elf: Introduce to _dl_call_fini

This consolidates the destructor invocations from _dl_fini and
dlclose.  Remove the micro-optimization that avoids
calling _dl_call_fini if they are no destructors (as dlclose is quite
expensive anyway).  The debug log message is now printed
unconditionally.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Florian Weimer 2022-10-27 11:36:44 +02:00
parent a65ff76c9a
commit 6f360366f7
5 changed files with 61 additions and 78 deletions

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@ -53,6 +53,7 @@ routines = \
# profiled libraries.
dl-routines = \
dl-call-libc-early-init \
dl-call_fini \
dl-close \
dl-debug \
dl-debug-symbols \

50
elf/dl-call_fini.c Normal file
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@ -0,0 +1,50 @@
/* Invoke DT_FINI and DT_FINI_ARRAY callbacks.
Copyright (C) 1996-2022 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, see
<https://www.gnu.org/licenses/>. */
#include <ldsodefs.h>
#include <sysdep.h>
void
_dl_call_fini (void *closure_map)
{
struct link_map *map = closure_map;
/* When debugging print a message first. */
if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS))
_dl_debug_printf ("\ncalling fini: %s [%lu]\n\n", map->l_name, map->l_ns);
/* Make sure nothing happens if we are called twice. */
map->l_init_called = 0;
ElfW(Dyn) *fini_array = map->l_info[DT_FINI_ARRAY];
if (fini_array != NULL)
{
ElfW(Addr) *array = (ElfW(Addr) *) (map->l_addr
+ fini_array->d_un.d_ptr);
size_t sz = (map->l_info[DT_FINI_ARRAYSZ]->d_un.d_val
/ sizeof (ElfW(Addr)));
while (sz-- > 0)
((fini_t) array[sz]) ();
}
/* Next try the old-style destructor. */
ElfW(Dyn) *fini = map->l_info[DT_FINI];
if (fini != NULL)
DL_CALL_DT_FINI (map, ((void *) map->l_addr + fini->d_un.d_ptr));
}

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@ -36,11 +36,6 @@
#include <dl-unmap-segments.h>
/* Type of the constructor functions. */
typedef void (*fini_t) (void);
/* Special l_idx value used to indicate which objects remain loaded. */
#define IDX_STILL_USED -1
@ -110,31 +105,6 @@ remove_slotinfo (size_t idx, struct dtv_slotinfo_list *listp, size_t disp,
return false;
}
/* Invoke dstructors for CLOSURE (a struct link_map *). Called with
exception handling temporarily disabled, to make errors fatal. */
static void
call_destructors (void *closure)
{
struct link_map *map = closure;
if (map->l_info[DT_FINI_ARRAY] != NULL)
{
ElfW(Addr) *array =
(ElfW(Addr) *) (map->l_addr
+ map->l_info[DT_FINI_ARRAY]->d_un.d_ptr);
unsigned int sz = (map->l_info[DT_FINI_ARRAYSZ]->d_un.d_val
/ sizeof (ElfW(Addr)));
while (sz-- > 0)
((fini_t) array[sz]) ();
}
/* Next try the old-style destructor. */
if (map->l_info[DT_FINI] != NULL)
DL_CALL_DT_FINI (map, ((void *) map->l_addr
+ map->l_info[DT_FINI]->d_un.d_ptr));
}
void
_dl_close_worker (struct link_map *map, bool force)
{
@ -280,17 +250,7 @@ _dl_close_worker (struct link_map *map, bool force)
half-cooked objects. Temporarily disable exception
handling, so that errors are fatal. */
if (imap->l_init_called)
{
/* When debugging print a message first. */
if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS,
0))
_dl_debug_printf ("\ncalling fini: %s [%lu]\n\n",
imap->l_name, nsid);
if (imap->l_info[DT_FINI_ARRAY] != NULL
|| imap->l_info[DT_FINI] != NULL)
_dl_catch_exception (NULL, call_destructors, imap);
}
_dl_catch_exception (NULL, _dl_call_fini, imap);
#ifdef SHARED
/* Auditing checkpoint: we remove an object. */

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@ -21,11 +21,6 @@
#include <ldsodefs.h>
#include <elf-initfini.h>
/* Type of the constructor functions. */
typedef void (*fini_t) (void);
void
_dl_fini (void)
{
@ -116,38 +111,7 @@ _dl_fini (void)
if (l->l_init_called)
{
/* Make sure nothing happens if we are called twice. */
l->l_init_called = 0;
/* Is there a destructor function? */
if (l->l_info[DT_FINI_ARRAY] != NULL
|| (ELF_INITFINI && l->l_info[DT_FINI] != NULL))
{
/* When debugging print a message first. */
if (__builtin_expect (GLRO(dl_debug_mask)
& DL_DEBUG_IMPCALLS, 0))
_dl_debug_printf ("\ncalling fini: %s [%lu]\n\n",
DSO_FILENAME (l->l_name),
ns);
/* First see whether an array is given. */
if (l->l_info[DT_FINI_ARRAY] != NULL)
{
ElfW(Addr) *array =
(ElfW(Addr) *) (l->l_addr
+ l->l_info[DT_FINI_ARRAY]->d_un.d_ptr);
unsigned int i = (l->l_info[DT_FINI_ARRAYSZ]->d_un.d_val
/ sizeof (ElfW(Addr)));
while (i-- > 0)
((fini_t) array[i]) ();
}
/* Next try the old-style destructor. */
if (ELF_INITFINI && l->l_info[DT_FINI] != NULL)
DL_CALL_DT_FINI
(l, l->l_addr + l->l_info[DT_FINI]->d_un.d_ptr);
}
_dl_call_fini (l);
#ifdef SHARED
/* Auditing checkpoint: another object closed. */
_dl_audit_objclose (l);

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@ -105,6 +105,9 @@ typedef struct link_map *lookup_t;
DT_PREINIT_ARRAY. */
typedef void (*dl_init_t) (int, char **, char **);
/* Type of a constructor function, in DT_FINI, DT_FINI_ARRAY. */
typedef void (*fini_t) (void);
/* On some architectures a pointer to a function is not just a pointer
to the actual code of the function but rather an architecture
specific descriptor. */
@ -1048,6 +1051,11 @@ extern void _dl_init (struct link_map *main_map, int argc, char **argv,
initializer functions have completed. */
extern void _dl_fini (void) attribute_hidden;
/* Invoke the DT_FINI_ARRAY and DT_FINI destructors for MAP, which
must be a struct link_map *. Can be used as an argument to
_dl_catch_exception. */
void _dl_call_fini (void *map) attribute_hidden;
/* Sort array MAPS according to dependencies of the contained objects.
If FORCE_FIRST, MAPS[0] keeps its place even if the dependencies
say otherwise. */