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# Copyright (C) 2006, 2007, 2008 Lars Wirzenius <liw@iki.fi>
#
# 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, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
"""Rsync stuff for making backups"""
import logging
import os
import subprocess
import tempfile
import obnam
class UnknownCommand(obnam.ObnamException):
def __init__(self, argv, errno):
self._msg = "Unknown command (error %d): %s" % (errno, " ".join(argv))
class CommandFailure(obnam.ObnamException):
def __init__(self, argv, returncode, stderr):
self._msg = "Command failed: %s\nError code: %d\n%s" % \
(" ".join(argv),
returncode,
obnam.gpg.indent_string(stderr))
def run_command(argv, stdin=None, stdout=None, stderr=None):
# We let stdin be None unless explicitly specified.
if stdout is None:
stdout = subprocess.PIPE
if stderr is None:
stderr = subprocess.PIPE
try:
p = subprocess.Popen(argv, stdin=stdin, stdout=stdout, stderr=stderr)
except os.error, e:
raise UnknownCommand(argv, e.errno)
return p
def compute_signature(context, filename):
"""Compute an rsync signature for 'filename'"""
argv = [context.config.get("backup", "odirect-pipe"),
context.config.get("backup", "odirect-read"),
filename,
"rdiff", "--", "signature", "-", "-"]
p = run_command(argv)
stdout_data, stderr_data = p.communicate()
if p.returncode == 0:
return stdout_data
else:
raise CommandFailure(argv, p.returncode, stderr_data)
def compute_delta(context, signature, filename):
"""Compute an rsync delta for a file, given signature of old version
Return list of ids of DELTAPART objects.
"""
(fd, tempname) = tempfile.mkstemp()
os.write(fd, signature)
os.close(fd)
argv = [context.config.get("backup", "odirect-pipe"),
context.config.get("backup", "odirect-read"),
filename,
"rdiff", "--", "delta", tempname, "-", "-"]
p = run_command(argv)
list = []
block_size = context.config.getint("backup", "block-size")
while True:
data = p.stdout.read(block_size)
if not data:
break
id = obnam.obj.object_id_new()
o = obnam.obj.DeltaPartObject(id=id)
o.add(obnam.cmp.Component(obnam.cmp.DELTADATA, data))
o = o.encode()
obnam.io.enqueue_object(context, context.content_oq,
context.contmap, id, o, False)
list.append(id)
exit = p.wait()
os.remove(tempname)
if exit == 0:
return list
else:
raise CommandFailure(argv, exit, "")
def apply_delta(context, basis, deltaparts, new, open=os.open, cmd="rdiff"):
"""Apply an rsync delta for a file, to get a new version of it"""
devnull = open("/dev/null", os.O_WRONLY)
argv = [cmd, "--", "patch", basis, "-", new]
p = run_command(argv, stdin=subprocess.PIPE, stdout=devnull)
ret = True
for id in deltaparts:
deltapart = obnam.io.get_object(context, id)
deltadata = deltapart.first_string_by_kind(obnam.cmp.DELTADATA)
p.stdin.write(deltadata)
stdout_data, stderr_data = p.communicate(input="")
os.close(devnull)
if p.returncode != 0:
raise CommandFailure(argv, p.returncode, stderr_data)
else:
return ret
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