Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_sendfile.c
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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 <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/capsicum.h> 36 #include <sys/kernel.h> 37 #include <sys/lock.h> 38 #include <sys/mutex.h> 39 #include <sys/malloc.h> 40 #include <sys/mman.h> 41 #include <sys/mount.h> 42 #include <sys/mbuf.h> 43 #include <sys/proc.h> 44 #include <sys/protosw.h> 45 #include <sys/rwlock.h> 46 #include <sys/sf_buf.h> 47 #include <sys/socket.h> 48 #include <sys/socketvar.h> 49 #include <sys/syscallsubr.h> 50 #include <sys/sysctl.h> 51 #include <sys/sysproto.h> 52 #include <sys/vnode.h> 53 54 #include <net/vnet.h> 55 56 #include <netinet/in.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 static MALLOC_DEFINE(M_SENDFILE, "sendfile", "sendfile dynamic memory"); 66 67 #define EXT_FLAG_SYNC EXT_FLAG_VENDOR1 68 #define EXT_FLAG_NOCACHE EXT_FLAG_VENDOR2 69 70 /* 71 * Structure describing a single sendfile(2) I/O, which may consist of 72 * several underlying pager I/Os. 73 * 74 * The syscall context allocates the structure and initializes 'nios' 75 * to 1. As sendfile_swapin() runs through pages and starts asynchronous 76 * paging operations, it increments 'nios'. 77 * 78 * Every I/O completion calls sendfile_iodone(), which decrements the 'nios', 79 * and the syscall also calls sendfile_iodone() after allocating all mbufs, 80 * linking them and sending to socket. Whoever reaches zero 'nios' is 81 * responsible to * call pru_ready on the socket, to notify it of readyness 82 * of the data. 83 */ 84 struct sf_io { 85 volatile u_int nios; 86 u_int error; 87 int npages; 88 struct socket *so; 89 struct mbuf *m; 90 vm_page_t pa[]; 91 }; 92 93 /* 94 * Structure used to track requests with SF_SYNC flag. 95 */ 96 struct sendfile_sync { 97 struct mtx mtx; 98 struct cv cv; 99 unsigned count; 100 bool waiting; 101 }; 102 103 static void 104 sendfile_sync_destroy(struct sendfile_sync *sfs) 105 { 106 KASSERT(sfs->count == 0, ("sendfile sync %p still busy", sfs)); 107 108 cv_destroy(&sfs->cv); 109 mtx_destroy(&sfs->mtx); 110 free(sfs, M_SENDFILE); 111 } 112 113 static void 114 sendfile_sync_signal(struct sendfile_sync *sfs) 115 { 116 mtx_lock(&sfs->mtx); 117 KASSERT(sfs->count > 0, ("sendfile sync %p not busy", sfs)); 118 if (--sfs->count == 0) { 119 if (!sfs->waiting) { 120 /* The sendfile() waiter was interrupted by a signal. */ 121 sendfile_sync_destroy(sfs); 122 return; 123 } else { 124 cv_signal(&sfs->cv); 125 } 126 } 127 mtx_unlock(&sfs->mtx); 128 } 129 130 counter_u64_t sfstat[sizeof(struct sfstat) / sizeof(uint64_t)]; 131 132 static void 133 sfstat_init(const void *unused) 134 { 135 136 COUNTER_ARRAY_ALLOC(sfstat, sizeof(struct sfstat) / sizeof(uint64_t), 137 M_WAITOK); 138 } 139 SYSINIT(sfstat, SI_SUB_MBUF, SI_ORDER_FIRST, sfstat_init, NULL); 140 141 static int 142 sfstat_sysctl(SYSCTL_HANDLER_ARGS) 143 { 144 struct sfstat s; 145 146 COUNTER_ARRAY_COPY(sfstat, &s, sizeof(s) / sizeof(uint64_t)); 147 if (req->newptr) 148 COUNTER_ARRAY_ZERO(sfstat, sizeof(s) / sizeof(uint64_t)); 149 return (SYSCTL_OUT(req, &s, sizeof(s))); 150 } 151 SYSCTL_PROC(_kern_ipc, OID_AUTO, sfstat, CTLTYPE_OPAQUE | CTLFLAG_RW, 152 NULL, 0, sfstat_sysctl, "I", "sendfile statistics"); 153 154 static void 155 sendfile_free_mext(struct mbuf *m) 156 { 157 struct sf_buf *sf; 158 vm_page_t pg; 159 int flags; 160 161 KASSERT(m->m_flags & M_EXT && m->m_ext.ext_type == EXT_SFBUF, 162 ("%s: m %p !M_EXT or !EXT_SFBUF", __func__, m)); 163 164 sf = m->m_ext.ext_arg1; 165 pg = sf_buf_page(sf); 166 flags = (m->m_ext.ext_flags & EXT_FLAG_NOCACHE) != 0 ? VPR_TRYFREE : 0; 167 168 sf_buf_free(sf); 169 vm_page_release(pg, flags); 170 171 if (m->m_ext.ext_flags & EXT_FLAG_SYNC) { 172 struct sendfile_sync *sfs = m->m_ext.ext_arg2; 173 sendfile_sync_signal(sfs); 174 } 175 } 176 177 /* 178 * Helper function to calculate how much data to put into page i of n. 179 * Only first and last pages are special. 180 */ 181 static inline off_t 182 xfsize(int i, int n, off_t off, off_t len) 183 { 184 185 if (i == 0) 186 return (omin(PAGE_SIZE - (off & PAGE_MASK), len)); 187 188 if (i == n - 1 && ((off + len) & PAGE_MASK) > 0) 189 return ((off + len) & PAGE_MASK); 190 191 return (PAGE_SIZE); 192 } 193 194 /* 195 * Helper function to get offset within object for i page. 196 */ 197 static inline vm_ooffset_t 198 vmoff(int i, off_t off) 199 { 200 201 if (i == 0) 202 return ((vm_ooffset_t)off); 203 204 return (trunc_page(off + i * PAGE_SIZE)); 205 } 206 207 /* 208 * Helper function used when allocation of a page or sf_buf failed. 209 * Pretend as if we don't have enough space, subtract xfsize() of 210 * all pages that failed. 211 */ 212 static inline void 213 fixspace(int old, int new, off_t off, int *space) 214 { 215 216 KASSERT(old > new, ("%s: old %d new %d", __func__, old, new)); 217 218 /* Subtract last one. */ 219 *space -= xfsize(old - 1, old, off, *space); 220 old--; 221 222 if (new == old) 223 /* There was only one page. */ 224 return; 225 226 /* Subtract first one. */ 227 if (new == 0) { 228 *space -= xfsize(0, old, off, *space); 229 new++; 230 } 231 232 /* Rest of pages are full sized. */ 233 *space -= (old - new) * PAGE_SIZE; 234 235 KASSERT(*space >= 0, ("%s: space went backwards", __func__)); 236 } 237 238 /* 239 * I/O completion callback. 240 */ 241 static void 242 sendfile_iodone(void *arg, vm_page_t *pg, int count, int error) 243 { 244 struct sf_io *sfio = arg; 245 struct socket *so = sfio->so; 246 247 for (int i = 0; i < count; i++) 248 if (pg[i] != bogus_page) 249 vm_page_xunbusy(pg[i]); 250 251 if (error) 252 sfio->error = error; 253 254 if (!refcount_release(&sfio->nios)) 255 return; 256 257 CURVNET_SET(so->so_vnet); 258 if (sfio->error) { 259 struct mbuf *m; 260 261 /* 262 * I/O operation failed. The state of data in the socket 263 * is now inconsistent, and all what we can do is to tear 264 * it down. Protocol abort method would tear down protocol 265 * state, free all ready mbufs and detach not ready ones. 266 * We will free the mbufs corresponding to this I/O manually. 267 * 268 * The socket would be marked with EIO and made available 269 * for read, so that application receives EIO on next 270 * syscall and eventually closes the socket. 271 */ 272 so->so_proto->pr_usrreqs->pru_abort(so); 273 so->so_error = EIO; 274 275 m = sfio->m; 276 for (int i = 0; i < sfio->npages; i++) 277 m = m_free(m); 278 } else 279 (void )(so->so_proto->pr_usrreqs->pru_ready)(so, sfio->m, 280 sfio->npages); 281 282 SOCK_LOCK(so); 283 sorele(so); 284 CURVNET_RESTORE(); 285 free(sfio, M_SENDFILE); 286 } 287 288 /* 289 * Iterate through pages vector and request paging for non-valid pages. 290 */ 291 static int 292 sendfile_swapin(vm_object_t obj, struct sf_io *sfio, int *nios, off_t off, 293 off_t len, int npages, int rhpages, int flags) 294 { 295 vm_page_t *pa = sfio->pa; 296 int grabbed; 297 298 *nios = 0; 299 flags = (flags & SF_NODISKIO) ? VM_ALLOC_NOWAIT : 0; 300 301 /* 302 * First grab all the pages and wire them. Note that we grab 303 * only required pages. Readahead pages are dealt with later. 304 */ 305 VM_OBJECT_WLOCK(obj); 306 307 grabbed = vm_page_grab_pages(obj, OFF_TO_IDX(off), 308 VM_ALLOC_NORMAL | VM_ALLOC_WIRED | flags, pa, npages); 309 if (grabbed < npages) { 310 for (int i = grabbed; i < npages; i++) 311 pa[i] = NULL; 312 npages = grabbed; 313 rhpages = 0; 314 } 315 316 for (int i = 0; i < npages;) { 317 int j, a, count, rv; 318 319 /* Skip valid pages. */ 320 if (vm_page_is_valid(pa[i], vmoff(i, off) & PAGE_MASK, 321 xfsize(i, npages, off, len))) { 322 vm_page_xunbusy(pa[i]); 323 SFSTAT_INC(sf_pages_valid); 324 i++; 325 continue; 326 } 327 328 /* 329 * Next page is invalid. Check if it belongs to pager. It 330 * may not be there, which is a regular situation for shmem 331 * pager. For vnode pager this happens only in case of 332 * a sparse file. 333 * 334 * Important feature of vm_pager_has_page() is the hint 335 * stored in 'a', about how many pages we can pagein after 336 * this page in a single I/O. 337 */ 338 if (!vm_pager_has_page(obj, OFF_TO_IDX(vmoff(i, off)), NULL, 339 &a)) { 340 pmap_zero_page(pa[i]); 341 pa[i]->valid = VM_PAGE_BITS_ALL; 342 MPASS(pa[i]->dirty == 0); 343 vm_page_xunbusy(pa[i]); 344 i++; 345 continue; 346 } 347 348 /* 349 * We want to pagein as many pages as possible, limited only 350 * by the 'a' hint and actual request. 351 */ 352 count = min(a + 1, npages - i); 353 354 /* 355 * We should not pagein into a valid page, thus we first trim 356 * any valid pages off the end of request, and substitute 357 * to bogus_page those, that are in the middle. 358 */ 359 for (j = i + count - 1; j > i; j--) { 360 if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK, 361 xfsize(j, npages, off, len))) { 362 count--; 363 rhpages = 0; 364 } else 365 break; 366 } 367 for (j = i + 1; j < i + count - 1; j++) 368 if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK, 369 xfsize(j, npages, off, len))) { 370 vm_page_xunbusy(pa[j]); 371 SFSTAT_INC(sf_pages_valid); 372 SFSTAT_INC(sf_pages_bogus); 373 pa[j] = bogus_page; 374 } 375 376 refcount_acquire(&sfio->nios); 377 rv = vm_pager_get_pages_async(obj, pa + i, count, NULL, 378 i + count == npages ? &rhpages : NULL, 379 &sendfile_iodone, sfio); 380 if (rv != VM_PAGER_OK) { 381 for (j = i; j < i + count; j++) { 382 if (pa[j] != bogus_page) { 383 vm_page_lock(pa[j]); 384 vm_page_unwire(pa[j], PQ_INACTIVE); 385 vm_page_unlock(pa[j]); 386 } 387 } 388 VM_OBJECT_WUNLOCK(obj); 389 return (EIO); 390 } 391 KASSERT(rv == VM_PAGER_OK, ("%s: pager fail obj %p page %p", 392 __func__, obj, pa[i])); 393 394 SFSTAT_INC(sf_iocnt); 395 SFSTAT_ADD(sf_pages_read, count); 396 if (i + count == npages) 397 SFSTAT_ADD(sf_rhpages_read, rhpages); 398 399 /* 400 * Restore the valid page pointers. They are already 401 * unbusied, but still wired. 402 */ 403 for (j = i; j < i + count; j++) 404 if (pa[j] == bogus_page) { 405 pa[j] = vm_page_lookup(obj, 406 OFF_TO_IDX(vmoff(j, off))); 407 KASSERT(pa[j], ("%s: page %p[%d] disappeared", 408 __func__, pa, j)); 409 410 } 411 i += count; 412 (*nios)++; 413 } 414 415 VM_OBJECT_WUNLOCK(obj); 416 417 if (*nios == 0 && npages != 0) 418 SFSTAT_INC(sf_noiocnt); 419 420 return (0); 421 } 422 423 static int 424 sendfile_getobj(struct thread *td, struct file *fp, vm_object_t *obj_res, 425 struct vnode **vp_res, struct shmfd **shmfd_res, off_t *obj_size, 426 int *bsize) 427 { 428 struct vattr va; 429 vm_object_t obj; 430 struct vnode *vp; 431 struct shmfd *shmfd; 432 int error; 433 434 vp = *vp_res = NULL; 435 obj = NULL; 436 shmfd = *shmfd_res = NULL; 437 *bsize = 0; 438 439 /* 440 * The file descriptor must be a regular file and have a 441 * backing VM object. 442 */ 443 if (fp->f_type == DTYPE_VNODE) { 444 vp = fp->f_vnode; 445 vn_lock(vp, LK_SHARED | LK_RETRY); 446 if (vp->v_type != VREG) { 447 error = EINVAL; 448 goto out; 449 } 450 *bsize = vp->v_mount->mnt_stat.f_iosize; 451 error = VOP_GETATTR(vp, &va, td->td_ucred); 452 if (error != 0) 453 goto out; 454 *obj_size = va.va_size; 455 obj = vp->v_object; 456 if (obj == NULL) { 457 error = EINVAL; 458 goto out; 459 } 460 } else if (fp->f_type == DTYPE_SHM) { 461 error = 0; 462 shmfd = fp->f_data; 463 obj = shmfd->shm_object; 464 *obj_size = shmfd->shm_size; 465 } else { 466 error = EINVAL; 467 goto out; 468 } 469 470 VM_OBJECT_WLOCK(obj); 471 if ((obj->flags & OBJ_DEAD) != 0) { 472 VM_OBJECT_WUNLOCK(obj); 473 error = EBADF; 474 goto out; 475 } 476 477 /* 478 * Temporarily increase the backing VM object's reference 479 * count so that a forced reclamation of its vnode does not 480 * immediately destroy it. 481 */ 482 vm_object_reference_locked(obj); 483 VM_OBJECT_WUNLOCK(obj); 484 *obj_res = obj; 485 *vp_res = vp; 486 *shmfd_res = shmfd; 487 488 out: 489 if (vp != NULL) 490 VOP_UNLOCK(vp, 0); 491 return (error); 492 } 493 494 static int 495 sendfile_getsock(struct thread *td, int s, struct file **sock_fp, 496 struct socket **so) 497 { 498 int error; 499 500 *sock_fp = NULL; 501 *so = NULL; 502 503 /* 504 * The socket must be a stream socket and connected. 505 */ 506 error = getsock_cap(td, s, &cap_send_rights, 507 sock_fp, NULL, NULL); 508 if (error != 0) 509 return (error); 510 *so = (*sock_fp)->f_data; 511 if ((*so)->so_type != SOCK_STREAM) 512 return (EINVAL); 513 /* 514 * SCTP one-to-one style sockets currently don't work with 515 * sendfile(). So indicate EINVAL for now. 516 */ 517 if ((*so)->so_proto->pr_protocol == IPPROTO_SCTP) 518 return (EINVAL); 519 if (SOLISTENING(*so)) 520 return (ENOTCONN); 521 return (0); 522 } 523 524 int 525 vn_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio, 526 struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags, 527 struct thread *td) 528 { 529 struct file *sock_fp; 530 struct vnode *vp; 531 struct vm_object *obj; 532 struct socket *so; 533 struct mbuf *m, *mh, *mhtail; 534 struct sf_buf *sf; 535 struct shmfd *shmfd; 536 struct sendfile_sync *sfs; 537 struct vattr va; 538 off_t off, sbytes, rem, obj_size; 539 int error, softerr, bsize, hdrlen; 540 541 obj = NULL; 542 so = NULL; 543 m = mh = NULL; 544 sfs = NULL; 545 hdrlen = sbytes = 0; 546 softerr = 0; 547 548 error = sendfile_getobj(td, fp, &obj, &vp, &shmfd, &obj_size, &bsize); 549 if (error != 0) 550 return (error); 551 552 error = sendfile_getsock(td, sockfd, &sock_fp, &so); 553 if (error != 0) 554 goto out; 555 556 #ifdef MAC 557 error = mac_socket_check_send(td->td_ucred, so); 558 if (error != 0) 559 goto out; 560 #endif 561 562 SFSTAT_INC(sf_syscalls); 563 SFSTAT_ADD(sf_rhpages_requested, SF_READAHEAD(flags)); 564 565 if (flags & SF_SYNC) { 566 sfs = malloc(sizeof(*sfs), M_SENDFILE, M_WAITOK | M_ZERO); 567 mtx_init(&sfs->mtx, "sendfile", NULL, MTX_DEF); 568 cv_init(&sfs->cv, "sendfile"); 569 sfs->waiting = true; 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_SENDFILE, M_WAITOK); 733 refcount_init(&sfio->nios, 1); 734 sfio->so = so; 735 sfio->error = 0; 736 737 error = sendfile_swapin(obj, sfio, &nios, off, space, npages, 738 rhpages, flags); 739 if (error != 0) { 740 if (vp != NULL) 741 VOP_UNLOCK(vp, 0); 742 free(sfio, M_SENDFILE); 743 goto done; 744 } 745 746 /* 747 * Loop and construct maximum sized mbuf chain to be bulk 748 * dumped into socket buffer. 749 */ 750 pa = sfio->pa; 751 for (int i = 0; i < npages; i++) { 752 struct mbuf *m0; 753 754 /* 755 * If a page wasn't grabbed successfully, then 756 * trim the array. Can happen only with SF_NODISKIO. 757 */ 758 if (pa[i] == NULL) { 759 SFSTAT_INC(sf_busy); 760 fixspace(npages, i, off, &space); 761 npages = i; 762 softerr = EBUSY; 763 break; 764 } 765 766 /* 767 * Get a sendfile buf. When allocating the 768 * first buffer for mbuf chain, we usually 769 * wait as long as necessary, but this wait 770 * can be interrupted. For consequent 771 * buffers, do not sleep, since several 772 * threads might exhaust the buffers and then 773 * deadlock. 774 */ 775 sf = sf_buf_alloc(pa[i], 776 m != NULL ? SFB_NOWAIT : SFB_CATCH); 777 if (sf == NULL) { 778 SFSTAT_INC(sf_allocfail); 779 for (int j = i; j < npages; j++) { 780 vm_page_lock(pa[j]); 781 vm_page_unwire(pa[j], PQ_INACTIVE); 782 vm_page_unlock(pa[j]); 783 } 784 if (m == NULL) 785 softerr = ENOBUFS; 786 fixspace(npages, i, off, &space); 787 npages = i; 788 break; 789 } 790 791 m0 = m_get(M_WAITOK, MT_DATA); 792 m0->m_ext.ext_buf = (char *)sf_buf_kva(sf); 793 m0->m_ext.ext_size = PAGE_SIZE; 794 m0->m_ext.ext_arg1 = sf; 795 m0->m_ext.ext_type = EXT_SFBUF; 796 m0->m_ext.ext_flags = EXT_FLAG_EMBREF; 797 m0->m_ext.ext_free = sendfile_free_mext; 798 /* 799 * SF_NOCACHE sets the page as being freed upon send. 800 * However, we ignore it for the last page in 'space', 801 * if the page is truncated, and we got more data to 802 * send (rem > space), or if we have readahead 803 * configured (rhpages > 0). 804 */ 805 if ((flags & SF_NOCACHE) && 806 (i != npages - 1 || 807 !((off + space) & PAGE_MASK) || 808 !(rem > space || rhpages > 0))) 809 m0->m_ext.ext_flags |= EXT_FLAG_NOCACHE; 810 if (sfs != NULL) { 811 m0->m_ext.ext_flags |= EXT_FLAG_SYNC; 812 m0->m_ext.ext_arg2 = sfs; 813 mtx_lock(&sfs->mtx); 814 sfs->count++; 815 mtx_unlock(&sfs->mtx); 816 } 817 m0->m_ext.ext_count = 1; 818 m0->m_flags |= (M_EXT | M_RDONLY); 819 if (nios) 820 m0->m_flags |= M_NOTREADY; 821 m0->m_data = (char *)sf_buf_kva(sf) + 822 (vmoff(i, off) & PAGE_MASK); 823 m0->m_len = xfsize(i, npages, off, space); 824 825 if (i == 0) 826 sfio->m = m0; 827 828 /* Append to mbuf chain. */ 829 if (mtail != NULL) 830 mtail->m_next = m0; 831 else 832 m = m0; 833 mtail = m0; 834 } 835 836 if (vp != NULL) 837 VOP_UNLOCK(vp, 0); 838 839 /* Keep track of bytes processed. */ 840 off += space; 841 rem -= space; 842 843 /* Prepend header, if any. */ 844 if (hdrlen) { 845 prepend_header: 846 mhtail->m_next = m; 847 m = mh; 848 mh = NULL; 849 } 850 851 if (m == NULL) { 852 KASSERT(softerr, ("%s: m NULL, no error", __func__)); 853 error = softerr; 854 free(sfio, M_SENDFILE); 855 goto done; 856 } 857 858 /* Add the buffer chain to the socket buffer. */ 859 KASSERT(m_length(m, NULL) == space + hdrlen, 860 ("%s: mlen %u space %d hdrlen %d", 861 __func__, m_length(m, NULL), space, hdrlen)); 862 863 CURVNET_SET(so->so_vnet); 864 if (nios == 0) { 865 /* 866 * If sendfile_swapin() didn't initiate any I/Os, 867 * which happens if all data is cached in VM, then 868 * we can send data right now without the 869 * PRUS_NOTREADY flag. 870 */ 871 free(sfio, M_SENDFILE); 872 error = (*so->so_proto->pr_usrreqs->pru_send) 873 (so, 0, m, NULL, NULL, td); 874 } else { 875 sfio->npages = npages; 876 soref(so); 877 error = (*so->so_proto->pr_usrreqs->pru_send) 878 (so, PRUS_NOTREADY, m, NULL, NULL, td); 879 sendfile_iodone(sfio, NULL, 0, 0); 880 } 881 CURVNET_RESTORE(); 882 883 m = NULL; /* pru_send always consumes */ 884 if (error) 885 goto done; 886 sbytes += space + hdrlen; 887 if (hdrlen) 888 hdrlen = 0; 889 if (softerr) { 890 error = softerr; 891 goto done; 892 } 893 } 894 895 /* 896 * Send trailers. Wimp out and use writev(2). 897 */ 898 if (trl_uio != NULL) { 899 sbunlock(&so->so_snd); 900 error = kern_writev(td, sockfd, trl_uio); 901 if (error == 0) 902 sbytes += td->td_retval[0]; 903 goto out; 904 } 905 906 done: 907 sbunlock(&so->so_snd); 908 out: 909 /* 910 * If there was no error we have to clear td->td_retval[0] 911 * because it may have been set by writev. 912 */ 913 if (error == 0) { 914 td->td_retval[0] = 0; 915 } 916 if (sent != NULL) { 917 (*sent) = sbytes; 918 } 919 if (obj != NULL) 920 vm_object_deallocate(obj); 921 if (so) 922 fdrop(sock_fp, td); 923 if (m) 924 m_freem(m); 925 if (mh) 926 m_freem(mh); 927 928 if (sfs != NULL) { 929 mtx_lock(&sfs->mtx); 930 if (sfs->count != 0) 931 error = cv_wait_sig(&sfs->cv, &sfs->mtx); 932 if (sfs->count == 0) { 933 sendfile_sync_destroy(sfs); 934 } else { 935 sfs->waiting = false; 936 mtx_unlock(&sfs->mtx); 937 } 938 } 939 940 if (error == ERESTART) 941 error = EINTR; 942 943 return (error); 944 } 945 946 static int 947 sendfile(struct thread *td, struct sendfile_args *uap, int compat) 948 { 949 struct sf_hdtr hdtr; 950 struct uio *hdr_uio, *trl_uio; 951 struct file *fp; 952 off_t sbytes; 953 int error; 954 955 /* 956 * File offset must be positive. If it goes beyond EOF 957 * we send only the header/trailer and no payload data. 958 */ 959 if (uap->offset < 0) 960 return (EINVAL); 961 962 sbytes = 0; 963 hdr_uio = trl_uio = NULL; 964 965 if (uap->hdtr != NULL) { 966 error = copyin(uap->hdtr, &hdtr, sizeof(hdtr)); 967 if (error != 0) 968 goto out; 969 if (hdtr.headers != NULL) { 970 error = copyinuio(hdtr.headers, hdtr.hdr_cnt, 971 &hdr_uio); 972 if (error != 0) 973 goto out; 974 #ifdef COMPAT_FREEBSD4 975 /* 976 * In FreeBSD < 5.0 the nbytes to send also included 977 * the header. If compat is specified subtract the 978 * header size from nbytes. 979 */ 980 if (compat) { 981 if (uap->nbytes > hdr_uio->uio_resid) 982 uap->nbytes -= hdr_uio->uio_resid; 983 else 984 uap->nbytes = 0; 985 } 986 #endif 987 } 988 if (hdtr.trailers != NULL) { 989 error = copyinuio(hdtr.trailers, hdtr.trl_cnt, 990 &trl_uio); 991 if (error != 0) 992 goto out; 993 } 994 } 995 996 AUDIT_ARG_FD(uap->fd); 997 998 /* 999 * sendfile(2) can start at any offset within a file so we require 1000 * CAP_READ+CAP_SEEK = CAP_PREAD. 1001 */ 1002 if ((error = fget_read(td, uap->fd, &cap_pread_rights, &fp)) != 0) 1003 goto out; 1004 1005 error = fo_sendfile(fp, uap->s, hdr_uio, trl_uio, uap->offset, 1006 uap->nbytes, &sbytes, uap->flags, td); 1007 fdrop(fp, td); 1008 1009 if (uap->sbytes != NULL) 1010 copyout(&sbytes, uap->sbytes, sizeof(off_t)); 1011 1012 out: 1013 free(hdr_uio, M_IOV); 1014 free(trl_uio, M_IOV); 1015 return (error); 1016 } 1017 1018 /* 1019 * sendfile(2) 1020 * 1021 * int sendfile(int fd, int s, off_t offset, size_t nbytes, 1022 * struct sf_hdtr *hdtr, off_t *sbytes, int flags) 1023 * 1024 * Send a file specified by 'fd' and starting at 'offset' to a socket 1025 * specified by 's'. Send only 'nbytes' of the file or until EOF if nbytes == 1026 * 0. Optionally add a header and/or trailer to the socket output. If 1027 * specified, write the total number of bytes sent into *sbytes. 1028 */ 1029 int 1030 sys_sendfile(struct thread *td, struct sendfile_args *uap) 1031 { 1032 1033 return (sendfile(td, uap, 0)); 1034 } 1035 1036 #ifdef COMPAT_FREEBSD4 1037 int 1038 freebsd4_sendfile(struct thread *td, struct freebsd4_sendfile_args *uap) 1039 { 1040 struct sendfile_args args; 1041 1042 args.fd = uap->fd; 1043 args.s = uap->s; 1044 args.offset = uap->offset; 1045 args.nbytes = uap->nbytes; 1046 args.hdtr = uap->hdtr; 1047 args.sbytes = uap->sbytes; 1048 args.flags = uap->flags; 1049 1050 return (sendfile(td, &args, 1)); 1051 } 1052 #endif /* COMPAT_FREEBSD4 */
Cache object: a60b869e811916d9ff77daed6546d054
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