avc_cache_stats(3)

NAME
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)