1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)sys_generic.c 8.5 (Berkeley) 1/21/94
37 */
38
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41
42 #include "opt_capsicum.h"
43 #include "opt_ktrace.h"
44
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/sysproto.h>
48 #include <sys/capsicum.h>
49 #include <sys/filedesc.h>
50 #include <sys/filio.h>
51 #include <sys/fcntl.h>
52 #include <sys/file.h>
53 #include <sys/lock.h>
54 #include <sys/proc.h>
55 #include <sys/signalvar.h>
56 #include <sys/socketvar.h>
57 #include <sys/uio.h>
58 #include <sys/eventfd.h>
59 #include <sys/kernel.h>
60 #include <sys/ktr.h>
61 #include <sys/limits.h>
62 #include <sys/malloc.h>
63 #include <sys/poll.h>
64 #include <sys/resourcevar.h>
65 #include <sys/selinfo.h>
66 #include <sys/sleepqueue.h>
67 #include <sys/specialfd.h>
68 #include <sys/syscallsubr.h>
69 #include <sys/sysctl.h>
70 #include <sys/sysent.h>
71 #include <sys/vnode.h>
72 #include <sys/bio.h>
73 #include <sys/buf.h>
74 #include <sys/condvar.h>
75 #ifdef KTRACE
76 #include <sys/ktrace.h>
77 #endif
78
79 #include <security/audit/audit.h>
80
81 /*
82 * The following macro defines how many bytes will be allocated from
83 * the stack instead of memory allocated when passing the IOCTL data
84 * structures from userspace and to the kernel. Some IOCTLs having
85 * small data structures are used very frequently and this small
86 * buffer on the stack gives a significant speedup improvement for
87 * those requests. The value of this define should be greater or equal
88 * to 64 bytes and should also be power of two. The data structure is
89 * currently hard-aligned to a 8-byte boundary on the stack. This
90 * should currently be sufficient for all supported platforms.
91 */
92 #define SYS_IOCTL_SMALL_SIZE 128 /* bytes */
93 #define SYS_IOCTL_SMALL_ALIGN 8 /* bytes */
94
95 #ifdef __LP64__
96 static int iosize_max_clamp = 0;
97 SYSCTL_INT(_debug, OID_AUTO, iosize_max_clamp, CTLFLAG_RW,
98 &iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX");
99 static int devfs_iosize_max_clamp = 1;
100 SYSCTL_INT(_debug, OID_AUTO, devfs_iosize_max_clamp, CTLFLAG_RW,
101 &devfs_iosize_max_clamp, 0, "Clamp max i/o size to INT_MAX for devices");
102 #endif
103
104 /*
105 * Assert that the return value of read(2) and write(2) syscalls fits
106 * into a register. If not, an architecture will need to provide the
107 * usermode wrappers to reconstruct the result.
108 */
109 CTASSERT(sizeof(register_t) >= sizeof(size_t));
110
111 static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer");
112 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer");
113 MALLOC_DEFINE(M_IOV, "iov", "large iov's");
114
115 static int pollout(struct thread *, struct pollfd *, struct pollfd *,
116 u_int);
117 static int pollscan(struct thread *, struct pollfd *, u_int);
118 static int pollrescan(struct thread *);
119 static int selscan(struct thread *, fd_mask **, fd_mask **, int);
120 static int selrescan(struct thread *, fd_mask **, fd_mask **);
121 static void selfdalloc(struct thread *, void *);
122 static void selfdfree(struct seltd *, struct selfd *);
123 static int dofileread(struct thread *, int, struct file *, struct uio *,
124 off_t, int);
125 static int dofilewrite(struct thread *, int, struct file *, struct uio *,
126 off_t, int);
127 static void doselwakeup(struct selinfo *, int);
128 static void seltdinit(struct thread *);
129 static int seltdwait(struct thread *, sbintime_t, sbintime_t);
130 static void seltdclear(struct thread *);
131
132 /*
133 * One seltd per-thread allocated on demand as needed.
134 *
135 * t - protected by st_mtx
136 * k - Only accessed by curthread or read-only
137 */
138 struct seltd {
139 STAILQ_HEAD(, selfd) st_selq; /* (k) List of selfds. */
140 struct selfd *st_free1; /* (k) free fd for read set. */
141 struct selfd *st_free2; /* (k) free fd for write set. */
142 struct mtx st_mtx; /* Protects struct seltd */
143 struct cv st_wait; /* (t) Wait channel. */
144 int st_flags; /* (t) SELTD_ flags. */
145 };
146
147 #define SELTD_PENDING 0x0001 /* We have pending events. */
148 #define SELTD_RESCAN 0x0002 /* Doing a rescan. */
149
150 /*
151 * One selfd allocated per-thread per-file-descriptor.
152 * f - protected by sf_mtx
153 */
154 struct selfd {
155 STAILQ_ENTRY(selfd) sf_link; /* (k) fds owned by this td. */
156 TAILQ_ENTRY(selfd) sf_threads; /* (f) fds on this selinfo. */
157 struct selinfo *sf_si; /* (f) selinfo when linked. */
158 struct mtx *sf_mtx; /* Pointer to selinfo mtx. */
159 struct seltd *sf_td; /* (k) owning seltd. */
160 void *sf_cookie; /* (k) fd or pollfd. */
161 };
162
163 MALLOC_DEFINE(M_SELFD, "selfd", "selfd");
164 static struct mtx_pool *mtxpool_select;
165
166 #ifdef __LP64__
167 size_t
168 devfs_iosize_max(void)
169 {
170
171 return (devfs_iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ?
172 INT_MAX : SSIZE_MAX);
173 }
174
175 size_t
176 iosize_max(void)
177 {
178
179 return (iosize_max_clamp || SV_CURPROC_FLAG(SV_ILP32) ?
180 INT_MAX : SSIZE_MAX);
181 }
182 #endif
183
184 #ifndef _SYS_SYSPROTO_H_
185 struct read_args {
186 int fd;
187 void *buf;
188 size_t nbyte;
189 };
190 #endif
191 int
192 sys_read(struct thread *td, struct read_args *uap)
193 {
194 struct uio auio;
195 struct iovec aiov;
196 int error;
197
198 if (uap->nbyte > IOSIZE_MAX)
199 return (EINVAL);
200 aiov.iov_base = uap->buf;
201 aiov.iov_len = uap->nbyte;
202 auio.uio_iov = &aiov;
203 auio.uio_iovcnt = 1;
204 auio.uio_resid = uap->nbyte;
205 auio.uio_segflg = UIO_USERSPACE;
206 error = kern_readv(td, uap->fd, &auio);
207 return (error);
208 }
209
210 /*
211 * Positioned read system call
212 */
213 #ifndef _SYS_SYSPROTO_H_
214 struct pread_args {
215 int fd;
216 void *buf;
217 size_t nbyte;
218 int pad;
219 off_t offset;
220 };
221 #endif
222 int
223 sys_pread(struct thread *td, struct pread_args *uap)
224 {
225
226 return (kern_pread(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
227 }
228
229 int
230 kern_pread(struct thread *td, int fd, void *buf, size_t nbyte, off_t offset)
231 {
232 struct uio auio;
233 struct iovec aiov;
234 int error;
235
236 if (nbyte > IOSIZE_MAX)
237 return (EINVAL);
238 aiov.iov_base = buf;
239 aiov.iov_len = nbyte;
240 auio.uio_iov = &aiov;
241 auio.uio_iovcnt = 1;
242 auio.uio_resid = nbyte;
243 auio.uio_segflg = UIO_USERSPACE;
244 error = kern_preadv(td, fd, &auio, offset);
245 return (error);
246 }
247
248 #if defined(COMPAT_FREEBSD6)
249 int
250 freebsd6_pread(struct thread *td, struct freebsd6_pread_args *uap)
251 {
252
253 return (kern_pread(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
254 }
255 #endif
256
257 /*
258 * Scatter read system call.
259 */
260 #ifndef _SYS_SYSPROTO_H_
261 struct readv_args {
262 int fd;
263 struct iovec *iovp;
264 u_int iovcnt;
265 };
266 #endif
267 int
268 sys_readv(struct thread *td, struct readv_args *uap)
269 {
270 struct uio *auio;
271 int error;
272
273 error = copyinuio(uap->iovp, uap->iovcnt, &auio);
274 if (error)
275 return (error);
276 error = kern_readv(td, uap->fd, auio);
277 free(auio, M_IOV);
278 return (error);
279 }
280
281 int
282 kern_readv(struct thread *td, int fd, struct uio *auio)
283 {
284 struct file *fp;
285 int error;
286
287 error = fget_read(td, fd, &cap_read_rights, &fp);
288 if (error)
289 return (error);
290 error = dofileread(td, fd, fp, auio, (off_t)-1, 0);
291 fdrop(fp, td);
292 return (error);
293 }
294
295 /*
296 * Scatter positioned read system call.
297 */
298 #ifndef _SYS_SYSPROTO_H_
299 struct preadv_args {
300 int fd;
301 struct iovec *iovp;
302 u_int iovcnt;
303 off_t offset;
304 };
305 #endif
306 int
307 sys_preadv(struct thread *td, struct preadv_args *uap)
308 {
309 struct uio *auio;
310 int error;
311
312 error = copyinuio(uap->iovp, uap->iovcnt, &auio);
313 if (error)
314 return (error);
315 error = kern_preadv(td, uap->fd, auio, uap->offset);
316 free(auio, M_IOV);
317 return (error);
318 }
319
320 int
321 kern_preadv(struct thread *td, int fd, struct uio *auio, off_t offset)
322 {
323 struct file *fp;
324 int error;
325
326 error = fget_read(td, fd, &cap_pread_rights, &fp);
327 if (error)
328 return (error);
329 if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
330 error = ESPIPE;
331 else if (offset < 0 &&
332 (fp->f_vnode == NULL || fp->f_vnode->v_type != VCHR))
333 error = EINVAL;
334 else
335 error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET);
336 fdrop(fp, td);
337 return (error);
338 }
339
340 /*
341 * Common code for readv and preadv that reads data in
342 * from a file using the passed in uio, offset, and flags.
343 */
344 static int
345 dofileread(struct thread *td, int fd, struct file *fp, struct uio *auio,
346 off_t offset, int flags)
347 {
348 ssize_t cnt;
349 int error;
350 #ifdef KTRACE
351 struct uio *ktruio = NULL;
352 #endif
353
354 AUDIT_ARG_FD(fd);
355
356 /* Finish zero length reads right here */
357 if (auio->uio_resid == 0) {
358 td->td_retval[0] = 0;
359 return (0);
360 }
361 auio->uio_rw = UIO_READ;
362 auio->uio_offset = offset;
363 auio->uio_td = td;
364 #ifdef KTRACE
365 if (KTRPOINT(td, KTR_GENIO))
366 ktruio = cloneuio(auio);
367 #endif
368 cnt = auio->uio_resid;
369 if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) {
370 if (auio->uio_resid != cnt && (error == ERESTART ||
371 error == EINTR || error == EWOULDBLOCK))
372 error = 0;
373 }
374 cnt -= auio->uio_resid;
375 #ifdef KTRACE
376 if (ktruio != NULL) {
377 ktruio->uio_resid = cnt;
378 ktrgenio(fd, UIO_READ, ktruio, error);
379 }
380 #endif
381 td->td_retval[0] = cnt;
382 return (error);
383 }
384
385 #ifndef _SYS_SYSPROTO_H_
386 struct write_args {
387 int fd;
388 const void *buf;
389 size_t nbyte;
390 };
391 #endif
392 int
393 sys_write(struct thread *td, struct write_args *uap)
394 {
395 struct uio auio;
396 struct iovec aiov;
397 int error;
398
399 if (uap->nbyte > IOSIZE_MAX)
400 return (EINVAL);
401 aiov.iov_base = (void *)(uintptr_t)uap->buf;
402 aiov.iov_len = uap->nbyte;
403 auio.uio_iov = &aiov;
404 auio.uio_iovcnt = 1;
405 auio.uio_resid = uap->nbyte;
406 auio.uio_segflg = UIO_USERSPACE;
407 error = kern_writev(td, uap->fd, &auio);
408 return (error);
409 }
410
411 /*
412 * Positioned write system call.
413 */
414 #ifndef _SYS_SYSPROTO_H_
415 struct pwrite_args {
416 int fd;
417 const void *buf;
418 size_t nbyte;
419 int pad;
420 off_t offset;
421 };
422 #endif
423 int
424 sys_pwrite(struct thread *td, struct pwrite_args *uap)
425 {
426
427 return (kern_pwrite(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
428 }
429
430 int
431 kern_pwrite(struct thread *td, int fd, const void *buf, size_t nbyte,
432 off_t offset)
433 {
434 struct uio auio;
435 struct iovec aiov;
436 int error;
437
438 if (nbyte > IOSIZE_MAX)
439 return (EINVAL);
440 aiov.iov_base = (void *)(uintptr_t)buf;
441 aiov.iov_len = nbyte;
442 auio.uio_iov = &aiov;
443 auio.uio_iovcnt = 1;
444 auio.uio_resid = nbyte;
445 auio.uio_segflg = UIO_USERSPACE;
446 error = kern_pwritev(td, fd, &auio, offset);
447 return (error);
448 }
449
450 #if defined(COMPAT_FREEBSD6)
451 int
452 freebsd6_pwrite(struct thread *td, struct freebsd6_pwrite_args *uap)
453 {
454
455 return (kern_pwrite(td, uap->fd, uap->buf, uap->nbyte, uap->offset));
456 }
457 #endif
458
459 /*
460 * Gather write system call.
461 */
462 #ifndef _SYS_SYSPROTO_H_
463 struct writev_args {
464 int fd;
465 struct iovec *iovp;
466 u_int iovcnt;
467 };
468 #endif
469 int
470 sys_writev(struct thread *td, struct writev_args *uap)
471 {
472 struct uio *auio;
473 int error;
474
475 error = copyinuio(uap->iovp, uap->iovcnt, &auio);
476 if (error)
477 return (error);
478 error = kern_writev(td, uap->fd, auio);
479 free(auio, M_IOV);
480 return (error);
481 }
482
483 int
484 kern_writev(struct thread *td, int fd, struct uio *auio)
485 {
486 struct file *fp;
487 int error;
488
489 error = fget_write(td, fd, &cap_write_rights, &fp);
490 if (error)
491 return (error);
492 error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0);
493 fdrop(fp, td);
494 return (error);
495 }
496
497 /*
498 * Gather positioned write system call.
499 */
500 #ifndef _SYS_SYSPROTO_H_
501 struct pwritev_args {
502 int fd;
503 struct iovec *iovp;
504 u_int iovcnt;
505 off_t offset;
506 };
507 #endif
508 int
509 sys_pwritev(struct thread *td, struct pwritev_args *uap)
510 {
511 struct uio *auio;
512 int error;
513
514 error = copyinuio(uap->iovp, uap->iovcnt, &auio);
515 if (error)
516 return (error);
517 error = kern_pwritev(td, uap->fd, auio, uap->offset);
518 free(auio, M_IOV);
519 return (error);
520 }
521
522 int
523 kern_pwritev(struct thread *td, int fd, struct uio *auio, off_t offset)
524 {
525 struct file *fp;
526 int error;
527
528 error = fget_write(td, fd, &cap_pwrite_rights, &fp);
529 if (error)
530 return (error);
531 if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
532 error = ESPIPE;
533 else if (offset < 0 &&
534 (fp->f_vnode == NULL || fp->f_vnode->v_type != VCHR))
535 error = EINVAL;
536 else
537 error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET);
538 fdrop(fp, td);
539 return (error);
540 }
541
542 /*
543 * Common code for writev and pwritev that writes data to
544 * a file using the passed in uio, offset, and flags.
545 */
546 static int
547 dofilewrite(struct thread *td, int fd, struct file *fp, struct uio *auio,
548 off_t offset, int flags)
549 {
550 ssize_t cnt;
551 int error;
552 #ifdef KTRACE
553 struct uio *ktruio = NULL;
554 #endif
555
556 AUDIT_ARG_FD(fd);
557 auio->uio_rw = UIO_WRITE;
558 auio->uio_td = td;
559 auio->uio_offset = offset;
560 #ifdef KTRACE
561 if (KTRPOINT(td, KTR_GENIO))
562 ktruio = cloneuio(auio);
563 #endif
564 cnt = auio->uio_resid;
565 if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) {
566 if (auio->uio_resid != cnt && (error == ERESTART ||
567 error == EINTR || error == EWOULDBLOCK))
568 error = 0;
569 /* Socket layer is responsible for issuing SIGPIPE. */
570 if (fp->f_type != DTYPE_SOCKET && error == EPIPE) {
571 PROC_LOCK(td->td_proc);
572 tdsignal(td, SIGPIPE);
573 PROC_UNLOCK(td->td_proc);
574 }
575 }
576 cnt -= auio->uio_resid;
577 #ifdef KTRACE
578 if (ktruio != NULL) {
579 ktruio->uio_resid = cnt;
580 ktrgenio(fd, UIO_WRITE, ktruio, error);
581 }
582 #endif
583 td->td_retval[0] = cnt;
584 return (error);
585 }
586
587 /*
588 * Truncate a file given a file descriptor.
589 *
590 * Can't use fget_write() here, since must return EINVAL and not EBADF if the
591 * descriptor isn't writable.
592 */
593 int
594 kern_ftruncate(struct thread *td, int fd, off_t length)
595 {
596 struct file *fp;
597 int error;
598
599 AUDIT_ARG_FD(fd);
600 if (length < 0)
601 return (EINVAL);
602 error = fget(td, fd, &cap_ftruncate_rights, &fp);
603 if (error)
604 return (error);
605 AUDIT_ARG_FILE(td->td_proc, fp);
606 if (!(fp->f_flag & FWRITE)) {
607 fdrop(fp, td);
608 return (EINVAL);
609 }
610 error = fo_truncate(fp, length, td->td_ucred, td);
611 fdrop(fp, td);
612 return (error);
613 }
614
615 #ifndef _SYS_SYSPROTO_H_
616 struct ftruncate_args {
617 int fd;
618 int pad;
619 off_t length;
620 };
621 #endif
622 int
623 sys_ftruncate(struct thread *td, struct ftruncate_args *uap)
624 {
625
626 return (kern_ftruncate(td, uap->fd, uap->length));
627 }
628
629 #if defined(COMPAT_43)
630 #ifndef _SYS_SYSPROTO_H_
631 struct oftruncate_args {
632 int fd;
633 long length;
634 };
635 #endif
636 int
637 oftruncate(struct thread *td, struct oftruncate_args *uap)
638 {
639
640 return (kern_ftruncate(td, uap->fd, uap->length));
641 }
642 #endif /* COMPAT_43 */
643
644 #ifndef _SYS_SYSPROTO_H_
645 struct ioctl_args {
646 int fd;
647 u_long com;
648 caddr_t data;
649 };
650 #endif
651 /* ARGSUSED */
652 int
653 sys_ioctl(struct thread *td, struct ioctl_args *uap)
654 {
655 u_char smalldata[SYS_IOCTL_SMALL_SIZE] __aligned(SYS_IOCTL_SMALL_ALIGN);
656 uint32_t com;
657 int arg, error;
658 u_int size;
659 caddr_t data;
660
661 #ifdef INVARIANTS
662 if (uap->com > 0xffffffff) {
663 printf(
664 "WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
665 td->td_proc->p_pid, td->td_name, uap->com);
666 }
667 #endif
668 com = (uint32_t)uap->com;
669
670 /*
671 * Interpret high order word to find amount of data to be
672 * copied to/from the user's address space.
673 */
674 size = IOCPARM_LEN(com);
675 if ((size > IOCPARM_MAX) ||
676 ((com & (IOC_VOID | IOC_IN | IOC_OUT)) == 0) ||
677 #if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
678 ((com & IOC_OUT) && size == 0) ||
679 #else
680 ((com & (IOC_IN | IOC_OUT)) && size == 0) ||
681 #endif
682 ((com & IOC_VOID) && size > 0 && size != sizeof(int)))
683 return (ENOTTY);
684
685 if (size > 0) {
686 if (com & IOC_VOID) {
687 /* Integer argument. */
688 arg = (intptr_t)uap->data;
689 data = (void *)&arg;
690 size = 0;
691 } else {
692 if (size > SYS_IOCTL_SMALL_SIZE)
693 data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
694 else
695 data = smalldata;
696 }
697 } else
698 data = (void *)&uap->data;
699 if (com & IOC_IN) {
700 error = copyin(uap->data, data, (u_int)size);
701 if (error != 0)
702 goto out;
703 } else if (com & IOC_OUT) {
704 /*
705 * Zero the buffer so the user always
706 * gets back something deterministic.
707 */
708 bzero(data, size);
709 }
710
711 error = kern_ioctl(td, uap->fd, com, data);
712
713 if (error == 0 && (com & IOC_OUT))
714 error = copyout(data, uap->data, (u_int)size);
715
716 out:
717 if (size > SYS_IOCTL_SMALL_SIZE)
718 free(data, M_IOCTLOPS);
719 return (error);
720 }
721
722 int
723 kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
724 {
725 struct file *fp;
726 struct filedesc *fdp;
727 int error, tmp, locked;
728
729 AUDIT_ARG_FD(fd);
730 AUDIT_ARG_CMD(com);
731
732 fdp = td->td_proc->p_fd;
733
734 switch (com) {
735 case FIONCLEX:
736 case FIOCLEX:
737 FILEDESC_XLOCK(fdp);
738 locked = LA_XLOCKED;
739 break;
740 default:
741 #ifdef CAPABILITIES
742 FILEDESC_SLOCK(fdp);
743 locked = LA_SLOCKED;
744 #else
745 locked = LA_UNLOCKED;
746 #endif
747 break;
748 }
749
750 #ifdef CAPABILITIES
751 if ((fp = fget_locked(fdp, fd)) == NULL) {
752 error = EBADF;
753 goto out;
754 }
755 if ((error = cap_ioctl_check(fdp, fd, com)) != 0) {
756 fp = NULL; /* fhold() was not called yet */
757 goto out;
758 }
759 if (!fhold(fp)) {
760 error = EBADF;
761 fp = NULL;
762 goto out;
763 }
764 if (locked == LA_SLOCKED) {
765 FILEDESC_SUNLOCK(fdp);
766 locked = LA_UNLOCKED;
767 }
768 #else
769 error = fget(td, fd, &cap_ioctl_rights, &fp);
770 if (error != 0) {
771 fp = NULL;
772 goto out;
773 }
774 #endif
775 if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
776 error = EBADF;
777 goto out;
778 }
779
780 switch (com) {
781 case FIONCLEX:
782 fdp->fd_ofiles[fd].fde_flags &= ~UF_EXCLOSE;
783 goto out;
784 case FIOCLEX:
785 fdp->fd_ofiles[fd].fde_flags |= UF_EXCLOSE;
786 goto out;
787 case FIONBIO:
788 if ((tmp = *(int *)data))
789 atomic_set_int(&fp->f_flag, FNONBLOCK);
790 else
791 atomic_clear_int(&fp->f_flag, FNONBLOCK);
792 data = (void *)&tmp;
793 break;
794 case FIOASYNC:
795 if ((tmp = *(int *)data))
796 atomic_set_int(&fp->f_flag, FASYNC);
797 else
798 atomic_clear_int(&fp->f_flag, FASYNC);
799 data = (void *)&tmp;
800 break;
801 }
802
803 error = fo_ioctl(fp, com, data, td->td_ucred, td);
804 out:
805 switch (locked) {
806 case LA_XLOCKED:
807 FILEDESC_XUNLOCK(fdp);
808 break;
809 #ifdef CAPABILITIES
810 case LA_SLOCKED:
811 FILEDESC_SUNLOCK(fdp);
812 break;
813 #endif
814 default:
815 FILEDESC_UNLOCK_ASSERT(fdp);
816 break;
817 }
818 if (fp != NULL)
819 fdrop(fp, td);
820 return (error);
821 }
822
823 int
824 sys_posix_fallocate(struct thread *td, struct posix_fallocate_args *uap)
825 {
826 int error;
827
828 error = kern_posix_fallocate(td, uap->fd, uap->offset, uap->len);
829 return (kern_posix_error(td, error));
830 }
831
832 int
833 kern_posix_fallocate(struct thread *td, int fd, off_t offset, off_t len)
834 {
835 struct file *fp;
836 int error;
837
838 AUDIT_ARG_FD(fd);
839 if (offset < 0 || len <= 0)
840 return (EINVAL);
841 /* Check for wrap. */
842 if (offset > OFF_MAX - len)
843 return (EFBIG);
844 AUDIT_ARG_FD(fd);
845 error = fget(td, fd, &cap_pwrite_rights, &fp);
846 if (error != 0)
847 return (error);
848 AUDIT_ARG_FILE(td->td_proc, fp);
849 if ((fp->f_ops->fo_flags & DFLAG_SEEKABLE) == 0) {
850 error = ESPIPE;
851 goto out;
852 }
853 if ((fp->f_flag & FWRITE) == 0) {
854 error = EBADF;
855 goto out;
856 }
857
858 error = fo_fallocate(fp, offset, len, td);
859 out:
860 fdrop(fp, td);
861 return (error);
862 }
863
864 int
865 kern_specialfd(struct thread *td, int type, void *arg)
866 {
867 struct file *fp;
868 struct specialfd_eventfd *ae;
869 int error, fd, fflags;
870
871 fflags = 0;
872 error = falloc_noinstall(td, &fp);
873 if (error != 0)
874 return (error);
875
876 switch (type) {
877 case SPECIALFD_EVENTFD:
878 ae = arg;
879 if ((ae->flags & EFD_CLOEXEC) != 0)
880 fflags |= O_CLOEXEC;
881 error = eventfd_create_file(td, fp, ae->initval, ae->flags);
882 break;
883 default:
884 error = EINVAL;
885 break;
886 }
887
888 if (error == 0)
889 error = finstall(td, fp, &fd, fflags, NULL);
890 fdrop(fp, td);
891 if (error == 0)
892 td->td_retval[0] = fd;
893 return (error);
894 }
895
896 int
897 sys___specialfd(struct thread *td, struct __specialfd_args *args)
898 {
899 struct specialfd_eventfd ae;
900 int error;
901
902 switch (args->type) {
903 case SPECIALFD_EVENTFD:
904 if (args->len != sizeof(struct specialfd_eventfd)) {
905 error = EINVAL;
906 break;
907 }
908 error = copyin(args->req, &ae, sizeof(ae));
909 if (error != 0)
910 break;
911 if ((ae.flags & ~(EFD_CLOEXEC | EFD_NONBLOCK |
912 EFD_SEMAPHORE)) != 0) {
913 error = EINVAL;
914 break;
915 }
916 error = kern_specialfd(td, args->type, &ae);
917 break;
918 default:
919 error = EINVAL;
920 break;
921 }
922 return (error);
923 }
924
925 int
926 poll_no_poll(int events)
927 {
928 /*
929 * Return true for read/write. If the user asked for something
930 * special, return POLLNVAL, so that clients have a way of
931 * determining reliably whether or not the extended
932 * functionality is present without hard-coding knowledge
933 * of specific filesystem implementations.
934 */
935 if (events & ~POLLSTANDARD)
936 return (POLLNVAL);
937
938 return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
939 }
940
941 int
942 sys_pselect(struct thread *td, struct pselect_args *uap)
943 {
944 struct timespec ts;
945 struct timeval tv, *tvp;
946 sigset_t set, *uset;
947 int error;
948
949 if (uap->ts != NULL) {
950 error = copyin(uap->ts, &ts, sizeof(ts));
951 if (error != 0)
952 return (error);
953 TIMESPEC_TO_TIMEVAL(&tv, &ts);
954 tvp = &tv;
955 } else
956 tvp = NULL;
957 if (uap->sm != NULL) {
958 error = copyin(uap->sm, &set, sizeof(set));
959 if (error != 0)
960 return (error);
961 uset = &set;
962 } else
963 uset = NULL;
964 return (kern_pselect(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
965 uset, NFDBITS));
966 }
967
968 int
969 kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou, fd_set *ex,
970 struct timeval *tvp, sigset_t *uset, int abi_nfdbits)
971 {
972 int error;
973
974 if (uset != NULL) {
975 error = kern_sigprocmask(td, SIG_SETMASK, uset,
976 &td->td_oldsigmask, 0);
977 if (error != 0)
978 return (error);
979 td->td_pflags |= TDP_OLDMASK;
980 /*
981 * Make sure that ast() is called on return to
982 * usermode and TDP_OLDMASK is cleared, restoring old
983 * sigmask.
984 */
985 thread_lock(td);
986 td->td_flags |= TDF_ASTPENDING;
987 thread_unlock(td);
988 }
989 error = kern_select(td, nd, in, ou, ex, tvp, abi_nfdbits);
990 return (error);
991 }
992
993 #ifndef _SYS_SYSPROTO_H_
994 struct select_args {
995 int nd;
996 fd_set *in, *ou, *ex;
997 struct timeval *tv;
998 };
999 #endif
1000 int
1001 sys_select(struct thread *td, struct select_args *uap)
1002 {
1003 struct timeval tv, *tvp;
1004 int error;
1005
1006 if (uap->tv != NULL) {
1007 error = copyin(uap->tv, &tv, sizeof(tv));
1008 if (error)
1009 return (error);
1010 tvp = &tv;
1011 } else
1012 tvp = NULL;
1013
1014 return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp,
1015 NFDBITS));
1016 }
1017
1018 /*
1019 * In the unlikely case when user specified n greater then the last
1020 * open file descriptor, check that no bits are set after the last
1021 * valid fd. We must return EBADF if any is set.
1022 *
1023 * There are applications that rely on the behaviour.
1024 *
1025 * nd is fd_nfiles.
1026 */
1027 static int
1028 select_check_badfd(fd_set *fd_in, int nd, int ndu, int abi_nfdbits)
1029 {
1030 char *addr, *oaddr;
1031 int b, i, res;
1032 uint8_t bits;
1033
1034 if (nd >= ndu || fd_in == NULL)
1035 return (0);
1036
1037 oaddr = NULL;
1038 bits = 0; /* silence gcc */
1039 for (i = nd; i < ndu; i++) {
1040 b = i / NBBY;
1041 #if BYTE_ORDER == LITTLE_ENDIAN
1042 addr = (char *)fd_in + b;
1043 #else
1044 addr = (char *)fd_in;
1045 if (abi_nfdbits == NFDBITS) {
1046 addr += rounddown(b, sizeof(fd_mask)) +
1047 sizeof(fd_mask) - 1 - b % sizeof(fd_mask);
1048 } else {
1049 addr += rounddown(b, sizeof(uint32_t)) +
1050 sizeof(uint32_t) - 1 - b % sizeof(uint32_t);
1051 }
1052 #endif
1053 if (addr != oaddr) {
1054 res = fubyte(addr);
1055 if (res == -1)
1056 return (EFAULT);
1057 oaddr = addr;
1058 bits = res;
1059 }
1060 if ((bits & (1 << (i % NBBY))) != 0)
1061 return (EBADF);
1062 }
1063 return (0);
1064 }
1065
1066 int
1067 kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
1068 fd_set *fd_ex, struct timeval *tvp, int abi_nfdbits)
1069 {
1070 struct filedesc *fdp;
1071 /*
1072 * The magic 2048 here is chosen to be just enough for FD_SETSIZE
1073 * infds with the new FD_SETSIZE of 1024, and more than enough for
1074 * FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
1075 * of 256.
1076 */
1077 fd_mask s_selbits[howmany(2048, NFDBITS)];
1078 fd_mask *ibits[3], *obits[3], *selbits, *sbp;
1079 struct timeval rtv;
1080 sbintime_t asbt, precision, rsbt;
1081 u_int nbufbytes, ncpbytes, ncpubytes, nfdbits;
1082 int error, lf, ndu;
1083
1084 if (nd < 0)
1085 return (EINVAL);
1086 fdp = td->td_proc->p_fd;
1087 ndu = nd;
1088 lf = fdp->fd_nfiles;
1089 if (nd > lf)
1090 nd = lf;
1091
1092 error = select_check_badfd(fd_in, nd, ndu, abi_nfdbits);
1093 if (error != 0)
1094 return (error);
1095 error = select_check_badfd(fd_ou, nd, ndu, abi_nfdbits);
1096 if (error != 0)
1097 return (error);
1098 error = select_check_badfd(fd_ex, nd, ndu, abi_nfdbits);
1099 if (error != 0)
1100 return (error);
1101
1102 /*
1103 * Allocate just enough bits for the non-null fd_sets. Use the
1104 * preallocated auto buffer if possible.
1105 */
1106 nfdbits = roundup(nd, NFDBITS);
1107 ncpbytes = nfdbits / NBBY;
1108 ncpubytes = roundup(nd, abi_nfdbits) / NBBY;
1109 nbufbytes = 0;
1110 if (fd_in != NULL)
1111 nbufbytes += 2 * ncpbytes;
1112 if (fd_ou != NULL)
1113 nbufbytes += 2 * ncpbytes;
1114 if (fd_ex != NULL)
1115 nbufbytes += 2 * ncpbytes;
1116 if (nbufbytes <= sizeof s_selbits)
1117 selbits = &s_selbits[0];
1118 else
1119 selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
1120
1121 /*
1122 * Assign pointers into the bit buffers and fetch the input bits.
1123 * Put the output buffers together so that they can be bzeroed
1124 * together.
1125 */
1126 sbp = selbits;
1127 #define getbits(name, x) \
1128 do { \
1129 if (name == NULL) { \
1130 ibits[x] = NULL; \
1131 obits[x] = NULL; \
1132 } else { \
1133 ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp; \
1134 obits[x] = sbp; \
1135 sbp += ncpbytes / sizeof *sbp; \
1136 error = copyin(name, ibits[x], ncpubytes); \
1137 if (error != 0) \
1138 goto done; \
1139 if (ncpbytes != ncpubytes) \
1140 bzero((char *)ibits[x] + ncpubytes, \
1141 ncpbytes - ncpubytes); \
1142 } \
1143 } while (0)
1144 getbits(fd_in, 0);
1145 getbits(fd_ou, 1);
1146 getbits(fd_ex, 2);
1147 #undef getbits
1148
1149 #if BYTE_ORDER == BIG_ENDIAN && defined(__LP64__)
1150 /*
1151 * XXX: swizzle_fdset assumes that if abi_nfdbits != NFDBITS,
1152 * we are running under 32-bit emulation. This should be more
1153 * generic.
1154 */
1155 #define swizzle_fdset(bits) \
1156 if (abi_nfdbits != NFDBITS && bits != NULL) { \
1157 int i; \
1158 for (i = 0; i < ncpbytes / sizeof *sbp; i++) \
1159 bits[i] = (bits[i] >> 32) | (bits[i] << 32); \
1160 }
1161 #else
1162 #define swizzle_fdset(bits)
1163 #endif
1164
1165 /* Make sure the bit order makes it through an ABI transition */
1166 swizzle_fdset(ibits[0]);
1167 swizzle_fdset(ibits[1]);
1168 swizzle_fdset(ibits[2]);
1169
1170 if (nbufbytes != 0)
1171 bzero(selbits, nbufbytes / 2);
1172
1173 precision = 0;
1174 if (tvp != NULL) {
1175 rtv = *tvp;
1176 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
1177 rtv.tv_usec >= 1000000) {
1178 error = EINVAL;
1179 goto done;
1180 }
1181 if (!timevalisset(&rtv))
1182 asbt = 0;
1183 else if (rtv.tv_sec <= INT32_MAX) {
1184 rsbt = tvtosbt(rtv);
1185 precision = rsbt;
1186 precision >>= tc_precexp;
1187 if (TIMESEL(&asbt, rsbt))
1188 asbt += tc_tick_sbt;
1189 if (asbt <= SBT_MAX - rsbt)
1190 asbt += rsbt;
1191 else
1192 asbt = -1;
1193 } else
1194 asbt = -1;
1195 } else
1196 asbt = -1;
1197 seltdinit(td);
1198 /* Iterate until the timeout expires or descriptors become ready. */
1199 for (;;) {
1200 error = selscan(td, ibits, obits, nd);
1201 if (error || td->td_retval[0] != 0)
1202 break;
1203 error = seltdwait(td, asbt, precision);
1204 if (error)
1205 break;
1206 error = selrescan(td, ibits, obits);
1207 if (error || td->td_retval[0] != 0)
1208 break;
1209 }
1210 seltdclear(td);
1211
1212 done:
1213 /* select is not restarted after signals... */
1214 if (error == ERESTART)
1215 error = EINTR;
1216 if (error == EWOULDBLOCK)
1217 error = 0;
1218
1219 /* swizzle bit order back, if necessary */
1220 swizzle_fdset(obits[0]);
1221 swizzle_fdset(obits[1]);
1222 swizzle_fdset(obits[2]);
1223 #undef swizzle_fdset
1224
1225 #define putbits(name, x) \
1226 if (name && (error2 = copyout(obits[x], name, ncpubytes))) \
1227 error = error2;
1228 if (error == 0) {
1229 int error2;
1230
1231 putbits(fd_in, 0);
1232 putbits(fd_ou, 1);
1233 putbits(fd_ex, 2);
1234 #undef putbits
1235 }
1236 if (selbits != &s_selbits[0])
1237 free(selbits, M_SELECT);
1238
1239 return (error);
1240 }
1241 /*
1242 * Convert a select bit set to poll flags.
1243 *
1244 * The backend always returns POLLHUP/POLLERR if appropriate and we
1245 * return this as a set bit in any set.
1246 */
1247 static const int select_flags[3] = {
1248 POLLRDNORM | POLLHUP | POLLERR,
1249 POLLWRNORM | POLLHUP | POLLERR,
1250 POLLRDBAND | POLLERR
1251 };
1252
1253 /*
1254 * Compute the fo_poll flags required for a fd given by the index and
1255 * bit position in the fd_mask array.
1256 */
1257 static __inline int
1258 selflags(fd_mask **ibits, int idx, fd_mask bit)
1259 {
1260 int flags;
1261 int msk;
1262
1263 flags = 0;
1264 for (msk = 0; msk < 3; msk++) {
1265 if (ibits[msk] == NULL)
1266 continue;
1267 if ((ibits[msk][idx] & bit) == 0)
1268 continue;
1269 flags |= select_flags[msk];
1270 }
1271 return (flags);
1272 }
1273
1274 /*
1275 * Set the appropriate output bits given a mask of fired events and the
1276 * input bits originally requested.
1277 */
1278 static __inline int
1279 selsetbits(fd_mask **ibits, fd_mask **obits, int idx, fd_mask bit, int events)
1280 {
1281 int msk;
1282 int n;
1283
1284 n = 0;
1285 for (msk = 0; msk < 3; msk++) {
1286 if ((events & select_flags[msk]) == 0)
1287 continue;
1288 if (ibits[msk] == NULL)
1289 continue;
1290 if ((ibits[msk][idx] & bit) == 0)
1291 continue;
1292 /*
1293 * XXX Check for a duplicate set. This can occur because a
1294 * socket calls selrecord() twice for each poll() call
1295 * resulting in two selfds per real fd. selrescan() will
1296 * call selsetbits twice as a result.
1297 */
1298 if ((obits[msk][idx] & bit) != 0)
1299 continue;
1300 obits[msk][idx] |= bit;
1301 n++;
1302 }
1303
1304 return (n);
1305 }
1306
1307 /*
1308 * Traverse the list of fds attached to this thread's seltd and check for
1309 * completion.
1310 */
1311 static int
1312 selrescan(struct thread *td, fd_mask **ibits, fd_mask **obits)
1313 {
1314 struct filedesc *fdp;
1315 struct selinfo *si;
1316 struct seltd *stp;
1317 struct selfd *sfp;
1318 struct selfd *sfn;
1319 struct file *fp;
1320 fd_mask bit;
1321 int fd, ev, n, idx;
1322 int error;
1323 bool only_user;
1324
1325 fdp = td->td_proc->p_fd;
1326 stp = td->td_sel;
1327 n = 0;
1328 only_user = FILEDESC_IS_ONLY_USER(fdp);
1329 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
1330 fd = (int)(uintptr_t)sfp->sf_cookie;
1331 si = sfp->sf_si;
1332 selfdfree(stp, sfp);
1333 /* If the selinfo wasn't cleared the event didn't fire. */
1334 if (si != NULL)
1335 continue;
1336 if (only_user)
1337 error = fget_only_user(fdp, fd, &cap_event_rights, &fp);
1338 else
1339 error = fget_unlocked(fdp, fd, &cap_event_rights, &fp);
1340 if (__predict_false(error != 0))
1341 return (error);
1342 idx = fd / NFDBITS;
1343 bit = (fd_mask)1 << (fd % NFDBITS);
1344 ev = fo_poll(fp, selflags(ibits, idx, bit), td->td_ucred, td);
1345 if (only_user)
1346 fput_only_user(fdp, fp);
1347 else
1348 fdrop(fp, td);
1349 if (ev != 0)
1350 n += selsetbits(ibits, obits, idx, bit, ev);
1351 }
1352 stp->st_flags = 0;
1353 td->td_retval[0] = n;
1354 return (0);
1355 }
1356
1357 /*
1358 * Perform the initial filedescriptor scan and register ourselves with
1359 * each selinfo.
1360 */
1361 static int
1362 selscan(struct thread *td, fd_mask **ibits, fd_mask **obits, int nfd)
1363 {
1364 struct filedesc *fdp;
1365 struct file *fp;
1366 fd_mask bit;
1367 int ev, flags, end, fd;
1368 int n, idx;
1369 int error;
1370 bool only_user;
1371
1372 fdp = td->td_proc->p_fd;
1373 n = 0;
1374 only_user = FILEDESC_IS_ONLY_USER(fdp);
1375 for (idx = 0, fd = 0; fd < nfd; idx++) {
1376 end = imin(fd + NFDBITS, nfd);
1377 for (bit = 1; fd < end; bit <<= 1, fd++) {
1378 /* Compute the list of events we're interested in. */
1379 flags = selflags(ibits, idx, bit);
1380 if (flags == 0)
1381 continue;
1382 if (only_user)
1383 error = fget_only_user(fdp, fd, &cap_event_rights, &fp);
1384 else
1385 error = fget_unlocked(fdp, fd, &cap_event_rights, &fp);
1386 if (__predict_false(error != 0))
1387 return (error);
1388 selfdalloc(td, (void *)(uintptr_t)fd);
1389 ev = fo_poll(fp, flags, td->td_ucred, td);
1390 if (only_user)
1391 fput_only_user(fdp, fp);
1392 else
1393 fdrop(fp, td);
1394 if (ev != 0)
1395 n += selsetbits(ibits, obits, idx, bit, ev);
1396 }
1397 }
1398
1399 td->td_retval[0] = n;
1400 return (0);
1401 }
1402
1403 int
1404 sys_poll(struct thread *td, struct poll_args *uap)
1405 {
1406 struct timespec ts, *tsp;
1407
1408 if (uap->timeout != INFTIM) {
1409 if (uap->timeout < 0)
1410 return (EINVAL);
1411 ts.tv_sec = uap->timeout / 1000;
1412 ts.tv_nsec = (uap->timeout % 1000) * 1000000;
1413 tsp = &ts;
1414 } else
1415 tsp = NULL;
1416
1417 return (kern_poll(td, uap->fds, uap->nfds, tsp, NULL));
1418 }
1419
1420 /*
1421 * kfds points to an array in the kernel.
1422 */
1423 int
1424 kern_poll_kfds(struct thread *td, struct pollfd *kfds, u_int nfds,
1425 struct timespec *tsp, sigset_t *uset)
1426 {
1427 sbintime_t sbt, precision, tmp;
1428 time_t over;
1429 struct timespec ts;
1430 int error;
1431
1432 precision = 0;
1433 if (tsp != NULL) {
1434 if (!timespecvalid_interval(tsp))
1435 return (EINVAL);
1436 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
1437 sbt = 0;
1438 else {
1439 ts = *tsp;
1440 if (ts.tv_sec > INT32_MAX / 2) {
1441 over = ts.tv_sec - INT32_MAX / 2;
1442 ts.tv_sec -= over;
1443 } else
1444 over = 0;
1445 tmp = tstosbt(ts);
1446 precision = tmp;
1447 precision >>= tc_precexp;
1448 if (TIMESEL(&sbt, tmp))
1449 sbt += tc_tick_sbt;
1450 sbt += tmp;
1451 }
1452 } else
1453 sbt = -1;
1454
1455 if (uset != NULL) {
1456 error = kern_sigprocmask(td, SIG_SETMASK, uset,
1457 &td->td_oldsigmask, 0);
1458 if (error)
1459 return (error);
1460 td->td_pflags |= TDP_OLDMASK;
1461 /*
1462 * Make sure that ast() is called on return to
1463 * usermode and TDP_OLDMASK is cleared, restoring old
1464 * sigmask.
1465 */
1466 thread_lock(td);
1467 td->td_flags |= TDF_ASTPENDING;
1468 thread_unlock(td);
1469 }
1470
1471 seltdinit(td);
1472 /* Iterate until the timeout expires or descriptors become ready. */
1473 for (;;) {
1474 error = pollscan(td, kfds, nfds);
1475 if (error || td->td_retval[0] != 0)
1476 break;
1477 error = seltdwait(td, sbt, precision);
1478 if (error)
1479 break;
1480 error = pollrescan(td);
1481 if (error || td->td_retval[0] != 0)
1482 break;
1483 }
1484 seltdclear(td);
1485
1486 /* poll is not restarted after signals... */
1487 if (error == ERESTART)
1488 error = EINTR;
1489 if (error == EWOULDBLOCK)
1490 error = 0;
1491 return (error);
1492 }
1493
1494 int
1495 sys_ppoll(struct thread *td, struct ppoll_args *uap)
1496 {
1497 struct timespec ts, *tsp;
1498 sigset_t set, *ssp;
1499 int error;
1500
1501 if (uap->ts != NULL) {
1502 error = copyin(uap->ts, &ts, sizeof(ts));
1503 if (error)
1504 return (error);
1505 tsp = &ts;
1506 } else
1507 tsp = NULL;
1508 if (uap->set != NULL) {
1509 error = copyin(uap->set, &set, sizeof(set));
1510 if (error)
1511 return (error);
1512 ssp = &set;
1513 } else
1514 ssp = NULL;
1515 return (kern_poll(td, uap->fds, uap->nfds, tsp, ssp));
1516 }
1517
1518 /*
1519 * ufds points to an array in user space.
1520 */
1521 int
1522 kern_poll(struct thread *td, struct pollfd *ufds, u_int nfds,
1523 struct timespec *tsp, sigset_t *set)
1524 {
1525 struct pollfd *kfds;
1526 struct pollfd stackfds[32];
1527 int error;
1528
1529 if (kern_poll_maxfds(nfds))
1530 return (EINVAL);
1531 if (nfds > nitems(stackfds))
1532 kfds = mallocarray(nfds, sizeof(*kfds), M_TEMP, M_WAITOK);
1533 else
1534 kfds = stackfds;
1535 error = copyin(ufds, kfds, nfds * sizeof(*kfds));
1536 if (error != 0)
1537 goto out;
1538
1539 error = kern_poll_kfds(td, kfds, nfds, tsp, set);
1540 if (error == 0)
1541 error = pollout(td, kfds, ufds, nfds);
1542
1543 out:
1544 if (nfds > nitems(stackfds))
1545 free(kfds, M_TEMP);
1546 return (error);
1547 }
1548
1549 bool
1550 kern_poll_maxfds(u_int nfds)
1551 {
1552
1553 /*
1554 * This is kinda bogus. We have fd limits, but that is not
1555 * really related to the size of the pollfd array. Make sure
1556 * we let the process use at least FD_SETSIZE entries and at
1557 * least enough for the system-wide limits. We want to be reasonably
1558 * safe, but not overly restrictive.
1559 */
1560 return (nfds > maxfilesperproc && nfds > FD_SETSIZE);
1561 }
1562
1563 static int
1564 pollrescan(struct thread *td)
1565 {
1566 struct seltd *stp;
1567 struct selfd *sfp;
1568 struct selfd *sfn;
1569 struct selinfo *si;
1570 struct filedesc *fdp;
1571 struct file *fp;
1572 struct pollfd *fd;
1573 int n, error;
1574 bool only_user;
1575
1576 n = 0;
1577 fdp = td->td_proc->p_fd;
1578 stp = td->td_sel;
1579 only_user = FILEDESC_IS_ONLY_USER(fdp);
1580 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn) {
1581 fd = (struct pollfd *)sfp->sf_cookie;
1582 si = sfp->sf_si;
1583 selfdfree(stp, sfp);
1584 /* If the selinfo wasn't cleared the event didn't fire. */
1585 if (si != NULL)
1586 continue;
1587 if (only_user)
1588 error = fget_only_user(fdp, fd->fd, &cap_event_rights, &fp);
1589 else
1590 error = fget_unlocked(fdp, fd->fd, &cap_event_rights, &fp);
1591 if (__predict_false(error != 0)) {
1592 fd->revents = POLLNVAL;
1593 n++;
1594 continue;
1595 }
1596 /*
1597 * Note: backend also returns POLLHUP and
1598 * POLLERR if appropriate.
1599 */
1600 fd->revents = fo_poll(fp, fd->events, td->td_ucred, td);
1601 if (only_user)
1602 fput_only_user(fdp, fp);
1603 else
1604 fdrop(fp, td);
1605 if (fd->revents != 0)
1606 n++;
1607 }
1608 stp->st_flags = 0;
1609 td->td_retval[0] = n;
1610 return (0);
1611 }
1612
1613 static int
1614 pollout(struct thread *td, struct pollfd *fds, struct pollfd *ufds, u_int nfd)
1615 {
1616 int error = 0;
1617 u_int i = 0;
1618 u_int n = 0;
1619
1620 for (i = 0; i < nfd; i++) {
1621 error = copyout(&fds->revents, &ufds->revents,
1622 sizeof(ufds->revents));
1623 if (error)
1624 return (error);
1625 if (fds->revents != 0)
1626 n++;
1627 fds++;
1628 ufds++;
1629 }
1630 td->td_retval[0] = n;
1631 return (0);
1632 }
1633
1634 static int
1635 pollscan(struct thread *td, struct pollfd *fds, u_int nfd)
1636 {
1637 struct filedesc *fdp;
1638 struct file *fp;
1639 int i, n, error;
1640 bool only_user;
1641
1642 n = 0;
1643 fdp = td->td_proc->p_fd;
1644 only_user = FILEDESC_IS_ONLY_USER(fdp);
1645 for (i = 0; i < nfd; i++, fds++) {
1646 if (fds->fd < 0) {
1647 fds->revents = 0;
1648 continue;
1649 }
1650 if (only_user)
1651 error = fget_only_user(fdp, fds->fd, &cap_event_rights, &fp);
1652 else
1653 error = fget_unlocked(fdp, fds->fd, &cap_event_rights, &fp);
1654 if (__predict_false(error != 0)) {
1655 fds->revents = POLLNVAL;
1656 n++;
1657 continue;
1658 }
1659 /*
1660 * Note: backend also returns POLLHUP and
1661 * POLLERR if appropriate.
1662 */
1663 selfdalloc(td, fds);
1664 fds->revents = fo_poll(fp, fds->events,
1665 td->td_ucred, td);
1666 if (only_user)
1667 fput_only_user(fdp, fp);
1668 else
1669 fdrop(fp, td);
1670 /*
1671 * POSIX requires POLLOUT to be never
1672 * set simultaneously with POLLHUP.
1673 */
1674 if ((fds->revents & POLLHUP) != 0)
1675 fds->revents &= ~POLLOUT;
1676
1677 if (fds->revents != 0)
1678 n++;
1679 }
1680 td->td_retval[0] = n;
1681 return (0);
1682 }
1683
1684 /*
1685 * XXX This was created specifically to support netncp and netsmb. This
1686 * allows the caller to specify a socket to wait for events on. It returns
1687 * 0 if any events matched and an error otherwise. There is no way to
1688 * determine which events fired.
1689 */
1690 int
1691 selsocket(struct socket *so, int events, struct timeval *tvp, struct thread *td)
1692 {
1693 struct timeval rtv;
1694 sbintime_t asbt, precision, rsbt;
1695 int error;
1696
1697 precision = 0; /* stupid gcc! */
1698 if (tvp != NULL) {
1699 rtv = *tvp;
1700 if (rtv.tv_sec < 0 || rtv.tv_usec < 0 ||
1701 rtv.tv_usec >= 1000000)
1702 return (EINVAL);
1703 if (!timevalisset(&rtv))
1704 asbt = 0;
1705 else if (rtv.tv_sec <= INT32_MAX) {
1706 rsbt = tvtosbt(rtv);
1707 precision = rsbt;
1708 precision >>= tc_precexp;
1709 if (TIMESEL(&asbt, rsbt))
1710 asbt += tc_tick_sbt;
1711 if (asbt <= SBT_MAX - rsbt)
1712 asbt += rsbt;
1713 else
1714 asbt = -1;
1715 } else
1716 asbt = -1;
1717 } else
1718 asbt = -1;
1719 seltdinit(td);
1720 /*
1721 * Iterate until the timeout expires or the socket becomes ready.
1722 */
1723 for (;;) {
1724 selfdalloc(td, NULL);
1725 if (sopoll(so, events, NULL, td) != 0) {
1726 error = 0;
1727 break;
1728 }
1729 error = seltdwait(td, asbt, precision);
1730 if (error)
1731 break;
1732 }
1733 seltdclear(td);
1734 /* XXX Duplicates ncp/smb behavior. */
1735 if (error == ERESTART)
1736 error = 0;
1737 return (error);
1738 }
1739
1740 /*
1741 * Preallocate two selfds associated with 'cookie'. Some fo_poll routines
1742 * have two select sets, one for read and another for write.
1743 */
1744 static void
1745 selfdalloc(struct thread *td, void *cookie)
1746 {
1747 struct seltd *stp;
1748
1749 stp = td->td_sel;
1750 if (stp->st_free1 == NULL)
1751 stp->st_free1 = malloc(sizeof(*stp->st_free1), M_SELFD, M_WAITOK|M_ZERO);
1752 stp->st_free1->sf_td = stp;
1753 stp->st_free1->sf_cookie = cookie;
1754 if (stp->st_free2 == NULL)
1755 stp->st_free2 = malloc(sizeof(*stp->st_free2), M_SELFD, M_WAITOK|M_ZERO);
1756 stp->st_free2->sf_td = stp;
1757 stp->st_free2->sf_cookie = cookie;
1758 }
1759
1760 static void
1761 selfdfree(struct seltd *stp, struct selfd *sfp)
1762 {
1763 STAILQ_REMOVE(&stp->st_selq, sfp, selfd, sf_link);
1764 /*
1765 * Paired with doselwakeup.
1766 */
1767 if (atomic_load_acq_ptr((uintptr_t *)&sfp->sf_si) != (uintptr_t)NULL) {
1768 mtx_lock(sfp->sf_mtx);
1769 if (sfp->sf_si != NULL) {
1770 TAILQ_REMOVE(&sfp->sf_si->si_tdlist, sfp, sf_threads);
1771 }
1772 mtx_unlock(sfp->sf_mtx);
1773 }
1774 free(sfp, M_SELFD);
1775 }
1776
1777 /* Drain the waiters tied to all the selfd belonging the specified selinfo. */
1778 void
1779 seldrain(struct selinfo *sip)
1780 {
1781
1782 /*
1783 * This feature is already provided by doselwakeup(), thus it is
1784 * enough to go for it.
1785 * Eventually, the context, should take care to avoid races
1786 * between thread calling select()/poll() and file descriptor
1787 * detaching, but, again, the races are just the same as
1788 * selwakeup().
1789 */
1790 doselwakeup(sip, -1);
1791 }
1792
1793 /*
1794 * Record a select request.
1795 */
1796 void
1797 selrecord(struct thread *selector, struct selinfo *sip)
1798 {
1799 struct selfd *sfp;
1800 struct seltd *stp;
1801 struct mtx *mtxp;
1802
1803 stp = selector->td_sel;
1804 /*
1805 * Don't record when doing a rescan.
1806 */
1807 if (stp->st_flags & SELTD_RESCAN)
1808 return;
1809 /*
1810 * Grab one of the preallocated descriptors.
1811 */
1812 sfp = NULL;
1813 if ((sfp = stp->st_free1) != NULL)
1814 stp->st_free1 = NULL;
1815 else if ((sfp = stp->st_free2) != NULL)
1816 stp->st_free2 = NULL;
1817 else
1818 panic("selrecord: No free selfd on selq");
1819 mtxp = sip->si_mtx;
1820 if (mtxp == NULL)
1821 mtxp = mtx_pool_find(mtxpool_select, sip);
1822 /*
1823 * Initialize the sfp and queue it in the thread.
1824 */
1825 sfp->sf_si = sip;
1826 sfp->sf_mtx = mtxp;
1827 STAILQ_INSERT_TAIL(&stp->st_selq, sfp, sf_link);
1828 /*
1829 * Now that we've locked the sip, check for initialization.
1830 */
1831 mtx_lock(mtxp);
1832 if (sip->si_mtx == NULL) {
1833 sip->si_mtx = mtxp;
1834 TAILQ_INIT(&sip->si_tdlist);
1835 }
1836 /*
1837 * Add this thread to the list of selfds listening on this selinfo.
1838 */
1839 TAILQ_INSERT_TAIL(&sip->si_tdlist, sfp, sf_threads);
1840 mtx_unlock(sip->si_mtx);
1841 }
1842
1843 /* Wake up a selecting thread. */
1844 void
1845 selwakeup(struct selinfo *sip)
1846 {
1847 doselwakeup(sip, -1);
1848 }
1849
1850 /* Wake up a selecting thread, and set its priority. */
1851 void
1852 selwakeuppri(struct selinfo *sip, int pri)
1853 {
1854 doselwakeup(sip, pri);
1855 }
1856
1857 /*
1858 * Do a wakeup when a selectable event occurs.
1859 */
1860 static void
1861 doselwakeup(struct selinfo *sip, int pri)
1862 {
1863 struct selfd *sfp;
1864 struct selfd *sfn;
1865 struct seltd *stp;
1866
1867 /* If it's not initialized there can't be any waiters. */
1868 if (sip->si_mtx == NULL)
1869 return;
1870 /*
1871 * Locking the selinfo locks all selfds associated with it.
1872 */
1873 mtx_lock(sip->si_mtx);
1874 TAILQ_FOREACH_SAFE(sfp, &sip->si_tdlist, sf_threads, sfn) {
1875 /*
1876 * Once we remove this sfp from the list and clear the
1877 * sf_si seltdclear will know to ignore this si.
1878 */
1879 TAILQ_REMOVE(&sip->si_tdlist, sfp, sf_threads);
1880 stp = sfp->sf_td;
1881 mtx_lock(&stp->st_mtx);
1882 stp->st_flags |= SELTD_PENDING;
1883 cv_broadcastpri(&stp->st_wait, pri);
1884 mtx_unlock(&stp->st_mtx);
1885 /*
1886 * Paired with selfdfree.
1887 *
1888 * Storing this only after the wakeup provides an invariant that
1889 * stp is not used after selfdfree returns.
1890 */
1891 atomic_store_rel_ptr((uintptr_t *)&sfp->sf_si, (uintptr_t)NULL);
1892 }
1893 mtx_unlock(sip->si_mtx);
1894 }
1895
1896 static void
1897 seltdinit(struct thread *td)
1898 {
1899 struct seltd *stp;
1900
1901 stp = td->td_sel;
1902 if (stp != NULL) {
1903 MPASS(stp->st_flags == 0);
1904 MPASS(STAILQ_EMPTY(&stp->st_selq));
1905 return;
1906 }
1907 stp = malloc(sizeof(*stp), M_SELECT, M_WAITOK|M_ZERO);
1908 mtx_init(&stp->st_mtx, "sellck", NULL, MTX_DEF);
1909 cv_init(&stp->st_wait, "select");
1910 stp->st_flags = 0;
1911 STAILQ_INIT(&stp->st_selq);
1912 td->td_sel = stp;
1913 }
1914
1915 static int
1916 seltdwait(struct thread *td, sbintime_t sbt, sbintime_t precision)
1917 {
1918 struct seltd *stp;
1919 int error;
1920
1921 stp = td->td_sel;
1922 /*
1923 * An event of interest may occur while we do not hold the seltd
1924 * locked so check the pending flag before we sleep.
1925 */
1926 mtx_lock(&stp->st_mtx);
1927 /*
1928 * Any further calls to selrecord will be a rescan.
1929 */
1930 stp->st_flags |= SELTD_RESCAN;
1931 if (stp->st_flags & SELTD_PENDING) {
1932 mtx_unlock(&stp->st_mtx);
1933 return (0);
1934 }
1935 if (sbt == 0)
1936 error = EWOULDBLOCK;
1937 else if (sbt != -1)
1938 error = cv_timedwait_sig_sbt(&stp->st_wait, &stp->st_mtx,
1939 sbt, precision, C_ABSOLUTE);
1940 else
1941 error = cv_wait_sig(&stp->st_wait, &stp->st_mtx);
1942 mtx_unlock(&stp->st_mtx);
1943
1944 return (error);
1945 }
1946
1947 void
1948 seltdfini(struct thread *td)
1949 {
1950 struct seltd *stp;
1951
1952 stp = td->td_sel;
1953 if (stp == NULL)
1954 return;
1955 MPASS(stp->st_flags == 0);
1956 MPASS(STAILQ_EMPTY(&stp->st_selq));
1957 if (stp->st_free1)
1958 free(stp->st_free1, M_SELFD);
1959 if (stp->st_free2)
1960 free(stp->st_free2, M_SELFD);
1961 td->td_sel = NULL;
1962 cv_destroy(&stp->st_wait);
1963 mtx_destroy(&stp->st_mtx);
1964 free(stp, M_SELECT);
1965 }
1966
1967 /*
1968 * Remove the references to the thread from all of the objects we were
1969 * polling.
1970 */
1971 static void
1972 seltdclear(struct thread *td)
1973 {
1974 struct seltd *stp;
1975 struct selfd *sfp;
1976 struct selfd *sfn;
1977
1978 stp = td->td_sel;
1979 STAILQ_FOREACH_SAFE(sfp, &stp->st_selq, sf_link, sfn)
1980 selfdfree(stp, sfp);
1981 stp->st_flags = 0;
1982 }
1983
1984 static void selectinit(void *);
1985 SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDER_ANY, selectinit, NULL);
1986 static void
1987 selectinit(void *dummy __unused)
1988 {
1989
1990 mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
1991 }
1992
1993 /*
1994 * Set up a syscall return value that follows the convention specified for
1995 * posix_* functions.
1996 */
1997 int
1998 kern_posix_error(struct thread *td, int error)
1999 {
2000
2001 if (error <= 0)
2002 return (error);
2003 td->td_errno = error;
2004 td->td_pflags |= TDP_NERRNO;
2005 td->td_retval[0] = error;
2006 return (0);
2007 }
Cache object: 412bce1ee0c3248b5d22d610b9dafbd5
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