base: Add --installed flag to package selection

xbstrap/__init__.py

@@ -472,6 +472,9 @@ def select_pkgs(cfg, args):
         else:
             sel = [cfg.get_target_pkg(name) for name in args.packages]
 
+            if args.installed:
+                sel.extend(cfg.get_installed_pkgs())
+
             if args.deps_of is not None:
                 for pkg_name in args.deps_of:
                     pkg = cfg.get_target_pkg(pkg_name)
@@ -485,6 +488,7 @@ def select_pkgs(cfg, args):
 
 select_pkgs.parser = argparse.ArgumentParser(add_help=False)
 select_pkgs.parser.add_argument("--all", action="store_true")
+select_pkgs.parser.add_argument("--installed", action="store_true")
 select_pkgs.parser.add_argument("--deps-of", type=str, action="append")
 select_pkgs.parser.add_argument("packages", nargs="*", type=str)
 

xbstrap/base.py

@@ -763,6 +763,7 @@ def get_target_pkg(self, name):
             return pkg
         else:
             raise GenericError(f"Unknown package {name}")
+            raise GenericError(f"Unknown package {name}")
 
     def get_xbps_url(self, arch):
         xbps_yml = self._root_yml["repositories"]["xbps"]
@@ -796,6 +797,39 @@ def access_local_xbps_repodata(self, arch):
         index = _xbps_utils.read_repodata(rd_path)
         return index
 
+    def get_installed_pkgs(self):
+        if not self.use_xbps:
+            raise GenericError("Package management configuration cannot query installed packages")
+        environ = os.environ.copy()
+        _util.build_environ_paths(
+            environ, "PATH", prepend=[os.path.join(_util.find_home(), "bin")]
+        )
+
+        out = subprocess.check_output(
+            ["xbps-query", "-r", self.sysroot_dir, "-l"],
+            env=environ,
+            stderr=subprocess.DEVNULL,
+            encoding="utf-8",
+        )
+
+        # Lines have a format such as:
+        # "ii linux-headers-6.9.3_1            Linux kernel headers"
+        # "ii libexpat-2.5.0_6                 Stream-oriented XML parser library"
+        pattern = re.compile(r"^[\w?]+ ([^ ]+) ")
+        for line in out.splitlines():
+            match = pattern.match(line)
+            if not match:
+                raise GenericError(f"Unexpected line {repr(line)} from xbps-query")
+            pkgver = match.group(1)
+            name = pkgver.rsplit("-", maxsplit=1)[0]
+
+            pkg = self._target_pkgs.get(name)
+            if pkg is None:
+                continue
+            if not self.check_labels(pkg.label_set):
+                continue
+            yield pkg
+
 
 class ScriptStep:
     def __init__(self, step_yml, containerless=False):