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1// Copyright (C) 2018 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 bpf
16
17import (
18	"fmt"
19	"io"
20	"strings"
21
22	"android/soong/android"
23	_ "android/soong/cc/config"
24
25	"github.com/google/blueprint"
26)
27
28func init() {
29	android.RegisterModuleType("bpf", bpfFactory)
30	pctx.Import("android/soong/cc/config")
31}
32
33var (
34	pctx = android.NewPackageContext("android/soong/bpf")
35
36	ccRule = pctx.AndroidRemoteStaticRule("ccRule", android.RemoteRuleSupports{Goma: true},
37		blueprint.RuleParams{
38			Depfile:     "${out}.d",
39			Deps:        blueprint.DepsGCC,
40			Command:     "$ccCmd --target=bpf -c $cFlags -MD -MF ${out}.d -o $out $in",
41			CommandDeps: []string{"$ccCmd"},
42		},
43		"ccCmd", "cFlags")
44)
45
46type BpfProperties struct {
47	Srcs         []string `android:"path"`
48	Cflags       []string
49	Include_dirs []string
50}
51
52type bpf struct {
53	android.ModuleBase
54
55	properties BpfProperties
56
57	objs android.Paths
58}
59
60func (bpf *bpf) GenerateAndroidBuildActions(ctx android.ModuleContext) {
61	cflags := []string{
62		"-nostdlibinc",
63		"-O2",
64		"-isystem bionic/libc/include",
65		"-isystem bionic/libc/kernel/uapi",
66		// The architecture doesn't matter here, but asm/types.h is included by linux/types.h.
67		"-isystem bionic/libc/kernel/uapi/asm-arm64",
68		"-isystem bionic/libc/kernel/android/uapi",
69		// TODO(b/149785767): only give access to specific file with AID_* constants
70		"-I       system/core/libcutils/include",
71		"-I       system/bpf/progs/include",
72		"-I " + ctx.ModuleDir(),
73	}
74
75	for _, dir := range android.PathsForSource(ctx, bpf.properties.Include_dirs) {
76		cflags = append(cflags, "-I "+dir.String())
77	}
78
79	cflags = append(cflags, bpf.properties.Cflags...)
80
81	srcs := android.PathsForModuleSrc(ctx, bpf.properties.Srcs)
82
83	for _, src := range srcs {
84		obj := android.ObjPathWithExt(ctx, "", src, "o")
85
86		ctx.Build(pctx, android.BuildParams{
87			Rule:   ccRule,
88			Input:  src,
89			Output: obj,
90			Args: map[string]string{
91				"cFlags": strings.Join(cflags, " "),
92				"ccCmd":  "${config.ClangBin}/clang",
93			},
94		})
95
96		bpf.objs = append(bpf.objs, obj.WithoutRel())
97	}
98}
99
100func (bpf *bpf) AndroidMk() android.AndroidMkData {
101	return android.AndroidMkData{
102		Custom: func(w io.Writer, name, prefix, moduleDir string, data android.AndroidMkData) {
103			var names []string
104			fmt.Fprintln(w)
105			fmt.Fprintln(w, "LOCAL_PATH :=", moduleDir)
106			fmt.Fprintln(w)
107			for _, obj := range bpf.objs {
108				objName := name + "_" + obj.Base()
109				names = append(names, objName)
110				fmt.Fprintln(w, "include $(CLEAR_VARS)")
111				fmt.Fprintln(w, "LOCAL_MODULE := ", objName)
112				fmt.Fprintln(w, "LOCAL_PREBUILT_MODULE_FILE :=", obj.String())
113				fmt.Fprintln(w, "LOCAL_MODULE_STEM :=", obj.Base())
114				fmt.Fprintln(w, "LOCAL_MODULE_CLASS := ETC")
115				fmt.Fprintln(w, "LOCAL_MODULE_PATH := $(TARGET_OUT_ETC)/bpf")
116				fmt.Fprintln(w, "include $(BUILD_PREBUILT)")
117				fmt.Fprintln(w)
118			}
119			fmt.Fprintln(w, "include $(CLEAR_VARS)")
120			fmt.Fprintln(w, "LOCAL_MODULE := ", name)
121			fmt.Fprintln(w, "LOCAL_REQUIRED_MODULES :=", strings.Join(names, " "))
122			fmt.Fprintln(w, "include $(BUILD_PHONY_PACKAGE)")
123		},
124	}
125}
126
127// Implements OutputFileFileProducer interface so that the obj output can be used in the data property
128// of other modules.
129func (bpf *bpf) OutputFiles(tag string) (android.Paths, error) {
130	switch tag {
131	case "":
132		return bpf.objs, nil
133	default:
134		return nil, fmt.Errorf("unsupported module reference tag %q", tag)
135	}
136}
137
138var _ android.OutputFileProducer = (*bpf)(nil)
139
140func bpfFactory() android.Module {
141	module := &bpf{}
142
143	module.AddProperties(&module.properties)
144
145	android.InitAndroidArchModule(module, android.DeviceSupported, android.MultilibCommon)
146	return module
147}
148