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Re: [PATCH v3 1/2] use HOST_NAME_MAX to size buffers for gethostname(2)

From
René Scharfe <l.s.r@web.de>
Date
Apr 19, 2017, 14:03 UTC
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:
Show 10 quoted lines
>> 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_
Previous: Junio C HamanoNext: René Scharfe
Message 11 of 18 in “gethostbyname fixes”
  1. 0/2 gethostbyname fixesDavid Turner, Apr 18, 2017
  2. 2/2 xgethostname: handle long hostnamesDavid Turner, Apr 18, 2017
  3. Jonathan NiederApr 19, 2017
  4. Junio C HamanoApr 19, 2017
  5. David TurnerApr 19, 2017
  6. René ScharfeApr 19, 2017
  7. Junio C HamanoApr 19, 2017
  8. 1/2 use HOST_NAME_MAX to size buffers for gethostname(2)David Turner, Apr 18, 2017
  9. Jonathan NiederApr 19, 2017
  10. Junio C HamanoApr 19, 2017
  11. René ScharfeApr 19, 2017
  12. René ScharfeApr 19, 2017
  13. David TurnerApr 19, 2017
  14. Torsten BögershausenApr 19, 2017
  15. René ScharfeApr 19, 2017
  16. Torsten BögershausenApr 20, 2017
  17. René ScharfeApr 20, 2017
  18. Torsten BögershausenApr 21, 2017

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