From b6bd1998502ca53a33f0d28a9f5df0c5cbc0b5f1 Mon Sep 17 00:00:00 2001
From: Annamalai Gurusami <annamalai.gurusami@oracle.com>
Date: Thu, 21 Mar 2013 11:40:43 +0530
Subject: Bug #16051728 SERVER CRASHES IN ADD_IDENTIFIER ON CONCURRENT ALTER
 TABLE AND SHOW ENGINE INNOD

Problem:

The purpose of explain_filename() is to provide useful additional
information regarding the partitions given the filename.  This function
was returning an error when it was not able to parse the given filename.
For example, within InnoDB, temporary files are created with #sql-
prefix.  But this function was not able to parse it correctly.

Solution:

It is not an error, if explain_filename() could not parse the given
filename.  If there is no partition information to explain, then silently
return from the function.

rb#1940 approved by mattiasj
---
 sql/sql_table.cc | 56 ++++++++++++++++++++------------------------------------
 1 file changed, 20 insertions(+), 36 deletions(-)

(limited to 'sql/sql_table.cc')

diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index cf4d7a9d955..a65d2f0345b 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -198,7 +198,6 @@ uint explain_filename(THD* thd,
                       uint to_length,
                       enum_explain_filename_mode explain_mode)
 {
-  uint res= 0;
   char *to_p= to;
   char *end_p= to_p + to_length;
   const char *db_name= NULL;
@@ -209,7 +208,8 @@ uint explain_filename(THD* thd,
   int  part_name_len= 0;
   const char *subpart_name= NULL;
   int  subpart_name_len= 0;
-  enum enum_file_name_type {NORMAL, TEMP, RENAMED} name_type= NORMAL;
+  enum enum_part_name_type {NORMAL, TEMP, RENAMED} part_type= NORMAL;
+
   const char *tmp_p;
   DBUG_ENTER("explain_filename");
   DBUG_PRINT("enter", ("from '%s'", from));
@@ -228,17 +228,18 @@ uint explain_filename(THD* thd,
     table_name= tmp_p;
   }
   tmp_p= table_name;
-  while (!res && (tmp_p= strchr(tmp_p, '#')))
+  /* Look if there are partition tokens in the table name. */
+  while ((tmp_p= strchr(tmp_p, '#')))
   {
     tmp_p++;
     switch (tmp_p[0]) {
     case 'P':
     case 'p':
       if (tmp_p[1] == '#')
+      {
         part_name= tmp_p + 2;
-      else
-        res= 1;
-      tmp_p+= 2;
+        tmp_p+= 2;
+      }
       break;
     case 'S':
     case 's':
@@ -248,49 +249,32 @@ uint explain_filename(THD* thd,
         subpart_name= tmp_p + 3;
 	tmp_p+= 3;
       }
-      else if ((tmp_p[1] == 'Q' || tmp_p[1] == 'q') &&
-               (tmp_p[2] == 'L' || tmp_p[2] == 'l') &&
-                tmp_p[3] == '-')
-      {
-        name_type= TEMP;
-        tmp_p+= 4; /* sql- prefix found */
-      }
-      else
-        res= 2;
       break;
     case 'T':
     case 't':
       if ((tmp_p[1] == 'M' || tmp_p[1] == 'm') &&
           (tmp_p[2] == 'P' || tmp_p[2] == 'p') &&
           tmp_p[3] == '#' && !tmp_p[4])
-        name_type= TEMP;
-      else
-        res= 3;
-      tmp_p+= 4;
+      {
+        part_type= TEMP;
+        tmp_p+= 4;
+      }
       break;
     case 'R':
     case 'r':
       if ((tmp_p[1] == 'E' || tmp_p[1] == 'e') &&
           (tmp_p[2] == 'N' || tmp_p[2] == 'n') &&
           tmp_p[3] == '#' && !tmp_p[4])
-        name_type= RENAMED;
-      else
-        res= 4;
-      tmp_p+= 4;
+      {
+        part_type= RENAMED;
+        tmp_p+= 4;
+      }
       break;
     default:
-      res= 5;
+      /* Not partition name part. */
+      ;
     }
   }
-  if (res)
-  {
-    /* Better to give something back if we fail parsing, than nothing at all */
-    DBUG_PRINT("info", ("Error in explain_filename: %u", res));
-    sql_print_warning("Invalid (old?) table or database name '%s'", from);
-    DBUG_RETURN(my_snprintf(to, to_length,
-                            "<result %u when explaining filename '%s'>",
-                            res, from));
-  }
   if (part_name)
   {
     table_name_len= part_name - table_name - 3;
@@ -298,7 +282,7 @@ uint explain_filename(THD* thd,
       subpart_name_len= strlen(subpart_name);
     else
       part_name_len= strlen(part_name);
-    if (name_type != NORMAL)
+    if (part_type != NORMAL)
     {
       if (subpart_name)
         subpart_name_len-= 5;
@@ -340,9 +324,9 @@ uint explain_filename(THD* thd,
       to_p= strnmov(to_p, " ", end_p - to_p);
     else
       to_p= strnmov(to_p, ", ", end_p - to_p);
-    if (name_type != NORMAL)
+    if (part_type != NORMAL)
     {
-      if (name_type == TEMP)
+      if (part_type == TEMP)
         to_p= strnmov(to_p, ER_THD_OR_DEFAULT(thd, ER_TEMPORARY_NAME),
                       end_p - to_p);
       else
-- 
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