From: "Vivek Das Mohapatra" <vivek@collabora.com>
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 [thread overview]
Message-ID: <20210322154111.24798-5-vivek@collabora.com> (raw)
In-Reply-To: <20210322154111.24798-1-vivek@collabora.com>
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 +++
| 3 +++
htl/Makefile | 3 +++
iconvdata/Makefile | 3 +++
| 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 <link.h>
+
+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
--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))
--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
--
2.20.1
next prev parent reply other threads:[~2021-03-22 15:41 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 15:41 [RFC][PATCH v10 0/7] Implementation of RTLD_SHARED for dlmopen Vivek Das Mohapatra
2021-03-22 15:41 ` [RFC][PATCH v10 1/7] Define a new dynamic section tag - DT_GNU_FLAGS_1 (bug 22745) Vivek Das Mohapatra
2021-05-28 14:53 ` Adhemerval Zanella
2021-03-22 15:41 ` [RFC][PATCH v10 2/7] Abstract loaded-DSO search code into a helper function Vivek Das Mohapatra
2021-05-28 14:53 ` Adhemerval Zanella
2021-03-22 15:41 ` [RFC][PATCH v10 3/7] Use the new DSO finder " Vivek Das Mohapatra
2021-05-28 14:53 ` Adhemerval Zanella
2021-03-22 15:41 ` Vivek Das Mohapatra [this message]
2021-05-28 14:53 ` [RFC][PATCH v10 4/7] Add DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE to glibc DSOs (bug 22745) Adhemerval Zanella
2021-05-28 16:59 ` Adhemerval Zanella
2021-05-28 17:18 ` Andreas Schwab
2021-03-22 15:41 ` [RFC][PATCH v10 5/7] Implement dlmopen RTLD_SHARED flag " Vivek Das Mohapatra
2021-05-28 17:32 ` Adhemerval Zanella
2021-05-28 18:02 ` Adhemerval Zanella
2021-06-02 15:42 ` Vivek Das Mohapatra
2021-05-28 23:22 ` Vivek Das Mohapatra
2021-03-22 15:41 ` [RFC][PATCH v10 6/7] Add dlmopen / RTLD_SHARED tests Vivek Das Mohapatra
2021-03-22 15:41 ` [RFC][PATCH v10 7/7] Restore separate libc loading for the TLS/namespace storage test Vivek Das Mohapatra
2021-03-25 15:15 ` [RFC][PATCH v10 0/7] Implementation of RTLD_SHARED for dlmopen Vivek Das Mohapatra
2021-04-13 17:02 ` Vivek Das Mohapatra
2021-04-29 15:25 ` Vivek Das Mohapatra
2021-05-11 17:42 ` Vivek Das Mohapatra
2021-05-17 19:08 ` [PING][PATCH " Vivek Das Mohapatra
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