libfuse: fuse-3.2.1/example/hello_ll.c Source File

libfuse

hello_ll.c
Go to the documentation of this file.
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
21 #define FUSE_USE_VERSION 31
22
23 #include <fuse_lowlevel.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <errno.h>
28 #include <fcntl.h>
29 #include <unistd.h>
30 #include <assert.h>
31
32 static const char *hello_str = "Hello World!\n";
33 static const char *hello_name = "hello";
34
35 static int hello_stat(fuse_ino_t ino, struct stat *stbuf)
36 {
37 stbuf->st_ino = ino;
38 switch (ino) {
39 case 1:
40 stbuf->st_mode = S_IFDIR | 0755;
41 stbuf->st_nlink = 2;
42 break;
43
44 case 2:
45 stbuf->st_mode = S_IFREG | 0444;
46 stbuf->st_nlink = 1;
47 stbuf->st_size = strlen(hello_str);
48 break;
49
50 default:
51 return -1;
52 }
53 return 0;
54 }
55
56 static void hello_ll_getattr(fuse_req_t req, fuse_ino_t ino,
57 struct fuse_file_info *fi)
58 {
59 struct stat stbuf;
60
61 (void) fi;
62
63 memset(&stbuf, 0, sizeof(stbuf));
64 if (hello_stat(ino, &stbuf) == -1)
65 fuse_reply_err(req, ENOENT);
66 else
67 fuse_reply_attr(req, &stbuf, 1.0);
68 }
69
70 static void hello_ll_lookup(fuse_req_t req, fuse_ino_t parent, const char *name)
71 {
72 struct fuse_entry_param e;
73
74 if (parent != 1 || strcmp(name, hello_name) != 0)
75 fuse_reply_err(req, ENOENT);
76 else {
77 memset(&e, 0, sizeof(e));
78 e.ino = 2;
79 e.attr_timeout = 1.0;
80 e.entry_timeout = 1.0;
81 hello_stat(e.ino, &e.attr);
82
83 fuse_reply_entry(req, &e);
84 }
85 }
86
87 struct dirbuf {
88 char *p;
89 size_t size;
90 };
91
92 static void dirbuf_add(fuse_req_t req, struct dirbuf *b, const char *name,
93 fuse_ino_t ino)
94 {
95 struct stat stbuf;
96 size_t oldsize = b->size;
97 b->size += fuse_add_direntry(req, NULL, 0, name, NULL, 0);
98 b->p = (char *) realloc(b->p, b->size);
99 memset(&stbuf, 0, sizeof(stbuf));
100 stbuf.st_ino = ino;
101 fuse_add_direntry(req, b->p + oldsize, b->size - oldsize, name, &stbuf,
102 b->size);
103 }
104
105 #define min(x, y) ((x) < (y) ? (x) : (y))
106
107 static int reply_buf_limited(fuse_req_t req, const char *buf, size_t bufsize,
108 off_t off, size_t maxsize)
109 {
110 if (off < bufsize)
111 return fuse_reply_buf(req, buf + off,
112 min(bufsize - off, maxsize));
113 else
114 return fuse_reply_buf(req, NULL, 0);
115 }
116
117 static void hello_ll_readdir(fuse_req_t req, fuse_ino_t ino, size_t size,
118 off_t off, struct fuse_file_info *fi)
119 {
120 (void) fi;
121
122 if (ino != 1)
123 fuse_reply_err(req, ENOTDIR);
124 else {
125 struct dirbuf b;
126
127 memset(&b, 0, sizeof(b));
128 dirbuf_add(req, &b, ".", 1);
129 dirbuf_add(req, &b, "..", 1);
130 dirbuf_add(req, &b, hello_name, 2);
131 reply_buf_limited(req, b.p, b.size, off, size);
132 free(b.p);
133 }
134 }
135
136 static void hello_ll_open(fuse_req_t req, fuse_ino_t ino,
137 struct fuse_file_info *fi)
138 {
139 if (ino != 2)
140 fuse_reply_err(req, EISDIR);
141 else if ((fi->flags & 3) != O_RDONLY)
142 fuse_reply_err(req, EACCES);
143 else
144 fuse_reply_open(req, fi);
145 }
146
147 static void hello_ll_read(fuse_req_t req, fuse_ino_t ino, size_t size,
148 off_t off, struct fuse_file_info *fi)
149 {
150 (void) fi;
151
152 assert(ino == 2);
153 reply_buf_limited(req, hello_str, strlen(hello_str), off, size);
154 }
155
156 static struct fuse_lowlevel_ops hello_ll_oper = {
157 .lookup = hello_ll_lookup,
158 .getattr = hello_ll_getattr,
159 .readdir = hello_ll_readdir,
160 .open = hello_ll_open,
161 .read = hello_ll_read,
162 };
163
164 int main(int argc, char *argv[])
165 {
166 struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
167 struct fuse_session *se;
168 struct fuse_cmdline_opts opts;
169 int ret = -1;
170
171 if (fuse_parse_cmdline(&args, &opts) != 0)
172 return 1;
173 if (opts.show_help) {
174 printf("usage: %s [options] <mountpoint>\n\n", argv[0]);
175 fuse_cmdline_help();
176 fuse_lowlevel_help();
177 ret = 0;
178 goto err_out1;
179 } else if (opts.show_version) {
180 printf("FUSE library version %s\n", fuse_pkgversion());
181 fuse_lowlevel_version();
182 ret = 0;
183 goto err_out1;
184 }
185
186 se = fuse_session_new(&args, &hello_ll_oper,
187 sizeof(hello_ll_oper), NULL);
188 if (se == NULL)
189 goto err_out1;
190
191 if (fuse_set_signal_handlers(se) != 0)
192 goto err_out2;
193
194 if (fuse_session_mount(se, opts.mountpoint) != 0)
195 goto err_out3;
196
197 fuse_daemonize(opts.foreground);
198
199 /* Block until ctrl+c or fusermount -u */
200 if (opts.singlethread)
201 ret = fuse_session_loop(se);
202 else
203 ret = fuse_session_loop_mt(se, opts.clone_fd);
204
205 fuse_session_unmount(se);
206 err_out3:
207 fuse_remove_signal_handlers(se);
208 err_out2:
209 fuse_session_destroy(se);
210 err_out1:
211 free(opts.mountpoint);
212 fuse_opt_free_args(&args);
213
214 return ret ? 1 : 0;
215 }
fuse_lowlevel_ops::lookup
void(* lookup)(fuse_req_t req, fuse_ino_t parent, const char *name)
Definition: fuse_lowlevel.h:218
fuse_remove_signal_handlers
void fuse_remove_signal_handlers(struct fuse_session *se)
Definition: fuse_signals.c:80
fuse_session_unmount
void fuse_session_unmount(struct fuse_session *se)
Definition: fuse_lowlevel.c:2916
fuse_reply_open
int fuse_reply_open(fuse_req_t req, const struct fuse_file_info *fi)
Definition: fuse_lowlevel.c:450
fuse_pkgversion
const char * fuse_pkgversion(void)
Definition: fuse.c:4923
FUSE_ARGS_INIT
#define FUSE_ARGS_INIT(argc, argv)
Definition: fuse_opt.h:123
fuse_reply_buf
int fuse_reply_buf(fuse_req_t req, const char *buf, size_t size)
Definition: fuse_lowlevel.c:469
fuse_entry_param
Definition: fuse_lowlevel.h:59
fuse_daemonize
int fuse_daemonize(int foreground)
Definition: helper.c:220
fuse_reply_entry
int fuse_reply_entry(fuse_req_t req, const struct fuse_entry_param *e)
Definition: fuse_lowlevel.c:398
fuse_session_loop
int fuse_session_loop(struct fuse_session *se)
Definition: fuse_loop.c:19
fuse_file_info
Definition: fuse_common.h:37
fuse_lowlevel_help
void fuse_lowlevel_help(void)
Definition: fuse_lowlevel.c:2587
fuse_file_info::flags
int flags
Definition: fuse_common.h:39
fuse_lowlevel_version
void fuse_lowlevel_version(void)
Definition: fuse_lowlevel.c:2580
fuse_reply_err
int fuse_reply_err(fuse_req_t req, int err)
Definition: fuse_lowlevel.c:311
fuse_req_t
struct fuse_req * fuse_req_t
Definition: fuse_lowlevel.h:49
fuse_reply_attr
int fuse_reply_attr(fuse_req_t req, const struct stat *attr, double attr_timeout)
Definition: fuse_lowlevel.c:430
fuse_parse_cmdline
int fuse_parse_cmdline(struct fuse_args *args, struct fuse_cmdline_opts *opts)
Definition: helper.c:197
fuse_session_new
struct fuse_session * fuse_session_new(struct fuse_args *args, const struct fuse_lowlevel_ops *op, size_t op_size, void *userdata)
Definition: fuse_lowlevel.c:2785
fuse_ino_t
uint64_t fuse_ino_t
Definition: fuse_lowlevel.h:46
fuse_add_direntry
size_t fuse_add_direntry(fuse_req_t req, char *buf, size_t bufsize, const char *name, const struct stat *stbuf, off_t off)
Definition: fuse_lowlevel.c:266
fuse_session_destroy
void fuse_session_destroy(struct fuse_session *se)
Definition: fuse_lowlevel.c:2597
fuse_lowlevel_ops
Definition: fuse_lowlevel.h:175
fuse_session_mount
int fuse_session_mount(struct fuse_session *se, const char *mountpoint)
Definition: fuse_lowlevel.c:2879
fuse_args
Definition: fuse_opt.h:109
fuse_set_signal_handlers
int fuse_set_signal_handlers(struct fuse_session *se)
Definition: fuse_signals.c:63
fuse_cmdline_help
void fuse_cmdline_help(void)
Definition: helper.c:128
fuse_opt_free_args
void fuse_opt_free_args(struct fuse_args *args)
Definition: fuse_opt.c:33