1 /* Based on original installboot from MINIX 3. 2 * 3 * installboot 3.0 - Make a device bootable Author: Kees J. Bot 4 * 21 Dec 1991 5 */ 6 7 #define _POSIX_SOURCE 1 8 #define _MINIX 1 9 10 #include <stdio.h> 11 #include <stdlib.h> 12 #include <string.h> 13 #include <errno.h> 14 #include <fcntl.h> 15 #include <unistd.h> 16 #include <dirent.h> 17 #include <sys/stat.h> 18 19 #define BOOTBLOCK 0 /* Of course */ 20 #define BOOT_BLOCK_SIZE 1024 21 #define SIGNATURE 0xAA55 /* Boot block signature. */ 22 #define SIGPOS 510 /* Where to put signature word. */ 23 #define PARTPOS 446 /* Offset to the partition table in a master 24 * boot block. 25 */ 26 27 28 static int rawfd; /* File descriptor to open device. */ 29 static const char *rawdev; /* Name of device. */ 30 31 32 static void report(const char *label) 33 /* installboot: label: No such file or directory */ 34 { 35 fprintf(stderr, "installboot: %s: %s\n", label, strerror(errno)); 36 } 37 38 static void fatal(const char *label) 39 { 40 report(label); 41 exit(1); 42 } 43 44 static void bread(FILE *f, char *name, void *buf, size_t len) 45 /* Read len bytes. Don't dare return without them. */ 46 { 47 if (len > 0 && fread(buf, len, 1, f) != 1) { 48 if (ferror(f)) fatal(name); 49 fprintf(stderr, "installboot: Unexpected EOF on %s\n", name); 50 exit(1); 51 } 52 } 53 54 static void readblock(off_t blk, char *buf, int block_size) 55 /* For rawfs, so that it can read blocks. */ 56 { 57 int n; 58 59 if (lseek(rawfd, blk * block_size, SEEK_SET) < 0 60 || (n= read(rawfd, buf, block_size)) < 0 61 ) fatal(rawdev); 62 63 if (n < block_size) { 64 fprintf(stderr, "installboot: Unexpected EOF on %s\n", rawdev); 65 exit(1); 66 } 67 } 68 69 static void writeblock(off_t blk, const char *buf, int block_size) 70 /* Add a function to write blocks for local use. */ 71 { 72 if (lseek(rawfd, blk * block_size, SEEK_SET) < 0 73 || write(rawfd, buf, block_size) < 0 74 ) fatal(rawdev); 75 } 76 77 78 /* A temp stub until fdisk is ported to MINIX */ 79 void install_master(const char *device, char *masterboot, char **guide) 80 /* Booting a hard disk is a two stage process: The master bootstrap in sector 81 * 0 loads the bootstrap from sector 0 of the active partition which in turn 82 * starts the operating system. This code installs such a master bootstrap 83 * on a hard disk. If guide[0] is non-null then the master bootstrap is 84 * guided into booting a certain device. 85 */ 86 { 87 FILE *masf; 88 unsigned long size; 89 static char buf[_MAX_BLOCK_SIZE]; 90 91 /* Open device. */ 92 if ((rawfd= open(rawdev= device, O_RDWR)) < 0) fatal(device); 93 94 /* Open the master boot code. */ 95 if ((masf= fopen(masterboot, "r")) == NULL) fatal(masterboot); 96 97 size= PARTPOS; 98 99 /* Read the master boot block, patch it, write. */ 100 readblock(BOOTBLOCK, buf, BOOT_BLOCK_SIZE); 101 102 memset(buf, 0, PARTPOS); 103 (void) bread(masf, masterboot, buf, size); 104 105 /* Install signature. */ 106 buf[SIGPOS+0]= (SIGNATURE >> 0) & 0xFF; 107 buf[SIGPOS+1]= (SIGNATURE >> 8) & 0xFF; 108 109 writeblock(BOOTBLOCK, buf, BOOT_BLOCK_SIZE); 110 } 111 112 int isoption(const char *option, const char *test) 113 /* Check if the option argument is equals "test". Also accept -i as short 114 * for -image, and the special case -x for -extract. 115 */ 116 { 117 if (strcmp(option, test) == 0) return 1; 118 if (option[0] != '-' && strlen(option) != 2) return 0; 119 if (option[1] == test[1]) return 1; 120 if (option[1] == 'x' && test[1] == 'e') return 1; 121 return 0; 122 } 123