1 /*-
2 * Copyright (c) 2013-2015 Gleb Smirnoff <glebius@FreeBSD.org>
3 * Copyright (c) 1998, David Greenman. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD: releng/12.0/sys/kern/kern_sendfile.c 339379 2018-10-16 15:57:16Z glebius $");
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/capsicum.h>
36 #include <sys/kernel.h>
37 #include <sys/lock.h>
38 #include <sys/mutex.h>
39 #include <sys/sysproto.h>
40 #include <sys/malloc.h>
41 #include <sys/proc.h>
42 #include <sys/mman.h>
43 #include <sys/mount.h>
44 #include <sys/mbuf.h>
45 #include <sys/protosw.h>
46 #include <sys/rwlock.h>
47 #include <sys/sf_buf.h>
48 #include <sys/socket.h>
49 #include <sys/socketvar.h>
50 #include <sys/syscallsubr.h>
51 #include <sys/sysctl.h>
52 #include <sys/vnode.h>
53
54 #include <net/vnet.h>
55
56 #include <security/audit/audit.h>
57 #include <security/mac/mac_framework.h>
58
59 #include <vm/vm.h>
60 #include <vm/vm_object.h>
61 #include <vm/vm_pager.h>
62
63 #define EXT_FLAG_SYNC EXT_FLAG_VENDOR1
64 #define EXT_FLAG_NOCACHE EXT_FLAG_VENDOR2
65
66 /*
67 * Structure describing a single sendfile(2) I/O, which may consist of
68 * several underlying pager I/Os.
69 *
70 * The syscall context allocates the structure and initializes 'nios'
71 * to 1. As sendfile_swapin() runs through pages and starts asynchronous
72 * paging operations, it increments 'nios'.
73 *
74 * Every I/O completion calls sendfile_iodone(), which decrements the 'nios',
75 * and the syscall also calls sendfile_iodone() after allocating all mbufs,
76 * linking them and sending to socket. Whoever reaches zero 'nios' is
77 * responsible to * call pru_ready on the socket, to notify it of readyness
78 * of the data.
79 */
80 struct sf_io {
81 volatile u_int nios;
82 u_int error;
83 int npages;
84 struct socket *so;
85 struct mbuf *m;
86 vm_page_t pa[];
87 };
88
89 /*
90 * Structure used to track requests with SF_SYNC flag.
91 */
92 struct sendfile_sync {
93 struct mtx mtx;
94 struct cv cv;
95 unsigned count;
96 };
97
98 counter_u64_t sfstat[sizeof(struct sfstat) / sizeof(uint64_t)];
99
100 static void
101 sfstat_init(const void *unused)
102 {
103
104 COUNTER_ARRAY_ALLOC(sfstat, sizeof(struct sfstat) / sizeof(uint64_t),
105 M_WAITOK);
106 }
107 SYSINIT(sfstat, SI_SUB_MBUF, SI_ORDER_FIRST, sfstat_init, NULL);
108
109 static int
110 sfstat_sysctl(SYSCTL_HANDLER_ARGS)
111 {
112 struct sfstat s;
113
114 COUNTER_ARRAY_COPY(sfstat, &s, sizeof(s) / sizeof(uint64_t));
115 if (req->newptr)
116 COUNTER_ARRAY_ZERO(sfstat, sizeof(s) / sizeof(uint64_t));
117 return (SYSCTL_OUT(req, &s, sizeof(s)));
118 }
119 SYSCTL_PROC(_kern_ipc, OID_AUTO, sfstat, CTLTYPE_OPAQUE | CTLFLAG_RW,
120 NULL, 0, sfstat_sysctl, "I", "sendfile statistics");
121
122 /*
123 * Detach mapped page and release resources back to the system. Called
124 * by mbuf(9) code when last reference to a page is freed.
125 */
126 static void
127 sendfile_free_page(vm_page_t pg, bool nocache)
128 {
129 bool freed;
130
131 vm_page_lock(pg);
132 /*
133 * In either case check for the object going away on us. This can
134 * happen since we don't hold a reference to it. If so, we're
135 * responsible for freeing the page. In 'noncache' case try to free
136 * the page, but only if it is cheap to.
137 */
138 if (vm_page_unwire_noq(pg)) {
139 vm_object_t obj;
140
141 if ((obj = pg->object) == NULL)
142 vm_page_free(pg);
143 else {
144 freed = false;
145 if (nocache && !vm_page_xbusied(pg) &&
146 VM_OBJECT_TRYWLOCK(obj)) {
147 /* Only free unmapped pages. */
148 if (obj->ref_count == 0 ||
149 !pmap_page_is_mapped(pg))
150 /*
151 * The busy test before the object is
152 * locked cannot be relied upon.
153 */
154 freed = vm_page_try_to_free(pg);
155 VM_OBJECT_WUNLOCK(obj);
156 }
157 if (!freed) {
158 /*
159 * If we were asked to not cache the page, place
160 * it near the head of the inactive queue so
161 * that it is reclaimed sooner. Otherwise,
162 * maintain LRU.
163 */
164 if (nocache)
165 vm_page_deactivate_noreuse(pg);
166 else if (vm_page_active(pg))
167 vm_page_reference(pg);
168 else
169 vm_page_deactivate(pg);
170 }
171 }
172 }
173 vm_page_unlock(pg);
174 }
175
176 static void
177 sendfile_free_mext(struct mbuf *m)
178 {
179 struct sf_buf *sf;
180 vm_page_t pg;
181 bool nocache;
182
183 KASSERT(m->m_flags & M_EXT && m->m_ext.ext_type == EXT_SFBUF,
184 ("%s: m %p !M_EXT or !EXT_SFBUF", __func__, m));
185
186 sf = m->m_ext.ext_arg1;
187 pg = sf_buf_page(sf);
188 nocache = m->m_ext.ext_flags & EXT_FLAG_NOCACHE;
189
190 sf_buf_free(sf);
191 sendfile_free_page(pg, nocache);
192
193 if (m->m_ext.ext_flags & EXT_FLAG_SYNC) {
194 struct sendfile_sync *sfs = m->m_ext.ext_arg2;
195
196 mtx_lock(&sfs->mtx);
197 KASSERT(sfs->count > 0, ("Sendfile sync botchup count == 0"));
198 if (--sfs->count == 0)
199 cv_signal(&sfs->cv);
200 mtx_unlock(&sfs->mtx);
201 }
202 }
203
204 /*
205 * Helper function to calculate how much data to put into page i of n.
206 * Only first and last pages are special.
207 */
208 static inline off_t
209 xfsize(int i, int n, off_t off, off_t len)
210 {
211
212 if (i == 0)
213 return (omin(PAGE_SIZE - (off & PAGE_MASK), len));
214
215 if (i == n - 1 && ((off + len) & PAGE_MASK) > 0)
216 return ((off + len) & PAGE_MASK);
217
218 return (PAGE_SIZE);
219 }
220
221 /*
222 * Helper function to get offset within object for i page.
223 */
224 static inline vm_ooffset_t
225 vmoff(int i, off_t off)
226 {
227
228 if (i == 0)
229 return ((vm_ooffset_t)off);
230
231 return (trunc_page(off + i * PAGE_SIZE));
232 }
233
234 /*
235 * Helper function used when allocation of a page or sf_buf failed.
236 * Pretend as if we don't have enough space, subtract xfsize() of
237 * all pages that failed.
238 */
239 static inline void
240 fixspace(int old, int new, off_t off, int *space)
241 {
242
243 KASSERT(old > new, ("%s: old %d new %d", __func__, old, new));
244
245 /* Subtract last one. */
246 *space -= xfsize(old - 1, old, off, *space);
247 old--;
248
249 if (new == old)
250 /* There was only one page. */
251 return;
252
253 /* Subtract first one. */
254 if (new == 0) {
255 *space -= xfsize(0, old, off, *space);
256 new++;
257 }
258
259 /* Rest of pages are full sized. */
260 *space -= (old - new) * PAGE_SIZE;
261
262 KASSERT(*space >= 0, ("%s: space went backwards", __func__));
263 }
264
265 /*
266 * I/O completion callback.
267 */
268 static void
269 sendfile_iodone(void *arg, vm_page_t *pg, int count, int error)
270 {
271 struct sf_io *sfio = arg;
272 struct socket *so = sfio->so;
273
274 for (int i = 0; i < count; i++)
275 if (pg[i] != bogus_page)
276 vm_page_xunbusy(pg[i]);
277
278 if (error)
279 sfio->error = error;
280
281 if (!refcount_release(&sfio->nios))
282 return;
283
284 CURVNET_SET(so->so_vnet);
285 if (sfio->error) {
286 struct mbuf *m;
287
288 /*
289 * I/O operation failed. The state of data in the socket
290 * is now inconsistent, and all what we can do is to tear
291 * it down. Protocol abort method would tear down protocol
292 * state, free all ready mbufs and detach not ready ones.
293 * We will free the mbufs corresponding to this I/O manually.
294 *
295 * The socket would be marked with EIO and made available
296 * for read, so that application receives EIO on next
297 * syscall and eventually closes the socket.
298 */
299 so->so_proto->pr_usrreqs->pru_abort(so);
300 so->so_error = EIO;
301
302 m = sfio->m;
303 for (int i = 0; i < sfio->npages; i++)
304 m = m_free(m);
305 } else
306 (void )(so->so_proto->pr_usrreqs->pru_ready)(so, sfio->m,
307 sfio->npages);
308
309 SOCK_LOCK(so);
310 sorele(so);
311 CURVNET_RESTORE();
312 free(sfio, M_TEMP);
313 }
314
315 /*
316 * Iterate through pages vector and request paging for non-valid pages.
317 */
318 static int
319 sendfile_swapin(vm_object_t obj, struct sf_io *sfio, off_t off, off_t len,
320 int npages, int rhpages, int flags)
321 {
322 vm_page_t *pa = sfio->pa;
323 int grabbed, nios;
324
325 nios = 0;
326 flags = (flags & SF_NODISKIO) ? VM_ALLOC_NOWAIT : 0;
327
328 /*
329 * First grab all the pages and wire them. Note that we grab
330 * only required pages. Readahead pages are dealt with later.
331 */
332 VM_OBJECT_WLOCK(obj);
333
334 grabbed = vm_page_grab_pages(obj, OFF_TO_IDX(off),
335 VM_ALLOC_NORMAL | VM_ALLOC_WIRED | flags, pa, npages);
336 if (grabbed < npages) {
337 for (int i = grabbed; i < npages; i++)
338 pa[i] = NULL;
339 npages = grabbed;
340 rhpages = 0;
341 }
342
343 for (int i = 0; i < npages;) {
344 int j, a, count, rv __unused;
345
346 /* Skip valid pages. */
347 if (vm_page_is_valid(pa[i], vmoff(i, off) & PAGE_MASK,
348 xfsize(i, npages, off, len))) {
349 vm_page_xunbusy(pa[i]);
350 SFSTAT_INC(sf_pages_valid);
351 i++;
352 continue;
353 }
354
355 /*
356 * Next page is invalid. Check if it belongs to pager. It
357 * may not be there, which is a regular situation for shmem
358 * pager. For vnode pager this happens only in case of
359 * a sparse file.
360 *
361 * Important feature of vm_pager_has_page() is the hint
362 * stored in 'a', about how many pages we can pagein after
363 * this page in a single I/O.
364 */
365 if (!vm_pager_has_page(obj, OFF_TO_IDX(vmoff(i, off)), NULL,
366 &a)) {
367 pmap_zero_page(pa[i]);
368 pa[i]->valid = VM_PAGE_BITS_ALL;
369 MPASS(pa[i]->dirty == 0);
370 vm_page_xunbusy(pa[i]);
371 i++;
372 continue;
373 }
374
375 /*
376 * We want to pagein as many pages as possible, limited only
377 * by the 'a' hint and actual request.
378 */
379 count = min(a + 1, npages - i);
380
381 /*
382 * We should not pagein into a valid page, thus we first trim
383 * any valid pages off the end of request, and substitute
384 * to bogus_page those, that are in the middle.
385 */
386 for (j = i + count - 1; j > i; j--) {
387 if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK,
388 xfsize(j, npages, off, len))) {
389 count--;
390 rhpages = 0;
391 } else
392 break;
393 }
394 for (j = i + 1; j < i + count - 1; j++)
395 if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK,
396 xfsize(j, npages, off, len))) {
397 vm_page_xunbusy(pa[j]);
398 SFSTAT_INC(sf_pages_valid);
399 SFSTAT_INC(sf_pages_bogus);
400 pa[j] = bogus_page;
401 }
402
403 refcount_acquire(&sfio->nios);
404 rv = vm_pager_get_pages_async(obj, pa + i, count, NULL,
405 i + count == npages ? &rhpages : NULL,
406 &sendfile_iodone, sfio);
407 KASSERT(rv == VM_PAGER_OK, ("%s: pager fail obj %p page %p",
408 __func__, obj, pa[i]));
409
410 SFSTAT_INC(sf_iocnt);
411 SFSTAT_ADD(sf_pages_read, count);
412 if (i + count == npages)
413 SFSTAT_ADD(sf_rhpages_read, rhpages);
414
415 /*
416 * Restore the valid page pointers. They are already
417 * unbusied, but still wired.
418 */
419 for (j = i; j < i + count; j++)
420 if (pa[j] == bogus_page) {
421 pa[j] = vm_page_lookup(obj,
422 OFF_TO_IDX(vmoff(j, off)));
423 KASSERT(pa[j], ("%s: page %p[%d] disappeared",
424 __func__, pa, j));
425
426 }
427 i += count;
428 nios++;
429 }
430
431 VM_OBJECT_WUNLOCK(obj);
432
433 if (nios == 0 && npages != 0)
434 SFSTAT_INC(sf_noiocnt);
435
436 return (nios);
437 }
438
439 static int
440 sendfile_getobj(struct thread *td, struct file *fp, vm_object_t *obj_res,
441 struct vnode **vp_res, struct shmfd **shmfd_res, off_t *obj_size,
442 int *bsize)
443 {
444 struct vattr va;
445 vm_object_t obj;
446 struct vnode *vp;
447 struct shmfd *shmfd;
448 int error;
449
450 vp = *vp_res = NULL;
451 obj = NULL;
452 shmfd = *shmfd_res = NULL;
453 *bsize = 0;
454
455 /*
456 * The file descriptor must be a regular file and have a
457 * backing VM object.
458 */
459 if (fp->f_type == DTYPE_VNODE) {
460 vp = fp->f_vnode;
461 vn_lock(vp, LK_SHARED | LK_RETRY);
462 if (vp->v_type != VREG) {
463 error = EINVAL;
464 goto out;
465 }
466 *bsize = vp->v_mount->mnt_stat.f_iosize;
467 error = VOP_GETATTR(vp, &va, td->td_ucred);
468 if (error != 0)
469 goto out;
470 *obj_size = va.va_size;
471 obj = vp->v_object;
472 if (obj == NULL) {
473 error = EINVAL;
474 goto out;
475 }
476 } else if (fp->f_type == DTYPE_SHM) {
477 error = 0;
478 shmfd = fp->f_data;
479 obj = shmfd->shm_object;
480 *obj_size = shmfd->shm_size;
481 } else {
482 error = EINVAL;
483 goto out;
484 }
485
486 VM_OBJECT_WLOCK(obj);
487 if ((obj->flags & OBJ_DEAD) != 0) {
488 VM_OBJECT_WUNLOCK(obj);
489 error = EBADF;
490 goto out;
491 }
492
493 /*
494 * Temporarily increase the backing VM object's reference
495 * count so that a forced reclamation of its vnode does not
496 * immediately destroy it.
497 */
498 vm_object_reference_locked(obj);
499 VM_OBJECT_WUNLOCK(obj);
500 *obj_res = obj;
501 *vp_res = vp;
502 *shmfd_res = shmfd;
503
504 out:
505 if (vp != NULL)
506 VOP_UNLOCK(vp, 0);
507 return (error);
508 }
509
510 static int
511 sendfile_getsock(struct thread *td, int s, struct file **sock_fp,
512 struct socket **so)
513 {
514 int error;
515
516 *sock_fp = NULL;
517 *so = NULL;
518
519 /*
520 * The socket must be a stream socket and connected.
521 */
522 error = getsock_cap(td, s, &cap_send_rights,
523 sock_fp, NULL, NULL);
524 if (error != 0)
525 return (error);
526 *so = (*sock_fp)->f_data;
527 if ((*so)->so_type != SOCK_STREAM)
528 return (EINVAL);
529 if (SOLISTENING(*so))
530 return (ENOTCONN);
531 return (0);
532 }
533
534 int
535 vn_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio,
536 struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags,
537 struct thread *td)
538 {
539 struct file *sock_fp;
540 struct vnode *vp;
541 struct vm_object *obj;
542 struct socket *so;
543 struct mbuf *m, *mh, *mhtail;
544 struct sf_buf *sf;
545 struct shmfd *shmfd;
546 struct sendfile_sync *sfs;
547 struct vattr va;
548 off_t off, sbytes, rem, obj_size;
549 int error, softerr, bsize, hdrlen;
550
551 obj = NULL;
552 so = NULL;
553 m = mh = NULL;
554 sfs = NULL;
555 hdrlen = sbytes = 0;
556 softerr = 0;
557
558 error = sendfile_getobj(td, fp, &obj, &vp, &shmfd, &obj_size, &bsize);
559 if (error != 0)
560 return (error);
561
562 error = sendfile_getsock(td, sockfd, &sock_fp, &so);
563 if (error != 0)
564 goto out;
565
566 #ifdef MAC
567 error = mac_socket_check_send(td->td_ucred, so);
568 if (error != 0)
569 goto out;
570 #endif
571
572 SFSTAT_INC(sf_syscalls);
573 SFSTAT_ADD(sf_rhpages_requested, SF_READAHEAD(flags));
574
575 if (flags & SF_SYNC) {
576 sfs = malloc(sizeof *sfs, M_TEMP, M_WAITOK | M_ZERO);
577 mtx_init(&sfs->mtx, "sendfile", NULL, MTX_DEF);
578 cv_init(&sfs->cv, "sendfile");
579 }
580
581 rem = nbytes ? omin(nbytes, obj_size - offset) : obj_size - offset;
582
583 /*
584 * Protect against multiple writers to the socket.
585 *
586 * XXXRW: Historically this has assumed non-interruptibility, so now
587 * we implement that, but possibly shouldn't.
588 */
589 (void)sblock(&so->so_snd, SBL_WAIT | SBL_NOINTR);
590
591 /*
592 * Loop through the pages of the file, starting with the requested
593 * offset. Get a file page (do I/O if necessary), map the file page
594 * into an sf_buf, attach an mbuf header to the sf_buf, and queue
595 * it on the socket.
596 * This is done in two loops. The inner loop turns as many pages
597 * as it can, up to available socket buffer space, without blocking
598 * into mbufs to have it bulk delivered into the socket send buffer.
599 * The outer loop checks the state and available space of the socket
600 * and takes care of the overall progress.
601 */
602 for (off = offset; rem > 0; ) {
603 struct sf_io *sfio;
604 vm_page_t *pa;
605 struct mbuf *mtail;
606 int nios, space, npages, rhpages;
607
608 mtail = NULL;
609 /*
610 * Check the socket state for ongoing connection,
611 * no errors and space in socket buffer.
612 * If space is low allow for the remainder of the
613 * file to be processed if it fits the socket buffer.
614 * Otherwise block in waiting for sufficient space
615 * to proceed, or if the socket is nonblocking, return
616 * to userland with EAGAIN while reporting how far
617 * we've come.
618 * We wait until the socket buffer has significant free
619 * space to do bulk sends. This makes good use of file
620 * system read ahead and allows packet segmentation
621 * offloading hardware to take over lots of work. If
622 * we were not careful here we would send off only one
623 * sfbuf at a time.
624 */
625 SOCKBUF_LOCK(&so->so_snd);
626 if (so->so_snd.sb_lowat < so->so_snd.sb_hiwat / 2)
627 so->so_snd.sb_lowat = so->so_snd.sb_hiwat / 2;
628 retry_space:
629 if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
630 error = EPIPE;
631 SOCKBUF_UNLOCK(&so->so_snd);
632 goto done;
633 } else if (so->so_error) {
634 error = so->so_error;
635 so->so_error = 0;
636 SOCKBUF_UNLOCK(&so->so_snd);
637 goto done;
638 }
639 if ((so->so_state & SS_ISCONNECTED) == 0) {
640 SOCKBUF_UNLOCK(&so->so_snd);
641 error = ENOTCONN;
642 goto done;
643 }
644
645 space = sbspace(&so->so_snd);
646 if (space < rem &&
647 (space <= 0 ||
648 space < so->so_snd.sb_lowat)) {
649 if (so->so_state & SS_NBIO) {
650 SOCKBUF_UNLOCK(&so->so_snd);
651 error = EAGAIN;
652 goto done;
653 }
654 /*
655 * sbwait drops the lock while sleeping.
656 * When we loop back to retry_space the
657 * state may have changed and we retest
658 * for it.
659 */
660 error = sbwait(&so->so_snd);
661 /*
662 * An error from sbwait usually indicates that we've
663 * been interrupted by a signal. If we've sent anything
664 * then return bytes sent, otherwise return the error.
665 */
666 if (error != 0) {
667 SOCKBUF_UNLOCK(&so->so_snd);
668 goto done;
669 }
670 goto retry_space;
671 }
672 SOCKBUF_UNLOCK(&so->so_snd);
673
674 /*
675 * At the beginning of the first loop check if any headers
676 * are specified and copy them into mbufs. Reduce space in
677 * the socket buffer by the size of the header mbuf chain.
678 * Clear hdr_uio here and hdrlen at the end of the first loop.
679 */
680 if (hdr_uio != NULL && hdr_uio->uio_resid > 0) {
681 hdr_uio->uio_td = td;
682 hdr_uio->uio_rw = UIO_WRITE;
683 mh = m_uiotombuf(hdr_uio, M_WAITOK, space, 0, 0);
684 hdrlen = m_length(mh, &mhtail);
685 space -= hdrlen;
686 /*
687 * If header consumed all the socket buffer space,
688 * don't waste CPU cycles and jump to the end.
689 */
690 if (space == 0) {
691 sfio = NULL;
692 nios = 0;
693 goto prepend_header;
694 }
695 hdr_uio = NULL;
696 }
697
698 if (vp != NULL) {
699 error = vn_lock(vp, LK_SHARED);
700 if (error != 0)
701 goto done;
702 error = VOP_GETATTR(vp, &va, td->td_ucred);
703 if (error != 0 || off >= va.va_size) {
704 VOP_UNLOCK(vp, 0);
705 goto done;
706 }
707 if (va.va_size != obj_size) {
708 obj_size = va.va_size;
709 rem = nbytes ?
710 omin(nbytes + offset, obj_size) : obj_size;
711 rem -= off;
712 }
713 }
714
715 if (space > rem)
716 space = rem;
717
718 npages = howmany(space + (off & PAGE_MASK), PAGE_SIZE);
719
720 /*
721 * Calculate maximum allowed number of pages for readahead
722 * at this iteration. If SF_USER_READAHEAD was set, we don't
723 * do any heuristics and use exactly the value supplied by
724 * application. Otherwise, we allow readahead up to "rem".
725 * If application wants more, let it be, but there is no
726 * reason to go above MAXPHYS. Also check against "obj_size",
727 * since vm_pager_has_page() can hint beyond EOF.
728 */
729 if (flags & SF_USER_READAHEAD) {
730 rhpages = SF_READAHEAD(flags);
731 } else {
732 rhpages = howmany(rem + (off & PAGE_MASK), PAGE_SIZE) -
733 npages;
734 rhpages += SF_READAHEAD(flags);
735 }
736 rhpages = min(howmany(MAXPHYS, PAGE_SIZE), rhpages);
737 rhpages = min(howmany(obj_size - trunc_page(off), PAGE_SIZE) -
738 npages, rhpages);
739
740 sfio = malloc(sizeof(struct sf_io) +
741 npages * sizeof(vm_page_t), M_TEMP, M_WAITOK);
742 refcount_init(&sfio->nios, 1);
743 sfio->so = so;
744 sfio->error = 0;
745
746 nios = sendfile_swapin(obj, sfio, off, space, npages, rhpages,
747 flags);
748
749 /*
750 * Loop and construct maximum sized mbuf chain to be bulk
751 * dumped into socket buffer.
752 */
753 pa = sfio->pa;
754 for (int i = 0; i < npages; i++) {
755 struct mbuf *m0;
756
757 /*
758 * If a page wasn't grabbed successfully, then
759 * trim the array. Can happen only with SF_NODISKIO.
760 */
761 if (pa[i] == NULL) {
762 SFSTAT_INC(sf_busy);
763 fixspace(npages, i, off, &space);
764 npages = i;
765 softerr = EBUSY;
766 break;
767 }
768
769 /*
770 * Get a sendfile buf. When allocating the
771 * first buffer for mbuf chain, we usually
772 * wait as long as necessary, but this wait
773 * can be interrupted. For consequent
774 * buffers, do not sleep, since several
775 * threads might exhaust the buffers and then
776 * deadlock.
777 */
778 sf = sf_buf_alloc(pa[i],
779 m != NULL ? SFB_NOWAIT : SFB_CATCH);
780 if (sf == NULL) {
781 SFSTAT_INC(sf_allocfail);
782 for (int j = i; j < npages; j++) {
783 vm_page_lock(pa[j]);
784 vm_page_unwire(pa[j], PQ_INACTIVE);
785 vm_page_unlock(pa[j]);
786 }
787 if (m == NULL)
788 softerr = ENOBUFS;
789 fixspace(npages, i, off, &space);
790 npages = i;
791 break;
792 }
793
794 m0 = m_get(M_WAITOK, MT_DATA);
795 m0->m_ext.ext_buf = (char *)sf_buf_kva(sf);
796 m0->m_ext.ext_size = PAGE_SIZE;
797 m0->m_ext.ext_arg1 = sf;
798 m0->m_ext.ext_type = EXT_SFBUF;
799 m0->m_ext.ext_flags = EXT_FLAG_EMBREF;
800 m0->m_ext.ext_free = sendfile_free_mext;
801 /*
802 * SF_NOCACHE sets the page as being freed upon send.
803 * However, we ignore it for the last page in 'space',
804 * if the page is truncated, and we got more data to
805 * send (rem > space), or if we have readahead
806 * configured (rhpages > 0).
807 */
808 if ((flags & SF_NOCACHE) &&
809 (i != npages - 1 ||
810 !((off + space) & PAGE_MASK) ||
811 !(rem > space || rhpages > 0)))
812 m0->m_ext.ext_flags |= EXT_FLAG_NOCACHE;
813 if (sfs != NULL) {
814 m0->m_ext.ext_flags |= EXT_FLAG_SYNC;
815 m0->m_ext.ext_arg2 = sfs;
816 mtx_lock(&sfs->mtx);
817 sfs->count++;
818 mtx_unlock(&sfs->mtx);
819 }
820 m0->m_ext.ext_count = 1;
821 m0->m_flags |= (M_EXT | M_RDONLY);
822 if (nios)
823 m0->m_flags |= M_NOTREADY;
824 m0->m_data = (char *)sf_buf_kva(sf) +
825 (vmoff(i, off) & PAGE_MASK);
826 m0->m_len = xfsize(i, npages, off, space);
827
828 if (i == 0)
829 sfio->m = m0;
830
831 /* Append to mbuf chain. */
832 if (mtail != NULL)
833 mtail->m_next = m0;
834 else
835 m = m0;
836 mtail = m0;
837 }
838
839 if (vp != NULL)
840 VOP_UNLOCK(vp, 0);
841
842 /* Keep track of bytes processed. */
843 off += space;
844 rem -= space;
845
846 /* Prepend header, if any. */
847 if (hdrlen) {
848 prepend_header:
849 mhtail->m_next = m;
850 m = mh;
851 mh = NULL;
852 }
853
854 if (m == NULL) {
855 KASSERT(softerr, ("%s: m NULL, no error", __func__));
856 error = softerr;
857 free(sfio, M_TEMP);
858 goto done;
859 }
860
861 /* Add the buffer chain to the socket buffer. */
862 KASSERT(m_length(m, NULL) == space + hdrlen,
863 ("%s: mlen %u space %d hdrlen %d",
864 __func__, m_length(m, NULL), space, hdrlen));
865
866 CURVNET_SET(so->so_vnet);
867 if (nios == 0) {
868 /*
869 * If sendfile_swapin() didn't initiate any I/Os,
870 * which happens if all data is cached in VM, then
871 * we can send data right now without the
872 * PRUS_NOTREADY flag.
873 */
874 free(sfio, M_TEMP);
875 error = (*so->so_proto->pr_usrreqs->pru_send)
876 (so, 0, m, NULL, NULL, td);
877 } else {
878 sfio->npages = npages;
879 soref(so);
880 error = (*so->so_proto->pr_usrreqs->pru_send)
881 (so, PRUS_NOTREADY, m, NULL, NULL, td);
882 sendfile_iodone(sfio, NULL, 0, 0);
883 }
884 CURVNET_RESTORE();
885
886 m = NULL; /* pru_send always consumes */
887 if (error)
888 goto done;
889 sbytes += space + hdrlen;
890 if (hdrlen)
891 hdrlen = 0;
892 if (softerr) {
893 error = softerr;
894 goto done;
895 }
896 }
897
898 /*
899 * Send trailers. Wimp out and use writev(2).
900 */
901 if (trl_uio != NULL) {
902 sbunlock(&so->so_snd);
903 error = kern_writev(td, sockfd, trl_uio);
904 if (error == 0)
905 sbytes += td->td_retval[0];
906 goto out;
907 }
908
909 done:
910 sbunlock(&so->so_snd);
911 out:
912 /*
913 * If there was no error we have to clear td->td_retval[0]
914 * because it may have been set by writev.
915 */
916 if (error == 0) {
917 td->td_retval[0] = 0;
918 }
919 if (sent != NULL) {
920 (*sent) = sbytes;
921 }
922 if (obj != NULL)
923 vm_object_deallocate(obj);
924 if (so)
925 fdrop(sock_fp, td);
926 if (m)
927 m_freem(m);
928 if (mh)
929 m_freem(mh);
930
931 if (sfs != NULL) {
932 mtx_lock(&sfs->mtx);
933 if (sfs->count != 0)
934 cv_wait(&sfs->cv, &sfs->mtx);
935 KASSERT(sfs->count == 0, ("sendfile sync still busy"));
936 cv_destroy(&sfs->cv);
937 mtx_destroy(&sfs->mtx);
938 free(sfs, M_TEMP);
939 }
940
941 if (error == ERESTART)
942 error = EINTR;
943
944 return (error);
945 }
946
947 static int
948 sendfile(struct thread *td, struct sendfile_args *uap, int compat)
949 {
950 struct sf_hdtr hdtr;
951 struct uio *hdr_uio, *trl_uio;
952 struct file *fp;
953 off_t sbytes;
954 int error;
955
956 /*
957 * File offset must be positive. If it goes beyond EOF
958 * we send only the header/trailer and no payload data.
959 */
960 if (uap->offset < 0)
961 return (EINVAL);
962
963 sbytes = 0;
964 hdr_uio = trl_uio = NULL;
965
966 if (uap->hdtr != NULL) {
967 error = copyin(uap->hdtr, &hdtr, sizeof(hdtr));
968 if (error != 0)
969 goto out;
970 if (hdtr.headers != NULL) {
971 error = copyinuio(hdtr.headers, hdtr.hdr_cnt,
972 &hdr_uio);
973 if (error != 0)
974 goto out;
975 #ifdef COMPAT_FREEBSD4
976 /*
977 * In FreeBSD < 5.0 the nbytes to send also included
978 * the header. If compat is specified subtract the
979 * header size from nbytes.
980 */
981 if (compat) {
982 if (uap->nbytes > hdr_uio->uio_resid)
983 uap->nbytes -= hdr_uio->uio_resid;
984 else
985 uap->nbytes = 0;
986 }
987 #endif
988 }
989 if (hdtr.trailers != NULL) {
990 error = copyinuio(hdtr.trailers, hdtr.trl_cnt,
991 &trl_uio);
992 if (error != 0)
993 goto out;
994 }
995 }
996
997 AUDIT_ARG_FD(uap->fd);
998
999 /*
1000 * sendfile(2) can start at any offset within a file so we require
1001 * CAP_READ+CAP_SEEK = CAP_PREAD.
1002 */
1003 if ((error = fget_read(td, uap->fd, &cap_pread_rights, &fp)) != 0)
1004 goto out;
1005
1006 error = fo_sendfile(fp, uap->s, hdr_uio, trl_uio, uap->offset,
1007 uap->nbytes, &sbytes, uap->flags, td);
1008 fdrop(fp, td);
1009
1010 if (uap->sbytes != NULL)
1011 copyout(&sbytes, uap->sbytes, sizeof(off_t));
1012
1013 out:
1014 free(hdr_uio, M_IOV);
1015 free(trl_uio, M_IOV);
1016 return (error);
1017 }
1018
1019 /*
1020 * sendfile(2)
1021 *
1022 * int sendfile(int fd, int s, off_t offset, size_t nbytes,
1023 * struct sf_hdtr *hdtr, off_t *sbytes, int flags)
1024 *
1025 * Send a file specified by 'fd' and starting at 'offset' to a socket
1026 * specified by 's'. Send only 'nbytes' of the file or until EOF if nbytes ==
1027 * 0. Optionally add a header and/or trailer to the socket output. If
1028 * specified, write the total number of bytes sent into *sbytes.
1029 */
1030 int
1031 sys_sendfile(struct thread *td, struct sendfile_args *uap)
1032 {
1033
1034 return (sendfile(td, uap, 0));
1035 }
1036
1037 #ifdef COMPAT_FREEBSD4
1038 int
1039 freebsd4_sendfile(struct thread *td, struct freebsd4_sendfile_args *uap)
1040 {
1041 struct sendfile_args args;
1042
1043 args.fd = uap->fd;
1044 args.s = uap->s;
1045 args.offset = uap->offset;
1046 args.nbytes = uap->nbytes;
1047 args.hdtr = uap->hdtr;
1048 args.sbytes = uap->sbytes;
1049 args.flags = uap->flags;
1050
1051 return (sendfile(td, &args, 1));
1052 }
1053 #endif /* COMPAT_FREEBSD4 */
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