Bug #11754014: 45549: udf plugin_dir path separator inconsistency

  and cryptic error 1126 message

The problem was that dlopen() related code was using just a subset 
of the path normalization routines used in other places.
Fixed the expansion of the pre-dlopen() behavior for plugins and UDFs
to use a platform-dependent consistent encoding of the paths.
Fixed the error dlopen() error handling to take the correct error message
and strip off the trailing newline character(s).
Fixed tests to do a platform independent replace of directories and to 
account for the traling slash.

1 files changed, 6 insertions, 2 deletions

diff --git a/sql/sql_plugin.cc b/sql/sql_plugin.cc
index 2b801b65a09..4a2d450f373 100644
--- a/sql/sql_plugin.cc
+++ b/sql/sql_plugin.cc
@@ -463,18 +463,22 @@ static st_plugin_dl *plugin_dl_add(const LEX_STRING *dl, int report)
   dlpathlen=
     strxnmov(dlpath, sizeof(dlpath) - 1, opt_plugin_dir, "/", dl->str, NullS) -
     dlpath;
+  (void) unpack_filename(dlpath, dlpath);
   plugin_dl.ref_count= 1;
   /* Open new dll handle */
   if (!(plugin_dl.handle= dlopen(dlpath, RTLD_NOW)))
   {
-    const char *errmsg=dlerror();
+    const char *errmsg;
+    int error_number= dlopen_errno;
+    DLERROR_GENERATE(errmsg, error_number);
+
     if (!strncmp(dlpath, errmsg, dlpathlen))
     { // if errmsg starts from dlpath, trim this prefix.
       errmsg+=dlpathlen;
       if (*errmsg == ':') errmsg++;
       if (*errmsg == ' ') errmsg++;
     }
-    report_error(report, ER_CANT_OPEN_LIBRARY, dlpath, errno, errmsg);
+    report_error(report, ER_CANT_OPEN_LIBRARY, dlpath, error_number, errmsg);
     DBUG_RETURN(0);
   }
   /* Determine interface version */