Move libc_freeres_ptrs and libc_subfreeres to hidden/weak functions

They are both used by __libc_freeres to free all library malloc
allocated resources to help tooling like mtrace or valgrind with
memory leak tracking.

The current scheme uses assembly markers and linker script entries
to consolidate the free routine function pointers in the RELRO segment
and to be freed buffers in BSS.

This patch changes it to use specific free functions for
libc_freeres_ptrs buffers and call the function pointer array directly
with call_function_static_weak.

It allows the removal of both the internal macros and the linker
script sections.

Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>

6 files changed, 31 insertions, 7 deletions

diff --git a/sysdeps/unix/sysv/linux/check_pf.c b/sysdeps/unix/sysv/linux/check_pf.c
index de20712..b157c51 100644
--- a/sysdeps/unix/sysv/linux/check_pf.c
+++ b/sysdeps/unix/sysv/linux/check_pf.c
@@ -362,7 +362,8 @@ __check_pf (bool *seen_ipv4, bool *seen_ipv6,
 }
 
 /* Free the cache if it has been allocated.  */
-libc_freeres_fn (freecache)
+void
+__check_pf_freemem (void)
 {
   if (cache)
     __free_in6ai (cache->in6ai);
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/getutent.c b/sysdeps/unix/sysv/linux/s390/s390-32/getutent.c
index d8188f8..562495b 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/getutent.c
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/getutent.c
@@ -25,6 +25,7 @@
 # define weak_alias(n,a)
 #endif
 #include "login/getutent.c"
+_weak_alias (buffer, __libc_getutent_freemem_ptr)
 
 #if defined SHARED
 default_symbol_version (__getutent, getutent, UTMP_COMPAT_BASE);
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/getutid.c b/sysdeps/unix/sysv/linux/s390/s390-32/getutid.c
index cd981c7..ccdc25b 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/getutid.c
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/getutid.c
@@ -25,6 +25,7 @@
 # define weak_alias(n,a)
 #endif
 #include "login/getutid.c"
+_weak_alias (buffer, __libc_getutid_freemem_ptr)
 
 #if defined SHARED
 default_symbol_version (__getutid, getutid, UTMP_COMPAT_BASE);
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/getutline.c b/sysdeps/unix/sysv/linux/s390/s390-32/getutline.c
index 0b61161..16e8f17 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/getutline.c
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/getutline.c
@@ -25,6 +25,7 @@
 # define weak_alias(n,a)
 #endif
 #include "login/getutline.c"
+_weak_alias (buffer, __libc_getutline_freemem_ptr)
 
 #if defined SHARED
 default_symbol_version (__getutline, getutline, UTMP_COMPAT_BASE);
diff --git a/sysdeps/unix/sysv/linux/set-freeres-os.h b/sysdeps/unix/sysv/linux/set-freeres-os.h
new file mode 100644
index 0000000..964c9a4
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/set-freeres-os.h
@@ -0,0 +1,24 @@
+/* System specific resource deallocation.  Linux version.
+   Copyright (C) 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/>.  */
+
+extern void __check_pf_freemem (void) attribute_hidden;
+extern char * __ttyname_freemem_ptr attribute_hidden;
+
+#define call_freeres_os_funcs			  \
+  call_function_static_weak (__check_pf_freemem); \
+  call_free_static_weak (__ttyname_freemem_ptr)
diff --git a/sysdeps/unix/sysv/linux/ttyname.c b/sysdeps/unix/sysv/linux/ttyname.c
index f3870f8..406fbb3 100644
--- a/sysdeps/unix/sysv/linux/ttyname.c
+++ b/sysdeps/unix/sysv/linux/ttyname.c
@@ -19,15 +19,11 @@
 #include <limits.h>
 #include <termios.h>
 #include <stdlib.h>
-
+#include <set-freeres.h>
 #include "ttyname.h"
 
 static char *ttyname_buf = NULL;
-
-libc_freeres_fn (free_mem)
-{
-  free (ttyname_buf);
-}
+weak_alias (ttyname_buf, __ttyname_freemem_ptr)
 
 /* Return the pathname of the terminal FD is open on, or NULL on errors.
    The returned storage is good only until the next call to this function.  */