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
33 down(&inode->i_sem);
34 res = -ENOENT;
35 if (!IS_DEADDIR(inode)) {
36 res = file->f_op->readdir(file, buf, filler);
37 file_accessed(file);
38 }
39 up(&inode->i_sem);
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,
72 ino_t ino, unsigned int d_type)
73 {
74 struct readdir_callback * buf = (struct readdir_callback *) __buf;
75 struct old_linux_dirent __user * dirent;
76
77 if (buf->result)
78 return -EINVAL;
79 buf->result++;
80 dirent = buf->dirent;
81 if (!access_ok(VERIFY_WRITE, dirent,
82 (unsigned long)(dirent->d_name + namlen + 1) -
83 (unsigned long)dirent))
84 goto efault;
85 if ( __put_user(ino, &dirent->d_ino) ||
86 __put_user(offset, &dirent->d_offset) ||
87 __put_user(namlen, &dirent->d_namlen) ||
88 __copy_to_user(dirent->d_name, name, namlen) ||
89 __put_user(0, dirent->d_name + namlen))
90 goto efault;
91 return 0;
92 efault:
93 buf->result = -EFAULT;
94 return -EFAULT;
95 }
96
97 asmlinkage long old_readdir(unsigned int fd, struct old_linux_dirent __user * dirent, unsigned int count)
98 {
99 int error;
100 struct file * file;
101 struct readdir_callback buf;
102
103 error = -EBADF;
104 file = fget(fd);
105 if (!file)
106 goto out;
107
108 buf.result = 0;
109 buf.dirent = dirent;
110
111 error = vfs_readdir(file, fillonedir, &buf);
112 if (error >= 0)
113 error = buf.result;
114
115 fput(file);
116 out:
117 return error;
118 }
119
120 #endif /* __ARCH_WANT_OLD_READDIR */
121
122 /*
123 * New, all-improved, singing, dancing, iBCS2-compliant getdents()
124 * interface.
125 */
126 struct linux_dirent {
127 unsigned long d_ino;
128 unsigned long d_off;
129 unsigned short d_reclen;
130 char d_name[1];
131 };
132
133 struct getdents_callback {
134 struct linux_dirent __user * current_dir;
135 struct linux_dirent __user * previous;
136 int count;
137 int error;
138 };
139
140 static int filldir(void * __buf, const char * name, int namlen, loff_t offset,
141 ino_t ino, unsigned int d_type)
142 {
143 struct linux_dirent __user * dirent;
144 struct getdents_callback * buf = (struct getdents_callback *) __buf;
145 int reclen = ROUND_UP(NAME_OFFSET(dirent) + namlen + 2);
146
147 buf->error = -EINVAL; /* only used if we fail.. */
148 if (reclen > buf->count)
149 return -EINVAL;
150 dirent = buf->previous;
151 if (dirent) {
152 if (__put_user(offset, &dirent->d_off))
153 goto efault;
154 }
155 dirent = buf->current_dir;
156 if (__put_user(ino, &dirent->d_ino))
157 goto efault;
158 if (__put_user(reclen, &dirent->d_reclen))
159 goto efault;
160 if (copy_to_user(dirent->d_name, name, namlen))
161 goto efault;
162 if (__put_user(0, dirent->d_name + namlen))
163 goto efault;
164 if (__put_user(d_type, (char __user *) dirent + reclen - 1))
165 goto efault;
166 buf->previous = dirent;
167 dirent = (void __user *)dirent + reclen;
168 buf->current_dir = dirent;
169 buf->count -= reclen;
170 return 0;
171 efault:
172 buf->error = -EFAULT;
173 return -EFAULT;
174 }
175
176 asmlinkage long sys_getdents(unsigned int fd, struct linux_dirent __user * dirent, unsigned int count)
177 {
178 struct file * file;
179 struct linux_dirent __user * lastdirent;
180 struct getdents_callback buf;
181 int error;
182
183 error = -EFAULT;
184 if (!access_ok(VERIFY_WRITE, dirent, count))
185 goto out;
186
187 error = -EBADF;
188 file = fget(fd);
189 if (!file)
190 goto out;
191
192 buf.current_dir = dirent;
193 buf.previous = NULL;
194 buf.count = count;
195 buf.error = 0;
196
197 error = vfs_readdir(file, filldir, &buf);
198 if (error < 0)
199 goto out_putf;
200 error = buf.error;
201 lastdirent = buf.previous;
202 if (lastdirent) {
203 if (put_user(file->f_pos, &lastdirent->d_off))
204 error = -EFAULT;
205 else
206 error = count - buf.count;
207 }
208
209 out_putf:
210 fput(file);
211 out:
212 return error;
213 }
214
215 #define ROUND_UP64(x) (((x)+sizeof(u64)-1) & ~(sizeof(u64)-1))
216
217 struct getdents_callback64 {
218 struct linux_dirent64 __user * current_dir;
219 struct linux_dirent64 __user * previous;
220 int count;
221 int error;
222 };
223
224 static int filldir64(void * __buf, const char * name, int namlen, loff_t offset,
225 ino_t ino, unsigned int d_type)
226 {
227 struct linux_dirent64 __user *dirent;
228 struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf;
229 int reclen = ROUND_UP64(NAME_OFFSET(dirent) + namlen + 1);
230
231 buf->error = -EINVAL; /* only used if we fail.. */
232 if (reclen > buf->count)
233 return -EINVAL;
234 dirent = buf->previous;
235 if (dirent) {
236 if (__put_user(offset, &dirent->d_off))
237 goto efault;
238 }
239 dirent = buf->current_dir;
240 if (__put_user(ino, &dirent->d_ino))
241 goto efault;
242 if (__put_user(0, &dirent->d_off))
243 goto efault;
244 if (__put_user(reclen, &dirent->d_reclen))
245 goto efault;
246 if (__put_user(d_type, &dirent->d_type))
247 goto efault;
248 if (copy_to_user(dirent->d_name, name, namlen))
249 goto efault;
250 if (__put_user(0, dirent->d_name + namlen))
251 goto efault;
252 buf->previous = dirent;
253 dirent = (void __user *)dirent + reclen;
254 buf->current_dir = dirent;
255 buf->count -= reclen;
256 return 0;
257 efault:
258 buf->error = -EFAULT;
259 return -EFAULT;
260 }
261
262 asmlinkage long sys_getdents64(unsigned int fd, struct linux_dirent64 __user * dirent, unsigned int count)
263 {
264 struct file * file;
265 struct linux_dirent64 __user * lastdirent;
266 struct getdents_callback64 buf;
267 int error;
268
269 error = -EFAULT;
270 if (!access_ok(VERIFY_WRITE, dirent, count))
271 goto out;
272
273 error = -EBADF;
274 file = fget(fd);
275 if (!file)
276 goto out;
277
278 buf.current_dir = dirent;
279 buf.previous = NULL;
280 buf.count = count;
281 buf.error = 0;
282
283 error = vfs_readdir(file, filldir64, &buf);
284 if (error < 0)
285 goto out_putf;
286 error = buf.error;
287 lastdirent = buf.previous;
288 if (lastdirent) {
289 typeof(lastdirent->d_off) d_off = file->f_pos;
290 error = -EFAULT;
291 if (__put_user(d_off, &lastdirent->d_off))
292 goto out_putf;
293 error = count - buf.count;
294 }
295
296 out_putf:
297 fput(file);
298 out:
299 return error;
300 }
301
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