linux-kernel - Re: [PATCH] [trivial] fs/vfat: add *.cmd to filenames listed as executable by mount option "showexec"

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Message-ID: <20120203095550.GA12435@mobil.systemanalysen.net>
Date:	Fri, 3 Feb 2012 10:55:50 +0100
From:	Roland Eggner <edvx1@...temanalysen.net>
To:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [trivial] fs/vfat: add *.cmd to filenames listed as
 executable by mount option "showexec"

On 2012-02-03 Fr 16:41:16 +0900, OGAWA Hirofumi wrote:
> Roland Eggner <edvx1@...temanalysen.net> writes:
> 
> > The mount option "showexec" provides a somewhat more native view of vfat
> > filesystems:  only filenames *.exe *.com *.bat are listed as executable, rather
> > than all files.  This patch adds filenames *.cmd to those listed as executable.
> > *.cmd are usually scripts associated with the shell "cmd.exe", which has been
> > the default shell in several OS versions of its vendor.
> >
> > Signed-off-by: Roland Eggner <edvx1@...temanalysen.net>
> > ---
> 
> Hm, this may be good for someone, but this may not be for someone. So,
> this probably should be option if someone really care it.
> 
> I'm not thinking about how though...
> 
Think of VM images of recent versions of the FAT originating OS:  currently
"showexec" will miss roughly half of the files, for which it is intended for.
IMHO this patch provides a very cheap completion of a feature of the vfat kernel
module.  Cheap in terms of only 9 characters additional source code.

If you really see an advantage in the current, incomplete state of the
"showexec" feature, compared to the proposed, completed state:  please elaborate
your objection.

> > --- a/Documentation/filesystems/vfat.txt	2011-10-24 09:10:05.000000000 +0200
> > +++ b/Documentation/filesystems/vfat.txt	2012-02-03 07:26:30.457441230 +0100
> > @@ -114,7 +114,7 @@
> >  
> >  showexec      -- If set, the execute permission bits of the file will be
> >  		 allowed only if the extension part of the name is .EXE,
> > -		 .COM, or .BAT. Not set by default.
> > +		 .COM, .BAT or .CMD.  Not set by default.
> >  
> >  debug         -- Can be set, but unused by the current implementation.
> >  
> > --- a/fs/fat/inode.c	2012-02-03 06:23:35.721409360 +0100
> > +++ b/fs/fat/inode.c	2012-01-23 01:35:29.000000000 +0100
> > @@ -326,7 +326,7 @@ struct inode *fat_iget(struct super_bloc
> >  
> >  static int is_exec(unsigned char *extension)
> >  {
> > -	unsigned char *exe_extensions = "EXECOMBAT", *walk;
> > +	unsigned char *exe_extensions = "EXECOMBATCMD", *walk;
> >  
> >  	for (walk = exe_extensions; *walk; walk += 3)
> >  		if (!strncmp(extension, walk, 3))

-- 
Roland Eggner <edvx1@...temanalysen.net>

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