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1da177e4 LT |
1 | /* |
2 | * linux/fs/readdir.c | |
3 | * | |
4 | * Copyright (C) 1995 Linus Torvalds | |
5 | */ | |
6 | ||
7 | #include <linux/module.h> | |
8 | #include <linux/time.h> | |
9 | #include <linux/mm.h> | |
10 | #include <linux/errno.h> | |
11 | #include <linux/stat.h> | |
12 | #include <linux/file.h> | |
13 | #include <linux/smp_lock.h> | |
14 | #include <linux/fs.h> | |
15 | #include <linux/dirent.h> | |
16 | #include <linux/security.h> | |
17 | #include <linux/syscalls.h> | |
18 | #include <linux/unistd.h> | |
19 | ||
20 | #include <asm/uaccess.h> | |
21 | ||
22 | int vfs_readdir(struct file *file, filldir_t filler, void *buf) | |
23 | { | |
24 | struct inode *inode = file->f_dentry->d_inode; | |
25 | int res = -ENOTDIR; | |
26 | if (!file->f_op || !file->f_op->readdir) | |
27 | goto out; | |
28 | ||
29 | res = security_file_permission(file, MAY_READ); | |
30 | if (res) | |
31 | goto out; | |
32 | ||
1b1dcc1b | 33 | mutex_lock(&inode->i_mutex); |
1da177e4 LT |
34 | res = -ENOENT; |
35 | if (!IS_DEADDIR(inode)) { | |
36 | res = file->f_op->readdir(file, buf, filler); | |
37 | file_accessed(file); | |
38 | } | |
1b1dcc1b | 39 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
40 | out: |
41 | return res; | |
42 | } | |
43 | ||
44 | EXPORT_SYMBOL(vfs_readdir); | |
45 | ||
46 | /* | |
47 | * Traditional linux readdir() handling.. | |
48 | * | |
49 | * "count=1" is a special case, meaning that the buffer is one | |
50 | * dirent-structure in size and that the code can't handle more | |
51 | * anyway. Thus the special "fillonedir()" function for that | |
52 | * case (the low-level handlers don't need to care about this). | |
53 | */ | |
54 | #define NAME_OFFSET(de) ((int) ((de)->d_name - (char __user *) (de))) | |
55 | #define ROUND_UP(x) (((x)+sizeof(long)-1) & ~(sizeof(long)-1)) | |
56 | ||
57 | #ifdef __ARCH_WANT_OLD_READDIR | |
58 | ||
59 | struct old_linux_dirent { | |
60 | unsigned long d_ino; | |
61 | unsigned long d_offset; | |
62 | unsigned short d_namlen; | |
63 | char d_name[1]; | |
64 | }; | |
65 | ||
66 | struct readdir_callback { | |
67 | struct old_linux_dirent __user * dirent; | |
68 | int result; | |
69 | }; | |
70 | ||
71 | static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset, | |
afefdbb2 | 72 | u64 ino, unsigned int d_type) |
1da177e4 LT |
73 | { |
74 | struct readdir_callback * buf = (struct readdir_callback *) __buf; | |
75 | struct old_linux_dirent __user * dirent; | |
afefdbb2 | 76 | unsigned long d_ino; |
1da177e4 LT |
77 | |
78 | if (buf->result) | |
79 | return -EINVAL; | |
afefdbb2 DH |
80 | d_ino = ino; |
81 | if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) | |
82 | return -EOVERFLOW; | |
1da177e4 LT |
83 | buf->result++; |
84 | dirent = buf->dirent; | |
85 | if (!access_ok(VERIFY_WRITE, dirent, | |
86 | (unsigned long)(dirent->d_name + namlen + 1) - | |
87 | (unsigned long)dirent)) | |
88 | goto efault; | |
afefdbb2 | 89 | if ( __put_user(d_ino, &dirent->d_ino) || |
1da177e4 LT |
90 | __put_user(offset, &dirent->d_offset) || |
91 | __put_user(namlen, &dirent->d_namlen) || | |
92 | __copy_to_user(dirent->d_name, name, namlen) || | |
93 | __put_user(0, dirent->d_name + namlen)) | |
94 | goto efault; | |
95 | return 0; | |
96 | efault: | |
97 | buf->result = -EFAULT; | |
98 | return -EFAULT; | |
99 | } | |
100 | ||
101 | asmlinkage long old_readdir(unsigned int fd, struct old_linux_dirent __user * dirent, unsigned int count) | |
102 | { | |
103 | int error; | |
104 | struct file * file; | |
105 | struct readdir_callback buf; | |
106 | ||
107 | error = -EBADF; | |
108 | file = fget(fd); | |
109 | if (!file) | |
110 | goto out; | |
111 | ||
112 | buf.result = 0; | |
113 | buf.dirent = dirent; | |
114 | ||
115 | error = vfs_readdir(file, fillonedir, &buf); | |
116 | if (error >= 0) | |
117 | error = buf.result; | |
118 | ||
119 | fput(file); | |
120 | out: | |
121 | return error; | |
122 | } | |
123 | ||
124 | #endif /* __ARCH_WANT_OLD_READDIR */ | |
125 | ||
126 | /* | |
127 | * New, all-improved, singing, dancing, iBCS2-compliant getdents() | |
128 | * interface. | |
129 | */ | |
130 | struct linux_dirent { | |
131 | unsigned long d_ino; | |
132 | unsigned long d_off; | |
133 | unsigned short d_reclen; | |
134 | char d_name[1]; | |
135 | }; | |
136 | ||
137 | struct getdents_callback { | |
138 | struct linux_dirent __user * current_dir; | |
139 | struct linux_dirent __user * previous; | |
140 | int count; | |
141 | int error; | |
142 | }; | |
143 | ||
144 | static int filldir(void * __buf, const char * name, int namlen, loff_t offset, | |
afefdbb2 | 145 | u64 ino, unsigned int d_type) |
1da177e4 LT |
146 | { |
147 | struct linux_dirent __user * dirent; | |
148 | struct getdents_callback * buf = (struct getdents_callback *) __buf; | |
afefdbb2 | 149 | unsigned long d_ino; |
1da177e4 LT |
150 | int reclen = ROUND_UP(NAME_OFFSET(dirent) + namlen + 2); |
151 | ||
152 | buf->error = -EINVAL; /* only used if we fail.. */ | |
153 | if (reclen > buf->count) | |
154 | return -EINVAL; | |
afefdbb2 DH |
155 | d_ino = ino; |
156 | if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) | |
157 | return -EOVERFLOW; | |
1da177e4 LT |
158 | dirent = buf->previous; |
159 | if (dirent) { | |
160 | if (__put_user(offset, &dirent->d_off)) | |
161 | goto efault; | |
162 | } | |
163 | dirent = buf->current_dir; | |
afefdbb2 | 164 | if (__put_user(d_ino, &dirent->d_ino)) |
1da177e4 LT |
165 | goto efault; |
166 | if (__put_user(reclen, &dirent->d_reclen)) | |
167 | goto efault; | |
168 | if (copy_to_user(dirent->d_name, name, namlen)) | |
169 | goto efault; | |
170 | if (__put_user(0, dirent->d_name + namlen)) | |
171 | goto efault; | |
172 | if (__put_user(d_type, (char __user *) dirent + reclen - 1)) | |
173 | goto efault; | |
174 | buf->previous = dirent; | |
175 | dirent = (void __user *)dirent + reclen; | |
176 | buf->current_dir = dirent; | |
177 | buf->count -= reclen; | |
178 | return 0; | |
179 | efault: | |
180 | buf->error = -EFAULT; | |
181 | return -EFAULT; | |
182 | } | |
183 | ||
184 | asmlinkage long sys_getdents(unsigned int fd, struct linux_dirent __user * dirent, unsigned int count) | |
185 | { | |
186 | struct file * file; | |
187 | struct linux_dirent __user * lastdirent; | |
188 | struct getdents_callback buf; | |
189 | int error; | |
190 | ||
191 | error = -EFAULT; | |
192 | if (!access_ok(VERIFY_WRITE, dirent, count)) | |
193 | goto out; | |
194 | ||
195 | error = -EBADF; | |
196 | file = fget(fd); | |
197 | if (!file) | |
198 | goto out; | |
199 | ||
200 | buf.current_dir = dirent; | |
201 | buf.previous = NULL; | |
202 | buf.count = count; | |
203 | buf.error = 0; | |
204 | ||
205 | error = vfs_readdir(file, filldir, &buf); | |
206 | if (error < 0) | |
207 | goto out_putf; | |
208 | error = buf.error; | |
209 | lastdirent = buf.previous; | |
210 | if (lastdirent) { | |
211 | if (put_user(file->f_pos, &lastdirent->d_off)) | |
212 | error = -EFAULT; | |
213 | else | |
214 | error = count - buf.count; | |
215 | } | |
216 | ||
217 | out_putf: | |
218 | fput(file); | |
219 | out: | |
220 | return error; | |
221 | } | |
222 | ||
223 | #define ROUND_UP64(x) (((x)+sizeof(u64)-1) & ~(sizeof(u64)-1)) | |
224 | ||
225 | struct getdents_callback64 { | |
226 | struct linux_dirent64 __user * current_dir; | |
227 | struct linux_dirent64 __user * previous; | |
228 | int count; | |
229 | int error; | |
230 | }; | |
231 | ||
232 | static int filldir64(void * __buf, const char * name, int namlen, loff_t offset, | |
afefdbb2 | 233 | u64 ino, unsigned int d_type) |
1da177e4 LT |
234 | { |
235 | struct linux_dirent64 __user *dirent; | |
236 | struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf; | |
237 | int reclen = ROUND_UP64(NAME_OFFSET(dirent) + namlen + 1); | |
238 | ||
239 | buf->error = -EINVAL; /* only used if we fail.. */ | |
240 | if (reclen > buf->count) | |
241 | return -EINVAL; | |
242 | dirent = buf->previous; | |
243 | if (dirent) { | |
244 | if (__put_user(offset, &dirent->d_off)) | |
245 | goto efault; | |
246 | } | |
247 | dirent = buf->current_dir; | |
248 | if (__put_user(ino, &dirent->d_ino)) | |
249 | goto efault; | |
250 | if (__put_user(0, &dirent->d_off)) | |
251 | goto efault; | |
252 | if (__put_user(reclen, &dirent->d_reclen)) | |
253 | goto efault; | |
254 | if (__put_user(d_type, &dirent->d_type)) | |
255 | goto efault; | |
256 | if (copy_to_user(dirent->d_name, name, namlen)) | |
257 | goto efault; | |
258 | if (__put_user(0, dirent->d_name + namlen)) | |
259 | goto efault; | |
260 | buf->previous = dirent; | |
261 | dirent = (void __user *)dirent + reclen; | |
262 | buf->current_dir = dirent; | |
263 | buf->count -= reclen; | |
264 | return 0; | |
265 | efault: | |
266 | buf->error = -EFAULT; | |
267 | return -EFAULT; | |
268 | } | |
269 | ||
270 | asmlinkage long sys_getdents64(unsigned int fd, struct linux_dirent64 __user * dirent, unsigned int count) | |
271 | { | |
272 | struct file * file; | |
273 | struct linux_dirent64 __user * lastdirent; | |
274 | struct getdents_callback64 buf; | |
275 | int error; | |
276 | ||
277 | error = -EFAULT; | |
278 | if (!access_ok(VERIFY_WRITE, dirent, count)) | |
279 | goto out; | |
280 | ||
281 | error = -EBADF; | |
282 | file = fget(fd); | |
283 | if (!file) | |
284 | goto out; | |
285 | ||
286 | buf.current_dir = dirent; | |
287 | buf.previous = NULL; | |
288 | buf.count = count; | |
289 | buf.error = 0; | |
290 | ||
291 | error = vfs_readdir(file, filldir64, &buf); | |
292 | if (error < 0) | |
293 | goto out_putf; | |
294 | error = buf.error; | |
295 | lastdirent = buf.previous; | |
296 | if (lastdirent) { | |
297 | typeof(lastdirent->d_off) d_off = file->f_pos; | |
298 | error = -EFAULT; | |
299 | if (__put_user(d_off, &lastdirent->d_off)) | |
300 | goto out_putf; | |
301 | error = count - buf.count; | |
302 | } | |
303 | ||
304 | out_putf: | |
305 | fput(file); | |
306 | out: | |
307 | return error; | |
308 | } |