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
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
|
/*
FUSE: Filesystem in Userspace
Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
This program can be distributed under the terms of the GNU GPLv2.
See the file COPYING.
*/
/** @file
*
* This "filesystem" provides only a single file. The mountpoint
* needs to be a file rather than a directory. All writes to the
* file will be discarded, and reading the file always returns
* \0.
*
* Compile with:
*
* gcc -Wall null.c `pkg-config fuse3 --cflags --libs` -o null
*
* ## Source code ##
* \include passthrough_fh.c
*/
#define FUSE_USE_VERSION 31
#include <fuse.h>
#include <fuse_lowlevel.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>
static int null_getattr(const char *path, struct stat *stbuf,
struct fuse_file_info *fi)
{
(void) fi;
if(strcmp(path, "/") != 0)
return -ENOENT;
stbuf->st_mode = S_IFREG | 0644;
stbuf->st_nlink = 1;
stbuf->st_uid = getuid();
stbuf->st_gid = getgid();
stbuf->st_size = (1ULL << 32); /* 4G */
stbuf->st_blocks = 0;
stbuf->st_atime = stbuf->st_mtime = stbuf->st_ctime = time(NULL);
return 0;
}
static int null_truncate(const char *path, off_t size,
struct fuse_file_info *fi)
{
(void) size;
(void) fi;
if(strcmp(path, "/") != 0)
return -ENOENT;
return 0;
}
static int null_open(const char *path, struct fuse_file_info *fi)
{
(void) fi;
if(strcmp(path, "/") != 0)
return -ENOENT;
return 0;
}
static int null_read(const char *path, char *buf, size_t size,
off_t offset, struct fuse_file_info *fi)
{
(void) buf;
(void) offset;
(void) fi;
if(strcmp(path, "/") != 0)
return -ENOENT;
if (offset >= (1ULL << 32))
return 0;
memset(buf, 0, size);
return size;
}
static int null_write(const char *path, const char *buf, size_t size,
off_t offset, struct fuse_file_info *fi)
{
(void) buf;
(void) offset;
(void) fi;
if(strcmp(path, "/") != 0)
return -ENOENT;
return size;
}
static const struct fuse_operations null_oper = {
.getattr = null_getattr,
.truncate = null_truncate,
.open = null_open,
.read = null_read,
.write = null_write,
};
int main(int argc, char *argv[])
{
struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
struct fuse_cmdline_opts opts;
struct stat stbuf;
if (fuse_parse_cmdline(&args, &opts) != 0)
return 1;
fuse_opt_free_args(&args);
if (!opts.mountpoint) {
fprintf(stderr, "missing mountpoint parameter\n");
return 1;
}
if (stat(opts.mountpoint, &stbuf) == -1) {
fprintf(stderr ,"failed to access mountpoint %s: %s\n",
opts.mountpoint, strerror(errno));
free(opts.mountpoint);
return 1;
}
free(opts.mountpoint);
if (!S_ISREG(stbuf.st_mode)) {
fprintf(stderr, "mountpoint is not a regular file\n");
return 1;
}
return fuse_main(argc, argv, &null_oper, NULL);
}
|
