krb5 commit: Load plugins with RTLD_NODELETE if possible

[Greg Hudson]

https://github.com/krb5/krb5/commit/0f46175d632ae03ab7d4cfba5e62534d31e128e0
commit 0f46175d632ae03ab7d4cfba5e62534d31e128e0
Author: Greg Hudson <ghudson at mit.edu>
Date:   Wed Jun 25 11:41:54 2014 -0400

    Load plugins with RTLD_NODELETE if possible
    
    On platforms which support RTLD_NODELETE, use it to load plugin
    modules.  While using this flag makes plugins stay in the process map
    after libkrb5/libgssapi_krb5 are unloaded, it solves several problems:
    
    1. It prevents plugin modules which link against OpenSSL (PKINIT and
    k5tls) from repeatedly initializing instances of libssl or libcrypto,
    leaking heap memory each time.  This is only an issue because we
    cannot safely uninitialize OpenSSL.
    
    2. It prevents finalization ordering issues from causing a process
    crash when unloading libgssapi_krb5 (issue #7135).
    
    3. It makes memory leak tracing with valgrind easier.
    
    ticket: 7947 (new)

 src/util/support/plugins.c |   19 ++++++++++++++-----
 1 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/src/util/support/plugins.c b/src/util/support/plugins.c
index a04dfc3..ca4b128 100644
--- a/src/util/support/plugins.c
+++ b/src/util/support/plugins.c
@@ -45,6 +45,20 @@
 
 #include "k5-platform.h"
 
+#if USE_DLOPEN
+#ifdef RTLD_GROUP
+#define GROUP RTLD_GROUP
+#else
+#define GROUP 0
+#endif
+#ifdef RTLD_NODELETE
+#define NODELETE RTLD_NODELETE
+#else
+#define NODELETE 0
+#endif
+#define PLUGIN_DLOPEN_FLAGS (RTLD_NOW | RTLD_LOCAL | GROUP | NODELETE)
+#endif
+
 #if USE_DLOPEN && USE_CFBUNDLE
 #include <CoreFoundation/CoreFoundation.h>
 
@@ -257,11 +271,6 @@ krb5int_open_plugin (const char *filepath, struct plugin_file_handle **h, struct
         }
 #endif /* USE_CFBUNDLE */
 
-#ifdef RTLD_GROUP
-#define PLUGIN_DLOPEN_FLAGS (RTLD_NOW | RTLD_LOCAL | RTLD_GROUP)
-#else
-#define PLUGIN_DLOPEN_FLAGS (RTLD_NOW | RTLD_LOCAL)
-#endif
         if (!err) {
             handle = dlopen(filepath, PLUGIN_DLOPEN_FLAGS);
             if (handle == NULL) {