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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/*
26 * Some filesystems were never converted to '->iterate_shared()'
27 * and their directory iterators want the inode lock held for
28 * writing. This wrapper allows for converting from the shared
29 * semantics to the exclusive inode use.
30 */
31int wrap_directory_iterator(struct file *file,
32 struct dir_context *ctx,
33 int (*iter)(struct file *, struct dir_context *))
34{
35 struct inode *inode = file_inode(file);
36 int ret;
37
38 /*
39 * We'd love to have an 'inode_upgrade_trylock()' operation,
40 * see the comment in mmap_upgrade_trylock() in mm/memory.c.
41 *
42 * But considering this is for "filesystems that never got
43 * converted", it really doesn't matter.
44 *
45 * Also note that since we have to return with the lock held
46 * for reading, we can't use the "killable()" locking here,
47 * since we do need to get the lock even if we're dying.
48 *
49 * We could do the write part killably and then get the read
50 * lock unconditionally if it mattered, but see above on why
51 * this does the very simplistic conversion.
52 */
53 up_read(&inode->i_rwsem);
54 down_write(&inode->i_rwsem);
55
56 /*
57 * Since we dropped the inode lock, we should do the
58 * DEADDIR test again. See 'iterate_dir()' below.
59 *
60 * Note that we don't need to re-do the f_pos games,
61 * since the file must be locked wrt f_pos anyway.
62 */
63 ret = -ENOENT;
64 if (!IS_DEADDIR(inode))
65 ret = iter(file, ctx);
66
67 downgrade_write(&inode->i_rwsem);
68 return ret;
69}
70EXPORT_SYMBOL(wrap_directory_iterator);
71
72/*
73 * Note the "unsafe_put_user()" semantics: we goto a
74 * label for errors.
75 */
76#define unsafe_copy_dirent_name(_dst, _src, _len, label) do { \
77 char __user *dst = (_dst); \
78 const char *src = (_src); \
79 size_t len = (_len); \
80 unsafe_put_user(0, dst+len, label); \
81 unsafe_copy_to_user(dst, src, len, label); \
82} while (0)
83
84
85int iterate_dir(struct file *file, struct dir_context *ctx)
86{
87 struct inode *inode = file_inode(file);
88 int res = -ENOTDIR;
89
90 if (!file->f_op->iterate_shared)
91 goto out;
92
93 res = security_file_permission(file, MAY_READ);
94 if (res)
95 goto out;
96
97 res = fsnotify_file_perm(file, MAY_READ);
98 if (res)
99 goto out;
100
101 res = down_read_killable(&inode->i_rwsem);
102 if (res)
103 goto out;
104
105 res = -ENOENT;
106 if (!IS_DEADDIR(inode)) {
107 ctx->pos = file->f_pos;
108 res = file->f_op->iterate_shared(file, ctx);
109 file->f_pos = ctx->pos;
110 fsnotify_access(file);
111 file_accessed(file);
112 }
113 inode_unlock_shared(inode);
114out:
115 return res;
116}
117EXPORT_SYMBOL(iterate_dir);
118
119/*
120 * POSIX says that a dirent name cannot contain NULL or a '/'.
121 *
122 * It's not 100% clear what we should really do in this case.
123 * The filesystem is clearly corrupted, but returning a hard
124 * error means that you now don't see any of the other names
125 * either, so that isn't a perfect alternative.
126 *
127 * And if you return an error, what error do you use? Several
128 * filesystems seem to have decided on EUCLEAN being the error
129 * code for EFSCORRUPTED, and that may be the error to use. Or
130 * just EIO, which is perhaps more obvious to users.
131 *
132 * In order to see the other file names in the directory, the
133 * caller might want to make this a "soft" error: skip the
134 * entry, and return the error at the end instead.
135 *
136 * Note that this should likely do a "memchr(name, 0, len)"
137 * check too, since that would be filesystem corruption as
138 * well. However, that case can't actually confuse user space,
139 * which has to do a strlen() on the name anyway to find the
140 * filename length, and the above "soft error" worry means
141 * that it's probably better left alone until we have that
142 * issue clarified.
143 *
144 * Note the PATH_MAX check - it's arbitrary but the real
145 * kernel limit on a possible path component, not NAME_MAX,
146 * which is the technical standard limit.
147 */
148static int verify_dirent_name(const char *name, int len)
149{
150 if (len <= 0 || len >= PATH_MAX)
151 return -EIO;
152 if (memchr(name, '/', len))
153 return -EIO;
154 return 0;
155}
156
157/*
158 * Traditional linux readdir() handling..
159 *
160 * "count=1" is a special case, meaning that the buffer is one
161 * dirent-structure in size and that the code can't handle more
162 * anyway. Thus the special "fillonedir()" function for that
163 * case (the low-level handlers don't need to care about this).
164 */
165
166#ifdef __ARCH_WANT_OLD_READDIR
167
168struct old_linux_dirent {
169 unsigned long d_ino;
170 unsigned long d_offset;
171 unsigned short d_namlen;
172 char d_name[];
173};
174
175struct readdir_callback {
176 struct dir_context ctx;
177 struct old_linux_dirent __user * dirent;
178 int result;
179};
180
181static bool fillonedir(struct dir_context *ctx, const char *name, int namlen,
182 loff_t offset, u64 ino, unsigned int d_type)
183{
184 struct readdir_callback *buf =
185 container_of(ctx, struct readdir_callback, ctx);
186 struct old_linux_dirent __user * dirent;
187 unsigned long d_ino;
188
189 if (buf->result)
190 return false;
191 buf->result = verify_dirent_name(name, namlen);
192 if (buf->result)
193 return false;
194 d_ino = ino;
195 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
196 buf->result = -EOVERFLOW;
197 return false;
198 }
199 buf->result++;
200 dirent = buf->dirent;
201 if (!user_write_access_begin(dirent,
202 (unsigned long)(dirent->d_name + namlen + 1) -
203 (unsigned long)dirent))
204 goto efault;
205 unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
206 unsafe_put_user(offset, &dirent->d_offset, efault_end);
207 unsafe_put_user(namlen, &dirent->d_namlen, efault_end);
208 unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
209 user_write_access_end();
210 return true;
211efault_end:
212 user_write_access_end();
213efault:
214 buf->result = -EFAULT;
215 return false;
216}
217
218SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
219 struct old_linux_dirent __user *, dirent, unsigned int, count)
220{
221 int error;
222 CLASS(fd_pos, f)(fd);
223 struct readdir_callback buf = {
224 .ctx.actor = fillonedir,
225 .dirent = dirent
226 };
227
228 if (fd_empty(f))
229 return -EBADF;
230
231 error = iterate_dir(fd_file(f), &buf.ctx);
232 if (buf.result)
233 error = buf.result;
234
235 return error;
236}
237
238#endif /* __ARCH_WANT_OLD_READDIR */
239
240/*
241 * New, all-improved, singing, dancing, iBCS2-compliant getdents()
242 * interface.
243 */
244struct linux_dirent {
245 unsigned long d_ino;
246 unsigned long d_off;
247 unsigned short d_reclen;
248 char d_name[];
249};
250
251struct getdents_callback {
252 struct dir_context ctx;
253 struct linux_dirent __user * current_dir;
254 int prev_reclen;
255 int count;
256 int error;
257};
258
259static bool filldir(struct dir_context *ctx, const char *name, int namlen,
260 loff_t offset, u64 ino, unsigned int d_type)
261{
262 struct linux_dirent __user *dirent, *prev;
263 struct getdents_callback *buf =
264 container_of(ctx, struct getdents_callback, ctx);
265 unsigned long d_ino;
266 int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
267 sizeof(long));
268 int prev_reclen;
269
270 buf->error = verify_dirent_name(name, namlen);
271 if (unlikely(buf->error))
272 return false;
273 buf->error = -EINVAL; /* only used if we fail.. */
274 if (reclen > buf->count)
275 return false;
276 d_ino = ino;
277 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
278 buf->error = -EOVERFLOW;
279 return false;
280 }
281 prev_reclen = buf->prev_reclen;
282 if (prev_reclen && signal_pending(current))
283 return false;
284 dirent = buf->current_dir;
285 prev = (void __user *) dirent - prev_reclen;
286 if (!user_write_access_begin(prev, reclen + prev_reclen))
287 goto efault;
288
289 /* This might be 'dirent->d_off', but if so it will get overwritten */
290 unsafe_put_user(offset, &prev->d_off, efault_end);
291 unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
292 unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
293 unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end);
294 unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
295 user_write_access_end();
296
297 buf->current_dir = (void __user *)dirent + reclen;
298 buf->prev_reclen = reclen;
299 buf->count -= reclen;
300 return true;
301efault_end:
302 user_write_access_end();
303efault:
304 buf->error = -EFAULT;
305 return false;
306}
307
308SYSCALL_DEFINE3(getdents, unsigned int, fd,
309 struct linux_dirent __user *, dirent, unsigned int, count)
310{
311 CLASS(fd_pos, f)(fd);
312 struct getdents_callback buf = {
313 .ctx.actor = filldir,
314 .count = count,
315 .current_dir = dirent
316 };
317 int error;
318
319 if (fd_empty(f))
320 return -EBADF;
321
322 error = iterate_dir(fd_file(f), &buf.ctx);
323 if (error >= 0)
324 error = buf.error;
325 if (buf.prev_reclen) {
326 struct linux_dirent __user * lastdirent;
327 lastdirent = (void __user *)buf.current_dir - buf.prev_reclen;
328
329 if (put_user(buf.ctx.pos, &lastdirent->d_off))
330 error = -EFAULT;
331 else
332 error = count - buf.count;
333 }
334 return error;
335}
336
337struct getdents_callback64 {
338 struct dir_context ctx;
339 struct linux_dirent64 __user * current_dir;
340 int prev_reclen;
341 int count;
342 int error;
343};
344
345static bool filldir64(struct dir_context *ctx, const char *name, int namlen,
346 loff_t offset, u64 ino, unsigned int d_type)
347{
348 struct linux_dirent64 __user *dirent, *prev;
349 struct getdents_callback64 *buf =
350 container_of(ctx, struct getdents_callback64, ctx);
351 int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
352 sizeof(u64));
353 int prev_reclen;
354
355 buf->error = verify_dirent_name(name, namlen);
356 if (unlikely(buf->error))
357 return false;
358 buf->error = -EINVAL; /* only used if we fail.. */
359 if (reclen > buf->count)
360 return false;
361 prev_reclen = buf->prev_reclen;
362 if (prev_reclen && signal_pending(current))
363 return false;
364 dirent = buf->current_dir;
365 prev = (void __user *)dirent - prev_reclen;
366 if (!user_write_access_begin(prev, reclen + prev_reclen))
367 goto efault;
368
369 /* This might be 'dirent->d_off', but if so it will get overwritten */
370 unsafe_put_user(offset, &prev->d_off, efault_end);
371 unsafe_put_user(ino, &dirent->d_ino, efault_end);
372 unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
373 unsafe_put_user(d_type, &dirent->d_type, efault_end);
374 unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
375 user_write_access_end();
376
377 buf->prev_reclen = reclen;
378 buf->current_dir = (void __user *)dirent + reclen;
379 buf->count -= reclen;
380 return true;
381
382efault_end:
383 user_write_access_end();
384efault:
385 buf->error = -EFAULT;
386 return false;
387}
388
389SYSCALL_DEFINE3(getdents64, unsigned int, fd,
390 struct linux_dirent64 __user *, dirent, unsigned int, count)
391{
392 CLASS(fd_pos, f)(fd);
393 struct getdents_callback64 buf = {
394 .ctx.actor = filldir64,
395 .count = count,
396 .current_dir = dirent
397 };
398 int error;
399
400 if (fd_empty(f))
401 return -EBADF;
402
403 error = iterate_dir(fd_file(f), &buf.ctx);
404 if (error >= 0)
405 error = buf.error;
406 if (buf.prev_reclen) {
407 struct linux_dirent64 __user * lastdirent;
408 typeof(lastdirent->d_off) d_off = buf.ctx.pos;
409
410 lastdirent = (void __user *) buf.current_dir - buf.prev_reclen;
411 if (put_user(d_off, &lastdirent->d_off))
412 error = -EFAULT;
413 else
414 error = count - buf.count;
415 }
416 return error;
417}
418
419#ifdef CONFIG_COMPAT
420struct compat_old_linux_dirent {
421 compat_ulong_t d_ino;
422 compat_ulong_t d_offset;
423 unsigned short d_namlen;
424 char d_name[];
425};
426
427struct compat_readdir_callback {
428 struct dir_context ctx;
429 struct compat_old_linux_dirent __user *dirent;
430 int result;
431};
432
433static bool compat_fillonedir(struct dir_context *ctx, const char *name,
434 int namlen, loff_t offset, u64 ino,
435 unsigned int d_type)
436{
437 struct compat_readdir_callback *buf =
438 container_of(ctx, struct compat_readdir_callback, ctx);
439 struct compat_old_linux_dirent __user *dirent;
440 compat_ulong_t d_ino;
441
442 if (buf->result)
443 return false;
444 buf->result = verify_dirent_name(name, namlen);
445 if (buf->result)
446 return false;
447 d_ino = ino;
448 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
449 buf->result = -EOVERFLOW;
450 return false;
451 }
452 buf->result++;
453 dirent = buf->dirent;
454 if (!user_write_access_begin(dirent,
455 (unsigned long)(dirent->d_name + namlen + 1) -
456 (unsigned long)dirent))
457 goto efault;
458 unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
459 unsafe_put_user(offset, &dirent->d_offset, efault_end);
460 unsafe_put_user(namlen, &dirent->d_namlen, efault_end);
461 unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
462 user_write_access_end();
463 return true;
464efault_end:
465 user_write_access_end();
466efault:
467 buf->result = -EFAULT;
468 return false;
469}
470
471COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
472 struct compat_old_linux_dirent __user *, dirent, unsigned int, count)
473{
474 int error;
475 CLASS(fd_pos, f)(fd);
476 struct compat_readdir_callback buf = {
477 .ctx.actor = compat_fillonedir,
478 .dirent = dirent
479 };
480
481 if (fd_empty(f))
482 return -EBADF;
483
484 error = iterate_dir(fd_file(f), &buf.ctx);
485 if (buf.result)
486 error = buf.result;
487
488 return error;
489}
490
491struct compat_linux_dirent {
492 compat_ulong_t d_ino;
493 compat_ulong_t d_off;
494 unsigned short d_reclen;
495 char d_name[];
496};
497
498struct compat_getdents_callback {
499 struct dir_context ctx;
500 struct compat_linux_dirent __user *current_dir;
501 int prev_reclen;
502 int count;
503 int error;
504};
505
506static bool compat_filldir(struct dir_context *ctx, const char *name, int namlen,
507 loff_t offset, u64 ino, unsigned int d_type)
508{
509 struct compat_linux_dirent __user *dirent, *prev;
510 struct compat_getdents_callback *buf =
511 container_of(ctx, struct compat_getdents_callback, ctx);
512 compat_ulong_t d_ino;
513 int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
514 namlen + 2, sizeof(compat_long_t));
515 int prev_reclen;
516
517 buf->error = verify_dirent_name(name, namlen);
518 if (unlikely(buf->error))
519 return false;
520 buf->error = -EINVAL; /* only used if we fail.. */
521 if (reclen > buf->count)
522 return false;
523 d_ino = ino;
524 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
525 buf->error = -EOVERFLOW;
526 return false;
527 }
528 prev_reclen = buf->prev_reclen;
529 if (prev_reclen && signal_pending(current))
530 return false;
531 dirent = buf->current_dir;
532 prev = (void __user *) dirent - prev_reclen;
533 if (!user_write_access_begin(prev, reclen + prev_reclen))
534 goto efault;
535
536 unsafe_put_user(offset, &prev->d_off, efault_end);
537 unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
538 unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
539 unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end);
540 unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
541 user_write_access_end();
542
543 buf->prev_reclen = reclen;
544 buf->current_dir = (void __user *)dirent + reclen;
545 buf->count -= reclen;
546 return true;
547efault_end:
548 user_write_access_end();
549efault:
550 buf->error = -EFAULT;
551 return false;
552}
553
554COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
555 struct compat_linux_dirent __user *, dirent, unsigned int, count)
556{
557 CLASS(fd_pos, f)(fd);
558 struct compat_getdents_callback buf = {
559 .ctx.actor = compat_filldir,
560 .current_dir = dirent,
561 .count = count
562 };
563 int error;
564
565 if (fd_empty(f))
566 return -EBADF;
567
568 error = iterate_dir(fd_file(f), &buf.ctx);
569 if (error >= 0)
570 error = buf.error;
571 if (buf.prev_reclen) {
572 struct compat_linux_dirent __user * lastdirent;
573 lastdirent = (void __user *)buf.current_dir - buf.prev_reclen;
574
575 if (put_user(buf.ctx.pos, &lastdirent->d_off))
576 error = -EFAULT;
577 else
578 error = count - buf.count;
579 }
580 return error;
581}
582#endif
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/fsnotify.h>
17#include <linux/dirent.h>
18#include <linux/security.h>
19#include <linux/syscalls.h>
20#include <linux/unistd.h>
21
22#include <asm/uaccess.h>
23
24int iterate_dir(struct file *file, struct dir_context *ctx)
25{
26 struct inode *inode = file_inode(file);
27 int res = -ENOTDIR;
28 if (!file->f_op->iterate)
29 goto out;
30
31 res = security_file_permission(file, MAY_READ);
32 if (res)
33 goto out;
34
35 res = mutex_lock_killable(&inode->i_mutex);
36 if (res)
37 goto out;
38
39 res = -ENOENT;
40 if (!IS_DEADDIR(inode)) {
41 ctx->pos = file->f_pos;
42 res = file->f_op->iterate(file, ctx);
43 file->f_pos = ctx->pos;
44 fsnotify_access(file);
45 file_accessed(file);
46 }
47 inode_unlock(inode);
48out:
49 return res;
50}
51EXPORT_SYMBOL(iterate_dir);
52
53/*
54 * Traditional linux readdir() handling..
55 *
56 * "count=1" is a special case, meaning that the buffer is one
57 * dirent-structure in size and that the code can't handle more
58 * anyway. Thus the special "fillonedir()" function for that
59 * case (the low-level handlers don't need to care about this).
60 */
61
62#ifdef __ARCH_WANT_OLD_READDIR
63
64struct old_linux_dirent {
65 unsigned long d_ino;
66 unsigned long d_offset;
67 unsigned short d_namlen;
68 char d_name[1];
69};
70
71struct readdir_callback {
72 struct dir_context ctx;
73 struct old_linux_dirent __user * dirent;
74 int result;
75};
76
77static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
78 loff_t offset, u64 ino, unsigned int d_type)
79{
80 struct readdir_callback *buf =
81 container_of(ctx, struct readdir_callback, ctx);
82 struct old_linux_dirent __user * dirent;
83 unsigned long d_ino;
84
85 if (buf->result)
86 return -EINVAL;
87 d_ino = ino;
88 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
89 buf->result = -EOVERFLOW;
90 return -EOVERFLOW;
91 }
92 buf->result++;
93 dirent = buf->dirent;
94 if (!access_ok(VERIFY_WRITE, dirent,
95 (unsigned long)(dirent->d_name + namlen + 1) -
96 (unsigned long)dirent))
97 goto efault;
98 if ( __put_user(d_ino, &dirent->d_ino) ||
99 __put_user(offset, &dirent->d_offset) ||
100 __put_user(namlen, &dirent->d_namlen) ||
101 __copy_to_user(dirent->d_name, name, namlen) ||
102 __put_user(0, dirent->d_name + namlen))
103 goto efault;
104 return 0;
105efault:
106 buf->result = -EFAULT;
107 return -EFAULT;
108}
109
110SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
111 struct old_linux_dirent __user *, dirent, unsigned int, count)
112{
113 int error;
114 struct fd f = fdget(fd);
115 struct readdir_callback buf = {
116 .ctx.actor = fillonedir,
117 .dirent = dirent
118 };
119
120 if (!f.file)
121 return -EBADF;
122
123 error = iterate_dir(f.file, &buf.ctx);
124 if (buf.result)
125 error = buf.result;
126
127 fdput(f);
128 return error;
129}
130
131#endif /* __ARCH_WANT_OLD_READDIR */
132
133/*
134 * New, all-improved, singing, dancing, iBCS2-compliant getdents()
135 * interface.
136 */
137struct linux_dirent {
138 unsigned long d_ino;
139 unsigned long d_off;
140 unsigned short d_reclen;
141 char d_name[1];
142};
143
144struct getdents_callback {
145 struct dir_context ctx;
146 struct linux_dirent __user * current_dir;
147 struct linux_dirent __user * previous;
148 int count;
149 int error;
150};
151
152static int filldir(struct dir_context *ctx, const char *name, int namlen,
153 loff_t offset, u64 ino, unsigned int d_type)
154{
155 struct linux_dirent __user * dirent;
156 struct getdents_callback *buf =
157 container_of(ctx, struct getdents_callback, ctx);
158 unsigned long d_ino;
159 int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
160 sizeof(long));
161
162 buf->error = -EINVAL; /* only used if we fail.. */
163 if (reclen > buf->count)
164 return -EINVAL;
165 d_ino = ino;
166 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
167 buf->error = -EOVERFLOW;
168 return -EOVERFLOW;
169 }
170 dirent = buf->previous;
171 if (dirent) {
172 if (__put_user(offset, &dirent->d_off))
173 goto efault;
174 }
175 dirent = buf->current_dir;
176 if (__put_user(d_ino, &dirent->d_ino))
177 goto efault;
178 if (__put_user(reclen, &dirent->d_reclen))
179 goto efault;
180 if (copy_to_user(dirent->d_name, name, namlen))
181 goto efault;
182 if (__put_user(0, dirent->d_name + namlen))
183 goto efault;
184 if (__put_user(d_type, (char __user *) dirent + reclen - 1))
185 goto efault;
186 buf->previous = dirent;
187 dirent = (void __user *)dirent + reclen;
188 buf->current_dir = dirent;
189 buf->count -= reclen;
190 return 0;
191efault:
192 buf->error = -EFAULT;
193 return -EFAULT;
194}
195
196SYSCALL_DEFINE3(getdents, unsigned int, fd,
197 struct linux_dirent __user *, dirent, unsigned int, count)
198{
199 struct fd f;
200 struct linux_dirent __user * lastdirent;
201 struct getdents_callback buf = {
202 .ctx.actor = filldir,
203 .count = count,
204 .current_dir = dirent
205 };
206 int error;
207
208 if (!access_ok(VERIFY_WRITE, dirent, count))
209 return -EFAULT;
210
211 f = fdget(fd);
212 if (!f.file)
213 return -EBADF;
214
215 error = iterate_dir(f.file, &buf.ctx);
216 if (error >= 0)
217 error = buf.error;
218 lastdirent = buf.previous;
219 if (lastdirent) {
220 if (put_user(buf.ctx.pos, &lastdirent->d_off))
221 error = -EFAULT;
222 else
223 error = count - buf.count;
224 }
225 fdput(f);
226 return error;
227}
228
229struct getdents_callback64 {
230 struct dir_context ctx;
231 struct linux_dirent64 __user * current_dir;
232 struct linux_dirent64 __user * previous;
233 int count;
234 int error;
235};
236
237static int filldir64(struct dir_context *ctx, const char *name, int namlen,
238 loff_t offset, u64 ino, unsigned int d_type)
239{
240 struct linux_dirent64 __user *dirent;
241 struct getdents_callback64 *buf =
242 container_of(ctx, struct getdents_callback64, ctx);
243 int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
244 sizeof(u64));
245
246 buf->error = -EINVAL; /* only used if we fail.. */
247 if (reclen > buf->count)
248 return -EINVAL;
249 dirent = buf->previous;
250 if (dirent) {
251 if (__put_user(offset, &dirent->d_off))
252 goto efault;
253 }
254 dirent = buf->current_dir;
255 if (__put_user(ino, &dirent->d_ino))
256 goto efault;
257 if (__put_user(0, &dirent->d_off))
258 goto efault;
259 if (__put_user(reclen, &dirent->d_reclen))
260 goto efault;
261 if (__put_user(d_type, &dirent->d_type))
262 goto efault;
263 if (copy_to_user(dirent->d_name, name, namlen))
264 goto efault;
265 if (__put_user(0, dirent->d_name + namlen))
266 goto efault;
267 buf->previous = dirent;
268 dirent = (void __user *)dirent + reclen;
269 buf->current_dir = dirent;
270 buf->count -= reclen;
271 return 0;
272efault:
273 buf->error = -EFAULT;
274 return -EFAULT;
275}
276
277SYSCALL_DEFINE3(getdents64, unsigned int, fd,
278 struct linux_dirent64 __user *, dirent, unsigned int, count)
279{
280 struct fd f;
281 struct linux_dirent64 __user * lastdirent;
282 struct getdents_callback64 buf = {
283 .ctx.actor = filldir64,
284 .count = count,
285 .current_dir = dirent
286 };
287 int error;
288
289 if (!access_ok(VERIFY_WRITE, dirent, count))
290 return -EFAULT;
291
292 f = fdget(fd);
293 if (!f.file)
294 return -EBADF;
295
296 error = iterate_dir(f.file, &buf.ctx);
297 if (error >= 0)
298 error = buf.error;
299 lastdirent = buf.previous;
300 if (lastdirent) {
301 typeof(lastdirent->d_off) d_off = buf.ctx.pos;
302 if (__put_user(d_off, &lastdirent->d_off))
303 error = -EFAULT;
304 else
305 error = count - buf.count;
306 }
307 fdput(f);
308 return error;
309}