minio/internal/http/check_port_linux.go

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//go:build linux
// +build linux
// Copyright (c) 2015-2023 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package http
import (
"context"
"net"
"syscall"
"time"
)
// CheckPortAvailability - check if given host and port is already in use.
// Note: The check method tries to listen on given port and closes it.
// It is possible to have a disconnected client in this tiny window of time.
func CheckPortAvailability(host, port string, opts TCPOptions) (err error) {
lc := &net.ListenConfig{
Control: func(network, address string, c syscall.RawConn) error {
c.Control(func(fdPtr uintptr) {
if opts.Interface != "" {
// When interface is specified look for specifically port availability on
// the specified interface if any.
_ = syscall.SetsockoptString(int(fdPtr), syscall.SOL_SOCKET, syscall.SO_BINDTODEVICE, opts.Interface)
}
})
return nil
},
}
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
defer cancel()
l, err := lc.Listen(ctx, "tcp", net.JoinHostPort(host, port))
if err != nil {
return err
}
// As we are able to listen on this network, the port is not in use.
// Close the listener and continue check other networks.
return l.Close()
}