Date: Mon, 20 Nov 2017 10:30:42 -0800 From: Conrad Meyer <cem@freebsd.org> To: Karl Denninger <karl@denninger.net> Cc: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org> Subject: Re: MSDOS Filesystem question related to "read-only" files Message-ID: <CAG6CVpUZumZaU9xVcri1Ry8=C6j6JrjX5F6qd3oKatYZXFu6Kg@mail.gmail.com> In-Reply-To: <f4ccb904-63fd-4641-89c8-09357fbb5a1c@denninger.net> References: <f4ccb904-63fd-4641-89c8-09357fbb5a1c@denninger.net>
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Hi Karl, In fact, msdosfs in FreeBSD should set the FAT READONLY attribute under two conditions: 1. The owner chmod's the file non-writeable (chmod u-w) (what you've described, I think). Or, 2. The super user or otherwise privileged user sets the "readonly" flag on the file via chflags(1). How have you determined that chmod u-w does nothing? What version of FreeBSD are you using? Best, Conrad On Mon, Nov 20, 2017 at 7:36 AM, Karl Denninger <karl@denninger.net> wrote: > I'm running into an interesting issue here and wondering if there's a > way to do this under FreeBSD. > > MSDOS filesystems have a "primitive" permission capability; > specifically, they can have a "Read-only" attribute on a file. It looks > like OpenBSD supports this from reading their man pages. > > FreeBSD doesn't appear to. When you mount a msdos filesystem (e.g. a > USB stick) whoever owns the parent directory where you mount it gives > you the permissions and "ownership" of files on said filesystem. All > good so far. But attempting to chmod a file to remove write permission > "succeeds" (returns success) but does nothing. > > Is this capability simply not present on FreeBSD? I'm interested in > using it as a means of "flagging" files on a USB stick in an application > that I do not want to remove if the stick fills (basically, to "protect" > them from being aged off) and it appears there's no way to do it, other > than to use something unique in the filename that I would then have to > pay attention to. > > -- > Karl Denninger > karl@denninger.net <mailto:karl@denninger.net> > /The Market Ticker/ > /[S/MIME encrypted email preferred]/
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