image-swab: Convert to attach strace to the process to obtain the required swabber data

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/swabber-strace-attach

@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+import os
+import sys
+
+# Detach from the controlling terminal and parent process by forking twice to daemonize ourselves,
+# then run the command passed as argv[1]. Send log data to argv[2].
+
+pid = os.fork()
+if (pid == 0):
+    os.setsid()
+    pid = os.fork()
+    if (pid != 0):
+        os._exit(0)
+else:
+    sys.exit()
+
+
+si = file(os.devnull, 'r')
+so = file(sys.argv[2], 'w')
+se = so
+
+# Replace those fds with our own
+os.dup2(si.fileno(), sys.stdin.fileno())
+os.dup2(so.fileno(), sys.stdout.fileno())
+os.dup2(se.fileno(), sys.stderr.fileno())
+
+ret = os.system(sys.argv[1])
+
+os._exit(ret)
+