From patchwork Mon Mar 22 15:41:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vivek Dasmohapatra X-Patchwork-Id: 42738 X-Patchwork-Delegate: azanella@linux.vnet.ibm.com Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 25A413851C17; Mon, 22 Mar 2021 15:41:24 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 25A413851C17 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1616427684; bh=wKG1jf4/I3/UUllraLjEghlt6BuF64r6OidUL3pwHrA=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=ZomT/JyoXuF5Sv5nUJ4p7ym7IxoJfmE/TZ1SWNzODa7d9llWfzI3GIJHLgLJRLaB3 1Nxzg/9lf5BIWqUIfKuSAokCtsa81+9XeDfIImmC5DfJ0sHGYgSbnCsrniQpEK+clu 4sFm+ieB9WdHFf2wbwdvTjTGK46fi8fMUj4Q90RU= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by sourceware.org (Postfix) with ESMTPS id 6E6AC3854832 for ; Mon, 22 Mar 2021 15:41:19 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 6E6AC3854832 Received: from noise.cbg.collabora.co.uk (unknown [IPv6:2001:4d48:ad5c:ef00:8e70:5aff:fe59:c29c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: vivek) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id A56E91F44EA2 for ; Mon, 22 Mar 2021 15:41:18 +0000 (GMT) To: libc-alpha@sourceware.org Subject: [RFC][PATCH v10 4/7] Add DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE to glibc DSOs (bug 22745) Date: Mon, 22 Mar 2021 15:41:08 +0000 Message-Id: <20210322154111.24798-5-vivek@collabora.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210322154111.24798-1-vivek@collabora.com> References: <20210322154111.24798-1-vivek@collabora.com> MIME-Version: 1.0 X-Spam-Status: No, score=-12.4 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_PASS, SPF_PASS, TXREP, URIBL_BLACK autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: =?utf-8?q?Vivek_Das=C2=A0Mohapatra_via_Libc-alpha?= From: Vivek Dasmohapatra Reply-To: =?utf-8?q?Vivek_Das=C2=A0Mohapatra?= Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" libc.so, libpthread.so etc should have the new unique-dso-by-default flag set to allow dlmopen to work better (libc et al instance shared by default when DSOs dlmopened into a new namespace). --- Makeconfig | 3 +++ Makerules | 19 +++++++++++++- config.make.in | 1 + configure | 54 ++++++++++++++++++++++++++++++++++++--- configure.ac | 32 +++++++++++++++++++++-- dynamic-notes.c | 4 +++ elf/Makefile | 3 +++ extra-lib.mk | 3 +++ htl/Makefile | 3 +++ iconvdata/Makefile | 3 +++ iconvdata/extra-module.mk | 4 +++ nptl/Makefile | 3 +++ 12 files changed, 126 insertions(+), 6 deletions(-) create mode 100644 dynamic-notes.c diff --git a/Makeconfig b/Makeconfig index 01f8638c2e..7e1116163f 100644 --- a/Makeconfig +++ b/Makeconfig @@ -398,6 +398,9 @@ LDFLAGS-lib.so += -Wl,-z,now # Extra flags for dynamically linked non-test main programs. link-extra-flags += -Wl,-z,now endif +ifeq ($(ld-zunique),yes) +LDFLAGS-lib.so += -Wl,-z,unique +endif # Command to run after every final link (executable or shared object). # This is invoked with $(call after-link,...), so it should operate on diff --git a/Makerules b/Makerules index ca9885436e..d54767f3a6 100644 --- a/Makerules +++ b/Makerules @@ -581,7 +581,8 @@ $(common-objpfx)shlib.lds: $(common-objpfx)config.make $(..)Makerules PROVIDE(__start___libc_IO_vtables = .);\ __libc_IO_vtables : { *(__libc_IO_vtables) }\ PROVIDE(__stop___libc_IO_vtables = .);\ - /DISCARD/ : { *(.gnu.glibc-stub.*) }@' + /DISCARD/ : { *(.gnu.glibc-stub.*) }@' \ + -e 's/^.*\*(\.dynamic).*$$/ .dynamic : { *dynamic-notes.os(.dynamic) *(.dynamic) }/' test -s $@T mv -f $@T $@ common-generated += shlib.lds @@ -636,6 +637,17 @@ build-shlib-objlist = $(build-module-helper-objlist) \ # Also omits crti.o and crtn.o, which we do not want # since we define our own `.init' section specially. LDFLAGS-c.so = -nostdlib -nostartfiles + +# The stub dynamic-notes.os should not have weak/undefined symbol magic in it. +# It's not really part of the internals, rather it is a vector for linker magic +# which we need when the linker isn't new enough: +%/dynamic-notes.os: CPPFLAGS += -UMODULE_NAME +%/dynamic-notes.os: dynamic-notes.c + +ifeq ($(ld-zunique),yes) +LDFLAGS-c.so += -Wl,-z,unique +endif + # But we still want to link libc.so against $(libc.so-gnulib). LDLIBS-c.so += $(libc.so-gnulib) # Give libc.so an entry point and make it directly runnable itself. @@ -706,6 +718,11 @@ $(common-objpfx)linkobj/libc.so: $(common-objpfx)linkobj/libc_pic.a \ $(build-shlib) $(call after-link,$@) +ifneq ($(ld-zunique),yes) +$(common-objpfx)libc.so: $(common-objpfx)dynamic-notes.os +$(common-objpfx)linkobj/libc.so: $(common-objpfx)dynamic-notes.os +endif + ifeq ($(build-shared),yes) $(common-objpfx)libc.so: $(common-objpfx)libc.map endif diff --git a/config.make.in b/config.make.in index 7f47f0caa4..c2d818681b 100644 --- a/config.make.in +++ b/config.make.in @@ -72,6 +72,7 @@ have-cc-with-libunwind = @libc_cv_cc_with_libunwind@ fno-unit-at-a-time = @fno_unit_at_a_time@ bind-now = @bindnow@ have-hash-style = @libc_cv_hashstyle@ +ld-zunique = @ld_zunique@ use-default-link = @use_default_link@ have-cxx-thread_local = @libc_cv_cxx_thread_local@ have-loop-to-function = @libc_cv_cc_loop_to_function@ diff --git a/configure b/configure index 37cef37413..1040130d6c 100755 --- a/configure +++ b/configure @@ -685,6 +685,7 @@ hardcoded_path_in_tests enable_timezone_tools extra_nonshared_cflags use_default_link +ld_zunique sysheaders ac_ct_CXX CXXFLAGS @@ -731,6 +732,7 @@ infodir docdir oldincludedir includedir +runstatedir localstatedir sharedstatedir sysconfdir @@ -843,6 +845,7 @@ datadir='${datarootdir}' sysconfdir='${prefix}/etc' sharedstatedir='${prefix}/com' localstatedir='${prefix}/var' +runstatedir='${localstatedir}/run' includedir='${prefix}/include' oldincludedir='/usr/include' docdir='${datarootdir}/doc/${PACKAGE_TARNAME}' @@ -1095,6 +1098,15 @@ do | -silent | --silent | --silen | --sile | --sil) silent=yes ;; + -runstatedir | --runstatedir | --runstatedi | --runstated \ + | --runstate | --runstat | --runsta | --runst | --runs \ + | --run | --ru | --r) + ac_prev=runstatedir ;; + -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \ + | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \ + | --run=* | --ru=* | --r=*) + runstatedir=$ac_optarg ;; + -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb) ac_prev=sbindir ;; -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \ @@ -1232,7 +1244,7 @@ fi for ac_var in exec_prefix prefix bindir sbindir libexecdir datarootdir \ datadir sysconfdir sharedstatedir localstatedir includedir \ oldincludedir docdir infodir htmldir dvidir pdfdir psdir \ - libdir localedir mandir + libdir localedir mandir runstatedir do eval ac_val=\$$ac_var # Remove trailing slashes. @@ -1385,6 +1397,7 @@ Fine tuning of the installation directories: --sysconfdir=DIR read-only single-machine data [PREFIX/etc] --sharedstatedir=DIR modifiable architecture-independent data [PREFIX/com] --localstatedir=DIR modifiable single-machine data [PREFIX/var] + --runstatedir=DIR modifiable per-process data [LOCALSTATEDIR/run] --libdir=DIR object code libraries [EPREFIX/lib] --includedir=DIR C header files [PREFIX/include] --oldincludedir=DIR C header files for non-gcc [/usr/include] @@ -3331,6 +3344,7 @@ fi + # Check whether --with-default-link was given. if test "${with_default_link+set}" = set; then : withval=$with_default_link; use_default_link=$withval @@ -5976,6 +5990,34 @@ fi $as_echo "$libc_cv_hashstyle" >&6; } +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for linker DT_GNU_FLAGS_1/ DF_GNU_1_UNIQUE support" >&5 +$as_echo_n "checking for linker DT_GNU_FLAGS_1/ DF_GNU_1_UNIQUE support... " >&6; } +if ${libc_cv_ld_zunique+:} false; then : + $as_echo_n "(cached) " >&6 +else + cat > conftest.ld.c <<\EOF +int x (void) { return 0; } +EOF +libc_cv_ld_zunique=no; +if { ac_try='${CC-cc} -Wl,--fatal-warnings -Wl,-z,unique -shared -o conftest.ld.so conftest.ld.c' + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5 + (eval $ac_try) 2>&5 + ac_status=$? + $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5 + test $ac_status = 0; }; } +then + libc_cv_ld_zunique=yes +else + echo >&5 "\ +${CC-cc} does not support -Wl,-z,unique from: +$ac_try" +fi; +ld_zunique=$libc_cv_ld_zunique +rm -f conftest* +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_ld_zunique" >&5 +$as_echo "$libc_cv_ld_zunique" >&6; } + # The linker's default -shared behavior is good enough if it # does these things that our custom linker scripts ensure that # all allocated NOTE sections come first. @@ -6021,10 +6063,16 @@ EOF esac shift 2 done - case "$libc_seen_a$libc_seen_b" in - yesyes) + case "$libc_seen_a$libc_seen_b$libc_cv_ld_zunique" in + yesyesyes) libc_cv_use_default_link=yes ;; + yesyesno) + echo >&5 "\ +shared layout from: +$ac_try +is OK but -Wl,-z,unique is unsupported anyway" + ;; *) echo >&5 "\ $libc_seen_a$libc_seen_b from: diff --git a/configure.ac b/configure.ac index 16b15b6f90..178874aa12 100644 --- a/configure.ac +++ b/configure.ac @@ -148,6 +148,7 @@ AC_ARG_WITH([headers], [sysheaders='']) AC_SUBST(sysheaders) +AC_SUBST(ld_zunique) AC_SUBST(use_default_link) AC_ARG_WITH([default-link], AS_HELP_STRING([--with-default-link], @@ -1352,6 +1353,27 @@ fi rm -f conftest*]) AC_SUBST(libc_cv_hashstyle) +AC_CACHE_CHECK([for linker DT_GNU_FLAGS_1/ DF_GNU_1_UNIQUE support], + libc_cv_ld_zunique, [dnl +cat > conftest.ld.c <<\EOF +int x (void) { return 0; } +EOF +libc_cv_ld_zunique=no; +dnl FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME +dnl THIS IS DELIBERATELY WRONG SO WE CAN TEST BUILDING WITH A TOO-OLD LINKER +dnl FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME +if AC_TRY_COMMAND([dnl +${CC-cc} -Wl,--fatal-warnings -Wl,-z,unique -shared -o conftest.ld.so conftest.ld.c]) +then + libc_cv_ld_zunique=yes +else + echo >&AS_MESSAGE_LOG_FD "\ +${CC-cc} does not support -Wl,-z,unique from: +$ac_try" +fi; +ld_zunique=$libc_cv_ld_zunique +rm -f conftest*]) + # The linker's default -shared behavior is good enough if it # does these things that our custom linker scripts ensure that # all allocated NOTE sections come first. @@ -1390,10 +1412,16 @@ EOF esac shift 2 done - case "$libc_seen_a$libc_seen_b" in - yesyes) + case "$libc_seen_a$libc_seen_b$libc_cv_ld_zunique" in + yesyesyes) libc_cv_use_default_link=yes ;; + yesyesno) + echo >&AS_MESSAGE_LOG_FD "\ +shared layout from: +$ac_try +is OK but -Wl,-z,unique is unsupported anyway" + ;; *) echo >&AS_MESSAGE_LOG_FD "\ $libc_seen_a$libc_seen_b from: diff --git a/dynamic-notes.c b/dynamic-notes.c new file mode 100644 index 0000000000..d0b487e970 --- /dev/null +++ b/dynamic-notes.c @@ -0,0 +1,4 @@ +#include + +const ElfW(Dyn) __dynamic_note __attribute__ ((section (".dynamic"))) = + { .d_tag = DT_GNU_FLAGS_1, .d_un.d_val = DF_GNU_1_UNIQUE }; diff --git a/elf/Makefile b/elf/Makefile index 3b8e13e066..22f2a87fcb 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -102,6 +102,9 @@ endif ifeq (yes,$(build-shared)) extra-objs = $(all-rtld-routines:%=%.os) sofini.os interp.os +ifneq (yes,$(ld-zunique)) +extra-objs += ../dynamic-notes.os +endif generated += librtld.os dl-allobjs.os ld.so ldd install-others = $(inst_rtlddir)/$(rtld-installed-name) install-bin-script = ldd diff --git a/extra-lib.mk b/extra-lib.mk index 72f8d2e1df..4e4a447d5e 100644 --- a/extra-lib.mk +++ b/extra-lib.mk @@ -101,6 +101,9 @@ $(objpfx)$(lib).so: $(firstword $($(lib)-map) \ $(addprefix $(common-objpfx), \ $(filter $(lib).map, \ $(version-maps)))) +ifneq ($(ld-zunique),yes) +$(objpfx)$(lib).so: $(common-objpfx)dynamic-notes.os +endif endif endif diff --git a/htl/Makefile b/htl/Makefile index 895a6f777c..65ddd202a1 100644 --- a/htl/Makefile +++ b/htl/Makefile @@ -205,6 +205,9 @@ libc-link.so = $(common-objpfx)libc.so extra-B-pthread.so = -B$(common-objpfx)htl/ LDFLAGS-pthread.so = -Wl,--enable-new-dtags,-z,nodelete,-z,initfirst +ifeq ($(ld-zunique),yes) +LDFLAGS-pthread.so += -Wl,-z,unique +endif include ../Rules diff --git a/iconvdata/Makefile b/iconvdata/Makefile index 55c527a5f7..2fe2404ade 100644 --- a/iconvdata/Makefile +++ b/iconvdata/Makefile @@ -67,6 +67,9 @@ modules := ISO8859-1 ISO8859-2 ISO8859-3 ISO8859-4 ISO8859-5 \ ifeq ($(bind-now),yes) LDFLAGS.so += -Wl,-z,now endif +ifeq ($(ld-zunique),yes) +LDFLAGS.so += -Wl,-z,unique +endif modules.so := $(addsuffix .so, $(modules)) diff --git a/iconvdata/extra-module.mk b/iconvdata/extra-module.mk index ecaf507624..4d81358f19 100644 --- a/iconvdata/extra-module.mk +++ b/iconvdata/extra-module.mk @@ -7,6 +7,10 @@ $(objpfx)$(mod).so: $(addprefix $(objpfx),$(addsuffix .os,$($(mod)-routines)))\ $(shlib-lds) $(link-libc-deps) $(build-module-asneeded) +ifneq ($(ld-zunique),yes) +$(objpfx)$(mod).so: $(common-objpfx)dynamic-notes.os +endif + ifneq (,$(extra-modules-left)) include extra-module.mk endif diff --git a/nptl/Makefile b/nptl/Makefile index b1948cc47a..dedfe389c0 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -396,6 +396,9 @@ tests-printers-libs := $(static-thread-library) endif LDFLAGS-pthread.so = -Wl,--enable-new-dtags,-z,nodelete,-z,initfirst +ifeq ($(ld-zunique),yes) +LDFLAGS-pthread.so += -Wl,-z,unique +endif tests += tst-cancelx7 tst-cancelx17 tst-cleanupx4