forked from Mirror/pmbootstrap
31cc898dd5
With the new chroot type, we can now write fancy paths in the pythonic way. Convert most of the codebase over, as well as adding various other type hints. Signed-off-by: Caleb Connolly <caleb@postmarketos.org>
120 lines
3.9 KiB
Python
120 lines
3.9 KiB
Python
# Copyright 2023 Oliver Smith
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# SPDX-License-Identifier: GPL-3.0-or-later
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import os
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from pathlib import Path, PurePath
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from typing import List
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from pmb.core.types import PmbArgs
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import pmb.helpers
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from pmb.core import Chroot
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import pmb.helpers.run
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def ismount(folder: Path):
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"""Ismount() implementation that works for mount --bind.
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Workaround for: https://bugs.python.org/issue29707
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"""
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folder = folder.resolve()
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with open("/proc/mounts", "r") as handle:
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for line in handle:
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words = line.split()
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if len(words) >= 2 and Path(words[1]) == folder:
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return True
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if words[0] == folder:
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return True
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return False
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def bind(args: PmbArgs, source: Path, destination: Path, create_folders=True, umount=False):
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"""Mount --bind a folder and create necessary directory structure.
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:param umount: when destination is already a mount point, umount it first.
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"""
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# Check/umount destination
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if ismount(destination):
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if umount:
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umount_all(args, destination)
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else:
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return
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print(f"Mounting {source} -> {destination}")
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# Check/create folders
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for path in [source, destination]:
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if os.path.exists(path):
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continue
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if create_folders:
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pmb.helpers.run.root(args, ["mkdir", "-p", path])
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else:
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raise RuntimeError(f"Mount failed, folder does not exist: {path}")
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# Actually mount the folder
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pmb.helpers.run.root(args, ["mount", "--bind", source, destination])
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# Verify that it has worked
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if not ismount(destination):
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raise RuntimeError(f"Mount failed: {source} -> {destination}")
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def bind_file(args: PmbArgs, source: Path, destination: Path, create_folders=False):
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"""Mount a file with the --bind option, and create the destination file, if necessary."""
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# Skip existing mountpoint
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if ismount(destination):
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return
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# Create empty file
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if not destination.exists():
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if create_folders:
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dest_dir: Path = destination.parent
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if not dest_dir.is_dir():
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pmb.helpers.run.root(args, ["mkdir", "-p", dest_dir])
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pmb.helpers.run.root(args, ["touch", destination])
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# Mount
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pmb.helpers.run.root(args, ["mount", "--bind", source,
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destination])
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def umount_all_list(prefix: Path, source: Path=Path("/proc/mounts")) -> List[Path]:
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"""Parse `/proc/mounts` for all folders beginning with a prefix.
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:source: can be changed for testcases
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:returns: a list of folders that need to be umounted
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"""
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ret = []
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prefix = prefix.resolve()
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with source.open() as handle:
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for line in handle:
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words = line.split()
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if len(words) < 2:
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raise RuntimeError(f"Failed to parse line in {source}: {line}")
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mountpoint = Path(words[1].replace(r"\040(deleted)", ""))
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if mountpoint.is_relative_to(prefix): # is subpath
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ret.append(mountpoint)
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ret.sort(reverse=True)
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return ret
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def umount_all(args: PmbArgs, folder: Path):
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"""Umount all folders that are mounted inside a given folder."""
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for mountpoint in umount_all_list(folder):
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pmb.helpers.run.root(args, ["umount", mountpoint])
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if ismount(mountpoint):
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raise RuntimeError(f"Failed to umount: {mountpoint}")
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def mount_device_rootfs(args: PmbArgs, chroot_rootfs: Chroot) -> PurePath:
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"""
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Mount the device rootfs.
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:param chroot_rootfs: the chroot where the rootfs that will be
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installed on the device has been created (e.g.
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"rootfs_qemu-amd64")
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:returns: the mountpoint (relative to the native chroot)
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"""
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mountpoint = PurePath("/mnt", chroot_rootfs.dirname)
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pmb.helpers.mount.bind(args, chroot_rootfs.path,
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Chroot.native() / mountpoint)
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return mountpoint
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