Re: [committed] Use structure to bubble up information about unterminated strings from c_strlen

[Christophe Lyon <christophe dot lyon at linaro dot org>]

On Sat, 29 Sep 2018 at 18:06, Jeff Law <law@redhat.com> wrote:
>
>
> This patch changes the NONSTR argument to c_strlen to instead be a
> little data structure c_strlen can populate with nuggets of information
> about the string.
>
> There's clearly a need for the decl related to the non-string argument.
> I see an immediate need for the length of a non-terminated string
> (c_strlen returns NULL for non-terminated strings).  I also see a need
> for the offset within the non-terminated strong as well.
>
> We only populate the structure when c_strlen encounters a non-terminated
> string.  One could argue we should always fill in the members.  Right
> now I think filling it in for unterminated cases makes the most sense,
> but I could be convinced otherwise.
>
> I won't be surprised if subsequent warnings from Martin need additional
> information about the string.  The idea here is we can add more elements
> to the structure without continually adding arguments to c_strlen.
>
> Bootstrapped in isolation as well as with Martin's patches for strnlen
> and sprintf checking.  Installing on the trunk.
>

Hi Jeff,

+             /* If TYPE is asking for a maximum, then use any
+                length (including the length of an unterminated
+                string) for VAL.  */
+             if (type == 2)
+               val = data.len;

It seems this part is dead-code, since the case type==2 is handled in
the "then" part of the "if" (this code is in the "else" part).

Since you added a comment, I suspect you explicitly tested it, though?

Christophe

> Jeff