Introduce a tiny init replacement for inside pid namespace

Reviewed-by: Zac Medico <zmedico@gentoo.org>
Signed-off-by: Michał Górny <mgorny@gentoo.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/bin/pid-ns-init b/bin/pid-ns-init
new file mode 100644
index 000000000..843257b70
--- /dev/null
+++ b/bin/pid-ns-init
@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+# Copyright 2018 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+import os
+import sys
+
+
+def main(argv):
+	if len(argv) < 2:
+		return 'Usage: {} <main-child-pid>'.format(argv[0])
+	main_child_pid = int(argv[1])
+
+	# wait for child processes
+	while True:
+		pid, status = os.wait()
+		if pid == main_child_pid:
+			if os.WIFEXITED(status):
+				return os.WEXITSTATUS(status)
+			elif os.WIFSIGNALED(status):
+				os.kill(os.getpid(), os.WTERMSIG(status))
+			# go to the unreachable place
+			break
+
+	# this should never be reached
+	return 127
+
+
+if __name__ == '__main__':
+	sys.exit(main(sys.argv))