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8
9#include <linux/syscalls.h>
10#include <linux/export.h>
11#include <linux/fs.h>
12#include <linux/mm.h>
13#include <linux/mmzone.h>
14#include <linux/time.h>
15#include <linux/sched.h>
16#include <linux/slab.h>
17#include <linux/vmalloc.h>
18#include <linux/file.h>
19#include <linux/fdtable.h>
20#include <linux/bitops.h>
21#include <linux/interrupt.h>
22#include <linux/spinlock.h>
23#include <linux/rcupdate.h>
24#include <linux/workqueue.h>
25
26int sysctl_nr_open __read_mostly = 1024*1024;
27int sysctl_nr_open_min = BITS_PER_LONG;
28
29#define __const_min(x, y) ((x) < (y) ? (x) : (y))
30int sysctl_nr_open_max = __const_min(INT_MAX, ~(size_t)0/sizeof(void *)) &
31 -BITS_PER_LONG;
32
33static void *alloc_fdmem(size_t size)
34{
35
36
37
38
39 if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
40 void *data = kmalloc(size, GFP_KERNEL_ACCOUNT |
41 __GFP_NOWARN | __GFP_NORETRY);
42 if (data != NULL)
43 return data;
44 }
45 return __vmalloc(size, GFP_KERNEL_ACCOUNT | __GFP_HIGHMEM, PAGE_KERNEL);
46}
47
48static void __free_fdtable(struct fdtable *fdt)
49{
50 kvfree(fdt->fd);
51 kvfree(fdt->open_fds);
52 kfree(fdt);
53}
54
55static void free_fdtable_rcu(struct rcu_head *rcu)
56{
57 __free_fdtable(container_of(rcu, struct fdtable, rcu));
58}
59
60#define BITBIT_NR(nr) BITS_TO_LONGS(BITS_TO_LONGS(nr))
61#define BITBIT_SIZE(nr) (BITBIT_NR(nr) * sizeof(long))
62
63
64
65
66
67
68static void copy_fd_bitmaps(struct fdtable *nfdt, struct fdtable *ofdt,
69 unsigned int count)
70{
71 unsigned int cpy, set;
72
73 cpy = count / BITS_PER_BYTE;
74 set = (nfdt->max_fds - count) / BITS_PER_BYTE;
75 memcpy(nfdt->open_fds, ofdt->open_fds, cpy);
76 memset((char *)nfdt->open_fds + cpy, 0, set);
77 memcpy(nfdt->close_on_exec, ofdt->close_on_exec, cpy);
78 memset((char *)nfdt->close_on_exec + cpy, 0, set);
79
80 cpy = BITBIT_SIZE(count);
81 set = BITBIT_SIZE(nfdt->max_fds) - cpy;
82 memcpy(nfdt->full_fds_bits, ofdt->full_fds_bits, cpy);
83 memset((char *)nfdt->full_fds_bits + cpy, 0, set);
84}
85
86
87
88
89
90static void copy_fdtable(struct fdtable *nfdt, struct fdtable *ofdt)
91{
92 unsigned int cpy, set;
93
94 BUG_ON(nfdt->max_fds < ofdt->max_fds);
95
96 cpy = ofdt->max_fds * sizeof(struct file *);
97 set = (nfdt->max_fds - ofdt->max_fds) * sizeof(struct file *);
98 memcpy(nfdt->fd, ofdt->fd, cpy);
99 memset((char *)nfdt->fd + cpy, 0, set);
100
101 copy_fd_bitmaps(nfdt, ofdt, ofdt->max_fds);
102}
103
104static struct fdtable * alloc_fdtable(unsigned int nr)
105{
106 struct fdtable *fdt;
107 void *data;
108
109
110
111
112
113
114
115
116 nr /= (1024 / sizeof(struct file *));
117 nr = roundup_pow_of_two(nr + 1);
118 nr *= (1024 / sizeof(struct file *));
119
120
121
122
123
124
125
126
127 if (unlikely(nr > sysctl_nr_open))
128 nr = ((sysctl_nr_open - 1) | (BITS_PER_LONG - 1)) + 1;
129
130 fdt = kmalloc(sizeof(struct fdtable), GFP_KERNEL_ACCOUNT);
131 if (!fdt)
132 goto out;
133 fdt->max_fds = nr;
134 data = alloc_fdmem(nr * sizeof(struct file *));
135 if (!data)
136 goto out_fdt;
137 fdt->fd = data;
138
139 data = alloc_fdmem(max_t(size_t,
140 2 * nr / BITS_PER_BYTE + BITBIT_SIZE(nr), L1_CACHE_BYTES));
141 if (!data)
142 goto out_arr;
143 fdt->open_fds = data;
144 data += nr / BITS_PER_BYTE;
145 fdt->close_on_exec = data;
146 data += nr / BITS_PER_BYTE;
147 fdt->full_fds_bits = data;
148
149 return fdt;
150
151out_arr:
152 kvfree(fdt->fd);
153out_fdt:
154 kfree(fdt);
155out:
156 return NULL;
157}
158
159
160
161
162
163
164
165
166static int expand_fdtable(struct files_struct *files, int nr)
167 __releases(files->file_lock)
168 __acquires(files->file_lock)
169{
170 struct fdtable *new_fdt, *cur_fdt;
171
172 spin_unlock(&files->file_lock);
173 new_fdt = alloc_fdtable(nr);
174
175
176
177
178 if (atomic_read(&files->count) > 1)
179 synchronize_sched();
180
181 spin_lock(&files->file_lock);
182 if (!new_fdt)
183 return -ENOMEM;
184
185
186
187
188 if (unlikely(new_fdt->max_fds <= nr)) {
189 __free_fdtable(new_fdt);
190 return -EMFILE;
191 }
192 cur_fdt = files_fdtable(files);
193 BUG_ON(nr < cur_fdt->max_fds);
194 copy_fdtable(new_fdt, cur_fdt);
195 rcu_assign_pointer(files->fdt, new_fdt);
196 if (cur_fdt != &files->fdtab)
197 call_rcu(&cur_fdt->rcu, free_fdtable_rcu);
198
199 smp_wmb();
200 return 1;
201}
202
203
204
205
206
207
208
209
210
211static int expand_files(struct files_struct *files, int nr)
212 __releases(files->file_lock)
213 __acquires(files->file_lock)
214{
215 struct fdtable *fdt;
216 int expanded = 0;
217
218repeat:
219 fdt = files_fdtable(files);
220
221
222 if (nr < fdt->max_fds)
223 return expanded;
224
225
226 if (nr >= sysctl_nr_open)
227 return -EMFILE;
228
229 if (unlikely(files->resize_in_progress)) {
230 spin_unlock(&files->file_lock);
231 expanded = 1;
232 wait_event(files->resize_wait, !files->resize_in_progress);
233 spin_lock(&files->file_lock);
234 goto repeat;
235 }
236
237
238 files->resize_in_progress = true;
239 expanded = expand_fdtable(files, nr);
240 files->resize_in_progress = false;
241
242 wake_up_all(&files->resize_wait);
243 return expanded;
244}
245
246static inline void __set_close_on_exec(int fd, struct fdtable *fdt)
247{
248 __set_bit(fd, fdt->close_on_exec);
249}
250
251static inline void __clear_close_on_exec(int fd, struct fdtable *fdt)
252{
253 if (test_bit(fd, fdt->close_on_exec))
254 __clear_bit(fd, fdt->close_on_exec);
255}
256
257static inline void __set_open_fd(unsigned int fd, struct fdtable *fdt)
258{
259 __set_bit(fd, fdt->open_fds);
260 fd /= BITS_PER_LONG;
261 if (!~fdt->open_fds[fd])
262 __set_bit(fd, fdt->full_fds_bits);
263}
264
265static inline void __clear_open_fd(unsigned int fd, struct fdtable *fdt)
266{
267 __clear_bit(fd, fdt->open_fds);
268 __clear_bit(fd / BITS_PER_LONG, fdt->full_fds_bits);
269}
270
271static int count_open_files(struct fdtable *fdt)
272{
273 int size = fdt->max_fds;
274 int i;
275
276
277 for (i = size / BITS_PER_LONG; i > 0; ) {
278 if (fdt->open_fds[--i])
279 break;
280 }
281 i = (i + 1) * BITS_PER_LONG;
282 return i;
283}
284
285
286
287
288
289
290struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
291{
292 struct files_struct *newf;
293 struct file **old_fds, **new_fds;
294 int open_files, i;
295 struct fdtable *old_fdt, *new_fdt;
296
297 *errorp = -ENOMEM;
298 newf = kmem_cache_alloc(files_cachep, GFP_KERNEL);
299 if (!newf)
300 goto out;
301
302 atomic_set(&newf->count, 1);
303
304 spin_lock_init(&newf->file_lock);
305 newf->resize_in_progress = false;
306 init_waitqueue_head(&newf->resize_wait);
307 newf->next_fd = 0;
308 new_fdt = &newf->fdtab;
309 new_fdt->max_fds = NR_OPEN_DEFAULT;
310 new_fdt->close_on_exec = newf->close_on_exec_init;
311 new_fdt->open_fds = newf->open_fds_init;
312 new_fdt->full_fds_bits = newf->full_fds_bits_init;
313 new_fdt->fd = &newf->fd_array[0];
314
315 spin_lock(&oldf->file_lock);
316 old_fdt = files_fdtable(oldf);
317 open_files = count_open_files(old_fdt);
318
319
320
321
322 while (unlikely(open_files > new_fdt->max_fds)) {
323 spin_unlock(&oldf->file_lock);
324
325 if (new_fdt != &newf->fdtab)
326 __free_fdtable(new_fdt);
327
328 new_fdt = alloc_fdtable(open_files - 1);
329 if (!new_fdt) {
330 *errorp = -ENOMEM;
331 goto out_release;
332 }
333
334
335 if (unlikely(new_fdt->max_fds < open_files)) {
336 __free_fdtable(new_fdt);
337 *errorp = -EMFILE;
338 goto out_release;
339 }
340
341
342
343
344
345
346 spin_lock(&oldf->file_lock);
347 old_fdt = files_fdtable(oldf);
348 open_files = count_open_files(old_fdt);
349 }
350
351 copy_fd_bitmaps(new_fdt, old_fdt, open_files);
352
353 old_fds = old_fdt->fd;
354 new_fds = new_fdt->fd;
355
356 for (i = open_files; i != 0; i--) {
357 struct file *f = *old_fds++;
358 if (f) {
359 get_file(f);
360 } else {
361
362
363
364
365
366
367 __clear_open_fd(open_files - i, new_fdt);
368 }
369 rcu_assign_pointer(*new_fds++, f);
370 }
371 spin_unlock(&oldf->file_lock);
372
373
374 memset(new_fds, 0, (new_fdt->max_fds - open_files) * sizeof(struct file *));
375
376 rcu_assign_pointer(newf->fdt, new_fdt);
377
378 return newf;
379
380out_release:
381 kmem_cache_free(files_cachep, newf);
382out:
383 return NULL;
384}
385
386static struct fdtable *close_files(struct files_struct * files)
387{
388
389
390
391
392
393 struct fdtable *fdt = rcu_dereference_raw(files->fdt);
394 int i, j = 0;
395
396 for (;;) {
397 unsigned long set;
398 i = j * BITS_PER_LONG;
399 if (i >= fdt->max_fds)
400 break;
401 set = fdt->open_fds[j++];
402 while (set) {
403 if (set & 1) {
404 struct file * file = xchg(&fdt->fd[i], NULL);
405 if (file) {
406 filp_close(file, files);
407 cond_resched_rcu_qs();
408 }
409 }
410 i++;
411 set >>= 1;
412 }
413 }
414
415 return fdt;
416}
417
418struct files_struct *get_files_struct(struct task_struct *task)
419{
420 struct files_struct *files;
421
422 task_lock(task);
423 files = task->files;
424 if (files)
425 atomic_inc(&files->count);
426 task_unlock(task);
427
428 return files;
429}
430
431void put_files_struct(struct files_struct *files)
432{
433 if (atomic_dec_and_test(&files->count)) {
434 struct fdtable *fdt = close_files(files);
435
436
437 if (fdt != &files->fdtab)
438 __free_fdtable(fdt);
439 kmem_cache_free(files_cachep, files);
440 }
441}
442
443void reset_files_struct(struct files_struct *files)
444{
445 struct task_struct *tsk = current;
446 struct files_struct *old;
447
448 old = tsk->files;
449 task_lock(tsk);
450 tsk->files = files;
451 task_unlock(tsk);
452 put_files_struct(old);
453}
454
455void exit_files(struct task_struct *tsk)
456{
457 struct files_struct * files = tsk->files;
458
459 if (files) {
460 task_lock(tsk);
461 tsk->files = NULL;
462 task_unlock(tsk);
463 put_files_struct(files);
464 }
465}
466
467struct files_struct init_files = {
468 .count = ATOMIC_INIT(1),
469 .fdt = &init_files.fdtab,
470 .fdtab = {
471 .max_fds = NR_OPEN_DEFAULT,
472 .fd = &init_files.fd_array[0],
473 .close_on_exec = init_files.close_on_exec_init,
474 .open_fds = init_files.open_fds_init,
475 .full_fds_bits = init_files.full_fds_bits_init,
476 },
477 .file_lock = __SPIN_LOCK_UNLOCKED(init_files.file_lock),
478};
479
480static unsigned long find_next_fd(struct fdtable *fdt, unsigned long start)
481{
482 unsigned long maxfd = fdt->max_fds;
483 unsigned long maxbit = maxfd / BITS_PER_LONG;
484 unsigned long bitbit = start / BITS_PER_LONG;
485
486 bitbit = find_next_zero_bit(fdt->full_fds_bits, maxbit, bitbit) * BITS_PER_LONG;
487 if (bitbit > maxfd)
488 return maxfd;
489 if (bitbit > start)
490 start = bitbit;
491 return find_next_zero_bit(fdt->open_fds, maxfd, start);
492}
493
494
495
496
497int __alloc_fd(struct files_struct *files,
498 unsigned start, unsigned end, unsigned flags)
499{
500 unsigned int fd;
501 int error;
502 struct fdtable *fdt;
503
504 spin_lock(&files->file_lock);
505repeat:
506 fdt = files_fdtable(files);
507 fd = start;
508 if (fd < files->next_fd)
509 fd = files->next_fd;
510
511 if (fd < fdt->max_fds)
512 fd = find_next_fd(fdt, fd);
513
514
515
516
517
518 error = -EMFILE;
519 if (fd >= end)
520 goto out;
521
522 error = expand_files(files, fd);
523 if (error < 0)
524 goto out;
525
526
527
528
529
530 if (error)
531 goto repeat;
532
533 if (start <= files->next_fd)
534 files->next_fd = fd + 1;
535
536 __set_open_fd(fd, fdt);
537 if (flags & O_CLOEXEC)
538 __set_close_on_exec(fd, fdt);
539 else
540 __clear_close_on_exec(fd, fdt);
541 error = fd;
542#if 1
543
544 if (rcu_access_pointer(fdt->fd[fd]) != NULL) {
545 printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
546 rcu_assign_pointer(fdt->fd[fd], NULL);
547 }
548#endif
549
550out:
551 spin_unlock(&files->file_lock);
552 return error;
553}
554
555static int alloc_fd(unsigned start, unsigned flags)
556{
557 return __alloc_fd(current->files, start, rlimit(RLIMIT_NOFILE), flags);
558}
559
560int get_unused_fd_flags(unsigned flags)
561{
562 return __alloc_fd(current->files, 0, rlimit(RLIMIT_NOFILE), flags);
563}
564EXPORT_SYMBOL(get_unused_fd_flags);
565
566static void __put_unused_fd(struct files_struct *files, unsigned int fd)
567{
568 struct fdtable *fdt = files_fdtable(files);
569 __clear_open_fd(fd, fdt);
570 if (fd < files->next_fd)
571 files->next_fd = fd;
572}
573
574void put_unused_fd(unsigned int fd)
575{
576 struct files_struct *files = current->files;
577 spin_lock(&files->file_lock);
578 __put_unused_fd(files, fd);
579 spin_unlock(&files->file_lock);
580}
581
582EXPORT_SYMBOL(put_unused_fd);
583
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598
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600
601
602
603
604void __fd_install(struct files_struct *files, unsigned int fd,
605 struct file *file)
606{
607 struct fdtable *fdt;
608
609 might_sleep();
610 rcu_read_lock_sched();
611
612 while (unlikely(files->resize_in_progress)) {
613 rcu_read_unlock_sched();
614 wait_event(files->resize_wait, !files->resize_in_progress);
615 rcu_read_lock_sched();
616 }
617
618 smp_rmb();
619 fdt = rcu_dereference_sched(files->fdt);
620 BUG_ON(fdt->fd[fd] != NULL);
621 rcu_assign_pointer(fdt->fd[fd], file);
622 rcu_read_unlock_sched();
623}
624
625void fd_install(unsigned int fd, struct file *file)
626{
627 __fd_install(current->files, fd, file);
628}
629
630EXPORT_SYMBOL(fd_install);
631
632
633
634
635int __close_fd(struct files_struct *files, unsigned fd)
636{
637 struct file *file;
638 struct fdtable *fdt;
639
640 spin_lock(&files->file_lock);
641 fdt = files_fdtable(files);
642 if (fd >= fdt->max_fds)
643 goto out_unlock;
644 file = fdt->fd[fd];
645 if (!file)
646 goto out_unlock;
647 rcu_assign_pointer(fdt->fd[fd], NULL);
648 __clear_close_on_exec(fd, fdt);
649 __put_unused_fd(files, fd);
650 spin_unlock(&files->file_lock);
651 return filp_close(file, files);
652
653out_unlock:
654 spin_unlock(&files->file_lock);
655 return -EBADF;
656}
657
658void do_close_on_exec(struct files_struct *files)
659{
660 unsigned i;
661 struct fdtable *fdt;
662
663
664 spin_lock(&files->file_lock);
665 for (i = 0; ; i++) {
666 unsigned long set;
667 unsigned fd = i * BITS_PER_LONG;
668 fdt = files_fdtable(files);
669 if (fd >= fdt->max_fds)
670 break;
671 set = fdt->close_on_exec[i];
672 if (!set)
673 continue;
674 fdt->close_on_exec[i] = 0;
675 for ( ; set ; fd++, set >>= 1) {
676 struct file *file;
677 if (!(set & 1))
678 continue;
679 file = fdt->fd[fd];
680 if (!file)
681 continue;
682 rcu_assign_pointer(fdt->fd[fd], NULL);
683 __put_unused_fd(files, fd);
684 spin_unlock(&files->file_lock);
685 filp_close(file, files);
686 cond_resched();
687 spin_lock(&files->file_lock);
688 }
689
690 }
691 spin_unlock(&files->file_lock);
692}
693
694static struct file *__fget(unsigned int fd, fmode_t mask)
695{
696 struct files_struct *files = current->files;
697 struct file *file;
698
699 rcu_read_lock();
700loop:
701 file = fcheck_files(files, fd);
702 if (file) {
703
704
705
706
707 if (file->f_mode & mask)
708 file = NULL;
709 else if (!get_file_rcu(file))
710 goto loop;
711 }
712 rcu_read_unlock();
713
714 return file;
715}
716
717struct file *fget(unsigned int fd)
718{
719 return __fget(fd, FMODE_PATH);
720}
721EXPORT_SYMBOL(fget);
722
723struct file *fget_raw(unsigned int fd)
724{
725 return __fget(fd, 0);
726}
727EXPORT_SYMBOL(fget_raw);
728
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741
742
743
744
745static unsigned long __fget_light(unsigned int fd, fmode_t mask)
746{
747 struct files_struct *files = current->files;
748 struct file *file;
749
750 if (atomic_read(&files->count) == 1) {
751 file = __fcheck_files(files, fd);
752 if (!file || unlikely(file->f_mode & mask))
753 return 0;
754 return (unsigned long)file;
755 } else {
756 file = __fget(fd, mask);
757 if (!file)
758 return 0;
759 return FDPUT_FPUT | (unsigned long)file;
760 }
761}
762unsigned long __fdget(unsigned int fd)
763{
764 return __fget_light(fd, FMODE_PATH);
765}
766EXPORT_SYMBOL(__fdget);
767
768unsigned long __fdget_raw(unsigned int fd)
769{
770 return __fget_light(fd, 0);
771}
772
773unsigned long __fdget_pos(unsigned int fd)
774{
775 unsigned long v = __fdget(fd);
776 struct file *file = (struct file *)(v & ~3);
777
778 if (file && (file->f_mode & FMODE_ATOMIC_POS)) {
779 if (file_count(file) > 1) {
780 v |= FDPUT_POS_UNLOCK;
781 mutex_lock(&file->f_pos_lock);
782 }
783 }
784 return v;
785}
786
787
788
789
790
791
792
793void set_close_on_exec(unsigned int fd, int flag)
794{
795 struct files_struct *files = current->files;
796 struct fdtable *fdt;
797 spin_lock(&files->file_lock);
798 fdt = files_fdtable(files);
799 if (flag)
800 __set_close_on_exec(fd, fdt);
801 else
802 __clear_close_on_exec(fd, fdt);
803 spin_unlock(&files->file_lock);
804}
805
806bool get_close_on_exec(unsigned int fd)
807{
808 struct files_struct *files = current->files;
809 struct fdtable *fdt;
810 bool res;
811 rcu_read_lock();
812 fdt = files_fdtable(files);
813 res = close_on_exec(fd, fdt);
814 rcu_read_unlock();
815 return res;
816}
817
818static int do_dup2(struct files_struct *files,
819 struct file *file, unsigned fd, unsigned flags)
820__releases(&files->file_lock)
821{
822 struct file *tofree;
823 struct fdtable *fdt;
824
825
826
827
828
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831
832
833
834
835
836
837
838
839 fdt = files_fdtable(files);
840 tofree = fdt->fd[fd];
841 if (!tofree && fd_is_open(fd, fdt))
842 goto Ebusy;
843 get_file(file);
844 rcu_assign_pointer(fdt->fd[fd], file);
845 __set_open_fd(fd, fdt);
846 if (flags & O_CLOEXEC)
847 __set_close_on_exec(fd, fdt);
848 else
849 __clear_close_on_exec(fd, fdt);
850 spin_unlock(&files->file_lock);
851
852 if (tofree)
853 filp_close(tofree, files);
854
855 return fd;
856
857Ebusy:
858 spin_unlock(&files->file_lock);
859 return -EBUSY;
860}
861
862int replace_fd(unsigned fd, struct file *file, unsigned flags)
863{
864 int err;
865 struct files_struct *files = current->files;
866
867 if (!file)
868 return __close_fd(files, fd);
869
870 if (fd >= rlimit(RLIMIT_NOFILE))
871 return -EBADF;
872
873 spin_lock(&files->file_lock);
874 err = expand_files(files, fd);
875 if (unlikely(err < 0))
876 goto out_unlock;
877 return do_dup2(files, file, fd, flags);
878
879out_unlock:
880 spin_unlock(&files->file_lock);
881 return err;
882}
883
884SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
885{
886 int err = -EBADF;
887 struct file *file;
888 struct files_struct *files = current->files;
889
890 if ((flags & ~O_CLOEXEC) != 0)
891 return -EINVAL;
892
893 if (unlikely(oldfd == newfd))
894 return -EINVAL;
895
896 if (newfd >= rlimit(RLIMIT_NOFILE))
897 return -EBADF;
898
899 spin_lock(&files->file_lock);
900 err = expand_files(files, newfd);
901 file = fcheck(oldfd);
902 if (unlikely(!file))
903 goto Ebadf;
904 if (unlikely(err < 0)) {
905 if (err == -EMFILE)
906 goto Ebadf;
907 goto out_unlock;
908 }
909 return do_dup2(files, file, newfd, flags);
910
911Ebadf:
912 err = -EBADF;
913out_unlock:
914 spin_unlock(&files->file_lock);
915 return err;
916}
917
918SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
919{
920 if (unlikely(newfd == oldfd)) {
921 struct files_struct *files = current->files;
922 int retval = oldfd;
923
924 rcu_read_lock();
925 if (!fcheck_files(files, oldfd))
926 retval = -EBADF;
927 rcu_read_unlock();
928 return retval;
929 }
930 return sys_dup3(oldfd, newfd, 0);
931}
932
933SYSCALL_DEFINE1(dup, unsigned int, fildes)
934{
935 int ret = -EBADF;
936 struct file *file = fget_raw(fildes);
937
938 if (file) {
939 ret = get_unused_fd_flags(0);
940 if (ret >= 0)
941 fd_install(ret, file);
942 else
943 fput(file);
944 }
945 return ret;
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