autoboot.c

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/*
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );

#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <ipxe/netdevice.h>
#include <ipxe/vlan.h>
#include <ipxe/dhcp.h>
#include <ipxe/settings.h>
#include <ipxe/image.h>
#include <ipxe/sanboot.h>
#include <ipxe/uri.h>
#include <ipxe/open.h>
#include <ipxe/init.h>
#include <ipxe/keys.h>
#include <ipxe/version.h>
#include <ipxe/shell.h>
#include <ipxe/features.h>
#include <ipxe/image.h>
#include <ipxe/timer.h>
#include <usr/ifmgmt.h>
#include <usr/route.h>
#include <usr/imgmgmt.h>
#include <usr/prompt.h>
#include <usr/autoboot.h>
#include <config/general.h>
#include <config/branding.h>

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

/** Link-layer address of preferred autoboot device, if known */
static uint8_t autoboot_ll_addr[MAX_LL_ADDR_LEN];

/** VLAN tag of preferred autoboot device, if known */
static unsigned int autoboot_vlan;

/** Device location of preferred autoboot device, if known */
static struct device_description autoboot_desc;

/** Autoboot device tester */
static int ( * is_autoboot_device ) ( struct net_device *netdev );

/* Disambiguate the various error causes */
#define ENOENT_BOOT __einfo_error ( EINFO_ENOENT_BOOT )
#define EINFO_ENOENT_BOOT \
        __einfo_uniqify ( EINFO_ENOENT, 0x01, "Nothing to boot" )

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

/** The "scriptlet" setting */
const struct setting scriptlet_setting __setting ( SETTING_MISC, scriptlet ) = {
        .name = "scriptlet",
        .description = "Boot scriptlet",
        .tag = DHCP_EB_SCRIPTLET,
        .type = &setting_type_string,
};

/**
 * Perform PXE menu boot when PXE stack is not available
 */
__weak int pxe_menu_boot ( struct net_device *netdev __unused ) {
        return -ENOTSUP;
}

/** The "keep-san" setting */
const struct setting keep_san_setting __setting ( SETTING_SANBOOT_EXTRA,
                                                  keep-san ) = {
        .name = "keep-san",
        .description = "Preserve SAN connection",
        .tag = DHCP_EB_KEEP_SAN,
        .type = &setting_type_int8,
};

/** The "skip-san-boot" setting */
const struct setting skip_san_boot_setting __setting ( SETTING_SANBOOT_EXTRA,
                                                       skip-san-boot ) = {
        .name = "skip-san-boot",
        .description = "Do not boot from SAN device",
        .tag = DHCP_EB_SKIP_SAN_BOOT,
        .type = &setting_type_int8,
};

/**
 * Boot from filename and root-path URIs
 *
 * @v filename          Filename
 * @v root_paths        Root path(s)
 * @v root_path_count   Number of root paths
 * @v drive             SAN drive (if applicable)
 * @v san_config        SAN boot configuration parameters
 * @v flags             Boot action flags
 * @ret rc              Return status code
 *
 * The somewhat tortuous flow of control in this function exists in
 * order to ensure that the "sanboot" command remains identical in
 * function to a SAN boot via a DHCP-specified root path, and to
 * provide backwards compatibility for the "keep-san" and
 * "skip-san-boot" options.
 */
int uriboot ( struct uri *filename, struct uri **root_paths,
              unsigned int root_path_count, int drive,
              struct san_boot_config *san_config, unsigned int flags ) {
        struct image *image;
        const char *san_filename;
        int rc;

        /* Hook SAN device, if applicable */
        if ( root_path_count ) {
                drive = san_hook ( drive, root_paths, root_path_count,
                                   ( ( flags & URIBOOT_NO_SAN_DESCRIBE ) ?
                                     SAN_NO_DESCRIBE : 0 ) );
                if ( drive < 0 ) {
                        rc = drive;
                        printf ( "Could not open SAN device: %s\n",
                                 strerror ( rc ) );
                        goto err_san_hook;
                }
                printf ( "Registered SAN device %#02x\n", drive );
        }

        /* Describe SAN device, if applicable */
        if ( ! ( flags & URIBOOT_NO_SAN_DESCRIBE ) ) {
                if ( ( rc = san_describe() ) != 0 ) {
                        printf ( "Could not describe SAN devices: %s\n",
                                 strerror ( rc ) );
                        goto err_san_describe;
                }
        }

        /* Allow a root-path-only boot with skip-san enabled to succeed */
        rc = 0;

        /* Attempt filename boot if applicable */
        if ( filename ) {
                if ( ( rc = imgdownload ( filename, 0, &image ) ) != 0 )
                        goto err_download;
                imgstat ( image );
                image->flags |= IMAGE_AUTO_UNREGISTER;
                if ( ( rc = image_exec ( image ) ) != 0 ) {
                        printf ( "Could not boot image: %s\n",
                                 strerror ( rc ) );
                        /* Fall through to (possibly) attempt a SAN boot
                         * as a fallback.  If no SAN boot is attempted,
                         * our status will become the return status.
                         */
                } else {
                        /* Always print an extra newline, because we
                         * don't know where the NBP may have left the
                         * cursor.
                         */
                        printf ( "\n" );
                }
        }

        /* Attempt SAN boot if applicable */
        if ( ! ( flags & URIBOOT_NO_SAN_BOOT ) ) {
                san_filename = san_config->filename;
                if ( fetch_intz_setting ( NULL, &skip_san_boot_setting) == 0 ) {
                        printf ( "Booting%s%s from SAN device %#02x\n",
                                 ( san_filename ? " " : "" ),
                                 ( san_filename ? san_filename : "" ), drive );
                        rc = san_boot ( drive, san_config );
                        printf ( "Boot from SAN device %#02x failed: %s\n",
                                 drive, strerror ( rc ) );
                } else {
                        printf ( "Skipping boot from SAN device %#02x\n",
                                 drive );
                        /* Avoid overwriting a possible failure status
                         * from a filename boot.
                         */
                }
        }

 err_download:
 err_san_describe:
        /* Unhook SAN device, if applicable */
        if ( ! ( flags & URIBOOT_NO_SAN_UNHOOK ) ) {
                if ( fetch_intz_setting ( NULL, &keep_san_setting ) == 0 ) {
                        san_unhook ( drive );
                        printf ( "Unregistered SAN device %#02x\n", drive );
                } else {
                        printf ( "Preserving SAN device %#02x\n", drive );
                }
        }
 err_san_hook:
        return rc;
}

/**
 * Close all but one network device
 *
 * 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_other_netdevs ( struct net_device *netdev ) {
        struct net_device *other;

        for_each_netdev ( other ) {
                if ( other != netdev )
                        ifclose ( other );
        }
}

/**
 * Fetch next-server and filename settings into a URI
 *
 * @v settings          Settings block
 * @ret uri             URI, or NULL on failure
 */
struct uri * fetch_next_server_and_filename ( struct settings *settings ) {
        union {
                struct sockaddr sa;
                struct sockaddr_in sin;
        } next_server;
        char *raw_filename = NULL;
        struct uri *uri = NULL;
        char *filename;

        /* Initialise server address */
        memset ( &next_server, 0, sizeof ( next_server ) );

        /* If we have a filename, fetch it along with the next-server
         * setting from the same settings block.
         */
        if ( fetch_setting ( settings, &filename_setting, &settings,
                             NULL, NULL, 0 ) >= 0 ) {
                fetch_string_setting_copy ( settings, &filename_setting,
                                            &raw_filename );
                fetch_ipv4_setting ( settings, &next_server_setting,
                                     &next_server.sin.sin_addr );
        }
        if ( ! raw_filename )
                goto err_fetch;

        /* Populate server address */
        if ( next_server.sin.sin_addr.s_addr ) {
                next_server.sin.sin_family = AF_INET;
                printf ( "Next server: %s\n",
                         inet_ntoa ( next_server.sin.sin_addr ) );
        }

        /* Expand filename setting */
        filename = expand_settings ( raw_filename );
        if ( ! filename )
                goto err_expand;
        if ( filename[0] )
                printf ( "Filename: %s\n", filename );

        /* Construct URI */
        uri = pxe_uri ( &next_server.sa, filename );
        if ( ! uri )
                goto err_parse;

 err_parse:
        free ( filename );
 err_expand:
        free ( raw_filename );
 err_fetch:
        return uri;
}

/**
 * Fetch root-path setting into a URI
 *
 * @v settings          Settings block
 * @ret uri             URI, or NULL on failure
 */
static struct uri * fetch_root_path ( struct settings *settings ) {
        struct uri *uri = NULL;
        char *raw_root_path;
        char *root_path;

        /* Fetch root-path setting */
        fetch_string_setting_copy ( settings, &root_path_setting,
                                    &raw_root_path );
        if ( ! raw_root_path )
                goto err_fetch;

        /* Expand filename setting */
        root_path = expand_settings ( raw_root_path );
        if ( ! root_path )
                goto err_expand;
        if ( root_path[0] )
                printf ( "Root path: %s\n", root_path );

        /* Parse root path */
        uri = parse_uri ( root_path );
        if ( ! uri )
                goto err_parse;

 err_parse:
        free ( root_path );
 err_expand:
        free ( raw_root_path );
 err_fetch:
        return uri;
}

/**
 * Fetch san-filename setting
 *
 * @v settings          Settings block
 * @ret san_filename    SAN filename, or NULL on failure
 */
static char * fetch_san_filename ( struct settings *settings ) {
        char *raw_san_filename;
        char *san_filename = NULL;

        /* Fetch san-filename setting */
        fetch_string_setting_copy ( settings, &san_filename_setting,
                                    &raw_san_filename );
        if ( ! raw_san_filename )
                goto err_fetch;

        /* Expand san-filename setting */
        san_filename = expand_settings ( raw_san_filename );
        if ( ! san_filename )
                goto err_expand;
        if ( san_filename[0] )
                printf ( "SAN filename: %s\n", san_filename );

 err_expand:
        free ( raw_san_filename );
 err_fetch:
        return san_filename;
}

/**
 * Check whether or not we have a usable PXE menu
 *
 * @ret have_menu       A usable PXE menu is present
 */
static int have_pxe_menu ( void ) {
        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[ 10 /* "PXEClient" + NUL */ ];
        unsigned int pxe_discovery_control;

        fetch_string_setting ( NULL, &vendor_class_id_setting,
                               buf, sizeof ( buf ) );
        pxe_discovery_control =
                fetch_uintz_setting ( NULL, &pxe_discovery_control_setting );

        return ( ( strcmp ( buf, "PXEClient" ) == 0 ) &&
                 setting_exists ( NULL, &pxe_boot_menu_setting ) &&
                 ( ! ( ( pxe_discovery_control & PXEBS_SKIP ) &&
                       setting_exists ( NULL, &filename_setting ) ) ) );
}

/**
 * Boot from a network device
 *
 * @v netdev            Network device
 * @ret rc              Return status code
 */
int netboot ( struct net_device *netdev ) {
        struct san_boot_config san_config;
        struct uri *filename;
        struct uri *root_path;
        char *san_filename;
        int rc;

        /* Close all other network devices */
        close_other_netdevs ( netdev );

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

        /* Configure device */
        if ( ( rc = ifconf ( netdev, NULL, 0 ) ) != 0 )
                goto err_dhcp;
        route();

        /* Try PXE menu boot, if applicable */
        if ( have_pxe_menu() ) {
                printf ( "Booting from PXE menu\n" );
                rc = pxe_menu_boot ( netdev );
                goto err_pxe_menu_boot;
        }

        /* Fetch next server and filename (if any) */
        filename = fetch_next_server_and_filename ( NULL );

        /* Fetch root path (if any) */
        root_path = fetch_root_path ( NULL );

        /* Fetch SAN filename (if any) */
        san_filename = fetch_san_filename ( NULL );

        /* Construct SAN boot configuration parameters */
        memset ( &san_config, 0, sizeof ( san_config ) );
        san_config.filename = san_filename;

        /* If we have both a filename and a root path, ignore an
         * unsupported or missing URI scheme in the root path, since
         * it may represent an NFS root.
         */
        if ( filename && root_path &&
             ( ( ! uri_is_absolute ( root_path ) ) ||
               ( xfer_uri_opener ( root_path->scheme ) == NULL ) ) ) {
                printf ( "Ignoring unsupported root path\n" );
                uri_put ( root_path );
                root_path = NULL;
        }

        /* Check that we have something to boot */
        if ( ! ( filename || root_path ) ) {
                rc = -ENOENT_BOOT;
                printf ( "Nothing to boot: %s\n", strerror ( rc ) );
                goto err_no_boot;
        }

        /* Boot using next server, filename and root path */
        if ( ( rc = uriboot ( filename, &root_path, ( root_path ? 1 : 0 ),
                              san_default_drive(), &san_config,
                              ( root_path ? 0 : URIBOOT_NO_SAN ) ) ) != 0 )
                goto err_uriboot;

 err_uriboot:
 err_no_boot:
        free ( san_filename );
        uri_put ( root_path );
        uri_put ( filename );
 err_pxe_menu_boot:
 err_dhcp:
 err_ifopen:
        return rc;
}

/**
 * Test if network device matches the autoboot device bus type and location
 *
 * @v netdev            Network device
 * @ret is_autoboot     Network device matches the autoboot device
 */
static int is_autoboot_busloc ( struct net_device *netdev ) {
        struct device *dev;

        for ( dev = netdev->dev ; dev ; dev = dev->parent ) {
                if ( ( dev->desc.bus_type == autoboot_desc.bus_type ) &&
                     ( dev->desc.location == autoboot_desc.location ) )
                        return 1;
        }
        return 0;
}

/**
 * Identify autoboot device by bus type and location
 *
 * @v bus_type          Bus type
 * @v location          Location
 */
void set_autoboot_busloc ( unsigned int bus_type, unsigned int location ) {

        /* Record autoboot device description */
        autoboot_desc.bus_type = bus_type;
        autoboot_desc.location = location;

        /* Mark autoboot device as present */
        is_autoboot_device = is_autoboot_busloc;
}

/**
 * Test if network device matches the autoboot device link-layer address
 *
 * @v netdev            Network device
 * @ret is_autoboot     Network device matches the autoboot device
 */
static int is_autoboot_ll_addr ( struct net_device *netdev ) {

        return ( ( memcmp ( netdev->ll_addr, autoboot_ll_addr,
                            netdev->ll_protocol->ll_addr_len ) == 0 ) &&
                 ( vlan_tag ( netdev ) == autoboot_vlan ) );
}

/**
 * Identify autoboot device by link-layer address
 *
 * @v ll_addr           Link-layer address
 * @v len               Length of link-layer address
 * @v vlan              VLAN tag
 */
void set_autoboot_ll_addr ( const void *ll_addr, size_t len,
                            unsigned int vlan ) {

        /* Record autoboot link-layer address (truncated if necessary) */
        if ( len > sizeof ( autoboot_ll_addr ) )
                len = sizeof ( autoboot_ll_addr );
        memcpy ( autoboot_ll_addr, ll_addr, len );

        /* Record autoboot VLAN tag */
        autoboot_vlan = vlan;

        /* Mark autoboot device as present */
        is_autoboot_device = is_autoboot_ll_addr;
}

/**
 * Boot the system
 */
static int autoboot ( void ) {
        struct net_device *netdev;
        int rc = -ENODEV;

        /* Try booting from each network device.  If we have a
         * specified autoboot device location, then use only devices
         * matching that location.
         */
        for_each_netdev ( netdev ) {

                /* Skip any non-matching devices, if applicable */
                if ( is_autoboot_device && ( ! is_autoboot_device ( netdev ) ) )
                        continue;

                /* Attempt booting from this device */
                rc = netboot ( netdev );
        }

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

/**
 * Prompt for shell entry
 *
 * @ret enter_shell     User wants to enter shell
 */
static int shell_banner ( void ) {

        /* Skip prompt if timeout is zero */
        if ( BANNER_TIMEOUT <= 0 )
                return 0;

        /* Prompt user */
        printf ( "\n" );
        return ( prompt ( "Press Ctrl-B for the " PRODUCT_SHORT_NAME
                          " command line...",
                          ( ( BANNER_TIMEOUT * TICKS_PER_SEC ) / 10 ),
                          CTRL_B ) == 0 );
}

/**
 * Main iPXE flow of execution
 *
 * @v netdev            Network device, or NULL
 * @ret rc              Return status code
 */
int ipxe ( struct net_device *netdev ) {
        struct feature *feature;
        struct image *image;
        char *scriptlet;
        int rc;

        /*
         * Print welcome banner
         *
         *
         * If you wish to brand this build of iPXE, please do so by
         * defining the string PRODUCT_NAME in config/branding.h.
         *
         * While nothing in the GPL prevents you from removing all
         * references to iPXE or https://ipxe.org, we prefer you not
         * to do so.
         *
         */
        printf ( NORMAL "\n\n" PRODUCT_NAME "\n" BOLD PRODUCT_SHORT_NAME " %s"
                 NORMAL " -- " PRODUCT_TAG_LINE " -- "
                 CYAN PRODUCT_URI NORMAL "\nFeatures:", product_version );
        for_each_table_entry ( feature, FEATURES )
                printf ( " %s", feature->name );
        printf ( "\n" );

        /* Boot system */
        if ( ( image = first_image() ) != NULL ) {
                /* We have an embedded image; execute it */
                return image_exec ( image );
        } else if ( shell_banner() ) {
                /* User wants shell; just give them a shell */
                return shell();
        } else {
                fetch_string_setting_copy ( NULL, &scriptlet_setting,
                                            &scriptlet );
                if ( scriptlet ) {
                        /* User has defined a scriptlet; execute it */
                        rc = system ( scriptlet );
                        free ( scriptlet );
                        return rc;
                } else {
                        /* Try booting.  If booting fails, offer the
                         * user another chance to enter the shell.
                         */
                        if ( netdev ) {
                                rc = netboot ( netdev );
                        } else {
                                rc = autoboot();
                        }
                        if ( shell_banner() )
                                rc = shell();
                        return rc;
                }
        }
}