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("$FreeBSD$");
32
33 #include "opt_kern_tls.h"
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/capsicum.h>
38 #include <sys/kernel.h>
39 #include <sys/lock.h>
40 #include <sys/ktls.h>
41 #include <sys/mutex.h>
42 #include <sys/malloc.h>
43 #include <sys/mman.h>
44 #include <sys/mount.h>
45 #include <sys/mbuf.h>
46 #include <sys/proc.h>
47 #include <sys/protosw.h>
48 #include <sys/rwlock.h>
49 #include <sys/sf_buf.h>
50 #include <sys/socket.h>
51 #include <sys/socketvar.h>
52 #include <sys/syscallsubr.h>
53 #include <sys/sysctl.h>
54 #include <sys/sysproto.h>
55 #include <sys/vnode.h>
56
57 #include <net/vnet.h>
58 #include <netinet/in.h>
59 #include <netinet/tcp.h>
60
61 #include <security/audit/audit.h>
62 #include <security/mac/mac_framework.h>
63
64 #include <vm/vm.h>
65 #include <vm/vm_object.h>
66 #include <vm/vm_pager.h>
67
68 static MALLOC_DEFINE(M_SENDFILE, "sendfile", "sendfile dynamic memory");
69
70 #define EXT_FLAG_SYNC EXT_FLAG_VENDOR1
71 #define EXT_FLAG_NOCACHE EXT_FLAG_VENDOR2
72 #define EXT_FLAG_CACHE_LAST EXT_FLAG_VENDOR3
73
74 /*
75 * Structure describing a single sendfile(2) I/O, which may consist of
76 * several underlying pager I/Os.
77 *
78 * The syscall context allocates the structure and initializes 'nios'
79 * to 1. As sendfile_swapin() runs through pages and starts asynchronous
80 * paging operations, it increments 'nios'.
81 *
82 * Every I/O completion calls sendfile_iodone(), which decrements the 'nios',
83 * and the syscall also calls sendfile_iodone() after allocating all mbufs,
84 * linking them and sending to socket. Whoever reaches zero 'nios' is
85 * responsible to * call pru_ready on the socket, to notify it of readyness
86 * of the data.
87 */
88 struct sf_io {
89 volatile u_int nios;
90 u_int error;
91 int npages;
92 struct socket *so;
93 struct mbuf *m;
94 vm_object_t obj;
95 vm_pindex_t pindex0;
96 #ifdef KERN_TLS
97 struct ktls_session *tls;
98 #endif
99 vm_page_t pa[];
100 };
101
102 /*
103 * Structure used to track requests with SF_SYNC flag.
104 */
105 struct sendfile_sync {
106 struct mtx mtx;
107 struct cv cv;
108 unsigned count;
109 bool waiting;
110 };
111
112 static void
113 sendfile_sync_destroy(struct sendfile_sync *sfs)
114 {
115 KASSERT(sfs->count == 0, ("sendfile sync %p still busy", sfs));
116
117 cv_destroy(&sfs->cv);
118 mtx_destroy(&sfs->mtx);
119 free(sfs, M_SENDFILE);
120 }
121
122 static void
123 sendfile_sync_signal(struct sendfile_sync *sfs)
124 {
125 mtx_lock(&sfs->mtx);
126 KASSERT(sfs->count > 0, ("sendfile sync %p not busy", sfs));
127 if (--sfs->count == 0) {
128 if (!sfs->waiting) {
129 /* The sendfile() waiter was interrupted by a signal. */
130 sendfile_sync_destroy(sfs);
131 return;
132 } else {
133 cv_signal(&sfs->cv);
134 }
135 }
136 mtx_unlock(&sfs->mtx);
137 }
138
139 counter_u64_t sfstat[sizeof(struct sfstat) / sizeof(uint64_t)];
140
141 static void
142 sfstat_init(const void *unused)
143 {
144
145 COUNTER_ARRAY_ALLOC(sfstat, sizeof(struct sfstat) / sizeof(uint64_t),
146 M_WAITOK);
147 }
148 SYSINIT(sfstat, SI_SUB_MBUF, SI_ORDER_FIRST, sfstat_init, NULL);
149
150 static int
151 sfstat_sysctl(SYSCTL_HANDLER_ARGS)
152 {
153 struct sfstat s;
154
155 COUNTER_ARRAY_COPY(sfstat, &s, sizeof(s) / sizeof(uint64_t));
156 if (req->newptr)
157 COUNTER_ARRAY_ZERO(sfstat, sizeof(s) / sizeof(uint64_t));
158 return (SYSCTL_OUT(req, &s, sizeof(s)));
159 }
160 SYSCTL_PROC(_kern_ipc, OID_AUTO, sfstat,
161 CTLTYPE_OPAQUE | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0,
162 sfstat_sysctl, "I",
163 "sendfile statistics");
164
165 static void
166 sendfile_free_mext(struct mbuf *m)
167 {
168 struct sf_buf *sf;
169 vm_page_t pg;
170 int flags;
171
172 KASSERT(m->m_flags & M_EXT && m->m_ext.ext_type == EXT_SFBUF,
173 ("%s: m %p !M_EXT or !EXT_SFBUF", __func__, m));
174
175 sf = m->m_ext.ext_arg1;
176 pg = sf_buf_page(sf);
177 flags = (m->m_ext.ext_flags & EXT_FLAG_NOCACHE) != 0 ? VPR_TRYFREE : 0;
178
179 sf_buf_free(sf);
180 vm_page_release(pg, flags);
181
182 if (m->m_ext.ext_flags & EXT_FLAG_SYNC) {
183 struct sendfile_sync *sfs = m->m_ext.ext_arg2;
184 sendfile_sync_signal(sfs);
185 }
186 }
187
188 static void
189 sendfile_free_mext_pg(struct mbuf *m)
190 {
191 vm_page_t pg;
192 int flags, i;
193 bool cache_last;
194
195 M_ASSERTEXTPG(m);
196
197 cache_last = m->m_ext.ext_flags & EXT_FLAG_CACHE_LAST;
198 flags = (m->m_ext.ext_flags & EXT_FLAG_NOCACHE) != 0 ? VPR_TRYFREE : 0;
199
200 for (i = 0; i < m->m_epg_npgs; i++) {
201 if (cache_last && i == m->m_epg_npgs - 1)
202 flags = 0;
203 pg = PHYS_TO_VM_PAGE(m->m_epg_pa[i]);
204 vm_page_release(pg, flags);
205 }
206
207 if (m->m_ext.ext_flags & EXT_FLAG_SYNC) {
208 struct sendfile_sync *sfs = m->m_ext.ext_arg1;
209 sendfile_sync_signal(sfs);
210 }
211 }
212
213 /*
214 * Helper function to calculate how much data to put into page i of n.
215 * Only first and last pages are special.
216 */
217 static inline off_t
218 xfsize(int i, int n, off_t off, off_t len)
219 {
220
221 if (i == 0)
222 return (omin(PAGE_SIZE - (off & PAGE_MASK), len));
223
224 if (i == n - 1 && ((off + len) & PAGE_MASK) > 0)
225 return ((off + len) & PAGE_MASK);
226
227 return (PAGE_SIZE);
228 }
229
230 /*
231 * Helper function to get offset within object for i page.
232 */
233 static inline vm_ooffset_t
234 vmoff(int i, off_t off)
235 {
236
237 if (i == 0)
238 return ((vm_ooffset_t)off);
239
240 return (trunc_page(off + i * PAGE_SIZE));
241 }
242
243 /*
244 * Helper function used when allocation of a page or sf_buf failed.
245 * Pretend as if we don't have enough space, subtract xfsize() of
246 * all pages that failed.
247 */
248 static inline void
249 fixspace(int old, int new, off_t off, int *space)
250 {
251
252 KASSERT(old > new, ("%s: old %d new %d", __func__, old, new));
253
254 /* Subtract last one. */
255 *space -= xfsize(old - 1, old, off, *space);
256 old--;
257
258 if (new == old)
259 /* There was only one page. */
260 return;
261
262 /* Subtract first one. */
263 if (new == 0) {
264 *space -= xfsize(0, old, off, *space);
265 new++;
266 }
267
268 /* Rest of pages are full sized. */
269 *space -= (old - new) * PAGE_SIZE;
270
271 KASSERT(*space >= 0, ("%s: space went backwards", __func__));
272 }
273
274 /*
275 * Wait for all in-flight ios to complete, we must not unwire pages
276 * under them.
277 */
278 static void
279 sendfile_iowait(struct sf_io *sfio, const char *wmesg)
280 {
281 while (atomic_load_int(&sfio->nios) != 1)
282 pause(wmesg, 1);
283 }
284
285 /*
286 * I/O completion callback.
287 */
288 static void
289 sendfile_iodone(void *arg, vm_page_t *pa, int count, int error)
290 {
291 struct sf_io *sfio = arg;
292 struct socket *so;
293 int i;
294
295 if (error != 0)
296 sfio->error = error;
297
298 /*
299 * Restore the valid page pointers. They are already
300 * unbusied, but still wired.
301 *
302 * XXXKIB since pages are only wired, and we do not
303 * own the object lock, other users might have
304 * invalidated them in meantime. Similarly, after we
305 * unbusied the swapped-in pages, they can become
306 * invalid under us.
307 */
308 MPASS(count == 0 || pa[0] != bogus_page);
309 for (i = 0; i < count; i++) {
310 if (pa[i] == bogus_page) {
311 sfio->pa[(pa[0]->pindex - sfio->pindex0) + i] =
312 pa[i] = vm_page_relookup(sfio->obj,
313 pa[0]->pindex + i);
314 KASSERT(pa[i] != NULL,
315 ("%s: page %p[%d] disappeared",
316 __func__, pa, i));
317 } else {
318 vm_page_xunbusy_unchecked(pa[i]);
319 }
320 }
321
322 if (!refcount_release(&sfio->nios))
323 return;
324
325 #ifdef INVARIANTS
326 for (i = 1; i < sfio->npages; i++) {
327 if (sfio->pa[i] == NULL)
328 break;
329 KASSERT(vm_page_wired(sfio->pa[i]),
330 ("sfio %p page %d %p not wired", sfio, i, sfio->pa[i]));
331 if (i == 0)
332 continue;
333 KASSERT(sfio->pa[0]->object == sfio->pa[i]->object,
334 ("sfio %p page %d %p wrong owner %p %p", sfio, i,
335 sfio->pa[i], sfio->pa[0]->object, sfio->pa[i]->object));
336 KASSERT(sfio->pa[0]->pindex + i == sfio->pa[i]->pindex,
337 ("sfio %p page %d %p wrong index %jx %jx", sfio, i,
338 sfio->pa[i], (uintmax_t)sfio->pa[0]->pindex,
339 (uintmax_t)sfio->pa[i]->pindex));
340 }
341 #endif
342
343 vm_object_pip_wakeup(sfio->obj);
344
345 if (sfio->m == NULL) {
346 /*
347 * Either I/O operation failed, or we failed to allocate
348 * buffers, or we bailed out on first busy page, or we
349 * succeeded filling the request without any I/Os. Anyway,
350 * pru_send hadn't been executed - nothing had been sent
351 * to the socket yet.
352 */
353 MPASS((curthread->td_pflags & TDP_KTHREAD) == 0);
354 free(sfio, M_SENDFILE);
355 return;
356 }
357
358 #if defined(KERN_TLS) && defined(INVARIANTS)
359 if ((sfio->m->m_flags & M_EXTPG) != 0)
360 KASSERT(sfio->tls == sfio->m->m_epg_tls,
361 ("TLS session mismatch"));
362 else
363 KASSERT(sfio->tls == NULL,
364 ("non-ext_pgs mbuf with TLS session"));
365 #endif
366 so = sfio->so;
367 CURVNET_SET(so->so_vnet);
368 if (__predict_false(sfio->error)) {
369 /*
370 * I/O operation failed. The state of data in the socket
371 * is now inconsistent, and all what we can do is to tear
372 * it down. Protocol abort method would tear down protocol
373 * state, free all ready mbufs and detach not ready ones.
374 * We will free the mbufs corresponding to this I/O manually.
375 *
376 * The socket would be marked with EIO and made available
377 * for read, so that application receives EIO on next
378 * syscall and eventually closes the socket.
379 */
380 so->so_proto->pr_abort(so);
381 so->so_error = EIO;
382
383 mb_free_notready(sfio->m, sfio->npages);
384 #ifdef KERN_TLS
385 } else if (sfio->tls != NULL && sfio->tls->mode == TCP_TLS_MODE_SW) {
386 /*
387 * I/O operation is complete, but we still need to
388 * encrypt. We cannot do this in the interrupt thread
389 * of the disk controller, so forward the mbufs to a
390 * different thread.
391 *
392 * Donate the socket reference from sfio to rather
393 * than explicitly invoking soref().
394 */
395 ktls_enqueue(sfio->m, so, sfio->npages);
396 goto out_with_ref;
397 #endif
398 } else
399 (void)so->so_proto->pr_ready(so, sfio->m, sfio->npages);
400
401 sorele(so);
402 #ifdef KERN_TLS
403 out_with_ref:
404 #endif
405 CURVNET_RESTORE();
406 free(sfio, M_SENDFILE);
407 }
408
409 /*
410 * Iterate through pages vector and request paging for non-valid pages.
411 */
412 static int
413 sendfile_swapin(vm_object_t obj, struct sf_io *sfio, int *nios, off_t off,
414 off_t len, int rhpages, int flags)
415 {
416 vm_page_t *pa;
417 int a, count, count1, grabbed, i, j, npages, rv;
418
419 pa = sfio->pa;
420 npages = sfio->npages;
421 *nios = 0;
422 flags = (flags & SF_NODISKIO) ? VM_ALLOC_NOWAIT : 0;
423 sfio->pindex0 = OFF_TO_IDX(off);
424
425 /*
426 * First grab all the pages and wire them. Note that we grab
427 * only required pages. Readahead pages are dealt with later.
428 */
429 grabbed = vm_page_grab_pages_unlocked(obj, OFF_TO_IDX(off),
430 VM_ALLOC_NORMAL | VM_ALLOC_WIRED | flags, pa, npages);
431 if (grabbed < npages) {
432 for (int i = grabbed; i < npages; i++)
433 pa[i] = NULL;
434 npages = grabbed;
435 rhpages = 0;
436 }
437
438 for (i = 0; i < npages;) {
439 /* Skip valid pages. */
440 if (vm_page_is_valid(pa[i], vmoff(i, off) & PAGE_MASK,
441 xfsize(i, npages, off, len))) {
442 vm_page_xunbusy(pa[i]);
443 SFSTAT_INC(sf_pages_valid);
444 i++;
445 continue;
446 }
447
448 /*
449 * Next page is invalid. Check if it belongs to pager. It
450 * may not be there, which is a regular situation for shmem
451 * pager. For vnode pager this happens only in case of
452 * a sparse file.
453 *
454 * Important feature of vm_pager_has_page() is the hint
455 * stored in 'a', about how many pages we can pagein after
456 * this page in a single I/O.
457 */
458 VM_OBJECT_RLOCK(obj);
459 if (!vm_pager_has_page(obj, OFF_TO_IDX(vmoff(i, off)), NULL,
460 &a)) {
461 VM_OBJECT_RUNLOCK(obj);
462 pmap_zero_page(pa[i]);
463 vm_page_valid(pa[i]);
464 MPASS(pa[i]->dirty == 0);
465 vm_page_xunbusy(pa[i]);
466 i++;
467 continue;
468 }
469 VM_OBJECT_RUNLOCK(obj);
470
471 /*
472 * We want to pagein as many pages as possible, limited only
473 * by the 'a' hint and actual request.
474 */
475 count = min(a + 1, npages - i);
476
477 /*
478 * We should not pagein into a valid page because
479 * there might be still unfinished write tracked by
480 * e.g. a buffer, thus we substitute any valid pages
481 * with the bogus one.
482 *
483 * We must not leave around xbusy pages which are not
484 * part of the run passed to vm_pager_getpages(),
485 * otherwise pager might deadlock waiting for the busy
486 * status of the page, e.g. if it constitues the
487 * buffer needed to validate other page.
488 *
489 * First trim the end of the run consisting of the
490 * valid pages, then replace the rest of the valid
491 * with bogus.
492 */
493 count1 = count;
494 for (j = i + count - 1; j > i; j--) {
495 if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK,
496 xfsize(j, npages, off, len))) {
497 vm_page_xunbusy(pa[j]);
498 SFSTAT_INC(sf_pages_valid);
499 count--;
500 } else {
501 break;
502 }
503 }
504
505 /*
506 * The last page in the run pa[i + count - 1] is
507 * guaranteed to be invalid by the trim above, so it
508 * is not replaced with bogus, thus -1 in the loop end
509 * condition.
510 */
511 MPASS(pa[i + count - 1]->valid != VM_PAGE_BITS_ALL);
512 for (j = i + 1; j < i + count - 1; j++) {
513 if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK,
514 xfsize(j, npages, off, len))) {
515 vm_page_xunbusy(pa[j]);
516 SFSTAT_INC(sf_pages_valid);
517 SFSTAT_INC(sf_pages_bogus);
518 pa[j] = bogus_page;
519 }
520 }
521
522 refcount_acquire(&sfio->nios);
523 rv = vm_pager_get_pages_async(obj, pa + i, count, NULL,
524 i + count == npages ? &rhpages : NULL,
525 &sendfile_iodone, sfio);
526 if (__predict_false(rv != VM_PAGER_OK)) {
527 sendfile_iowait(sfio, "sferrio");
528
529 /*
530 * Do remaining pages recovery before returning EIO.
531 * Pages from 0 to npages are wired.
532 * Pages from (i + count1) to npages are busied.
533 */
534 for (j = 0; j < npages; j++) {
535 if (j >= i + count1)
536 vm_page_xunbusy(pa[j]);
537 KASSERT(pa[j] != NULL && pa[j] != bogus_page,
538 ("%s: page %p[%d] I/O recovery failure",
539 __func__, pa, j));
540 vm_page_unwire(pa[j], PQ_INACTIVE);
541 pa[j] = NULL;
542 }
543 return (EIO);
544 }
545
546 SFSTAT_INC(sf_iocnt);
547 SFSTAT_ADD(sf_pages_read, count);
548 if (i + count == npages)
549 SFSTAT_ADD(sf_rhpages_read, rhpages);
550
551 i += count1;
552 (*nios)++;
553 }
554
555 if (*nios == 0 && npages != 0)
556 SFSTAT_INC(sf_noiocnt);
557
558 return (0);
559 }
560
561 static int
562 sendfile_getobj(struct thread *td, struct file *fp, vm_object_t *obj_res,
563 struct vnode **vp_res, struct shmfd **shmfd_res, off_t *obj_size,
564 int *bsize)
565 {
566 vm_object_t obj;
567 struct vnode *vp;
568 struct shmfd *shmfd;
569 int error;
570
571 error = 0;
572 vp = *vp_res = NULL;
573 obj = NULL;
574 shmfd = *shmfd_res = NULL;
575 *bsize = 0;
576
577 /*
578 * The file descriptor must be a regular file and have a
579 * backing VM object.
580 */
581 if (fp->f_type == DTYPE_VNODE) {
582 vp = fp->f_vnode;
583 vn_lock(vp, LK_SHARED | LK_RETRY);
584 if (vp->v_type != VREG) {
585 error = EINVAL;
586 goto out;
587 }
588 *bsize = vp->v_mount->mnt_stat.f_iosize;
589 obj = vp->v_object;
590 if (obj == NULL) {
591 error = EINVAL;
592 goto out;
593 }
594
595 /*
596 * Use the pager size when available to simplify synchronization
597 * with filesystems, which otherwise must atomically update both
598 * the vnode pager size and file size.
599 */
600 if (obj->type == OBJT_VNODE) {
601 VM_OBJECT_RLOCK(obj);
602 *obj_size = obj->un_pager.vnp.vnp_size;
603 } else {
604 error = vn_getsize_locked(vp, obj_size, td->td_ucred);
605 if (error != 0)
606 goto out;
607 VM_OBJECT_RLOCK(obj);
608 }
609 } else if (fp->f_type == DTYPE_SHM) {
610 shmfd = fp->f_data;
611 obj = shmfd->shm_object;
612 VM_OBJECT_RLOCK(obj);
613 *obj_size = shmfd->shm_size;
614 } else {
615 error = EINVAL;
616 goto out;
617 }
618
619 if ((obj->flags & OBJ_DEAD) != 0) {
620 VM_OBJECT_RUNLOCK(obj);
621 error = EBADF;
622 goto out;
623 }
624
625 /*
626 * Temporarily increase the backing VM object's reference
627 * count so that a forced reclamation of its vnode does not
628 * immediately destroy it.
629 */
630 vm_object_reference_locked(obj);
631 VM_OBJECT_RUNLOCK(obj);
632 *obj_res = obj;
633 *vp_res = vp;
634 *shmfd_res = shmfd;
635
636 out:
637 if (vp != NULL)
638 VOP_UNLOCK(vp);
639 return (error);
640 }
641
642 static int
643 sendfile_getsock(struct thread *td, int s, struct file **sock_fp,
644 struct socket **so)
645 {
646 int error;
647
648 *sock_fp = NULL;
649 *so = NULL;
650
651 /*
652 * The socket must be a stream socket and connected.
653 */
654 error = getsock(td, s, &cap_send_rights, sock_fp);
655 if (error != 0)
656 return (error);
657 *so = (*sock_fp)->f_data;
658 if ((*so)->so_type != SOCK_STREAM)
659 return (EINVAL);
660 /*
661 * SCTP one-to-one style sockets currently don't work with
662 * sendfile(). So indicate EINVAL for now.
663 */
664 if ((*so)->so_proto->pr_protocol == IPPROTO_SCTP)
665 return (EINVAL);
666 return (0);
667 }
668
669 int
670 vn_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio,
671 struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags,
672 struct thread *td)
673 {
674 struct file *sock_fp;
675 struct vnode *vp;
676 struct vm_object *obj;
677 vm_page_t pga;
678 struct socket *so;
679 #ifdef KERN_TLS
680 struct ktls_session *tls;
681 #endif
682 struct mbuf *m, *mh, *mhtail;
683 struct sf_buf *sf;
684 struct shmfd *shmfd;
685 struct sendfile_sync *sfs;
686 struct vattr va;
687 off_t off, sbytes, rem, obj_size, nobj_size;
688 int bsize, error, ext_pgs_idx, hdrlen, max_pgs, softerr;
689 #ifdef KERN_TLS
690 int tls_enq_cnt;
691 #endif
692 bool use_ext_pgs;
693
694 obj = NULL;
695 so = NULL;
696 m = mh = NULL;
697 sfs = NULL;
698 #ifdef KERN_TLS
699 tls = NULL;
700 #endif
701 hdrlen = sbytes = 0;
702 softerr = 0;
703 use_ext_pgs = false;
704
705 error = sendfile_getobj(td, fp, &obj, &vp, &shmfd, &obj_size, &bsize);
706 if (error != 0)
707 return (error);
708
709 error = sendfile_getsock(td, sockfd, &sock_fp, &so);
710 if (error != 0)
711 goto out;
712
713 #ifdef MAC
714 error = mac_socket_check_send(td->td_ucred, so);
715 if (error != 0)
716 goto out;
717 #endif
718
719 SFSTAT_INC(sf_syscalls);
720 SFSTAT_ADD(sf_rhpages_requested, SF_READAHEAD(flags));
721
722 if (flags & SF_SYNC) {
723 sfs = malloc(sizeof(*sfs), M_SENDFILE, M_WAITOK | M_ZERO);
724 mtx_init(&sfs->mtx, "sendfile", NULL, MTX_DEF);
725 cv_init(&sfs->cv, "sendfile");
726 sfs->waiting = true;
727 }
728
729 rem = nbytes ? omin(nbytes, obj_size - offset) : obj_size - offset;
730
731 /*
732 * Protect against multiple writers to the socket.
733 *
734 * XXXRW: Historically this has assumed non-interruptibility, so now
735 * we implement that, but possibly shouldn't.
736 */
737 error = SOCK_IO_SEND_LOCK(so, SBL_WAIT | SBL_NOINTR);
738 if (error != 0)
739 goto out;
740 #ifdef KERN_TLS
741 tls = ktls_hold(so->so_snd.sb_tls_info);
742 #endif
743
744 /*
745 * Loop through the pages of the file, starting with the requested
746 * offset. Get a file page (do I/O if necessary), map the file page
747 * into an sf_buf, attach an mbuf header to the sf_buf, and queue
748 * it on the socket.
749 * This is done in two loops. The inner loop turns as many pages
750 * as it can, up to available socket buffer space, without blocking
751 * into mbufs to have it bulk delivered into the socket send buffer.
752 * The outer loop checks the state and available space of the socket
753 * and takes care of the overall progress.
754 */
755 for (off = offset; rem > 0; ) {
756 struct sf_io *sfio;
757 vm_page_t *pa;
758 struct mbuf *m0, *mtail;
759 int nios, space, npages, rhpages;
760
761 mtail = NULL;
762 /*
763 * Check the socket state for ongoing connection,
764 * no errors and space in socket buffer.
765 * If space is low allow for the remainder of the
766 * file to be processed if it fits the socket buffer.
767 * Otherwise block in waiting for sufficient space
768 * to proceed, or if the socket is nonblocking, return
769 * to userland with EAGAIN while reporting how far
770 * we've come.
771 * We wait until the socket buffer has significant free
772 * space to do bulk sends. This makes good use of file
773 * system read ahead and allows packet segmentation
774 * offloading hardware to take over lots of work. If
775 * we were not careful here we would send off only one
776 * sfbuf at a time.
777 */
778 SOCKBUF_LOCK(&so->so_snd);
779 if (so->so_snd.sb_lowat < so->so_snd.sb_hiwat / 2)
780 so->so_snd.sb_lowat = so->so_snd.sb_hiwat / 2;
781 retry_space:
782 if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
783 error = EPIPE;
784 SOCKBUF_UNLOCK(&so->so_snd);
785 goto done;
786 } else if (so->so_error) {
787 error = so->so_error;
788 so->so_error = 0;
789 SOCKBUF_UNLOCK(&so->so_snd);
790 goto done;
791 }
792 if ((so->so_state & SS_ISCONNECTED) == 0) {
793 SOCKBUF_UNLOCK(&so->so_snd);
794 error = ENOTCONN;
795 goto done;
796 }
797
798 space = sbspace(&so->so_snd);
799 if (space < rem &&
800 (space <= 0 ||
801 space < so->so_snd.sb_lowat)) {
802 if (so->so_state & SS_NBIO) {
803 SOCKBUF_UNLOCK(&so->so_snd);
804 error = EAGAIN;
805 goto done;
806 }
807 /*
808 * sbwait drops the lock while sleeping.
809 * When we loop back to retry_space the
810 * state may have changed and we retest
811 * for it.
812 */
813 error = sbwait(so, SO_SND);
814 /*
815 * An error from sbwait usually indicates that we've
816 * been interrupted by a signal. If we've sent anything
817 * then return bytes sent, otherwise return the error.
818 */
819 if (error != 0) {
820 SOCKBUF_UNLOCK(&so->so_snd);
821 goto done;
822 }
823 goto retry_space;
824 }
825 SOCKBUF_UNLOCK(&so->so_snd);
826
827 /*
828 * At the beginning of the first loop check if any headers
829 * are specified and copy them into mbufs. Reduce space in
830 * the socket buffer by the size of the header mbuf chain.
831 * Clear hdr_uio here and hdrlen at the end of the first loop.
832 */
833 if (hdr_uio != NULL && hdr_uio->uio_resid > 0) {
834 hdr_uio->uio_td = td;
835 hdr_uio->uio_rw = UIO_WRITE;
836 #ifdef KERN_TLS
837 if (tls != NULL)
838 mh = m_uiotombuf(hdr_uio, M_WAITOK, space,
839 tls->params.max_frame_len, M_EXTPG);
840 else
841 #endif
842 mh = m_uiotombuf(hdr_uio, M_WAITOK,
843 space, 0, 0);
844 hdrlen = m_length(mh, &mhtail);
845 space -= hdrlen;
846 /*
847 * If header consumed all the socket buffer space,
848 * don't waste CPU cycles and jump to the end.
849 */
850 if (space == 0) {
851 sfio = NULL;
852 nios = 0;
853 goto prepend_header;
854 }
855 hdr_uio = NULL;
856 }
857
858 if (vp != NULL) {
859 error = vn_lock(vp, LK_SHARED);
860 if (error != 0)
861 goto done;
862
863 /*
864 * Check to see if the file size has changed.
865 */
866 if (obj->type == OBJT_VNODE) {
867 VM_OBJECT_RLOCK(obj);
868 nobj_size = obj->un_pager.vnp.vnp_size;
869 VM_OBJECT_RUNLOCK(obj);
870 } else {
871 error = VOP_GETATTR(vp, &va, td->td_ucred);
872 if (error != 0) {
873 VOP_UNLOCK(vp);
874 goto done;
875 }
876 nobj_size = va.va_size;
877 }
878 if (off >= nobj_size) {
879 VOP_UNLOCK(vp);
880 goto done;
881 }
882 if (nobj_size != obj_size) {
883 obj_size = nobj_size;
884 rem = nbytes ? omin(nbytes + offset, obj_size) :
885 obj_size;
886 rem -= off;
887 }
888 }
889
890 if (space > rem)
891 space = rem;
892 else if (space > PAGE_SIZE) {
893 /*
894 * Use page boundaries when possible for large
895 * requests.
896 */
897 if (off & PAGE_MASK)
898 space -= (PAGE_SIZE - (off & PAGE_MASK));
899 space = trunc_page(space);
900 if (off & PAGE_MASK)
901 space += (PAGE_SIZE - (off & PAGE_MASK));
902 }
903
904 npages = howmany(space + (off & PAGE_MASK), PAGE_SIZE);
905
906 /*
907 * Calculate maximum allowed number of pages for readahead
908 * at this iteration. If SF_USER_READAHEAD was set, we don't
909 * do any heuristics and use exactly the value supplied by
910 * application. Otherwise, we allow readahead up to "rem".
911 * If application wants more, let it be, but there is no
912 * reason to go above maxphys. Also check against "obj_size",
913 * since vm_pager_has_page() can hint beyond EOF.
914 */
915 if (flags & SF_USER_READAHEAD) {
916 rhpages = SF_READAHEAD(flags);
917 } else {
918 rhpages = howmany(rem + (off & PAGE_MASK), PAGE_SIZE) -
919 npages;
920 rhpages += SF_READAHEAD(flags);
921 }
922 rhpages = min(howmany(maxphys, PAGE_SIZE), rhpages);
923 rhpages = min(howmany(obj_size - trunc_page(off), PAGE_SIZE) -
924 npages, rhpages);
925
926 sfio = malloc(sizeof(struct sf_io) +
927 npages * sizeof(vm_page_t), M_SENDFILE, M_WAITOK);
928 refcount_init(&sfio->nios, 1);
929 sfio->obj = obj;
930 sfio->error = 0;
931 sfio->m = NULL;
932 sfio->npages = npages;
933 #ifdef KERN_TLS
934 /*
935 * This doesn't use ktls_hold() because sfio->m will
936 * also have a reference on 'tls' that will be valid
937 * for all of sfio's lifetime.
938 */
939 sfio->tls = tls;
940 #endif
941 vm_object_pip_add(obj, 1);
942 error = sendfile_swapin(obj, sfio, &nios, off, space, rhpages,
943 flags);
944 if (error != 0) {
945 if (vp != NULL)
946 VOP_UNLOCK(vp);
947 sendfile_iodone(sfio, NULL, 0, error);
948 goto done;
949 }
950
951 /*
952 * Loop and construct maximum sized mbuf chain to be bulk
953 * dumped into socket buffer.
954 */
955 pa = sfio->pa;
956
957 /*
958 * Use unmapped mbufs if enabled for TCP. Unmapped
959 * bufs are restricted to TCP as that is what has been
960 * tested. In particular, unmapped mbufs have not
961 * been tested with UNIX-domain sockets.
962 *
963 * TLS frames always require unmapped mbufs.
964 */
965 if ((mb_use_ext_pgs &&
966 so->so_proto->pr_protocol == IPPROTO_TCP)
967 #ifdef KERN_TLS
968 || tls != NULL
969 #endif
970 ) {
971 use_ext_pgs = true;
972 #ifdef KERN_TLS
973 if (tls != NULL)
974 max_pgs = num_pages(tls->params.max_frame_len);
975 else
976 #endif
977 max_pgs = MBUF_PEXT_MAX_PGS;
978
979 /* Start at last index, to wrap on first use. */
980 ext_pgs_idx = max_pgs - 1;
981 }
982
983 for (int i = 0; i < npages; i++) {
984 /*
985 * If a page wasn't grabbed successfully, then
986 * trim the array. Can happen only with SF_NODISKIO.
987 */
988 if (pa[i] == NULL) {
989 SFSTAT_INC(sf_busy);
990 fixspace(npages, i, off, &space);
991 sfio->npages = i;
992 softerr = EBUSY;
993 break;
994 }
995 pga = pa[i];
996 if (pga == bogus_page)
997 pga = vm_page_relookup(obj, sfio->pindex0 + i);
998
999 if (use_ext_pgs) {
1000 off_t xfs;
1001
1002 ext_pgs_idx++;
1003 if (ext_pgs_idx == max_pgs) {
1004 m0 = mb_alloc_ext_pgs(M_WAITOK,
1005 sendfile_free_mext_pg);
1006
1007 if (flags & SF_NOCACHE) {
1008 m0->m_ext.ext_flags |=
1009 EXT_FLAG_NOCACHE;
1010
1011 /*
1012 * See comment below regarding
1013 * ignoring SF_NOCACHE for the
1014 * last page.
1015 */
1016 if ((npages - i <= max_pgs) &&
1017 ((off + space) & PAGE_MASK) &&
1018 (rem > space || rhpages > 0))
1019 m0->m_ext.ext_flags |=
1020 EXT_FLAG_CACHE_LAST;
1021 }
1022 if (sfs != NULL) {
1023 m0->m_ext.ext_flags |=
1024 EXT_FLAG_SYNC;
1025 m0->m_ext.ext_arg1 = sfs;
1026 mtx_lock(&sfs->mtx);
1027 sfs->count++;
1028 mtx_unlock(&sfs->mtx);
1029 }
1030 ext_pgs_idx = 0;
1031
1032 /* Append to mbuf chain. */
1033 if (mtail != NULL)
1034 mtail->m_next = m0;
1035 else
1036 m = m0;
1037 mtail = m0;
1038 m0->m_epg_1st_off =
1039 vmoff(i, off) & PAGE_MASK;
1040 }
1041 if (nios) {
1042 mtail->m_flags |= M_NOTREADY;
1043 m0->m_epg_nrdy++;
1044 }
1045
1046 m0->m_epg_pa[ext_pgs_idx] = VM_PAGE_TO_PHYS(pga);
1047 m0->m_epg_npgs++;
1048 xfs = xfsize(i, npages, off, space);
1049 m0->m_epg_last_len = xfs;
1050 MBUF_EXT_PGS_ASSERT_SANITY(m0);
1051 mtail->m_len += xfs;
1052 mtail->m_ext.ext_size += PAGE_SIZE;
1053 continue;
1054 }
1055
1056 /*
1057 * Get a sendfile buf. When allocating the
1058 * first buffer for mbuf chain, we usually
1059 * wait as long as necessary, but this wait
1060 * can be interrupted. For consequent
1061 * buffers, do not sleep, since several
1062 * threads might exhaust the buffers and then
1063 * deadlock.
1064 */
1065 sf = sf_buf_alloc(pga,
1066 m != NULL ? SFB_NOWAIT : SFB_CATCH);
1067 if (sf == NULL) {
1068 SFSTAT_INC(sf_allocfail);
1069 sendfile_iowait(sfio, "sfnosf");
1070 for (int j = i; j < npages; j++) {
1071 vm_page_unwire(pa[j], PQ_INACTIVE);
1072 pa[j] = NULL;
1073 }
1074 if (m == NULL)
1075 softerr = ENOBUFS;
1076 fixspace(npages, i, off, &space);
1077 sfio->npages = i;
1078 break;
1079 }
1080
1081 m0 = m_get(M_WAITOK, MT_DATA);
1082 m0->m_ext.ext_buf = (char *)sf_buf_kva(sf);
1083 m0->m_ext.ext_size = PAGE_SIZE;
1084 m0->m_ext.ext_arg1 = sf;
1085 m0->m_ext.ext_type = EXT_SFBUF;
1086 m0->m_ext.ext_flags = EXT_FLAG_EMBREF;
1087 m0->m_ext.ext_free = sendfile_free_mext;
1088 /*
1089 * SF_NOCACHE sets the page as being freed upon send.
1090 * However, we ignore it for the last page in 'space',
1091 * if the page is truncated, and we got more data to
1092 * send (rem > space), or if we have readahead
1093 * configured (rhpages > 0).
1094 */
1095 if ((flags & SF_NOCACHE) &&
1096 (i != npages - 1 ||
1097 !((off + space) & PAGE_MASK) ||
1098 !(rem > space || rhpages > 0)))
1099 m0->m_ext.ext_flags |= EXT_FLAG_NOCACHE;
1100 if (sfs != NULL) {
1101 m0->m_ext.ext_flags |= EXT_FLAG_SYNC;
1102 m0->m_ext.ext_arg2 = sfs;
1103 mtx_lock(&sfs->mtx);
1104 sfs->count++;
1105 mtx_unlock(&sfs->mtx);
1106 }
1107 m0->m_ext.ext_count = 1;
1108 m0->m_flags |= (M_EXT | M_RDONLY);
1109 if (nios)
1110 m0->m_flags |= M_NOTREADY;
1111 m0->m_data = (char *)sf_buf_kva(sf) +
1112 (vmoff(i, off) & PAGE_MASK);
1113 m0->m_len = xfsize(i, npages, off, space);
1114
1115 /* Append to mbuf chain. */
1116 if (mtail != NULL)
1117 mtail->m_next = m0;
1118 else
1119 m = m0;
1120 mtail = m0;
1121 }
1122
1123 if (vp != NULL)
1124 VOP_UNLOCK(vp);
1125
1126 /* Keep track of bytes processed. */
1127 off += space;
1128 rem -= space;
1129
1130 /*
1131 * Prepend header, if any. Save pointer to first mbuf
1132 * with a page.
1133 */
1134 if (hdrlen) {
1135 prepend_header:
1136 m0 = mhtail->m_next = m;
1137 m = mh;
1138 mh = NULL;
1139 } else
1140 m0 = m;
1141
1142 if (m == NULL) {
1143 KASSERT(softerr, ("%s: m NULL, no error", __func__));
1144 error = softerr;
1145 sendfile_iodone(sfio, NULL, 0, 0);
1146 goto done;
1147 }
1148
1149 /* Add the buffer chain to the socket buffer. */
1150 KASSERT(m_length(m, NULL) == space + hdrlen,
1151 ("%s: mlen %u space %d hdrlen %d",
1152 __func__, m_length(m, NULL), space, hdrlen));
1153
1154 CURVNET_SET(so->so_vnet);
1155 #ifdef KERN_TLS
1156 if (tls != NULL)
1157 ktls_frame(m, tls, &tls_enq_cnt, TLS_RLTYPE_APP);
1158 #endif
1159 if (nios == 0) {
1160 /*
1161 * If sendfile_swapin() didn't initiate any I/Os,
1162 * which happens if all data is cached in VM, or if
1163 * the header consumed all socket buffer space and
1164 * sfio is NULL, then we can send data right now
1165 * without the PRUS_NOTREADY flag.
1166 */
1167 if (sfio != NULL)
1168 sendfile_iodone(sfio, NULL, 0, 0);
1169 #ifdef KERN_TLS
1170 if (tls != NULL && tls->mode == TCP_TLS_MODE_SW) {
1171 error = so->so_proto->pr_send(so,
1172 PRUS_NOTREADY, m, NULL, NULL, td);
1173 if (error != 0) {
1174 m_freem(m);
1175 } else {
1176 soref(so);
1177 ktls_enqueue(m, so, tls_enq_cnt);
1178 }
1179 } else
1180 #endif
1181 error = so->so_proto->pr_send(so, 0, m, NULL,
1182 NULL, td);
1183 } else {
1184 sfio->so = so;
1185 sfio->m = m0;
1186 soref(so);
1187 error = so->so_proto->pr_send(so, PRUS_NOTREADY, m,
1188 NULL, NULL, td);
1189 sendfile_iodone(sfio, NULL, 0, error);
1190 }
1191 CURVNET_RESTORE();
1192
1193 m = NULL;
1194 if (error)
1195 goto done;
1196 sbytes += space + hdrlen;
1197 if (hdrlen)
1198 hdrlen = 0;
1199 if (softerr) {
1200 error = softerr;
1201 goto done;
1202 }
1203 }
1204
1205 /*
1206 * Send trailers. Wimp out and use writev(2).
1207 */
1208 if (trl_uio != NULL) {
1209 SOCK_IO_SEND_UNLOCK(so);
1210 error = kern_writev(td, sockfd, trl_uio);
1211 if (error == 0)
1212 sbytes += td->td_retval[0];
1213 goto out;
1214 }
1215
1216 done:
1217 SOCK_IO_SEND_UNLOCK(so);
1218 out:
1219 /*
1220 * If there was no error we have to clear td->td_retval[0]
1221 * because it may have been set by writev.
1222 */
1223 if (error == 0) {
1224 td->td_retval[0] = 0;
1225 }
1226 if (sent != NULL) {
1227 (*sent) = sbytes;
1228 }
1229 if (obj != NULL)
1230 vm_object_deallocate(obj);
1231 if (so)
1232 fdrop(sock_fp, td);
1233 if (m)
1234 m_freem(m);
1235 if (mh)
1236 m_freem(mh);
1237
1238 if (sfs != NULL) {
1239 mtx_lock(&sfs->mtx);
1240 if (sfs->count != 0)
1241 error = cv_wait_sig(&sfs->cv, &sfs->mtx);
1242 if (sfs->count == 0) {
1243 sendfile_sync_destroy(sfs);
1244 } else {
1245 sfs->waiting = false;
1246 mtx_unlock(&sfs->mtx);
1247 }
1248 }
1249 #ifdef KERN_TLS
1250 if (tls != NULL)
1251 ktls_free(tls);
1252 #endif
1253
1254 if (error == ERESTART)
1255 error = EINTR;
1256
1257 return (error);
1258 }
1259
1260 static int
1261 sendfile(struct thread *td, struct sendfile_args *uap, int compat)
1262 {
1263 struct sf_hdtr hdtr;
1264 struct uio *hdr_uio, *trl_uio;
1265 struct file *fp;
1266 off_t sbytes;
1267 int error;
1268
1269 /*
1270 * File offset must be positive. If it goes beyond EOF
1271 * we send only the header/trailer and no payload data.
1272 */
1273 if (uap->offset < 0)
1274 return (EINVAL);
1275
1276 sbytes = 0;
1277 hdr_uio = trl_uio = NULL;
1278
1279 if (uap->hdtr != NULL) {
1280 error = copyin(uap->hdtr, &hdtr, sizeof(hdtr));
1281 if (error != 0)
1282 goto out;
1283 if (hdtr.headers != NULL) {
1284 error = copyinuio(hdtr.headers, hdtr.hdr_cnt,
1285 &hdr_uio);
1286 if (error != 0)
1287 goto out;
1288 #ifdef COMPAT_FREEBSD4
1289 /*
1290 * In FreeBSD < 5.0 the nbytes to send also included
1291 * the header. If compat is specified subtract the
1292 * header size from nbytes.
1293 */
1294 if (compat) {
1295 if (uap->nbytes > hdr_uio->uio_resid)
1296 uap->nbytes -= hdr_uio->uio_resid;
1297 else
1298 uap->nbytes = 0;
1299 }
1300 #endif
1301 }
1302 if (hdtr.trailers != NULL) {
1303 error = copyinuio(hdtr.trailers, hdtr.trl_cnt,
1304 &trl_uio);
1305 if (error != 0)
1306 goto out;
1307 }
1308 }
1309
1310 AUDIT_ARG_FD(uap->fd);
1311
1312 /*
1313 * sendfile(2) can start at any offset within a file so we require
1314 * CAP_READ+CAP_SEEK = CAP_PREAD.
1315 */
1316 if ((error = fget_read(td, uap->fd, &cap_pread_rights, &fp)) != 0)
1317 goto out;
1318
1319 error = fo_sendfile(fp, uap->s, hdr_uio, trl_uio, uap->offset,
1320 uap->nbytes, &sbytes, uap->flags, td);
1321 fdrop(fp, td);
1322
1323 if (uap->sbytes != NULL)
1324 copyout(&sbytes, uap->sbytes, sizeof(off_t));
1325
1326 out:
1327 free(hdr_uio, M_IOV);
1328 free(trl_uio, M_IOV);
1329 return (error);
1330 }
1331
1332 /*
1333 * sendfile(2)
1334 *
1335 * int sendfile(int fd, int s, off_t offset, size_t nbytes,
1336 * struct sf_hdtr *hdtr, off_t *sbytes, int flags)
1337 *
1338 * Send a file specified by 'fd' and starting at 'offset' to a socket
1339 * specified by 's'. Send only 'nbytes' of the file or until EOF if nbytes ==
1340 * 0. Optionally add a header and/or trailer to the socket output. If
1341 * specified, write the total number of bytes sent into *sbytes.
1342 */
1343 int
1344 sys_sendfile(struct thread *td, struct sendfile_args *uap)
1345 {
1346
1347 return (sendfile(td, uap, 0));
1348 }
1349
1350 #ifdef COMPAT_FREEBSD4
1351 int
1352 freebsd4_sendfile(struct thread *td, struct freebsd4_sendfile_args *uap)
1353 {
1354 struct sendfile_args args;
1355
1356 args.fd = uap->fd;
1357 args.s = uap->s;
1358 args.offset = uap->offset;
1359 args.nbytes = uap->nbytes;
1360 args.hdtr = uap->hdtr;
1361 args.sbytes = uap->sbytes;
1362 args.flags = uap->flags;
1363
1364 return (sendfile(td, &args, 1));
1365 }
1366 #endif /* COMPAT_FREEBSD4 */
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