avc_open(3)						     SELinux API documentation						       avc_open(3)

NAME

       avc_open, avc_destroy, avc_reset, avc_cleanup - userspace SELinux AVC setup and teardown

SYNOPSIS

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

       int avc_open(struct selinux_opt *options, unsigned nopt);

       void avc_destroy(void);

       int avc_reset(void);

       void avc_cleanup(void);

DESCRIPTION

       avc_open() initializes the userspace AVC and must be called before any other AVC operation can be performed.

       avc_destroy() destroys the userspace AVC, freeing all internal memory structures.  After this call has been made, avc_open() must be called
       again before any AVC operations can be performed.

       avc_reset() flushes the userspace AVC, causing it to forget any cached access decisions.  The userspace AVC normally  calls  this  function
       automatically when needed, see NETLINK NOTIFICATION below.

       avc_cleanup() attempts to free unused memory within the userspace AVC, but does not flush any cached access decisions.  Under normal opera-
       tion, calling this function should not be necessary.

OPTIONS

       The userspace AVC obeys callbacks set via selinux_set_callback(3), in particular the logging and audit callbacks.

       The options which may be passed to avc_open() include the following:

       AVC_OPT_SETENFORCE
	      This option forces the userspace AVC into enforcing mode if the option value is non-NULL; permissive  mode  otherwise.   The  system
	      enforcing mode will be ignored.

NETLINK NOTIFICATION

       Beginning  with	version  2.6.4, the Linux kernel supports SELinux status change notification via netlink.  Two message types are currently
       implemented, indicating changes to the enforcing mode and to the loaded policy in the kernel, respectively.  The userspace AVC listens  for
       these messages and takes the appropriate action, modifying the behavior of avc_has_perm(3) to reflect the current enforcing mode and flush-
       ing the cache on receipt of a policy load notification.	Audit messages are produced when netlink notifications are processed.

RETURN VALUE

       Functions with a return value return zero on success.  On error, -1 is returned and errno is set appropriately.

AUTHOR

       Eamon Walsh <ewalsh@tycho.nsa.gov>

SEE ALSO

       selinux(8),  avc_has_perm(3),  avc_context_to_sid(3),  avc_cache_stats(3),  avc_add_callback(3),   selinux_set_callback(3),   security_com-
       pute_av(3)

								    12 Jun 2008 						       avc_open(3)