libfuse: fuse-3.2.3/example/null.c Source File

libfuse

null.c
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1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
25 #define FUSE_USE_VERSION 31
26
27 #include <fuse.h>
28 #include <fuse_lowlevel.h>
29 #include <stdio.h>
30 #include <string.h>
31 #include <unistd.h>
32 #include <time.h>
33 #include <errno.h>
34
35 static int null_getattr(const char *path, struct stat *stbuf,
36 struct fuse_file_info *fi)
37 {
38 (void) fi;
39
40 if(strcmp(path, "/") != 0)
41 return -ENOENT;
42
43 stbuf->st_mode = S_IFREG | 0644;
44 stbuf->st_nlink = 1;
45 stbuf->st_uid = getuid();
46 stbuf->st_gid = getgid();
47 stbuf->st_size = (1ULL << 32); /* 4G */
48 stbuf->st_blocks = 0;
49 stbuf->st_atime = stbuf->st_mtime = stbuf->st_ctime = time(NULL);
50
51 return 0;
52 }
53
54 static int null_truncate(const char *path, off_t size,
55 struct fuse_file_info *fi)
56 {
57 (void) size;
58 (void) fi;
59
60 if(strcmp(path, "/") != 0)
61 return -ENOENT;
62
63 return 0;
64 }
65
66 static int null_open(const char *path, struct fuse_file_info *fi)
67 {
68 (void) fi;
69
70 if(strcmp(path, "/") != 0)
71 return -ENOENT;
72
73 return 0;
74 }
75
76 static int null_read(const char *path, char *buf, size_t size,
77 off_t offset, struct fuse_file_info *fi)
78 {
79 (void) buf;
80 (void) offset;
81 (void) fi;
82
83 if(strcmp(path, "/") != 0)
84 return -ENOENT;
85
86 if (offset >= (1ULL << 32))
87 return 0;
88
89 memset(buf, 0, size);
90 return size;
91 }
92
93 static int null_write(const char *path, const char *buf, size_t size,
94 off_t offset, struct fuse_file_info *fi)
95 {
96 (void) buf;
97 (void) offset;
98 (void) fi;
99
100 if(strcmp(path, "/") != 0)
101 return -ENOENT;
102
103 return size;
104 }
105
106 static struct fuse_operations null_oper = {
107 .getattr = null_getattr,
108 .truncate = null_truncate,
109 .open = null_open,
110 .read = null_read,
111 .write = null_write,
112 };
113
114 int main(int argc, char *argv[])
115 {
116 struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
117 struct fuse_cmdline_opts opts;
118 struct stat stbuf;
119
120 if (fuse_parse_cmdline(&args, &opts) != 0)
121 return 1;
122
123 if (!opts.mountpoint) {
124 fprintf(stderr, "missing mountpoint parameter\n");
125 return 1;
126 }
127
128 if (stat(opts.mountpoint, &stbuf) == -1) {
129 fprintf(stderr ,"failed to access mountpoint %s: %s\n",
130 opts.mountpoint, strerror(errno));
131 return 1;
132 }
133 if (!S_ISREG(stbuf.st_mode)) {
134 fprintf(stderr, "mountpoint is not a regular file\n");
135 return 1;
136 }
137
138 return fuse_main(argc, argv, &null_oper, NULL);
139 }
fuse_parse_cmdline
int fuse_parse_cmdline(struct fuse_args *args, struct fuse_cmdline_opts *opts)
Definition: helper.c:197
fuse_main
#define fuse_main(argc, argv, op, private_data)
Definition: fuse.h:829
fuse_file_info
Definition: fuse_common.h:37
fuse_operations
Definition: fuse.h:299
FUSE_ARGS_INIT
#define FUSE_ARGS_INIT(argc, argv)
Definition: fuse_opt.h:123
fuse_operations::getattr
int(* getattr)(const char *, struct stat *, struct fuse_file_info *fi)
Definition: fuse.h:311
fuse_args
Definition: fuse_opt.h:109