1// Copyright 2015 Google Inc. All rights reserved.
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 android
16
17import (
18	"fmt"
19	"os"
20	"os/exec"
21	"strings"
22	"syscall"
23
24	"android/soong/env"
25)
26
27// This file supports dependencies on environment variables.  During build manifest generation,
28// any dependency on an environment variable is added to a list.  During the singleton phase
29// a JSON file is written containing the current value of all used environment variables.
30// The next time the top-level build script is run, it uses the soong_env executable to
31// compare the contents of the environment variables, rewriting the file if necessary to cause
32// a manifest regeneration.
33
34var originalEnv map[string]string
35var soongDelveListen string
36var soongDelvePath string
37var soongDelveEnv []string
38
39func init() {
40	// Delve support needs to read this environment variable very early, before NewConfig has created a way to
41	// access originalEnv with dependencies.  Store the value where soong_build can find it, it will manually
42	// ensure the dependencies are created.
43	soongDelveListen = os.Getenv("SOONG_DELVE")
44	soongDelvePath, _ = exec.LookPath("dlv")
45
46	originalEnv = make(map[string]string)
47	soongDelveEnv = []string{}
48	for _, env := range os.Environ() {
49		idx := strings.IndexRune(env, '=')
50		if idx != -1 {
51			originalEnv[env[:idx]] = env[idx+1:]
52			if env[:idx] != "SOONG_DELVE" {
53				soongDelveEnv = append(soongDelveEnv, env)
54			}
55		}
56	}
57
58	// Clear the environment to prevent use of os.Getenv(), which would not provide dependencies on environment
59	// variable values.  The environment is available through ctx.Config().Getenv, ctx.Config().IsEnvTrue, etc.
60	os.Clearenv()
61}
62
63func ReexecWithDelveMaybe() {
64	if soongDelveListen == "" {
65		return
66	}
67
68	if soongDelvePath == "" {
69		fmt.Fprintln(os.Stderr, "SOONG_DELVE is set but failed to find dlv")
70		os.Exit(1)
71	}
72	dlvArgv := []string{
73		soongDelvePath,
74		"--listen=:" + soongDelveListen,
75		"--headless=true",
76		"--api-version=2",
77		"exec",
78		os.Args[0],
79		"--",
80	}
81	dlvArgv = append(dlvArgv, os.Args[1:]...)
82	os.Chdir(absSrcDir)
83	syscall.Exec(soongDelvePath, dlvArgv, soongDelveEnv)
84	fmt.Fprintln(os.Stderr, "exec() failed while trying to reexec with Delve")
85	os.Exit(1)
86}
87
88// getenv checks either os.Getenv or originalEnv so that it works before or after the init()
89// function above.  It doesn't add any dependencies on the environment variable, so it should
90// only be used for values that won't change.  For values that might change use ctx.Config().Getenv.
91func getenv(key string) string {
92	if originalEnv == nil {
93		return os.Getenv(key)
94	} else {
95		return originalEnv[key]
96	}
97}
98
99func EnvSingleton() Singleton {
100	return &envSingleton{}
101}
102
103type envSingleton struct{}
104
105func (c *envSingleton) GenerateBuildActions(ctx SingletonContext) {
106	envDeps := ctx.Config().EnvDeps()
107
108	envFile := PathForOutput(ctx, ".soong.environment")
109	if ctx.Failed() {
110		return
111	}
112
113	data, err := env.EnvFileContents(envDeps)
114	if err != nil {
115		ctx.Errorf(err.Error())
116	}
117
118	err = WriteFileToOutputDir(envFile, data, 0666)
119	if err != nil {
120		ctx.Errorf(err.Error())
121	}
122
123	ctx.AddNinjaFileDeps(envFile.String())
124}
125