ldd: decode from reader

This should reduce memory footprint of the parsing process and allow decoding part of the stream.

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

ldd/error.go

@@ -1,27 +0,0 @@
-package ldd
-
-import (
-	"errors"
-	"fmt"
-)
-
-var (
-	ErrUnexpectedSeparator = errors.New("unexpected separator")
-	ErrPathNotAbsolute     = errors.New("path not absolute")
-	ErrBadLocationFormat   = errors.New("bad location format")
-	ErrUnexpectedNewline   = errors.New("unexpected newline")
-)
-
-type EntryUnexpectedSegmentsError string
-
-func (e EntryUnexpectedSegmentsError) Is(err error) bool {
-	var eq EntryUnexpectedSegmentsError
-	if !errors.As(err, &eq) {
-		return false
-	}
-	return e == eq
-}
-
-func (e EntryUnexpectedSegmentsError) Error() string {
-	return fmt.Sprintf("unexpected segments in entry %q", string(e))
-}

ldd/exec.go

@@ -3,6 +3,7 @@ package ldd
 import (
 	"bytes"
 	"context"
+	"errors"
 	"io"
 	"os"
 	"os/exec"
@@ -16,11 +17,14 @@ import (
 	"hakurei.app/message"
 )
 
-var (
-	msgStatic      = []byte("Not a valid dynamic program")
-	msgStaticGlibc = []byte("not a dynamic executable")
+const (
+	// msgStaticSuffix is the suffix of message printed to stderr by musl on a statically linked program.
+	msgStaticSuffix = ": Not a valid dynamic program"
+	// msgStaticGlibc is a substring of the message printed to stderr by glibc on a statically linked program.
+	msgStaticGlibc = "not a dynamic executable"
 )
 
+// Exec runs ldd(1) in a restrictive [container] and connects it to a [Decoder], returning resulting entries.
 func Exec(ctx context.Context, msg message.Msg, p string) ([]*Entry, error) {
 	const (
 		lddName    = "ldd"
@@ -41,14 +45,20 @@ func Exec(ctx context.Context, msg message.Msg, p string) ([]*Entry, error) {
 	z.Hostname = "hakurei-" + lddName
 	z.SeccompFlags |= seccomp.AllowMultiarch
 	z.SeccompPresets |= std.PresetStrict
-	stdout, stderr := new(bytes.Buffer), new(bytes.Buffer)
-	z.Stdout = stdout
+	stderr := new(bytes.Buffer)
 	z.Stderr = stderr
 	z.
 		Bind(fhs.AbsRoot, fhs.AbsRoot, 0).
 		Proc(fhs.AbsProc).
 		Dev(fhs.AbsDev, false)
 
+	var d *Decoder
+	if r, err := z.StdoutPipe(); err != nil {
+		return nil, err
+	} else {
+		d = NewDecoder(r)
+	}
+
 	if err := z.Start(); err != nil {
 		return nil, err
 	}
@@ -56,15 +66,18 @@ func Exec(ctx context.Context, msg message.Msg, p string) ([]*Entry, error) {
 	if err := z.Serve(); err != nil {
 		return nil, err
 	}
+
+	entries, decodeErr := d.Decode()
 	if err := z.Wait(); err != nil {
 		m := stderr.Bytes()
-		if bytes.Contains(m, append([]byte(p+": "), msgStatic...)) ||
-			bytes.Contains(m, msgStaticGlibc) {
+		if bytes.Contains(m, []byte(msgStaticSuffix)) || bytes.Contains(m, []byte(msgStaticGlibc)) {
 			return nil, nil
 		}
+
+		if decodeErr != nil {
+			return nil, errors.Join(decodeErr, err)
+		}
 		return nil, err
 	}
-
-	v := stdout.Bytes()
-	return Parse(v)
+	return entries, decodeErr
 }

ldd/ldd.go

@@ -2,65 +2,203 @@
 package ldd
 
 import (
-	"math"
-	"path"
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
 	"strconv"
-	"strings"
+
+	"hakurei.app/container/check"
 )
 
+var (
+	// ErrUnexpectedNewline is returned when encountering an unexpected empty line.
+	ErrUnexpectedNewline = errors.New("unexpected newline")
+	// ErrUnexpectedSeparator is returned when encountering an unexpected separator segment.
+	ErrUnexpectedSeparator = errors.New("unexpected separator")
+	// ErrBadLocationFormat is returned for an incorrectly formatted [Entry.Location] segment.
+	ErrBadLocationFormat = errors.New("bad location format")
+)
+
+// EntryUnexpectedSegmentsError is returned when encountering
+// a line containing unexpected number of segments.
+type EntryUnexpectedSegmentsError string
+
+func (e EntryUnexpectedSegmentsError) Error() string {
+	return fmt.Sprintf("unexpected segments in entry %q", string(e))
+}
+
+// An Entry represents one line of ldd(1) output.
 type Entry struct {
-	Name     string `json:"name,omitempty"`
-	Path     string `json:"path,omitempty"`
+	// File name of required object.
+	Name string `json:"name"`
+	// Absolute pathname of matched object. Only populated for the long variant.
+	Path *check.Absolute `json:"path,omitempty"`
+	// Address at which the object is loaded.
 	Location uint64 `json:"location"`
 }
 
-func Parse(p []byte) ([]*Entry, error) {
-	payload := strings.Split(strings.TrimSpace(string(p)), "\n")
-	result := make([]*Entry, len(payload))
-
-	for i, ent := range payload {
-		if len(ent) == 0 {
-			return nil, ErrUnexpectedNewline
+// Path returns a deduplicated slice of absolute directory paths in entries.
+func Path(entries []*Entry) []*check.Absolute {
+	p := make([]*check.Absolute, 0, len(entries)*2)
+	for _, entry := range entries {
+		if entry.Path != nil {
+			p = append(p, entry.Path.Dir())
 		}
-
-		segment := strings.SplitN(ent, " ", 5)
-
-		// location index
-		var iL int
-
-		switch len(segment) {
-		case 2: // /lib/ld-musl-x86_64.so.1 (0x7f04d14ef000)
-			iL = 1
-			result[i] = &Entry{Name: strings.TrimSpace(segment[0])}
-		case 4: // libc.musl-x86_64.so.1 => /lib/ld-musl-x86_64.so.1 (0x7f04d14ef000)
-			iL = 3
-			if segment[1] != "=>" {
-				return nil, ErrUnexpectedSeparator
-			}
-			if !path.IsAbs(segment[2]) {
-				return nil, ErrPathNotAbsolute
-			}
-			result[i] = &Entry{
-				Name: strings.TrimSpace(segment[0]),
-				Path: segment[2],
-			}
-		default:
-			return nil, EntryUnexpectedSegmentsError(ent)
+		if a, err := check.NewAbs(entry.Name); err == nil {
+			p = append(p, a.Dir())
 		}
+	}
+	check.SortAbs(p)
+	return check.CompactAbs(p)
+}
 
-		if loc, err := parseLocation(segment[iL]); err != nil {
-			return nil, err
+const (
+	// entrySegmentIndexName is the index of the segment holding [Entry.Name].
+	entrySegmentIndexName = 0
+	// entrySegmentIndexPath is the index of the segment holding [Entry.Path],
+	// present only for a line describing a fully populated [Entry].
+	entrySegmentIndexPath = 2
+	// entrySegmentIndexSeparator is the index of the segment containing the magic bytes entrySegmentFullSeparator,
+	// present only for a line describing a fully populated [Entry].
+	entrySegmentIndexSeparator = 1
+	// entrySegmentIndexLocation is the index of the segment holding [Entry.Location]
+	// for a line describing a fully populated [Entry].
+	entrySegmentIndexLocation = 3
+	// entrySegmentIndexLocationShort is the index of the segment holding [Entry.Location]
+	// for a line describing only [Entry.Name].
+	entrySegmentIndexLocationShort = 1
+
+	// entrySegmentSep is the byte separating segments in an [Entry] line.
+	entrySegmentSep = ' '
+	// entrySegmentFullSeparator is the exact contents of the segment at index entrySegmentIndexSeparator.
+	entrySegmentFullSeparator = "=>"
+
+	// entrySegmentLocationLengthMin is the minimum possible length of a segment corresponding to [Entry.Location].
+	entrySegmentLocationLengthMin = 4
+	// entrySegmentLocationPrefix are magic bytes prefixing a segment corresponding to [Entry.Location].
+	entrySegmentLocationPrefix = "(0x"
+	// entrySegmentLocationSuffix is the magic byte suffixing a segment corresponding to [Entry.Location].
+	entrySegmentLocationSuffix = ')'
+)
+
+// decodeLocationSegment decodes and saves the segment corresponding to [Entry.Location].
+func (e *Entry) decodeLocationSegment(segment []byte) (err error) {
+	if len(segment) < entrySegmentLocationLengthMin ||
+		segment[len(segment)-1] != entrySegmentLocationSuffix ||
+		string(segment[:len(entrySegmentLocationPrefix)]) != entrySegmentLocationPrefix {
+		return ErrBadLocationFormat
+	}
+
+	e.Location, err = strconv.ParseUint(string(segment[3:len(segment)-1]), 16, 64)
+	return
+}
+
+// UnmarshalText parses a line of ldd(1) output and saves it to [Entry].
+func (e *Entry) UnmarshalText(data []byte) error {
+	var (
+		segments = bytes.SplitN(data, []byte{entrySegmentSep}, 5)
+		// segment to pass to decodeLocationSegment
+		iL int
+	)
+
+	switch len(segments) {
+	case 2: // /lib/ld-musl-x86_64.so.1 (0x7f04d14ef000)
+		iL = entrySegmentIndexLocationShort
+		e.Name = string(bytes.TrimSpace(segments[entrySegmentIndexName]))
+
+	case 4: // libc.musl-x86_64.so.1 => /lib/ld-musl-x86_64.so.1 (0x7f04d14ef000)
+		iL = entrySegmentIndexLocation
+		if string(segments[entrySegmentIndexSeparator]) != entrySegmentFullSeparator {
+			return ErrUnexpectedSeparator
+		}
+		if a, err := check.NewAbs(string(segments[entrySegmentIndexPath])); err != nil {
+			return err
 		} else {
-			result[i].Location = loc
+			e.Path = a
 		}
+		e.Name = string(bytes.TrimSpace(segments[entrySegmentIndexName]))
+
+	default:
+		return EntryUnexpectedSegmentsError(data)
 	}
 
-	return result, nil
+	return e.decodeLocationSegment(segments[iL])
 }
 
-func parseLocation(s string) (uint64, error) {
-	if len(s) < 4 || s[len(s)-1] != ')' || s[:3] != "(0x" {
-		return math.MaxUint64, ErrBadLocationFormat
-	}
-	return strconv.ParseUint(s[3:len(s)-1], 16, 64)
+// A Decoder reads and decodes [Entry] values from an input stream.
+//
+// The zero value is not safe for use.
+type Decoder struct {
+	s *bufio.Scanner
+
+	// Whether the current line is not the first line.
+	notFirst bool
+	// Whether s has no more tokens.
+	depleted bool
+	// Holds onto the first error encountered while parsing.
+	err error
 }
+
+// NewDecoder returns a new decoder that reads from r.
+//
+// The decoder introduces its own buffering and may read
+// data from r beyond the [Entry] values requested.
+func NewDecoder(r io.Reader) *Decoder { return &Decoder{s: bufio.NewScanner(r)} }
+
+// Scan advances the [Decoder] to the next [Entry] and
+// stores the result in the value pointed to by v.
+func (d *Decoder) Scan(v *Entry) bool {
+	if d.s == nil || d.err != nil || d.depleted {
+		return false
+	}
+	if !d.s.Scan() {
+		d.depleted = true
+		return false
+	}
+
+	data := d.s.Bytes()
+	if len(data) == 0 {
+		if d.notFirst {
+			if d.s.Scan() && d.err == nil {
+				d.err = ErrUnexpectedNewline
+			}
+			// trailing newline is allowed (glibc)
+			return false
+		}
+
+		// leading newline is allowed (musl)
+		d.notFirst = true
+		return d.Scan(v)
+	}
+
+	d.notFirst = true
+	d.err = v.UnmarshalText(data)
+	return d.err == nil
+}
+
+// Err returns the first non-EOF error that was encountered
+// by the underlying [bufio.Scanner] or [Entry].
+func (d *Decoder) Err() error {
+	if d.err != nil || d.s == nil {
+		return d.err
+	}
+	return d.s.Err()
+}
+
+// Decode reads from the input stream until there are no more entries
+// and returns the results in a slice.
+func (d *Decoder) Decode() ([]*Entry, error) {
+	var entries []*Entry
+
+	e := new(Entry)
+	for d.Scan(e) {
+		entries = append(entries, e)
+		e = new(Entry)
+	}
+	return entries, d.Err()
+}
+
+// Parse returns a slice of addresses to [Entry] decoded from p.
+func Parse(p []byte) ([]*Entry, error) { return NewDecoder(bytes.NewReader(p)).Decode() }

ldd/ldd_test.go

@@ -1,10 +1,12 @@
 package ldd_test
 
 import (
+	"encoding/json"
 	"errors"
 	"reflect"
 	"testing"
 
+	"hakurei.app/container/check"
 	"hakurei.app/ldd"
 )
 
@@ -20,15 +22,19 @@ func TestParseError(t *testing.T) {
 
 libzstd.so.1 => /usr/lib/libzstd.so.1 (0x7ff71bfd2000)
 `, ldd.ErrUnexpectedNewline},
+
 		{"unexpected separator", `
 libzstd.so.1 = /usr/lib/libzstd.so.1 (0x7ff71bfd2000)
 `, ldd.ErrUnexpectedSeparator},
+
 		{"path not absolute", `
 libzstd.so.1 => usr/lib/libzstd.so.1 (0x7ff71bfd2000)
-`, ldd.ErrPathNotAbsolute},
+`, &check.AbsoluteError{Pathname: "usr/lib/libzstd.so.1"}},
+
 		{"unexpected segments", `
 meow libzstd.so.1 => /usr/lib/libzstd.so.1 (0x7ff71bfd2000)
 `, ldd.EntryUnexpectedSegmentsError("meow libzstd.so.1 => /usr/lib/libzstd.so.1 (0x7ff71bfd2000)")},
+
 		{"bad location format", `
 libzstd.so.1 => /usr/lib/libzstd.so.1 7ff71bfd2000
 `, ldd.ErrBadLocationFormat},
@@ -49,6 +55,7 @@ func TestParse(t *testing.T) {
 	testCases := []struct {
 		file, out string
 		want      []*ldd.Entry
+		paths     []*check.Absolute
 	}{
 		{"musl /bin/kmod", `
 /lib/ld-musl-x86_64.so.1 (0x7ff71c0a4000)
@@ -56,30 +63,38 @@ libzstd.so.1 => /usr/lib/libzstd.so.1 (0x7ff71bfd2000)
 liblzma.so.5 => /usr/lib/liblzma.so.5 (0x7ff71bf9a000)
 libz.so.1 => /lib/libz.so.1 (0x7ff71bf80000)
 libcrypto.so.3 => /lib/libcrypto.so.3 (0x7ff71ba00000)
-libc.musl-x86_64.so.1 => /lib/ld-musl-x86_64.so.1 (0x7ff71c0a4000)`,
-			[]*ldd.Entry{
-				{"/lib/ld-musl-x86_64.so.1", "", 0x7ff71c0a4000},
-				{"libzstd.so.1", "/usr/lib/libzstd.so.1", 0x7ff71bfd2000},
-				{"liblzma.so.5", "/usr/lib/liblzma.so.5", 0x7ff71bf9a000},
-				{"libz.so.1", "/lib/libz.so.1", 0x7ff71bf80000},
-				{"libcrypto.so.3", "/lib/libcrypto.so.3", 0x7ff71ba00000},
-				{"libc.musl-x86_64.so.1", "/lib/ld-musl-x86_64.so.1", 0x7ff71c0a4000},
-			}},
+libc.musl-x86_64.so.1 => /lib/ld-musl-x86_64.so.1 (0x7ff71c0a4000)`, []*ldd.Entry{
+			{"/lib/ld-musl-x86_64.so.1", nil, 0x7ff71c0a4000},
+			{"libzstd.so.1", check.MustAbs("/usr/lib/libzstd.so.1"), 0x7ff71bfd2000},
+			{"liblzma.so.5", check.MustAbs("/usr/lib/liblzma.so.5"), 0x7ff71bf9a000},
+			{"libz.so.1", check.MustAbs("/lib/libz.so.1"), 0x7ff71bf80000},
+			{"libcrypto.so.3", check.MustAbs("/lib/libcrypto.so.3"), 0x7ff71ba00000},
+			{"libc.musl-x86_64.so.1", check.MustAbs("/lib/ld-musl-x86_64.so.1"), 0x7ff71c0a4000},
+		}, []*check.Absolute{
+			check.MustAbs("/lib"),
+			check.MustAbs("/usr/lib"),
+		}},
+
 		{"glibc /nix/store/rc3n2r3nffpib2gqpxlkjx36frw6n34z-kmod-31/bin/kmod", `
 	linux-vdso.so.1 (0x00007ffed65be000)
 	libzstd.so.1 => /nix/store/80pxmvb9q43kh9rkjagc4h41vf6dh1y6-zstd-1.5.6/lib/libzstd.so.1 (0x00007f3199cd1000)
 	liblzma.so.5 => /nix/store/g78jna1i5qhh8gqs4mr64648f0szqgw4-xz-5.4.7/lib/liblzma.so.5 (0x00007f3199ca2000)
 	libc.so.6 => /nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib/libc.so.6 (0x00007f3199ab5000)
 	libpthread.so.0 => /nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib/libpthread.so.0 (0x00007f3199ab0000)
-	/nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib/ld-linux-x86-64.so.2 => /nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib64/ld-linux-x86-64.so.2 (0x00007f3199da5000)`,
-			[]*ldd.Entry{
-				{"linux-vdso.so.1", "", 0x00007ffed65be000},
-				{"libzstd.so.1", "/nix/store/80pxmvb9q43kh9rkjagc4h41vf6dh1y6-zstd-1.5.6/lib/libzstd.so.1", 0x00007f3199cd1000},
-				{"liblzma.so.5", "/nix/store/g78jna1i5qhh8gqs4mr64648f0szqgw4-xz-5.4.7/lib/liblzma.so.5", 0x00007f3199ca2000},
-				{"libc.so.6", "/nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib/libc.so.6", 0x00007f3199ab5000},
-				{"libpthread.so.0", "/nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib/libpthread.so.0", 0x00007f3199ab0000},
-				{"/nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib/ld-linux-x86-64.so.2", "/nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib64/ld-linux-x86-64.so.2", 0x00007f3199da5000},
-			}},
+	/nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib/ld-linux-x86-64.so.2 => /nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib64/ld-linux-x86-64.so.2 (0x00007f3199da5000)`, []*ldd.Entry{
+			{"linux-vdso.so.1", nil, 0x00007ffed65be000},
+			{"libzstd.so.1", check.MustAbs("/nix/store/80pxmvb9q43kh9rkjagc4h41vf6dh1y6-zstd-1.5.6/lib/libzstd.so.1"), 0x00007f3199cd1000},
+			{"liblzma.so.5", check.MustAbs("/nix/store/g78jna1i5qhh8gqs4mr64648f0szqgw4-xz-5.4.7/lib/liblzma.so.5"), 0x00007f3199ca2000},
+			{"libc.so.6", check.MustAbs("/nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib/libc.so.6"), 0x00007f3199ab5000},
+			{"libpthread.so.0", check.MustAbs("/nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib/libpthread.so.0"), 0x00007f3199ab0000},
+			{"/nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib/ld-linux-x86-64.so.2", check.MustAbs("/nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib64/ld-linux-x86-64.so.2"), 0x00007f3199da5000},
+		}, []*check.Absolute{
+			check.MustAbs("/nix/store/80pxmvb9q43kh9rkjagc4h41vf6dh1y6-zstd-1.5.6/lib"),
+			check.MustAbs("/nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib"),
+			check.MustAbs("/nix/store/c10zhkbp6jmyh0xc5kd123ga8yy2p4hk-glibc-2.39-52/lib64"),
+			check.MustAbs("/nix/store/g78jna1i5qhh8gqs4mr64648f0szqgw4-xz-5.4.7/lib"),
+		}},
+
 		{"glibc /usr/bin/xdg-dbus-proxy", `
 	linux-vdso.so.1 (0x00007725f5772000)
 	libglib-2.0.so.0 => /usr/lib/libglib-2.0.so.0 (0x00007725f55d5000)
@@ -93,31 +108,46 @@ libc.musl-x86_64.so.1 => /lib/ld-musl-x86_64.so.1 (0x7ff71c0a4000)`,
 	libmount.so.1 => /usr/lib/libmount.so.1 (0x00007725f5076000)
 	libffi.so.8 => /usr/lib/libffi.so.8 (0x00007725f506b000)
 	/lib64/ld-linux-x86-64.so.2 => /usr/lib64/ld-linux-x86-64.so.2 (0x00007725f5774000)
-	libblkid.so.1 => /usr/lib/libblkid.so.1 (0x00007725f5032000)`,
-			[]*ldd.Entry{
-				{"linux-vdso.so.1", "", 0x00007725f5772000},
-				{"libglib-2.0.so.0", "/usr/lib/libglib-2.0.so.0", 0x00007725f55d5000},
-				{"libgio-2.0.so.0", "/usr/lib/libgio-2.0.so.0", 0x00007725f5406000},
-				{"libgobject-2.0.so.0", "/usr/lib/libgobject-2.0.so.0", 0x00007725f53a6000},
-				{"libgcc_s.so.1", "/usr/lib/libgcc_s.so.1", 0x00007725f5378000},
-				{"libc.so.6", "/usr/lib/libc.so.6", 0x00007725f5187000},
-				{"libpcre2-8.so.0", "/usr/lib/libpcre2-8.so.0", 0x00007725f50e8000},
-				{"libgmodule-2.0.so.0", "/usr/lib/libgmodule-2.0.so.0", 0x00007725f50df000},
-				{"libz.so.1", "/usr/lib/libz.so.1", 0x00007725f50c6000},
-				{"libmount.so.1", "/usr/lib/libmount.so.1", 0x00007725f5076000},
-				{"libffi.so.8", "/usr/lib/libffi.so.8", 0x00007725f506b000},
-				{"/lib64/ld-linux-x86-64.so.2", "/usr/lib64/ld-linux-x86-64.so.2", 0x00007725f5774000},
-				{"libblkid.so.1", "/usr/lib/libblkid.so.1", 0x00007725f5032000},
-			}},
+	libblkid.so.1 => /usr/lib/libblkid.so.1 (0x00007725f5032000)`, []*ldd.Entry{
+			{"linux-vdso.so.1", nil, 0x00007725f5772000},
+			{"libglib-2.0.so.0", check.MustAbs("/usr/lib/libglib-2.0.so.0"), 0x00007725f55d5000},
+			{"libgio-2.0.so.0", check.MustAbs("/usr/lib/libgio-2.0.so.0"), 0x00007725f5406000},
+			{"libgobject-2.0.so.0", check.MustAbs("/usr/lib/libgobject-2.0.so.0"), 0x00007725f53a6000},
+			{"libgcc_s.so.1", check.MustAbs("/usr/lib/libgcc_s.so.1"), 0x00007725f5378000},
+			{"libc.so.6", check.MustAbs("/usr/lib/libc.so.6"), 0x00007725f5187000},
+			{"libpcre2-8.so.0", check.MustAbs("/usr/lib/libpcre2-8.so.0"), 0x00007725f50e8000},
+			{"libgmodule-2.0.so.0", check.MustAbs("/usr/lib/libgmodule-2.0.so.0"), 0x00007725f50df000},
+			{"libz.so.1", check.MustAbs("/usr/lib/libz.so.1"), 0x00007725f50c6000},
+			{"libmount.so.1", check.MustAbs("/usr/lib/libmount.so.1"), 0x00007725f5076000},
+			{"libffi.so.8", check.MustAbs("/usr/lib/libffi.so.8"), 0x00007725f506b000},
+			{"/lib64/ld-linux-x86-64.so.2", check.MustAbs("/usr/lib64/ld-linux-x86-64.so.2"), 0x00007725f5774000},
+			{"libblkid.so.1", check.MustAbs("/usr/lib/libblkid.so.1"), 0x00007725f5032000},
+		}, []*check.Absolute{
+			check.MustAbs("/lib64"),
+			check.MustAbs("/usr/lib"),
+			check.MustAbs("/usr/lib64"),
+		}},
 	}
 	for _, tc := range testCases {
 		t.Run(tc.file, func(t *testing.T) {
 			t.Parallel()
+
 			if got, err := ldd.Parse([]byte(tc.out)); err != nil {
-				t.Errorf("Parse() error = %v", err)
+				t.Errorf("Parse: error = %v", err)
 			} else if !reflect.DeepEqual(got, tc.want) {
-				t.Errorf("Parse() got = %#v, want %#v", got, tc.want)
+				t.Errorf("Parse: \n%s\nwant\n%s", mustMarshalJSON(got), mustMarshalJSON(tc.want))
+			} else if paths := ldd.Path(got); !reflect.DeepEqual(paths, tc.paths) {
+				t.Errorf("Paths: %v, want %v", paths, tc.paths)
 			}
 		})
 	}
 }
+
+// mustMarshalJSON calls [json.Marshal] and returns the resulting data.
+func mustMarshalJSON(v any) []byte {
+	if data, err := json.Marshal(v); err != nil {
+		panic(err)
+	} else {
+		return data
+	}
+}

ldd/path.go

@@ -1,20 +0,0 @@
-package ldd
-
-import (
-	"hakurei.app/container/check"
-)
-
-// Path returns a deterministic, deduplicated slice of absolute directory paths in entries.
-func Path(entries []*Entry) []*check.Absolute {
-	p := make([]*check.Absolute, 0, len(entries)*2)
-	for _, entry := range entries {
-		if a, err := check.NewAbs(entry.Path); err == nil {
-			p = append(p, a.Dir())
-		}
-		if a, err := check.NewAbs(entry.Name); err == nil {
-			p = append(p, a.Dir())
-		}
-	}
-	check.SortAbs(p)
-	return check.CompactAbs(p)
-}