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.

include/my_global.h

@@ -1364,11 +1364,31 @@ do { doubleget_union _tmp; \
 
 #ifndef HAVE_DLERROR
 #ifdef _WIN32
+#define DLERROR_GENERATE(errmsg, error_number) \
+  char win_errormsg[2048]; \
+  if(FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, \
+                   0, error_number, 0, win_errormsg, 2048, NULL)) \
+  { \
+    char *ptr; \
+    for (ptr= &win_errormsg[0] + strlen(win_errormsg) - 1; \
+         ptr >= &win_errormsg[0] && strchr("\r\n\t\0x20", *ptr); \
+         ptr--) \
+      *ptr= 0; \
+    errmsg= win_errormsg; \
+  } \
+  else \
+    errmsg= ""
 #define dlerror() ""
-#else
+#define dlopen_errno GetLastError()
+#else /* _WIN32 */
 #define dlerror() "No support for dynamic loading (static build?)"
-#endif
-#endif
+#define DLERROR_GENERATE(errmsg, error_number) errmsg= dlerror()
+#define dlopen_errno errno
+#endif /* _WIN32 */
+#else /* HAVE_DLERROR */
+#define DLERROR_GENERATE(errmsg, error_number) errmsg= dlerror()
+#define dlopen_errno errno
+#endif /* HAVE_DLERROR */
 
 
 /*

mysql-test/suite/sys_vars/r/character_sets_dir_basic.result

 select @@global.character_sets_dir;
 @@global.character_sets_dir
-MYSQL_CHARSETSDIR/
+MYSQL_CHARSETSDIR
 select @@session.character_sets_dir;
 ERROR HY000: Variable 'character_sets_dir' is a GLOBAL variable
 show global variables like 'character_sets_dir';
 Variable_name	Value
-character_sets_dir	MYSQL_CHARSETSDIR/
+character_sets_dir	MYSQL_CHARSETSDIR
 show session variables like 'character_sets_dir';
 Variable_name	Value
-character_sets_dir	MYSQL_CHARSETSDIR/
+character_sets_dir	MYSQL_CHARSETSDIR
 select * from information_schema.global_variables where variable_name='character_sets_dir';
 VARIABLE_NAME	VARIABLE_VALUE
-CHARACTER_SETS_DIR	MYSQL_CHARSETSDIR/
+CHARACTER_SETS_DIR	MYSQL_CHARSETSDIR
 select * from information_schema.session_variables where variable_name='character_sets_dir';
 VARIABLE_NAME	VARIABLE_VALUE
-CHARACTER_SETS_DIR	MYSQL_CHARSETSDIR/
+CHARACTER_SETS_DIR	MYSQL_CHARSETSDIR
 set global character_sets_dir="foo";
 ERROR HY000: Variable 'character_sets_dir' is a read only variable
 set session character_sets_dir="foo";

mysql-test/suite/sys_vars/r/plugin_dir_basic.result

 select @@global.plugin_dir;
 @@global.plugin_dir
-MYSQL_TMP_DIR
+MYSQL_TMP_DIR/
 select @@session.plugin_dir;
 ERROR HY000: Variable 'plugin_dir' is a GLOBAL variable
 show global variables like 'plugin_dir';
 Variable_name	Value
-plugin_dir	MYSQL_TMP_DIR
+plugin_dir	MYSQL_TMP_DIR/
 show session variables like 'plugin_dir';
 Variable_name	Value
-plugin_dir	MYSQL_TMP_DIR
+plugin_dir	MYSQL_TMP_DIR/
 select * from information_schema.global_variables where variable_name='plugin_dir';
 VARIABLE_NAME	VARIABLE_VALUE
-PLUGIN_DIR	MYSQL_TMP_DIR
+PLUGIN_DIR	MYSQL_TMP_DIR/
 select * from information_schema.session_variables where variable_name='plugin_dir';
 VARIABLE_NAME	VARIABLE_VALUE
-PLUGIN_DIR	MYSQL_TMP_DIR
+PLUGIN_DIR	MYSQL_TMP_DIR/
 set global plugin_dir=1;
 ERROR HY000: Variable 'plugin_dir' is a read only variable
 set session plugin_dir=1;

mysql-test/suite/sys_vars/t/character_sets_dir_basic.test

 #
 # show the global and session values;
 #
---replace_result $MYSQL_CHARSETSDIR MYSQL_CHARSETSDIR
+
+# workaround to adjust for the directory separators being different in 
+# different OSes : slash on unixes and backslash or slash on windows.
+# TODO: fix with a proper comparison in mysqltest
+let $rcd= `SELECT REPLACE('$MYSQL_CHARSETSDIR', '\\\\\', '.')`;
+let $rcd= `SELECT REPLACE('$rcd', '/', '.')`;
+let $regex_charsetdir= `SELECT '/$rcd[\\\\\/\\\\\]/MYSQL_CHARSETSDIR/'`;
+
+--replace_regex $regex_charsetdir
 select @@global.character_sets_dir;
+
 --error ER_INCORRECT_GLOBAL_LOCAL_VAR
 select @@session.character_sets_dir;
---replace_result $MYSQL_CHARSETSDIR MYSQL_CHARSETSDIR
+--replace_regex $regex_charsetdir
 show global variables like 'character_sets_dir';
---replace_result $MYSQL_CHARSETSDIR MYSQL_CHARSETSDIR
+--replace_regex $regex_charsetdir
 show session variables like 'character_sets_dir';
---replace_result $MYSQL_CHARSETSDIR MYSQL_CHARSETSDIR
+--replace_regex $regex_charsetdir
 select * from information_schema.global_variables where variable_name='character_sets_dir';
---replace_result $MYSQL_CHARSETSDIR MYSQL_CHARSETSDIR
+--replace_regex $regex_charsetdir
 select * from information_schema.session_variables where variable_name='character_sets_dir';
 
 #

sql/mysqld.cc

@@ -7608,8 +7608,10 @@ static int fix_paths(void)
   (void) my_load_path(mysql_home,mysql_home,""); // Resolve current dir
   (void) my_load_path(mysql_real_data_home,mysql_real_data_home,mysql_home);
   (void) my_load_path(pidfile_name, pidfile_name_ptr, mysql_real_data_home);
-  (void) my_load_path(opt_plugin_dir, opt_plugin_dir_ptr ? opt_plugin_dir_ptr :
-                                      get_relative_path(PLUGINDIR), mysql_home);
+
+  convert_dirname(opt_plugin_dir, opt_plugin_dir_ptr ? opt_plugin_dir_ptr : 
+                                  get_relative_path(PLUGINDIR), NullS);
+  (void) my_load_path(opt_plugin_dir, opt_plugin_dir, mysql_home);
   opt_plugin_dir_ptr= opt_plugin_dir;
 
   my_realpath(mysql_unpacked_real_data_home, mysql_real_data_home, MYF(0));

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 */

sql/sql_udf.cc

@@ -221,10 +221,15 @@ void udf_init()
       char dlpath[FN_REFLEN];
       strxnmov(dlpath, sizeof(dlpath) - 1, opt_plugin_dir, "/", tmp->dl,
                NullS);
+      (void) unpack_filename(dlpath, dlpath);
       if (!(dl= dlopen(dlpath, RTLD_NOW)))
       {
+	const char *errmsg;
+	int error_number= dlopen_errno;
+	DLERROR_GENERATE(errmsg, error_number);
+
 	/* Print warning to log */
-        sql_print_error(ER(ER_CANT_OPEN_LIBRARY), tmp->dl, errno, dlerror());
+        sql_print_error(ER(ER_CANT_OPEN_LIBRARY), tmp->dl, error_number, errmsg);
 	/* Keep the udf in the hash so that we can remove it later */
 	continue;
       }
@@ -469,12 +474,18 @@ int mysql_create_function(THD *thd,udf_func *udf)
   {
     char dlpath[FN_REFLEN];
     strxnmov(dlpath, sizeof(dlpath) - 1, opt_plugin_dir, "/", udf->dl, NullS);
+    (void) unpack_filename(dlpath, dlpath);
+
     if (!(dl = dlopen(dlpath, RTLD_NOW)))
     {
+      const char *errmsg;
+      int error_number= dlopen_errno;
+      DLERROR_GENERATE(errmsg, error_number);
+
       DBUG_PRINT("error",("dlopen of %s failed, error: %d (%s)",
-                          udf->dl, errno, dlerror()));
+                          udf->dl, error_number, errmsg));
       my_error(ER_CANT_OPEN_LIBRARY, MYF(0),
-               udf->dl, errno, dlerror());
+               udf->dl, error_number, errmsg);
       goto err;
     }
     new_dl=1;