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// Copyright (C) 2022 Andrew Ayer
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
// OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
//
// Except as contained in this notice, the name(s) of the above copyright
// holders shall not be used in advertising or otherwise to promote the
// sale, use or other dealings in this Software without prior written
// authorization.
package listener // import "src.agwa.name/go-listener"
import (
"encoding/json"
"errors"
"fmt"
"net"
"os"
"strconv"
"strings"
"src.agwa.name/go-listener/proxy"
"src.agwa.name/go-listener/unix"
)
func init() {
RegisterListenerType("fd", openFDListener)
RegisterListenerType("fdname", openFDNameListener)
RegisterListenerType("tcp", openTCPListener)
RegisterListenerType("unix", openUnixListener)
RegisterListenerType("proxy", openProxyListener)
}
func openFDListener(params map[string]interface{}, arg string) (net.Listener, error) {
var fdString string
if arg != "" {
fdString = arg
} else if param, ok := params["fd"].(json.Number); ok {
fdString = string(param)
} else if param, ok := params["fd"].(string); ok {
fdString = param
} else {
return nil, errors.New("file descriptor not specified for FD listener")
}
fd, err := strconv.ParseUint(fdString, 10, 64)
if err != nil {
return nil, fmt.Errorf("'%s' is a malformed file descriptor", fdString)
}
file := os.NewFile(uintptr(fd), fdString)
defer file.Close()
return net.FileListener(file)
}
func openFDNameListener(params map[string]interface{}, arg string) (net.Listener, error) {
var name string
if arg != "" {
name = arg
} else if param, ok := params["name"].(string); ok {
name = param
} else {
return nil, errors.New("name not specified for fdname listener")
}
if listenPidStr := os.Getenv("LISTEN_PID"); listenPidStr == "" {
return nil, errors.New("cannot create fdname listener because $LISTEN_PID is not set")
} else if listenPid, err := strconv.Atoi(listenPidStr); err != nil {
return nil, errors.New("cannot create fdname listener because $LISTEN_PID does not contain an integer")
} else if ourPid := os.Getpid(); listenPid != ourPid {
return nil, fmt.Errorf("cannot create fdname listener because $LISTEN_PID (%d) does not match our PID (%d)", listenPid, ourPid)
}
for i, ithname := range strings.Split(os.Getenv("LISTEN_FDNAMES"), ":") {
if ithname == name {
file := os.NewFile(uintptr(3+i), name)
defer file.Close()
return net.FileListener(file)
}
}
return nil, fmt.Errorf("fdname: %q not found in $LISTEN_FDNAMES", name)
}
func openTCPListener(params map[string]interface{}, arg string) (net.Listener, error) {
var ipString string
var portString string
var err error
if arg != "" {
if strings.Contains(arg, ":") {
ipString, portString, err = net.SplitHostPort(arg)
if err != nil {
return nil, fmt.Errorf("TCP listener has invalid argument: %w", err)
}
} else {
portString = arg
}
} else if param, ok := params["address"].(string); ok {
ipString = param
} else if param, ok := params["port"].(json.Number); ok {
portString = string(param)
} else if param, ok := params["port"].(string); ok {
portString = param
}
network := "tcp"
address := new(net.TCPAddr)
if ipString != "" {
address.IP = net.ParseIP(ipString)
if address.IP == nil {
return nil, errors.New("TCP listener has invalid IP address")
}
// Explicitly specify the IP protocol, to ensure that 0.0.0.0
// and :: work as expected (listen only on IPv4 or IPv6 interfaces)
if address.IP.To4() == nil {
network = "tcp6"
} else {
network = "tcp4"
}
}
address.Port, err = strconv.Atoi(portString)
if err != nil {
return nil, fmt.Errorf("TCP listener has invalid port: %w", err)
}
return net.ListenTCP(network, address)
}
func openUnixListener(params map[string]interface{}, arg string) (net.Listener, error) {
var path string
if arg != "" {
path = arg
} else if value, ok := params["path"].(string); ok {
path = value
} else {
return nil, errors.New("path not specified for UNIX listener")
}
return unix.Listen(path, 0666)
}
func openProxyListener(params map[string]interface{}, arg string) (net.Listener, error) {
var inner net.Listener
var err error
if arg != "" {
inner, err = Open(arg)
} else if spec, ok := params["listener"].(map[string]interface{}); ok {
inner, err = OpenJSON(spec)
} else {
return nil, errors.New("inner socket not specified for proxy listener")
}
if err != nil {
return nil, err
}
return proxy.NewListener(inner), nil
}
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