[bug-gnulib] Re: invalid assumption of m4/getcwd-path-max.m4

[Jim Meyering]

Thanks.
I've applied that (with copyright year and serial number updates)
to both coreutils and gnulib.

Eric Blake <address@hidden> wrote:
> According to Jim Meyering on 3/26/2005 7:17 AM:
>> Thanks for reporting that.
>> So the test program goes wrong on cygwin because of a
>> mkdir failure when the would-be cwd_len exceeds PATH_MAX.
> ...
>> If mkdir fails in a way (what errno value?) that cannot be confused
>> with e.g., disk full, then it should be easy to adjust the test program.
>> Just test for the combination of a too-large cwd_len and failed mkdir
>> with that errno value.
>
> Through cygwin 1.5.13, mkdir was failing with EINVAL, but since that does
> not match POSIX, I proposed a patch to cygwin to make it fail with
> ENAMETOOLONG in CVS (and the future cygwin 1.5.14).  I don't see any
> reason to check for EINVAL in this patch, as I already maintain a
> cygwin-specific patch to the cygwin distribution of coreutils; but there
> might be other systems where ENAMETOOLONG is worth checking, making the
> patch below a good idea for coreutils and gnulib.
>
>> Can you propose/test a patch?
>
> 2005-03-28  Eric Blake  <address@hidden>  (tiny change)
>
>       * getcwd-path-max.m4: Return success on systems such as cygwin
>       where no absolute path name can exceed PATH_MAX.

...
> Index: m4/getcwd-path-max.m4
> ===================================================================
> RCS file: /cvsroot/coreutils/coreutils/m4/getcwd-path-max.m4,v
> retrieving revision 1.15
> diff -u -p -r1.15 getcwd-path-max.m4
> --- m4/getcwd-path-max.m4     23 Jan 2005 09:07:57 -0000      1.15
> +++ m4/getcwd-path-max.m4     28 Mar 2005 20:05:56 -0000
> @@ -98,11 +98,15 @@ main (void)
>        char *c = NULL;
>  
>        cwd_len += DIR_NAME_SIZE;
> -      /* If mkdir or chdir fails, be pessimistic and consider that
> -      as a failure, too.  */
> +      /* If mkdir or chdir fails, it could be that this system cannot create
> +      any file with an absolute name longer than PATH_MAX, such as cygwin.
> +      If so, leave fail as 0, because the current working directory can't
> +      be too long for getcwd if it can't even be created.  For other
> +      errors, be pessimistic and consider that as a failure, too.  */
>        if (mkdir (DIR_NAME, S_IRWXU) < 0 || chdir (DIR_NAME) < 0)
>       {
> -       fail = 2;
> +       if (! (errno == ERANGE || is_ENAMETOOLONG (errno)))
> +         fail = 2;
>         break;
>       }
>