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

/**************************************************************************
gPXE -  Network Bootstrap Program

Literature dealing with the network protocols:
        ARP - RFC826
        RARP - RFC903
        UDP - RFC768
        BOOTP - RFC951, RFC2132 (vendor extensions)
        DHCP - RFC2131, RFC2132 (options)
        TFTP - RFC1350, RFC2347 (options), RFC2348 (blocksize), RFC2349 (tsize)
        RPC - RFC1831, RFC1832 (XDR), RFC1833 (rpcbind/portmapper)

**************************************************************************/

FILE_LICENCE ( GPL2_OR_LATER );

#include <stdio.h>
#include <gpxe/init.h>
#include <gpxe/features.h>
#include <gpxe/shell.h>
#include <gpxe/shell_banner.h>
#include <gpxe/image.h>
#include <usr/autoboot.h>
#include <config/general.h>

#define NORMAL  "\033[0m"
#define BOLD    "\033[1m"
#define CYAN    "\033[36m"

/**
 * Main entry point
 *
 * @ret rc              Return status code
 */
__asmcall int main ( void ) {
        struct feature *feature;
        struct image *image;

        /* Some devices take an unreasonably long time to initialise */
        printf ( PRODUCT_SHORT_NAME " initialising devices...\n" );

        initialise();
        startup();

        /*
         * Print welcome banner
         *
         *
         * If you wish to brand this build of gPXE, please do so by
         * defining the string PRODUCT_NAME in config/general.h.
         *
         * While nothing in the GPL prevents you from removing all
         * references to gPXE or http://etherboot.org, we prefer you
         * not to do so.
         *
         */
        printf ( NORMAL "\n\n" PRODUCT_NAME "\n" BOLD "gPXE " VERSION
                 NORMAL " -- Open Source Boot Firmware -- "
                 CYAN "http://etherboot.org" NORMAL "\n"
                 "Features:" );
        for_each_table_entry ( feature, FEATURES )
                printf ( " %s", feature->name );
        printf ( "\n" );

        /* Prompt for shell */
        if ( shell_banner() ) {
                /* User wants shell; just give them a shell */
                shell();
        } else {
                /* User doesn't want shell; load and execute the first
                 * image, or autoboot() if we have no images.  If
                 * booting fails for any reason, offer a second chance
                 * to enter the shell for diagnostics.
                 */
                if ( have_images() ) {
                        for_each_image ( image ) {
                                image_exec ( image );
                                break;
                        }
                } else {
                        autoboot();
                }

                if ( shell_banner() )
                        shell();
        }

        shutdown ( SHUTDOWN_EXIT | shutdown_exit_flags );

        return 0;
}