.\" Hey Emacs! This file is -*- nroff -*- source.
.\"
.\" Author: Eamon Walsh (ewalsh@tycho.nsa.gov) 2007
.TH "selabel_open" "3" "18 Jun 2007" "" "SELinux API documentation"
.SH "NAME"
selabel_open, selabel_close \- userspace SELinux labeling interface
.
.SH "SYNOPSIS"
.B #include <selinux/selinux.h>
.br
.B #include <selinux/label.h>
.sp
.BI "struct selabel_handle *selabel_open(int " backend , 
.in +\w'struct selabel_handle *selabel_open('u
.BI "struct selinux_opt *" options ,
.br
.BI "unsigned " nopt ");"
.in
.sp
.BI "void selabel_close(struct selabel_handle *" hnd ");"
.
.SH "DESCRIPTION"
.BR selabel_open ()
is used to initialize a labeling handle to be used for lookup operations.  The 
.I backend
argument specifies which backend is to be opened; the list of current backends appears in 
.B BACKENDS
below.

The 
.I options
argument should be NULL or a pointer to an array of 
.B selinux_opt
structures of length
.IR nopt :

.RS
.ta 4n 16n 24n
.nf
struct selinux_opt {
	int	type;
	const char	*value;
};
.fi
.ta
.RE

The available option types are described in 
.B GLOBAL OPTIONS
below as well as in the documentation for each individual backend.  The return value on success is a non-NULL value for use in subsequent label operations.

.BR selabel_close ()
terminates use of a handle, freeing any internal resources associated with it.  After this call has been made, the handle must not be used again.
.
.SH "GLOBAL OPTIONS"
Global options which may be passed to
.BR selabel_open ()
include the following:
.
.TP
.B SELABEL_OPT_UNUSED
The option with a type code of zero is a no-op.  Thus an array of options may be initizalized to zero and any untouched elements will not cause an error.
.TP
.B SELABEL_OPT_VALIDATE
A non-null value for this option enables context validation.  By default,
.BR security_check_context (3)
is used; a custom validation function can be provided via
.BR selinux_set_callback (3).
Note that an invalid context may not be treated as an error unless it is actually encountered during a lookup operation.
.
.SH "BACKENDS"
.TP
.B SELABEL_CTX_FILE
File contexts backend, described in 
.BR selabel_file (5).
.TP
.B SELABEL_CTX_MEDIA
Media contexts backend, described in 
.BR selabel_media (5).
.TP
.B SELABEL_CTX_X
X Windows contexts backend, described in 
.BR selabel_x (5).
.TP
.B SELABEL_CTX_DB
Database objects contexts backend, described in
.BR selabel_db (5).
.
.SH "RETURN VALUE"
A non-NULL handle value is returned on success.  On error, NULL is returned and
.I errno
is set appropriately.
.
.SH "AUTHOR"
Eamon Walsh <ewalsh@tycho.nsa.gov>
.
.SH "SEE ALSO"
.ad l
.nh
.BR selabel_lookup (3),
.BR selabel_stats (3),
.BR selinux_set_callback (3),
.BR selinux (8)