Add a way to print output from commands

Instead pof always capturing the output, make it possible to let
it go to the standard output pipes.
Use this in ipactl to let init scripts show their output.

Fixes: https://fedorahosted.org/freeipa/ticket/765

ipapython/ipautil.py

@@ -92,7 +92,8 @@ def write_tmp_file(txt):
 
     return fd
 
-def run(args, stdin=None, raiseonerr=True, nolog=(), env=None):
+def run(args, stdin=None, raiseonerr=True,
+        nolog=(), env=None, capture_output=True):
     """
     Execute a command and return stdin, stdout and the process return code.
 
@@ -116,14 +117,23 @@ def run(args, stdin=None, raiseonerr=True, nolog=(), env=None):
 
     If an value isn't found in the list it is silently ignored.
     """
+    p_in = None
+    p_out = None
+    p_err = None
+
     if env is None:
         env={"PATH": "/bin:/sbin:/usr/kerberos/bin:/usr/kerberos/sbin:/usr/bin:/usr/sbin"}
     if stdin:
-        p = subprocess.Popen(args, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True, env=env)
-        stdout,stderr = p.communicate(stdin)
-    else:
-        p = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True, env=env)
-        stdout,stderr = p.communicate()
+        p_in = subprocess.PIPE
+    if capture_output:
+        p_out = subprocess.PIPE
+        p_err = subprocess.PIPE
+    elif len(nolog):
+        raise RuntimeError("Can't use nolog if output is not captured")
+
+    p = subprocess.Popen(args, stdin=p_in, stdout=p_out, stderr=p_err,
+                         close_fds=True, env=env)
+    stdout,stderr = p.communicate(stdin)
 
     # The command and its output may include passwords that we don't want
     # to log. Run through the nolog items.
@@ -137,8 +147,9 @@ def run(args, stdin=None, raiseonerr=True, nolog=(), env=None):
         stdout = stdout.replace(quoted, 'XXXXXXXX')
         stderr = stderr.replace(quoted, 'XXXXXXXX')
     logging.info('args=%s' % args)
-    logging.info('stdout=%s' % stdout)
-    logging.info('stderr=%s' % stderr)
+    if capture_output:
+        logging.info('stdout=%s' % stdout)
+        logging.info('stderr=%s' % stderr)
 
     if p.returncode != 0 and raiseonerr:
         raise CalledProcessError(p.returncode, args)