1 /* $NetBSD: kern_descrip.c,v 1.251 2021/06/29 22:40:53 dholland Exp $ */
2
3 /*-
4 * Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Andrew Doran.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 /*
33 * Copyright (c) 1982, 1986, 1989, 1991, 1993
34 * The Regents of the University of California. All rights reserved.
35 * (c) UNIX System Laboratories, Inc.
36 * All or some portions of this file are derived from material licensed
37 * to the University of California by American Telephone and Telegraph
38 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
39 * the permission of UNIX System Laboratories, Inc.
40 *
41 * Redistribution and use in source and binary forms, with or without
42 * modification, are permitted provided that the following conditions
43 * are met:
44 * 1. Redistributions of source code must retain the above copyright
45 * notice, this list of conditions and the following disclaimer.
46 * 2. Redistributions in binary form must reproduce the above copyright
47 * notice, this list of conditions and the following disclaimer in the
48 * documentation and/or other materials provided with the distribution.
49 * 3. Neither the name of the University nor the names of its contributors
50 * may be used to endorse or promote products derived from this software
51 * without specific prior written permission.
52 *
53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
63 * SUCH DAMAGE.
64 *
65 * @(#)kern_descrip.c 8.8 (Berkeley) 2/14/95
66 */
67
68 /*
69 * File descriptor management.
70 */
71
72 #include <sys/cdefs.h>
73 __KERNEL_RCSID(0, "$NetBSD: kern_descrip.c,v 1.251 2021/06/29 22:40:53 dholland Exp $");
74
75 #include <sys/param.h>
76 #include <sys/systm.h>
77 #include <sys/filedesc.h>
78 #include <sys/kernel.h>
79 #include <sys/proc.h>
80 #include <sys/file.h>
81 #include <sys/socket.h>
82 #include <sys/socketvar.h>
83 #include <sys/stat.h>
84 #include <sys/ioctl.h>
85 #include <sys/fcntl.h>
86 #include <sys/pool.h>
87 #include <sys/unistd.h>
88 #include <sys/resourcevar.h>
89 #include <sys/conf.h>
90 #include <sys/event.h>
91 #include <sys/kauth.h>
92 #include <sys/atomic.h>
93 #include <sys/syscallargs.h>
94 #include <sys/cpu.h>
95 #include <sys/kmem.h>
96 #include <sys/vnode.h>
97 #include <sys/sysctl.h>
98 #include <sys/ktrace.h>
99
100 /*
101 * A list (head) of open files, counter, and lock protecting them.
102 */
103 struct filelist filehead __cacheline_aligned;
104 static u_int nfiles __cacheline_aligned;
105 kmutex_t filelist_lock __cacheline_aligned;
106
107 static pool_cache_t filedesc_cache __read_mostly;
108 static pool_cache_t file_cache __read_mostly;
109 static pool_cache_t fdfile_cache __read_mostly;
110
111 static int file_ctor(void *, void *, int);
112 static void file_dtor(void *, void *);
113 static int fdfile_ctor(void *, void *, int);
114 static void fdfile_dtor(void *, void *);
115 static int filedesc_ctor(void *, void *, int);
116 static void filedesc_dtor(void *, void *);
117 static int filedescopen(dev_t, int, int, lwp_t *);
118
119 static int sysctl_kern_file(SYSCTLFN_PROTO);
120 static int sysctl_kern_file2(SYSCTLFN_PROTO);
121 static void fill_file(struct file *, const struct file *);
122 static void fill_file2(struct kinfo_file *, const file_t *, const fdfile_t *,
123 int, pid_t);
124
125 const struct cdevsw filedesc_cdevsw = {
126 .d_open = filedescopen,
127 .d_close = noclose,
128 .d_read = noread,
129 .d_write = nowrite,
130 .d_ioctl = noioctl,
131 .d_stop = nostop,
132 .d_tty = notty,
133 .d_poll = nopoll,
134 .d_mmap = nommap,
135 .d_kqfilter = nokqfilter,
136 .d_discard = nodiscard,
137 .d_flag = D_OTHER | D_MPSAFE
138 };
139
140 /* For ease of reading. */
141 __strong_alias(fd_putvnode,fd_putfile)
142 __strong_alias(fd_putsock,fd_putfile)
143
144 /*
145 * Initialize the descriptor system.
146 */
147 void
148 fd_sys_init(void)
149 {
150 static struct sysctllog *clog;
151
152 mutex_init(&filelist_lock, MUTEX_DEFAULT, IPL_NONE);
153
154 LIST_INIT(&filehead);
155
156 file_cache = pool_cache_init(sizeof(file_t), coherency_unit, 0,
157 0, "file", NULL, IPL_NONE, file_ctor, file_dtor, NULL);
158 KASSERT(file_cache != NULL);
159
160 fdfile_cache = pool_cache_init(sizeof(fdfile_t), coherency_unit, 0,
161 PR_LARGECACHE, "fdfile", NULL, IPL_NONE, fdfile_ctor, fdfile_dtor,
162 NULL);
163 KASSERT(fdfile_cache != NULL);
164
165 filedesc_cache = pool_cache_init(sizeof(filedesc_t), coherency_unit,
166 0, 0, "filedesc", NULL, IPL_NONE, filedesc_ctor, filedesc_dtor,
167 NULL);
168 KASSERT(filedesc_cache != NULL);
169
170 sysctl_createv(&clog, 0, NULL, NULL,
171 CTLFLAG_PERMANENT,
172 CTLTYPE_STRUCT, "file",
173 SYSCTL_DESCR("System open file table"),
174 sysctl_kern_file, 0, NULL, 0,
175 CTL_KERN, KERN_FILE, CTL_EOL);
176 sysctl_createv(&clog, 0, NULL, NULL,
177 CTLFLAG_PERMANENT,
178 CTLTYPE_STRUCT, "file2",
179 SYSCTL_DESCR("System open file table"),
180 sysctl_kern_file2, 0, NULL, 0,
181 CTL_KERN, KERN_FILE2, CTL_EOL);
182 }
183
184 static bool
185 fd_isused(filedesc_t *fdp, unsigned fd)
186 {
187 u_int off = fd >> NDENTRYSHIFT;
188
189 KASSERT(fd < atomic_load_consume(&fdp->fd_dt)->dt_nfiles);
190
191 return (fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK))) != 0;
192 }
193
194 /*
195 * Verify that the bitmaps match the descriptor table.
196 */
197 static inline void
198 fd_checkmaps(filedesc_t *fdp)
199 {
200 #ifdef DEBUG
201 fdtab_t *dt;
202 u_int fd;
203
204 KASSERT(fdp->fd_refcnt <= 1 || mutex_owned(&fdp->fd_lock));
205
206 dt = fdp->fd_dt;
207 if (fdp->fd_refcnt == -1) {
208 /*
209 * fd_free tears down the table without maintaining its bitmap.
210 */
211 return;
212 }
213 for (fd = 0; fd < dt->dt_nfiles; fd++) {
214 if (fd < NDFDFILE) {
215 KASSERT(dt->dt_ff[fd] ==
216 (fdfile_t *)fdp->fd_dfdfile[fd]);
217 }
218 if (dt->dt_ff[fd] == NULL) {
219 KASSERT(!fd_isused(fdp, fd));
220 } else if (dt->dt_ff[fd]->ff_file != NULL) {
221 KASSERT(fd_isused(fdp, fd));
222 }
223 }
224 #endif
225 }
226
227 static int
228 fd_next_zero(filedesc_t *fdp, uint32_t *bitmap, int want, u_int bits)
229 {
230 int i, off, maxoff;
231 uint32_t sub;
232
233 KASSERT(mutex_owned(&fdp->fd_lock));
234
235 fd_checkmaps(fdp);
236
237 if (want > bits)
238 return -1;
239
240 off = want >> NDENTRYSHIFT;
241 i = want & NDENTRYMASK;
242 if (i) {
243 sub = bitmap[off] | ((u_int)~0 >> (NDENTRIES - i));
244 if (sub != ~0)
245 goto found;
246 off++;
247 }
248
249 maxoff = NDLOSLOTS(bits);
250 while (off < maxoff) {
251 if ((sub = bitmap[off]) != ~0)
252 goto found;
253 off++;
254 }
255
256 return -1;
257
258 found:
259 return (off << NDENTRYSHIFT) + ffs(~sub) - 1;
260 }
261
262 static int
263 fd_last_set(filedesc_t *fd, int last)
264 {
265 int off, i;
266 fdfile_t **ff = fd->fd_dt->dt_ff;
267 uint32_t *bitmap = fd->fd_lomap;
268
269 KASSERT(mutex_owned(&fd->fd_lock));
270
271 fd_checkmaps(fd);
272
273 off = (last - 1) >> NDENTRYSHIFT;
274
275 while (off >= 0 && !bitmap[off])
276 off--;
277
278 if (off < 0)
279 return -1;
280
281 i = ((off + 1) << NDENTRYSHIFT) - 1;
282 if (i >= last)
283 i = last - 1;
284
285 /* XXX should use bitmap */
286 while (i > 0 && (ff[i] == NULL || !ff[i]->ff_allocated))
287 i--;
288
289 return i;
290 }
291
292 static inline void
293 fd_used(filedesc_t *fdp, unsigned fd)
294 {
295 u_int off = fd >> NDENTRYSHIFT;
296 fdfile_t *ff;
297
298 ff = fdp->fd_dt->dt_ff[fd];
299
300 KASSERT(mutex_owned(&fdp->fd_lock));
301 KASSERT((fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK))) == 0);
302 KASSERT(ff != NULL);
303 KASSERT(ff->ff_file == NULL);
304 KASSERT(!ff->ff_allocated);
305
306 ff->ff_allocated = true;
307 fdp->fd_lomap[off] |= 1U << (fd & NDENTRYMASK);
308 if (__predict_false(fdp->fd_lomap[off] == ~0)) {
309 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] &
310 (1U << (off & NDENTRYMASK))) == 0);
311 fdp->fd_himap[off >> NDENTRYSHIFT] |= 1U << (off & NDENTRYMASK);
312 }
313
314 if ((int)fd > fdp->fd_lastfile) {
315 fdp->fd_lastfile = fd;
316 }
317
318 fd_checkmaps(fdp);
319 }
320
321 static inline void
322 fd_unused(filedesc_t *fdp, unsigned fd)
323 {
324 u_int off = fd >> NDENTRYSHIFT;
325 fdfile_t *ff;
326
327 ff = fdp->fd_dt->dt_ff[fd];
328
329 KASSERT(mutex_owned(&fdp->fd_lock));
330 KASSERT(ff != NULL);
331 KASSERT(ff->ff_file == NULL);
332 KASSERT(ff->ff_allocated);
333
334 if (fd < fdp->fd_freefile) {
335 fdp->fd_freefile = fd;
336 }
337
338 if (fdp->fd_lomap[off] == ~0) {
339 KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] &
340 (1U << (off & NDENTRYMASK))) != 0);
341 fdp->fd_himap[off >> NDENTRYSHIFT] &=
342 ~(1U << (off & NDENTRYMASK));
343 }
344 KASSERT((fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK))) != 0);
345 fdp->fd_lomap[off] &= ~(1U << (fd & NDENTRYMASK));
346 ff->ff_allocated = false;
347
348 KASSERT(fd <= fdp->fd_lastfile);
349 if (fd == fdp->fd_lastfile) {
350 fdp->fd_lastfile = fd_last_set(fdp, fd);
351 }
352 fd_checkmaps(fdp);
353 }
354
355 /*
356 * Look up the file structure corresponding to a file descriptor
357 * and return the file, holding a reference on the descriptor.
358 */
359 file_t *
360 fd_getfile(unsigned fd)
361 {
362 filedesc_t *fdp;
363 fdfile_t *ff;
364 file_t *fp;
365 fdtab_t *dt;
366
367 /*
368 * Look up the fdfile structure representing this descriptor.
369 * We are doing this unlocked. See fd_tryexpand().
370 */
371 fdp = curlwp->l_fd;
372 dt = atomic_load_consume(&fdp->fd_dt);
373 if (__predict_false(fd >= dt->dt_nfiles)) {
374 return NULL;
375 }
376 ff = dt->dt_ff[fd];
377 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
378 if (__predict_false(ff == NULL)) {
379 return NULL;
380 }
381
382 /* Now get a reference to the descriptor. */
383 if (fdp->fd_refcnt == 1) {
384 /*
385 * Single threaded: don't need to worry about concurrent
386 * access (other than earlier calls to kqueue, which may
387 * hold a reference to the descriptor).
388 */
389 ff->ff_refcnt++;
390 } else {
391 /*
392 * Multi threaded: issue a memory barrier to ensure that we
393 * acquire the file pointer _after_ adding a reference. If
394 * no memory barrier, we could fetch a stale pointer.
395 */
396 atomic_inc_uint(&ff->ff_refcnt);
397 #ifndef __HAVE_ATOMIC_AS_MEMBAR
398 membar_enter();
399 #endif
400 }
401
402 /*
403 * If the file is not open or is being closed then put the
404 * reference back.
405 */
406 fp = atomic_load_consume(&ff->ff_file);
407 if (__predict_true(fp != NULL)) {
408 return fp;
409 }
410 fd_putfile(fd);
411 return NULL;
412 }
413
414 /*
415 * Release a reference to a file descriptor acquired with fd_getfile().
416 */
417 void
418 fd_putfile(unsigned fd)
419 {
420 filedesc_t *fdp;
421 fdfile_t *ff;
422 u_int u, v;
423
424 fdp = curlwp->l_fd;
425 KASSERT(fd < atomic_load_consume(&fdp->fd_dt)->dt_nfiles);
426 ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd];
427
428 KASSERT(ff != NULL);
429 KASSERT((ff->ff_refcnt & FR_MASK) > 0);
430 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
431
432 if (fdp->fd_refcnt == 1) {
433 /*
434 * Single threaded: don't need to worry about concurrent
435 * access (other than earlier calls to kqueue, which may
436 * hold a reference to the descriptor).
437 */
438 if (__predict_false((ff->ff_refcnt & FR_CLOSING) != 0)) {
439 fd_close(fd);
440 return;
441 }
442 ff->ff_refcnt--;
443 return;
444 }
445
446 /*
447 * Ensure that any use of the file is complete and globally
448 * visible before dropping the final reference. If no membar,
449 * the current CPU could still access memory associated with
450 * the file after it has been freed or recycled by another
451 * CPU.
452 */
453 #ifndef __HAVE_ATOMIC_AS_MEMBAR
454 membar_exit();
455 #endif
456
457 /*
458 * Be optimistic and start out with the assumption that no other
459 * threads are trying to close the descriptor. If the CAS fails,
460 * we lost a race and/or it's being closed.
461 */
462 for (u = ff->ff_refcnt & FR_MASK;; u = v) {
463 v = atomic_cas_uint(&ff->ff_refcnt, u, u - 1);
464 if (__predict_true(u == v)) {
465 return;
466 }
467 if (__predict_false((v & FR_CLOSING) != 0)) {
468 break;
469 }
470 }
471
472 /* Another thread is waiting to close the file: join it. */
473 (void)fd_close(fd);
474 }
475
476 /*
477 * Convenience wrapper around fd_getfile() that returns reference
478 * to a vnode.
479 */
480 int
481 fd_getvnode(unsigned fd, file_t **fpp)
482 {
483 vnode_t *vp;
484 file_t *fp;
485
486 fp = fd_getfile(fd);
487 if (__predict_false(fp == NULL)) {
488 return EBADF;
489 }
490 if (__predict_false(fp->f_type != DTYPE_VNODE)) {
491 fd_putfile(fd);
492 return EINVAL;
493 }
494 vp = fp->f_vnode;
495 if (__predict_false(vp->v_type == VBAD)) {
496 /* XXX Is this case really necessary? */
497 fd_putfile(fd);
498 return EBADF;
499 }
500 *fpp = fp;
501 return 0;
502 }
503
504 /*
505 * Convenience wrapper around fd_getfile() that returns reference
506 * to a socket.
507 */
508 int
509 fd_getsock1(unsigned fd, struct socket **sop, file_t **fp)
510 {
511 *fp = fd_getfile(fd);
512 if (__predict_false(*fp == NULL)) {
513 return EBADF;
514 }
515 if (__predict_false((*fp)->f_type != DTYPE_SOCKET)) {
516 fd_putfile(fd);
517 return ENOTSOCK;
518 }
519 *sop = (*fp)->f_socket;
520 return 0;
521 }
522
523 int
524 fd_getsock(unsigned fd, struct socket **sop)
525 {
526 file_t *fp;
527 return fd_getsock1(fd, sop, &fp);
528 }
529
530 /*
531 * Look up the file structure corresponding to a file descriptor
532 * and return it with a reference held on the file, not the
533 * descriptor.
534 *
535 * This is heavyweight and only used when accessing descriptors
536 * from a foreign process. The caller must ensure that `p' does
537 * not exit or fork across this call.
538 *
539 * To release the file (not descriptor) reference, use closef().
540 */
541 file_t *
542 fd_getfile2(proc_t *p, unsigned fd)
543 {
544 filedesc_t *fdp;
545 fdfile_t *ff;
546 file_t *fp;
547 fdtab_t *dt;
548
549 fdp = p->p_fd;
550 mutex_enter(&fdp->fd_lock);
551 dt = fdp->fd_dt;
552 if (fd >= dt->dt_nfiles) {
553 mutex_exit(&fdp->fd_lock);
554 return NULL;
555 }
556 if ((ff = dt->dt_ff[fd]) == NULL) {
557 mutex_exit(&fdp->fd_lock);
558 return NULL;
559 }
560 if ((fp = atomic_load_consume(&ff->ff_file)) == NULL) {
561 mutex_exit(&fdp->fd_lock);
562 return NULL;
563 }
564 mutex_enter(&fp->f_lock);
565 fp->f_count++;
566 mutex_exit(&fp->f_lock);
567 mutex_exit(&fdp->fd_lock);
568
569 return fp;
570 }
571
572 /*
573 * Internal form of close. Must be called with a reference to the
574 * descriptor, and will drop the reference. When all descriptor
575 * references are dropped, releases the descriptor slot and a single
576 * reference to the file structure.
577 */
578 int
579 fd_close(unsigned fd)
580 {
581 struct flock lf;
582 filedesc_t *fdp;
583 fdfile_t *ff;
584 file_t *fp;
585 proc_t *p;
586 lwp_t *l;
587 u_int refcnt;
588
589 l = curlwp;
590 p = l->l_proc;
591 fdp = l->l_fd;
592 ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd];
593
594 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
595
596 mutex_enter(&fdp->fd_lock);
597 KASSERT((ff->ff_refcnt & FR_MASK) > 0);
598 fp = atomic_load_consume(&ff->ff_file);
599 if (__predict_false(fp == NULL)) {
600 /*
601 * Another user of the file is already closing, and is
602 * waiting for other users of the file to drain. Release
603 * our reference, and wake up the closer.
604 */
605 atomic_dec_uint(&ff->ff_refcnt);
606 cv_broadcast(&ff->ff_closing);
607 mutex_exit(&fdp->fd_lock);
608
609 /*
610 * An application error, so pretend that the descriptor
611 * was already closed. We can't safely wait for it to
612 * be closed without potentially deadlocking.
613 */
614 return (EBADF);
615 }
616 KASSERT((ff->ff_refcnt & FR_CLOSING) == 0);
617
618 /*
619 * There may be multiple users of this file within the process.
620 * Notify existing and new users that the file is closing. This
621 * will prevent them from adding additional uses to this file
622 * while we are closing it.
623 */
624 ff->ff_file = NULL;
625 ff->ff_exclose = false;
626
627 /*
628 * We expect the caller to hold a descriptor reference - drop it.
629 * The reference count may increase beyond zero at this point due
630 * to an erroneous descriptor reference by an application, but
631 * fd_getfile() will notice that the file is being closed and drop
632 * the reference again.
633 */
634 if (fdp->fd_refcnt == 1) {
635 /* Single threaded. */
636 refcnt = --(ff->ff_refcnt);
637 } else {
638 /* Multi threaded. */
639 #ifndef __HAVE_ATOMIC_AS_MEMBAR
640 membar_producer();
641 #endif
642 refcnt = atomic_dec_uint_nv(&ff->ff_refcnt);
643 }
644 if (__predict_false(refcnt != 0)) {
645 /*
646 * Wait for other references to drain. This is typically
647 * an application error - the descriptor is being closed
648 * while still in use.
649 * (Or just a threaded application trying to unblock its
650 * thread that sleeps in (say) accept()).
651 */
652 atomic_or_uint(&ff->ff_refcnt, FR_CLOSING);
653
654 /*
655 * Remove any knotes attached to the file. A knote
656 * attached to the descriptor can hold references on it.
657 */
658 mutex_exit(&fdp->fd_lock);
659 if (!SLIST_EMPTY(&ff->ff_knlist)) {
660 knote_fdclose(fd);
661 }
662
663 /*
664 * Since the file system code doesn't know which fd
665 * each request came from (think dup()), we have to
666 * ask it to return ERESTART for any long-term blocks.
667 * The re-entry through read/write/etc will detect the
668 * closed fd and return EBAFD.
669 * Blocked partial writes may return a short length.
670 */
671 (*fp->f_ops->fo_restart)(fp);
672 mutex_enter(&fdp->fd_lock);
673
674 /*
675 * We need to see the count drop to zero at least once,
676 * in order to ensure that all pre-existing references
677 * have been drained. New references past this point are
678 * of no interest.
679 * XXX (dsl) this may need to call fo_restart() after a
680 * timeout to guarantee that all the system calls exit.
681 */
682 while ((ff->ff_refcnt & FR_MASK) != 0) {
683 cv_wait(&ff->ff_closing, &fdp->fd_lock);
684 }
685 atomic_and_uint(&ff->ff_refcnt, ~FR_CLOSING);
686 } else {
687 /* If no references, there must be no knotes. */
688 KASSERT(SLIST_EMPTY(&ff->ff_knlist));
689 }
690
691 /*
692 * POSIX record locking dictates that any close releases ALL
693 * locks owned by this process. This is handled by setting
694 * a flag in the unlock to free ONLY locks obeying POSIX
695 * semantics, and not to free BSD-style file locks.
696 * If the descriptor was in a message, POSIX-style locks
697 * aren't passed with the descriptor.
698 */
699 if (__predict_false((p->p_flag & PK_ADVLOCK) != 0 &&
700 fp->f_type == DTYPE_VNODE)) {
701 lf.l_whence = SEEK_SET;
702 lf.l_start = 0;
703 lf.l_len = 0;
704 lf.l_type = F_UNLCK;
705 mutex_exit(&fdp->fd_lock);
706 (void)VOP_ADVLOCK(fp->f_vnode, p, F_UNLCK, &lf, F_POSIX);
707 mutex_enter(&fdp->fd_lock);
708 }
709
710 /* Free descriptor slot. */
711 fd_unused(fdp, fd);
712 mutex_exit(&fdp->fd_lock);
713
714 /* Now drop reference to the file itself. */
715 return closef(fp);
716 }
717
718 /*
719 * Duplicate a file descriptor.
720 */
721 int
722 fd_dup(file_t *fp, int minfd, int *newp, bool exclose)
723 {
724 proc_t *p = curproc;
725 fdtab_t *dt;
726 int error;
727
728 while ((error = fd_alloc(p, minfd, newp)) != 0) {
729 if (error != ENOSPC) {
730 return error;
731 }
732 fd_tryexpand(p);
733 }
734
735 dt = atomic_load_consume(&curlwp->l_fd->fd_dt);
736 dt->dt_ff[*newp]->ff_exclose = exclose;
737 fd_affix(p, fp, *newp);
738 return 0;
739 }
740
741 /*
742 * dup2 operation.
743 */
744 int
745 fd_dup2(file_t *fp, unsigned newfd, int flags)
746 {
747 filedesc_t *fdp = curlwp->l_fd;
748 fdfile_t *ff;
749 fdtab_t *dt;
750
751 if (flags & ~(O_CLOEXEC|O_NONBLOCK|O_NOSIGPIPE))
752 return EINVAL;
753 /*
754 * Ensure there are enough slots in the descriptor table,
755 * and allocate an fdfile_t up front in case we need it.
756 */
757 while (newfd >= atomic_load_consume(&fdp->fd_dt)->dt_nfiles) {
758 fd_tryexpand(curproc);
759 }
760 ff = pool_cache_get(fdfile_cache, PR_WAITOK);
761
762 /*
763 * If there is already a file open, close it. If the file is
764 * half open, wait for it to be constructed before closing it.
765 * XXX Potential for deadlock here?
766 */
767 mutex_enter(&fdp->fd_lock);
768 while (fd_isused(fdp, newfd)) {
769 mutex_exit(&fdp->fd_lock);
770 if (fd_getfile(newfd) != NULL) {
771 (void)fd_close(newfd);
772 } else {
773 /*
774 * Crummy, but unlikely to happen.
775 * Can occur if we interrupt another
776 * thread while it is opening a file.
777 */
778 kpause("dup2", false, 1, NULL);
779 }
780 mutex_enter(&fdp->fd_lock);
781 }
782 dt = fdp->fd_dt;
783 if (dt->dt_ff[newfd] == NULL) {
784 KASSERT(newfd >= NDFDFILE);
785 dt->dt_ff[newfd] = ff;
786 ff = NULL;
787 }
788 fd_used(fdp, newfd);
789 mutex_exit(&fdp->fd_lock);
790
791 dt->dt_ff[newfd]->ff_exclose = (flags & O_CLOEXEC) != 0;
792 fp->f_flag |= flags & (FNONBLOCK|FNOSIGPIPE);
793 /* Slot is now allocated. Insert copy of the file. */
794 fd_affix(curproc, fp, newfd);
795 if (ff != NULL) {
796 pool_cache_put(fdfile_cache, ff);
797 }
798 return 0;
799 }
800
801 /*
802 * Drop reference to a file structure.
803 */
804 int
805 closef(file_t *fp)
806 {
807 struct flock lf;
808 int error;
809
810 /*
811 * Drop reference. If referenced elsewhere it's still open
812 * and we have nothing more to do.
813 */
814 mutex_enter(&fp->f_lock);
815 KASSERT(fp->f_count > 0);
816 if (--fp->f_count > 0) {
817 mutex_exit(&fp->f_lock);
818 return 0;
819 }
820 KASSERT(fp->f_count == 0);
821 mutex_exit(&fp->f_lock);
822
823 /* We held the last reference - release locks, close and free. */
824 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) {
825 lf.l_whence = SEEK_SET;
826 lf.l_start = 0;
827 lf.l_len = 0;
828 lf.l_type = F_UNLCK;
829 (void)VOP_ADVLOCK(fp->f_vnode, fp, F_UNLCK, &lf, F_FLOCK);
830 }
831 if (fp->f_ops != NULL) {
832 error = (*fp->f_ops->fo_close)(fp);
833 } else {
834 error = 0;
835 }
836 KASSERT(fp->f_count == 0);
837 KASSERT(fp->f_cred != NULL);
838 pool_cache_put(file_cache, fp);
839
840 return error;
841 }
842
843 /*
844 * Allocate a file descriptor for the process.
845 */
846 int
847 fd_alloc(proc_t *p, int want, int *result)
848 {
849 filedesc_t *fdp = p->p_fd;
850 int i, lim, last, error, hi;
851 u_int off;
852 fdtab_t *dt;
853
854 KASSERT(p == curproc || p == &proc0);
855
856 /*
857 * Search for a free descriptor starting at the higher
858 * of want or fd_freefile.
859 */
860 mutex_enter(&fdp->fd_lock);
861 fd_checkmaps(fdp);
862 dt = fdp->fd_dt;
863 KASSERT(dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]);
864 lim = uimin((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles);
865 last = uimin(dt->dt_nfiles, lim);
866 for (;;) {
867 if ((i = want) < fdp->fd_freefile)
868 i = fdp->fd_freefile;
869 off = i >> NDENTRYSHIFT;
870 hi = fd_next_zero(fdp, fdp->fd_himap, off,
871 (last + NDENTRIES - 1) >> NDENTRYSHIFT);
872 if (hi == -1)
873 break;
874 i = fd_next_zero(fdp, &fdp->fd_lomap[hi],
875 hi > off ? 0 : i & NDENTRYMASK, NDENTRIES);
876 if (i == -1) {
877 /*
878 * Free file descriptor in this block was
879 * below want, try again with higher want.
880 */
881 want = (hi + 1) << NDENTRYSHIFT;
882 continue;
883 }
884 i += (hi << NDENTRYSHIFT);
885 if (i >= last) {
886 break;
887 }
888 if (dt->dt_ff[i] == NULL) {
889 KASSERT(i >= NDFDFILE);
890 dt->dt_ff[i] = pool_cache_get(fdfile_cache, PR_WAITOK);
891 }
892 KASSERT(dt->dt_ff[i]->ff_file == NULL);
893 fd_used(fdp, i);
894 if (want <= fdp->fd_freefile) {
895 fdp->fd_freefile = i;
896 }
897 *result = i;
898 KASSERT(i >= NDFDFILE ||
899 dt->dt_ff[i] == (fdfile_t *)fdp->fd_dfdfile[i]);
900 fd_checkmaps(fdp);
901 mutex_exit(&fdp->fd_lock);
902 return 0;
903 }
904
905 /* No space in current array. Let the caller expand and retry. */
906 error = (dt->dt_nfiles >= lim) ? EMFILE : ENOSPC;
907 mutex_exit(&fdp->fd_lock);
908 return error;
909 }
910
911 /*
912 * Allocate memory for a descriptor table.
913 */
914 static fdtab_t *
915 fd_dtab_alloc(int n)
916 {
917 fdtab_t *dt;
918 size_t sz;
919
920 KASSERT(n > NDFILE);
921
922 sz = sizeof(*dt) + (n - NDFILE) * sizeof(dt->dt_ff[0]);
923 dt = kmem_alloc(sz, KM_SLEEP);
924 #ifdef DIAGNOSTIC
925 memset(dt, 0xff, sz);
926 #endif
927 dt->dt_nfiles = n;
928 dt->dt_link = NULL;
929 return dt;
930 }
931
932 /*
933 * Free a descriptor table, and all tables linked for deferred free.
934 */
935 static void
936 fd_dtab_free(fdtab_t *dt)
937 {
938 fdtab_t *next;
939 size_t sz;
940
941 do {
942 next = dt->dt_link;
943 KASSERT(dt->dt_nfiles > NDFILE);
944 sz = sizeof(*dt) +
945 (dt->dt_nfiles - NDFILE) * sizeof(dt->dt_ff[0]);
946 #ifdef DIAGNOSTIC
947 memset(dt, 0xff, sz);
948 #endif
949 kmem_free(dt, sz);
950 dt = next;
951 } while (dt != NULL);
952 }
953
954 /*
955 * Allocate descriptor bitmap.
956 */
957 static void
958 fd_map_alloc(int n, uint32_t **lo, uint32_t **hi)
959 {
960 uint8_t *ptr;
961 size_t szlo, szhi;
962
963 KASSERT(n > NDENTRIES);
964
965 szlo = NDLOSLOTS(n) * sizeof(uint32_t);
966 szhi = NDHISLOTS(n) * sizeof(uint32_t);
967 ptr = kmem_alloc(szlo + szhi, KM_SLEEP);
968 *lo = (uint32_t *)ptr;
969 *hi = (uint32_t *)(ptr + szlo);
970 }
971
972 /*
973 * Free descriptor bitmap.
974 */
975 static void
976 fd_map_free(int n, uint32_t *lo, uint32_t *hi)
977 {
978 size_t szlo, szhi;
979
980 KASSERT(n > NDENTRIES);
981
982 szlo = NDLOSLOTS(n) * sizeof(uint32_t);
983 szhi = NDHISLOTS(n) * sizeof(uint32_t);
984 KASSERT(hi == (uint32_t *)((uint8_t *)lo + szlo));
985 kmem_free(lo, szlo + szhi);
986 }
987
988 /*
989 * Expand a process' descriptor table.
990 */
991 void
992 fd_tryexpand(proc_t *p)
993 {
994 filedesc_t *fdp;
995 int i, numfiles, oldnfiles;
996 fdtab_t *newdt, *dt;
997 uint32_t *newhimap, *newlomap;
998
999 KASSERT(p == curproc || p == &proc0);
1000
1001 fdp = p->p_fd;
1002 newhimap = NULL;
1003 newlomap = NULL;
1004 oldnfiles = atomic_load_consume(&fdp->fd_dt)->dt_nfiles;
1005
1006 if (oldnfiles < NDEXTENT)
1007 numfiles = NDEXTENT;
1008 else
1009 numfiles = 2 * oldnfiles;
1010
1011 newdt = fd_dtab_alloc(numfiles);
1012 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) {
1013 fd_map_alloc(numfiles, &newlomap, &newhimap);
1014 }
1015
1016 mutex_enter(&fdp->fd_lock);
1017 dt = fdp->fd_dt;
1018 KASSERT(dt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]);
1019 if (dt->dt_nfiles != oldnfiles) {
1020 /* fdp changed; caller must retry */
1021 mutex_exit(&fdp->fd_lock);
1022 fd_dtab_free(newdt);
1023 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) {
1024 fd_map_free(numfiles, newlomap, newhimap);
1025 }
1026 return;
1027 }
1028
1029 /* Copy the existing descriptor table and zero the new portion. */
1030 i = sizeof(fdfile_t *) * oldnfiles;
1031 memcpy(newdt->dt_ff, dt->dt_ff, i);
1032 memset((uint8_t *)newdt->dt_ff + i, 0,
1033 numfiles * sizeof(fdfile_t *) - i);
1034
1035 /*
1036 * Link old descriptor array into list to be discarded. We defer
1037 * freeing until the last reference to the descriptor table goes
1038 * away (usually process exit). This allows us to do lockless
1039 * lookups in fd_getfile().
1040 */
1041 if (oldnfiles > NDFILE) {
1042 if (fdp->fd_refcnt > 1) {
1043 newdt->dt_link = dt;
1044 } else {
1045 fd_dtab_free(dt);
1046 }
1047 }
1048
1049 if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) {
1050 i = NDHISLOTS(oldnfiles) * sizeof(uint32_t);
1051 memcpy(newhimap, fdp->fd_himap, i);
1052 memset((uint8_t *)newhimap + i, 0,
1053 NDHISLOTS(numfiles) * sizeof(uint32_t) - i);
1054
1055 i = NDLOSLOTS(oldnfiles) * sizeof(uint32_t);
1056 memcpy(newlomap, fdp->fd_lomap, i);
1057 memset((uint8_t *)newlomap + i, 0,
1058 NDLOSLOTS(numfiles) * sizeof(uint32_t) - i);
1059
1060 if (NDHISLOTS(oldnfiles) > NDHISLOTS(NDFILE)) {
1061 fd_map_free(oldnfiles, fdp->fd_lomap, fdp->fd_himap);
1062 }
1063 fdp->fd_himap = newhimap;
1064 fdp->fd_lomap = newlomap;
1065 }
1066
1067 /*
1068 * All other modifications must become globally visible before
1069 * the change to fd_dt. See fd_getfile().
1070 */
1071 atomic_store_release(&fdp->fd_dt, newdt);
1072 KASSERT(newdt->dt_ff[0] == (fdfile_t *)fdp->fd_dfdfile[0]);
1073 fd_checkmaps(fdp);
1074 mutex_exit(&fdp->fd_lock);
1075 }
1076
1077 /*
1078 * Create a new open file structure and allocate a file descriptor
1079 * for the current process.
1080 */
1081 int
1082 fd_allocfile(file_t **resultfp, int *resultfd)
1083 {
1084 proc_t *p = curproc;
1085 kauth_cred_t cred;
1086 file_t *fp;
1087 int error;
1088
1089 while ((error = fd_alloc(p, 0, resultfd)) != 0) {
1090 if (error != ENOSPC) {
1091 return error;
1092 }
1093 fd_tryexpand(p);
1094 }
1095
1096 fp = pool_cache_get(file_cache, PR_WAITOK);
1097 if (fp == NULL) {
1098 fd_abort(p, NULL, *resultfd);
1099 return ENFILE;
1100 }
1101 KASSERT(fp->f_count == 0);
1102 KASSERT(fp->f_msgcount == 0);
1103 KASSERT(fp->f_unpcount == 0);
1104
1105 /* Replace cached credentials if not what we need. */
1106 cred = curlwp->l_cred;
1107 if (__predict_false(cred != fp->f_cred)) {
1108 kauth_cred_free(fp->f_cred);
1109 kauth_cred_hold(cred);
1110 fp->f_cred = cred;
1111 }
1112
1113 /*
1114 * Don't allow recycled files to be scanned.
1115 * See uipc_usrreq.c.
1116 */
1117 if (__predict_false((fp->f_flag & FSCAN) != 0)) {
1118 mutex_enter(&fp->f_lock);
1119 atomic_and_uint(&fp->f_flag, ~FSCAN);
1120 mutex_exit(&fp->f_lock);
1121 }
1122
1123 fp->f_advice = 0;
1124 fp->f_offset = 0;
1125 *resultfp = fp;
1126
1127 return 0;
1128 }
1129
1130 /*
1131 * Successful creation of a new descriptor: make visible to the process.
1132 */
1133 void
1134 fd_affix(proc_t *p, file_t *fp, unsigned fd)
1135 {
1136 fdfile_t *ff;
1137 filedesc_t *fdp;
1138 fdtab_t *dt;
1139
1140 KASSERT(p == curproc || p == &proc0);
1141
1142 /* Add a reference to the file structure. */
1143 mutex_enter(&fp->f_lock);
1144 fp->f_count++;
1145 mutex_exit(&fp->f_lock);
1146
1147 /*
1148 * Insert the new file into the descriptor slot.
1149 *
1150 * The memory barriers provided by lock activity in this routine
1151 * ensure that any updates to the file structure become globally
1152 * visible before the file becomes visible to other LWPs in the
1153 * current process; otherwise we would set ff->ff_file with
1154 * atomic_store_release(&ff->ff_file, fp) at the bottom.
1155 */
1156 fdp = p->p_fd;
1157 dt = atomic_load_consume(&fdp->fd_dt);
1158 ff = dt->dt_ff[fd];
1159
1160 KASSERT(ff != NULL);
1161 KASSERT(ff->ff_file == NULL);
1162 KASSERT(ff->ff_allocated);
1163 KASSERT(fd_isused(fdp, fd));
1164 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
1165
1166 /* No need to lock in order to make file initially visible. */
1167 ff->ff_file = fp;
1168 }
1169
1170 /*
1171 * Abort creation of a new descriptor: free descriptor slot and file.
1172 */
1173 void
1174 fd_abort(proc_t *p, file_t *fp, unsigned fd)
1175 {
1176 filedesc_t *fdp;
1177 fdfile_t *ff;
1178
1179 KASSERT(p == curproc || p == &proc0);
1180
1181 fdp = p->p_fd;
1182 ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd];
1183 ff->ff_exclose = false;
1184
1185 KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
1186
1187 mutex_enter(&fdp->fd_lock);
1188 KASSERT(fd_isused(fdp, fd));
1189 fd_unused(fdp, fd);
1190 mutex_exit(&fdp->fd_lock);
1191
1192 if (fp != NULL) {
1193 KASSERT(fp->f_count == 0);
1194 KASSERT(fp->f_cred != NULL);
1195 pool_cache_put(file_cache, fp);
1196 }
1197 }
1198
1199 static int
1200 file_ctor(void *arg, void *obj, int flags)
1201 {
1202 file_t *fp = obj;
1203
1204 memset(fp, 0, sizeof(*fp));
1205
1206 mutex_enter(&filelist_lock);
1207 if (__predict_false(nfiles >= maxfiles)) {
1208 mutex_exit(&filelist_lock);
1209 tablefull("file", "increase kern.maxfiles or MAXFILES");
1210 return ENFILE;
1211 }
1212 nfiles++;
1213 LIST_INSERT_HEAD(&filehead, fp, f_list);
1214 mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE);
1215 fp->f_cred = curlwp->l_cred;
1216 kauth_cred_hold(fp->f_cred);
1217 mutex_exit(&filelist_lock);
1218
1219 return 0;
1220 }
1221
1222 static void
1223 file_dtor(void *arg, void *obj)
1224 {
1225 file_t *fp = obj;
1226
1227 mutex_enter(&filelist_lock);
1228 nfiles--;
1229 LIST_REMOVE(fp, f_list);
1230 mutex_exit(&filelist_lock);
1231
1232 KASSERT(fp->f_count == 0);
1233 kauth_cred_free(fp->f_cred);
1234 mutex_destroy(&fp->f_lock);
1235 }
1236
1237 static int
1238 fdfile_ctor(void *arg, void *obj, int flags)
1239 {
1240 fdfile_t *ff = obj;
1241
1242 memset(ff, 0, sizeof(*ff));
1243 cv_init(&ff->ff_closing, "fdclose");
1244
1245 return 0;
1246 }
1247
1248 static void
1249 fdfile_dtor(void *arg, void *obj)
1250 {
1251 fdfile_t *ff = obj;
1252
1253 cv_destroy(&ff->ff_closing);
1254 }
1255
1256 file_t *
1257 fgetdummy(void)
1258 {
1259 file_t *fp;
1260
1261 fp = kmem_zalloc(sizeof(*fp), KM_SLEEP);
1262 mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE);
1263 return fp;
1264 }
1265
1266 void
1267 fputdummy(file_t *fp)
1268 {
1269
1270 mutex_destroy(&fp->f_lock);
1271 kmem_free(fp, sizeof(*fp));
1272 }
1273
1274 /*
1275 * Create an initial filedesc structure.
1276 */
1277 filedesc_t *
1278 fd_init(filedesc_t *fdp)
1279 {
1280 #ifdef DIAGNOSTIC
1281 unsigned fd;
1282 #endif
1283
1284 if (__predict_true(fdp == NULL)) {
1285 fdp = pool_cache_get(filedesc_cache, PR_WAITOK);
1286 } else {
1287 KASSERT(fdp == &filedesc0);
1288 filedesc_ctor(NULL, fdp, PR_WAITOK);
1289 }
1290
1291 #ifdef DIAGNOSTIC
1292 KASSERT(fdp->fd_lastfile == -1);
1293 KASSERT(fdp->fd_lastkqfile == -1);
1294 KASSERT(fdp->fd_knhash == NULL);
1295 KASSERT(fdp->fd_freefile == 0);
1296 KASSERT(fdp->fd_exclose == false);
1297 KASSERT(fdp->fd_dt == &fdp->fd_dtbuiltin);
1298 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE);
1299 for (fd = 0; fd < NDFDFILE; fd++) {
1300 KASSERT(fdp->fd_dtbuiltin.dt_ff[fd] ==
1301 (fdfile_t *)fdp->fd_dfdfile[fd]);
1302 }
1303 for (fd = NDFDFILE; fd < NDFILE; fd++) {
1304 KASSERT(fdp->fd_dtbuiltin.dt_ff[fd] == NULL);
1305 }
1306 KASSERT(fdp->fd_himap == fdp->fd_dhimap);
1307 KASSERT(fdp->fd_lomap == fdp->fd_dlomap);
1308 #endif /* DIAGNOSTIC */
1309
1310 fdp->fd_refcnt = 1;
1311 fd_checkmaps(fdp);
1312
1313 return fdp;
1314 }
1315
1316 /*
1317 * Initialize a file descriptor table.
1318 */
1319 static int
1320 filedesc_ctor(void *arg, void *obj, int flag)
1321 {
1322 filedesc_t *fdp = obj;
1323 fdfile_t **ffp;
1324 int i;
1325
1326 memset(fdp, 0, sizeof(*fdp));
1327 mutex_init(&fdp->fd_lock, MUTEX_DEFAULT, IPL_NONE);
1328 fdp->fd_lastfile = -1;
1329 fdp->fd_lastkqfile = -1;
1330 fdp->fd_dt = &fdp->fd_dtbuiltin;
1331 fdp->fd_dtbuiltin.dt_nfiles = NDFILE;
1332 fdp->fd_himap = fdp->fd_dhimap;
1333 fdp->fd_lomap = fdp->fd_dlomap;
1334
1335 CTASSERT(sizeof(fdp->fd_dfdfile[0]) >= sizeof(fdfile_t));
1336 for (i = 0, ffp = fdp->fd_dt->dt_ff; i < NDFDFILE; i++, ffp++) {
1337 *ffp = (fdfile_t *)fdp->fd_dfdfile[i];
1338 (void)fdfile_ctor(NULL, fdp->fd_dfdfile[i], PR_WAITOK);
1339 }
1340
1341 return 0;
1342 }
1343
1344 static void
1345 filedesc_dtor(void *arg, void *obj)
1346 {
1347 filedesc_t *fdp = obj;
1348 int i;
1349
1350 for (i = 0; i < NDFDFILE; i++) {
1351 fdfile_dtor(NULL, fdp->fd_dfdfile[i]);
1352 }
1353
1354 mutex_destroy(&fdp->fd_lock);
1355 }
1356
1357 /*
1358 * Make p share curproc's filedesc structure.
1359 */
1360 void
1361 fd_share(struct proc *p)
1362 {
1363 filedesc_t *fdp;
1364
1365 fdp = curlwp->l_fd;
1366 p->p_fd = fdp;
1367 atomic_inc_uint(&fdp->fd_refcnt);
1368 }
1369
1370 /*
1371 * Acquire a hold on a filedesc structure.
1372 */
1373 void
1374 fd_hold(lwp_t *l)
1375 {
1376 filedesc_t *fdp = l->l_fd;
1377
1378 atomic_inc_uint(&fdp->fd_refcnt);
1379 }
1380
1381 /*
1382 * Copy a filedesc structure.
1383 */
1384 filedesc_t *
1385 fd_copy(void)
1386 {
1387 filedesc_t *newfdp, *fdp;
1388 fdfile_t *ff, **ffp, **nffp, *ff2;
1389 int i, j, numfiles, lastfile, newlast;
1390 file_t *fp;
1391 fdtab_t *newdt;
1392
1393 fdp = curproc->p_fd;
1394 newfdp = pool_cache_get(filedesc_cache, PR_WAITOK);
1395 newfdp->fd_refcnt = 1;
1396
1397 #ifdef DIAGNOSTIC
1398 KASSERT(newfdp->fd_lastfile == -1);
1399 KASSERT(newfdp->fd_lastkqfile == -1);
1400 KASSERT(newfdp->fd_knhash == NULL);
1401 KASSERT(newfdp->fd_freefile == 0);
1402 KASSERT(newfdp->fd_exclose == false);
1403 KASSERT(newfdp->fd_dt == &newfdp->fd_dtbuiltin);
1404 KASSERT(newfdp->fd_dtbuiltin.dt_nfiles == NDFILE);
1405 for (i = 0; i < NDFDFILE; i++) {
1406 KASSERT(newfdp->fd_dtbuiltin.dt_ff[i] ==
1407 (fdfile_t *)&newfdp->fd_dfdfile[i]);
1408 }
1409 for (i = NDFDFILE; i < NDFILE; i++) {
1410 KASSERT(newfdp->fd_dtbuiltin.dt_ff[i] == NULL);
1411 }
1412 #endif /* DIAGNOSTIC */
1413
1414 mutex_enter(&fdp->fd_lock);
1415 fd_checkmaps(fdp);
1416 numfiles = fdp->fd_dt->dt_nfiles;
1417 lastfile = fdp->fd_lastfile;
1418
1419 /*
1420 * If the number of open files fits in the internal arrays
1421 * of the open file structure, use them, otherwise allocate
1422 * additional memory for the number of descriptors currently
1423 * in use.
1424 */
1425 if (lastfile < NDFILE) {
1426 i = NDFILE;
1427 newdt = newfdp->fd_dt;
1428 KASSERT(newfdp->fd_dt == &newfdp->fd_dtbuiltin);
1429 } else {
1430 /*
1431 * Compute the smallest multiple of NDEXTENT needed
1432 * for the file descriptors currently in use,
1433 * allowing the table to shrink.
1434 */
1435 i = numfiles;
1436 while (i >= 2 * NDEXTENT && i > lastfile * 2) {
1437 i /= 2;
1438 }
1439 KASSERT(i > NDFILE);
1440 newdt = fd_dtab_alloc(i);
1441 newfdp->fd_dt = newdt;
1442 memcpy(newdt->dt_ff, newfdp->fd_dtbuiltin.dt_ff,
1443 NDFDFILE * sizeof(fdfile_t **));
1444 memset(newdt->dt_ff + NDFDFILE, 0,
1445 (i - NDFDFILE) * sizeof(fdfile_t **));
1446 }
1447 if (NDHISLOTS(i) <= NDHISLOTS(NDFILE)) {
1448 newfdp->fd_himap = newfdp->fd_dhimap;
1449 newfdp->fd_lomap = newfdp->fd_dlomap;
1450 } else {
1451 fd_map_alloc(i, &newfdp->fd_lomap, &newfdp->fd_himap);
1452 KASSERT(i >= NDENTRIES * NDENTRIES);
1453 memset(newfdp->fd_himap, 0, NDHISLOTS(i)*sizeof(uint32_t));
1454 memset(newfdp->fd_lomap, 0, NDLOSLOTS(i)*sizeof(uint32_t));
1455 }
1456 newfdp->fd_freefile = fdp->fd_freefile;
1457 newfdp->fd_exclose = fdp->fd_exclose;
1458
1459 ffp = fdp->fd_dt->dt_ff;
1460 nffp = newdt->dt_ff;
1461 newlast = -1;
1462 for (i = 0; i <= lastfile; i++, ffp++, nffp++) {
1463 KASSERT(i >= NDFDFILE ||
1464 *nffp == (fdfile_t *)newfdp->fd_dfdfile[i]);
1465 ff = *ffp;
1466 if (ff == NULL ||
1467 (fp = atomic_load_consume(&ff->ff_file)) == NULL) {
1468 /* Descriptor unused, or descriptor half open. */
1469 KASSERT(!fd_isused(newfdp, i));
1470 continue;
1471 }
1472 if (__predict_false(fp->f_type == DTYPE_KQUEUE)) {
1473 /* kqueue descriptors cannot be copied. */
1474 if (i < newfdp->fd_freefile) {
1475 newfdp->fd_freefile = i;
1476 }
1477 continue;
1478 }
1479 /* It's active: add a reference to the file. */
1480 mutex_enter(&fp->f_lock);
1481 fp->f_count++;
1482 mutex_exit(&fp->f_lock);
1483
1484 /* Allocate an fdfile_t to represent it. */
1485 if (i >= NDFDFILE) {
1486 ff2 = pool_cache_get(fdfile_cache, PR_WAITOK);
1487 *nffp = ff2;
1488 } else {
1489 ff2 = newdt->dt_ff[i];
1490 }
1491 ff2->ff_file = fp;
1492 ff2->ff_exclose = ff->ff_exclose;
1493 ff2->ff_allocated = true;
1494
1495 /* Fix up bitmaps. */
1496 j = i >> NDENTRYSHIFT;
1497 KASSERT((newfdp->fd_lomap[j] & (1U << (i & NDENTRYMASK))) == 0);
1498 newfdp->fd_lomap[j] |= 1U << (i & NDENTRYMASK);
1499 if (__predict_false(newfdp->fd_lomap[j] == ~0)) {
1500 KASSERT((newfdp->fd_himap[j >> NDENTRYSHIFT] &
1501 (1U << (j & NDENTRYMASK))) == 0);
1502 newfdp->fd_himap[j >> NDENTRYSHIFT] |=
1503 1U << (j & NDENTRYMASK);
1504 }
1505 newlast = i;
1506 }
1507 KASSERT(newdt->dt_ff[0] == (fdfile_t *)newfdp->fd_dfdfile[0]);
1508 newfdp->fd_lastfile = newlast;
1509 fd_checkmaps(newfdp);
1510 mutex_exit(&fdp->fd_lock);
1511
1512 return newfdp;
1513 }
1514
1515 /*
1516 * Release a filedesc structure.
1517 */
1518 void
1519 fd_free(void)
1520 {
1521 fdfile_t *ff;
1522 file_t *fp;
1523 int fd, nf;
1524 fdtab_t *dt;
1525 lwp_t * const l = curlwp;
1526 filedesc_t * const fdp = l->l_fd;
1527 const bool noadvlock = (l->l_proc->p_flag & PK_ADVLOCK) == 0;
1528
1529 KASSERT(atomic_load_consume(&fdp->fd_dt)->dt_ff[0] ==
1530 (fdfile_t *)fdp->fd_dfdfile[0]);
1531 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE);
1532 KASSERT(fdp->fd_dtbuiltin.dt_link == NULL);
1533
1534 #ifndef __HAVE_ATOMIC_AS_MEMBAR
1535 membar_exit();
1536 #endif
1537 if (atomic_dec_uint_nv(&fdp->fd_refcnt) > 0)
1538 return;
1539
1540 /*
1541 * Close any files that the process holds open.
1542 */
1543 dt = fdp->fd_dt;
1544 fd_checkmaps(fdp);
1545 #ifdef DEBUG
1546 fdp->fd_refcnt = -1; /* see fd_checkmaps */
1547 #endif
1548 for (fd = 0, nf = dt->dt_nfiles; fd < nf; fd++) {
1549 ff = dt->dt_ff[fd];
1550 KASSERT(fd >= NDFDFILE ||
1551 ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
1552 if (ff == NULL)
1553 continue;
1554 if ((fp = atomic_load_consume(&ff->ff_file)) != NULL) {
1555 /*
1556 * Must use fd_close() here if there is
1557 * a reference from kqueue or we might have posix
1558 * advisory locks.
1559 */
1560 if (__predict_true(ff->ff_refcnt == 0) &&
1561 (noadvlock || fp->f_type != DTYPE_VNODE)) {
1562 ff->ff_file = NULL;
1563 ff->ff_exclose = false;
1564 ff->ff_allocated = false;
1565 closef(fp);
1566 } else {
1567 ff->ff_refcnt++;
1568 fd_close(fd);
1569 }
1570 }
1571 KASSERT(ff->ff_refcnt == 0);
1572 KASSERT(ff->ff_file == NULL);
1573 KASSERT(!ff->ff_exclose);
1574 KASSERT(!ff->ff_allocated);
1575 if (fd >= NDFDFILE) {
1576 pool_cache_put(fdfile_cache, ff);
1577 dt->dt_ff[fd] = NULL;
1578 }
1579 }
1580
1581 /*
1582 * Clean out the descriptor table for the next user and return
1583 * to the cache.
1584 */
1585 if (__predict_false(dt != &fdp->fd_dtbuiltin)) {
1586 fd_dtab_free(fdp->fd_dt);
1587 /* Otherwise, done above. */
1588 memset(&fdp->fd_dtbuiltin.dt_ff[NDFDFILE], 0,
1589 (NDFILE - NDFDFILE) * sizeof(fdp->fd_dtbuiltin.dt_ff[0]));
1590 fdp->fd_dt = &fdp->fd_dtbuiltin;
1591 }
1592 if (__predict_false(NDHISLOTS(nf) > NDHISLOTS(NDFILE))) {
1593 KASSERT(fdp->fd_himap != fdp->fd_dhimap);
1594 KASSERT(fdp->fd_lomap != fdp->fd_dlomap);
1595 fd_map_free(nf, fdp->fd_lomap, fdp->fd_himap);
1596 }
1597 if (__predict_false(fdp->fd_knhash != NULL)) {
1598 hashdone(fdp->fd_knhash, HASH_LIST, fdp->fd_knhashmask);
1599 fdp->fd_knhash = NULL;
1600 fdp->fd_knhashmask = 0;
1601 } else {
1602 KASSERT(fdp->fd_knhashmask == 0);
1603 }
1604 fdp->fd_dt = &fdp->fd_dtbuiltin;
1605 fdp->fd_lastkqfile = -1;
1606 fdp->fd_lastfile = -1;
1607 fdp->fd_freefile = 0;
1608 fdp->fd_exclose = false;
1609 memset(&fdp->fd_startzero, 0, sizeof(*fdp) -
1610 offsetof(filedesc_t, fd_startzero));
1611 fdp->fd_himap = fdp->fd_dhimap;
1612 fdp->fd_lomap = fdp->fd_dlomap;
1613 KASSERT(fdp->fd_dtbuiltin.dt_nfiles == NDFILE);
1614 KASSERT(fdp->fd_dtbuiltin.dt_link == NULL);
1615 KASSERT(fdp->fd_dt == &fdp->fd_dtbuiltin);
1616 #ifdef DEBUG
1617 fdp->fd_refcnt = 0; /* see fd_checkmaps */
1618 #endif
1619 fd_checkmaps(fdp);
1620 pool_cache_put(filedesc_cache, fdp);
1621 }
1622
1623 /*
1624 * File Descriptor pseudo-device driver (/dev/fd/).
1625 *
1626 * Opening minor device N dup()s the file (if any) connected to file
1627 * descriptor N belonging to the calling process. Note that this driver
1628 * consists of only the ``open()'' routine, because all subsequent
1629 * references to this file will be direct to the other driver.
1630 */
1631 static int
1632 filedescopen(dev_t dev, int mode, int type, lwp_t *l)
1633 {
1634
1635 /*
1636 * XXX Kludge: set dupfd to contain the value of the
1637 * the file descriptor being sought for duplication. The error
1638 * return ensures that the vnode for this device will be released
1639 * by vn_open. Open will detect this special error and take the
1640 * actions in fd_dupopen below. Other callers of vn_open or VOP_OPEN
1641 * will simply report the error.
1642 */
1643 l->l_dupfd = minor(dev); /* XXX */
1644 return EDUPFD;
1645 }
1646
1647 /*
1648 * Duplicate the specified descriptor to a free descriptor.
1649 *
1650 * old is the original fd.
1651 * moveit is true if we should move rather than duplicate.
1652 * flags are the open flags (converted from O_* to F*).
1653 * newp returns the new fd on success.
1654 *
1655 * These two cases are produced by the EDUPFD and EMOVEFD magic
1656 * errnos, but in the interest of removing that regrettable interface,
1657 * vn_open has been changed to intercept them. Now vn_open returns
1658 * either a vnode or a filehandle, and the filehandle is accompanied
1659 * by a boolean that says whether we should dup (moveit == false) or
1660 * move (moveit == true) the fd.
1661 *
1662 * The dup case is used by /dev/stderr, /proc/self/fd, and such. The
1663 * move case is used by cloner devices that allocate a fd of their
1664 * own (a layering violation that should go away eventually) that
1665 * then needs to be put in the place open() expects it.
1666 */
1667 int
1668 fd_dupopen(int old, bool moveit, int flags, int *newp)
1669 {
1670 filedesc_t *fdp;
1671 fdfile_t *ff;
1672 file_t *fp;
1673 fdtab_t *dt;
1674 int error;
1675
1676 if ((fp = fd_getfile(old)) == NULL) {
1677 return EBADF;
1678 }
1679 fdp = curlwp->l_fd;
1680 dt = atomic_load_consume(&fdp->fd_dt);
1681 ff = dt->dt_ff[old];
1682
1683 /*
1684 * There are two cases of interest here.
1685 *
1686 * 1. moveit == false (used to be the EDUPFD magic errno):
1687 * simply dup (old) to file descriptor (new) and return.
1688 *
1689 * 2. moveit == true (used to be the EMOVEFD magic errno):
1690 * steal away the file structure from (old) and store it in
1691 * (new). (old) is effectively closed by this operation.
1692 */
1693 if (moveit == false) {
1694 /*
1695 * Check that the mode the file is being opened for is a
1696 * subset of the mode of the existing descriptor.
1697 */
1698 if (((flags & (FREAD|FWRITE)) | fp->f_flag) != fp->f_flag) {
1699 error = EACCES;
1700 goto out;
1701 }
1702
1703 /* Copy it. */
1704 error = fd_dup(fp, 0, newp, ff->ff_exclose);
1705 } else {
1706 /* Copy it. */
1707 error = fd_dup(fp, 0, newp, ff->ff_exclose);
1708 if (error != 0) {
1709 goto out;
1710 }
1711
1712 /* Steal away the file pointer from 'old'. */
1713 (void)fd_close(old);
1714 return 0;
1715 }
1716
1717 out:
1718 fd_putfile(old);
1719 return error;
1720 }
1721
1722 /*
1723 * Close open files on exec.
1724 */
1725 void
1726 fd_closeexec(void)
1727 {
1728 proc_t *p;
1729 filedesc_t *fdp;
1730 fdfile_t *ff;
1731 lwp_t *l;
1732 fdtab_t *dt;
1733 int fd;
1734
1735 l = curlwp;
1736 p = l->l_proc;
1737 fdp = p->p_fd;
1738
1739 if (fdp->fd_refcnt > 1) {
1740 fdp = fd_copy();
1741 fd_free();
1742 p->p_fd = fdp;
1743 l->l_fd = fdp;
1744 }
1745 if (!fdp->fd_exclose) {
1746 return;
1747 }
1748 fdp->fd_exclose = false;
1749 dt = atomic_load_consume(&fdp->fd_dt);
1750
1751 for (fd = 0; fd <= fdp->fd_lastfile; fd++) {
1752 if ((ff = dt->dt_ff[fd]) == NULL) {
1753 KASSERT(fd >= NDFDFILE);
1754 continue;
1755 }
1756 KASSERT(fd >= NDFDFILE ||
1757 ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
1758 if (ff->ff_file == NULL)
1759 continue;
1760 if (ff->ff_exclose) {
1761 /*
1762 * We need a reference to close the file.
1763 * No other threads can see the fdfile_t at
1764 * this point, so don't bother locking.
1765 */
1766 KASSERT((ff->ff_refcnt & FR_CLOSING) == 0);
1767 ff->ff_refcnt++;
1768 fd_close(fd);
1769 }
1770 }
1771 }
1772
1773 /*
1774 * Sets descriptor owner. If the owner is a process, 'pgid'
1775 * is set to positive value, process ID. If the owner is process group,
1776 * 'pgid' is set to -pg_id.
1777 */
1778 int
1779 fsetown(pid_t *pgid, u_long cmd, const void *data)
1780 {
1781 pid_t id = *(const pid_t *)data;
1782 int error;
1783
1784 if (id == INT_MIN)
1785 return EINVAL;
1786
1787 switch (cmd) {
1788 case TIOCSPGRP:
1789 if (id < 0)
1790 return EINVAL;
1791 id = -id;
1792 break;
1793 default:
1794 break;
1795 }
1796 if (id > 0) {
1797 mutex_enter(&proc_lock);
1798 error = proc_find(id) ? 0 : ESRCH;
1799 mutex_exit(&proc_lock);
1800 } else if (id < 0) {
1801 error = pgid_in_session(curproc, -id);
1802 } else {
1803 error = 0;
1804 }
1805 if (!error) {
1806 *pgid = id;
1807 }
1808 return error;
1809 }
1810
1811 void
1812 fd_set_exclose(struct lwp *l, int fd, bool exclose)
1813 {
1814 filedesc_t *fdp = l->l_fd;
1815 fdfile_t *ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd];
1816
1817 ff->ff_exclose = exclose;
1818 if (exclose)
1819 fdp->fd_exclose = true;
1820 }
1821
1822 /*
1823 * Return descriptor owner information. If the value is positive,
1824 * it's process ID. If it's negative, it's process group ID and
1825 * needs the sign removed before use.
1826 */
1827 int
1828 fgetown(pid_t pgid, u_long cmd, void *data)
1829 {
1830
1831 switch (cmd) {
1832 case TIOCGPGRP:
1833 *(int *)data = -pgid;
1834 break;
1835 default:
1836 *(int *)data = pgid;
1837 break;
1838 }
1839 return 0;
1840 }
1841
1842 /*
1843 * Send signal to descriptor owner, either process or process group.
1844 */
1845 void
1846 fownsignal(pid_t pgid, int signo, int code, int band, void *fdescdata)
1847 {
1848 ksiginfo_t ksi;
1849
1850 KASSERT(!cpu_intr_p());
1851
1852 if (pgid == 0) {
1853 return;
1854 }
1855
1856 KSI_INIT(&ksi);
1857 ksi.ksi_signo = signo;
1858 ksi.ksi_code = code;
1859 ksi.ksi_band = band;
1860
1861 mutex_enter(&proc_lock);
1862 if (pgid > 0) {
1863 struct proc *p1;
1864
1865 p1 = proc_find(pgid);
1866 if (p1 != NULL) {
1867 kpsignal(p1, &ksi, fdescdata);
1868 }
1869 } else {
1870 struct pgrp *pgrp;
1871
1872 KASSERT(pgid < 0);
1873 pgrp = pgrp_find(-pgid);
1874 if (pgrp != NULL) {
1875 kpgsignal(pgrp, &ksi, fdescdata, 0);
1876 }
1877 }
1878 mutex_exit(&proc_lock);
1879 }
1880
1881 int
1882 fd_clone(file_t *fp, unsigned fd, int flag, const struct fileops *fops,
1883 void *data)
1884 {
1885 fdfile_t *ff;
1886 filedesc_t *fdp;
1887
1888 fp->f_flag = flag & FMASK;
1889 fdp = curproc->p_fd;
1890 ff = atomic_load_consume(&fdp->fd_dt)->dt_ff[fd];
1891 KASSERT(ff != NULL);
1892 ff->ff_exclose = (flag & O_CLOEXEC) != 0;
1893 fp->f_type = DTYPE_MISC;
1894 fp->f_ops = fops;
1895 fp->f_data = data;
1896 curlwp->l_dupfd = fd;
1897 fd_affix(curproc, fp, fd);
1898
1899 return EMOVEFD;
1900 }
1901
1902 int
1903 fnullop_fcntl(file_t *fp, u_int cmd, void *data)
1904 {
1905
1906 if (cmd == F_SETFL)
1907 return 0;
1908
1909 return EOPNOTSUPP;
1910 }
1911
1912 int
1913 fnullop_poll(file_t *fp, int which)
1914 {
1915
1916 return 0;
1917 }
1918
1919 int
1920 fnullop_kqfilter(file_t *fp, struct knote *kn)
1921 {
1922
1923 return EOPNOTSUPP;
1924 }
1925
1926 void
1927 fnullop_restart(file_t *fp)
1928 {
1929
1930 }
1931
1932 int
1933 fbadop_read(file_t *fp, off_t *offset, struct uio *uio,
1934 kauth_cred_t cred, int flags)
1935 {
1936
1937 return EOPNOTSUPP;
1938 }
1939
1940 int
1941 fbadop_write(file_t *fp, off_t *offset, struct uio *uio,
1942 kauth_cred_t cred, int flags)
1943 {
1944
1945 return EOPNOTSUPP;
1946 }
1947
1948 int
1949 fbadop_ioctl(file_t *fp, u_long com, void *data)
1950 {
1951
1952 return EOPNOTSUPP;
1953 }
1954
1955 int
1956 fbadop_stat(file_t *fp, struct stat *sb)
1957 {
1958
1959 return EOPNOTSUPP;
1960 }
1961
1962 int
1963 fbadop_close(file_t *fp)
1964 {
1965
1966 return EOPNOTSUPP;
1967 }
1968
1969 /*
1970 * sysctl routines pertaining to file descriptors
1971 */
1972
1973 /* Initialized in sysctl_init() for now... */
1974 extern kmutex_t sysctl_file_marker_lock;
1975 static u_int sysctl_file_marker = 1;
1976
1977 /*
1978 * Expects to be called with proc_lock and sysctl_file_marker_lock locked.
1979 */
1980 static void
1981 sysctl_file_marker_reset(void)
1982 {
1983 struct proc *p;
1984
1985 PROCLIST_FOREACH(p, &allproc) {
1986 struct filedesc *fd = p->p_fd;
1987 fdtab_t *dt;
1988 u_int i;
1989
1990 mutex_enter(&fd->fd_lock);
1991 dt = fd->fd_dt;
1992 for (i = 0; i < dt->dt_nfiles; i++) {
1993 struct file *fp;
1994 fdfile_t *ff;
1995
1996 if ((ff = dt->dt_ff[i]) == NULL) {
1997 continue;
1998 }
1999 if ((fp = atomic_load_consume(&ff->ff_file)) == NULL) {
2000 continue;
2001 }
2002 fp->f_marker = 0;
2003 }
2004 mutex_exit(&fd->fd_lock);
2005 }
2006 }
2007
2008 /*
2009 * sysctl helper routine for kern.file pseudo-subtree.
2010 */
2011 static int
2012 sysctl_kern_file(SYSCTLFN_ARGS)
2013 {
2014 const bool allowaddr = get_expose_address(curproc);
2015 struct filelist flist;
2016 int error;
2017 size_t buflen;
2018 struct file *fp, fbuf;
2019 char *start, *where;
2020 struct proc *p;
2021
2022 start = where = oldp;
2023 buflen = *oldlenp;
2024
2025 if (where == NULL) {
2026 /*
2027 * overestimate by 10 files
2028 */
2029 *oldlenp = sizeof(filehead) + (nfiles + 10) *
2030 sizeof(struct file);
2031 return 0;
2032 }
2033
2034 /*
2035 * first sysctl_copyout filehead
2036 */
2037 if (buflen < sizeof(filehead)) {
2038 *oldlenp = 0;
2039 return 0;
2040 }
2041 sysctl_unlock();
2042 if (allowaddr) {
2043 memcpy(&flist, &filehead, sizeof(flist));
2044 } else {
2045 memset(&flist, 0, sizeof(flist));
2046 }
2047 error = sysctl_copyout(l, &flist, where, sizeof(flist));
2048 if (error) {
2049 sysctl_relock();
2050 return error;
2051 }
2052 buflen -= sizeof(flist);
2053 where += sizeof(flist);
2054
2055 /*
2056 * followed by an array of file structures
2057 */
2058 mutex_enter(&sysctl_file_marker_lock);
2059 mutex_enter(&proc_lock);
2060 PROCLIST_FOREACH(p, &allproc) {
2061 struct filedesc *fd;
2062 fdtab_t *dt;
2063 u_int i;
2064
2065 if (p->p_stat == SIDL) {
2066 /* skip embryonic processes */
2067 continue;
2068 }
2069 mutex_enter(p->p_lock);
2070 error = kauth_authorize_process(l->l_cred,
2071 KAUTH_PROCESS_CANSEE, p,
2072 KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_OPENFILES),
2073 NULL, NULL);
2074 mutex_exit(p->p_lock);
2075 if (error != 0) {
2076 /*
2077 * Don't leak kauth retval if we're silently
2078 * skipping this entry.
2079 */
2080 error = 0;
2081 continue;
2082 }
2083
2084 /*
2085 * Grab a hold on the process.
2086 */
2087 if (!rw_tryenter(&p->p_reflock, RW_READER)) {
2088 continue;
2089 }
2090 mutex_exit(&proc_lock);
2091
2092 fd = p->p_fd;
2093 mutex_enter(&fd->fd_lock);
2094 dt = fd->fd_dt;
2095 for (i = 0; i < dt->dt_nfiles; i++) {
2096 fdfile_t *ff;
2097
2098 if ((ff = dt->dt_ff[i]) == NULL) {
2099 continue;
2100 }
2101 if ((fp = atomic_load_consume(&ff->ff_file)) == NULL) {
2102 continue;
2103 }
2104
2105 mutex_enter(&fp->f_lock);
2106
2107 if ((fp->f_count == 0) ||
2108 (fp->f_marker == sysctl_file_marker)) {
2109 mutex_exit(&fp->f_lock);
2110 continue;
2111 }
2112
2113 /* Check that we have enough space. */
2114 if (buflen < sizeof(struct file)) {
2115 *oldlenp = where - start;
2116 mutex_exit(&fp->f_lock);
2117 error = ENOMEM;
2118 break;
2119 }
2120
2121 fill_file(&fbuf, fp);
2122 mutex_exit(&fp->f_lock);
2123 error = sysctl_copyout(l, &fbuf, where, sizeof(fbuf));
2124 if (error) {
2125 break;
2126 }
2127 buflen -= sizeof(struct file);
2128 where += sizeof(struct file);
2129
2130 fp->f_marker = sysctl_file_marker;
2131 }
2132 mutex_exit(&fd->fd_lock);
2133
2134 /*
2135 * Release reference to process.
2136 */
2137 mutex_enter(&proc_lock);
2138 rw_exit(&p->p_reflock);
2139
2140 if (error)
2141 break;
2142 }
2143
2144 sysctl_file_marker++;
2145 /* Reset all markers if wrapped. */
2146 if (sysctl_file_marker == 0) {
2147 sysctl_file_marker_reset();
2148 sysctl_file_marker++;
2149 }
2150
2151 mutex_exit(&proc_lock);
2152 mutex_exit(&sysctl_file_marker_lock);
2153
2154 *oldlenp = where - start;
2155 sysctl_relock();
2156 return error;
2157 }
2158
2159 /*
2160 * sysctl helper function for kern.file2
2161 */
2162 static int
2163 sysctl_kern_file2(SYSCTLFN_ARGS)
2164 {
2165 struct proc *p;
2166 struct file *fp;
2167 struct filedesc *fd;
2168 struct kinfo_file kf;
2169 char *dp;
2170 u_int i, op;
2171 size_t len, needed, elem_size, out_size;
2172 int error, arg, elem_count;
2173 fdfile_t *ff;
2174 fdtab_t *dt;
2175
2176 if (namelen == 1 && name[0] == CTL_QUERY)
2177 return sysctl_query(SYSCTLFN_CALL(rnode));
2178
2179 if (namelen != 4)
2180 return EINVAL;
2181
2182 error = 0;
2183 dp = oldp;
2184 len = (oldp != NULL) ? *oldlenp : 0;
2185 op = name[0];
2186 arg = name[1];
2187 elem_size = name[2];
2188 elem_count = name[3];
2189 out_size = MIN(sizeof(kf), elem_size);
2190 needed = 0;
2191
2192 if (elem_size < 1 || elem_count < 0)
2193 return EINVAL;
2194
2195 switch (op) {
2196 case KERN_FILE_BYFILE:
2197 case KERN_FILE_BYPID:
2198 /*
2199 * We're traversing the process list in both cases; the BYFILE
2200 * case does additional work of keeping track of files already
2201 * looked at.
2202 */
2203
2204 /* doesn't use arg so it must be zero */
2205 if ((op == KERN_FILE_BYFILE) && (arg != 0))
2206 return EINVAL;
2207
2208 if ((op == KERN_FILE_BYPID) && (arg < -1))
2209 /* -1 means all processes */
2210 return EINVAL;
2211
2212 sysctl_unlock();
2213 if (op == KERN_FILE_BYFILE)
2214 mutex_enter(&sysctl_file_marker_lock);
2215 mutex_enter(&proc_lock);
2216 PROCLIST_FOREACH(p, &allproc) {
2217 if (p->p_stat == SIDL) {
2218 /* skip embryonic processes */
2219 continue;
2220 }
2221 if (arg > 0 && p->p_pid != arg) {
2222 /* pick only the one we want */
2223 /* XXX want 0 to mean "kernel files" */
2224 continue;
2225 }
2226 mutex_enter(p->p_lock);
2227 error = kauth_authorize_process(l->l_cred,
2228 KAUTH_PROCESS_CANSEE, p,
2229 KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_OPENFILES),
2230 NULL, NULL);
2231 mutex_exit(p->p_lock);
2232 if (error != 0) {
2233 /*
2234 * Don't leak kauth retval if we're silently
2235 * skipping this entry.
2236 */
2237 error = 0;
2238 continue;
2239 }
2240
2241 /*
2242 * Grab a hold on the process.
2243 */
2244 if (!rw_tryenter(&p->p_reflock, RW_READER)) {
2245 continue;
2246 }
2247 mutex_exit(&proc_lock);
2248
2249 fd = p->p_fd;
2250 mutex_enter(&fd->fd_lock);
2251 dt = fd->fd_dt;
2252 for (i = 0; i < dt->dt_nfiles; i++) {
2253 if ((ff = dt->dt_ff[i]) == NULL) {
2254 continue;
2255 }
2256 if ((fp = atomic_load_consume(&ff->ff_file)) ==
2257 NULL) {
2258 continue;
2259 }
2260
2261 if ((op == KERN_FILE_BYFILE) &&
2262 (fp->f_marker == sysctl_file_marker)) {
2263 continue;
2264 }
2265 if (len >= elem_size && elem_count > 0) {
2266 mutex_enter(&fp->f_lock);
2267 fill_file2(&kf, fp, ff, i, p->p_pid);
2268 mutex_exit(&fp->f_lock);
2269 mutex_exit(&fd->fd_lock);
2270 error = sysctl_copyout(l,
2271 &kf, dp, out_size);
2272 mutex_enter(&fd->fd_lock);
2273 if (error)
2274 break;
2275 dp += elem_size;
2276 len -= elem_size;
2277 }
2278 if (op == KERN_FILE_BYFILE)
2279 fp->f_marker = sysctl_file_marker;
2280 needed += elem_size;
2281 if (elem_count > 0 && elem_count != INT_MAX)
2282 elem_count--;
2283 }
2284 mutex_exit(&fd->fd_lock);
2285
2286 /*
2287 * Release reference to process.
2288 */
2289 mutex_enter(&proc_lock);
2290 rw_exit(&p->p_reflock);
2291 }
2292 if (op == KERN_FILE_BYFILE) {
2293 sysctl_file_marker++;
2294
2295 /* Reset all markers if wrapped. */
2296 if (sysctl_file_marker == 0) {
2297 sysctl_file_marker_reset();
2298 sysctl_file_marker++;
2299 }
2300 }
2301 mutex_exit(&proc_lock);
2302 if (op == KERN_FILE_BYFILE)
2303 mutex_exit(&sysctl_file_marker_lock);
2304 sysctl_relock();
2305 break;
2306 default:
2307 return EINVAL;
2308 }
2309
2310 if (oldp == NULL)
2311 needed += KERN_FILESLOP * elem_size;
2312 *oldlenp = needed;
2313
2314 return error;
2315 }
2316
2317 static void
2318 fill_file(struct file *fp, const struct file *fpsrc)
2319 {
2320 const bool allowaddr = get_expose_address(curproc);
2321
2322 memset(fp, 0, sizeof(*fp));
2323
2324 fp->f_offset = fpsrc->f_offset;
2325 COND_SET_PTR(fp->f_cred, fpsrc->f_cred, allowaddr);
2326 COND_SET_CPTR(fp->f_ops, fpsrc->f_ops, allowaddr);
2327 COND_SET_STRUCT(fp->f_undata, fpsrc->f_undata, allowaddr);
2328 COND_SET_STRUCT(fp->f_list, fpsrc->f_list, allowaddr);
2329 fp->f_flag = fpsrc->f_flag;
2330 fp->f_marker = fpsrc->f_marker;
2331 fp->f_type = fpsrc->f_type;
2332 fp->f_advice = fpsrc->f_advice;
2333 fp->f_count = fpsrc->f_count;
2334 fp->f_msgcount = fpsrc->f_msgcount;
2335 fp->f_unpcount = fpsrc->f_unpcount;
2336 COND_SET_STRUCT(fp->f_unplist, fpsrc->f_unplist, allowaddr);
2337 }
2338
2339 static void
2340 fill_file2(struct kinfo_file *kp, const file_t *fp, const fdfile_t *ff,
2341 int i, pid_t pid)
2342 {
2343 const bool allowaddr = get_expose_address(curproc);
2344
2345 memset(kp, 0, sizeof(*kp));
2346
2347 COND_SET_VALUE(kp->ki_fileaddr, PTRTOUINT64(fp), allowaddr);
2348 kp->ki_flag = fp->f_flag;
2349 kp->ki_iflags = 0;
2350 kp->ki_ftype = fp->f_type;
2351 kp->ki_count = fp->f_count;
2352 kp->ki_msgcount = fp->f_msgcount;
2353 COND_SET_VALUE(kp->ki_fucred, PTRTOUINT64(fp->f_cred), allowaddr);
2354 kp->ki_fuid = kauth_cred_geteuid(fp->f_cred);
2355 kp->ki_fgid = kauth_cred_getegid(fp->f_cred);
2356 COND_SET_VALUE(kp->ki_fops, PTRTOUINT64(fp->f_ops), allowaddr);
2357 kp->ki_foffset = fp->f_offset;
2358 COND_SET_VALUE(kp->ki_fdata, PTRTOUINT64(fp->f_data), allowaddr);
2359
2360 /* vnode information to glue this file to something */
2361 if (fp->f_type == DTYPE_VNODE) {
2362 struct vnode *vp = fp->f_vnode;
2363
2364 COND_SET_VALUE(kp->ki_vun, PTRTOUINT64(vp->v_un.vu_socket),
2365 allowaddr);
2366 kp->ki_vsize = vp->v_size;
2367 kp->ki_vtype = vp->v_type;
2368 kp->ki_vtag = vp->v_tag;
2369 COND_SET_VALUE(kp->ki_vdata, PTRTOUINT64(vp->v_data),
2370 allowaddr);
2371 }
2372
2373 /* process information when retrieved via KERN_FILE_BYPID */
2374 if (ff != NULL) {
2375 kp->ki_pid = pid;
2376 kp->ki_fd = i;
2377 kp->ki_ofileflags = ff->ff_exclose;
2378 kp->ki_usecount = ff->ff_refcnt;
2379 }
2380 }
Cache object: f7ba16fa69d63facd64d9ecb21892e9c
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