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/* $NetBSD: dlfcn_elf.c,v 1.13 2012/06/24 15:26:03 christos 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 1.13 2012/06/24 15:26:03 christos Exp $");
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/atomic.h>
#include <assert.h>
#include <elf.h>
#include <errno.h>
#include <string.h>
#include <stdbool.h>
#undef dlopen
#undef dlclose
#undef dlsym
#undef dlerror
#undef dladdr
#undef dfinfo
#define dlopen ___dlopen
#define dlclose ___dlclose
#define dlsym ___dlsym
#define dlvsym ___dlvsym
#define dlerror ___dlerror
#define dladdr ___dladdr
#define dlinfo ___dlinfo
#define dl_iterate_phdr ___dl_iterate_phdr
#define ELFSIZE ARCH_ELFSIZE
#include "rtld.h"
#ifdef __weak_alias
__weak_alias(dlopen,___dlopen)
__weak_alias(dlclose,___dlclose)
__weak_alias(dlsym,___dlsym)
__weak_alias(dlvsym,___dlvsym)
__weak_alias(dlerror,___dlerror)
__weak_alias(dladdr,___dladdr)
__weak_alias(dlinfo,___dlinfo)
__weak_alias(dl_iterate_phdr,___dl_iterate_phdr)
__weak_alias(__dlopen,___dlopen)
__weak_alias(__dlclose,___dlclose)
__weak_alias(__dlsym,___dlsym)
__weak_alias(__dlvsym,___dlvsym)
__weak_alias(__dlerror,___dlerror)
__weak_alias(__dladdr,___dladdr)
__weak_alias(__dlinfo,___dlinfo)
__weak_alias(__dl_iterate_phdr,___dl_iterate_phdr)
#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*/
void *
dlvsym(void *handle, const char *name, const char *version)
{
return NULL;
}
/*ARGSUSED*/
__aconst char *
dlerror(void)
{
return dlfcn_error;
}
/*ARGSUSED*/
int
dladdr(const void *addr, Dl_info *dli)
{
return 0;
}
/*ARGSUSED*/
int
dlinfo(void *handle, int req, void *v)
{
return -1;
}
static const char *dlpi_name;
static Elf_Addr dlpi_addr;
static const Elf_Phdr *dlpi_phdr;
static Elf_Half dlpi_phnum;
static void
dl_iterate_phdr_setup(void)
{
const AuxInfo *aux;
_DIAGASSERT(_dlauxinfo() != NULL);
for (aux = _dlauxinfo(); aux->a_type != AT_NULL; ++aux) {
switch (aux->a_type) {
case AT_BASE:
dlpi_addr = aux->a_v;
break;
case AT_PHDR:
dlpi_phdr = (void *)aux->a_v;
break;
case AT_PHNUM:
_DIAGASSERT(__type_fit(Elf_Half, aux->a_v));
dlpi_phnum = (Elf_Half)aux->a_v;
break;
case AT_SUN_EXECNAME:
dlpi_name = (void *)aux->a_v;
break;
}
}
}
/*ARGSUSED*/
int
dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *),
void *data)
{
static bool setup_done;
struct dl_phdr_info phdr_info;
if (!setup_done) {
/*
* This can race on the first call to dl_iterate_phdr.
* dl_iterate_phdr_setup only touches field of pointer size
* and smaller and such stores are atomic.
*/
dl_iterate_phdr_setup();
#if !defined(__minix)
membar_producer();
#endif /* !defined(__minix) */
setup_done = true;
}
memset(&phdr_info, 0, sizeof(phdr_info));
phdr_info.dlpi_addr = dlpi_addr;
phdr_info.dlpi_phdr = dlpi_phdr;
phdr_info.dlpi_phnum = dlpi_phnum;
phdr_info.dlpi_name = dlpi_name;
return callback(&phdr_info, sizeof(phdr_info), data);
}
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