[PATCH] fixincludes: fix portability issues about getcwd() [PR21283, PR80047]

[Bruce Korb]

If you are going to be excruciatingly, painfully correct, free() is 
going to be unhappy about freeing a static string in the event getcwd() 
fails for some inexplicable reason. I'd replace the free() + return with 
a call to exit. Maybe even:

    if (VERY_UNLIKELY (access (pz_curr_file, R_OK) != 0)) abort()

On 11/11/21 8:33 AM, Xi Ruoyao wrote:
> ---
>   fixincludes/fixincl.c | 13 +++++++++++--
>   1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/fixincludes/fixincl.c b/fixincludes/fixincl.c
> index 6dba2f6e830..1580c67efec 100644
> --- a/fixincludes/fixincl.c
> +++ b/fixincludes/fixincl.c
> @@ -1353,9 +1353,18 @@ process (void)
>     if (access (pz_curr_file, R_OK) != 0)
>       {
>         int erno = errno;
> +      char *buf = NULL;
> +      const char *cwd = NULL;
> +      for (size_t size = 256; !cwd; size += size)
> +	{
> +	  buf = xrealloc (buf, size);
> +	  cwd = getcwd (buf, size);
> +	  if (!cwd && errno != ERANGE)
> +	    cwd = "the working directory";
> +	}
>         fprintf (stderr, "Cannot access %s from %s\n\terror %d (%s)\n",
> -               pz_curr_file, getcwd ((char *) NULL, MAXPATHLEN),
> -               erno, xstrerror (erno));
> +	       pz_curr_file, cwd, erno, xstrerror (erno));
> + free (buf); return;
>       }
>