From patchwork Thu Jul 8 16:32:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vivek Dasmohapatra X-Patchwork-Id: 44257 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 2EEF23938C27 for ; Thu, 8 Jul 2021 16:36:27 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 2EEF23938C27 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1625762187; bh=vW00ktRM1QfwCelPGqGfGHrSFMBHOk8m2alVZ3RZzLE=; 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=TaemIFBMIJnBS5VPCyW9HgD2S1e8nceoiXRRx7UrVHAg0ScruYnsixlyg+i3XLTl7 B9pDAaIkspsg6By89OopsAz9YrVKJyArKaj43ubdV9TaACjwd/uyfUHfltPJjEr3nb 6fzGSqnA1FnGhIYNXc8//1vxKr0abl6H4K/p+imI= 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 F08AF393A43E for ; Thu, 8 Jul 2021 16:33:04 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org F08AF393A43E 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 4F0611F43F5B for ; Thu, 8 Jul 2021 17:33:03 +0100 (BST) To: libc-alpha@sourceware.org Subject: [RFC][PATCH v12 4/8] Add DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE to glibc DSOs (bug 22745) Date: Thu, 8 Jul 2021 17:32:51 +0100 Message-Id: <20210708163255.812-5-vivek@collabora.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210708163255.812-1-vivek@collabora.com> References: <20210708163255.812-1-vivek@collabora.com> MIME-Version: 1.0 X-Spam-Status: No, score=-12.1 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=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) 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+patchwork=sourceware.org@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). Reviewed-by: Adhemerval Zanella --- Makeconfig | 3 +++ Makerules | 18 ++++++++++++++++- config.make.in | 1 + configure | 42 ++++++++++++++++++++++++++++++++++++--- configure.ac | 31 ++++++++++++++++++++++++++--- elf/Makefile | 3 +++ elf/dynamic-notes.c | 4 ++++ extra-lib.mk | 3 +++ htl/Makefile | 3 +++ iconvdata/Makefile | 3 +++ iconvdata/extra-module.mk | 4 ++++ nptl/Makefile | 7 ++++++- 12 files changed, 114 insertions(+), 8 deletions(-) create mode 100644 elf/dynamic-notes.c diff --git a/Makeconfig b/Makeconfig index efc7351d71..baa893840e 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 596fa68376..66c1251754 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 +637,16 @@ build-shlib-objlist = $(build-module-helper-objlist) \ # Also omits crti.o and crtn.o, which we do not want # since we define our own `.init' section specially. LDFLAGS-c.so = -nostdlib -nostartfiles + +# The stub dynamic-notes.os should not have weak/undefined symbol magic in it. +# It's not really part of the internals, rather it is a vector for linker magic +# which we need when the linker isn't new enough: +%/dynamic-notes.os: CPPFLAGS += -UMODULE_NAME + +ifeq ($(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 +717,11 @@ $(common-objpfx)linkobj/libc.so: $(common-objpfx)linkobj/libc_pic.a \ $(build-shlib) $(call after-link,$@) +ifneq ($(ld-zunique),yes) +$(common-objpfx)libc.so: $(common-objpfx)elf/dynamic-notes.os +$(common-objpfx)linkobj/libc.so: $(common-objpfx)elf/dynamic-notes.os +endif + ifeq ($(build-shared),yes) $(common-objpfx)libc.so: $(common-objpfx)libc.map endif diff --git a/config.make.in b/config.make.in index cbf59114b0..8755490c13 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 9619c10991..a53243a178 100755 --- a/configure +++ b/configure @@ -625,6 +625,7 @@ libc_cv_cc_nofma libc_cv_mtls_dialect_gnu2 fno_unit_at_a_time libc_cv_has_glob_dat +ld_zunique libc_cv_hashstyle libc_cv_fpie libc_cv_z_execstack @@ -6074,9 +6075,38 @@ 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 $ac_status = 0; }; } +then + libc_cv_ld_zunique=yes +fi; +ld_zunique=$libc_cv_ld_zunique +rm -f conftest* +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_ld_zunique" >&5 +$as_echo "$libc_cv_ld_zunique" >&6; } + + # The linker's default -shared behavior is good enough if it # does these things that our custom linker scripts ensure that -# all allocated NOTE sections come first. +# all allocated NOTE sections come first AND it understands +# -z unique should result in DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE +# sections in its output. if test "$use_default_link" = default; then { $as_echo "$as_me:${as_lineno-$LINENO}: checking for sufficient default -shared layout" >&5 $as_echo_n "checking for sufficient default -shared layout... " >&6; } @@ -6119,10 +6149,16 @@ EOF esac shift 2 done - case "$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 so linker scripts are required" + ;; *) echo >&5 "\ $libc_seen_a$libc_seen_b from: diff --git a/configure.ac b/configure.ac index 34ecbba540..9369bcbebe 100644 --- a/configure.ac +++ b/configure.ac @@ -1372,9 +1372,28 @@ 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; + +if AC_TRY_COMMAND([dnl +${CC-cc} -Wl,--fatal-warnings -Wl,-z,unique -shared -o conftest.ld.so conftest.ld.c]) +then + libc_cv_ld_zunique=yes +fi; +ld_zunique=$libc_cv_ld_zunique +rm -f conftest*]) +AC_SUBST(ld_zunique) + # 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. +# all allocated NOTE sections come first AND it understands +# -z unique should result in DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE +# sections in its output. if test "$use_default_link" = default; then AC_CACHE_CHECK([for sufficient default -shared layout], libc_cv_use_default_link, [dnl @@ -1410,10 +1429,16 @@ EOF esac shift 2 done - case "$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 so linker scripts are required" + ;; *) echo >&AS_MESSAGE_LOG_FD "\ $libc_seen_a$libc_seen_b from: diff --git a/elf/Makefile b/elf/Makefile index 698a6ab985..9734030c23 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -103,6 +103,9 @@ 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/elf/dynamic-notes.c b/elf/dynamic-notes.c new file mode 100644 index 0000000000..d0b487e970 --- /dev/null +++ b/elf/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/extra-lib.mk b/extra-lib.mk index 72f8d2e1df..9051958ec0 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)/elf/dynamic-notes.os +endif endif endif diff --git a/htl/Makefile b/htl/Makefile index cf9d12fc12..c2a25dcd79 100644 --- a/htl/Makefile +++ b/htl/Makefile @@ -203,6 +203,9 @@ 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 ($(ld-zunique),yes) +LDFLAGS-pthread.so += -Wl,-z,unique +endif include ../Rules diff --git a/iconvdata/Makefile b/iconvdata/Makefile index bb3f621b49..4170005322 100644 --- a/iconvdata/Makefile +++ b/iconvdata/Makefile @@ -67,6 +67,9 @@ modules := ISO8859-1 ISO8859-2 ISO8859-3 ISO8859-4 ISO8859-5 \ ifeq ($(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..92c3ab4d7b 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: $(common-objpfx)/elf/dynamic-notes.os +endif + ifneq (,$(extra-modules-left)) include extra-module.mk endif diff --git a/nptl/Makefile b/nptl/Makefile index 9b94bfcd31..81353b9455 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -375,7 +375,12 @@ CPPFLAGS-tst-pthread-gdb-attach-static.c := \ # were launched with an explicit ld.so invocation. tst-pthread-gdb-attach-no-pie = yes -tests += tst-cancelx7 tst-cancelx17 +LDFLAGS-pthread.so = -Wl,--enable-new-dtags,-z,nodelete,-z,initfirst +ifeq ($(ld-zunique),yes) +LDFLAGS-pthread.so += -Wl,-z,unique +endif + +tests += tst-cancelx7 tst-cancelx17 tst-cleanupx4 ifeq ($(build-shared),yes) tests += tst-compat-forwarder tst-audit-threads