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