host name length

[Ulrich Drepper]

POSIX nowadays contains

  _POSIX_HOST_NAME_MAX
and
  HOST_NAME_MAX

for programs to use to learn about the maximum host name length which is
allowed.  _POSIX_HOST_NAME_MAX is the standard-required minimum maximum
and the value must be 256.

The problem is that HOST_NAME_MAX currently is defined as 64, as defined
by __NET_UTS_LEN in <linux/utsname.h>.  I.e., we have HOST_NAME_MAX as
smaller than the minimum maximum which is obviously not POSIX compliant.

Now, we can simply ignore the problem or do something about it and
introduce a third version of the utsname structure with sufficiently big
nodename field.

Many OSes used small values before but 256 was chosen as a minimum
maximum and some OSes were changed since host names longer than 64 chars
indeed do exist.  I wonder why this never has been brought to the
attention.  Or were people happy enough with truncated host names?


Anyway, is there interest in getting this changed?

-- 
â Ulrich Drepper â Red Hat, Inc. â 444 Castro St â Mountain View, CA â
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