Em Tue, Dec 10, 2013 at 01:18:01PM +0100, Ingo Molnar escreveu:
>
> * Adrian Hunter <[email protected]> wrote:
>
> > -void dso__set_short_name(struct dso *dso, const char *name)
> > +void dso__set_short_name(struct dso *dso, const char *name, bool
> > sname_alloc)
> > {
> > if (name == NULL)
> > return;
> > + if (dso->sname_alloc)
> > + free((char *)dso->short_name);
> > + dso->sname_alloc = sname_alloc;
>
> Calling the function option the same as the field name is asking for
> trouble - I'd suggest 'new_sname_alloc' for the parameter, or so.
>
> And I'd also remove the 'const' from struct dso::short_name, it
> probably does not help code generation, because 'dso' is passed in as
> const in all the non-lifetime methods anyway.
> That way the cast can be dropped from the free().
Not that simple, there are multiple places that pass a constant
short_name, for instance:
machine__get_kernel()
kernel = dso__kernel_findnew(machine, vmlinux_name,
"[kernel]", DSO_TYPE_KERNEL);
dso__set_short_name(dso, short_name);
So dso->short_name will point to "[kernel]", which is a const char *.
> Similar problems exist with the usage of 'short_name' - it overloads
> the field name which makes it somewhat confusing, and it's also
> sometimes inconsistently named, such as 'name' in
> dso__set_short_name().
>
> Ditto for 'long_name' handling.
>
> Also, the 'sname_alloc' name sucks, it does not make it obvious that
> it's related to 'short_name', hiding its true significance (and hiding
> the broken life time handling of the flag/pointer combo). I'd rename
> it to something more descriptive, like ->short_name_allocated - or I'd
> rename everything to 'sname'/'lname' naming for short/long names.
Ok, we can use rename it to short_name_alloc, like we have
short_name_len.
> Every time one runs into a crash like this it's a canary signal that
> cleanliness principles need hardening.
Hardening we go then!
> Thanks,
>
> Ingo
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