Re: [PING][PATCH v2] Remove check for NULL buffer passed to `ptsname_r'

[Arjun Shankar <arjun dot is at lostca dot se>]

On Wed, Jun 07, 2017 at 09:39:40AM -0400, Zack Weinberg wrote:
> > `ptsname_r' is declared in stdlib.h to only accept a `nonnull'
> > second argument and therefore GCC may choose to make optimizations
> > based on the assumption that this argument is NULL. This means
> > that potentially, GCC can optimize away the NULL check at some
> > point in the future. Since this is a programming interface, we
> > might as well remove the NULL check ourselves.
> >
> > This also warrants a change to the `ptsname_r' manual page that
> > must be submitted to the corresponding mailing list.
> 
> Is this function documented in our manual (manual/*.texi)? If so,
> please update that.

The function is documented, but there is no reference to EINVAL and no
hint that a NULL buf is handled in any way. Here is the relevant text
(source is in manual/terminal.texi):

>  -- Function: int ptsname_r (int FILEDES, char *BUF, size_t LEN)
>      Preliminary: | MT-Safe | AS-Unsafe heap/bsd | AC-Unsafe mem fd |
>      *Note POSIX Safety Concepts::.
> 
>      The ptsname_r function is similar to the ptsname function
>      except that it places its result into the user-specified buffer
>      starting at BUF with length LEN.
> 
>      This function is a GNU extension.

Given this, I propose that we leave the this section unchanged. Instead, I
will propose a change to the man-pages project where `man ptsname_r'
documents this (now unhandled) error condition:

> EINVAL (ptsname_r() only) buf is NULL.

...once I commit this change.

Does the above sound like a reasonable course of action?

> OK with that change.  I don't think we need a copyright assignment for
> a change that deletes seven lines of code and adds none.

Even otherwise, I have an assignment on file, and I recently got commit
access in git :)

Cheers,
Arjun