# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1222940248 -3600
# Node ID 60937c4c5a673d3b2179255e0f9b2e17bfd8f8be
# Parent ab19284c5070b8603a89bb757eff77b4420d1925
xend: Make only selected subdirs of /local/domain/<domid> writable by the guest.
This protects critical data like
/local/domain/<domid>/console/{tty,limit}. It also means we can trust
.../vm, and hence do not need /vm_path. Various parts of the previous
two changesets disappear.
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
tools/python/xen/xend/XendDomainInfo.py | 57 ++++++++++++++++++++++----------
tools/python/xen/xend/image.py | 4 +-
2 files changed, 42 insertions(+), 19 deletions(-)
diff -r ab19284c5070 -r 60937c4c5a67 tools/python/xen/xend/XendDomainInfo.py
--- a/tools/python/xen/xend/XendDomainInfo.py Wed Oct 01 14:07:17 2008 +0100
+++ b/tools/python/xen/xend/XendDomainInfo.py Thu Oct 02 10:37:28 2008 +0100
@@ -142,7 +142,9 @@ def recreate(info, priv):
xeninfo['is_control_domain'] = priv
xeninfo['is_a_template'] = False
domid = xeninfo['domid']
-
+ uuid1 = uuid.fromString(xeninfo['uuid'])
+ needs_reinitialising = False
+
dompath = GetDomainPath(domid)
if not dompath:
raise XendError('No domain path in store for existing '
@@ -151,12 +153,42 @@ def recreate(info, priv):
log.info("Recreating domain %d, UUID %s. at %s" %
(domid, xeninfo['uuid'], dompath))
- vmpath = xstransact.Read("/vm_path", str(domid))
+ # need to verify the path and uuid if not Domain-0
+ # if the required uuid and vm aren't set, then that means
+ # we need to recreate the dom with our own values
+ #
+ # NOTE: this is probably not desirable, really we should just
+ # abort or ignore, but there may be cases where xenstore's
+ # entry disappears (eg. xenstore-rm /)
+ #
+ try:
+ vmpath = xstransact.Read(dompath, "vm")
+ if not vmpath:
+ if not priv:
+ log.warn('/local/domain/%d/vm is missing. recreate is '
+ 'confused, trying our best to recover' % domid)
+ needs_reinitialising = True
+ raise XendError('reinit')
+
+ uuid2_str = xstransact.Read(vmpath, "uuid")
+ if not uuid2_str:
+ log.warn('%s/uuid/ is missing. recreate is confused, '
+ 'trying our best to recover' % vmpath)
+ needs_reinitialising = True
+ raise XendError('reinit')
+
+ uuid2 = uuid.fromString(uuid2_str)
+ if uuid1 != uuid2:
+ log.warn('UUID in /vm does not match the UUID in /dom/%d.'
+ 'Trying out best to recover' % domid)
+ needs_reinitialising = True
+ except XendError:
+ pass # our best shot at 'goto' in python :)
vm = XendDomainInfo(xeninfo, domid, dompath, augment = True, priv = priv,
vmpath = vmpath)
-
- if not vmpath:
+
+ if needs_reinitialising:
vm._recreateDom()
vm._removeVm()
vm._storeVmDetails()
@@ -1269,8 +1301,11 @@ class XendDomainInfo:
def _recreateDomFunc(self, t):
t.remove()
t.mkdir()
- t.set_permissions({'dom' : self.domid})
+ t.set_permissions({'dom' : self.domid, 'read' : True})
t.write('vm', self.vmpath)
+ for i in [ 'device', 'control', 'error' ]:
+ t.mkdir(i)
+ t.set_permissions(i, {'dom' : self.domid})
def _storeDomDetails(self):
to_store = {
@@ -1776,7 +1811,6 @@ class XendDomainInfo:
self._releaseDevices()
# Remove existing vm node in xenstore
self._removeVm()
- self._removeVmPath()
new_dom_info = self.info.copy()
new_dom_info['name_label'] = self.info['name_label']
new_dom_info['uuid'] = self.info['uuid']
@@ -2357,7 +2391,6 @@ class XendDomainInfo:
paths = self._prepare_phantom_paths()
- self._removeVmPath()
if self.dompath is not None:
try:
xc.domain_destroy_hook(self.domid)
@@ -2660,15 +2693,6 @@ class XendDomainInfo:
log.info("Dev still active but hit max loop timeout")
break
- def _storeVmPath(self):
- log.info("storeVmPath(%s) => %s", self.domid, self.vmpath)
- if self.domid is not None:
- xstransact.Write('/vm_path', str(self.domid), self.vmpath)
-
- def _removeVmPath(self):
- if self.domid is not None:
- xstransact.Remove('/vm_path/%s' % str(self.domid))
-
def _storeVmDetails(self):
to_store = {}
@@ -2693,7 +2717,6 @@ class XendDomainInfo:
self._writeVm(to_store)
self._setVmPermissions()
- self._storeVmPath()
def _setVmPermissions(self):
"""Allow the guest domain to read its UUID. We don't allow it to
diff -r ab19284c5070 -r 60937c4c5a67 tools/python/xen/xend/image.py
--- a/tools/python/xen/xend/image.py Wed Oct 01 14:07:17 2008 +0100
+++ b/tools/python/xen/xend/image.py Thu Oct 02 10:37:28 2008 +0100
@@ -418,7 +418,7 @@ class ImageHandler:
os.close(null)
os.close(logfd)
sentinel_write.close()
- self.vm.storeVm("image/device-model-pid", self.pid)
+ self.vm.storeDom("image/device-model-pid", self.pid)
log.info("device model pid: %d", self.pid)
# we would very much prefer not to have a thread here and instead
# have a callback but sadly we don't have Twisted in xend
@@ -502,7 +502,7 @@ class ImageHandler:
if fifo_fd >= 0:
self._openSentinel(sentinel_path_fifo)
os.close(fifo_fd)
- self.pid = self.vm._gatherVm(('image/device-model-pid', int))
+ self.pid = self.vm._gatherDom(('image/device-model-pid', int))
log.debug("%s device model rediscovered, pid %s sentinel fifo %s",
name, self.pid, sentinel_path_fifo)
self.sentinel_thread =
thread.start_new_thread(self._sentinel_watch,())
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