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/*
* abootconf.c
*
* This file is part of aboot, the SRM bootloader for Linux/Alpha
* Copyright (C) 1996 Linus Torvalds, David Mosberger, and Michael Schwingen.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/fcntl.h>
#include <config.h>
const char * prog_name;
int
main (int argc, char ** argv)
{
unsigned long sector[512 / sizeof(unsigned long)];
off_t aboot_pos;
size_t nbytes;
long part = -1;
int disk, i;
prog_name = argv[0];
if (argc != 2 && argc != 3) {
fprintf(stderr, "usage: %s device [partition]\n", prog_name);
exit(1);
}
if (argc > 2) {
errno = 0;
part = strtol(argv[2], 0, 10);
if (errno == ERANGE) {
fprintf(stderr, "%s: bad partition number %s\n",
prog_name, argv[2]);
exit(1);
}
}
disk = open(argv[1], part < 0 ? O_RDONLY : O_RDWR);
if (disk < 0) {
perror(argv[1]);
exit(1);
}
nbytes = read(disk, sector, sizeof(sector));
if (nbytes != sizeof(sector)) {
if ((long) nbytes < 0) {
perror("read");
} else {
fprintf(stderr, "%s: short read\n", prog_name);
}
exit(1);
}
aboot_pos = sector[61] * 512;
if (lseek(disk, aboot_pos, SEEK_SET) != aboot_pos) {
perror("lseek");
exit(1);
}
nbytes = read(disk, sector, sizeof(sector));
if (nbytes != sizeof(sector)) {
if ((long) nbytes < 0) {
perror("read");
} else {
fprintf(stderr, "%s: short read\n", prog_name);
}
exit(1);
}
for (i = 0; i < (int) (sizeof(sector)/sizeof(sector[0])); ++i) {
if (sector[i] == ABOOT_MAGIC)
break;
}
if (i >= (int) (sizeof(sector)/sizeof(sector[0]))) {
fprintf(stderr, "%s: could not find aboot on disk %s\n",
prog_name, argv[1]);
exit(1);
}
if (part < 0) {
printf("aboot.conf partition currently set to %ld\n",
sector[i + 1]);
exit(0);
}
if (lseek(disk, aboot_pos, SEEK_SET) != aboot_pos) {
perror("lseek");
exit(1);
}
sector[i + 1] = atoi(argv[2]);
nbytes = write(disk, sector, sizeof(sector));
if (nbytes != sizeof(sector)) {
if ((long) nbytes < 0) {
perror("write");
} else {
fprintf(stderr, "%s: short write\n", prog_name);
}
exit(1);
}
return 0;
}
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