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/* activate.c - Simple partition activator */
/* Copyright 1992-1995 Werner Almesberger. See file COPYING for details. */
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#define PART_BEGIN 0x1be
#define PART_NUM 4
#define PART_SIZE 16
#define PART_ACTIVE 0x80
#define PART_INACTIVE 0
static void die(char *fmt,...)
{
va_list ap;
va_start(ap,fmt);
vfprintf(stderr,fmt,ap);
va_end(ap);
fprintf(stderr,"\n");
exit(1);
}
int main(int argc,char **argv)
{
struct stat st;
int fd,number,count;
unsigned char flag;
if (argc != 2 && argc != 3) {
fprintf(stderr,"usage: %s device [ partition ]\n",argv[0]);
fprintf(stderr," i.e. %s /dev/hda 2\n",argv[0]);
exit(1);
}
if ((fd = open(argv[1],argc == 2 ? O_RDONLY : O_WRONLY)) < 0)
die("open %s: %s",argv[1],strerror(errno));
if (fstat(fd,&st) < 0) die("stat %s: %s",argv[1],strerror(errno));
if (!S_ISBLK(st.st_mode)) die("%s: not a block device",argv[1]);
if (argc == 2) {
for (count = 1; count <= PART_NUM; count++) {
if (lseek(fd,PART_BEGIN+(count-1)*PART_SIZE,0) < 0)
die("lseek: %s",strerror(errno));
if (read(fd,&flag,1) != 1) die("read: %s",strerror(errno));
if (flag == PART_ACTIVE) {
printf("%s%d\n",argv[1],count);
exit(0);
}
}
die("No active partition found on %s",argv[1]);
}
number = atoi(argv[2]);
if (number < 1 || number > 4)
die("%s: not a valid partition number (1-4)",argv[2]);
for (count = 1; count <= PART_NUM; count++) {
if (lseek(fd,PART_BEGIN+(count-1)*PART_SIZE,0) < 0)
die("lseek: %s",strerror(errno));
flag = count == number ? PART_ACTIVE : PART_INACTIVE;
if (write(fd,&flag,1) != 1) die("write: %s",strerror(errno));
}
return 0;
}
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