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004e08be60
freebsd-dev/sys/kern/uipc_usrreq.c
Pawel Jakub Dawidek 57fd3d5572 When we do open, we should lock the vnode exclusively. This fixes few races: 
- fifo race, where two threads assign v_fifoinfo,
- v_writecount modifications,
- v_object modifications,
- and probably more...

Discussed with:	kib, ups
Approved by:	re (rwatson)
2007-07-26 16:58:09 +00:00

2286 lines
57 KiB
C
Raw Blame History

/*-
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California.
* Copyright (c) 2004-2007 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
*/
/*
* UNIX Domain (Local) Sockets
*
* This is an implementation of UNIX (local) domain sockets. Each socket has
* an associated struct unpcb (UNIX protocol control block). Stream sockets
* may be connected to 0 or 1 other socket. Datagram sockets may be
* connected to 0, 1, or many other sockets. Sockets may be created and
* connected in pairs (socketpair(2)), or bound/connected to using the file
* system name space. For most purposes, only the receive socket buffer is
* used, as sending on one socket delivers directly to the receive socket
* buffer of a second socket.
*
* The implementation is substantially complicated by the fact that
* "ancillary data", such as file descriptors or credentials, may be passed
* across UNIX domain sockets. The potential for passing UNIX domain sockets
* over other UNIX domain sockets requires the implementation of a simple
* garbage collector to find and tear down cycles of disconnected sockets.
*
* TODO:
* SEQPACKET, RDM
* rethink name space problems
* need a proper out-of-band
* lock pushdown
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#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/eventhandler.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mbuf.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/resourcevar.h>
#include <sys/rwlock.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>
#ifdef DDB
#include <ddb/ddb.h>
#endif
#include <security/mac/mac_framework.h>
#include <vm/uma.h>
static uma_zone_t unp_zone;
static unp_gen_t unp_gencnt;
static u_int unp_count; /* Count of local sockets. */
static ino_t unp_ino; /* Prototype for fake inode numbers. */
static int unp_rights; /* File descriptors in flight. */
static struct unp_head unp_shead; /* List of local stream sockets. */
static struct unp_head unp_dhead; /* List of local datagram sockets. */
static const struct sockaddr sun_noname = { sizeof(sun_noname), AF_LOCAL };
/*
* 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;
/*
* 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;
SYSCTL_NODE(_net, PF_LOCAL, local, CTLFLAG_RW, 0, "Local domain");
SYSCTL_NODE(_net_local, SOCK_STREAM, stream, CTLFLAG_RW, 0, "SOCK_STREAM");
SYSCTL_NODE(_net_local, SOCK_DGRAM, dgram, CTLFLAG_RW, 0, "SOCK_DGRAM");
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_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_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, "");
/*-
* Locking and synchronization:
*
* The global UNIX domain socket rwlock (unp_global_rwlock) protects all
* global variables, including the linked lists tracking the set of allocated
* UNIX domain sockets. The global rwlock also serves to prevent deadlock
* when more than one PCB lock is acquired at a time (i.e., during
* connect()). Finally, the global rwlock protects uncounted references from
* vnodes to sockets bound to those vnodes: to safely dereference the
* v_socket pointer, the global rwlock must be held while a full reference is
* acquired.
*
* UNIX domain sockets each have an unpcb hung off of their so_pcb pointer,
* allocated in pru_attach() and freed in pru_detach(). The validity of that
* pointer is an invariant, so no lock is required to dereference the so_pcb
* pointer if a valid socket reference is held by the caller. In practice,
* this is always true during operations performed on a socket. Each unpcb
* has a back-pointer to its socket, unp_socket, which will be stable under
* the same circumstances.
*
* This pointer may only be safely dereferenced as long as a valid reference
* to the unpcb is held. Typically, this reference will be from the socket,
* or from another unpcb when the referring unpcb's lock is held (in order
* that the reference not be invalidated during use). For example, to follow
* unp->unp_conn->unp_socket, you need unlock the lock on unp, not unp_conn,
* as unp_socket remains valid as long as the reference to unp_conn is valid.
*
* Fields of unpcbss are locked using a per-unpcb lock, unp_mtx. Individual
* atomic reads without the lock may be performed "lockless", but more
* complex reads and read-modify-writes require the mutex to be held. No
* lock order is defined between unpcb locks -- multiple unpcb locks may be
* acquired at the same time only when holding the global UNIX domain socket
* rwlock exclusively, which prevents deadlocks.
*
* Blocking with UNIX domain sockets is a tricky issue: unlike most network
* protocols, bind() is a non-atomic operation, and connect() requires
* potential sleeping in the protocol, due to potentially waiting on local or
* distributed file systems. We try to separate "lookup" operations, which
* may sleep, and the IPC operations themselves, which typically can occur
* with relative atomicity as locks can be held over the entire operation.
*
* Another tricky issue is simultaneous multi-threaded or multi-process
* access to a single UNIX domain socket. These are handled by the flags
* UNP_CONNECTING and UNP_BINDING, which prevent concurrent connecting or
* binding, both of which involve dropping UNIX domain socket locks in order
* to perform namei() and other file system operations.
*/
static struct rwlock unp_global_rwlock;
#define UNP_GLOBAL_LOCK_INIT() rw_init(&unp_global_rwlock, \
"unp_global_rwlock")
#define UNP_GLOBAL_LOCK_ASSERT() rw_assert(&unp_global_rwlock, \
RA_LOCKED)
#define UNP_GLOBAL_UNLOCK_ASSERT() rw_assert(&unp_global_rwlock, \
RA_UNLOCKED)
#define UNP_GLOBAL_WLOCK() rw_wlock(&unp_global_rwlock)
#define UNP_GLOBAL_WUNLOCK() rw_wunlock(&unp_global_rwlock)
#define UNP_GLOBAL_WLOCK_ASSERT() rw_assert(&unp_global_rwlock, \
RA_WLOCKED)
#define UNP_GLOBAL_WOWNED() rw_wowned(&unp_global_rwlock)
#define UNP_GLOBAL_RLOCK() rw_rlock(&unp_global_rwlock)
#define UNP_GLOBAL_RUNLOCK() rw_runlock(&unp_global_rwlock)
#define UNP_GLOBAL_RLOCK_ASSERT() rw_assert(&unp_global_rwlock, \
RA_RLOCKED)
#define UNP_PCB_LOCK_INIT(unp) mtx_init(&(unp)->unp_mtx, \
"unp_mtx", "unp_mtx", \
MTX_DUPOK|MTX_DEF|MTX_RECURSE)
#define UNP_PCB_LOCK_DESTROY(unp) mtx_destroy(&(unp)->unp_mtx)
#define UNP_PCB_LOCK(unp) mtx_lock(&(unp)->unp_mtx)
#define UNP_PCB_UNLOCK(unp) mtx_unlock(&(unp)->unp_mtx)
#define UNP_PCB_LOCK_ASSERT(unp) mtx_assert(&(unp)->unp_mtx, MA_OWNED)
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 *unp, struct unpcb *unp2);
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 struct mbuf *unp_addsockcred(struct thread *, struct mbuf *);
/*
* Definitions of protocols supported in the LOCAL domain.
*/
static struct domain localdomain;
static struct protosw localsw[] = {
{
.pr_type = SOCK_STREAM,
.pr_domain = &localdomain,
.pr_flags = PR_CONNREQUIRED|PR_WANTRCVD|PR_RIGHTS,
.pr_ctloutput = &uipc_ctloutput,
.pr_usrreqs = &uipc_usrreqs
},
{
.pr_type = SOCK_DGRAM,
.pr_domain = &localdomain,
.pr_flags = PR_ATOMIC|PR_ADDR|PR_RIGHTS,
.pr_usrreqs = &uipc_usrreqs
},
};
static struct domain localdomain = {
.dom_family = AF_LOCAL,
.dom_name = "local",
.dom_init = unp_init,
.dom_externalize = unp_externalize,
.dom_dispose = unp_dispose,
.dom_protosw = localsw,
.dom_protoswNPROTOSW = &localsw[sizeof(localsw)/sizeof(localsw[0])]
};
DOMAIN_SET(local);
static void
uipc_abort(struct socket *so)
{
struct unpcb *unp, *unp2;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_abort: unp == NULL"));
UNP_GLOBAL_WLOCK();
UNP_PCB_LOCK(unp);
unp2 = unp->unp_conn;
if (unp2 != NULL) {
UNP_PCB_LOCK(unp2);
unp_drop(unp2, ECONNABORTED);
UNP_PCB_UNLOCK(unp2);
}
UNP_PCB_UNLOCK(unp);
UNP_GLOBAL_WUNLOCK();
}
static int
uipc_accept(struct socket *so, struct sockaddr **nam)
{
struct unpcb *unp, *unp2;
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!).
*/
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_accept: unp == NULL"));
*nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
UNP_GLOBAL_RLOCK();
unp2 = unp->unp_conn;
if (unp2 != NULL && unp2->unp_addr != NULL) {
UNP_PCB_LOCK(unp2);
sa = (struct sockaddr *) unp2->unp_addr;
bcopy(sa, *nam, sa->sa_len);
UNP_PCB_UNLOCK(unp2);
} else {
sa = &sun_noname;
bcopy(sa, *nam, sa->sa_len);
}
UNP_GLOBAL_RUNLOCK();
return (0);
}
static int
uipc_attach(struct socket *so, int proto, struct thread *td)
{
u_long sendspace, recvspace;
struct unpcb *unp;
int error, locked;
KASSERT(so->so_pcb == NULL, ("uipc_attach: so_pcb != NULL"));
if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
switch (so->so_type) {
case SOCK_STREAM:
sendspace = unpst_sendspace;
recvspace = unpst_recvspace;
break;
case SOCK_DGRAM:
sendspace = unpdg_sendspace;
recvspace = unpdg_recvspace;
break;
default:
panic("uipc_attach");
}
error = soreserve(so, sendspace, recvspace);
if (error)
return (error);
}
unp = uma_zalloc(unp_zone, M_NOWAIT | M_ZERO);
if (unp == NULL)
return (ENOBUFS);
LIST_INIT(&unp->unp_refs);
UNP_PCB_LOCK_INIT(unp);
unp->unp_socket = so;
so->so_pcb = unp;
unp->unp_refcount = 1;
/*
* uipc_attach() may be called indirectly from within the UNIX domain
* socket code via sonewconn() in unp_connect(). Since rwlocks can
* not be recursed, we do the closest thing.
*/
locked = 0;
if (!UNP_GLOBAL_WOWNED()) {
UNP_GLOBAL_WLOCK();
locked = 1;
}
unp->unp_gencnt = ++unp_gencnt;
unp_count++;
LIST_INSERT_HEAD(so->so_type == SOCK_DGRAM ? &unp_dhead : &unp_shead,
unp, unp_link);
if (locked)
UNP_GLOBAL_WUNLOCK();
return (0);
}
static int
uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
{
struct sockaddr_un *soun = (struct sockaddr_un *)nam;
struct vattr vattr;
int error, namelen, vfslocked;
struct nameidata nd;
struct unpcb *unp;
struct vnode *vp;
struct mount *mp;
char *buf;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_bind: unp == NULL"));
namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path);
if (namelen <= 0)
return (EINVAL);
/*
* We don't allow simultaneous bind() calls on a single UNIX domain
* socket, so flag in-progress operations, and return an error if an
* operation is already in progress.
*
* Historically, we have not allowed a socket to be rebound, so this
* also returns an error. Not allowing re-binding simplifies the
* implementation and avoids a great many possible failure modes.
*/
UNP_PCB_LOCK(unp);
if (unp->unp_vnode != NULL) {
UNP_PCB_UNLOCK(unp);
return (EINVAL);
}
if (unp->unp_flags & UNP_BINDING) {
UNP_PCB_UNLOCK(unp);
return (EALREADY);
}
unp->unp_flags |= UNP_BINDING;
UNP_PCB_UNLOCK(unp);
buf = malloc(namelen + 1, M_TEMP, M_WAITOK);
strlcpy(buf, soun->sun_path, namelen + 1);
restart:
vfslocked = 0;
NDINIT(&nd, CREATE, MPSAFE | NOFOLLOW | LOCKPARENT | SAVENAME,
UIO_SYSSPACE, buf, td);
/* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */
error = namei(&nd);
if (error)
goto error;
vp = nd.ni_vp;
vfslocked = NDHASGIANT(&nd);
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 error;
}
error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH);
if (error)
goto error;
VFS_UNLOCK_GIANT(vfslocked);
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 error;
}
vp = nd.ni_vp;
ASSERT_VOP_ELOCKED(vp, "uipc_bind");
soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK);
UNP_GLOBAL_WLOCK();
UNP_PCB_LOCK(unp);
vp->v_socket = unp->unp_socket;
unp->unp_vnode = vp;
unp->unp_addr = soun;
unp->unp_flags &= ~UNP_BINDING;
UNP_PCB_UNLOCK(unp);
UNP_GLOBAL_WUNLOCK();
VOP_UNLOCK(vp, 0, td);
vn_finished_write(mp);
VFS_UNLOCK_GIANT(vfslocked);
free(buf, M_TEMP);
return (0);
error:
VFS_UNLOCK_GIANT(vfslocked);
UNP_PCB_LOCK(unp);
unp->unp_flags &= ~UNP_BINDING;
UNP_PCB_UNLOCK(unp);
free(buf, M_TEMP);
return (error);
}
static int
uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
{
int error;
KASSERT(td == curthread, ("uipc_connect: td != curthread"));
UNP_GLOBAL_WLOCK();
error = unp_connect(so, nam, td);
UNP_GLOBAL_WUNLOCK();
return (error);
}
static void
uipc_close(struct socket *so)
{
struct unpcb *unp, *unp2;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_close: unp == NULL"));
UNP_GLOBAL_WLOCK();
UNP_PCB_LOCK(unp);
unp2 = unp->unp_conn;
if (unp2 != NULL) {
UNP_PCB_LOCK(unp2);
unp_disconnect(unp, unp2);
UNP_PCB_UNLOCK(unp2);
}
UNP_PCB_UNLOCK(unp);
UNP_GLOBAL_WUNLOCK();
}
int
uipc_connect2(struct socket *so1, struct socket *so2)
{
struct unpcb *unp, *unp2;
int error;
UNP_GLOBAL_WLOCK();
unp = so1->so_pcb;
KASSERT(unp != NULL, ("uipc_connect2: unp == NULL"));
UNP_PCB_LOCK(unp);
unp2 = so2->so_pcb;
KASSERT(unp2 != NULL, ("uipc_connect2: unp2 == NULL"));
UNP_PCB_LOCK(unp2);
error = unp_connect2(so1, so2, PRU_CONNECT2);
UNP_PCB_UNLOCK(unp2);
UNP_PCB_UNLOCK(unp);
UNP_GLOBAL_WUNLOCK();
return (error);
}
/* control is EOPNOTSUPP */
static void
uipc_detach(struct socket *so)
{
struct unpcb *unp, *unp2;
struct sockaddr_un *saved_unp_addr;
struct vnode *vp;
int freeunp, local_unp_rights;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_detach: unp == NULL"));
UNP_GLOBAL_WLOCK();
UNP_PCB_LOCK(unp);
LIST_REMOVE(unp, unp_link);
unp->unp_gencnt = ++unp_gencnt;
--unp_count;
/*
* XXXRW: Should assert vp->v_socket == so.
*/
if ((vp = unp->unp_vnode) != NULL) {
unp->unp_vnode->v_socket = NULL;
unp->unp_vnode = NULL;
}
unp2 = unp->unp_conn;
if (unp2 != NULL) {
UNP_PCB_LOCK(unp2);
unp_disconnect(unp, unp2);
UNP_PCB_UNLOCK(unp2);
}
/*
* We hold the global lock, so it's OK to acquire multiple pcb locks
* at a time.
*/
while (!LIST_EMPTY(&unp->unp_refs)) {
struct unpcb *ref = LIST_FIRST(&unp->unp_refs);
UNP_PCB_LOCK(ref);
unp_drop(ref, ECONNRESET);
UNP_PCB_UNLOCK(ref);
}
UNP_GLOBAL_WUNLOCK();
unp->unp_socket->so_pcb = NULL;
local_unp_rights = unp_rights;
saved_unp_addr = unp->unp_addr;
unp->unp_addr = NULL;
unp->unp_refcount--;
freeunp = (unp->unp_refcount == 0);
if (saved_unp_addr != NULL)
FREE(saved_unp_addr, M_SONAME);
if (freeunp) {
UNP_PCB_LOCK_DESTROY(unp);
uma_zfree(unp_zone, unp);
} else
UNP_PCB_UNLOCK(unp);
if (vp) {
int vfslocked;
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
vrele(vp);
VFS_UNLOCK_GIANT(vfslocked);
}
if (local_unp_rights)
taskqueue_enqueue(taskqueue_thread, &unp_gc_task);
}
static int
uipc_disconnect(struct socket *so)
{
struct unpcb *unp, *unp2;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_disconnect: unp == NULL"));
UNP_GLOBAL_WLOCK();
UNP_PCB_LOCK(unp);
unp2 = unp->unp_conn;
if (unp2 != NULL) {
UNP_PCB_LOCK(unp2);
unp_disconnect(unp, unp2);
UNP_PCB_UNLOCK(unp2);
}
UNP_PCB_UNLOCK(unp);
UNP_GLOBAL_WUNLOCK();
return (0);
}
static int
uipc_listen(struct socket *so, int backlog, struct thread *td)
{
struct unpcb *unp;
int error;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_listen: unp == NULL"));
UNP_PCB_LOCK(unp);
if (unp->unp_vnode == NULL) {
UNP_PCB_UNLOCK(unp);
return (EINVAL);
}
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);
UNP_PCB_UNLOCK(unp);
return (error);
}
static int
uipc_peeraddr(struct socket *so, struct sockaddr **nam)
{
struct unpcb *unp, *unp2;
const struct sockaddr *sa;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_peeraddr: unp == NULL"));
*nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
UNP_PCB_LOCK(unp);
/*
* 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.
*/
unp2 = unp->unp_conn;
if (unp2 != NULL) {
UNP_PCB_LOCK(unp2);
if (unp2->unp_addr != NULL)
sa = (struct sockaddr *) unp->unp_conn->unp_addr;
else
sa = &sun_noname;
bcopy(sa, *nam, sa->sa_len);
UNP_PCB_UNLOCK(unp2);
} else {
sa = &sun_noname;
bcopy(sa, *nam, sa->sa_len);
}
UNP_PCB_UNLOCK(unp);
return (0);
}
static int
uipc_rcvd(struct socket *so, int flags)
{
struct unpcb *unp, *unp2;
struct socket *so2;
u_int mbcnt, sbcc;
u_long newhiwat;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_rcvd: unp == NULL"));
if (so->so_type == SOCK_DGRAM)
panic("uipc_rcvd DGRAM?");
if (so->so_type != SOCK_STREAM)
panic("uipc_rcvd unknown socktype");
/*
* Adjust backpressure on sender and wakeup any waiting to write.
*
* The unp lock is acquired to maintain the validity of the unp_conn
* pointer; no lock on unp2 is required as unp2->unp_socket will be
* static as long as we don't permit unp2 to disconnect from unp,
* which is prevented by the lock on unp. We cache values from
* so_rcv to avoid holding the so_rcv lock over the entire
* transaction on the remote so_snd.
*/
SOCKBUF_LOCK(&so->so_rcv);
mbcnt = so->so_rcv.sb_mbcnt;
sbcc = so->so_rcv.sb_cc;
SOCKBUF_UNLOCK(&so->so_rcv);
UNP_PCB_LOCK(unp);
unp2 = unp->unp_conn;
if (unp2 == NULL) {
UNP_PCB_UNLOCK(unp);
return (0);
}
so2 = unp2->unp_socket;
SOCKBUF_LOCK(&so2->so_snd);
so2->so_snd.sb_mbmax += unp->unp_mbcnt - mbcnt;
newhiwat = so2->so_snd.sb_hiwat + unp->unp_cc - sbcc;
(void)chgsbsize(so2->so_cred->cr_uidinfo, &so2->so_snd.sb_hiwat,
newhiwat, RLIM_INFINITY);
sowwakeup_locked(so2);
unp->unp_mbcnt = mbcnt;
unp->unp_cc = sbcc;
UNP_PCB_UNLOCK(unp);
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)
{
struct unpcb *unp, *unp2;
struct socket *so2;
u_int mbcnt, sbcc;
u_long newhiwat;
int error = 0;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_send: unp == NULL"));
if (flags & PRUS_OOB) {
error = EOPNOTSUPP;
goto release;
}
if (control != NULL && (error = unp_internalize(&control, td)))
goto release;
if ((nam != NULL) || (flags & PRUS_EOF))
UNP_GLOBAL_WLOCK();
else
UNP_GLOBAL_RLOCK();
switch (so->so_type) {
case SOCK_DGRAM:
{
const struct sockaddr *from;
unp2 = unp->unp_conn;
if (nam != NULL) {
UNP_GLOBAL_WLOCK_ASSERT();
if (unp2 != NULL) {
error = EISCONN;
break;
}
error = unp_connect(so, nam, td);
if (error)
break;
unp2 = unp->unp_conn;
}
/*
* Because connect() and send() are non-atomic in a sendto()
* with a target address, it's possible that the socket will
* have disconnected before the send() can run. In that case
* return the slightly counter-intuitive but otherwise
* correct error that the socket is not connected.
*/
if (unp2 == NULL) {
error = ENOTCONN;
break;
}
/* Lockless read. */
if (unp2->unp_flags & UNP_WANTCRED)
control = unp_addsockcred(td, control);
UNP_PCB_LOCK(unp);
if (unp->unp_addr != NULL)
from = (struct sockaddr *)unp->unp_addr;
else
from = &sun_noname;
so2 = unp2->unp_socket;
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_GLOBAL_WLOCK_ASSERT();
UNP_PCB_LOCK(unp2);
unp_disconnect(unp, unp2);
UNP_PCB_UNLOCK(unp2);
}
UNP_PCB_UNLOCK(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) {
UNP_GLOBAL_WLOCK_ASSERT();
error = unp_connect(so, nam, td);
if (error)
break; /* XXX */
} else {
error = ENOTCONN;
break;
}
}
/* Lockless read. */
if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
error = EPIPE;
break;
}
/*
* Because connect() and send() are non-atomic in a sendto()
* with a target address, it's possible that the socket will
* have disconnected before the send() can run. In that case
* return the slightly counter-intuitive but otherwise
* correct error that the socket is not connected.
*
* Locking here must be done carefully: the global lock
* prevents interconnections between unpcbs from changing, so
* we can traverse from unp to unp2 without acquiring unp's
* lock. Socket buffer locks follow unpcb locks, so we can
* acquire both remote and lock socket buffer locks.
*/
unp2 = unp->unp_conn;
if (unp2 == NULL) {
error = ENOTCONN;
break;
}
so2 = unp2->unp_socket;
UNP_PCB_LOCK(unp2);
SOCKBUF_LOCK(&so2->so_rcv);
if (unp2->unp_flags & UNP_WANTCRED) {
/*
* Credentials are passed only once on SOCK_STREAM.
*/
unp2->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);
mbcnt = so2->so_rcv.sb_mbcnt - unp2->unp_mbcnt;
unp2->unp_mbcnt = so2->so_rcv.sb_mbcnt;
sbcc = so2->so_rcv.sb_cc;
sorwakeup_locked(so2);
SOCKBUF_LOCK(&so->so_snd);
newhiwat = so->so_snd.sb_hiwat - (sbcc - unp2->unp_cc);
(void)chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.sb_hiwat,
newhiwat, RLIM_INFINITY);
so->so_snd.sb_mbmax -= mbcnt;
SOCKBUF_UNLOCK(&so->so_snd);
unp2->unp_cc = sbcc;
UNP_PCB_UNLOCK(unp2);
m = NULL;
break;
default:
panic("uipc_send unknown socktype");
}
/*
* SEND_EOF is equivalent to a SEND followed by a SHUTDOWN.
*/
if (flags & PRUS_EOF) {
UNP_PCB_LOCK(unp);
socantsendmore(so);
unp_shutdown(unp);
UNP_PCB_UNLOCK(unp);
}
if ((nam != NULL) || (flags & PRUS_EOF))
UNP_GLOBAL_WUNLOCK();
else
UNP_GLOBAL_RUNLOCK();
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, *unp2;
struct socket *so2;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_sense: unp == NULL"));
sb->st_blksize = so->so_snd.sb_hiwat;
UNP_GLOBAL_RLOCK();
UNP_PCB_LOCK(unp);
unp2 = unp->unp_conn;
if (so->so_type == SOCK_STREAM && unp2 != NULL) {
so2 = unp2->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_PCB_UNLOCK(unp);
UNP_GLOBAL_RUNLOCK();
return (0);
}
static int
uipc_shutdown(struct socket *so)
{
struct unpcb *unp;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_shutdown: unp == NULL"));
UNP_GLOBAL_WLOCK();
UNP_PCB_LOCK(unp);
socantsendmore(so);
unp_shutdown(unp);
UNP_PCB_UNLOCK(unp);
UNP_GLOBAL_WUNLOCK();
return (0);
}
static int
uipc_sockaddr(struct socket *so, struct sockaddr **nam)
{
struct unpcb *unp;
const struct sockaddr *sa;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_sockaddr: unp == NULL"));
*nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
UNP_PCB_LOCK(unp);
if (unp->unp_addr != NULL)
sa = (struct sockaddr *) unp->unp_addr;
else
sa = &sun_noname;
bcopy(sa, *nam, sa->sa_len);
UNP_PCB_UNLOCK(unp);
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_close = uipc_close,
};
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 = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_ctloutput: unp == NULL"));
error = 0;
switch (sopt->sopt_dir) {
case SOPT_GET:
switch (sopt->sopt_name) {
case LOCAL_PEERCRED:
UNP_PCB_LOCK(unp);
if (unp->unp_flags & UNP_HAVEPC)
xu = unp->unp_peercred;
else {
if (so->so_type == SOCK_STREAM)
error = ENOTCONN;
else
error = EINVAL;
}
UNP_PCB_UNLOCK(unp);
if (error == 0)
error = sooptcopyout(sopt, &xu, sizeof(xu));
break;
case LOCAL_CREDS:
/* Unocked read. */
optval = unp->unp_flags & UNP_WANTCRED ? 1 : 0;
error = sooptcopyout(sopt, &optval, sizeof(optval));
break;
case LOCAL_CONNWAIT:
/* Unocked read. */
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) do { \
UNP_PCB_LOCK(unp); \
if (optval) \
unp->unp_flags |= bit; \
else \
unp->unp_flags &= ~bit; \
UNP_PCB_UNLOCK(unp); \
} while (0)
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;
}
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, vfslocked;
struct nameidata nd;
char buf[SOCK_MAXADDRLEN];
struct sockaddr *sa;
UNP_GLOBAL_WLOCK_ASSERT();
UNP_GLOBAL_WUNLOCK();
unp = sotounpcb(so);
KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
len = nam->sa_len - offsetof(struct sockaddr_un, sun_path);
if (len <= 0)
return (EINVAL);
strlcpy(buf, soun->sun_path, len + 1);
UNP_PCB_LOCK(unp);
if (unp->unp_flags & UNP_CONNECTING) {
UNP_PCB_UNLOCK(unp);
return (EALREADY);
}
unp->unp_flags |= UNP_CONNECTING;
UNP_PCB_UNLOCK(unp);
sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
NDINIT(&nd, LOOKUP, MPSAFE | FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf,
td);
error = namei(&nd);
if (error)
vp = NULL;
else
vp = nd.ni_vp;
ASSERT_VOP_LOCKED(vp, "unp_connect");
vfslocked = NDHASGIANT(&nd);
NDFREE(&nd, NDF_ONLY_PNBUF);
if (error)
goto bad;
if (vp->v_type != VSOCK) {
error = ENOTSOCK;
goto bad;
}
#ifdef MAC
error = mac_check_vnode_open(td->td_ucred, vp, VWRITE | VREAD);
if (error)
goto bad;
#endif
error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td);
if (error)
goto bad;
VFS_UNLOCK_GIANT(vfslocked);
unp = sotounpcb(so);
KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
/*
* Lock global lock for two reasons: make sure v_socket is stable,
* and to protect simultaneous locking of multiple pcbs.
*/
UNP_GLOBAL_WLOCK();
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) {
/*
* We can't drop the global lock here or 'so2' may
* become invalid. As a result, we need to handle
* possibly lock recursion in uipc_attach.
*/
so3 = sonewconn(so2, 0);
} else
so3 = NULL;
if (so3 == NULL) {
error = ECONNREFUSED;
goto bad2;
}
unp = sotounpcb(so);
unp2 = sotounpcb(so2);
unp3 = sotounpcb(so3);
UNP_PCB_LOCK(unp);
UNP_PCB_LOCK(unp2);
UNP_PCB_LOCK(unp3);
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(); uipc_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;
if (unp2->unp_flags & UNP_WANTCRED)
unp3->unp_flags |= UNP_WANTCRED;
UNP_PCB_UNLOCK(unp3);
UNP_PCB_UNLOCK(unp2);
UNP_PCB_UNLOCK(unp);
#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;
}
unp = sotounpcb(so);
KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
unp2 = sotounpcb(so2);
KASSERT(unp2 != NULL, ("unp_connect: unp2 == NULL"));
UNP_PCB_LOCK(unp);
UNP_PCB_LOCK(unp2);
error = unp_connect2(so, so2, PRU_CONNECT);
UNP_PCB_UNLOCK(unp2);
UNP_PCB_UNLOCK(unp);
bad2:
UNP_GLOBAL_WUNLOCK();
if (vfslocked)
/*
* Giant has been previously acquired. This means filesystem
* isn't MPSAFE. Do it once again.
*/
mtx_lock(&Giant);
bad:
if (vp != NULL)
vput(vp);
VFS_UNLOCK_GIANT(vfslocked);
free(sa, M_SONAME);
UNP_GLOBAL_WLOCK();
UNP_PCB_LOCK(unp);
unp->unp_flags &= ~UNP_CONNECTING;
UNP_PCB_UNLOCK(unp);
return (error);
}
static int
unp_connect2(struct socket *so, struct socket *so2, int req)
{
struct unpcb *unp;
struct unpcb *unp2;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("unp_connect2: unp == NULL"));
unp2 = sotounpcb(so2);
KASSERT(unp2 != NULL, ("unp_connect2: unp2 == NULL"));
UNP_GLOBAL_WLOCK_ASSERT();
UNP_PCB_LOCK_ASSERT(unp);
UNP_PCB_LOCK_ASSERT(unp2);
if (so2->so_type != so->so_type)
return (EPROTOTYPE);
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)
{
struct socket *so;
KASSERT(unp2 != NULL, ("unp_disconnect: unp2 == NULL"));
UNP_GLOBAL_WLOCK_ASSERT();
UNP_PCB_LOCK_ASSERT(unp);
UNP_PCB_LOCK_ASSERT(unp2);
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;
}
}
/*
* unp_pcblist() walks the global list of struct unpcb's to generate a
* pointer list, bumping the refcount on each unpcb. It then copies them out
* sequentially, validating the generation number on each to see if it has
* been detached. All of this is necessary because copyout() may sleep on
* disk I/O.
*/
static int
unp_pcblist(SYSCTL_HANDLER_ARGS)
{
int error, i, n;
int freeunp;
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_GLOBAL_RLOCK();
gencnt = unp_gencnt;
n = unp_count;
UNP_GLOBAL_RUNLOCK();
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_GLOBAL_RLOCK();
for (unp = LIST_FIRST(head), i = 0; unp && i < n;
unp = LIST_NEXT(unp, unp_link)) {
UNP_PCB_LOCK(unp);
if (unp->unp_gencnt <= gencnt) {
if (cr_cansee(req->td->td_ucred,
unp->unp_socket->so_cred)) {
UNP_PCB_UNLOCK(unp);
continue;
}
unp_list[i++] = unp;
unp->unp_refcount++;
}
UNP_PCB_UNLOCK(unp);
}
UNP_GLOBAL_RUNLOCK();
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];
UNP_PCB_LOCK(unp);
unp->unp_refcount--;
if (unp->unp_refcount != 0 && 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);
UNP_PCB_UNLOCK(unp);
error = SYSCTL_OUT(req, xu, sizeof *xu);
} else {
freeunp = (unp->unp_refcount == 0);
UNP_PCB_UNLOCK(unp);
if (freeunp) {
UNP_PCB_LOCK_DESTROY(unp);
uma_zfree(unp_zone, unp);
}
}
}
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 unpcb *unp2;
struct socket *so;
UNP_GLOBAL_WLOCK_ASSERT();
UNP_PCB_LOCK_ASSERT(unp);
unp2 = unp->unp_conn;
if (unp->unp_socket->so_type == SOCK_STREAM && unp2 != NULL) {
so = unp2->unp_socket;
if (so != NULL)
socantrcvmore(so);
}
}
static void
unp_drop(struct unpcb *unp, int errno)
{
struct socket *so = unp->unp_socket;
struct unpcb *unp2;
UNP_GLOBAL_WLOCK_ASSERT();
UNP_PCB_LOCK_ASSERT(unp);
so->so_error = errno;
unp2 = unp->unp_conn;
if (unp2 == NULL)
return;
UNP_PCB_LOCK(unp2);
unp_disconnect(unp, unp2);
UNP_PCB_UNLOCK(unp2);
}
static void
unp_freerights(struct file **rp, int fdcount)
{
int i;
struct file *fp;
for (i = 0; i < fdcount; i++) {
/*
* 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.
*/
fp = *rp;
*rp++ = NULL;
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_GLOBAL_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_XLOCK(td->td_proc->p_fd);
/* if the new FD's will not fit free them. */
if (!fdavail(td, newfds)) {
FILEDESC_XUNLOCK(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_XUNLOCK(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_XUNLOCK(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);
}
static void
unp_zone_change(void *tag)
{
uma_zone_set_max(unp_zone, maxsockets);
}
void
unp_init(void)
{
unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL,
NULL, NULL, UMA_ALIGN_PTR, 0);
if (unp_zone == NULL)
panic("unp_init");
uma_zone_set_max(unp_zone, maxsockets);
EVENTHANDLER_REGISTER(maxsockets_change, unp_zone_change,
NULL, EVENTHANDLER_PRI_ANY);
LIST_INIT(&unp_dhead);
LIST_INIT(&unp_shead);
TASK_INIT(&unp_gc_task, 0, unp_gc, NULL);
UNP_GLOBAL_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_GLOBAL_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_SLOCK(fdescp);
for (i = 0; i < oldfds; i++) {
fd = *fdp++;
if ((unsigned)fd >= fdescp->fd_nfiles ||
fdescp->fd_ofiles[fd] == NULL) {
FILEDESC_SUNLOCK(fdescp);
error = EBADF;
goto out;
}
fp = fdescp->fd_ofiles[fd];
if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) {
FILEDESC_SUNLOCK(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_SUNLOCK(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_SUNLOCK(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);
}
static struct mbuf *
unp_addsockcred(struct thread *td, struct mbuf *control)
{
struct mbuf *m, *n, *n_prev;
struct sockcred *sc;
const struct cmsghdr *cm;
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);
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];
/*
* Unlink SCM_CREDS control messages (struct cmsgcred), since just
* created SCM_CREDS control message (struct sockcred) has another
* format.
*/
if (control != NULL)
for (n = control, n_prev = NULL; n != NULL;) {
cm = mtod(n, struct cmsghdr *);
if (cm->cmsg_level == SOL_SOCKET &&
cm->cmsg_type == SCM_CREDS) {
if (n_prev == NULL)
control = n->m_next;
else
n_prev->m_next = n->m_next;
n = m_free(n);
} else {
n_prev = n;
n = n->m_next;
}
}
/* Prepend it to the head. */
m->m_next = control;
return (m);
}
/*
* 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 deferred 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 to process it this
* time and un-mark it.
*/
if (fp->f_gcflag & FDEFER) {
fp->f_gcflag &= ~FDEFER;
unp_defer--;
} else {
/*
* If it's not deferred, 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 deferred, 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;
}
if (so->so_proto->pr_domain != &localdomain ||
(so->so_proto->pr_flags & PR_RIGHTS) == 0) {
FILE_UNLOCK(fp);
continue;
}
/*
* Tell any other threads that do a subsequent
* fdrop() that we are scanning the message
* buffers.
*/
fp->f_gcflag |= FWAIT;
FILE_UNLOCK(fp);
/*
* So, Ok, it's one of our sockets and it IS
* externally accessible (or was deferred). 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);
/*
* Wake up any threads waiting in fdrop().
*/
FILE_LOCK(fp);
fp->f_gcflag &= ~FWAIT;
wakeup(&fp->f_gcflag);
FILE_UNLOCK(fp);
}
} 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 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)
{
/* XXXRW: Should probably assert file list lock here. */
if (fp->f_gcflag & FMARK)
return;
unp_defer++;
fp->f_gcflag |= (FMARK|FDEFER);
}
static void
unp_discard(struct file *fp)
{
UNP_GLOBAL_WLOCK();
FILE_LOCK(fp);
fp->f_msgcount--;
unp_rights--;
FILE_UNLOCK(fp);
UNP_GLOBAL_WUNLOCK();
(void) closef(fp, (struct thread *)NULL);
}
#ifdef DDB
static void
db_print_indent(int indent)
{
int i;
for (i = 0; i < indent; i++)
db_printf(" ");
}
static void
db_print_unpflags(int unp_flags)
{
int comma;
comma = 0;
if (unp_flags & UNP_HAVEPC) {
db_printf("%sUNP_HAVEPC", comma ? ", " : "");
comma = 1;
}
if (unp_flags & UNP_HAVEPCCACHED) {
db_printf("%sUNP_HAVEPCCACHED", comma ? ", " : "");
comma = 1;
}
if (unp_flags & UNP_WANTCRED) {
db_printf("%sUNP_WANTCRED", comma ? ", " : "");
comma = 1;
}
if (unp_flags & UNP_CONNWAIT) {
db_printf("%sUNP_CONNWAIT", comma ? ", " : "");
comma = 1;
}
if (unp_flags & UNP_CONNECTING) {
db_printf("%sUNP_CONNECTING", comma ? ", " : "");
comma = 1;
}
if (unp_flags & UNP_BINDING) {
db_printf("%sUNP_BINDING", comma ? ", " : "");
comma = 1;
}
}
static void
db_print_xucred(int indent, struct xucred *xu)
{
int comma, i;
db_print_indent(indent);
db_printf("cr_version: %u cr_uid: %u cr_ngroups: %d\n",
xu->cr_version, xu->cr_uid, xu->cr_ngroups);
db_print_indent(indent);
db_printf("cr_groups: ");
comma = 0;
for (i = 0; i < xu->cr_ngroups; i++) {
db_printf("%s%u", comma ? ", " : "", xu->cr_groups[i]);
comma = 1;
}
db_printf("\n");
}
static void
db_print_unprefs(int indent, struct unp_head *uh)
{
struct unpcb *unp;
int counter;
counter = 0;
LIST_FOREACH(unp, uh, unp_reflink) {
if (counter % 4 == 0)
db_print_indent(indent);
db_printf("%p ", unp);
if (counter % 4 == 3)
db_printf("\n");
counter++;
}
if (counter != 0 && counter % 4 != 0)
db_printf("\n");
}
DB_SHOW_COMMAND(unpcb, db_show_unpcb)
{
struct unpcb *unp;
if (!have_addr) {
db_printf("usage: show unpcb <addr>\n");
return;
}
unp = (struct unpcb *)addr;
db_printf("unp_socket: %p unp_vnode: %p\n", unp->unp_socket,
unp->unp_vnode);
db_printf("unp_ino: %d unp_conn: %p\n", unp->unp_ino,
unp->unp_conn);
db_printf("unp_refs:\n");
db_print_unprefs(2, &unp->unp_refs);
/* XXXRW: Would be nice to print the full address, if any. */
db_printf("unp_addr: %p\n", unp->unp_addr);
db_printf("unp_cc: %d unp_mbcnt: %d unp_gencnt: %llu\n",
unp->unp_cc, unp->unp_mbcnt,
(unsigned long long)unp->unp_gencnt);
db_printf("unp_flags: %x (", unp->unp_flags);
db_print_unpflags(unp->unp_flags);
db_printf(")\n");
db_printf("unp_peercred:\n");
db_print_xucred(2, &unp->unp_peercred);
db_printf("unp_refcount: %u\n", unp->unp_refcount);
}
#endif
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