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