test: parse: add tests for bootimg parsing (MR 2477) (MR 2483)

Add some unit tests to ensure that the parser correctly detects boot
images with header v0, 2, and 3.

Signed-off-by: Caleb Connolly <caleb@postmarketos.org>

pmb/parse/test_bootimg.py

@@ -0,0 +1,114 @@
+from pathlib import Path
+from collections.abc import Callable
+import pytest
+import shutil
+import subprocess
+
+from pmb.types import Bootimg
+
+from .bootimg import bootimg as parse_bootimg
+
+
+"""
+This is the result of compiling a totally empty devicetree file:
+$ cat <<EOF | dtc -I dts -O dtb -o /tmp/empty.dtb
+/dts-v1/;
+
+/ {};
+EOF
+
+Then convert to python bytes:
+$ python -c 'print(open("/tmp/empty.dtb", "rb").read())'
+"""
+empty_dtb = b"\xd0\r\xfe\xed\x00\x00\x00H\x00\x00\x008\x00\x00\x00H\x00\x00\x00(\x00\x00\x00\x11\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x02\x00\x00\x00\t"
+
+
+@pytest.fixture
+def progs() -> dict[str, str]:
+    progs: dict[str, str] = {
+        # We expect the modern python version of mkbootimg from android-tools
+        "mkbootimg": "",
+    }
+    for k in progs.keys():
+        v = shutil.which(k)
+        if v is None:
+            pytest.skip(f"{k} not found")
+        else:
+            progs[k] = v
+
+    return progs
+
+
+@pytest.fixture
+def bootimg(progs: dict[str, str], tmp_path: Path) -> Callable:
+    path: Path = tmp_path / "boot.img"
+    cmd = [
+        progs["mkbootimg"],
+        "--kernel",
+        "/dev/null",
+        "--ramdisk",
+        "/dev/null",
+        "--output",
+        str(path),
+    ]
+
+    def with_args(**kwargs):
+        # Header version 2 requires a dtb file, be helpful and add one if it's missing
+        if kwargs.get("header_version", 0) == 2 and "dtb" not in kwargs:
+            with open(path.with_suffix(".dtb"), "wb") as f:
+                f.write(empty_dtb)
+            cmd.extend(["--dtb", str(path.with_suffix(".dtb"))])
+        for key, value in kwargs.items():
+            cmd.extend([f"--{key}", str(value)])
+        subprocess.run(cmd, check=True)
+        return tmp_path / "boot.img"
+
+    return with_args
+
+
+# Due to limitations in the test infrastructure (somehow we have to clone
+# all of pmaports for this!!) we stuff all the tests into one
+def test_bootimg(bootimg, pmb_args, pmaports):
+    bootimg_path = bootimg(base=0x80000000)
+
+    # Header v0
+    img: Bootimg = parse_bootimg(bootimg_path)
+    print(f"Header v0: {img}")
+    assert img["header_version"] == "0", "header v0 expected header version 0"
+    assert img["cmdline"] == "", "header v0 expected empty cmdline"
+    assert img["qcdt"] == "false", "header v0 expected qcdt false"
+    assert img["base"] == "0x80000000", "header v0 expected base 0x80000000"
+    assert int(img["kernel_offset"], 16) == 0x8000, "header v0 expected kernel offset 0x8000"
+    assert int(img["tags_offset"], 16) == 0x100, "header v0 expected tags offset 0x100"
+
+    # Header v2
+    bootimg_path = bootimg(base=0x80000000, header_version=2)
+
+    img = parse_bootimg(bootimg_path)
+    print(f"Header v2: {img}")
+    assert img["header_version"] == "2", "header v2 expected header version 2"
+    assert img["cmdline"] == "", "header v2 expected empty cmdline"
+    assert img["qcdt"] == "false", "header v2 expected qcdt false"
+    assert img["base"] == "0x80000000", "header v2 expected base 0x80000000"
+    assert int(img["kernel_offset"], 16) == 0x8000, "header v2 expected kernel offset 0x8000"
+    assert int(img["tags_offset"], 16) == 0x100, "header v2 expected tags offset 0x100"
+    assert img["dtb_offset"] is not None, "header v2 expected dtb offset"
+    assert int(img["dtb_offset"], 16) == 0x101F00000, "header v2 expected dtb offset 0x101f00000"
+    assert img["dtb_second"] == "", "header v2 expected dtb second empty"
+    assert img["pagesize"] == "2048", "header v2 expected pagesize 2048"
+
+    # Header v3, plus cmdline for fun
+    bootimg_path = bootimg(header_version=3, cmdline="bleep boop console=ttyMSM0,115200n8")
+
+    img = parse_bootimg(bootimg_path)
+    print(f"Header v3: {img}")
+    assert img["header_version"] == "3", "header v3 expected header version 3"
+    assert img["cmdline"] == "bleep boop console=ttyMSM0,115200n8", "header v3 expected cmdline"
+    assert img["kernel_offset"] == "", "header v3 expected empty kernel offset"
+    assert img["pagesize"] == "4096", "header v3 expected pagesize 4096"
+    assert img["ramdisk_offset"] == "", "header v3 expected empty ramdisk offset"
+
+
+def test_bootimg_deviceinfo():
+    # Test the deviceinfo file
+    pass