diff options
Diffstat (limited to 'elf')
| -rw-r--r-- | elf/Android.bp | 1 | ||||
| -rw-r--r-- | elf/build_id_dir.go | 172 |
2 files changed, 173 insertions, 0 deletions
diff --git a/elf/Android.bp b/elf/Android.bp index 6450be137..6d3f4f0ed 100644 --- a/elf/Android.bp +++ b/elf/Android.bp @@ -20,6 +20,7 @@ bootstrap_go_package { name: "soong-elf", pkgPath: "android/soong/elf", srcs: [ + "build_id_dir.go", "elf.go", ], testSrcs: [ diff --git a/elf/build_id_dir.go b/elf/build_id_dir.go new file mode 100644 index 000000000..5fb7dda87 --- /dev/null +++ b/elf/build_id_dir.go @@ -0,0 +1,172 @@ +// Copyright 2024 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 elf + +import ( + "io/fs" + "os" + "path/filepath" + "strings" + "sync" + "time" +) + +func UpdateBuildIdDir(path string) error { + path = filepath.Clean(path) + buildIdPath := path + "/.build-id" + + // Collect the list of files and build-id symlinks. If the symlinks are + // up to date (newer than the symbol files), there is nothing to do. + var buildIdFiles, symbolFiles []string + var buildIdMtime, symbolsMtime time.Time + filepath.WalkDir(path, func(path string, entry fs.DirEntry, err error) error { + if entry == nil || entry.IsDir() { + return nil + } + info, err := entry.Info() + if err != nil { + return err + } + mtime := info.ModTime() + if strings.HasPrefix(path, buildIdPath) { + if buildIdMtime.Compare(mtime) < 0 { + buildIdMtime = mtime + } + buildIdFiles = append(buildIdFiles, path) + } else { + if symbolsMtime.Compare(mtime) < 0 { + symbolsMtime = mtime + } + symbolFiles = append(symbolFiles, path) + } + return nil + }) + if symbolsMtime.Compare(buildIdMtime) < 0 { + return nil + } + + // Collect build-id -> file mapping from ELF files in the symbols directory. + concurrency := 8 + done := make(chan error) + buildIdToFile := make(map[string]string) + var mu sync.Mutex + for i := 0; i != concurrency; i++ { + go func(paths []string) { + for _, path := range paths { + id, err := Identifier(path, true) + if err != nil { + done <- err + return + } + if id == "" { + continue + } + mu.Lock() + oldPath := buildIdToFile[id] + if oldPath == "" || oldPath > path { + buildIdToFile[id] = path + } + mu.Unlock() + } + done <- nil + }(symbolFiles[len(symbolFiles)*i/concurrency : len(symbolFiles)*(i+1)/concurrency]) + } + + // Collect previously generated build-id -> file mapping from the .build-id directory. + // We will use this for incremental updates. If we see anything in the .build-id + // directory that we did not expect, we'll delete it and start over. + prevBuildIdToFile := make(map[string]string) +out: + for _, buildIdFile := range buildIdFiles { + if !strings.HasSuffix(buildIdFile, ".debug") { + prevBuildIdToFile = nil + break + } + buildId := buildIdFile[len(buildIdPath)+1 : len(buildIdFile)-6] + for i, ch := range buildId { + if i == 2 { + if ch != '/' { + prevBuildIdToFile = nil + break out + } + } else { + if (ch < '0' || ch > '9') && (ch < 'a' || ch > 'f') { + prevBuildIdToFile = nil + break out + } + } + } + target, err := os.Readlink(buildIdFile) + if err != nil || !strings.HasPrefix(target, "../../") { + prevBuildIdToFile = nil + break + } + prevBuildIdToFile[buildId[0:2]+buildId[3:]] = path + target[5:] + } + if prevBuildIdToFile == nil { + err := os.RemoveAll(buildIdPath) + if err != nil { + return err + } + prevBuildIdToFile = make(map[string]string) + } + + // Wait for build-id collection from ELF files to finish. + for i := 0; i != concurrency; i++ { + err := <-done + if err != nil { + return err + } + } + + // Delete old symlinks. + for id, _ := range prevBuildIdToFile { + if buildIdToFile[id] == "" { + symlinkDir := buildIdPath + "/" + id[:2] + symlinkPath := symlinkDir + "/" + id[2:] + ".debug" + if err := os.Remove(symlinkPath); err != nil { + return err + } + } + } + + // Add new symlinks and update changed symlinks. + for id, path := range buildIdToFile { + prevPath := prevBuildIdToFile[id] + if prevPath == path { + continue + } + symlinkDir := buildIdPath + "/" + id[:2] + symlinkPath := symlinkDir + "/" + id[2:] + ".debug" + if prevPath == "" { + if err := os.MkdirAll(symlinkDir, 0755); err != nil { + return err + } + } else { + if err := os.Remove(symlinkPath); err != nil { + return err + } + } + + target, err := filepath.Rel(symlinkDir, path) + if err != nil { + return err + } + if err := os.Symlink(target, symlinkPath); err != nil { + return err + } + } + return nil +} |