117 lines
4.5 KiB
Python
Executable file
117 lines
4.5 KiB
Python
Executable file
#!/usr/bin/python3
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import contextlib
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import json
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import os
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import socket
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import shutil
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import subprocess
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import sys
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import osbuild.remoteloop as remoteloop
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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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def main(tree, output_dir, options, loop_client):
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fmt = options["format"]
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filename = options["filename"]
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ptuuid = options["ptuuid"]
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root_fs_uuid = options["root_fs_uuid"]
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size = options["size"]
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# sfdisk works on sectors of 512 bytes and ignores excess space - be explicit about this
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if size % 512 != 0:
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raise ValueError("`size` must be a multiple of sector size (512)")
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if fmt not in ["raw", "qcow2", "vdi", "vmdk"]:
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raise ValueError("`format` must be one of raw, qcow, vdi, vmdk")
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image = f"/var/tmp/osbuild-image.raw"
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grub2_core = "/var/tmp/grub2-core.img"
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grub2_load = "/var/tmp/grub2-load.cfg"
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mountpoint = f"/tmp/osbuild-mnt"
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# Create an empty image file
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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 = f"label: mbr\nlabel-id: {ptuuid}\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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with open(grub2_load, "w") as load:
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load.write(f"search.fs_uuid {root_fs_uuid} root \n"
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"set prefix=($root)'/boot/grub2'\n")
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# Create the level-2 bootloader
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# The purpose of this is to find the grub modules and configuration
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# to be able to start the level-3 bootloader. It contains the modules
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# necessary to do this, but nothing else.
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subprocess.run(["grub2-mkimage",
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"--verbose",
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"--directory", "/usr/lib/grub/i386-pc",
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"--prefix", "/boot/grub2",
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"--format", "i386-pc",
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"--compression", "auto",
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"--config", grub2_load,
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"--output", grub2_core,
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"part_msdos", "ext2", "biosdisk", "search_fs_uuid"],
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check=True)
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assert os.path.getsize(grub2_core) < partition_offset - 512
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with open(image, "rb+") as image_f:
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# Install the level-1 bootloader into the start of the MBR
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# The purpose of this is simply to jump into the level-2 bootloader.
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with open("/usr/lib/grub/i386-pc/boot.img", "rb") as boot_f:
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# The boot.img file is 512 bytes, but we must only copy the first 440
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# bytes, as these contain the bootstrapping code. The rest of the
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# first sector contains the partition table, and must not be
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# overwritten.
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image_f.write(boot_f.read(440))
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# Install the level-2 bootloader into the space after the MBR, before
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# the first partition.
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with open(grub2_core, "rb") as core_f:
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image_f.seek(512)
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shutil.copyfileobj(core_f, image_f)
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# Populate the first partition of the image with an ext4 fs
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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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# Copy the tree into the target image
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with loop_client.device(image, partition_offset, partition_size) as loop, \
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mount(loop, mountpoint):
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subprocess.run(["cp", "-a", f"{tree}/.", mountpoint], check=True)
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extra_args = []
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# raw and vdi don't suppport compression
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if fmt != "raw" and fmt != "vdi":
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extra_args.append("-c")
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subprocess.run(["qemu-img", "convert", "-O", fmt, *extra_args, 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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with socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM) as sock:
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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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