From: Gregory P. Smith <greg@mad-scientist.com>
Date: Tue, 14 Dec 2010 15:16:24 +0000 (+0000)
Subject: Merged revisions 87233 via svnmerge from
X-Git-Tag: v3.2.1b1~347^2~174
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b740e76af01bdd34e53d3c03b812e452f5d9a4e8;p=thirdparty%2FPython%2Fcpython.git

Merged revisions 87233 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k

........
  r87233 | gregory.p.smith | 2010-12-14 06:38:00 -0800 (Tue, 14 Dec 2010) | 4 lines

  Issue #1731717: Fixed the problem where subprocess.wait() could cause an
  OSError exception when The OS had been told to ignore SIGCLD in our process
  or otherwise not wait for exiting child processes.
........
---

diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 0dd55e0f74e7..5684d523952c 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -1149,7 +1149,11 @@ class Popen(object):
                 os.close(errpipe_read)
 
             if data:
-                _eintr_retry_call(os.waitpid, self.pid, 0)
+                try:
+                    _eintr_retry_call(os.waitpid, self.pid, 0)
+                except OSError as e:
+                    if e.errno != errno.ECHILD:
+                        raise
                 child_exception = pickle.loads(data)
                 for fd in (p2cwrite, c2pread, errread):
                     if fd is not None:
@@ -1195,7 +1199,15 @@ class Popen(object):
             """Wait for child process to terminate.  Returns returncode
             attribute."""
             if self.returncode is None:
-                pid, sts = _eintr_retry_call(os.waitpid, self.pid, 0)
+                try:
+                    pid, sts = _eintr_retry_call(os.waitpid, self.pid, 0)
+                except OSError as e:
+                    if e.errno != errno.ECHILD:
+                        raise
+                    # This happens if SIGCLD is set to be ignored or waiting
+                    # for child processes has otherwise been disabled for our
+                    # process.  This child is dead, we can't get the status.
+                    sts = 0
                 self._handle_exitstatus(sts)
             return self.returncode
 
diff --git a/Lib/test/subprocessdata/sigchild_ignore.py b/Lib/test/subprocessdata/sigchild_ignore.py
new file mode 100644
index 000000000000..1d03303e447e
--- /dev/null
+++ b/Lib/test/subprocessdata/sigchild_ignore.py
@@ -0,0 +1,6 @@
+import signal, subprocess, sys
+# On Linux this causes os.waitpid to fail with OSError as the OS has already
+# reaped our child process.  The wait() passing the OSError on to the caller
+# and causing us to exit with an error is what we are testing against.
+signal.signal(signal.SIGCLD, signal.SIG_IGN)
+subprocess.Popen([sys.executable, '-c', 'print("albatross")']).wait()
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 2379b3e5fe4c..adf00a50a078 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -793,6 +793,17 @@ class ProcessTestCase(BaseTestCase):
                 stdout = stdout.rstrip(b'\n\r')
                 self.assertEqual(stdout, value_repr)
 
+        def test_wait_when_sigchild_ignored(self):
+            # NOTE: sigchild_ignore.py may not be an effective test on all OSes.
+            sigchild_ignore = support.findfile("sigchild_ignore.py",
+                                               subdir="subprocessdata")
+            p = subprocess.Popen([sys.executable, sigchild_ignore],
+                                 stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+            stdout, stderr = p.communicate()
+            self.assertEqual(0, p.returncode, "sigchild_ignore.py exited"
+                             " non-zero with this error:\n%s" % stderr)
+
+
     #
     # Windows tests
     #
diff --git a/Misc/NEWS b/Misc/NEWS
index 0f9a78539847..058b02a6971a 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -35,6 +35,10 @@ Library
 
 - Issue #10464: netrc now correctly handles lines with embedded '#' characters.
 
+- Issue #1731717: Fixed the problem where subprocess.wait() could cause an
+  OSError exception when The OS had been told to ignore SIGCLD in our process
+  or otherwise not wait for exiting child processes.
+
 Extensions
 ----------