avc_open(3) [debian man page]

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)

avc_netlink_loop(3)					     SELinux API documentation					       avc_netlink_loop(3)

NAME

       avc_netlink_open,  avc_netlink_close,  avc_netlink_acquire_fd,  avc_netlink_release_fd,	avc_netlink_check_nb,  avc_netlink_loop  - SELinux
       netlink processing

SYNOPSIS

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

       int avc_netlink_open(int blocking);

       void avc_netlink_close(void);

       int avc_netlink_acquire_fd(void);

       void avc_netlink_release_fd(void);

       void avc_netlink_loop(void);

       int avc_netlink_check_nb(void);

DESCRIPTION

       These functions enable applications to handle notification of SELinux events via netlink.  The userspace AVC normally  checks  for  netlink
       messages on each call to avc_has_perm(3).  Applications may wish to override this behavior and check for notification separately, for exam-
       ple in a select(2) loop.  These functions also permit netlink monitoring without requiring a call to avc_open(3).

       avc_netlink_open()  opens  a  netlink  socket  to  receive  SELinux  notifications.   The  socket  descriptor  is  stored  internally;  use
       avc_netlink_acquire_fd(3)  to  take ownership of it in application code.  The blocking argument controls whether the O_NONBLOCK flag is set
       on the socket descriptor.  avc_open(3) calls this function internally, specifying non-blocking behavior.

       avc_netlink_close() closes the netlink socket.  This function is called automatically by avc_destroy(3).

       avc_netlink_acquire_fd() returns the netlink socket descriptor number and informs the userspace AVC not	to  check  the	socket	descriptor
       automatically on calls to avc_has_perm(3).

       avc_netlink_release_fd() returns control of the netlink socket to the userspace AVC, re-enabling automatic processing of notifications.

       avc_netlink_check_nb()  checks  the netlink socket for pending messages and processes them.  Callbacks for policyload and enforcing changes
       will be called; see selinux_set_callback(3).  This function does not block.

       avc_netlink_loop() enters a loop blocking on the netlink socket and processing messages as they	are  received.	 This  function  will  not
       return unless an error occurs on the socket, in which case the socket is closed.

RETURN VALUE

       avc_netlink_acquire_fd() returns a non-negative file descriptor number on success.  Other functions with a return value return zero on suc-
       cess.  On error, -1 is returned and errno is set appropriately.

SEE ALSO

       avc_open(3), selinux_set_callback(3), selinux(8)

								    30 Mar 2009 					       avc_netlink_loop(3)