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