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/* Look up a symbol in a shared object loaded by `dlopen'.
Copyright (C) 1999,2000,2001,2002,2004,2006 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 Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <stddef.h>
#include <setjmp.h>
#include <libintl.h>
#include <dlfcn.h>
#include <ldsodefs.h>
#include <dl-hash.h>
#ifdef USE_TLS
# include <dl-tls.h>
#endif
#if defined USE_TLS && defined SHARED
/* Systems which do not have tls_index also probably have to define
DONT_USE_TLS_INDEX. */
# ifndef __TLS_GET_ADDR
# define __TLS_GET_ADDR __tls_get_addr
# endif
/* Return the symbol address given the map of the module it is in and
the symbol record. This is used in dl-sym.c. */
static void *
internal_function
_dl_tls_symaddr (struct link_map *map, const ElfW(Sym) *ref)
{
# ifndef DONT_USE_TLS_INDEX
tls_index tmp =
{
.ti_module = map->l_tls_modid,
.ti_offset = ref->st_value
};
return __TLS_GET_ADDR (&tmp);
# else
return __TLS_GET_ADDR (map->l_tls_modid, ref->st_value);
# endif
}
#endif
static void *
internal_function
do_sym (void *handle, const char *name, void *who,
struct r_found_version *vers, int flags)
{
const ElfW(Sym) *ref = NULL;
lookup_t result;
ElfW(Addr) caller = (ElfW(Addr)) who;
/* If the address is not recognized the call comes from the main
program (we hope). */
struct link_map *match = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
/* Find the highest-addressed object that CALLER is not below. */
for (Lmid_t ns = 0; ns < DL_NNS; ++ns)
for (struct link_map *l = GL(dl_ns)[ns]._ns_loaded; l != NULL;
l = l->l_next)
if (caller >= l->l_map_start && caller < l->l_map_end)
{
/* There must be exactly one DSO for the range of the virtual
memory. Otherwise something is really broken. */
match = l;
break;
}
if (handle == RTLD_DEFAULT)
/* Search the global scope. */
result = GLRO(dl_lookup_symbol_x) (name, match, &ref, match->l_scope,
vers, 0, flags|DL_LOOKUP_ADD_DEPENDENCY,
NULL);
else if (handle == RTLD_NEXT)
{
if (__builtin_expect (match == GL(dl_ns)[LM_ID_BASE]._ns_loaded, 0))
{
if (match == NULL
|| caller < match->l_map_start
|| caller >= match->l_map_end)
GLRO(dl_signal_error) (0, NULL, NULL, N_("\
RTLD_NEXT used in code not dynamically loaded"));
}
struct link_map *l = match;
while (l->l_loader != NULL)
l = l->l_loader;
result = GLRO(dl_lookup_symbol_x) (name, match, &ref, l->l_local_scope,
vers, 0, 0, match);
}
else
{
/* Search the scope of the given object. */
struct link_map *map = handle;
result = GLRO(dl_lookup_symbol_x) (name, map, &ref, map->l_local_scope,
vers, 0, flags, NULL);
}
if (ref != NULL)
{
void *value;
#if defined USE_TLS && defined SHARED
if (ELFW(ST_TYPE) (ref->st_info) == STT_TLS)
/* The found symbol is a thread-local storage variable.
Return the address for to the current thread. */
value = _dl_tls_symaddr (result, ref);
else
#endif
value = DL_SYMBOL_ADDRESS (result, ref);
#ifdef SHARED
/* Auditing checkpoint: we have a new binding. Provide the
auditing libraries the possibility to change the value and
tell us whether further auditing is wanted. */
if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
{
const char *strtab = (const char *) D_PTR (result,
l_info[DT_STRTAB]);
/* Compute index of the symbol entry in the symbol table of
the DSO with the definition. */
unsigned int ndx = (ref - (ElfW(Sym) *) D_PTR (result,
l_info[DT_SYMTAB]));
if ((match->l_audit_any_plt | result->l_audit_any_plt) != 0)
{
unsigned int altvalue = 0;
struct audit_ifaces *afct = GLRO(dl_audit);
/* Synthesize a symbol record where the st_value field is
the result. */
ElfW(Sym) sym = *ref;
sym.st_value = (ElfW(Addr)) value;
for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
{
if (afct->symbind != NULL
&& ((match->l_audit[cnt].bindflags & LA_FLG_BINDFROM)
!= 0
|| ((result->l_audit[cnt].bindflags & LA_FLG_BINDTO)
!= 0)))
{
unsigned int flags = altvalue | LA_SYMB_DLSYM;
uintptr_t new_value
= afct->symbind (&sym, ndx,
&match->l_audit[cnt].cookie,
&result->l_audit[cnt].cookie,
&flags, strtab + ref->st_name);
if (new_value != (uintptr_t) sym.st_value)
{
altvalue = LA_SYMB_ALTVALUE;
sym.st_value = new_value;
}
}
afct = afct->next;
}
value = (void *) sym.st_value;
}
}
#endif
return value;
}
return NULL;
}
void *
internal_function
_dl_vsym (void *handle, const char *name, const char *version, void *who)
{
struct r_found_version vers;
/* Compute hash value to the version string. */
vers.name = version;
vers.hidden = 1;
vers.hash = _dl_elf_hash (version);
/* We don't have a specific file where the symbol can be found. */
vers.filename = NULL;
return do_sym (handle, name, who, &vers, 0);
}
void *
internal_function
_dl_sym (void *handle, const char *name, void *who)
{
return do_sym (handle, name, who, NULL, DL_LOOKUP_RETURN_NEWEST);
}
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