From 00ca7552317bb69ce8eb84582d658d5e52997394 Mon Sep 17 00:00:00 2001
From: John Hawkinson <jhawk@mit.edu>
Date: Fri, 21 Oct 2016 20:44:49 -0400
Subject: [PATCH] [get_exe_version] Do version probes with <&-
When doing version probes for ffmpeg, do the
equivalent of calling it as:
ffmpeg -version <&-
Where <&- is shell syntax for closing stdin before calling the
program. This is roughly equivalent to </dev/null without actually
opening /dev/null.
This prevents ffmpeg -version from hanging when run in the background.
Fixes #955.
The reason is that ffmpeg tries to manipulate stdin to set up terminal
characteristic, and that causes the kernel to suspend the parent
process (youtube-dl).
Note that closing stdin is achieved by calling subprocess.Popen() with
stdin set to subprocess.PIPE and without passing any input to
Popen.communicate(). This is somewhat subtle.
---
youtube_dl/utils.py | 1 +
1 file changed, 1 insertion(+)
diff --git a/youtube_dl/utils.py b/youtube_dl/utils.py
index 28941673f..a89ff6908 100644
--- a/youtube_dl/utils.py
+++ b/youtube_dl/utils.py
@@ -1820,6 +1820,7 @@ def get_exe_version(exe, args=['--version'],
try:
out, _ = subprocess.Popen(
[encodeArgument(exe)] + args,
+ stdin=subprocess.PIPE,
stdout=subprocess.PIPE, stderr=subprocess.STDOUT).communicate()
except OSError:
return False