github.com/minio/minio@v0.0.0-20240328213742-3f72439b8a27/internal/http/check_port_linux.go (about)

     1  //go:build linux
     2  // +build linux
     3  
     4  // Copyright (c) 2015-2023 MinIO, Inc.
     5  //
     6  // This file is part of MinIO Object Storage stack
     7  //
     8  // This program is free software: you can redistribute it and/or modify
     9  // it under the terms of the GNU Affero General Public License as published by
    10  // the Free Software Foundation, either version 3 of the License, or
    11  // (at your option) any later version.
    12  //
    13  // This program is distributed in the hope that it will be useful
    14  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    15  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    16  // GNU Affero General Public License for more details.
    17  //
    18  // You should have received a copy of the GNU Affero General Public License
    19  // along with this program.  If not, see <http://www.gnu.org/licenses/>.
    20  
    21  package http
    22  
    23  import (
    24  	"context"
    25  	"net"
    26  	"syscall"
    27  	"time"
    28  )
    29  
    30  // CheckPortAvailability - check if given host and port is already in use.
    31  // Note: The check method tries to listen on given port and closes it.
    32  // It is possible to have a disconnected client in this tiny window of time.
    33  func CheckPortAvailability(host, port string, opts TCPOptions) (err error) {
    34  	lc := &net.ListenConfig{
    35  		Control: func(network, address string, c syscall.RawConn) error {
    36  			c.Control(func(fdPtr uintptr) {
    37  				if opts.Interface != "" {
    38  					// When interface is specified look for specifically port availability on
    39  					// the specified interface if any.
    40  					_ = syscall.SetsockoptString(int(fdPtr), syscall.SOL_SOCKET, syscall.SO_BINDTODEVICE, opts.Interface)
    41  				}
    42  			})
    43  			return nil
    44  		},
    45  	}
    46  
    47  	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
    48  	defer cancel()
    49  
    50  	l, err := lc.Listen(ctx, "tcp", net.JoinHostPort(host, port))
    51  	if err != nil {
    52  		return err
    53  	}
    54  
    55  	// As we are able to listen on this network, the port is not in use.
    56  	// Close the listener and continue check other networks.
    57  	return l.Close()
    58  }