krb5 commit: Trace plugin module loading errors

[Greg Hudson]

https://github.com/krb5/krb5/commit/e362c356eafb49a9d90a4f20c6668682d4f50222
commit e362c356eafb49a9d90a4f20c6668682d4f50222
Author: Greg Hudson <ghudson at mit.edu>
Date:   Sat Jun 27 01:40:21 2020 -0400

    Trace plugin module loading errors
    
    Add trace messages when dlopen() or dlsym() fails when loading a
    plugin module.
    
    ticket: 8922 (new)

 src/include/k5-trace.h    |    5 +++++
 src/lib/krb5/krb/plugin.c |   14 ++++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/include/k5-trace.h b/src/include/k5-trace.h
index 1da53db..853a367 100644
--- a/src/include/k5-trace.h
+++ b/src/include/k5-trace.h
@@ -299,6 +299,11 @@ void krb5int_trace(krb5_context context, const char *fmt, ...);
 #define TRACE_NEGOEX_OUTGOING(c, seqnum, typestr, info)                 \
     TRACE(c, "NegoEx sending [{int}]{str}: {str}", (int)seqnum, typestr, info)
 
+#define TRACE_PLUGIN_LOAD_FAIL(c, modname, err)                         \
+    TRACE(c, "Error loading plugin module {str}: {kerr}", modname, err)
+#define TRACE_PLUGIN_LOOKUP_FAIL(c, modname, err)                       \
+    TRACE(c, "Error initializing module {str}: {kerr}", modname, err)
+
 #define TRACE_PREAUTH_CONFLICT(c, name1, name2, patype)                 \
     TRACE(c, "Preauth module {str} conflicts with module {str} for pa " \
           "type {patype}", name1, name2, patype)
diff --git a/src/lib/krb5/krb/plugin.c b/src/lib/krb5/krb/plugin.c
index 5761de0..3bb7a38 100644
--- a/src/lib/krb5/krb/plugin.c
+++ b/src/lib/krb5/krb/plugin.c
@@ -352,6 +352,7 @@ static void
 load_if_needed(krb5_context context, struct plugin_mapping *map,
                const char *iname)
 {
+    krb5_error_code ret;
     char *symname = NULL;
     struct plugin_file_handle *handle = NULL;
     void (*initvt_fn)();
@@ -360,10 +361,19 @@ load_if_needed(krb5_context context, struct plugin_mapping *map,
         return;
     if (asprintf(&symname, "%s_%s_initvt", iname, map->modname) < 0)
         return;
-    if (krb5int_open_plugin(map->dyn_path, &handle, &context->err))
+
+    ret = krb5int_open_plugin(map->dyn_path, &handle, &context->err);
+    if (ret) {
+        TRACE_PLUGIN_LOAD_FAIL(context, map->modname, ret);
         goto err;
-    if (krb5int_get_plugin_func(handle, symname, &initvt_fn, &context->err))
+    }
+
+    ret = krb5int_get_plugin_func(handle, symname, &initvt_fn, &context->err);
+    if (ret) {
+        TRACE_PLUGIN_LOOKUP_FAIL(context, map->modname, ret);
         goto err;
+    }
+
     free(symname);
     map->dyn_handle = handle;
     map->module = (krb5_plugin_initvt_fn)initvt_fn;