[tor-commits] [meek/master] Have terminateprocess-buffer wait on either of stdin closing or child exiting.

[dcf at torproject.org]

commit 29797a33ecee1c6fc4882fc2b6beabcd64f554ce
Author: David Fifield <david at bamsoftware.com>
Date:   Fri Apr 19 00:01:43 2019 -0600

    Have terminateprocess-buffer wait on either of stdin closing or child exiting.
    
    On Windows, I observed once that if meek-client.exe can't be found,
    tor.exe and its child process terminateprocess-buffer.exe continued
    running. I suspect terminateprocess-buffer was hung up in io.Copy--the
    child process stdin pipe was closed, but as it has nothing to copy, it
    couldn't detect the fact. Now have it do the stdin copy in a separate
    goroutine, and also close the child stdin pipe explicitly.
---
 terminateprocess-buffer/terminateprocess-buffer.go | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/terminateprocess-buffer/terminateprocess-buffer.go b/terminateprocess-buffer/terminateprocess-buffer.go
index 85df446..afedc77 100644
--- a/terminateprocess-buffer/terminateprocess-buffer.go
+++ b/terminateprocess-buffer/terminateprocess-buffer.go
@@ -42,7 +42,16 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	io.Copy(stdin, os.Stdin)
+	go func() {
+		_, err := io.Copy(stdin, os.Stdin)
+		if err != nil {
+			log.Fatalf("copying stdin: %v", err)
+		}
+		err = stdin.Close()
+		if err != nil {
+			log.Fatalf("closing stdin: %v", err)
+		}
+	}()
 	err = cmd.Wait()
 	if err != nil {
 		log.Fatal(err)