LXR linux/arch/alpha/boot/tools/mkbb.c

   1/* This utility makes a bootblock suitable for the SRM console/miniloader */
   2
   3/* Usage:
   4 *      mkbb <device> <lxboot>
   5 *
   6 * Where <device> is the name of the device to install the bootblock on,
   7 * and <lxboot> is the name of a bootblock to merge in.  This bootblock
   8 * contains the offset and size of the bootloader.  It must be exactly
   9 * 512 bytes long.
  10 */
  11
  12#include <fcntl.h>
  13#include <unistd.h>
  14#include <stdlib.h>
  15#include <stdio.h>
  16
  17/* Minimal definition of disklabel, so we don't have to include
  18 * asm/disklabel.h (confuses make)
  19 */
  20#ifndef MAXPARTITIONS
  21#define MAXPARTITIONS   8                       /* max. # of partitions */
  22#endif
  23
  24#ifndef u8
  25#define u8 unsigned char
  26#endif
  27
  28#ifndef u16
  29#define u16 unsigned short
  30#endif
  31
  32#ifndef u32
  33#define u32 unsigned int
  34#endif
  35
  36struct disklabel {
  37    u32 d_magic;                                /* must be DISKLABELMAGIC */
  38    u16 d_type, d_subtype;
  39    u8  d_typename[16];
  40    u8  d_packname[16];
  41    u32 d_secsize;
  42    u32 d_nsectors;
  43    u32 d_ntracks;
  44    u32 d_ncylinders;
  45    u32 d_secpercyl;
  46    u32 d_secprtunit;
  47    u16 d_sparespertrack;
  48    u16 d_sparespercyl;
  49    u32 d_acylinders;
  50    u16 d_rpm, d_interleave, d_trackskew, d_cylskew;
  51    u32 d_headswitch, d_trkseek, d_flags;
  52    u32 d_drivedata[5];
  53    u32 d_spare[5];
  54    u32 d_magic2;                               /* must be DISKLABELMAGIC */
  55    u16 d_checksum;
  56    u16 d_npartitions;
  57    u32 d_bbsize, d_sbsize;
  58    struct d_partition {
  59        u32     p_size;
  60        u32     p_offset;
  61        u32     p_fsize;
  62        u8      p_fstype;
  63        u8      p_frag;
  64        u16     p_cpg;
  65    } d_partitions[MAXPARTITIONS];
  66};
  67
  68
  69typedef union __bootblock {
  70    struct {
  71        char                    __pad1[64];
  72        struct disklabel        __label;
  73    } __u1;
  74    struct {
  75        unsigned long           __pad2[63];
  76        unsigned long           __checksum;
  77    } __u2;
  78    char                bootblock_bytes[512];
  79    unsigned long       bootblock_quadwords[64];
  80} bootblock;
  81
  82#define bootblock_label         __u1.__label
  83#define bootblock_checksum      __u2.__checksum
  84
  85int main(int argc, char ** argv)
  86{
  87    bootblock           bootblock_from_disk;
  88    bootblock           bootloader_image;
  89    int                 dev, fd;
  90    int                 i;
  91    int                 nread;
  92
  93    /* Make sure of the arg count */
  94    if(argc != 3) {
  95        fprintf(stderr, "Usage: %s device lxboot\n", argv[0]);
  96        exit(0);
  97    }
  98
  99    /* First, open the device and make sure it's accessible */
 100    dev = open(argv[1], O_RDWR);
 101    if(dev < 0) {
 102        perror(argv[1]);
 103        exit(0);
 104    }
 105
 106    /* Now open the lxboot and make sure it's reasonable */
 107    fd = open(argv[2], O_RDONLY);
 108    if(fd < 0) {
 109        perror(argv[2]);
 110        close(dev);
 111        exit(0);
 112    }
 113
 114    /* Read in the lxboot */
 115    nread = read(fd, &bootloader_image, sizeof(bootblock));
 116    if(nread != sizeof(bootblock)) {
 117        perror("lxboot read");
 118        fprintf(stderr, "expected %zd, got %d\n", sizeof(bootblock), nread);
 119        exit(0);
 120    }
 121
 122    /* Read in the bootblock from disk. */
 123    nread = read(dev, &bootblock_from_disk, sizeof(bootblock));
 124    if(nread != sizeof(bootblock)) {
 125        perror("bootblock read");
 126        fprintf(stderr, "expected %zd, got %d\n", sizeof(bootblock), nread);
 127        exit(0);
 128    }
 129
 130    /* Swap the bootblock's disklabel into the bootloader */
 131    bootloader_image.bootblock_label = bootblock_from_disk.bootblock_label;
 132
 133    /* Calculate the bootblock checksum */
 134    bootloader_image.bootblock_checksum = 0;
 135    for(i = 0; i < 63; i++) {
 136        bootloader_image.bootblock_checksum += 
 137                        bootloader_image.bootblock_quadwords[i];
 138    }
 139
 140    /* Write the whole thing out! */
 141    lseek(dev, 0L, SEEK_SET);
 142    if(write(dev, &bootloader_image, sizeof(bootblock)) != sizeof(bootblock)) {
 143        perror("bootblock write");
 144        exit(0);
 145    }
 146
 147    close(fd);
 148    close(dev);
 149    exit(0);
 150}
 151
 152
 153