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freebsd/sys/kern/sys_socket.c
Robert Watson d43c1f67cc Annotate two intentionally unlocked reads with comments.
Annotate a potentially inconsistent result returned to user space when
performing fstaT() on a socket due to not using socket buffer locking.
2004-06-20 17:35:50 +00:00

273 lines
6.8 KiB
C

/*
* Copyright (c) 1982, 1986, 1990, 1993
* The Regents of the University of California. 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.
*
* @(#)sys_socket.c 8.1 (Berkeley) 6/10/93
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/mac.h>
#include <sys/protosw.h>
#include <sys/sigio.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/filio.h> /* XXX */
#include <sys/sockio.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <sys/ucred.h>
#include <net/if.h>
#include <net/route.h>
struct fileops socketops = {
.fo_read = soo_read,
.fo_write = soo_write,
.fo_ioctl = soo_ioctl,
.fo_poll = soo_poll,
.fo_kqfilter = soo_kqfilter,
.fo_stat = soo_stat,
.fo_close = soo_close,
.fo_flags = DFLAG_PASSABLE
};
/* ARGSUSED */
int
soo_read(fp, uio, active_cred, flags, td)
struct file *fp;
struct uio *uio;
struct ucred *active_cred;
struct thread *td;
int flags;
{
struct socket *so = fp->f_data;
int error;
NET_LOCK_GIANT();
#ifdef MAC
SOCK_LOCK(so);
error = mac_check_socket_receive(active_cred, so);
SOCK_UNLOCK(so);
if (error) {
NET_UNLOCK_GIANT();
return (error);
}
#endif
error = so->so_proto->pr_usrreqs->pru_soreceive(so, 0, uio, 0, 0, 0);
NET_UNLOCK_GIANT();
return (error);
}
/* ARGSUSED */
int
soo_write(fp, uio, active_cred, flags, td)
struct file *fp;
struct uio *uio;
struct ucred *active_cred;
struct thread *td;
int flags;
{
struct socket *so = fp->f_data;
int error;
NET_LOCK_GIANT();
#ifdef MAC
SOCK_LOCK(so);
error = mac_check_socket_send(active_cred, so);
SOCK_UNLOCK(so);
if (error) {
NET_UNLOCK_GIANT();
return (error);
}
#endif
error = so->so_proto->pr_usrreqs->pru_sosend(so, 0, uio, 0, 0, 0,
uio->uio_td);
NET_UNLOCK_GIANT();
return (error);
}
int
soo_ioctl(fp, cmd, data, active_cred, td)
struct file *fp;
u_long cmd;
void *data;
struct ucred *active_cred;
struct thread *td;
{
register struct socket *so = fp->f_data;
switch (cmd) {
case FIONBIO:
SOCK_LOCK(so);
if (*(int *)data)
so->so_state |= SS_NBIO;
else
so->so_state &= ~SS_NBIO;
SOCK_UNLOCK(so);
return (0);
case FIOASYNC:
/*
* XXXRW: This code separately acquires SOCK_LOCK(so)
* and SOCKBUF_LOCK(&so->so_rcv) even though they are
* the same mutex to avoid introducing the assumption
* that they are the same.
*/
if (*(int *)data) {
SOCK_LOCK(so);
so->so_state |= SS_ASYNC;
SOCK_UNLOCK(so);
SOCKBUF_LOCK(&so->so_rcv);
so->so_rcv.sb_flags |= SB_ASYNC;
SOCKBUF_UNLOCK(&so->so_rcv);
SOCKBUF_LOCK(&so->so_snd);
so->so_snd.sb_flags |= SB_ASYNC;
SOCKBUF_UNLOCK(&so->so_snd);
} else {
SOCK_LOCK(so);
so->so_state &= ~SS_ASYNC;
SOCK_UNLOCK(so);
SOCKBUF_LOCK(&so->so_rcv);
so->so_rcv.sb_flags &= ~SB_ASYNC;
SOCKBUF_UNLOCK(&so->so_rcv);
SOCKBUF_LOCK(&so->so_snd);
so->so_snd.sb_flags &= ~SB_ASYNC;
SOCKBUF_UNLOCK(&so->so_snd);
}
return (0);
case FIONREAD:
/* Unlocked read. */
*(int *)data = so->so_rcv.sb_cc;
return (0);
case FIOSETOWN:
return (fsetown(*(int *)data, &so->so_sigio));
case FIOGETOWN:
*(int *)data = fgetown(&so->so_sigio);
return (0);
case SIOCSPGRP:
return (fsetown(-(*(int *)data), &so->so_sigio));
case SIOCGPGRP:
*(int *)data = -fgetown(&so->so_sigio);
return (0);
case SIOCATMARK:
/* Unlocked read. */
*(int *)data = (so->so_rcv.sb_state & SBS_RCVATMARK) != 0;
return (0);
}
/*
* Interface/routing/protocol specific ioctls:
* interface and routing ioctls should have a
* different entry since a socket's unnecessary
*/
if (IOCGROUP(cmd) == 'i')
return (ifioctl(so, cmd, data, td));
if (IOCGROUP(cmd) == 'r')
return (rtioctl(cmd, data));
return ((*so->so_proto->pr_usrreqs->pru_control)(so, cmd, data, 0, td));
}
int
soo_poll(fp, events, active_cred, td)
struct file *fp;
int events;
struct ucred *active_cred;
struct thread *td;
{
struct socket *so = fp->f_data;
return so->so_proto->pr_usrreqs->pru_sopoll(so, events,
fp->f_cred, td);
}
int
soo_stat(fp, ub, active_cred, td)
struct file *fp;
struct stat *ub;
struct ucred *active_cred;
struct thread *td;
{
struct socket *so = fp->f_data;
bzero((caddr_t)ub, sizeof (*ub));
ub->st_mode = S_IFSOCK;
/*
* If SBS_CANTRCVMORE is set, but there's still data left in the
* receive buffer, the socket is still readable.
*
* XXXRW: perhaps should lock socket buffer so st_size result
* is consistent.
*/
/* Unlocked read. */
if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) == 0 ||
so->so_rcv.sb_cc != 0)
ub->st_mode |= S_IRUSR | S_IRGRP | S_IROTH;
if ((so->so_snd.sb_state & SBS_CANTSENDMORE) == 0)
ub->st_mode |= S_IWUSR | S_IWGRP | S_IWOTH;
ub->st_size = so->so_rcv.sb_cc - so->so_rcv.sb_ctl;
ub->st_uid = so->so_cred->cr_uid;
ub->st_gid = so->so_cred->cr_gid;
return ((*so->so_proto->pr_usrreqs->pru_sense)(so, ub));
}
/*
* API socket close on file pointer. We call soclose() to close the
* socket (including initiating closing protocols). soclose() will
* sorele() the file reference but the actual socket will not go away
* until the socket's ref count hits 0.
*/
/* ARGSUSED */
int
soo_close(fp, td)
struct file *fp;
struct thread *td;
{
int error = 0;
struct socket *so;
so = fp->f_data;
fp->f_ops = &badfileops;
fp->f_data = NULL;
if (so)
error = soclose(so);
return (error);
}