guestinfo.c

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/*
 * Copyright (C) 2012 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.
 */

FILE_LICENCE ( GPL2_OR_LATER );

/** @file
 *
 * VMware GuestInfo settings
 *
 */

#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <ipxe/init.h>
#include <ipxe/settings.h>
#include <ipxe/netdevice.h>
#include <ipxe/guestrpc.h>

/** GuestInfo GuestRPC channel */
static int guestinfo_channel;

/**
 * Fetch value of typed GuestInfo setting
 *
 * @v settings          Settings block
 * @v setting           Setting to fetch
 * @v type              Setting type to attempt (or NULL for default)
 * @v data              Buffer to fill with setting data
 * @v len               Length of buffer
 * @ret found           Setting found in GuestInfo
 * @ret len             Length of setting data, or negative error
 */
static int guestinfo_fetch_type ( struct settings *settings,
                                  struct setting *setting,
                                  const struct setting_type *type,
                                  void *data, size_t len, int *found ) {
        const char *parent_name = settings->parent->name;
        char command[ 24 /* "info-get guestinfo.ipxe." */ +
                      strlen ( parent_name ) + 1 /* "." */ +
                      strlen ( setting->name ) + 1 /* "." */ +
                      ( type ? strlen ( type->name ) : 0 ) + 1 /* NUL */ ];
        struct setting *predefined;
        char *info;
        int info_len;
        int check_len;
        int ret;

        /* Construct info-get command */
        snprintf ( command, sizeof ( command ),
                   "info-get guestinfo.ipxe.%s%s%s%s%s",
                   parent_name, ( parent_name[0] ? "." : "" ), setting->name,
                   ( type ? "." : "" ), ( type ? type->name : "" ) );

        /* Check for existence and obtain length of GuestInfo value */
        info_len = guestrpc_command ( guestinfo_channel, command, NULL, 0 );
        if ( info_len < 0 ) {
                ret = info_len;
                goto err_get_info_len;
        }

        /* Mark as found */
        *found = 1;

        /* Determine default type if necessary */
        if ( ! type ) {
                predefined = find_setting ( setting->name );
                type = ( predefined ? predefined->type : &setting_type_string );
        }
        assert ( type != NULL );

        /* Allocate temporary block to hold GuestInfo value */
        info = zalloc ( info_len + 1 /* NUL */ );
        if ( ! info ) {
                DBGC ( settings, "GuestInfo %p could not allocate %d bytes\n",
                       settings, info_len );
                ret = -ENOMEM;
                goto err_alloc;
        }
        info[info_len] = '\0';

        /* Fetch GuestInfo value */
        check_len = guestrpc_command ( guestinfo_channel, command,
                                       info, info_len );
        if ( check_len < 0 ) {
                ret = check_len;
                goto err_get_info;
        }
        if ( check_len != info_len ) {
                DBGC ( settings, "GuestInfo %p length mismatch (expected %d, "
                       "got %d)\n", settings, info_len, check_len );
                ret = -EIO;
                goto err_get_info;
        }
        DBGC2 ( settings, "GuestInfo %p found %s = \"%s\"\n",
                settings, &command[9] /* Skip "info-get " */, info );

        /* Parse GuestInfo value according to type */
        ret = setting_parse ( type, info, data, len );
        if ( ret < 0 ) {
                DBGC ( settings, "GuestInfo %p could not parse \"%s\" as %s: "
                       "%s\n", settings, info, type->name, strerror ( ret ) );
                goto err_parse;
        }

 err_parse:
 err_get_info:
        free ( info );
 err_alloc:
 err_get_info_len:
        return ret;
}

/**
 * Fetch value of GuestInfo setting
 *
 * @v settings          Settings block
 * @v setting           Setting to fetch
 * @v data              Buffer to fill with setting data
 * @v len               Length of buffer
 * @ret len             Length of setting data, or negative error
 */
static int guestinfo_fetch ( struct settings *settings,
                             struct setting *setting,
                             void *data, size_t len ) {
        struct setting_type *type;
        int found = 0;
        int ret;

        /* Try default type first */
        ret = guestinfo_fetch_type ( settings, setting, NULL,
                                     data, len, &found );
        if ( found )
                return ret;

        /* Otherwise, try all possible types */
        for_each_table_entry ( type, SETTING_TYPES ) {
                ret = guestinfo_fetch_type ( settings, setting, type,
                                             data, len, &found );
                if ( found )
                        return ret;
        }

        /* Not found */
        return -ENOENT;
}

/** GuestInfo settings operations */
static struct settings_operations guestinfo_settings_operations = {
        .fetch = guestinfo_fetch,
};

/** GuestInfo settings */
static struct settings guestinfo_settings = {
        .refcnt = NULL,
        .siblings = LIST_HEAD_INIT ( guestinfo_settings.siblings ),
        .children = LIST_HEAD_INIT ( guestinfo_settings.children ),
        .op = &guestinfo_settings_operations,
};

/** Initialise GuestInfo settings */
static void guestinfo_init ( void ) {
        int rc;

        /* Open GuestRPC channel */
        guestinfo_channel = guestrpc_open();
        if ( guestinfo_channel < 0 ) {
                rc = guestinfo_channel;
                DBG ( "GuestInfo could not open channel: %s\n",
                      strerror ( rc ) );
                return;
        }

        /* Register root GuestInfo settings */
        if ( ( rc = register_settings ( &guestinfo_settings, NULL,
                                        "vmware" ) ) != 0 ) {
                DBG ( "GuestInfo could not register settings: %s\n",
                      strerror ( rc ) );
                return;
        }
}

/** GuestInfo settings initialiser */
struct init_fn guestinfo_init_fn __init_fn ( INIT_NORMAL ) = {
        .initialise = guestinfo_init,
};

/**
 * Create per-netdevice GuestInfo settings
 *
 * @v netdev            Network device
 * @v priv              Private data
 * @ret rc              Return status code
 */
static int guestinfo_net_probe ( struct net_device *netdev, void *priv ) {
        struct settings *settings = priv;
        int rc;

        /* Do nothing unless we have a GuestInfo channel available */
        if ( guestinfo_channel < 0 )
                return 0;

        /* Initialise and register settings */
        settings_init ( settings, &guestinfo_settings_operations,
                        &netdev->refcnt, NULL );
        if ( ( rc = register_settings ( settings, netdev_settings ( netdev ),
                                        "vmware" ) ) != 0 ) {
                DBGC ( settings, "GuestInfo %p could not register for %s: %s\n",
                       settings, netdev->name, strerror ( rc ) );
                return rc;
        }
        DBGC ( settings, "GuestInfo %p registered for %s\n",
               settings, netdev->name );

        return 0;
}

/** GuestInfo per-netdevice driver */
struct net_driver guestinfo_net_driver __net_driver = {
        .name = "GuestInfo",
        .priv_len = sizeof ( struct settings ),
        .probe = guestinfo_net_probe,
};