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>

2 files changed, 142 insertions, 73 deletions

diff --git a/include/libc-symbols.h b/include/libc-symbols.h
index 404169ce78..155781d448 100644
--- a/include/libc-symbols.h
+++ b/include/libc-symbols.h
@@ -237,79 +237,6 @@ requires at runtime the shared libraries from the glibc version used \
 for linking")
 #endif
 
-/* Resource Freeing Hooks:
-
-   Normally a process exits and the OS cleans up any allocated
-   memory.  However, when tooling like mtrace or valgrind is monitoring
-   the process we need to free all resources that are part of the
-   process in order to provide the consistency required to track
-   memory leaks.
-
-   A single public API exists and is __libc_freeres(), and this is used
-   by applications like valgrind to freee resouces.
-
-   There are 3 cases:
-
-   (a) __libc_freeres
-
-	In this case all you need to do is define the freeing routine:
-
-	foo.c:
-	libfoo_freeres_fn (foo_freeres)
-	{
-	  complex_free (mem);
-	}
-
-	This ensures the function is called at the right point to free
-	resources.
-
-   (b) __libc_freeres_ptr
-
-	The framework for (a) iterates over the list of pointers-to-free
-	in (b) and frees them.
-
-	foo.c:
-	libc_freeres_ptr (static char *foo_buffer);
-
-	Freeing these resources alaways happens last and is equivalent
-	to registering a function that does 'free (foo_buffer)'.
-
-   (c) Explicit lists of free routines to call or objects to free.
-
-	It is the intended goal to remove (a) and (b) which have some
-	non-determinism based on link order, and instead use explicit
-	lists of functions and frees to resolve cleanup ordering issues
-	and make it easy to debug and maintain.
-
-	As of today the following subsystems use (c):
-
-	Per-thread cleanup:
-	* malloc/thread-freeres.c
-
-	libdl cleanup:
-	* dlfcn/dlfreeres.c
-
-	libpthread cleanup:
-	* nptl/nptlfreeres.c
-
-	So if you need any shutdown routines to run you should add them
-	directly to the appropriate subsystem's shutdown list.  */
-
-/* Resource pointers to free in libc.so.  */
-#define libc_freeres_ptr(decl) \
-  __make_section_unallocated ("__libc_freeres_ptrs, \"aw\", %nobits") \
-  decl __attribute__ ((section ("__libc_freeres_ptrs" __sec_comment)))
-
-/* Resource freeing functions from libc.so go in this section.  */
-#define __libc_freeres_fn_section \
-  __attribute__ ((__used__, section ("__libc_freeres_fn")))
-
-/* Resource freeing functions for libc.so.  */
-#define libc_freeres_fn(name) \
-  static void name (void) __attribute_used__ __libc_freeres_fn_section;	\
-  text_set_element (__libc_subfreeres, name);				\
-  static void name (void)
-
 /* Declare SYMBOL to be TYPE (`function' or `object') of SIZE bytes
    alias to ORIGINAL, when the assembler supports such declarations
    (such as in ELF).
diff --git a/include/set-freeres.h b/include/set-freeres.h
new file mode 100644
index 0000000000..b7f66519a3
--- /dev/null
+++ b/include/set-freeres.h
@@ -0,0 +1,142 @@
+/* Macros for internal resource Freeing Hooks.
+   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/>.  */
+
+#ifndef _SET_FREERES_H
+#define _SET_FREERES_H 1
+
+#include <shlib-compat.h>
+#include <printf.h>
+#include <time.h>
+#include <resolv/resolv-internal.h>
+
+/* Resource Freeing Hooks:
+
+   Normally a process exits and the OS cleans up any allocated
+   memory.  However, when tooling like mtrace or valgrind is monitoring
+   the process we need to free all resources that are part of the
+   process in order to provide the consistency required to track
+   memory leaks.
+
+   A single public API exists and is __libc_freeres, and this is used
+   by applications like valgrind to freee resouces.
+
+   Each free routines must be explicit listed below.  */
+
+/* From libc.so.  */
+extern void __dl_libc_freemem (void) attribute_hidden;
+extern void __hdestroy (void) attribute_hidden;
+extern void __gconv_cache_freemem (void) attribute_hidden;
+extern void __gconv_conf_freemem (void) attribute_hidden;
+extern void __gconv_db_freemem (void) attribute_hidden;
+extern void __gconv_dl_freemem (void) attribute_hidden;
+extern void __intl_freemem (void) attribute_hidden;
+extern void __libio_freemem (void) attribute_hidden;
+extern void __libc_fstab_freemem (void) attribute_hidden;
+extern void __nscd_gr_map_freemem (void) attribute_hidden;
+extern void __nscd_hst_map_freemem (void) attribute_hidden;
+extern void __nscd_pw_map_freemem (void) attribute_hidden;
+extern void __nscd_serv_map_freemem (void) attribute_hidden;
+extern void __nscd_group_map_freemem (void) attribute_hidden;
+extern void __libc_regcomp_freemem (void) attribute_hidden;
+extern void __libc_atfork_freemem (void) attribute_hidden;
+extern void __libc_resolv_conf_freemem (void) attribute_hidden;
+extern void __res_thread_freeres (void) attribute_hidden;
+extern void __libc_printf_freemem (void) attribute_hidden;
+extern void __libc_fmtmsg_freemem (void) attribute_hidden;
+extern void __libc_setenv_freemem (void) attribute_hidden;
+#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_31)
+extern void __rpc_freemem (void) attribute_hidden;
+extern void __rpc_thread_destroy (void) attribute_hidden;
+#endif
+extern void __libc_getaddrinfo_freemem (void) attribute_hidden;
+extern void __libc_tzset_freemem (void) attribute_hidden;
+extern void __libc_localealias_freemem (void) attribute_hidden;
+extern void __libc_getutent_freemem (void) attribute_hidden;
+extern void __libc_getutline_freemem (void) attribute_hidden;
+/* From nss/nss_module.c */
+extern void __nss_module_freeres (void) attribute_hidden;
+/* From nss/nss_action.c */
+extern void __nss_action_freeres (void) attribute_hidden;
+/* From nss/nss_database.c */
+extern void __nss_database_freeres (void) attribute_hidden;
+/* From libio/genops.c */
+extern int _IO_cleanup (void) attribute_hidden;;
+/* From dlfcn/dlerror.c */
+extern void __libc_dlerror_result_free (void) attribute_hidden;
+
+/* From either libc.so or libpthread.so  */
+extern void __libpthread_freeres (void) attribute_hidden;
+/* From either libc.so or libanl.so  */
+#if PTHREAD_IN_LIBC
+extern void __gai_freemem (void) attribute_hidden;
+/* From either libc.so or librt.so  */
+extern void __aio_freemem (void) attribute_hidden;
+#endif
+
+/* From libc.so  */
+extern char * __libc_fgetgrent_freemem_ptr attribute_hidden;
+extern char * __libc_fgetsgent_freeres_ptr attribute_hidden;
+extern char * __libc_getnetgrent_freemem_ptr attribute_hidden;
+extern char * __libc_rcmd_freemem_ptr attribute_hidden;
+extern char * __libc_rexec_freemem_ptr attribute_hidden;
+extern void * __libc_mntent_freemem_ptr attribute_hidden;
+extern char * __libc_fgetpwent_freemem_ptr attribute_hidden;
+extern struct netaddr * __libc_resolv_res_hconf_freemem_ptr attribute_hidden;
+extern char * __libc_fgetspent_freemem_ptr attribute_hidden;
+extern __time64_t * __libc_tzfile_freemem_ptr attribute_hidden;
+extern char * __libc_getnameinfo_freemem_ptr attribute_hidden;
+extern struct utmp * __libc_getutent_freemem_ptr attribute_hidden;
+extern struct utmp * __libc_getutid_freemem_ptr attribute_hidden;
+extern struct utmp * __libc_getutline_freemem_ptr attribute_hidden;
+extern printf_arginfo_size_function ** __libc_reg_printf_freemem_ptr
+    attribute_hidden;
+extern printf_va_arg_function ** __libc_reg_type_freemem_ptr
+    attribute_hidden;
+/* From nss/getXXbyYY.c  */
+extern char * __libc_getgrgid_freemem_ptr attribute_hidden;
+extern char * __libc_getgrnam_freemem_ptr attribute_hidden;
+extern char * __libc_getpwnam_freemem_ptr attribute_hidden;
+extern char * __libc_getpwuid_freemem_ptr attribute_hidden;
+extern char * __libc_getspnam_freemem_ptr attribute_hidden;
+extern char * __libc_getaliasbyname_freemem_ptr attribute_hidden;
+extern char * __libc_gethostbyaddr_freemem_ptr attribute_hidden;
+extern char * __libc_gethostbyname_freemem_ptr attribute_hidden;
+extern char * __libc_gethostbyname2_freemem_ptr attribute_hidden;
+extern char * __libc_getnetbyaddr_freemem_ptr attribute_hidden;
+extern char * __libc_getnetbyname_freemem_ptr attribute_hidden;
+extern char * __libc_getprotobynumber_freemem_ptr attribute_hidden;
+extern char * __libc_getprotobyname_freemem_ptr attribute_hidden;
+extern char * __libc_getrpcbyname_freemem_ptr attribute_hidden;
+extern char * __libc_getrpcbynumber_freemem_ptr attribute_hidden;
+extern char * __libc_getservbyname_freemem_ptr attribute_hidden;
+extern char * __libc_getservbyport_freemem_ptr attribute_hidden;
+/* From nss/getXXent.c */
+extern char * __libc_getgrent_freemem_ptr attribute_hidden;
+extern char * __libc_getpwent_freemem_ptr attribute_hidden;
+extern char * __libc_getspent_freemem_ptr attribute_hidden;
+extern char * __libc_getaliasent_freemem_ptr attribute_hidden;
+extern char * __libc_gethostent_freemem_ptr attribute_hidden;
+extern char * __libc_getnetent_freemem_ptr attribute_hidden;
+extern char * __libc_getprotoent_freemem_ptr attribute_hidden;
+extern char * __libc_getrpcent_freemem_ptr attribute_hidden;
+extern char * __libc_getservent_freemem_ptr attribute_hidden;
+/* From misc/efgcvt-template.c  */
+extern char * __libc_efgcvt_freemem_ptr attribute_hidden;
+extern char * __libc_qefgcvt_freemem_ptr attribute_hidden;
+
+#endif