kern_descrip.c revision 1.172.6.5 1 /* $NetBSD: kern_descrip.c,v 1.172.6.5 2009/01/17 13:29:18 mjf Exp $ */
2
3 /*-
4 * Copyright (c) 2008 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 /*
30 * Copyright (c) 1982, 1986, 1989, 1991, 1993
31 * The Regents of the University of California. All rights reserved.
32 * (c) UNIX System Laboratories, Inc.
33 * All or some portions of this file are derived from material licensed
34 * to the University of California by American Telephone and Telegraph
35 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
36 * the permission of UNIX System Laboratories, Inc.
37 *
38 * Redistribution and use in source and binary forms, with or without
39 * modification, are permitted provided that the following conditions
40 * are met:
41 * 1. Redistributions of source code must retain the above copyright
42 * notice, this list of conditions and the following disclaimer.
43 * 2. Redistributions in binary form must reproduce the above copyright
44 * notice, this list of conditions and the following disclaimer in the
45 * documentation and/or other materials provided with the distribution.
46 * 3. Neither the name of the University nor the names of its contributors
47 * may be used to endorse or promote products derived from this software
48 * without specific prior written permission.
49 *
50 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60 * SUCH DAMAGE.
61 *
62 * @(#)kern_descrip.c 8.8 (Berkeley) 2/14/95
63 */
64
65 /*
66 * File descriptor management.
67 */
68
69 #include <sys/cdefs.h>
70 __KERNEL_RCSID(0, "$NetBSD: kern_descrip.c,v 1.172.6.5 2009/01/17 13:29:18 mjf Exp $");
71
72 #include <sys/param.h>
73 #include <sys/systm.h>
74 #include <sys/filedesc.h>
75 #include <sys/kernel.h>
76 #include <sys/proc.h>
77 #include <sys/file.h>
78 #include <sys/socket.h>
79 #include <sys/socketvar.h>
80 #include <sys/stat.h>
81 #include <sys/ioctl.h>
82 #include <sys/fcntl.h>
83 #include <sys/pool.h>
84 #include <sys/unistd.h>
85 #include <sys/resourcevar.h>
86 #include <sys/conf.h>
87 #include <sys/event.h>
88 #include <sys/kauth.h>
89 #include <sys/atomic.h>
90 #include <sys/syscallargs.h>
91 #include <sys/cpu.h>
92 #include <sys/kmem.h>
93 #include <sys/vnode.h>
94
95 static int file_ctor(void *, void *, int);
96 static void file_dtor(void *, void *);
97 static int fdfile_ctor(void *, void *, int);
98 static void fdfile_dtor(void *, void *);
99 static int filedesc_ctor(void *, void *, int);
100 static void filedesc_dtor(void *, void *);
101 static int filedescopen(dev_t, int, int, lwp_t *);
102
103 kmutex_t filelist_lock; /* lock on filehead */
104 struct filelist filehead; /* head of list of open files */
105 u_int nfiles; /* actual number of open files */
106
107 static pool_cache_t filedesc_cache;
108 static pool_cache_t file_cache;
109 static pool_cache_t fdfile_cache;
110
111 const struct cdevsw filedesc_cdevsw = {
112 filedescopen, noclose, noread, nowrite, noioctl,
113 nostop, notty, nopoll, nommap, nokqfilter, D_OTHER | D_MPSAFE,
114 };
115
116 /* For ease of reading. */
117 __strong_alias(fd_putvnode,fd_putfile)
118 __strong_alias(fd_putsock,fd_putfile)
119
120 /*
121 * Initialize the descriptor system.
122 */
123 void
124 fd_sys_init(void)
125 {
126
127 mutex_init(&filelist_lock, MUTEX_DEFAULT, IPL_NONE);
128
129 file_cache = pool_cache_init(sizeof(file_t), coherency_unit, 0,
130 0, "file", NULL, IPL_NONE, file_ctor, file_dtor, NULL);
131 KASSERT(file_cache != NULL);
132
133 fdfile_cache = pool_cache_init(sizeof(fdfile_t), coherency_unit, 0,
134 PR_LARGECACHE, "fdfile", NULL, IPL_NONE, fdfile_ctor, fdfile_dtor,
135 NULL);
136 KASSERT(fdfile_cache != NULL);
137
138 filedesc_cache = pool_cache_init(sizeof(filedesc_t), coherency_unit,
139 0, 0, "filedesc", NULL, IPL_NONE, filedesc_ctor, filedesc_dtor,
140 NULL);
141 KASSERT(filedesc_cache != NULL);
142 }
143
144 static int
145 fd_next_zero(filedesc_t *fdp, uint32_t *bitmap, int want, u_int bits)
146 {
147 int i, off, maxoff;
148 uint32_t sub;
149
150 KASSERT(mutex_owned(&fdp->fd_lock));
151
152 if (want > bits)
153 return -1;
154
155 off = want >> NDENTRYSHIFT;
156 i = want & NDENTRYMASK;
157 if (i) {
158 sub = bitmap[off] | ((u_int)~0 >> (NDENTRIES - i));
159 if (sub != ~0)
160 goto found;
161 off++;
162 }
163
164 maxoff = NDLOSLOTS(bits);
165 while (off < maxoff) {
166 if ((sub = bitmap[off]) != ~0)
167 goto found;
168 off++;
169 }
170
171 return (-1);
172
173 found:
174 return (off << NDENTRYSHIFT) + ffs(~sub) - 1;
175 }
176
177 static int
178 fd_last_set(filedesc_t *fd, int last)
179 {
180 int off, i;
181 fdfile_t **ofiles = fd->fd_ofiles;
182 uint32_t *bitmap = fd->fd_lomap;
183
184 KASSERT(mutex_owned(&fd->fd_lock));
185
186 off = (last - 1) >> NDENTRYSHIFT;
187
188 while (off >= 0 && !bitmap[off])
189 off--;
190
191 if (off < 0)
192 return (-1);
193
194 i = ((off + 1) << NDENTRYSHIFT) - 1;
195 if (i >= last)
196 i = last - 1;
197
198 /* XXX should use bitmap */
199 /* XXXAD does not work for fd_copy() */
200 while (i > 0 && (ofiles[i] == NULL || !ofiles[i]->ff_allocated))
201 i--;
202
203 return (i);
204 }
205
206 void
207 fd_used(filedesc_t *fdp, unsigned fd)
208 {
209 u_int off = fd >> NDENTRYSHIFT;
210 fdfile_t *ff;
211
212 ff = fdp->fd_ofiles[fd];
213
214 KASSERT(mutex_owned(&fdp->fd_lock));
215 KASSERT((fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) == 0);
216 KASSERT(ff != NULL);
217 KASSERT(ff->ff_file == NULL);
218 KASSERT(!ff->ff_allocated);
219
220 ff->ff_allocated = 1;
221 fdp->fd_lomap[off] |= 1 << (fd & NDENTRYMASK);
222 if (fdp->fd_lomap[off] == ~0) {
223 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] &
224 (1 << (off & NDENTRYMASK))) == 0);
225 fdp->fd_himap[off >> NDENTRYSHIFT] |= 1 << (off & NDENTRYMASK);
226 }
227
228 if ((int)fd > fdp->fd_lastfile) {
229 fdp->fd_lastfile = fd;
230 }
231
232 if (fd >= NDFDFILE) {
233 fdp->fd_nused++;
234 } else {
235 KASSERT(ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
236 }
237 }
238
239 void
240 fd_unused(filedesc_t *fdp, unsigned fd)
241 {
242 u_int off = fd >> NDENTRYSHIFT;
243 fdfile_t *ff;
244
245 ff = fdp->fd_ofiles[fd];
246
247 /*
248 * Don't assert the lock is held here, as we may be copying
249 * the table during exec() and it is not needed there.
250 * procfs and sysctl are locked out by proc::p_reflock.
251 *
252 * KASSERT(mutex_owned(&fdp->fd_lock));
253 */
254 KASSERT(ff != NULL);
255 KASSERT(ff->ff_file == NULL);
256 KASSERT(ff->ff_allocated);
257
258 if (fd < fdp->fd_freefile) {
259 fdp->fd_freefile = fd;
260 }
261
262 if (fdp->fd_lomap[off] == ~0) {
263 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] &
264 (1 << (off & NDENTRYMASK))) != 0);
265 fdp->fd_himap[off >> NDENTRYSHIFT] &=
266 ~(1 << (off & NDENTRYMASK));
267 }
268 KASSERT((fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) != 0);
269 fdp->fd_lomap[off] &= ~(1 << (fd & NDENTRYMASK));
270 ff->ff_allocated = 0;
271
272 KASSERT(fd <= fdp->fd_lastfile);
273 if (fd == fdp->fd_lastfile) {
274 fdp->fd_lastfile = fd_last_set(fdp, fd);
275 }
276
277 if (fd >= NDFDFILE) {
278 KASSERT(fdp->fd_nused > 0);
279 fdp->fd_nused--;
280 } else {
281 KASSERT(ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
282 }
283 }
284
285 /*
286 * Custom version of fd_unused() for fd_copy(), where the descriptor
287 * table is not yet fully initialized.
288 */
289 static inline void
290 fd_zap(filedesc_t *fdp, unsigned fd)
291 {
292 u_int off = fd >> NDENTRYSHIFT;
293
294 if (fd < fdp->fd_freefile) {
295 fdp->fd_freefile = fd;
296 }
297
298 if (fdp->fd_lomap[off] == ~0) {
299 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] &
300 (1 << (off & NDENTRYMASK))) != 0);
301 fdp->fd_himap[off >> NDENTRYSHIFT] &=
302 ~(1 << (off & NDENTRYMASK));
303 }
304 KASSERT((fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) != 0);
305 fdp->fd_lomap[off] &= ~(1 << (fd & NDENTRYMASK));
306 }
307
308 bool
309 fd_isused(filedesc_t *fdp, unsigned fd)
310 {
311 u_int off = fd >> NDENTRYSHIFT;
312
313 KASSERT(fd < fdp->fd_nfiles);
314
315 return (fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) != 0;
316 }
317
318 /*
319 * Look up the file structure corresponding to a file descriptor
320 * and return the file, holding a reference on the descriptor.
321 */
322 inline file_t *
323 fd_getfile(unsigned fd)
324 {
325 filedesc_t *fdp;
326 fdfile_t *ff;
327 file_t *fp;
328
329 fdp = curlwp->l_fd;
330
331 /*
332 * Look up the fdfile structure representing this descriptor.
333 * Ensure that we see fd_nfiles before fd_ofiles since we
334 * are doing this unlocked. See fd_tryexpand().
335 */
336 if (__predict_false(fd >= fdp->fd_nfiles)) {
337 return NULL;
338 }
339 membar_consumer();
340 ff = fdp->fd_ofiles[fd];
341 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
342 if (__predict_false(ff == NULL)) {
343 return NULL;
344 }
345
346 /*
347 * Now get a reference to the descriptor. Issue a memory
348 * barrier to ensure that we acquire the file pointer _after_
349 * adding a reference. If no memory barrier, we could fetch
350 * a stale pointer.
351 */
352 atomic_inc_uint(&ff->ff_refcnt);
353 #ifndef __HAVE_ATOMIC_AS_MEMBAR
354 membar_enter();
355 #endif
356
357 /*
358 * If the file is not open or is being closed then put the
359 * reference back.
360 */
361 fp = ff->ff_file;
362 if (__predict_true(fp != NULL)) {
363 return fp;
364 }
365 fd_putfile(fd);
366 return NULL;
367 }
368
369 /*
370 * Release a reference to a file descriptor acquired with fd_getfile().
371 */
372 void
373 fd_putfile(unsigned fd)
374 {
375 filedesc_t *fdp;
376 fdfile_t *ff;
377 u_int u, v;
378
379 fdp = curlwp->l_fd;
380 ff = fdp->fd_ofiles[fd];
381
382 KASSERT(fd < fdp->fd_nfiles);
383 KASSERT(ff != NULL);
384 KASSERT((ff->ff_refcnt & FR_MASK) > 0);
385 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
386
387 /*
388 * Ensure that any use of the file is complete and globally
389 * visible before dropping the final reference. If no membar,
390 * the current CPU could still access memory associated with
391 * the file after it has been freed or recycled by another
392 * CPU.
393 */
394 #ifndef __HAVE_ATOMIC_AS_MEMBAR
395 membar_exit();
396 #endif
397
398 /*
399 * Be optimistic and start out with the assumption that no other
400 * threads are trying to close the descriptor. If the CAS fails,
401 * we lost a race and/or it's being closed.
402 */
403 for (u = ff->ff_refcnt & FR_MASK;; u = v) {
404 v = atomic_cas_uint(&ff->ff_refcnt, u, u - 1);
405 if (__predict_true(u == v)) {
406 return;
407 }
408 if (__predict_false((v & FR_CLOSING) != 0)) {
409 break;
410 }
411 }
412
413 /* Another thread is waiting to close the file: join it. */
414 (void)fd_close(fd);
415 }
416
417 /*
418 * Convenience wrapper around fd_getfile() that returns reference
419 * to a vnode.
420 */
421 int
422 fd_getvnode(unsigned fd, file_t **fpp)
423 {
424 vnode_t *vp;
425 file_t *fp;
426
427 fp = fd_getfile(fd);
428 if (__predict_false(fp == NULL)) {
429 return EBADF;
430 }
431 if (__predict_false(fp->f_type != DTYPE_VNODE)) {
432 fd_putfile(fd);
433 return EINVAL;
434 }
435 vp = fp->f_data;
436 if (__predict_false(vp->v_type == VBAD)) {
437 /* XXX Is this case really necessary? */
438 fd_putfile(fd);
439 return EBADF;
440 }
441 *fpp = fp;
442 return 0;
443 }
444
445 /*
446 * Convenience wrapper around fd_getfile() that returns reference
447 * to a socket.
448 */
449 int
450 fd_getsock(unsigned fd, struct socket **sop)
451 {
452 file_t *fp;
453
454 fp = fd_getfile(fd);
455 if (__predict_false(fp == NULL)) {
456 return EBADF;
457 }
458 if (__predict_false(fp->f_type != DTYPE_SOCKET)) {
459 fd_putfile(fd);
460 return ENOTSOCK;
461 }
462 *sop = fp->f_data;
463 return 0;
464 }
465
466 /*
467 * Look up the file structure corresponding to a file descriptor
468 * and return it with a reference held on the file, not the
469 * descriptor.
470 *
471 * This is heavyweight and only used when accessing descriptors
472 * from a foreign process. The caller must ensure that `p' does
473 * not exit or fork across this call.
474 *
475 * To release the file (not descriptor) reference, use closef().
476 */
477 file_t *
478 fd_getfile2(proc_t *p, unsigned fd)
479 {
480 filedesc_t *fdp;
481 fdfile_t *ff;
482 file_t *fp;
483
484 fdp = p->p_fd;
485 mutex_enter(&fdp->fd_lock);
486 if (fd > fdp->fd_nfiles) {
487 mutex_exit(&fdp->fd_lock);
488 return NULL;
489 }
490 if ((ff = fdp->fd_ofiles[fd]) == NULL) {
491 mutex_exit(&fdp->fd_lock);
492 return NULL;
493 }
494 mutex_enter(&ff->ff_lock);
495 if ((fp = ff->ff_file) == NULL) {
496 mutex_exit(&ff->ff_lock);
497 mutex_exit(&fdp->fd_lock);
498 return NULL;
499 }
500 mutex_enter(&fp->f_lock);
501 fp->f_count++;
502 mutex_exit(&fp->f_lock);
503 mutex_exit(&ff->ff_lock);
504 mutex_exit(&fdp->fd_lock);
505
506 return fp;
507 }
508
509 /*
510 * Internal form of close. Must be called with a reference to the
511 * descriptor, and will drop the reference. When all descriptor
512 * references are dropped, releases the descriptor slot and a single
513 * reference to the file structure.
514 */
515 int
516 fd_close(unsigned fd)
517 {
518 struct flock lf;
519 filedesc_t *fdp;
520 fdfile_t *ff;
521 file_t *fp;
522 proc_t *p;
523 lwp_t *l;
524
525 l = curlwp;
526 p = l->l_proc;
527 fdp = l->l_fd;
528 ff = fdp->fd_ofiles[fd];
529
530 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
531
532 mutex_enter(&ff->ff_lock);
533 KASSERT((ff->ff_refcnt & FR_MASK) > 0);
534 if (ff->ff_file == NULL) {
535 /*
536 * Another user of the file is already closing, and is
537 * waiting for other users of the file to drain. Release
538 * our reference, and wake up the closer.
539 */
540 atomic_dec_uint(&ff->ff_refcnt);
541 cv_broadcast(&ff->ff_closing);
542 mutex_exit(&ff->ff_lock);
543
544 /*
545 * An application error, so pretend that the descriptor
546 * was already closed. We can't safely wait for it to
547 * be closed without potentially deadlocking.
548 */
549 return (EBADF);
550 }
551 KASSERT((ff->ff_refcnt & FR_CLOSING) == 0);
552
553 /*
554 * There may be multiple users of this file within the process.
555 * Notify existing and new users that the file is closing. This
556 * will prevent them from adding additional uses to this file
557 * while we are closing it.
558 */
559 fp = ff->ff_file;
560 ff->ff_file = NULL;
561 ff->ff_exclose = false;
562
563 /*
564 * We expect the caller to hold a descriptor reference - drop it.
565 * The reference count may increase beyond zero at this point due
566 * to an erroneous descriptor reference by an application, but
567 * fd_getfile() will notice that the file is being closed and drop
568 * the reference again.
569 */
570 #ifndef __HAVE_ATOMIC_AS_MEMBAR
571 membar_producer();
572 #endif
573 if (__predict_false(atomic_dec_uint_nv(&ff->ff_refcnt) != 0)) {
574 /*
575 * Wait for other references to drain. This is typically
576 * an application error - the descriptor is being closed
577 * while still in use.
578 *
579 */
580 atomic_or_uint(&ff->ff_refcnt, FR_CLOSING);
581 /*
582 * Remove any knotes attached to the file. A knote
583 * attached to the descriptor can hold references on it.
584 */
585 if (!SLIST_EMPTY(&ff->ff_knlist)) {
586 mutex_exit(&ff->ff_lock);
587 knote_fdclose(fd);
588 mutex_enter(&ff->ff_lock);
589 }
590 /*
591 * We need to see the count drop to zero at least once,
592 * in order to ensure that all pre-existing references
593 * have been drained. New references past this point are
594 * of no interest.
595 */
596 while ((ff->ff_refcnt & FR_MASK) != 0) {
597 cv_wait(&ff->ff_closing, &ff->ff_lock);
598 }
599 atomic_and_uint(&ff->ff_refcnt, ~FR_CLOSING);
600 } else {
601 /* If no references, there must be no knotes. */
602 KASSERT(SLIST_EMPTY(&ff->ff_knlist));
603 }
604 mutex_exit(&ff->ff_lock);
605
606 /*
607 * POSIX record locking dictates that any close releases ALL
608 * locks owned by this process. This is handled by setting
609 * a flag in the unlock to free ONLY locks obeying POSIX
610 * semantics, and not to free BSD-style file locks.
611 * If the descriptor was in a message, POSIX-style locks
612 * aren't passed with the descriptor.
613 */
614 if ((p->p_flag & PK_ADVLOCK) != 0 && fp->f_type == DTYPE_VNODE) {
615 lf.l_whence = SEEK_SET;
616 lf.l_start = 0;
617 lf.l_len = 0;
618 lf.l_type = F_UNLCK;
619 (void)VOP_ADVLOCK(fp->f_data, p, F_UNLCK, &lf, F_POSIX);
620 }
621
622
623 /* Free descriptor slot. */
624 mutex_enter(&fdp->fd_lock);
625 fd_unused(fdp, fd);
626 mutex_exit(&fdp->fd_lock);
627
628 /* Now drop reference to the file itself. */
629 return closef(fp);
630 }
631
632 /*
633 * Duplicate a file descriptor.
634 */
635 int
636 fd_dup(file_t *fp, int minfd, int *newp, bool exclose)
637 {
638 proc_t *p;
639 int error;
640
641 p = curproc;
642
643 while ((error = fd_alloc(p, minfd, newp)) != 0) {
644 if (error != ENOSPC) {
645 return error;
646 }
647 fd_tryexpand(p);
648 }
649
650 curlwp->l_fd->fd_ofiles[*newp]->ff_exclose = exclose;
651 fd_affix(p, fp, *newp);
652 return 0;
653 }
654
655 /*
656 * dup2 operation.
657 */
658 int
659 fd_dup2(file_t *fp, unsigned new)
660 {
661 filedesc_t *fdp;
662 fdfile_t *ff;
663
664 fdp = curlwp->l_fd;
665
666 /*
667 * Ensure there are enough slots in the descriptor table,
668 * and allocate an fdfile_t up front in case we need it.
669 */
670 while (new >= fdp->fd_nfiles) {
671 fd_tryexpand(curproc);
672 }
673 ff = pool_cache_get(fdfile_cache, PR_WAITOK);
674
675 /*
676 * If there is already a file open, close it. If the file is
677 * half open, wait for it to be constructed before closing it.
678 * XXX Potential for deadlock here?
679 */
680 mutex_enter(&fdp->fd_lock);
681 while (fd_isused(fdp, new)) {
682 mutex_exit(&fdp->fd_lock);
683 if (fd_getfile(new) != NULL) {
684 (void)fd_close(new);
685 } else {
686 /* XXX Crummy, but unlikely to happen. */
687 kpause("dup2", false, 1, NULL);
688 }
689 mutex_enter(&fdp->fd_lock);
690 }
691 if (fdp->fd_ofiles[new] == NULL) {
692 KASSERT(new >= NDFDFILE);
693 fdp->fd_ofiles[new] = ff;
694 ff = NULL;
695 }
696 fd_used(fdp, new);
697 mutex_exit(&fdp->fd_lock);
698
699 /* Slot is now allocated. Insert copy of the file. */
700 fd_affix(curproc, fp, new);
701 if (ff != NULL) {
702 pool_cache_put(fdfile_cache, ff);
703 }
704 return 0;
705 }
706
707 /*
708 * Drop reference to a file structure.
709 */
710 int
711 closef(file_t *fp)
712 {
713 struct flock lf;
714 int error;
715
716 /*
717 * Drop reference. If referenced elsewhere it's still open
718 * and we have nothing more to do.
719 */
720 mutex_enter(&fp->f_lock);
721 KASSERT(fp->f_count > 0);
722 if (--fp->f_count > 0) {
723 mutex_exit(&fp->f_lock);
724 return 0;
725 }
726 KASSERT(fp->f_count == 0);
727 mutex_exit(&fp->f_lock);
728
729 /* We held the last reference - release locks, close and free. */
730 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) {
731 lf.l_whence = SEEK_SET;
732 lf.l_start = 0;
733 lf.l_len = 0;
734 lf.l_type = F_UNLCK;
735 (void)VOP_ADVLOCK(fp->f_data, fp, F_UNLCK, &lf, F_FLOCK);
736 }
737 if (fp->f_ops != NULL) {
738 error = (*fp->f_ops->fo_close)(fp);
739 } else {
740 error = 0;
741 }
742 ffree(fp);
743
744 return error;
745 }
746
747 /*
748 * Allocate a file descriptor for the process.
749 */
750 int
751 fd_alloc(proc_t *p, int want, int *result)
752 {
753 filedesc_t *fdp;
754 int i, lim, last, error;
755 u_int off, new;
756 fdfile_t *ff;
757
758 KASSERT(p == curproc || p == &proc0);
759
760 fdp = p->p_fd;
761 ff = pool_cache_get(fdfile_cache, PR_WAITOK);
762 KASSERT(ff->ff_refcnt == 0);
763 KASSERT(ff->ff_file == NULL);
764
765 /*
766 * Search for a free descriptor starting at the higher
767 * of want or fd_freefile.
768 */
769 mutex_enter(&fdp->fd_lock);
770 KASSERT(fdp->fd_ofiles[0] == (fdfile_t *)fdp->fd_dfdfile[0]);
771 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles);
772 last = min(fdp->fd_nfiles, lim);
773 for (;;) {
774 if ((i = want) < fdp->fd_freefile)
775 i = fdp->fd_freefile;
776 off = i >> NDENTRYSHIFT;
777 new = fd_next_zero(fdp, fdp->fd_himap, off,
778 (last + NDENTRIES - 1) >> NDENTRYSHIFT);
779 if (new == -1)
780 break;
781 i = fd_next_zero(fdp, &fdp->fd_lomap[new],
782 new > off ? 0 : i & NDENTRYMASK, NDENTRIES);
783 if (i == -1) {
784 /*
785 * Free file descriptor in this block was
786 * below want, try again with higher want.
787 */
788 want = (new + 1) << NDENTRYSHIFT;
789 continue;
790 }
791 i += (new << NDENTRYSHIFT);
792 if (i >= last) {
793 break;
794 }
795 if (fdp->fd_ofiles[i] == NULL) {
796 KASSERT(i >= NDFDFILE);
797 fdp->fd_ofiles[i] = ff;
798 } else {
799 pool_cache_put(fdfile_cache, ff);
800 }
801 KASSERT(fdp->fd_ofiles[i]->ff_file == NULL);
802 fd_used(fdp, i);
803 if (want <= fdp->fd_freefile) {
804 fdp->fd_freefile = i;
805 }
806 *result = i;
807 mutex_exit(&fdp->fd_lock);
808 KASSERT(i >= NDFDFILE ||
809 fdp->fd_ofiles[i] == (fdfile_t *)fdp->fd_dfdfile[i]);
810 return 0;
811 }
812
813 /* No space in current array. Let the caller expand and retry. */
814 error = (fdp->fd_nfiles >= lim) ? EMFILE : ENOSPC;
815 mutex_exit(&fdp->fd_lock);
816 pool_cache_put(fdfile_cache, ff);
817 return error;
818 }
819
820 /*
821 * Allocate memory for the open files array.
822 */
823 static fdfile_t **
824 fd_ofile_alloc(int n)
825 {
826 uintptr_t *ptr, sz;
827
828 KASSERT(n > NDFILE);
829
830 sz = (n + 2) * sizeof(uintptr_t);
831 ptr = kmem_alloc((size_t)sz, KM_SLEEP);
832 ptr[1] = sz;
833
834 return (fdfile_t **)(ptr + 2);
835 }
836
837 /*
838 * Free an open files array.
839 */
840 static void
841 fd_ofile_free(int n, fdfile_t **of)
842 {
843 uintptr_t *ptr, sz;
844
845 KASSERT(n > NDFILE);
846
847 sz = (n + 2) * sizeof(uintptr_t);
848 ptr = (uintptr_t *)of - 2;
849 KASSERT(ptr[1] == sz);
850 kmem_free(ptr, sz);
851 }
852
853 /*
854 * Allocate descriptor bitmap.
855 */
856 static void
857 fd_map_alloc(int n, uint32_t **lo, uint32_t **hi)
858 {
859 uint8_t *ptr;
860 size_t szlo, szhi;
861
862 KASSERT(n > NDENTRIES);
863
864 szlo = NDLOSLOTS(n) * sizeof(uint32_t);
865 szhi = NDHISLOTS(n) * sizeof(uint32_t);
866 ptr = kmem_alloc(szlo + szhi, KM_SLEEP);
867 *lo = (uint32_t *)ptr;
868 *hi = (uint32_t *)(ptr + szlo);
869 }
870
871 /*
872 * Free descriptor bitmap.
873 */
874 static void
875 fd_map_free(int n, uint32_t *lo, uint32_t *hi)
876 {
877 size_t szlo, szhi;
878
879 KASSERT(n > NDENTRIES);
880
881 szlo = NDLOSLOTS(n) * sizeof(uint32_t);
882 szhi = NDHISLOTS(n) * sizeof(uint32_t);
883 KASSERT(hi == (uint32_t *)((uint8_t *)lo + szlo));
884 kmem_free(lo, szlo + szhi);
885 }
886
887 /*
888 * Expand a process' descriptor table.
889 */
890 void
891 fd_tryexpand(proc_t *p)
892 {
893 filedesc_t *fdp;
894 int i, numfiles, oldnfiles;
895 fdfile_t **newofile;
896 uint32_t *newhimap, *newlomap;
897
898 KASSERT(p == curproc || p == &proc0);
899
900 fdp = p->p_fd;
901 newhimap = NULL;
902 newlomap = NULL;
903 oldnfiles = fdp->fd_nfiles;
904
905 if (oldnfiles < NDEXTENT)
906 numfiles = NDEXTENT;
907 else
908 numfiles = 2 * oldnfiles;
909
910 newofile = fd_ofile_alloc(numfiles);
911 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) {
912 fd_map_alloc(numfiles, &newlomap, &newhimap);
913 }
914
915 mutex_enter(&fdp->fd_lock);
916 KASSERT(fdp->fd_ofiles[0] == (fdfile_t *)fdp->fd_dfdfile[0]);
917 if (fdp->fd_nfiles != oldnfiles) {
918 /* fdp changed; caller must retry */
919 mutex_exit(&fdp->fd_lock);
920 fd_ofile_free(numfiles, newofile);
921 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) {
922 fd_map_free(numfiles, newlomap, newhimap);
923 }
924 return;
925 }
926
927 /* Copy the existing ofile array and zero the new portion. */
928 i = sizeof(fdfile_t *) * fdp->fd_nfiles;
929 memcpy(newofile, fdp->fd_ofiles, i);
930 memset((uint8_t *)newofile + i, 0, numfiles * sizeof(fdfile_t *) - i);
931
932 /*
933 * Link old ofiles array into list to be discarded. We defer
934 * freeing until process exit if the descriptor table is visble
935 * to other threads.
936 */
937 if (oldnfiles > NDFILE) {
938 if ((fdp->fd_refcnt | p->p_nlwps) > 1) {
939 fdp->fd_ofiles[-2] = (void *)fdp->fd_discard;
940 fdp->fd_discard = fdp->fd_ofiles - 2;
941 } else {
942 fd_ofile_free(oldnfiles, fdp->fd_ofiles);
943 }
944 }
945
946 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) {
947 i = NDHISLOTS(oldnfiles) * sizeof(uint32_t);
948 memcpy(newhimap, fdp->fd_himap, i);
949 memset((uint8_t *)newhimap + i, 0,
950 NDHISLOTS(numfiles) * sizeof(uint32_t) - i);
951
952 i = NDLOSLOTS(oldnfiles) * sizeof(uint32_t);
953 memcpy(newlomap, fdp->fd_lomap, i);
954 memset((uint8_t *)newlomap + i, 0,
955 NDLOSLOTS(numfiles) * sizeof(uint32_t) - i);
956
957 if (NDHISLOTS(oldnfiles) > NDHISLOTS(NDFILE)) {
958 fd_map_free(oldnfiles, fdp->fd_lomap, fdp->fd_himap);
959 }
960 fdp->fd_himap = newhimap;
961 fdp->fd_lomap = newlomap;
962 }
963
964 /*
965 * All other modifications must become globally visible before
966 * the change to fd_nfiles. See fd_getfile().
967 */
968 fdp->fd_ofiles = newofile;
969 membar_producer();
970 fdp->fd_nfiles = numfiles;
971 mutex_exit(&fdp->fd_lock);
972
973 KASSERT(fdp->fd_ofiles[0] == (fdfile_t *)fdp->fd_dfdfile[0]);
974 }
975
976 /*
977 * Create a new open file structure and allocate a file descriptor
978 * for the current process.
979 */
980 int
981 fd_allocfile(file_t **resultfp, int *resultfd)
982 {
983 file_t *fp;
984 proc_t *p;
985 int error;
986
987 p = curproc;
988
989 while ((error = fd_alloc(p, 0, resultfd)) != 0) {
990 if (error != ENOSPC) {
991 return error;
992 }
993 fd_tryexpand(p);
994 }
995
996 fp = pool_cache_get(file_cache, PR_WAITOK);
997 KASSERT(fp->f_count == 0);
998 fp->f_cred = kauth_cred_get();
999 kauth_cred_hold(fp->f_cred);
1000
1001 if (__predict_false(atomic_inc_uint_nv(&nfiles) >= maxfiles)) {
1002 fd_abort(p, fp, *resultfd);
1003 tablefull("file", "increase kern.maxfiles or MAXFILES");
1004 return ENFILE;
1005 }
1006
1007 fp->f_advice = 0;
1008 fp->f_msgcount = 0;
1009 fp->f_offset = 0;
1010 fp->f_iflags = 0;
1011 *resultfp = fp;
1012
1013 return 0;
1014 }
1015
1016 /*
1017 * Successful creation of a new descriptor: make visible to the process.
1018 */
1019 void
1020 fd_affix(proc_t *p, file_t *fp, unsigned fd)
1021 {
1022 fdfile_t *ff;
1023 filedesc_t *fdp;
1024
1025 KASSERT(p == curproc || p == &proc0);
1026
1027 /* Add a reference to the file structure. */
1028 mutex_enter(&fp->f_lock);
1029 fp->f_count++;
1030 mutex_exit(&fp->f_lock);
1031
1032 /*
1033 * Insert the new file into the descriptor slot.
1034 *
1035 * The memory barriers provided by lock activity in this routine
1036 * ensure that any updates to the file structure become globally
1037 * visible before the file becomes visible to other LWPs in the
1038 * current process.
1039 */
1040 fdp = p->p_fd;
1041 ff = fdp->fd_ofiles[fd];
1042
1043 KASSERT(ff != NULL);
1044 KASSERT(ff->ff_file == NULL);
1045 KASSERT(ff->ff_allocated);
1046 KASSERT(fd_isused(fdp, fd));
1047 KASSERT(fd >= NDFDFILE ||
1048 fdp->fd_ofiles[fd] == (fdfile_t *)fdp->fd_dfdfile[fd]);
1049
1050 /* No need to lock in order to make file initially visible. */
1051 ff->ff_file = fp;
1052 }
1053
1054 /*
1055 * Abort creation of a new descriptor: free descriptor slot and file.
1056 */
1057 void
1058 fd_abort(proc_t *p, file_t *fp, unsigned fd)
1059 {
1060 filedesc_t *fdp;
1061 fdfile_t *ff;
1062
1063 KASSERT(p == curproc || p == &proc0);
1064
1065 fdp = p->p_fd;
1066 ff = fdp->fd_ofiles[fd];
1067
1068 KASSERT(fd >= NDFDFILE ||
1069 fdp->fd_ofiles[fd] == (fdfile_t *)fdp->fd_dfdfile[fd]);
1070
1071 mutex_enter(&fdp->fd_lock);
1072 KASSERT(fd_isused(fdp, fd));
1073 fd_unused(fdp, fd);
1074 mutex_exit(&fdp->fd_lock);
1075
1076 if (fp != NULL) {
1077 ffree(fp);
1078 }
1079 }
1080
1081 /*
1082 * Free a file descriptor.
1083 */
1084 void
1085 ffree(file_t *fp)
1086 {
1087
1088 KASSERT(fp->f_count == 0);
1089
1090 atomic_dec_uint(&nfiles);
1091 kauth_cred_free(fp->f_cred);
1092 pool_cache_put(file_cache, fp);
1093 }
1094
1095 static int
1096 file_ctor(void *arg, void *obj, int flags)
1097 {
1098 file_t *fp = obj;
1099
1100 memset(fp, 0, sizeof(*fp));
1101 mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE);
1102
1103 mutex_enter(&filelist_lock);
1104 LIST_INSERT_HEAD(&filehead, fp, f_list);
1105 mutex_exit(&filelist_lock);
1106
1107 return 0;
1108 }
1109
1110 static void
1111 file_dtor(void *arg, void *obj)
1112 {
1113 file_t *fp = obj;
1114
1115 mutex_enter(&filelist_lock);
1116 LIST_REMOVE(fp, f_list);
1117 mutex_exit(&filelist_lock);
1118
1119 mutex_destroy(&fp->f_lock);
1120 }
1121
1122 static int
1123 fdfile_ctor(void *arg, void *obj, int flags)
1124 {
1125 fdfile_t *ff = obj;
1126
1127 memset(ff, 0, sizeof(*ff));
1128 mutex_init(&ff->ff_lock, MUTEX_DEFAULT, IPL_NONE);
1129 cv_init(&ff->ff_closing, "fdclose");
1130
1131 return 0;
1132 }
1133
1134 static void
1135 fdfile_dtor(void *arg, void *obj)
1136 {
1137 fdfile_t *ff = obj;
1138
1139 mutex_destroy(&ff->ff_lock);
1140 cv_destroy(&ff->ff_closing);
1141 }
1142
1143 file_t *
1144 fgetdummy(void)
1145 {
1146 file_t *fp;
1147
1148 fp = kmem_alloc(sizeof(*fp), KM_SLEEP);
1149 if (fp != NULL) {
1150 memset(fp, 0, sizeof(*fp));
1151 mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE);
1152 }
1153 return fp;
1154 }
1155
1156 void
1157 fputdummy(file_t *fp)
1158 {
1159
1160 mutex_destroy(&fp->f_lock);
1161 kmem_free(fp, sizeof(*fp));
1162 }
1163
1164 /*
1165 * Create an initial filedesc structure.
1166 */
1167 filedesc_t *
1168 fd_init(filedesc_t *fdp)
1169 {
1170 unsigned fd;
1171
1172 if (fdp == NULL) {
1173 fdp = pool_cache_get(filedesc_cache, PR_WAITOK);
1174 } else {
1175 filedesc_ctor(NULL, fdp, PR_WAITOK);
1176 }
1177
1178 fdp->fd_refcnt = 1;
1179 fdp->fd_ofiles = fdp->fd_dfiles;
1180 fdp->fd_nfiles = NDFILE;
1181 fdp->fd_himap = fdp->fd_dhimap;
1182 fdp->fd_lomap = fdp->fd_dlomap;
1183 KASSERT(fdp->fd_lastfile == -1);
1184 KASSERT(fdp->fd_lastkqfile == -1);
1185 KASSERT(fdp->fd_knhash == NULL);
1186
1187 memset(&fdp->fd_startzero, 0, sizeof(*fdp) -
1188 offsetof(filedesc_t, fd_startzero));
1189 for (fd = 0; fd < NDFDFILE; fd++) {
1190 fdp->fd_ofiles[fd] = (fdfile_t *)fdp->fd_dfdfile[fd];
1191 }
1192
1193 return fdp;
1194 }
1195
1196 /*
1197 * Initialize a file descriptor table.
1198 */
1199 static int
1200 filedesc_ctor(void *arg, void *obj, int flag)
1201 {
1202 filedesc_t *fdp = obj;
1203 int i;
1204
1205 memset(fdp, 0, sizeof(*fdp));
1206 mutex_init(&fdp->fd_lock, MUTEX_DEFAULT, IPL_NONE);
1207 fdp->fd_lastfile = -1;
1208 fdp->fd_lastkqfile = -1;
1209
1210 CTASSERT(sizeof(fdp->fd_dfdfile[0]) >= sizeof(fdfile_t));
1211 for (i = 0; i < NDFDFILE; i++) {
1212 fdfile_ctor(NULL, fdp->fd_dfdfile[i], PR_WAITOK);
1213 }
1214
1215 return 0;
1216 }
1217
1218 static void
1219 filedesc_dtor(void *arg, void *obj)
1220 {
1221 filedesc_t *fdp = obj;
1222 int i;
1223
1224 for (i = 0; i < NDFDFILE; i++) {
1225 fdfile_dtor(NULL, fdp->fd_dfdfile[i]);
1226 }
1227
1228 mutex_destroy(&fdp->fd_lock);
1229 }
1230
1231 /*
1232 * Make p2 share p1's filedesc structure.
1233 */
1234 void
1235 fd_share(struct proc *p2)
1236 {
1237 filedesc_t *fdp;
1238
1239 fdp = curlwp->l_fd;
1240 p2->p_fd = fdp;
1241 atomic_inc_uint(&fdp->fd_refcnt);
1242 }
1243
1244 /*
1245 * Copy a filedesc structure.
1246 */
1247 filedesc_t *
1248 fd_copy(void)
1249 {
1250 filedesc_t *newfdp, *fdp;
1251 fdfile_t *ff, *fflist, **ffp, **nffp, *ff2;
1252 int i, nused, numfiles, lastfile, j, newlast;
1253 file_t *fp;
1254
1255 fdp = curproc->p_fd;
1256 newfdp = pool_cache_get(filedesc_cache, PR_WAITOK);
1257 newfdp->fd_refcnt = 1;
1258
1259 KASSERT(newfdp->fd_knhash == NULL);
1260 KASSERT(newfdp->fd_knhashmask == 0);
1261 KASSERT(newfdp->fd_discard == NULL);
1262
1263 for (;;) {
1264 numfiles = fdp->fd_nfiles;
1265 lastfile = fdp->fd_lastfile;
1266
1267 /*
1268 * If the number of open files fits in the internal arrays
1269 * of the open file structure, use them, otherwise allocate
1270 * additional memory for the number of descriptors currently
1271 * in use.
1272 */
1273 if (lastfile < NDFILE) {
1274 i = NDFILE;
1275 newfdp->fd_ofiles = newfdp->fd_dfiles;
1276 } else {
1277 /*
1278 * Compute the smallest multiple of NDEXTENT needed
1279 * for the file descriptors currently in use,
1280 * allowing the table to shrink.
1281 */
1282 i = numfiles;
1283 while (i >= 2 * NDEXTENT && i > lastfile * 2) {
1284 i /= 2;
1285 }
1286 newfdp->fd_ofiles = fd_ofile_alloc(i);
1287 KASSERT(i >= NDFILE);
1288 }
1289 if (NDHISLOTS(i) <= NDHISLOTS(NDFILE)) {
1290 newfdp->fd_himap = newfdp->fd_dhimap;
1291 newfdp->fd_lomap = newfdp->fd_dlomap;
1292 } else {
1293 fd_map_alloc(i, &newfdp->fd_lomap,
1294 &newfdp->fd_himap);
1295 }
1296
1297 /*
1298 * Allocate and string together fdfile structures.
1299 * We abuse fdfile_t::ff_file here, but it will be
1300 * cleared before this routine returns.
1301 */
1302 nused = fdp->fd_nused;
1303 fflist = NULL;
1304 for (j = nused; j != 0; j--) {
1305 ff = pool_cache_get(fdfile_cache, PR_WAITOK);
1306 ff->ff_file = (void *)fflist;
1307 fflist = ff;
1308 }
1309
1310 mutex_enter(&fdp->fd_lock);
1311 if (numfiles == fdp->fd_nfiles && nused == fdp->fd_nused &&
1312 lastfile == fdp->fd_lastfile) {
1313 break;
1314 }
1315 mutex_exit(&fdp->fd_lock);
1316 if (i >= NDFILE) {
1317 fd_ofile_free(i, newfdp->fd_ofiles);
1318 }
1319 if (NDHISLOTS(i) > NDHISLOTS(NDFILE)) {
1320 fd_map_free(i, newfdp->fd_lomap, newfdp->fd_himap);
1321 }
1322 while (fflist != NULL) {
1323 ff = fflist;
1324 fflist = (void *)ff->ff_file;
1325 ff->ff_file = NULL;
1326 pool_cache_put(fdfile_cache, ff);
1327 }
1328 }
1329
1330 newfdp->fd_nfiles = i;
1331 newfdp->fd_freefile = fdp->fd_freefile;
1332 newfdp->fd_exclose = fdp->fd_exclose;
1333
1334 /*
1335 * Clear the entries that will not be copied over.
1336 * Avoid calling memset with 0 size.
1337 */
1338 if (lastfile < (i-1)) {
1339 memset(newfdp->fd_ofiles + lastfile + 1, 0,
1340 (i - lastfile - 1) * sizeof(file_t **));
1341 }
1342 if (i < NDENTRIES * NDENTRIES) {
1343 i = NDENTRIES * NDENTRIES; /* size of inlined bitmaps */
1344 }
1345 memcpy(newfdp->fd_himap, fdp->fd_himap, NDHISLOTS(i)*sizeof(uint32_t));
1346 memcpy(newfdp->fd_lomap, fdp->fd_lomap, NDLOSLOTS(i)*sizeof(uint32_t));
1347
1348 ffp = fdp->fd_ofiles;
1349 nffp = newfdp->fd_ofiles;
1350 j = imax(lastfile, (NDFDFILE - 1));
1351 newlast = -1;
1352 KASSERT(j < fdp->fd_nfiles);
1353 for (i = 0; i <= j; i++, ffp++, *nffp++ = ff2) {
1354 ff = *ffp;
1355 /* Install built-in fdfiles even if unused here. */
1356 if (i < NDFDFILE) {
1357 ff2 = (fdfile_t *)newfdp->fd_dfdfile[i];
1358 } else {
1359 ff2 = NULL;
1360 }
1361 /* Determine if descriptor is active in parent. */
1362 if (ff == NULL || !fd_isused(fdp, i)) {
1363 KASSERT(ff != NULL || i >= NDFDFILE);
1364 continue;
1365 }
1366 mutex_enter(&ff->ff_lock);
1367 fp = ff->ff_file;
1368 if (fp == NULL) {
1369 /* Descriptor is half-open: free slot. */
1370 fd_zap(newfdp, i);
1371 mutex_exit(&ff->ff_lock);
1372 continue;
1373 }
1374 if (fp->f_type == DTYPE_KQUEUE) {
1375 /* kqueue descriptors cannot be copied. */
1376 fd_zap(newfdp, i);
1377 mutex_exit(&ff->ff_lock);
1378 continue;
1379 }
1380 /* It's active: add a reference to the file. */
1381 mutex_enter(&fp->f_lock);
1382 fp->f_count++;
1383 mutex_exit(&fp->f_lock);
1384 /* Consume one fdfile_t to represent it. */
1385 if (i >= NDFDFILE) {
1386 ff2 = fflist;
1387 fflist = (void *)ff2->ff_file;
1388 }
1389 ff2->ff_file = fp;
1390 ff2->ff_exclose = ff->ff_exclose;
1391 ff2->ff_allocated = true;
1392 mutex_exit(&ff->ff_lock);
1393 if (i > newlast) {
1394 newlast = i;
1395 }
1396 }
1397 mutex_exit(&fdp->fd_lock);
1398
1399 /* Discard unused fdfile_t structures. */
1400 while (__predict_false(fflist != NULL)) {
1401 ff = fflist;
1402 fflist = (void *)ff->ff_file;
1403 ff->ff_file = NULL;
1404 pool_cache_put(fdfile_cache, ff);
1405 nused--;
1406 }
1407 KASSERT(nused >= 0);
1408 KASSERT(newfdp->fd_ofiles[0] == (fdfile_t *)newfdp->fd_dfdfile[0]);
1409
1410 newfdp->fd_nused = nused;
1411 newfdp->fd_lastfile = newlast;
1412
1413 return (newfdp);
1414 }
1415
1416 /*
1417 * Release a filedesc structure.
1418 */
1419 void
1420 fd_free(void)
1421 {
1422 filedesc_t *fdp;
1423 fdfile_t *ff;
1424 file_t *fp;
1425 int fd, lastfd;
1426 void **discard;
1427
1428 fdp = curlwp->l_fd;
1429
1430 KASSERT(fdp->fd_ofiles[0] == (fdfile_t *)fdp->fd_dfdfile[0]);
1431
1432 if (atomic_dec_uint_nv(&fdp->fd_refcnt) > 0)
1433 return;
1434
1435 /*
1436 * Close any files that the process holds open.
1437 */
1438 for (fd = 0, lastfd = fdp->fd_nfiles - 1; fd <= lastfd; fd++) {
1439 ff = fdp->fd_ofiles[fd];
1440 KASSERT(fd >= NDFDFILE ||
1441 ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
1442 if ((ff = fdp->fd_ofiles[fd]) == NULL)
1443 continue;
1444 if ((fp = ff->ff_file) != NULL) {
1445 /*
1446 * Must use fd_close() here as kqueue holds
1447 * long term references to descriptors.
1448 */
1449 ff->ff_refcnt++;
1450 fd_close(fd);
1451 }
1452 KASSERT(ff->ff_refcnt == 0);
1453 KASSERT(ff->ff_file == NULL);
1454 KASSERT(!ff->ff_exclose);
1455 KASSERT(!ff->ff_allocated);
1456 if (fd >= NDFDFILE) {
1457 pool_cache_put(fdfile_cache, ff);
1458 }
1459 }
1460
1461 /*
1462 * Clean out the descriptor table for the next user and return
1463 * to the cache.
1464 */
1465 while ((discard = fdp->fd_discard) != NULL) {
1466 fdp->fd_discard = discard[0];
1467 kmem_free(discard, (uintptr_t)discard[1]);
1468 }
1469 if (NDHISLOTS(fdp->fd_nfiles) > NDHISLOTS(NDFILE)) {
1470 KASSERT(fdp->fd_himap != fdp->fd_dhimap);
1471 KASSERT(fdp->fd_lomap != fdp->fd_dlomap);
1472 fd_map_free(fdp->fd_nfiles, fdp->fd_lomap, fdp->fd_himap);
1473 }
1474 if (fdp->fd_nfiles > NDFILE) {
1475 KASSERT(fdp->fd_ofiles != fdp->fd_dfiles);
1476 fd_ofile_free(fdp->fd_nfiles, fdp->fd_ofiles);
1477 }
1478 if (fdp->fd_knhash != NULL) {
1479 hashdone(fdp->fd_knhash, HASH_LIST, fdp->fd_knhashmask);
1480 fdp->fd_knhash = NULL;
1481 fdp->fd_knhashmask = 0;
1482 } else {
1483 KASSERT(fdp->fd_knhashmask == 0);
1484 }
1485 fdp->fd_lastkqfile = -1;
1486 pool_cache_put(filedesc_cache, fdp);
1487 }
1488
1489 /*
1490 * File Descriptor pseudo-device driver (/dev/fd/).
1491 *
1492 * Opening minor device N dup()s the file (if any) connected to file
1493 * descriptor N belonging to the calling process. Note that this driver
1494 * consists of only the ``open()'' routine, because all subsequent
1495 * references to this file will be direct to the other driver.
1496 */
1497 static int
1498 filedescopen(dev_t dev, int mode, int type, lwp_t *l)
1499 {
1500
1501 /*
1502 * XXX Kludge: set dupfd to contain the value of the
1503 * the file descriptor being sought for duplication. The error
1504 * return ensures that the vnode for this device will be released
1505 * by vn_open. Open will detect this special error and take the
1506 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
1507 * will simply report the error.
1508 */
1509 l->l_dupfd = minor(dev); /* XXX */
1510 return EDUPFD;
1511 }
1512
1513 /*
1514 * Duplicate the specified descriptor to a free descriptor.
1515 */
1516 int
1517 fd_dupopen(int old, int *new, int mode, int error)
1518 {
1519 filedesc_t *fdp;
1520 fdfile_t *ff;
1521 file_t *fp;
1522
1523 if ((fp = fd_getfile(old)) == NULL) {
1524 return EBADF;
1525 }
1526 fdp = curlwp->l_fd;
1527 ff = fdp->fd_ofiles[old];
1528
1529 /*
1530 * There are two cases of interest here.
1531 *
1532 * For EDUPFD simply dup (dfd) to file descriptor
1533 * (indx) and return.
1534 *
1535 * For EMOVEFD steal away the file structure from (dfd) and
1536 * store it in (indx). (dfd) is effectively closed by
1537 * this operation.
1538 *
1539 * Any other error code is just returned.
1540 */
1541 switch (error) {
1542 case EDUPFD:
1543 /*
1544 * Check that the mode the file is being opened for is a
1545 * subset of the mode of the existing descriptor.
1546 */
1547 if (((mode & (FREAD|FWRITE)) | fp->f_flag) != fp->f_flag) {
1548 error = EACCES;
1549 break;
1550 }
1551
1552 /* Copy it. */
1553 error = fd_dup(fp, 0, new, fdp->fd_ofiles[old]->ff_exclose);
1554 break;
1555
1556 case EMOVEFD:
1557 /* Copy it. */
1558 error = fd_dup(fp, 0, new, fdp->fd_ofiles[old]->ff_exclose);
1559 if (error != 0) {
1560 break;
1561 }
1562
1563 /* Steal away the file pointer from 'old'. */
1564 (void)fd_close(old);
1565 return 0;
1566 }
1567
1568 fd_putfile(old);
1569 return error;
1570 }
1571
1572 /*
1573 * Sets descriptor owner. If the owner is a process, 'pgid'
1574 * is set to positive value, process ID. If the owner is process group,
1575 * 'pgid' is set to -pg_id.
1576 */
1577 int
1578 fsetown(pid_t *pgid, u_long cmd, const void *data)
1579 {
1580 int id = *(const int *)data;
1581 int error;
1582
1583 switch (cmd) {
1584 case TIOCSPGRP:
1585 if (id < 0)
1586 return (EINVAL);
1587 id = -id;
1588 break;
1589 default:
1590 break;
1591 }
1592
1593 if (id > 0 && !pfind(id))
1594 return (ESRCH);
1595 else if (id < 0 && (error = pgid_in_session(curproc, -id)))
1596 return (error);
1597
1598 *pgid = id;
1599 return (0);
1600 }
1601
1602 /*
1603 * Return descriptor owner information. If the value is positive,
1604 * it's process ID. If it's negative, it's process group ID and
1605 * needs the sign removed before use.
1606 */
1607 int
1608 fgetown(pid_t pgid, u_long cmd, void *data)
1609 {
1610
1611 switch (cmd) {
1612 case TIOCGPGRP:
1613 *(int *)data = -pgid;
1614 break;
1615 default:
1616 *(int *)data = pgid;
1617 break;
1618 }
1619 return (0);
1620 }
1621
1622 /*
1623 * Send signal to descriptor owner, either process or process group.
1624 */
1625 void
1626 fownsignal(pid_t pgid, int signo, int code, int band, void *fdescdata)
1627 {
1628 struct proc *p1;
1629 struct pgrp *pgrp;
1630 ksiginfo_t ksi;
1631
1632 KASSERT(!cpu_intr_p());
1633
1634 KSI_INIT(&ksi);
1635 ksi.ksi_signo = signo;
1636 ksi.ksi_code = code;
1637 ksi.ksi_band = band;
1638
1639 mutex_enter(proc_lock);
1640 if (pgid > 0 && (p1 = p_find(pgid, PFIND_LOCKED)))
1641 kpsignal(p1, &ksi, fdescdata);
1642 else if (pgid < 0 && (pgrp = pg_find(-pgid, PFIND_LOCKED)))
1643 kpgsignal(pgrp, &ksi, fdescdata, 0);
1644 mutex_exit(proc_lock);
1645 }
1646
1647 int
1648 fd_clone(file_t *fp, unsigned fd, int flag, const struct fileops *fops,
1649 void *data)
1650 {
1651
1652 fp->f_flag = flag;
1653 fp->f_type = DTYPE_MISC;
1654 fp->f_ops = fops;
1655 fp->f_data = data;
1656 curlwp->l_dupfd = fd;
1657 fd_affix(curproc, fp, fd);
1658
1659 return EMOVEFD;
1660 }
1661
1662 int
1663 fnullop_fcntl(file_t *fp, u_int cmd, void *data)
1664 {
1665
1666 if (cmd == F_SETFL)
1667 return 0;
1668
1669 return EOPNOTSUPP;
1670 }
1671
1672 int
1673 fnullop_poll(file_t *fp, int which)
1674 {
1675
1676 return 0;
1677 }
1678
1679 int
1680 fnullop_kqfilter(file_t *fp, struct knote *kn)
1681 {
1682
1683 return 0;
1684 }
1685
1686 int
1687 fbadop_read(file_t *fp, off_t *offset, struct uio *uio,
1688 kauth_cred_t cred, int flags)
1689 {
1690
1691 return EOPNOTSUPP;
1692 }
1693
1694 int
1695 fbadop_write(file_t *fp, off_t *offset, struct uio *uio,
1696 kauth_cred_t cred, int flags)
1697 {
1698
1699 return EOPNOTSUPP;
1700 }
1701
1702 int
1703 fbadop_ioctl(file_t *fp, u_long com, void *data)
1704 {
1705
1706 return EOPNOTSUPP;
1707 }
1708
1709 int
1710 fbadop_stat(file_t *fp, struct stat *sb)
1711 {
1712
1713 return EOPNOTSUPP;
1714 }
1715
1716 int
1717 fbadop_close(file_t *fp)
1718 {
1719
1720 return EOPNOTSUPP;
1721 }
1722