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
|
/* Copyright 2021 Alain Knaff.
* This file is part of mtools.
*
* Mtools 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 3 of the License, or
* (at your option) any later version.
*
* Mtools 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 Mtools. If not, see <http://www.gnu.org/licenses/>.
*
* filter to support filesystems stored at an offset into their image
*/
#include "sysincludes.h"
#include "msdos.h"
#include "mtools.h"
#include "offset.h"
typedef struct Offset_t {
struct Stream_t head;
mt_off_t offset;
} Offset_t;
static ssize_t offset_pread(Stream_t *Stream, char *buf,
mt_off_t start, size_t len)
{
DeclareThis(Offset_t);
return PREADS(This->head.Next, buf, start+This->offset, len);
}
static ssize_t offset_pwrite(Stream_t *Stream, char *buf,
mt_off_t start, size_t len)
{
DeclareThis(Offset_t);
return PWRITES(This->head.Next, buf, start+This->offset, len);
}
static Class_t OffsetClass = {
0,
0,
offset_pread,
offset_pwrite,
0, /* flush */
0, /* free */
set_geom_pass_through, /* set_geom */
0, /* get_data */
0, /* pre-allocate */
get_dosConvert_pass_through, /* dos convert */
0, /* discard */
};
Stream_t *OpenOffset(Stream_t *Next, struct device *dev, off_t offset,
char *errmsg, mt_off_t *maxSize) {
Offset_t *This;
This = New(Offset_t);
if (!This){
printOom();
return 0;
}
memset((void*)This, 0, sizeof(Offset_t));
init_head(&This->head, &OffsetClass, Next);
This->offset = offset;
if(maxSize) {
if(This->offset > *maxSize) {
if(errmsg)
sprintf(errmsg,"init: Big disks not supported");
goto exit_0;
}
*maxSize -= This->offset;
}
if(adjust_tot_sectors(dev, This->offset, errmsg) < 0)
goto exit_0;
return &This->head;
exit_0:
Free(This);
return NULL;
}
|
