Re: [Netatalk-devel] AppleDouble is broken by long fileneme (>255 UTF8-MAC chars)

[Frank L. <fra...@go...>]

2011/1/27 HAT <ha...@fa...>:
> Why 765?
>
> -------------------------------------------------------------
> U+0 - U+7F (ASCII)
>
> UTF8-MAC:  1 [character] = 1 [byte]
> UTF16-MAC: 1 [character] = 1 [codepoint]
>
> AFP / HFS+
>    = UTF8-MAC / UTF16-MAC
>    = 1 [byte] / 1 [codepoint]
>    = 1 [byte/codepoint]
>
> -------------------------------------------------------------
> U+80 - U+7FF (non-ASCII Alphabet, etc)
>
> UTF8-MAC:  1 [character] = 2 [byte]
> UTF16-MAC: 1 [character] = 1 [codepoint]
>
> AFP / HFS+
>    = UTF8-MAC / UTF16-MAC
>    = 2 [byte] / 1 [codepoint]
>    = 2 [byte/codepoint]
>
> -------------------------------------------------------------
> U+800 - U+FFFF (CJK, etc)
>
> UTF8-MAC:  1 [character] = 3 [byte]
> UTF16-MAC: 1 [character] = 1 [codepoint]
>
> AFP / HFS+
>    = UTF8-MAC / UTF16-MAC
>    = 3 [byte] / 1 [codepoint]
>    = 3 [byte/codepoint]
>
> -------------------------------------------------------------
> U+10000 - U+10FFFF (Surrogate Pair)
>
> UTF8-MAC:  1 [character] = 4 [byte]
> UTF16-MAC: 1 [character] = 2 [codepoint]
>
> AFP / HFS+
>    = UTF8-MAC / UTF16-MAC
>    = 4 [byte] / 2 [codepoint]
>    = 2 [byte/codepoint]
>
> -------------------------------------------------------------
>
> Therefore,
> Max 3 [byte/codepoint]
>
> -------------------------------------------------------------
> HFS+'s max filename is 255 [codepoint].
>
> 255 [codepoint] * 3 [byte/codepoint] = 765 [byte]
>
> Max is 765 [byte] on AFP.

Only because the most used (ok, ok, in fact the only real one, but
nevertheless...) AFP clients local filesystem (HFS+) is limited to 255
codepoints, doesn't mean afpd should _impose_ this limit. Instead, as
already said, afpd should just accept any length up to AFP maxlen (65k
afair), apply MAXPATHLEN (which is needed due to our static buffers
eg), use the resulting name in OS calls and pass error back to the
client once afpd hits PATH_MAX server side.

-f