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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 12/27] tools/python: Libxl migration v2 infrastructure
Contains:
* Python implementation of the libxl migration v2 records
* Verification code for spec compliance
* Unit tests
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
tools/python/xen/migration/libxl.py | 188 +++++++++++++++++++++++++++++++++++
tools/python/xen/migration/tests.py | 13 +++
2 files changed, 201 insertions(+)
create mode 100644 tools/python/xen/migration/libxl.py
diff --git a/tools/python/xen/migration/libxl.py
b/tools/python/xen/migration/libxl.py
new file mode 100644
index 0000000..4e1f4f8
--- /dev/null
+++ b/tools/python/xen/migration/libxl.py
@@ -0,0 +1,188 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+Libxl Migration v2 streams
+
+Record structures as per docs/specs/libxl-migration-stream.pandoc, and
+verification routines.
+"""
+
+import sys
+
+from struct import calcsize, unpack
+from xen.migration.verify import StreamError, RecordError, VerifyBase
+from xen.migration.libxc import VerifyLibxc
+
+# Header
+HDR_FORMAT = "!QII"
+
+HDR_IDENT = 0x4c6962786c466d74 # "LibxlFmt" in ASCII
+HDR_VERSION = 2
+
+HDR_OPT_BIT_ENDIAN = 0
+HDR_OPT_BIT_LEGACY = 1
+
+HDR_OPT_LE = (0 << HDR_OPT_BIT_ENDIAN)
+HDR_OPT_BE = (1 << HDR_OPT_BIT_ENDIAN)
+HDR_OPT_LEGACY = (1 << HDR_OPT_BIT_LEGACY)
+
+HDR_OPT_RESZ_MASK = 0xfffc
+
+# Records
+RH_FORMAT = "II"
+
+REC_TYPE_end = 0x00000000
+REC_TYPE_libxc_context = 0x00000001
+REC_TYPE_xenstore_data = 0x00000002
+REC_TYPE_emulator_context = 0x00000003
+
+rec_type_to_str = {
+ REC_TYPE_end : "End",
+ REC_TYPE_libxc_context : "Libxc context",
+ REC_TYPE_xenstore_data : "Xenstore data",
+ REC_TYPE_emulator_context : "Emulator context",
+}
+
+# emulator_context
+EMULATOR_CONTEXT_FORMAT = "II"
+
+EMULATOR_ID_unknown = 0x00000000
+EMULATOR_ID_qemu_trad = 0x00000001
+EMULATOR_ID_qemu_upstream = 0x00000002
+
+emulator_id_to_str = {
+ EMULATOR_ID_unknown : "Unknown",
+ EMULATOR_ID_qemu_trad : "Qemu Traditional",
+ EMULATOR_ID_qemu_upstream : "Qemu Upstream",
+}
+
+
+#
+# libxl format
+#
+
+LIBXL_QEMU_SIGNATURE = "DeviceModelRecord0002"
+LIBXL_QEMU_RECORD_HDR = "=%dsI" % (len(LIBXL_QEMU_SIGNATURE), )
+
+class VerifyLibxl(VerifyBase):
+ """ Verify a Libxl v2 stream """
+
+ def __init__(self, info, read):
+ VerifyBase.__init__(self, info, read)
+
+
+ def verify(self):
+ """ Verity a libxl stream """
+
+ self.verify_hdr()
+
+ while self.verify_record() != REC_TYPE_end:
+ pass
+
+
+ def verify_hdr(self):
+ """ Verify a Header """
+ ident, version, options = self.unpack_exact(HDR_FORMAT)
+
+ if ident != HDR_IDENT:
+ raise StreamError("Bad image id: Expected 0x%x, got 0x%x"
+ % (HDR_IDENT, ident))
+
+ if version != HDR_VERSION:
+ raise StreamError("Unknown image version: Expected %d, got %d"
+ % (HDR_VERSION, version))
+
+ if options & HDR_OPT_RESZ_MASK:
+ raise StreamError("Reserved bits set in image options field: 0x%x"
+ % (options & HDR_OPT_RESZ_MASK))
+
+ if ( (sys.byteorder == "little") and
+ ((options & HDR_OPT_BIT_ENDIAN) != HDR_OPT_LE) ):
+ raise StreamError(
+ "Stream is not native endianess - unable to validate")
+
+ endian = ["little", "big"][options & HDR_OPT_LE]
+
+ if options & HDR_OPT_LEGACY:
+ self.info("Libxl Header: %s endian, legacy converted" % (endian, ))
+ else:
+ self.info("Libxl Header: %s endian" % (endian, ))
+
+
+ def verify_record(self):
+ """ Verify an individual record """
+ rtype, length = self.unpack_exact(RH_FORMAT)
+
+ if rtype not in rec_type_to_str:
+ raise StreamError("Unrecognised record type %x" % (rtype, ))
+
+ self.info("Libxl Record: %s, length %d"
+ % (rec_type_to_str[rtype], length))
+
+ contentsz = (length + 7) & ~7
+ content = self.rdexact(contentsz)
+
+ padding = content[length:]
+ if padding != "\x00" * len(padding):
+ raise StreamError("Padding containing non0 bytes found")
+
+ if rtype not in record_verifiers:
+ raise RuntimeError("No verification function for libxl record '%s'"
+ % rec_type_to_str[rtype])
+ else:
+ record_verifiers[rtype](self, content[:length])
+
+ return rtype
+
+
+ def verify_record_end(self, content):
+ """ End record """
+
+ if len(content) != 0:
+ raise RecordError("End record with non-zero length")
+
+
+ def verify_record_libxc_context(self, content):
+ """ Libxc context record """
+
+ if len(content) != 0:
+ raise RecordError("Libxc context record with non-zero length")
+
+ # Verify the libxc stream, as we can't seek forwards through it
+ VerifyLibxc(self.info, self.read).verify()
+
+
+ def verify_record_xenstore_data(self, content):
+ """ Xenstore Data record """
+
+ if len(content) == 0:
+ raise RecordError("Xenstore data record with zero length")
+
+
+ def verify_record_emulator_context(self, content):
+ """ Emulator Context record """
+ minsz = calcsize(EMULATOR_CONTEXT_FORMAT)
+
+ if len(content) < minsz:
+ raise RecordError("Length must be at least %d bytes, got %d"
+ % (minsz, len(content)))
+
+ emu_id, emu_idx = unpack(EMULATOR_CONTEXT_FORMAT, content[:minsz])
+
+ if emu_id not in emulator_id_to_str:
+ raise RecordError("Unrecognised emulator id 0x%x" % (emu_id, ))
+
+ self.info(" Index %d, type %s" % (emu_idx,
emulator_id_to_str[emu_id]))
+
+
+record_verifiers = {
+ REC_TYPE_end:
+ VerifyLibxl.verify_record_end,
+ REC_TYPE_libxc_context:
+ VerifyLibxl.verify_record_libxc_context,
+ REC_TYPE_xenstore_data:
+ VerifyLibxl.verify_record_xenstore_data,
+ REC_TYPE_emulator_context:
+ VerifyLibxl.verify_record_emulator_context,
+}
diff --git a/tools/python/xen/migration/tests.py
b/tools/python/xen/migration/tests.py
index 3e97268..91044cd 100644
--- a/tools/python/xen/migration/tests.py
+++ b/tools/python/xen/migration/tests.py
@@ -30,10 +30,23 @@ class TestLibxc(unittest.TestCase):
self.assertEqual(calcsize(fmt), sz)
+class TestLibxl(unittest.TestCase):
+
+ def test_format_sizes(self):
+
+ for fmt, sz in ( (libxl.HDR_FORMAT, 16),
+ (libxl.RH_FORMAT, 8),
+
+ (libxl.EMULATOR_CONTEXT_FORMAT, 8),
+ ):
+ self.assertEqual(calcsize(fmt), sz)
+
+
def test_suite():
suite = unittest.TestSuite()
suite.addTest(unittest.makeSuite(TestLibxc))
+ suite.addTest(unittest.makeSuite(TestLibxl))
return suite
--
1.7.10.4
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