From 95582ee034f7b8e8647b454d9439140b2f7cd0db Mon Sep 17 00:00:00 2001
From: Clayton Craft <clayton@craftyguy.net>
Date: Sun, 12 Feb 2023 21:04:43 -0800
Subject: [PATCH] misc: add GetFiles and supporting functions

---
 internal/misc/getfiles.go | 163 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 163 insertions(+)
 create mode 100644 internal/misc/getfiles.go

diff --git a/internal/misc/getfiles.go b/internal/misc/getfiles.go
new file mode 100644
index 0000000..996cf21
--- /dev/null
+++ b/internal/misc/getfiles.go
@@ -0,0 +1,163 @@
+package misc
+
+import (
+	"debug/elf"
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+func GetFiles(list []string, required bool) (files []string, err error) {
+	for _, file := range list {
+		filelist, err := getFile(file, required)
+		if err != nil {
+			return nil, err
+		}
+		files = append(files, filelist...)
+	}
+
+	files = RemoveDuplicates(files)
+	return
+}
+
+func getFile(file string, required bool) (files []string, err error) {
+	// Expand glob expression
+	expanded, err := filepath.Glob(file)
+	if err != nil {
+		return
+	}
+	if len(expanded) > 0 && expanded[0] != file {
+		for _, path := range expanded {
+			if globFiles, err := getFile(path, required); err != nil {
+				return files, err
+			} else {
+				files = append(files, globFiles...)
+			}
+		}
+		return RemoveDuplicates(files), nil
+	}
+
+	fileInfo, err := os.Stat(file)
+	if err != nil {
+		if required {
+			return files, fmt.Errorf("getFile: failed to stat file %q: %w", file, err)
+		}
+		return files, nil
+	}
+
+	if fileInfo.IsDir() {
+		// Recurse over directory contents
+		err := filepath.Walk(file, func(path string, f os.FileInfo, err error) error {
+			if err != nil {
+				return err
+			}
+			if f.IsDir() {
+				return nil
+			}
+			newFiles, err := getFile(path, required)
+			if err != nil {
+				return err
+			}
+			files = append(files, newFiles...)
+			return nil
+		})
+		if err != nil {
+			return files, err
+		}
+	} else {
+		files = append(files, file)
+
+		// get dependencies for binaries
+		if _, err := elf.Open(file); err == nil {
+			if binaryDepFiles, err := getBinaryDeps(file); err != nil {
+				return files, err
+			} else {
+				files = append(files, binaryDepFiles...)
+			}
+		}
+	}
+
+	files = RemoveDuplicates(files)
+	return
+}
+
+func getDeps(file string, parents map[string]struct{}) (files []string, err error) {
+
+	if _, found := parents[file]; found {
+		return
+	}
+
+	// get dependencies for binaries
+	fd, err := elf.Open(file)
+	if err != nil {
+		return nil, fmt.Errorf("getDeps: unable to open elf binary %q: %w", file, err)
+	}
+	libs, _ := fd.ImportedLibraries()
+	fd.Close()
+	files = append(files, file)
+	parents[file] = struct{}{}
+
+	if len(libs) == 0 {
+		return
+	}
+
+	// we don't recursively search these paths for performance reasons
+	libdirGlobs := []string{
+		"/usr/lib",
+		"/lib",
+		"/usr/lib/expect*",
+	}
+
+	for _, lib := range libs {
+		found := false
+	findDepLoop:
+		for _, libdirGlob := range libdirGlobs {
+			libdirs, _ := filepath.Glob(libdirGlob)
+			for _, libdir := range libdirs {
+				path := filepath.Join(libdir, lib)
+				if _, err := os.Stat(path); err == nil {
+					binaryDepFiles, err := getDeps(path, parents)
+					if err != nil {
+						return nil, err
+					}
+					files = append(files, binaryDepFiles...)
+					files = append(files, path)
+					found = true
+					break findDepLoop
+				}
+			}
+		}
+		if !found {
+			return nil, fmt.Errorf("getDeps: unable to locate dependency for %q: %s", file, lib)
+		}
+	}
+
+	return
+}
+
+// Recursively list all dependencies for a given ELF binary
+func getBinaryDeps(file string) ([]string, error) {
+	// if file is a symlink, resolve dependencies for target
+	fileStat, err := os.Lstat(file)
+	if err != nil {
+		return nil, fmt.Errorf("getBinaryDeps: failed to stat file %q: %w", file, err)
+	}
+
+	// Symlink: write symlink to archive then set 'file' to link target
+	if fileStat.Mode()&os.ModeSymlink != 0 {
+		target, err := os.Readlink(file)
+		if err != nil {
+			return nil, fmt.Errorf("getBinaryDeps: unable to read symlink %q: %w", file, err)
+		}
+		if !filepath.IsAbs(target) {
+			target, err = RelativeSymlinkTargetToDir(target, filepath.Dir(file))
+			if err != nil {
+				return nil, err
+			}
+		}
+		file = target
+	}
+
+	return getDeps(file, make(map[string]struct{}))
+
+}