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