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freebsd-dev/sys/kern/uipc_usrreq.c
Jason A. Harmening a9aa06f7b1 Implement cycle-detecting garbage collector for AF_UNIX sockets 
The existing AF_UNIX socket garbage collector destroys any socket
which may potentially be in a cycle, as indicated by its file reference
count being equal to its enqueue count. However, this can produce false
positives for in-flight sockets which aren't part of a cycle but are
part of one or more SCM_RIGHTS mssages and which have been closed
on the sending side. If the garbage collector happens to run at
exactly the wrong time, destruction of these sockets will render them
unusable on the receiving side, such that no previously-written data
may be read.

This change rewrites the garbage collector to precisely detect cycles:

1. The existing check of msgcount==f_count is still used to determine
   whether the socket is potentially in a cycle.
2. The socket is now placed on a local "dead list", which is used to
   reduce iteration time (and therefore contention on the global
   unp_link_rwlock).
3. The first pass through the dead list removes each potentially-dead
   socket's outgoing references from the graph of potentially-dead
   sockets, using a gc-specific copy of the original reference count.
4. The second series of passes through the dead list removes from the
   list any socket whose remaining gc refcount is non-zero, as this
   indicates the socket is actually accessible outside of any possible
   cycle.  Iteration is repeated until no further sockets are removed
   from the dead list.
5. Sockets remaining in the dead list are destroyed as before.

PR:		227285
Submitted by:	jan.kokemueller@gmail.com (prior version)
Reviewed by:	markj
Differential Revision:	https://reviews.freebsd.org/D23142
2020-01-25 08:57:26 +00:00

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California. All Rights Reserved.
* Copyright (c) 2004-2009 Robert N. M. Watson All Rights Reserved.
* Copyright (c) 2018 Matthew Macy
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* 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:
* RDM
* rethink name space problems
* need a proper out-of-band
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/capsicum.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/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/queue.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>
#include <net/vnet.h>
#ifdef DDB
#include <ddb/ddb.h>
#endif
#include <security/mac/mac_framework.h>
#include <vm/uma.h>
MALLOC_DECLARE(M_FILECAPS);
/*
* Locking key:
* (l) Locked using list lock
* (g) Locked using linkage lock
*/
static uma_zone_t unp_zone;
static unp_gen_t unp_gencnt; /* (l) */
static u_int unp_count; /* (l) Count of local sockets. */
static ino_t unp_ino; /* Prototype for fake inode numbers. */
static int unp_rights; /* (g) File descriptors in flight. */
static struct unp_head unp_shead; /* (l) List of stream sockets. */
static struct unp_head unp_dhead; /* (l) List of datagram sockets. */
static struct unp_head unp_sphead; /* (l) List of seqpacket sockets. */
struct unp_defer {
SLIST_ENTRY(unp_defer) ud_link;
struct file *ud_fp;
};
static SLIST_HEAD(, unp_defer) unp_defers;
static int unp_defers_count;
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 timeout_task unp_gc_task;
/*
* The close of unix domain sockets attached as SCM_RIGHTS is
* postponed to the taskqueue, to avoid arbitrary recursion depth.
* The attached sockets might have another sockets attached.
*/
static struct task unp_defer_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;
static u_long unpsp_sendspace = PIPSIZ; /* really max datagram size */
static u_long unpsp_recvspace = PIPSIZ;
static SYSCTL_NODE(_net, PF_LOCAL, local, CTLFLAG_RW, 0, "Local domain");
static SYSCTL_NODE(_net_local, SOCK_STREAM, stream, CTLFLAG_RW, 0,
"SOCK_STREAM");
static SYSCTL_NODE(_net_local, SOCK_DGRAM, dgram, CTLFLAG_RW, 0, "SOCK_DGRAM");
static SYSCTL_NODE(_net_local, SOCK_SEQPACKET, seqpacket, CTLFLAG_RW, 0,
"SOCK_SEQPACKET");
SYSCTL_ULONG(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW,
&unpst_sendspace, 0, "Default stream send space.");
SYSCTL_ULONG(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW,
&unpst_recvspace, 0, "Default stream receive space.");
SYSCTL_ULONG(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW,
&unpdg_sendspace, 0, "Default datagram send space.");
SYSCTL_ULONG(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW,
&unpdg_recvspace, 0, "Default datagram receive space.");
SYSCTL_ULONG(_net_local_seqpacket, OID_AUTO, maxseqpacket, CTLFLAG_RW,
&unpsp_sendspace, 0, "Default seqpacket send space.");
SYSCTL_ULONG(_net_local_seqpacket, OID_AUTO, recvspace, CTLFLAG_RW,
&unpsp_recvspace, 0, "Default seqpacket receive space.");
SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0,
"File descriptors in flight.");
SYSCTL_INT(_net_local, OID_AUTO, deferred, CTLFLAG_RD,
&unp_defers_count, 0,
"File descriptors deferred to taskqueue for close.");
/*
* Locking and synchronization:
*
* Three types of locks exist in the local domain socket implementation: a
* a global linkage rwlock, the mtxpool lock, and per-unpcb mutexes.
* The linkage lock protects the socket count, global generation number,
* and stream/datagram global lists.
*
* The mtxpool lock protects the vnode from being modified while referenced.
* Lock ordering requires that it be acquired before any unpcb locks.
*
* The unpcb lock (unp_mtx) protects all fields in the unpcb. Of particular
* note is that this includes the unp_conn field. So long as the unpcb lock
* is held the reference to the unpcb pointed to by unp_conn is valid. If we
* require that the unpcb pointed to by unp_conn remain live in cases where
* we need to drop the unp_mtx as when we need to acquire the lock for a
* second unpcb the caller must first acquire an additional reference on the
* second unpcb and then revalidate any state (typically check that unp_conn
* is non-NULL) upon requiring the initial unpcb lock. The lock ordering
* between unpcbs is the conventional ascending address order. Two helper
* routines exist for this:
*
* - unp_pcb_lock2(unp, unp2) - which just acquires the two locks in the
* safe ordering.
*
* - unp_pcb_owned_lock2(unp, unp2, freed) - the lock for unp is held
* when called. If unp is unlocked and unp2 is subsequently freed
* freed will be set to 1.
*
* The helper routines for references are:
*
* - unp_pcb_hold(unp): Can be called any time we currently hold a valid
* reference to unp.
*
* - unp_pcb_rele(unp): The caller must hold the unp lock. If we are
* releasing the last reference, detach must have been called thus
* unp->unp_socket be NULL.
*
* 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 to hold a lock on unp_conn to guarantee
* that detach is not run clearing unp_socket.
*
* 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_link_rwlock;
static struct mtx unp_defers_lock;
#define UNP_LINK_LOCK_INIT() rw_init(&unp_link_rwlock, \
"unp_link_rwlock")
#define UNP_LINK_LOCK_ASSERT() rw_assert(&unp_link_rwlock, \
RA_LOCKED)
#define UNP_LINK_UNLOCK_ASSERT() rw_assert(&unp_link_rwlock, \
RA_UNLOCKED)
#define UNP_LINK_RLOCK() rw_rlock(&unp_link_rwlock)
#define UNP_LINK_RUNLOCK() rw_runlock(&unp_link_rwlock)
#define UNP_LINK_WLOCK() rw_wlock(&unp_link_rwlock)
#define UNP_LINK_WUNLOCK() rw_wunlock(&unp_link_rwlock)
#define UNP_LINK_WLOCK_ASSERT() rw_assert(&unp_link_rwlock, \
RA_WLOCKED)
#define UNP_LINK_WOWNED() rw_wowned(&unp_link_rwlock)
#define UNP_DEFERRED_LOCK_INIT() mtx_init(&unp_defers_lock, \
"unp_defer", NULL, MTX_DEF)
#define UNP_DEFERRED_LOCK() mtx_lock(&unp_defers_lock)
#define UNP_DEFERRED_UNLOCK() mtx_unlock(&unp_defers_lock)
#define UNP_REF_LIST_LOCK() UNP_DEFERRED_LOCK();
#define UNP_REF_LIST_UNLOCK() UNP_DEFERRED_UNLOCK();
#define UNP_PCB_LOCK_INIT(unp) mtx_init(&(unp)->unp_mtx, \
"unp", "unp", \
MTX_DUPOK|MTX_DEF)
#define UNP_PCB_LOCK_DESTROY(unp) mtx_destroy(&(unp)->unp_mtx)
#define UNP_PCB_LOCK(unp) mtx_lock(&(unp)->unp_mtx)
#define UNP_PCB_TRYLOCK(unp) mtx_trylock(&(unp)->unp_mtx)
#define UNP_PCB_UNLOCK(unp) mtx_unlock(&(unp)->unp_mtx)
#define UNP_PCB_OWNED(unp) mtx_owned(&(unp)->unp_mtx)
#define UNP_PCB_LOCK_ASSERT(unp) mtx_assert(&(unp)->unp_mtx, MA_OWNED)
#define UNP_PCB_UNLOCK_ASSERT(unp) mtx_assert(&(unp)->unp_mtx, MA_NOTOWNED)
static int uipc_connect2(struct socket *, struct socket *);
static int uipc_ctloutput(struct socket *, struct sockopt *);
static int unp_connect(struct socket *, struct sockaddr *,
struct thread *);
static int unp_connectat(int, 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_dispose(struct socket *so);
static void unp_dispose_mbuf(struct mbuf *);
static void unp_shutdown(struct unpcb *);
static void unp_drop(struct unpcb *);
static void unp_gc(__unused void *, int);
static void unp_scan(struct mbuf *, void (*)(struct filedescent **, int));
static void unp_discard(struct file *);
static void unp_freerights(struct filedescent **, int);
static void unp_init(void);
static int unp_internalize(struct mbuf **, struct thread *);
static void unp_internalize_fp(struct file *);
static int unp_externalize(struct mbuf *, struct mbuf **, int);
static int unp_externalize_fp(struct file *);
static struct mbuf *unp_addsockcred(struct thread *, struct mbuf *);
static void unp_process_defers(void * __unused, int);
static void
unp_pcb_hold(struct unpcb *unp)
{
MPASS(unp->unp_refcount);
refcount_acquire(&unp->unp_refcount);
}
static int
unp_pcb_rele(struct unpcb *unp)
{
int freed;
UNP_PCB_LOCK_ASSERT(unp);
MPASS(unp->unp_refcount);
if ((freed = refcount_release(&unp->unp_refcount))) {
/* we got here with having detached? */
MPASS(unp->unp_socket == NULL);
UNP_PCB_UNLOCK(unp);
UNP_PCB_LOCK_DESTROY(unp);
uma_zfree(unp_zone, unp);
}
return (freed);
}
static void
unp_pcb_lock2(struct unpcb *unp, struct unpcb *unp2)
{
MPASS(unp != unp2);
UNP_PCB_UNLOCK_ASSERT(unp);
UNP_PCB_UNLOCK_ASSERT(unp2);
if ((uintptr_t)unp2 > (uintptr_t)unp) {
UNP_PCB_LOCK(unp);
UNP_PCB_LOCK(unp2);
} else {
UNP_PCB_LOCK(unp2);
UNP_PCB_LOCK(unp);
}
}
static __noinline void
unp_pcb_owned_lock2_slowpath(struct unpcb *unp, struct unpcb **unp2p,
int *freed)
{
struct unpcb *unp2;
unp2 = *unp2p;
unp_pcb_hold(unp2);
UNP_PCB_UNLOCK(unp);
UNP_PCB_LOCK(unp2);
UNP_PCB_LOCK(unp);
*freed = unp_pcb_rele(unp2);
if (*freed)
*unp2p = NULL;
}
#define unp_pcb_owned_lock2(unp, unp2, freed) do { \
freed = 0; \
UNP_PCB_LOCK_ASSERT(unp); \
UNP_PCB_UNLOCK_ASSERT(unp2); \
MPASS((unp) != (unp2)); \
if (__predict_true(UNP_PCB_TRYLOCK(unp2))) \
break; \
else if ((uintptr_t)(unp2) > (uintptr_t)(unp)) \
UNP_PCB_LOCK(unp2); \
else \
unp_pcb_owned_lock2_slowpath((unp), &(unp2), &freed); \
} while (0)
/*
* Definitions of protocols supported in the LOCAL domain.
*/
static struct domain localdomain;
static struct pr_usrreqs uipc_usrreqs_dgram, uipc_usrreqs_stream;
static struct pr_usrreqs uipc_usrreqs_seqpacket;
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_stream
},
{
.pr_type = SOCK_DGRAM,
.pr_domain = &localdomain,
.pr_flags = PR_ATOMIC|PR_ADDR|PR_RIGHTS,
.pr_ctloutput = &uipc_ctloutput,
.pr_usrreqs = &uipc_usrreqs_dgram
},
{
.pr_type = SOCK_SEQPACKET,
.pr_domain = &localdomain,
/*
* XXXRW: For now, PR_ADDR because soreceive will bump into them
* due to our use of sbappendaddr. A new sbappend variants is needed
* that supports both atomic record writes and control data.
*/
.pr_flags = PR_ADDR|PR_ATOMIC|PR_CONNREQUIRED|PR_WANTRCVD|
PR_RIGHTS,
.pr_ctloutput = &uipc_ctloutput,
.pr_usrreqs = &uipc_usrreqs_seqpacket,
},
};
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[nitems(localsw)]
};
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_PCB_UNLOCK_ASSERT(unp);
UNP_PCB_LOCK(unp);
unp2 = unp->unp_conn;
if (unp2 != NULL) {
unp_pcb_hold(unp2);
UNP_PCB_UNLOCK(unp);
unp_drop(unp2);
} else
UNP_PCB_UNLOCK(unp);
}
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_LINK_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_LINK_RUNLOCK();
return (0);
}
static int
uipc_attach(struct socket *so, int proto, struct thread *td)
{
u_long sendspace, recvspace;
struct unpcb *unp;
int error;
bool 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;
case SOCK_SEQPACKET:
sendspace = unpsp_sendspace;
recvspace = unpsp_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;
if (so->so_listen != NULL)
unp->unp_flags |= UNP_NASCENT;
if ((locked = UNP_LINK_WOWNED()) == false)
UNP_LINK_WLOCK();
unp->unp_gencnt = ++unp_gencnt;
unp->unp_ino = ++unp_ino;
unp_count++;
switch (so->so_type) {
case SOCK_STREAM:
LIST_INSERT_HEAD(&unp_shead, unp, unp_link);
break;
case SOCK_DGRAM:
LIST_INSERT_HEAD(&unp_dhead, unp, unp_link);
break;
case SOCK_SEQPACKET:
LIST_INSERT_HEAD(&unp_sphead, unp, unp_link);
break;
default:
panic("uipc_attach");
}
if (locked == false)
UNP_LINK_WUNLOCK();
return (0);
}
static int
uipc_bindat(int fd, struct socket *so, struct sockaddr *nam, struct thread *td)
{
struct sockaddr_un *soun = (struct sockaddr_un *)nam;
struct vattr vattr;
int error, namelen;
struct nameidata nd;
struct unpcb *unp;
struct vnode *vp;
struct mount *mp;
cap_rights_t rights;
char *buf;
if (nam->sa_family != AF_UNIX)
return (EAFNOSUPPORT);
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_bind: unp == NULL"));
if (soun->sun_len > sizeof(struct sockaddr_un))
return (EINVAL);
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);
bcopy(soun->sun_path, buf, namelen);
buf[namelen] = 0;
restart:
NDINIT_ATRIGHTS(&nd, CREATE, NOFOLLOW | LOCKPARENT | SAVENAME | NOCACHE,
UIO_SYSSPACE, buf, fd, cap_rights_init(&rights, CAP_BINDAT), td);
/* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */
error = namei(&nd);
if (error)
goto error;
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 error;
}
error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH);
if (error)
goto error;
goto restart;
}
VATTR_NULL(&vattr);
vattr.va_type = VSOCK;
vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask);
#ifdef MAC
error = mac_vnode_check_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd,
&vattr);
#endif
if (error == 0)
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_PCB_LOCK(unp);
VOP_UNP_BIND(vp, unp);
unp->unp_vnode = vp;
unp->unp_addr = soun;
unp->unp_flags &= ~UNP_BINDING;
UNP_PCB_UNLOCK(unp);
VOP_UNLOCK(vp);
vn_finished_write(mp);
free(buf, M_TEMP);
return (0);
error:
UNP_PCB_LOCK(unp);
unp->unp_flags &= ~UNP_BINDING;
UNP_PCB_UNLOCK(unp);
free(buf, M_TEMP);
return (error);
}
static int
uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
{
return (uipc_bindat(AT_FDCWD, so, nam, td));
}
static int
uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
{
int error;
KASSERT(td == curthread, ("uipc_connect: td != curthread"));
error = unp_connect(so, nam, td);
return (error);
}
static int
uipc_connectat(int fd, struct socket *so, struct sockaddr *nam,
struct thread *td)
{
int error;
KASSERT(td == curthread, ("uipc_connectat: td != curthread"));
error = unp_connectat(fd, so, nam, td);
return (error);
}
static void
uipc_close(struct socket *so)
{
struct unpcb *unp, *unp2;
struct vnode *vp = NULL;
struct mtx *vplock;
int freed;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_close: unp == NULL"));
vplock = NULL;
if ((vp = unp->unp_vnode) != NULL) {
vplock = mtx_pool_find(mtxpool_sleep, vp);
mtx_lock(vplock);
}
UNP_PCB_LOCK(unp);
if (vp && unp->unp_vnode == NULL) {
mtx_unlock(vplock);
vp = NULL;
}
if (vp != NULL) {
VOP_UNP_DETACH(vp);
unp->unp_vnode = NULL;
}
unp2 = unp->unp_conn;
unp_pcb_hold(unp);
if (__predict_false(unp == unp2)) {
unp_disconnect(unp, unp2);
} else if (unp2 != NULL) {
unp_pcb_hold(unp2);
unp_pcb_owned_lock2(unp, unp2, freed);
unp_disconnect(unp, unp2);
if (unp_pcb_rele(unp2) == 0)
UNP_PCB_UNLOCK(unp2);
}
if (unp_pcb_rele(unp) == 0)
UNP_PCB_UNLOCK(unp);
if (vp) {
mtx_unlock(vplock);
vrele(vp);
}
}
static int
uipc_connect2(struct socket *so1, struct socket *so2)
{
struct unpcb *unp, *unp2;
int error;
unp = so1->so_pcb;
KASSERT(unp != NULL, ("uipc_connect2: unp == NULL"));
unp2 = so2->so_pcb;
KASSERT(unp2 != NULL, ("uipc_connect2: unp2 == NULL"));
if (unp != unp2)
unp_pcb_lock2(unp, unp2);
else
UNP_PCB_LOCK(unp);
error = unp_connect2(so1, so2, PRU_CONNECT2);
if (unp != unp2)
UNP_PCB_UNLOCK(unp2);
UNP_PCB_UNLOCK(unp);
return (error);
}
static void
uipc_detach(struct socket *so)
{
struct unpcb *unp, *unp2;
struct mtx *vplock;
struct sockaddr_un *saved_unp_addr;
struct vnode *vp;
int freeunp, local_unp_rights;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_detach: unp == NULL"));
vp = NULL;
vplock = NULL;
local_unp_rights = 0;
UNP_LINK_WLOCK();
LIST_REMOVE(unp, unp_link);
if (unp->unp_gcflag & UNPGC_DEAD)
LIST_REMOVE(unp, unp_dead);
unp->unp_gencnt = ++unp_gencnt;
--unp_count;
UNP_LINK_WUNLOCK();
UNP_PCB_UNLOCK_ASSERT(unp);
restart:
if ((vp = unp->unp_vnode) != NULL) {
vplock = mtx_pool_find(mtxpool_sleep, vp);
mtx_lock(vplock);
}
UNP_PCB_LOCK(unp);
if (unp->unp_vnode != vp &&
unp->unp_vnode != NULL) {
if (vplock)
mtx_unlock(vplock);
UNP_PCB_UNLOCK(unp);
goto restart;
}
if ((unp->unp_flags & UNP_NASCENT) != 0) {
goto teardown;
}
if ((vp = unp->unp_vnode) != NULL) {
VOP_UNP_DETACH(vp);
unp->unp_vnode = NULL;
}
if (__predict_false(unp == unp->unp_conn)) {
unp_disconnect(unp, unp);
unp2 = NULL;
goto connect_self;
}
if ((unp2 = unp->unp_conn) != NULL) {
unp_pcb_owned_lock2(unp, unp2, freeunp);
if (freeunp)
unp2 = NULL;
}
unp_pcb_hold(unp);
if (unp2 != NULL) {
unp_pcb_hold(unp2);
unp_disconnect(unp, unp2);
if (unp_pcb_rele(unp2) == 0)
UNP_PCB_UNLOCK(unp2);
}
connect_self:
UNP_PCB_UNLOCK(unp);
UNP_REF_LIST_LOCK();
while (!LIST_EMPTY(&unp->unp_refs)) {
struct unpcb *ref = LIST_FIRST(&unp->unp_refs);
unp_pcb_hold(ref);
UNP_REF_LIST_UNLOCK();
MPASS(ref != unp);
UNP_PCB_UNLOCK_ASSERT(ref);
unp_drop(ref);
UNP_REF_LIST_LOCK();
}
UNP_REF_LIST_UNLOCK();
UNP_PCB_LOCK(unp);
freeunp = unp_pcb_rele(unp);
MPASS(freeunp == 0);
local_unp_rights = unp_rights;
teardown:
unp->unp_socket->so_pcb = NULL;
saved_unp_addr = unp->unp_addr;
unp->unp_addr = NULL;
unp->unp_socket = NULL;
freeunp = unp_pcb_rele(unp);
if (saved_unp_addr != NULL)
free(saved_unp_addr, M_SONAME);
if (!freeunp)
UNP_PCB_UNLOCK(unp);
if (vp) {
mtx_unlock(vplock);
vrele(vp);
}
if (local_unp_rights)
taskqueue_enqueue_timeout(taskqueue_thread, &unp_gc_task, -1);
}
static int
uipc_disconnect(struct socket *so)
{
struct unpcb *unp, *unp2;
int freed;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_disconnect: unp == NULL"));
UNP_PCB_LOCK(unp);
if ((unp2 = unp->unp_conn) == NULL) {
UNP_PCB_UNLOCK(unp);
return (0);
}
if (__predict_true(unp != unp2)) {
unp_pcb_owned_lock2(unp, unp2, freed);
if (__predict_false(freed)) {
UNP_PCB_UNLOCK(unp);
return (0);
}
unp_pcb_hold(unp2);
}
unp_pcb_hold(unp);
unp_disconnect(unp, unp2);
if (unp_pcb_rele(unp) == 0)
UNP_PCB_UNLOCK(unp);
if ((unp != unp2) && unp_pcb_rele(unp2) == 0)
UNP_PCB_UNLOCK(unp2);
return (0);
}
static int
uipc_listen(struct socket *so, int backlog, struct thread *td)
{
struct unpcb *unp;
int error;
if (so->so_type != SOCK_STREAM && so->so_type != SOCK_SEQPACKET)
return (EOPNOTSUPP);
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_listen: unp == NULL"));
UNP_PCB_LOCK(unp);
if (unp->unp_vnode == NULL) {
/* Already connected or not bound to an address. */
error = unp->unp_conn != NULL ? EINVAL : EDESTADDRREQ;
UNP_PCB_UNLOCK(unp);
return (error);
}
SOCK_LOCK(so);
error = solisten_proto_check(so);
if (error == 0) {
cru2xt(td, &unp->unp_peercred);
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_LINK_RLOCK();
/*
* 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 *) unp2->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_LINK_RUNLOCK();
return (0);
}
static int
uipc_rcvd(struct socket *so, int flags)
{
struct unpcb *unp, *unp2;
struct socket *so2;
u_int mbcnt, sbcc;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("%s: unp == NULL", __func__));
KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_SEQPACKET,
("%s: socktype %d", __func__, so->so_type));
/*
* 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 = sbavail(&so->so_rcv);
SOCKBUF_UNLOCK(&so->so_rcv);
/*
* There is a benign race condition at this point. If we're planning to
* clear SB_STOP, but uipc_send is called on the connected socket at
* this instant, it might add data to the sockbuf and set SB_STOP. Then
* we would erroneously clear SB_STOP below, even though the sockbuf is
* full. The race is benign because the only ill effect is to allow the
* sockbuf to exceed its size limit, and the size limits are not
* strictly guaranteed anyway.
*/
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);
if (sbcc < so2->so_snd.sb_hiwat && mbcnt < so2->so_snd.sb_mbmax)
so2->so_snd.sb_flags &= ~SB_STOP;
sowwakeup_locked(so2);
UNP_PCB_UNLOCK(unp);
return (0);
}
static int
connect_internal(struct socket *so, struct sockaddr *nam, struct thread *td)
{
int error;
struct unpcb *unp;
unp = so->so_pcb;
if (unp->unp_conn != NULL)
return (EISCONN);
error = unp_connect(so, nam, td);
if (error)
return (error);
UNP_PCB_LOCK(unp);
if (unp->unp_conn == NULL) {
UNP_PCB_UNLOCK(unp);
if (error == 0)
error = ENOTCONN;
}
return (error);
}
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;
int freed, error;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("%s: unp == NULL", __func__));
KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_DGRAM ||
so->so_type == SOCK_SEQPACKET,
("%s: socktype %d", __func__, so->so_type));
freed = error = 0;
if (flags & PRUS_OOB) {
error = EOPNOTSUPP;
goto release;
}
if (control != NULL && (error = unp_internalize(&control, td)))
goto release;
unp2 = NULL;
switch (so->so_type) {
case SOCK_DGRAM:
{
const struct sockaddr *from;
if (nam != NULL) {
/*
* We return with UNP_PCB_LOCK_HELD so we know that
* the reference is live if the pointer is valid.
*/
if ((error = connect_internal(so, nam, td)))
break;
MPASS(unp->unp_conn != NULL);
unp2 = unp->unp_conn;
} else {
UNP_PCB_LOCK(unp);
/*
* 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 = unp->unp_conn) == NULL) {
UNP_PCB_UNLOCK(unp);
error = ENOTCONN;
break;
}
}
if (__predict_false(unp == unp2)) {
if (unp->unp_socket == NULL) {
error = ENOTCONN;
break;
}
goto connect_self;
}
unp_pcb_owned_lock2(unp, unp2, freed);
if (__predict_false(freed)) {
UNP_PCB_UNLOCK(unp);
error = ENOTCONN;
break;
}
/*
* The socket referencing unp2 may have been closed
* or unp may have been disconnected if the unp lock
* was dropped to acquire unp2.
*/
if (__predict_false(unp->unp_conn == NULL) ||
unp2->unp_socket == NULL) {
UNP_PCB_UNLOCK(unp);
if (unp_pcb_rele(unp2) == 0)
UNP_PCB_UNLOCK(unp2);
error = ENOTCONN;
break;
}
connect_self:
if (unp2->unp_flags & UNP_WANTCRED)
control = unp_addsockcred(td, control);
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_disconnect(unp, unp2);
if (__predict_true(unp != unp2))
UNP_PCB_UNLOCK(unp2);
UNP_PCB_UNLOCK(unp);
break;
}
case SOCK_SEQPACKET:
case SOCK_STREAM:
if ((so->so_state & SS_ISCONNECTED) == 0) {
if (nam != NULL) {
if ((error = connect_internal(so, nam, td)))
break;
} else {
error = ENOTCONN;
break;
}
} else if ((unp2 = unp->unp_conn) == NULL) {
error = ENOTCONN;
break;
} else if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
error = EPIPE;
break;
} else {
UNP_PCB_LOCK(unp);
if ((unp2 = unp->unp_conn) == NULL) {
UNP_PCB_UNLOCK(unp);
error = ENOTCONN;
break;
}
}
unp_pcb_owned_lock2(unp, unp2, freed);
UNP_PCB_UNLOCK(unp);
if (__predict_false(freed)) {
error = ENOTCONN;
break;
}
if ((so2 = unp2->unp_socket) == NULL) {
UNP_PCB_UNLOCK(unp2);
error = ENOTCONN;
break;
}
SOCKBUF_LOCK(&so2->so_rcv);
if (unp2->unp_flags & UNP_WANTCRED) {
/*
* Credentials are passed only once on SOCK_STREAM
* and SOCK_SEQPACKET.
*/
unp2->unp_flags &= ~UNP_WANTCRED;
control = unp_addsockcred(td, control);
}
/*
* Send to paired receive port and wake up readers. Don't
* check for space available in the receive buffer if we're
* attaching ancillary data; Unix domain sockets only check
* for space in the sending sockbuf, and that check is
* performed one level up the stack. At that level we cannot
* precisely account for the amount of buffer space used
* (e.g., because control messages are not yet internalized).
*/
switch (so->so_type) {
case SOCK_STREAM:
if (control != NULL) {
sbappendcontrol_locked(&so2->so_rcv, m,
control);
control = NULL;
} else
sbappend_locked(&so2->so_rcv, m, flags);
break;
case SOCK_SEQPACKET: {
const struct sockaddr *from;
from = &sun_noname;
if (sbappendaddr_nospacecheck_locked(&so2->so_rcv,
from, m, control))
control = NULL;
break;
}
}
mbcnt = so2->so_rcv.sb_mbcnt;
sbcc = sbavail(&so2->so_rcv);
if (sbcc)
sorwakeup_locked(so2);
else
SOCKBUF_UNLOCK(&so2->so_rcv);
/*
* The PCB lock on unp2 protects the SB_STOP flag. Without it,
* it would be possible for uipc_rcvd to be called at this
* point, drain the receiving sockbuf, clear SB_STOP, and then
* we would set SB_STOP below. That could lead to an empty
* sockbuf having SB_STOP set
*/
SOCKBUF_LOCK(&so->so_snd);
if (sbcc >= so->so_snd.sb_hiwat || mbcnt >= so->so_snd.sb_mbmax)
so->so_snd.sb_flags |= SB_STOP;
SOCKBUF_UNLOCK(&so->so_snd);
UNP_PCB_UNLOCK(unp2);
m = NULL;
break;
}
/*
* PRUS_EOF is equivalent to pru_send followed by pru_shutdown.
*/
if (flags & PRUS_EOF) {
UNP_PCB_LOCK(unp);
socantsendmore(so);
unp_shutdown(unp);
UNP_PCB_UNLOCK(unp);
}
if (control != NULL && error != 0)
unp_dispose_mbuf(control);
release:
if (control != NULL)
m_freem(control);
/*
* In case of PRUS_NOTREADY, uipc_ready() is responsible
* for freeing memory.
*/
if (m != NULL && (flags & PRUS_NOTREADY) == 0)
m_freem(m);
return (error);
}
static int
uipc_ready(struct socket *so, struct mbuf *m, int count)
{
struct unpcb *unp, *unp2;
struct socket *so2;
int error;
unp = sotounpcb(so);
UNP_PCB_LOCK(unp);
if ((unp2 = unp->unp_conn) == NULL) {
UNP_PCB_UNLOCK(unp);
goto error;
}
if (unp != unp2) {
if (UNP_PCB_TRYLOCK(unp2) == 0) {
unp_pcb_hold(unp2);
UNP_PCB_UNLOCK(unp);
UNP_PCB_LOCK(unp2);
if (unp_pcb_rele(unp2))
goto error;
} else
UNP_PCB_UNLOCK(unp);
}
so2 = unp2->unp_socket;
SOCKBUF_LOCK(&so2->so_rcv);
if ((error = sbready(&so2->so_rcv, m, count)) == 0)
sorwakeup_locked(so2);
else
SOCKBUF_UNLOCK(&so2->so_rcv);
UNP_PCB_UNLOCK(unp2);
return (error);
error:
for (int i = 0; i < count; i++)
m = m_free(m);
return (ECONNRESET);
}
static int
uipc_sense(struct socket *so, struct stat *sb)
{
struct unpcb *unp;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_sense: unp == NULL"));
sb->st_blksize = so->so_snd.sb_hiwat;
sb->st_dev = NODEV;
sb->st_ino = unp->unp_ino;
return (0);
}
static int
uipc_shutdown(struct socket *so)
{
struct unpcb *unp;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("uipc_shutdown: unp == NULL"));
UNP_PCB_LOCK(unp);
socantsendmore(so);
unp_shutdown(unp);
UNP_PCB_UNLOCK(unp);
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);
}
static struct pr_usrreqs uipc_usrreqs_dgram = {
.pru_abort = uipc_abort,
.pru_accept = uipc_accept,
.pru_attach = uipc_attach,
.pru_bind = uipc_bind,
.pru_bindat = uipc_bindat,
.pru_connect = uipc_connect,
.pru_connectat = uipc_connectat,
.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_soreceive = soreceive_dgram,
.pru_close = uipc_close,
};
static struct pr_usrreqs uipc_usrreqs_seqpacket = {
.pru_abort = uipc_abort,
.pru_accept = uipc_accept,
.pru_attach = uipc_attach,
.pru_bind = uipc_bind,
.pru_bindat = uipc_bindat,
.pru_connect = uipc_connect,
.pru_connectat = uipc_connectat,
.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_soreceive = soreceive_generic, /* XXX: or...? */
.pru_close = uipc_close,
};
static struct pr_usrreqs uipc_usrreqs_stream = {
.pru_abort = uipc_abort,
.pru_accept = uipc_accept,
.pru_attach = uipc_attach,
.pru_bind = uipc_bind,
.pru_bindat = uipc_bindat,
.pru_connect = uipc_connect,
.pru_connectat = uipc_connectat,
.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_ready = uipc_ready,
.pru_sense = uipc_sense,
.pru_shutdown = uipc_shutdown,
.pru_sockaddr = uipc_sockaddr,
.pru_soreceive = soreceive_generic,
.pru_close = uipc_close,
};
static 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:
/* Unlocked read. */
optval = unp->unp_flags & UNP_WANTCRED ? 1 : 0;
error = sooptcopyout(sopt, &optval, sizeof(optval));
break;
case LOCAL_CONNWAIT:
/* Unlocked 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)
{
return (unp_connectat(AT_FDCWD, so, nam, td));
}
static int
unp_connectat(int fd, struct socket *so, struct sockaddr *nam,
struct thread *td)
{
struct sockaddr_un *soun = (struct sockaddr_un *)nam;
struct vnode *vp;
struct socket *so2;
struct unpcb *unp, *unp2, *unp3;
struct nameidata nd;
char buf[SOCK_MAXADDRLEN];
struct sockaddr *sa;
cap_rights_t rights;
int error, len, freed;
struct mtx *vplock;
if (nam->sa_family != AF_UNIX)
return (EAFNOSUPPORT);
if (nam->sa_len > sizeof(struct sockaddr_un))
return (EINVAL);
len = nam->sa_len - offsetof(struct sockaddr_un, sun_path);
if (len <= 0)
return (EINVAL);
bcopy(soun->sun_path, buf, len);
buf[len] = 0;
unp = sotounpcb(so);
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_ATRIGHTS(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF,
UIO_SYSSPACE, buf, fd, cap_rights_init(&rights, CAP_CONNECTAT), 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;
}
#ifdef MAC
error = mac_vnode_check_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;
unp = sotounpcb(so);
KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
vplock = mtx_pool_find(mtxpool_sleep, vp);
mtx_lock(vplock);
VOP_UNP_CONNECT(vp, &unp2);
if (unp2 == NULL) {
error = ECONNREFUSED;
goto bad2;
}
so2 = unp2->unp_socket;
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) {
CURVNET_SET(so2->so_vnet);
so2 = sonewconn(so2, 0);
CURVNET_RESTORE();
} else
so2 = NULL;
if (so2 == NULL) {
error = ECONNREFUSED;
goto bad2;
}
unp3 = sotounpcb(so2);
unp_pcb_lock2(unp2, 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_copy_peercred(td, unp3, unp, unp2);
UNP_PCB_UNLOCK(unp2);
unp2 = unp3;
unp_pcb_owned_lock2(unp2, unp, freed);
if (__predict_false(freed)) {
UNP_PCB_UNLOCK(unp2);
error = ECONNREFUSED;
goto bad2;
}
#ifdef MAC
mac_socketpeer_set_from_socket(so, so2);
mac_socketpeer_set_from_socket(so2, so);
#endif
} else {
if (unp == unp2)
UNP_PCB_LOCK(unp);
else
unp_pcb_lock2(unp, unp2);
}
KASSERT(unp2 != NULL && so2 != NULL && unp2->unp_socket == so2 &&
sotounpcb(so2) == unp2,
("%s: unp2 %p so2 %p", __func__, unp2, so2));
error = unp_connect2(so, so2, PRU_CONNECT);
if (unp != unp2)
UNP_PCB_UNLOCK(unp2);
UNP_PCB_UNLOCK(unp);
bad2:
mtx_unlock(vplock);
bad:
if (vp != NULL) {
vput(vp);
}
free(sa, M_SONAME);
UNP_PCB_LOCK(unp);
unp->unp_flags &= ~UNP_CONNECTING;
UNP_PCB_UNLOCK(unp);
return (error);
}
/*
* Set socket peer credentials at connection time.
*
* The client's PCB credentials are copied from its process structure. The
* server's PCB credentials are copied from the socket on which it called
* listen(2). uipc_listen cached that process's credentials at the time.
*/
void
unp_copy_peercred(struct thread *td, struct unpcb *client_unp,
struct unpcb *server_unp, struct unpcb *listen_unp)
{
cru2xt(td, &client_unp->unp_peercred);
client_unp->unp_flags |= UNP_HAVEPC;
memcpy(&server_unp->unp_peercred, &listen_unp->unp_peercred,
sizeof(server_unp->unp_peercred));
server_unp->unp_flags |= UNP_HAVEPC;
if (listen_unp->unp_flags & UNP_WANTCRED)
client_unp->unp_flags |= UNP_WANTCRED;
}
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_PCB_LOCK_ASSERT(unp);
UNP_PCB_LOCK_ASSERT(unp2);
if (so2->so_type != so->so_type)
return (EPROTOTYPE);
unp2->unp_flags &= ~UNP_NASCENT;
unp->unp_conn = unp2;
unp_pcb_hold(unp2);
unp_pcb_hold(unp);
switch (so->so_type) {
case SOCK_DGRAM:
UNP_REF_LIST_LOCK();
LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink);
UNP_REF_LIST_UNLOCK();
soisconnected(so);
break;
case SOCK_STREAM:
case SOCK_SEQPACKET:
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, *so2;
int freed __unused;
KASSERT(unp2 != NULL, ("unp_disconnect: unp2 == NULL"));
UNP_PCB_LOCK_ASSERT(unp);
UNP_PCB_LOCK_ASSERT(unp2);
if (unp->unp_conn == NULL && unp2->unp_conn == NULL)
return;
MPASS(unp->unp_conn == unp2);
unp->unp_conn = NULL;
so = unp->unp_socket;
so2 = unp2->unp_socket;
switch (unp->unp_socket->so_type) {
case SOCK_DGRAM:
UNP_REF_LIST_LOCK();
LIST_REMOVE(unp, unp_reflink);
UNP_REF_LIST_UNLOCK();
if (so) {
SOCK_LOCK(so);
so->so_state &= ~SS_ISCONNECTED;
SOCK_UNLOCK(so);
}
break;
case SOCK_STREAM:
case SOCK_SEQPACKET:
if (so)
soisdisconnected(so);
MPASS(unp2->unp_conn == unp);
unp2->unp_conn = NULL;
if (so2)
soisdisconnected(so2);
break;
}
freed = unp_pcb_rele(unp);
MPASS(freed == 0);
freed = unp_pcb_rele(unp2);
MPASS(freed == 0);
}
/*
* 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)
{
struct unpcb *unp, **unp_list;
unp_gen_t gencnt;
struct xunpgen *xug;
struct unp_head *head;
struct xunpcb *xu;
u_int i;
int error, freeunp, n;
switch ((intptr_t)arg1) {
case SOCK_STREAM:
head = &unp_shead;
break;
case SOCK_DGRAM:
head = &unp_dhead;
break;
case SOCK_SEQPACKET:
head = &unp_sphead;
break;
default:
panic("unp_pcblist: arg1 %d", (int)(intptr_t)arg1);
}
/*
* 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 | M_ZERO);
UNP_LINK_RLOCK();
gencnt = unp_gencnt;
n = unp_count;
UNP_LINK_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_LINK_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_pcb_hold(unp);
}
UNP_PCB_UNLOCK(unp);
}
UNP_LINK_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);
freeunp = unp_pcb_rele(unp);
if (freeunp == 0 && unp->unp_gencnt <= gencnt) {
xu->xu_len = sizeof *xu;
xu->xu_unpp = (uintptr_t)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);
else
bzero(&xu->xu_addr, sizeof(xu->xu_addr));
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);
else
bzero(&xu->xu_caddr, sizeof(xu->xu_caddr));
xu->unp_vnode = (uintptr_t)unp->unp_vnode;
xu->unp_conn = (uintptr_t)unp->unp_conn;
xu->xu_firstref = (uintptr_t)LIST_FIRST(&unp->unp_refs);
xu->xu_nextref = (uintptr_t)LIST_NEXT(unp, unp_reflink);
xu->unp_gencnt = unp->unp_gencnt;
sotoxsocket(unp->unp_socket, &xu->xu_socket);
UNP_PCB_UNLOCK(unp);
error = SYSCTL_OUT(req, xu, sizeof *xu);
} else if (freeunp == 0)
UNP_PCB_UNLOCK(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, CTLTYPE_OPAQUE | CTLFLAG_RD,
(void *)(intptr_t)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb",
"List of active local datagram sockets");
SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLTYPE_OPAQUE | CTLFLAG_RD,
(void *)(intptr_t)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb",
"List of active local stream sockets");
SYSCTL_PROC(_net_local_seqpacket, OID_AUTO, pcblist,
CTLTYPE_OPAQUE | CTLFLAG_RD,
(void *)(intptr_t)SOCK_SEQPACKET, 0, unp_pcblist, "S,xunpcb",
"List of active local seqpacket sockets");
static void
unp_shutdown(struct unpcb *unp)
{
struct unpcb *unp2;
struct socket *so;
UNP_PCB_LOCK_ASSERT(unp);
unp2 = unp->unp_conn;
if ((unp->unp_socket->so_type == SOCK_STREAM ||
(unp->unp_socket->so_type == SOCK_SEQPACKET)) && unp2 != NULL) {
so = unp2->unp_socket;
if (so != NULL)
socantrcvmore(so);
}
}
static void
unp_drop(struct unpcb *unp)
{
struct socket *so = unp->unp_socket;
struct unpcb *unp2;
int freed;
/*
* Regardless of whether the socket's peer dropped the connection
* with this socket by aborting or disconnecting, POSIX requires
* that ECONNRESET is returned.
*/
/* acquire a reference so that unp isn't freed from underneath us */
UNP_PCB_LOCK(unp);
if (so)
so->so_error = ECONNRESET;
unp2 = unp->unp_conn;
if (unp2 == unp) {
unp_disconnect(unp, unp2);
} else if (unp2 != NULL) {
unp_pcb_hold(unp2);
unp_pcb_owned_lock2(unp, unp2, freed);
unp_disconnect(unp, unp2);
if (unp_pcb_rele(unp2) == 0)
UNP_PCB_UNLOCK(unp2);
}
if (unp_pcb_rele(unp) == 0)
UNP_PCB_UNLOCK(unp);
}
static void
unp_freerights(struct filedescent **fdep, int fdcount)
{
struct file *fp;
int i;
KASSERT(fdcount > 0, ("%s: fdcount %d", __func__, fdcount));
for (i = 0; i < fdcount; i++) {
fp = fdep[i]->fde_file;
filecaps_free(&fdep[i]->fde_caps);
unp_discard(fp);
}
free(fdep[0], M_FILECAPS);
}
static int
unp_externalize(struct mbuf *control, struct mbuf **controlp, int flags)
{
struct thread *td = curthread; /* XXX */
struct cmsghdr *cm = mtod(control, struct cmsghdr *);
int i;
int *fdp;
struct filedesc *fdesc = td->td_proc->p_fd;
struct filedescent **fdep;
void *data;
socklen_t clen = control->m_len, datalen;
int error, newfds;
u_int newlen;
UNP_LINK_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(*fdep);
if (newfds == 0)
goto next;
fdep = data;
/* If we're not outputting the descriptors free them. */
if (error || controlp == NULL) {
unp_freerights(fdep, newfds);
goto next;
}
FILEDESC_XLOCK(fdesc);
/*
* 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(fdesc);
error = E2BIG;
unp_freerights(fdep, newfds);
goto next;
}
fdp = (int *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
if (fdallocn(td, 0, fdp, newfds) != 0) {
FILEDESC_XUNLOCK(fdesc);
error = EMSGSIZE;
unp_freerights(fdep, newfds);
m_freem(*controlp);
*controlp = NULL;
goto next;
}
for (i = 0; i < newfds; i++, fdp++) {
_finstall(fdesc, fdep[i]->fde_file, *fdp,
(flags & MSG_CMSG_CLOEXEC) != 0 ? UF_EXCLOSE : 0,
&fdep[i]->fde_caps);
unp_externalize_fp(fdep[i]->fde_file);
}
/*
* The new type indicates that the mbuf data refers to
* kernel resources that may need to be released before
* the mbuf is freed.
*/
m_chtype(*controlp, MT_EXTCONTROL);
FILEDESC_XUNLOCK(fdesc);
free(fdep[0], M_FILECAPS);
} 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);
}
static void
unp_init(void)
{
#ifdef VIMAGE
if (!IS_DEFAULT_VNET(curvnet))
return;
#endif
unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL,
NULL, NULL, UMA_ALIGN_CACHE, 0);
if (unp_zone == NULL)
panic("unp_init");
uma_zone_set_max(unp_zone, maxsockets);
uma_zone_set_warning(unp_zone, "kern.ipc.maxsockets limit reached");
EVENTHANDLER_REGISTER(maxsockets_change, unp_zone_change,
NULL, EVENTHANDLER_PRI_ANY);
LIST_INIT(&unp_dhead);
LIST_INIT(&unp_shead);
LIST_INIT(&unp_sphead);
SLIST_INIT(&unp_defers);
TIMEOUT_TASK_INIT(taskqueue_thread, &unp_gc_task, 0, unp_gc, NULL);
TASK_INIT(&unp_defer_task, 0, unp_process_defers, NULL);
UNP_LINK_LOCK_INIT();
UNP_DEFERRED_LOCK_INIT();
}
static void
unp_internalize_cleanup_rights(struct mbuf *control)
{
struct cmsghdr *cp;
struct mbuf *m;
void *data;
socklen_t datalen;
for (m = control; m != NULL; m = m->m_next) {
cp = mtod(m, struct cmsghdr *);
if (cp->cmsg_level != SOL_SOCKET ||
cp->cmsg_type != SCM_RIGHTS)
continue;
data = CMSG_DATA(cp);
datalen = (caddr_t)cp + cp->cmsg_len - (caddr_t)data;
unp_freerights(data, datalen / sizeof(struct filedesc *));
}
}
static int
unp_internalize(struct mbuf **controlp, struct thread *td)
{
struct mbuf *control, **initial_controlp;
struct proc *p;
struct filedesc *fdesc;
struct bintime *bt;
struct cmsghdr *cm;
struct cmsgcred *cmcred;
struct filedescent *fde, **fdep, *fdev;
struct file *fp;
struct timeval *tv;
struct timespec *ts;
void *data;
socklen_t clen, datalen;
int i, j, error, *fdp, oldfds;
u_int newlen;
UNP_LINK_UNLOCK_ASSERT();
p = td->td_proc;
fdesc = p->p_fd;
error = 0;
control = *controlp;
clen = control->m_len;
*controlp = NULL;
initial_controlp = controlp;
for (cm = mtod(control, struct cmsghdr *); cm != NULL;) {
if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET
|| cm->cmsg_len > clen || cm->cmsg_len < sizeof(*cm)) {
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);
if (oldfds == 0)
break;
/*
* Check that all the FDs passed in refer to legal
* files. If not, reject the entire operation.
*/
fdp = data;
FILEDESC_SLOCK(fdesc);
for (i = 0; i < oldfds; i++, fdp++) {
fp = fget_locked(fdesc, *fdp);
if (fp == NULL) {
FILEDESC_SUNLOCK(fdesc);
error = EBADF;
goto out;
}
if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) {
FILEDESC_SUNLOCK(fdesc);
error = EOPNOTSUPP;
goto out;
}
}
/*
* Now replace the integer FDs with pointers to the
* file structure and capability rights.
*/
newlen = oldfds * sizeof(fdep[0]);
*controlp = sbcreatecontrol(NULL, newlen,
SCM_RIGHTS, SOL_SOCKET);
if (*controlp == NULL) {
FILEDESC_SUNLOCK(fdesc);
error = E2BIG;
goto out;
}
fdp = data;
for (i = 0; i < oldfds; i++, fdp++) {
if (!fhold(fdesc->fd_ofiles[*fdp].fde_file)) {
fdp = data;
for (j = 0; j < i; j++, fdp++) {
fdrop(fdesc->fd_ofiles[*fdp].
fde_file, td);
}
FILEDESC_SUNLOCK(fdesc);
error = EBADF;
goto out;
}
}
fdp = data;
fdep = (struct filedescent **)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
fdev = malloc(sizeof(*fdev) * oldfds, M_FILECAPS,
M_WAITOK);
for (i = 0; i < oldfds; i++, fdev++, fdp++) {
fde = &fdesc->fd_ofiles[*fdp];
fdep[i] = fdev;
fdep[i]->fde_file = fde->fde_file;
filecaps_copy(&fde->fde_caps,
&fdep[i]->fde_caps, true);
unp_internalize_fp(fdep[i]->fde_file);
}
FILEDESC_SUNLOCK(fdesc);
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;
case SCM_BINTIME:
*controlp = sbcreatecontrol(NULL, sizeof(*bt),
SCM_BINTIME, SOL_SOCKET);
if (*controlp == NULL) {
error = ENOBUFS;
goto out;
}
bt = (struct bintime *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
bintime(bt);
break;
case SCM_REALTIME:
*controlp = sbcreatecontrol(NULL, sizeof(*ts),
SCM_REALTIME, SOL_SOCKET);
if (*controlp == NULL) {
error = ENOBUFS;
goto out;
}
ts = (struct timespec *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
nanotime(ts);
break;
case SCM_MONOTONIC:
*controlp = sbcreatecontrol(NULL, sizeof(*ts),
SCM_MONOTONIC, SOL_SOCKET);
if (*controlp == NULL) {
error = ENOBUFS;
goto out;
}
ts = (struct timespec *)
CMSG_DATA(mtod(*controlp, struct cmsghdr *));
nanouptime(ts);
break;
default:
error = EINVAL;
goto out;
}
if (*controlp != NULL)
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:
if (error != 0 && initial_controlp != NULL)
unp_internalize_cleanup_rights(*initial_controlp);
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);
}
static struct unpcb *
fptounp(struct file *fp)
{
struct socket *so;
if (fp->f_type != DTYPE_SOCKET)
return (NULL);
if ((so = fp->f_data) == NULL)
return (NULL);
if (so->so_proto->pr_domain != &localdomain)
return (NULL);
return sotounpcb(so);
}
static void
unp_discard(struct file *fp)
{
struct unp_defer *dr;
if (unp_externalize_fp(fp)) {
dr = malloc(sizeof(*dr), M_TEMP, M_WAITOK);
dr->ud_fp = fp;
UNP_DEFERRED_LOCK();
SLIST_INSERT_HEAD(&unp_defers, dr, ud_link);
UNP_DEFERRED_UNLOCK();
atomic_add_int(&unp_defers_count, 1);
taskqueue_enqueue(taskqueue_thread, &unp_defer_task);
} else
(void) closef(fp, (struct thread *)NULL);
}
static void
unp_process_defers(void *arg __unused, int pending)
{
struct unp_defer *dr;
SLIST_HEAD(, unp_defer) drl;
int count;
SLIST_INIT(&drl);
for (;;) {
UNP_DEFERRED_LOCK();
if (SLIST_FIRST(&unp_defers) == NULL) {
UNP_DEFERRED_UNLOCK();
break;
}
SLIST_SWAP(&unp_defers, &drl, unp_defer);
UNP_DEFERRED_UNLOCK();
count = 0;
while ((dr = SLIST_FIRST(&drl)) != NULL) {
SLIST_REMOVE_HEAD(&drl, ud_link);
closef(dr->ud_fp, NULL);
free(dr, M_TEMP);
count++;
}
atomic_add_int(&unp_defers_count, -count);
}
}
static void
unp_internalize_fp(struct file *fp)
{
struct unpcb *unp;
UNP_LINK_WLOCK();
if ((unp = fptounp(fp)) != NULL) {
unp->unp_file = fp;
unp->unp_msgcount++;
}
unp_rights++;
UNP_LINK_WUNLOCK();
}
static int
unp_externalize_fp(struct file *fp)
{
struct unpcb *unp;
int ret;
UNP_LINK_WLOCK();
if ((unp = fptounp(fp)) != NULL) {
unp->unp_msgcount--;
ret = 1;
} else
ret = 0;
unp_rights--;
UNP_LINK_WUNLOCK();
return (ret);
}
/*
* 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_marked;
static void
unp_remove_dead_ref(struct filedescent **fdep, int fdcount)
{
struct unpcb *unp;
struct file *fp;
int i;
/*
* This function can only be called from the gc task.
*/
KASSERT(taskqueue_member(taskqueue_thread, curthread) != 0,
("%s: not on gc callout", __func__));
UNP_LINK_LOCK_ASSERT();
for (i = 0; i < fdcount; i++) {
fp = fdep[i]->fde_file;
if ((unp = fptounp(fp)) == NULL)
continue;
if ((unp->unp_gcflag & UNPGC_DEAD) == 0)
continue;
unp->unp_gcrefs--;
}
}
static void
unp_restore_undead_ref(struct filedescent **fdep, int fdcount)
{
struct unpcb *unp;
struct file *fp;
int i;
/*
* This function can only be called from the gc task.
*/
KASSERT(taskqueue_member(taskqueue_thread, curthread) != 0,
("%s: not on gc callout", __func__));
UNP_LINK_LOCK_ASSERT();
for (i = 0; i < fdcount; i++) {
fp = fdep[i]->fde_file;
if ((unp = fptounp(fp)) == NULL)
continue;
if ((unp->unp_gcflag & UNPGC_DEAD) == 0)
continue;
unp->unp_gcrefs++;
unp_marked++;
}
}
static void
unp_gc_scan(struct unpcb *unp, void (*op)(struct filedescent **, int))
{
struct socket *so, *soa;
so = unp->unp_socket;
SOCK_LOCK(so);
if (SOLISTENING(so)) {
/*
* Mark all sockets in our accept queue.
*/
TAILQ_FOREACH(soa, &so->sol_comp, so_list) {
if (sotounpcb(soa)->unp_gcflag & UNPGC_IGNORE_RIGHTS)
continue;
SOCKBUF_LOCK(&soa->so_rcv);
unp_scan(soa->so_rcv.sb_mb, op);
SOCKBUF_UNLOCK(&soa->so_rcv);
}
} else {
/*
* Mark all sockets we reference with RIGHTS.
*/
if ((unp->unp_gcflag & UNPGC_IGNORE_RIGHTS) == 0) {
SOCKBUF_LOCK(&so->so_rcv);
unp_scan(so->so_rcv.sb_mb, op);
SOCKBUF_UNLOCK(&so->so_rcv);
}
}
SOCK_UNLOCK(so);
}
static int unp_recycled;
SYSCTL_INT(_net_local, OID_AUTO, recycled, CTLFLAG_RD, &unp_recycled, 0,
"Number of unreachable sockets claimed by the garbage collector.");
static int unp_taskcount;
SYSCTL_INT(_net_local, OID_AUTO, taskcount, CTLFLAG_RD, &unp_taskcount, 0,
"Number of times the garbage collector has run.");
SYSCTL_UINT(_net_local, OID_AUTO, sockcount, CTLFLAG_RD, &unp_count, 0,
"Number of active local sockets.");
static void
unp_gc(__unused void *arg, int pending)
{
struct unp_head *heads[] = { &unp_dhead, &unp_shead, &unp_sphead,
NULL };
struct unp_head **head;
struct unp_head unp_deadhead; /* List of potentially-dead sockets. */
struct file *f, **unref;
struct unpcb *unp, *unptmp;
int i, total, unp_unreachable;
LIST_INIT(&unp_deadhead);
unp_taskcount++;
UNP_LINK_RLOCK();
/*
* First determine which sockets may be in cycles.
*/
unp_unreachable = 0;
for (head = heads; *head != NULL; head++)
LIST_FOREACH(unp, *head, unp_link) {
KASSERT((unp->unp_gcflag & ~UNPGC_IGNORE_RIGHTS) == 0,
("%s: unp %p has unexpected gc flags 0x%x",
__func__, unp, (unsigned int)unp->unp_gcflag));
f = unp->unp_file;
/*
* Check for an unreachable socket potentially in a
* cycle. It must be in a queue as indicated by
* msgcount, and this must equal the file reference
* count. Note that when msgcount is 0 the file is
* NULL.
*/
if (f != NULL && unp->unp_msgcount != 0 &&
f->f_count == unp->unp_msgcount) {
LIST_INSERT_HEAD(&unp_deadhead, unp, unp_dead);
unp->unp_gcflag |= UNPGC_DEAD;
unp->unp_gcrefs = unp->unp_msgcount;
unp_unreachable++;
}
}
/*
* Scan all sockets previously marked as potentially being in a cycle
* and remove the references each socket holds on any UNPGC_DEAD
* sockets in its queue. After this step, all remaining references on
* sockets marked UNPGC_DEAD should not be part of any cycle.
*/
LIST_FOREACH(unp, &unp_deadhead, unp_dead)
unp_gc_scan(unp, unp_remove_dead_ref);
/*
* If a socket still has a non-negative refcount, it cannot be in a
* cycle. In this case increment refcount of all children iteratively.
* Stop the scan once we do a complete loop without discovering
* a new reachable socket.
*/
do {
unp_marked = 0;
LIST_FOREACH_SAFE(unp, &unp_deadhead, unp_dead, unptmp)
if (unp->unp_gcrefs > 0) {
unp->unp_gcflag &= ~UNPGC_DEAD;
LIST_REMOVE(unp, unp_dead);
KASSERT(unp_unreachable > 0,
("%s: unp_unreachable underflow.",
__func__));
unp_unreachable--;
unp_gc_scan(unp, unp_restore_undead_ref);
}
} while (unp_marked);
UNP_LINK_RUNLOCK();
if (unp_unreachable == 0)
return;
/*
* Allocate space for a local array of dead unpcbs.
* TODO: can this path be simplified by instead using the local
* dead list at unp_deadhead, after taking out references
* on the file object and/or unpcb and dropping the link lock?
*/
unref = malloc(unp_unreachable * sizeof(struct file *),
M_TEMP, M_WAITOK);
/*
* Iterate looking for sockets which have been specifically marked
* as unreachable and store them locally.
*/
UNP_LINK_RLOCK();
total = 0;
LIST_FOREACH(unp, &unp_deadhead, unp_dead) {
KASSERT((unp->unp_gcflag & UNPGC_DEAD) != 0,
("%s: unp %p not marked UNPGC_DEAD", __func__, unp));
unp->unp_gcflag &= ~UNPGC_DEAD;
f = unp->unp_file;
if (unp->unp_msgcount == 0 || f == NULL ||
f->f_count != unp->unp_msgcount ||
!fhold(f))
continue;
unref[total++] = f;
KASSERT(total <= unp_unreachable,
("%s: incorrect unreachable count.", __func__));
}
UNP_LINK_RUNLOCK();
/*
* Now flush all sockets, free'ing rights. This will free the
* struct files associated with these sockets but leave each socket
* with one remaining ref.
*/
for (i = 0; i < total; i++) {
struct socket *so;
so = unref[i]->f_data;
CURVNET_SET(so->so_vnet);
sorflush(so);
CURVNET_RESTORE();
}
/*
* And finally release the sockets so they can be reclaimed.
*/
for (i = 0; i < total; i++)
fdrop(unref[i], NULL);
unp_recycled += total;
free(unref, M_TEMP);
}
static void
unp_dispose_mbuf(struct mbuf *m)
{
if (m)
unp_scan(m, unp_freerights);
}
/*
* Synchronize against unp_gc, which can trip over data as we are freeing it.
*/
static void
unp_dispose(struct socket *so)
{
struct unpcb *unp;
unp = sotounpcb(so);
UNP_LINK_WLOCK();
unp->unp_gcflag |= UNPGC_IGNORE_RIGHTS;
UNP_LINK_WUNLOCK();
if (!SOLISTENING(so))
unp_dispose_mbuf(so->so_rcv.sb_mb);
}
static void
unp_scan(struct mbuf *m0, void (*op)(struct filedescent **, int))
{
struct mbuf *m;
struct cmsghdr *cm;
void *data;
socklen_t clen, datalen;
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) {
(*op)(data, datalen /
sizeof(struct filedescent *));
}
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_nextpkt;
}
}
/*
* A helper function called by VFS before socket-type vnode reclamation.
* For an active vnode it clears unp_vnode pointer and decrements unp_vnode
* use count.
*/
void
vfs_unp_reclaim(struct vnode *vp)
{
struct unpcb *unp;
int active;
struct mtx *vplock;
ASSERT_VOP_ELOCKED(vp, "vfs_unp_reclaim");
KASSERT(vp->v_type == VSOCK,
("vfs_unp_reclaim: vp->v_type != VSOCK"));
active = 0;
vplock = mtx_pool_find(mtxpool_sleep, vp);
mtx_lock(vplock);
VOP_UNP_CONNECT(vp, &unp);
if (unp == NULL)
goto done;
UNP_PCB_LOCK(unp);
if (unp->unp_vnode == vp) {
VOP_UNP_DETACH(vp);
unp->unp_vnode = NULL;
active = 1;
}
UNP_PCB_UNLOCK(unp);
done:
mtx_unlock(vplock);
if (active)
vunref(vp);
}
#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_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_pid: %d cr_ngroups: %d\n",
xu->cr_version, xu->cr_uid, xu->cr_pid, 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: %ju unp_conn: %p\n", (uintmax_t)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_gencnt: %llu\n",
(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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