Add path interposer
This will allow us to track (and eventually limit) the commands that the
build references via $PATH. These are mostly implicit dependencies on
the host system -- for Linux, we assume something similar to Ubuntu
14.04 with a few extra packages, but this will let us better define
that.
This will not catch uses of tools with absolute paths (/bin/bash, etc),
but most uses shouldn't be relying on absolute path names anyways.
Adds ~400ms on the first startup, ~140ms on subsequent runs, and
overhead of a few ms for every forwarded execution.
Test: m
Test: build/soong/build_test.bash
Test: Add `gcc --version`, TEMPORARY_DISABLE_PATH_RESTRICTIONS=true m
Change-Id: Id68cbb1c8ceef65bbbb10751e83722c7662d2351
diff --git a/ui/build/path.go b/ui/build/path.go
new file mode 100644
index 0000000..52658ef
--- /dev/null
+++ b/ui/build/path.go
@@ -0,0 +1,149 @@
+// Copyright 2018 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package build
+
+import (
+ "fmt"
+ "io/ioutil"
+ "os"
+ "path/filepath"
+ "strings"
+
+ "github.com/google/blueprint/microfactory"
+
+ "android/soong/ui/build/paths"
+)
+
+func parsePathDir(dir string) []string {
+ f, err := os.Open(dir)
+ if err != nil {
+ return nil
+ }
+ defer f.Close()
+
+ if s, err := f.Stat(); err != nil || !s.IsDir() {
+ return nil
+ }
+
+ infos, err := f.Readdir(-1)
+ if err != nil {
+ return nil
+ }
+
+ ret := make([]string, 0, len(infos))
+ for _, info := range infos {
+ if m := info.Mode(); !m.IsDir() && m&0111 != 0 {
+ ret = append(ret, info.Name())
+ }
+ }
+ return ret
+}
+
+func SetupPath(ctx Context, config Config) {
+ if config.pathReplaced {
+ return
+ }
+
+ ctx.BeginTrace("path")
+ defer ctx.EndTrace()
+
+ origPath, _ := config.Environment().Get("PATH")
+ myPath := filepath.Join(config.OutDir(), ".path")
+ interposer := myPath + "_interposer"
+
+ var cfg microfactory.Config
+ cfg.Map("android/soong", "build/soong")
+ cfg.TrimPath, _ = filepath.Abs(".")
+ if _, err := microfactory.Build(&cfg, interposer, "android/soong/cmd/path_interposer"); err != nil {
+ ctx.Fatalln("Failed to build path interposer:", err)
+ }
+
+ if err := ioutil.WriteFile(interposer+"_origpath", []byte(origPath), 0777); err != nil {
+ ctx.Fatalln("Failed to write original path:", err)
+ }
+
+ entries, err := paths.LogListener(ctx.Context, interposer+"_log")
+ if err != nil {
+ ctx.Fatalln("Failed to listen for path logs:", err)
+ }
+
+ go func() {
+ for log := range entries {
+ curPid := os.Getpid()
+ for i, proc := range log.Parents {
+ if proc.Pid == curPid {
+ log.Parents = log.Parents[i:]
+ break
+ }
+ }
+ procPrints := []string{
+ "See https://android.googlesource.com/platform/build/+/master/Changes.md#PATH_Tools for more information.",
+ }
+ if len(log.Parents) > 0 {
+ procPrints = append(procPrints, "Process tree:")
+ for i, proc := range log.Parents {
+ procPrints = append(procPrints, fmt.Sprintf("%s→ %s", strings.Repeat(" ", i), proc.Command))
+ }
+ }
+
+ config := paths.GetConfig(log.Basename)
+ if config.Error {
+ ctx.Printf("Disallowed PATH tool %q used: %#v", log.Basename, log.Args)
+ for _, line := range procPrints {
+ ctx.Println(line)
+ }
+ } else {
+ ctx.Verbosef("Unknown PATH tool %q used: %#v", log.Basename, log.Args)
+ for _, line := range procPrints {
+ ctx.Verboseln(line)
+ }
+ }
+ }
+ }()
+
+ ensureEmptyDirectoriesExist(ctx, myPath)
+
+ var execs []string
+ for _, pathEntry := range filepath.SplitList(origPath) {
+ if pathEntry == "" {
+ // Ignore the current directory
+ continue
+ }
+ // TODO(dwillemsen): remove path entries under TOP? or anything
+ // that looks like an android source dir? They won't exist on
+ // the build servers, since they're added by envsetup.sh.
+ // (Except for the JDK, which is configured in ui/build/config.go)
+
+ execs = append(execs, parsePathDir(pathEntry)...)
+ }
+
+ allowAllSymlinks := config.Environment().IsEnvTrue("TEMPORARY_DISABLE_PATH_RESTRICTIONS")
+ for _, name := range execs {
+ if !paths.GetConfig(name).Symlink && !allowAllSymlinks {
+ continue
+ }
+
+ err := os.Symlink("../.path_interposer", filepath.Join(myPath, name))
+ // Intentionally ignore existing files -- that means that we
+ // just created it, and the first one should win.
+ if err != nil && !os.IsExist(err) {
+ ctx.Fatalln("Failed to create symlink:", err)
+ }
+ }
+
+ myPath, _ = filepath.Abs(myPath)
+ config.Environment().Set("PATH", myPath)
+ config.pathReplaced = true
+}