The
utility interfaces with the kernel's watchdog facility to ensure
that the system is in a working state.
If
is unable to interface with the kernel over a specific timeout,
the kernel will take actions to assist in debugging or restarting the computer.
If
-e cmd
is specified,
will attempt to execute this command with
system(3),
and only if the command returns with a zero exit code will the
watchdog be reset.
If
-e cmd
is not specified, the daemon will perform a trivial file system
check instead.
The
-s sleep
argument can be used to control the sleep period between each execution
of the check and defaults to one second.
The
-t timeout
specifies the desired timeout period in seconds.
The default timeout is 16 seconds.
One possible circumstance which will cause a watchdog timeout is an interrupt
storm.
If this occurs,
will no longer execute and thus the kernel's watchdog routines will take
action after a configurable timeout.
Upon receiving the
SIGTERM
or
SIGINT
signals,
will first instruct the kernel to no longer perform watchdog checks and then
will terminate.
The
utility recognizes the following runtime options:
-I file
Write the process ID of the
utility in the specified file.
-d
Do not fork.
When this option is specified,
will not fork into the background at startup.