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macOS Creating a Launch Deamon for Portsentry

A

ACagliano

macrumors newbie
Original poster
May 10, 2012
11
0
I have a program called portsentry that can be run under OS X using the following command line commands:

/opt/local/libexec/portsentry.sh -tcp
/opt/local/libexec/portsentry.sh -udp

So, instead of doing this every time I log in, I decided to create a script. However, when I launch the deamon, then do "ps aux | grep portsentry", it shows nothing running. What am I doing wrong in this script? I'm assuming I'm making a mistake with the plist file.

Code: 
#!/bin/bash
# Mac OS X portsentry installation script
#
#
echo
echo This script will enable portsentry
echo and create a plist file to start up
echo the portsentry daemon at startup.
echo 
echo Press enter to continue...


# Set permissions
chown root:admin /opt/local/libexec/portsentry.sh
chmod 544 /opt/local/libexec/portsentry.sh

# Set up the plist file finally
echo "Setting up plist file at Library/LaunchDaemons/com.apple.portsentry.plist"

if ! touch /Library/LaunchDaemons/com.apple.portsentry.plist ; then
    echo Cannot touch the Library/LaunchDaemons/com.apple.portsentry.plist file.
    echo Exiting due to the previous error.
    exit
fi

echo -e "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" > /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "<!DOCTYPE plist PUBLIC \"-//Apple//DTD PLIST 1.0 //EN\" \"http://www.apple.com/DTDs/PropertyList-1.0.dtd\">" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "<plist version=\"1.0\">" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "<dict>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    <key>Label</key>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    <string>com.apple.portsentry</string>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    <key>ProgramArguments</key>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    <array>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "        <string>/opt/local/libexec/portsentry.sh -tcp</string>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "        <string>/opt/local/libexec/portsentry.sh -udp</string>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    </array>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    <key>RunAtLoad</key>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    <true/>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "</dict>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "</plist>" >> /Library/LaunchDaemons/com.apple.portsentry.plist

chown root:admin /Library/LaunchDaemons/com.apple.portsentry.plist

echo "Complete."
echo
echo "Starting portsentry..."
launchctl load /Library/LaunchDaemons/com.apple.portsentry.plist
echo "Portsentry now active and running:"
ps aux | grep portsentry

echo
echo Done.
 
ACagliano said:
I have a program called portsentry that can be run under OS X using the following command line commands:

/opt/local/libexec/portsentry.sh -tcp
/opt/local/libexec/portsentry.sh -udp

So, instead of doing this every time I log in, I decided to create a script. However, when I launch the deamon, then do "ps aux | grep portsentry", it shows nothing running. What am I doing wrong in this script? I'm assuming I'm making a mistake with the plist file.
Click to expand...

As a test, try the modification below and see if portsentry runs:

Code: 
#!/bin/bash
# Mac OS X portsentry installation script
#
#
echo
echo This script will enable portsentry
echo and create a plist file to start up
echo the portsentry daemon at startup.
echo 
echo Press enter to continue...


# Set permissions
chown root:admin /opt/local/libexec/portsentry.sh
chmod 544 /opt/local/libexec/portsentry.sh

# Set up the plist file finally
echo "Setting up plist file at Library/LaunchDaemons/com.apple.portsentry.plist"

if ! touch /Library/LaunchDaemons/com.apple.portsentry.plist ; then
    echo Cannot touch the Library/LaunchDaemons/com.apple.portsentry.plist file.
    echo Exiting due to the previous error.
    exit
fi

echo -e "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" > /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "<!DOCTYPE plist PUBLIC \"-//Apple//DTD PLIST 1.0 //EN\" \"http://www.apple.com/DTDs/PropertyList-1.0.dtd\">" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "<plist version=\"1.0\">" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "<dict>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    <key>Label</key>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    <string>com.apple.portsentry</string>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    <key>ProgramArguments</key>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    <array>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "        <string>/opt/local/libexec/portsentry.sh</string>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "        <string>-tcp</string>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    </array>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    <key>RunAtLoad</key>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "    <true/>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "</dict>" >> /Library/LaunchDaemons/com.apple.portsentry.plist
echo -e "</plist>" >> /Library/LaunchDaemons/com.apple.portsentry.plist

chown root:admin /Library/LaunchDaemons/com.apple.portsentry.plist

echo "Complete."
echo
echo "Starting portsentry..."
launchctl load /Library/LaunchDaemons/com.apple.portsentry.plist
echo "Portsentry now active and running:"
ps aux | grep portsentry

echo
echo Done.

See https://developer.apple.com/library.../Reference/ManPages/man5/launchd.plist.5.html for more.
 
1/31/13 10:50:39.805 AM com.apple.launchd.peruser.502[474]: (com.apple.portsentry[1789]) Job failed to exec(3). Setting up event to tell us when to try again: 2: No such file or directory

So, it runs, but it seems that the file or directory doesn't exist. Yet it does...
 
If you haven't read TN2083 "Daemons and Agents", you should:
http://developer.apple.com/library/mac/#technotes/tn2083/_index.html


Where did portsentry.sh come from?

What testing of the script as a daemon have you done? Does it work when put in background by the shell? Does it work under 'nohup'? What are its needs for user-ids, permissions, ownership, working directory, login session?

Have you tested it as a per-user LaunchAgent instead of as a system-wide LaunchDaemon?

Have you made any other plists for any other agents or daemons? Even an agent as simple as waking up once a minute and writing a file.


This message:
1/31/13 10:50:39.805 AM com.apple.launchd.peruser.502[474]: (com.apple.portsentry[1789]) Job failed to exec(3). Setting up event to tell us when to try again: 2: No such file or directory
​
seems to be saying that it's launching a peruser job. However, the install script does this:
Code: 
chown root:admin /opt/local/libexec/portsentry.sh
chmod 544 /opt/local/libexec/portsentry.sh
The result of the chown and chmod is that the script is only executable for the owner (root), not for any admin-group or other. This seems inconsistent with a peruser job.
 
Ah Portsentry. Takes me back to them Linux days. So what happens when you run those commands in Terminal? Does ps aux | grep portsentry shows they're running? Also Portsentry is not standard on OS X. Did you compile it from source or did you install it through MacPorts or Homebrew or a precompiled binary for your system? Seems like you've been trying for some time to get this going as per this link : http://www.cemetech.net/forum/viewtopic.php?t=8474&postdays=0&postorder=asc&start=0. You ask on that link to start the following Terminal commands on startup :

Code: 
sudo /opt/local/libexec/portsentry -tcp 
sudo /opt/local/libexec/portsentry -udp

yet your first post here states this :

Code: 
/opt/local/libexec/portsentry.sh -tcp 
/opt/local/libexec/portsentry.sh -udp

Like chown33 said the result of the chown and chmod is that the script is only executable for the owner (root).

Edit : I installed Portsentry via Macports and lo and behold it was installed in the /opt/local/libexec/ directory. As you can see in the screenshot it's a Unix Executable File and doesn't end in .sh.

The contents of com.apple.portsentry.plist file :

Code: 
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0 //EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>com.apple.portsentry</string>
    <key>ProgramArguments</key>
    <array>
        <string>/opt/local/libexec/portsentry</string>
        <string>-tcp</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
</dict>
</plist>
 

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Last edited:
Yeah, I have been trying for a while to get it working. I installed it via MacPorts.

The strange thing is that doing both:

/opt/local/libexec/portsentry AND /opt/local/libexec/portsentry.sh with the correct arguments works.

I'll try out what you did.

Edit: So, your example works fine and PortSentry starts up in TCP mode. Now, I would also like it started in UDP mode too. On the command line, you have to actually run the command twice to start it in both modes. Must I create another plist file?

@kryten2: It works perfectly fine on OS X, but it doesn't support the stealth scan mode or advanced mode.
 
Last edited:
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