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Reusable flags package
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Signed-off-by: Chris Koch <[email protected]>
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@hugelgupf
hugelgupf committed Feb 18, 2024
1 parent a0352c1 commit 5fc8554
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Showing 5 changed files with 252 additions and 166 deletions.
203 changes: 41 additions & 162 deletions cmd/mkuimage/main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -16,78 +16,16 @@ import (
"strings"

"github.com/dustin/go-humanize"
"github.com/hugelgupf/go-shlex"
"github.com/u-root/gobusybox/src/pkg/golang"
"github.com/u-root/gobusybox/src/pkg/uflag"
"github.com/u-root/mkuimage/uimage"
"github.com/u-root/mkuimage/uimage/builder"
"github.com/u-root/mkuimage/uimage/initramfs"
"github.com/u-root/mkuimage/uimage/uflags"
"github.com/u-root/uio/llog"
)

// multiFlag is used for flags that support multiple invocations, e.g. -files.
type multiFlag []string

func (m *multiFlag) String() string {
return fmt.Sprint(*m)
}

// Set implements flag.Value.Set.
func (m *multiFlag) Set(value string) error {
*m = append(*m, value)
return nil
}

var (
errEmptyFilesArg = errors.New("empty argument to -files")
)

// Flags for u-root builder.
var (
build, format, tmpDir, basePath, outputPath *string
uinitCmd, initCmd *string
defaultShell *string
useExistingInit *bool
noCommands *bool
extraFiles multiFlag
shellbang *bool
// For the new "filepath only" logic.
urootSourceDir *string
)

func init() {
var sh string
switch golang.Default().GOOS {
case "plan9":
sh = ""
default:
sh = "elvish"
}

build = flag.String("build", "gbb", "u-root build format (e.g. bb/gbb or binary).")
format = flag.String("format", "cpio", "Archival format.")

tmpDir = flag.String("tmpdir", "", "Temporary directory to put binaries in.")

basePath = flag.String("base", "", "Base archive to add files to. By default, this is a couple of directories like /bin, /etc, etc. u-root has a default internally supplied set of files; use base=/dev/null if you don't want any base files.")
useExistingInit = flag.Bool("useinit", false, "Use existing init from base archive (only if --base was specified).")
outputPath = flag.String("o", "", "Path to output initramfs file.")

initCmd = flag.String("initcmd", "init", "Symlink target for /init. Can be an absolute path or a u-root command name. Use initcmd=\"\" if you don't want the symlink.")
uinitCmd = flag.String("uinitcmd", "", "Symlink target and arguments for /bin/uinit. Can be an absolute path or a u-root command name. Use uinitcmd=\"\" if you don't want the symlink. E.g. -uinitcmd=\"echo foobar\"")
defaultShell = flag.String("defaultsh", sh, "Default shell. Can be an absolute path or a u-root command name. Use defaultsh=\"\" if you don't want the symlink.")

noCommands = flag.Bool("nocmd", false, "Build no Go commands; initramfs only")

flag.Var(&extraFiles, "files", "Additional files, directories, and binaries (with their ldd dependencies) to add to archive. Can be specified multiple times.")

shellbang = flag.Bool("shellbang", false, "Use #! instead of symlinks for busybox")

// Flag for the new filepath only mode. This will be required to find the u-root commands and make templates work
// In almost every case, "." is fine.
urootSourceDir = flag.String("uroot-source", ".", "Path to the locally checked out u-root source tree in case commands from there are desired.")
}

// checkArgs checks for common mistakes that cause confusion.
// 1. -files as the last argument
// 2. -files followed by any switch, indicating a shell expansion problem
Expand Down Expand Up @@ -123,41 +61,42 @@ func main() {
log.Fatal(err)
}

gbbOpts := &golang.BuildOpts{}
gbbOpts.RegisterFlags(flag.CommandLine)
// Register an alias for -go-no-strip for backwards compatibility.
flag.CommandLine.BoolVar(&gbbOpts.NoStrip, "no-strip", false, "Build unstripped binaries")
var sh string
if golang.Default().GOOS != "plan9" {
sh = "gosh"
}

env := golang.Default()
env.RegisterFlags(flag.CommandLine)
tags := (*uflag.Strings)(&env.BuildTags)
flag.CommandLine.Var(tags, "tags", "Go build tags -- repeat the flag for multiple values")
env := golang.Default(golang.DisableCGO())
f := &uflags.Flags{
Commands: uflags.CommandFlags{
Env: env,
Builder: "bb",
BuildOpts: &golang.BuildOpts{},
},
Init: "init",
Shell: sh,
ArchiveFormat: "cpio",
OutputFile: defaultFile(env),
}
f.RegisterFlags(flag.CommandLine)

l := llog.Default()
l.RegisterVerboseFlag(flag.CommandLine, "v", slog.LevelDebug)
flag.Parse()

if usrc := os.Getenv("UROOT_SOURCE"); usrc != "" && *urootSourceDir == "" {
*urootSourceDir = usrc
}

if env.CgoEnabled {
l.Infof("Disabling CGO for u-root...")
env.CgoEnabled = false
}
l.Infof("Build environment: %s", env)
if env.GOOS != "linux" {
l.Warnf("GOOS is not linux. Did you mean to set GOOS=linux?")
}

// Main is in a separate functions so defers run on return.
if err := Main(l, env, gbbOpts); err != nil {
if err := Main(l, f); err != nil {
l.Errorf("Build error: %v", err)
return
}

if stat, err := os.Stat(*outputPath); err == nil {
l.Infof("Successfully built %q (size %d bytes -- %s).", *outputPath, stat.Size(), humanize.IBytes(uint64(stat.Size())))
if stat, err := os.Stat(f.OutputFile); err == nil {
l.Infof("Successfully built %q (size %d bytes -- %s).", f.OutputFile, stat.Size(), humanize.IBytes(uint64(stat.Size())))
}
}

Expand All @@ -176,26 +115,6 @@ func isRecommendedVersion(v string) bool {
return false
}

func getReader(format string, path string) initramfs.ReadOpener {
switch format {
case "cpio":
return &initramfs.CPIOFile{Path: path}
default:
return nil
}
}

func getWriter(format string, path string) initramfs.WriteOpener {
switch format {
case "cpio":
return &initramfs.CPIOFile{Path: path}
case "dir":
return &initramfs.Dir{Path: path}
default:
return nil
}
}

func defaultFile(env *golang.Environ) string {
if len(env.GOOS) == 0 || len(env.GOARCH) == 0 {
return "/tmp/initramfs.cpio"
Expand All @@ -205,7 +124,8 @@ func defaultFile(env *golang.Environ) string {

// Main is a separate function so defers are run on return, which they wouldn't
// on exit.
func Main(l *llog.Logger, env *golang.Environ, buildOpts *golang.BuildOpts) error {
func Main(l *llog.Logger, f *uflags.Flags) error {
env := f.Commands.Env
v, err := env.Version()
if err != nil {
l.Infof("Could not get environment's Go version, using runtime's version: %v", err)
Expand All @@ -219,73 +139,32 @@ func Main(l *llog.Logger, env *golang.Environ, buildOpts *golang.BuildOpts) erro
v, recommendedVersions, recommendedVersions[0])
}

if *outputPath == "" && *format == "cpio" {
*outputPath = defaultFile(env)
}
output := getWriter(*format, *outputPath)

var base initramfs.ReadOpener
base = &initramfs.Archive{Archive: uimage.DefaultRamfs()}
if *basePath != "" {
base = getReader(*format, *basePath)
}

tempDir := *tmpDir
if tempDir == "" {
if f.TempDir == "" {
var err error
tempDir, err = os.MkdirTemp("", "u-root")
f.TempDir, err = os.MkdirTemp("", "u-root")
if err != nil {
return err
}
defer os.RemoveAll(tempDir)
} else if _, err := os.Stat(tempDir); os.IsNotExist(err) {
if err := os.MkdirAll(tempDir, 0o755); err != nil {
return fmt.Errorf("temporary directory %q did not exist; tried to mkdir but failed: %v", tempDir, err)
if f.KeepTempDir {
defer func() {
l.Infof("Keeping temp dir %s", f.TempDir)
}()
} else {
defer os.RemoveAll(f.TempDir)
}
}

var c []uimage.Commands
if !*noCommands {
var b builder.Builder
switch *build {
case "bb", "gbb":
b = builder.GBBBuilder{ShellBang: *shellbang}
case "binary":
b = builder.BinaryBuilder{}
default:
return fmt.Errorf("could not find builder %q", *build)
} else if _, err := os.Stat(f.TempDir); os.IsNotExist(err) {
if err := os.MkdirAll(f.TempDir, 0o755); err != nil {
return fmt.Errorf("temporary directory %q did not exist; tried to mkdir but failed: %v", f.TempDir, err)
}

pkgs := flag.Args()
if len(pkgs) == 0 {
pkgs = []string{"github.com/u-root/u-root/cmds/core/*"}
}

c = append(c, uimage.Commands{
Builder: b,
Packages: pkgs,
BuildOpts: buildOpts,
})
}

opts := uimage.Opts{
Env: env,
Commands: c,
UrootSource: *urootSourceDir,
TempDir: tempDir,
ExtraFiles: extraFiles,
OutputFile: output,
BaseArchive: base,
UseExistingInit: *useExistingInit,
InitCmd: *initCmd,
DefaultShell: *defaultShell,
// Set default output.
m := []uimage.Modifier{
uimage.WithCPIOOutput(defaultFile(env)),
}
uinitArgs := shlex.Split(*uinitCmd)
if len(uinitArgs) > 0 {
opts.UinitCmd = uinitArgs[0]
}
if len(uinitArgs) > 1 {
opts.UinitArgs = uinitArgs[1:]
more, err := f.Modifiers(flag.Args()...)
if err != nil {
return err
}
return uimage.CreateInitramfs(l, opts)
return uimage.Create(l, append(m, more...)...)
}
4 changes: 2 additions & 2 deletions uimage/builder/builder.go
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Original file line number Diff line number Diff line change
Expand Up @@ -16,10 +16,10 @@ import (

var (
// Busybox is a shared GBBBuilder instance.
Busybox = GBBBuilder{}
Busybox = &GBBBuilder{}

// Binary is a shared BinaryBuilder instance.
Binary = BinaryBuilder{}
Binary = &BinaryBuilder{}
)

// Possible build errors.
Expand Down
2 changes: 1 addition & 1 deletion uimage/builder/gbb.go
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Original file line number Diff line number Diff line change
Expand Up @@ -48,7 +48,7 @@ func (GBBBuilder) DefaultBinaryDir() string {
}

// Build is an implementation of Builder.Build for a busybox-like initramfs.
func (b GBBBuilder) Build(l *llog.Logger, af *initramfs.Files, opts Opts) error {
func (b *GBBBuilder) Build(l *llog.Logger, af *initramfs.Files, opts Opts) error {
// Build the busybox binary.
if len(opts.TempDir) == 0 {
return ErrTempDirMissing
Expand Down
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