Add a test for --clear-symbol-version

This test removes the __libc_start_main@GLIBC_2.34 symbol, which should
be the only GLIBC_2.34 symbol in 'main' when built with recent (i.e., >
2.34) glibc. Because it is the only symbol, the entry in .gnu.version_r
should also be removed.

Because this is a symbol version test, it's unlikely to work on musl or
anything else which doesn't use glibc symbol versions. In these cases
(or in the case that __libc_start_main is now at a different version),
the test should print a warning, but exit with "0" to report a pass.

Author: sulix

tests/Makefile.am

@@ -41,7 +41,8 @@ src_TESTS = \
   phdr-corruption.sh \
   replace-needed.sh \
   replace-add-needed.sh \
-  add-debug-tag.sh
+  add-debug-tag.sh \
+  clear-symver.sh
 
 build_TESTS = \
   $(no_rpath_arch_TESTS)

tests/clear-symver.sh

@@ -0,0 +1,33 @@
+#! /bin/sh -e
+SCRATCH=scratch/$(basename $0 .sh)
+
+rm -rf ${SCRATCH}
+mkdir -p ${SCRATCH}
+
+cp main ${SCRATCH}/
+
+SYMBOL_TO_REMOVE=__libc_start_main
+VERSION_TO_REMOVE=GLIBC_2.34a
+
+readelfData=$(readelf -V ${SCRATCH}/main 2>&1)
+
+if [ $(echo "$readelfData" | grep --count "$VERSION_TO_REMOVE") -lt 2 ]; then
+    # We expect this to appear at least twice: once for the symbol entry,
+    # and once for verneed entry.
+    echo "Warning: Couldn't find expected versioned symbol."
+    echo "This is probably because you're either not using glibc, or"
+    echo "${SYMBOL_TO_REMOVE} is no longer at version ${VERSION_TO_REMOVE}"
+    echo "Reporting a pass anyway, as the test result is invalid."
+    exit 0
+fi
+
+../src/patchelf --clear-symbol-version ${SYMBOL_TO_REMOVE} ${SCRATCH}/main
+
+readelfData=$(readelf -V ${SCRATCH}/main 2>&1)
+
+if [ $(echo "$readelfData" | grep --count "$VERSION_TO_REMOVE") -ne 0 ]; then
+    # We expect this to appear at least twice: once for the symbol entry,
+    # and once for verneed entry.
+    echo "The symbol version ${SYMBOL_TO_REMOVE} remained behind!"
+    exit 1
+fi