Re: [PATCH v2] smbios: Add a --linux argument to apply linux modalias-like filtering

[Julian Andres Klode]

On Tue, Mar 03, 2020 at 05:44:54PM +0100, Daniel Kiper wrote:
> On Tue, Mar 03, 2020 at 04:06:34PM +0100, Julian Andres Klode wrote:
> > @@ -261,6 +279,7 @@ grub_cmd_smbios (grub_extcmd_context_t ctxt,
> >
> >    const grub_uint8_t *structure;
> >    const char *value;
> > +  char *modified_value = NULL;
> >    grub_int32_t option;
> >    grub_int8_t field_type = -1;
> >    grub_uint8_t i;
> > @@ -334,12 +353,17 @@ grub_cmd_smbios (grub_extcmd_context_t ctxt,
> >      return grub_error (GRUB_ERR_IO,
> >                         N_("failed to retrieve the structure field"));
> >
> > +  if (state[LINUX_OPT].set)
> > +    value = modified_value = linux_string (value);
> > +
> >    /* Store or print the formatted value. */
> >    if (state[SETTER_OPT].set)
> >      grub_env_set (state[SETTER_OPT].arg, value);
> >    else
> >      grub_printf ("%s\n", value);
> >
> > +  grub_free(modified_value);
> 
> I am not sure why we need modified_value if you free it immediately here...

Because `value` is `const char *` that might point to static buffers or
other buffers, so we need to store this dynamically allocated string
somewhere else we can free later.

I guess we could also store the buffer statically with a size and realloc
it if it's too small, thus reusing it and not having to free it, but this
approach seemed slightly easier.

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