avc_cache_stats man page

avc_cache_stats, avc_av_stats, avc_sid_stats — obtain userspace SELinux AVC statistics

Synopsis

#include <selinux/selinux.h>
#include <selinux/avc.h>

void avc_av_stats(void);

void avc_sid_stats(void);

void avc_cache_stats(struct avc_cache_stats *stats);

Description

The userspace AVC maintains two internal hash tables, one to store security ID's and one to cache access decisions.

avc_av_stats() and avc_sid_stats() produce log messages indicating the status of the access decision and SID tables, respectively. The messages contain the number of entries in the table, number of hash buckets and number of buckets used, and maximum number of entries in a single bucket.

avc_cache_stats() populates a structure whose fields reflect cache activity:

struct avc_cache_stats {
	unsigned	entry_lookups;
	unsigned	entry_hits;
	unsigned	entry_misses;
	unsigned	entry_discards;
	unsigned	cav_lookups;
	unsigned	cav_hits;
	unsigned	cav_probes;
	unsigned	cav_misses;
};
entry_lookups
Number of queries made.
entry_hits
Number of times a decision was found in the aeref argument.
entry_misses
Number of times a decision was not found in the aeref argument.
entry_discards
Number of times a decision was not found in the aeref argument and the aeref argument was non-NULL.
cav_lookups
Number of cache lookups.
cav_hits
Number of cache hits.
cav_misses
Number of cache misses.
cav_probes
Number of entries examined while searching the cache.

Notes

When the cache is flushed as a result of a call to avc_reset() or a policy change notification, the statistics returned by avc_cache_stats() are reset to zero. The SID table, however, is left unchanged.

When a policy change notification is received, a call to avc_av_stats() is made before the cache is flushed.

Author

Eamon Walsh <ewalsh@tycho.nsa.gov>

See Also

avc_init(3), avc_has_perm(3), avc_context_to_sid(3), avc_add_callback(3), selinux(8)

Referenced By

avc_add_callback(3), avc_context_to_sid(3), avc_has_perm(3), avc_open(3).

avc_av_stats(3) and avc_sid_stats(3) are aliases of avc_cache_stats(3).

27 May 2004 SELinux API documentation