[PATCH] GLX: Avoid a crash if we ever end up trying to use glapi_noop_table

[Jon TURNEY]

Brian Paul wrote:
> 
> I'm in favor of this patch.  But I'm not such which xserver branch(es) 
> it should be applied to.  Can someone clue me in?

Applied to git master as commit 	c745db1674c3cb55249c9eb6e74939b74c42409c.

I'm not sure if I've understood your question correctly, but I think you could 
go to http://www.x.org/wiki/Server16Branch if you wished to nominate it for 
that branch (although I have a hard time convincing myself it's worthy)

> Jon TURNEY wrote:
>> I'm not sure if this is patch-worthy or not, but whilst getting GLX to 
>> work again on Cygwin/X I came across this...
>>
>> If the GL dispatch table pointer points to glapi_noop_table, (due to 
>> some kind of terrible failure during GL initialization), running 
>> glxinfo for e.g. will crash the X server, as DoGetString(GL_VERSION) 
>> tries to do atof() on the null pointer returned by the noop dispatch 
>> function.
>>
>> Given that all that noop dispatch table stuff is in there, I guess 
>> it's preferable that it doesn't crash in that case.
>>
>>
>>
>> ------------------------------------------------------------------------
>>
>> From 2e9ddcdaa1890204ec69ba6848cb1c49d5b85ef3 Mon Sep 17 00:00:00 2001
>> Message-Id: 
>> <2e9ddcdaa1890204ec69ba6848cb1c49d5b85ef3.1231288719.git.jon.turney at dronecode.org.uk> 
>>
>> In-Reply-To: <cover.1231288706.git.jon.turney at dronecode.org.uk>
>> References: <cover.1231288706.git.jon.turney at dronecode.org.uk>
>> From: Jon TURNEY <jon.turney at dronecode.org.uk>
>> Date: Mon, 5 Jan 2009 13:52:45 +0000
>> Subject: [PATCH 18/22] GLX: Avoid a crash when we have an 
>> uninitialized GL context
>>
>> If the GL dispatch table pointer points to glapi_noop_table,
>> (due to some kind of GL initialization failure), DoGetString(GL_VERSION)
>> (for example as invoked by glxinfo) will crash as it tries to
>> do atof() on the null pointer returned by the noop dispatch function
>>
>> Signed-off-by: Jon TURNEY <jon.turney at dronecode.org.uk>
>> ---
>>  glx/single2.c |    3 +++
>>  1 files changed, 3 insertions(+), 0 deletions(-)
>>
>> diff --git a/glx/single2.c b/glx/single2.c
>> index 0ca808c..50a59ed 100644
>> --- a/glx/single2.c
>> +++ b/glx/single2.c
>> @@ -335,6 +335,9 @@ int DoGetString(__GLXclientState *cl, GLbyte *pc, 
>> GLboolean need_swap)
>>      string = (const char *) CALL_GetString( GET_DISPATCH(), (name) );
>>      client = cl->client;
>>  
>> +    if (string == NULL)
>> +      string = "";
>> +
>>      /*
>>      ** Restrict extensions to those that are supported by both the
>>      ** implementation and the connection.  That is, return the