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