Close inherited PIPE before doing work

Gmake in Darwin has file descriptor leak.
In a full build, ota_from_target_files will inherits
more than 2000 open PIPEs from gmake and fails in a call to select.select().
This change fixes the build by closing the PIPEs before doing real work.

Change-Id: Ie7035d7add0b1da3afb6bf9c2009d40f8c7d29b3

tools/releasetools/common.py

@@ -18,6 +18,7 @@ import getopt
 import getpass
 import imp
 import os
+import platform
 import re
 import shutil
 import subprocess
@@ -63,6 +64,22 @@ def Run(args, **kwargs):
   return subprocess.Popen(args, **kwargs)
 
 
+def CloseInheritedPipes():
+  """ Gmake in MAC OS has file descriptor (PIPE) leak. We close those fds
+  before doing other work."""
+  if platform.system() != "Darwin":
+    return
+  for d in range(3, 1025):
+    try:
+      stat = os.fstat(d)
+      if stat is not None:
+        pipebit = stat[0] & 0x1000
+        if pipebit != 0:
+          os.close(d)
+    except OSError:
+      pass
+
+
 def LoadInfoDict(zip):
   """Read and parse the META/misc_info.txt key/value pairs from the
   input target files and return a dict."""

tools/releasetools/img_from_target_files

@@ -201,6 +201,7 @@ def main(argv):
 
 if __name__ == '__main__':
   try:
+    common.CloseInheritedPipes()
     main(sys.argv[1:])
   except common.ExternalError, e:
     print

tools/releasetools/ota_from_target_files

@@ -807,6 +807,7 @@ def main(argv):
 
 if __name__ == '__main__':
   try:
+    common.CloseInheritedPipes()
     main(sys.argv[1:])
   except common.ExternalError, e:
     print