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10#include <linux/syscalls.h>
11#include <linux/export.h>
12#include <linux/fs.h>
13#include <linux/mm.h>
14#include <linux/sched/signal.h>
15#include <linux/slab.h>
16#include <linux/file.h>
17#include <linux/fdtable.h>
18#include <linux/bitops.h>
19#include <linux/spinlock.h>
20#include <linux/rcupdate.h>
21
22unsigned int sysctl_nr_open __read_mostly = 1024*1024;
23unsigned int sysctl_nr_open_min = BITS_PER_LONG;
24
25#define __const_min(x, y) ((x) < (y) ? (x) : (y))
26unsigned int sysctl_nr_open_max =
27 __const_min(INT_MAX, ~(size_t)0/sizeof(void *)) & -BITS_PER_LONG;
28
29static void __free_fdtable(struct fdtable *fdt)
30{
31 kvfree(fdt->fd);
32 kvfree(fdt->open_fds);
33 kfree(fdt);
34}
35
36static void free_fdtable_rcu(struct rcu_head *rcu)
37{
38 __free_fdtable(container_of(rcu, struct fdtable, rcu));
39}
40
41#define BITBIT_NR(nr) BITS_TO_LONGS(BITS_TO_LONGS(nr))
42#define BITBIT_SIZE(nr) (BITBIT_NR(nr) * sizeof(long))
43
44
45
46
47
48
49static void copy_fd_bitmaps(struct fdtable *nfdt, struct fdtable *ofdt,
50 unsigned int count)
51{
52 unsigned int cpy, set;
53
54 cpy = count / BITS_PER_BYTE;
55 set = (nfdt->max_fds - count) / BITS_PER_BYTE;
56 memcpy(nfdt->open_fds, ofdt->open_fds, cpy);
57 memset((char *)nfdt->open_fds + cpy, 0, set);
58 memcpy(nfdt->close_on_exec, ofdt->close_on_exec, cpy);
59 memset((char *)nfdt->close_on_exec + cpy, 0, set);
60
61 cpy = BITBIT_SIZE(count);
62 set = BITBIT_SIZE(nfdt->max_fds) - cpy;
63 memcpy(nfdt->full_fds_bits, ofdt->full_fds_bits, cpy);
64 memset((char *)nfdt->full_fds_bits + cpy, 0, set);
65}
66
67
68
69
70
71static void copy_fdtable(struct fdtable *nfdt, struct fdtable *ofdt)
72{
73 unsigned int cpy, set;
74
75 BUG_ON(nfdt->max_fds < ofdt->max_fds);
76
77 cpy = ofdt->max_fds * sizeof(struct file *);
78 set = (nfdt->max_fds - ofdt->max_fds) * sizeof(struct file *);
79 memcpy(nfdt->fd, ofdt->fd, cpy);
80 memset((char *)nfdt->fd + cpy, 0, set);
81
82 copy_fd_bitmaps(nfdt, ofdt, ofdt->max_fds);
83}
84
85static struct fdtable * alloc_fdtable(unsigned int nr)
86{
87 struct fdtable *fdt;
88 void *data;
89
90
91
92
93
94
95
96
97 nr /= (1024 / sizeof(struct file *));
98 nr = roundup_pow_of_two(nr + 1);
99 nr *= (1024 / sizeof(struct file *));
100
101
102
103
104
105
106
107
108 if (unlikely(nr > sysctl_nr_open))
109 nr = ((sysctl_nr_open - 1) | (BITS_PER_LONG - 1)) + 1;
110
111 fdt = kmalloc(sizeof(struct fdtable), GFP_KERNEL_ACCOUNT);
112 if (!fdt)
113 goto out;
114 fdt->max_fds = nr;
115 data = kvmalloc_array(nr, sizeof(struct file *), GFP_KERNEL_ACCOUNT);
116 if (!data)
117 goto out_fdt;
118 fdt->fd = data;
119
120 data = kvmalloc(max_t(size_t,
121 2 * nr / BITS_PER_BYTE + BITBIT_SIZE(nr), L1_CACHE_BYTES),
122 GFP_KERNEL_ACCOUNT);
123 if (!data)
124 goto out_arr;
125 fdt->open_fds = data;
126 data += nr / BITS_PER_BYTE;
127 fdt->close_on_exec = data;
128 data += nr / BITS_PER_BYTE;
129 fdt->full_fds_bits = data;
130
131 return fdt;
132
133out_arr:
134 kvfree(fdt->fd);
135out_fdt:
136 kfree(fdt);
137out:
138 return NULL;
139}
140
141
142
143
144
145
146
147
148static int expand_fdtable(struct files_struct *files, unsigned int nr)
149 __releases(files->file_lock)
150 __acquires(files->file_lock)
151{
152 struct fdtable *new_fdt, *cur_fdt;
153
154 spin_unlock(&files->file_lock);
155 new_fdt = alloc_fdtable(nr);
156
157
158
159
160 if (atomic_read(&files->count) > 1)
161 synchronize_sched();
162
163 spin_lock(&files->file_lock);
164 if (!new_fdt)
165 return -ENOMEM;
166
167
168
169
170 if (unlikely(new_fdt->max_fds <= nr)) {
171 __free_fdtable(new_fdt);
172 return -EMFILE;
173 }
174 cur_fdt = files_fdtable(files);
175 BUG_ON(nr < cur_fdt->max_fds);
176 copy_fdtable(new_fdt, cur_fdt);
177 rcu_assign_pointer(files->fdt, new_fdt);
178 if (cur_fdt != &files->fdtab)
179 call_rcu(&cur_fdt->rcu, free_fdtable_rcu);
180
181 smp_wmb();
182 return 1;
183}
184
185
186
187
188
189
190
191
192
193static int expand_files(struct files_struct *files, unsigned int nr)
194 __releases(files->file_lock)
195 __acquires(files->file_lock)
196{
197 struct fdtable *fdt;
198 int expanded = 0;
199
200repeat:
201 fdt = files_fdtable(files);
202
203
204 if (nr < fdt->max_fds)
205 return expanded;
206
207
208 if (nr >= sysctl_nr_open)
209 return -EMFILE;
210
211 if (unlikely(files->resize_in_progress)) {
212 spin_unlock(&files->file_lock);
213 expanded = 1;
214 wait_event(files->resize_wait, !files->resize_in_progress);
215 spin_lock(&files->file_lock);
216 goto repeat;
217 }
218
219
220 files->resize_in_progress = true;
221 expanded = expand_fdtable(files, nr);
222 files->resize_in_progress = false;
223
224 wake_up_all(&files->resize_wait);
225 return expanded;
226}
227
228static inline void __set_close_on_exec(unsigned int fd, struct fdtable *fdt)
229{
230 __set_bit(fd, fdt->close_on_exec);
231}
232
233static inline void __clear_close_on_exec(unsigned int fd, struct fdtable *fdt)
234{
235 if (test_bit(fd, fdt->close_on_exec))
236 __clear_bit(fd, fdt->close_on_exec);
237}
238
239static inline void __set_open_fd(unsigned int fd, struct fdtable *fdt)
240{
241 __set_bit(fd, fdt->open_fds);
242 fd /= BITS_PER_LONG;
243 if (!~fdt->open_fds[fd])
244 __set_bit(fd, fdt->full_fds_bits);
245}
246
247static inline void __clear_open_fd(unsigned int fd, struct fdtable *fdt)
248{
249 __clear_bit(fd, fdt->open_fds);
250 __clear_bit(fd / BITS_PER_LONG, fdt->full_fds_bits);
251}
252
253static unsigned int count_open_files(struct fdtable *fdt)
254{
255 unsigned int size = fdt->max_fds;
256 unsigned int i;
257
258
259 for (i = size / BITS_PER_LONG; i > 0; ) {
260 if (fdt->open_fds[--i])
261 break;
262 }
263 i = (i + 1) * BITS_PER_LONG;
264 return i;
265}
266
267
268
269
270
271
272struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
273{
274 struct files_struct *newf;
275 struct file **old_fds, **new_fds;
276 unsigned int open_files, i;
277 struct fdtable *old_fdt, *new_fdt;
278
279 *errorp = -ENOMEM;
280 newf = kmem_cache_alloc(files_cachep, GFP_KERNEL);
281 if (!newf)
282 goto out;
283
284 atomic_set(&newf->count, 1);
285
286 spin_lock_init(&newf->file_lock);
287 newf->resize_in_progress = false;
288 init_waitqueue_head(&newf->resize_wait);
289 newf->next_fd = 0;
290 new_fdt = &newf->fdtab;
291 new_fdt->max_fds = NR_OPEN_DEFAULT;
292 new_fdt->close_on_exec = newf->close_on_exec_init;
293 new_fdt->open_fds = newf->open_fds_init;
294 new_fdt->full_fds_bits = newf->full_fds_bits_init;
295 new_fdt->fd = &newf->fd_array[0];
296
297 spin_lock(&oldf->file_lock);
298 old_fdt = files_fdtable(oldf);
299 open_files = count_open_files(old_fdt);
300
301
302
303
304 while (unlikely(open_files > new_fdt->max_fds)) {
305 spin_unlock(&oldf->file_lock);
306
307 if (new_fdt != &newf->fdtab)
308 __free_fdtable(new_fdt);
309
310 new_fdt = alloc_fdtable(open_files - 1);
311 if (!new_fdt) {
312 *errorp = -ENOMEM;
313 goto out_release;
314 }
315
316
317 if (unlikely(new_fdt->max_fds < open_files)) {
318 __free_fdtable(new_fdt);
319 *errorp = -EMFILE;
320 goto out_release;
321 }
322
323
324
325
326
327
328 spin_lock(&oldf->file_lock);
329 old_fdt = files_fdtable(oldf);
330 open_files = count_open_files(old_fdt);
331 }
332
333 copy_fd_bitmaps(new_fdt, old_fdt, open_files);
334
335 old_fds = old_fdt->fd;
336 new_fds = new_fdt->fd;
337
338 for (i = open_files; i != 0; i--) {
339 struct file *f = *old_fds++;
340 if (f) {
341 get_file(f);
342 } else {
343
344
345
346
347
348
349 __clear_open_fd(open_files - i, new_fdt);
350 }
351 rcu_assign_pointer(*new_fds++, f);
352 }
353 spin_unlock(&oldf->file_lock);
354
355
356 memset(new_fds, 0, (new_fdt->max_fds - open_files) * sizeof(struct file *));
357
358 rcu_assign_pointer(newf->fdt, new_fdt);
359
360 return newf;
361
362out_release:
363 kmem_cache_free(files_cachep, newf);
364out:
365 return NULL;
366}
367
368static struct fdtable *close_files(struct files_struct * files)
369{
370
371
372
373
374
375 struct fdtable *fdt = rcu_dereference_raw(files->fdt);
376 unsigned int i, j = 0;
377
378 for (;;) {
379 unsigned long set;
380 i = j * BITS_PER_LONG;
381 if (i >= fdt->max_fds)
382 break;
383 set = fdt->open_fds[j++];
384 while (set) {
385 if (set & 1) {
386 struct file * file = xchg(&fdt->fd[i], NULL);
387 if (file) {
388 filp_close(file, files);
389 cond_resched();
390 }
391 }
392 i++;
393 set >>= 1;
394 }
395 }
396
397 return fdt;
398}
399
400struct files_struct *get_files_struct(struct task_struct *task)
401{
402 struct files_struct *files;
403
404 task_lock(task);
405 files = task->files;
406 if (files)
407 atomic_inc(&files->count);
408 task_unlock(task);
409
410 return files;
411}
412
413void put_files_struct(struct files_struct *files)
414{
415 if (atomic_dec_and_test(&files->count)) {
416 struct fdtable *fdt = close_files(files);
417
418
419 if (fdt != &files->fdtab)
420 __free_fdtable(fdt);
421 kmem_cache_free(files_cachep, files);
422 }
423}
424
425void reset_files_struct(struct files_struct *files)
426{
427 struct task_struct *tsk = current;
428 struct files_struct *old;
429
430 old = tsk->files;
431 task_lock(tsk);
432 tsk->files = files;
433 task_unlock(tsk);
434 put_files_struct(old);
435}
436
437void exit_files(struct task_struct *tsk)
438{
439 struct files_struct * files = tsk->files;
440
441 if (files) {
442 task_lock(tsk);
443 tsk->files = NULL;
444 task_unlock(tsk);
445 put_files_struct(files);
446 }
447}
448
449struct files_struct init_files = {
450 .count = ATOMIC_INIT(1),
451 .fdt = &init_files.fdtab,
452 .fdtab = {
453 .max_fds = NR_OPEN_DEFAULT,
454 .fd = &init_files.fd_array[0],
455 .close_on_exec = init_files.close_on_exec_init,
456 .open_fds = init_files.open_fds_init,
457 .full_fds_bits = init_files.full_fds_bits_init,
458 },
459 .file_lock = __SPIN_LOCK_UNLOCKED(init_files.file_lock),
460};
461
462static unsigned int find_next_fd(struct fdtable *fdt, unsigned int start)
463{
464 unsigned int maxfd = fdt->max_fds;
465 unsigned int maxbit = maxfd / BITS_PER_LONG;
466 unsigned int bitbit = start / BITS_PER_LONG;
467
468 bitbit = find_next_zero_bit(fdt->full_fds_bits, maxbit, bitbit) * BITS_PER_LONG;
469 if (bitbit > maxfd)
470 return maxfd;
471 if (bitbit > start)
472 start = bitbit;
473 return find_next_zero_bit(fdt->open_fds, maxfd, start);
474}
475
476
477
478
479int __alloc_fd(struct files_struct *files,
480 unsigned start, unsigned end, unsigned flags)
481{
482 unsigned int fd;
483 int error;
484 struct fdtable *fdt;
485
486 spin_lock(&files->file_lock);
487repeat:
488 fdt = files_fdtable(files);
489 fd = start;
490 if (fd < files->next_fd)
491 fd = files->next_fd;
492
493 if (fd < fdt->max_fds)
494 fd = find_next_fd(fdt, fd);
495
496
497
498
499
500 error = -EMFILE;
501 if (fd >= end)
502 goto out;
503
504 error = expand_files(files, fd);
505 if (error < 0)
506 goto out;
507
508
509
510
511
512 if (error)
513 goto repeat;
514
515 if (start <= files->next_fd)
516 files->next_fd = fd + 1;
517
518 __set_open_fd(fd, fdt);
519 if (flags & O_CLOEXEC)
520 __set_close_on_exec(fd, fdt);
521 else
522 __clear_close_on_exec(fd, fdt);
523 error = fd;
524#if 1
525
526 if (rcu_access_pointer(fdt->fd[fd]) != NULL) {
527 printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
528 rcu_assign_pointer(fdt->fd[fd], NULL);
529 }
530#endif
531
532out:
533 spin_unlock(&files->file_lock);
534 return error;
535}
536
537static int alloc_fd(unsigned start, unsigned flags)
538{
539 return __alloc_fd(current->files, start, rlimit(RLIMIT_NOFILE), flags);
540}
541
542int get_unused_fd_flags(unsigned flags)
543{
544 return __alloc_fd(current->files, 0, rlimit(RLIMIT_NOFILE), flags);
545}
546EXPORT_SYMBOL(get_unused_fd_flags);
547
548static void __put_unused_fd(struct files_struct *files, unsigned int fd)
549{
550 struct fdtable *fdt = files_fdtable(files);
551 __clear_open_fd(fd, fdt);
552 if (fd < files->next_fd)
553 files->next_fd = fd;
554}
555
556void put_unused_fd(unsigned int fd)
557{
558 struct files_struct *files = current->files;
559 spin_lock(&files->file_lock);
560 __put_unused_fd(files, fd);
561 spin_unlock(&files->file_lock);
562}
563
564EXPORT_SYMBOL(put_unused_fd);
565
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585
586void __fd_install(struct files_struct *files, unsigned int fd,
587 struct file *file)
588{
589 struct fdtable *fdt;
590
591 rcu_read_lock_sched();
592
593 if (unlikely(files->resize_in_progress)) {
594 rcu_read_unlock_sched();
595 spin_lock(&files->file_lock);
596 fdt = files_fdtable(files);
597 BUG_ON(fdt->fd[fd] != NULL);
598 rcu_assign_pointer(fdt->fd[fd], file);
599 spin_unlock(&files->file_lock);
600 return;
601 }
602
603 smp_rmb();
604 fdt = rcu_dereference_sched(files->fdt);
605 BUG_ON(fdt->fd[fd] != NULL);
606 rcu_assign_pointer(fdt->fd[fd], file);
607 rcu_read_unlock_sched();
608}
609
610void fd_install(unsigned int fd, struct file *file)
611{
612 __fd_install(current->files, fd, file);
613}
614
615EXPORT_SYMBOL(fd_install);
616
617
618
619
620int __close_fd(struct files_struct *files, unsigned fd)
621{
622 struct file *file;
623 struct fdtable *fdt;
624
625 spin_lock(&files->file_lock);
626 fdt = files_fdtable(files);
627 if (fd >= fdt->max_fds)
628 goto out_unlock;
629 file = fdt->fd[fd];
630 if (!file)
631 goto out_unlock;
632 rcu_assign_pointer(fdt->fd[fd], NULL);
633 __put_unused_fd(files, fd);
634 spin_unlock(&files->file_lock);
635 return filp_close(file, files);
636
637out_unlock:
638 spin_unlock(&files->file_lock);
639 return -EBADF;
640}
641EXPORT_SYMBOL(__close_fd);
642
643void do_close_on_exec(struct files_struct *files)
644{
645 unsigned i;
646 struct fdtable *fdt;
647
648
649 spin_lock(&files->file_lock);
650 for (i = 0; ; i++) {
651 unsigned long set;
652 unsigned fd = i * BITS_PER_LONG;
653 fdt = files_fdtable(files);
654 if (fd >= fdt->max_fds)
655 break;
656 set = fdt->close_on_exec[i];
657 if (!set)
658 continue;
659 fdt->close_on_exec[i] = 0;
660 for ( ; set ; fd++, set >>= 1) {
661 struct file *file;
662 if (!(set & 1))
663 continue;
664 file = fdt->fd[fd];
665 if (!file)
666 continue;
667 rcu_assign_pointer(fdt->fd[fd], NULL);
668 __put_unused_fd(files, fd);
669 spin_unlock(&files->file_lock);
670 filp_close(file, files);
671 cond_resched();
672 spin_lock(&files->file_lock);
673 }
674
675 }
676 spin_unlock(&files->file_lock);
677}
678
679static struct file *__fget(unsigned int fd, fmode_t mask)
680{
681 struct files_struct *files = current->files;
682 struct file *file;
683
684 rcu_read_lock();
685loop:
686 file = fcheck_files(files, fd);
687 if (file) {
688
689
690
691
692 if (file->f_mode & mask)
693 file = NULL;
694 else if (!get_file_rcu(file))
695 goto loop;
696 }
697 rcu_read_unlock();
698
699 return file;
700}
701
702struct file *fget(unsigned int fd)
703{
704 return __fget(fd, FMODE_PATH);
705}
706EXPORT_SYMBOL(fget);
707
708struct file *fget_raw(unsigned int fd)
709{
710 return __fget(fd, 0);
711}
712EXPORT_SYMBOL(fget_raw);
713
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719
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721
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723
724
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727
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729
730static unsigned long __fget_light(unsigned int fd, fmode_t mask)
731{
732 struct files_struct *files = current->files;
733 struct file *file;
734
735 if (atomic_read(&files->count) == 1) {
736 file = __fcheck_files(files, fd);
737 if (!file || unlikely(file->f_mode & mask))
738 return 0;
739 return (unsigned long)file;
740 } else {
741 file = __fget(fd, mask);
742 if (!file)
743 return 0;
744 return FDPUT_FPUT | (unsigned long)file;
745 }
746}
747unsigned long __fdget(unsigned int fd)
748{
749 return __fget_light(fd, FMODE_PATH);
750}
751EXPORT_SYMBOL(__fdget);
752
753unsigned long __fdget_raw(unsigned int fd)
754{
755 return __fget_light(fd, 0);
756}
757
758unsigned long __fdget_pos(unsigned int fd)
759{
760 unsigned long v = __fdget(fd);
761 struct file *file = (struct file *)(v & ~3);
762
763 if (file && (file->f_mode & FMODE_ATOMIC_POS)) {
764 if (file_count(file) > 1) {
765 v |= FDPUT_POS_UNLOCK;
766 mutex_lock(&file->f_pos_lock);
767 }
768 }
769 return v;
770}
771
772void __f_unlock_pos(struct file *f)
773{
774 mutex_unlock(&f->f_pos_lock);
775}
776
777
778
779
780
781
782
783void set_close_on_exec(unsigned int fd, int flag)
784{
785 struct files_struct *files = current->files;
786 struct fdtable *fdt;
787 spin_lock(&files->file_lock);
788 fdt = files_fdtable(files);
789 if (flag)
790 __set_close_on_exec(fd, fdt);
791 else
792 __clear_close_on_exec(fd, fdt);
793 spin_unlock(&files->file_lock);
794}
795
796bool get_close_on_exec(unsigned int fd)
797{
798 struct files_struct *files = current->files;
799 struct fdtable *fdt;
800 bool res;
801 rcu_read_lock();
802 fdt = files_fdtable(files);
803 res = close_on_exec(fd, fdt);
804 rcu_read_unlock();
805 return res;
806}
807
808static int do_dup2(struct files_struct *files,
809 struct file *file, unsigned fd, unsigned flags)
810__releases(&files->file_lock)
811{
812 struct file *tofree;
813 struct fdtable *fdt;
814
815
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819
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821
822
823
824
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826
827
828
829 fdt = files_fdtable(files);
830 tofree = fdt->fd[fd];
831 if (!tofree && fd_is_open(fd, fdt))
832 goto Ebusy;
833 get_file(file);
834 rcu_assign_pointer(fdt->fd[fd], file);
835 __set_open_fd(fd, fdt);
836 if (flags & O_CLOEXEC)
837 __set_close_on_exec(fd, fdt);
838 else
839 __clear_close_on_exec(fd, fdt);
840 spin_unlock(&files->file_lock);
841
842 if (tofree)
843 filp_close(tofree, files);
844
845 return fd;
846
847Ebusy:
848 spin_unlock(&files->file_lock);
849 return -EBUSY;
850}
851
852int replace_fd(unsigned fd, struct file *file, unsigned flags)
853{
854 int err;
855 struct files_struct *files = current->files;
856
857 if (!file)
858 return __close_fd(files, fd);
859
860 if (fd >= rlimit(RLIMIT_NOFILE))
861 return -EBADF;
862
863 spin_lock(&files->file_lock);
864 err = expand_files(files, fd);
865 if (unlikely(err < 0))
866 goto out_unlock;
867 return do_dup2(files, file, fd, flags);
868
869out_unlock:
870 spin_unlock(&files->file_lock);
871 return err;
872}
873
874static int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
875{
876 int err = -EBADF;
877 struct file *file;
878 struct files_struct *files = current->files;
879
880 if ((flags & ~O_CLOEXEC) != 0)
881 return -EINVAL;
882
883 if (unlikely(oldfd == newfd))
884 return -EINVAL;
885
886 if (newfd >= rlimit(RLIMIT_NOFILE))
887 return -EBADF;
888
889 spin_lock(&files->file_lock);
890 err = expand_files(files, newfd);
891 file = fcheck(oldfd);
892 if (unlikely(!file))
893 goto Ebadf;
894 if (unlikely(err < 0)) {
895 if (err == -EMFILE)
896 goto Ebadf;
897 goto out_unlock;
898 }
899 return do_dup2(files, file, newfd, flags);
900
901Ebadf:
902 err = -EBADF;
903out_unlock:
904 spin_unlock(&files->file_lock);
905 return err;
906}
907
908SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
909{
910 return ksys_dup3(oldfd, newfd, flags);
911}
912
913SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
914{
915 if (unlikely(newfd == oldfd)) {
916 struct files_struct *files = current->files;
917 int retval = oldfd;
918
919 rcu_read_lock();
920 if (!fcheck_files(files, oldfd))
921 retval = -EBADF;
922 rcu_read_unlock();
923 return retval;
924 }
925 return ksys_dup3(oldfd, newfd, 0);
926}
927
928int ksys_dup(unsigned int fildes)
929{
930 int ret = -EBADF;
931 struct file *file = fget_raw(fildes);
932
933 if (file) {
934 ret = get_unused_fd_flags(0);
935 if (ret >= 0)
936 fd_install(ret, file);
937 else
938 fput(file);
939 }
940 return ret;
941}
942
943SYSCALL_DEFINE1(dup, unsigned int, fildes)
944{
945 return ksys_dup(fildes);
946}
947
948int f_dupfd(unsigned int from, struct file *file, unsigned flags)
949{
950 int err;
951 if (from >= rlimit(RLIMIT_NOFILE))
952 return -EINVAL;
953 err = alloc_fd(from, flags);
954 if (err >= 0) {
955 get_file(file);
956 fd_install(err, file);
957 }
958 return err;
959}
960
961int iterate_fd(struct files_struct *files, unsigned n,
962 int (*f)(const void *, struct file *, unsigned),
963 const void *p)
964{
965 struct fdtable *fdt;
966 int res = 0;
967 if (!files)
968 return 0;
969 spin_lock(&files->file_lock);
970 for (fdt = files_fdtable(files); n < fdt->max_fds; n++) {
971 struct file *file;
972 file = rcu_dereference_check_fdtable(files, fdt->fd[n]);
973 if (!file)
974 continue;
975 res = f(p, file, n);
976 if (res)
977 break;
978 }
979 spin_unlock(&files->file_lock);
980 return res;
981}
982EXPORT_SYMBOL(iterate_fd);
983