Fix MDEV-7890

storage/connect/ha_connect.cc

@@ -2173,12 +2173,12 @@ int ha_connect::CheckRecord(PGLOBAL g, const uchar *oldbuf, uchar *newbuf)
 /***********************************************************************/
 /*  Return the where clause for remote indexed read.                   */
 /***********************************************************************/
-bool ha_connect::MakeKeyWhere(PGLOBAL g, char *qry, OPVAL op, char *q, 
+bool ha_connect::MakeKeyWhere(PGLOBAL g, PSTRG qry, OPVAL op, char q, 
                                          const void *key, int klen)
 {
   const uchar   *ptr;
   uint           rem, len, stlen; //, prtlen;
-  bool           nq, b= false;
+  bool           nq, oom, b= false;
   Field         *fp;
   KEY           *kfp;
   KEY_PART_INFO *kpart;
@@ -2190,7 +2190,7 @@ bool ha_connect::MakeKeyWhere(PGLOBAL g, char *qry, OPVAL op, char *q,
     return true;
   } // endif key
 
-  strcat(qry, " WHERE (");
+  oom= qry->Append(" WHERE (");
   kfp= &table->key_info[active_index];
   rem= kfp->user_defined_key_parts,
   len= klen,
@@ -2203,24 +2203,26 @@ bool ha_connect::MakeKeyWhere(PGLOBAL g, char *qry, OPVAL op, char *q,
     nq= fp->str_needs_quotes();
 
     if (b)
-      strcat(qry, " AND ");
+      oom|= qry->Append(" AND ");
     else
       b= true;
 
-    strcat(strncat(strcat(qry, q), fp->field_name, strlen(fp->field_name)), q);
+    oom|= qry->Append(q);
+    oom|= qry->Append((PSZ)fp->field_name);
+    oom|= qry->Append(q);
 
     switch (op) {
       case OP_EQ:
       case OP_GT:
       case OP_GE:
-        strcat(qry, GetValStr(op, false));
+        oom|= qry->Append((PSZ)GetValStr(op, false));
         break;
       default:
-        strcat(qry, " ??? ");
+        oom|= qry->Append(" ??? ");
       } // endwitch op
 
     if (nq)
-      strcat(qry, "'");
+      oom|= qry->Append('\'');
 
     if (kpart->key_part_flag & HA_VAR_LENGTH_PART) {
       String varchar;
@@ -2228,17 +2230,17 @@ bool ha_connect::MakeKeyWhere(PGLOBAL g, char *qry, OPVAL op, char *q,
 
       varchar.set_quick((char*) ptr+HA_KEY_BLOB_LENGTH,
                       var_length, &my_charset_bin);
-      strncat(qry, varchar.ptr(), varchar.length());
+      oom|= qry->Append(varchar.ptr(), varchar.length());
     } else {
       char   strbuff[MAX_FIELD_WIDTH];
       String str(strbuff, sizeof(strbuff), kpart->field->charset()), *res;
 
       res= fp->val_str(&str, ptr);
-      strncat(qry, res->ptr(), res->length());
+      oom|= qry->Append(res->ptr(), res->length());
     } // endif flag
 
     if (nq)
-      strcat(qry, "'");
+      oom|= qry->Append('\'');
 
     if (stlen >= len)
       break;
@@ -2251,8 +2253,10 @@ bool ha_connect::MakeKeyWhere(PGLOBAL g, char *qry, OPVAL op, char *q,
     ptr+= stlen - MY_TEST(kpart->null_bit);
     } // endfor kpart
 
-  strcat(qry, ")");
-  return false;
+  if ((oom|= qry->Append(")")))
+    strcpy(g->Message, "Out of memory");
+
+  return oom;
 } // end of MakeKeyWhere
 
 

storage/connect/ha_connect.h

@@ -235,7 +235,7 @@ class ha_connect: public handler
   int      CheckRecord(PGLOBAL g, const uchar *oldbuf, uchar *newbuf);
   int      ReadIndexed(uchar *buf, OPVAL op, const uchar* key= NULL,
                                              uint key_len= 0);
-  bool     MakeKeyWhere(PGLOBAL g, char *qry, OPVAL op, char *q,
+  bool     MakeKeyWhere(PGLOBAL g, PSTRG qry, OPVAL op, char q,
                                    const void *key, int klen);
   inline char *Strz(LEX_STRING &ls); 
 

storage/connect/tabmysql.cpp

@@ -1078,8 +1078,7 @@ bool TDBMYSQL::ReadKey(PGLOBAL g, OPVAL op, const void *key, int len)
     if (Myc.m_Res)
       Myc.FreeResult();
 
-    To_Def->GetHandler()->MakeKeyWhere(g, Query->GetStr(),
-                                       op, "`", key, len);
+    To_Def->GetHandler()->MakeKeyWhere(g, Query, op, '`', key, len);
 
     if (To_CondFil) {
       oom = Query->Append(" AND (");

storage/connect/xobject.cpp

@@ -289,6 +289,34 @@ bool STRING::Set(char *s, uint n)
   return false;
 } // end of Set
 
+/***********************************************************************/
+/*  Append a char* to a STRING.                                          */
+/***********************************************************************/
+bool STRING::Append(const char *s, uint ln)
+{
+  if (!s)
+    return false;
+
+  uint len = Length + ln + 1;
+
+  if (len > Size) {
+    char *p = Realloc(len);
+    
+    if (!p)
+      return true;
+    else if (p != Strp) {
+      strcpy(p, Strp);
+      Strp = p;
+      } // endif p
+
+    } // endif n
+
+  strncpy(Strp + Length, s, ln);
+  Length = len - 1;
+  Strp[Length] = 0;
+  return false;
+} // end of Append
+
 /***********************************************************************/
 /*  Append a PSZ to a STRING.                                          */
 /***********************************************************************/

storage/connect/xobject.h

@@ -134,6 +134,7 @@ class DllExport STRING : public BLOCK {
   inline void   Reset(void) {*Strp = 0;}
          bool   Set(PSZ s);
          bool   Set(char *s, uint n);
+         bool   Append(const char *s, uint ln);
          bool   Append(PSZ s);
          bool   Append(STRING &str);
          bool   Append(char c);