Add framework for tunables

The tunables framework allows us to uniformly manage and expose global
variables inside glibc as switches to users.  tunables/README has
instructions for glibc developers to add new tunables.

Tunables support can be enabled by passing the --enable-tunables
configure flag to the configure script.  This patch only adds a
framework and does not pose any limitations on how tunable values are
read from the user.  It also adds environment variables used in malloc
behaviour tweaking to the tunables framework as a PoC of the
compatibility interface.

	* manual/install.texi: Add --enable-tunables option.
	* INSTALL: Regenerate.
	* README.tunables: New file.
	* Makeconfig (CPPFLAGS): Define TOP_NAMESPACE.
	(before-compile): Generate dl-tunable-list.h early.
	* config.h.in: Add HAVE_TUNABLES.
	* config.make.in: Add have-tunables.
	* configure.ac: Add --enable-tunables option.
	* configure: Regenerate.
	* csu/init-first.c (__libc_init_first): Move
	__libc_init_secure earlier...
	* csu/init-first.c (LIBC_START_MAIN):... to here.
	Include dl-tunables.h, libc-internal.h.
	(LIBC_START_MAIN) [!SHARED]: Initialize tunables for static
	binaries.
	* elf/Makefile (dl-routines): Add dl-tunables.
	* elf/Versions (ld): Add __tunable_set_val to GLIBC_PRIVATE
	namespace.
	* elf/dl-support (_dl_nondynamic_init): Unset MALLOC_CHECK_
	only when !HAVE_TUNABLES.
	* elf/rtld.c (process_envvars): Likewise.
	* elf/dl-sysdep.c [HAVE_TUNABLES]: Include dl-tunables.h
	(_dl_sysdep_start): Call __tunables_init.
	* elf/dl-tunable-types.h: New file.
	* elf/dl-tunables.c: New file.
	* elf/dl-tunables.h: New file.
	* elf/dl-tunables.list: New file.
	* malloc/tst-malloc-usable-static.c: New test case.
	* malloc/Makefile (tests-static): Add it.
	* malloc/arena.c [HAVE_TUNABLES]: Include dl-tunables.h.
	Define TUNABLE_NAMESPACE.
	(DL_TUNABLE_CALLBACK (set_mallopt_check)): New function.
	(DL_TUNABLE_CALLBACK_FNDECL): New macro.  Use it to define
	callback functions.
	(ptmalloc_init): Set tunable values.
	* scripts/gen-tunables.awk: New file.
	* sysdeps/mach/hurd/dl-sysdep.c: Include dl-tunables.h.
	(_dl_sysdep_start): Call __tunables_init.

1 files changed, 41 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index d219e5432b..85a4ac30df 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,44 @@
+2016-12-31  Siddhesh Poyarekar  <siddhesh@sourceware.org>
+
+	* manual/install.texi: Add --enable-tunables option.
+	* INSTALL: Regenerate.
+	* README.tunables: New file.
+	* Makeconfig (CPPFLAGS): Define TOP_NAMESPACE.
+	(before-compile): Generate dl-tunable-list.h early.
+	* config.h.in: Add HAVE_TUNABLES.
+	* config.make.in: Add have-tunables.
+	* configure.ac: Add --enable-tunables option.
+	* configure: Regenerate.
+	* csu/init-first.c (__libc_init_first): Move
+	__libc_init_secure earlier...
+	* csu/init-first.c (LIBC_START_MAIN):... to here.
+	Include dl-tunables.h, libc-internal.h.
+	(LIBC_START_MAIN) [!SHARED]: Initialize tunables for static
+	binaries.
+	* elf/Makefile (dl-routines): Add dl-tunables.
+	* elf/Versions (ld): Add __tunable_set_val to GLIBC_PRIVATE
+	namespace.
+	* elf/dl-support (_dl_nondynamic_init): Unset MALLOC_CHECK_
+	only when !HAVE_TUNABLES.
+	* elf/rtld.c (process_envvars): Likewise.
+	* elf/dl-sysdep.c [HAVE_TUNABLES]: Include dl-tunables.h
+	(_dl_sysdep_start): Call __tunables_init.
+	* elf/dl-tunable-types.h: New file.
+	* elf/dl-tunables.c: New file.
+	* elf/dl-tunables.h: New file.
+	* elf/dl-tunables.list: New file.
+	* malloc/tst-malloc-usable-static.c: New test case.
+	* malloc/Makefile (tests-static): Add it.
+	* malloc/arena.c [HAVE_TUNABLES]: Include dl-tunables.h.
+	Define TUNABLE_NAMESPACE.
+	(DL_TUNABLE_CALLBACK (set_mallopt_check)): New function.
+	(DL_TUNABLE_CALLBACK_FNDECL): New macro.  Use it to define
+	callback functions.
+	(ptmalloc_init): Set tunable values.
+	* scripts/gen-tunables.awk: New file.
+	* sysdeps/mach/hurd/dl-sysdep.c: Include dl-tunables.h.
+	(_dl_sysdep_start): Call __tunables_init.
+
 2016-12-31  Florian Weimer  <fweimer@redhat.com>
 
 	* resolv/resolv.h (RES_BLAST): Deprecate.