4f1f0ef523
used to mark UNIX domain sockets as being in the process of binding or connecting. Use these to prevent simultaneous bind or connect operations by multiple threads or processes on the same socket at the same time, which closes race conditions present in the UNIX domain socket implementation since inception.
140 lines
5.3 KiB
C
140 lines
5.3 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)unpcb.h 8.1 (Berkeley) 6/2/93
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* $FreeBSD$
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*/
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#ifndef _SYS_UNPCB_H_
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#define _SYS_UNPCB_H_
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#include <sys/queue.h>
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#include <sys/ucred.h>
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/*
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* Protocol control block for an active
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* instance of a UNIX internal protocol.
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*
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* A socket may be associated with a vnode in the
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* filesystem. If so, the unp_vnode pointer holds
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* a reference count to this vnode, which should be irele'd
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* when the socket goes away.
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*
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* A socket may be connected to another socket, in which
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* case the control block of the socket to which it is connected
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* is given by unp_conn.
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*
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* A socket may be referenced by a number of sockets (e.g. several
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* sockets may be connected to a datagram socket.) These sockets
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* are in a linked list starting with unp_refs, linked through
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* unp_nextref and null-terminated. Note that a socket may be referenced
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* by a number of other sockets and may also reference a socket (not
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* necessarily one which is referencing it). This generates
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* the need for unp_refs and unp_nextref to be separate fields.
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*
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* Stream sockets keep copies of receive sockbuf sb_cc and sb_mbcnt
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* so that changes in the sockbuf may be computed to modify
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* back pressure on the sender accordingly.
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*/
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typedef u_quad_t unp_gen_t;
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LIST_HEAD(unp_head, unpcb);
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struct unpcb {
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LIST_ENTRY(unpcb) unp_link; /* glue on list of all PCBs */
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struct socket *unp_socket; /* pointer back to socket */
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struct vnode *unp_vnode; /* if associated with file */
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ino_t unp_ino; /* fake inode number */
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struct unpcb *unp_conn; /* control block of connected socket */
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struct unp_head unp_refs; /* referencing socket linked list */
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LIST_ENTRY(unpcb) unp_reflink; /* link in unp_refs list */
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struct sockaddr_un *unp_addr; /* bound address of socket */
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int unp_cc; /* copy of rcv.sb_cc */
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int unp_mbcnt; /* copy of rcv.sb_mbcnt */
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unp_gen_t unp_gencnt; /* generation count of this instance */
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int unp_flags; /* flags */
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struct xucred unp_peercred; /* peer credentials, if applicable */
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};
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/*
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* Flags in unp_flags.
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*
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* UNP_HAVEPC - indicates that the unp_peercred member is filled in
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* and is really the credentials of the connected peer. This is used
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* to determine whether the contents should be sent to the user or
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* not.
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*
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* UNP_HAVEPCCACHED - indicates that the unp_peercred member is filled
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* in, but does *not* contain the credentials of the connected peer
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* (there may not even be a peer). This is set in unp_listen() when
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* it fills in unp_peercred for later consumption by unp_connect().
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*/
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#define UNP_HAVEPC 0x001
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#define UNP_HAVEPCCACHED 0x002
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#define UNP_WANTCRED 0x004 /* credentials wanted */
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#define UNP_CONNWAIT 0x008 /* connect blocks until accepted */
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/*
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* These flags are used to handle non-atomicity in connect() and bind()
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* operations on a socket: in particular, to avoid races between multiple
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* threads or processes operating simultaneously on the same socket.
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*/
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#define UNP_CONNECTING 0x010 /* Currently connecting. */
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#define UNP_BINDING 0x020 /* Currently binding. */
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#define sotounpcb(so) ((struct unpcb *)((so)->so_pcb))
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/* Hack alert -- this structure depends on <sys/socketvar.h>. */
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#ifdef _SYS_SOCKETVAR_H_
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struct xunpcb {
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size_t xu_len; /* length of this structure */
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struct unpcb *xu_unpp; /* to help netstat, fstat */
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struct unpcb xu_unp; /* our information */
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union {
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struct sockaddr_un xuu_addr; /* our bound address */
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char xu_dummy1[256];
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} xu_au;
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#define xu_addr xu_au.xuu_addr
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union {
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struct sockaddr_un xuu_caddr; /* their bound address */
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char xu_dummy2[256];
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} xu_cau;
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#define xu_caddr xu_cau.xuu_caddr
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struct xsocket xu_socket;
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u_quad_t xu_alignment_hack;
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};
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struct xunpgen {
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size_t xug_len;
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u_int xug_count;
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unp_gen_t xug_gen;
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so_gen_t xug_sogen;
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};
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#endif /* _SYS_SOCKETVAR_H_ */
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#endif /* _SYS_UNPCB_H_ */
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