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

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