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DESCRIPTION

KTR_INFO_MASTER() declares a new master variable ktr_master_enable that is used to turn on and off event logging. KTR_INFO_MASTER_EXTERN() is a convenience macro for declaring a master variable extern.

The KTR_INFO() macro registers a new event name that will be controlled by the master enable variable. Code for logging this event will be compiled in when compile is defined. The format argument is a format string in the manner of kprintf(9) used to build the text of the event log message. The arguments required by the format string have to be specified with a type and a name. The maskbit is a bit number that determines which of the corresponding debug.ktr.*_enable sysctl's bits will enable logging of this event.

Kernel events are logged via the KTR_LOG() macro. The info parameter is an identifier of the format master_name. KTR_LOG() accepts zero or more additional arg arguments as required by the format string passed to the associated KTR_INFO() call.

The KTR_COND_LOG() macro is equivalent to KTR_LOG() except it logs only when the condition specified in cond evaluates to true.

The ktr_entries variable contains the number of entries in the ktr_buf array. These variables are mostly useful for post-mortem crash dump tools to locate the base of the circular trace buffer and its length.

The ktr_verbose variable stores the verbose flag that controls whether events are logged to the console in addition to the event buffer.

#include <sys/ktr.h>

...

#if !defined(KTR_FOO)
#define KTR_FOO		KTR_ALL
#endif
KTR_INFO_MASTER(foo);
KTR_INFO(KTR_FOO, foo, func1, 0, "func1()");
KTR_INFO(KTR_FOO, foo, func2, 1, "func2(%d)", int arg);
KTR_INFO(KTR_FOO, foo, func3, 2, "func3: arg positive: %d", int arg);

...

void
func1(void)
{
	KTR_LOG(foo_func1);
	...
}

void
func2(int arg)
{
	KTR_LOG(foo_func2, arg);
	...
}

void
func3(int arg)
{
	KTR_COND_LOG(foo_func3, arg >= 0, arg);
	...
}