pmbootstrap-meow/pmb/chroot/mount.py

186 lines
6.7 KiB
Python

# Copyright 2023 Oliver Smith
# SPDX-License-Identifier: GPL-3.0-or-later
from pmb.core.chroot import ChrootType
from pmb.core.pkgrepo import pkgrepo_default_path
from pmb.helpers import logging
import os
from pathlib import Path
import pmb.chroot.binfmt
import pmb.config
import pmb.helpers.run
import pmb.parse
import pmb.install.losetup
import pmb.helpers.mount
from pmb.core import Chroot
from pmb.core.context import get_context
def mount_chroot_image(chroot: Chroot) -> None:
"""Mount an IMAGE type chroot, to modify an existing rootfs image. This
doesn't support split images yet!"""
# Make sure everything is nicely unmounted just to be super safe
# this is definitely overkill
pmb.chroot.shutdown()
pmb.install.losetup.detach_all()
chroot_native = Chroot.native()
pmb.chroot.init(chroot_native)
loopdev = pmb.install.losetup.mount(
Path("/") / Path(chroot.name).relative_to(chroot_native.path)
)
pmb.helpers.mount.bind_file(loopdev, chroot_native / "dev/install")
# Set up device mapper bits
pmb.helpers.run.root(["kpartx", "-u", loopdev])
chroot.path.mkdir(exist_ok=True)
loopdev_basename = os.path.basename(loopdev)
# # The name of the IMAGE chroot is the path to the rootfs image
if Path(f"/dev/mapper/{loopdev_basename}p2").exists():
pmb.helpers.run.root(["mount", f"/dev/mapper/{loopdev_basename}p2", chroot.path])
pmb.helpers.run.root(["mount", f"/dev/mapper/{loopdev_basename}p1", chroot.path / "boot"])
else:
pmb.helpers.run.root(["mount", f"/dev/{loopdev_basename}", chroot.path])
pmb.config.workdir.chroot_save_init(chroot)
logging.info(f"({chroot}) mounted {chroot.name}")
def create_device_nodes(chroot: Chroot) -> None:
"""
Create device nodes for null, zero, full, random, urandom in the chroot.
"""
try:
# Create all device nodes as specified in the config
for dev in pmb.config.chroot_device_nodes:
path = chroot / "dev" / str(dev[4])
if not path.exists():
pmb.helpers.run.root(
[
"mknod",
path, # name
str(dev[1]), # type
str(dev[2]), # major
str(dev[3]), # minor
]
)
# chmod needs to be split from mknod to accommodate
# for FreeBSD mknod not including -m
pmb.helpers.run.root(
[
"chmod",
str(dev[0]), # permissions
path, # name
]
)
# Verify major and minor numbers of created nodes
for dev in pmb.config.chroot_device_nodes:
path = chroot / "dev" / str(dev[4])
stat_result = path.stat()
rdev = stat_result.st_rdev
assert os.major(rdev) == dev[2], f"Wrong major in {path}"
assert os.minor(rdev) == dev[3], f"Wrong minor in {path}"
# Verify /dev/zero reading and writing
path = chroot / "dev/zero"
with open(path, "r+b", 0) as handle:
assert handle.write(bytes([0xFF])), f"Write failed for {path}"
assert handle.read(1) == bytes([0x00]), f"Read failed for {path}"
# On failure: Show filesystem-related error
except Exception as e:
logging.info(str(e) + "!")
raise RuntimeError(f"Failed to create device nodes in the '{chroot}' chroot.")
def mount_dev_tmpfs(chroot: Chroot = Chroot.native()) -> None:
"""
Mount tmpfs inside the chroot's dev folder to make sure we can create
device nodes, even if the filesystem of the work folder does not support
it.
"""
# Do nothing when it is already mounted
dev = chroot / "dev"
if pmb.helpers.mount.ismount(dev):
return
# Create the $chroot/dev folder and mount tmpfs there
pmb.helpers.run.root(["mkdir", "-p", dev])
pmb.helpers.run.root(["mount", "-t", "tmpfs", "-o", "size=1M,noexec,dev", "tmpfs", dev])
# Create pts, shm folders and device nodes
pmb.helpers.run.root(["mkdir", "-p", dev / "pts", dev / "shm"])
pmb.helpers.run.root(
["mount", "-t", "tmpfs", "-o", "nodev,nosuid,noexec", "tmpfs", dev / "shm"]
)
create_device_nodes(chroot)
# Setup /dev/fd as a symlink
pmb.helpers.run.root(["ln", "-sf", "/proc/self/fd", f"{dev}/"])
def mount(chroot: Chroot) -> None:
if chroot.type == ChrootType.IMAGE and not pmb.mount.ismount(chroot.path):
mount_chroot_image(chroot)
# Mount tmpfs as the chroot's /dev
mount_dev_tmpfs(chroot)
# Get all mountpoints
arch = chroot.arch
channel = pmb.config.pmaports.read_config(pkgrepo_default_path())["channel"]
mountpoints: dict[Path, Path] = {}
for src_template, target_template in pmb.config.chroot_mount_bind.items():
src_template = src_template.replace("$WORK", os.fspath(get_context().config.work))
src_template = src_template.replace("$ARCH", str(arch))
src_template = src_template.replace("$CHANNEL", channel)
mountpoints[Path(src_template)] = Path(target_template)
# Mount if necessary
for source, target in mountpoints.items():
target_outer = chroot / target
if not pmb.helpers.mount.ismount(target_outer):
pmb.helpers.mount.bind(source, target_outer)
# Set up binfmt
if not arch.cpu_emulation_required():
return
arch_qemu = arch.qemu()
# mount --bind the qemu-user binary
pmb.chroot.binfmt.register(arch)
pmb.helpers.mount.bind_file(
Chroot.native() / f"usr/bin/qemu-{arch_qemu}",
chroot / f"usr/bin/qemu-{arch_qemu}-static",
create_folders=True,
)
def mount_native_into_foreign(chroot: Chroot) -> None:
source = Chroot.native().path
target = chroot / "native"
pmb.helpers.mount.bind(source, target)
musl = next(source.glob("lib/ld-musl-*.so.1")).name
musl_link = chroot / "lib" / musl
if not musl_link.is_symlink():
pmb.helpers.run.root(["ln", "-s", "/native/lib/" + musl, musl_link])
# pmb.helpers.run.root(["ln", "-sf", "/native/usr/bin/pigz", "/usr/local/bin/pigz"])
def remove_mnt_pmbootstrap(chroot: Chroot) -> None:
"""Safely remove /mnt/pmbootstrap directories from the chroot, without
running rm -r as root and potentially removing data inside the
mountpoint in case it was still mounted (bug in pmbootstrap, or user
ran pmbootstrap 2x in parallel). This is similar to running 'rm -r -d',
but we don't assume that the host's rm has the -d flag (busybox does
not)."""
mnt_dir = chroot / "mnt/pmbootstrap"
if not mnt_dir.exists():
return
for path in [*mnt_dir.glob("*"), mnt_dir]:
pmb.helpers.run.root(["rmdir", path])