Add pylint to depot_tools.

third_party/logilab/common/daemon.py

+# copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
+#
+# This file is part of logilab-common.
+#
+# logilab-common is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation, either version 2.1 of the License, or (at your option) any
+# later version.
+#
+# logilab-common is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License along
+# with logilab-common.  If not, see <http://www.gnu.org/licenses/>.
+"""A daemonize function (for Unices)"""
+
+__docformat__ = "restructuredtext en"
+
+import os
+import errno
+import signal
+import sys
+import time
+import warnings
+
+def setugid(user):
+    """Change process user and group ID
+
+    Argument is a numeric user id or a user name"""
+    try:
+        from pwd import getpwuid
+        passwd = getpwuid(int(user))
+    except ValueError:
+        from pwd import getpwnam
+        passwd = getpwnam(user)
+
+    if hasattr(os, 'initgroups'): # python >= 2.7
+        os.initgroups(passwd.pw_name, passwd.pw_gid)
+    else:
+        import ctypes
+        if ctypes.CDLL(None).initgroups(passwd.pw_name, passwd.pw_gid) < 0:
+            err = ctypes.c_int.in_dll(ctypes.pythonapi,"errno").value
+            raise OSError(err, os.strerror(err), 'initgroups')
+    os.setgid(passwd.pw_gid)
+    os.setuid(passwd.pw_uid)
+    os.putenv('HOME', passwd.pw_dir)
+
+
+def daemonize(pidfile=None, uid=None, umask=077):
+    """daemonize a Unix process. Set paranoid umask by default.
+
+    Return 1 in the original process, 2 in the first fork, and None for the
+    second fork (eg daemon process).
+    """
+    # http://www.faqs.org/faqs/unix-faq/programmer/faq/
+    #
+    # fork so the parent can exit
+    if os.fork():   # launch child and...
+        return 1
+    # disconnect from tty and create a new session
+    os.setsid()
+    # fork again so the parent, (the session group leader), can exit.
+    # as a non-session group leader, we can never regain a controlling
+    # terminal.
+    if os.fork():   # launch child again.
+        return 2
+    # move to the root to avoit mount pb
+    os.chdir('/')
+    # set umask if specified
+    if umask is not None:
+        os.umask(umask)
+    # redirect standard descriptors
+    null = os.open('/dev/null', os.O_RDWR)
+    for i in range(3):
+        try:
+            os.dup2(null, i)
+        except OSError, e:
+            if e.errno != errno.EBADF:
+                raise
+    os.close(null)
+    # filter warnings
+    warnings.filterwarnings('ignore')
+    # write pid in a file
+    if pidfile:
+        # ensure the directory where the pid-file should be set exists (for
+        # instance /var/run/cubicweb may be deleted on computer restart)
+        piddir = os.path.dirname(pidfile)
+        if not os.path.exists(piddir):
+            os.makedirs(piddir)
+        f = file(pidfile, 'w')
+        f.write(str(os.getpid()))
+        f.close()
+        os.chmod(pidfile, 0644)
+    # change process uid
+    if uid:
+        setugid(uid)
+    return None