glibc/elf/dl-libc.c

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/* Handle loading and unloading shared objects for internal libc purposes.
Copyright (C) 1999, 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Zack Weinberg <zack@rabi.columbia.edu>, 1999.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <dlfcn.h>
#include <stdlib.h>
#include <ldsodefs.h>
/* The purpose of this file is to provide wrappers around the dynamic
linker error mechanism (similar to dlopen() et al in libdl) which
are usable from within libc. Generally we want to throw away the
string that dlerror() would return and just pass back a null pointer
for errors. This also lets the rest of libc not know about the error
handling mechanism.
Much of this code came from gconv_dl.c with slight modifications. */
static int
internal_function
dlerror_run (void (*operate) (void *), void *args)
{
const char *objname;
const char *last_errstring = NULL;
int result;
(void) _dl_catch_error (&objname, &last_errstring, operate, args);
result = last_errstring != NULL;
if (result && last_errstring != _dl_out_of_memory)
free ((char *) last_errstring);
return result;
}
/* These functions are called by dlerror_run... */
struct do_dlopen_args
{
/* Argument to do_dlopen. */
const char *name;
/* Return from do_dlopen. */
struct link_map *map;
};
struct do_dlsym_args
{
/* Arguments to do_dlsym. */
struct link_map *map;
const char *name;
/* Return values of do_dlsym. */
Update. 2000-05-05 Ulrich Drepper <drepper@redhat.com> * elf/dl-load.c (_dl_map_object_from_fd): Little of computation of parameter to mprotect and for variable assignments. 2000-05-03 Jes Sorensen <jes@linuxcare.com> * sysdeps/generic/ldsodefs.h (LOOKUP_VALUE_ADDRESS): Check the validity of map before dereferencing it. * elf/dl-reloc.c (RESOLVE_MAP): Define. 2000-05-02 Jes Sorensen <jes@linuxcare.com> * elf/dl-runtime.c (fixup): Add the value returned in the symbol lookup to the arguments to elf_machine_fixup_plt(). * sysdeps/ia64/dl-machine.h (elf_machine_fixup_plt): Add Link_map of the symbol being resolved to input argument list and make the function return the pointer to the reloc. * sysdeps/alpha/dl-machine.h (elf_machine_fixup_plt): Change return valuie to lookup_t and return the value. * sysdeps/arm/dl-machine.h (elf_machine_fixup_plt): Likewise. * sysdeps/generic/dl-machine.h (elf_machine_fixup_plt): Likewise. * sysdeps/i386/dl-machine.h (elf_machine_fixup_plt): Likewise. * sysdeps/m68k/dl-machine.h (elf_machine_fixup_plt): Likewise. * sysdeps/sparc/sparc32/dl-machine.h (elf_machine_fixup_plt): Likewise. * sysdeps/sparc/sparc64/dl-machine.h (elf_machine_fixup_plt): Likewise. * sysdeps/powerpc/dl-machine.h (elf_machine_fixup_plt): Likewise. Make it an inline function returning value after calling __elf_machine_fixup_plt(). * elf/dl-sym.c (_dl_vsym): Use DL_SYMBOL_ADDRESS() to obtain the symbol address. * elf/dl-symbol.c (_dl_symbol_value): Use LOOKUP_VALUE_ADDRESS to obtain the symbol address. * sysdeps/generic/ldsodefs.h: Add generic DL_SYMBOL_ADDRESS() macro depending on the definition of ELF_FUNCTION_PTR_IS_SPECIAL. * sysdeps/ia64/dl-machine.h: Add DL_SYMBOL_ADDRESS() macro calling _dl_symbol_address() - this way DL_SYMBOL_ADDRESS() turns into an inline on non ia64. 2000-04-28 Jes Sorensen <jes@linuxcare.com> * elf/dl-runtime.c (fixup): Use the portable macros to get the symbol address of an object. * elf/dl-runtime.c (fixup-profile): Use the portable macros to get the symbol address of an object. * elf/dl-libc.c (struct do_dlsym_args): Change loadbase to a lookup_t. * elf/dl-lookup.c (_dl_lookup_symbol): Likewise. (_dl_lookup_symbol_skip): Likewise. (_dl_lookup_versioned_symbol): Likewise. (_dl_lookup_versioned_symbol_skip): Likewise. 2000-04-27 Jes Sorensen <jes@linuxcare.com> * elf/rtld.c (_dl_start): Get the function pointer return address via _dl_start_address for architectures that need a function pointer descriptor rather than just a pointer (ia64). * sysdeps/generic/dl-lookupcfg.h: New file. * sysdeps/ia64/dl-lookupcfg.h: New file. * sysdeps/ia64/dl-machine.h: New file. * sysdeps/ia64/dl-symaddr.c: New file. * sysdeps/ia64/dl-fptr.c: New file. * elf/elf.h: Add IA-64 specific definitions.
2000-05-05 07:15:29 +00:00
lookup_t loadbase;
const ElfW(Sym) *ref;
};
static void
do_dlopen (void *ptr)
{
struct do_dlopen_args *args = (struct do_dlopen_args *) ptr;
/* Open and relocate the shared object. */
args->map = _dl_open (args->name, RTLD_LAZY, NULL);
}
static void
do_dlsym (void *ptr)
{
struct do_dlsym_args *args = (struct do_dlsym_args *) ptr;
args->ref = NULL;
args->loadbase = _dl_lookup_symbol (args->name, args->map, &args->ref,
args->map->l_local_scope, 0);
}
static void
do_dlclose (void *ptr)
{
_dl_close ((struct link_map *) ptr);
}
/* ... and these functions call dlerror_run. */
void *
__libc_dlopen (const char *__name)
{
struct do_dlopen_args args;
args.name = __name;
return (dlerror_run (do_dlopen, &args) ? NULL : (void *) args.map);
}
void *
__libc_dlsym (void *__map, const char *__name)
{
struct do_dlsym_args args;
args.map = __map;
args.name = __name;
return (dlerror_run (do_dlsym, &args) ? NULL
: (void *) (DL_SYMBOL_ADDRESS (args.loadbase, args.ref)));
}
int
__libc_dlclose (void *__map)
{
return dlerror_run (do_dlclose, __map);
}