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

Re: HFS + and creating a big file
by John Francini 10 Jun '06

10 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.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

1 0

HFS + and creating a big file
by Marc Van Olmen 10 Jun '06

10 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com hi, Any trick on how to prevent this from happening? regars, marc _______________________________________________ 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 need to create a big file (20GB), the contents is not important, will fill that in later, just the file size... When I try to do this with lseek and then write one byte. as soon I close the file, it takes a few minutes because it looks like the OS is filling up the rest with 0x00 bytes during close or flush. File system is HFS+ This email sent to site_archiver(a)lists.apple.com

1 0

Re: Question on using launchd from a C program
by Paul Nelson 10 Jun '06

10 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Thread-index: AcaMQE+5jlf2KvgzEdqDHQAWy4i6sA== Thread-topic: Question on using launchd from a C program User-agent: Microsoft-Entourage/11.2.3.060209 1) When multiple users are logged in to the "console" (fast user switching), you get the proper events as the users change: > com.apple.sessionDidMoveOffConsole - for fast user switching > com.apple.sessionDidMoveOnConsole - for fast user switching 2) Users that log in using ssh don't have things run from loginwindow.plist (login items). This is also why I suggested monitoring ALL events, so that behaviors like ssh users can be verified. It should be a piece of cake to avoid interference from ssh users. Paul > From: Andrew White <andrew.white(a)nicta.com.au> > Date: Sat, 10 Jun 2006 11:19:21 +1000 > To: Mike Kobb <mjkobb(a)alum.mit.edu> > Cc: <darwin-dev(a)lists.apple.com> > Subject: Re: Question on using launchd from a C program > > As a stupid question, have you handled two unusual cases: > > (1) There are multiple users logged in? > > (2) What happens when a user logs in via ssh, independent of the normal > display? The two possible problem cases here are logging in when no-one is > logged in and having the display user log out while someone is still logged > in via ssh. > > -- > Andrew White _______________________________________________ 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

1 0

kqueue - supported filesystems?
by Jim Correia 10 Jun '06

10 Jun '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com The kqueue man page says: Which filesystems are supported? Thanks, Jim _______________________________________________ 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… Not all filesystem types support kqueue-style notifications. And even some that do, like some remote filesystems, may only support a subset of the notification semantics described here. How can I determine at runtime whether a file system is supported? (And if the notification semantics are what I need?) This email sent to site_archiver(a)lists.apple.com

1 0

Re: Question on using launchd from a C program
by Andrew White 10 Jun '06

10 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) Thanks for that! Pretty interesting. As a stupid question, have you handled two unusual cases: (1) There are multiple users logged in? -- Andrew White -------------------------------------------------------------------------- This email and any attachments may be confidential. They may contain legally privileged information or copyright material. You should not read, copy, use or disclose them without authorisation. If you are not an intended recipient, please contact us at once by return email and then delete both messages. We do not accept liability in connection with computer virus, data corruption, delay, interruption, unauthorised access or unauthorised amendment. This notice should not be removed. _______________________________________________ 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… Mike Kobb wrote: As it happens, since I really didn't want to introduce big Mac dependencies into the server code, I ended up writing a tiny little faceless background "helper" app that launches the server when it starts and quits it when it exits. Because it's a MacOS app and not a BSD daemon-type process like the server, I can add it to the Login Items, and that works beautifully for me. The helper reads a preference set by my prefs pane so it knows whether to launch the server when it starts or let the user do it manually... (2) What happens when a user logs in via ssh, independent of the normal display? The two possible problem cases here are logging in when no-one is logged in and having the display user log out while someone is still logged in via ssh. This email sent to site_archiver(a)lists.apple.com

1 0

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 Thanks for that! Pretty interesting. Thanks to all for your help! --Mike On Jun 9, 2006, at 6:20 AM, Paul Nelson wrote: Add this, and the associated observeNotices to your background app: com.apple.sessionDidMoveOffConsole - for fast user switching com.apple.sessionDidMoveOnConsole - for fast user switching 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/site_archiver%40lists.app… As it happens, since I really didn't want to introduce big Mac dependencies into the server code, I ended up writing a tiny little faceless background "helper" app that launches the server when it starts and quits it when it exits. Because it's a MacOS app and not a BSD daemon-type process like the server, I can add it to the Login Items, and that works beautifully for me. The helper reads a preference set by my prefs pane so it knows whether to launch the server when it starts or let the user do it manually... It's probably a real sin to suggest this, but since you are waiting for lepoard anyway.... [[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 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.... This email sent to site_archiver(a)lists.apple.com

1 0

Re: Very early load and usage of higher level APIs
by Dave Zarzycki 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 5:02 AM, Shaun Wexler wrote: As Kevin said, please file bugs. This isn't your fault. #include <mach/mach_time.h> #include <servers/bootstrap.h> char *servicename[] = { "com.apple.CoreServices.coreservicesd", "com.apple.windowserver.active" }; Please, please file bugs. Thanks! :-) davez _______________________________________________ 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… Both of these issues are reliably unreliable, in that they happen every 1 out of 5 reboots or so. 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])); For many different reasons, I would not recommend the above strategy. If you must workaround OS bugs, I'd much rather advise putting a blatant sleep(10) at the top of your main(). This email sent to site_archiver(a)lists.apple.com

1 0

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 9:08 AM, Eric Albert wrote: Carbon is not daemon-safe, so you're SOL there. Tech Note 2083: <http://developer.apple.com/technotes/tn2005/tn2083.html> _______________________________________________ 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… The Alias Manager is part of Core Services, so it should be OK. But it does require that coreservicesd be up and running.... Good, nice to know. BTW, I compiled that bootstrap code and it works just fine with my daemon, which also loads early [31]. -- Shaun Wexler MacFOH http://www.macfoh.com This email sent to site_archiver(a)lists.apple.com

1 0

Re: Very early load and usage of higher level APIs
by Dave Zarzycki 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 5:50 AM, Shaun Wexler wrote: On Jun 9, 2006, at 1:28 AM, Kevin Van Vechten wrote: Any appearance of load order is purely coincidental. davez _______________________________________________ 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 Possible workaround: put it into /etc/mach_init.d/ zzzz.my.daemon.plist This email sent to site_archiver(a)lists.apple.com

1 0

Re: Very early load and usage of higher level APIs
by Eric Albert 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 5:02 AM, Shaun Wexler wrote: 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> -Eric _______________________________________________ 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 Alias Manager is part of Core Services, so it should be OK. But it does require that coreservicesd be up and running.... This email sent to site_archiver(a)lists.apple.com

1 0