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#!/usr/bin/python3
import sys
import os
from fcntl import ioctl
import struct
import argparse
import errno
import textwrap
def fail(message):
print(textwrap.fill("FICLONERANGE: " + message))
sys.exit(3)
FICLONERANGE = 0x4020940d
def struct_file_clone_range(src_fd, src_offset, src_length, dst_offset):
return struct.pack("qQQQ", src_fd, src_offset, src_length, dst_offset)
parser = argparse.ArgumentParser(description="Reflink bytes from source file to destination. "
"If no optional parameters are provided, append contents of src to dest. See ioctl_ficlonerange(2) for details.")
parser.add_argument("-s", type=int, default=0, help="Source file offset in bytes (default: 0)")
parser.add_argument("-l", type=int, default=0, help="Number of bytes to reflink (default: all data)")
parser.add_argument("-d", type=int, help="Destination file offset in bytes (default: end of file)")
parser.add_argument("src", help="Source filename")
parser.add_argument("dest", help="Destination filename")
args = parser.parse_args()
src_fd = os.open(args.src, os.O_RDONLY)
dst_fd = os.open(args.dest, os.O_WRONLY)
try:
ioctl(dst_fd, FICLONERANGE, struct_file_clone_range(src_fd,
args.s or 0,
args.l or 0,
args.d if args.d is not None else os.fstat(dst_fd).st_size,
))
except OSError as e:
if e.errno == errno.EXDEV:
fail("src and dest are not on the same mounted filesystem")
if e.errno == errno.EISDIR:
fail("One of the files is a directory and the filesystem does not support shared regions in directories.")
if e.errno == errno.EINVAL:
fail("The filesystem does not support reflinking the ranges of the given files. This error can also appear "
"if either file descriptor represents a device, FIFO, or socket. Disk filesystems generally require the "
"offset and length arguments to be aligned to the fundamental block size ({} bytes). XFS and Btrfs do not support "
"overlapping reflink ranges in the same file.".format(os.fstat(dst_fd).st_blksize))
if e.errno == errno.EBADF:
fail("Filesystem does not support reflink (EBADF).")
if e.errno == errno.EPERM:
fail("dest is immutable.")
if e.errno == errno.ETXTBSY:
fail("One of the files is a swap file. Swap files cannot share storage.")
if e.errno == errno.EOPNOTSUPP:
fail("Filesystem does not support reflink (EOPNOTSUPP).")
raise
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