Re: NET_WM_PID is broken (was: NET_WM_PID and client leader)

[Havoc Pennington <hp redhat com>]

Hi,

Any comments on this or should I commit it?

Havoc

Havoc Pennington <hp redhat com> writes:
> Hi,
> 
> Sorry for the slow reply; I was just reminded that I needed to reply
> by the traffic on this list. ;-)
> 
> I somewhat modified your proposed wm-spec.sgml patch and propose the
> following patch instead.
> 
> I basically made two changes:
>  - I think you meant WM_CLIENT_MACHINE instead of WM_CLIENT_NAME in 
>    a couple places?
>  - I don't think the spec should require a specific implementation;
>    instead I wrote that the "fully-qualified domain name" must be
>    used.
> 
> I think the FQDN is a well-understood concept, e.g. here is the
> definition from the GNU libc manual:
>  
> 
>    In DNS, the full host name is properly called the FQDN (Fully
>    Qualified Domain Name) and consists of the hostname, then a period,
>    then the domain name.  The domain name itself usually has multiple
>    components separated by periods.  So for example, a system's
>    hostname may be `chicken' and its domain name might be
>    `ai.mit.edu', so its FQDN (which is its host name) is
>    `chicken.ai.mit.edu'.
> 
> Then I moved your text about gethostname() and uname() to
> implementation notes.
> 
> I think this is more appropriate for a spec, we are just supposed to
> specify behavior, not what you have to do to get that behavior. If
> clients have some better way to get FQDN then they should feel free to
> do so.
> 
> Havoc
> 
> 
> 
> Index: wm-spec.sgml
> ===================================================================
> RCS file: /home/freedesktop/wm-spec/wm-spec.sgml,v
> retrieving revision 1.12
> diff -u -p -u -r1.12 wm-spec.sgml
> --- wm-spec.sgml	2001/05/09 02:55:08	1.12
> +++ wm-spec.sgml	2001/08/16 12:31:17
> @@ -788,6 +788,14 @@ window.  This MAY be used by the Window 
>  respond to the _NET_WM_PING protocol.
>  		</para>
>  	<para>
> +If _NET_WM_PID is set, the ICCCM-specified property WM_CLIENT_MACHINE
> +MUST also be set.  While the ICCCM only requests that WM_CLIENT_MACHINE is set
> +<quote> to a string that forms the name of the machine running the client as
> +seen from the machine running the server</quote> conformance to this
> +specification requires that WM_CLIENT_MACHINE be set to the fully-qualified domain 
> +name of the client's host.
> +	</para>
> +	<para>
>  See also the implementation notes on <link linkend="KILLINGWINDOWS">killing hung processes</link>.
>  	</para>
>  	</sect2>
> @@ -1092,8 +1100,47 @@ was the frame for this window.
>  	</sect2>
>  	<sect2 id="KILLINGWINDOWS">
>  		<title>Killing Hung Processes</title>
> +		<para>
> +If processes fail to respond to the _NET_WM_PING protocol _NET_WM_PID may be
> +used in combination with the ICCCM specified WM_CLIENT_MACHINE to 
> +attempt to kill a process.
> +		</para>
> +
> +		<para>
> +WM_CLIENT_MACHINE must be set to the fully-qualified domain name of the client's
> +host. This would normally be retrieved using gethostname(2).  When gethostname()
> +is not available on the client's platform implementors may use the value of the
> +nodename field of struct utsname as returned by uname(2).  An example of how to
> +retrieve a value for WM_CLIENT_MACHINE:
> +		</para>
>  		<para>
> -If processes fail to respond to the _NET_WM_PING protocol _NET_WM_PID may be used in combination with the ICCCM specified WM_CLIENT_MACHINE(STRING) to attempt to kill a process. 
> +	<programlisting><![CDATA[
> +int net_get_hostname (char *buf, size_t maxlen)
> +{
> +#ifdef HAVE_GETHOSTNAME
> +	if (buf == NULL) return 0;
> +
> +	gethostname (buf, maxlen);
> +	buf [maxlen - 1] = '\0';
> +
> +	return strlen(buf);
> +#else
> +	struct utsname name;
> +	size_t len;
> +
> +	if (buf == NULL) return 0;
> +
> +	uname (&name);
> +	len = strlen (name.nodename);
> +
> +	if (len >= maxlen) len = maxlen - 1;
> +	strncpy (buf, name.nodename, len);
> +	buf[len] = '\0';
> +
> +	return len;
> +#endif
> +}
> +]]></programlisting>
>  		</para>
>  	</sect2>
>  	</Sect1>
> @@ -1166,6 +1213,17 @@ OR OTHER DEALINGS IN THE SOFTWARE.  
>  	</sect1>
>    <Sect1>
>      <title>Change history</title>
> + 	    <sect2>
> + 		<title>Changes since 1.1</title>
> + 		<itemizedlist>
> + 			<listitem><para>
> + Changed WM_CLIENT_NAME(STRING) from suggested to required for _NET_WM_PID.
> + 			</para></listitem>
> + 			<listitem><para>
> + Specification and sample code for the content of WM_CLIENT_NAME(STRING).
> + 			</para></listitem>
> + 	</itemizedlist>
> + 	</sect2>
>      <sect2>
>  		<title>Changes since 1.0</title>
>  		<itemizedlist>
> 
> 
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