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1// Copyright 2022 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 main
16
17import (
18	"flag"
19	"fmt"
20	"io/ioutil"
21	"os"
22	"strings"
23
24	"android/soong/cmd/symbols_map/symbols_map_proto"
25	"android/soong/response"
26
27	"github.com/google/blueprint/pathtools"
28	"google.golang.org/protobuf/encoding/prototext"
29	"google.golang.org/protobuf/proto"
30)
31
32// This tool is used to extract a hash from an elf file or an r8 dictionary and store it as a
33// textproto, or to merge multiple textprotos together.
34
35func main() {
36	var expandedArgs []string
37	for _, arg := range os.Args[1:] {
38		if strings.HasPrefix(arg, "@") {
39			f, err := os.Open(strings.TrimPrefix(arg, "@"))
40			if err != nil {
41				fmt.Fprintln(os.Stderr, err.Error())
42				os.Exit(1)
43			}
44
45			respArgs, err := response.ReadRspFile(f)
46			f.Close()
47			if err != nil {
48				fmt.Fprintln(os.Stderr, err.Error())
49				os.Exit(1)
50			}
51			expandedArgs = append(expandedArgs, respArgs...)
52		} else {
53			expandedArgs = append(expandedArgs, arg)
54		}
55	}
56
57	flags := flag.NewFlagSet("flags", flag.ExitOnError)
58
59	// Hide the flag package to prevent accidental references to flag instead of flags.
60	flag := struct{}{}
61	_ = flag
62
63	flags.Usage = func() {
64		fmt.Fprintf(flags.Output(), "Usage of %s:\n", os.Args[0])
65		fmt.Fprintf(flags.Output(), "  %s -elf|-r8 <input file> [-write_if_changed] <output file>\n", os.Args[0])
66		fmt.Fprintf(flags.Output(), "  %s -merge <output file> [-write_if_changed] [-ignore_missing_files] [-strip_prefix <prefix>] [<input file>...]\n", os.Args[0])
67		fmt.Fprintln(flags.Output())
68
69		flags.PrintDefaults()
70	}
71
72	elfFile := flags.String("elf", "", "extract identifier from an elf file")
73	r8File := flags.String("r8", "", "extract identifier from an r8 dictionary")
74	merge := flags.String("merge", "", "merge multiple identifier protos")
75
76	writeIfChanged := flags.Bool("write_if_changed", false, "only write output file if it is modified")
77	ignoreMissingFiles := flags.Bool("ignore_missing_files", false, "ignore missing input files in merge mode")
78	stripPrefix := flags.String("strip_prefix", "", "prefix to strip off of the location field in merge mode")
79
80	flags.Parse(expandedArgs)
81
82	if *merge != "" {
83		// If merge mode was requested perform the merge and exit early.
84		err := mergeProtos(*merge, flags.Args(), *stripPrefix, *writeIfChanged, *ignoreMissingFiles)
85		if err != nil {
86			fmt.Fprintf(os.Stderr, "failed to merge protos: %s", err)
87			os.Exit(1)
88		}
89		os.Exit(0)
90	}
91
92	if *elfFile == "" && *r8File == "" {
93		fmt.Fprintf(os.Stderr, "-elf or -r8 argument is required\n")
94		flags.Usage()
95		os.Exit(1)
96	}
97
98	if *elfFile != "" && *r8File != "" {
99		fmt.Fprintf(os.Stderr, "only one of -elf or -r8 argument is allowed\n")
100		flags.Usage()
101		os.Exit(1)
102	}
103
104	if flags.NArg() != 1 {
105		flags.Usage()
106		os.Exit(1)
107	}
108
109	output := flags.Arg(0)
110
111	var identifier string
112	var location string
113	var typ symbols_map_proto.Mapping_Type
114	var err error
115
116	if *elfFile != "" {
117		typ = symbols_map_proto.Mapping_ELF
118		location = *elfFile
119		identifier, err = elfIdentifier(*elfFile, true)
120		if err != nil {
121			fmt.Fprintf(os.Stderr, "error reading elf identifier: %s\n", err)
122			os.Exit(1)
123		}
124	} else if *r8File != "" {
125		typ = symbols_map_proto.Mapping_R8
126		identifier, err = r8Identifier(*r8File)
127		location = *r8File
128		if err != nil {
129			fmt.Fprintf(os.Stderr, "error reading r8 identifier: %s\n", err)
130			os.Exit(1)
131		}
132	} else {
133		panic("shouldn't get here")
134	}
135
136	mapping := symbols_map_proto.Mapping{
137		Identifier: proto.String(identifier),
138		Location:   proto.String(location),
139		Type:       typ.Enum(),
140	}
141
142	err = writeTextProto(output, &mapping, *writeIfChanged)
143	if err != nil {
144		fmt.Fprintf(os.Stderr, "error writing output: %s\n", err)
145		os.Exit(1)
146	}
147}
148
149// writeTextProto writes a proto to an output file as a textproto, optionally leaving the file
150// unmodified if it was already up to date.
151func writeTextProto(output string, message proto.Message, writeIfChanged bool) error {
152	marshaller := prototext.MarshalOptions{Multiline: true}
153	data, err := marshaller.Marshal(message)
154	if err != nil {
155		return fmt.Errorf("error marshalling textproto: %w", err)
156	}
157
158	if writeIfChanged {
159		err = pathtools.WriteFileIfChanged(output, data, 0666)
160	} else {
161		err = ioutil.WriteFile(output, data, 0666)
162	}
163
164	if err != nil {
165		return fmt.Errorf("error writing to %s: %w\n", output, err)
166	}
167
168	return nil
169}
170
171// mergeProtos merges a list of textproto files containing Mapping messages into a single textproto
172// containing a Mappings message.
173func mergeProtos(output string, inputs []string, stripPrefix string, writeIfChanged bool, ignoreMissingFiles bool) error {
174	mappings := symbols_map_proto.Mappings{}
175	for _, input := range inputs {
176		mapping := symbols_map_proto.Mapping{}
177		data, err := ioutil.ReadFile(input)
178		if err != nil {
179			if ignoreMissingFiles && os.IsNotExist(err) {
180				// Merge mode is used on a list of files in the packaging directory.  If multiple
181				// goals are included on the build command line, for example `dist` and `tests`,
182				// then the symbols packaging rule for `dist` can run while a dependency of `tests`
183				// is modifying the symbols packaging directory.  That can result in a file that
184				// existed when the file list was generated being deleted as part of updating it,
185				// resulting in sporadic ENOENT errors.  Ignore them if -ignore_missing_files
186				// was passed on the command line.
187				continue
188			}
189			return fmt.Errorf("failed to read %s: %w", input, err)
190		}
191		err = prototext.Unmarshal(data, &mapping)
192		if err != nil {
193			return fmt.Errorf("failed to parse textproto %s: %w", input, err)
194		}
195		if stripPrefix != "" && mapping.Location != nil {
196			mapping.Location = proto.String(strings.TrimPrefix(*mapping.Location, stripPrefix))
197		}
198		mappings.Mappings = append(mappings.Mappings, &mapping)
199	}
200
201	return writeTextProto(output, &mappings, writeIfChanged)
202}
203