,__dlclose)
__weak_alias(dlsym,__dlsym)
__weak_alias(dlerror,__dlerror)
__weak_alias(dladdr,__dladdr)
#endif
/*
* For ELF, the dynamic linker directly resolves references to its
* services to functions inside the dynamic linker itself. These
* weak-symbol stubs are necessary so that "ld" won't complain about
* undefined symbols. The stubs are executed only when the program is
* linked statically, or when a given service isn't implemented in the
* dynamic linker. They must return an error if called, and they must
* be weak symbols so that the dynamic linker can override them.
*/
static char dlfcn_error[] = "Service unavailable";
/*ARGSUSED*/
void *
dlopen(const char *name, int mode)
{
return NULL;
}
/*ARGSUSED*/
int
dlclose(void *fd)
{
return -1;
}
/*ARGSUSED*/
void *
dlsym(void *handle, const char *name)
{
return NULL;
}
/*ARGSUSED*/
__aconst char *
dlerror()
{
return dlfcn_error;
}
/*ARGSUSED*/
int
dladdr(const void *addr, Dl_info *dli)
{
return 0;
}