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/* Load a shared object at runtime, relocate it, and run its initializer.
Copyright (C) 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <link.h>
#include <dlfcn.h>
#include <stdlib.h>
#include <errno.h>
extern void _dl_start (void); weak_extern (_dl_start)
extern int __libc_multiple_libcs; /* Defined in init-first.c. */
size_t _dl_global_scope_alloc;
struct link_map *
_dl_open (const char *file, int mode)
{
struct link_map *new, *l;
ElfW(Addr) init;
struct r_debug *r;
/* To decide whether we are the static libc or not. We must use
this variable since gcc would otherwise optimize the test away. */
void (*dl_start_ptr) (void) = &_dl_start;
/* Load the named object. */
new = _dl_map_object (NULL, file, lt_loaded);
if (new->l_searchlist)
/* It was already open. */
return new;
/* Load that object's dependencies. */
_dl_map_object_deps (new, NULL, 0);
/* Relocate the objects loaded. We do this in reverse order so that copy
relocs of earlier objects overwrite the data written by later objects. */
l = new;
while (l->l_next)
l = l->l_next;
while (1)
{
if (! l->l_relocated)
{
/* We use an indirect call call for _dl_relocate_object because
we must avoid using the PLT in the call. If our PLT entry for
_dl_relocate_object hasn't been used yet, then the dynamic
linker fixup routine will clobber _dl_global_scope during its
work. We must be sure that nothing will require a PLT fixup
between when _dl_object_relocation_scope returns and when we
enter the dynamic linker's code (_dl_relocate_object). */
__typeof (_dl_relocate_object) *reloc = &_dl_relocate_object;
(*reloc) (l, _dl_object_relocation_scope (l),
(mode & RTLD_BINDING_MASK) == RTLD_LAZY);
*_dl_global_scope_end = NULL;
}
if (l == new)
break;
l = l->l_prev;
}
new->l_global = (mode & RTLD_GLOBAL);
if (new->l_global)
{
/* The symbols of the new object and its dependencies are to be
introduced into the global scope that will be used to resolve
references from other dynamically-loaded objects. */
if (_dl_global_scope_alloc == 0)
{
/* This is the first dynamic object given global scope. */
_dl_global_scope_alloc = 8;
_dl_global_scope = malloc (8 * sizeof (struct link_map *));
if (! _dl_global_scope)
{
_dl_global_scope = _dl_default_scope;
nomem:
_dl_close (new);
_dl_signal_error (ENOMEM, file, "cannot extend global scope");
}
_dl_global_scope[2] = _dl_default_scope[2];
_dl_global_scope[3] = new;
_dl_global_scope[4] = NULL;
_dl_global_scope[5] = NULL;
}
else
{
if (_dl_global_scope_alloc <
(size_t) (_dl_global_scope_end - _dl_global_scope + 2))
{
/* Must extend the list. */
struct link_map **new = realloc (_dl_global_scope,
_dl_global_scope_alloc * 2);
if (! new)
goto nomem;
_dl_global_scope_end = new + (_dl_global_scope_end -
_dl_global_scope);
_dl_global_scope = new;
_dl_global_scope_alloc *= 2;
}
/* Append the new object and re-terminate the list. */
*_dl_global_scope_end++ = new;
/* We keep the list double-terminated so the last element
can be filled in for symbol lookups. */
_dl_global_scope_end[0] = NULL;
_dl_global_scope_end[1] = NULL;
}
}
/* Notify the debugger we have added some objects. We need to call
_dl_debug_initialize in a static program in case dynamic linking has
not been used before. */
r = _dl_debug_initialize (0);
r->r_state = RT_ADD;
_dl_debug_state ();
/* Run the initializer functions of new objects. */
while (init = _dl_init_next (new))
(*(void (*) (void)) init) ();
if (dl_start_ptr == NULL)
/* We must be the static _dl_open in libc.a because ld.so.1 is not
in scope. A static program that has loaded a dynamic object
now has competition. */
__libc_multiple_libcs = 1;
return new;
}
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