April 2008 - launchd-dev - lists.macosforge.org

Re: [launchd-dev] How to on demand launch for configurable port number?
by Mike Fischer 02 Apr '08

02 Apr '08

Am 01.04.2008 um 13:34 schrieb Quinn <eskimo1(a)apple.com>: > At 22:15 +0100 29/3/08, Mike Fischer wrote: >> Currently I'd immagine that I need to 'launchctl stop' the service, >> modify the associated launchd.plist to reflect the currently >> configured port and then 'launchctl start' the service. > > You would probably have to "unload" and "load", rather than "stop" > and "start". Stop/start just affects the running process, so launchd > will not reconsult the relevant plist file. Right, Thanks! (I'm still learning my way around the launchd world and its terminology.) So "unload" makes launchd completely forget about a service while "load" does the reverse? >> Unless of course there is a better way that doesn't involve changing >> the launchd.plist? > > I can't think of one. OK. >> Not sure if this is relevant but the daemon does not use Bonjour at >> the moment to advertise its service. That could be added though (and >> might be a good idea for other reasons). > > If you used Bonjour, you could just bind to a ephemeral port > ("SockServiceName" == "0") and find the service, which includes the > port, using Bonjour. No need for fixed ports at all. Sounds like a good idea. I'll have to look into this. Of course the clients would then need to rely on Bonjour as well which might be difficult to achieve as the Mac OS X port of the client software is only a small part of their customer base. I'm not sure I can convince them to use Bonjour on the other platforms. There may also be issues with Bonjour normally being Link-Local in situations where the end- users have more complex networks with multiple subnets. Using Dynamic DNS Update might be difficult to implement in the field. But all this is OT on this list I guess... Thanks for your time and insight! Mike -- Mike Fischer Softwareentwicklung, EDV-Beratung Schulung, Vertrieb Web: <http://homepage.mac.com/mike_fischer/index.html> Note: I read this list in digest mode! Send me a private copy for faster responses.

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Re: [launchd-dev] OnDemand USB Software
by Mike Fischer 01 Apr '08

01 Apr '08

Am 01.04.2008 um 13:34 schrieb Quinn <eskimo1(a)apple.com>: > At 22:02 +0100 29/3/08, Mike Fischer wrote: >> BTW: The launchd.plist(5) man page contains references to a >> launch(3) man page (10.5.2, Xcode 3.0 as well as 10.4.11, Xcode >> 2.4.1). Unfortunatly the launch(3) man page does not seem to exist. >> Filed as <rdar://5830171>. I saw /usr/include/launch.h and the >> SampleD sample code but these don't really explain what is going on >> and how to properly check-in with launchd. Any hints on where to get >> more information? > > Thanks for all those bug reports. We appreciate 'em. Sure, glad to help. FWIW it came back as duplicate of <rdar:// 3886256> which seems rather old judging by the number. > IMHO the best example of how to use launchd with a UNIX domain > socket is: > > <http://developer.apple.com/samplecode/BetterAuthorizationSample/ > index.html> I never would have thought to look there ;-) Interesting sample though. Thanks for the tip. >> If I understand this correctly I would not be using the socket for >> actual communication, just for triggering the launch of the >> "server", i.e. the real (on demand) daemon? > > That's the idea, yes. > >> Would I need to add the SockFamily or SockProtocol keys and if so >> what would be the correct values for a UNIX domain socket? >> Anything else I'd need to add? > > o SockFamily == Unix > > o SockPathMode is typically 438 (0666, rw-rw-rw-) -- This may not > strictly be necessary in your case because the code that's connecting > is privileged. > > o SockNodeName == ??? -- It's generally best to put this in a > privileged location (/var/run/) rather than in /tmp. OK. BetterAuthorizationSample does a good job of demonstrating this. >> In the real daemon I'd do a socket(2), bind(2), accept(2) (the >> listen(2) is already done by launchd I gather)? Or do I need this at >> all? > > In a launchd daemon you don't need to do the socket, or the bind, or > the listen. You just get a file descriptor for the socket from > launchd (using LAUNCH_KEY_CHECKIN) and accept connections from that. Ah, I see now. Makes sense in retrospect. Again thanks for your help! Mike -- Mike Fischer Softwareentwicklung, EDV-Beratung Schulung, Vertrieb Web: <http://homepage.mac.com/mike_fischer/index.html> Note: I read this list in digest mode! Send me a private copy for faster responses.

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MachServices
by Pradip Patel 01 Apr '08

01 Apr '08

Hi I am using LaunchDaemons to execute daemon on Mac OS 10.5 I am using IOKit in my daemons But while it executing daemons it give error in IOServiceOpen API at the time of boot So which services i have to add with MachServices property key Thanks p2 -- _____________________________________________________________________ Disclaimer: This e-mail message and all attachments transmitted with it are intended solely for the use of the addressee and may contain legally privileged and confidential information. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, copying, or other use of this message or its attachments is strictly prohibited. If you have received this message in error, please notify the sender immediately by replying to this message and please delete it from your computer. Any views expressed in this message are those of the individual sender unless otherwise stated.Company has taken enough precautions to prevent the spread of viruses. However the company accepts no liability for any damage caused by any virus transmitted by this email. _____________________________________________________________________

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Fw: [launchd-dev] MachServices
by Pradip Patel 01 Apr '08

01 Apr '08

Re: [launchd-dev] MachServicessame thing work on 10.4 ----- Original Message ----- From: Pradip Patel To: launchd-dev(a)lists.macosforge.org ; Quinn Sent: Tuesday, April 01, 2008 5:12 PM Subject: Re: [launchd-dev] MachServices Yes it works in post boot, can you please tell me the name of IOkit service ? is it com.apple.iokit ? p2 ----- Original Message ----- From: Quinn To: launchd-dev(a)lists.macosforge.org Sent: Tuesday, April 01, 2008 5:04 PM Subject: Re: [launchd-dev] MachServices At 13:48 +0530 1/4/08, Pradip Patel wrote: I am using LaunchDaemons to execute daemon on Mac OS 10.5 I am using IOKit in my daemons But while it executing daemons it give error in IOServiceOpen API at the time of boot So which services i have to add with MachServices property key I think you're a bit in the weeds here. Are you trying to connect to a service or vend a service? The MachServices property is only relevant if you're trying to vend a Mach service. You don't need to put anything special in your launchd property list file to just connect to a service. Does this stuff work if you load your daemon post boot? My best guess, given the info above, is that you're trying to connect to an I/O Kit service early in the boot process, and the service hasn't got around to being registered yet. S+E -- Quinn "The Eskimo!" <http://www.apple.com/developer/> Apple Developer Relations, Developer Technical Support, Core OS/Hardware - This message has been scanned for viruses, spam and dangerous content and is believed to be clean. ------------------------------------------------------------------------------ _______________________________________________ launchd-dev mailing list launchd-dev(a)lists.macosforge.org http://lists.macosforge.org/mailman/listinfo/launchd-dev -- _____________________________________________________________________ Disclaimer: This e-mail message and all attachments transmitted with it are intended solely for the use of the addressee and may contain legally privileged and confidential information. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, copying, or other use of this message or its attachments is strictly prohibited. If you have received this message in error, please notify the sender immediately by replying to this message and please delete it from your computer. Any views expressed in this message are those of the individual sender unless otherwise stated.Company has taken enough precautions to prevent the spread of viruses. However the company accepts no liability for any damage caused by any virus transmitted by this email. _____________________________________________________________________

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Re: [launchd-dev] OnDemand USB Software
by Mike Fischer 01 Apr '08

01 Apr '08

Hi Quinn, sorry for the delay, somehow I missed your answer (probably because the mailing list digest only arrived two days ago, 9 days after you sent the answer ;-). Am 27.03.2008 um 16:12 schrieb Quinn <eskimo1(a)apple.com>: > At 23:23 +0100 17/3/08, Mike Fischer wrote: >> So far, looking at tn2083 and the man pages, I don't see any way to >> have a depency on USB or IOKit in general. Am I missing something >> here? > > No, you're not missing something. This is a much-requested feature > that we're tracking as <rdar://problem/4551362>. OK. If we go ahead with this project I'll probably file a (duplicate) bug to raise the priority. >> If there is no direct support would it make sense to have a very >> small, lightweight daemon always running that registers for IOKit >> IOServiceAddMatchingNotification notifications and creates a >> semaphore file that can be used to trigger the launch of the real >> daemon for example? > > That's a fine way to do it. I probably wouldn't use a semaphore > file, because it persists in the file system. However, there are > numerous other options available to you. If I was doing this, I'd > probably have your main daemon register a UNIX domain socket and have > your lightweight daemon connect to that socket to trigger a launch. OK. The semaphore file was just the first trigger I could think of that would work with launchd. The UNIX domain socket is probably a better idea. If I understand this correctly I would not be using the socket for actual communication, just for triggering the launch of the "server", i.e. the real (on demand) daemon? So I'd include something like this in the real daemon's launchd.plist: <key>Sockets</key> <dict> <key>Listeners</key> <dict> <key>SockNodeName</key> <string>/tmp/MYSOCKETNAME</string> </dict> </dict> Would I need to add the SockFamily or SockProtocol keys and if so what would be the correct values for a UNIX domain socket? Anything else I'd need to add? In the real daemon I'd do a socket(2), bind(2), accept(2) (the listen (2) is already done by launchd I gather)? Or do I need this at all? And in the USB-Watcher daemon I'd do a socket(2), connect(2), which would trigger the launch of the real daemon right? BTW: The launchd.plist(5) man page contains references to a launch(3) man page (10.5.2, Xcode 3.0 as well as 10.4.11, Xcode 2.4.1). Unfortunatly the launch(3) man page does not seem to exist. Filed as <rdar://5830171>. I saw /usr/include/launch.h and the SampleD sample code but these don't really explain what is going on and how to properly check-in with launchd. Any hints on where to get more information? >> BTW: This would be mainly for Leopard, although Tiger would be >> interesting too. > > This approach would work just fine on 10.4.x (x >= 6 if you use UNIX > domain sockets). Good to know. Now I need to discuss these options with my customer and see if we can do this without completely changing their existing cross platform code. Thanks! Your answer is very much appreciated. Mike -- Mike Fischer Softwareentwicklung, EDV-Beratung Schulung, Vertrieb Web: <http://homepage.mac.com/mike_fischer/index.html> Note: I read this list in digest mode! Send me a private copy for faster responses.

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How to on demand launch for configurable port number?
by Mike Fischer 01 Apr '08

01 Apr '08

Hi! Let's say I have a daemon that listens on a TCP port. The exact port number can be configured, i.e. it is not fixed. It might even change when the user changes the configuration, albeit not very often. Actually this daemon is a HTTP server that serves status information about a service. Thus it will not be used most of the time. Always running the server would be a waste of resources IMHO and I want avoid that by making it an on-demand service. Is it possible to make launchd launch the daemon on demand when a connection request comes in? If so how would I specify this in the launchd.plist file, taking into account the varying TCP port number? Currently I'd immagine that I need to 'launchctl stop' the service, modify the associated launchd.plist to reflect the currently configured port and then 'launchctl start' the service. Unless of course there is a better way that doesn't involve changing the launchd.plist? Not sure if this is relevant but the daemon does not use Bonjour at the moment to advertise its service. That could be added though (and might be a good idea for other reasons). I tried to find similar services, for example the Apache Web Server. But while it uses configurable port numbers it does not launch on demand unfortunatly. So I can't use it as an example of how to do this. Thanks! Mike -- Mike Fischer Softwareentwicklung, EDV-Beratung Schulung, Vertrieb Web: <http://homepage.mac.com/mike_fischer/index.html> Note: I read this list in digest mode! Send me a private copy for faster responses.

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