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backup: restore: handle VM data with qfile format instead of simple tar

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This was already partially implemented, but only for backup header
(qubes.xml).
Fix handling of vmproc object (available only when backup in another
VM).
Also fix some race conditions - wait for process termination, not only
check its exit code (which would be None if process still running).
This commit is contained in:
Marek Marczykowski-Górecki 2013-11-09 17:20:18 +01:00
parent c61a4570e8
commit 3c993c619c
1 changed files with 45 additions and 39 deletions
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84
core/qubesutils.py
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@ -1417,22 +1417,41 @@ def restore_vm_dirs (backup_dir, backup_tmpdir, passphrase, vms_dirs, vms, vms_s
vmproc = vm.run(command = backup_target, passio_popen = True)
vmproc.stdin.write(backup_dir.replace("\r","").replace("\n","")+"\n")
backup_stdin = vmproc.stdout
tar1_command = ['/usr/libexec/qubes/qfile-dom0-unpacker', str(os.getuid()), backup_tmpdir, '-v']
else:
backup_stdin = open(backup_dir,'rb')
# FIXME: Use a safer program such as cpio, modified uncompress.c, or try to extract it from
tar1_command = ['tar', '-i', '-xv', '-C', backup_tmpdir]
tar1_command.extend(vms_dirs)
tar1_command = ['tar', '-i', '-xvf', backup_dir, '-C', backup_tmpdir]
# Remove already processed qubes.xml.000, because qfile-dom0-unpacker will
# refuse to override files
os.unlink(os.path.join(backup_tmpdir,'qubes.xml.000'))
os.unlink(os.path.join(backup_tmpdir,'qubes.xml.000.hmac'))
tar1_env = os.environ.copy()
# TODO: add some safety margin?
tar1_env['UPDATES_MAX_BYTES'] = str(vms_size)
tar1_env['UPDATES_MAX_FILES'] = '0'
print_callback("Run command"+str(tar1_command))
command = subprocess.Popen(tar1_command, stdin=backup_stdin, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
command = subprocess.Popen(tar1_command,
stdin=backup_stdin,
stdout=vmproc.stdin if vmproc else subprocess.PIPE,
stderr=subprocess.PIPE,
env=tar1_env)
# qfile-dom0-unpacker output filelist on stderr (and have stdout connected
# to the VM), while tar output filelist on stdout
if appvm:
filelist_pipe = command.stderr
else:
filelist_pipe = command.stdout
while command.poll() == None and vmproc.poll() == None:
filename = command.stdout.readline().strip(" \t\r\n")
filename = filelist_pipe.readline().strip(" \t\r\n")
print_callback("Getting new file:"+filename)
hmacfile = command.stdout.readline().strip(" \t\r\n")
hmacfile = filelist_pipe.readline().strip(" \t\r\n")
print_callback("Getting hmac:"+hmacfile)
@ -1492,20 +1511,6 @@ def load_hmac(hmac):
return hmac
import struct
def get_qfile_error(buffer):
error = struct.unpack("I",buffer[0:4])[0]
error_msg = { 0: "COPY_FILE_OK",
1: "COPY_FILE_READ_EOF",
2: "COPY_FILE_READ_ERROR",
3: "COPY_FILE_WRITE_ERROR",
}
if error in error_msg.keys():
return error_msg[error]
else:
return "UNKNOWN_ERROR_"+str(error)
def backup_restore_header(restore_target, passphrase, encrypt=False, appvm=None):
# Simulate dd if=backup_file count=10 | file -
# Simulate dd if=backup_file count=10 | gpg2 -d | tar xzv -O
@ -1522,6 +1527,8 @@ def backup_restore_header(restore_target, passphrase, encrypt=False, appvm=None)
# For this reason, we will use named pipes instead
print "Working in",backup_tmpdir
tar1_env = os.environ.copy()
if appvm != None:
# Prepare the backup target (Qubes service call)
restore_command = "QUBESRPC qubes.Restore dom0"
@ -1540,20 +1547,25 @@ def backup_restore_header(restore_target, passphrase, encrypt=False, appvm=None)
# If APPVM, STDOUT is a PIPE
vmproc = vm.run(command = restore_command, passio_popen = True, passio_stderr = True)
vmproc.stdin.write(restore_target.replace("\r","").replace("\n","")+"\n")
tar1_command = ['/usr/libexec/qubes/qfile-dom0-unpacker', str(os.getuid()), backup_tmpdir, '-v']
# extract only qubes.xml.000 and qubes.xml.000.hmac
tar1_env['UPDATES_MAX_FILES'] = '2'
else:
# Create the target directory
# Check source file
if not os.path.exists (restore_target):
raise QubesException("ERROR: the backup directory {0} does not exists".format(restore_target))
fp = open(restore_target,'rb')
headers = fp.read(4096*16)
# TODO: perhaps pass only first 40kB here? Tar uses seek to skip files,
# so not a big problem, but still it might save some time
tar1_command = ['tar', '-i', '-xvf', restore_target, '-C', backup_tmpdir, 'qubes.xml.000', 'qubes.xml.000.hmac']
tar1_command = ['/usr/lib/qubes/qfile-dom0-unpacker', str(os.getuid()), backup_tmpdir]
command = subprocess.Popen(tar1_command,stdin=vmproc.stdout,stdout=subprocess.PIPE,stderr=subprocess.PIPE)
command = subprocess.Popen(tar1_command,
stdin=vmproc.stdout if vmproc else None,
stdout=vmproc.stdin if vmproc else subprocess.PIPE,
stderr=subprocess.PIPE,
env=tar1_env)
result_header = command.stdout.read()
if vmproc.poll() != None:
if vmproc and vmproc.poll() != None:
error = vmproc.stderr.read()
print error
print vmproc.poll(),command.poll()
@ -1561,29 +1573,23 @@ def backup_restore_header(restore_target, passphrase, encrypt=False, appvm=None)
filename = "qubes.xml.000"
print result_header.encode("hex")
error_msg = get_qfile_error(result_header)
if error_msg != "COPY_FILE_OK":
print vmproc.stdout.read()
raise QubesException("ERROR: unpacking backup headers: {0}".format(error_msg))
command.wait()
if not os.path.exists(os.path.join(backup_tmpdir,filename+".hmac")):
raise QubesException("ERROR: header not extracted correctly: {0}".format(os.path.join(backup_tmpdir,filename+".hmac")))
command.terminate()
command.wait()
if vmproc.poll() != None and vmproc.poll() != 0:
if vmproc and vmproc.poll() != None and vmproc.poll() != 0:
error = vmproc.stderr.read()
print error
print vmproc.poll(),command.poll()
raise QubesException("ERROR: VM error retrieving backup headers")
elif command.poll() != None and command.poll() not in [0,-15]:
elif command.returncode not in [0,-15,122]:
error = command.stderr.read()
print error
print vmproc.poll(),command.poll()
raise QubesException("ERROR: retrieving backup headers:{0}".format(error))
if vmproc.poll() == None:
if vmproc and vmproc.poll() == None:
vmproc.terminate()
vmproc.wait()