53fe311bcd
We used to let mkfs.ext4 initialize the filesystem for us, but it turns out that the metadata attributes of the root directory were not being initialized from the source tree. In particular, this meant that the SELinu labels were left as unconfined_t, rather than root_t, which would not allow us to boot in enforcing mode. An alternative approach might be to fixup the root inode manually, while still doing the rest using mkfs.ext4, but let's leave that for the future if it turns out to be worth it. Signed-off-by: Tom Gundersen <teg@jklm.no>
96 lines
3.8 KiB
Python
Executable file
96 lines
3.8 KiB
Python
Executable file
#!/usr/bin/python3
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import contextlib
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import json
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import math
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import os
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import socket
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import subprocess
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import sys
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import tempfile
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import osbuild.remoteloop as remoteloop
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def tree_size(tree):
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size = 0
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for root, dirs, files in os.walk(tree):
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for entry in files + dirs:
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path = os.path.join(root, entry)
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size += os.stat(path, follow_symlinks=False).st_size
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return size
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@contextlib.contextmanager
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def mount(source, dest, *options):
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os.makedirs(dest, 0o755, True)
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subprocess.run(["mount", *options, source, dest], check=True)
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try:
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yield
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finally:
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subprocess.run(["umount", "-R", dest], check=True)
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@contextlib.contextmanager
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def mount_api(dest):
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with mount("/dev", f"{dest}/dev", "-o", "rbind"), \
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mount("/proc", f"{dest}/proc", "-o", "rbind"), \
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mount("/sys", f"{dest}/sys", "-o", "rbind"), \
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mount("none", f"{dest}/run", "-t", "tmpfs"):
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yield
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@contextlib.contextmanager
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def loop_device(loop_client, image, size, offset=0):
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fd = os.open(image, os.O_RDWR)
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devname = loop_client.create_device(fd, offset=offset, sizelimit=size)
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os.close(fd)
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path = f"/dev/{devname}"
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try:
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yield path
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finally:
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os.unlink(path)
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def main(tree, output_dir, options, loop_client):
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filename = options["filename"]
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root_fs_uuid = options["root_fs_uuid"]
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# Create a working directory on a tmpfs, maybe we should implicitly
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# always do this.
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with tempfile.TemporaryDirectory() as workdir:
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image = f"{workdir}/image.raw"
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mountpoint = f"{workdir}/mnt"
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# Create an empty image file of the right size
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size = int(math.ceil(tree_size(tree) * 1.2 / 512) * 512)
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subprocess.run(["truncate", "--size", str(size), image], check=True)
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# Set up the partition table of the image
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partition_table = "label: mbr\nbootable, type=83"
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subprocess.run(["sfdisk", "-q", image], input=partition_table, encoding='utf-8', check=True)
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r = subprocess.run(["sfdisk", "--json", image], stdout=subprocess.PIPE, encoding='utf-8', check=True)
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partition_table = json.loads(r.stdout)
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partition = partition_table["partitiontable"]["partitions"][0]
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partition_offset = partition["start"] * 512
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partition_size = partition["size"] * 512
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# Populate the first partition of the image with an ext4 fs and fill it with the contents of the
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# tree we are operating on.
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subprocess.run(["mkfs.ext4", "-U", root_fs_uuid, "-E", f"offset={partition_offset}", image,
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f"{int(partition_size / 1024)}k"], input="y", encoding='utf-8', check=True)
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# Mount the created image as a loopback device
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with loop_device(loop_client, image, partition_offset) as loop_block, \
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loop_device(loop_client, image, partition_size, partition_offset) as loop_part, \
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mount(loop_part, mountpoint):
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# Copy the tree into the target image
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subprocess.run(["cp", "-a", f"{tree}/.", mountpoint], check=True)
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# Install grub2 into the boot sector of the image, and copy the grub2 imagise into /boot/grub2
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with mount_api(mountpoint):
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subprocess.run(["chroot", mountpoint, "grub2-install", "--no-floppy",
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"--modules=part_msdos", "--target=i386-pc", loop_block], check=True)
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subprocess.run(["qemu-img", "convert", "-O", "qcow2", "-c", image, f"{output_dir}/{filename}"], check=True)
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if __name__ == '__main__':
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args = json.load(sys.stdin)
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sock = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
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sock.setsockopt(socket.SOL_SOCKET, socket.SO_PASSCRED, 1)
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sock.connect("/run/osbuild/api/remoteloop")
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ret = main(args["tree"], args["output_dir"], args["options"], remoteloop.LoopClient(sock))
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sys.exit(ret)
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