site_archiver@lists.apple.com Delivered-To: darwin-dev@lists.apple.com On May 20, 2009, at 10:38 AM, Matthew Mashyna wrote: Eric Matt On Mar 18, 2009, at 6:03 PM, Ethan Bold wrote: -Ethan On Mar 18, 2009, at 1:14 PM, Brian Bergstrand wrote: On Mar 18, 2009, at 8:07 PM, Ethan Bold wrote: Hi Matt- What about the following constants: #define kIOMessageCanSystemPowerOff iokit_common_msg(0x240) #define kIOMessageSystemWillPowerOff iokit_common_msg(0x250) #define kIOMessageSystemWillNotPowerOff iokit_common_msg(0x260) They exist in the headers so one assumes they will be sent. Brian Bergstrand <http://www.bergstrand.org/brian/> PGP Key ID: 0xB6C7B6A2 _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/eric.gouriou%40pobox.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.appl... My client asked me to take this issue up again and I found an acceptable solution. To recap... I have a Cocoa based daemon that monitors, uh, "stuff" on client computers. This daemon regularly checks in with a server to report the client's status. The problem I was having was that when the system shuts down, the daemon wasn't able to get the notification that a shutdown was imminent and report the shutdown to the server. I got a lot of suggestions about using IOKit and distributed notifications. None of that stuff worked when my daemon was launched from launchd. I started looking at catching the SIGTERM. I wasn't able to catch it on shutdown until... I changed the launch daemon plist to include this option: HopefullyExitsFirst When HopefullyExitsFirst is turned on, the shutdown waits for my daemon to exit and voila! I get the signal and have time to report the shutdown. At least I think it waits. I'm not completely sure but I get the result I am looking for. Is it acceptable to slowdown every shutdown ? How long does it take for the daemon to handle the SIGTERM and exit ? ---------------- HopefullyExitsFirst <boolean> This optional key causes programs to exit earlier during system shutdown. This key exists because some jobs do more than flush buffers and exit like they're supposed to. The use of this key should be considered a temporary solution until the software can be changed to only flush dirty buffers and then exit. ---------------- The use of that key is discouraged and considered a kludge. I know that Damien would love to get rid of it. The semantics (carefully left unspecified) may also change. "earlier" is pretty vague, a 10ms headstart on the SIGTERM could be what this will mean in a future release. The not HopefullyExitsFirst case may not work for this daemon due to dependencies on other daemons which are being shutdown concurrently. A solution would be to stop relying on those services, or at the very least to stop relying on those services to handle the shutdown case. Potential solutions: - there could be a simplistic BSD-only daemon which just invokes sigwait() and notifies the server upon reception of SIGTERM. - the server could understand that a severed connection implies a shutdown. - the daemon register a (WAN) Bonjour service and rely on mDNSResponder to handle the unregistration at shutdown for you. It's difficult to provide advice given the dearth of information about this daemon. In general the mention of a "Cocoa based [launch] daemon" makes me cringe. Did you mean a Foundation-based daemon ? At the very least I'd encourage you to file an enhancement request stating your needs and constraints. Though your assumption is reasonable, those constants don't work. IOKit doesn't send out messages for those. IOKit does not provide any notifications of system shutdown. The IORegisterForSystemPower() API call that you make below only refers to system sleep & wake power events, not shutdown events - the argument messageType may be kIOPMMessageCanSystemSleep, kIOPMMessageSystemWillSleep, kIOPMMessageSystemWillNotSleep, kIOPMMessageSystemHasPoweredOn, kIOPMMessageSystemWillPowerOn. That's all - no messages sent on shutdown. This email sent to eric.gouriou@pobox.com This email sent to site_archiver@lists.apple.com