A StartupItem is a MacPorts facility to run "daemons," a Unix term for programs that run continuously in the background, rather than under the direct control of a user; for example, mail servers, network listeners, etc. Ports that use StartupItem keywords create Mac OS X scripts for launchd, which is the Apple facility introduced with Mac OS X 10.4 to replace xinetd for starting and managing daemons. To support launchd, a program named daemondo is provided by MacPorts base that serves as an adapter between Mac OS X's launchd and daemons (“executable” StartupItems) or traditional Unix startup scripts that start daemons (“script” StartupItems).
There are three categories of StartupItem keywords. Those that trigger StartupItem creation and logging, those that specify attributes of “executable” StartupItems, and those that specify attributes of “script” StartupItems.
The variable startupitem_type in
${prefix}/etc/macports/macports.conf may be set to
none to globally override all StartupItem keywords found
in Portfiles; this prevents StartupItems from being created.
The keywords in this section may be used with either “executable” or “script” StartupItems (see below).
Trigger the creation of a StartupItem.
Default: no
Example:
startupitem.create yes
Sets the name for the StartupItem. Defaults to the name of the port, so this keyword is usually unnecessary.
Default: ${name}
Example:
startupitem.name dhcpd
Path to a logfile for logging events about the lifetime of the StartupItem. Depending on the type of StartupItem, and the manner in which it is started, standard output from the daemon may also be directed to the logfile.
Default: /dev/null
Example:
startupitem.logfile ${prefix}/var/log/mydaemon.logControl whether or not to log events to the log file. If logevents is set, events with timestamps are logged to the logfile.
Default: no
Example:
startupitem.logevents yes
Cause the daemon to be restarted when a change in network state is detected.
Default: no
Example:
startupitem.netchange yes
Daemons run continuously, so monitoring the health of daemon processes and restarting them if they die is an important StartupItems' feature. “Executable” StartupItems are preferred over “script” StartupItems because daemondo launches the daemon directly, rather than indirectly via a script, and therefore it automatically knows how to monitor a daemon process and restart it if it dies. Daemons used with “executable” StartupItems may be programs or scripts (shell, perl, python, etc.), but when a script is used the script itself must be the daemon, rather than merely what launches the daemon (for the latter,“script” StartupItems are to be used).
For a given port, the “executable” StartupItem keyword may not be used with any keywords in the “script” StartupItem category.
Specifies the name of the daemon to be run. It may have multiple arguments, but they must be appropriate for a call to exec; arbitrary shell code may not be used.
Some daemons "daemonize" by detaching themselves from the
controlling tty before sending themselves to the background, thus
making themselves a child of the original process. A daemon to be
started with startupitem.executable must not be
allowed to do this (daemondo will think the process has died and
start another instance); this can usually be turned off with a
switch so the daemon does not detach itself (runs as a foreground
process).
Default: none
Example:
startupitem.executable ${prefix}/sbin/vm-pop3d -d 10 -t 600Do not wrap values in quotes if passing arguments to the daemon; “executable” StartupItem elements must be tagged individually so the spaces between arguments serve as delimiters for “string” tags. For example, this startupitem key/value pair:
startupitem.executable ${prefix}/sbin/vm-pop3d -d 10 -t 600generates a .plist file with these tags:
<key>ProgramArguments</key>
<array>
<string>/opt/local/bin/daemondo</string>
<string>--label=vm-pop3d</string>
<string>--start-cmd</string>
<string>/opt/local/sbin/vm-pop3d</string>
<string>-d</string>
<string>10</string>
<string>-t</string>
<string>600</string>
<string>;</string>
</array>StartupItems of type “script” use daemondo to launch a daemon indirectly via a startup script. A typical snippet of a startup script that may be used with a “script” StartupItem is shown below. Notice that the script is not a daemon; rather the script indirectly launches the vm-pop3d daemon.
#!/bin/sh
case "$1" in
start)
echo -n "Starting vm-pop3d: "
/opt/local/sbin/vm-pop3d -d 10 -t 600
[... trimmed ...]But if a script itself is a daemon, use the
“executable” StartupItem type since that way it will be
launched directly and its health tracked automatically. When using
“script” StartupItems, the startupitem.pidfile
keyword must be used if you want daemondo to monitor a
daemon process and restart it if it dies.
For a given port, StartupItem keywords in category “script” may not be used with an “executable” StartupItem keyword.
Specify a shell script to start, stop, and restart the daemon.
In the absence of startupitem.restart, the daemon will
be restarted by taking the stop action, followed by the start
action.
Default: none
Examples:
startupitem.start "${prefix}/share/mysql/mysql.server start"
startupitem.stop "${prefix}/share/mysql/mysql.server stop"
startupitem.restart "${prefix}/share/mysql/mysql.server restart"Wrap the stop, start, and restart values in quotes so they will be placed in the wrapper tagged as a single element.
Shell code that will be executed prior to any of the options
startupitem.start, startupitem.stop and
startupitem.restart.
Default: none
Example:
startupitem.init BIN=${prefix}/sbin/bacula-fdThis keyword must be defined properly for daemondo to be able to monitor daemons launched via “script” StartupItems and restart them if they die. It specifies two things: a process id (PID) file handling method, and a pidfile name and path.
Default: none
${prefix}/var/run/${name}.pid
Default: [none] |
[${prefix}/var/run/${name}.pid]
Values [none auto manual clean]
[/path/to/pidfile]
Example:
startupitem.pidfile auto ${prefix}/var/run/${name}.pidfilePID file handling options:
none - daemondo will not create or track
a PID file, so it won't know when a daemon dies.
auto - The started process is expected to
create a PID file that contains the PID of the running daemon;
daemondo then reads the PID from the file and tracks the
process. The started process must delete the PID file if this is
necessary.
clean - The started process is expected
to create a PID file that contains the PID of the running
daemon; daemondo then reads the PID from the file and tracks the
process, and deletes the PID file if it detects the daemon has
died.
manual - This option should only be used
if an “executable” StartupItem could be used
(daemondo launches a daemon directly) and a
port author wants a PID file written for some special use. A PID
file is not needed to detect process death for daemons launched
directly by daemondo. As with executable StartupItems, daemondo
remembers the PID of the launched process and tracks it
automatically.
A port with a StartupItem places a link to a .plist file for the
port's daemon within /Library/LaunchDaemons/. A
.plist file is an XML file; MacPorts installs .plist files tagged as
“disabled” for the sake of security. You may enable a startup
script (tag the.plist file as “enabled”) and load it into
launchd with a single command as shown.
%%sudo launchctl load -w /Library/LaunchDaemons/org.macports.mysql5.plist
You may stop a running startup script, disable it (tag the.plist file as “disabled”), and unload it from launchd with a single command as shown.
%%sudo launchctl unload -w /Library/LaunchDaemons/org.macports.mysql5.plist
During port installation a MacPorts StartupItem creates a .plist
file in ${prefix}/etc/LaunchDaemons/, and places a
symbolic link to the .plist file within
/Library/LaunchDaemons/.
For example, the StartupItem for the mysql5 port is
org.macports.mysql5.plist, and it is linked as
shown.
%%ls -l /Library/LaunchDaemons
org.macports.mysql5.plist ->
/opt/local/etc/LaunchDaemons/org.macports.mysql5/org.macports.mysql5.plistFor “script” StartupItems, in addition to a .plist file, a wrapper is also created.
%%ls -l /opt/local/etc/LaunchDaemons/org.macports.mysql5/
-rwxr-xr-x 2 root wheel 475 Aug 2 14:16 mysql5.wrapper -rw-r--r-- 2 root wheel 975 Aug 2 14:16 org.macports.mysql5.plist
The wrapper manipulates the script as specified in the startupitem.start and startupitem.stop keywords. An example wrapper script snippet is shown below.
#!/bin/sh
# MacPorts generated daemondo support script
# Start
Start()
{
/opt/local/share/mysql5/mysql/mysql.server start
}
# Stop
Stop()
{
/opt/local/share/mysql5/mysql/mysql.server stop
}
[... trimmed ...]