Remove need to start executor as root

Now that we have a finger gateway, we no longer need to start the
executor as root so that the finger streamer on the executor can
bind to port 79 (default port for the finger streamer is changed
from 79 to 7900). Remove that requirement.

Change-Id: I6df685044c4ce81fd263043adba832609da100af

6 files changed, 13 insertions, 42 deletions

diff --git a/doc/source/admin/components.rst b/doc/source/admin/components.rst
index 3bec28afd..18bbfa3f4 100644
--- a/doc/source/admin/components.rst
+++ b/doc/source/admin/components.rst
@@ -408,7 +408,7 @@ The following sections of ``zuul.conf`` are used by the executor:
       Path to command socket file for the executor process.
 
    .. attr:: finger_port
-      :default: 79
+      :default: 7900
 
       Port to use for finger log streamer.
 
@@ -451,13 +451,6 @@ The following sections of ``zuul.conf`` are used by the executor:
 
       SSH private key file to be used when logging into worker nodes.
 
-   .. attr:: user
-      :default: zuul
-
-      User ID for the zuul-executor process. In normal operation as a
-      daemon, the executor should be started as the ``root`` user, but
-      it will drop privileges to this user during startup.
-
    .. _admin_sitewide_variables:
 
    .. attr:: variables
diff --git a/tests/unit/test_streaming.py b/tests/unit/test_streaming.py
index 59dd8b016..b999106c8 100644
--- a/tests/unit/test_streaming.py
+++ b/tests/unit/test_streaming.py
@@ -41,13 +41,13 @@ class TestLogStreamer(tests.base.BaseTestCase):
     def startStreamer(self, port, root=None):
         if not root:
             root = tempfile.gettempdir()
-        return zuul.lib.log_streamer.LogStreamer(None, self.host, port, root)
+        return zuul.lib.log_streamer.LogStreamer(self.host, port, root)
 
     def test_start_stop(self):
-        port = 7900
-        streamer = self.startStreamer(port)
+        streamer = self.startStreamer(0)
         self.addCleanup(streamer.stop)
 
+        port = streamer.server.socket.getsockname()[1]
         s = socket.create_connection((self.host, port))
         s.close()
 
@@ -77,8 +77,9 @@ class TestStreaming(tests.base.AnsibleZuulTestCase):
     def startStreamer(self, port, build_uuid, root=None):
         if not root:
             root = tempfile.gettempdir()
-        self.streamer = zuul.lib.log_streamer.LogStreamer(None, self.host,
+        self.streamer = zuul.lib.log_streamer.LogStreamer(self.host,
                                                           port, root)
+        port = self.streamer.server.socket.getsockname()[1]
         s = socket.create_connection((self.host, port))
         self.addCleanup(s.close)
 
@@ -129,10 +130,9 @@ class TestStreaming(tests.base.AnsibleZuulTestCase):
 
         # Create a thread to stream the log. We need this to be happening
         # before we create the flag file to tell the job to complete.
-        port = 7901
         streamer_thread = threading.Thread(
             target=self.startStreamer,
-            args=(port, build.uuid, self.executor_server.jobdir_root,)
+            args=(0, build.uuid, self.executor_server.jobdir_root,)
         )
         streamer_thread.start()
         self.addCleanup(self.stopStreamer)
@@ -209,7 +209,7 @@ class TestStreaming(tests.base.AnsibleZuulTestCase):
     def test_websocket_streaming(self):
         # Start the finger streamer daemon
         streamer = zuul.lib.log_streamer.LogStreamer(
-            None, self.host, 0, self.executor_server.jobdir_root)
+            self.host, 0, self.executor_server.jobdir_root)
         self.addCleanup(streamer.stop)
 
         # Need to set the streaming port before submitting the job
@@ -294,7 +294,7 @@ class TestStreaming(tests.base.AnsibleZuulTestCase):
     def test_finger_gateway(self):
         # Start the finger streamer daemon
         streamer = zuul.lib.log_streamer.LogStreamer(
-            None, self.host, 0, self.executor_server.jobdir_root)
+            self.host, 0, self.executor_server.jobdir_root)
         self.addCleanup(streamer.stop)
         finger_port = streamer.server.socket.getsockname()[1]
 
diff --git a/zuul/cmd/executor.py b/zuul/cmd/executor.py
index ade9715c2..ad7aaa837 100755
--- a/zuul/cmd/executor.py
+++ b/zuul/cmd/executor.py
@@ -14,10 +14,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import grp
 import logging
 import os
-import pwd
 import sys
 import signal
 import tempfile
@@ -64,7 +62,7 @@ class Executor(zuul.cmd.ZuulDaemonApp):
 
             self.log.info("Starting log streamer")
             streamer = zuul.lib.log_streamer.LogStreamer(
-                self.user, '::', self.finger_port, self.job_dir)
+                '::', self.finger_port, self.job_dir)
 
             # Keep running until the parent dies:
             pipe_read = os.fdopen(pipe_read)
@@ -76,22 +74,6 @@ class Executor(zuul.cmd.ZuulDaemonApp):
             os.close(pipe_read)
             self.log_streamer_pid = child_pid
 
-    def change_privs(self):
-        '''
-        Drop our privileges to the zuul user.
-        '''
-        if os.getuid() != 0:
-            return
-        pw = pwd.getpwnam(self.user)
-        # get a list of supplementary groups for the target user, and make sure
-        # we set them when dropping privileges.
-        groups = [g.gr_gid for g in grp.getgrall() if self.user in g.gr_mem]
-        os.setgroups(groups)
-        os.setgid(pw.pw_gid)
-        os.setuid(pw.pw_uid)
-        os.chdir(pw.pw_dir)
-        os.umask(0o022)
-
     def run(self):
         if self.args.command in zuul.executor.server.COMMANDS:
             self.send_command(self.args.command)
@@ -99,8 +81,6 @@ class Executor(zuul.cmd.ZuulDaemonApp):
 
         self.configure_connections(source_only=True)
 
-        self.user = get_default(self.config, 'executor', 'user', 'zuul')
-
         if self.config.has_option('executor', 'job_dir'):
             self.job_dir = os.path.expanduser(
                 self.config.get('executor', 'job_dir'))
@@ -120,7 +100,6 @@ class Executor(zuul.cmd.ZuulDaemonApp):
         )
 
         self.start_log_streamer()
-        self.change_privs()
 
         ExecutorServer = zuul.executor.server.ExecutorServer
         self.executor = ExecutorServer(self.config, self.connections,
diff --git a/zuul/executor/server.py b/zuul/executor/server.py
index 904d6e266..a8ab8c45e 100644
--- a/zuul/executor/server.py
+++ b/zuul/executor/server.py
@@ -44,7 +44,7 @@ from zuul.lib import commandsocket
 BUFFER_LINES_FOR_SYNTAX = 200
 COMMANDS = ['stop', 'pause', 'unpause', 'graceful', 'verbose',
             'unverbose', 'keep', 'nokeep']
-DEFAULT_FINGER_PORT = 79
+DEFAULT_FINGER_PORT = 7900
 BLACKLISTED_ANSIBLE_CONNECTION_TYPES = ['network_cli']
 
 
diff --git a/zuul/lib/log_streamer.py b/zuul/lib/log_streamer.py
index c778812a6..f96f44279 100644
--- a/zuul/lib/log_streamer.py
+++ b/zuul/lib/log_streamer.py
@@ -157,12 +157,11 @@ class LogStreamer(object):
     Class implementing log streaming over the finger daemon port.
     '''
 
-    def __init__(self, user, host, port, jobdir_root):
+    def __init__(self, host, port, jobdir_root):
         self.log = logging.getLogger('zuul.log_streamer')
         self.log.debug("LogStreamer starting on port %s", port)
         self.server = LogStreamerServer((host, port),
                                         RequestHandler,
-                                        user=user,
                                         jobdir_root=jobdir_root)
 
         # We start the actual serving within a thread so we can return to
diff --git a/zuul/lib/streamer_utils.py b/zuul/lib/streamer_utils.py
index 43bc28626..3d2d561b9 100644
--- a/zuul/lib/streamer_utils.py
+++ b/zuul/lib/streamer_utils.py
@@ -74,7 +74,7 @@ class CustomThreadingTCPServer(socketserver.ThreadingTCPServer):
     address_family = socket.AF_INET6
 
     def __init__(self, *args, **kwargs):
-        self.user = kwargs.pop('user')
+        self.user = kwargs.pop('user', None)
         self.pid_file = kwargs.pop('pid_file', None)
         socketserver.ThreadingTCPServer.__init__(self, *args, **kwargs)