[glibc] elf: Introduce to _dl_call_fini

[glibc] elf: Introduce to _dl_call_fini

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=6f360366f7f76b158a0f4bf20d42f2854ad56264

commit 6f360366f7f76b158a0f4bf20d42f2854ad56264
Author: Florian Weimer <fweimer@redhat.com>
Date:   Thu Oct 27 11:36:44 2022 +0200

    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>

Diff:
---
 elf/Makefile               |  1 +
 elf/dl-call_fini.c         | 50 ++++++++++++++++++++++++++++++++++++++++++++++
 elf/dl-close.c             | 42 +-------------------------------------
 elf/dl-fini.c              | 38 +----------------------------------
 sysdeps/generic/ldsodefs.h |  8 ++++++++
 5 files changed, 61 insertions(+), 78 deletions(-)

diff --git a/elf/Makefile b/elf/Makefile
index 7b50ccc07a..86c960cf8a 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -53,6 +53,7 @@ routines = \
 # profiled libraries.
 dl-routines = \
   dl-call-libc-early-init \
+  dl-call_fini \
   dl-close \
   dl-debug \
   dl-debug-symbols \
diff --git a/elf/dl-call_fini.c b/elf/dl-call_fini.c
new file mode 100644
index 0000000000..9e7ba10fa2
--- /dev/null
+++ b/elf/dl-call_fini.c
@@ -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));
+}
diff --git a/elf/dl-close.c b/elf/dl-close.c
index bcd6e206e9..14deca2e2b 100644
--- a/elf/dl-close.c
+++ b/elf/dl-close.c
@@ -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.  */
diff --git a/elf/dl-fini.c b/elf/dl-fini.c
index 030b1fcbcd..50ff94db16 100644
--- a/elf/dl-fini.c
+++ b/elf/dl-fini.c
@@ -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);
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 0223aa9f12..2747f88d0e 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -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.  */