1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
|
/*
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <phk@login.dknet.dk> wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
* ----------------------------------------------------------------------------
*
* $Id: write_mfs_in_kernel.c,v 1.3 1997/02/22 14:10:31 peter Exp $
*
* This program patches a filesystem into a kernel made with MFS_ROOT
* option.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <ufs/ffs/fs.h>
static int force = 0; /* don't check for zeros, may corrupt kernel */
int
main(int argc, char **argv)
{
unsigned char *buf_kernel, *buf_fs, *p,*q, *prog;
int fd_kernel, fd_fs, ch, errs=0;
struct stat st_kernel, st_fs;
u_long l;
prog= *argv;
while ((ch = getopt(argc, argv, "f")) != EOF)
switch(ch) {
case 'f':
force = 1 - force;
break;
default:
errs++;
}
argc -= optind;
argv += optind;
if (errs || argc != 2) {
fprintf(stderr,"Usage:\n\t%s [-f] kernel fs\n", prog);
exit(2);
}
--argv; /* original prog did not use getopt(3) */
fd_kernel = open(argv[1],O_RDWR);
if (fd_kernel < 0) { perror(argv[1]); exit(2); }
fstat(fd_kernel,&st_kernel);
fd_fs = open(argv[2],O_RDONLY);
if (fd_fs < 0) { perror(argv[2]); exit(2); }
fstat(fd_fs,&st_fs);
buf_kernel = malloc(st_kernel.st_size);
if (!buf_kernel) { perror("malloc"); exit(2); }
buf_fs = malloc(st_fs.st_size);
if (!buf_fs) { perror("malloc"); exit(2); }
if (st_kernel.st_size != read(fd_kernel,buf_kernel,st_kernel.st_size))
{ perror(argv[1]); exit(2); }
if (st_fs.st_size != read(fd_fs,buf_fs,st_fs.st_size))
{ perror(argv[2]); exit(2); }
for(l=0,p=buf_kernel; l < st_kernel.st_size - st_fs.st_size ; l++,p++ )
if(*p == 'M' && !strcmp(p,"MFS Filesystem goes here"))
goto found;
fprintf(stderr,"MFS filesystem signature not found in %s\n",argv[1]);
exit(1);
found:
if (!force)
for(l=0,q= p + SBOFF; l < st_fs.st_size - SBOFF ; l++,q++ )
if (*q)
goto fail;
memcpy(p+SBOFF,buf_fs+SBOFF,st_fs.st_size-SBOFF);
lseek(fd_kernel,0L,SEEK_SET);
if (st_kernel.st_size != write(fd_kernel,buf_kernel,st_kernel.st_size))
{ perror(argv[1]); exit(2); }
exit(0);
fail:
l += SBOFF;
fprintf(stderr,"Obstruction in kernel after %ld bytes (%ld Kbyte)\n",
l, l/1024);
fprintf(stderr,"Filesystem is %ld bytes (%ld Kbyte)\n",
(u_long)st_fs.st_size, (u_long)st_fs.st_size/1024);
exit(1);
}
/*
* I added a '-f' option to force writing the image into the kernel, even when
* there is already data (i.e. not zero) in the written area. This is useful
* to rewrite a changed MFS-image. Beware: If the written image is larger than
* the space reserved in the kernel (with option MFS_ROOT) then
* THIS WILL CORRUPT THE KERNEL!
*
*/
|
