* options.h (class General_options): Add -z relro.

	* layout.cc (Layout::Layout): Initialize relro_segment_.
	(Layout::add_output_section_data): Return the output section.
	(Layout::make_output_section): Rcognize relro sections and mark
	them appropriately.
	(Layout::attach_allocated_section_to_segment): Put relro sections
	in a PT_GNU_RELRO segment.
	(Layout::create_initial_dynamic_sections): Mark the .dynamic
	section as relro.
	(Layout::segment_precedes): Sort PT_GNU_RELRO segments after
	PT_TLS segments.
	(Layout::linkonce_mapping): Map d.rel.ro.local to
	.data.rel.ro.local.
	(Layout::output_section_name): Us .data.rel.ro.local for any
	section which begins with that.
	* layout.h (class Layout): Update add_output_section_data
	declaration.  Add relro_segment_ field.
	* output.cc (Output_section::Output_section): Initialize is_relro_
	and is_relro_local_ fields.
	(Output_segment::add_output_section): Group relro sections.
	(Output_segment::is_first_section_relro): New function.
	(Output_segment::maximum_alignment): If there is a relro section,
	align the segment to the common page size.
	(Output_segment::set_section_addresses): Track whether we are
	looking at relro sections.  If the last section is a relro
	section, align to the common page size.
	(Output_segment::set_section_list_addresses): Add in_relro
	parameter.  Change all callers.  Align to the page size when
	moving from relro to non-relro section.
	(Output_segment::set_offset): Align memsz of a PT_GNU_RELRO
	segment.
	* output.h (class Output_section): Add is_relro_ and
	is_relro_local_ fields.
	(Output_section::is_relro): New function.
	(Output_section::set_is_relro): New function.
	(Output_section::is_relro_local): New function.
	(Output_section::set_is_relro_local): New function.
	(class Output_segment): Update declarations.
	* i386.cc (Target_i386::got_section): Mark .got section as relro.
	* sparc.cc (Target_sparc::got_section): Likewise.
	* x86_64.cc (Target_x86_64::got_section): Likewise.
	* testsuite/relro_test_main.cc: New file.
	* testsuite/relro_test.cc: New file.
	* testsuite/Makefile.am (check_PROGRAMS): Add relro_test.
	(relro_test_SOURCES, relro_test_DEPENDENCIES): New variables.
	(relro_test_LDFLAGS, relro_test_LDADD): New variables.
	(relro_test.so, relro_test_pic.o): New targets.
	* testsuite/Makefile.in: Rebuild.

1 files changed, 114 insertions, 0 deletions

diff --git a/gold/testsuite/relro_test.cc b/gold/testsuite/relro_test.cc
new file mode 100644
index 0000000..d1bd9dd
--- /dev/null
+++ b/gold/testsuite/relro_test.cc
@@ -0,0 +1,114 @@
+// relro_test.cc -- test -z relro for gold
+
+// Copyright 2008 Free Software Foundation, Inc.
+// Written by Ian Lance Taylor <iant@google.com>.
+
+// This file is part of gold.
+
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+
+// This program 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 General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+// MA 02110-1301, USA.
+
+#include <cassert>
+#include <csignal>
+#include <stdint.h>
+#include <unistd.h>
+
+// This code is put into a shared library linked with -z relro.
+
+// i1 and i2 are not relro variables.
+int i1 = 1;
+static int i2 = 2;
+
+// P1 is a global relro variable.
+int* const p1 = &i1;
+
+// P2 is a local relro variable.
+int* const p2 = &i2;
+
+// Test symbol addresses.
+
+bool
+t1()
+{
+  void* i1addr = static_cast<void*>(&i1);
+  void* i2addr = static_cast<void*>(&i2);
+  const void* p1addr = static_cast<const void*>(&p1);
+  const void* p2addr = static_cast<const void*>(&p2);
+
+  // The relro variables should precede the non-relro variables in the
+  // memory image.
+  assert(i1addr > p1addr);
+  assert(i1addr > p2addr);
+  assert(i2addr > p1addr);
+  assert(i2addr > p2addr);
+
+  // The relro variables should not be on the same page as the
+  // non-relro variables.
+  const size_t page_size = getpagesize();
+  uintptr_t i1page = reinterpret_cast<uintptr_t>(i1addr) & ~ (page_size - 1);
+  uintptr_t i2page = reinterpret_cast<uintptr_t>(i2addr) & ~ (page_size - 1);
+  uintptr_t p1page = reinterpret_cast<uintptr_t>(p1addr) & ~ (page_size - 1);
+  uintptr_t p2page = reinterpret_cast<uintptr_t>(p2addr) & ~ (page_size - 1);
+  assert(i1page != p1page);
+  assert(i1page != p2page);
+  assert(i2page != p1page);
+  assert(i2page != p2page);
+
+  return true;
+}
+
+// A signal handler for SIGSEGV.
+
+extern "C"
+void
+sigsegv_handler(int)
+{
+  throw 0;
+}
+
+// Use a separate function to throw the exception, so that we don't
+// need to use -fnon-call-exceptions.
+
+void f2() __attribute__ ((noinline));
+void
+f2()
+{
+  int** pp1 = const_cast<int**>(&p1);
+  *pp1 = &i2;
+
+  // We shouldn't get here--the assignment to *pp1 should write to
+  // memory which the dynamic linker marked as read-only, giving us a
+  // SIGSEGV, causing sigsegv_handler to be invoked, to throw past us.
+  assert(0);
+}
+
+// Changing a relro variable should give us a SIGSEGV.
+
+bool
+t2()
+{
+  signal(SIGSEGV, sigsegv_handler);
+
+  try
+    {
+      f2();
+      return false;
+    }
+  catch (int i)
+    {
+      assert(i == 0);
+      return true;
+    }
+}