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/* Load the dependencies of a mapped object.
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 <errno.h>
#include <dlfcn.h>
#include <stdlib.h>
void
_dl_map_object_deps (struct link_map *map,
struct link_map **preloads, unsigned int npreloads)
{
struct list
{
struct link_map *map;
struct list *next;
};
struct list head[1 + npreloads], *tailp, *scanp;
unsigned int nlist;
/* Start the search list with one element: MAP itself. */
head[0].map = map;
/* Add the preloaded items after MAP but before any of its dependencies. */
for (nlist = 0; nlist < npreloads; ++nlist)
{
head[nlist].next = &head[nlist + 1];
head[nlist + 1].map = preloads[nlist];
}
/* Terminate the list. */
head[nlist++].next = NULL;
/* We use `l_reserved' as a mark bit to detect objects we have already
put in the search list and avoid adding duplicate elements later in
the list. */
map->l_reserved = 1;
/* Process each element of the search list, loading each of its immediate
dependencies and appending them to the list as we step through it.
This produces a flat, ordered list that represents a breadth-first
search of the dependency tree. */
for (scanp = tailp = head; scanp; scanp = scanp->next)
{
struct link_map *l = scanp->map;
if (l->l_info[DT_NEEDED])
{
const char *strtab
= ((void *) l->l_addr + l->l_info[DT_STRTAB]->d_un.d_ptr);
const ElfW(Dyn) *d;
for (d = l->l_ld; d->d_tag != DT_NULL; ++d)
if (d->d_tag == DT_NEEDED)
{
/* Map in the needed object. */
struct link_map *dep
= _dl_map_object (l, strtab + d->d_un.d_val,
l->l_type == lt_executable ? lt_library :
l->l_type);
if (dep->l_reserved)
/* This object is already in the search list we are
building. Don't add a duplicate pointer. Release the
reference just added by _dl_map_object. */
--dep->l_opencount;
else
{
/* Append DEP to the search list. */
tailp->next = alloca (sizeof *tailp);
tailp = tailp->next;
tailp->map = dep;
tailp->next = NULL;
++nlist;
/* Set the mark bit that says it's already in the list. */
dep->l_reserved = 1;
}
}
}
}
/* Store the search list we built in the object. It will be used for
searches in the scope of this object. */
map->l_searchlist = malloc (nlist * sizeof (struct link_map *));
map->l_nsearchlist = nlist;
nlist = 0;
for (scanp = head; scanp; scanp = scanp->next)
{
map->l_searchlist[nlist++] = scanp->map;
/* Now clear all the mark bits we set in the objects on the search list
to avoid duplicates, so the next call starts fresh. */
scanp->map->l_reserved = 0;
}
}
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