From 67e58f39412ecd4467034761f3f074283c90f3c8 Mon Sep 17 00:00:00 2001 From: Siddhesh Poyarekar Date: Sat, 31 Dec 2016 23:32:17 +0530 Subject: 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. --- csu/libc-start.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'csu/libc-start.c') diff --git a/csu/libc-start.c b/csu/libc-start.c index cc59073abe..15db9b4684 100644 --- a/csu/libc-start.c +++ b/csu/libc-start.c @@ -21,6 +21,9 @@ #include #include #include +#include + +#include extern void __libc_init_first (int argc, char **argv, char **envp); @@ -174,6 +177,11 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL), } } + /* Initialize very early so that tunables can use it. */ + __libc_init_secure (); + + __tunables_init (__environ); + /* Perform IREL{,A} relocations. */ apply_irel (); -- cgit v1.2.3