[PATCH] support_become_root: Don't fail when /proc/<pid/setgroups is missing

[Florian Weimer]

On 11/18/2017 02:41 AM, Christian Brauner wrote:
> The requirement to write "deny" to /proc/<pid>/setgroups for a given user
> namespace before being able to write a gid mapping was introduced in Linux 3.19.
> Before that this requirement including the file did not exist. So don't fail
> when errno == ENOENT.

The substance of the patch is fine, but please restrict line length to 
79 characters (not 80 or more):

> +	* support/support_become_root.c (setup_uid_gid_mapping): Don't fail when

> +  /* Linux 3.19 introduced the setgroups file. We need write "deny" to this file

> +        FAIL_EXIT1 ("open64 (\"/proc/self/setgroups\", 0x%x, 0%o): %m", O_WRONLY, 0);

Please also use two spaces after the period at the end of a sentence, 
including the period before the closing comment marker, */.  This 
affects three sentences in two comments.

Thanks,
Florian