source: bootcd/isolinux/syslinux-6.03/gpxe/src/core/init.c

/*
 * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * 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 of the
 * License, or 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.
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <gpxe/device.h>
#include <gpxe/init.h>

/** @file
 *
 * Initialisation, startup and shutdown routines
 *
 */

/** "startup() has been called" flag */
static int started = 0;

/**
 * Initialise gPXE
 *
 * This function performs the one-time-only and irreversible
 * initialisation steps, such as initialising the heap.  It must be
 * called before (almost) any other function.
 *
 * There is, by definition, no counterpart to this function on the
 * shutdown path.
 */
void initialise ( void ) {
        struct init_fn *init_fn;

        /* Call registered initialisation functions */
        for_each_table_entry ( init_fn, INIT_FNS )
                init_fn->initialise ();
}

/**
 * Start up gPXE
 *
 * This function performs the repeatable initialisation steps, such as
 * probing devices.  You may call startup() and shutdown() multiple
 * times (as is done via the PXE API when PXENV_START_UNDI is used).
 */
void startup ( void ) {
        struct startup_fn *startup_fn;

        if ( started )
                return;

        /* Call registered startup functions */
        for_each_table_entry ( startup_fn, STARTUP_FNS ) {
                if ( startup_fn->startup )
                        startup_fn->startup();
        }

        started = 1;
}

/**
 * Shut down gPXE
 *
 * @v flags             Shutdown behaviour flags
 *
 * This function reverses the actions of startup(), and leaves gPXE in
 * a state ready to be removed from memory.  You may call startup()
 * again after calling shutdown().
 *
 * Call this function only once, before either exiting main() or
 * starting up a non-returnable image.
 */
void shutdown ( int flags ) {
        struct startup_fn *startup_fn;

        if ( ! started )
                return;

        /* Call registered shutdown functions (in reverse order) */
        for_each_table_entry_reverse ( startup_fn, STARTUP_FNS ) {
                if ( startup_fn->shutdown )
                        startup_fn->shutdown ( flags );
        }

        started = 0;
}