sys-libs/db: use --version-script instead of --default-symver for ld.{gold,lld}

[telans]

ld.{gold,lld} do not supprt --default-symver. Using the --version-script script provided fixes configure and outputs symbol names matching --default-symver.

ld.bfd (default-symver)	ld.{gold,lld} (version-script)
T __txn_stat_print_pp@@libdb-6.0.so@@libdb-6.0.so T __txn_updateckp@@libdb-6.0.so@@libdb-6.0.so D __txn_xa_regop_42_desc@@libdb-6.0.so@@libdb-6.0.so T __txn_xa_regop_42_verify@@libdb-6.0.so@@libdb-6.0.so T __ua_memcpy@@libdb-6.0.so@@libdb-6.0.so	T __txn_stat_print_pp@@libdb-6.0.so@@libdb-6.0.so T __txn_updateckp@@libdb-6.0.so@@libdb-6.0.so D __txn_xa_regop_42_desc@@libdb-6.0.so@@libdb-6.0.so T __txn_xa_regop_42_verify@@libdb-6.0.so@@libdb-6.0.so T __ua_memcpy@@libdb-6.0.so@@libdb-6.0.so

Closes: https://bugs.gentoo.org/729510
Closes: https://bugs.gentoo.org/595108
Package-Manager: Portage-3.0.13, Repoman-3.0.2
Signed-off-by: Theo Anderson telans@posteo.de

[gentoo-bot]

Pull Request assignment

Submitter: @telans
Areas affected: ebuilds
Packages affected: sys-libs/db

sys-libs/db: @gentoo/base-system

Linked bugs

Bugs linked: 595108, 729510

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[gentoo-repo-qa-bot]

Pull request CI report

Report generated at: 2021-01-18 05:30 UTC
Newest commit scanned: 55db4fe
Status: ✅ good

There are existing issues already. Please look into the report to make sure none of them affect the packages in question:
https://qa-reports.gentoo.org/output/gentoo-ci/80e82439f6/output.html

[Arfrever]

Not having versions of symbols (which is currently done by -Wl,--default-symver) will degrade ABI and allow run-time collisions of symbols in programs, which through their dependencies pull multiple versions of sys-libs/db.

See versions of symbols:

$ (for lib in /usr/lib64/libdb-*.so; do echo "==================== ${lib##*/} ===================="; nm -CD --with-symbol-versions "${lib}" | grep @@libdb; done)

[telans]

Would you mind taking a gander at this?

diff --git a/sys-libs/db/db-6.0.35-r3.ebuild b/sys-libs/db/db-6.0.35-r3.ebuild
index f1c5a7c3c5d..ac543a7e914 100644
--- a/sys-libs/db/db-6.0.35-r3.ebuild
+++ b/sys-libs/db/db-6.0.35-r3.ebuild
@@ -116,6 +116,11 @@ src_prepare() {
 	sed \
 		-e '/db_repsite/s,Skipping:,Skipping,g' \
 		-i "${S_BASE}"/test/tcl/reputils.tcl || die
+
+	# Version script for ld.{gold,lld} which do not supprt --default-symver
+	cat > "${S}"/db-version-script.ver <<-EOF
+	libdb-${SLOT}.so {*;};
+	EOF
 }
 
 multilib_src_configure() {
@@ -147,7 +152,12 @@ multilib_src_configure() {
 	# Add linker versions to the symbols. Easier to do, and safer than header file
 	# mumbo jumbo.
 	if use userland_GNU ; then
-		append-ldflags -Wl,--default-symver
+		# ld.{gold,lld} do not supprt --default-symver
+		if tc-ld-is-gold || tc-ld-is-lld; then
+			append-ldflags -Wl,--version-script="${S}"/db-version-script.ver
+		else
+			append-ldflags -Wl,--default-symver
+		fi
 	fi
 
 	# use `set` here since the java opts will contain whitespace

Using that --version-script results in symbol names which mimick --default-symver:

I'll push this change as it seems acceptable to me.

[gentoo-repo-qa-bot]

Pull request CI report

Report generated at: 2021-01-18 22:50 UTC
Newest commit scanned: b5f83f2
Status: ✅ good

There are existing issues already. Please look into the report to make sure none of them affect the packages in question:
https://qa-reports.gentoo.org/output/gentoo-ci/abde752cd4/output.html

[Arfrever]

Besides libdb-${SLOT}.so, there are few other libraries.
E.g. USE="cxx" enables libdb_cxx-${SLOT}.so and libdb_stl-${SLOT}.so.

Currently defined symbols in libdb_cxx-${SLOT}.so have version libdb_cxx-${SLOT}.so, and defined symbols in libdb_stl-${SLOT}.so have version libdb_stl-${SLOT}.so.

Using your version script (with libdb-${SLOT}.so {*;};) for all libraries would result in using the same version libdb-${SLOT}.so for all libraries.
This could still be problem, because there are symbols differing only in their versions.
Example:

$ nm -CD --with-symbol-versions /usr/lib64/libdb-5.3.so | grep db_create@@libdb
000000000003e980 T __bam_db_create@@libdb-5.3.so
0000000000062ea0 T __ham_db_create@@libdb-5.3.so
000000000007bde0 T __heap_db_create@@libdb-5.3.so
0000000000085e10 T __qam_db_create@@libdb-5.3.so
00000000001134a0 T db_create@@libdb-5.3.so
$ nm -CD --with-symbol-versions /usr/lib64/libdb_cxx-5.3.so | grep db_create@@libdb
0000000000062c50 T __bam_db_create@@libdb_cxx-5.3.so
0000000000087170 T __ham_db_create@@libdb_cxx-5.3.so
00000000000a0090 T __heap_db_create@@libdb_cxx-5.3.so
00000000000aa0c0 T __qam_db_create@@libdb_cxx-5.3.so
0000000000137730 T db_create@@libdb_cxx-5.3.so
$ nm -CD --with-symbol-versions /usr/lib64/libdb_stl-5.3.so | grep db_create@@libdb
0000000000073540 T __bam_db_create@@libdb_stl-5.3.so
0000000000097a60 T __ham_db_create@@libdb_stl-5.3.so
00000000000b0980 T __heap_db_create@@libdb_stl-5.3.so
00000000000ba9b0 T __qam_db_create@@libdb_stl-5.3.so
0000000000148020 T db_create@@libdb_stl-5.3.so

So you would need to create separate and slightly different version scripts for each library.

[telans]

Thanks for the tips, this definitely requires more work.

[telans]

Closing in favour of #19116 which matches tc-ld-diable-gold within these ebuilds.