[STABLE] [PATCH] base.bbclass: Replace os.system with subprocess call.

[Cory Maccarrone <darkstar6262@gmail.com>]

(This patch is being submitted on behalf of Khem Raj.  I am not the original
author, nor do I claim any part of this work.)
--------------

Often gzip is reporting broken pipe errors with do_unpack of
tar.gz files.

If you use the commands described above to extract a tar.gz file, gzip
sometimes emits a Broken pipe error message. This can safely be ignored
if tar extracted all files without any other error message.

We do not let python install its SIGPIPE handler and use subprocess call
to invoke the command.

This is based on the following python bug report.
http://bugs.python.org/issue1652

Signed-off-by: Khem Raj <raj.khem@gmail.com>
---
 classes/base.bbclass |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/classes/base.bbclass b/classes/base.bbclass
index e622aee..69d1979 100644
--- a/classes/base.bbclass
+++ b/classes/base.bbclass
@@ -716,9 +716,14 @@ base_do_buildall() {
 	:
 }
 
+def subprocess_setup():
+	import signal, subprocess
+	# Python installs a SIGPIPE handler by default. This is usually not what
+	# non-Python subprocesses expect.
+	signal.signal(signal.SIGPIPE, signal.SIG_DFL)
 
 def oe_unpack_file(file, data, url = None):
-	import bb, os
+	import bb, os, signal, subprocess
 	if not url:
 		url = "file://%s" % file
 	dots = file.split(".")
@@ -787,7 +792,7 @@ def oe_unpack_file(file, data, url = None):
 
 	cmd = "PATH=\"%s\" %s" % (bb.data.getVar('PATH', data, 1), cmd)
 	bb.note("Unpacking %s to %s/" % (base_path_out(file, data), base_path_out(os.getcwd(), data)))
-	ret = os.system(cmd)
+	ret = subprocess.call(cmd, preexec_fn=subprocess_setup, shell=True)
 
 	os.chdir(save_cwd)
 
-- 
1.6.3.3