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freebsd-dev/sys/kern/kern_sendfile.c

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/*-
* Copyright (c) 2013-2015 Gleb Smirnoff <glebius@FreeBSD.org>
* Copyright (c) 1998, David Greenman. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/capsicum.h>
#include <sys/kernel.h>
#include <netinet/in.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sysproto.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/rwlock.h>
#include <sys/sf_buf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <net/vnet.h>
#include <security/audit/audit.h>
#include <security/mac/mac_framework.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#define EXT_FLAG_SYNC EXT_FLAG_VENDOR1
#define EXT_FLAG_NOCACHE EXT_FLAG_VENDOR2
#define EXT_FLAG_CACHE_LAST EXT_FLAG_VENDOR3
/*
* Structure describing a single sendfile(2) I/O, which may consist of
* several underlying pager I/Os.
*
* The syscall context allocates the structure and initializes 'nios'
* to 1. As sendfile_swapin() runs through pages and starts asynchronous
* paging operations, it increments 'nios'.
*
* Every I/O completion calls sendfile_iodone(), which decrements the 'nios',
* and the syscall also calls sendfile_iodone() after allocating all mbufs,
* linking them and sending to socket. Whoever reaches zero 'nios' is
* responsible to * call pru_ready on the socket, to notify it of readyness
* of the data.
*/
struct sf_io {
volatile u_int nios;
u_int error;
int npages;
struct socket *so;
struct mbuf *m;
vm_page_t pa[];
};
/*
* Structure used to track requests with SF_SYNC flag.
*/
struct sendfile_sync {
struct mtx mtx;
struct cv cv;
unsigned count;
};
counter_u64_t sfstat[sizeof(struct sfstat) / sizeof(uint64_t)];
static void
sfstat_init(const void *unused)
{
COUNTER_ARRAY_ALLOC(sfstat, sizeof(struct sfstat) / sizeof(uint64_t),
M_WAITOK);
}
SYSINIT(sfstat, SI_SUB_MBUF, SI_ORDER_FIRST, sfstat_init, NULL);
static int
sfstat_sysctl(SYSCTL_HANDLER_ARGS)
{
struct sfstat s;
COUNTER_ARRAY_COPY(sfstat, &s, sizeof(s) / sizeof(uint64_t));
if (req->newptr)
COUNTER_ARRAY_ZERO(sfstat, sizeof(s) / sizeof(uint64_t));
return (SYSCTL_OUT(req, &s, sizeof(s)));
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, sfstat, CTLTYPE_OPAQUE | CTLFLAG_RW,
NULL, 0, sfstat_sysctl, "I", "sendfile statistics");
static void
sendfile_free_mext(struct mbuf *m)
{
struct sf_buf *sf;
vm_page_t pg;
int flags;
KASSERT(m->m_flags & M_EXT && m->m_ext.ext_type == EXT_SFBUF,
("%s: m %p !M_EXT or !EXT_SFBUF", __func__, m));
sf = m->m_ext.ext_arg1;
pg = sf_buf_page(sf);
flags = (m->m_ext.ext_flags & EXT_FLAG_NOCACHE) != 0 ? VPR_TRYFREE : 0;
sf_buf_free(sf);
vm_page_release(pg, flags);
if (m->m_ext.ext_flags & EXT_FLAG_SYNC) {
struct sendfile_sync *sfs = m->m_ext.ext_arg2;
mtx_lock(&sfs->mtx);
KASSERT(sfs->count > 0, ("Sendfile sync botchup count == 0"));
if (--sfs->count == 0)
cv_signal(&sfs->cv);
mtx_unlock(&sfs->mtx);
}
}
static void
sendfile_free_mext_pg(struct mbuf *m)
{
struct mbuf_ext_pgs *ext_pgs;
vm_page_t pg;
int flags, i;
bool cache_last;
KASSERT(m->m_flags & M_EXT && m->m_ext.ext_type == EXT_PGS,
("%s: m %p !M_EXT or !EXT_PGS", __func__, m));
cache_last = m->m_ext.ext_flags & EXT_FLAG_CACHE_LAST;
ext_pgs = m->m_ext.ext_pgs;
flags = (m->m_ext.ext_flags & EXT_FLAG_NOCACHE) != 0 ? VPR_TRYFREE : 0;
for (i = 0; i < ext_pgs->npgs; i++) {
if (cache_last && i == ext_pgs->npgs - 1)
flags = 0;
pg = PHYS_TO_VM_PAGE(ext_pgs->pa[i]);
vm_page_release(pg, flags);
}
if (m->m_ext.ext_flags & EXT_FLAG_SYNC) {
struct sendfile_sync *sfs = m->m_ext.ext_arg2;
mtx_lock(&sfs->mtx);
KASSERT(sfs->count > 0, ("Sendfile sync botchup count == 0"));
if (--sfs->count == 0)
cv_signal(&sfs->cv);
mtx_unlock(&sfs->mtx);
}
}
/*
* Helper function to calculate how much data to put into page i of n.
* Only first and last pages are special.
*/
static inline off_t
xfsize(int i, int n, off_t off, off_t len)
{
if (i == 0)
return (omin(PAGE_SIZE - (off & PAGE_MASK), len));
if (i == n - 1 && ((off + len) & PAGE_MASK) > 0)
return ((off + len) & PAGE_MASK);
return (PAGE_SIZE);
}
/*
* Helper function to get offset within object for i page.
*/
static inline vm_ooffset_t
vmoff(int i, off_t off)
{
if (i == 0)
return ((vm_ooffset_t)off);
return (trunc_page(off + i * PAGE_SIZE));
}
/*
* Helper function used when allocation of a page or sf_buf failed.
* Pretend as if we don't have enough space, subtract xfsize() of
* all pages that failed.
*/
static inline void
fixspace(int old, int new, off_t off, int *space)
{
KASSERT(old > new, ("%s: old %d new %d", __func__, old, new));
/* Subtract last one. */
*space -= xfsize(old - 1, old, off, *space);
old--;
if (new == old)
/* There was only one page. */
return;
/* Subtract first one. */
if (new == 0) {
*space -= xfsize(0, old, off, *space);
new++;
}
/* Rest of pages are full sized. */
*space -= (old - new) * PAGE_SIZE;
KASSERT(*space >= 0, ("%s: space went backwards", __func__));
}
/*
* I/O completion callback.
*/
static void
sendfile_iodone(void *arg, vm_page_t *pg, int count, int error)
{
struct sf_io *sfio = arg;
struct socket *so = sfio->so;
for (int i = 0; i < count; i++)
if (pg[i] != bogus_page)
vm_page_xunbusy(pg[i]);
if (error)
sfio->error = error;
if (!refcount_release(&sfio->nios))
return;
CURVNET_SET(so->so_vnet);
if (sfio->error) {
/*
* I/O operation failed. The state of data in the socket
* is now inconsistent, and all what we can do is to tear
* it down. Protocol abort method would tear down protocol
* state, free all ready mbufs and detach not ready ones.
* We will free the mbufs corresponding to this I/O manually.
*
* The socket would be marked with EIO and made available
* for read, so that application receives EIO on next
* syscall and eventually closes the socket.
*/
so->so_proto->pr_usrreqs->pru_abort(so);
so->so_error = EIO;
mb_free_notready(sfio->m, sfio->npages);
} else
(void)(so->so_proto->pr_usrreqs->pru_ready)(so, sfio->m,
sfio->npages);
SOCK_LOCK(so);
sorele(so);
CURVNET_RESTORE();
free(sfio, M_TEMP);
}
/*
* Iterate through pages vector and request paging for non-valid pages.
*/
static int
sendfile_swapin(vm_object_t obj, struct sf_io *sfio, int *nios, off_t off,
off_t len, int npages, int rhpages, int flags)
{
vm_page_t *pa = sfio->pa;
int grabbed;
*nios = 0;
flags = (flags & SF_NODISKIO) ? VM_ALLOC_NOWAIT : 0;
/*
* First grab all the pages and wire them. Note that we grab
* only required pages. Readahead pages are dealt with later.
*/
VM_OBJECT_WLOCK(obj);
grabbed = vm_page_grab_pages(obj, OFF_TO_IDX(off),
VM_ALLOC_NORMAL | VM_ALLOC_WIRED | flags, pa, npages);
if (grabbed < npages) {
for (int i = grabbed; i < npages; i++)
pa[i] = NULL;
npages = grabbed;
rhpages = 0;
}
for (int i = 0; i < npages;) {
int j, a, count, rv;
/* Skip valid pages. */
if (vm_page_is_valid(pa[i], vmoff(i, off) & PAGE_MASK,
xfsize(i, npages, off, len))) {
vm_page_xunbusy(pa[i]);
SFSTAT_INC(sf_pages_valid);
i++;
continue;
}
/*
* Next page is invalid. Check if it belongs to pager. It
* may not be there, which is a regular situation for shmem
* pager. For vnode pager this happens only in case of
* a sparse file.
*
* Important feature of vm_pager_has_page() is the hint
* stored in 'a', about how many pages we can pagein after
* this page in a single I/O.
*/
if (!vm_pager_has_page(obj, OFF_TO_IDX(vmoff(i, off)), NULL,
&a)) {
pmap_zero_page(pa[i]);
pa[i]->valid = VM_PAGE_BITS_ALL;
MPASS(pa[i]->dirty == 0);
vm_page_xunbusy(pa[i]);
i++;
continue;
}
/*
* We want to pagein as many pages as possible, limited only
* by the 'a' hint and actual request.
*/
count = min(a + 1, npages - i);
/*
* We should not pagein into a valid page, thus we first trim
* any valid pages off the end of request, and substitute
* to bogus_page those, that are in the middle.
*/
for (j = i + count - 1; j > i; j--) {
if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK,
xfsize(j, npages, off, len))) {
count--;
rhpages = 0;
} else
break;
}
for (j = i + 1; j < i + count - 1; j++)
if (vm_page_is_valid(pa[j], vmoff(j, off) & PAGE_MASK,
xfsize(j, npages, off, len))) {
vm_page_xunbusy(pa[j]);
SFSTAT_INC(sf_pages_valid);
SFSTAT_INC(sf_pages_bogus);
pa[j] = bogus_page;
}
refcount_acquire(&sfio->nios);
rv = vm_pager_get_pages_async(obj, pa + i, count, NULL,
i + count == npages ? &rhpages : NULL,
&sendfile_iodone, sfio);
if (rv != VM_PAGER_OK) {
for (j = i; j < i + count; j++) {
if (pa[j] != bogus_page) {
vm_page_lock(pa[j]);
vm_page_unwire(pa[j], PQ_INACTIVE);
vm_page_unlock(pa[j]);
}
}
VM_OBJECT_WUNLOCK(obj);
return (EIO);
}
SFSTAT_INC(sf_iocnt);
SFSTAT_ADD(sf_pages_read, count);
if (i + count == npages)
SFSTAT_ADD(sf_rhpages_read, rhpages);
/*
* Restore the valid page pointers. They are already
* unbusied, but still wired.
*/
for (j = i; j < i + count; j++)
if (pa[j] == bogus_page) {
pa[j] = vm_page_lookup(obj,
OFF_TO_IDX(vmoff(j, off)));
KASSERT(pa[j], ("%s: page %p[%d] disappeared",
__func__, pa, j));
}
i += count;
(*nios)++;
}
VM_OBJECT_WUNLOCK(obj);
if (*nios == 0 && npages != 0)
SFSTAT_INC(sf_noiocnt);
return (0);
}
static int
sendfile_getobj(struct thread *td, struct file *fp, vm_object_t *obj_res,
struct vnode **vp_res, struct shmfd **shmfd_res, off_t *obj_size,
int *bsize)
{
struct vattr va;
vm_object_t obj;
struct vnode *vp;
struct shmfd *shmfd;
int error;
vp = *vp_res = NULL;
obj = NULL;
shmfd = *shmfd_res = NULL;
*bsize = 0;
/*
* The file descriptor must be a regular file and have a
* backing VM object.
*/
if (fp->f_type == DTYPE_VNODE) {
vp = fp->f_vnode;
vn_lock(vp, LK_SHARED | LK_RETRY);
if (vp->v_type != VREG) {
error = EINVAL;
goto out;
}
*bsize = vp->v_mount->mnt_stat.f_iosize;
error = VOP_GETATTR(vp, &va, td->td_ucred);
if (error != 0)
goto out;
*obj_size = va.va_size;
obj = vp->v_object;
if (obj == NULL) {
error = EINVAL;
goto out;
}
} else if (fp->f_type == DTYPE_SHM) {
error = 0;
shmfd = fp->f_data;
obj = shmfd->shm_object;
*obj_size = shmfd->shm_size;
} else {
error = EINVAL;
goto out;
}
VM_OBJECT_WLOCK(obj);
if ((obj->flags & OBJ_DEAD) != 0) {
VM_OBJECT_WUNLOCK(obj);
error = EBADF;
goto out;
}
/*
* Temporarily increase the backing VM object's reference
* count so that a forced reclamation of its vnode does not
* immediately destroy it.
*/
vm_object_reference_locked(obj);
VM_OBJECT_WUNLOCK(obj);
*obj_res = obj;
*vp_res = vp;
*shmfd_res = shmfd;
out:
if (vp != NULL)
VOP_UNLOCK(vp, 0);
return (error);
}
static int
sendfile_getsock(struct thread *td, int s, struct file **sock_fp,
struct socket **so)
{
int error;
*sock_fp = NULL;
*so = NULL;
/*
* The socket must be a stream socket and connected.
*/
error = getsock_cap(td, s, &cap_send_rights,
sock_fp, NULL, NULL);
if (error != 0)
return (error);
*so = (*sock_fp)->f_data;
if ((*so)->so_type != SOCK_STREAM)
return (EINVAL);
if (SOLISTENING(*so))
return (ENOTCONN);
return (0);
}
int
vn_sendfile(struct file *fp, int sockfd, struct uio *hdr_uio,
struct uio *trl_uio, off_t offset, size_t nbytes, off_t *sent, int flags,
struct thread *td)
{
struct file *sock_fp;
struct vnode *vp;
struct vm_object *obj;
struct socket *so;
struct mbuf_ext_pgs *ext_pgs;
struct mbuf *m, *mh, *mhtail;
struct sf_buf *sf;
struct shmfd *shmfd;
struct sendfile_sync *sfs;
struct vattr va;
off_t off, sbytes, rem, obj_size;
int bsize, error, ext_pgs_idx, hdrlen, max_pgs, softerr;
bool use_ext_pgs;
obj = NULL;
so = NULL;
m = mh = NULL;
sfs = NULL;
hdrlen = sbytes = 0;
softerr = 0;
use_ext_pgs = false;
error = sendfile_getobj(td, fp, &obj, &vp, &shmfd, &obj_size, &bsize);
if (error != 0)
return (error);
error = sendfile_getsock(td, sockfd, &sock_fp, &so);
if (error != 0)
goto out;
#ifdef MAC
error = mac_socket_check_send(td->td_ucred, so);
if (error != 0)
goto out;
#endif
SFSTAT_INC(sf_syscalls);
SFSTAT_ADD(sf_rhpages_requested, SF_READAHEAD(flags));
if (flags & SF_SYNC) {
sfs = malloc(sizeof *sfs, M_TEMP, M_WAITOK | M_ZERO);
mtx_init(&sfs->mtx, "sendfile", NULL, MTX_DEF);
cv_init(&sfs->cv, "sendfile");
}
rem = nbytes ? omin(nbytes, obj_size - offset) : obj_size - offset;
/*
* Protect against multiple writers to the socket.
*
* XXXRW: Historically this has assumed non-interruptibility, so now
* we implement that, but possibly shouldn't.
*/
(void)sblock(&so->so_snd, SBL_WAIT | SBL_NOINTR);
/*
* Loop through the pages of the file, starting with the requested
* offset. Get a file page (do I/O if necessary), map the file page
* into an sf_buf, attach an mbuf header to the sf_buf, and queue
* it on the socket.
* This is done in two loops. The inner loop turns as many pages
* as it can, up to available socket buffer space, without blocking
* into mbufs to have it bulk delivered into the socket send buffer.
* The outer loop checks the state and available space of the socket
* and takes care of the overall progress.
*/
for (off = offset; rem > 0; ) {
struct sf_io *sfio;
vm_page_t *pa;
struct mbuf *mtail;
int nios, space, npages, rhpages;
mtail = NULL;
/*
* Check the socket state for ongoing connection,
* no errors and space in socket buffer.
* If space is low allow for the remainder of the
* file to be processed if it fits the socket buffer.
* Otherwise block in waiting for sufficient space
* to proceed, or if the socket is nonblocking, return
* to userland with EAGAIN while reporting how far
* we've come.
* We wait until the socket buffer has significant free
* space to do bulk sends. This makes good use of file
* system read ahead and allows packet segmentation
* offloading hardware to take over lots of work. If
* we were not careful here we would send off only one
* sfbuf at a time.
*/
SOCKBUF_LOCK(&so->so_snd);
if (so->so_snd.sb_lowat < so->so_snd.sb_hiwat / 2)
so->so_snd.sb_lowat = so->so_snd.sb_hiwat / 2;
retry_space:
if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
error = EPIPE;
SOCKBUF_UNLOCK(&so->so_snd);
goto done;
} else if (so->so_error) {
error = so->so_error;
so->so_error = 0;
SOCKBUF_UNLOCK(&so->so_snd);
goto done;
}
if ((so->so_state & SS_ISCONNECTED) == 0) {
SOCKBUF_UNLOCK(&so->so_snd);
error = ENOTCONN;
goto done;
}
space = sbspace(&so->so_snd);
if (space < rem &&
(space <= 0 ||
space < so->so_snd.sb_lowat)) {
if (so->so_state & SS_NBIO) {
SOCKBUF_UNLOCK(&so->so_snd);
error = EAGAIN;
goto done;
}
/*
* sbwait drops the lock while sleeping.
* When we loop back to retry_space the
* state may have changed and we retest
* for it.
*/
error = sbwait(&so->so_snd);
/*
* An error from sbwait usually indicates that we've
* been interrupted by a signal. If we've sent anything
* then return bytes sent, otherwise return the error.
*/
if (error != 0) {
SOCKBUF_UNLOCK(&so->so_snd);
goto done;
}
goto retry_space;
}
SOCKBUF_UNLOCK(&so->so_snd);
/*
* At the beginning of the first loop check if any headers
* are specified and copy them into mbufs. Reduce space in
* the socket buffer by the size of the header mbuf chain.
* Clear hdr_uio here and hdrlen at the end of the first loop.
*/
if (hdr_uio != NULL && hdr_uio->uio_resid > 0) {
hdr_uio->uio_td = td;
hdr_uio->uio_rw = UIO_WRITE;
mh = m_uiotombuf(hdr_uio, M_WAITOK, space, 0, 0);
hdrlen = m_length(mh, &mhtail);
space -= hdrlen;
/*
* If header consumed all the socket buffer space,
* don't waste CPU cycles and jump to the end.
*/
if (space == 0) {
sfio = NULL;
nios = 0;
goto prepend_header;
}
hdr_uio = NULL;
}
if (vp != NULL) {
error = vn_lock(vp, LK_SHARED);
if (error != 0)
goto done;
error = VOP_GETATTR(vp, &va, td->td_ucred);
if (error != 0 || off >= va.va_size) {
VOP_UNLOCK(vp, 0);
goto done;
}
if (va.va_size != obj_size) {
obj_size = va.va_size;
rem = nbytes ?
omin(nbytes + offset, obj_size) : obj_size;
rem -= off;
}
}
if (space > rem)
space = rem;
else if (space > PAGE_SIZE) {
/*
* Use page boundaries when possible for large
* requests.
*/
if (off & PAGE_MASK)
space -= (PAGE_SIZE - (off & PAGE_MASK));
space = trunc_page(space);
if (off & PAGE_MASK)
space += (PAGE_SIZE - (off & PAGE_MASK));
}
npages = howmany(space + (off & PAGE_MASK), PAGE_SIZE);
/*
* Calculate maximum allowed number of pages for readahead
* at this iteration. If SF_USER_READAHEAD was set, we don't
* do any heuristics and use exactly the value supplied by
* application. Otherwise, we allow readahead up to "rem".
* If application wants more, let it be, but there is no
* reason to go above MAXPHYS. Also check against "obj_size",
* since vm_pager_has_page() can hint beyond EOF.
*/
if (flags & SF_USER_READAHEAD) {
rhpages = SF_READAHEAD(flags);
} else {
rhpages = howmany(rem + (off & PAGE_MASK), PAGE_SIZE) -
npages;
rhpages += SF_READAHEAD(flags);
}
rhpages = min(howmany(MAXPHYS, PAGE_SIZE), rhpages);
rhpages = min(howmany(obj_size - trunc_page(off), PAGE_SIZE) -
npages, rhpages);
sfio = malloc(sizeof(struct sf_io) +
npages * sizeof(vm_page_t), M_TEMP, M_WAITOK);
refcount_init(&sfio->nios, 1);
sfio->so = so;
sfio->error = 0;
error = sendfile_swapin(obj, sfio, &nios, off, space, npages,
rhpages, flags);
if (error != 0) {
if (vp != NULL)
VOP_UNLOCK(vp, 0);
free(sfio, M_TEMP);
goto done;
}
/*
* Loop and construct maximum sized mbuf chain to be bulk
* dumped into socket buffer.
*/
pa = sfio->pa;
/*
* Use unmapped mbufs if enabled for TCP. Unmapped
* bufs are restricted to TCP as that is what has been
* tested. In particular, unmapped mbufs have not
* been tested with UNIX-domain sockets.
*/
if (mb_use_ext_pgs &&
so->so_proto->pr_protocol == IPPROTO_TCP) {
use_ext_pgs = true;
max_pgs = MBUF_PEXT_MAX_PGS;
/* Start at last index, to wrap on first use. */
ext_pgs_idx = max_pgs - 1;
}
for (int i = 0; i < npages; i++) {
struct mbuf *m0;
/*
* If a page wasn't grabbed successfully, then
* trim the array. Can happen only with SF_NODISKIO.
*/
if (pa[i] == NULL) {
SFSTAT_INC(sf_busy);
fixspace(npages, i, off, &space);
npages = i;
softerr = EBUSY;
break;
}
if (use_ext_pgs) {
off_t xfs;
ext_pgs_idx++;
if (ext_pgs_idx == max_pgs) {
m0 = mb_alloc_ext_pgs(M_WAITOK, false,
sendfile_free_mext_pg);
if (flags & SF_NOCACHE) {
m0->m_ext.ext_flags |=
EXT_FLAG_NOCACHE;
/*
* See comment below regarding
* ignoring SF_NOCACHE for the
* last page.
*/
if ((npages - i <= max_pgs) &&
((off + space) & PAGE_MASK) &&
(rem > space || rhpages > 0))
m0->m_ext.ext_flags |=
EXT_FLAG_CACHE_LAST;
}
if (sfs != NULL) {
m0->m_ext.ext_flags |=
EXT_FLAG_SYNC;
m0->m_ext.ext_arg2 = sfs;
mtx_lock(&sfs->mtx);
sfs->count++;
mtx_unlock(&sfs->mtx);
}
ext_pgs = m0->m_ext.ext_pgs;
if (i == 0)
sfio->m = m0;
ext_pgs_idx = 0;
/* Append to mbuf chain. */
if (mtail != NULL)
mtail->m_next = m0;
else
m = m0;
mtail = m0;
ext_pgs->first_pg_off =
vmoff(i, off) & PAGE_MASK;
}
if (nios) {
mtail->m_flags |= M_NOTREADY;
ext_pgs->nrdy++;
}
ext_pgs->pa[ext_pgs_idx] = VM_PAGE_TO_PHYS(pa[i]);
ext_pgs->npgs++;
xfs = xfsize(i, npages, off, space);
ext_pgs->last_pg_len = xfs;
MBUF_EXT_PGS_ASSERT_SANITY(ext_pgs);
mtail->m_len += xfs;
mtail->m_ext.ext_size += PAGE_SIZE;
continue;
}
/*
* Get a sendfile buf. When allocating the
* first buffer for mbuf chain, we usually
* wait as long as necessary, but this wait
* can be interrupted. For consequent
* buffers, do not sleep, since several
* threads might exhaust the buffers and then
* deadlock.
*/
sf = sf_buf_alloc(pa[i],
m != NULL ? SFB_NOWAIT : SFB_CATCH);
if (sf == NULL) {
SFSTAT_INC(sf_allocfail);
for (int j = i; j < npages; j++) {
vm_page_lock(pa[j]);
vm_page_unwire(pa[j], PQ_INACTIVE);
vm_page_unlock(pa[j]);
}
if (m == NULL)
softerr = ENOBUFS;
fixspace(npages, i, off, &space);
npages = i;
break;
}
m0 = m_get(M_WAITOK, MT_DATA);
m0->m_ext.ext_buf = (char *)sf_buf_kva(sf);
m0->m_ext.ext_size = PAGE_SIZE;
m0->m_ext.ext_arg1 = sf;
m0->m_ext.ext_type = EXT_SFBUF;
m0->m_ext.ext_flags = EXT_FLAG_EMBREF;
m0->m_ext.ext_free = sendfile_free_mext;
/*
* SF_NOCACHE sets the page as being freed upon send.
* However, we ignore it for the last page in 'space',
* if the page is truncated, and we got more data to
* send (rem > space), or if we have readahead
* configured (rhpages > 0).
*/
if ((flags & SF_NOCACHE) &&
(i != npages - 1 ||
!((off + space) & PAGE_MASK) ||
!(rem > space || rhpages > 0)))
m0->m_ext.ext_flags |= EXT_FLAG_NOCACHE;
if (sfs != NULL) {
m0->m_ext.ext_flags |= EXT_FLAG_SYNC;
m0->m_ext.ext_arg2 = sfs;
mtx_lock(&sfs->mtx);
sfs->count++;
mtx_unlock(&sfs->mtx);
}
m0->m_ext.ext_count = 1;
m0->m_flags |= (M_EXT | M_RDONLY);
if (nios)
m0->m_flags |= M_NOTREADY;
m0->m_data = (char *)sf_buf_kva(sf) +
(vmoff(i, off) & PAGE_MASK);
m0->m_len = xfsize(i, npages, off, space);
if (i == 0)
sfio->m = m0;
/* Append to mbuf chain. */
if (mtail != NULL)
mtail->m_next = m0;
else
m = m0;
mtail = m0;
}
if (vp != NULL)
VOP_UNLOCK(vp, 0);
/* Keep track of bytes processed. */
off += space;
rem -= space;
/* Prepend header, if any. */
if (hdrlen) {
prepend_header:
mhtail->m_next = m;
m = mh;
mh = NULL;
}
if (m == NULL) {
KASSERT(softerr, ("%s: m NULL, no error", __func__));
error = softerr;
free(sfio, M_TEMP);
goto done;
}
/* Add the buffer chain to the socket buffer. */
KASSERT(m_length(m, NULL) == space + hdrlen,
("%s: mlen %u space %d hdrlen %d",
__func__, m_length(m, NULL), space, hdrlen));
CURVNET_SET(so->so_vnet);
if (nios == 0) {
/*
* If sendfile_swapin() didn't initiate any I/Os,
* which happens if all data is cached in VM, then
* we can send data right now without the
* PRUS_NOTREADY flag.
*/
free(sfio, M_TEMP);
error = (*so->so_proto->pr_usrreqs->pru_send)
(so, 0, m, NULL, NULL, td);
} else {
sfio->npages = npages;
soref(so);
error = (*so->so_proto->pr_usrreqs->pru_send)
(so, PRUS_NOTREADY, m, NULL, NULL, td);
sendfile_iodone(sfio, NULL, 0, 0);
}
CURVNET_RESTORE();
m = NULL; /* pru_send always consumes */
if (error)
goto done;
sbytes += space + hdrlen;
if (hdrlen)
hdrlen = 0;
if (softerr) {
error = softerr;
goto done;
}
}
/*
* Send trailers. Wimp out and use writev(2).
*/
if (trl_uio != NULL) {
sbunlock(&so->so_snd);
error = kern_writev(td, sockfd, trl_uio);
if (error == 0)
sbytes += td->td_retval[0];
goto out;
}
done:
sbunlock(&so->so_snd);
out:
/*
* If there was no error we have to clear td->td_retval[0]
* because it may have been set by writev.
*/
if (error == 0) {
td->td_retval[0] = 0;
}
if (sent != NULL) {
(*sent) = sbytes;
}
if (obj != NULL)
vm_object_deallocate(obj);
if (so)
fdrop(sock_fp, td);
if (m)
m_freem(m);
if (mh)
m_freem(mh);
if (sfs != NULL) {
mtx_lock(&sfs->mtx);
if (sfs->count != 0)
cv_wait(&sfs->cv, &sfs->mtx);
KASSERT(sfs->count == 0, ("sendfile sync still busy"));
cv_destroy(&sfs->cv);
mtx_destroy(&sfs->mtx);
free(sfs, M_TEMP);
}
if (error == ERESTART)
error = EINTR;
return (error);
}
static int
sendfile(struct thread *td, struct sendfile_args *uap, int compat)
{
struct sf_hdtr hdtr;
struct uio *hdr_uio, *trl_uio;
struct file *fp;
off_t sbytes;
int error;
/*
* File offset must be positive. If it goes beyond EOF
* we send only the header/trailer and no payload data.
*/
if (uap->offset < 0)
return (EINVAL);
sbytes = 0;
hdr_uio = trl_uio = NULL;
if (uap->hdtr != NULL) {
error = copyin(uap->hdtr, &hdtr, sizeof(hdtr));
if (error != 0)
goto out;
if (hdtr.headers != NULL) {
error = copyinuio(hdtr.headers, hdtr.hdr_cnt,
&hdr_uio);
if (error != 0)
goto out;
#ifdef COMPAT_FREEBSD4
/*
* In FreeBSD < 5.0 the nbytes to send also included
* the header. If compat is specified subtract the
* header size from nbytes.
*/
if (compat) {
if (uap->nbytes > hdr_uio->uio_resid)
uap->nbytes -= hdr_uio->uio_resid;
else
uap->nbytes = 0;
}
#endif
}
if (hdtr.trailers != NULL) {
error = copyinuio(hdtr.trailers, hdtr.trl_cnt,
&trl_uio);
if (error != 0)
goto out;
}
}
AUDIT_ARG_FD(uap->fd);
/*
* sendfile(2) can start at any offset within a file so we require
* CAP_READ+CAP_SEEK = CAP_PREAD.
*/
if ((error = fget_read(td, uap->fd, &cap_pread_rights, &fp)) != 0)
goto out;
error = fo_sendfile(fp, uap->s, hdr_uio, trl_uio, uap->offset,
uap->nbytes, &sbytes, uap->flags, td);
fdrop(fp, td);
if (uap->sbytes != NULL)
copyout(&sbytes, uap->sbytes, sizeof(off_t));
out:
free(hdr_uio, M_IOV);
free(trl_uio, M_IOV);
return (error);
}
/*
* sendfile(2)
*
* int sendfile(int fd, int s, off_t offset, size_t nbytes,
* struct sf_hdtr *hdtr, off_t *sbytes, int flags)
*
* Send a file specified by 'fd' and starting at 'offset' to a socket
* specified by 's'. Send only 'nbytes' of the file or until EOF if nbytes ==
* 0. Optionally add a header and/or trailer to the socket output. If
* specified, write the total number of bytes sent into *sbytes.
*/
int
sys_sendfile(struct thread *td, struct sendfile_args *uap)
{
return (sendfile(td, uap, 0));
}
#ifdef COMPAT_FREEBSD4
int
freebsd4_sendfile(struct thread *td, struct freebsd4_sendfile_args *uap)
{
struct sendfile_args args;
args.fd = uap->fd;
args.s = uap->s;
args.offset = uap->offset;
args.nbytes = uap->nbytes;
args.hdtr = uap->hdtr;
args.sbytes = uap->sbytes;
args.flags = uap->flags;
return (sendfile(td, &args, 1));
}
#endif /* COMPAT_FREEBSD4 */
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