From dd54a15a7f3964addae3eef9a4eef30d22690b97 Mon Sep 17 00:00:00 2001 From: Rick Harris Date: Tue, 24 Jul 2012 18:22:41 +0000 Subject: [PATCH] Xen: Validate VHD footer timestamps. This is a sanity check to ensure the footer timestamps on a VHD are reasonable (e.g. not in the future). This condition can occur if the local time for the source and destination machines in a migration are not in agreement, requiring an adjustment to /etc/localtime and/or NTP reconfiguration. Without this check there is a risk of importing a corrupt VHD into the SR causing the entire SR to become corrupted. Change-Id: I17228e50d6f54632f3bfc32a682e511f876517ec --- .../xenapi/etc/xapi.d/plugins/utils.py | 24 +++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/plugins/xenserver/xenapi/etc/xapi.d/plugins/utils.py b/plugins/xenserver/xenapi/etc/xapi.d/plugins/utils.py index 23165bba187e..bd92866581f7 100644 --- a/plugins/xenserver/xenapi/etc/xapi.d/plugins/utils.py +++ b/plugins/xenserver/xenapi/etc/xapi.d/plugins/utils.py @@ -156,6 +156,28 @@ def _assert_vhd_not_hidden(path): locals()) +def _validate_footer_timestamp(vdi_path): + """ + This check ensures that the timestamps listed in the VHD footer aren't in + the future. This can occur during a migration if the clocks on the the two + Dom0's are out-of-sync. This would corrupt the SR if it were imported, so + generate an exception to bail. + """ + check_cmd = "vhd-util check -n %(vdi_path)s -p" % locals() + check_proc = make_subprocess(check_cmd, stdout=True, stderr=True) + out, err = finish_subprocess( + check_proc, check_cmd, ok_exit_codes=[0, 22]) + first_line = out.splitlines()[0].strip() + + if 'primary footer invalid' in first_line: + raise Exception("VDI '%(vdi_path)s' has timestamp in the future," + " ensure source and destination host machines have" + " time set correctly" % locals()) + elif check_proc.returncode != 0: + raise Exception("Unexpected output '%(out)s' from vhd-util" % + locals()) + + def _validate_vdi_chain(vdi_path): """ This check ensures that the parent pointers on the VHDs are valid @@ -169,6 +191,7 @@ def _validate_vdi_chain(vdi_path): out, err = finish_subprocess( query_proc, query_cmd, ok_exit_codes=[0, 22]) first_line = out.splitlines()[0].strip() + if first_line.endswith(".vhd"): return first_line elif 'has no parent' in first_line: @@ -182,6 +205,7 @@ def _validate_vdi_chain(vdi_path): cur_path = vdi_path while cur_path: + _validate_footer_timestamp(cur_path) cur_path = get_parent_path(cur_path)