| Message ID | 20210701095635.15648-6-olaf@aepfle.de (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | leftover from 2020 | expand |
On 01/07/2021 10:56, Olaf Hering wrote: > diff --git a/tools/python/scripts/convert-legacy-stream b/tools/python/scripts/convert-legacy-stream > index 66ee3d2f5d..9003ac4f6d 100755 > --- a/tools/python/scripts/convert-legacy-stream > +++ b/tools/python/scripts/convert-legacy-stream > @@ -336,20 +336,21 @@ def read_libxl_toolstack(vm, data): > if len(data) < namelen: > raise StreamError("Remaining data too short for physmap name") > > - name = data[:namelen] > + c_string = data[:namelen] > data = data[namelen:] > > # Strip padding off the end of name > if twidth == 64: > - name = name[:-4] > + c_string = c_string[:-4] > > - if name[-1] != b'\x00': > + name, nil = unpack("={0}sB".format(len(c_string) - 1), c_string) This is rather invasive. How about simply: diff --git a/tools/python/scripts/convert-legacy-stream b/tools/python/scripts/convert-legacy-stream index ca93a93848ec..d4ae94c02f21 100755 --- a/tools/python/scripts/convert-legacy-stream +++ b/tools/python/scripts/convert-legacy-stream @@ -342,7 +342,7 @@ def read_libxl_toolstack(vm, data): if twidth == 64: name = name[:-4] - if name[-1] != b'\x00': + if bytearray(name)[-1] != 0: raise StreamError("physmap name not NUL terminated") root = b"physmap/%x" % (phys, ) which is rather more contained, and looks to work from Py2.6 and later? ~Andrew
diff --git a/tools/python/scripts/convert-legacy-stream b/tools/python/scripts/convert-legacy-stream index 66ee3d2f5d..9003ac4f6d 100755 --- a/tools/python/scripts/convert-legacy-stream +++ b/tools/python/scripts/convert-legacy-stream @@ -336,20 +336,21 @@ def read_libxl_toolstack(vm, data): if len(data) < namelen: raise StreamError("Remaining data too short for physmap name") - name = data[:namelen] + c_string = data[:namelen] data = data[namelen:] # Strip padding off the end of name if twidth == 64: - name = name[:-4] + c_string = c_string[:-4] - if name[-1] != b'\x00': + name, nil = unpack("={0}sB".format(len(c_string) - 1), c_string) + if nil != 0: raise StreamError("physmap name not NUL terminated") root = b"physmap/%x" % (phys, ) kv = [root + b"/start_addr", b"%x" % (start, ), root + b"/size", b"%x" % (size, ), - root + b"/name", name[:-1]] + root + b"/name", name] for key, val in zip(kv[0::2], kv[1::2]): info(" '%s' = '%s'" % (key.decode(), val.decode()))
The trailing member name[] in libxl__physmap_info is written as a cstring into the stream. The current code does a sanity check if the last byte is zero. This attempt fails with python3.4 because name[-1] returns a type int. As a result the comparison with byte(\00) fails: File "/usr/lib/xen/bin/convert-legacy-stream", line 347, in read_libxl_toolstack raise StreamError("physmap name not NUL terminated") StreamError: physmap name not NUL terminated To handle both python variants the cstring is unpacked into the actual string and the trailing nil. Signed-off-by: Olaf Hering <olaf@aepfle.de> --- tools/python/scripts/convert-legacy-stream | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)