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/*
* fstype.c
*
* Copyright (C) 2001 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#include <stdio.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <fcntl.h>
#include <sys/types.h>
#include "fsck.h"
struct fs_magic {
const char *fs_name;
int offset;
int len;
const char *magic;
};
struct fs_magic type_array[] = {
{ "ext2", 1024+56, 2, "\123\357" },
{ "minix", 1040, 2, "\177\023" },
{ "minix", 1040, 2, "\217\023" },
{ "minix", 1040, 2, "\150\044" },
{ "minix", 1040, 2, "\170\044" },
{ "xfs", 0, 4, "XFSB" },
{ 0, 0, 0, 0 }
};
const char *identify_fs(const char *fs_name)
{
char buf[2048];
struct fs_magic *p;
int fd;
fd = open(fs_name, O_RDONLY);
if (fd < 0)
return NULL;
if (lseek(fd, 0, SEEK_SET) < 0)
return NULL;
if (read(fd, buf, sizeof(buf)) != sizeof(buf))
return NULL;
for (p = type_array; p->fs_name; p++) {
if (memcmp(p->magic, buf+p->offset, p->len) == 0)
return p->fs_name;
}
return NULL;
}
#ifdef TEST_PROGRAM
int main(int argc, char **argv)
{
const char *type;
if (argc != 2) {
fprintf(stderr, "Usage: %s device\n", argv[0]);
exit(1);
}
type = identify_fs(argv[1]);
printf("%s is a %s filesystem\n", argv[1], type);
return (0);
}
#endif
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