lorax/src/bin/mk-s390-cdboot

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#!/usr/bin/python3
#
# mk-s390-cdboot
#
# Copyright (C) 2017 Red Hat, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
import argparse
import os
import shutil
from struct import pack
import sys
INITRD_START = 0x0000000000800000
START_PSW_ADDRESS = 0x80010000
KERNEL_PSW_ADDRESS = 0x04
KERNEL_INITRD_START = 0x10408
KERNEL_INITRD_SIZE = 0x10410
KERNEL_CMDLINE = 0x10480
# See https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/s390/include/uapi/asm/setup.h
KERNEL_CMDLINE_SIZE = 896
def setup_parser():
""" Setup the cmdline parser"""
parser = argparse.ArgumentParser(description="Create s390 boot image")
parser.add_argument("-i", dest="kernel", required=True, metavar="KERNEL",
help="The kernel.img file")
parser.add_argument("-r", dest="ramdisk", required=True, metavar="RAMDISK",
help="The initrd.img file")
parser.add_argument("-p", dest="parmfile", required=True, metavar="PARMFILE",
help="The parm file")
parser.add_argument("-o", dest="outfile", required=True, metavar="OUTFILE",
help="The output image file")
return parser
def copy_kernel(kernel, outfile):
""" Copy the kernel to the outfile"""
shutil.copy2(kernel, outfile)
def append_ramdisk(ramdisk, outfile):
""" Append the ramdisk to the kernel and return its size"""
with open(ramdisk, "rb") as ram_fd:
with open(outfile, "r+b") as out_fd:
out_fd.seek(INITRD_START)
out_fd.write(ram_fd.read())
return os.stat(ramdisk).st_size
def configure_kernel(outfile, parmfile, size):
""" Configure the kernel with the ramdisk start address and size."""
with open(outfile, "r+b") as out_fd:
# Change the start PSW address
out_fd.seek(KERNEL_PSW_ADDRESS)
out_fd.write(pack(">L", START_PSW_ADDRESS))
# Write the initrd start and size
out_fd.seek(KERNEL_INITRD_START)
out_fd.write(pack(">Q", INITRD_START))
out_fd.seek(KERNEL_INITRD_SIZE)
out_fd.write(pack(">Q", size))
# Erase the previous COMMAND_LINE, write zeros
out_fd.seek(KERNEL_CMDLINE)
out_fd.write("\0" * KERNEL_CMDLINE_SIZE)
# Write the first line of the parmfile
cmdline = open(parmfile, "r").readline().strip()
out_fd.seek(KERNEL_CMDLINE)
out_fd.write(cmdline)
def main():
parser = setup_parser()
args = parser.parse_args()
errors = []
for f in [args.kernel, args.ramdisk, args.parmfile]:
if not os.path.exists(f):
errors.append("ERROR: %s is missing" % f)
if errors:
for e in errors:
print(e)
sys.exit(1)
print("Creating bootable CD-ROM image...")
print("kernel is : %s" % args.kernel)
print("ramdisk is : %s" % args.ramdisk)
print("parmfile is: %s" % args.parmfile)
print("outfile is : %s" % args.outfile)
copy_kernel(args.kernel, args.outfile)
size = append_ramdisk(args.ramdisk, args.outfile)
configure_kernel(args.outfile, args.parmfile, size)
if __name__ == '__main__':
main()