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From: Robert Nordier <rnordier@iafrica.com>
Message-Id: <199605092114.XAA02591@eac.iafrica.com>
Subject: [Q] Raw interface to block devices
To: hackers@freebsd.org
Date: Thu, 9 May 1996 23:14:48 +0200 (SAT)
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I have a function

   int process(const char *fs);

which expects 'fs' to refer to a device which may hold a filesystem.

The function actually works with the raw device, but allows the
user some flexibility.  Eg:

   process("/dev/rfd0"); or
   process("/dev/fd0");

An obvious, though clumsy, approach is:

   stat()
   if {S_IFCHR, S_IFBLK}
      derive the other name by deleting/inserting an 'r' somewhere
      stat()
      check for (reversed) {S_IFCHR, S_IFBLK}

This tries to ensure we are not dealing with (say) '/dev/tty'; and
to come up with the device name needed.

However, something like

   ln -s /dev/fd0 floppy

causes problems.

There must be a better way to do this.  The stuff I've looked at
either trustingly waits forever on '/dev/tty', or refuses to even
consider 'floppy'.

Surely a library function is needed (or already exists).

--
Robert Nordier