Received-SPF: pass (google.com: best guess record for domain of linux-nfs-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH 1/3] mount: fix compilation if __GLIBC__ is not defined
To:     Patrick Steinhardt <ps@pks.im>, linux-nfs@vger.kernel.org
References: <6de0089348765e60bcdf59ef5813d7bb631c967f.1566805721.git.ps@pks.im>
From:   Steve Dickson <SteveD@RedHat.com>
Message-ID: <8a22b4ac-ada6-83b1-361a-62b74f957878@RedHat.com>
Date:   Mon, 26 Aug 2019 14:03:04 -0400
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.8.0
MIME-Version: 1.0
In-Reply-To: <6de0089348765e60bcdf59ef5813d7bb631c967f.1566805721.git.ps@pks.im>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-nfs-owner@vger.kernel.org
Precedence: bulk


On 8/26/19 3:48 AM, Patrick Steinhardt wrote:
> As glibc versions before v2.24 couldn't safely include <linux/in6.h>,
> commit 8af595b7 (mount: support compiling with old glibc, 2017-07-26)
> introduced some preprocessor checks to special-case such old versions.
> While there is a check whether __GLIBC__ is defined at all, it only
> applies to the first comparison `__GLIBC__ < 2`, but doesn't apply to
> the second check due to operator precedence. Thus the preprocessor may
> use an undefined value and thus generate an error if __GLIBC__ is not
> defined.
> 
> Fix the issue by wrapping the version check in braces.
> 
> Signed-off-by: Patrick Steinhardt <ps@pks.im>
Commited....

steved.
> ---
>  utils/mount/network.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/utils/mount/network.c b/utils/mount/network.c
> index e166a823..6ac913d9 100644
> --- a/utils/mount/network.c
> +++ b/utils/mount/network.c
> @@ -39,7 +39,7 @@
>  #include <sys/socket.h>
>  #include <sys/wait.h>
>  #include <sys/stat.h>
> -#if defined(__GLIBC__) && (__GLIBC__ < 2) || (__GLIBC__ == 2 && __GLIBC_MINOR__ < 24)
> +#if defined(__GLIBC__) && ((__GLIBC__ < 2) || (__GLIBC__ == 2 && __GLIBC_MINOR__ < 24))
>  /* Cannot safely include linux/in6.h in old glibc, so hardcode the needed values */
>  # define IPV6_PREFER_SRC_PUBLIC 2
>  # define IPV6_ADDR_PREFERENCES 72
>