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// 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/.
// Package mysql provides 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"
"sync"
)
// watcher interface is used for context support (From Go 1.8)
type watcher interface {
startWatcher()
}
// MySQLDriver 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 (
dialsLock sync.RWMutex
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) {
dialsLock.Lock()
defer dialsLock.Unlock()
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{
maxAllowedPacket: maxPacketSize,
maxWriteSize: maxPacketSize - 1,
closech: make(chan struct{}),
}
mc.cfg, err = ParseDSN(dsn)
if err != nil {
return nil, err
}
mc.parseTime = mc.cfg.ParseTime
// Connect to Server
dialsLock.RLock()
dial, ok := dials[mc.cfg.Net]
dialsLock.RUnlock()
if 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
}
}
// Call startWatcher for context support (From Go 1.8)
if s, ok := interface{}(mc).(watcher); ok {
s.startWatcher()
}
mc.buf = newBuffer(mc.netConn)
// Set I/O timeouts
mc.buf.timeout = mc.cfg.ReadTimeout
mc.writeTimeout = mc.cfg.WriteTimeout
// 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
}
if mc.cfg.MaxAllowedPacket > 0 {
mc.maxAllowedPacket = mc.cfg.MaxAllowedPacket
} else {
// Get max allowed packet size
maxap, err := mc.getSystemVar("max_allowed_packet")
if err != nil {
mc.Close()
return nil, err
}
mc.maxAllowedPacket = stringToInt(maxap) - 1
}
if mc.maxAllowedPacket < maxPacketSize {
mc.maxWriteSize = mc.maxAllowedPacket
}
// Handle DSN Params
err = mc.handleParams()
if err != nil {
mc.Close()
return nil, err
}
return mc, nil
}
func handleAuthResult(mc *mysqlConn, oldCipher []byte) error {
// Read Result Packet
cipher, 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 CLIENT_PLUGIN_AUTH capability is not supported, no new cipher is
// sent and we have to keep using the cipher sent in the init packet.
if cipher == nil {
cipher = oldCipher
}
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()
} else if mc.cfg.AllowNativePasswords && err == ErrNativePassword {
if err = mc.writeNativeAuthPacket(cipher); err != nil {
return err
}
_, err = mc.readResultOK()
}
return err
}
func init() {
sql.Register("mysql", &MySQLDriver{})
}
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