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/*
* This file contains some code to guess where we have to load the
* RAM image device from, if started from CD. (In this case it's hard
* to tell where this is without diving into BIOS heuristics.)
*
* There is some nasty hard-codery in here ( MINIX cd label) that can be
* improved on.
*
* Changes:
* Jul 14, 2005 Created (Ben Gras)
* Feb 10, 2006 Changed into a standalone program (Philip Homburg)
* May 25, 2015 Installation CD overhaul (Jean-Baptiste Boric)
*/
#define CD_SECTOR 2048
#define SUPER_OFF 1024
#define AT_MINORS 8
#define MAGIC_OFF 24
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
int main(void)
{
const int probelist[AT_MINORS] = { 2, 3, 1, 0, 6, 7, 5, 4 };
int controller, disk, r, fd;
off_t pos;
char name[] = "/dev/c0dX";
char pvd[CD_SECTOR];
for(controller = 0; controller <= 1; controller++) {
name[6] = '0' + controller;
for(disk = 0; disk < AT_MINORS; disk++) {
name[8]= '0' + probelist[disk];
fprintf(stderr, "Trying %s \r", name);
fflush(stderr);
fd = open(name, O_RDONLY);
if ((fd < 0) && (errno != ENXIO)) {
fprintf(stderr, "open '%s' failed: %s\n",
name, strerror(errno));
continue;
}
/* Try to read PVD. */
pos = lseek(fd, 16*CD_SECTOR, SEEK_SET);
if (pos != 16*CD_SECTOR) {
close(fd);
continue;
}
r = read(fd, pvd, sizeof(pvd));
close(fd);
if (r != sizeof(pvd)) {
continue;
}
/* Check PVD ID. */
if (pvd[0] != 1 || pvd[1] != 'C' || pvd[2] != 'D' ||
pvd[3] != '0' || pvd[4] != '0' || pvd[5] != '1' ||
pvd[6] != 1 ||
strncmp(pvd + 40, "MINIX", 5) != 0) {
continue;
}
fprintf(stderr, "\nFound.\n");
printf("%s\n", name);
return 0;
}
}
fprintf(stderr, "\nNot found.\n");
return 1;
}
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