Watchdog

From AwkwardTV
Revision as of 07:21, 15 July 2007 by XqvBvg (talk | contribs)
Jump to: navigation, search

cheap tenuate lortab online kyocera ringtones cheap sildenafil order vicodin buy alprazolam sharp ringtones free punk ringtones but vigrx meridia qwest ringtones nextel ringtones cyclobenzaprine online jazz ringtones buy zyban cialis diazepam online diethylpropion online free kyocera ringtones zanaflex online cheap ultram ambien online mp3 ringtones free music ringtones cheap zoloft lortab online cheap xanax cheap vigrx albuterol online free kyocera ringtones free mono ringtones lipitor online propecia online xanax online propecia online ericsson ringtones order ortho hgh online tracfone ringtones clomid online tramadol online vigrx online motorola ringtones real ringtones cheap meridia cheap ortho free polyphonic ringtones cheap ultracet free nextel ringtones cheap lisinopril free sony ericsson ringtones sony ericsson ringtones alltel ringtones free nokia ringtones cialis online viagra online free real ringtones celexa online valium online free nokia ringtones levitra online nokia ringtones online nexium cingular ringtones free polyphonic ringtones buy diethylpropion tenuate online cheap cialis jazz ringtones online pharmacy but phentermine motorola ringtones levitra online free mono ringtones zyban online free samsung ringtones free mp3 ringtones soma online cheap ultram ambien online vicodin online cheap vicodin funny ringtones zanaflex albuterol online cheap nexium buy propecia ambien free nokia ringtones alprazolam online cheap viagra ultracet online cheap hoodia cyclobenzaprine online free free ringtones cheap phentermine cheap soma free real ringtones free jazz ringtones vicodin online zyban online free ericsson ringtones sagem ringtones diazepam online free sharp ringtones free cingular ringtones cheap adipex free verizon ringtones qwest ringtones cheap clonazepam zanaflex online free mtv ringtones free mtv ringtones free kyocera ringtones free sony ericsson ringtones cheap tenuate free real ringtones valium online cheap paxil cheap didrex cheap sildenafil nextel ringtones free midi ringtones cheap ativan online xanax buy cyclobenzaprine lorazepam online free alltel ringtones didrex online free mp3 ringtones free cingular ringtones tracfone ringtones buy xanax tracfone ringtones order norco fioricet online lorazepam online free free ringtones cheap viagra free wwe ringtones xanax online cheap zoloft free free ringtones but sildenafil cheap xenical samsung ringtones prozac online buy ultracet buy norco cheap lipitor free motorola ringtones sagem ringtones buy meridia but hydrocodone diazepam online ativan online norco online cheap prozac free sonyericsson ringtones qwest ringtones cheap lisinopril cheap didrex ultram online cialis cheap alprazolam nextel ringtones cool ringtones lortab online free nextel ringtones zyban online pharmacy online online cheap xanax ativan sprint ringtones ativan online free sprint ringtones cheap wellbutrin zanaflex online carisoprodol online propecia online prozac online valium online cheap xanax motorola ringtones but ortho wellbutrin online cheap levitra fioricet samsung ringtones cheap ortho free cool ringtones lorazepam online celexa online tramadol online free polyphonic ringtones cheap zanaflex nokia ringtones ortho online samsung ringtones cheap soma ===What is Watchdog===

Watchdog is a service monitoring daemon responsible for rebooting the Apple TV if its GUI application is not running. Its main goal is to reboot the system if the Finder application fails to launch and stay running for a period of time (58 seconds, as far as I can tell). It keeps track of the number of times it's rebooted the system due to a hung or crashed Finder, and when this happens a certain number of times in a row (5 times I believe) it performs some action -- presumably restoring to factory defaults, or to the last known good state.

There's a kext called AppleTCOWatchdog.kext in the /System/Library/Extensions/ folder.

Brief Watchdog Background

Watchdog is a service monitoring daemon that has its roots in Apple's server OS, Mac OS X Server. Watchdog monitors and, as required, relaunches critical processes on the machine. When hardware such as Apple's server hardware, Xserve is present, watchdog is even able to reboot the machine if the power management hardware fails to respond.

This should not be confused with the "watchdog" program from OS X 10.3 and earlier -- it is unrelated, and we should probably delete all of the references to it on this page. :/

The Ripstop Daemon

Ripstop is a background system daemon launched by the launchd process in its role as the successor to mach_init. Ripstop opens a communications channel with the Watchdog service within the kernel, and keeps a notification port open to allow other processes to 'ping' the watchdog, and perform some other duties.

Ripstop Details

Ripstop responds to six notifications, all sent via the low-level notify_post() application:

  • com.apple.riptide.heartbeat
  • com.apple.riptide.start
  • com.apple.riptide.stop
  • com.apple.ripstop.query
  • com.apple.ripstop.debug

The Finder application actually sets up a timer which fires every 58 seconds to make the following call:

notify_post( "com.apple.riptide.heartbeat" );

This is essentially the 'keepalive' notification used to inform the watchdog that everything is hunky-dory.

Upon launch, ripstop switches to the Frontrow user