pkg: write tar status

This serves as a status indicator while fetching large tarballs, and
preserves information otherwise stripped during unpacking. This is a
revision of the tarArtifact to avoid inconsistent state from previously
cured tarArtifact lacking their status files.

Signed-off-by: Ophestra <cat@gensokyo.uk>

3 files changed, 97 insertions, 15 deletions

diff --git a/pkg/pkg_test.go b/pkg/pkg_test.go
index aa5016c1..775b68d9 100644
--- a/pkg/pkg_test.go
+++ b/pkg/pkg_test.go
@@ -587,7 +587,9 @@ func checkWithCache(t *testing.T, testCases []cacheTestCase) {
 
 			// destroy empty fault directory
 			if err := os.Remove(base.Append("fault").String()); err != nil {
-				t.Fatal(err)
+				if !errors.Is(err, syscall.ENOTEMPTY) {
+					t.Fatal(err)
+				}
 			}
 
 			want := tc.want.hash()
diff --git a/pkg/tar.go b/pkg/tar.go
index 9a8c4b76..33952b05 100644
--- a/pkg/tar.go
+++ b/pkg/tar.go
@@ -66,6 +66,9 @@ func (a *tarArtifact) Inputs() []Artifact {
 // IsExclusive returns false: decompressor and tar reader are fully sequential.
 func (a *tarArtifact) IsExclusive() bool { return false }
 
+// Revision satisfies [RevisionArtifact] for status behaviour.
+func (*tarArtifact) Revision() uint64 { return 0 }
+
 // A DisallowedTypeflagError describes a disallowed typeflag encountered while
 // unpacking a tarball.
 type DisallowedTypeflagError byte
@@ -76,6 +79,11 @@ func (e DisallowedTypeflagError) Error() string {
 
 // Cure cures the [Artifact], producing a directory located at work.
 func (a *tarArtifact) Cure(t *TContext) (err error) {
+	var status io.Writer
+	if status, err = t.GetStatusWriter(); err != nil {
+		return
+	}
+
 	var r io.ReadCloser
 	if r, err = t.Open(a.f); err != nil {
 		return
@@ -110,6 +118,7 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 
 	var header *tar.Header
 	tr := tar.NewReader(r)
+	msg := t.GetMessage()
 	for header, err = tr.Next(); err == nil; header, err = tr.Next() {
 		typeflag := header.Typeflag
 		if typeflag == 0 {
@@ -126,6 +135,7 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 			}
 		}
 
+		var m string
 		switch typeflag {
 		case tar.TypeReg:
 			var f *os.File
@@ -142,6 +152,13 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 			} else if err = f.Close(); err != nil {
 				return
 			}
+
+			m = fmt.Sprintf(
+				"%s %s (%d bytes)",
+				header.FileInfo().Mode(),
+				header.Name,
+				header.Size,
+			)
 			break
 
 		case tar.TypeLink:
@@ -151,6 +168,13 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 			); err != nil {
 				return
 			}
+
+			m = fmt.Sprintf(
+				"%s %s linkname %s",
+				header.FileInfo().Mode(),
+				header.Name,
+				header.Linkname,
+			)
 			break
 
 		case tar.TypeSymlink:
@@ -160,6 +184,13 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 			); err != nil {
 				return
 			}
+
+			m = fmt.Sprintf(
+				"%s %s linkname %s",
+				header.FileInfo().Mode(),
+				header.Name,
+				header.Linkname,
+			)
 			break
 
 		case tar.TypeDir:
@@ -170,21 +201,37 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 			if err = root.MkdirAll(header.Name, 0700); err != nil {
 				return
 			}
+
+			m = fmt.Sprintf(
+				"%s %s",
+				header.FileInfo().Mode(),
+				header.Name,
+			)
 			break
 
 		case tar.TypeChar:
-			t.GetMessage().Verbosef(
-				"%sskipping character device %d, %d %q%s",
-				t.cache.sgrWarn, header.Devmajor, header.Devminor, header.Name, t.cache.sgrRes,
+			m = fmt.Sprintf(
+				"skipping character device %d, %d %q",
+				header.Devmajor, header.Devminor, header.Name,
 			)
-			continue
+			break
 
 		case tar.TypeXGlobalHeader:
-			continue // ignore
+			m = "skipping PAX global key-value record"
+			break
 
 		default:
 			return DisallowedTypeflagError(typeflag)
 		}
+
+		if m != "" {
+			msg.Verbose(m)
+			if _, err = io.WriteString(status, m); err != nil {
+				return
+			} else if _, err = status.Write([]byte{'\n'}); err != nil {
+				return
+			}
+		}
 	}
 	if errors.Is(err, io.EOF) {
 		err = nil
diff --git a/pkg/tar_test.go b/pkg/tar_test.go
index 5462714f..28fec2d2 100644
--- a/pkg/tar_test.go
+++ b/pkg/tar_test.go
@@ -44,6 +44,24 @@ func TestTar(t *testing.T) {
 	}
 	wantExpandEncode := pkg.Encode(wantExpand.hash())
 
+	const (
+		wantStatus = `drwx------ checksum/
+drwx------ checksum/1TL00Qb8dcqayX7wTO8WNaraHvY6b-KCsctLDTrb64QBCmxj_-byK1HdIUwMaFEP/
+-r-------- checksum/1TL00Qb8dcqayX7wTO8WNaraHvY6b-KCsctLDTrb64QBCmxj_-byK1HdIUwMaFEP/check (2 bytes)
+drwx------ checksum/1TL00Qb8dcqayX7wTO8WNaraHvY6b-KCsctLDTrb64QBCmxj_-byK1HdIUwMaFEP/lib/
+Lrwxrwxrwx checksum/1TL00Qb8dcqayX7wTO8WNaraHvY6b-KCsctLDTrb64QBCmxj_-byK1HdIUwMaFEP/lib/libedac.so linkname /proc/nonexistent/libedac.so
+drwx------ checksum/1TL00Qb8dcqayX7wTO8WNaraHvY6b-KCsctLDTrb64QBCmxj_-byK1HdIUwMaFEP/lib/pkgconfig/
+drwx------ identifier/
+Lrwxrwxrwx identifier/HnySzeLQvSBZuTUcvfmLEX_OmH4yJWWH788NxuLuv7kVn8_uPM6Ks4rqFWM2NZJY linkname ../checksum/1TL00Qb8dcqayX7wTO8WNaraHvY6b-KCsctLDTrb64QBCmxj_-byK1HdIUwMaFEP
+Lrwxrwxrwx identifier/Zx5ZG9BAwegNT3zQwCySuI2ktCXxNgxirkGLFjW4FW06PtojYVaCdtEw8yuntPLa linkname ../checksum/1TL00Qb8dcqayX7wTO8WNaraHvY6b-KCsctLDTrb64QBCmxj_-byK1HdIUwMaFEP
+drwx------ work/
+`
+
+		wantStatusExpand = `drwx------ lib/
+Lrwxrwxrwx lib/libedac.so linkname /proc/nonexistent/libedac.so
+`
+	)
+
 	checkWithCache(t, []cacheTestCase{
 		{"http", 0, nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			checkTarHTTP(t, base, c, fstest.MapFS{
@@ -79,8 +97,12 @@ func TestTar(t *testing.T) {
 			"checksum/" + wantEncode + "/work": {Mode: fs.ModeDir | 0500},
 
 			"identifier": {Mode: fs.ModeDir | 0700},
-			"identifier/snWp53xxNdx6cV5KSJqzyVWzLlTsFd8udOisIu8Rgxly09mGcxufYCoQ5CQrHDyZ": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/" + wantEncode)},
-			"identifier/v9DUj2R4YK_3ae0m9VuUYI-HJysDDCENu1k10thxioycRzFH1Qejw5bBGukm4IdL": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/" + wantEncode)},
+			"identifier/82-Dwiovp_DGXPBmnmrTk4XtsduvTBBXxnJTBgyp6avsUhjcqmL9yKQLxkwJJM0x": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/" + wantEncode)},
+			"identifier/ld6DxwiP2Gj47Ue2L_pFv6NrOth8nkU5W1voMyivd2aVROrorGqPlpbyHUnU1AvI": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/" + wantEncode)},
+
+			"status": {Mode: fs.ModeDir | 0700},
+			"status/82-Dwiovp_DGXPBmnmrTk4XtsduvTBBXxnJTBgyp6avsUhjcqmL9yKQLxkwJJM0x": {Mode: 0400, Data: []byte(statusHeader + wantStatus)},
+			"status/ld6DxwiP2Gj47Ue2L_pFv6NrOth8nkU5W1voMyivd2aVROrorGqPlpbyHUnU1AvI": {Mode: 0400, Data: []byte(statusHeader + wantStatus)},
 
 			"substitute": {Mode: fs.ModeDir | 0700},
 
@@ -103,8 +125,12 @@ func TestTar(t *testing.T) {
 			"checksum/" + wantExpandEncode + "/libedac.so": {Mode: fs.ModeSymlink | 0777, Data: []byte("/proc/nonexistent/libedac.so")},
 
 			"identifier": {Mode: fs.ModeDir | 0700},
-			"identifier/1SuvgGltcsgqps9tWqjULG8RCdpx_6KVWXdsMd5xPKvdtysOxqpE-3bLu4j0WpGk": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/" + wantExpandEncode)},
-			"identifier/snWp53xxNdx6cV5KSJqzyVWzLlTsFd8udOisIu8Rgxly09mGcxufYCoQ5CQrHDyZ": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/" + wantExpandEncode)},
+			"identifier/82-Dwiovp_DGXPBmnmrTk4XtsduvTBBXxnJTBgyp6avsUhjcqmL9yKQLxkwJJM0x": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/" + wantExpandEncode)},
+			"identifier/fsMFOV4_LoYWbC8GNqL2zjbpzNzT80vPWbSw4L47caKVIta333WIW2TZXoSW8ntH": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/" + wantExpandEncode)},
+
+			"status": {Mode: fs.ModeDir | 0700},
+			"status/82-Dwiovp_DGXPBmnmrTk4XtsduvTBBXxnJTBgyp6avsUhjcqmL9yKQLxkwJJM0x": {Mode: 0400, Data: []byte(statusHeader + wantStatusExpand)},
+			"status/fsMFOV4_LoYWbC8GNqL2zjbpzNzT80vPWbSw4L47caKVIta333WIW2TZXoSW8ntH": {Mode: 0400, Data: []byte(statusHeader + wantStatusExpand)},
 
 			"substitute": {Mode: fs.ModeDir | 0700},
 
@@ -206,13 +232,13 @@ func checkTarHTTP(
 
 		{"directory", pkg.NewTar(&tarDir), ignorePathname, want, pkg.WNew, nil},
 
-		{"multiple entries", pkg.NewTar(&tarDirMulti), nil, nil, pkg.WNew, errors.New(
+		{"multiple entries", pkg.NewTar(&tarDirMulti), nil, nil, pkg.WNew, errors.Join(errors.New(
 			"input directory does not contain a single regular file",
-		)},
+		))},
 
-		{"bad type", pkg.NewTar(&tarDirType), nil, nil, pkg.WNew, errors.New(
+		{"bad type", pkg.NewTar(&tarDirType), nil, nil, pkg.WNew, errors.Join(errors.New(
 			"input directory does not contain a single regular file",
-		)},
+		))},
 
 		{"error passthrough", pkg.NewTar(&stubArtifact{
 			kind:   pkg.KindExec,
@@ -220,6 +246,13 @@ func checkTarHTTP(
 			cure: func(t *pkg.TContext) error {
 				return stub.UniqueError(0xcafe)
 			},
-		}), nil, nil, pkg.WNew, stub.UniqueError(0xcafe)},
+		}), nil, nil, pkg.WNew, errors.Join(stub.UniqueError(0xcafe))},
 	})
+
+	fault := base.Append("fault")
+	if err := os.RemoveAll(fault.String()); err != nil {
+		t.Fatal(err)
+	} else if err = os.Mkdir(fault.String(), 0); err != nil {
+		t.Fatal(err)
+	}
 }