libfuse

ioctl.c
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1 /*
2 FUSE fioc: FUSE ioctl example
3 Copyright (C) 2008 SUSE Linux Products GmbH
4 Copyright (C) 2008 Tejun Heo <teheo@suse.de>
5
6 This program can be distributed under the terms of the GNU GPLv2.
7 See the file COPYING.
8 */
9
25 #define FUSE_USE_VERSION 35
26
27 #include <fuse.h>
28 #include <stdlib.h>
29 #include <stdio.h>
30 #include <string.h>
31 #include <unistd.h>
32 #include <time.h>
33 #include <errno.h>
34
35 #include "ioctl.h"
36
37 #define FIOC_NAME "fioc"
38
39 enum {
40 FIOC_NONE,
41 FIOC_ROOT,
42 FIOC_FILE,
43 };
44
45 static void *fioc_buf;
46 static size_t fioc_size;
47
48 static int fioc_resize(size_t new_size)
49 {
50 void *new_buf;
51
52 if (new_size == fioc_size)
53 return 0;
54
55 new_buf = realloc(fioc_buf, new_size);
56 if (!new_buf && new_size)
57 return -ENOMEM;
58
59 if (new_size > fioc_size)
60 memset(new_buf + fioc_size, 0, new_size - fioc_size);
61
62 fioc_buf = new_buf;
63 fioc_size = new_size;
64
65 return 0;
66 }
67
68 static int fioc_expand(size_t new_size)
69 {
70 if (new_size > fioc_size)
71 return fioc_resize(new_size);
72 return 0;
73 }
74
75 static int fioc_file_type(const char *path)
76 {
77 if (strcmp(path, "/") == 0)
78 return FIOC_ROOT;
79 if (strcmp(path, "/" FIOC_NAME) == 0)
80 return FIOC_FILE;
81 return FIOC_NONE;
82 }
83
84 static int fioc_getattr(const char *path, struct stat *stbuf,
85 struct fuse_file_info *fi)
86 {
87 (void) fi;
88 stbuf->st_uid = getuid();
89 stbuf->st_gid = getgid();
90 stbuf->st_atime = stbuf->st_mtime = time(NULL);
91
92 switch (fioc_file_type(path)) {
93 case FIOC_ROOT:
94 stbuf->st_mode = S_IFDIR | 0755;
95 stbuf->st_nlink = 2;
96 break;
97 case FIOC_FILE:
98 stbuf->st_mode = S_IFREG | 0644;
99 stbuf->st_nlink = 1;
100 stbuf->st_size = fioc_size;
101 break;
102 case FIOC_NONE:
103 return -ENOENT;
104 }
105
106 return 0;
107 }
108
109 static int fioc_open(const char *path, struct fuse_file_info *fi)
110 {
111 (void) fi;
112
113 if (fioc_file_type(path) != FIOC_NONE)
114 return 0;
115 return -ENOENT;
116 }
117
118 static int fioc_do_read(char *buf, size_t size, off_t offset)
119 {
120 if (offset >= fioc_size)
121 return 0;
122
123 if (size > fioc_size - offset)
124 size = fioc_size - offset;
125
126 memcpy(buf, fioc_buf + offset, size);
127
128 return size;
129 }
130
131 static int fioc_read(const char *path, char *buf, size_t size,
132 off_t offset, struct fuse_file_info *fi)
133 {
134 (void) fi;
135
136 if (fioc_file_type(path) != FIOC_FILE)
137 return -EINVAL;
138
139 return fioc_do_read(buf, size, offset);
140 }
141
142 static int fioc_do_write(const char *buf, size_t size, off_t offset)
143 {
144 if (fioc_expand(offset + size))
145 return -ENOMEM;
146
147 memcpy(fioc_buf + offset, buf, size);
148
149 return size;
150 }
151
152 static int fioc_write(const char *path, const char *buf, size_t size,
153 off_t offset, struct fuse_file_info *fi)
154 {
155 (void) fi;
156
157 if (fioc_file_type(path) != FIOC_FILE)
158 return -EINVAL;
159
160 return fioc_do_write(buf, size, offset);
161 }
162
163 static int fioc_truncate(const char *path, off_t size,
164 struct fuse_file_info *fi)
165 {
166 (void) fi;
167 if (fioc_file_type(path) != FIOC_FILE)
168 return -EINVAL;
169
170 return fioc_resize(size);
171 }
172
173 static int fioc_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
174 off_t offset, struct fuse_file_info *fi,
175 enum fuse_readdir_flags flags)
176 {
177 (void) fi;
178 (void) offset;
179 (void) flags;
180
181 if (fioc_file_type(path) != FIOC_ROOT)
182 return -ENOENT;
183
184 filler(buf, ".", NULL, 0, 0);
185 filler(buf, "..", NULL, 0, 0);
186 filler(buf, FIOC_NAME, NULL, 0, 0);
187
188 return 0;
189 }
190
191 static int fioc_ioctl(const char *path, unsigned int cmd, void *arg,
192 struct fuse_file_info *fi, unsigned int flags, void *data)
193 {
194 (void) arg;
195 (void) fi;
196 (void) flags;
197
198 if (fioc_file_type(path) != FIOC_FILE)
199 return -EINVAL;
200
201 if (flags & FUSE_IOCTL_COMPAT)
202 return -ENOSYS;
203
204 switch (cmd) {
205 case FIOC_GET_SIZE:
206 *(size_t *)data = fioc_size;
207 return 0;
208
209 case FIOC_SET_SIZE:
210 fioc_resize(*(size_t *)data);
211 return 0;
212 }
213
214 return -EINVAL;
215 }
216
217 static const struct fuse_operations fioc_oper = {
218 .getattr = fioc_getattr,
219 .readdir = fioc_readdir,
220 .truncate = fioc_truncate,
221 .open = fioc_open,
222 .read = fioc_read,
223 .write = fioc_write,
224 .ioctl = fioc_ioctl,
225 };
226
227 int main(int argc, char *argv[])
228 {
229 return fuse_main(argc, argv, &fioc_oper, NULL);
230 }
FUSE_IOCTL_COMPAT
#define FUSE_IOCTL_COMPAT
Definition: fuse_common.h:371
ioctl.h
fuse_file_info
Definition: fuse_common.h:44
fuse_operations
Definition: fuse.h:299
fuse_main
#define fuse_main(argc, argv, op, private_data)
Definition: fuse.h:869
fuse_readdir_flags
fuse_readdir_flags
Definition: fuse.h:42
fuse_operations::getattr
int(* getattr)(const char *, struct stat *, struct fuse_file_info *fi)
Definition: fuse.h:311
fuse_fill_dir_t
int(* fuse_fill_dir_t)(void *buf, const char *name, const struct stat *stbuf, off_t off, enum fuse_fill_dir_flags flags)
Definition: fuse.h:82