1// Copyright 2017 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package main
6
7import (
8	"flag"
9	"fmt"
10	"log"
11	"os"
12	"strings"
13
14	"cmd/internal/buildid"
15	"cmd/internal/telemetry/counter"
16)
17
18func usage() {
19	fmt.Fprintf(os.Stderr, "usage: go tool buildid [-w] file\n")
20	flag.PrintDefaults()
21	os.Exit(2)
22}
23
24var wflag = flag.Bool("w", false, "write build ID")
25
26func main() {
27	log.SetPrefix("buildid: ")
28	log.SetFlags(0)
29	counter.Open()
30	flag.Usage = usage
31	flag.Parse()
32	counter.Inc("buildid/invocations")
33	counter.CountFlags("buildid/flag:", *flag.CommandLine)
34	if flag.NArg() != 1 {
35		usage()
36	}
37
38	file := flag.Arg(0)
39	id, err := buildid.ReadFile(file)
40	if err != nil {
41		log.Fatal(err)
42	}
43	if !*wflag {
44		fmt.Printf("%s\n", id)
45		return
46	}
47
48	// Keep in sync with src/cmd/go/internal/work/buildid.go:updateBuildID
49
50	f, err := os.Open(file)
51	if err != nil {
52		log.Fatal(err)
53	}
54	matches, hash, err := buildid.FindAndHash(f, id, 0)
55	f.Close()
56	if err != nil {
57		log.Fatal(err)
58	}
59
60	// <= go 1.7 doesn't embed the contentID or actionID, so no slash is present
61	if !strings.Contains(id, "/") {
62		log.Fatalf("%s: build ID is a legacy format...binary too old for this tool", file)
63	}
64
65	newID := id[:strings.LastIndex(id, "/")] + "/" + buildid.HashToString(hash)
66	if len(newID) != len(id) {
67		log.Fatalf("%s: build ID length mismatch %q vs %q", file, id, newID)
68	}
69
70	if len(matches) == 0 {
71		return
72	}
73
74	f, err = os.OpenFile(file, os.O_RDWR, 0)
75	if err != nil {
76		log.Fatal(err)
77	}
78	if err := buildid.Rewrite(f, matches, newID); err != nil {
79		log.Fatal(err)
80	}
81	if err := f.Close(); err != nil {
82		log.Fatal(err)
83	}
84}
85