1 files changed, 88 insertions, 0 deletions
diff --git a/sql/debug.cc b/sql/debug.cc
new file mode 100644
index 00000000..a0e2340e
--- /dev/null
+++ b/sql/debug.cc
@@ -0,0 +1,88 @@
+/* Copyright (c) 2021, MariaDB Corporation.
+
+   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
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
+
+#include "mariadb.h"
+#include "sql_class.h"
+#include "debug.h"
+
+/**
+   Debug utility to do crash after a set number of executions
+
+   The user variable, either @debug_crash_counter or @debug_error_counter,
+   is decremented each time debug_crash() or debug_simulate_error is called
+   if the keyword is set with @@debug_push, like
+   @@debug_push="d+frm_data_type_info_emulate"
+
+   If the variable is not set or is not an integer it will be ignored.
+*/
+
+#ifndef DBUG_OFF
+
+static const LEX_CSTRING debug_crash_counter=
+{ STRING_WITH_LEN("debug_crash_counter") };
+static const LEX_CSTRING debug_error_counter=
+{ STRING_WITH_LEN("debug_error_counter") };
+
+static bool debug_decrement_counter(const LEX_CSTRING *name)
+{
+  THD *thd= current_thd;
+  user_var_entry *entry= (user_var_entry*)
+    my_hash_search(&thd->user_vars, (uchar*) name->str, name->length);
+  if (!entry || entry->type != INT_RESULT || ! entry->value)
+    return 0;
+  (*(ulonglong*) entry->value)= (*(ulonglong*) entry->value)-1;
+  return !*(ulonglong*) entry->value;
+}
+
+void debug_crash_here(const char *keyword)
+{
+  DBUG_ENTER("debug_crash_here");
+  DBUG_PRINT("enter", ("keyword: %s", keyword));
+
+  DBUG_EXECUTE_IF(keyword,
+                  if (debug_decrement_counter(&debug_crash_counter))
+                  {
+                    my_printf_error(ER_INTERNAL_ERROR,
+                                    "Crashing at %s",
+                                    MYF(ME_ERROR_LOG | ME_NOTE), keyword);
+                    DBUG_SUICIDE();
+                  });
+  DBUG_VOID_RETURN;
+}
+
+/*
+  This can be used as debug_counter to simulate an error at a specific
+  position.
+
+  Typical usage would be
+  if (debug_simualte_error("keyword"))
+    error= 1;
+*/
+
+bool debug_simulate_error(const char *keyword, uint error)
+{
+  DBUG_ENTER("debug_crash_here");
+  DBUG_PRINT("enter", ("keyword: %s", keyword));
+  DBUG_EXECUTE_IF(keyword,
+                  if (debug_decrement_counter(&debug_error_counter))
+                  {
+                    my_printf_error(error,
+                                    "Simulating error for '%s'",
+                                    MYF(ME_ERROR_LOG), keyword);
+                    DBUG_RETURN(1);
+                  });
+  DBUG_RETURN(0);
+}
+#endif /* DBUG_OFF */