From e7924df06ace8937b3d4f42728f92d1bf4032990 Mon Sep 17 00:00:00 2001
From: Brian Lopez <seniorlopez@gmail.com>
Date: Tue, 14 Sep 2010 22:27:07 -0700
Subject: [PATCH] make sure we only attempt to close/free the MYSQL pointer
 once

---
 ext/mysql2/client.c | 33 +++++++++++++++++++--------------
 ext/mysql2/client.h |  1 +
 2 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/ext/mysql2/client.c b/ext/mysql2/client.c
index 44e87f3..395728b 100644
--- a/ext/mysql2/client.c
+++ b/ext/mysql2/client.c
@@ -8,8 +8,8 @@ static VALUE intern_encoding_from_charset;
 static ID sym_id, sym_version, sym_async, sym_symbolize_keys, sym_as, sym_array;
 static ID intern_merge, intern_error_number_eql, intern_sql_state_eql;
 
-#define REQUIRE_OPEN_DB(_ctxt) \
-  if(!_ctxt->net.vio) { \
+#define REQUIRE_OPEN_DB(wrapper) \
+  if(wrapper->closed || !wrapper->client->net.vio) { \
     rb_raise(cMysql2Error, "closed MySQL connection"); \
     return Qnil; \
   }
@@ -130,14 +130,18 @@ static void rb_mysql_client_free(void * ptr) {
   }
 
   /* It's safe to call mysql_close() on an already closed connection. */
-  mysql_close(wrapper->client);
+  if (!wrapper->closed) {
+    mysql_close(wrapper->client);
+  }
   xfree(ptr);
 }
 
 static VALUE nogvl_close(void * ptr) {
-  MYSQL *client = (MYSQL *)ptr;
-  mysql_close(client);
-  client->net.fd = -1;
+  mysql_client_wrapper *wrapper = ptr;
+  if (!wrapper->closed) {
+    mysql_close(wrapper->client);
+    wrapper->closed = 1;
+  }
   return Qnil;
 }
 
@@ -147,6 +151,7 @@ static VALUE allocate(VALUE klass) {
   obj = Data_Make_Struct(klass, mysql_client_wrapper, rb_mysql_client_mark, rb_mysql_client_free, wrapper);
   wrapper->encoding = Qnil;
   wrapper->active = 0;
+  wrapper->closed = 0;
   return obj;
 }
 
@@ -180,7 +185,7 @@ static VALUE rb_connect(VALUE self, VALUE user, VALUE pass, VALUE host, VALUE po
 static VALUE rb_mysql_client_close(VALUE self) {
   GET_CLIENT(self);
 
-  rb_thread_blocking_region(nogvl_close, wrapper->client, RUBY_UBF_IO, 0);
+  rb_thread_blocking_region(nogvl_close, wrapper, RUBY_UBF_IO, 0);
 
   return Qnil;
 }
@@ -223,7 +228,7 @@ static VALUE rb_mysql_client_async_result(VALUE self) {
   MYSQL_RES * result;
   GET_CLIENT(self);
 
-  REQUIRE_OPEN_DB(wrapper->client);
+  REQUIRE_OPEN_DB(wrapper);
   if (rb_thread_blocking_region(nogvl_read_query_result, wrapper->client, RUBY_UBF_IO, 0) == Qfalse) {
     // an error occurred, mark this connection inactive
     MARK_CONN_INACTIVE(self);
@@ -262,7 +267,7 @@ static VALUE rb_mysql_client_query(int argc, VALUE * argv, VALUE self) {
   VALUE opts, defaults;
   GET_CLIENT(self);
 
-  REQUIRE_OPEN_DB(wrapper->client);
+  REQUIRE_OPEN_DB(wrapper);
   args.mysql = wrapper->client;
 
   // see if this connection is still waiting on a result from a previous query
@@ -340,7 +345,7 @@ static VALUE rb_mysql_client_escape(VALUE self, VALUE str) {
   oldLen = RSTRING_LEN(str);
   newStr = rb_str_new(0, oldLen*2+1);
 
-  REQUIRE_OPEN_DB(wrapper->client);
+  REQUIRE_OPEN_DB(wrapper);
   newLen = mysql_real_escape_string(wrapper->client, RSTRING_PTR(newStr), StringValuePtr(str), oldLen);
   if (newLen == oldLen) {
     // no need to return a new ruby string if nothing changed
@@ -385,7 +390,7 @@ static VALUE rb_mysql_client_server_info(VALUE self) {
   rb_encoding *conn_enc = rb_to_encoding(wrapper->encoding);
 #endif
 
-  REQUIRE_OPEN_DB(wrapper->client);
+  REQUIRE_OPEN_DB(wrapper);
 
   version = rb_hash_new();
   rb_hash_aset(version, sym_id, LONG2FIX(mysql_get_server_version(wrapper->client)));
@@ -402,19 +407,19 @@ static VALUE rb_mysql_client_server_info(VALUE self) {
 
 static VALUE rb_mysql_client_socket(VALUE self) {
   GET_CLIENT(self);
-  REQUIRE_OPEN_DB(wrapper->client);
+  REQUIRE_OPEN_DB(wrapper);
   return INT2NUM(wrapper->client->net.fd);
 }
 
 static VALUE rb_mysql_client_last_id(VALUE self) {
   GET_CLIENT(self);
-  REQUIRE_OPEN_DB(wrapper->client);
+  REQUIRE_OPEN_DB(wrapper);
   return ULL2NUM(mysql_insert_id(wrapper->client));
 }
 
 static VALUE rb_mysql_client_affected_rows(VALUE self) {
   GET_CLIENT(self);
-  REQUIRE_OPEN_DB(wrapper->client);
+  REQUIRE_OPEN_DB(wrapper);
   return ULL2NUM(mysql_affected_rows(wrapper->client));
 }
 
diff --git a/ext/mysql2/client.h b/ext/mysql2/client.h
index 781ccda..d5c2993 100644
--- a/ext/mysql2/client.h
+++ b/ext/mysql2/client.h
@@ -34,6 +34,7 @@ void init_mysql2_client();
 typedef struct {
   VALUE encoding;
   short int active;
+  short int closed;
   MYSQL *client;
 } mysql_client_wrapper;