1 files changed, 53 insertions, 0 deletions
diff --git a/internal/users.go b/internal/users.go
new file mode 100644
index 0000000..e7a25a3
--- /dev/null
+++ b/internal/users.go
@@ -0,0 +1,53 @@
+package internal
+
+import (
+	"bufio"
+	"errors"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// ListUsersWithHomeSubdir provides a list of user names on the current host.
+//
+// The users returned will only be those with a specifically named subdirectory
+// of their home dir, which has the given permission bits.
+func ListUsersWithHomeSubdir(subdir string, required_perms os.FileMode) ([]string, error) {
+	file, err := os.Open("/etc/passwd")
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		_ = file.Close()
+	}()
+
+	users := []string{}
+	rdr := bufio.NewReader(file)
+	for {
+		line, err := rdr.ReadString('\n')
+		isEOF := errors.Is(err, io.EOF)
+		if err != nil && !isEOF {
+			return nil, err
+		}
+
+		if len(line) != 0 && line[0] == '#' {
+			continue
+		}
+
+		spl := strings.Split(line, ":")
+		home := spl[len(spl)-2]
+		st, err := os.Stat(filepath.Join(home, subdir))
+		if err != nil || !st.IsDir() || st.Mode()&required_perms != required_perms {
+			continue
+		}
+
+		users = append(users, spl[0])
+
+		if isEOF {
+			break
+		}
+	}
+
+	return users, nil
+}