elf: Restore ldconfig libc6 implicit soname logic [BZ #30125]

While cleaning up old libc version support, the deprecated libc4 code was
accidentally kept in `implicit_soname`, instead of the libc6 code.

This causes additional symlinks to be created by `ldconfig` for libraries
without a soname, e.g. a library `libsomething.123.456.789` without a soname
will create a `libsomething.123` -> `libsomething.123.456.789` symlink.

As the libc6 version of the `implicit_soname` code is a trivial `xstrdup`,
just inline it and remove `implicit_soname` altogether.

Some further simplification looks possible (e.g. the call to `create_links`
looks like a no-op if `soname == NULL`, other than the verbose printfs), but
logic is kept as-is for now.

Fixes: BZ #30125
Fixes: 8ee878592c4a ("Assume only FLAG_ELF_LIBC6 suport")
Signed-off-by: Joan Bruguera <joanbrugueram@gmail.com>

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/elf/tst-ldconfig-soname.sh b/elf/tst-ldconfig-soname.sh
new file mode 100644
index 0000000000..406f526dbf
--- /dev/null
+++ b/elf/tst-ldconfig-soname.sh
@@ -0,0 +1,49 @@
+#!/bin/sh
+# Test that ldconfig creates symlinks according to the library's soname
+# (and in particular, does not create symlinks for libraries without a soname)
+# Copyright (C) 2000-2023 Free Software Foundation, Inc.
+# Copyright The GNU Toolchain Authors.
+# This file is part of the GNU C Library.
+
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <https://www.gnu.org/licenses/>.
+
+set -ex
+
+common_objpfx=$1
+test_wrapper_env=$2
+run_program_env=$3
+
+testroot="${common_objpfx}elf/bug30125-test-directory"
+cleanup () {
+    rm -rf "$testroot"
+}
+trap cleanup 0
+
+rm -rf "$testroot"
+mkdir -p $testroot/lib
+cp "${common_objpfx}elf/tst-ldconfig-soname-lib-with-soname.so" \
+    $testroot/lib/libtst-ldconfig-soname-lib-with-soname.so.1.2.3
+cp "${common_objpfx}elf/tst-ldconfig-soname-lib-without-soname.so" \
+    $testroot/lib/libtst-ldconfig-soname-lib-without-soname.so.1.2.3
+
+${test_wrapper_env} \
+${run_program_env} \
+${common_objpfx}elf/ldconfig -vn $testroot/lib
+
+LINKS=$(cd $testroot/lib && find . -type l)
+if [ "$LINKS" != "./libtst-ldconfig-soname-lib-with-soname.so.1" ]; then
+    echo "error: $0 - extra symlinks found"
+    exit 1
+fi