From: René Scharfe <l.s.r@web.de>
Date: Wed, 19 Apr 2017 14:03:19 GMT
Subject: Re: [PATCH v3 1/2] use HOST_NAME_MAX to size buffers for gethostname(2)
Message-ID: <269cbe1c-d10a-7022-1977-2128d59aebb3@web.de>
In-Reply-To: <20170419012824.GA28740@aiede.svl.corp.google.com>

Am 19.04.2017 um 03:28 schrieb Jonathan Nieder:
>> From: René Scharfe <l.s.r@web.de>
>>
>> POSIX limits the length of host names to HOST_NAME_MAX.  Export the
>> fallback definition from daemon.c and use this constant to make all
>> buffers used with gethostname(2) big enough for any possible result
>> and a terminating NUL.
> 
> Since some platforms do not define HOST_NAME_MAX and we provide a
> fallback, this is not actually big enough for any possible result.
> For example, the Hurd allows arbitrarily long hostnames.

Interesting.  No limits, eh?  They suggest to allocate memory
dynamically [1].  Perhaps we should import their xgethostname() (which
grows a buffer as needed), or implement a strbuf_add_hostname()?

René


https://www.gnu.org/software/hurd/hurd/porting/guidelines.html#MAXHOSTNAMELEN_tt_