root/build-tools/build_guest/build-guest-image.py
Dean Troyer cfe45dadae StarlingX open source release updates
Signed-off-by: Dean Troyer <dtroyer@gmail.com>
2018-06-01 07:45:23 -07:00

124 lines
3.1 KiB
Python
Executable File

#!/usr/bin/env python
#
# Build a bootable guest image from the supplied rootfs archive
#
import getopt
import guestfs
import os
import sys
MBR_FILE='/usr/share/syslinux/mbr.bin'
MBR_SIZE=440
def build_image(inputfile, outputfile, extrasize, trace):
g = guestfs.GuestFS(python_return_dict=True)
# Set the trace flag so that we can see each libguestfs call.
if trace:
g.set_trace(1)
# Create a raw-format sparse disk image with padding of size
inputsize = os.path.getsize(inputfile)
g.disk_create(outputfile, "raw", inputsize + extrasize)
# Attach the new disk image to libguestfs.
g.add_drive_opts(outputfile, format="raw", readonly=0)
# Run the libguestfs back-end.
g.launch()
# Get the list of devices. Because we only added one drive
# above, we expect that this list should contain a single
# element.
devices = g.list_devices()
assert(len(devices) == 1)
# Partition the disk as one single MBR partition.
g.part_disk(devices[0], "mbr")
# Get the list of partitions. We expect a single element, which
# is the partition we have just created.
partitions = g.list_partitions()
assert(len(partitions) == 1)
# Create a filesystem on the partition.
# NOTE: extlinux does not support 64-bit file systems
g.mkfs("ext4", partitions[0], features="^64bit")
# Now mount the filesystem so that we can add files.
g.mount(partitions[0], "/")
# Upload file system files and directories.
g.tar_in(inputfile, "/")
# Install the boot loader
g.extlinux("/boot")
# Unmount the file systems.
g.umount_all();
# Write the master boot record.
with open(MBR_FILE, mode='rb') as mbr:
mbr_data = mbr.read()
assert(len(mbr_data) == MBR_SIZE)
g.pwrite_device(devices[0], mbr_data, 0)
# Mark the device as bootable.
g.part_set_bootable(devices[0], 1, 1)
# Label the boot disk for root identification
g.set_label(partitions[0], "wrs_guest")
# Shutdown and close guest image
g.shutdown()
g.close()
def exit_usage(result=0):
print('USAGE: -i <input-file> -o <output-file> [-s <extra-bytes>]')
sys.exit(result)
def main(argv):
inputfile = None
outputfile = None
extrasize = None
trace = False
try:
opts, args = getopt.getopt(argv,"hxi:o:s:",
["input=", "output=", "size="])
except getopt.GetoptError:
exit_usage(2)
for opt, arg in opts:
if opt == '-h':
exit_usage()
if opt == '-x':
trace = True
elif opt in ("-i", "--input"):
inputfile = arg
elif opt in ("-o", "--output"):
outputfile = arg
elif opt in ("-s", "--size"):
extrasize = int(arg)
if not inputfile:
print(stderr, "ERROR: missing input file")
exit_usage(-1)
if not outputfile:
print(stderr, "ERROR: missing output file")
exit_usage(-1)
if not extrasize:
extrasize = 0
build_image(inputfile, outputfile, extrasize, trace)
if __name__ == "__main__":
main(sys.argv[1:])