Re: Bug#933015: libssh FTBFS on hurd: unconditional usage of PATH_MAX

[Guillem Jover <guillem@debian.org>]

Hi!

On Thu, 2019-07-25 at 20:36:31 +0200, Paul Sonnenschein wrote:
> Package: src:libssh
> Severity: Important
> Version: 0.9.0-1
> Tags: patch
> User: debian-hurd@lists.debian.org
> Usertags: hurd
> X-Debbugs-CC: debian-hurd@lists.debian.org

> the package libssh fails to build from source on hurd-i386 in sid due
> to an unconditional use of PATH_MAX, which the Hurd does not provide.

> --- a/tests/torture.c
> +++ b/tests/torture.c
> @@ -1029,17 +1029,25 @@ char *torture_get_current_working_dir(void)
>  
>      char *cwd = NULL;
>      char *result = NULL;
> +    size_t path_max;
> +
> +#ifdef PATH_MAX
> +    path_max = PATH_MAX;
> +#else
> +    path_max = 4095;
> +#endif /* PATH_MAX undefined */

I'd probably just unconditionally set the value and avoid PATH_MAX
completely.

> +    for ( ; result == NULL; path_max *= 2) {
> +        cwd = (char *)realloc(cwd, path_max + 1);
> +        if (cwd == NULL) {
> +            goto end;
> +        }
>  
> -    cwd = (char *)malloc(PATH_MAX + 1);
> -    if (cwd == NULL) {
> -        goto end;
> -    }
> -
> -    result = getcwd(cwd, PATH_MAX);
> +        result = getcwd(cwd, path_max);

JFTR, there's also the getcwd(NULL, 0) extension which is supported by
GNU and BSD systems, at least. Or the explicit GNU specific function
get_current_dir_name(), But that would need some kind of configuration
check, and some fallback code anyway.

> -    if (result == NULL) {
> -        SAFE_FREE(cwd);
> -        goto end;
> +        if (result == NULL && errno != ERANGE) {
> +            SAFE_FREE(cwd);
> +            goto end;
> +        }
>      }
>  
>  end:

Thanks,
Guillem