Add a symbols_map tool for extracting identifiers from elf and r8 files
Add a symbols_map tool that can extract an identifiying hash from
and elf file or an r8 dictionary. The tool writes the hash to a
textproto, and also supports a merge mode to combine textprotos into
a output file for inclusion in the build artifacts.
Bug: 218888599
Test: m dist
Test: symbols_map_test.go
Change-Id: Icd3ed6e5510e058c92d97c78759e7a4cfcdbb6ca
diff --git a/cmd/symbols_map/symbols_map.go b/cmd/symbols_map/symbols_map.go
new file mode 100644
index 0000000..938446d
--- /dev/null
+++ b/cmd/symbols_map/symbols_map.go
@@ -0,0 +1,202 @@
+// Copyright 2022 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 main
+
+import (
+ "flag"
+ "fmt"
+ "io/ioutil"
+ "os"
+ "strings"
+
+ "android/soong/cmd/symbols_map/symbols_map_proto"
+ "android/soong/response"
+
+ "github.com/google/blueprint/pathtools"
+ "google.golang.org/protobuf/encoding/prototext"
+ "google.golang.org/protobuf/proto"
+)
+
+// This tool is used to extract a hash from an elf file or an r8 dictionary and store it as a
+// textproto, or to merge multiple textprotos together.
+
+func main() {
+ var expandedArgs []string
+ for _, arg := range os.Args[1:] {
+ if strings.HasPrefix(arg, "@") {
+ f, err := os.Open(strings.TrimPrefix(arg, "@"))
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err.Error())
+ os.Exit(1)
+ }
+
+ respArgs, err := response.ReadRspFile(f)
+ f.Close()
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err.Error())
+ os.Exit(1)
+ }
+ expandedArgs = append(expandedArgs, respArgs...)
+ } else {
+ expandedArgs = append(expandedArgs, arg)
+ }
+ }
+
+ flags := flag.NewFlagSet("flags", flag.ExitOnError)
+
+ // Hide the flag package to prevent accidental references to flag instead of flags.
+ flag := struct{}{}
+ _ = flag
+
+ flags.Usage = func() {
+ fmt.Fprintf(flags.Output(), "Usage of %s:\n", os.Args[0])
+ fmt.Fprintf(flags.Output(), " %s -elf|-r8 <input file> [-write_if_changed] <output file>\n", os.Args[0])
+ fmt.Fprintf(flags.Output(), " %s -merge <output file> [-write_if_changed] [-ignore_missing_files] [-strip_prefix <prefix>] [<input file>...]\n", os.Args[0])
+ fmt.Fprintln(flags.Output())
+
+ flags.PrintDefaults()
+ }
+
+ elfFile := flags.String("elf", "", "extract identifier from an elf file")
+ r8File := flags.String("r8", "", "extract identifier from an r8 dictionary")
+ merge := flags.String("merge", "", "merge multiple identifier protos")
+
+ writeIfChanged := flags.Bool("write_if_changed", false, "only write output file if it is modified")
+ ignoreMissingFiles := flags.Bool("ignore_missing_files", false, "ignore missing input files in merge mode")
+ stripPrefix := flags.String("strip_prefix", "", "prefix to strip off of the location field in merge mode")
+
+ flags.Parse(expandedArgs)
+
+ if *merge != "" {
+ // If merge mode was requested perform the merge and exit early.
+ err := mergeProtos(*merge, flags.Args(), *stripPrefix, *writeIfChanged, *ignoreMissingFiles)
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "failed to merge protos: %s", err)
+ os.Exit(1)
+ }
+ os.Exit(0)
+ }
+
+ if *elfFile == "" && *r8File == "" {
+ fmt.Fprintf(os.Stderr, "-elf or -r8 argument is required\n")
+ flags.Usage()
+ os.Exit(1)
+ }
+
+ if *elfFile != "" && *r8File != "" {
+ fmt.Fprintf(os.Stderr, "only one of -elf or -r8 argument is allowed\n")
+ flags.Usage()
+ os.Exit(1)
+ }
+
+ if flags.NArg() != 1 {
+ flags.Usage()
+ os.Exit(1)
+ }
+
+ output := flags.Arg(0)
+
+ var identifier string
+ var location string
+ var typ symbols_map_proto.Mapping_Type
+ var err error
+
+ if *elfFile != "" {
+ typ = symbols_map_proto.Mapping_ELF
+ location = *elfFile
+ identifier, err = elfIdentifier(*elfFile, true)
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "error reading elf identifier: %s\n", err)
+ os.Exit(1)
+ }
+ } else if *r8File != "" {
+ typ = symbols_map_proto.Mapping_R8
+ identifier, err = r8Identifier(*r8File)
+ location = *r8File
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "error reading r8 identifier: %s\n", err)
+ os.Exit(1)
+ }
+ } else {
+ panic("shouldn't get here")
+ }
+
+ mapping := symbols_map_proto.Mapping{
+ Identifier: proto.String(identifier),
+ Location: proto.String(location),
+ Type: typ.Enum(),
+ }
+
+ err = writeTextProto(output, &mapping, *writeIfChanged)
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "error writing output: %s\n", err)
+ os.Exit(1)
+ }
+}
+
+// writeTextProto writes a proto to an output file as a textproto, optionally leaving the file
+// unmodified if it was already up to date.
+func writeTextProto(output string, message proto.Message, writeIfChanged bool) error {
+ marshaller := prototext.MarshalOptions{Multiline: true}
+ data, err := marshaller.Marshal(message)
+ if err != nil {
+ return fmt.Errorf("error marshalling textproto: %w", err)
+ }
+
+ if writeIfChanged {
+ err = pathtools.WriteFileIfChanged(output, data, 0666)
+ } else {
+ err = ioutil.WriteFile(output, data, 0666)
+ }
+
+ if err != nil {
+ return fmt.Errorf("error writing to %s: %w\n", output, err)
+ }
+
+ return nil
+}
+
+// mergeProtos merges a list of textproto files containing Mapping messages into a single textproto
+// containing a Mappings message.
+func mergeProtos(output string, inputs []string, stripPrefix string, writeIfChanged bool, ignoreMissingFiles bool) error {
+ mappings := symbols_map_proto.Mappings{}
+ for _, input := range inputs {
+ mapping := symbols_map_proto.Mapping{}
+ data, err := ioutil.ReadFile(input)
+ if err != nil {
+ if ignoreMissingFiles && os.IsNotExist(err) {
+ // Merge mode is used on a list of files in the packaging directory. If multiple
+ // goals are included on the build command line, for example `dist` and `tests`,
+ // then the symbols packaging rule for `dist` can run while a dependency of `tests`
+ // is modifying the symbols packaging directory. That can result in a file that
+ // existed when the file list was generated being deleted as part of updating it,
+ // resulting in sporadic ENOENT errors. Ignore them if -ignore_missing_files
+ // was passed on the command line.
+ continue
+ }
+ return fmt.Errorf("failed to read %s: %w", input, err)
+ }
+ err = prototext.Unmarshal(data, &mapping)
+ if err != nil {
+ return fmt.Errorf("failed to parse textproto %s: %w", input, err)
+ }
+ if stripPrefix != "" && mapping.Location != nil {
+ mapping.Location = proto.String(strings.TrimPrefix(*mapping.Location, stripPrefix))
+ }
+ mappings.Mappings = append(mappings.Mappings, &mapping)
+ }
+
+ return writeTextProto(output, &mappings, writeIfChanged)
+}