diff options
| -rw-r--r-- | obfs4proxy/obfs4proxy.go | 72 | ||||
| -rw-r--r-- | obfs4proxy/termmon.go (renamed from obfs4proxy/parentMonitor.go) | 91 | ||||
| -rw-r--r-- | obfs4proxy/termmon_linux.go (renamed from obfs4proxy/parentMonitor_linux.go) | 4 |
3 files changed, 84 insertions, 83 deletions
diff --git a/obfs4proxy/obfs4proxy.go b/obfs4proxy/obfs4proxy.go index b27d75d..9b452ac 100644 --- a/obfs4proxy/obfs4proxy.go +++ b/obfs4proxy/obfs4proxy.go @@ -38,7 +38,6 @@ import ( "net" "net/url" "os" - "os/signal" "path" "sync" "syscall" @@ -60,7 +59,7 @@ const ( var enableLogging bool var unsafeLogging bool var stateDir string -var handlerChan chan int +var termMon *termMonitor // DialFn is a function pointer to a function that matches the net.Dialer.Dial // interface. @@ -176,10 +175,8 @@ func clientAcceptLoop(f base.ClientFactory, ln *pt.SocksListener, proxyURI *url. func clientHandler(f base.ClientFactory, conn *pt.SocksConn, proxyURI *url.URL) { defer conn.Close() - handlerChan <- 1 - defer func() { - handlerChan <- -1 - }() + termMon.onHandlerStart() + defer termMon.onHandlerFinish() name := f.Transport().Name() addrStr := elideAddr(conn.Req.Target) @@ -298,10 +295,8 @@ func serverAcceptLoop(f base.ServerFactory, ln net.Listener, info *pt.ServerInfo func serverHandler(f base.ServerFactory, conn net.Conn, info *pt.ServerInfo) { defer conn.Close() - handlerChan <- 1 - defer func() { - handlerChan <- -1 - }() + termMon.onHandlerStart() + defer termMon.onHandlerFinish() name := f.Transport().Name() addrStr := elideAddr(conn.RemoteAddr().String()) @@ -386,8 +381,8 @@ func getVersion() string { } func main() { - // Initialize parent process monitoring as early as possible. - pmonErr := initParentMonitor() + // Initialize the termination state monitor as soon as possible. + termMon = newTermMonitor() // Handle the command line arguments. _, execName := path.Split(os.Args[0]) @@ -405,10 +400,8 @@ func main() { log.Fatalf("[ERROR]: failed to set log level: %s", err) } - // Determine if this is a client or server, initialize logging, and finish - // the pt configuration. + // Determine if this is a client or server, initialize the common state. var ptListeners []net.Listener - handlerChan = make(chan int) launched := false isClient, err := ptIsClient() if err != nil { @@ -419,12 +412,10 @@ func main() { } if err = ptInitializeLogging(enableLogging); err != nil { log.Fatalf("[ERROR]: %s - failed to initialize logging", execName) - } else { - noticef("%s - launched", getVersion()) - if pmonErr != nil { - warnf("%s - failed to initialize parent monitor: %s", execName, pmonErr) - } } + noticef("%s - launched", getVersion()) + + // Do the managed pluggable transport protocol configuration. if isClient { infof("%s - initializing client transport listeners", execName) launched, ptListeners = clientSetup() @@ -444,39 +435,18 @@ func main() { }() // At this point, the pt config protocol is finished, and incoming - // connections will be processed. Per the pt spec, on sane platforms - // termination is signaled via SIGINT (or SIGTERM), so wait on tor to - // request a shutdown of some sort. - - sigChan := make(chan os.Signal, 1) - signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM) - - // Wait for the first SIGINT (close listeners). - var sig os.Signal - numHandlers := 0 - for sig == nil { - select { - case n := <-handlerChan: - numHandlers += n - case sig = <-sigChan: - if sig == syscall.SIGTERM { - // SIGTERM causes immediate termination. - return - } - } + // connections will be processed. Wait till the parent dies + // (immediate exit), a SIGTERM is received (immediate exit), + // or a SIGINT is received. + if sig := termMon.wait(false); sig == syscall.SIGTERM { + return } + + // Ok, it was the first SIGINT, close all listeners, and wait till, + // the parent dies, all the current connections are closed, or either + // a SIGINT/SIGTERM is received, and exit. for _, ln := range ptListeners { ln.Close() } - - // Wait for the 2nd SIGINT (or a SIGTERM), or for all current sessions to - // finish. - sig = nil - for sig == nil && numHandlers != 0 { - select { - case n := <-handlerChan: - numHandlers += n - case sig = <-sigChan: - } - } + termMon.wait(true) } diff --git a/obfs4proxy/parentMonitor.go b/obfs4proxy/termmon.go index e2f078d..eac7e20 100644 --- a/obfs4proxy/parentMonitor.go +++ b/obfs4proxy/termmon.go @@ -28,36 +28,47 @@ package main import ( - "fmt" "os" + "os/signal" "runtime" "syscall" "time" ) -var parentMonitorOSInit func() error +var termMonitorOSInit func(*termMonitor) error -func initParentMonitor() error { - // Until #15435 is implemented, there is no reliable way to see if - // the parent has died that is portable/platform independent/reliable. - // - // Do the next best thing and use various kludges and hacks: - // * Linux - Platform specific code that should always work. - // * Other U*IX - Somewhat generic code, that works unless the parent - // dies before the monitor is initialized. - // * Windows - Log an error, can't be bothered to figure out how - // to handle this there. - if parentMonitorOSInit != nil { - return parentMonitorOSInit() - } else if runtime.GOOS != "windows" { - ppid := os.Getppid() - go parentMonitorPpidChange(ppid) - return nil +type termMonitor struct { + sigChan chan os.Signal + handlerChan chan int + numHandlers int +} + +func (m *termMonitor) onHandlerStart() { + m.handlerChan <- 1 +} + +func (m *termMonitor) onHandlerFinish() { + m.handlerChan <- -1 +} + +func (m *termMonitor) wait(termOnNoHandlers bool) os.Signal { + // Block until a signal has been received, or (optionally) the + // number of pending handlers has hit 0. In the case of the + // latter, treat it as if a SIGTERM has been received. + for { + select { + case n := <-m.handlerChan: + m.numHandlers += n + case sig := <-m.sigChan: + return sig + } + if termOnNoHandlers && m.numHandlers == 0 { + return syscall.SIGTERM + } } - return fmt.Errorf("unsupported on: %s", runtime.GOOS) } -func parentMonitorPpidChange(ppid int) { +func (m *termMonitor) termOnPPIDChange(ppid int) { // Under most if not all U*IX systems, the parent PID will change // to that of init once the parent dies. There are several notable // exceptions (Slowlaris/Android), but the parent PID changes @@ -72,17 +83,37 @@ func parentMonitorPpidChange(ppid int) { time.Sleep(ppidPollInterval) } - // If possible SIGTERM ourself so that the normal shutdown code - // gets invoked. If any of that fails, exit anyway, we are a - // defunt process. + // Treat the parent PID changing as the same as having received + // a SIGTERM. noticef("Parent pid changed: %d (was %d)", os.Getppid(), ppid) - if p, err := os.FindProcess(os.Getpid()); err == nil { - if err := p.Signal(syscall.SIGTERM); err == nil { - return + m.sigChan <- syscall.SIGTERM +} + +func newTermMonitor() *termMonitor { + ppid := os.Getppid() + m := new(termMonitor) + m.sigChan = make(chan os.Signal) + m.handlerChan = make(chan int) + signal.Notify(m.sigChan, syscall.SIGINT, syscall.SIGTERM) + + // Until #15435 is implemented, there is no reliable way to see if + // the parent has died that is portable/platform independent/reliable. + // + // Do the next best thing and use various kludges and hacks: + // * Linux - Platform specific code that should always work. + // * Other U*IX - Somewhat generic code, that works unless the parent + // dies before the monitor is initialized. + // * Windows - Don't specifically monitor for parent termination. + if termMonitorOSInit != nil { + // Errors here are non-fatal, since it might still be possible + // to fall back to a generic implementation. + if err := termMonitorOSInit(m); err == nil { + return m } - warnf("Failed to SIGTERM ourself: %v", err) - } else { - warnf("Failed to find our own process: %v", err) } - os.Exit(-1) + if runtime.GOOS != "windows" { + go m.termOnPPIDChange(ppid) + } + + return m } diff --git a/obfs4proxy/parentMonitor_linux.go b/obfs4proxy/termmon_linux.go index 65fd307..9711cfc 100644 --- a/obfs4proxy/parentMonitor_linux.go +++ b/obfs4proxy/termmon_linux.go @@ -32,7 +32,7 @@ import ( "syscall" ) -func parentMonitorInitLinux() error { +func termMonitorInitLinux(m *termMonitor) error { // Use prctl() to have the kernel deliver a SIGTERM if the parent // process dies. This beats anything else that can be done before // #15435 is implemented. @@ -45,5 +45,5 @@ func parentMonitorInitLinux() error { } func init() { - parentMonitorOSInit = parentMonitorInitLinux + termMonitorOSInit = termMonitorInitLinux } |