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bee/vendor/github.com/go-sql-driver/mysql/driver.go
2016-12-05 23:07:45 +08:00

162 lines
4.3 KiB
Go

// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at http://mozilla.org/MPL/2.0/.
// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
//
// The driver should be used via the database/sql package:
//
// import "database/sql"
// import _ "github.com/go-sql-driver/mysql"
//
// db, err := sql.Open("mysql", "user:password@/dbname")
//
// See https://github.com/go-sql-driver/mysql#usage for details
package mysql
import (
"database/sql"
"database/sql/driver"
"net"
)
// This struct is exported to make the driver directly accessible.
// In general the driver is used via the database/sql package.
type MySQLDriver struct{}
// DialFunc is a function which can be used to establish the network connection.
// Custom dial functions must be registered with RegisterDial
type DialFunc func(addr string) (net.Conn, error)
var dials map[string]DialFunc
// RegisterDial registers a custom dial function. It can then be used by the
// network address mynet(addr), where mynet is the registered new network.
// addr is passed as a parameter to the dial function.
func RegisterDial(net string, dial DialFunc) {
if dials == nil {
dials = make(map[string]DialFunc)
}
dials[net] = dial
}
// Open new Connection.
// See https://github.com/go-sql-driver/mysql#dsn-data-source-name for how
// the DSN string is formated
func (d MySQLDriver) Open(dsn string) (driver.Conn, error) {
var err error
// New mysqlConn
mc := &mysqlConn{
maxPacketAllowed: maxPacketSize,
maxWriteSize: maxPacketSize - 1,
}
mc.cfg, err = parseDSN(dsn)
if err != nil {
return nil, err
}
// Connect to Server
if dial, ok := dials[mc.cfg.net]; ok {
mc.netConn, err = dial(mc.cfg.addr)
} else {
nd := net.Dialer{Timeout: mc.cfg.timeout}
mc.netConn, err = nd.Dial(mc.cfg.net, mc.cfg.addr)
}
if err != nil {
return nil, err
}
// Enable TCP Keepalives on TCP connections
if tc, ok := mc.netConn.(*net.TCPConn); ok {
if err := tc.SetKeepAlive(true); err != nil {
// Don't send COM_QUIT before handshake.
mc.netConn.Close()
mc.netConn = nil
return nil, err
}
}
mc.buf = newBuffer(mc.netConn)
// Reading Handshake Initialization Packet
cipher, err := mc.readInitPacket()
if err != nil {
mc.cleanup()
return nil, err
}
// Send Client Authentication Packet
if err = mc.writeAuthPacket(cipher); err != nil {
mc.cleanup()
return nil, err
}
// Handle response to auth packet, switch methods if possible
if err = handleAuthResult(mc, cipher); err != nil {
// Authentication failed and MySQL has already closed the connection
// (https://dev.mysql.com/doc/internals/en/authentication-fails.html).
// Do not send COM_QUIT, just cleanup and return the error.
mc.cleanup()
return nil, err
}
// Get max allowed packet size
maxap, err := mc.getSystemVar("max_allowed_packet")
if err != nil {
mc.Close()
return nil, err
}
mc.maxPacketAllowed = stringToInt(maxap) - 1
if mc.maxPacketAllowed < maxPacketSize {
mc.maxWriteSize = mc.maxPacketAllowed
}
// Handle DSN Params
err = mc.handleParams()
if err != nil {
mc.Close()
return nil, err
}
return mc, nil
}
func handleAuthResult(mc *mysqlConn, cipher []byte) error {
// Read Result Packet
err := mc.readResultOK()
if err == nil {
return nil // auth successful
}
if mc.cfg == nil {
return err // auth failed and retry not possible
}
// Retry auth if configured to do so.
if mc.cfg.allowOldPasswords && err == ErrOldPassword {
// Retry with old authentication method. Note: there are edge cases
// where this should work but doesn't; this is currently "wontfix":
// https://github.com/go-sql-driver/mysql/issues/184
if err = mc.writeOldAuthPacket(cipher); err != nil {
return err
}
err = mc.readResultOK()
} else if mc.cfg.allowCleartextPasswords && err == ErrCleartextPassword {
// Retry with clear text password for
// http://dev.mysql.com/doc/refman/5.7/en/cleartext-authentication-plugin.html
// http://dev.mysql.com/doc/refman/5.7/en/pam-authentication-plugin.html
if err = mc.writeClearAuthPacket(); err != nil {
return err
}
err = mc.readResultOK()
}
return err
}
func init() {
sql.Register("mysql", &MySQLDriver{})
}