// +build !windows // Copyright 2019 The Gitea Authors. All rights reserved. // Use of this source code is governed by a MIT-style // license that can be found in the LICENSE file. // This code is heavily inspired by the archived gofacebook/gracenet/net.go handler package graceful import ( "fmt" "net" "os" "strconv" "strings" "sync" "code.gitea.io/gitea/modules/log" ) const ( listenFDs = "LISTEN_FDS" startFD = 3 ) // In order to keep the working directory the same as when we started we record // it at startup. var originalWD, _ = os.Getwd() var ( once = sync.Once{} mutex = sync.Mutex{} providedListeners = []net.Listener{} activeListeners = []net.Listener{} ) func getProvidedFDs() (savedErr error) { // Only inherit the provided FDS once but we will save the error so that repeated calls to this function will return the same error once.Do(func() { mutex.Lock() defer mutex.Unlock() numFDs := os.Getenv(listenFDs) if numFDs == "" { return } n, err := strconv.Atoi(numFDs) if err != nil { savedErr = fmt.Errorf("%s is not a number: %s. Err: %v", listenFDs, numFDs, err) return } for i := startFD; i < n+startFD; i++ { file := os.NewFile(uintptr(i), fmt.Sprintf("listener_FD%d", i)) l, err := net.FileListener(file) if err == nil { // Close the inherited file if it's a listener if err = file.Close(); err != nil { savedErr = fmt.Errorf("error closing provided socket fd %d: %s", i, err) return } providedListeners = append(providedListeners, l) continue } // If needed we can handle packetconns here. savedErr = fmt.Errorf("Error getting provided socket fd %d: %v", i, err) return } }) return savedErr } // CloseProvidedListeners closes all unused provided listeners. func CloseProvidedListeners() error { mutex.Lock() defer mutex.Unlock() var returnableError error for _, l := range providedListeners { err := l.Close() if err != nil { log.Error("Error in closing unused provided listener: %v", err) if returnableError != nil { returnableError = fmt.Errorf("%v & %v", returnableError, err) } else { returnableError = err } } } providedListeners = []net.Listener{} return returnableError } // GetListener obtains a listener for the local network address. The network must be // a stream-oriented network: "tcp", "tcp4", "tcp6", "unix" or "unixpacket". It // returns an provided net.Listener for the matching network and address, or // creates a new one using net.Listen. func GetListener(network, address string) (net.Listener, error) { // Add a deferral to say that we've tried to grab a listener defer InformCleanup() switch network { case "tcp", "tcp4", "tcp6": tcpAddr, err := net.ResolveTCPAddr(network, address) if err != nil { return nil, err } return GetListenerTCP(network, tcpAddr) case "unix", "unixpacket": unixAddr, err := net.ResolveUnixAddr(network, address) if err != nil { return nil, err } return GetListenerUnix(network, unixAddr) default: return nil, net.UnknownNetworkError(network) } } // GetListenerTCP announces on the local network address. The network must be: // "tcp", "tcp4" or "tcp6". It returns a provided net.Listener for the // matching network and address, or creates a new one using net.ListenTCP. func GetListenerTCP(network string, address *net.TCPAddr) (*net.TCPListener, error) { if err := getProvidedFDs(); err != nil { return nil, err } mutex.Lock() defer mutex.Unlock() // look for a provided listener for i, l := range providedListeners { if isSameAddr(l.Addr(), address) { providedListeners = append(providedListeners[:i], providedListeners[i+1:]...) activeListeners = append(activeListeners, l) return l.(*net.TCPListener), nil } } // no provided listener for this address -> make a fresh listener l, err := net.ListenTCP(network, address) if err != nil { return nil, err } activeListeners = append(activeListeners, l) return l, nil } // GetListenerUnix announces on the local network address. The network must be: // "unix" or "unixpacket". It returns a provided net.Listener for the // matching network and address, or creates a new one using net.ListenUnix. func GetListenerUnix(network string, address *net.UnixAddr) (*net.UnixListener, error) { if err := getProvidedFDs(); err != nil { return nil, err } mutex.Lock() defer mutex.Unlock() // look for a provided listener for i, l := range providedListeners { if isSameAddr(l.Addr(), address) { providedListeners = append(providedListeners[:i], providedListeners[i+1:]...) activeListeners = append(activeListeners, l) return l.(*net.UnixListener), nil } } // make a fresh listener l, err := net.ListenUnix(network, address) if err != nil { return nil, err } activeListeners = append(activeListeners, l) return l, nil } func isSameAddr(a1, a2 net.Addr) bool { // If the addresses are not on the same network fail. if a1.Network() != a2.Network() { return false } // If the two addresses have the same string representation they're equal a1s := a1.String() a2s := a2.String() if a1s == a2s { return true } // This allows for ipv6 vs ipv4 local addresses to compare as equal. This // scenario is common when listening on localhost. const ipv6prefix = "[::]" a1s = strings.TrimPrefix(a1s, ipv6prefix) a2s = strings.TrimPrefix(a2s, ipv6prefix) const ipv4prefix = "0.0.0.0" a1s = strings.TrimPrefix(a1s, ipv4prefix) a2s = strings.TrimPrefix(a2s, ipv4prefix) return a1s == a2s } func getActiveListeners() []net.Listener { mutex.Lock() defer mutex.Unlock() listeners := make([]net.Listener, len(activeListeners)) copy(listeners, activeListeners) return listeners }