MDEV-3985 crash: uninstall soname 'a'

mysql-test/r/plugin.result

@@ -69,6 +69,8 @@ UNINSTALL PLUGIN EXAMPLE;
 ERROR 42000: PLUGIN EXAMPLE does not exist
 UNINSTALL PLUGIN non_exist;
 ERROR 42000: PLUGIN non_exist does not exist
+UNINSTALL SONAME 'non_exist';
+ERROR 42000: SONAME non_exist.so does not exist
 #
 # Bug#32034: check_func_enum() does not check correct values but set it
 #            to impossible int val

mysql-test/t/plugin.test

@@ -4,14 +4,14 @@
 CREATE TABLE t1(a int) ENGINE=EXAMPLE;
 DROP TABLE t1;
 
-eval INSTALL PLUGIN example SONAME 'ha_example';
+INSTALL PLUGIN example SONAME 'ha_example';
 --replace_regex /\.dll/.so/
 --error 1125
-eval INSTALL PLUGIN EXAMPLE SONAME 'ha_example';
+INSTALL PLUGIN EXAMPLE SONAME 'ha_example';
 
 UNINSTALL PLUGIN example;
 
-eval INSTALL SONAME 'ha_example';
+INSTALL SONAME 'ha_example';
 --replace_column 5 #
 --replace_regex /\.dll/.so/
 --query_vertical select * from information_schema.plugins where plugin_library like 'ha_example%'
@@ -28,7 +28,7 @@ set global example_enum_var= e1;
 show status like 'example%';
 show variables like 'example%';
 
-eval UNINSTALL SONAME 'ha_example';
+UNINSTALL SONAME 'ha_example';
 --replace_column 5 #
 --replace_regex /\.dll/.so/
 --query_vertical select * from information_schema.plugins where plugin_library like 'ha_example%'
@@ -41,12 +41,18 @@ UNINSTALL PLUGIN EXAMPLE;
 --error 1305
 UNINSTALL PLUGIN non_exist;
 
+#
+# MDEV-3985 crash: uninstall soname 'a'
+#
+--replace_regex /\.dll/.so/
+--error 1305
+UNINSTALL SONAME 'non_exist';
 
 --echo #
 --echo # Bug#32034: check_func_enum() does not check correct values but set it
 --echo #            to impossible int val
 --echo #
-eval INSTALL PLUGIN example SONAME 'ha_example';
+INSTALL PLUGIN example SONAME 'ha_example';
 
 SET GLOBAL example_enum_var= e1;
 SET GLOBAL example_enum_var= e2;
@@ -60,7 +66,7 @@ UNINSTALL PLUGIN example;
 #
 # Bug #32757 hang with sql_mode set when setting some global variables
 #
-eval INSTALL PLUGIN example SONAME 'ha_example';
+INSTALL PLUGIN example SONAME 'ha_example';
 
 select @@session.sql_mode into @old_sql_mode;
 

sql/sql_plugin.cc

 /*
    Copyright (c) 2005, 2012, Oracle and/or its affiliates.
-   Copyright (c) 2010, 2011, Monty Program Ab
+   Copyright (c) 2010, 2013, Monty Program Ab
 
    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
@@ -2260,13 +2260,21 @@ bool mysql_uninstall_plugin(THD *thd, const LEX_STRING *name,
   {
     fix_dl_name(thd->mem_root, &dl);
     st_plugin_dl *plugin_dl= plugin_dl_find(&dl);
-    struct st_maria_plugin *plugin;
-    for (plugin= plugin_dl->plugins; plugin->info; plugin++)
+    if (plugin_dl)
+    {
+      for (struct st_maria_plugin *plugin= plugin_dl->plugins;
+           plugin->info; plugin++)
       {
         LEX_STRING str= { const_cast<char*>(plugin->name), strlen(plugin->name) };
         error|= do_uninstall(thd, table, &str);
       }
     }
+    else
+    {
+      my_error(ER_SP_DOES_NOT_EXIST, MYF(0), "SONAME", dl.str);
+      error= true;
+    }
+  }
   reap_plugins();
 
   mysql_mutex_unlock(&LOCK_plugin);