From 0260032ce37a960f7c619a1bbc891434ff84c927 Mon Sep 17 00:00:00 2001
From: Iustin Pop <iustin@google.com>
Date: Tue, 5 Oct 2010 13:05:50 +0200
Subject: [PATCH] Abstract some daemon functionality
This patch abstracts the chdir/umask/setsid functionality, which is
identical in the code functions, just that Daemonize did the chdir/umask
in the second child; with this change it does it in the first, as
StartDaemon.
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>
---
lib/utils.py | 30 +++++++++++++++++++++---------
1 file changed, 21 insertions(+), 9 deletions(-)
diff --git a/lib/utils.py b/lib/utils.py
index 8f7c031d1..3a6d67a72 100644
--- a/lib/utils.py
+++ b/lib/utils.py
@@ -237,6 +237,21 @@ def RunCmd(cmd, env=None, output=None, cwd="/", reset_env=False,
return RunResult(exitcode, signal_, out, err, strcmd)
+def SetupDaemonEnv(cwd="/", umask=077):
+ """Setup a daemon's environment.
+
+ This should be called between the first and second fork, due to
+ setsid usage.
+
+ @param cwd: the directory to which to chdir
+ @param umask: the umask to setup
+
+ """
+ os.chdir(cwd)
+ os.umask(umask)
+ os.setsid()
+
+
def StartDaemon(cmd, env=None, cwd="/", output=None, output_fd=None,
pidfile=None):
"""Start a daemon process after forking twice.
@@ -344,9 +359,7 @@ def _StartDaemonChild(errpipe_read, errpipe_write,
_CloseFDNoErr(pidpipe_read)
# First child process
- os.chdir("/")
- os.umask(077)
- os.setsid()
+ SetupDaemonEnv()
# And fork for the second time
pid = os.fork()
@@ -354,7 +367,8 @@ def _StartDaemonChild(errpipe_read, errpipe_write,
# Exit first child process
os._exit(0) # pylint: disable-msg=W0212
- # Make sure pipe is closed on execv* (and thereby notifies original process)
+ # Make sure pipe is closed on execv* (and thereby notifies
+ # original process)
SetCloseOnExecFlag(errpipe_write, True)
# List of file descriptors to be left open
@@ -2132,18 +2146,16 @@ def Daemonize(logfile):
"""
# pylint: disable-msg=W0212
# yes, we really want os._exit
- UMASK = 077
- WORKDIR = "/"
# this might fail
pid = os.fork()
if (pid == 0): # The first child.
- os.setsid()
+ SetupDaemonEnv()
+
# this might fail
pid = os.fork() # Fork a second child.
if (pid == 0): # The second child.
- os.chdir(WORKDIR)
- os.umask(UMASK)
+ pass # nothing special to do in the child
else:
# exit() or _exit()? See below.
os._exit(0) # Exit parent (the first child) of the second child.
--
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