xref: /freebsd/sys/kern/kern_sendfile.c (revision 314cb279959b08811543612a715e47266f685c7b)
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 #include "opt_kern_tls.h"
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/ktls.h>
39 #include <sys/mutex.h>
40 #include <sys/malloc.h>
41 #include <sys/mman.h>
42 #include <sys/mount.h>
43 #include <sys/mbuf.h>
44 #include <sys/proc.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/sysproto.h>
53 #include <sys/vnode.h>
54 
55 #include <net/vnet.h>
56 #include <netinet/in.h>
57 #include <netinet/tcp.h>
58 #include <netinet/in_pcb.h>
59 #include <netinet/tcp_var.h>
60 #include <netinet/tcp_log_buf.h>
61 
62 #include <security/audit/audit.h>
63 #include <security/mac/mac_framework.h>
64 
65 #include <vm/vm.h>
66 #include <vm/vm_object.h>
67 #include <vm/vm_pager.h>
68 
69 static MALLOC_DEFINE(M_SENDFILE, "sendfile", "sendfile dynamic memory");
70 
71 #define	EXT_FLAG_SYNC		EXT_FLAG_VENDOR1
72 #define	EXT_FLAG_NOCACHE	EXT_FLAG_VENDOR2
73 #define	EXT_FLAG_CACHE_LAST	EXT_FLAG_VENDOR3
74 
75 /*
76  * Structure describing a single sendfile(2) I/O, which may consist of
77  * several underlying pager I/Os.
78  *
79  * The syscall context allocates the structure and initializes 'nios'
80  * to 1.  As sendfile_swapin() runs through pages and starts asynchronous
81  * paging operations, it increments 'nios'.
82  *
83  * Every I/O completion calls sendfile_iodone(), which decrements the 'nios',
84  * and the syscall also calls sendfile_iodone() after allocating all mbufs,
85  * linking them and sending to socket.  Whoever reaches zero 'nios' is
86  * responsible to * call pru_ready on the socket, to notify it of readyness
87  * of the data.
88  */
89 struct sf_io {
90 	volatile u_int	nios;
91 	u_int		error;
92 	int		npages;
93 	struct socket	*so;
94 	struct mbuf	*m;
95 	vm_object_t	obj;
96 	vm_pindex_t	pindex0;
97 #ifdef KERN_TLS
98 	struct ktls_session *tls;
99 #endif
100 	vm_page_t	pa[];
101 };
102 
103 /*
104  * Structure used to track requests with SF_SYNC flag.
105  */
106 struct sendfile_sync {
107 	struct mtx	mtx;
108 	struct cv	cv;
109 	unsigned	count;
110 	bool		waiting;
111 };
112 
113 static void
sendfile_sync_destroy(struct sendfile_sync * sfs)114 sendfile_sync_destroy(struct sendfile_sync *sfs)
115 {
116 	KASSERT(sfs->count == 0, ("sendfile sync %p still busy", sfs));
117 
118 	cv_destroy(&sfs->cv);
119 	mtx_destroy(&sfs->mtx);
120 	free(sfs, M_SENDFILE);
121 }
122 
123 static void
sendfile_sync_signal(struct sendfile_sync * sfs)124 sendfile_sync_signal(struct sendfile_sync *sfs)
125 {
126 	mtx_lock(&sfs->mtx);
127 	KASSERT(sfs->count > 0, ("sendfile sync %p not busy", sfs));
128 	if (--sfs->count == 0) {
129 		if (!sfs->waiting) {
130 			/* The sendfile() waiter was interrupted by a signal. */
131 			sendfile_sync_destroy(sfs);
132 			return;
133 		} else {
134 			cv_signal(&sfs->cv);
135 		}
136 	}
137 	mtx_unlock(&sfs->mtx);
138 }
139 
140 counter_u64_t sfstat[sizeof(struct sfstat) / sizeof(uint64_t)];
141 
142 static void
sfstat_init(const void * unused)143 sfstat_init(const void *unused)
144 {
145 
146 	COUNTER_ARRAY_ALLOC(sfstat, sizeof(struct sfstat) / sizeof(uint64_t),
147 	    M_WAITOK);
148 }
149 SYSINIT(sfstat, SI_SUB_MBUF, SI_ORDER_FIRST, sfstat_init, NULL);
150 
151 static int
sfstat_sysctl(SYSCTL_HANDLER_ARGS)152 sfstat_sysctl(SYSCTL_HANDLER_ARGS)
153 {
154 	struct sfstat s;
155 
156 	COUNTER_ARRAY_COPY(sfstat, &s, sizeof(s) / sizeof(uint64_t));
157 	if (req->newptr)
158 		COUNTER_ARRAY_ZERO(sfstat, sizeof(s) / sizeof(uint64_t));
159 	return (SYSCTL_OUT(req, &s, sizeof(s)));
160 }
161 SYSCTL_PROC(_kern_ipc, OID_AUTO, sfstat,
162     CTLTYPE_OPAQUE | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0,
163     sfstat_sysctl, "I",
164     "sendfile statistics");
165 
166 static void
sendfile_free_mext(struct mbuf * m)167 sendfile_free_mext(struct mbuf *m)
168 {
169 	struct sf_buf *sf;
170 	vm_page_t pg;
171 	int flags;
172 
173 	KASSERT(m->m_flags & M_EXT && m->m_ext.ext_type == EXT_SFBUF,
174 	    ("%s: m %p !M_EXT or !EXT_SFBUF", __func__, m));
175 
176 	sf = m->m_ext.ext_arg1;
177 	pg = sf_buf_page(sf);
178 	flags = (m->m_ext.ext_flags & EXT_FLAG_NOCACHE) != 0 ? VPR_TRYFREE : 0;
179 
180 	sf_buf_free(sf);
181 	vm_page_release(pg, flags);
182 
183 	if (m->m_ext.ext_flags & EXT_FLAG_SYNC) {
184 		struct sendfile_sync *sfs = m->m_ext.ext_arg2;
185 		sendfile_sync_signal(sfs);
186 	}
187 }
188 
189 static void
sendfile_free_mext_pg(struct mbuf * m)190 sendfile_free_mext_pg(struct mbuf *m)
191 {
192 	vm_page_t pg;
193 	int flags, i;
194 	bool cache_last;
195 
196 	M_ASSERTEXTPG(m);
197 
198 	cache_last = m->m_ext.ext_flags & EXT_FLAG_CACHE_LAST;
199 	flags = (m->m_ext.ext_flags & EXT_FLAG_NOCACHE) != 0 ? VPR_TRYFREE : 0;
200 
201 	for (i = 0; i < m->m_epg_npgs; i++) {
202 		if (cache_last && i == m->m_epg_npgs - 1)
203 			flags = 0;
204 		pg = PHYS_TO_VM_PAGE(m->m_epg_pa[i]);
205 		vm_page_release(pg, flags);
206 	}
207 
208 	if (m->m_ext.ext_flags & EXT_FLAG_SYNC) {
209 		struct sendfile_sync *sfs = m->m_ext.ext_arg1;
210 		sendfile_sync_signal(sfs);
211 	}
212 }
213 
214 /*
215  * Helper function to calculate how much data to put into page i of n.
216  * Only first and last pages are special.
217  */
218 static inline off_t
xfsize(int i,int n,off_t off,off_t len)219 xfsize(int i, int n, off_t off, off_t len)
220 {
221 
222 	if (i == 0)
223 		return (omin(PAGE_SIZE - (off & PAGE_MASK), len));
224 
225 	if (i == n - 1 && ((off + len) & PAGE_MASK) > 0)
226 		return ((off + len) & PAGE_MASK);
227 
228 	return (PAGE_SIZE);
229 }
230 
231 /*
232  * Helper function to get offset within object for i page.
233  */
234 static inline vm_ooffset_t
vmoff(int i,off_t off)235 vmoff(int i, off_t off)
236 {
237 
238 	if (i == 0)
239 		return ((vm_ooffset_t)off);
240 
241 	return (trunc_page(off + i * PAGE_SIZE));
242 }
243 
244 /*
245  * Helper function used when allocation of a page or sf_buf failed.
246  * Pretend as if we don't have enough space, subtract xfsize() of
247  * all pages that failed.
248  */
249 static inline void
fixspace(int old,int new,off_t off,int * space)250 fixspace(int old, int new, off_t off, int *space)
251 {
252 
253 	KASSERT(old > new, ("%s: old %d new %d", __func__, old, new));
254 
255 	/* Subtract last one. */
256 	*space -= xfsize(old - 1, old, off, *space);
257 	old--;
258 
259 	if (new == old)
260 		/* There was only one page. */
261 		return;
262 
263 	/* Subtract first one. */
264 	if (new == 0) {
265 		*space -= xfsize(0, old, off, *space);
266 		new++;
267 	}
268 
269 	/* Rest of pages are full sized. */
270 	*space -= (old - new) * PAGE_SIZE;
271 
272 	KASSERT(*space >= 0, ("%s: space went backwards", __func__));
273 }
274 
275 /*
276  * Wait for all in-flight ios to complete, we must not unwire pages
277  * under them.
278  */
279 static void
sendfile_iowait(struct sf_io * sfio,const char * wmesg)280 sendfile_iowait(struct sf_io *sfio, const char *wmesg)
281 {
282 	while (atomic_load_int(&sfio->nios) != 1)
283 		pause(wmesg, 1);
284 }
285 
286 /*
287  * I/O completion callback.
288  */
289 static void
sendfile_iodone(void * arg,vm_page_t * pa,int count,int error)290 sendfile_iodone(void *arg, vm_page_t *pa, int count, int error)
291 {
292 	struct sf_io *sfio = arg;
293 	struct socket *so;
294 	int i;
295 
296 	if (error != 0)
297 		sfio->error = error;
298 
299 	/*
300 	 * Restore the valid page pointers.  They are already
301 	 * unbusied, but still wired.
302 	 *
303 	 * XXXKIB since pages are only wired, and we do not
304 	 * own the object lock, other users might have
305 	 * invalidated them in meantime.  Similarly, after we
306 	 * unbusied the swapped-in pages, they can become
307 	 * invalid under us.
308 	 */
309 	MPASS(count == 0 || pa[0] != bogus_page);
310 	for (i = 0; i < count; i++) {
311 		if (pa[i] == bogus_page) {
312 			sfio->pa[(pa[0]->pindex - sfio->pindex0) + i] =
313 			    pa[i] = vm_page_relookup(sfio->obj,
314 			    pa[0]->pindex + i);
315 			KASSERT(pa[i] != NULL,
316 			    ("%s: page %p[%d] disappeared",
317 			    __func__, pa, i));
318 		} else {
319 			vm_page_xunbusy_unchecked(pa[i]);
320 		}
321 	}
322 
323 	if (!refcount_release(&sfio->nios))
324 		return;
325 
326 #ifdef INVARIANTS
327 	for (i = 1; i < sfio->npages; i++) {
328 		if (sfio->pa[i] == NULL)
329 			break;
330 		KASSERT(vm_page_wired(sfio->pa[i]),
331 		    ("sfio %p page %d %p not wired", sfio, i, sfio->pa[i]));
332 		if (i == 0)
333 			continue;
334 		KASSERT(sfio->pa[0]->object == sfio->pa[i]->object,
335 		    ("sfio %p page %d %p wrong owner %p %p", sfio, i,
336 		    sfio->pa[i], sfio->pa[0]->object, sfio->pa[i]->object));
337 		KASSERT(sfio->pa[0]->pindex + i == sfio->pa[i]->pindex,
338 		    ("sfio %p page %d %p wrong index %jx %jx", sfio, i,
339 		    sfio->pa[i], (uintmax_t)sfio->pa[0]->pindex,
340 		    (uintmax_t)sfio->pa[i]->pindex));
341 	}
342 #endif
343 
344 	vm_object_pip_wakeup(sfio->obj);
345 
346 	if (sfio->m == NULL) {
347 		/*
348 		 * Either I/O operation failed, or we failed to allocate
349 		 * buffers, or we bailed out on first busy page, or we
350 		 * succeeded filling the request without any I/Os. Anyway,
351 		 * pru_send hadn't been executed - nothing had been sent
352 		 * to the socket yet.
353 		 */
354 		MPASS((curthread->td_pflags & TDP_KTHREAD) == 0);
355 		free(sfio, M_SENDFILE);
356 		return;
357 	}
358 
359 #if defined(KERN_TLS) && defined(INVARIANTS)
360 	if ((sfio->m->m_flags & M_EXTPG) != 0)
361 		KASSERT(sfio->tls == sfio->m->m_epg_tls,
362 		    ("TLS session mismatch"));
363 	else
364 		KASSERT(sfio->tls == NULL,
365 		    ("non-ext_pgs mbuf with TLS session"));
366 #endif
367 	so = sfio->so;
368 	CURVNET_SET(so->so_vnet);
369 	if (__predict_false(sfio->error)) {
370 		/*
371 		 * I/O operation failed.  The state of data in the socket
372 		 * is now inconsistent, and all what we can do is to tear
373 		 * it down. Protocol abort method would tear down protocol
374 		 * state, free all ready mbufs and detach not ready ones.
375 		 * We will free the mbufs corresponding to this I/O manually.
376 		 *
377 		 * The socket would be marked with EIO and made available
378 		 * for read, so that application receives EIO on next
379 		 * syscall and eventually closes the socket.
380 		 */
381 		so->so_proto->pr_abort(so);
382 		so->so_error = EIO;
383 
384 		mb_free_notready(sfio->m, sfio->npages);
385 #ifdef KERN_TLS
386 	} else if (sfio->tls != NULL && sfio->tls->mode == TCP_TLS_MODE_SW) {
387 		/*
388 		 * I/O operation is complete, but we still need to
389 		 * encrypt.  We cannot do this in the interrupt thread
390 		 * of the disk controller, so forward the mbufs to a
391 		 * different thread.
392 		 *
393 		 * Donate the socket reference from sfio to rather
394 		 * than explicitly invoking soref().
395 		 */
396 		ktls_enqueue(sfio->m, so, sfio->npages);
397 		goto out_with_ref;
398 #endif
399 	} else
400 		(void)so->so_proto->pr_ready(so, sfio->m, sfio->npages);
401 
402 	sorele(so);
403 #ifdef KERN_TLS
404 out_with_ref:
405 #endif
406 	CURVNET_RESTORE();
407 	free(sfio, M_SENDFILE);
408 }
409 
410 /*
411  * Iterate through pages vector and request paging for non-valid pages.
412  */
413 static int
sendfile_swapin(vm_object_t obj,struct sf_io * sfio,int * nios,off_t off,off_t len,int rhpages,int flags)414 sendfile_swapin(vm_object_t obj, struct sf_io *sfio, int *nios, off_t off,
415     off_t len, int rhpages, int flags)
416 {
417 	vm_page_t *pa;
418 	int a, count, count1, grabbed, i, j, npages, rv;
419 
420 	pa = sfio->pa;
421 	npages = sfio->npages;
422 	*nios = 0;
423 	flags = (flags & SF_NODISKIO) ? VM_ALLOC_NOWAIT : 0;
424 	sfio->pindex0 = OFF_TO_IDX(off);
425 
426 	/*
427 	 * First grab all the pages and wire them.  Note that we grab
428 	 * only required pages.  Readahead pages are dealt with later.
429 	 */
430 	grabbed = vm_page_grab_pages_unlocked(obj, OFF_TO_IDX(off),
431 	    VM_ALLOC_NORMAL | VM_ALLOC_WIRED | flags, pa, npages);
432 	if (grabbed < npages) {
433 		for (int i = grabbed; i < npages; i++)
434 			pa[i] = NULL;
435 		npages = grabbed;
436 		rhpages = 0;
437 	}
438 
439 	for (i = 0; i < npages;) {
440 		/* Skip valid pages. */
441 		if (vm_page_is_valid(pa[i], vmoff(i, off) & PAGE_MASK,
442 		    xfsize(i, npages, off, len))) {
443 			vm_page_xunbusy(pa[i]);
444 			SFSTAT_INC(sf_pages_valid);
445 			i++;
446 			continue;
447 		}
448 
449 		/*
450 		 * Next page is invalid.  Check if it belongs to pager.  It
451 		 * may not be there, which is a regular situation for shmem
452 		 * pager.  For vnode pager this happens only in case of
453 		 * a sparse file.
454 		 *
455 		 * Important feature of vm_pager_has_page() is the hint
456 		 * stored in 'a', about how many pages we can pagein after
457 		 * this page in a single I/O.
458 		 */
459 		VM_OBJECT_RLOCK(obj);
460 		if (!vm_pager_has_page(obj, OFF_TO_IDX(vmoff(i, off)), NULL,
461 		    &a)) {
462 			VM_OBJECT_RUNLOCK(obj);
463 			pmap_zero_page(pa[i]);
464 			vm_page_valid(pa[i]);
465 			MPASS(pa[i]->dirty == 0);
466 			vm_page_xunbusy(pa[i]);
467 			i++;
468 			continue;
469 		}
470 		VM_OBJECT_RUNLOCK(obj);
471 
472 		/*
473 		 * We want to pagein as many pages as possible, limited only
474 		 * by the 'a' hint and actual request.
475 		 */
476 		count = min(a + 1, npages - i);
477 
478 		/*
479 		 * We should not pagein into a valid page because
480 		 * there might be still unfinished write tracked by
481 		 * e.g. a buffer, thus we substitute any valid pages
482 		 * with the bogus one.
483 		 *
484 		 * We must not leave around xbusy pages which are not
485 		 * part of the run passed to vm_pager_getpages(),
486 		 * otherwise pager might deadlock waiting for the busy
487 		 * status of the page, e.g. if it constitues the
488 		 * buffer needed to validate other page.
489 		 *
490 		 * First trim the end of the run consisting of the
491 		 * valid pages, then replace the rest of the valid
492 		 * with bogus.
493 		 */
494 		count1 = count;
495 		for (j = i + count - 1; j > i; j--) {
496 			if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK,
497 			    xfsize(j, npages, off, len))) {
498 				vm_page_xunbusy(pa[j]);
499 				SFSTAT_INC(sf_pages_valid);
500 				count--;
501 			} else {
502 				break;
503 			}
504 		}
505 
506 		/*
507 		 * The last page in the run pa[i + count - 1] is
508 		 * guaranteed to be invalid by the trim above, so it
509 		 * is not replaced with bogus, thus -1 in the loop end
510 		 * condition.
511 		 */
512 		MPASS(pa[i + count - 1]->valid != VM_PAGE_BITS_ALL);
513 		for (j = i + 1; j < i + count - 1; j++) {
514 			if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK,
515 			    xfsize(j, npages, off, len))) {
516 				vm_page_xunbusy(pa[j]);
517 				SFSTAT_INC(sf_pages_valid);
518 				SFSTAT_INC(sf_pages_bogus);
519 				pa[j] = bogus_page;
520 			}
521 		}
522 
523 		refcount_acquire(&sfio->nios);
524 		rv = vm_pager_get_pages_async(obj, pa + i, count, NULL,
525 		    i + count == npages ? &rhpages : NULL,
526 		    &sendfile_iodone, sfio);
527 		if (__predict_false(rv != VM_PAGER_OK)) {
528 			sendfile_iowait(sfio, "sferrio");
529 
530 			/*
531 			 * Do remaining pages recovery before returning EIO.
532 			 * Pages from 0 to npages are wired.
533 			 * Pages from (i + count1) to npages are busied.
534 			 */
535 			for (j = 0; j < npages; j++) {
536 				if (j >= i + count1)
537 					vm_page_xunbusy(pa[j]);
538 				KASSERT(pa[j] != NULL && pa[j] != bogus_page,
539 				    ("%s: page %p[%d] I/O recovery failure",
540 				    __func__, pa, j));
541 				vm_page_unwire(pa[j], PQ_INACTIVE);
542 				pa[j] = NULL;
543 			}
544 			return (EIO);
545 		}
546 
547 		SFSTAT_INC(sf_iocnt);
548 		SFSTAT_ADD(sf_pages_read, count);
549 		if (i + count == npages)
550 			SFSTAT_ADD(sf_rhpages_read, rhpages);
551 
552 		i += count1;
553 		(*nios)++;
554 	}
555 
556 	if (*nios == 0 && npages != 0)
557 		SFSTAT_INC(sf_noiocnt);
558 
559 	return (0);
560 }
561 
562 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)563 sendfile_getobj(struct thread *td, struct file *fp, vm_object_t *obj_res,
564     struct vnode **vp_res, struct shmfd **shmfd_res, off_t *obj_size,
565     int *bsize)
566 {
567 	vm_object_t obj;
568 	struct vnode *vp;
569 	struct shmfd *shmfd;
570 	int error;
571 
572 	error = 0;
573 	vp = *vp_res = NULL;
574 	obj = NULL;
575 	shmfd = *shmfd_res = NULL;
576 	*bsize = 0;
577 
578 	/*
579 	 * The file descriptor must be a regular file and have a
580 	 * backing VM object.
581 	 */
582 	if (fp->f_type == DTYPE_VNODE) {
583 		vp = fp->f_vnode;
584 		vn_lock(vp, LK_SHARED | LK_RETRY);
585 		if (vp->v_type != VREG) {
586 			error = EINVAL;
587 			goto out;
588 		}
589 		*bsize = vp->v_mount->mnt_stat.f_iosize;
590 		obj = vp->v_object;
591 		if (obj == NULL) {
592 			error = EINVAL;
593 			goto out;
594 		}
595 
596 		/*
597 		 * Use the pager size when available to simplify synchronization
598 		 * with filesystems, which otherwise must atomically update both
599 		 * the vnode pager size and file size.
600 		 */
601 		if (obj->type == OBJT_VNODE) {
602 			VM_OBJECT_RLOCK(obj);
603 			*obj_size = obj->un_pager.vnp.vnp_size;
604 		} else {
605 			error = vn_getsize_locked(vp, obj_size, td->td_ucred);
606 			if (error != 0)
607 				goto out;
608 			VM_OBJECT_RLOCK(obj);
609 		}
610 	} else if (fp->f_type == DTYPE_SHM) {
611 		shmfd = fp->f_data;
612 		obj = shmfd->shm_object;
613 		VM_OBJECT_RLOCK(obj);
614 		*obj_size = shmfd->shm_size;
615 	} else {
616 		error = EINVAL;
617 		goto out;
618 	}
619 
620 	if ((obj->flags & OBJ_DEAD) != 0) {
621 		VM_OBJECT_RUNLOCK(obj);
622 		error = EBADF;
623 		goto out;
624 	}
625 
626 	/*
627 	 * Temporarily increase the backing VM object's reference
628 	 * count so that a forced reclamation of its vnode does not
629 	 * immediately destroy it.
630 	 */
631 	vm_object_reference_locked(obj);
632 	VM_OBJECT_RUNLOCK(obj);
633 	*obj_res = obj;
634 	*vp_res = vp;
635 	*shmfd_res = shmfd;
636 
637 out:
638 	if (vp != NULL)
639 		VOP_UNLOCK(vp);
640 	return (error);
641 }
642 
643 static int
sendfile_getsock(struct thread * td,int s,struct file ** sock_fp,struct socket ** so)644 sendfile_getsock(struct thread *td, int s, struct file **sock_fp,
645     struct socket **so)
646 {
647 	int error;
648 
649 	*sock_fp = NULL;
650 	*so = NULL;
651 
652 	/*
653 	 * The socket must be a stream socket and connected.
654 	 */
655 	error = getsock(td, s, &cap_send_rights, sock_fp);
656 	if (error != 0)
657 		return (error);
658 	*so = (*sock_fp)->f_data;
659 	if ((*so)->so_type != SOCK_STREAM)
660 		return (EINVAL);
661 	/*
662 	 * SCTP one-to-one style sockets currently don't work with
663 	 * sendfile(). So indicate EINVAL for now.
664 	 */
665 	if ((*so)->so_proto->pr_protocol == IPPROTO_SCTP)
666 		return (EINVAL);
667 	return (0);
668 }
669 
670 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)671 vn_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio,
672     struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags,
673     struct thread *td)
674 {
675 	struct file *sock_fp;
676 	struct vnode *vp;
677 	struct vm_object *obj;
678 	vm_page_t pga;
679 	struct socket *so;
680 #ifdef KERN_TLS
681 	struct ktls_session *tls;
682 #endif
683 	struct mbuf *m, *mh, *mhtail;
684 	struct sf_buf *sf;
685 	struct shmfd *shmfd;
686 	struct sendfile_sync *sfs;
687 	struct vattr va;
688 	off_t off, sbytes, rem, obj_size, nobj_size;
689 	int bsize, error, ext_pgs_idx, hdrlen, max_pgs, softerr;
690 #ifdef KERN_TLS
691 	int tls_enq_cnt;
692 #endif
693 	bool use_ext_pgs;
694 
695 	obj = NULL;
696 	so = NULL;
697 	m = mh = NULL;
698 	sfs = NULL;
699 #ifdef KERN_TLS
700 	tls = NULL;
701 #endif
702 	hdrlen = sbytes = 0;
703 	softerr = 0;
704 	use_ext_pgs = false;
705 
706 	error = sendfile_getobj(td, fp, &obj, &vp, &shmfd, &obj_size, &bsize);
707 	if (error != 0)
708 		return (error);
709 
710 	error = sendfile_getsock(td, sockfd, &sock_fp, &so);
711 	if (error != 0)
712 		goto out;
713 
714 #ifdef MAC
715 	error = mac_socket_check_send(td->td_ucred, so);
716 	if (error != 0)
717 		goto out;
718 #endif
719 
720 	SFSTAT_INC(sf_syscalls);
721 	SFSTAT_ADD(sf_rhpages_requested, SF_READAHEAD(flags));
722 
723 	if (flags & SF_SYNC) {
724 		sfs = malloc(sizeof(*sfs), M_SENDFILE, M_WAITOK | M_ZERO);
725 		mtx_init(&sfs->mtx, "sendfile", NULL, MTX_DEF);
726 		cv_init(&sfs->cv, "sendfile");
727 		sfs->waiting = true;
728 	}
729 
730 	rem = nbytes ? omin(nbytes, obj_size - offset) : obj_size - offset;
731 
732 	/*
733 	 * Protect against multiple writers to the socket.
734 	 *
735 	 * XXXRW: Historically this has assumed non-interruptibility, so now
736 	 * we implement that, but possibly shouldn't.
737 	 */
738 	error = SOCK_IO_SEND_LOCK(so, SBL_WAIT | SBL_NOINTR);
739 	if (error != 0)
740 		goto out;
741 #ifdef KERN_TLS
742 	tls = ktls_hold(so->so_snd.sb_tls_info);
743 #endif
744 
745 	/*
746 	 * Loop through the pages of the file, starting with the requested
747 	 * offset. Get a file page (do I/O if necessary), map the file page
748 	 * into an sf_buf, attach an mbuf header to the sf_buf, and queue
749 	 * it on the socket.
750 	 * This is done in two loops.  The inner loop turns as many pages
751 	 * as it can, up to available socket buffer space, without blocking
752 	 * into mbufs to have it bulk delivered into the socket send buffer.
753 	 * The outer loop checks the state and available space of the socket
754 	 * and takes care of the overall progress.
755 	 */
756 	for (off = offset; rem > 0; ) {
757 		struct sf_io *sfio;
758 		vm_page_t *pa;
759 		struct mbuf *m0, *mtail;
760 		int nios, space, npages, rhpages;
761 
762 		mtail = NULL;
763 		/*
764 		 * Check the socket state for ongoing connection,
765 		 * no errors and space in socket buffer.
766 		 * If space is low allow for the remainder of the
767 		 * file to be processed if it fits the socket buffer.
768 		 * Otherwise block in waiting for sufficient space
769 		 * to proceed, or if the socket is nonblocking, return
770 		 * to userland with EAGAIN while reporting how far
771 		 * we've come.
772 		 * We wait until the socket buffer has significant free
773 		 * space to do bulk sends.  This makes good use of file
774 		 * system read ahead and allows packet segmentation
775 		 * offloading hardware to take over lots of work.  If
776 		 * we were not careful here we would send off only one
777 		 * sfbuf at a time.
778 		 */
779 		SOCKBUF_LOCK(&so->so_snd);
780 		if (so->so_snd.sb_lowat < so->so_snd.sb_hiwat / 2)
781 			so->so_snd.sb_lowat = so->so_snd.sb_hiwat / 2;
782 retry_space:
783 		if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
784 			error = EPIPE;
785 			SOCKBUF_UNLOCK(&so->so_snd);
786 			goto done;
787 		} else if (so->so_error) {
788 			error = so->so_error;
789 			so->so_error = 0;
790 			SOCKBUF_UNLOCK(&so->so_snd);
791 			goto done;
792 		}
793 		if ((so->so_state & SS_ISCONNECTED) == 0) {
794 			SOCKBUF_UNLOCK(&so->so_snd);
795 			error = ENOTCONN;
796 			goto done;
797 		}
798 
799 		space = sbspace(&so->so_snd);
800 		if (space < rem &&
801 		    (space <= 0 ||
802 		     space < so->so_snd.sb_lowat)) {
803 			if (so->so_state & SS_NBIO) {
804 				SOCKBUF_UNLOCK(&so->so_snd);
805 				error = EAGAIN;
806 				goto done;
807 			}
808 			/*
809 			 * sbwait drops the lock while sleeping.
810 			 * When we loop back to retry_space the
811 			 * state may have changed and we retest
812 			 * for it.
813 			 */
814 			error = sbwait(so, SO_SND);
815 			/*
816 			 * An error from sbwait usually indicates that we've
817 			 * been interrupted by a signal. If we've sent anything
818 			 * then return bytes sent, otherwise return the error.
819 			 */
820 			if (error != 0) {
821 				SOCKBUF_UNLOCK(&so->so_snd);
822 				goto done;
823 			}
824 			goto retry_space;
825 		}
826 		SOCKBUF_UNLOCK(&so->so_snd);
827 
828 		/*
829 		 * At the beginning of the first loop check if any headers
830 		 * are specified and copy them into mbufs.  Reduce space in
831 		 * the socket buffer by the size of the header mbuf chain.
832 		 * Clear hdr_uio here and hdrlen at the end of the first loop.
833 		 */
834 		if (hdr_uio != NULL && hdr_uio->uio_resid > 0) {
835 			hdr_uio->uio_td = td;
836 			hdr_uio->uio_rw = UIO_WRITE;
837 #ifdef KERN_TLS
838 			if (tls != NULL)
839 				mh = m_uiotombuf(hdr_uio, M_WAITOK, space,
840 				    tls->params.max_frame_len, M_EXTPG);
841 			else
842 #endif
843 				mh = m_uiotombuf(hdr_uio, M_WAITOK,
844 				    space, 0, 0);
845 			hdrlen = m_length(mh, &mhtail);
846 			space -= hdrlen;
847 			/*
848 			 * If header consumed all the socket buffer space,
849 			 * don't waste CPU cycles and jump to the end.
850 			 */
851 			if (space == 0) {
852 				sfio = NULL;
853 				nios = 0;
854 				goto prepend_header;
855 			}
856 			hdr_uio = NULL;
857 		}
858 
859 		if (vp != NULL) {
860 			error = vn_lock(vp, LK_SHARED);
861 			if (error != 0)
862 				goto done;
863 
864 			/*
865 			 * Check to see if the file size has changed.
866 			 */
867 			if (obj->type == OBJT_VNODE) {
868 				VM_OBJECT_RLOCK(obj);
869 				nobj_size = obj->un_pager.vnp.vnp_size;
870 				VM_OBJECT_RUNLOCK(obj);
871 			} else {
872 				error = VOP_GETATTR(vp, &va, td->td_ucred);
873 				if (error != 0) {
874 					VOP_UNLOCK(vp);
875 					goto done;
876 				}
877 				nobj_size = va.va_size;
878 			}
879 			if (off >= nobj_size) {
880 				VOP_UNLOCK(vp);
881 				goto done;
882 			}
883 			if (nobj_size != obj_size) {
884 				obj_size = nobj_size;
885 				rem = nbytes ? omin(nbytes + offset, obj_size) :
886 				    obj_size;
887 				rem -= off;
888 			}
889 		}
890 
891 		if (space > rem)
892 			space = rem;
893 		else if (space > PAGE_SIZE) {
894 			/*
895 			 * Use page boundaries when possible for large
896 			 * requests.
897 			 */
898 			if (off & PAGE_MASK)
899 				space -= (PAGE_SIZE - (off & PAGE_MASK));
900 			space = trunc_page(space);
901 			if (off & PAGE_MASK)
902 				space += (PAGE_SIZE - (off & PAGE_MASK));
903 		}
904 
905 		npages = howmany(space + (off & PAGE_MASK), PAGE_SIZE);
906 
907 		/*
908 		 * Calculate maximum allowed number of pages for readahead
909 		 * at this iteration.  If SF_USER_READAHEAD was set, we don't
910 		 * do any heuristics and use exactly the value supplied by
911 		 * application.  Otherwise, we allow readahead up to "rem".
912 		 * If application wants more, let it be, but there is no
913 		 * reason to go above maxphys.  Also check against "obj_size",
914 		 * since vm_pager_has_page() can hint beyond EOF.
915 		 */
916 		if (flags & SF_USER_READAHEAD) {
917 			rhpages = SF_READAHEAD(flags);
918 		} else {
919 			rhpages = howmany(rem + (off & PAGE_MASK), PAGE_SIZE) -
920 			    npages;
921 			rhpages += SF_READAHEAD(flags);
922 		}
923 		rhpages = min(howmany(maxphys, PAGE_SIZE), rhpages);
924 		rhpages = min(howmany(obj_size - trunc_page(off), PAGE_SIZE) -
925 		    npages, rhpages);
926 
927 		sfio = malloc(sizeof(struct sf_io) +
928 		    npages * sizeof(vm_page_t), M_SENDFILE, M_WAITOK);
929 		refcount_init(&sfio->nios, 1);
930 		sfio->obj = obj;
931 		sfio->error = 0;
932 		sfio->m = NULL;
933 		sfio->npages = npages;
934 #ifdef KERN_TLS
935 		/*
936 		 * This doesn't use ktls_hold() because sfio->m will
937 		 * also have a reference on 'tls' that will be valid
938 		 * for all of sfio's lifetime.
939 		 */
940 		sfio->tls = tls;
941 #endif
942 		vm_object_pip_add(obj, 1);
943 		error = sendfile_swapin(obj, sfio, &nios, off, space, rhpages,
944 		    flags);
945 		if (error != 0) {
946 			if (vp != NULL)
947 				VOP_UNLOCK(vp);
948 			sendfile_iodone(sfio, NULL, 0, error);
949 			goto done;
950 		}
951 
952 		/*
953 		 * Loop and construct maximum sized mbuf chain to be bulk
954 		 * dumped into socket buffer.
955 		 */
956 		pa = sfio->pa;
957 
958 		/*
959 		 * Use unmapped mbufs if enabled for TCP.  Unmapped
960 		 * bufs are restricted to TCP as that is what has been
961 		 * tested.  In particular, unmapped mbufs have not
962 		 * been tested with UNIX-domain sockets.
963 		 *
964 		 * TLS frames always require unmapped mbufs.
965 		 */
966 		if ((mb_use_ext_pgs &&
967 		    so->so_proto->pr_protocol == IPPROTO_TCP)
968 #ifdef KERN_TLS
969 		    || tls != NULL
970 #endif
971 		    ) {
972 			use_ext_pgs = true;
973 #ifdef KERN_TLS
974 			if (tls != NULL)
975 				max_pgs = num_pages(tls->params.max_frame_len);
976 			else
977 #endif
978 				max_pgs = MBUF_PEXT_MAX_PGS;
979 
980 			/* Start at last index, to wrap on first use. */
981 			ext_pgs_idx = max_pgs - 1;
982 		}
983 
984 		for (int i = 0; i < npages; i++) {
985 			/*
986 			 * If a page wasn't grabbed successfully, then
987 			 * trim the array. Can happen only with SF_NODISKIO.
988 			 */
989 			if (pa[i] == NULL) {
990 				SFSTAT_INC(sf_busy);
991 				fixspace(npages, i, off, &space);
992 				sfio->npages = i;
993 				softerr = EBUSY;
994 				break;
995 			}
996 			pga = pa[i];
997 			if (pga == bogus_page)
998 				pga = vm_page_relookup(obj, sfio->pindex0 + i);
999 
1000 			if (use_ext_pgs) {
1001 				off_t xfs;
1002 
1003 				ext_pgs_idx++;
1004 				if (ext_pgs_idx == max_pgs) {
1005 					m0 = mb_alloc_ext_pgs(M_WAITOK,
1006 					    sendfile_free_mext_pg, M_RDONLY);
1007 
1008 					if (flags & SF_NOCACHE) {
1009 						m0->m_ext.ext_flags |=
1010 						    EXT_FLAG_NOCACHE;
1011 
1012 						/*
1013 						 * See comment below regarding
1014 						 * ignoring SF_NOCACHE for the
1015 						 * last page.
1016 						 */
1017 						if ((npages - i <= max_pgs) &&
1018 						    ((off + space) & PAGE_MASK) &&
1019 						    (rem > space || rhpages > 0))
1020 							m0->m_ext.ext_flags |=
1021 							    EXT_FLAG_CACHE_LAST;
1022 					}
1023 					if (sfs != NULL) {
1024 						m0->m_ext.ext_flags |=
1025 						    EXT_FLAG_SYNC;
1026 						m0->m_ext.ext_arg1 = sfs;
1027 						mtx_lock(&sfs->mtx);
1028 						sfs->count++;
1029 						mtx_unlock(&sfs->mtx);
1030 					}
1031 					ext_pgs_idx = 0;
1032 
1033 					/* Append to mbuf chain. */
1034 					if (mtail != NULL)
1035 						mtail->m_next = m0;
1036 					else
1037 						m = m0;
1038 					mtail = m0;
1039 					m0->m_epg_1st_off =
1040 					    vmoff(i, off) & PAGE_MASK;
1041 				}
1042 				if (nios) {
1043 					mtail->m_flags |= M_NOTREADY;
1044 					m0->m_epg_nrdy++;
1045 				}
1046 
1047 				m0->m_epg_pa[ext_pgs_idx] = VM_PAGE_TO_PHYS(pga);
1048 				m0->m_epg_npgs++;
1049 				xfs = xfsize(i, npages, off, space);
1050 				m0->m_epg_last_len = xfs;
1051 				MBUF_EXT_PGS_ASSERT_SANITY(m0);
1052 				mtail->m_len += xfs;
1053 				mtail->m_ext.ext_size += PAGE_SIZE;
1054 				continue;
1055 			}
1056 
1057 			/*
1058 			 * Get a sendfile buf.  When allocating the
1059 			 * first buffer for mbuf chain, we usually
1060 			 * wait as long as necessary, but this wait
1061 			 * can be interrupted.  For consequent
1062 			 * buffers, do not sleep, since several
1063 			 * threads might exhaust the buffers and then
1064 			 * deadlock.
1065 			 */
1066 			sf = sf_buf_alloc(pga,
1067 			    m != NULL ? SFB_NOWAIT : SFB_CATCH);
1068 			if (sf == NULL) {
1069 				SFSTAT_INC(sf_allocfail);
1070 				sendfile_iowait(sfio, "sfnosf");
1071 				for (int j = i; j < npages; j++) {
1072 					vm_page_unwire(pa[j], PQ_INACTIVE);
1073 					pa[j] = NULL;
1074 				}
1075 				if (m == NULL)
1076 					softerr = ENOBUFS;
1077 				fixspace(npages, i, off, &space);
1078 				sfio->npages = i;
1079 				break;
1080 			}
1081 
1082 			m0 = m_get(M_WAITOK, MT_DATA);
1083 			m0->m_ext.ext_buf = (char *)sf_buf_kva(sf);
1084 			m0->m_ext.ext_size = PAGE_SIZE;
1085 			m0->m_ext.ext_arg1 = sf;
1086 			m0->m_ext.ext_type = EXT_SFBUF;
1087 			m0->m_ext.ext_flags = EXT_FLAG_EMBREF;
1088 			m0->m_ext.ext_free = sendfile_free_mext;
1089 			/*
1090 			 * SF_NOCACHE sets the page as being freed upon send.
1091 			 * However, we ignore it for the last page in 'space',
1092 			 * if the page is truncated, and we got more data to
1093 			 * send (rem > space), or if we have readahead
1094 			 * configured (rhpages > 0).
1095 			 */
1096 			if ((flags & SF_NOCACHE) &&
1097 			    (i != npages - 1 ||
1098 			    !((off + space) & PAGE_MASK) ||
1099 			    !(rem > space || rhpages > 0)))
1100 				m0->m_ext.ext_flags |= EXT_FLAG_NOCACHE;
1101 			if (sfs != NULL) {
1102 				m0->m_ext.ext_flags |= EXT_FLAG_SYNC;
1103 				m0->m_ext.ext_arg2 = sfs;
1104 				mtx_lock(&sfs->mtx);
1105 				sfs->count++;
1106 				mtx_unlock(&sfs->mtx);
1107 			}
1108 			m0->m_ext.ext_count = 1;
1109 			m0->m_flags |= (M_EXT | M_RDONLY);
1110 			if (nios)
1111 				m0->m_flags |= M_NOTREADY;
1112 			m0->m_data = (char *)sf_buf_kva(sf) +
1113 			    (vmoff(i, off) & PAGE_MASK);
1114 			m0->m_len = xfsize(i, npages, off, space);
1115 
1116 			/* Append to mbuf chain. */
1117 			if (mtail != NULL)
1118 				mtail->m_next = m0;
1119 			else
1120 				m = m0;
1121 			mtail = m0;
1122 		}
1123 
1124 		if (vp != NULL)
1125 			VOP_UNLOCK(vp);
1126 
1127 		/* Keep track of bytes processed. */
1128 		off += space;
1129 		rem -= space;
1130 
1131 		/*
1132 		 * Prepend header, if any.  Save pointer to first mbuf
1133 		 * with a page.
1134 		 */
1135 		if (hdrlen) {
1136 prepend_header:
1137 			m0 = mhtail->m_next = m;
1138 			m = mh;
1139 			mh = NULL;
1140 		} else
1141 			m0 = m;
1142 
1143 		if (m == NULL) {
1144 			KASSERT(softerr, ("%s: m NULL, no error", __func__));
1145 			error = softerr;
1146 			sendfile_iodone(sfio, NULL, 0, 0);
1147 			goto done;
1148 		}
1149 
1150 		/* Add the buffer chain to the socket buffer. */
1151 		KASSERT(m_length(m, NULL) == space + hdrlen,
1152 		    ("%s: mlen %u space %d hdrlen %d",
1153 		    __func__, m_length(m, NULL), space, hdrlen));
1154 
1155 		CURVNET_SET(so->so_vnet);
1156 #ifdef KERN_TLS
1157 		if (tls != NULL)
1158 			ktls_frame(m, tls, &tls_enq_cnt, TLS_RLTYPE_APP);
1159 #endif
1160 		if (nios == 0) {
1161 			/*
1162 			 * If sendfile_swapin() didn't initiate any I/Os,
1163 			 * which happens if all data is cached in VM, or if
1164 			 * the header consumed all socket buffer space and
1165 			 * sfio is NULL, then we can send data right now
1166 			 * without the PRUS_NOTREADY flag.
1167 			 */
1168 			if (sfio != NULL)
1169 				sendfile_iodone(sfio, NULL, 0, 0);
1170 #ifdef KERN_TLS
1171 			if (tls != NULL && tls->mode == TCP_TLS_MODE_SW) {
1172 				error = so->so_proto->pr_send(so,
1173 				    PRUS_NOTREADY, m, NULL, NULL, td);
1174 				if (error != 0) {
1175 					m_freem(m);
1176 				} else {
1177 					soref(so);
1178 					ktls_enqueue(m, so, tls_enq_cnt);
1179 				}
1180 			} else
1181 #endif
1182 				error = so->so_proto->pr_send(so, 0, m, NULL,
1183 				    NULL, td);
1184 		} else {
1185 			sfio->so = so;
1186 			sfio->m = m0;
1187 			soref(so);
1188 			error = so->so_proto->pr_send(so, PRUS_NOTREADY, m,
1189 			    NULL, NULL, td);
1190 			sendfile_iodone(sfio, NULL, 0, error);
1191 		}
1192 #ifdef TCP_REQUEST_TRK
1193 		if (so->so_proto->pr_protocol == IPPROTO_TCP) {
1194 			/* log the sendfile call to the TCP log, if enabled */
1195 			tcp_log_sendfile(so, offset, nbytes, flags);
1196 		}
1197 #endif
1198 		CURVNET_RESTORE();
1199 
1200 		m = NULL;
1201 		if (error)
1202 			goto done;
1203 		sbytes += space + hdrlen;
1204 		if (hdrlen)
1205 			hdrlen = 0;
1206 		if (softerr) {
1207 			error = softerr;
1208 			goto done;
1209 		}
1210 	}
1211 
1212 	/*
1213 	 * Send trailers. Wimp out and use writev(2).
1214 	 */
1215 	if (trl_uio != NULL) {
1216 		SOCK_IO_SEND_UNLOCK(so);
1217 		error = kern_writev(td, sockfd, trl_uio);
1218 		if (error == 0)
1219 			sbytes += td->td_retval[0];
1220 		goto out;
1221 	}
1222 
1223 done:
1224 	SOCK_IO_SEND_UNLOCK(so);
1225 out:
1226 	/*
1227 	 * If there was no error we have to clear td->td_retval[0]
1228 	 * because it may have been set by writev.
1229 	 */
1230 	if (error == 0) {
1231 		td->td_retval[0] = 0;
1232 	}
1233 	if (sent != NULL) {
1234 		(*sent) = sbytes;
1235 	}
1236 	if (obj != NULL)
1237 		vm_object_deallocate(obj);
1238 	if (so)
1239 		fdrop(sock_fp, td);
1240 	if (m)
1241 		m_freem(m);
1242 	if (mh)
1243 		m_freem(mh);
1244 
1245 	if (sfs != NULL) {
1246 		mtx_lock(&sfs->mtx);
1247 		if (sfs->count != 0)
1248 			error = cv_wait_sig(&sfs->cv, &sfs->mtx);
1249 		if (sfs->count == 0) {
1250 			sendfile_sync_destroy(sfs);
1251 		} else {
1252 			sfs->waiting = false;
1253 			mtx_unlock(&sfs->mtx);
1254 		}
1255 	}
1256 #ifdef KERN_TLS
1257 	if (tls != NULL)
1258 		ktls_free(tls);
1259 #endif
1260 
1261 	if (error == ERESTART)
1262 		error = EINTR;
1263 
1264 	return (error);
1265 }
1266 
1267 static int
sendfile(struct thread * td,struct sendfile_args * uap,int compat)1268 sendfile(struct thread *td, struct sendfile_args *uap, int compat)
1269 {
1270 	struct sf_hdtr hdtr;
1271 	struct uio *hdr_uio, *trl_uio;
1272 	struct file *fp;
1273 	off_t sbytes;
1274 	int error;
1275 
1276 	/*
1277 	 * File offset must be positive.  If it goes beyond EOF
1278 	 * we send only the header/trailer and no payload data.
1279 	 */
1280 	if (uap->offset < 0)
1281 		return (EINVAL);
1282 
1283 	sbytes = 0;
1284 	hdr_uio = trl_uio = NULL;
1285 
1286 	if (uap->hdtr != NULL) {
1287 		error = copyin(uap->hdtr, &hdtr, sizeof(hdtr));
1288 		if (error != 0)
1289 			goto out;
1290 		if (hdtr.headers != NULL) {
1291 			error = copyinuio(hdtr.headers, hdtr.hdr_cnt,
1292 			    &hdr_uio);
1293 			if (error != 0)
1294 				goto out;
1295 #ifdef COMPAT_FREEBSD4
1296 			/*
1297 			 * In FreeBSD < 5.0 the nbytes to send also included
1298 			 * the header.  If compat is specified subtract the
1299 			 * header size from nbytes.
1300 			 */
1301 			if (compat) {
1302 				if (uap->nbytes > hdr_uio->uio_resid)
1303 					uap->nbytes -= hdr_uio->uio_resid;
1304 				else
1305 					uap->nbytes = 0;
1306 			}
1307 #endif
1308 		}
1309 		if (hdtr.trailers != NULL) {
1310 			error = copyinuio(hdtr.trailers, hdtr.trl_cnt,
1311 			    &trl_uio);
1312 			if (error != 0)
1313 				goto out;
1314 		}
1315 	}
1316 
1317 	AUDIT_ARG_FD(uap->fd);
1318 
1319 	/*
1320 	 * sendfile(2) can start at any offset within a file so we require
1321 	 * CAP_READ+CAP_SEEK = CAP_PREAD.
1322 	 */
1323 	if ((error = fget_read(td, uap->fd, &cap_pread_rights, &fp)) != 0)
1324 		goto out;
1325 
1326 	error = fo_sendfile(fp, uap->s, hdr_uio, trl_uio, uap->offset,
1327 	    uap->nbytes, &sbytes, uap->flags, td);
1328 	fdrop(fp, td);
1329 
1330 	if (uap->sbytes != NULL)
1331 		(void)copyout(&sbytes, uap->sbytes, sizeof(off_t));
1332 
1333 out:
1334 	freeuio(hdr_uio);
1335 	freeuio(trl_uio);
1336 	return (error);
1337 }
1338 
1339 /*
1340  * sendfile(2)
1341  *
1342  * int sendfile(int fd, int s, off_t offset, size_t nbytes,
1343  *       struct sf_hdtr *hdtr, off_t *sbytes, int flags)
1344  *
1345  * Send a file specified by 'fd' and starting at 'offset' to a socket
1346  * specified by 's'. Send only 'nbytes' of the file or until EOF if nbytes ==
1347  * 0.  Optionally add a header and/or trailer to the socket output.  If
1348  * specified, write the total number of bytes sent into *sbytes.
1349  */
1350 int
sys_sendfile(struct thread * td,struct sendfile_args * uap)1351 sys_sendfile(struct thread *td, struct sendfile_args *uap)
1352 {
1353 
1354 	return (sendfile(td, uap, 0));
1355 }
1356 
1357 #ifdef COMPAT_FREEBSD4
1358 int
freebsd4_sendfile(struct thread * td,struct freebsd4_sendfile_args * uap)1359 freebsd4_sendfile(struct thread *td, struct freebsd4_sendfile_args *uap)
1360 {
1361 	struct sendfile_args args;
1362 
1363 	args.fd = uap->fd;
1364 	args.s = uap->s;
1365 	args.offset = uap->offset;
1366 	args.nbytes = uap->nbytes;
1367 	args.hdtr = uap->hdtr;
1368 	args.sbytes = uap->sbytes;
1369 	args.flags = uap->flags;
1370 
1371 	return (sendfile(td, &args, 1));
1372 }
1373 #endif /* COMPAT_FREEBSD4 */
1374