1// Copyright (C) 2021 The Android Open Source Project
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package selinux
16
17import (
18	"os"
19	"strconv"
20
21	"github.com/google/blueprint/proptools"
22
23	"android/soong/android"
24)
25
26func init() {
27	android.RegisterModuleType("se_versioned_policy", versionedPolicyFactory)
28}
29
30type versionedPolicyProperties struct {
31	// Base cil file for versioning.
32	Base *string `android:"path"`
33
34	// Output file name. Defaults to {name} if target_policy is set, {version}.cil if mapping is set
35	Stem *string
36
37	// Target sepolicy version. Can be a specific version number (e.g. "30.0" for R), "current"
38	// (PLATFORM_SEPOLICY_VERSION), or "vendor" (BOARD_SEPOLICY_VERS). Defaults to "current"
39	Version *string
40
41	// If true, generate mapping file from given base cil file. Cannot be set with target_policy.
42	Mapping *bool
43
44	// If given, version target policy file according to base policy. Cannot be set with mapping.
45	Target_policy *string `android:"path"`
46
47	// Cil files to be filtered out by the filter_out tool of "build_sepolicy".
48	Filter_out []string `android:"path"`
49
50	// Cil files to which this mapping file depends. If specified, secilc checks whether the output
51	// file can be merged with specified cil files or not.
52	Dependent_cils []string `android:"path"`
53
54	// Whether this module is directly installable to one of the partitions. Default is true
55	Installable *bool
56
57	// install to a subdirectory of the default install path for the module
58	Relative_install_path *string
59}
60
61type versionedPolicy struct {
62	android.ModuleBase
63
64	properties versionedPolicyProperties
65
66	installSource android.Path
67	installPath   android.InstallPath
68}
69
70// se_versioned_policy generates versioned cil file with "version_policy". This can generate either
71// mapping file for public plat policies, or associate a target policy file with the version that
72// non-platform policy targets.
73func versionedPolicyFactory() android.Module {
74	m := &versionedPolicy{}
75	m.AddProperties(&m.properties)
76	android.InitAndroidArchModule(m, android.DeviceSupported, android.MultilibCommon)
77	return m
78}
79
80func (m *versionedPolicy) installable() bool {
81	return proptools.BoolDefault(m.properties.Installable, true)
82}
83
84func (m *versionedPolicy) DepsMutator(ctx android.BottomUpMutatorContext) {
85	// do nothing
86}
87
88func (m *versionedPolicy) GenerateAndroidBuildActions(ctx android.ModuleContext) {
89	version := proptools.StringDefault(m.properties.Version, "current")
90	if version == "current" {
91		version = ctx.DeviceConfig().PlatformSepolicyVersion()
92	} else if version == "vendor" {
93		version = ctx.DeviceConfig().BoardSepolicyVers()
94	}
95
96	var stem string
97	if s := proptools.String(m.properties.Stem); s != "" {
98		stem = s
99	} else if proptools.Bool(m.properties.Mapping) {
100		stem = version + ".cil"
101	} else {
102		stem = ctx.ModuleName()
103	}
104
105	out := pathForModuleOut(ctx, stem)
106	rule := android.NewRuleBuilder(pctx, ctx)
107
108	if proptools.String(m.properties.Base) == "" {
109		ctx.PropertyErrorf("base", "must be specified")
110		return
111	}
112
113	versionCmd := rule.Command().BuiltTool("version_policy").
114		FlagWithInput("-b ", android.PathForModuleSrc(ctx, *m.properties.Base)).
115		FlagWithArg("-n ", version).
116		FlagWithOutput("-o ", out)
117
118	if proptools.Bool(m.properties.Mapping) && proptools.String(m.properties.Target_policy) != "" {
119		ctx.ModuleErrorf("Can't set both mapping and target_policy")
120		return
121	}
122
123	if proptools.Bool(m.properties.Mapping) {
124		versionCmd.Flag("-m")
125	} else if target := proptools.String(m.properties.Target_policy); target != "" {
126		versionCmd.FlagWithInput("-t ", android.PathForModuleSrc(ctx, target))
127	} else {
128		ctx.ModuleErrorf("Either mapping or target_policy must be set")
129		return
130	}
131
132	if len(m.properties.Filter_out) > 0 {
133		rule.Command().BuiltTool("build_sepolicy").
134			Text("filter_out").
135			Flag("-f").
136			Inputs(android.PathsForModuleSrc(ctx, m.properties.Filter_out)).
137			FlagWithOutput("-t ", out)
138	}
139
140	if len(m.properties.Dependent_cils) > 0 {
141		rule.Command().BuiltTool("secilc").
142			Flag("-m").
143			FlagWithArg("-M ", "true").
144			Flag("-G").
145			Flag("-N").
146			FlagWithArg("-c ", strconv.Itoa(PolicyVers)).
147			Inputs(android.PathsForModuleSrc(ctx, m.properties.Dependent_cils)).
148			Text(out.String()).
149			FlagWithArg("-o ", os.DevNull).
150			FlagWithArg("-f ", os.DevNull)
151	}
152
153	rule.Build("mapping", "Versioning mapping file "+ctx.ModuleName())
154
155	if !m.installable() {
156		m.SkipInstall()
157	}
158
159	m.installSource = out
160	m.installPath = android.PathForModuleInstall(ctx, "etc", "selinux")
161	if subdir := proptools.String(m.properties.Relative_install_path); subdir != "" {
162		m.installPath = m.installPath.Join(ctx, subdir)
163	}
164	ctx.InstallFile(m.installPath, m.installSource.Base(), m.installSource)
165
166	ctx.SetOutputFiles(android.Paths{m.installSource}, "")
167}
168
169func (m *versionedPolicy) AndroidMkEntries() []android.AndroidMkEntries {
170	return []android.AndroidMkEntries{android.AndroidMkEntries{
171		OutputFile: android.OptionalPathForPath(m.installSource),
172		Class:      "ETC",
173		ExtraEntries: []android.AndroidMkExtraEntriesFunc{
174			func(ctx android.AndroidMkExtraEntriesContext, entries *android.AndroidMkEntries) {
175				entries.SetBool("LOCAL_UNINSTALLABLE_MODULE", !m.installable())
176				entries.SetPath("LOCAL_MODULE_PATH", m.installPath)
177				entries.SetString("LOCAL_INSTALLED_MODULE_STEM", m.installSource.Base())
178			},
179		},
180	}}
181}
182