feat(helperFunctions): Introduce magic

src/helperFunctions/magic.py

@@ -0,0 +1,46 @@
+"""This is a wrapper around pymagic.
+It aims to provide the same API but with the ability to load multiple magic
+files in the default api.
+"""
+from __future__ import annotations
+
+import os
+from os import PathLike
+
+import magic as pymagic
+
+from helperFunctions.fileSystem import get_src_dir
+
+# On ubuntu this is provided by the libmagic-mgc package
+_default_magic = os.getenv('MAGIC', '/usr/lib/file/magic.mgc')
+_fact_magic = f'{get_src_dir()}/bin/firmware.mgc'
+_internal_symlink_magic = f'{get_src_dir()}/bin/internal_symlink_magic.mgc'
+_magic_file = f'{_internal_symlink_magic}:{_fact_magic}:{_default_magic}'
+
+_instances = {}
+
+
+def _get_magic_instance(**kwargs):
+    """Returns an instance of pymagic.Maigc"""
+    # Dicts are not hashable but sorting and creating a tuple is a valid hash
+    key = hash(tuple(sorted(kwargs.items())))
+    instance = _instances.get(key)
+    if instance is None:
+        instance = _instances[key] = pymagic.Magic(**kwargs)
+    return instance
+
+
+def from_file(filename: bytes | str | PathLike, magic_file: str | None = _magic_file, **kwargs) -> str:
+    """Like pymagic's ``magic.from_file`` but it accepts all keyword arguments
+    that ``magic.Magic`` accepts.
+    """
+    m = _get_magic_instance(magic_file=magic_file, **kwargs)
+    return m.from_file(filename)
+
+
+def from_buffer(buf: bytes | str, magic_file: str | None = _magic_file, **kwargs) -> str:
+    """Like pymagic's ``magic.from_buffer`` but it accepts all keyword arguments
+    that ``magic.Magic`` accepts.
+    """
+    instance = _get_magic_instance(magic_file=magic_file, **kwargs)
+    return instance.from_buffer(buf)

src/install/common.py

@@ -46,6 +46,13 @@ def main(distribution):
 
     BIN_DIR.mkdir(exist_ok=True)
 
+    run_cmd_with_logging(
+        f'wget -O {BIN_DIR / "firmware"} https://github.com/fkie-cad/firmware-magic-database/releases/download/v0.2.0/firmware'
+    )
+    run_cmd_with_logging(f'file -C -m {BIN_DIR / "firmware"}')
+    run_cmd_with_logging(f'file -C -m {INSTALL_DIR / "internal_symlink_magic"}')
+    run_cmd_with_logging(f'mv {INSTALL_DIR / "internal_symlink_magic.mgc"} {BIN_DIR}')
+
     apt_packages_path = INSTALL_DIR / 'apt-pkgs-common.txt'
     dnf_packages_path = INSTALL_DIR / 'dnf-pkgs-common.txt'
 

src/install/internal_symlink_magic

@@ -0,0 +1,6 @@
+# ====================== fact internal ======================
+
+# ---- fact internal link representation ----
+0		string  symbolic\ link\ ->	 symbolic link
+>17		string 	x		to '%s'
+!:mime  inode/symlink

src/test/unit/helperFunctions/test_magic.py

@@ -0,0 +1,13 @@
+from helperFunctions import magic
+
+
+def test_internal_magic():
+    assert magic.from_buffer('symbolic link -> /foo/bar', mime=True) == 'inode/symlink'
+
+
+def test_firmware_magic():
+    assert magic.from_buffer('BOOTLOADER!', mime=False) == 'Mediatek bootloader'
+
+
+def test_magic_from_file():
+    assert magic.from_file('/dev/null', mime=True) == 'inode/chardevice'