probe.c

linux 的引导程序源码The Microsoft&reg Windows&reg Software Development Kit (SDK) provides the documentation

   struct disk_geom geom;
   
   for (hd=0; hd<0x81; hd+=0x80)
   for (d=0; d<16; d++) {
      dr = d+hd;
      if (get_geom(dr, &geom)==0) {
         if (dr==0x80) printf("\nBIOS reports %d drive%s\n", (int) geom.n_disks,
                                      (int)geom.n_disks==1 ? "" : "s");
      	 print_geom(dr, geom);
      }
   }
}


/* print disk drive geometry information for a particular drive */
static void do_geom(char *bios)
{
    int dr;
    struct disk_geom geom;

#if 0    
    dr = my_atoi(bios);
#endif
    dr = to_number(bios);
    if (get_geom(dr, &geom)==0) print_geom(dr, geom);
    else printf("Unrecognized BIOS device code 0x%02x\n", dr);
    
}


/* print an individual partition table entry */
static void print_pt(int index, struct partition pt)
{
    char bt[4], *ty, start[32], end[32], type[8];
    char x;
    int i;
    
    for (x=i=0; i<sizeof(pt); i++) x |= ((char*)&pt)[i];
    if (!x) {
    	printf("%4d\t\t\t     ** empty **\n", index);
    	return;
    }
    strcpy(bt,"   ");
    sprintf(type, "0x%02x", (int)pt.sys_ind);
    sprintf(start, "%4d:%d:%d",
    	(int)pt.cyl+((pt.sector&0xC0)<<2),
    	(int)pt.head,
    	(int)pt.sector & 0x3f );
    sprintf(end, "%4d:%d:%d",
    	(int)pt.end_cyl+((pt.end_sector&0xC0)<<2),
    	(int)pt.end_head,
    	(int)pt.end_sector & 0x3f );
    ty = type;
    if (pt.boot_ind==0x80) bt[1]='*';
    else if (pt.boot_ind==0) ; /* do nothing */
    else {
    	sprintf(bt+1,"%02x", (int)pt.boot_ind);
    }
    for (i=0; ptab[i].name; i++) {
	if (ptab[i].type == pt.sys_ind) {
	    ty = ptab[i].name;
	    break;
	} else if ((ptab[i].type|ptab[i].hide) == pt.sys_ind) {
	    bt[0] = 'H';
	    ty = ptab[i].name;
	    break;
	}
    }
    printf("%4d%18s%5s%11s%14s%12u%12u\n", index, ty, bt,
    	start, end, pt.start_sect, pt.nr_sects);
}


/* partition table display */
static void do_table(char *part)
{
    int fd, i;
    struct partition pt [PART_MAX];
    unsigned int second, base;
    unsigned short boot_sig;
    
    if (!strncmp(part, "/dev/", 5)) {
	if (strncmp(part+5, "md", 2) && isdigit(part[strlen(part)-1]) )
	    die("Not a device: '%s'", part);
	fd = open(part, O_RDONLY);
    } else
	fd = -1;
    if (fd<0) die("Unable to open '%s'", part);
    if (lseek(fd, PART_TABLE_OFFSET, SEEK_SET)<0) die("lseek failed");
    if (read(fd, pt, sizeof(pt)) != sizeof(pt)) die("read pt failed");
    if ( read(fd, &boot_sig, sizeof(boot_sig)) != sizeof(boot_sig)  ||
	boot_sig != BOOT_SIGNATURE ) die("read boot signature failed");
    {
	if (lseek(fd, MAX_BOOT_SIZE+2, SEEK_SET)<0) die("lseek s/n failed");
	if (read(fd, &second, sizeof(second)) != sizeof(second))
	    die("read s/n failed");
	printf(" S/N = %08X\n", second);
    }
    printf("%s\n", phead);
    second=base=0;
    for (i=0; i<PART_MAX; i++) {
	print_pt(i+1, pt[i]);
	if (is_extd_part(pt[i].sys_ind)) {
	    if (!base) base = pt[i].start_sect;
	    else die("invalid partition table: second extended partition found");
	}
    }
    i=5;
    while (verbose>0 && base) {
        if (llseek(fd, LLSECTORSIZE*(base+second) + PART_TABLE_OFFSET, SEEK_SET) < 0)
            die("secondary llseek failed");
	if (read(fd, pt, sizeof(pt)) != sizeof(pt)) die("secondary read pt failed");
	if ( read(fd, &boot_sig, sizeof(boot_sig)) != sizeof(boot_sig)  ||
	    boot_sig != BOOT_SIGNATURE ) die("read second boot signature failed");
        print_pt(i++, pt[0]);
        if (is_extd_part(pt[1].sys_ind)) second=pt[1].start_sect;
        else base = 0;
    }
        
    close(fd);
}


/* list partition change-rules */
static void do_cr_pr(void)
{
    CHANGE_RULE *cr;
    
    cr = change_rules;
    printf("\t\tType Normal Hidden\n");
    if (!cr) printf("\t **** no change-rules defined ****\n");
    while (cr) {
	printf ("%20s  0x%02x  0x%02x\n", cr->type, (int)cr->normal, (int)cr->hidden);
	cr = cr->next;
    }
}

#if VIDEO
static int egamem;
static int mode, col, row, page;

int get_video(void)	/* return -1 on error, or adapter type [0..7] */
{
    int adapter = 0;    /* 0=unknown, 1=MDA,HGC, 2=CGA, 3=EGA, 4=MCGA, 5=VGA,
		    			 6=VESA (640), 7=VESA (800) */
    int okay = 1;
    int monitor;
        
    if(fetch()) return -1;

    if ((okay=buf.s.vid)) {
    /* get current video mode */
    /* reg.eax = 0x0F00;		*/
	if (verbose >= 2)
	    printf("get video mode\n");
	mode = buf.s.v.vid0F.al;
	col = buf.s.v.vid0F.ah;
	page = buf.s.v.vid0F.bh;
	row = buf.s.v.vid0F.bl + 1;
	if (mode==7) {
	    adapter=1;
	    row = 25;
	    okay = 0;
	} else if (col<80) {
	    adapter=2;
	    okay=0;
	} else adapter=2;	/* at least CGA */
    }
    if (okay>=2) {
#if 1
    /* determine video adapter type */
    /*    reg.eax = 0x1200;	  call valid on EGA/VGA */
    /*    reg.ebx = 0xFF10;				*/
	if (verbose >= 2)
	    printf("determine adapter type\n");
	if ((unsigned)(monitor = buf.s.v.vid12.bh) <= 1U)  {
    	    adapter = 3; /* at least EGA */
	    egamem = buf.s.v.vid12.bl;
	}
	else {
	    okay = 0;
	}
    }
#endif
    if (okay>=2) {
	/* check for VGA */
    	/* reg.eax = 0x1A00;	   get display combination */
    	if (verbose >= 2)
	    printf("get display combination\n");
	if ( buf.s.v.vid1A.al==0x1A ) {
    	    monitor = (buf.s.v.vid1A.bx >> ((verbose>=3)*8) ) & 0xFF;
    	    switch (monitor) {
    	      case 1:
    	        adapter = 1;
    	        break;
    	      case 2:
    	        adapter = 2;
    	        break;
	      case 7:
	      case 8:
	        adapter = 5;	/* VGA */
    	        break;
    	      case 0xA:
    	      case 0xB:
    	      case 0xC:
    	        adapter = 4;	/* MCGA */
    	        break;
    	      default:
    	        okay = 0;
    	        break;
    	    }
    	} else {
    	    okay = 0;
    	}
    }
    if (okay>=3 && adapter==5) {
	/* check for VESA extensions */
    	if (verbose >= 2)
	    printf("check VESA present\n");
	    
	if ((buf.s.v.vid4F00.ax == 0x4f) && strncmp("VESA", buf.s.v.vid4F00.sig, 4)==0)  adapter++;
	
	if (adapter > 5) {
	    /* reg.eax = 0x4f01;
	       reg.ecx = 0x0101;	   640x480x256 */
	    if ((buf.s.v.vid101.ax == 0x4f) && (buf.s.v.vid101.bits & 0x19) == 0x19) adapter ++;
	    else adapter--;
	}
	if (adapter > 6) {
	    /* reg.eax = 0x4f01;
	       reg.ecx = 0x0103;	   800x600x256 */
	    if ((buf.s.v.vid103.ax == 0x4f) && (buf.s.v.vid103.bits & 0x19) == 0x19) ;
	    else adapter--;
	}
    }
    if (verbose>=2)
    	printf ("mode = 0x%02x,  columns = %d,  rows = %d,  page = %d\n\n",
    		       mode, col, row, page);
    
    return adapter;
}

/* print VGA/VESA mode information */
void do_video(void)
{
static char *display[] = { "unknown", "MDA", "CGA", "EGA", 
		"MCGA", "VGA", "VGA/VESA", "VGA/VESA" };
    int adapter; /* 0=unknown, 1=MDA,HGC, 2=CGA, 3=EGA, 4=MCGA, 5=VGA,
    			 6=VESA (640), 7=VESA (800) */

    adapter = get_video();

    if(adapter<0) {
        printf("No video mode information is available.\n");
        return;
    }
    
    if (verbose>=1)
    	printf ("mode = 0x%02x,  columns = %d,  rows = %d,  page = %d\n\n",
    		       mode, col, row, page);

    printf("%s adapter:\n\n", display[adapter]);
    if (adapter < 3 || (adapter == 3 && egamem < 1) ) {
        printf("No graphic modes are supported\n");
    } else {
	if (adapter != 4)
	    printf("    640x350x16    mode 0x0010\n");
	if (adapter >= 5) {
	    printf("    640x480x16    mode 0x0012\n\n");
	    printf("    320x200x256   mode 0x0013\n");
	}
	if (adapter >= 6)
	    printf("    640x480x256   mode 0x0101\n");
	if (adapter >= 7)
	    printf("    800x600x256   mode 0x0103\n");
    }

}
#endif

/* entry from lilo.c for the '-T' (tell) switch */
void probe_tell (char *cmd)
{
    struct Probes *pr = list;
    int n;
    char *arg;
    
    if (!(verbose>0)) printf("\n");
    for (; pr->cmd; pr++) {
	n = strlen(pr->cmd);
	arg = NULL;
	if (pr->cmd[n-1] == '=') arg = cmd+n;
	if (!strncasecmp(cmd, pr->cmd, n)) {
	    pr->prc(arg);
	    printf("\n");
	    exit(0);
	}
    }
    printf("Unrecognized option to '-T' flag\n");
    do_help();
    printf("\n");
    exit(1);
}


int bios_max_devs(void)
{
    struct disk_geom geom;
    int i;
    
    if (!fetch() && !get_geom(0x80, &geom)) {
	i = (buf.s.disk & 0x7f) + 1;
	if (geom.n_disks == i) return i;
    }
    return BIOS_MAX_DEVS;    
}

#ifdef DEBUG
static void dump_pt(unsigned char *pt)
{
    int i, j;
    for (j=0; j<4; j++) {
	for (i=0; i<16; i++) {
	    printf(" %02X", (int)(*pt++));
	}
	printf("\n");
    }
    printf("\n");
}
#endif

/* 
 *  return the bios device code of the disk, based on the geometry
 * 	match with the probe data
 *   side effect is to place the device code in geo->device
 * return -1 if indeterminate
 */
int bios_device(GEOMETRY *geo, int device)
{
    int bios1, bios, match, fd;
    int mbios[BD_MAX_HARD];
    struct disk_geom bdata;
    DEVICE dev;
    unsigned char part[PART_TABLE_SIZE];
    unsigned char extra[8];
    int serial;
    
        
    if (fetch()) return -1;
    
    if (verbose>=3) printf("bios_dev:  device %04X\n", device);
    
    match = 0;
    bios1 = -1;		/* signal error */
    for (bios=0x80; bios<=buf.s.disk; bios++) {
	mbios[bios-0x80] = 0;
	if (get_geom(bios, &bdata)) break;
	if (geo->cylinders == bdata.n_cyl &&
	    geo->heads == bdata.n_head &&
	    geo->sectors == bdata.n_sect) {
	    	match++;
	    	mbios[bios-0x80] = bios1 = bios;
	}
    }
    if (match == 1) {
    	if (verbose>=2) printf("bios_dev: match on geometry alone (0x%02X)\n",
    		bios1);
	return (geo->device = bios1);
    }

    device &= D_MASK(device);	/* mask to primary device */
    fd = dev_open(&dev,device,O_RDONLY);
    if (verbose>=3) printf("bios_dev:  masked device %04X, which is %s\n", 
    			device, dev.name);
    if (lseek(fd, PART_TABLE_OFFSET-8, SEEK_SET)!=PART_TABLE_OFFSET-8)
	die("bios_device: seek to partition table - 8");
    if (read(fd,extra,sizeof(extra))!= sizeof(extra))
	die("bios_device: read partition table - 8");
    serial = *(int*)(extra+2);
    if (lseek(fd, PART_TABLE_OFFSET, SEEK_SET)!=PART_TABLE_OFFSET)
	die("bios_device: seek to partition table");
    if (read(fd,part,sizeof(part))!= sizeof(part))
	die("bios_device: read partition table");
    dev_close(&dev);

#ifdef DEBUG
    if (verbose>=4) {
        printf("serial number = %08X\n", serial);
        dump_pt(part);
    }
#endif

    if (verbose>=3) printf("bios_dev: geometry check found %d matches\n", match);
    match = 0;
    bios1 = -1;
    while (--bios >= 0x80) {
	get_geom(bios, &bdata);
	if (verbose>=4) {
		printf("bios_dev: (0x%02X)  S/N=%08X  *PT=%08X\n",
			bios, bdata.serial_no, (int)bdata.pt);
#ifdef DEBUG
		dump_pt((void*)bdata.pt);
#endif
	}
	if (!memcmp(part,bdata.pt,sizeof(part)) &&
		!(bdata.serial_no && serial!=bdata.serial_no)
	   ) {
	    match++;
	    bios1 = bios;
	}
    }
    if (verbose>=2) printf("bios_dev: PT match found %d match%s (0x%02X)\n",
    		match, match==1 ? "" : "es", bios1);

    if (match != 1) bios1 = -1;
    else {	/* match == 1 */
	get_geom(bios1, &bdata);
	if (  (geo->sectors && geo->sectors!=bdata.n_sect)  ||
	       (geo->heads && geo->heads!=bdata.n_head)  )  {
	    unsigned long nblocks = geo->cylinders * geo->heads * geo->sectors;

	    if (!nowarn && !(warned[bios1-0x80]&2) ) {
		fprintf(errstd,"Warning: Kernel & BIOS return differing head/sector geometries for device 0x%02X\n", bios1);
		show_geom("Kernel", geo->cylinders, geo->heads, geo->sectors);
		show_geom("  BIOS", bdata.n_cyl, bdata.n_head, bdata.n_sect);
		warned[bios1-0x80] |= 2;
	    }
#if 1
	    geo->sectors = bdata.n_sect;
	    geo->heads = bdata.n_head;
	    if (bdata.n_total_blocks > nblocks) nblocks = bdata.n_total_blocks;
	    geo->cylinders = nblocks / (bdata.n_head*bdata.n_sect);
#endif
	}
    }

    return (geo->device = bios1);
}


static void do_bitmap(char *file)
{
    printf("Color, Positioning, and Timer information for file:  %s\n", file);
    printf("...<unimplemented>...\n");
}