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/*
Copyright (C) 1993, 1994, 1996 Free Software Foundation
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "iohelp.h"
#include <errno.h>
/* Check to see if the user identified by USER has conch C; if not,
return an error, else, return 0. */
error_t
iohelp_verify_user_conch (struct conch *c, void *user)
{
struct shared_io *user_sh;
if (user != c->holder)
return EPERM;
user_sh = c->holder_shared_page;
spin_lock (&user_sh->lock);
if (user_sh->conch_status != USER_HAS_CONCH
&& user_sh->conch_status != USER_RELEASE_CONCH)
{
spin_unlock (&user_sh->lock);
return EPERM;
}
spin_unlock (&user_sh->lock);
return 0;
}
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