[PATCH 1/1] elf: Limit tst-prelink-cmp target archs

[Matheus Castanho]

Follow up from [0].

[0] https://sourceware.org/pipermail/libc-alpha/2020-November/119970.html

---8<---

elf/tst-prelink-cmp was initially added for x86 (commit fe534fe898) to validate
the fix for Bug 19178, and later applied to all architectures that use GLOB_DAT
relocations (commit 89569c8bb6).  However, that bug only affected targets that
handle GLOB_DAT relocations as ELF_TYPE_CLASS_EXTERN_PROTECTED_DATA, so the test
should only apply to targets defining DL_EXTERN_PROTECTED_DATA, which gates the
usage of the elf type class above.  For all other targets not meeting that
criteria, the test now returns with UNSUPPORTED status.

---
 elf/Makefile          |  9 ++------
 elf/tst-prelink-cmp.c | 48 +++++++++++++++++++++++++++++++++++++++++++
 elf/tst-prelink.exp   |  1 -
 3 files changed, 50 insertions(+), 8 deletions(-)
 create mode 100644 elf/tst-prelink-cmp.c
 delete mode 100644 elf/tst-prelink.exp

diff --git a/elf/Makefile b/elf/Makefile
index 0b4d78c874..9d171416ad 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -453,12 +453,10 @@ update-all-abi: update-all-abi-ld

 ifeq ($(have-glob-dat-reloc),yes)
 tests += tst-prelink
+tests-internal += tst-prelink-cmp
 # Don't compile tst-prelink.c with PIE for GLOB_DAT relocation.
 CFLAGS-tst-prelink.c += -fno-pie
 tst-prelink-no-pie = yes
-ifeq ($(run-built-tests),yes)
-tests-special += $(objpfx)tst-prelink-cmp.out
-endif
 endif

 # The test requires shared _and_ PIE because the executable
@@ -1599,10 +1597,7 @@ tst-prelink-ENV = LD_TRACE_PRELINKING=1
 $(objpfx)tst-prelink-conflict.out: $(objpfx)tst-prelink.out
 	grep stdout $< | grep conflict | $(AWK) '{ print $$10, $$11 }' > $@

-$(objpfx)tst-prelink-cmp.out: tst-prelink.exp \
-			      $(objpfx)tst-prelink-conflict.out
-	cmp $^ > $@; \
-	$(evaluate-test)
+$(objpfx)tst-prelink-cmp.out: $(objpfx)tst-prelink-conflict.out

 $(objpfx)tst-ldconfig-X.out : tst-ldconfig-X.sh $(objpfx)ldconfig
 	$(SHELL) $< '$(common-objpfx)' '$(test-wrapper-env)' \
diff --git a/elf/tst-prelink-cmp.c b/elf/tst-prelink-cmp.c
new file mode 100644
index 0000000000..5d21f1ddfd
--- /dev/null
+++ b/elf/tst-prelink-cmp.c
@@ -0,0 +1,48 @@
+/* Test the output from the environment variable, LD_TRACE_PRELINKING,
+   for prelink.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   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/>.  */
+
+#include <ldsodefs.h>
+#include <support/check.h>
+#include <support/xstdio.h>
+#include <support/support.h>
+#include <support/test-driver.h>
+
+static int
+do_test (void)
+{
+#ifndef DL_EXTERN_PROTECTED_DATA
+  return EXIT_UNSUPPORTED;
+#else
+  char *src = xasprintf ("%s/elf/tst-prelink-conflict.out", support_objdir_root);
+  FILE *f = xfopen (src,"r");
+  size_t buffer_length = 0;
+  char *buffer = NULL;
+
+  const char *expected = "/0 stdout\n";
+
+  xgetline (&buffer, &buffer_length, f);
+  TEST_COMPARE_STRING (expected, buffer);
+
+  free (buffer);
+  xfclose (f);
+  return 0;
+#endif
+}
+
+#include <support/test-driver.c>
diff --git a/elf/tst-prelink.exp b/elf/tst-prelink.exp
deleted file mode 100644
index b35b4c9705..0000000000
--- a/elf/tst-prelink.exp
+++ /dev/null
@@ -1 +0,0 @@
-/0 stdout
--
2.26.2