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freebsd-nq/sys/kern/uipc_usrreq.c

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/*-
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California.
* Copyright 2004-2005 Robert N. M. Watson
* 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.
* 4. 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.
*
* From: @(#)uipc_usrreq.c 8.3 (Berkeley) 1/4/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/domain.h>
#include <sys/fcntl.h>
#include <sys/malloc.h> /* XXX must be before <sys/file.h> */
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mac.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/resourcevar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/signalvar.h>
#include <sys/stat.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/taskqueue.h>
#include <sys/un.h>
#include <sys/unpcb.h>
#include <sys/vnode.h>
#include <vm/uma.h>
static uma_zone_t unp_zone;
static unp_gen_t unp_gencnt;
static u_int unp_count;
static struct unp_head unp_shead, unp_dhead;
/*
* Unix communications domain.
*
* TODO:
* SEQPACKET, RDM
* rethink name space problems
* need a proper out-of-band
* lock pushdown
*/
static const struct sockaddr sun_noname = { sizeof(sun_noname), AF_LOCAL };
static ino_t unp_ino; /* prototype for fake inode numbers */
struct mbuf *unp_addsockcred(struct thread *, struct mbuf *);
/*
* Currently, UNIX domain sockets are protected by a single subsystem lock,
* which covers global data structures and variables, the contents of each
* per-socket unpcb structure, and the so_pcb field in sockets attached to
* the UNIX domain. This provides for a moderate degree of paralellism, as
* receive operations on UNIX domain sockets do not need to acquire the
* subsystem lock. Finer grained locking to permit send() without acquiring
* a global lock would be a logical next step.
*
* The UNIX domain socket lock preceds all socket layer locks, including the
* socket lock and socket buffer lock, permitting UNIX domain socket code to
* call into socket support routines without releasing its locks.
*
* Some caution is required in areas where the UNIX domain socket code enters
* VFS in order to create or find rendezvous points. This results in
* dropping of the UNIX domain socket subsystem lock, acquisition of the
* Giant lock, and potential sleeping. This increases the chances of races,
* and exposes weaknesses in the socket->protocol API by offering poor
* failure modes.
*/
static struct mtx unp_mtx;
#define UNP_LOCK_INIT() \
mtx_init(&unp_mtx, "unp", NULL, MTX_DEF)
#define UNP_LOCK() mtx_lock(&unp_mtx)
#define UNP_UNLOCK() mtx_unlock(&unp_mtx)
#define UNP_LOCK_ASSERT() mtx_assert(&unp_mtx, MA_OWNED)
#define UNP_UNLOCK_ASSERT() mtx_assert(&unp_mtx, MA_NOTOWNED)
/*
* Garbage collection of cyclic file descriptor/socket references occurs
* asynchronously in a taskqueue context in order to avoid recursion and
* reentrance in the UNIX domain socket, file descriptor, and socket layer
* code. See unp_gc() for a full description.
*/
static struct task unp_gc_task;
static int unp_attach(struct socket *);
static void unp_detach(struct unpcb *);
static int unp_bind(struct unpcb *,struct sockaddr *, struct thread *);
static int unp_connect(struct socket *,struct sockaddr *, struct thread *);
static int unp_connect2(struct socket *so, struct socket *so2, int);
static void unp_disconnect(struct unpcb *);
static void unp_shutdown(struct unpcb *);
static void unp_drop(struct unpcb *, int);
static void unp_gc(__unused void *, int);
static void unp_scan(struct mbuf *, void (*)(struct file *));
static void unp_mark(struct file *);
static void unp_discard(struct file *);
static void unp_freerights(struct file **, int);
static int unp_internalize(struct mbuf **, struct thread *);
static int unp_listen(struct socket *, struct unpcb *, int,
struct thread *);
static int
uipc_abort(struct socket *so)
{
struct unpcb *unp;
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
UNP_UNLOCK();
return (EINVAL);
}
unp_drop(unp, ECONNABORTED);
unp_detach(unp);
UNP_UNLOCK_ASSERT();
ACCEPT_LOCK();
SOCK_LOCK(so);
sotryfree(so);
return (0);
}
static int
uipc_accept(struct socket *so, struct sockaddr **nam)
{
struct unpcb *unp;
const struct sockaddr *sa;
/*
* Pass back name of connected socket,
* if it was bound and we are still connected
* (our peer may have closed already!).
*/
*nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
UNP_UNLOCK();
free(*nam, M_SONAME);
*nam = NULL;
return (EINVAL);
}
if (unp->unp_conn != NULL && unp->unp_conn->unp_addr != NULL)
sa = (struct sockaddr *) unp->unp_conn->unp_addr;
else
sa = &sun_noname;
bcopy(sa, *nam, sa->sa_len);
UNP_UNLOCK();
return (0);
}
static int
uipc_attach(struct socket *so, int proto, struct thread *td)
{
struct unpcb *unp = sotounpcb(so);
if (unp != NULL)
return (EISCONN);
return (unp_attach(so));
}
static int
uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
{
struct unpcb *unp;
int error;
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
UNP_UNLOCK();
return (EINVAL);
}
error = unp_bind(unp, nam, td);
UNP_UNLOCK();
return (error);
}
static int
uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
{
struct unpcb *unp;
int error;
KASSERT(td == curthread, ("uipc_connect: td != curthread"));
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
UNP_UNLOCK();
return (EINVAL);
}
error = unp_connect(so, nam, td);
UNP_UNLOCK();
return (error);
}
int
uipc_connect2(struct socket *so1, struct socket *so2)
{
struct unpcb *unp;
int error;
UNP_LOCK();
unp = sotounpcb(so1);
if (unp == NULL) {
UNP_UNLOCK();
return (EINVAL);
}
error = unp_connect2(so1, so2, PRU_CONNECT2);
UNP_UNLOCK();
return (error);
}
/* control is EOPNOTSUPP */
static int
uipc_detach(struct socket *so)
{
struct unpcb *unp;
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
UNP_UNLOCK();
return (EINVAL);
}
unp_detach(unp);
UNP_UNLOCK_ASSERT();
return (0);
}
static int
uipc_disconnect(struct socket *so)
{
struct unpcb *unp;
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
UNP_UNLOCK();
return (EINVAL);
}
unp_disconnect(unp);
UNP_UNLOCK();
return (0);
}
static int
uipc_listen(struct socket *so, int backlog, struct thread *td)
{
struct unpcb *unp;
int error;
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL || unp->unp_vnode == NULL) {
UNP_UNLOCK();
return (EINVAL);
}
error = unp_listen(so, unp, backlog, td);
UNP_UNLOCK();
return (error);
}
static int
uipc_peeraddr(struct socket *so, struct sockaddr **nam)
{
struct unpcb *unp;
const struct sockaddr *sa;
*nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
UNP_UNLOCK();
free(*nam, M_SONAME);
*nam = NULL;
return (EINVAL);
}
if (unp->unp_conn != NULL && unp->unp_conn->unp_addr!= NULL)
sa = (struct sockaddr *) unp->unp_conn->unp_addr;
else {
/*
* XXX: It seems that this test always fails even when
* connection is established. So, this else clause is
* added as workaround to return PF_LOCAL sockaddr.
*/
sa = &sun_noname;
}
bcopy(sa, *nam, sa->sa_len);
UNP_UNLOCK();
return (0);
}
static int
uipc_rcvd(struct socket *so, int flags)
{
struct unpcb *unp;
struct socket *so2;
u_long newhiwat;
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
UNP_UNLOCK();
return (EINVAL);
}
switch (so->so_type) {
case SOCK_DGRAM:
panic("uipc_rcvd DGRAM?");
/*NOTREACHED*/
case SOCK_STREAM:
if (unp->unp_conn == NULL)
break;
so2 = unp->unp_conn->unp_socket;
SOCKBUF_LOCK(&so2->so_snd);
SOCKBUF_LOCK(&so->so_rcv);
/*
* Adjust backpressure on sender
* and wakeup any waiting to write.
*/
so2->so_snd.sb_mbmax += unp->unp_mbcnt - so->so_rcv.sb_mbcnt;
unp->unp_mbcnt = so->so_rcv.sb_mbcnt;
newhiwat = so2->so_snd.sb_hiwat + unp->unp_cc -
so->so_rcv.sb_cc;
(void)chgsbsize(so2->so_cred->cr_uidinfo, &so2->so_snd.sb_hiwat,
newhiwat, RLIM_INFINITY);
unp->unp_cc = so->so_rcv.sb_cc;
SOCKBUF_UNLOCK(&so->so_rcv);
sowwakeup_locked(so2);
break;
default:
panic("uipc_rcvd unknown socktype");
}
UNP_UNLOCK();
return (0);
}
/* pru_rcvoob is EOPNOTSUPP */
static int
uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
struct mbuf *control, struct thread *td)
{
int error = 0;
struct unpcb *unp;
struct socket *so2;
u_long newhiwat;
unp = sotounpcb(so);
if (unp == NULL) {
error = EINVAL;
goto release;
}
if (flags & PRUS_OOB) {
error = EOPNOTSUPP;
goto release;
}
if (control != NULL && (error = unp_internalize(&control, td)))
goto release;
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
UNP_UNLOCK();
error = EINVAL;
goto dispose_release;
}
switch (so->so_type) {
case SOCK_DGRAM:
{
const struct sockaddr *from;
if (nam != NULL) {
if (unp->unp_conn != NULL) {
error = EISCONN;
break;
}
error = unp_connect(so, nam, td);
if (error)
break;
} else {
if (unp->unp_conn == NULL) {
error = ENOTCONN;
break;
}
}
so2 = unp->unp_conn->unp_socket;
if (unp->unp_addr != NULL)
from = (struct sockaddr *)unp->unp_addr;
else
from = &sun_noname;
if (unp->unp_conn->unp_flags & UNP_WANTCRED)
control = unp_addsockcred(td, control);
SOCKBUF_LOCK(&so2->so_rcv);
if (sbappendaddr_locked(&so2->so_rcv, from, m, control)) {
sorwakeup_locked(so2);
m = NULL;
control = NULL;
} else {
SOCKBUF_UNLOCK(&so2->so_rcv);
error = ENOBUFS;
}
if (nam != NULL)
unp_disconnect(unp);
break;
}
case SOCK_STREAM:
/* Connect if not connected yet. */
/*
* Note: A better implementation would complain
* if not equal to the peer's address.
*/
if ((so->so_state & SS_ISCONNECTED) == 0) {
if (nam != NULL) {
error = unp_connect(so, nam, td);
if (error)
break; /* XXX */
} else {
error = ENOTCONN;
break;
}
}
SOCKBUF_LOCK(&so->so_snd);
if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
SOCKBUF_UNLOCK(&so->so_snd);
error = EPIPE;
break;
}
if (unp->unp_conn == NULL)
panic("uipc_send connected but no connection?");
so2 = unp->unp_conn->unp_socket;
SOCKBUF_LOCK(&so2->so_rcv);
if (unp->unp_conn->unp_flags & UNP_WANTCRED) {
/*
* Credentials are passed only once on
* SOCK_STREAM.
*/
unp->unp_conn->unp_flags &= ~UNP_WANTCRED;
control = unp_addsockcred(td, control);
}
/*
* Send to paired receive port, and then reduce
* send buffer hiwater marks to maintain backpressure.
* Wake up readers.
*/
if (control != NULL) {
if (sbappendcontrol_locked(&so2->so_rcv, m, control))
control = NULL;
} else {
sbappend_locked(&so2->so_rcv, m);
}
so->so_snd.sb_mbmax -=
so2->so_rcv.sb_mbcnt - unp->unp_conn->unp_mbcnt;
unp->unp_conn->unp_mbcnt = so2->so_rcv.sb_mbcnt;
newhiwat = so->so_snd.sb_hiwat -
(so2->so_rcv.sb_cc - unp->unp_conn->unp_cc);
(void)chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.sb_hiwat,
newhiwat, RLIM_INFINITY);
SOCKBUF_UNLOCK(&so->so_snd);
unp->unp_conn->unp_cc = so2->so_rcv.sb_cc;
sorwakeup_locked(so2);
m = NULL;
break;
default:
panic("uipc_send unknown socktype");
}
/*
* SEND_EOF is equivalent to a SEND followed by
* a SHUTDOWN.
*/
if (flags & PRUS_EOF) {
socantsendmore(so);
unp_shutdown(unp);
}
UNP_UNLOCK();
dispose_release:
if (control != NULL && error != 0)
unp_dispose(control);
release:
if (control != NULL)
m_freem(control);
if (m != NULL)
m_freem(m);
return (error);
}
static int
uipc_sense(struct socket *so, struct stat *sb)
{
struct unpcb *unp;
struct socket *so2;
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
UNP_UNLOCK();
return (EINVAL);
}
sb->st_blksize = so->so_snd.sb_hiwat;
if (so->so_type == SOCK_STREAM && unp->unp_conn != NULL) {
so2 = unp->unp_conn->unp_socket;
sb->st_blksize += so2->so_rcv.sb_cc;
}
sb->st_dev = NODEV;
if (unp->unp_ino == 0)
unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino;
sb->st_ino = unp->unp_ino;
UNP_UNLOCK();
return (0);
}
static int
uipc_shutdown(struct socket *so)
{
struct unpcb *unp;
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
UNP_UNLOCK();
return (EINVAL);
}
socantsendmore(so);
unp_shutdown(unp);
UNP_UNLOCK();
return (0);
}
static int
uipc_sockaddr(struct socket *so, struct sockaddr **nam)
{
struct unpcb *unp;
const struct sockaddr *sa;
*nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
UNP_UNLOCK();
free(*nam, M_SONAME);
*nam = NULL;
return (EINVAL);
}
if (unp->unp_addr != NULL)
sa = (struct sockaddr *) unp->unp_addr;
else
sa = &sun_noname;
bcopy(sa, *nam, sa->sa_len);
UNP_UNLOCK();
return (0);
}
struct pr_usrreqs uipc_usrreqs = {
.pru_abort = uipc_abort,
.pru_accept = uipc_accept,
.pru_attach = uipc_attach,
.pru_bind = uipc_bind,
.pru_connect = uipc_connect,
.pru_connect2 = uipc_connect2,
.pru_detach = uipc_detach,
.pru_disconnect = uipc_disconnect,
.pru_listen = uipc_listen,
.pru_peeraddr = uipc_peeraddr,
.pru_rcvd = uipc_rcvd,
.pru_send = uipc_send,
.pru_sense = uipc_sense,
.pru_shutdown = uipc_shutdown,
.pru_sockaddr = uipc_sockaddr,
.pru_sosend = sosend,
.pru_soreceive = soreceive,
.pru_sopoll = sopoll,
};
int
uipc_ctloutput(struct socket *so, struct sockopt *sopt)
{
struct unpcb *unp;
struct xucred xu;
int error, optval;
if (sopt->sopt_level != 0)
return (EINVAL);
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
UNP_UNLOCK();
return (EINVAL);
}
error = 0;
switch (sopt->sopt_dir) {
case SOPT_GET:
switch (sopt->sopt_name) {
case LOCAL_PEERCRED:
if (unp->unp_flags & UNP_HAVEPC)
xu = unp->unp_peercred;
else {
if (so->so_type == SOCK_STREAM)
error = ENOTCONN;
else
error = EINVAL;
}
if (error == 0)
error = sooptcopyout(sopt, &xu, sizeof(xu));
break;
case LOCAL_CREDS:
optval = unp->unp_flags & UNP_WANTCRED ? 1 : 0;
error = sooptcopyout(sopt, &optval, sizeof(optval));
break;
case LOCAL_CONNWAIT:
optval = unp->unp_flags & UNP_CONNWAIT ? 1 : 0;
error = sooptcopyout(sopt, &optval, sizeof(optval));
break;
default:
error = EOPNOTSUPP;
break;
}
break;
case SOPT_SET:
switch (sopt->sopt_name) {
case LOCAL_CREDS:
case LOCAL_CONNWAIT:
error = sooptcopyin(sopt, &optval, sizeof(optval),
sizeof(optval));
if (error)
break;
#define OPTSET(bit) \
if (optval) \
unp->unp_flags |= bit; \
else \
unp->unp_flags &= ~bit;
switch (sopt->sopt_name) {
case LOCAL_CREDS:
OPTSET(UNP_WANTCRED);
break;
case LOCAL_CONNWAIT:
OPTSET(UNP_CONNWAIT);
break;
default:
break;
}
break;
#undef OPTSET
default:
error = ENOPROTOOPT;
break;
}
break;
default:
error = EOPNOTSUPP;
break;
}
UNP_UNLOCK();
return (error);
}
/*
* Both send and receive buffers are allocated PIPSIZ bytes of buffering
* for stream sockets, although the total for sender and receiver is
* actually only PIPSIZ.
* Datagram sockets really use the sendspace as the maximum datagram size,
* and don't really want to reserve the sendspace. Their recvspace should
* be large enough for at least one max-size datagram plus address.
*/
#ifndef PIPSIZ
#define PIPSIZ 8192
#endif
static u_long unpst_sendspace = PIPSIZ;
static u_long unpst_recvspace = PIPSIZ;
static u_long unpdg_sendspace = 2*1024; /* really max datagram size */
static u_long unpdg_recvspace = 4*1024;
static int unp_rights; /* file descriptors in flight */
SYSCTL_DECL(_net_local_stream);
SYSCTL_ULONG(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW,
&unpst_sendspace, 0, "");
SYSCTL_ULONG(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW,
&unpst_recvspace, 0, "");
SYSCTL_DECL(_net_local_dgram);
SYSCTL_ULONG(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW,
&unpdg_sendspace, 0, "");
SYSCTL_ULONG(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW,
&unpdg_recvspace, 0, "");
SYSCTL_DECL(_net_local);
SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, "");
static int
unp_attach(struct socket *so)
{
struct unpcb *unp;
int error;
if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
switch (so->so_type) {
case SOCK_STREAM:
error = soreserve(so, unpst_sendspace, unpst_recvspace);
break;
case SOCK_DGRAM:
error = soreserve(so, unpdg_sendspace, unpdg_recvspace);
break;
default:
panic("unp_attach");
}
if (error)
return (error);
}
unp = uma_zalloc(unp_zone, M_WAITOK | M_ZERO);
if (unp == NULL)
return (ENOBUFS);
LIST_INIT(&unp->unp_refs);
unp->unp_socket = so;
so->so_pcb = unp;
UNP_LOCK();
unp->unp_gencnt = ++unp_gencnt;
unp_count++;
LIST_INSERT_HEAD(so->so_type == SOCK_DGRAM ? &unp_dhead
: &unp_shead, unp, unp_link);
UNP_UNLOCK();
return (0);
}
static void
unp_detach(struct unpcb *unp)
{
struct vnode *vp;
int local_unp_rights;
UNP_LOCK_ASSERT();
LIST_REMOVE(unp, unp_link);
unp->unp_gencnt = ++unp_gencnt;
--unp_count;
if ((vp = unp->unp_vnode) != NULL) {
/*
* XXXRW: should v_socket be frobbed only while holding
* Giant?
*/
unp->unp_vnode->v_socket = NULL;
unp->unp_vnode = NULL;
}
if (unp->unp_conn != NULL)
unp_disconnect(unp);
while (!LIST_EMPTY(&unp->unp_refs)) {
struct unpcb *ref = LIST_FIRST(&unp->unp_refs);
unp_drop(ref, ECONNRESET);
}
soisdisconnected(unp->unp_socket);
unp->unp_socket->so_pcb = NULL;
local_unp_rights = unp_rights;
UNP_UNLOCK();
if (unp->unp_addr != NULL)
FREE(unp->unp_addr, M_SONAME);
uma_zfree(unp_zone, unp);
if (vp) {
mtx_lock(&Giant);
vrele(vp);
mtx_unlock(&Giant);
}
if (local_unp_rights)
taskqueue_enqueue(taskqueue_thread, &unp_gc_task);
}
static int
unp_bind(struct unpcb *unp, struct sockaddr *nam, struct thread *td)
{
struct sockaddr_un *soun = (struct sockaddr_un *)nam;
struct vnode *vp;
struct mount *mp;
struct vattr vattr;
int error, namelen;
struct nameidata nd;
char *buf;
UNP_LOCK_ASSERT();
/*
* XXXRW: This test-and-set of unp_vnode is non-atomic; the
* unlocked read here is fine, but the value of unp_vnode needs
* to be tested again after we do all the lookups to see if the
* pcb is still unbound?
*/
if (unp->unp_vnode != NULL)
return (EINVAL);
namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path);
if (namelen <= 0)
return (EINVAL);
UNP_UNLOCK();
buf = malloc(namelen + 1, M_TEMP, M_WAITOK);
strlcpy(buf, soun->sun_path, namelen + 1);
mtx_lock(&Giant);
restart:
mtx_assert(&Giant, MA_OWNED);
NDINIT(&nd, CREATE, NOFOLLOW | LOCKPARENT | SAVENAME, UIO_SYSSPACE,
buf, td);
/* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */
error = namei(&nd);
if (error)
goto done;
vp = nd.ni_vp;
if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) {
NDFREE(&nd, NDF_ONLY_PNBUF);
if (nd.ni_dvp == vp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
if (vp != NULL) {
vrele(vp);
error = EADDRINUSE;
goto done;
}
error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH);
if (error)
goto done;
goto restart;
}
VATTR_NULL(&vattr);
vattr.va_type = VSOCK;
vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask);
#ifdef MAC
error = mac_check_vnode_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd,
&vattr);
#endif
if (error == 0) {
VOP_LEASE(nd.ni_dvp, td, td->td_ucred, LEASE_WRITE);
error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
}
NDFREE(&nd, NDF_ONLY_PNBUF);
vput(nd.ni_dvp);
if (error) {
vn_finished_write(mp);
goto done;
}
vp = nd.ni_vp;
ASSERT_VOP_LOCKED(vp, "unp_bind");
soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK);
UNP_LOCK();
vp->v_socket = unp->unp_socket;
unp->unp_vnode = vp;
unp->unp_addr = soun;
UNP_UNLOCK();
VOP_UNLOCK(vp, 0, td);
vn_finished_write(mp);
done:
mtx_unlock(&Giant);
free(buf, M_TEMP);
UNP_LOCK();
return (error);
}
static int
unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
{
struct sockaddr_un *soun = (struct sockaddr_un *)nam;
struct vnode *vp;
struct socket *so2, *so3;
struct unpcb *unp, *unp2, *unp3;
int error, len;
struct nameidata nd;
char buf[SOCK_MAXADDRLEN];
struct sockaddr *sa;
UNP_LOCK_ASSERT();
unp = sotounpcb(so);
len = nam->sa_len - offsetof(struct sockaddr_un, sun_path);
if (len <= 0)
return (EINVAL);
strlcpy(buf, soun->sun_path, len + 1);
UNP_UNLOCK();
sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
mtx_lock(&Giant);
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf, td);
error = namei(&nd);
if (error)
vp = NULL;
else
vp = nd.ni_vp;
ASSERT_VOP_LOCKED(vp, "unp_connect");
NDFREE(&nd, NDF_ONLY_PNBUF);
if (error)
goto bad;
if (vp->v_type != VSOCK) {
error = ENOTSOCK;
goto bad;
}
error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td);
if (error)
goto bad;
mtx_unlock(&Giant);
UNP_LOCK();
unp = sotounpcb(so);
if (unp == NULL) {
error = EINVAL;
goto bad2;
}
so2 = vp->v_socket;
if (so2 == NULL) {
error = ECONNREFUSED;
goto bad2;
}
if (so->so_type != so2->so_type) {
error = EPROTOTYPE;
goto bad2;
}
if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
if (so2->so_options & SO_ACCEPTCONN) {
/*
* NB: drop locks here so unp_attach is entered
* w/o locks; this avoids a recursive lock
* of the head and holding sleep locks across
* a (potentially) blocking malloc.
*/
UNP_UNLOCK();
so3 = sonewconn(so2, 0);
UNP_LOCK();
} else
so3 = NULL;
if (so3 == NULL) {
error = ECONNREFUSED;
goto bad2;
}
unp = sotounpcb(so);
unp2 = sotounpcb(so2);
unp3 = sotounpcb(so3);
if (unp2->unp_addr != NULL) {
bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len);
unp3->unp_addr = (struct sockaddr_un *) sa;
sa = NULL;
}
/*
* unp_peercred management:
*
* The connecter's (client's) credentials are copied
* from its process structure at the time of connect()
* (which is now).
*/
cru2x(td->td_ucred, &unp3->unp_peercred);
unp3->unp_flags |= UNP_HAVEPC;
/*
* The receiver's (server's) credentials are copied
* from the unp_peercred member of socket on which the
* former called listen(); unp_listen() cached that
* process's credentials at that time so we can use
* them now.
*/
KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED,
("unp_connect: listener without cached peercred"));
memcpy(&unp->unp_peercred, &unp2->unp_peercred,
sizeof(unp->unp_peercred));
unp->unp_flags |= UNP_HAVEPC;
#ifdef MAC
SOCK_LOCK(so);
mac_set_socket_peer_from_socket(so, so3);
mac_set_socket_peer_from_socket(so3, so);
SOCK_UNLOCK(so);
#endif
so2 = so3;
}
error = unp_connect2(so, so2, PRU_CONNECT);
bad2:
UNP_UNLOCK();
mtx_lock(&Giant);
bad:
mtx_assert(&Giant, MA_OWNED);
if (vp != NULL)
vput(vp);
mtx_unlock(&Giant);
free(sa, M_SONAME);
UNP_LOCK();
return (error);
}
static int
unp_connect2(struct socket *so, struct socket *so2, int req)
{
struct unpcb *unp = sotounpcb(so);
struct unpcb *unp2;
UNP_LOCK_ASSERT();
if (so2->so_type != so->so_type)
return (EPROTOTYPE);
unp2 = sotounpcb(so2);
unp->unp_conn = unp2;
switch (so->so_type) {
case SOCK_DGRAM:
LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink);
soisconnected(so);
break;
case SOCK_STREAM:
unp2->unp_conn = unp;
if (req == PRU_CONNECT &&
((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT))
soisconnecting(so);
else
soisconnected(so);
soisconnected(so2);
break;
default:
panic("unp_connect2");
}
return (0);
}
static void
unp_disconnect(struct unpcb *unp)
{
struct unpcb *unp2 = unp->unp_conn;
struct socket *so;
UNP_LOCK_ASSERT();
if (unp2 == NULL)
return;
unp->unp_conn = NULL;
switch (unp->unp_socket->so_type) {
case SOCK_DGRAM:
LIST_REMOVE(unp, unp_reflink);
so = unp->unp_socket;
SOCK_LOCK(so);
so->so_state &= ~SS_ISCONNECTED;
SOCK_UNLOCK(so);
break;
case SOCK_STREAM:
soisdisconnected(unp->unp_socket);
unp2->unp_conn = NULL;
soisdisconnected(unp2->unp_socket);
break;
}
}
#ifdef notdef
void
unp_abort(struct unpcb *unp)
{
unp_detach(unp);
UNP_UNLOCK_ASSERT();
}
#endif
/*
* unp_pcblist() assumes that UNIX domain socket memory is never reclaimed
* by the zone (UMA_ZONE_NOFREE), and as such potentially stale pointers
* are safe to reference. It first scans the list of struct unpcb's to
* generate a pointer list, then it rescans its list one entry at a time to
* externalize and copyout. It checks the generation number to see if a
* struct unpcb has been reused, and will skip it if so.
*/
static int
unp_pcblist(SYSCTL_HANDLER_ARGS)
{
int error, i, n;
struct unpcb *unp, **unp_list;
unp_gen_t gencnt;
struct xunpgen *xug;
struct unp_head *head;
struct xunpcb *xu;
head = ((intptr_t)arg1 == SOCK_DGRAM ? &unp_dhead : &unp_shead);
/*
* The process of preparing the PCB list is too time-consuming and
* resource-intensive to repeat twice on every request.
*/
if (req->oldptr == NULL) {
n = unp_count;
req->oldidx = 2 * (sizeof *xug)
+ (n + n/8) * sizeof(struct xunpcb);
return (0);
}
if (req->newptr != NULL)
return (EPERM);
/*
* OK, now we're committed to doing something.
*/
xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK);
UNP_LOCK();
gencnt = unp_gencnt;
n = unp_count;
UNP_UNLOCK();
xug->xug_len = sizeof *xug;
xug->xug_count = n;
xug->xug_gen = gencnt;
xug->xug_sogen = so_gencnt;
error = SYSCTL_OUT(req, xug, sizeof *xug);
if (error) {
free(xug, M_TEMP);
return (error);
}
unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK);
UNP_LOCK();
for (unp = LIST_FIRST(head), i = 0; unp && i < n;
unp = LIST_NEXT(unp, unp_link)) {
if (unp->unp_gencnt <= gencnt) {
if (cr_cansee(req->td->td_ucred,
unp->unp_socket->so_cred))
continue;
unp_list[i++] = unp;
}
}
UNP_UNLOCK();
n = i; /* in case we lost some during malloc */
error = 0;
xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK | M_ZERO);
for (i = 0; i < n; i++) {
unp = unp_list[i];
if (unp->unp_gencnt <= gencnt) {
xu->xu_len = sizeof *xu;
xu->xu_unpp = unp;
/*
* XXX - need more locking here to protect against
* connect/disconnect races for SMP.
*/
if (unp->unp_addr != NULL)
bcopy(unp->unp_addr, &xu->xu_addr,
unp->unp_addr->sun_len);
if (unp->unp_conn != NULL &&
unp->unp_conn->unp_addr != NULL)
bcopy(unp->unp_conn->unp_addr,
&xu->xu_caddr,
unp->unp_conn->unp_addr->sun_len);
bcopy(unp, &xu->xu_unp, sizeof *unp);
sotoxsocket(unp->unp_socket, &xu->xu_socket);
error = SYSCTL_OUT(req, xu, sizeof *xu);
}
}
free(xu, M_TEMP);
if (!error) {
/*
* Give the user an updated idea of our state.
* If the generation differs from what we told
* her before, she knows that something happened
* while we were processing this request, and it
* might be necessary to retry.
*/
xug->xug_gen = unp_gencnt;
xug->xug_sogen = so_gencnt;
xug->xug_count = unp_count;
error = SYSCTL_OUT(req, xug, sizeof *xug);
}
free(unp_list, M_TEMP);
free(xug, M_TEMP);
return (error);
}
SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD,
(caddr_t)(long)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb",
"List of active local datagram sockets");
SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD,
(caddr_t)(long)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb",
"List of active local stream sockets");
static void
unp_shutdown(struct unpcb *unp)
{
struct socket *so;
UNP_LOCK_ASSERT();
if (unp->unp_socket->so_type == SOCK_STREAM && unp->unp_conn &&
(so = unp->unp_conn->unp_socket))
socantrcvmore(so);
}
static void
unp_drop(struct unpcb *unp, int errno)
{
struct socket *so = unp->unp_socket;
UNP_LOCK_ASSERT();
so->so_error = errno;
unp_disconnect(unp);
}
#ifdef notdef
void
unp_drain(void)
{
}
#endif
static void
unp_freerights(struct file **rp, int fdcount)
{
int i;
struct file *fp;
for (i = 0; i < fdcount; i++) {
fp = *rp;
/*
* zero the pointer before calling
* unp_discard since it may end up
* in unp_gc()..
*
* XXXRW: This is less true than it used to be.
*/
*rp++ = 0;
unp_discard(fp);
}
}
int
unp_externalize(struct mbuf *control, struct mbuf **controlp)
{
struct thread *td = curthread; /* XXX */
struct cmsghdr *cm = mtod(control, struct cmsghdr *);
int i;
int *fdp;
struct file **rp;
struct file *fp;
void *data;
socklen_t clen = control->m_len, datalen;
int error, newfds;
int f;
u_int newlen;
UNP_UNLOCK_ASSERT();
error = 0;
if (controlp != NULL) /* controlp == NULL => free control messages */
*controlp = NULL;
while (cm != NULL) {
if (sizeof(*cm) > clen || cm->cmsg_len > clen) {
error = EINVAL;
break;
}
data = CMSG_DATA(cm);
datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;
if (cm->cmsg_level == SOL_SOCKET
&& cm->cmsg_type == SCM_RIGHTS) {
newfds = datalen / sizeof(struct file *);
rp = data;
/* If we're not outputting the descriptors free them. */
if (error || controlp == NULL) {
unp_freerights(rp, newfds);
goto next;
}
FILEDESC_LOCK(td->td_proc->p_fd);
/* if the new FD's will not fit free them. */
if (!fdavail(td, newfds)) {
FILEDESC_UNLOCK(td->td_proc->p_fd);
error = EMSGSIZE;
unp_freerights(rp, newfds);
goto next;
}
/*
* now change each pointer to an fd in the global
* table to an integer that is the index to the
* local fd table entry that we set up to point
* to the global one we are transferring.
*/
newlen = newfds * sizeof(int);
*controlp = sbcreatecontrol(NULL, newlen,
SCM_RIGHTS, SOL_SOCKET);
if (*controlp == NULL) {
FILEDESC_UNLOCK(td->td_proc->p_fd);
error = E2BIG;
unp_freerights(rp, newfds);
goto next;
}
fdp = (int *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
for (i = 0; i < newfds; i++) {
if (fdalloc(td, 0, &f))
panic("unp_externalize fdalloc failed");
fp = *rp++;
td->td_proc->p_fd->fd_ofiles[f] = fp;
FILE_LOCK(fp);
fp->f_msgcount--;
FILE_UNLOCK(fp);
unp_rights--;
*fdp++ = f;
}
FILEDESC_UNLOCK(td->td_proc->p_fd);
} else { /* We can just copy anything else across */
if (error || controlp == NULL)
goto next;
*controlp = sbcreatecontrol(NULL, datalen,
cm->cmsg_type, cm->cmsg_level);
if (*controlp == NULL) {
error = ENOBUFS;
goto next;
}
bcopy(data,
CMSG_DATA(mtod(*controlp, struct cmsghdr *)),
datalen);
}
controlp = &(*controlp)->m_next;
next:
if (CMSG_SPACE(datalen) < clen) {
clen -= CMSG_SPACE(datalen);
cm = (struct cmsghdr *)
((caddr_t)cm + CMSG_SPACE(datalen));
} else {
clen = 0;
cm = NULL;
}
}
m_freem(control);
return (error);
}
void
unp_init(void)
{
unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL,
NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
if (unp_zone == NULL)
panic("unp_init");
uma_zone_set_max(unp_zone, nmbclusters);
LIST_INIT(&unp_dhead);
LIST_INIT(&unp_shead);
TASK_INIT(&unp_gc_task, 0, unp_gc, NULL);
UNP_LOCK_INIT();
}
static int
unp_internalize(struct mbuf **controlp, struct thread *td)
{
struct mbuf *control = *controlp;
struct proc *p = td->td_proc;
struct filedesc *fdescp = p->p_fd;
struct cmsghdr *cm = mtod(control, struct cmsghdr *);
struct cmsgcred *cmcred;
struct file **rp;
struct file *fp;
struct timeval *tv;
int i, fd, *fdp;
void *data;
socklen_t clen = control->m_len, datalen;
int error, oldfds;
u_int newlen;
UNP_UNLOCK_ASSERT();
error = 0;
*controlp = NULL;
while (cm != NULL) {
if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET
|| cm->cmsg_len > clen) {
error = EINVAL;
goto out;
}
data = CMSG_DATA(cm);
datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;
switch (cm->cmsg_type) {
/*
* Fill in credential information.
*/
case SCM_CREDS:
*controlp = sbcreatecontrol(NULL, sizeof(*cmcred),
SCM_CREDS, SOL_SOCKET);
if (*controlp == NULL) {
error = ENOBUFS;
goto out;
}
cmcred = (struct cmsgcred *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
cmcred->cmcred_pid = p->p_pid;
cmcred->cmcred_uid = td->td_ucred->cr_ruid;
cmcred->cmcred_gid = td->td_ucred->cr_rgid;
cmcred->cmcred_euid = td->td_ucred->cr_uid;
cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups,
CMGROUP_MAX);
for (i = 0; i < cmcred->cmcred_ngroups; i++)
cmcred->cmcred_groups[i] =
td->td_ucred->cr_groups[i];
break;
case SCM_RIGHTS:
oldfds = datalen / sizeof (int);
/*
* check that all the FDs passed in refer to legal files
* If not, reject the entire operation.
*/
fdp = data;
FILEDESC_LOCK(fdescp);
for (i = 0; i < oldfds; i++) {
fd = *fdp++;
if ((unsigned)fd >= fdescp->fd_nfiles ||
fdescp->fd_ofiles[fd] == NULL) {
FILEDESC_UNLOCK(fdescp);
error = EBADF;
goto out;
}
fp = fdescp->fd_ofiles[fd];
if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) {
FILEDESC_UNLOCK(fdescp);
error = EOPNOTSUPP;
goto out;
}
}
/*
* Now replace the integer FDs with pointers to
* the associated global file table entry..
*/
newlen = oldfds * sizeof(struct file *);
*controlp = sbcreatecontrol(NULL, newlen,
SCM_RIGHTS, SOL_SOCKET);
if (*controlp == NULL) {
FILEDESC_UNLOCK(fdescp);
error = E2BIG;
goto out;
}
fdp = data;
rp = (struct file **)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
for (i = 0; i < oldfds; i++) {
fp = fdescp->fd_ofiles[*fdp++];
*rp++ = fp;
FILE_LOCK(fp);
fp->f_count++;
fp->f_msgcount++;
FILE_UNLOCK(fp);
unp_rights++;
}
FILEDESC_UNLOCK(fdescp);
break;
case SCM_TIMESTAMP:
*controlp = sbcreatecontrol(NULL, sizeof(*tv),
SCM_TIMESTAMP, SOL_SOCKET);
if (*controlp == NULL) {
error = ENOBUFS;
goto out;
}
tv = (struct timeval *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
microtime(tv);
break;
default:
error = EINVAL;
goto out;
}
controlp = &(*controlp)->m_next;
if (CMSG_SPACE(datalen) < clen) {
clen -= CMSG_SPACE(datalen);
cm = (struct cmsghdr *)
((caddr_t)cm + CMSG_SPACE(datalen));
} else {
clen = 0;
cm = NULL;
}
}
out:
m_freem(control);
return (error);
}
struct mbuf *
unp_addsockcred(struct thread *td, struct mbuf *control)
{
struct mbuf *m, *n;
struct sockcred *sc;
int ngroups;
int i;
ngroups = MIN(td->td_ucred->cr_ngroups, CMGROUP_MAX);
m = sbcreatecontrol(NULL, SOCKCREDSIZE(ngroups), SCM_CREDS, SOL_SOCKET);
if (m == NULL)
return (control);
m->m_next = NULL;
sc = (struct sockcred *) CMSG_DATA(mtod(m, struct cmsghdr *));
sc->sc_uid = td->td_ucred->cr_ruid;
sc->sc_euid = td->td_ucred->cr_uid;
sc->sc_gid = td->td_ucred->cr_rgid;
sc->sc_egid = td->td_ucred->cr_gid;
sc->sc_ngroups = ngroups;
for (i = 0; i < sc->sc_ngroups; i++)
sc->sc_groups[i] = td->td_ucred->cr_groups[i];
/*
* If a control message already exists, append us to the end.
*/
if (control != NULL) {
for (n = control; n->m_next != NULL; n = n->m_next)
;
n->m_next = m;
} else
control = m;
return (control);
}
/*
* unp_defer indicates whether additional work has been defered for a future
* pass through unp_gc(). It is thread local and does not require explicit
* synchronization.
*/
static int unp_defer;
static int unp_taskcount;
SYSCTL_INT(_net_local, OID_AUTO, taskcount, CTLFLAG_RD, &unp_taskcount, 0, "");
static int unp_recycled;
SYSCTL_INT(_net_local, OID_AUTO, recycled, CTLFLAG_RD, &unp_recycled, 0, "");
static void
unp_gc(__unused void *arg, int pending)
{
struct file *fp, *nextfp;
struct socket *so;
struct file **extra_ref, **fpp;
int nunref, i;
int nfiles_snap;
int nfiles_slack = 20;
unp_taskcount++;
unp_defer = 0;
/*
* before going through all this, set all FDs to
* be NOT defered and NOT externally accessible
*/
sx_slock(&filelist_lock);
LIST_FOREACH(fp, &filehead, f_list)
fp->f_gcflag &= ~(FMARK|FDEFER);
do {
KASSERT(unp_defer >= 0, ("unp_gc: unp_defer %d", unp_defer));
LIST_FOREACH(fp, &filehead, f_list) {
FILE_LOCK(fp);
/*
* If the file is not open, skip it -- could be a
* file in the process of being opened, or in the
* process of being closed. If the file is
* "closing", it may have been marked for deferred
* consideration. Clear the flag now if so.
*/
if (fp->f_count == 0) {
if (fp->f_gcflag & FDEFER)
unp_defer--;
fp->f_gcflag &= ~(FMARK|FDEFER);
FILE_UNLOCK(fp);
continue;
}
/*
* If we already marked it as 'defer' in a
* previous pass, then try process it this time
* and un-mark it
*/
if (fp->f_gcflag & FDEFER) {
fp->f_gcflag &= ~FDEFER;
unp_defer--;
} else {
/*
* if it's not defered, then check if it's
* already marked.. if so skip it
*/
if (fp->f_gcflag & FMARK) {
FILE_UNLOCK(fp);
continue;
}
/*
* If all references are from messages
* in transit, then skip it. it's not
* externally accessible.
*/
if (fp->f_count == fp->f_msgcount) {
FILE_UNLOCK(fp);
continue;
}
/*
* If it got this far then it must be
* externally accessible.
*/
fp->f_gcflag |= FMARK;
}
/*
* either it was defered, or it is externally
* accessible and not already marked so.
* Now check if it is possibly one of OUR sockets.
*/
if (fp->f_type != DTYPE_SOCKET ||
(so = fp->f_data) == NULL) {
FILE_UNLOCK(fp);
continue;
}
FILE_UNLOCK(fp);
if (so->so_proto->pr_domain != &localdomain ||
(so->so_proto->pr_flags&PR_RIGHTS) == 0)
continue;
/*
* So, Ok, it's one of our sockets and it IS externally
* accessible (or was defered). Now we look
* to see if we hold any file descriptors in its
* message buffers. Follow those links and mark them
* as accessible too.
*/
SOCKBUF_LOCK(&so->so_rcv);
unp_scan(so->so_rcv.sb_mb, unp_mark);
SOCKBUF_UNLOCK(&so->so_rcv);
}
} while (unp_defer);
sx_sunlock(&filelist_lock);
/*
* XXXRW: The following comments need updating for a post-SMPng and
* deferred unp_gc() world, but are still generally accurate.
*
* We grab an extra reference to each of the file table entries
* that are not otherwise accessible and then free the rights
* that are stored in messages on them.
*
* The bug in the orginal code is a little tricky, so I'll describe
* what's wrong with it here.
*
* It is incorrect to simply unp_discard each entry for f_msgcount
* times -- consider the case of sockets A and B that contain
* references to each other. On a last close of some other socket,
* we trigger a gc since the number of outstanding rights (unp_rights)
* is non-zero. If during the sweep phase the gc code unp_discards,
* we end up doing a (full) closef on the descriptor. A closef on A
* results in the following chain. Closef calls soo_close, which
* calls soclose. Soclose calls first (through the switch
* uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply
* returns because the previous instance had set unp_gcing, and
* we return all the way back to soclose, which marks the socket
* with SS_NOFDREF, and then calls sofree. Sofree calls sorflush
* to free up the rights that are queued in messages on the socket A,
* i.e., the reference on B. The sorflush calls via the dom_dispose
* switch unp_dispose, which unp_scans with unp_discard. This second
* instance of unp_discard just calls closef on B.
*
* Well, a similar chain occurs on B, resulting in a sorflush on B,
* which results in another closef on A. Unfortunately, A is already
* being closed, and the descriptor has already been marked with
* SS_NOFDREF, and soclose panics at this point.
*
* Here, we first take an extra reference to each inaccessible
* descriptor. Then, we call sorflush ourself, since we know
* it is a Unix domain socket anyhow. After we destroy all the
* rights carried in messages, we do a last closef to get rid
* of our extra reference. This is the last close, and the
* unp_detach etc will shut down the socket.
*
* 91/09/19, bsy@cs.cmu.edu
*/
again:
nfiles_snap = openfiles + nfiles_slack; /* some slack */
extra_ref = malloc(nfiles_snap * sizeof(struct file *), M_TEMP,
M_WAITOK);
sx_slock(&filelist_lock);
if (nfiles_snap < openfiles) {
sx_sunlock(&filelist_lock);
free(extra_ref, M_TEMP);
nfiles_slack += 20;
goto again;
}
for (nunref = 0, fp = LIST_FIRST(&filehead), fpp = extra_ref;
fp != NULL; fp = nextfp) {
nextfp = LIST_NEXT(fp, f_list);
FILE_LOCK(fp);
/*
* If it's not open, skip it
*/
if (fp->f_count == 0) {
FILE_UNLOCK(fp);
continue;
}
/*
* If all refs are from msgs, and it's not marked accessible
* then it must be referenced from some unreachable cycle
* of (shut-down) FDs, so include it in our
* list of FDs to remove
*/
if (fp->f_count == fp->f_msgcount && !(fp->f_gcflag & FMARK)) {
*fpp++ = fp;
nunref++;
fp->f_count++;
}
FILE_UNLOCK(fp);
}
sx_sunlock(&filelist_lock);
/*
* for each FD on our hit list, do the following two things
*/
for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) {
struct file *tfp = *fpp;
FILE_LOCK(tfp);
if (tfp->f_type == DTYPE_SOCKET &&
tfp->f_data != NULL) {
FILE_UNLOCK(tfp);
sorflush(tfp->f_data);
} else {
FILE_UNLOCK(tfp);
}
}
for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) {
closef(*fpp, (struct thread *) NULL);
unp_recycled++;
}
free(extra_ref, M_TEMP);
}
void
unp_dispose(struct mbuf *m)
{
if (m)
unp_scan(m, unp_discard);
}
static int
unp_listen(struct socket *so, struct unpcb *unp, int backlog,
struct thread *td)
{
int error;
UNP_LOCK_ASSERT();
SOCK_LOCK(so);
error = solisten_proto_check(so);
if (error == 0) {
cru2x(td->td_ucred, &unp->unp_peercred);
unp->unp_flags |= UNP_HAVEPCCACHED;
solisten_proto(so, backlog);
}
SOCK_UNLOCK(so);
return (error);
}
static void
unp_scan(struct mbuf *m0, void (*op)(struct file *))
{
struct mbuf *m;
struct file **rp;
struct cmsghdr *cm;
void *data;
int i;
socklen_t clen, datalen;
int qfds;
while (m0 != NULL) {
for (m = m0; m; m = m->m_next) {
if (m->m_type != MT_CONTROL)
continue;
cm = mtod(m, struct cmsghdr *);
clen = m->m_len;
while (cm != NULL) {
if (sizeof(*cm) > clen || cm->cmsg_len > clen)
break;
data = CMSG_DATA(cm);
datalen = (caddr_t)cm + cm->cmsg_len
- (caddr_t)data;
if (cm->cmsg_level == SOL_SOCKET &&
cm->cmsg_type == SCM_RIGHTS) {
qfds = datalen / sizeof (struct file *);
rp = data;
for (i = 0; i < qfds; i++)
(*op)(*rp++);
}
if (CMSG_SPACE(datalen) < clen) {
clen -= CMSG_SPACE(datalen);
cm = (struct cmsghdr *)
((caddr_t)cm + CMSG_SPACE(datalen));
} else {
clen = 0;
cm = NULL;
}
}
}
m0 = m0->m_act;
}
}
static void
unp_mark(struct file *fp)
{
if (fp->f_gcflag & FMARK)
return;
unp_defer++;
fp->f_gcflag |= (FMARK|FDEFER);
}
static void
unp_discard(struct file *fp)
{
UNP_LOCK();
FILE_LOCK(fp);
fp->f_msgcount--;
unp_rights--;
FILE_UNLOCK(fp);
UNP_UNLOCK();
(void) closef(fp, (struct thread *)NULL);
}
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