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#
# XendBootloader.py - Framework to run a boot loader for picking the kernel
#
# Copyright 2005-2006 Red Hat, Inc.
# Jeremy Katz <katzj@redhat.com>
#
# This software may be freely redistributed under the terms of the GNU
# general public license.
#
# 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., 675 Mass Ave, Cambridge, MA 02139, USA.
#
import os, select, errno
import random
import sxp
import shlex
from XendLogging import log
from XendError import VmError
def bootloader(blexec, disk, quiet = 0, blargs = None, imgcfg = None):
"""Run the boot loader executable on the given disk and return a
config image.
@param blexec Binary to use as the boot loader
@param disk Disk to run the boot loader on.
@param quiet Run in non-interactive mode, just booting the default.
@param blargs Arguments to pass to the bootloader."""
if not os.access(blexec, os.X_OK):
msg = "Bootloader isn't executable"
log.error(msg)
raise VmError(msg)
if not os.access(disk, os.R_OK):
msg = "Disk isn't accessible"
log.error(msg)
raise VmError(msg)
while True:
fifo = "/var/lib/xen/xenbl.%s" %(random.randint(0, 32000),)
if not os.path.exists(fifo):
break
os.mkfifo(fifo, 0600)
child = os.fork()
if (not child):
args = [ blexec ]
if quiet:
args.append("-q")
args.append("--output=%s" %(fifo,))
if blargs is not None:
args.extend(shlex.split(blargs))
args.append(disk)
try:
os.execvp(args[0], args)
except OSError, e:
print e
pass
os._exit(1)
while 1:
try:
r = os.open(fifo, os.O_RDONLY)
except OSError, e:
if e.errno == errno.EINTR:
continue
break
ret = ""
while 1:
select.select([r], [], [])
s = os.read(r, 1024)
ret = ret + s
if len(s) == 0:
break
os.waitpid(child, 0)
os.close(r)
os.unlink(fifo)
if len(ret) == 0:
msg = "Boot loader didn't return any data!"
log.error(msg)
raise VmError, msg
pin = sxp.Parser()
pin.input(ret)
pin.input_eof()
blcfg = pin.val
if imgcfg is None:
return blcfg
else:
c = sxp.merge(blcfg, imgcfg)
return c
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