[patch] Fix for BZ 16381 -- explicit loader invocation "ld.so ./a.out" on a PIE binary calls global ctors twice

[Paul Pluzhnikov]

Greetings,

This patch fixes BZ 16381 -- explicit loader invocation "ld.so ./a.out" 
on a PIE binary calls global ctors twice.

Thanks,

2014-01-11  Paul Pluzhnikov  <ppluzhnikov@google.com>

	* elf/Makefile: Add tst-pie2
	* elf/tst-pie2.c: New file.
	* elf/rtld.c (dl_main): Mark main executable as such.

-------------- next part --------------
diff --git a/elf/Makefile b/elf/Makefile
index 4c58fc9..055ea38 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -214,8 +214,8 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
 		tst-array5dep tst-null-argv-lib
 ifeq (yesyes,$(have-fpie)$(build-shared))
 modules-names += tst-piemod1
-tests += tst-pie1
-tests-pie += tst-pie1
+tests += tst-pie1 tst-pie2
+tests-pie += tst-pie1 tst-pie2
 endif
 modules-execstack-yes = tst-execstack-mod
 extra-test-objs += $(addsuffix .os,$(strip $(modules-names)))
@@ -882,6 +882,7 @@ $(objpfx)tst-array5-static.out: tst-array5-static.exp \
 	cmp $@ tst-array5-static.exp > /dev/null
 
 CFLAGS-tst-pie1.c += $(pie-ccflag)
+CFLAGS-tst-pie2.c += $(pie-ccflag)
 
 $(objpfx)tst-pie1: $(objpfx)tst-piemod1.so
 
diff --git a/elf/rtld.c b/elf/rtld.c
index 6dcbabc..3e0bae4 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -1101,6 +1101,9 @@ of this helper program; chances are you did not intend to run this program.\n\
 	 implementations which has no real free() function it does not
 	 makes sense to free the old string first.  */
       main_map->l_name = (char *) "";
+      /* l_type is already lt_executable for ET_EXEC, but not for a PIE
+         binary, which is ET_DYN.  */
+      main_map->l_type = lt_executable;
       *user_entry = main_map->l_entry;
 
 #ifdef HAVE_AUX_VECTOR
diff --git a/elf/tst-pie2.c b/elf/tst-pie2.c
new file mode 100644
index 0000000..14cbf93
--- /dev/null
+++ b/elf/tst-pie2.c
@@ -0,0 +1,37 @@
+/* Copyright (C) 2014 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
+   <http://www.gnu.org/licenses/>.  */
+
+/* Test case for BZ 16381  */
+
+#include <assert.h>
+
+static int g;
+
+void init_g (void) __attribute__((constructor));
+
+void
+init_g (void)
+{
+  assert (g == 0);
+  g += 1;
+}
+
+int
+main (int argc, char *argv[])
+{
+  return 0;
+}