June 2006 - Darwin-dev - lists.apple.com

Re: Question on using launchd from a C program
by Paul Nelson 09 Jun '06

09 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Thread-index: AcaLx4CpvwP9nPe6EdqTeQAWy4i6sA== Thread-topic: Question on using launchd from a C program User-agent: Microsoft-Entourage/11.2.3.060209 It's probably a real sin to suggest this, but since you are waiting for lepoard anyway.... Add this, and the associated observeNotices to your background app: [[NSDistributedNotificationCenter defaultCenter] addObserver:self selector:@selector(observeNotices:) name:nil object:nil suspensionBehavior:NSNotificationSuspensionBehaviorDeliverImmediately ]; In observeNotices, print out the NSNotification name and object values. You will get everything, since the above addObserver call didn't specify. Look at what gets printed out. Here are some event names you might be interested in: com.apple.userWillLogOut - the object will be a string containing the user id com.apple.sessionDidMoveOffConsole - for fast user switching com.apple.sessionDidMoveOnConsole - for fast user switching Once you figure out what notifications you like, replace the addObserver with specific calls to register for specific notifications. I've used these calls from a "faceless background app". They work fine. If you don't like objective C, then figure out how to make similar calls from CoreFoundation. Of course, these will just get you by until Apple fully documents how to do this kind of thing in Leapord.... Paul Nelson Thursby Software Systems, Inc. > From: Mike Kobb <mjkobb(a)alum.mit.edu> > Date: Thu, 8 Jun 2006 19:09:38 -0700 > To: <darwin-dev(a)lists.apple.com> > Subject: Re: Question on using launchd from a C program > > Thanks for that! I did consider the login/logout hooks, and I think > they could well work, but to install them you need administrator > privileges, and ideally I would not like to have to have the user > have to authenticate to set up the login behavior. > > I think what I'm going to do instead is write a very simple faceless > app that will be set as a login item. It will launch my server when > it launches at login (if the user chose login-time launch), and at > logout it'll find the server and tell it to quit. Should be very > straightforward, and has the advantage (compared to launchd) of > working on older OSes as well. > > Appreciate the suggestion. > --Mike > > On Jun 8, 2006, at 6:38 PM, Andre LaBranche wrote: > >> >> On Jun 8, 2006, at 6:04 PM, Mike Kobb wrote: >> >>> Unfortunately, I need this to work, well, today if possible. ;-) >>> >>> I'm sorry if I mis-typed. It's login and logout that I care >>> about. Not boot or shutdown (except insofar as shutdown implies >>> logout). I want them to be able to choose to launch it at login, >>> or do it manually. Then, if it's running when they log out >>> (whichever of those two methods they chose), I want it to quit. >>> ... >> >> Perhaps a loginhook / logouthook would work for the interim? >> >> http://developer.apple.com/documentation/MacOSX/Conceptual/ >> BPSystemStartup/Articles/CustomLogin.html >> >> Cheers, >> -Andre >> >>> >>> On Jun 8, 2006, at 4:37 PM, Dave Zarzycki wrote: >>> >>>> Will you be attending WWDC? >>>> >>>> Can you wait for Leopard? >>>> >>>> Why the asymmetric requirement of launching at boot, but exiting >>>> at logout (as opposed to at boot/shutdown or login/logout)? >>>> >>>> davez >>>> >>>> On Jun 8, 2006, at 3:55 PM, Mike Kobb wrote: >>>> >>>>> Greetings, >>>>> >>>>> I'm working on a MacOS preference pane that is used to configure >>>>> the options of a faceless background process (a music server). >>>>> >>>>> This process is a BSD process for historical reasons, but will >>>>> run under the privileges of a particular user, and not as root. >>>>> >>>>> I want to have a pop-up in the prefs pane that allows the user >>>>> to choose to manually launch the server (by clicking a "Start" >>>>> button in the pane, or to have the server launch at startup. >>>>> Either way, I want to be sure that the server quits when they >>>>> log out. >>>>> >>>>> It seems like launchd is likely to be what I want, but there are >>>>> a few things I could use some help with. >>>>> >>>>> I have figured out how to create the appropriate plist to make >>>>> the server launch at login and quit at shutdown, and that seems >>>>> to work fine. >>>>> >>>>> So, I have two questions: >>>>> >>>>> 1) Is it possible to set up launchd to not launch the process at >>>>> login, but to shut it down at logout? >>>>> >>>>> 2) I want this all to be controlled by my preference pane. >>>>> Obviously, it's no trouble to get it to write out the required >>>>> plist file, but the part I'm not sure about is how to do the >>>>> equivalent of a "launchctl load" or "launchctl unload" >>>>> operation. I could exec this, I guess, but I prefer to use a >>>>> proper C API rather than the exec mechanism whenever I can. I >>>>> couldn't make heads or tails out of launch.h, I'm afraid. >>>>> >>>>> Thanks in advance, >>>>> --Mike > > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/darwin-dev/nelson%40thursby.com > > This email sent to nelson(a)thursby.com > _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: Very early load and usage of higher level APIs
by Shaun Wexler 09 Jun '06

09 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On Jun 9, 2006, at 1:28 AM, Kevin Van Vechten wrote: Possible workaround: put it into /etc/mach_init.d/zzzz.my.daemon.plist -- Shaun Wexler MacFOH http://www.macfoh.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… * launchtl might be somewhat non-deterministic in how plists are loaded. If at times your plist is loaded before the coreservicesd or securityd plist, then the lookups for those services will fail, which causes the API to return an error rather than block. Maybe reverse the order of args in rc? I believe it loads them alphabetically, and in order of argv[]. From /etc/rc: # Load [ideally on demand] daemons if [ "${SafeBoot}" = "-x" ]; then launchctl load /System/Library/LaunchDaemons /etc/mach_init.d else launchctl load /Library/LaunchDaemons /System/Library/ LaunchDaemons /etc/mach_init.d SystemStarter ${VerboseFlag} fi "I refuse to answer that question on the grounds that I don't know the answer." -- Douglas Adams This email sent to site_archiver(a)lists.apple.com

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Re: Very early load and usage of higher level APIs
by Shaun Wexler 09 Jun '06

09 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On Jun 8, 2006, at 10:56 PM, Ryan McGann wrote: Carbon is not daemon-safe, so you're SOL there. Tech Note 2083: <http://developer.apple.com/technotes/tn2005/tn2083.html> #include <mach/mach_time.h> #include <servers/bootstrap.h> char *servicename[] = { "com.apple.CoreServices.coreservicesd", "com.apple.windowserver.active" }; HTH~ -- Shaun Wexler MacFOH http://www.macfoh.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Now that the launchd discussion has died down, I guess it's time to kick up the ashes with an honest question. We are using launchd in Tiger to startup our daemon. It is currently not load-on-demand, so it gets launched very early. It's usually process ID 18-25. We seem to be experiencing some problems in Tiger related to how early we get started. In particular, the following APIs seem to rely on daemons to perform their dirty work, but those daemons are not ready when we use them: - The Carbon Alias Manager which is used to determine the location of some files saved in the preferences accessed by our daemon. Sometimes the Alias Manager fails to resolve the aliases, even though they point to files that have not changed. We are using FSResolveAliasNoUI to resolve the alias in our daemon. - The cdsa wrapper libCdsa, which fails sometimes in cdsaCspAttach Both of these issues are reliably unreliable, in that they happen every 1 out of 5 reboots or so. It took quite a bit of time to narrow things down, but by adding a LOT of syslog statements, we found that these two APIs randomly fail. Looking at the syslog and process list in ps, I see that coreservicesd is launched very soon after our daemon, so I am guessing that the Carbon File Manager uses coreservicesd. I am *guessing* that the Security framework uses securityd. Since launchd has no dependancy list, how can I tell launchd that we need these daemons launched *and ready* when our daemon loads? Of course this won't work for services that are on-demand/inactive, but how about something like this (untested, written in Mail): bootstrap_status_t serviceactive; mach_timebase_info_data_t info; (void)mach_timebase_info(&info); uint64_t poll_interval = 1000000000ULL * info.denom / info.numer; // 1 second uint32_t i = 0; do { while (bootstrap_status(bootstrap_port, servicename[i], &serviceactive) == BOOTSTRAP_UNKNOWN_SERVICE && ! serviceactive) { mach_wait_until(poll_interval + mach_absolute_time()); } } while (++i < sizeof(servicename) / sizeof(servicename[0])); This email sent to site_archiver(a)lists.apple.com

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Re: the Virtual Memory
by Graham J Lee 09 Jun '06

09 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com User-agent: Thunderbird 1.5.0.4 (Macintosh/20060530) total used free shared buffers cached Swap: 2000084 0 2000084 Cheers, Graham. [*]which would probably explain why I didn't do that before. :-) -- Graham Lee UNIX Systems Manager, Oxford Physics Practical Course http://iamleeg.blogspot.com/ _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… On 9/6/06 01:17, Jordan K. Hubbard wrote: You might look at the source code for top(1) - it grubs through a lot of this information. Thanks Jordan, I actually did use top (and vm_stat) to work out how to get the vm statistics and report on the real memory usage. At the time I couldn't see what I wanted for swap usage, but I'll look again now that I've read more (the virtual memory chapter in "Mach 3 Kernel Principles" by Loepere/OSF is helping quite a lot). To me, it looks like there's no way to produce output equivalent to the analogous program on Linux[*], which (abridged) produces this: because their VMM uses static files/partitions of fixed size and then just works until they're full (or you swapon(2) another), whereas the Darwin VMM is dynamically growing (and, if the moon is in the third house and a two-headed calf has been born, plus some nonsense about low water marks and filesizes, shrinking) its usage on the filesystem, so in principle there's no "total" swap availability, modulo hard drive space... ...which leads me to answer a question from my original post; is there a way to get xnu to start swapping on a new partition? The answer seems to be to use /sbin/dynamic_pager (from system_cmds), however there's still no way to report on what external paging files are currently in use nor to disable one (so if you do go load-balancing your swapspace across multiple disks, you'd better remember not to forcibly unmount any of them). That would potentially be useful <sfx:reads some more, cracks open Xcode>. This email sent to site_archiver(a)lists.apple.com

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Re: Very early load and usage of higher level APIs
by Kevin Van Vechten 09 Jun '06

09 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com - Kevin On Jun 8, 2006, at 10:56 PM, Ryan McGann wrote: Thanks, Ryan _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… I'm responding off the top of my head, so I could be wrong, but I believe your analysis is correct and the Carbon File Manager does rely on coreservicesd to some extent, and the Security.framework relies on securityd as well. In the "launchd model" you should not have to specify a dependency. (The fact that a daemon is consulted is really and implementation detail of the API you're calling.) These APIs should be making blocking calls to the daemons in question--and launchd should launch the daemons when the calls are made. The fact that this isn't happening is a bug in the system, not in your code. I can imagine a few possible explanations (but this is pure speculation): * launchtl might be somewhat non-deterministic in how plists are loaded. If at times your plist is loaded before the coreservicesd or securityd plist, then the lookups for those services will fail, which causes the API to return an error rather than block. * coreservicesd or securityd might not be properly servicing requests before they're fully initialized. They should not service requests until they've initialized themselves, but perhaps they're dequeuing a message they can't handle yet and returning an error. It would help tremendously if you could file a bug <http:// developer.apple.com/bugreporter/>. Distilling it into a small test case, or at least describing the specific API calls you're making, will help us diagnose the problem. Now that the launchd discussion has died down, I guess it's time to kick up the ashes with an honest question. We are using launchd in Tiger to startup our daemon. It is currently not load-on-demand, so it gets launched very early. It's usually process ID 18-25. We seem to be experiencing some problems in Tiger related to how early we get started. In particular, the following APIs seem to rely on daemons to perform their dirty work, but those daemons are not ready when we use them: - The Carbon Alias Manager which is used to determine the location of some files saved in the preferences accessed by our daemon. Sometimes the Alias Manager fails to resolve the aliases, even though they point to files that have not changed. We are using FSResolveAliasNoUI to resolve the alias in our daemon. - The cdsa wrapper libCdsa, which fails sometimes in cdsaCspAttach Both of these issues are reliably unreliable, in that they happen every 1 out of 5 reboots or so. It took quite a bit of time to narrow things down, but by adding a LOT of syslog statements, we found that these two APIs randomly fail. Looking at the syslog and process list in ps, I see that coreservicesd is launched very soon after our daemon, so I am guessing that the Carbon File Manager uses coreservicesd. I am *guessing* that the Security framework uses securityd. Since launchd has no dependancy list, how can I tell launchd that we need these daemons launched *and ready* when our daemon loads? For now, I've hacked around these issues by doing a very kluddy for loop: for ( int i = 0; i < 5; i++ ) { // Call Alia Manager needlessly // Call cdsaCspAttach uneedlessly } But this seems just as error prone, since as machines get faster we might need to change the loop to 10 iterations, etc. Any suggestions? rmcgann(a)mac.com This email sent to site_archiver(a)lists.apple.com

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Very early load and usage of higher level APIs
by Ryan McGann 09 Jun '06

09 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Thanks, Ryan rmcgann(a)mac.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Now that the launchd discussion has died down, I guess it's time to kick up the ashes with an honest question. We are using launchd in Tiger to startup our daemon. It is currently not load-on-demand, so it gets launched very early. It's usually process ID 18-25. We seem to be experiencing some problems in Tiger related to how early we get started. In particular, the following APIs seem to rely on daemons to perform their dirty work, but those daemons are not ready when we use them: - The Carbon Alias Manager which is used to determine the location of some files saved in the preferences accessed by our daemon. Sometimes the Alias Manager fails to resolve the aliases, even though they point to files that have not changed. We are using FSResolveAliasNoUI to resolve the alias in our daemon. - The cdsa wrapper libCdsa, which fails sometimes in cdsaCspAttach Both of these issues are reliably unreliable, in that they happen every 1 out of 5 reboots or so. It took quite a bit of time to narrow things down, but by adding a LOT of syslog statements, we found that these two APIs randomly fail. Looking at the syslog and process list in ps, I see that coreservicesd is launched very soon after our daemon, so I am guessing that the Carbon File Manager uses coreservicesd. I am *guessing* that the Security framework uses securityd. Since launchd has no dependancy list, how can I tell launchd that we need these daemons launched *and ready* when our daemon loads? For now, I've hacked around these issues by doing a very kluddy for loop: for ( int i = 0; i < 5; i++ ) { // Call Alia Manager needlessly // Call cdsaCspAttach uneedlessly } But this seems just as error prone, since as machines get faster we might need to change the loop to 10 iterations, etc. Any suggestions? This email sent to site_archiver(a)lists.apple.com

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Re: Question on using launchd from a C program
by Mike Kobb 09 Jun '06

09 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Appreciate the suggestion. --Mike On Jun 8, 2006, at 6:38 PM, Andre LaBranche wrote: On Jun 8, 2006, at 6:04 PM, Mike Kobb wrote: Unfortunately, I need this to work, well, today if possible. ;-) Perhaps a loginhook / logouthook would work for the interim? Cheers, -Andre On Jun 8, 2006, at 4:37 PM, Dave Zarzycki wrote: Will you be attending WWDC? Can you wait for Leopard? davez On Jun 8, 2006, at 3:55 PM, Mike Kobb wrote: Greetings, So, I have two questions: Thanks in advance, --Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Thanks for that! I did consider the login/logout hooks, and I think they could well work, but to install them you need administrator privileges, and ideally I would not like to have to have the user have to authenticate to set up the login behavior. I think what I'm going to do instead is write a very simple faceless app that will be set as a login item. It will launch my server when it launches at login (if the user chose login-time launch), and at logout it'll find the server and tell it to quit. Should be very straightforward, and has the advantage (compared to launchd) of working on older OSes as well. I'm sorry if I mis-typed. It's login and logout that I care about. Not boot or shutdown (except insofar as shutdown implies logout). I want them to be able to choose to launch it at login, or do it manually. Then, if it's running when they log out (whichever of those two methods they chose), I want it to quit. ... http://developer.apple.com/documentation/MacOSX/Conceptual/ BPSystemStartup/Articles/CustomLogin.html Why the asymmetric requirement of launching at boot, but exiting at logout (as opposed to at boot/shutdown or login/logout)? I'm working on a MacOS preference pane that is used to configure the options of a faceless background process (a music server). This process is a BSD process for historical reasons, but will run under the privileges of a particular user, and not as root. I want to have a pop-up in the prefs pane that allows the user to choose to manually launch the server (by clicking a "Start" button in the pane, or to have the server launch at startup. Either way, I want to be sure that the server quits when they log out. It seems like launchd is likely to be what I want, but there are a few things I could use some help with. I have figured out how to create the appropriate plist to make the server launch at login and quit at shutdown, and that seems to work fine. 1) Is it possible to set up launchd to not launch the process at login, but to shut it down at logout? 2) I want this all to be controlled by my preference pane. Obviously, it's no trouble to get it to write out the required plist file, but the part I'm not sure about is how to do the equivalent of a "launchctl load" or "launchctl unload" operation. I could exec this, I guess, but I prefer to use a proper C API rather than the exec mechanism whenever I can. I couldn't make heads or tails out of launch.h, I'm afraid. This email sent to site_archiver(a)lists.apple.com

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Re: Question on using launchd from a C program
by Andre LaBranche 09 Jun '06

09 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On Jun 8, 2006, at 6:04 PM, Mike Kobb wrote: Unfortunately, I need this to work, well, today if possible. ;-) Perhaps a loginhook / logouthook would work for the interim? Cheers, -Andre On Jun 8, 2006, at 4:37 PM, Dave Zarzycki wrote: Will you be attending WWDC? Can you wait for Leopard? davez On Jun 8, 2006, at 3:55 PM, Mike Kobb wrote: Greetings, So, I have two questions: Thanks in advance, --Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/dre%40mac.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… I'm sorry if I mis-typed. It's login and logout that I care about. Not boot or shutdown (except insofar as shutdown implies logout). I want them to be able to choose to launch it at login, or do it manually. Then, if it's running when they log out (whichever of those two methods they chose), I want it to quit. ... http://developer.apple.com/documentation/MacOSX/Conceptual/ BPSystemStartup/Articles/CustomLogin.html Why the asymmetric requirement of launching at boot, but exiting at logout (as opposed to at boot/shutdown or login/logout)? I'm working on a MacOS preference pane that is used to configure the options of a faceless background process (a music server). This process is a BSD process for historical reasons, but will run under the privileges of a particular user, and not as root. I want to have a pop-up in the prefs pane that allows the user to choose to manually launch the server (by clicking a "Start" button in the pane, or to have the server launch at startup. Either way, I want to be sure that the server quits when they log out. It seems like launchd is likely to be what I want, but there are a few things I could use some help with. I have figured out how to create the appropriate plist to make the server launch at login and quit at shutdown, and that seems to work fine. 1) Is it possible to set up launchd to not launch the process at login, but to shut it down at logout? 2) I want this all to be controlled by my preference pane. Obviously, it's no trouble to get it to write out the required plist file, but the part I'm not sure about is how to do the equivalent of a "launchctl load" or "launchctl unload" operation. I could exec this, I guess, but I prefer to use a proper C API rather than the exec mechanism whenever I can. I couldn't make heads or tails out of launch.h, I'm afraid. This email sent to dre(a)mac.com This email sent to site_archiver(a)lists.apple.com

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Re: Question on using launchd from a C program
by Mike Kobb 09 Jun '06

09 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Best, --Mike On Jun 8, 2006, at 6:14 PM, Dave Zarzycki wrote: Sorry, davez On Jun 8, 2006, at 6:04 PM, Mike Kobb wrote: Unfortunately, I need this to work, well, today if possible. ;-) Thanks! --Mike On Jun 8, 2006, at 4:37 PM, Dave Zarzycki wrote: Will you be attending WWDC? Can you wait for Leopard? davez On Jun 8, 2006, at 3:55 PM, Mike Kobb wrote: Greetings, So, I have two questions: Thanks in advance, --Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Sigh. Okay, thanks. I guess no launchd for me. Nice to hear that Leopard will have some cool stuff, though! Unfortunately, you're basically going to have to wait until Leopard then. I'm sorry if I mis-typed. It's login and logout that I care about. Not boot or shutdown (except insofar as shutdown implies logout). I want them to be able to choose to launch it at login, or do it manually. Then, if it's running when they log out (whichever of those two methods they chose), I want it to quit. Obviously, this would be trivial if it were a Mac app instead of a BSD process, but unfortunately I don't have that luxury at this time... Why the asymmetric requirement of launching at boot, but exiting at logout (as opposed to at boot/shutdown or login/logout)? I'm working on a MacOS preference pane that is used to configure the options of a faceless background process (a music server). This process is a BSD process for historical reasons, but will run under the privileges of a particular user, and not as root. I want to have a pop-up in the prefs pane that allows the user to choose to manually launch the server (by clicking a "Start" button in the pane, or to have the server launch at startup. Either way, I want to be sure that the server quits when they log out. It seems like launchd is likely to be what I want, but there are a few things I could use some help with. I have figured out how to create the appropriate plist to make the server launch at login and quit at shutdown, and that seems to work fine. 1) Is it possible to set up launchd to not launch the process at login, but to shut it down at logout? 2) I want this all to be controlled by my preference pane. Obviously, it's no trouble to get it to write out the required plist file, but the part I'm not sure about is how to do the equivalent of a "launchctl load" or "launchctl unload" operation. I could exec this, I guess, but I prefer to use a proper C API rather than the exec mechanism whenever I can. I couldn't make heads or tails out of launch.h, I'm afraid. This email sent to site_archiver(a)lists.apple.com

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Re: Question on using launchd from a C program
by Dave Zarzycki 09 Jun '06

09 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Sorry, davez On Jun 8, 2006, at 6:04 PM, Mike Kobb wrote: Unfortunately, I need this to work, well, today if possible. ;-) Thanks! --Mike On Jun 8, 2006, at 4:37 PM, Dave Zarzycki wrote: Will you be attending WWDC? Can you wait for Leopard? davez On Jun 8, 2006, at 3:55 PM, Mike Kobb wrote: Greetings, So, I have two questions: Thanks in advance, --Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/zarzycki%40apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Unfortunately, you're basically going to have to wait until Leopard then. I'm sorry if I mis-typed. It's login and logout that I care about. Not boot or shutdown (except insofar as shutdown implies logout). I want them to be able to choose to launch it at login, or do it manually. Then, if it's running when they log out (whichever of those two methods they chose), I want it to quit. Obviously, this would be trivial if it were a Mac app instead of a BSD process, but unfortunately I don't have that luxury at this time... Why the asymmetric requirement of launching at boot, but exiting at logout (as opposed to at boot/shutdown or login/logout)? I'm working on a MacOS preference pane that is used to configure the options of a faceless background process (a music server). This process is a BSD process for historical reasons, but will run under the privileges of a particular user, and not as root. I want to have a pop-up in the prefs pane that allows the user to choose to manually launch the server (by clicking a "Start" button in the pane, or to have the server launch at startup. Either way, I want to be sure that the server quits when they log out. It seems like launchd is likely to be what I want, but there are a few things I could use some help with. I have figured out how to create the appropriate plist to make the server launch at login and quit at shutdown, and that seems to work fine. 1) Is it possible to set up launchd to not launch the process at login, but to shut it down at logout? 2) I want this all to be controlled by my preference pane. Obviously, it's no trouble to get it to write out the required plist file, but the part I'm not sure about is how to do the equivalent of a "launchctl load" or "launchctl unload" operation. I could exec this, I guess, but I prefer to use a proper C API rather than the exec mechanism whenever I can. I couldn't make heads or tails out of launch.h, I'm afraid. This email sent to zarzycki(a)apple.com This email sent to site_archiver(a)lists.apple.com

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