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
  36 struct 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
  69 typedef 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
  85 int 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