Re: stage1_5, How does it work? Plus New Filesystem

[Shaun Savage]

OKUJI Yoshinori wrote:
> 
> Shaun, please post your messages to bug-grub.
> 
> 
> > Compressed Block Device is a linux kernel driver that does demand
> > decompression of the filesystem.  It is not a file system to speak of,
> > it is a block device BUT the partition "image" can have the kernel in
> > it, the stage2 bootloader, the menu.lst, splash screen, .....   It does
> > it own partition managment. this partition has a pseudo file system on
> > it where the content are files.
> >
> > The CBD is designed for use in embedded devices.  It shrinks the
> > filesystem size by 2.5 - 3 times so less storage is needed.

> > For more information see http://www.infomatec.com/cbd
> 
> 
> This explains how GRUB works *usually*, but GRUB is not restricted to
> the usage. Strictly speaking, you can put Stage 1.5 (or Stage 2)
> anywhere you like, and Stage 2 can load a configuration file from
> anywhere on your disks (The configuration file needs not to be put in
> a filesystem). See the Programmer Reference Manual in the GRUB manual,
> for more details.
> 
> > I have attached the CBD files htat I am using.  I also 'hacked' the
> > configure.in and Makefile.in and Makefile.am BUT I am not sure I did the
> > right things. It works, but it makes the stage2/makefile every time.
> 
> You shouldn't modify Makefile.in manually; It's a automatically
> generated file with Automake. Anyway, send a patch to the list, and we
> will suggest a better way or approve the patch.
> 

Could I get some help with the configuration?  I can enclose the source
files
for the CBD.

Shaun

/*
 * This header file defines the ioctls
 * for the CBD DRIVER
 * we use 'i' as "our letter" (c.f. linux/Documentation/ioctl-number.txt)
 */

#ifndef _CBD_H_
#define _CBD_H_

#define CBD_MAJOR 61

#define CBD_LETTER                     'i'
#define CBD_ERASE_SECTION           _IOWR(CBD_LETTER, 1, long *)
#define CBD_INVAL_BUFFERS           _IOWR(CBD_LETTER, 2, long *)
#define CBD_INVAL_PARTITION         _IOWR(CBD_LETTER, 3, long *)
#define CBD_GET_FREE_SECTION        _IOWR(CBD_LETTER, 4, long *)
#define CBD_GET_PARTITION_VERSION   _IOWR(CBD_LETTER, 5, long *)
#define CBD_COMMIT_SECTION          _IOWR(CBD_LETTER, 6, long *)
#define CBD_GET_SIZE                _IOWR(CBD_LETTER, 7, long *)
#define CBD_GET_HWCONFIG            _IOWR(CBD_LETTER, 8, long *)
#define CBD_GET_RAWDEVICE           _IOWR(CBD_LETTER, 9, long *)
#define CBD_NEW_FORMAT              _IOWR(CBD_LETTER, 10, long *)

/*
 * Section Header:
 * 
 * Each section (except BIOS-sections and unintialized sections)
 * starts with a section header:
 */

#define CBD_SECTION_SIZE  0x10000L      /* 64 K */
#define IGF_SECT_HDR_LEN  32    /* we assume section hdrs to be that long! */
#define IGF_SECT_DATA_LEN (CBD_SECTION_SIZE - IGF_SECT_HDR_LEN)
#define CBD_DEV_0_NAME    "/dev/igf0"
#define CBD_MAGIC 0x4c454749
#define CBD_PARTHDR_CRC_START   (2 * sizeof (ulong))
#define DRIVER_VERSION -1
#define CBD_MAX_MINORS 16

/* typedef unsigned long ulong; */
/* typedef unsigned short unsigned short; */
#ifndef uchar

typedef unsigned char uchar; 
#endif

/*  content types */
/*  NONE        nothing */
#define NONE    0x454E4F4E
/*  CLST        cluster map */
#define CLST    0x54534C43
/*  SECT        section map */
#define SECT    0x54434553
/*  KRNL        kernel */
#define KRNL    0x4C4E524B
/*  BOOT        boot */
#define BOOT    0x544F4F42
/*  BOT1        boot1 */
#define BOT1    0x31544F42
/*  BOT2        boot2 */
#define BOT2    0x32544F42
/*  BOT3        boot3 */
#define BOT3    0x33544F42
/*  SPLS        splash */
#define SPLS    0x534C5053
/*  INRD        initrd */
#define INRD    0x44544E49
/*  DICT        dictionary */
#define DICT    0x54434944
/*  MKEY        make public key */
#define MKEY    0x59454B4D
/*  OKEY        oem public key */
#define OKEY    0x59454B4F
/*  RKEY        register public key */
#define RKEY    0x59454B52
/*  SIGN        signature */
#define SIGN    0x4E474953

typedef struct cbd_part_content {
        char    name[4];
        unsigned int    offset;
        unsigned int    length;
        unsigned int    crc;
} cbd_part_content_t; /* struct cbd_part_content */

typedef struct cbd_part_hdr {
        
        unsigned int    magic;                          /* 0 IGEL */
        
        unsigned int    hdr_crc;                        /* 4 checksum */
        
        char    drvver;                         /* 8 driver version */
        uchar   cluster_shift;                  /* 9 cluster size 32k */
        uchar   n_content;                      /* A number of types */
        uchar   cbd_minor;                      /* B minor nimber */

        unsigned short  hdr_len;                        /* C length */
        unsigned short  n_sections;                     /* E number of sections 
*/

        unsigned int    version;                        /* 10 partition version 
*/
        unsigned int    update_count;                   /* 14 sequence */

        unsigned int    n_clusters;                     /* 18 number of cluster 
*/

        unsigned int    offset_section_table;           /* 1C start of section 
table */

        cbd_part_content_t content_table[0];    /* 20 content table */

} cbd_part_hdr_t; /* struct cbd_part_hdr */

/* now comes section table */
/* then comes contents */

#define align(a,b) (((a + b -1)/b) * b)

/* proc data information */
/* size:        total  free */
#define CBD_PROC_SIZE "%d %d"
/* map:         array of status and partition */
/* part:        lines of 
        "part# version update# cluster# section# mounted*/
#define CBD_PROC_PART "%d %x %x %x %x %d"
/* info:        ??? */
/* device:      lines of block devices */
#endif

/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 1996  Erich Boleyn  <address@hidden>
 *  Copyright (C) 2000  Free Software Foundation, Inc.
 *
 *  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
 *  (at your option) 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.
 */

/*
 * Elements of this file were originally from the FreeBSD "biosboot"
 * bootloader file "disk.c" dated 4/12/95.
 *
 * The license and header comments from that file are included here.
 */

/*
 * Mach Operating System
 * Copyright (c) 1992, 1991 Carnegie Mellon University
 * All Rights Reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  address@hidden
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 *
 *      from: Mach, Revision 2.2  92/04/04  11:35:49  rpd
 *      $Id: fsys_ffs.c,v 1.8 2000/04/15 13:39:38 okuji Exp $
 */

#ifdef FSYS_CBD

#include "shared.h"

#include "filesys.h"

#include "defs.h"
#include "dir.h"
#include "fs.h"
#include "cbd.h"

typedef struct part_s {
    unsigned int start;
    unsigned int hdr_len;
    unsigned int n_sections;
    unsigned long version, update_count;
} part_t;


/* used for filesystem map blocks */
static unsigned short section_map[2048];
static part_t part_map[15];
static int n_parts;
static int version, update_count;
static cbd_part_content_t *content;

/* pointer to superblock */
#define SUPERBLOCK ((struct fs *) ( FSYS_BUF + 8192 ))
#define INODE ((struct icommon *) ( FSYS_BUF + 16384 ))
#define MAPBUF ( FSYS_BUF + 24576 )
#define MAPBUF_LEN 8192


static int data_read(cbd_part_content_t *cont, unsigned long foffset, char* 
buf,int len)
{
    int rslt;
    part_t *ppart = &part_map[0];
    unsigned long sector,offset,section;
    int orcnt, tioncnt;

    section = ppart->start;
    offset = foffset + cont->offset;
    sector = (section<<7) + (offset >> 9);
    offset = offset & 0x01ff;
    orcnt  = (len + 511)>> 9;
    tioncnt = (orcnt + 127 )>>7;

    rslt = devread(sector,offset,len, buf);
    if(rslt <1)
        return 0;

    //    memcpy(buf,FSYS_BUF,len);
    filepos += len;
    return len;
}


int
cbd_mount (void)
{
    unsigned long start_sector;
    unsigned int section=0, part_size;
    cbd_part_hdr_t hdr;
    part_t *ppart;
    
    start_sector=0;
    n_parts=0;
    part_size = part_length>>7;
    content = NULL;

    if(part_size > 1024)
        return 0;

    for(section=1;section < part_size;section++) {
        section_map[section] = 0;
    }

    for(section=1;(!start_sector) && (section < part_size); section++) {
        if(section_map[section])
            continue;           /* used already */
        devread(section<<7,0,0x20,(char*)&hdr);
        if(hdr.magic != CBD_MAGIC)
            continue;
        /* found something */
        if(hdr.drvver > -1)
            continue;           /* first check */
        
        ppart = &part_map[n_parts];
        section_map[section] =  n_parts++;

        ppart->start = section;
        ppart->n_sections = hdr.n_sections;
        ppart->version = version = hdr.version;
        ppart->hdr_len = hdr.hdr_len;
        ppart->update_count = update_count = hdr.update_count;

        if(hdr.cbd_minor != 1)
            continue;
        start_sector = section<<7;
    }
    if(!start_sector)
        return 0;
    return 1;
}

int
cbd_read (char *buf, int len)
{

    if((content == NULL) || (filemax == 0)) 
        return 0;
    if(len==0)
        return 1;
    
    return data_read(content, filepos, buf, len);
}


int
cbd_dir (char *dirname)
{
    int i;
    part_t *ppart = &part_map[0];
    cbd_part_hdr_t *hdr = (cbd_part_hdr_t*)FSYS_BUF;
    unsigned short *section_tbl;

    filemax = 0;
    devread(ppart->start<<7,0,ppart->hdr_len,(char*)FSYS_BUF);
    for(i=0 ; i< hdr->hdr_len ; i++) {
        if((*(int*)hdr->content_table[i].name) == *(int*)&dirname[1] ) {
            content = &hdr->content_table[i];
            filepos = 0;
            filemax = content->length;
            section_tbl = (unsigned short*) ((char*)hdr + 
hdr->offset_section_table);
            for( i=0 ; i < hdr->n_sections ; i++) {
                section_map[i] = section_tbl[i];
            }
            return 1;
        }
    }
    return 0;
}

void
cbd_close(void)
{
}


int
cbd_embed (int *start_sector, int needed_sectors)
{
    unsigned int section=0;
    cbd_part_hdr_t hdr;
    part_t *ppart;
    
    start_sector=0;
    n_parts=0;

    for(section=1;;section++) {
        section_map[section] = 0;
    }

    for(section=1;!start_sector; section++) {
        if(section_map)
            continue;           /* used already */
        devread(section<<7,0,0x20,(char*)&hdr);
        if(hdr.magic != CBD_MAGIC)
            continue;
        /* found something */
        if(hdr.drvver > -1)
            continue;           /* first check */
        
        ppart = &part_map[n_parts];
        section_map[section] =  n_parts++;

        ppart->start = section;
        ppart->n_sections = hdr.n_sections;
        ppart->version = version = hdr.version;
        ppart->update_count = update_count = hdr.update_count;

        if(hdr.cbd_minor != 1)
            continue;
        *start_sector = section<<7;
    }
    return 1;
}

#endif /* FSYS_CBD */