1 /*-
2 * Copyright (c) 2013-2015 Gleb Smirnoff <[email protected]>
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 <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
sfstat_init(const void * unused)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
sfstat_sysctl(SYSCTL_HANDLER_ARGS)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 static void
sendfile_free_mext(struct mbuf * m)123 sendfile_free_mext(struct mbuf *m)
124 {
125 struct sf_buf *sf;
126 vm_page_t pg;
127 int flags;
128
129 KASSERT(m->m_flags & M_EXT && m->m_ext.ext_type == EXT_SFBUF,
130 ("%s: m %p !M_EXT or !EXT_SFBUF", __func__, m));
131
132 sf = m->m_ext.ext_arg1;
133 pg = sf_buf_page(sf);
134 flags = (m->m_ext.ext_flags & EXT_FLAG_NOCACHE) != 0 ? VPR_TRYFREE : 0;
135
136 sf_buf_free(sf);
137 vm_page_release(pg, flags);
138
139 if (m->m_ext.ext_flags & EXT_FLAG_SYNC) {
140 struct sendfile_sync *sfs = m->m_ext.ext_arg2;
141
142 mtx_lock(&sfs->mtx);
143 KASSERT(sfs->count > 0, ("Sendfile sync botchup count == 0"));
144 if (--sfs->count == 0)
145 cv_signal(&sfs->cv);
146 mtx_unlock(&sfs->mtx);
147 }
148 }
149
150 /*
151 * Helper function to calculate how much data to put into page i of n.
152 * Only first and last pages are special.
153 */
154 static inline off_t
xfsize(int i,int n,off_t off,off_t len)155 xfsize(int i, int n, off_t off, off_t len)
156 {
157
158 if (i == 0)
159 return (omin(PAGE_SIZE - (off & PAGE_MASK), len));
160
161 if (i == n - 1 && ((off + len) & PAGE_MASK) > 0)
162 return ((off + len) & PAGE_MASK);
163
164 return (PAGE_SIZE);
165 }
166
167 /*
168 * Helper function to get offset within object for i page.
169 */
170 static inline vm_ooffset_t
vmoff(int i,off_t off)171 vmoff(int i, off_t off)
172 {
173
174 if (i == 0)
175 return ((vm_ooffset_t)off);
176
177 return (trunc_page(off + i * PAGE_SIZE));
178 }
179
180 /*
181 * Helper function used when allocation of a page or sf_buf failed.
182 * Pretend as if we don't have enough space, subtract xfsize() of
183 * all pages that failed.
184 */
185 static inline void
fixspace(int old,int new,off_t off,int * space)186 fixspace(int old, int new, off_t off, int *space)
187 {
188
189 KASSERT(old > new, ("%s: old %d new %d", __func__, old, new));
190
191 /* Subtract last one. */
192 *space -= xfsize(old - 1, old, off, *space);
193 old--;
194
195 if (new == old)
196 /* There was only one page. */
197 return;
198
199 /* Subtract first one. */
200 if (new == 0) {
201 *space -= xfsize(0, old, off, *space);
202 new++;
203 }
204
205 /* Rest of pages are full sized. */
206 *space -= (old - new) * PAGE_SIZE;
207
208 KASSERT(*space >= 0, ("%s: space went backwards", __func__));
209 }
210
211 /*
212 * I/O completion callback.
213 */
214 static void
sendfile_iodone(void * arg,vm_page_t * pg,int count,int error)215 sendfile_iodone(void *arg, vm_page_t *pg, int count, int error)
216 {
217 struct sf_io *sfio = arg;
218 struct socket *so = sfio->so;
219
220 for (int i = 0; i < count; i++)
221 if (pg[i] != bogus_page)
222 vm_page_xunbusy(pg[i]);
223
224 if (error)
225 sfio->error = error;
226
227 if (!refcount_release(&sfio->nios))
228 return;
229
230 CURVNET_SET(so->so_vnet);
231 if (sfio->error) {
232 struct mbuf *m;
233
234 /*
235 * I/O operation failed. The state of data in the socket
236 * is now inconsistent, and all what we can do is to tear
237 * it down. Protocol abort method would tear down protocol
238 * state, free all ready mbufs and detach not ready ones.
239 * We will free the mbufs corresponding to this I/O manually.
240 *
241 * The socket would be marked with EIO and made available
242 * for read, so that application receives EIO on next
243 * syscall and eventually closes the socket.
244 */
245 so->so_proto->pr_usrreqs->pru_abort(so);
246 so->so_error = EIO;
247
248 m = sfio->m;
249 for (int i = 0; i < sfio->npages; i++)
250 m = m_free(m);
251 } else
252 (void )(so->so_proto->pr_usrreqs->pru_ready)(so, sfio->m,
253 sfio->npages);
254
255 SOCK_LOCK(so);
256 sorele(so);
257 CURVNET_RESTORE();
258 free(sfio, M_TEMP);
259 }
260
261 /*
262 * Iterate through pages vector and request paging for non-valid pages.
263 */
264 static int
sendfile_swapin(vm_object_t obj,struct sf_io * sfio,int * nios,off_t off,off_t len,int npages,int rhpages,int flags)265 sendfile_swapin(vm_object_t obj, struct sf_io *sfio, int *nios, off_t off,
266 off_t len, int npages, int rhpages, int flags)
267 {
268 vm_page_t *pa = sfio->pa;
269 int grabbed;
270
271 *nios = 0;
272 flags = (flags & SF_NODISKIO) ? VM_ALLOC_NOWAIT : 0;
273
274 /*
275 * First grab all the pages and wire them. Note that we grab
276 * only required pages. Readahead pages are dealt with later.
277 */
278 VM_OBJECT_WLOCK(obj);
279
280 grabbed = vm_page_grab_pages(obj, OFF_TO_IDX(off),
281 VM_ALLOC_NORMAL | VM_ALLOC_WIRED | flags, pa, npages);
282 if (grabbed < npages) {
283 for (int i = grabbed; i < npages; i++)
284 pa[i] = NULL;
285 npages = grabbed;
286 rhpages = 0;
287 }
288
289 for (int i = 0; i < npages;) {
290 int j, a, count, rv;
291
292 /* Skip valid pages. */
293 if (vm_page_is_valid(pa[i], vmoff(i, off) & PAGE_MASK,
294 xfsize(i, npages, off, len))) {
295 vm_page_xunbusy(pa[i]);
296 SFSTAT_INC(sf_pages_valid);
297 i++;
298 continue;
299 }
300
301 /*
302 * Next page is invalid. Check if it belongs to pager. It
303 * may not be there, which is a regular situation for shmem
304 * pager. For vnode pager this happens only in case of
305 * a sparse file.
306 *
307 * Important feature of vm_pager_has_page() is the hint
308 * stored in 'a', about how many pages we can pagein after
309 * this page in a single I/O.
310 */
311 if (!vm_pager_has_page(obj, OFF_TO_IDX(vmoff(i, off)), NULL,
312 &a)) {
313 pmap_zero_page(pa[i]);
314 pa[i]->valid = VM_PAGE_BITS_ALL;
315 MPASS(pa[i]->dirty == 0);
316 vm_page_xunbusy(pa[i]);
317 i++;
318 continue;
319 }
320
321 /*
322 * We want to pagein as many pages as possible, limited only
323 * by the 'a' hint and actual request.
324 */
325 count = min(a + 1, npages - i);
326
327 /*
328 * We should not pagein into a valid page, thus we first trim
329 * any valid pages off the end of request, and substitute
330 * to bogus_page those, that are in the middle.
331 */
332 for (j = i + count - 1; j > i; j--) {
333 if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK,
334 xfsize(j, npages, off, len))) {
335 count--;
336 rhpages = 0;
337 } else
338 break;
339 }
340 for (j = i + 1; j < i + count - 1; j++)
341 if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK,
342 xfsize(j, npages, off, len))) {
343 vm_page_xunbusy(pa[j]);
344 SFSTAT_INC(sf_pages_valid);
345 SFSTAT_INC(sf_pages_bogus);
346 pa[j] = bogus_page;
347 }
348
349 refcount_acquire(&sfio->nios);
350 rv = vm_pager_get_pages_async(obj, pa + i, count, NULL,
351 i + count == npages ? &rhpages : NULL,
352 &sendfile_iodone, sfio);
353 if (rv != VM_PAGER_OK) {
354 for (j = i; j < i + count; j++) {
355 if (pa[j] != bogus_page) {
356 vm_page_lock(pa[j]);
357 vm_page_unwire(pa[j], PQ_INACTIVE);
358 vm_page_unlock(pa[j]);
359 }
360 }
361 VM_OBJECT_WUNLOCK(obj);
362 return (EIO);
363 }
364 KASSERT(rv == VM_PAGER_OK, ("%s: pager fail obj %p page %p",
365 __func__, obj, pa[i]));
366
367 SFSTAT_INC(sf_iocnt);
368 SFSTAT_ADD(sf_pages_read, count);
369 if (i + count == npages)
370 SFSTAT_ADD(sf_rhpages_read, rhpages);
371
372 /*
373 * Restore the valid page pointers. They are already
374 * unbusied, but still wired.
375 */
376 for (j = i; j < i + count; j++)
377 if (pa[j] == bogus_page) {
378 pa[j] = vm_page_lookup(obj,
379 OFF_TO_IDX(vmoff(j, off)));
380 KASSERT(pa[j], ("%s: page %p[%d] disappeared",
381 __func__, pa, j));
382
383 }
384 i += count;
385 (*nios)++;
386 }
387
388 VM_OBJECT_WUNLOCK(obj);
389
390 if (*nios == 0 && npages != 0)
391 SFSTAT_INC(sf_noiocnt);
392
393 return (0);
394 }
395
396 static int
sendfile_getobj(struct thread * td,struct file * fp,vm_object_t * obj_res,struct vnode ** vp_res,struct shmfd ** shmfd_res,off_t * obj_size,int * bsize)397 sendfile_getobj(struct thread *td, struct file *fp, vm_object_t *obj_res,
398 struct vnode **vp_res, struct shmfd **shmfd_res, off_t *obj_size,
399 int *bsize)
400 {
401 struct vattr va;
402 vm_object_t obj;
403 struct vnode *vp;
404 struct shmfd *shmfd;
405 int error;
406
407 vp = *vp_res = NULL;
408 obj = NULL;
409 shmfd = *shmfd_res = NULL;
410 *bsize = 0;
411
412 /*
413 * The file descriptor must be a regular file and have a
414 * backing VM object.
415 */
416 if (fp->f_type == DTYPE_VNODE) {
417 vp = fp->f_vnode;
418 vn_lock(vp, LK_SHARED | LK_RETRY);
419 if (vp->v_type != VREG) {
420 error = EINVAL;
421 goto out;
422 }
423 *bsize = vp->v_mount->mnt_stat.f_iosize;
424 error = VOP_GETATTR(vp, &va, td->td_ucred);
425 if (error != 0)
426 goto out;
427 *obj_size = va.va_size;
428 obj = vp->v_object;
429 if (obj == NULL) {
430 error = EINVAL;
431 goto out;
432 }
433 } else if (fp->f_type == DTYPE_SHM) {
434 error = 0;
435 shmfd = fp->f_data;
436 obj = shmfd->shm_object;
437 *obj_size = shmfd->shm_size;
438 } else {
439 error = EINVAL;
440 goto out;
441 }
442
443 VM_OBJECT_WLOCK(obj);
444 if ((obj->flags & OBJ_DEAD) != 0) {
445 VM_OBJECT_WUNLOCK(obj);
446 error = EBADF;
447 goto out;
448 }
449
450 /*
451 * Temporarily increase the backing VM object's reference
452 * count so that a forced reclamation of its vnode does not
453 * immediately destroy it.
454 */
455 vm_object_reference_locked(obj);
456 VM_OBJECT_WUNLOCK(obj);
457 *obj_res = obj;
458 *vp_res = vp;
459 *shmfd_res = shmfd;
460
461 out:
462 if (vp != NULL)
463 VOP_UNLOCK(vp, 0);
464 return (error);
465 }
466
467 static int
sendfile_getsock(struct thread * td,int s,struct file ** sock_fp,struct socket ** so)468 sendfile_getsock(struct thread *td, int s, struct file **sock_fp,
469 struct socket **so)
470 {
471 int error;
472
473 *sock_fp = NULL;
474 *so = NULL;
475
476 /*
477 * The socket must be a stream socket and connected.
478 */
479 error = getsock_cap(td, s, &cap_send_rights,
480 sock_fp, NULL, NULL);
481 if (error != 0)
482 return (error);
483 *so = (*sock_fp)->f_data;
484 if ((*so)->so_type != SOCK_STREAM)
485 return (EINVAL);
486 if (SOLISTENING(*so))
487 return (ENOTCONN);
488 return (0);
489 }
490
491 int
vn_sendfile(struct file * fp,int sockfd,struct uio * hdr_uio,struct uio * trl_uio,off_t offset,size_t nbytes,off_t * sent,int flags,struct thread * td)492 vn_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio,
493 struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags,
494 struct thread *td)
495 {
496 struct file *sock_fp;
497 struct vnode *vp;
498 struct vm_object *obj;
499 struct socket *so;
500 struct mbuf *m, *mh, *mhtail;
501 struct sf_buf *sf;
502 struct shmfd *shmfd;
503 struct sendfile_sync *sfs;
504 struct vattr va;
505 off_t off, sbytes, rem, obj_size;
506 int error, softerr, bsize, hdrlen;
507
508 obj = NULL;
509 so = NULL;
510 m = mh = NULL;
511 sfs = NULL;
512 hdrlen = sbytes = 0;
513 softerr = 0;
514
515 error = sendfile_getobj(td, fp, &obj, &vp, &shmfd, &obj_size, &bsize);
516 if (error != 0)
517 return (error);
518
519 error = sendfile_getsock(td, sockfd, &sock_fp, &so);
520 if (error != 0)
521 goto out;
522
523 #ifdef MAC
524 error = mac_socket_check_send(td->td_ucred, so);
525 if (error != 0)
526 goto out;
527 #endif
528
529 SFSTAT_INC(sf_syscalls);
530 SFSTAT_ADD(sf_rhpages_requested, SF_READAHEAD(flags));
531
532 if (flags & SF_SYNC) {
533 sfs = malloc(sizeof *sfs, M_TEMP, M_WAITOK | M_ZERO);
534 mtx_init(&sfs->mtx, "sendfile", NULL, MTX_DEF);
535 cv_init(&sfs->cv, "sendfile");
536 }
537
538 rem = nbytes ? omin(nbytes, obj_size - offset) : obj_size - offset;
539
540 /*
541 * Protect against multiple writers to the socket.
542 *
543 * XXXRW: Historically this has assumed non-interruptibility, so now
544 * we implement that, but possibly shouldn't.
545 */
546 (void)sblock(&so->so_snd, SBL_WAIT | SBL_NOINTR);
547
548 /*
549 * Loop through the pages of the file, starting with the requested
550 * offset. Get a file page (do I/O if necessary), map the file page
551 * into an sf_buf, attach an mbuf header to the sf_buf, and queue
552 * it on the socket.
553 * This is done in two loops. The inner loop turns as many pages
554 * as it can, up to available socket buffer space, without blocking
555 * into mbufs to have it bulk delivered into the socket send buffer.
556 * The outer loop checks the state and available space of the socket
557 * and takes care of the overall progress.
558 */
559 for (off = offset; rem > 0; ) {
560 struct sf_io *sfio;
561 vm_page_t *pa;
562 struct mbuf *mtail;
563 int nios, space, npages, rhpages;
564
565 mtail = NULL;
566 /*
567 * Check the socket state for ongoing connection,
568 * no errors and space in socket buffer.
569 * If space is low allow for the remainder of the
570 * file to be processed if it fits the socket buffer.
571 * Otherwise block in waiting for sufficient space
572 * to proceed, or if the socket is nonblocking, return
573 * to userland with EAGAIN while reporting how far
574 * we've come.
575 * We wait until the socket buffer has significant free
576 * space to do bulk sends. This makes good use of file
577 * system read ahead and allows packet segmentation
578 * offloading hardware to take over lots of work. If
579 * we were not careful here we would send off only one
580 * sfbuf at a time.
581 */
582 SOCKBUF_LOCK(&so->so_snd);
583 if (so->so_snd.sb_lowat < so->so_snd.sb_hiwat / 2)
584 so->so_snd.sb_lowat = so->so_snd.sb_hiwat / 2;
585 retry_space:
586 if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
587 error = EPIPE;
588 SOCKBUF_UNLOCK(&so->so_snd);
589 goto done;
590 } else if (so->so_error) {
591 error = so->so_error;
592 so->so_error = 0;
593 SOCKBUF_UNLOCK(&so->so_snd);
594 goto done;
595 }
596 if ((so->so_state & SS_ISCONNECTED) == 0) {
597 SOCKBUF_UNLOCK(&so->so_snd);
598 error = ENOTCONN;
599 goto done;
600 }
601
602 space = sbspace(&so->so_snd);
603 if (space < rem &&
604 (space <= 0 ||
605 space < so->so_snd.sb_lowat)) {
606 if (so->so_state & SS_NBIO) {
607 SOCKBUF_UNLOCK(&so->so_snd);
608 error = EAGAIN;
609 goto done;
610 }
611 /*
612 * sbwait drops the lock while sleeping.
613 * When we loop back to retry_space the
614 * state may have changed and we retest
615 * for it.
616 */
617 error = sbwait(&so->so_snd);
618 /*
619 * An error from sbwait usually indicates that we've
620 * been interrupted by a signal. If we've sent anything
621 * then return bytes sent, otherwise return the error.
622 */
623 if (error != 0) {
624 SOCKBUF_UNLOCK(&so->so_snd);
625 goto done;
626 }
627 goto retry_space;
628 }
629 SOCKBUF_UNLOCK(&so->so_snd);
630
631 /*
632 * At the beginning of the first loop check if any headers
633 * are specified and copy them into mbufs. Reduce space in
634 * the socket buffer by the size of the header mbuf chain.
635 * Clear hdr_uio here and hdrlen at the end of the first loop.
636 */
637 if (hdr_uio != NULL && hdr_uio->uio_resid > 0) {
638 hdr_uio->uio_td = td;
639 hdr_uio->uio_rw = UIO_WRITE;
640 mh = m_uiotombuf(hdr_uio, M_WAITOK, space, 0, 0);
641 hdrlen = m_length(mh, &mhtail);
642 space -= hdrlen;
643 /*
644 * If header consumed all the socket buffer space,
645 * don't waste CPU cycles and jump to the end.
646 */
647 if (space == 0) {
648 sfio = NULL;
649 nios = 0;
650 goto prepend_header;
651 }
652 hdr_uio = NULL;
653 }
654
655 if (vp != NULL) {
656 error = vn_lock(vp, LK_SHARED);
657 if (error != 0)
658 goto done;
659 error = VOP_GETATTR(vp, &va, td->td_ucred);
660 if (error != 0 || off >= va.va_size) {
661 VOP_UNLOCK(vp, 0);
662 goto done;
663 }
664 if (va.va_size != obj_size) {
665 obj_size = va.va_size;
666 rem = nbytes ?
667 omin(nbytes + offset, obj_size) : obj_size;
668 rem -= off;
669 }
670 }
671
672 if (space > rem)
673 space = rem;
674
675 npages = howmany(space + (off & PAGE_MASK), PAGE_SIZE);
676
677 /*
678 * Calculate maximum allowed number of pages for readahead
679 * at this iteration. If SF_USER_READAHEAD was set, we don't
680 * do any heuristics and use exactly the value supplied by
681 * application. Otherwise, we allow readahead up to "rem".
682 * If application wants more, let it be, but there is no
683 * reason to go above MAXPHYS. Also check against "obj_size",
684 * since vm_pager_has_page() can hint beyond EOF.
685 */
686 if (flags & SF_USER_READAHEAD) {
687 rhpages = SF_READAHEAD(flags);
688 } else {
689 rhpages = howmany(rem + (off & PAGE_MASK), PAGE_SIZE) -
690 npages;
691 rhpages += SF_READAHEAD(flags);
692 }
693 rhpages = min(howmany(MAXPHYS, PAGE_SIZE), rhpages);
694 rhpages = min(howmany(obj_size - trunc_page(off), PAGE_SIZE) -
695 npages, rhpages);
696
697 sfio = malloc(sizeof(struct sf_io) +
698 npages * sizeof(vm_page_t), M_TEMP, M_WAITOK);
699 refcount_init(&sfio->nios, 1);
700 sfio->so = so;
701 sfio->error = 0;
702
703 error = sendfile_swapin(obj, sfio, &nios, off, space, npages,
704 rhpages, flags);
705 if (error != 0) {
706 if (vp != NULL)
707 VOP_UNLOCK(vp, 0);
708 free(sfio, M_TEMP);
709 goto done;
710 }
711
712 /*
713 * Loop and construct maximum sized mbuf chain to be bulk
714 * dumped into socket buffer.
715 */
716 pa = sfio->pa;
717 for (int i = 0; i < npages; i++) {
718 struct mbuf *m0;
719
720 /*
721 * If a page wasn't grabbed successfully, then
722 * trim the array. Can happen only with SF_NODISKIO.
723 */
724 if (pa[i] == NULL) {
725 SFSTAT_INC(sf_busy);
726 fixspace(npages, i, off, &space);
727 npages = i;
728 softerr = EBUSY;
729 break;
730 }
731
732 /*
733 * Get a sendfile buf. When allocating the
734 * first buffer for mbuf chain, we usually
735 * wait as long as necessary, but this wait
736 * can be interrupted. For consequent
737 * buffers, do not sleep, since several
738 * threads might exhaust the buffers and then
739 * deadlock.
740 */
741 sf = sf_buf_alloc(pa[i],
742 m != NULL ? SFB_NOWAIT : SFB_CATCH);
743 if (sf == NULL) {
744 SFSTAT_INC(sf_allocfail);
745 for (int j = i; j < npages; j++) {
746 vm_page_lock(pa[j]);
747 vm_page_unwire(pa[j], PQ_INACTIVE);
748 vm_page_unlock(pa[j]);
749 }
750 if (m == NULL)
751 softerr = ENOBUFS;
752 fixspace(npages, i, off, &space);
753 npages = i;
754 break;
755 }
756
757 m0 = m_get(M_WAITOK, MT_DATA);
758 m0->m_ext.ext_buf = (char *)sf_buf_kva(sf);
759 m0->m_ext.ext_size = PAGE_SIZE;
760 m0->m_ext.ext_arg1 = sf;
761 m0->m_ext.ext_type = EXT_SFBUF;
762 m0->m_ext.ext_flags = EXT_FLAG_EMBREF;
763 m0->m_ext.ext_free = sendfile_free_mext;
764 /*
765 * SF_NOCACHE sets the page as being freed upon send.
766 * However, we ignore it for the last page in 'space',
767 * if the page is truncated, and we got more data to
768 * send (rem > space), or if we have readahead
769 * configured (rhpages > 0).
770 */
771 if ((flags & SF_NOCACHE) &&
772 (i != npages - 1 ||
773 !((off + space) & PAGE_MASK) ||
774 !(rem > space || rhpages > 0)))
775 m0->m_ext.ext_flags |= EXT_FLAG_NOCACHE;
776 if (sfs != NULL) {
777 m0->m_ext.ext_flags |= EXT_FLAG_SYNC;
778 m0->m_ext.ext_arg2 = sfs;
779 mtx_lock(&sfs->mtx);
780 sfs->count++;
781 mtx_unlock(&sfs->mtx);
782 }
783 m0->m_ext.ext_count = 1;
784 m0->m_flags |= (M_EXT | M_RDONLY);
785 if (nios)
786 m0->m_flags |= M_NOTREADY;
787 m0->m_data = (char *)sf_buf_kva(sf) +
788 (vmoff(i, off) & PAGE_MASK);
789 m0->m_len = xfsize(i, npages, off, space);
790
791 if (i == 0)
792 sfio->m = m0;
793
794 /* Append to mbuf chain. */
795 if (mtail != NULL)
796 mtail->m_next = m0;
797 else
798 m = m0;
799 mtail = m0;
800 }
801
802 if (vp != NULL)
803 VOP_UNLOCK(vp, 0);
804
805 /* Keep track of bytes processed. */
806 off += space;
807 rem -= space;
808
809 /* Prepend header, if any. */
810 if (hdrlen) {
811 prepend_header:
812 mhtail->m_next = m;
813 m = mh;
814 mh = NULL;
815 }
816
817 if (m == NULL) {
818 KASSERT(softerr, ("%s: m NULL, no error", __func__));
819 error = softerr;
820 free(sfio, M_TEMP);
821 goto done;
822 }
823
824 /* Add the buffer chain to the socket buffer. */
825 KASSERT(m_length(m, NULL) == space + hdrlen,
826 ("%s: mlen %u space %d hdrlen %d",
827 __func__, m_length(m, NULL), space, hdrlen));
828
829 CURVNET_SET(so->so_vnet);
830 if (nios == 0) {
831 /*
832 * If sendfile_swapin() didn't initiate any I/Os,
833 * which happens if all data is cached in VM, then
834 * we can send data right now without the
835 * PRUS_NOTREADY flag.
836 */
837 free(sfio, M_TEMP);
838 error = (*so->so_proto->pr_usrreqs->pru_send)
839 (so, 0, m, NULL, NULL, td);
840 } else {
841 sfio->npages = npages;
842 soref(so);
843 error = (*so->so_proto->pr_usrreqs->pru_send)
844 (so, PRUS_NOTREADY, m, NULL, NULL, td);
845 sendfile_iodone(sfio, NULL, 0, 0);
846 }
847 CURVNET_RESTORE();
848
849 m = NULL; /* pru_send always consumes */
850 if (error)
851 goto done;
852 sbytes += space + hdrlen;
853 if (hdrlen)
854 hdrlen = 0;
855 if (softerr) {
856 error = softerr;
857 goto done;
858 }
859 }
860
861 /*
862 * Send trailers. Wimp out and use writev(2).
863 */
864 if (trl_uio != NULL) {
865 sbunlock(&so->so_snd);
866 error = kern_writev(td, sockfd, trl_uio);
867 if (error == 0)
868 sbytes += td->td_retval[0];
869 goto out;
870 }
871
872 done:
873 sbunlock(&so->so_snd);
874 out:
875 /*
876 * If there was no error we have to clear td->td_retval[0]
877 * because it may have been set by writev.
878 */
879 if (error == 0) {
880 td->td_retval[0] = 0;
881 }
882 if (sent != NULL) {
883 (*sent) = sbytes;
884 }
885 if (obj != NULL)
886 vm_object_deallocate(obj);
887 if (so)
888 fdrop(sock_fp, td);
889 if (m)
890 m_freem(m);
891 if (mh)
892 m_freem(mh);
893
894 if (sfs != NULL) {
895 mtx_lock(&sfs->mtx);
896 if (sfs->count != 0)
897 cv_wait(&sfs->cv, &sfs->mtx);
898 KASSERT(sfs->count == 0, ("sendfile sync still busy"));
899 cv_destroy(&sfs->cv);
900 mtx_destroy(&sfs->mtx);
901 free(sfs, M_TEMP);
902 }
903
904 if (error == ERESTART)
905 error = EINTR;
906
907 return (error);
908 }
909
910 static int
sendfile(struct thread * td,struct sendfile_args * uap,int compat)911 sendfile(struct thread *td, struct sendfile_args *uap, int compat)
912 {
913 struct sf_hdtr hdtr;
914 struct uio *hdr_uio, *trl_uio;
915 struct file *fp;
916 off_t sbytes;
917 int error;
918
919 /*
920 * File offset must be positive. If it goes beyond EOF
921 * we send only the header/trailer and no payload data.
922 */
923 if (uap->offset < 0)
924 return (EINVAL);
925
926 sbytes = 0;
927 hdr_uio = trl_uio = NULL;
928
929 if (uap->hdtr != NULL) {
930 error = copyin(uap->hdtr, &hdtr, sizeof(hdtr));
931 if (error != 0)
932 goto out;
933 if (hdtr.headers != NULL) {
934 error = copyinuio(hdtr.headers, hdtr.hdr_cnt,
935 &hdr_uio);
936 if (error != 0)
937 goto out;
938 #ifdef COMPAT_FREEBSD4
939 /*
940 * In FreeBSD < 5.0 the nbytes to send also included
941 * the header. If compat is specified subtract the
942 * header size from nbytes.
943 */
944 if (compat) {
945 if (uap->nbytes > hdr_uio->uio_resid)
946 uap->nbytes -= hdr_uio->uio_resid;
947 else
948 uap->nbytes = 0;
949 }
950 #endif
951 }
952 if (hdtr.trailers != NULL) {
953 error = copyinuio(hdtr.trailers, hdtr.trl_cnt,
954 &trl_uio);
955 if (error != 0)
956 goto out;
957 }
958 }
959
960 AUDIT_ARG_FD(uap->fd);
961
962 /*
963 * sendfile(2) can start at any offset within a file so we require
964 * CAP_READ+CAP_SEEK = CAP_PREAD.
965 */
966 if ((error = fget_read(td, uap->fd, &cap_pread_rights, &fp)) != 0)
967 goto out;
968
969 error = fo_sendfile(fp, uap->s, hdr_uio, trl_uio, uap->offset,
970 uap->nbytes, &sbytes, uap->flags, td);
971 fdrop(fp, td);
972
973 if (uap->sbytes != NULL)
974 copyout(&sbytes, uap->sbytes, sizeof(off_t));
975
976 out:
977 free(hdr_uio, M_IOV);
978 free(trl_uio, M_IOV);
979 return (error);
980 }
981
982 /*
983 * sendfile(2)
984 *
985 * int sendfile(int fd, int s, off_t offset, size_t nbytes,
986 * struct sf_hdtr *hdtr, off_t *sbytes, int flags)
987 *
988 * Send a file specified by 'fd' and starting at 'offset' to a socket
989 * specified by 's'. Send only 'nbytes' of the file or until EOF if nbytes ==
990 * 0. Optionally add a header and/or trailer to the socket output. If
991 * specified, write the total number of bytes sent into *sbytes.
992 */
993 int
sys_sendfile(struct thread * td,struct sendfile_args * uap)994 sys_sendfile(struct thread *td, struct sendfile_args *uap)
995 {
996
997 return (sendfile(td, uap, 0));
998 }
999
1000 #ifdef COMPAT_FREEBSD4
1001 int
freebsd4_sendfile(struct thread * td,struct freebsd4_sendfile_args * uap)1002 freebsd4_sendfile(struct thread *td, struct freebsd4_sendfile_args *uap)
1003 {
1004 struct sendfile_args args;
1005
1006 args.fd = uap->fd;
1007 args.s = uap->s;
1008 args.offset = uap->offset;
1009 args.nbytes = uap->nbytes;
1010 args.hdtr = uap->hdtr;
1011 args.sbytes = uap->sbytes;
1012 args.flags = uap->flags;
1013
1014 return (sendfile(td, &args, 1));
1015 }
1016 #endif /* COMPAT_FREEBSD4 */
1017