source: bootcd/isolinux/syslinux-6.03/gpxe/src/usr/autoboot.c

/*
 * Copyright (C) 2006 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 <string.h>
#include <stdio.h>
#include <errno.h>
#include <gpxe/netdevice.h>
#include <gpxe/dhcp.h>
#include <gpxe/settings.h>
#include <gpxe/image.h>
#include <gpxe/sanboot.h>
#include <gpxe/uri.h>
#include <usr/ifmgmt.h>
#include <usr/route.h>
#include <usr/dhcpmgmt.h>
#include <usr/imgmgmt.h>
#include <usr/autoboot.h>

/** @file
 *
 * Automatic booting
 *
 */

/** Shutdown flags for exit */
int shutdown_exit_flags = 0;

/**
 * Identify the boot network device
 *
 * @ret netdev          Boot network device
 */
static struct net_device * find_boot_netdev ( void ) {
        return NULL;
}

/**
 * Boot using next-server and filename
 *
 * @v filename          Boot filename
 * @ret rc              Return status code
 */
int boot_next_server_and_filename ( struct in_addr next_server,
                                    const char *filename ) {
        struct uri *uri;
        struct image *image;
        char buf[ 23 /* tftp://xxx.xxx.xxx.xxx/ */ +
                  ( 3 * strlen(filename) ) /* completely URI-encoded */
                  + 1 /* NUL */ ];
        int filename_is_absolute;
        int rc;

        /* Construct URI */
        uri = parse_uri ( filename );
        if ( ! uri )
                return -ENOMEM;
        filename_is_absolute = uri_is_absolute ( uri );
        uri_put ( uri );
        if ( ! filename_is_absolute ) {
                /* Construct a tftp:// URI for the filename.  We can't
                 * just rely on the current working URI, because the
                 * relative URI resolution will remove the distinction
                 * between filenames with and without initial slashes,
                 * which is significant for TFTP.
                 */
                snprintf ( buf, sizeof ( buf ), "tftp://%s/",
                           inet_ntoa ( next_server ) );
                uri_encode ( filename, buf + strlen ( buf ),
                             sizeof ( buf ) - strlen ( buf ), URI_PATH );
                filename = buf;
        }

        image = alloc_image();
        if ( ! image )
                return -ENOMEM;
        if ( ( rc = imgfetch ( image, filename,
                               register_and_autoload_image ) ) != 0 ) {
                goto done;
        }
        if ( ( rc = imgexec ( image ) ) != 0 )
                goto done;

 done:
        image_put ( image );
        return rc;
}

/**
 * Boot using root path
 *
 * @v root_path         Root path
 * @ret rc              Return status code
 */
int boot_root_path ( const char *root_path ) {
        struct sanboot_protocol *sanboot;

        /* Quick hack */
        for_each_table_entry ( sanboot, SANBOOT_PROTOCOLS ) {
                if ( strncmp ( root_path, sanboot->prefix,
                               strlen ( sanboot->prefix ) ) == 0 ) {
                        return sanboot->boot ( root_path );
                }
        }

        return -ENOTSUP;
}

/**
 * Boot from a network device
 *
 * @v netdev            Network device
 * @ret rc              Return status code
 */
static int netboot ( struct net_device *netdev ) {
        struct setting vendor_class_id_setting
                = { .tag = DHCP_VENDOR_CLASS_ID };
        struct setting pxe_discovery_control_setting
                = { .tag = DHCP_PXE_DISCOVERY_CONTROL };
        struct setting pxe_boot_menu_setting
                = { .tag = DHCP_PXE_BOOT_MENU };
        char buf[256];
        struct in_addr next_server;
        unsigned int pxe_discovery_control;
        int rc;

        /* Open device and display device status */
        if ( ( rc = ifopen ( netdev ) ) != 0 )
                return rc;
        ifstat ( netdev );

        /* Configure device via DHCP */
        if ( ( rc = dhcp ( netdev ) ) != 0 )
                return rc;
        route();

        /* Try PXE menu boot, if applicable */
        fetch_string_setting ( NULL, &vendor_class_id_setting,
                               buf, sizeof ( buf ) );
        pxe_discovery_control =
                fetch_uintz_setting ( NULL, &pxe_discovery_control_setting );
        if ( ( strcmp ( buf, "PXEClient" ) == 0 ) && pxe_menu_boot != NULL &&
             setting_exists ( NULL, &pxe_boot_menu_setting ) &&
             ( ! ( ( pxe_discovery_control & PXEBS_SKIP ) &&
                   setting_exists ( NULL, &filename_setting ) ) ) ) {
                printf ( "Booting from PXE menu\n" );
                return pxe_menu_boot ( netdev );
        }

        /* Try to download and boot whatever we are given as a filename */
        fetch_ipv4_setting ( NULL, &next_server_setting, &next_server );
        fetch_string_setting ( NULL, &filename_setting, buf, sizeof ( buf ) );
        if ( buf[0] ) {
                printf ( "Booting from filename \"%s\"\n", buf );
                if ( ( rc = boot_next_server_and_filename ( next_server,
                                                            buf ) ) != 0 ) {
                        printf ( "Could not boot from filename \"%s\": %s\n",
                                 buf, strerror ( rc ) );
                        return rc;
                }
                return 0;
        }
        
        /* No filename; try the root path */
        fetch_string_setting ( NULL, &root_path_setting, buf, sizeof ( buf ) );
        if ( buf[0] ) {
                printf ( "Booting from root path \"%s\"\n", buf );
                if ( ( rc = boot_root_path ( buf ) ) != 0 ) {
                        printf ( "Could not boot from root path \"%s\": %s\n",
                                 buf, strerror ( rc ) );
                        return rc;
                }
                return 0;
        }

        printf ( "No filename or root path specified\n" );
        return -ENOENT;
}

/**
 * Close all open net devices
 *
 * Called before a fresh boot attempt in order to free up memory.  We
 * don't just close the device immediately after the boot fails,
 * because there may still be TCP connections in the process of
 * closing.
 */
static void close_all_netdevs ( void ) {
        struct net_device *netdev;

        for_each_netdev ( netdev ) {
                ifclose ( netdev );
        }
}

/**
 * Boot the system
 */
void autoboot ( void ) {
        struct net_device *boot_netdev;
        struct net_device *netdev;

        /* If we have an identifable boot device, try that first */
        close_all_netdevs();
        if ( ( boot_netdev = find_boot_netdev() ) )
                netboot ( boot_netdev );

        /* If that fails, try booting from any of the other devices */
        for_each_netdev ( netdev ) {
                if ( netdev == boot_netdev )
                        continue;
                close_all_netdevs();
                netboot ( netdev );
        }

        printf ( "No more network devices\n" );
}