linux-kernel - Detection of case senstive filenames

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Message-ID: <F61457A753D573478DB768F576EEDBDB2AD019EE@SJEXCHMB09.corp.ad.broadcom.com>
Date:	Fri, 29 May 2015 18:55:00 +0000
From:	John Ulvr <julvr@...adcom.com>
To:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Detection of case senstive filenames

There are several files in Linux whose names only differ by capitalization.   This has caused us some support issues due to third party filesystems/revision control systems, which overwrite the wrong file, causing non-obvious compilation errors.   I recently added a more obvious compile time failure to some of these files to reduce the number of support calls we get on the subject.   I thought I'd bring it up in case someone thinks it might be a good idea to move this to the mainstream kernel.   The code is:

  /* if your compiler generates an error here, it is likely due to a filename-capitalization error, caused by a case-insensitive filesystem or revision control system */
  #define __CHECK_FILENAME(filename) \
      static int __checkfname __attribute__((unused)) =  (1/((__builtin_strcmp((__FILE__ + __builtin_strlen(__FILE__) - __builtin_strlen(filename)), filename))?0:1))
  __CHECK_FILENAME("xt_dscp.c");

(This would appear at the bottom of xt_DSCP.c, xt_dscp.c, etc.  in global scope).     While not overly pretty, it does point out what the actual error is, and doesn't have any side-effects.    If there's interest, let me know and I can try to push it upstream.

John

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