Re: [Xen-devel] PATCH: fix xenstore doc

[Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>]

Tristan Gingold writes (untabified):
>  READ                 <path>|                 <value|>
> -WRITE                <path>|<value|>
> +WRITE                <path>|<value>

This change is not correct.  The document was correct beforehand.  In
xenstore.txt the notation  <value|>  is used to indicate that the
value _may_ contain nuls, not that it will contain one trailing nul.

>From the introduction, which explains the notation:

 <foo|>         Binary data (which may contain zero or more nul bytes)

And it is clearly stated that the use of trailing nuls is not
encouraged:

 While xenstore and most tools and APIs are capable of dealing with
 arbitrary binary data as values, this should generally be avoided.
 Data should generally be human-readable for ease of management and
 debugging; xenstore is not a high-performance facility and should be
 used only for small amounts of control plane data.  Therefore xenstore
 values should normally be 7-bit ASCII text strings containing bytes
 0x20..0x7f only, and should not contain a trailing nul byte.  (The
 APIs used for accessing xenstore generally add a nul when reading, for
 the caller's convenience.)

Ian.

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