selinux-policy/refpolicy/policy/support/loadable_module.spt

########################################
#
# Macros for switching between source policy
# and loadable policy module support
#

##############################
#
# For adding the module statement
#
define(`policy_module',`
	ifdef(`self_contained_policy',`',`
		module $1 $2;

		require {
			role system_r;
			all_kernel_class_perms
		}
	')
')

##############################
#
# For use in interfaces, to optionally insert a require block
#
define(`gen_require',`
	ifdef(`self_contained_policy',`
		ifdef(`__in_optional_policy',`
			require {
				$1
			} # end require
		')
	',`
		require {
			$1
		} # end require
	')
')

# helper function, since m4 wont expand macros
# if a line is a comment (#):
define(`policy_m4_comment',`
##### $2 depth: $1
')dnl

##############################
#
# In the future interfaces should be in loadable modules
#
# template(name,rules)
#
define(`template',` dnl
	ifdef(`$1',`errprint(__file__:__line__`: duplicate definition of $1(). Original definition on '$1. __endline__) define(`__if_error')',`define(`$1',__line__)') dnl
	`define(`$1',` dnl
	define(`policy_temp',incr(policy_call_depth)) dnl
	pushdef(`policy_call_depth',policy_temp) dnl
	undefine(`policy_temp') dnl
	policy_m4_comment(policy_call_depth,begin `$1'(dollarsstar)) dnl
	$2 dnl
	define(`policy_temp',decr(policy_call_depth)) dnl
	pushdef(`policy_call_depth',policy_temp) dnl
	undefine(`policy_temp') dnl
	policy_m4_comment(policy_call_depth,end `$1'(dollarsstar)) dnl
	'')
')

##############################
#
# In the future interfaces should be in loadable modules
#
# interface(name,rules)
#
define(`interface',` dnl
	ifdef(`$1',`errprint(__file__:__line__`: duplicate definition of $1(). Original definition on '$1. __endline__) define(`__if_error')',`define(`$1',__line__)') dnl
	`define(`$1',` dnl
	define(`policy_temp',incr(policy_call_depth)) dnl
	pushdef(`policy_call_depth',policy_temp) dnl
	undefine(`policy_temp') dnl
	policy_m4_comment(policy_call_depth,begin `$1'(dollarsstar)) dnl
	$2
	define(`policy_temp',decr(policy_call_depth)) dnl
	pushdef(`policy_call_depth',policy_temp) dnl
	undefine(`policy_temp') dnl
	policy_m4_comment(policy_call_depth,end `$1'(dollarsstar)) dnl
	'')
')

define(`policy_call_depth',0)

##############################
#
# Optional policy handling
#
define(`optional_policy',`
	ifelse(regexp(`$1',`\W'),`-1',`
		errprint(__file__:__line__`: deprecated use of module name ($1) as first parameter of optional_policy() block.' __endline__)
		optional {
			pushdef(`__in_optional_policy') dnl
			$2
			popdef(`__in_optional_policy') dnl
		ifelse(`$3',`',`',`
		} else {
			$3
		')
		}
	',`
		optional {
			pushdef(`__in_optional_policy') dnl
			$1
			popdef(`__in_optional_policy') dnl
		ifelse(`$2',`',`',`
		} else {
			$2
		')
		}
	')
')

##############################
#
# Determine if we should use the default
# tunable value as specified by the policy
# or if the override value should be used
#
define(`dflt_or_overr',`ifdef(`$1',$1,$2)')

##############################
#
# Extract booleans out of an expression.
# This needs to be reworked so expressions
# with parentheses can work.

define(`delcare_required_symbols',`
ifelse(regexp($1, `\w'), -1, `', `dnl
bool regexp($1, `\(\w+\)', `\1');
delcare_required_symbols(regexp($1, `\w+\(.*\)', `\1'))dnl
') dnl
')

##############################
#
# Tunable declaration
#
define(`gen_tunable',`
	ifdef(`self_contained_policy',`
		bool $1 dflt_or_overr(`$1'_conf,$2);
	',`
		# loadable module tunable
		# declaration will go here
		# instead of bool when
		# loadable modules support
		# tunables
		bool $1 dflt_or_overr(`$1'_conf,$2);
	')
')

##############################
#
# Tunable policy handling
#
define(`tunable_policy',`
	ifdef(`self_contained_policy',`
		if (`$1') {
			$2
		ifelse(`$3',`',`',`
		} else {
			$3
		')
		}
	',`
		# structure for tunables
		# will go here instead of a
		# conditional when loadable
		# modules support tunables
		gen_require(`
			delcare_required_symbols(`$1')
		')

		if (`$1') {
			$2
		ifelse(`$3',`',`',`
		} else {
			$3
		')
		}
	')
')