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// Copyright (C) 2015 Luke Shumaker <lukeshu@sbcglobal.net>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
// 02110-1301 USA
// Package nslcd_systemd does the legwork for implementing a systemd
// socket-activated nslcd server.
//
// You just need to implement the Backend interface, then pass it to
// Main, which will return the exit code for the process. Everything
// but the backend is taken care of for you!
//
// package main
//
// import "nslcd/systemd"
//
// func main() {
// backend := ...
// os.Exit(int(nslcd_systemd.Main(backend)))
// }
package nslcd_systemd
import (
"fmt"
"lukeshu.com/git/go/libnslcd.git/proto/server"
"lukeshu.com/git/go/libsystemd.git/sd_daemon"
"lukeshu.com/git/go/libsystemd.git/sd_daemon/logger"
"lukeshu.com/git/go/libsystemd.git/sd_daemon/lsb"
"net"
"os"
"os/signal"
"sync"
"syscall"
)
type Backend interface {
nslcd_server.Backend
Init() error
Reload() error
Close()
}
func get_socket() (socket net.Listener, err error) {
socket = nil
err = nil
fds := sd.ListenFds(true)
if fds == nil {
err = fmt.Errorf("Failed to aquire sockets from systemd")
return
}
if len(fds) != 1 {
err = fmt.Errorf("Wrong number of sockets from systemd: expected %d but got %d", 1, len(fds))
return
}
socket, err = net.FileListener(fds[0])
fds[0].Close()
return
}
func getpeercred(conn *net.UnixConn) (cred syscall.Ucred, err error) {
file, err := conn.File()
if err != nil {
return
}
defer file.Close()
_cred, err := syscall.GetsockoptUcred(int(file.Fd()), syscall.SOL_SOCKET, syscall.SO_PEERCRED)
cred = *_cred
return
}
func handler(conn *net.UnixConn, backend nslcd_server.Backend) {
defer conn.Close()
cred, err := getpeercred(conn)
if err != nil {
logger.Debug("Connection from unknown client")
} else {
logger.Debug("Connection from pid=%v uid=%v gid=%v",
cred.Pid, cred.Uid, cred.Gid)
}
err = nslcd_server.HandleRequest(backend, conn, conn, cred)
if err != nil {
logger.Notice("Error while handling request: %v", err)
}
}
func Main(backend Backend) uint8 {
var err error = nil
sigs := make(chan os.Signal)
signal.Notify(sigs, syscall.SIGTERM, syscall.SIGHUP)
disable_nss_module()
err = backend.Init()
if err != nil {
logger.Err("Could not initialize backend: %v", err)
sd.Notify(false, "STOPPING=1")
return lsb.EXIT_FAILURE
}
defer backend.Close()
socket, err := get_socket()
if err != nil {
logger.Err("%v", err)
sd.Notify(false, "STOPPING=1")
return lsb.EXIT_NOTRUNNING
}
defer socket.Close()
sock := make(chan *net.UnixConn)
go func() {
defer lsb.Recover()
for {
conn, err := socket.Accept()
if err != nil {
logger.Notice("%v", err)
}
if conn != nil {
sock <- conn.(*net.UnixConn)
}
}
}()
var wg sync.WaitGroup
defer wg.Wait()
defer sd.Notify(false, "STOPPING=1")
sd.Notify(false, "READY=1")
for {
select {
case sig := <-sigs:
switch sig {
case syscall.SIGTERM:
logger.Notice("Received SIGTERM, shutting down")
return lsb.EXIT_SUCCESS
case syscall.SIGHUP:
sd.Notify(false, "RELOADING=1")
err := backend.Reload()
if err != nil {
logger.Notice("Could not reload backend: %s", err.Error())
return lsb.EXIT_NOTRUNNING
}
sd.Notify(false, "READY=1")
}
case conn := <-sock:
wg.Add(1)
go func() {
defer lsb.Recover()
defer wg.Done()
handler(conn, backend)
}()
}
}
}
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