uimage API: add arbitrary CPIO records

uimage/initramfs/archive.go

@@ -57,6 +57,9 @@ type Opts struct {
 	// If this is false, the "init" file in BaseArchive will be renamed
 	// "inito" (for init-original) in the output archive.
 	UseExistingInit bool
+
+	// Records are additional CPIO records to include in the initramfs.
+	Records []cpio.Record
 }
 
 // Write uses the given options to determine which files to write to the output
@@ -99,6 +102,12 @@ func Write(opts *Opts) error {
 		}
 	}
 
+	for _, r := range opts.Records {
+		if err := opts.Files.AddRecord(r); err != nil {
+			return err
+		}
+	}
+
 	out, err := opts.OutputFile.OpenWriter()
 	if err != nil {
 		return err

uimage/initramfs/files_test.go

@@ -636,6 +636,48 @@ func TestOptsWrite(t *testing.T) {
 				cpio.Trailer: cpio.TrailerRecord,
 			},
 		},
+		{
+			desc: "base archive with init and extra records conflict",
+			opts: &Opts{
+				Files: &Files{
+					Records: map[string]cpio.Record{
+						"init": cpio.StaticFile("init", "huh", 0o111),
+					},
+				},
+				BaseArchive: &Archive{Archive: archive(t,
+					cpio.StaticFile("init", "boo", 0o555),
+				)},
+				Records: []cpio.Record{
+					cpio.StaticFile("init", "huh", 0o111),
+				},
+				UseExistingInit: true,
+			},
+			errs: []error{os.ErrExist},
+			output: &cpio.Archive{
+				Files: make(map[string]cpio.Record),
+			},
+		},
+		{
+			desc: "extra records",
+			opts: &Opts{
+				Files: &Files{
+					Records: map[string]cpio.Record{
+						"init": cpio.StaticFile("init", "huh", 0o111),
+					},
+				},
+				Records: []cpio.Record{
+					cpio.StaticFile("etc/foo", "huh", 0o111),
+				},
+			},
+			output: &cpio.Archive{
+				Files: make(map[string]cpio.Record),
+			},
+			want: Records{
+				"init":       cpio.StaticFile("init", "boo", 0o555),
+				"etc/foo":    cpio.StaticFile("etc/foo", "huh", 0o111),
+				cpio.Trailer: cpio.TrailerRecord,
+			},
+		},
 	} {
 		t.Run(fmt.Sprintf("Test %02d (%s)", i, tt.desc), func(t *testing.T) {
 			tt.opts.OutputFile = &Archive{tt.output}

uimage/uimage.go

@@ -236,6 +236,9 @@ type Opts struct {
 	//
 	// This must be specified to have a default shell.
 	DefaultShell string
+
+	// Records are additional CPIO records to include in the initramfs.
+	Records []cpio.Record
 }
 
 // Modifier modifies uimage options.
@@ -503,6 +506,14 @@ func WithTempDir(dir string) Modifier {
 	}
 }
 
+// WithRecord adds CPIO records to include in the initramfs.
+func WithRecord(r ...cpio.Record) Modifier {
+	return func(o *Opts) error {
+		o.Records = append(o.Records, r...)
+		return nil
+	}
+}
+
 // Create creates an initramfs from mods specifications.
 func Create(l *llog.Logger, mods ...Modifier) error {
 	o, err := OptionsFor(mods...)
@@ -571,6 +582,7 @@ func CreateInitramfs(l *llog.Logger, opts Opts) error {
 		OutputFile:      opts.OutputFile,
 		BaseArchive:     opts.BaseArchive,
 		UseExistingInit: opts.UseExistingInit,
+		Records:         opts.Records,
 	}
 	if err := ParseExtraFiles(l, archive.Files, opts.ExtraFiles, !opts.SkipLDD); err != nil {
 		return err

uimage/uimage_test.go

@@ -505,6 +505,46 @@ func TestCreateInitramfs(t *testing.T) {
 				itest.IsEmpty{},
 			},
 		},
+		{
+			name: "extra records conflict",
+			opts: Opts{
+				Env:          golang.Default(golang.DisableCGO()),
+				TempDir:      dir,
+				InitCmd:      "init",
+				DefaultShell: "ls",
+				Records: []cpio.Record{
+					cpio.StaticFile("bbin/ls", "foo", 0o111),
+				},
+				Commands: BusyboxCmds(
+					"github.com/u-root/u-root/cmds/core/init",
+					"github.com/u-root/u-root/cmds/core/ls",
+				),
+			},
+			errs: []error{os.ErrExist},
+			validators: []itest.ArchiveValidator{
+				itest.IsEmpty{},
+			},
+		},
+		{
+			name: "extra records",
+			opts: Opts{
+				Env:          golang.Default(golang.DisableCGO()),
+				TempDir:      dir,
+				InitCmd:      "init",
+				DefaultShell: "ls",
+				Records: []cpio.Record{
+					cpio.StaticFile("etc/foo", "foo", 0o111),
+				},
+				Commands: BusyboxCmds(
+					"github.com/u-root/u-root/cmds/core/init",
+					"github.com/u-root/u-root/cmds/core/ls",
+				),
+			},
+			validators: []itest.ArchiveValidator{
+				itest.HasFile{Path: "bbin/bb"},
+				itest.HasRecord{R: cpio.StaticFile("etc/foo", "foo", 0o111)},
+			},
+		},
 	} {
 		t.Run(fmt.Sprintf("Test %d [%s]", i, tt.name), func(t *testing.T) {
 			archive := cpio.InMemArchive()
@@ -992,6 +1032,42 @@ func TestCreateInitramfsWithAPI(t *testing.T) {
 				itest.IsEmpty{},
 			},
 		},
+		{
+			name: "extra records conflict",
+			opts: []Modifier{
+				WithTempDir(dir),
+				WithEnv(golang.DisableCGO()),
+				WithInit("init"),
+				WithShell("ls"),
+				WithRecord(cpio.StaticFile("bbin/ls", "foo", 0o111)),
+				WithBusyboxCommands(
+					"github.com/u-root/u-root/cmds/core/init",
+					"github.com/u-root/u-root/cmds/core/ls",
+				),
+			},
+			errs: []error{os.ErrExist},
+			validators: []itest.ArchiveValidator{
+				itest.IsEmpty{},
+			},
+		},
+		{
+			name: "extra records",
+			opts: []Modifier{
+				WithTempDir(dir),
+				WithEnv(golang.DisableCGO()),
+				WithInit("init"),
+				WithShell("ls"),
+				WithRecord(cpio.StaticFile("etc/foo", "foo", 0o111)),
+				WithBusyboxCommands(
+					"github.com/u-root/u-root/cmds/core/init",
+					"github.com/u-root/u-root/cmds/core/ls",
+				),
+			},
+			validators: []itest.ArchiveValidator{
+				itest.HasFile{Path: "bbin/bb"},
+				itest.HasRecord{R: cpio.StaticFile("etc/foo", "foo", 0o111)},
+			},
+		},
 	} {
 		t.Run(fmt.Sprintf("Test %d [%s]", i, tt.name), func(t *testing.T) {
 			archive := cpio.InMemArchive()