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1/*
2 * linux/fs/readdir.c
3 *
4 * Copyright (C) 1995 Linus Torvalds
5 */
6
7#include <linux/stddef.h>
8#include <linux/kernel.h>
9#include <linux/export.h>
10#include <linux/time.h>
11#include <linux/mm.h>
12#include <linux/errno.h>
13#include <linux/stat.h>
14#include <linux/file.h>
15#include <linux/fs.h>
16#include <linux/dirent.h>
17#include <linux/security.h>
18#include <linux/syscalls.h>
19#include <linux/unistd.h>
20
21#include <asm/uaccess.h>
22
23int iterate_dir(struct file *file, struct dir_context *ctx)
24{
25 struct inode *inode = file_inode(file);
26 int res = -ENOTDIR;
27 if (!file->f_op->iterate)
28 goto out;
29
30 res = security_file_permission(file, MAY_READ);
31 if (res)
32 goto out;
33
34 res = mutex_lock_killable(&inode->i_mutex);
35 if (res)
36 goto out;
37
38 res = -ENOENT;
39 if (!IS_DEADDIR(inode)) {
40 ctx->pos = file->f_pos;
41 res = file->f_op->iterate(file, ctx);
42 file->f_pos = ctx->pos;
43 file_accessed(file);
44 }
45 mutex_unlock(&inode->i_mutex);
46out:
47 return res;
48}
49EXPORT_SYMBOL(iterate_dir);
50
51/*
52 * Traditional linux readdir() handling..
53 *
54 * "count=1" is a special case, meaning that the buffer is one
55 * dirent-structure in size and that the code can't handle more
56 * anyway. Thus the special "fillonedir()" function for that
57 * case (the low-level handlers don't need to care about this).
58 */
59
60#ifdef __ARCH_WANT_OLD_READDIR
61
62struct old_linux_dirent {
63 unsigned long d_ino;
64 unsigned long d_offset;
65 unsigned short d_namlen;
66 char d_name[1];
67};
68
69struct readdir_callback {
70 struct dir_context ctx;
71 struct old_linux_dirent __user * dirent;
72 int result;
73};
74
75static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset,
76 u64 ino, unsigned int d_type)
77{
78 struct readdir_callback *buf = (struct readdir_callback *) __buf;
79 struct old_linux_dirent __user * dirent;
80 unsigned long d_ino;
81
82 if (buf->result)
83 return -EINVAL;
84 d_ino = ino;
85 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
86 buf->result = -EOVERFLOW;
87 return -EOVERFLOW;
88 }
89 buf->result++;
90 dirent = buf->dirent;
91 if (!access_ok(VERIFY_WRITE, dirent,
92 (unsigned long)(dirent->d_name + namlen + 1) -
93 (unsigned long)dirent))
94 goto efault;
95 if ( __put_user(d_ino, &dirent->d_ino) ||
96 __put_user(offset, &dirent->d_offset) ||
97 __put_user(namlen, &dirent->d_namlen) ||
98 __copy_to_user(dirent->d_name, name, namlen) ||
99 __put_user(0, dirent->d_name + namlen))
100 goto efault;
101 return 0;
102efault:
103 buf->result = -EFAULT;
104 return -EFAULT;
105}
106
107SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
108 struct old_linux_dirent __user *, dirent, unsigned int, count)
109{
110 int error;
111 struct fd f = fdget(fd);
112 struct readdir_callback buf = {
113 .ctx.actor = fillonedir,
114 .dirent = dirent
115 };
116
117 if (!f.file)
118 return -EBADF;
119
120 error = iterate_dir(f.file, &buf.ctx);
121 if (buf.result)
122 error = buf.result;
123
124 fdput(f);
125 return error;
126}
127
128#endif /* __ARCH_WANT_OLD_READDIR */
129
130/*
131 * New, all-improved, singing, dancing, iBCS2-compliant getdents()
132 * interface.
133 */
134struct linux_dirent {
135 unsigned long d_ino;
136 unsigned long d_off;
137 unsigned short d_reclen;
138 char d_name[1];
139};
140
141struct getdents_callback {
142 struct dir_context ctx;
143 struct linux_dirent __user * current_dir;
144 struct linux_dirent __user * previous;
145 int count;
146 int error;
147};
148
149static int filldir(void * __buf, const char * name, int namlen, loff_t offset,
150 u64 ino, unsigned int d_type)
151{
152 struct linux_dirent __user * dirent;
153 struct getdents_callback * buf = (struct getdents_callback *) __buf;
154 unsigned long d_ino;
155 int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
156 sizeof(long));
157
158 buf->error = -EINVAL; /* only used if we fail.. */
159 if (reclen > buf->count)
160 return -EINVAL;
161 d_ino = ino;
162 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
163 buf->error = -EOVERFLOW;
164 return -EOVERFLOW;
165 }
166 dirent = buf->previous;
167 if (dirent) {
168 if (__put_user(offset, &dirent->d_off))
169 goto efault;
170 }
171 dirent = buf->current_dir;
172 if (__put_user(d_ino, &dirent->d_ino))
173 goto efault;
174 if (__put_user(reclen, &dirent->d_reclen))
175 goto efault;
176 if (copy_to_user(dirent->d_name, name, namlen))
177 goto efault;
178 if (__put_user(0, dirent->d_name + namlen))
179 goto efault;
180 if (__put_user(d_type, (char __user *) dirent + reclen - 1))
181 goto efault;
182 buf->previous = dirent;
183 dirent = (void __user *)dirent + reclen;
184 buf->current_dir = dirent;
185 buf->count -= reclen;
186 return 0;
187efault:
188 buf->error = -EFAULT;
189 return -EFAULT;
190}
191
192SYSCALL_DEFINE3(getdents, unsigned int, fd,
193 struct linux_dirent __user *, dirent, unsigned int, count)
194{
195 struct fd f;
196 struct linux_dirent __user * lastdirent;
197 struct getdents_callback buf = {
198 .ctx.actor = filldir,
199 .count = count,
200 .current_dir = dirent
201 };
202 int error;
203
204 if (!access_ok(VERIFY_WRITE, dirent, count))
205 return -EFAULT;
206
207 f = fdget(fd);
208 if (!f.file)
209 return -EBADF;
210
211 error = iterate_dir(f.file, &buf.ctx);
212 if (error >= 0)
213 error = buf.error;
214 lastdirent = buf.previous;
215 if (lastdirent) {
216 if (put_user(buf.ctx.pos, &lastdirent->d_off))
217 error = -EFAULT;
218 else
219 error = count - buf.count;
220 }
221 fdput(f);
222 return error;
223}
224
225struct getdents_callback64 {
226 struct dir_context ctx;
227 struct linux_dirent64 __user * current_dir;
228 struct linux_dirent64 __user * previous;
229 int count;
230 int error;
231};
232
233static int filldir64(void * __buf, const char * name, int namlen, loff_t offset,
234 u64 ino, unsigned int d_type)
235{
236 struct linux_dirent64 __user *dirent;
237 struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf;
238 int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
239 sizeof(u64));
240
241 buf->error = -EINVAL; /* only used if we fail.. */
242 if (reclen > buf->count)
243 return -EINVAL;
244 dirent = buf->previous;
245 if (dirent) {
246 if (__put_user(offset, &dirent->d_off))
247 goto efault;
248 }
249 dirent = buf->current_dir;
250 if (__put_user(ino, &dirent->d_ino))
251 goto efault;
252 if (__put_user(0, &dirent->d_off))
253 goto efault;
254 if (__put_user(reclen, &dirent->d_reclen))
255 goto efault;
256 if (__put_user(d_type, &dirent->d_type))
257 goto efault;
258 if (copy_to_user(dirent->d_name, name, namlen))
259 goto efault;
260 if (__put_user(0, dirent->d_name + namlen))
261 goto efault;
262 buf->previous = dirent;
263 dirent = (void __user *)dirent + reclen;
264 buf->current_dir = dirent;
265 buf->count -= reclen;
266 return 0;
267efault:
268 buf->error = -EFAULT;
269 return -EFAULT;
270}
271
272SYSCALL_DEFINE3(getdents64, unsigned int, fd,
273 struct linux_dirent64 __user *, dirent, unsigned int, count)
274{
275 struct fd f;
276 struct linux_dirent64 __user * lastdirent;
277 struct getdents_callback64 buf = {
278 .ctx.actor = filldir64,
279 .count = count,
280 .current_dir = dirent
281 };
282 int error;
283
284 if (!access_ok(VERIFY_WRITE, dirent, count))
285 return -EFAULT;
286
287 f = fdget(fd);
288 if (!f.file)
289 return -EBADF;
290
291 error = iterate_dir(f.file, &buf.ctx);
292 if (error >= 0)
293 error = buf.error;
294 lastdirent = buf.previous;
295 if (lastdirent) {
296 typeof(lastdirent->d_off) d_off = buf.ctx.pos;
297 if (__put_user(d_off, &lastdirent->d_off))
298 error = -EFAULT;
299 else
300 error = count - buf.count;
301 }
302 fdput(f);
303 return error;
304}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/readdir.c
4 *
5 * Copyright (C) 1995 Linus Torvalds
6 */
7
8#include <linux/stddef.h>
9#include <linux/kernel.h>
10#include <linux/export.h>
11#include <linux/time.h>
12#include <linux/mm.h>
13#include <linux/errno.h>
14#include <linux/stat.h>
15#include <linux/file.h>
16#include <linux/fs.h>
17#include <linux/fsnotify.h>
18#include <linux/dirent.h>
19#include <linux/security.h>
20#include <linux/syscalls.h>
21#include <linux/unistd.h>
22#include <linux/compat.h>
23#include <linux/uaccess.h>
24
25#include <asm/unaligned.h>
26
27/*
28 * Note the "unsafe_put_user() semantics: we goto a
29 * label for errors.
30 */
31#define unsafe_copy_dirent_name(_dst, _src, _len, label) do { \
32 char __user *dst = (_dst); \
33 const char *src = (_src); \
34 size_t len = (_len); \
35 unsafe_put_user(0, dst+len, label); \
36 unsafe_copy_to_user(dst, src, len, label); \
37} while (0)
38
39
40int iterate_dir(struct file *file, struct dir_context *ctx)
41{
42 struct inode *inode = file_inode(file);
43 bool shared = false;
44 int res = -ENOTDIR;
45 if (file->f_op->iterate_shared)
46 shared = true;
47 else if (!file->f_op->iterate)
48 goto out;
49
50 res = security_file_permission(file, MAY_READ);
51 if (res)
52 goto out;
53
54 if (shared)
55 res = down_read_killable(&inode->i_rwsem);
56 else
57 res = down_write_killable(&inode->i_rwsem);
58 if (res)
59 goto out;
60
61 res = -ENOENT;
62 if (!IS_DEADDIR(inode)) {
63 ctx->pos = file->f_pos;
64 if (shared)
65 res = file->f_op->iterate_shared(file, ctx);
66 else
67 res = file->f_op->iterate(file, ctx);
68 file->f_pos = ctx->pos;
69 fsnotify_access(file);
70 file_accessed(file);
71 }
72 if (shared)
73 inode_unlock_shared(inode);
74 else
75 inode_unlock(inode);
76out:
77 return res;
78}
79EXPORT_SYMBOL(iterate_dir);
80
81/*
82 * POSIX says that a dirent name cannot contain NULL or a '/'.
83 *
84 * It's not 100% clear what we should really do in this case.
85 * The filesystem is clearly corrupted, but returning a hard
86 * error means that you now don't see any of the other names
87 * either, so that isn't a perfect alternative.
88 *
89 * And if you return an error, what error do you use? Several
90 * filesystems seem to have decided on EUCLEAN being the error
91 * code for EFSCORRUPTED, and that may be the error to use. Or
92 * just EIO, which is perhaps more obvious to users.
93 *
94 * In order to see the other file names in the directory, the
95 * caller might want to make this a "soft" error: skip the
96 * entry, and return the error at the end instead.
97 *
98 * Note that this should likely do a "memchr(name, 0, len)"
99 * check too, since that would be filesystem corruption as
100 * well. However, that case can't actually confuse user space,
101 * which has to do a strlen() on the name anyway to find the
102 * filename length, and the above "soft error" worry means
103 * that it's probably better left alone until we have that
104 * issue clarified.
105 *
106 * Note the PATH_MAX check - it's arbitrary but the real
107 * kernel limit on a possible path component, not NAME_MAX,
108 * which is the technical standard limit.
109 */
110static int verify_dirent_name(const char *name, int len)
111{
112 if (len <= 0 || len >= PATH_MAX)
113 return -EIO;
114 if (memchr(name, '/', len))
115 return -EIO;
116 return 0;
117}
118
119/*
120 * Traditional linux readdir() handling..
121 *
122 * "count=1" is a special case, meaning that the buffer is one
123 * dirent-structure in size and that the code can't handle more
124 * anyway. Thus the special "fillonedir()" function for that
125 * case (the low-level handlers don't need to care about this).
126 */
127
128#ifdef __ARCH_WANT_OLD_READDIR
129
130struct old_linux_dirent {
131 unsigned long d_ino;
132 unsigned long d_offset;
133 unsigned short d_namlen;
134 char d_name[1];
135};
136
137struct readdir_callback {
138 struct dir_context ctx;
139 struct old_linux_dirent __user * dirent;
140 int result;
141};
142
143static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
144 loff_t offset, u64 ino, unsigned int d_type)
145{
146 struct readdir_callback *buf =
147 container_of(ctx, struct readdir_callback, ctx);
148 struct old_linux_dirent __user * dirent;
149 unsigned long d_ino;
150
151 if (buf->result)
152 return -EINVAL;
153 d_ino = ino;
154 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
155 buf->result = -EOVERFLOW;
156 return -EOVERFLOW;
157 }
158 buf->result++;
159 dirent = buf->dirent;
160 if (!user_write_access_begin(dirent,
161 (unsigned long)(dirent->d_name + namlen + 1) -
162 (unsigned long)dirent))
163 goto efault;
164 unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
165 unsafe_put_user(offset, &dirent->d_offset, efault_end);
166 unsafe_put_user(namlen, &dirent->d_namlen, efault_end);
167 unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
168 user_write_access_end();
169 return 0;
170efault_end:
171 user_write_access_end();
172efault:
173 buf->result = -EFAULT;
174 return -EFAULT;
175}
176
177SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
178 struct old_linux_dirent __user *, dirent, unsigned int, count)
179{
180 int error;
181 struct fd f = fdget_pos(fd);
182 struct readdir_callback buf = {
183 .ctx.actor = fillonedir,
184 .dirent = dirent
185 };
186
187 if (!f.file)
188 return -EBADF;
189
190 error = iterate_dir(f.file, &buf.ctx);
191 if (buf.result)
192 error = buf.result;
193
194 fdput_pos(f);
195 return error;
196}
197
198#endif /* __ARCH_WANT_OLD_READDIR */
199
200/*
201 * New, all-improved, singing, dancing, iBCS2-compliant getdents()
202 * interface.
203 */
204struct linux_dirent {
205 unsigned long d_ino;
206 unsigned long d_off;
207 unsigned short d_reclen;
208 char d_name[1];
209};
210
211struct getdents_callback {
212 struct dir_context ctx;
213 struct linux_dirent __user * current_dir;
214 int prev_reclen;
215 int count;
216 int error;
217};
218
219static int filldir(struct dir_context *ctx, const char *name, int namlen,
220 loff_t offset, u64 ino, unsigned int d_type)
221{
222 struct linux_dirent __user *dirent, *prev;
223 struct getdents_callback *buf =
224 container_of(ctx, struct getdents_callback, ctx);
225 unsigned long d_ino;
226 int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
227 sizeof(long));
228 int prev_reclen;
229
230 buf->error = verify_dirent_name(name, namlen);
231 if (unlikely(buf->error))
232 return buf->error;
233 buf->error = -EINVAL; /* only used if we fail.. */
234 if (reclen > buf->count)
235 return -EINVAL;
236 d_ino = ino;
237 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
238 buf->error = -EOVERFLOW;
239 return -EOVERFLOW;
240 }
241 prev_reclen = buf->prev_reclen;
242 if (prev_reclen && signal_pending(current))
243 return -EINTR;
244 dirent = buf->current_dir;
245 prev = (void __user *) dirent - prev_reclen;
246 if (!user_write_access_begin(prev, reclen + prev_reclen))
247 goto efault;
248
249 /* This might be 'dirent->d_off', but if so it will get overwritten */
250 unsafe_put_user(offset, &prev->d_off, efault_end);
251 unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
252 unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
253 unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end);
254 unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
255 user_write_access_end();
256
257 buf->current_dir = (void __user *)dirent + reclen;
258 buf->prev_reclen = reclen;
259 buf->count -= reclen;
260 return 0;
261efault_end:
262 user_write_access_end();
263efault:
264 buf->error = -EFAULT;
265 return -EFAULT;
266}
267
268SYSCALL_DEFINE3(getdents, unsigned int, fd,
269 struct linux_dirent __user *, dirent, unsigned int, count)
270{
271 struct fd f;
272 struct getdents_callback buf = {
273 .ctx.actor = filldir,
274 .count = count,
275 .current_dir = dirent
276 };
277 int error;
278
279 f = fdget_pos(fd);
280 if (!f.file)
281 return -EBADF;
282
283 error = iterate_dir(f.file, &buf.ctx);
284 if (error >= 0)
285 error = buf.error;
286 if (buf.prev_reclen) {
287 struct linux_dirent __user * lastdirent;
288 lastdirent = (void __user *)buf.current_dir - buf.prev_reclen;
289
290 if (put_user(buf.ctx.pos, &lastdirent->d_off))
291 error = -EFAULT;
292 else
293 error = count - buf.count;
294 }
295 fdput_pos(f);
296 return error;
297}
298
299struct getdents_callback64 {
300 struct dir_context ctx;
301 struct linux_dirent64 __user * current_dir;
302 int prev_reclen;
303 int count;
304 int error;
305};
306
307static int filldir64(struct dir_context *ctx, const char *name, int namlen,
308 loff_t offset, u64 ino, unsigned int d_type)
309{
310 struct linux_dirent64 __user *dirent, *prev;
311 struct getdents_callback64 *buf =
312 container_of(ctx, struct getdents_callback64, ctx);
313 int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
314 sizeof(u64));
315 int prev_reclen;
316
317 buf->error = verify_dirent_name(name, namlen);
318 if (unlikely(buf->error))
319 return buf->error;
320 buf->error = -EINVAL; /* only used if we fail.. */
321 if (reclen > buf->count)
322 return -EINVAL;
323 prev_reclen = buf->prev_reclen;
324 if (prev_reclen && signal_pending(current))
325 return -EINTR;
326 dirent = buf->current_dir;
327 prev = (void __user *)dirent - prev_reclen;
328 if (!user_write_access_begin(prev, reclen + prev_reclen))
329 goto efault;
330
331 /* This might be 'dirent->d_off', but if so it will get overwritten */
332 unsafe_put_user(offset, &prev->d_off, efault_end);
333 unsafe_put_user(ino, &dirent->d_ino, efault_end);
334 unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
335 unsafe_put_user(d_type, &dirent->d_type, efault_end);
336 unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
337 user_write_access_end();
338
339 buf->prev_reclen = reclen;
340 buf->current_dir = (void __user *)dirent + reclen;
341 buf->count -= reclen;
342 return 0;
343
344efault_end:
345 user_write_access_end();
346efault:
347 buf->error = -EFAULT;
348 return -EFAULT;
349}
350
351SYSCALL_DEFINE3(getdents64, unsigned int, fd,
352 struct linux_dirent64 __user *, dirent, unsigned int, count)
353{
354 struct fd f;
355 struct getdents_callback64 buf = {
356 .ctx.actor = filldir64,
357 .count = count,
358 .current_dir = dirent
359 };
360 int error;
361
362 f = fdget_pos(fd);
363 if (!f.file)
364 return -EBADF;
365
366 error = iterate_dir(f.file, &buf.ctx);
367 if (error >= 0)
368 error = buf.error;
369 if (buf.prev_reclen) {
370 struct linux_dirent64 __user * lastdirent;
371 typeof(lastdirent->d_off) d_off = buf.ctx.pos;
372
373 lastdirent = (void __user *) buf.current_dir - buf.prev_reclen;
374 if (put_user(d_off, &lastdirent->d_off))
375 error = -EFAULT;
376 else
377 error = count - buf.count;
378 }
379 fdput_pos(f);
380 return error;
381}
382
383#ifdef CONFIG_COMPAT
384struct compat_old_linux_dirent {
385 compat_ulong_t d_ino;
386 compat_ulong_t d_offset;
387 unsigned short d_namlen;
388 char d_name[1];
389};
390
391struct compat_readdir_callback {
392 struct dir_context ctx;
393 struct compat_old_linux_dirent __user *dirent;
394 int result;
395};
396
397static int compat_fillonedir(struct dir_context *ctx, const char *name,
398 int namlen, loff_t offset, u64 ino,
399 unsigned int d_type)
400{
401 struct compat_readdir_callback *buf =
402 container_of(ctx, struct compat_readdir_callback, ctx);
403 struct compat_old_linux_dirent __user *dirent;
404 compat_ulong_t d_ino;
405
406 if (buf->result)
407 return -EINVAL;
408 d_ino = ino;
409 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
410 buf->result = -EOVERFLOW;
411 return -EOVERFLOW;
412 }
413 buf->result++;
414 dirent = buf->dirent;
415 if (!user_write_access_begin(dirent,
416 (unsigned long)(dirent->d_name + namlen + 1) -
417 (unsigned long)dirent))
418 goto efault;
419 unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
420 unsafe_put_user(offset, &dirent->d_offset, efault_end);
421 unsafe_put_user(namlen, &dirent->d_namlen, efault_end);
422 unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
423 user_write_access_end();
424 return 0;
425efault_end:
426 user_write_access_end();
427efault:
428 buf->result = -EFAULT;
429 return -EFAULT;
430}
431
432COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
433 struct compat_old_linux_dirent __user *, dirent, unsigned int, count)
434{
435 int error;
436 struct fd f = fdget_pos(fd);
437 struct compat_readdir_callback buf = {
438 .ctx.actor = compat_fillonedir,
439 .dirent = dirent
440 };
441
442 if (!f.file)
443 return -EBADF;
444
445 error = iterate_dir(f.file, &buf.ctx);
446 if (buf.result)
447 error = buf.result;
448
449 fdput_pos(f);
450 return error;
451}
452
453struct compat_linux_dirent {
454 compat_ulong_t d_ino;
455 compat_ulong_t d_off;
456 unsigned short d_reclen;
457 char d_name[1];
458};
459
460struct compat_getdents_callback {
461 struct dir_context ctx;
462 struct compat_linux_dirent __user *current_dir;
463 int prev_reclen;
464 int count;
465 int error;
466};
467
468static int compat_filldir(struct dir_context *ctx, const char *name, int namlen,
469 loff_t offset, u64 ino, unsigned int d_type)
470{
471 struct compat_linux_dirent __user *dirent, *prev;
472 struct compat_getdents_callback *buf =
473 container_of(ctx, struct compat_getdents_callback, ctx);
474 compat_ulong_t d_ino;
475 int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
476 namlen + 2, sizeof(compat_long_t));
477 int prev_reclen;
478
479 buf->error = verify_dirent_name(name, namlen);
480 if (unlikely(buf->error))
481 return buf->error;
482 buf->error = -EINVAL; /* only used if we fail.. */
483 if (reclen > buf->count)
484 return -EINVAL;
485 d_ino = ino;
486 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
487 buf->error = -EOVERFLOW;
488 return -EOVERFLOW;
489 }
490 prev_reclen = buf->prev_reclen;
491 if (prev_reclen && signal_pending(current))
492 return -EINTR;
493 dirent = buf->current_dir;
494 prev = (void __user *) dirent - prev_reclen;
495 if (!user_write_access_begin(prev, reclen + prev_reclen))
496 goto efault;
497
498 unsafe_put_user(offset, &prev->d_off, efault_end);
499 unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
500 unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
501 unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end);
502 unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
503 user_write_access_end();
504
505 buf->prev_reclen = reclen;
506 buf->current_dir = (void __user *)dirent + reclen;
507 buf->count -= reclen;
508 return 0;
509efault_end:
510 user_write_access_end();
511efault:
512 buf->error = -EFAULT;
513 return -EFAULT;
514}
515
516COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
517 struct compat_linux_dirent __user *, dirent, unsigned int, count)
518{
519 struct fd f;
520 struct compat_getdents_callback buf = {
521 .ctx.actor = compat_filldir,
522 .current_dir = dirent,
523 .count = count
524 };
525 int error;
526
527 f = fdget_pos(fd);
528 if (!f.file)
529 return -EBADF;
530
531 error = iterate_dir(f.file, &buf.ctx);
532 if (error >= 0)
533 error = buf.error;
534 if (buf.prev_reclen) {
535 struct compat_linux_dirent __user * lastdirent;
536 lastdirent = (void __user *)buf.current_dir - buf.prev_reclen;
537
538 if (put_user(buf.ctx.pos, &lastdirent->d_off))
539 error = -EFAULT;
540 else
541 error = count - buf.count;
542 }
543 fdput_pos(f);
544 return error;
545}
546#endif