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_compat.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/mutex.h> 41 #include <sys/sysproto.h> 42 #include <sys/malloc.h> 43 #include <sys/proc.h> 44 #include <sys/mman.h> 45 #include <sys/mount.h> 46 #include <sys/mbuf.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/vnode.h> 55 56 #include <net/vnet.h> 57 58 #include <security/audit/audit.h> 59 #include <security/mac/mac_framework.h> 60 61 #include <vm/vm.h> 62 #include <vm/vm_object.h> 63 #include <vm/vm_pager.h> 64 65 #define EXT_FLAG_SYNC EXT_FLAG_VENDOR1 66 #define EXT_FLAG_NOCACHE EXT_FLAG_VENDOR2 67 68 /* 69 * Structure describing a single sendfile(2) I/O, which may consist of 70 * several underlying pager I/Os. 71 * 72 * The syscall context allocates the structure and initializes 'nios' 73 * to 1. As sendfile_swapin() runs through pages and starts asynchronous 74 * paging operations, it increments 'nios'. 75 * 76 * Every I/O completion calls sendfile_iodone(), which decrements the 'nios', 77 * and the syscall also calls sendfile_iodone() after allocating all mbufs, 78 * linking them and sending to socket. Whoever reaches zero 'nios' is 79 * responsible to * call pru_ready on the socket, to notify it of readyness 80 * of the data. 81 */ 82 struct sf_io { 83 volatile u_int nios; 84 u_int error; 85 int npages; 86 struct socket *so; 87 struct mbuf *m; 88 vm_page_t pa[]; 89 }; 90 91 /* 92 * Structure used to track requests with SF_SYNC flag. 93 */ 94 struct sendfile_sync { 95 struct mtx mtx; 96 struct cv cv; 97 unsigned count; 98 }; 99 100 counter_u64_t sfstat[sizeof(struct sfstat) / sizeof(uint64_t)]; 101 102 static void 103 sfstat_init(const void *unused) 104 { 105 106 COUNTER_ARRAY_ALLOC(sfstat, sizeof(struct sfstat) / sizeof(uint64_t), 107 M_WAITOK); 108 } 109 SYSINIT(sfstat, SI_SUB_MBUF, SI_ORDER_FIRST, sfstat_init, NULL); 110 111 static int 112 sfstat_sysctl(SYSCTL_HANDLER_ARGS) 113 { 114 struct sfstat s; 115 116 COUNTER_ARRAY_COPY(sfstat, &s, sizeof(s) / sizeof(uint64_t)); 117 if (req->newptr) 118 COUNTER_ARRAY_ZERO(sfstat, sizeof(s) / sizeof(uint64_t)); 119 return (SYSCTL_OUT(req, &s, sizeof(s))); 120 } 121 SYSCTL_PROC(_kern_ipc, OID_AUTO, sfstat, CTLTYPE_OPAQUE | CTLFLAG_RW, 122 NULL, 0, sfstat_sysctl, "I", "sendfile statistics"); 123 124 /* 125 * Detach mapped page and release resources back to the system. Called 126 * by mbuf(9) code when last reference to a page is freed. 127 */ 128 static void 129 sendfile_free_page(vm_page_t pg, bool nocache) 130 { 131 bool freed; 132 133 vm_page_lock(pg); 134 /* 135 * In either case check for the object going away on us. This can 136 * happen since we don't hold a reference to it. If so, we're 137 * responsible for freeing the page. In 'noncache' case try to free 138 * the page, but only if it is cheap to. 139 */ 140 if (vm_page_unwire_noq(pg)) { 141 vm_object_t obj; 142 143 if ((obj = pg->object) == NULL) 144 vm_page_free(pg); 145 else { 146 freed = false; 147 if (nocache && !vm_page_xbusied(pg) && 148 VM_OBJECT_TRYWLOCK(obj)) { 149 /* Only free unmapped pages. */ 150 if (obj->ref_count == 0 || 151 !pmap_page_is_mapped(pg)) 152 /* 153 * The busy test before the object is 154 * locked cannot be relied upon. 155 */ 156 freed = vm_page_try_to_free(pg); 157 VM_OBJECT_WUNLOCK(obj); 158 } 159 if (!freed) { 160 /* 161 * If we were asked to not cache the page, place 162 * it near the head of the inactive queue so 163 * that it is reclaimed sooner. Otherwise, 164 * maintain LRU. 165 */ 166 if (nocache) 167 vm_page_deactivate_noreuse(pg); 168 else if (pg->queue == PQ_ACTIVE) 169 vm_page_reference(pg); 170 else 171 vm_page_deactivate(pg); 172 } 173 } 174 } 175 vm_page_unlock(pg); 176 } 177 178 static void 179 sendfile_free_mext(struct mbuf *m) 180 { 181 struct sf_buf *sf; 182 vm_page_t pg; 183 bool nocache; 184 185 KASSERT(m->m_flags & M_EXT && m->m_ext.ext_type == EXT_SFBUF, 186 ("%s: m %p !M_EXT or !EXT_SFBUF", __func__, m)); 187 188 sf = m->m_ext.ext_arg1; 189 pg = sf_buf_page(sf); 190 nocache = m->m_ext.ext_flags & EXT_FLAG_NOCACHE; 191 192 sf_buf_free(sf); 193 sendfile_free_page(pg, nocache); 194 195 if (m->m_ext.ext_flags & EXT_FLAG_SYNC) { 196 struct sendfile_sync *sfs = m->m_ext.ext_arg2; 197 198 mtx_lock(&sfs->mtx); 199 KASSERT(sfs->count > 0, ("Sendfile sync botchup count == 0")); 200 if (--sfs->count == 0) 201 cv_signal(&sfs->cv); 202 mtx_unlock(&sfs->mtx); 203 } 204 } 205 206 /* 207 * Helper function to calculate how much data to put into page i of n. 208 * Only first and last pages are special. 209 */ 210 static inline off_t 211 xfsize(int i, int n, off_t off, off_t len) 212 { 213 214 if (i == 0) 215 return (omin(PAGE_SIZE - (off & PAGE_MASK), len)); 216 217 if (i == n - 1 && ((off + len) & PAGE_MASK) > 0) 218 return ((off + len) & PAGE_MASK); 219 220 return (PAGE_SIZE); 221 } 222 223 /* 224 * Helper function to get offset within object for i page. 225 */ 226 static inline vm_ooffset_t 227 vmoff(int i, off_t off) 228 { 229 230 if (i == 0) 231 return ((vm_ooffset_t)off); 232 233 return (trunc_page(off + i * PAGE_SIZE)); 234 } 235 236 /* 237 * Helper function used when allocation of a page or sf_buf failed. 238 * Pretend as if we don't have enough space, subtract xfsize() of 239 * all pages that failed. 240 */ 241 static inline void 242 fixspace(int old, int new, off_t off, int *space) 243 { 244 245 KASSERT(old > new, ("%s: old %d new %d", __func__, old, new)); 246 247 /* Subtract last one. */ 248 *space -= xfsize(old - 1, old, off, *space); 249 old--; 250 251 if (new == old) 252 /* There was only one page. */ 253 return; 254 255 /* Subtract first one. */ 256 if (new == 0) { 257 *space -= xfsize(0, old, off, *space); 258 new++; 259 } 260 261 /* Rest of pages are full sized. */ 262 *space -= (old - new) * PAGE_SIZE; 263 264 KASSERT(*space >= 0, ("%s: space went backwards", __func__)); 265 } 266 267 /* 268 * I/O completion callback. 269 */ 270 static void 271 sendfile_iodone(void *arg, vm_page_t *pg, int count, int error) 272 { 273 struct sf_io *sfio = arg; 274 struct socket *so = sfio->so; 275 276 for (int i = 0; i < count; i++) 277 if (pg[i] != bogus_page) 278 vm_page_xunbusy(pg[i]); 279 280 if (error) 281 sfio->error = error; 282 283 if (!refcount_release(&sfio->nios)) 284 return; 285 286 CURVNET_SET(so->so_vnet); 287 if (sfio->error) { 288 struct mbuf *m; 289 290 /* 291 * I/O operation failed. The state of data in the socket 292 * is now inconsistent, and all what we can do is to tear 293 * it down. Protocol abort method would tear down protocol 294 * state, free all ready mbufs and detach not ready ones. 295 * We will free the mbufs corresponding to this I/O manually. 296 * 297 * The socket would be marked with EIO and made available 298 * for read, so that application receives EIO on next 299 * syscall and eventually closes the socket. 300 */ 301 so->so_proto->pr_usrreqs->pru_abort(so); 302 so->so_error = EIO; 303 304 m = sfio->m; 305 for (int i = 0; i < sfio->npages; i++) 306 m = m_free(m); 307 } else 308 (void )(so->so_proto->pr_usrreqs->pru_ready)(so, sfio->m, 309 sfio->npages); 310 311 SOCK_LOCK(so); 312 sorele(so); 313 CURVNET_RESTORE(); 314 free(sfio, M_TEMP); 315 } 316 317 /* 318 * Iterate through pages vector and request paging for non-valid pages. 319 */ 320 static int 321 sendfile_swapin(vm_object_t obj, struct sf_io *sfio, off_t off, off_t len, 322 int npages, int rhpages, int flags) 323 { 324 vm_page_t *pa = sfio->pa; 325 int grabbed, nios; 326 327 nios = 0; 328 flags = (flags & SF_NODISKIO) ? VM_ALLOC_NOWAIT : 0; 329 330 /* 331 * First grab all the pages and wire them. Note that we grab 332 * only required pages. Readahead pages are dealt with later. 333 */ 334 VM_OBJECT_WLOCK(obj); 335 336 grabbed = vm_page_grab_pages(obj, OFF_TO_IDX(off), 337 VM_ALLOC_NORMAL | VM_ALLOC_WIRED | flags, pa, npages); 338 if (grabbed < npages) { 339 for (int i = grabbed; i < npages; i++) 340 pa[i] = NULL; 341 npages = grabbed; 342 rhpages = 0; 343 } 344 345 for (int i = 0; i < npages;) { 346 int j, a, count, rv; 347 348 /* Skip valid pages. */ 349 if (vm_page_is_valid(pa[i], vmoff(i, off) & PAGE_MASK, 350 xfsize(i, npages, off, len))) { 351 vm_page_xunbusy(pa[i]); 352 SFSTAT_INC(sf_pages_valid); 353 i++; 354 continue; 355 } 356 357 /* 358 * Next page is invalid. Check if it belongs to pager. It 359 * may not be there, which is a regular situation for shmem 360 * pager. For vnode pager this happens only in case of 361 * a sparse file. 362 * 363 * Important feature of vm_pager_has_page() is the hint 364 * stored in 'a', about how many pages we can pagein after 365 * this page in a single I/O. 366 */ 367 if (!vm_pager_has_page(obj, OFF_TO_IDX(vmoff(i, off)), NULL, 368 &a)) { 369 pmap_zero_page(pa[i]); 370 pa[i]->valid = VM_PAGE_BITS_ALL; 371 MPASS(pa[i]->dirty == 0); 372 vm_page_xunbusy(pa[i]); 373 i++; 374 continue; 375 } 376 377 /* 378 * We want to pagein as many pages as possible, limited only 379 * by the 'a' hint and actual request. 380 */ 381 count = min(a + 1, npages - i); 382 383 /* 384 * We should not pagein into a valid page, thus we first trim 385 * any valid pages off the end of request, and substitute 386 * to bogus_page those, that are in the middle. 387 */ 388 for (j = i + count - 1; j > i; j--) { 389 if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK, 390 xfsize(j, npages, off, len))) { 391 count--; 392 rhpages = 0; 393 } else 394 break; 395 } 396 for (j = i + 1; j < i + count - 1; j++) 397 if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK, 398 xfsize(j, npages, off, len))) { 399 vm_page_xunbusy(pa[j]); 400 SFSTAT_INC(sf_pages_valid); 401 SFSTAT_INC(sf_pages_bogus); 402 pa[j] = bogus_page; 403 } 404 405 refcount_acquire(&sfio->nios); 406 rv = vm_pager_get_pages_async(obj, pa + i, count, NULL, 407 i + count == npages ? &rhpages : NULL, 408 &sendfile_iodone, sfio); 409 KASSERT(rv == VM_PAGER_OK, ("%s: pager fail obj %p page %p", 410 __func__, obj, pa[i])); 411 412 SFSTAT_INC(sf_iocnt); 413 SFSTAT_ADD(sf_pages_read, count); 414 if (i + count == npages) 415 SFSTAT_ADD(sf_rhpages_read, rhpages); 416 417 /* 418 * Restore the valid page pointers. They are already 419 * unbusied, but still wired. 420 */ 421 for (j = i; j < i + count; j++) 422 if (pa[j] == bogus_page) { 423 pa[j] = vm_page_lookup(obj, 424 OFF_TO_IDX(vmoff(j, off))); 425 KASSERT(pa[j], ("%s: page %p[%d] disappeared", 426 __func__, pa, j)); 427 428 } 429 i += count; 430 nios++; 431 } 432 433 VM_OBJECT_WUNLOCK(obj); 434 435 if (nios == 0 && npages != 0) 436 SFSTAT_INC(sf_noiocnt); 437 438 return (nios); 439 } 440 441 static int 442 sendfile_getobj(struct thread *td, struct file *fp, vm_object_t *obj_res, 443 struct vnode **vp_res, struct shmfd **shmfd_res, off_t *obj_size, 444 int *bsize) 445 { 446 struct vattr va; 447 vm_object_t obj; 448 struct vnode *vp; 449 struct shmfd *shmfd; 450 int error; 451 452 vp = *vp_res = NULL; 453 obj = NULL; 454 shmfd = *shmfd_res = NULL; 455 *bsize = 0; 456 457 /* 458 * The file descriptor must be a regular file and have a 459 * backing VM object. 460 */ 461 if (fp->f_type == DTYPE_VNODE) { 462 vp = fp->f_vnode; 463 vn_lock(vp, LK_SHARED | LK_RETRY); 464 if (vp->v_type != VREG) { 465 error = EINVAL; 466 goto out; 467 } 468 *bsize = vp->v_mount->mnt_stat.f_iosize; 469 error = VOP_GETATTR(vp, &va, td->td_ucred); 470 if (error != 0) 471 goto out; 472 *obj_size = va.va_size; 473 obj = vp->v_object; 474 if (obj == NULL) { 475 error = EINVAL; 476 goto out; 477 } 478 } else if (fp->f_type == DTYPE_SHM) { 479 error = 0; 480 shmfd = fp->f_data; 481 obj = shmfd->shm_object; 482 *obj_size = shmfd->shm_size; 483 } else { 484 error = EINVAL; 485 goto out; 486 } 487 488 VM_OBJECT_WLOCK(obj); 489 if ((obj->flags & OBJ_DEAD) != 0) { 490 VM_OBJECT_WUNLOCK(obj); 491 error = EBADF; 492 goto out; 493 } 494 495 /* 496 * Temporarily increase the backing VM object's reference 497 * count so that a forced reclamation of its vnode does not 498 * immediately destroy it. 499 */ 500 vm_object_reference_locked(obj); 501 VM_OBJECT_WUNLOCK(obj); 502 *obj_res = obj; 503 *vp_res = vp; 504 *shmfd_res = shmfd; 505 506 out: 507 if (vp != NULL) 508 VOP_UNLOCK(vp, 0); 509 return (error); 510 } 511 512 static int 513 sendfile_getsock(struct thread *td, int s, struct file **sock_fp, 514 struct socket **so) 515 { 516 cap_rights_t rights; 517 int error; 518 519 *sock_fp = NULL; 520 *so = NULL; 521 522 /* 523 * The socket must be a stream socket and connected. 524 */ 525 error = getsock_cap(td, s, cap_rights_init(&rights, CAP_SEND), 526 sock_fp, NULL, NULL); 527 if (error != 0) 528 return (error); 529 *so = (*sock_fp)->f_data; 530 if ((*so)->so_type != SOCK_STREAM) 531 return (EINVAL); 532 return (0); 533 } 534 535 int 536 vn_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio, 537 struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags, 538 struct thread *td) 539 { 540 struct file *sock_fp; 541 struct vnode *vp; 542 struct vm_object *obj; 543 struct socket *so; 544 struct mbuf *m, *mh, *mhtail; 545 struct sf_buf *sf; 546 struct shmfd *shmfd; 547 struct sendfile_sync *sfs; 548 struct vattr va; 549 off_t off, sbytes, rem, obj_size; 550 int error, softerr, bsize, hdrlen; 551 552 obj = NULL; 553 so = NULL; 554 m = mh = NULL; 555 sfs = NULL; 556 hdrlen = sbytes = 0; 557 softerr = 0; 558 559 error = sendfile_getobj(td, fp, &obj, &vp, &shmfd, &obj_size, &bsize); 560 if (error != 0) 561 return (error); 562 563 error = sendfile_getsock(td, sockfd, &sock_fp, &so); 564 if (error != 0) 565 goto out; 566 567 #ifdef MAC 568 error = mac_socket_check_send(td->td_ucred, so); 569 if (error != 0) 570 goto out; 571 #endif 572 573 SFSTAT_INC(sf_syscalls); 574 SFSTAT_ADD(sf_rhpages_requested, SF_READAHEAD(flags)); 575 576 if (flags & SF_SYNC) { 577 sfs = malloc(sizeof *sfs, M_TEMP, M_WAITOK | M_ZERO); 578 mtx_init(&sfs->mtx, "sendfile", NULL, MTX_DEF); 579 cv_init(&sfs->cv, "sendfile"); 580 } 581 582 rem = nbytes ? omin(nbytes, obj_size - offset) : obj_size - offset; 583 584 /* 585 * Protect against multiple writers to the socket. 586 * 587 * XXXRW: Historically this has assumed non-interruptibility, so now 588 * we implement that, but possibly shouldn't. 589 */ 590 (void)sblock(&so->so_snd, SBL_WAIT | SBL_NOINTR); 591 592 /* 593 * Loop through the pages of the file, starting with the requested 594 * offset. Get a file page (do I/O if necessary), map the file page 595 * into an sf_buf, attach an mbuf header to the sf_buf, and queue 596 * it on the socket. 597 * This is done in two loops. The inner loop turns as many pages 598 * as it can, up to available socket buffer space, without blocking 599 * into mbufs to have it bulk delivered into the socket send buffer. 600 * The outer loop checks the state and available space of the socket 601 * and takes care of the overall progress. 602 */ 603 for (off = offset; rem > 0; ) { 604 struct sf_io *sfio; 605 vm_page_t *pa; 606 struct mbuf *mtail; 607 int nios, space, npages, rhpages; 608 609 mtail = NULL; 610 /* 611 * Check the socket state for ongoing connection, 612 * no errors and space in socket buffer. 613 * If space is low allow for the remainder of the 614 * file to be processed if it fits the socket buffer. 615 * Otherwise block in waiting for sufficient space 616 * to proceed, or if the socket is nonblocking, return 617 * to userland with EAGAIN while reporting how far 618 * we've come. 619 * We wait until the socket buffer has significant free 620 * space to do bulk sends. This makes good use of file 621 * system read ahead and allows packet segmentation 622 * offloading hardware to take over lots of work. If 623 * we were not careful here we would send off only one 624 * sfbuf at a time. 625 */ 626 SOCKBUF_LOCK(&so->so_snd); 627 if (so->so_snd.sb_lowat < so->so_snd.sb_hiwat / 2) 628 so->so_snd.sb_lowat = so->so_snd.sb_hiwat / 2; 629 retry_space: 630 if (so->so_snd.sb_state & SBS_CANTSENDMORE) { 631 error = EPIPE; 632 SOCKBUF_UNLOCK(&so->so_snd); 633 goto done; 634 } else if (so->so_error) { 635 error = so->so_error; 636 so->so_error = 0; 637 SOCKBUF_UNLOCK(&so->so_snd); 638 goto done; 639 } 640 if ((so->so_state & SS_ISCONNECTED) == 0) { 641 SOCKBUF_UNLOCK(&so->so_snd); 642 error = ENOTCONN; 643 goto done; 644 } 645 646 space = sbspace(&so->so_snd); 647 if (space < rem && 648 (space <= 0 || 649 space < so->so_snd.sb_lowat)) { 650 if (so->so_state & SS_NBIO) { 651 SOCKBUF_UNLOCK(&so->so_snd); 652 error = EAGAIN; 653 goto done; 654 } 655 /* 656 * sbwait drops the lock while sleeping. 657 * When we loop back to retry_space the 658 * state may have changed and we retest 659 * for it. 660 */ 661 error = sbwait(&so->so_snd); 662 /* 663 * An error from sbwait usually indicates that we've 664 * been interrupted by a signal. If we've sent anything 665 * then return bytes sent, otherwise return the error. 666 */ 667 if (error != 0) { 668 SOCKBUF_UNLOCK(&so->so_snd); 669 goto done; 670 } 671 goto retry_space; 672 } 673 SOCKBUF_UNLOCK(&so->so_snd); 674 675 /* 676 * At the beginning of the first loop check if any headers 677 * are specified and copy them into mbufs. Reduce space in 678 * the socket buffer by the size of the header mbuf chain. 679 * Clear hdr_uio here and hdrlen at the end of the first loop. 680 */ 681 if (hdr_uio != NULL && hdr_uio->uio_resid > 0) { 682 hdr_uio->uio_td = td; 683 hdr_uio->uio_rw = UIO_WRITE; 684 mh = m_uiotombuf(hdr_uio, M_WAITOK, space, 0, 0); 685 hdrlen = m_length(mh, &mhtail); 686 space -= hdrlen; 687 /* 688 * If header consumed all the socket buffer space, 689 * don't waste CPU cycles and jump to the end. 690 */ 691 if (space == 0) { 692 sfio = NULL; 693 nios = 0; 694 goto prepend_header; 695 } 696 hdr_uio = NULL; 697 } 698 699 if (vp != NULL) { 700 error = vn_lock(vp, LK_SHARED); 701 if (error != 0) 702 goto done; 703 error = VOP_GETATTR(vp, &va, td->td_ucred); 704 if (error != 0 || off >= va.va_size) { 705 VOP_UNLOCK(vp, 0); 706 goto done; 707 } 708 if (va.va_size != obj_size) { 709 obj_size = va.va_size; 710 rem = nbytes ? 711 omin(nbytes + offset, obj_size) : obj_size; 712 rem -= off; 713 } 714 } 715 716 if (space > rem) 717 space = rem; 718 719 npages = howmany(space + (off & PAGE_MASK), PAGE_SIZE); 720 721 /* 722 * Calculate maximum allowed number of pages for readahead 723 * at this iteration. If SF_USER_READAHEAD was set, we don't 724 * do any heuristics and use exactly the value supplied by 725 * application. Otherwise, we allow readahead up to "rem". 726 * If application wants more, let it be, but there is no 727 * reason to go above MAXPHYS. Also check against "obj_size", 728 * since vm_pager_has_page() can hint beyond EOF. 729 */ 730 if (flags & SF_USER_READAHEAD) { 731 rhpages = SF_READAHEAD(flags); 732 } else { 733 rhpages = howmany(rem + (off & PAGE_MASK), PAGE_SIZE) - 734 npages; 735 rhpages += SF_READAHEAD(flags); 736 } 737 rhpages = min(howmany(MAXPHYS, PAGE_SIZE), rhpages); 738 rhpages = min(howmany(obj_size - trunc_page(off), PAGE_SIZE) - 739 npages, rhpages); 740 741 sfio = malloc(sizeof(struct sf_io) + 742 npages * sizeof(vm_page_t), M_TEMP, M_WAITOK); 743 refcount_init(&sfio->nios, 1); 744 sfio->so = so; 745 sfio->error = 0; 746 747 nios = sendfile_swapin(obj, sfio, off, space, npages, rhpages, 748 flags); 749 750 /* 751 * Loop and construct maximum sized mbuf chain to be bulk 752 * dumped into socket buffer. 753 */ 754 pa = sfio->pa; 755 for (int i = 0; i < npages; i++) { 756 struct mbuf *m0; 757 758 /* 759 * If a page wasn't grabbed successfully, then 760 * trim the array. Can happen only with SF_NODISKIO. 761 */ 762 if (pa[i] == NULL) { 763 SFSTAT_INC(sf_busy); 764 fixspace(npages, i, off, &space); 765 npages = i; 766 softerr = EBUSY; 767 break; 768 } 769 770 /* 771 * Get a sendfile buf. When allocating the 772 * first buffer for mbuf chain, we usually 773 * wait as long as necessary, but this wait 774 * can be interrupted. For consequent 775 * buffers, do not sleep, since several 776 * threads might exhaust the buffers and then 777 * deadlock. 778 */ 779 sf = sf_buf_alloc(pa[i], 780 m != NULL ? SFB_NOWAIT : SFB_CATCH); 781 if (sf == NULL) { 782 SFSTAT_INC(sf_allocfail); 783 for (int j = i; j < npages; j++) { 784 vm_page_lock(pa[j]); 785 vm_page_unwire(pa[j], PQ_INACTIVE); 786 vm_page_unlock(pa[j]); 787 } 788 if (m == NULL) 789 softerr = ENOBUFS; 790 fixspace(npages, i, off, &space); 791 npages = i; 792 break; 793 } 794 795 m0 = m_get(M_WAITOK, MT_DATA); 796 m0->m_ext.ext_buf = (char *)sf_buf_kva(sf); 797 m0->m_ext.ext_size = PAGE_SIZE; 798 m0->m_ext.ext_arg1 = sf; 799 m0->m_ext.ext_type = EXT_SFBUF; 800 m0->m_ext.ext_flags = EXT_FLAG_EMBREF; 801 m0->m_ext.ext_free = sendfile_free_mext; 802 /* 803 * SF_NOCACHE sets the page as being freed upon send. 804 * However, we ignore it for the last page in 'space', 805 * if the page is truncated, and we got more data to 806 * send (rem > space), or if we have readahead 807 * configured (rhpages > 0). 808 */ 809 if ((flags & SF_NOCACHE) && 810 (i != npages - 1 || 811 !((off + space) & PAGE_MASK) || 812 !(rem > space || rhpages > 0))) 813 m0->m_ext.ext_flags |= EXT_FLAG_NOCACHE; 814 if (sfs != NULL) { 815 m0->m_ext.ext_flags |= EXT_FLAG_SYNC; 816 m0->m_ext.ext_arg2 = sfs; 817 mtx_lock(&sfs->mtx); 818 sfs->count++; 819 mtx_unlock(&sfs->mtx); 820 } 821 m0->m_ext.ext_count = 1; 822 m0->m_flags |= (M_EXT | M_RDONLY); 823 if (nios) 824 m0->m_flags |= M_NOTREADY; 825 m0->m_data = (char *)sf_buf_kva(sf) + 826 (vmoff(i, off) & PAGE_MASK); 827 m0->m_len = xfsize(i, npages, off, space); 828 829 if (i == 0) 830 sfio->m = m0; 831 832 /* Append to mbuf chain. */ 833 if (mtail != NULL) 834 mtail->m_next = m0; 835 else 836 m = m0; 837 mtail = m0; 838 } 839 840 if (vp != NULL) 841 VOP_UNLOCK(vp, 0); 842 843 /* Keep track of bytes processed. */ 844 off += space; 845 rem -= space; 846 847 /* Prepend header, if any. */ 848 if (hdrlen) { 849 prepend_header: 850 mhtail->m_next = m; 851 m = mh; 852 mh = NULL; 853 } 854 855 if (m == NULL) { 856 KASSERT(softerr, ("%s: m NULL, no error", __func__)); 857 error = softerr; 858 free(sfio, M_TEMP); 859 goto done; 860 } 861 862 /* Add the buffer chain to the socket buffer. */ 863 KASSERT(m_length(m, NULL) == space + hdrlen, 864 ("%s: mlen %u space %d hdrlen %d", 865 __func__, m_length(m, NULL), space, hdrlen)); 866 867 CURVNET_SET(so->so_vnet); 868 if (nios == 0) { 869 /* 870 * If sendfile_swapin() didn't initiate any I/Os, 871 * which happens if all data is cached in VM, then 872 * we can send data right now without the 873 * PRUS_NOTREADY flag. 874 */ 875 free(sfio, M_TEMP); 876 error = (*so->so_proto->pr_usrreqs->pru_send) 877 (so, 0, m, NULL, NULL, td); 878 } else { 879 sfio->npages = npages; 880 soref(so); 881 error = (*so->so_proto->pr_usrreqs->pru_send) 882 (so, PRUS_NOTREADY, m, NULL, NULL, td); 883 sendfile_iodone(sfio, NULL, 0, 0); 884 } 885 CURVNET_RESTORE(); 886 887 m = NULL; /* pru_send always consumes */ 888 if (error) 889 goto done; 890 sbytes += space + hdrlen; 891 if (hdrlen) 892 hdrlen = 0; 893 if (softerr) { 894 error = softerr; 895 goto done; 896 } 897 } 898 899 /* 900 * Send trailers. Wimp out and use writev(2). 901 */ 902 if (trl_uio != NULL) { 903 sbunlock(&so->so_snd); 904 error = kern_writev(td, sockfd, trl_uio); 905 if (error == 0) 906 sbytes += td->td_retval[0]; 907 goto out; 908 } 909 910 done: 911 sbunlock(&so->so_snd); 912 out: 913 /* 914 * If there was no error we have to clear td->td_retval[0] 915 * because it may have been set by writev. 916 */ 917 if (error == 0) { 918 td->td_retval[0] = 0; 919 } 920 if (sent != NULL) { 921 (*sent) = sbytes; 922 } 923 if (obj != NULL) 924 vm_object_deallocate(obj); 925 if (so) 926 fdrop(sock_fp, td); 927 if (m) 928 m_freem(m); 929 if (mh) 930 m_freem(mh); 931 932 if (sfs != NULL) { 933 mtx_lock(&sfs->mtx); 934 if (sfs->count != 0) 935 cv_wait(&sfs->cv, &sfs->mtx); 936 KASSERT(sfs->count == 0, ("sendfile sync still busy")); 937 cv_destroy(&sfs->cv); 938 mtx_destroy(&sfs->mtx); 939 free(sfs, M_TEMP); 940 } 941 942 if (error == ERESTART) 943 error = EINTR; 944 945 return (error); 946 } 947 948 static int 949 sendfile(struct thread *td, struct sendfile_args *uap, int compat) 950 { 951 struct sf_hdtr hdtr; 952 struct uio *hdr_uio, *trl_uio; 953 struct file *fp; 954 cap_rights_t rights; 955 off_t sbytes; 956 int error; 957 958 /* 959 * File offset must be positive. If it goes beyond EOF 960 * we send only the header/trailer and no payload data. 961 */ 962 if (uap->offset < 0) 963 return (EINVAL); 964 965 sbytes = 0; 966 hdr_uio = trl_uio = NULL; 967 968 if (uap->hdtr != NULL) { 969 error = copyin(uap->hdtr, &hdtr, sizeof(hdtr)); 970 if (error != 0) 971 goto out; 972 if (hdtr.headers != NULL) { 973 error = copyinuio(hdtr.headers, hdtr.hdr_cnt, 974 &hdr_uio); 975 if (error != 0) 976 goto out; 977 #ifdef COMPAT_FREEBSD4 978 /* 979 * In FreeBSD < 5.0 the nbytes to send also included 980 * the header. If compat is specified subtract the 981 * header size from nbytes. 982 */ 983 if (compat) { 984 if (uap->nbytes > hdr_uio->uio_resid) 985 uap->nbytes -= hdr_uio->uio_resid; 986 else 987 uap->nbytes = 0; 988 } 989 #endif 990 } 991 if (hdtr.trailers != NULL) { 992 error = copyinuio(hdtr.trailers, hdtr.trl_cnt, 993 &trl_uio); 994 if (error != 0) 995 goto out; 996 } 997 } 998 999 AUDIT_ARG_FD(uap->fd); 1000 1001 /* 1002 * sendfile(2) can start at any offset within a file so we require 1003 * CAP_READ+CAP_SEEK = CAP_PREAD. 1004 */ 1005 if ((error = fget_read(td, uap->fd, 1006 cap_rights_init(&rights, CAP_PREAD), &fp)) != 0) { 1007 goto out; 1008 } 1009 1010 error = fo_sendfile(fp, uap->s, hdr_uio, trl_uio, uap->offset, 1011 uap->nbytes, &sbytes, uap->flags, td); 1012 fdrop(fp, td); 1013 1014 if (uap->sbytes != NULL) 1015 copyout(&sbytes, uap->sbytes, sizeof(off_t)); 1016 1017 out: 1018 free(hdr_uio, M_IOV); 1019 free(trl_uio, M_IOV); 1020 return (error); 1021 } 1022 1023 /* 1024 * sendfile(2) 1025 * 1026 * int sendfile(int fd, int s, off_t offset, size_t nbytes, 1027 * struct sf_hdtr *hdtr, off_t *sbytes, int flags) 1028 * 1029 * Send a file specified by 'fd' and starting at 'offset' to a socket 1030 * specified by 's'. Send only 'nbytes' of the file or until EOF if nbytes == 1031 * 0. Optionally add a header and/or trailer to the socket output. If 1032 * specified, write the total number of bytes sent into *sbytes. 1033 */ 1034 int 1035 sys_sendfile(struct thread *td, struct sendfile_args *uap) 1036 { 1037 1038 return (sendfile(td, uap, 0)); 1039 } 1040 1041 #ifdef COMPAT_FREEBSD4 1042 int 1043 freebsd4_sendfile(struct thread *td, struct freebsd4_sendfile_args *uap) 1044 { 1045 struct sendfile_args args; 1046 1047 args.fd = uap->fd; 1048 args.s = uap->s; 1049 args.offset = uap->offset; 1050 args.nbytes = uap->nbytes; 1051 args.hdtr = uap->hdtr; 1052 args.sbytes = uap->sbytes; 1053 args.flags = uap->flags; 1054 1055 return (sendfile(td, &args, 1)); 1056 } 1057 #endif /* COMPAT_FREEBSD4 */ 1058