runtime.c

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/*
 * Copyright (C) 2011 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
 *
 * Command line and initrd passed to iPXE at runtime
 *
 */

#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <ctype.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/init.h>
#include <ipxe/image.h>
#include <ipxe/script.h>
#include <realmode.h>

/** Command line physical address
 *
 * This can be set by the prefix.
 */
uint32_t __bss16 ( cmdline_phys );
#define cmdline_phys __use_data16 ( cmdline_phys )

/** initrd physical address
 *
 * This can be set by the prefix.
 */
uint32_t __bss16 ( initrd_phys );
#define initrd_phys __use_data16 ( initrd_phys )

/** initrd length
 *
 * This can be set by the prefix.
 */
uint32_t __bss16 ( initrd_len );
#define initrd_len __use_data16 ( initrd_len )

/** Internal copy of the command line */
static char *cmdline_copy;

/** Free command line image */
static void cmdline_image_free ( struct refcnt *refcnt ) {
        struct image *image = container_of ( refcnt, struct image, refcnt );

        DBGC ( image, "RUNTIME freeing command line\n" );
        free ( cmdline_copy );
}

/** Embedded script representing the command line */
static struct image cmdline_image = {
        .refcnt = REF_INIT ( cmdline_image_free ),
        .name = "<CMDLINE>",
        .type = &script_image_type,
};

/** Colour for debug messages */
#define colour &cmdline_image

/**
 * Strip unwanted cruft from command line
 *
 * @v cmdline           Command line
 * @v cruft             Initial substring of cruft to strip
 */
static void cmdline_strip ( char *cmdline, const char *cruft ) {
        char *strip;
        char *strip_end;

        /* Find unwanted cruft, if present */
        if ( ! ( strip = strstr ( cmdline, cruft ) ) )
                return;

        /* Strip unwanted cruft */
        strip_end = strchr ( strip, ' ' );
        if ( strip_end ) {
                *strip_end = '\0';
                DBGC ( colour, "RUNTIME stripping \"%s\"\n", strip );
                strcpy ( strip, ( strip_end + 1 ) );
        } else {
                DBGC ( colour, "RUNTIME stripping \"%s\"\n", strip );
                *strip = '\0';
        }
}

/**
 * Initialise command line
 *
 * @ret rc              Return status code
 */
static int cmdline_init ( void ) {
        userptr_t cmdline_user;
        char *cmdline;
        size_t len;
        int rc;

        /* Do nothing if no command line was specified */
        if ( ! cmdline_phys ) {
                DBGC ( colour, "RUNTIME found no command line\n" );
                return 0;
        }
        cmdline_user = phys_to_user ( cmdline_phys );
        len = ( strlen_user ( cmdline_user, 0 ) + 1 /* NUL */ );

        /* Allocate and copy command line */
        cmdline_copy = malloc ( len );
        if ( ! cmdline_copy ) {
                DBGC ( colour, "RUNTIME could not allocate %zd bytes for "
                       "command line\n", len );
                rc = -ENOMEM;
                goto err_alloc_cmdline_copy;
        }
        cmdline = cmdline_copy;
        copy_from_user ( cmdline, cmdline_user, 0, len );
        DBGC ( colour, "RUNTIME found command line \"%s\" at %08x\n",
               cmdline, cmdline_phys );

        /* Mark command line as consumed */
        cmdline_phys = 0;

        /* Strip unwanted cruft from the command line */
        cmdline_strip ( cmdline, "BOOT_IMAGE=" );
        cmdline_strip ( cmdline, "initrd=" );
        while ( isspace ( *cmdline ) )
                cmdline++;
        DBGC ( colour, "RUNTIME using command line \"%s\"\n", cmdline );

        /* Prepare and register image */
        cmdline_image.data = virt_to_user ( cmdline );
        cmdline_image.len = strlen ( cmdline );
        if ( cmdline_image.len ) {
                if ( ( rc = register_image ( &cmdline_image ) ) != 0 ) {
                        DBGC ( colour, "RUNTIME could not register command "
                               "line: %s\n", strerror ( rc ) );
                        goto err_register_image;
                }
        }

        /* Drop our reference to the image */
        image_put ( &cmdline_image );

        return 0;

 err_register_image:
        image_put ( &cmdline_image );
 err_alloc_cmdline_copy:
        return rc;
}

/**
 * Initialise initrd
 *
 * @ret rc              Return status code
 */
static int initrd_init ( void ) {
        struct image *image;

        /* Do nothing if no initrd was specified */
        if ( ! initrd_phys ) {
                DBGC ( colour, "RUNTIME found no initrd\n" );
                return 0;
        }
        if ( ! initrd_len ) {
                DBGC ( colour, "RUNTIME found empty initrd\n" );
                return 0;
        }
        DBGC ( colour, "RUNTIME found initrd at [%x,%x)\n",
               initrd_phys, ( initrd_phys + initrd_len ) );

        /* Create initrd image */
        image = image_memory ( "<INITRD>", phys_to_user ( initrd_phys ),
                               initrd_len );
        if ( ! image ) {
                DBGC ( colour, "RUNTIME could not create initrd image\n" );
                return -ENOMEM;
        }

        /* Mark initrd as consumed */
        initrd_phys = 0;

        return 0;
}

/**
 * Initialise command line and initrd
 *
 */
static void runtime_init ( void ) {
        int rc;

        /* Initialise command line */
        if ( ( rc = cmdline_init() ) != 0 ) {
                /* No way to report failure */
                return;
        }

        /* Initialise initrd */
        if ( ( rc = initrd_init() ) != 0 ) {
                /* No way to report failure */
                return;
        }
}

/** Command line and initrd initialisation function */
struct startup_fn runtime_startup_fn __startup_fn ( STARTUP_NORMAL ) = {
        .name = "runtime",
        .startup = runtime_init,
};