glibc/elf/dl-sym.c
Ulrich Drepper e4eb675d0c * elf/dl-close.c (free_mem): Free _dl_scope_free_list.
2007-06-13  Jakub Jelinek  <jakub@redhat.com>

	* include/link.h: Don't include rtld-lowlevel.h.
	(struct link_map): Remove l_scope_lock.
	* sysdeps/generic/ldsodefs.h: Don't include rtld-lowlevel.h.
	(_dl_scope_free_list): New field (variable) in _rtld_global.
	(DL_LOOKUP_SCOPE_LOCK): Remove.
	(_dl_scope_free): New prototype.
	* elf/dl-runtime.c (_dl_fixup): Don't use __rtld_mrlock_*lock.
	Don't pass DL_LOOKUP_SCOPE_LOCK to _dl_lookup_symbol_x.
	(_dl_profile_fixup): Likewise.
	* elf/dl-sym.c (do_sym): Likewise.  Use wrapped _dl_lookup_symbol_x
	whenever !RTLD_SINGLE_THREAD_P, use THREAD_GSCOPE_SET_FLAG and
	THREAD_GSCOPE_RESET_FLAG around it.
	* elf/dl-close.c (_dl_close_worker): Don't use
	__rtld_mrlock_{change,done}.  Call _dl_scope_free on the old
	scope.  Make sure THREAD_GSCOPE_WAIT () happens if any old
	scopes were queued or if l_scope_mem has been abandoned.
	* elf/dl-open.c (_dl_scope_free): New function.
	(dl_open_worker): Use it.  Don't use __rtld_mrlock_{change,done}.
	* elf/dl-support.c (_dl_scope_free_list): New variable.
	* elf/dl-lookup.c (add_dependency): Remove flags argument.
	Remove DL_LOOKUP_SCOPE_LOCK handling.
	(_dl_lookup_symbol_x): Adjust caller.  Remove DL_LOOKUP_SCOPE_LOCK
	handling.
	* elf/dl-object.c (_dl_new_object): Don't use
	__rtld_mrlock_initialize.

2007-06-19  Ulrich Drepper  <drepper@redhat.com>
2007-06-20 03:19:13 +00:00

274 lines
7.3 KiB
C

/* Look up a symbol in a shared object loaded by `dlopen'.
Copyright (C) 1999-2002,2004,2006,2007 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 <assert.h>
#include <stddef.h>
#include <setjmp.h>
#include <libintl.h>
#include <dlfcn.h>
#include <ldsodefs.h>
#include <dl-hash.h>
#include <sysdep-cancel.h>
#include <dl-tls.h>
#ifdef 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
struct call_dl_lookup_args
{
/* Arguments to do_dlsym. */
struct link_map *map;
const char *name;
struct r_found_version *vers;
int flags;
/* Return values of do_dlsym. */
lookup_t loadbase;
const ElfW(Sym) **refp;
};
static void
call_dl_lookup (void *ptr)
{
struct call_dl_lookup_args *args = (struct call_dl_lookup_args *) ptr;
args->map = GLRO(dl_lookup_symbol_x) (args->name, args->map, args->refp,
args->map->l_scope, args->vers, 0,
args->flags, NULL);
}
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
&& (l->l_contiguous || _dl_addr_inside_object (l, caller)))
{
match = l;
break;
}
if (handle == RTLD_DEFAULT)
{
/* Search the global scope. We have the simple case where
we look up in the scope of an object which was part of
the initial binary. And then the more complex part
where the object is dynamically loaded and the scope
array can change. */
if (RTLD_SINGLE_THREAD_P)
result = GLRO(dl_lookup_symbol_x) (name, match, &ref,
match->l_scope, vers, 0,
flags | DL_LOOKUP_ADD_DEPENDENCY,
NULL);
else
{
struct call_dl_lookup_args args;
args.name = name;
args.map = match;
args.vers = vers;
args.flags = flags | DL_LOOKUP_ADD_DEPENDENCY;
args.refp = &ref;
THREAD_GSCOPE_SET_FLAG ();
const char *objname;
const char *errstring = NULL;
bool malloced;
int err = GLRO(dl_catch_error) (&objname, &errstring, &malloced,
call_dl_lookup, &args);
THREAD_GSCOPE_RESET_FLAG ();
if (__builtin_expect (errstring != NULL, 0))
{
/* The lookup was unsuccessful. Rethrow the error. */
char *errstring_dup = strdupa (errstring);
char *objname_dup = strdupa (objname);
if (malloced)
free ((char *) errstring);
GLRO(dl_signal_error) (err, objname_dup, NULL, errstring_dup);
/* NOTREACHED */
}
result = args.map;
}
}
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;
#ifdef 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);
}