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74fb0ba732
freebsd-skq/sys/rpc/svc_vc.c
John Baldwin 74fb0ba732 Rework socket upcalls to close some races with setup/teardown of upcalls. 
- Each socket upcall is now invoked with the appropriate socket buffer
  locked.  It is not permissible to call soisconnected() with this lock
  held; however, so socket upcalls now return an integer value.  The two
  possible values are SU_OK and SU_ISCONNECTED.  If an upcall returns
  SU_ISCONNECTED, then the soisconnected() will be invoked on the
  socket after the socket buffer lock is dropped.
- A new API is provided for setting and clearing socket upcalls.  The
  API consists of soupcall_set() and soupcall_clear().
- To simplify locking, each socket buffer now has a separate upcall.
- When a socket upcall returns SU_ISCONNECTED, the upcall is cleared from
  the receive socket buffer automatically.  Note that a SO_SND upcall
  should never return SU_ISCONNECTED.
- All this means that accept filters should now return SU_ISCONNECTED
  instead of calling soisconnected() directly.  They also no longer need
  to explicitly clear the upcall on the new socket.
- The HTTP accept filter still uses soupcall_set() to manage its internal
  state machine, but other accept filters no longer have any explicit
  knowlege of socket upcall internals aside from their return value.
- The various RPC client upcalls currently drop the socket buffer lock
  while invoking soreceive() as a temporary band-aid.  The plan for
  the future is to add a new flag to allow soreceive() to be called with
  the socket buffer locked.
- The AIO callback for socket I/O is now also invoked with the socket
  buffer locked.  Previously sowakeup() would drop the socket buffer
  lock only to call aio_swake() which immediately re-acquired the socket
  buffer lock for the duration of the function call.

Discussed with:	rwatson, rmacklem
2009-06-01 21:17:03 +00:00

754 lines
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/* $NetBSD: svc_vc.c,v 1.7 2000/08/03 00:01:53 fvdl Exp $ */
/*
* Sun RPC is a product of Sun Microsystems, Inc. and is provided for
* unrestricted use provided that this legend is included on all tape
* media and as a part of the software program in whole or part. Users
* may copy or modify Sun RPC without charge, but are not authorized
* to license or distribute it to anyone else except as part of a product or
* program developed by the user.
*
* SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
* WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
* PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
*
* Sun RPC is provided with no support and without any obligation on the
* part of Sun Microsystems, Inc. to assist in its use, correction,
* modification or enhancement.
*
* SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
* INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
* OR ANY PART THEREOF.
*
* In no event will Sun Microsystems, Inc. be liable for any lost revenue
* or profits or other special, indirect and consequential damages, even if
* Sun has been advised of the possibility of such damages.
*
* Sun Microsystems, Inc.
* 2550 Garcia Avenue
* Mountain View, California 94043
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char *sccsid2 = "@(#)svc_tcp.c 1.21 87/08/11 Copyr 1984 Sun Micro";
static char *sccsid = "@(#)svc_tcp.c 2.2 88/08/01 4.0 RPCSRC";
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* svc_vc.c, Server side for Connection Oriented based RPC.
*
* Actually implements two flavors of transporter -
* a tcp rendezvouser (a listner and connection establisher)
* and a record/tcp stream.
*/
#include <sys/param.h>
#include <sys/lock.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/protosw.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sx.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <netinet/tcp.h>
#include <rpc/rpc.h>
#include <rpc/rpc_com.h>
static bool_t svc_vc_rendezvous_recv(SVCXPRT *, struct rpc_msg *,
struct sockaddr **, struct mbuf **);
static enum xprt_stat svc_vc_rendezvous_stat(SVCXPRT *);
static void svc_vc_rendezvous_destroy(SVCXPRT *);
static bool_t svc_vc_null(void);
static void svc_vc_destroy(SVCXPRT *);
static enum xprt_stat svc_vc_stat(SVCXPRT *);
static bool_t svc_vc_recv(SVCXPRT *, struct rpc_msg *,
struct sockaddr **, struct mbuf **);
static bool_t svc_vc_reply(SVCXPRT *, struct rpc_msg *,
struct sockaddr *, struct mbuf *);
static bool_t svc_vc_control(SVCXPRT *xprt, const u_int rq, void *in);
static bool_t svc_vc_rendezvous_control (SVCXPRT *xprt, const u_int rq,
void *in);
static SVCXPRT *svc_vc_create_conn(SVCPOOL *pool, struct socket *so,
struct sockaddr *raddr);
static int svc_vc_accept(struct socket *head, struct socket **sop);
static int svc_vc_soupcall(struct socket *so, void *arg, int waitflag);
static struct xp_ops svc_vc_rendezvous_ops = {
.xp_recv = svc_vc_rendezvous_recv,
.xp_stat = svc_vc_rendezvous_stat,
.xp_reply = (bool_t (*)(SVCXPRT *, struct rpc_msg *,
struct sockaddr *, struct mbuf *))svc_vc_null,
.xp_destroy = svc_vc_rendezvous_destroy,
.xp_control = svc_vc_rendezvous_control
};
static struct xp_ops svc_vc_ops = {
.xp_recv = svc_vc_recv,
.xp_stat = svc_vc_stat,
.xp_reply = svc_vc_reply,
.xp_destroy = svc_vc_destroy,
.xp_control = svc_vc_control
};
struct cf_conn { /* kept in xprt->xp_p1 for actual connection */
enum xprt_stat strm_stat;
struct mbuf *mpending; /* unparsed data read from the socket */
struct mbuf *mreq; /* current record being built from mpending */
uint32_t resid; /* number of bytes needed for fragment */
bool_t eor; /* reading last fragment of current record */
};
/*
* Usage:
* xprt = svc_vc_create(sock, send_buf_size, recv_buf_size);
*
* Creates, registers, and returns a (rpc) tcp based transporter.
* Once *xprt is initialized, it is registered as a transporter
* see (svc.h, xprt_register). This routine returns
* a NULL if a problem occurred.
*
* The filedescriptor passed in is expected to refer to a bound, but
* not yet connected socket.
*
* Since streams do buffered io similar to stdio, the caller can specify
* how big the send and receive buffers are via the second and third parms;
* 0 => use the system default.
*/
SVCXPRT *
svc_vc_create(SVCPOOL *pool, struct socket *so, size_t sendsize,
size_t recvsize)
{
SVCXPRT *xprt;
struct sockaddr* sa;
int error;
if (so->so_state & SS_ISCONNECTED) {
error = so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa);
if (error)
return (NULL);
xprt = svc_vc_create_conn(pool, so, sa);
free(sa, M_SONAME);
return (xprt);
}
xprt = svc_xprt_alloc();
sx_init(&xprt->xp_lock, "xprt->xp_lock");
xprt->xp_pool = pool;
xprt->xp_socket = so;
xprt->xp_p1 = NULL;
xprt->xp_p2 = NULL;
xprt->xp_ops = &svc_vc_rendezvous_ops;
error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
if (error)
goto cleanup_svc_vc_create;
memcpy(&xprt->xp_ltaddr, sa, sa->sa_len);
free(sa, M_SONAME);
xprt_register(xprt);
solisten(so, SOMAXCONN, curthread);
SOCKBUF_LOCK(&so->so_rcv);
soupcall_set(so, SO_RCV, svc_vc_soupcall, xprt);
SOCKBUF_UNLOCK(&so->so_rcv);
return (xprt);
cleanup_svc_vc_create:
if (xprt)
svc_xprt_free(xprt);
return (NULL);
}
/*
* Create a new transport for a socket optained via soaccept().
*/
SVCXPRT *
svc_vc_create_conn(SVCPOOL *pool, struct socket *so, struct sockaddr *raddr)
{
SVCXPRT *xprt = NULL;
struct cf_conn *cd = NULL;
struct sockaddr* sa = NULL;
struct sockopt opt;
int one = 1;
int error;
bzero(&opt, sizeof(struct sockopt));
opt.sopt_dir = SOPT_SET;
opt.sopt_level = SOL_SOCKET;
opt.sopt_name = SO_KEEPALIVE;
opt.sopt_val = &one;
opt.sopt_valsize = sizeof(one);
error = sosetopt(so, &opt);
if (error)
return (NULL);
if (so->so_proto->pr_protocol == IPPROTO_TCP) {
bzero(&opt, sizeof(struct sockopt));
opt.sopt_dir = SOPT_SET;
opt.sopt_level = IPPROTO_TCP;
opt.sopt_name = TCP_NODELAY;
opt.sopt_val = &one;
opt.sopt_valsize = sizeof(one);
error = sosetopt(so, &opt);
if (error)
return (NULL);
}
cd = mem_alloc(sizeof(*cd));
cd->strm_stat = XPRT_IDLE;
xprt = svc_xprt_alloc();
sx_init(&xprt->xp_lock, "xprt->xp_lock");
xprt->xp_pool = pool;
xprt->xp_socket = so;
xprt->xp_p1 = cd;
xprt->xp_p2 = NULL;
xprt->xp_ops = &svc_vc_ops;
/*
* See http://www.connectathon.org/talks96/nfstcp.pdf - client
* has a 5 minute timer, server has a 6 minute timer.
*/
xprt->xp_idletimeout = 6 * 60;
memcpy(&xprt->xp_rtaddr, raddr, raddr->sa_len);
error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
if (error)
goto cleanup_svc_vc_create;
memcpy(&xprt->xp_ltaddr, sa, sa->sa_len);
free(sa, M_SONAME);
xprt_register(xprt);
SOCKBUF_LOCK(&so->so_rcv);
soupcall_set(so, SO_RCV, svc_vc_soupcall, xprt);
SOCKBUF_UNLOCK(&so->so_rcv);
/*
* Throw the transport into the active list in case it already
* has some data buffered.
*/
sx_xlock(&xprt->xp_lock);
xprt_active(xprt);
sx_xunlock(&xprt->xp_lock);
return (xprt);
cleanup_svc_vc_create:
if (xprt) {
mem_free(xprt, sizeof(*xprt));
}
if (cd)
mem_free(cd, sizeof(*cd));
return (NULL);
}
/*
* This does all of the accept except the final call to soaccept. The
* caller will call soaccept after dropping its locks (soaccept may
* call malloc).
*/
int
svc_vc_accept(struct socket *head, struct socket **sop)
{
int error = 0;
struct socket *so;
if ((head->so_options & SO_ACCEPTCONN) == 0) {
error = EINVAL;
goto done;
}
#ifdef MAC
SOCK_LOCK(head);
error = mac_socket_check_accept(td->td_ucred, head);
SOCK_UNLOCK(head);
if (error != 0)
goto done;
#endif
ACCEPT_LOCK();
if (TAILQ_EMPTY(&head->so_comp)) {
ACCEPT_UNLOCK();
error = EWOULDBLOCK;
goto done;
}
so = TAILQ_FIRST(&head->so_comp);
KASSERT(!(so->so_qstate & SQ_INCOMP), ("svc_vc_accept: so SQ_INCOMP"));
KASSERT(so->so_qstate & SQ_COMP, ("svc_vc_accept: so not SQ_COMP"));
/*
* Before changing the flags on the socket, we have to bump the
* reference count. Otherwise, if the protocol calls sofree(),
* the socket will be released due to a zero refcount.
* XXX might not need soref() since this is simpler than kern_accept.
*/
SOCK_LOCK(so); /* soref() and so_state update */
soref(so); /* file descriptor reference */
TAILQ_REMOVE(&head->so_comp, so, so_list);
head->so_qlen--;
so->so_state |= (head->so_state & SS_NBIO);
so->so_qstate &= ~SQ_COMP;
so->so_head = NULL;
SOCK_UNLOCK(so);
ACCEPT_UNLOCK();
*sop = so;
/* connection has been removed from the listen queue */
KNOTE_UNLOCKED(&head->so_rcv.sb_sel.si_note, 0);
done:
return (error);
}
/*ARGSUSED*/
static bool_t
svc_vc_rendezvous_recv(SVCXPRT *xprt, struct rpc_msg *msg,
struct sockaddr **addrp, struct mbuf **mp)
{
struct socket *so = NULL;
struct sockaddr *sa = NULL;
int error;
/*
* The socket upcall calls xprt_active() which will eventually
* cause the server to call us here. We attempt to accept a
* connection from the socket and turn it into a new
* transport. If the accept fails, we have drained all pending
* connections so we call xprt_inactive().
*/
sx_xlock(&xprt->xp_lock);
error = svc_vc_accept(xprt->xp_socket, &so);
if (error == EWOULDBLOCK) {
/*
* We must re-test for new connections after taking
* the lock to protect us in the case where a new
* connection arrives after our call to accept fails
* with EWOULDBLOCK. The pool lock protects us from
* racing the upcall after our TAILQ_EMPTY() call
* returns false.
*/
ACCEPT_LOCK();
mtx_lock(&xprt->xp_pool->sp_lock);
if (TAILQ_EMPTY(&xprt->xp_socket->so_comp))
xprt_inactive_locked(xprt);
mtx_unlock(&xprt->xp_pool->sp_lock);
ACCEPT_UNLOCK();
sx_xunlock(&xprt->xp_lock);
return (FALSE);
}
if (error) {
SOCKBUF_LOCK(&xprt->xp_socket->so_rcv);
soupcall_clear(xprt->xp_socket, SO_RCV);
SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
xprt_inactive(xprt);
sx_xunlock(&xprt->xp_lock);
return (FALSE);
}
sx_xunlock(&xprt->xp_lock);
sa = 0;
error = soaccept(so, &sa);
if (error) {
/*
* XXX not sure if I need to call sofree or soclose here.
*/
if (sa)
free(sa, M_SONAME);
return (FALSE);
}
/*
* svc_vc_create_conn will call xprt_register - we don't need
* to do anything with the new connection.
*/
if (!svc_vc_create_conn(xprt->xp_pool, so, sa))
soclose(so);
free(sa, M_SONAME);
return (FALSE); /* there is never an rpc msg to be processed */
}
/*ARGSUSED*/
static enum xprt_stat
svc_vc_rendezvous_stat(SVCXPRT *xprt)
{
return (XPRT_IDLE);
}
static void
svc_vc_destroy_common(SVCXPRT *xprt)
{
SOCKBUF_LOCK(&xprt->xp_socket->so_rcv);
soupcall_clear(xprt->xp_socket, SO_RCV);
SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
sx_destroy(&xprt->xp_lock);
if (xprt->xp_socket)
(void)soclose(xprt->xp_socket);
if (xprt->xp_netid)
(void) mem_free(xprt->xp_netid, strlen(xprt->xp_netid) + 1);
svc_xprt_free(xprt);
}
static void
svc_vc_rendezvous_destroy(SVCXPRT *xprt)
{
svc_vc_destroy_common(xprt);
}
static void
svc_vc_destroy(SVCXPRT *xprt)
{
struct cf_conn *cd = (struct cf_conn *)xprt->xp_p1;
svc_vc_destroy_common(xprt);
if (cd->mreq)
m_freem(cd->mreq);
if (cd->mpending)
m_freem(cd->mpending);
mem_free(cd, sizeof(*cd));
}
/*ARGSUSED*/
static bool_t
svc_vc_control(SVCXPRT *xprt, const u_int rq, void *in)
{
return (FALSE);
}
static bool_t
svc_vc_rendezvous_control(SVCXPRT *xprt, const u_int rq, void *in)
{
return (FALSE);
}
static enum xprt_stat
svc_vc_stat(SVCXPRT *xprt)
{
struct cf_conn *cd;
struct mbuf *m;
size_t n;
cd = (struct cf_conn *)(xprt->xp_p1);
if (cd->strm_stat == XPRT_DIED)
return (XPRT_DIED);
/*
* Return XPRT_MOREREQS if we have buffered data and we are
* mid-record or if we have enough data for a record
* marker. Since this is only a hint, we read mpending and
* resid outside the lock. We do need to take the lock if we
* have to traverse the mbuf chain.
*/
if (cd->mpending) {
if (cd->resid)
return (XPRT_MOREREQS);
n = 0;
sx_xlock(&xprt->xp_lock);
m = cd->mpending;
while (m && n < sizeof(uint32_t)) {
n += m->m_len;
m = m->m_next;
}
sx_xunlock(&xprt->xp_lock);
if (n >= sizeof(uint32_t))
return (XPRT_MOREREQS);
}
if (soreadable(xprt->xp_socket))
return (XPRT_MOREREQS);
return (XPRT_IDLE);
}
static bool_t
svc_vc_recv(SVCXPRT *xprt, struct rpc_msg *msg,
struct sockaddr **addrp, struct mbuf **mp)
{
struct cf_conn *cd = (struct cf_conn *) xprt->xp_p1;
struct uio uio;
struct mbuf *m;
XDR xdrs;
int error, rcvflag;
/*
* Serialise access to the socket and our own record parsing
* state.
*/
sx_xlock(&xprt->xp_lock);
for (;;) {
/*
* If we have an mbuf chain in cd->mpending, try to parse a
* record from it, leaving the result in cd->mreq. If we don't
* have a complete record, leave the partial result in
* cd->mreq and try to read more from the socket.
*/
if (cd->mpending) {
/*
* If cd->resid is non-zero, we have part of the
* record already, otherwise we are expecting a record
* marker.
*/
if (!cd->resid) {
/*
* See if there is enough data buffered to
* make up a record marker. Make sure we can
* handle the case where the record marker is
* split across more than one mbuf.
*/
size_t n = 0;
uint32_t header;
m = cd->mpending;
while (n < sizeof(uint32_t) && m) {
n += m->m_len;
m = m->m_next;
}
if (n < sizeof(uint32_t))
goto readmore;
if (cd->mpending->m_len < sizeof(uint32_t))
cd->mpending = m_pullup(cd->mpending,
sizeof(uint32_t));
memcpy(&header, mtod(cd->mpending, uint32_t *),
sizeof(header));
header = ntohl(header);
cd->eor = (header & 0x80000000) != 0;
cd->resid = header & 0x7fffffff;
m_adj(cd->mpending, sizeof(uint32_t));
}
/*
* Start pulling off mbufs from cd->mpending
* until we either have a complete record or
* we run out of data. We use m_split to pull
* data - it will pull as much as possible and
* split the last mbuf if necessary.
*/
while (cd->mpending && cd->resid) {
m = cd->mpending;
if (cd->mpending->m_next
|| cd->mpending->m_len > cd->resid)
cd->mpending = m_split(cd->mpending,
cd->resid, M_WAIT);
else
cd->mpending = NULL;
if (cd->mreq)
m_last(cd->mreq)->m_next = m;
else
cd->mreq = m;
while (m) {
cd->resid -= m->m_len;
m = m->m_next;
}
}
/*
* If cd->resid is zero now, we have managed to
* receive a record fragment from the stream. Check
* for the end-of-record mark to see if we need more.
*/
if (cd->resid == 0) {
if (!cd->eor)
continue;
/*
* Success - we have a complete record in
* cd->mreq.
*/
xdrmbuf_create(&xdrs, cd->mreq, XDR_DECODE);
cd->mreq = NULL;
sx_xunlock(&xprt->xp_lock);
if (! xdr_callmsg(&xdrs, msg)) {
XDR_DESTROY(&xdrs);
return (FALSE);
}
*addrp = NULL;
*mp = xdrmbuf_getall(&xdrs);
XDR_DESTROY(&xdrs);
return (TRUE);
}
}
readmore:
/*
* The socket upcall calls xprt_active() which will eventually
* cause the server to call us here. We attempt to
* read as much as possible from the socket and put
* the result in cd->mpending. If the read fails,
* we have drained both cd->mpending and the socket so
* we can call xprt_inactive().
*/
uio.uio_resid = 1000000000;
uio.uio_td = curthread;
m = NULL;
rcvflag = MSG_DONTWAIT;
error = soreceive(xprt->xp_socket, NULL, &uio, &m, NULL,
&rcvflag);
if (error == EWOULDBLOCK) {
/*
* We must re-test for readability after
* taking the lock to protect us in the case
* where a new packet arrives on the socket
* after our call to soreceive fails with
* EWOULDBLOCK. The pool lock protects us from
* racing the upcall after our soreadable()
* call returns false.
*/
mtx_lock(&xprt->xp_pool->sp_lock);
if (!soreadable(xprt->xp_socket))
xprt_inactive_locked(xprt);
mtx_unlock(&xprt->xp_pool->sp_lock);
sx_xunlock(&xprt->xp_lock);
return (FALSE);
}
if (error) {
SOCKBUF_LOCK(&xprt->xp_socket->so_rcv);
soupcall_clear(xprt->xp_socket, SO_RCV);
SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv);
xprt_inactive(xprt);
cd->strm_stat = XPRT_DIED;
sx_xunlock(&xprt->xp_lock);
return (FALSE);
}
if (!m) {
/*
* EOF - the other end has closed the socket.
*/
xprt_inactive(xprt);
cd->strm_stat = XPRT_DIED;
sx_xunlock(&xprt->xp_lock);
return (FALSE);
}
if (cd->mpending)
m_last(cd->mpending)->m_next = m;
else
cd->mpending = m;
}
}
static bool_t
svc_vc_reply(SVCXPRT *xprt, struct rpc_msg *msg,
struct sockaddr *addr, struct mbuf *m)
{
XDR xdrs;
struct mbuf *mrep;
bool_t stat = TRUE;
int error;
/*
* Leave space for record mark.
*/
MGETHDR(mrep, M_WAIT, MT_DATA);
mrep->m_len = 0;
mrep->m_data += sizeof(uint32_t);
xdrmbuf_create(&xdrs, mrep, XDR_ENCODE);
if (msg->rm_reply.rp_stat == MSG_ACCEPTED &&
msg->rm_reply.rp_acpt.ar_stat == SUCCESS) {
if (!xdr_replymsg(&xdrs, msg))
stat = FALSE;
else
xdrmbuf_append(&xdrs, m);
} else {
stat = xdr_replymsg(&xdrs, msg);
}
if (stat) {
m_fixhdr(mrep);
/*
* Prepend a record marker containing the reply length.
*/
M_PREPEND(mrep, sizeof(uint32_t), M_WAIT);
*mtod(mrep, uint32_t *) =
htonl(0x80000000 | (mrep->m_pkthdr.len
- sizeof(uint32_t)));
error = sosend(xprt->xp_socket, NULL, NULL, mrep, NULL,
0, curthread);
if (!error) {
stat = TRUE;
}
} else {
m_freem(mrep);
}
XDR_DESTROY(&xdrs);
xprt->xp_p2 = NULL;
return (stat);
}
static bool_t
svc_vc_null()
{
return (FALSE);
}
static int
svc_vc_soupcall(struct socket *so, void *arg, int waitflag)
{
SVCXPRT *xprt = (SVCXPRT *) arg;
xprt_active(xprt);
return (SU_OK);
}
#if 0
/*
* Get the effective UID of the sending process. Used by rpcbind, keyserv
* and rpc.yppasswdd on AF_LOCAL.
*/
int
__rpc_get_local_uid(SVCXPRT *transp, uid_t *uid) {
int sock, ret;
gid_t egid;
uid_t euid;
struct sockaddr *sa;
sock = transp->xp_fd;
sa = (struct sockaddr *)transp->xp_rtaddr;
if (sa->sa_family == AF_LOCAL) {
ret = getpeereid(sock, &euid, &egid);
if (ret == 0)
*uid = euid;
return (ret);
} else
return (-1);
}
#endif
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