maybe a smaller HOST_NAME_MAX?

maybe a smaller HOST_NAME_MAX?

[He X]

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in limits.h, glibc defines it as 64, musl has a valueof 255.

according a man page:
http://man7.org/linux/man-pages/man2/gethostname.2.html. HOST_NAME_MAX is
defined as 64 since linux 1.0. include/uapi/asm-generic/param.h could
verify that.

as musl targeted on linux-based devices, i think it makes sense to use a
smaller HOST_NAME_MAX.

-- 
Best regards,
xhe

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Re: maybe a smaller HOST_NAME_MAX?

[Rich Felker]

On Thu, Feb 14, 2019 at 04:59:05PM +0800, He X wrote:
> in limits.h, glibc defines it as 64, musl has a valueof 255.
> 
> according a man page:
> http://man7.org/linux/man-pages/man2/gethostname.2.html. HOST_NAME_MAX is
> defined as 64 since linux 1.0. include/uapi/asm-generic/param.h could
> verify that.
> 
> as musl targeted on linux-based devices, i think it makes sense to use a
> smaller HOST_NAME_MAX.

HOST_NAME_MAX>=255 is a POSIX requirement, and also a common-sense one
since it's the length of DNS hostnames. Linux defining it as 64 is a
historical bug. I'm not sure if the modern kernel interfaces let you
set a larger one or not, but from an API standpoint, applications need
to be prepared for the possibility of receiving a name up to the
standard length, not the buggy Linux limitation.

Rich