freebsd-dev/lib/libc/gen/dlfcn.c

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/*-
* Copyright (c) 1998 John D. Polstra
* 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*/
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#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Linkage to services provided by the dynamic linker.
*/
#include <sys/mman.h>
#include <dlfcn.h>
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#include <link.h>
#include <stddef.h>
#include "namespace.h"
#include <pthread.h>
#include "un-namespace.h"
#include "libc_private.h"
static char sorry[] = "Service unavailable";
/*
* 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.
*/
#pragma weak _rtld_error
void
_rtld_error(const char *fmt, ...)
{
}
#pragma weak dladdr
int
dladdr(const void *addr, Dl_info *dlip)
{
_rtld_error(sorry);
return 0;
}
#pragma weak dlclose
int
dlclose(void *handle)
{
_rtld_error(sorry);
return -1;
}
#pragma weak dlerror
char *
dlerror(void)
{
return sorry;
}
#pragma weak dllockinit
void
dllockinit(void *context,
void *(*lock_create)(void *context),
void (*rlock_acquire)(void *lock),
void (*wlock_acquire)(void *lock),
void (*lock_release)(void *lock),
void (*lock_destroy)(void *lock),
void (*context_destroy)(void *context))
{
if (context_destroy != NULL)
context_destroy(context);
}
#pragma weak dlopen
void *
dlopen(const char *name, int mode)
{
_rtld_error(sorry);
return NULL;
}
#pragma weak dlsym
void *
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dlsym(void * __restrict handle, const char * __restrict name)
{
_rtld_error(sorry);
return NULL;
}
#pragma weak dlfunc
dlfunc_t
dlfunc(void * __restrict handle, const char * __restrict name)
{
_rtld_error(sorry);
return NULL;
}
#pragma weak dlvsym
void *
dlvsym(void * __restrict handle, const char * __restrict name,
const char * __restrict version)
{
_rtld_error(sorry);
return NULL;
}
#pragma weak dlinfo
int
dlinfo(void * __restrict handle, int request, void * __restrict p)
{
_rtld_error(sorry);
return 0;
}
#pragma weak _rtld_thread_init
void
_rtld_thread_init(void * li)
{
_rtld_error(sorry);
}
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static pthread_once_t dl_phdr_info_once = PTHREAD_ONCE_INIT;
static struct dl_phdr_info phdr_info;
static void
dl_init_phdr_info(void)
{
Elf_Auxinfo *auxp;
size_t phent;
unsigned int i;
phent = 0;
for (auxp = __elf_aux_vector; auxp->a_type != AT_NULL; auxp++) {
switch (auxp->a_type) {
case AT_BASE:
phdr_info.dlpi_addr = (Elf_Addr)auxp->a_un.a_ptr;
break;
case AT_EXECPATH:
phdr_info.dlpi_name = (const char *)auxp->a_un.a_ptr;
break;
case AT_PHDR:
phdr_info.dlpi_phdr =
(const Elf_Phdr *)auxp->a_un.a_ptr;
break;
case AT_PHENT:
phent = auxp->a_un.a_val;
break;
case AT_PHNUM:
phdr_info.dlpi_phnum = (Elf_Half)auxp->a_un.a_val;
break;
}
}
for (i = 0; i < phdr_info.dlpi_phnum; i++) {
if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) {
phdr_info.dlpi_tls_modid = 1;
phdr_info.dlpi_tls_data =
(void*)phdr_info.dlpi_phdr[i].p_vaddr;
}
}
phdr_info.dlpi_adds = 1;
}
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#pragma weak dl_iterate_phdr
int
dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *),
void *data)
{
__init_elf_aux_vector();
if (__elf_aux_vector == NULL)
return (1);
_once(&dl_phdr_info_once, dl_init_phdr_info);
return (callback(&phdr_info, sizeof(phdr_info), data));
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}
#pragma weak fdlopen
void *
fdlopen(int fd, int mode)
{
_rtld_error(sorry);
return NULL;
}
#pragma weak _rtld_atfork_pre
void
_rtld_atfork_pre(int *locks)
{
}
#pragma weak _rtld_atfork_post
void
_rtld_atfork_post(int *locks)
{
}
#pragma weak _rtld_addr_phdr
int
_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
{
return (0);
}
#pragma weak _rtld_get_stack_prot
int
_rtld_get_stack_prot(void)
{
return (PROT_EXEC | PROT_READ | PROT_WRITE);
}