December 2007 - launchd-dev - lists.macosforge.org

UserName ignored on per-user LaunchAgents
by Jeremy Reichman 17 Dec '07

17 Dec '07

This may be something of a "duh" but I'm curious if it is intentional and immutable that per-user LaunchAgents, such as those a sys admin might want to stuff into /Library/LaunchAgents, ignore the "UserName" key. In launchd.plist's man page: "UserName <string> This optional key specifies the user to run the job as. The default is the user who submitted the job to launchd." When that key is specified in a LaunchAgent, even one in /Library/LaunchAgents, I've found that the key is ignored, a message to that effect is written to the system.log, and the job runs as the user that is logging in. Why do I want to specify it? Well, launchd tasks have certain advantages over LoginHook (and LogoutHook). If I could replace LoginHook scripts -- which, let's face it, are limited in that they have to be called by a single script parent script (similar to `/usr/sbin/periodic`) -- with launchd tasks, I'd much prefer to do so. For one thing, there's no modification of the loginwindow plist -- and the use of individual launchd jobs would make it much easier to run multiple tasks. The most obvious way to accomplish that is with a LaunchAgent, but Login|LogoutHook run as root. Hence the problem. If your LoginHook-type tasks need root access for whatever reason, then the obvious launchd way to set that up is with the UserName key in your job plist. But it doesn't work. I can see the wisdom of ignoring the key, but if a sys admin has placed a job in /Library/LaunchAgents, and that directory is installed with the system using restrictive permissions, and the job is owned by root, there would seem to be several adequate safeguards in place to make malicious use difficult. (Application Launch Restrictions are already depending on the filesystem location and permissions, at least in managed environments, so it would seem that launchd could do so as well.) I would be supportive of other reasonable safeguards besides these, too, including script signing and more. Besides asking whether ignoring the UserName key is meant to be this way and could be changed in the future if enhancement requests were filed, is there another way to replace the hooks with launchd? Thanks! -- Jeremy

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run gui LaunchAgent from launchd
by bobkells＠steelcape.com 16 Dec '07

16 Dec '07

Not having any luck running a LaunchAgent containing a gui from launchd. Is this simply not possible?

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Re: [launchd-dev] Run job when network configuration changes
by Christopher Hunt 15 Dec '07

15 Dec '07

Le 5 déc. 07 à 16:04, Jeremy Reichman a écrit : > I would be just as happy if there were a file that was > consistently and > reliably modified during network changes, so that the WatchPaths > key could > be used. I'm not aware of such a file and past discussions about > this on the > MacEnterprise list haven't turned one up (to my recollection), but > that > doesn't mean it doesn't exist. > I've not really been following this thread but, if I were wanting to do this, I think I'd write a little bit of Cocoa to detect network configuration changes and write a file to a location that a launchd job watches. I following a similar strategy for some other launchd based actions. Works nicely. Cheers, -C

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Run job when network configuration changes
by Louis Granboulan 13 Dec '07

13 Dec '07

Dear all, I would like to support Jeremy Reichman's request, because I apparently have similar needs. I have used the Kicker.xml technique to make automatic backups of my laptop. However, this laptop connects to various networks, and should backup only when connected to the ones where enough bandwidth is available. Moreover, one of such networks uses a 802.1x authentication, and I can backup only when authenticated. In that case, I go from a wired- non-authenticated connection to a wired-authenticated connection, and I need to launch the backup script after authentication. Thanks, Louis

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launch cocoa-app (with gui) from launchd
by Bob Kells 12 Dec '07

12 Dec '07

Problem may be resolved. I'm looking at my code that issues the runModal call. My NSAlert object is created within a loop that depends on the number of alerts to display. I was retain/releasing this object within the loop. I noticed that NSAlert is autoreleased, so I removed the retain/release statements, and now I get my alert panels. Again, this worked outside of launchd with the retain/release. But now it appears to be working when launched from launchd. My next step is to skip the script, and call it directly from launchd. I'll let you know the outcome tomorrow...bob

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launch cocoa-app (with gui) from launchd
by bob kells 12 Dec '07

12 Dec '07

I have been unsuccessful so far attempting to launch an xcode cocoa app from launchd. I have tried loading 2 different versions of a plist that reference either the executable, or the .app bundle. Neither works. I noticed a prior listing explaining that the actual exe must be referenced, not the .app bundle. ps shows that the process actually gets created both ways. However, nothing appears. I am able to launch the app successfully from a script file and the cmd-line. But when the script file (which launches the app) is run via launchd, again nothing happens. I am using WatchPaths, and the Program key has been set to either the executable, or the .app bundle. Any suggestions out there? thanks...bob -- View this message in context: http://www.nabble.com/launch-cocoa-app-%28with-gui%29-from-launchd-tp142659… Sent from the Launchd mailing list archive at Nabble.com.

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Configurion a Cocoa app as a user agent
by James Bucanek 10 Dec '07

10 Dec '07

Greetings, I have a Login Item that I'd like to replace with a ~/Library/LaunchAgent. It's a LSUIElement=YES Cocoa application. What should the executable path be? If I set it to the bundle folder, is launchd smart enough to figure out that its an application? Or do I need to set it to .../MyApp.app/Contents/MacOS/MyApp? I ask because I've been warned by the Cocoa engineers to avoid starting applications that way. -- James Bucanek

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Thanks for the WatchPath behavior change
by Jeremy Reichman 05 Dec '07

05 Dec '07

I've also noticed, in the theme of being thankful for changes in Leopard, that the behavior for the WatchPath key is different. I believe that change is for the better. In Leopard, both creating and deleting the watched path results in any job waiting for its modification to fire. This is great -- in Tiger, my experience was that the path always had to exist and that made WatchPath more limited and less useful. One question though: since removing the path also runs the job, is there a way to avoid that specific behavior? To only have the job run if the path is created or is modified in place (without deletion)? I know that that case is probably one where the QueueDirectory key should be used instead, but I figured I'd ask. Again, thanks! -- Jeremy

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Sincere thanks about wake from sleep
by Jeremy Reichman 05 Dec '07

05 Dec '07

I have tested launchd jobs that were scheduled to run during sleep subsequently execute when a system is woken up. I'm happy that missed jobs do now run -- and they run immediately upon wake in Leopard. In Tiger, if the jobs ran, it was hours later. They were greatly offset from the time of system wake. This made the use of scheduled overnight jobs less useful from a systems administration perspective, and Leopard definitely improves upon that experience. Thanks! -- Jeremy

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Cross-job coalescing
by Jeremy Reichman 05 Dec '07

05 Dec '07

I haven't found a way to do this after looking over the docs (but not the new TechNote) ... I am wondering if there is a way to have two or more launchd tasks that call the same script coalesce into the same event during events like wake from sleep. For example, what if the same script is called by both a nightly job, and a weekly job? Are the various instances of the jobs that would have run automatically then coalesced into one instance if their scheduled execution is missed? Or, if not, is there a way to have some other cross-job identifier that is shared by multiple launchd jobs so that the same target script is not run more than once? TIA. -- Jeremy

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