[PATCH] Set NODELETE flag when opening already open objects with RTLD_NODELETE

["Siddhesh Poyarekar" <siddhesh at redhat dot com>]

The DF_1_NODELETE flag is set too late when opening a DSO, due to
which, if a DSO is already open, subsequently opening it with
RTLD_NODELETE fails to set the DF_1_NODELETE flag.  This patch fixes
this by setting the flag immediately after bumping the opencount.

Verified on x86_64.

Siddhesh

	[BZ #18676]
	* elf/tst-nodelete-opened.c: New test case.
	* elf/tst-nodelete-opened-lib.c: New test case module.
	* elf/Makefile (tests, modules-names): Use them.
	* elf/dl-open.c (dl_open_worker): Set DF_1_NODELETE flag
	early.
---
 elf/Makefile                  |  6 +++--
 elf/dl-open.c                 | 11 ++++----
 elf/tst-nodelete-opened-lib.c | 19 ++++++++++++++
 elf/tst-nodelete-opened.c     | 58 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 87 insertions(+), 7 deletions(-)
 create mode 100644 elf/tst-nodelete-opened-lib.c
 create mode 100644 elf/tst-nodelete-opened.c

diff --git a/elf/Makefile b/elf/Makefile
index 90d5058..4ceeaf8 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -148,7 +148,7 @@ tests += loadtest restest1 preloadtest loadfail multiload origtest resolvfail \
 	 tst-unique1 tst-unique2 $(if $(CXX),tst-unique3 tst-unique4 \
 	 tst-nodelete) \
 	 tst-initorder tst-initorder2 tst-relsort1 tst-null-argv \
-	 tst-ptrguard1 tst-tlsalign tst-tlsalign-extern
+	 tst-ptrguard1 tst-tlsalign tst-tlsalign-extern tst-nodelete-opened
 #	 reldep9
 ifeq ($(build-hardcoded-path-in-tests),yes)
 tests += tst-dlopen-aout
@@ -218,7 +218,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
 		tst-initorder2d \
 		tst-relsort1mod1 tst-relsort1mod2 tst-array2dep \
 		tst-array5dep tst-null-argv-lib \
-		tst-tlsalign-lib
+		tst-tlsalign-lib tst-nodelete-opened-lib
 ifeq (yes,$(have-protected-data))
 modules-names += tst-protected1moda tst-protected1modb
 tests += tst-protected1a tst-protected1b
@@ -525,6 +525,8 @@ $(objpfx)tst-initordera4.so: $(objpfx)tst-initordera3.so
 $(objpfx)tst-initorder: $(objpfx)tst-initordera4.so $(objpfx)tst-initordera1.so $(objpfx)tst-initorderb2.so
 $(objpfx)tst-null-argv: $(objpfx)tst-null-argv-lib.so
 $(objpfx)tst-tlsalign: $(objpfx)tst-tlsalign-lib.so
+$(objpfx)tst-nodelete-opened.out: $(objpfx)tst-nodelete-opened-lib.so
+$(objpfx)tst-nodelete-opened: $(libdl)
 
 $(objpfx)tst-tlsalign-extern: $(objpfx)tst-tlsalign-vars.o
 $(objpfx)tst-tlsalign-extern-static: $(objpfx)tst-tlsalign-vars.o
diff --git a/elf/dl-open.c b/elf/dl-open.c
index 027c1e0..2db1c02 100644
--- a/elf/dl-open.c
+++ b/elf/dl-open.c
@@ -226,6 +226,12 @@ dl_open_worker (void *a)
   args->map = new = _dl_map_object (call_map, file, lt_loaded, 0,
 				    mode | __RTLD_CALLMAP, args->nsid);
 
+  /* Mark the object as not deletable if the RTLD_NODELETE flags was passed.
+     Do this early so that we don't skip marking the object if it was
+     already loaded.  */
+  if (__glibc_unlikely (mode & RTLD_NODELETE))
+    new->l_flags_1 |= DF_1_NODELETE;
+
   /* If the pointer returned is NULL this means the RTLD_NOLOAD flag is
      set and the object is not already loaded.  */
   if (new == NULL)
@@ -564,11 +570,6 @@ TLS generation counter wrapped!  Please report this."));
       /* It failed.  */
       return;
 
-  /* Mark the object as not deletable if the RTLD_NODELETE flags was
-     passed.  */
-  if (__glibc_unlikely (mode & RTLD_NODELETE))
-    new->l_flags_1 |= DF_1_NODELETE;
-
 #ifndef SHARED
   /* We must be the static _dl_open in libc.a.  A static program that
      has loaded a dynamic object now has competition.  */
diff --git a/elf/tst-nodelete-opened-lib.c b/elf/tst-nodelete-opened-lib.c
new file mode 100644
index 0000000..994702a
--- /dev/null
+++ b/elf/tst-nodelete-opened-lib.c
@@ -0,0 +1,19 @@
+/* Verify that objects opened with RTLD_NODELETE are not unloaded - the DSO.
+   Copyright (C) 2015 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/>.  */
+
+int foo_var = 42;
diff --git a/elf/tst-nodelete-opened.c b/elf/tst-nodelete-opened.c
new file mode 100644
index 0000000..2e54156
--- /dev/null
+++ b/elf/tst-nodelete-opened.c
@@ -0,0 +1,58 @@
+/* Verify that an already opened DSO opened agained with RTLD_NODELETE actually
+   sets the NODELETE flag.
+
+   Copyright (C) 2015 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/>.  */
+
+#include <dlfcn.h>
+#include <stdio.h>
+
+int
+do_test (void)
+{
+  void *h1 = dlopen ("$ORIGIN/tst-nodelete-opened-lib.so", RTLD_LAZY);
+  if (h1 == NULL)
+    {
+      printf ("h1: failed to open DSO: %s\n", dlerror ());
+      return 1;
+    }
+
+  void *h2 = dlopen ("$ORIGIN/tst-nodelete-opened-lib.so",
+		     RTLD_LAZY | RTLD_NODELETE);
+  if (h2 == NULL)
+    {
+      printf ("h2: failed to open DSO: %s\n", dlerror ());
+      return 1;
+    }
+
+  int *foo = dlsym (h2, "foo_var");
+  if (foo == NULL)
+    {
+      printf ("failed to load symbol foo_var: %s\n", dlerror ());
+      return 1;
+    }
+
+  dlclose (h1);
+  dlclose (h2);
+
+  printf ("foo == %d\n", *foo);
+
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
-- 
2.4.3