.TH "seccomp_arch_add" 3 "26 November 2012" "paul@paul-moore.com" "libseccomp Documentation"
.\" //////////////////////////////////////////////////////////////////////////
.SH NAME
.\" //////////////////////////////////////////////////////////////////////////
seccomp_arch_add, seccomp_arch_remove, seccomp_arch_exist, seccomp_arch_native \- Manage seccomp filter architectures
.\" //////////////////////////////////////////////////////////////////////////
.SH SYNOPSIS
.\" //////////////////////////////////////////////////////////////////////////
.nf
.B #include <seccomp.h>
.sp
.B typedef void * scmp_filter_ctx;
.sp
.B #define SCMP_ARCH_NATIVE
.B #define SCMP_ARCH_X86
.B #define SCMP_ARCH_X86_64
.sp
.BI "uint32_t seccomp_arch_native();"
.BI "int seccomp_arch_exist(const scmp_filter_ctx " ctx ", uint32_t " arch_token ");"
.BI "int seccomp_arch_add(scmp_filter_ctx " ctx ", uint32_t " arch_token ");"
.BI "int seccomp_arch_remove(scmp_filter_ctx " ctx ", uint32_t " arch_token ");"
.sp
Link with \fI\-lseccomp\fP.
.fi
.\" //////////////////////////////////////////////////////////////////////////
.SH DESCRIPTION
.\" //////////////////////////////////////////////////////////////////////////
.P
The
.BR seccomp_arch_exist ()
function tests to see if a given architecture has been added to the seccomp
filter in
.I ctx
, where the
.BR seccomp_arch_add ()
and
.BR seccomp_arch_remove ()
add and remove, respectively, architectures from the seccomp filter.  In all
three functions, the architecture values given in
.I arch_token
should be the
.BR SCMP_ARCH_*
defined constants; with the
.BR SCMP_ARCH_NATIVE
constant always referring to the native compiled architecture.  The
.BR seccomp_arch_native ()
function returns the system's architecture such that it will match one of the
.BR SCMP_ARCH_*
constants.
.P
When a seccomp filter is initialized with the call to
.BR seccomp_init (3)
the native architecture is automatically added to the filter.  If you want to
remove the native architecture from the filter, you first need to add another
architecture to the filter as a seccomp filter must contain at least one
architecture at all times.  After you have added a second architecture to the
seccomp filter, you can remove the native architecture.
.P
When adding a new architecture to an existing filter, the existing rules will
not be added to the new architecture.  However, rules added after adding the
new architecture will be added to all of the architectures in the filter.
.\" //////////////////////////////////////////////////////////////////////////
.SH RETURN VALUE
.\" //////////////////////////////////////////////////////////////////////////
The
.BR seccomp_arch_add ()
and
.BR seccomp_arch_remove ()
functions return zero on success, negative errno values on failure.  The
.BR seccomp_arch_exist ()
function returns zero if the architecture exists, \-EEXIST if it does not, and
other negative errno values on failure.
.\" //////////////////////////////////////////////////////////////////////////
.SH EXAMPLES
.\" //////////////////////////////////////////////////////////////////////////
.nf
#include <seccomp.h>

int main(int argc, char *argv[])
{
	int rc = \-1;
	scmp_filter_ctx ctx;

	ctx = seccomp_init(SCMP_ACT_KILL);
	if (ctx == NULL)
		goto out;

	if (seccomp_arch_exist(ctx, SCMP_ARCH_X86) == \-EEXIST) {
		rc = seccomp_arch_add(ctx, SCMP_ARCH_X86);
		if (rc != 0)
			goto out_all;
		rc = seccomp_arch_remove(ctx, SCMP_ARCH_NATIVE);
		if (rc != 0)
			goto out_all;
	}

	/* ... */

out:
	seccomp_release(ctx);
	return \-rc;
}
.fi
.\" //////////////////////////////////////////////////////////////////////////
.SH NOTES
.\" //////////////////////////////////////////////////////////////////////////
.P
While the seccomp filter can be generated independent of the kernel, kernel
support is required to load and enforce the seccomp filter generated by
libseccomp.
.P
The libseccomp project site, with more information and the source code
repository, can be found at http://libseccomp.sf.net.  This library is currently
under development, please report any bugs at the project site or directly to
the author.
.\" //////////////////////////////////////////////////////////////////////////
.SH AUTHOR
.\" //////////////////////////////////////////////////////////////////////////
Paul Moore <paul@paul-moore.com>
.\" //////////////////////////////////////////////////////////////////////////
.SH SEE ALSO
.\" //////////////////////////////////////////////////////////////////////////
.BR seccomp_init (3),
.BR seccomp_reset (3),
.BR seccom_merge (3)