Alessandro,
first of all thanks a lot for your comprehensive response. I have to admit that I'm not such an expert in this area as you may believe. So some of my comments and questions may sound pretty dumb to you. Ok, here we go:
Am 03.01.2013 17:41, schrieb Alessandro Vesely:
On Mon 31/Dec/2012 17:38:06 +0100 Michael Heydekamp wrote:
From a practical side of view, the still open question for us is: How to (re)build a fixed magic.mgc which does at least support "Return-Path:", "Return-path:" and "return-path:"?
libmagic provides for case insensitive comparisons. For file-5.12, the latest version, there are "c" and "C" switches that make the comparison fully case insensitive. For file-5.04, the version on debian squeeze, only "c" seems to be provided, hence it would be necessary to rewrite the magic test string in all-lowercase.
Here's my first dumb question: What exactly is the connection between the PHP function 'finfo' and the Linux command 'file'? Does 'finfo' internally use the output of the 'file' command?
I thought 'finfo' would be a separate (PHP) function, fully independent of 'file'?!
BTW, that spurious text/x-mail mime type has been removed from the source in file-5.10.
I know, I have the sources of file-5.11 on our system as well (see my post to this list of 27.12.2012, 23:53).
But when I run a compiled file-5.11 against an .eml with "Return-path:" in the first line, it produces the same result as file-5.04: "text/x-mail" Stunning...
The resulting behavior is equivalent to using MAGIC_NO_CHECK_TOKENS. PHP doesn't define such constant, but it is defined as 0x100000 in src/magic.h. What happens if you run, say,
php -r '$f=new finfo(FILEINFO_MIME|0x100000); print $f->file("YOUR.eml")."\n";'
Although I don't understand what I'm (and this command is) exactly doing, the result is:
"text/plain"; charset=us-ascii"
So not "text/x-mail" anymore, but also still not "message/rfc822".
If I replace file-5.04 with file-5.11 and run the command above, I get the same "text/plain" result.
(Although I have file-5.04 too, on debian squeeze, I'm unable to get text/x-mail: I get text/plain for "Return-path:".)
Strange. Probably because of a different magic.mgc file...?
Plus that finfo is apparently also able to load a plain text file instead of a compiled magic.mgc, but it doesn't load every magic text file that I can find on our server. I will have to dig a little deeper into that issue, unless somebody else can help with more specific information.
What PHP version does roundcube require?
According to http://www.roundcube.net/about: PHP Version 5.2.1 or greater
According to the Notes at http://php.net/manual/en/function.finfo-open.php, PHP >= 5.3.11 and >= 5.4.1 upgraded to libmagic 5.
Well, we're running 5.3.3-7+squeeze14 with Suhosin-Patch (cli), AFAICS.
However, slight changes in the format of the magic file are possible even between minor versions.
Yeah, but I have no idea how to compile a magic.mgc at all (which text file I have to use as a basis, where to get the latest one, what exactly to do with it, etc. pp.).
But anyway, thanks again!
Michael Heydekamp Co-Admin freexp.de Düsseldorf/Germany