commit 125b0ca14312085def735bc8c239097972a166c5 Author: David Fifield <david@bamsoftware.com> Date: Sun Sep 25 22:23:57 2016 -0700 Ignore SIGPIPE in meek-client-torbrowser. See https://bugs.torproject.org/20030 for discussion. Since Go 1.6, writes to fd 1 or 2 when they are closed causes the program to terminate with a SIGPIPE. Because the default log location is stderr (fd 2), we would get a SIGPIPE when logging once the parent process had died and closed its stderr. This prevented meek-client-torbrowser from cleaning up its subprocesses. --- meek-client-torbrowser/meek-client-torbrowser.go | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/meek-client-torbrowser/meek-client-torbrowser.go b/meek-client-torbrowser/meek-client-torbrowser.go index 450f9fa..4f3531d 100644 --- a/meek-client-torbrowser/meek-client-torbrowser.go +++ b/meek-client-torbrowser/meek-client-torbrowser.go @@ -289,6 +289,17 @@ func main() { log.SetOutput(f) } + // By default, writes to file descriptor 1 and 2 when the descriptor has + // been closed will terminate the program with a SIGPIPE signal. This is + // a problem because the default log destination is stderr (file + // descriptor 2). When the parent process (tor) terminates and closes + // its stderr, any attempt to log will cause us to die, before we can do + // our own cleanup. Therefore ignore SIGPIPE, causing writes to a closed + // stderr to return syscall.EPIPE rather than terminate. + // https://golang.org/pkg/os/signal/#hdr-SIGPIPE + // https://bugs.torproject.org/20030#comment:6 + signal.Notify(make(chan os.Signal, 1), syscall.SIGPIPE) + sigChan := make(chan os.Signal, 1) signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)