Port rootfs.sh to Python

rootfs.py

@@ -0,0 +1,103 @@
+#!/usr/bin/env python3
+"""
+A helper application used to start bootstrapping process.
+It has a few modes of operation, you can create initramfs with
+binary seeds and sources that you can boot into or alternatively
+you can run bootstap inside chroot.
+"""
+
+# SPDX-License-Identifier: GPL-3.0-or-later
+# SPDX-FileCopyrightText: 2021 Andrius Štikonas <andrius@stikonas.eu>
+
+import argparse
+import glob
+import os
+import subprocess
+
+from sysa import SysA
+from lib.utils import run
+
+def main():
+    """
+    A few command line arguments to customize bootstrap.
+    This function also creates SysA object which prepares directory
+    structure with bootstrap seeds and all sources.
+    """
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-a", "--arch", help="Bootstrap architecture",
+                        default="x86")
+    parser.add_argument("-c", "--chroot", help="Run inside chroot",
+                        action="store_true")
+    parser.add_argument("-p", "--preserve", help="Do not unmount temporary dir",
+                        action="store_true")
+    parser.add_argument("-t", "--tmpdir", help="Temporary directory")
+
+    # QEMU arguments
+    parser.add_argument("-q", "--qemu-cmd", help="QEMU command",
+                        default="qemu-system-x86_64")
+    parser.add_argument("-r", "--qemu-ram", help="Memory (in megabytes) allocated to QEMU VM",
+                        default=8000)
+    parser.add_argument("-k", "--kernel", help="Kernel to use (default is ./kernel)",
+                        default="kernel")
+
+    parser.add_argument("-m", "--minikernel", help="Use minikernel",
+                        action="store_true")
+
+    args = parser.parse_args()
+    if args.chroot and args.minikernel:
+        raise ValueError("chroot and minikernel options cannot be used simultaneously.")
+
+    if args.arch != "x86":
+        raise ValueError("Only x86 is supported at the moment.")
+
+    system_a = SysA(arch=args.arch, preserve_tmp=args.preserve, tmpdir=args.tmpdir)
+    initramfs_path = os.path.join(system_a.tmp_dir, "initramfs")
+
+    if not args.chroot:
+        make_initramfs(system_a.tmp_dir, initramfs_path)
+
+    bootstrap(args, system_a.tmp_dir, initramfs_path)
+
+def make_initramfs(tmp_dir, initramfs_path):
+    """Package binary bootstrap seeds and sources into initramfs."""
+    file_list = glob.glob(os.path.join(tmp_dir, '**'), recursive=True)
+
+    # Use built-in removeprefix once we can use Python 3.9
+    def remove_prefix(text, prefix):
+        if text.startswith(prefix):
+            return text[len(prefix):]
+        return text  # or whatever
+
+    file_list = [remove_prefix(f, tmp_dir + os.sep) for f in file_list]
+
+    with open(initramfs_path, "w") as initramfs:
+        cpio = subprocess.Popen(["cpio", "--format", "newc", "--create", "--directory", tmp_dir],
+                             stdin=subprocess.PIPE, stdout=initramfs)
+        cpio.communicate(input='\n'.join(file_list).encode())
+
+def bootstrap(args, tmp_dir, initramfs_path):
+    """Kick off bootstrap process."""
+    print("Bootstrapping %s" % (args.arch))
+    if args.chroot:
+        init = os.path.join(os.sep, 'bootstrap-seeds', 'POSIX', args.arch, 'kaem-optional-seed')
+        run('sudo', 'env', '-i', 'PATH=/bin', 'chroot', tmp_dir, init)
+        return
+
+    if args.minikernel:
+        run('git', 'clone', '--depth', '1', '--branch', 'v0.4',
+            'https://github.com/bittorf/kritis-linux.git')
+        run('kritis-linux/ci_helper.sh', '--arch', 'x86_64', '--ramsize',
+            '-m', str(args.qemu_ram) + 'M', '--kernel', '5.10.8', '--initrd', initramfs_path)
+        return
+
+    run(args.qemu_cmd,
+        '-enable-kvm',
+        '-m', str(args.qemu_ram) + 'M',
+        '-nographic',
+        '-no-reboot',
+        '-kernel', args.kernel,
+        '-initrd', initramfs_path,
+        '-append', "console=ttyS0")
+
+if __name__=="__main__":
+    main()