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freebsd-dev/sys/kern/sys_generic.c
Ruslan Ermilov a1b0a18096 Prevent IOC_IN with zero size argument (this is only supported 
if backward copatibility options are present) from attempting
to free memory that wasn't allocated.  This is an old bug, and
previously it would attempt to free a null pointer.  I noticed
this bug when working on the previous revision, but forgot to
fix it.

Security:	local DoS
Reported by:	Peter Holm
MFC after:	3 days
2006-10-14 19:01:55 +00:00

1183 lines
24 KiB
C
Raw Blame History

/*-
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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_generic.c 8.5 (Berkeley) 1/21/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include "opt_ktrace.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/filedesc.h>
#include <sys/filio.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/socketvar.h>
#include <sys/uio.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/malloc.h>
#include <sys/poll.h>
#include <sys/resourcevar.h>
#include <sys/selinfo.h>
#include <sys/sleepqueue.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/vnode.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/condvar.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#include <vm/vm.h>
#include <vm/vm_page.h>
static MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer");
static MALLOC_DEFINE(M_SELECT, "select", "select() buffer");
MALLOC_DEFINE(M_IOV, "iov", "large iov's");
static int pollscan(struct thread *, struct pollfd *, u_int);
static int selscan(struct thread *, fd_mask **, fd_mask **, int);
static int dofileread(struct thread *, int, struct file *, struct uio *,
off_t, int);
static int dofilewrite(struct thread *, int, struct file *, struct uio *,
off_t, int);
static void doselwakeup(struct selinfo *, int);
/*
* Read system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct read_args {
int fd;
void *buf;
size_t nbyte;
};
#endif
/*
* MPSAFE
*/
int
read(td, uap)
struct thread *td;
struct read_args *uap;
{
struct uio auio;
struct iovec aiov;
int error;
if (uap->nbyte > INT_MAX)
return (EINVAL);
aiov.iov_base = uap->buf;
aiov.iov_len = uap->nbyte;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_resid = uap->nbyte;
auio.uio_segflg = UIO_USERSPACE;
error = kern_readv(td, uap->fd, &auio);
return(error);
}
/*
* Positioned read system call
*/
#ifndef _SYS_SYSPROTO_H_
struct pread_args {
int fd;
void *buf;
size_t nbyte;
int pad;
off_t offset;
};
#endif
/*
* MPSAFE
*/
int
pread(td, uap)
struct thread *td;
struct pread_args *uap;
{
struct uio auio;
struct iovec aiov;
int error;
if (uap->nbyte > INT_MAX)
return (EINVAL);
aiov.iov_base = uap->buf;
aiov.iov_len = uap->nbyte;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_resid = uap->nbyte;
auio.uio_segflg = UIO_USERSPACE;
error = kern_preadv(td, uap->fd, &auio, uap->offset);
return(error);
}
/*
* Scatter read system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct readv_args {
int fd;
struct iovec *iovp;
u_int iovcnt;
};
#endif
/*
* MPSAFE
*/
int
readv(struct thread *td, struct readv_args *uap)
{
struct uio *auio;
int error;
error = copyinuio(uap->iovp, uap->iovcnt, &auio);
if (error)
return (error);
error = kern_readv(td, uap->fd, auio);
free(auio, M_IOV);
return (error);
}
int
kern_readv(struct thread *td, int fd, struct uio *auio)
{
struct file *fp;
int error;
error = fget_read(td, fd, &fp);
if (error)
return (error);
error = dofileread(td, fd, fp, auio, (off_t)-1, 0);
fdrop(fp, td);
return (error);
}
/*
* Scatter positioned read system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct preadv_args {
int fd;
struct iovec *iovp;
u_int iovcnt;
off_t offset;
};
#endif
/*
* MPSAFE
*/
int
preadv(struct thread *td, struct preadv_args *uap)
{
struct uio *auio;
int error;
error = copyinuio(uap->iovp, uap->iovcnt, &auio);
if (error)
return (error);
error = kern_preadv(td, uap->fd, auio, uap->offset);
free(auio, M_IOV);
return (error);
}
int
kern_preadv(td, fd, auio, offset)
struct thread *td;
int fd;
struct uio *auio;
off_t offset;
{
struct file *fp;
int error;
error = fget_read(td, fd, &fp);
if (error)
return (error);
if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
error = ESPIPE;
else if (offset < 0 && fp->f_vnode->v_type != VCHR)
error = EINVAL;
else
error = dofileread(td, fd, fp, auio, offset, FOF_OFFSET);
fdrop(fp, td);
return (error);
}
/*
* Common code for readv and preadv that reads data in
* from a file using the passed in uio, offset, and flags.
*/
static int
dofileread(td, fd, fp, auio, offset, flags)
struct thread *td;
int fd;
struct file *fp;
struct uio *auio;
off_t offset;
int flags;
{
ssize_t cnt;
int error;
#ifdef KTRACE
struct uio *ktruio = NULL;
#endif
/* Finish zero length reads right here */
if (auio->uio_resid == 0) {
td->td_retval[0] = 0;
return(0);
}
auio->uio_rw = UIO_READ;
auio->uio_offset = offset;
auio->uio_td = td;
#ifdef KTRACE
if (KTRPOINT(td, KTR_GENIO))
ktruio = cloneuio(auio);
#endif
cnt = auio->uio_resid;
if ((error = fo_read(fp, auio, td->td_ucred, flags, td))) {
if (auio->uio_resid != cnt && (error == ERESTART ||
error == EINTR || error == EWOULDBLOCK))
error = 0;
}
cnt -= auio->uio_resid;
#ifdef KTRACE
if (ktruio != NULL) {
ktruio->uio_resid = cnt;
ktrgenio(fd, UIO_READ, ktruio, error);
}
#endif
td->td_retval[0] = cnt;
return (error);
}
/*
* Write system call
*/
#ifndef _SYS_SYSPROTO_H_
struct write_args {
int fd;
const void *buf;
size_t nbyte;
};
#endif
/*
* MPSAFE
*/
int
write(td, uap)
struct thread *td;
struct write_args *uap;
{
struct uio auio;
struct iovec aiov;
int error;
if (uap->nbyte > INT_MAX)
return (EINVAL);
aiov.iov_base = (void *)(uintptr_t)uap->buf;
aiov.iov_len = uap->nbyte;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_resid = uap->nbyte;
auio.uio_segflg = UIO_USERSPACE;
error = kern_writev(td, uap->fd, &auio);
return(error);
}
/*
* Positioned write system call
*/
#ifndef _SYS_SYSPROTO_H_
struct pwrite_args {
int fd;
const void *buf;
size_t nbyte;
int pad;
off_t offset;
};
#endif
/*
* MPSAFE
*/
int
pwrite(td, uap)
struct thread *td;
struct pwrite_args *uap;
{
struct uio auio;
struct iovec aiov;
int error;
if (uap->nbyte > INT_MAX)
return (EINVAL);
aiov.iov_base = (void *)(uintptr_t)uap->buf;
aiov.iov_len = uap->nbyte;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_resid = uap->nbyte;
auio.uio_segflg = UIO_USERSPACE;
error = kern_pwritev(td, uap->fd, &auio, uap->offset);
return(error);
}
/*
* Gather write system call
*/
#ifndef _SYS_SYSPROTO_H_
struct writev_args {
int fd;
struct iovec *iovp;
u_int iovcnt;
};
#endif
/*
* MPSAFE
*/
int
writev(struct thread *td, struct writev_args *uap)
{
struct uio *auio;
int error;
error = copyinuio(uap->iovp, uap->iovcnt, &auio);
if (error)
return (error);
error = kern_writev(td, uap->fd, auio);
free(auio, M_IOV);
return (error);
}
int
kern_writev(struct thread *td, int fd, struct uio *auio)
{
struct file *fp;
int error;
error = fget_write(td, fd, &fp);
if (error)
return (error);
error = dofilewrite(td, fd, fp, auio, (off_t)-1, 0);
fdrop(fp, td);
return (error);
}
/*
* Gather positioned write system call
*/
#ifndef _SYS_SYSPROTO_H_
struct pwritev_args {
int fd;
struct iovec *iovp;
u_int iovcnt;
off_t offset;
};
#endif
/*
* MPSAFE
*/
int
pwritev(struct thread *td, struct pwritev_args *uap)
{
struct uio *auio;
int error;
error = copyinuio(uap->iovp, uap->iovcnt, &auio);
if (error)
return (error);
error = kern_pwritev(td, uap->fd, auio, uap->offset);
free(auio, M_IOV);
return (error);
}
int
kern_pwritev(td, fd, auio, offset)
struct thread *td;
struct uio *auio;
int fd;
off_t offset;
{
struct file *fp;
int error;
error = fget_write(td, fd, &fp);
if (error)
return (error);
if (!(fp->f_ops->fo_flags & DFLAG_SEEKABLE))
error = ESPIPE;
else if (offset < 0 && fp->f_vnode->v_type != VCHR)
error = EINVAL;
else
error = dofilewrite(td, fd, fp, auio, offset, FOF_OFFSET);
fdrop(fp, td);
return (error);
}
/*
* Common code for writev and pwritev that writes data to
* a file using the passed in uio, offset, and flags.
*/
static int
dofilewrite(td, fd, fp, auio, offset, flags)
struct thread *td;
int fd;
struct file *fp;
struct uio *auio;
off_t offset;
int flags;
{
ssize_t cnt;
int error;
#ifdef KTRACE
struct uio *ktruio = NULL;
#endif
auio->uio_rw = UIO_WRITE;
auio->uio_td = td;
auio->uio_offset = offset;
#ifdef KTRACE
if (KTRPOINT(td, KTR_GENIO))
ktruio = cloneuio(auio);
#endif
cnt = auio->uio_resid;
if (fp->f_type == DTYPE_VNODE)
bwillwrite();
if ((error = fo_write(fp, auio, td->td_ucred, flags, td))) {
if (auio->uio_resid != cnt && (error == ERESTART ||
error == EINTR || error == EWOULDBLOCK))
error = 0;
/* Socket layer is responsible for issuing SIGPIPE. */
if (error == EPIPE) {
PROC_LOCK(td->td_proc);
psignal(td->td_proc, SIGPIPE);
PROC_UNLOCK(td->td_proc);
}
}
cnt -= auio->uio_resid;
#ifdef KTRACE
if (ktruio != NULL) {
ktruio->uio_resid = cnt;
ktrgenio(fd, UIO_WRITE, ktruio, error);
}
#endif
td->td_retval[0] = cnt;
return (error);
}
/*
* Ioctl system call
*/
#ifndef _SYS_SYSPROTO_H_
struct ioctl_args {
int fd;
u_long com;
caddr_t data;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
ioctl(struct thread *td, struct ioctl_args *uap)
{
u_long com;
int arg, error;
u_int size;
caddr_t data;
if (uap->com > 0xffffffff) {
printf(
"WARNING pid %d (%s): ioctl sign-extension ioctl %lx\n",
td->td_proc->p_pid, td->td_proc->p_comm, uap->com);
uap->com &= 0xffffffff;
}
com = uap->com;
/*
* Interpret high order word to find amount of data to be
* copied to/from the user's address space.
*/
size = IOCPARM_LEN(com);
if ((size > IOCPARM_MAX) ||
((com & (IOC_VOID | IOC_IN | IOC_OUT)) == 0) ||
#if defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) || defined(COMPAT_43)
((com & IOC_OUT) && size == 0) ||
#else
((com & (IOC_IN | IOC_OUT)) && size == 0) ||
#endif
((com & IOC_VOID) && size > 0 && size != sizeof(int)))
return (ENOTTY);
if (size > 0) {
if (!(com & IOC_VOID))
data = malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
else {
/* Integer argument. */
arg = (intptr_t)uap->data;
data = (void *)&arg;
size = 0;
}
} else
data = (void *)&uap->data;
if (com & IOC_IN) {
error = copyin(uap->data, data, (u_int)size);
if (error) {
if (size > 0)
free(data, M_IOCTLOPS);
return (error);
}
} else if (com & IOC_OUT) {
/*
* Zero the buffer so the user always
* gets back something deterministic.
*/
bzero(data, size);
}
error = kern_ioctl(td, uap->fd, com, data);
if (error == 0 && (com & IOC_OUT))
error = copyout(data, uap->data, (u_int)size);
if (size > 0)
free(data, M_IOCTLOPS);
return (error);
}
int
kern_ioctl(struct thread *td, int fd, u_long com, caddr_t data)
{
struct file *fp;
struct filedesc *fdp;
int error;
int tmp;
if ((error = fget(td, fd, &fp)) != 0)
return (error);
if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
fdrop(fp, td);
return (EBADF);
}
fdp = td->td_proc->p_fd;
switch (com) {
case FIONCLEX:
FILEDESC_LOCK_FAST(fdp);
fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE;
FILEDESC_UNLOCK_FAST(fdp);
goto out;
case FIOCLEX:
FILEDESC_LOCK_FAST(fdp);
fdp->fd_ofileflags[fd] |= UF_EXCLOSE;
FILEDESC_UNLOCK_FAST(fdp);
goto out;
case FIONBIO:
FILE_LOCK(fp);
if ((tmp = *(int *)data))
fp->f_flag |= FNONBLOCK;
else
fp->f_flag &= ~FNONBLOCK;
FILE_UNLOCK(fp);
data = (void *)&tmp;
break;
case FIOASYNC:
FILE_LOCK(fp);
if ((tmp = *(int *)data))
fp->f_flag |= FASYNC;
else
fp->f_flag &= ~FASYNC;
FILE_UNLOCK(fp);
data = (void *)&tmp;
break;
}
error = fo_ioctl(fp, com, data, td->td_ucred, td);
out:
fdrop(fp, td);
return (error);
}
/*
* sellock and selwait are initialized in selectinit() via SYSINIT.
*/
struct mtx sellock;
struct cv selwait;
u_int nselcoll; /* Select collisions since boot */
SYSCTL_UINT(_kern, OID_AUTO, nselcoll, CTLFLAG_RD, &nselcoll, 0, "");
/*
* Select system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct select_args {
int nd;
fd_set *in, *ou, *ex;
struct timeval *tv;
};
#endif
/*
* MPSAFE
*/
int
select(td, uap)
register struct thread *td;
register struct select_args *uap;
{
struct timeval tv, *tvp;
int error;
if (uap->tv != NULL) {
error = copyin(uap->tv, &tv, sizeof(tv));
if (error)
return (error);
tvp = &tv;
} else
tvp = NULL;
return (kern_select(td, uap->nd, uap->in, uap->ou, uap->ex, tvp));
}
int
kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
fd_set *fd_ex, struct timeval *tvp)
{
struct filedesc *fdp;
/*
* The magic 2048 here is chosen to be just enough for FD_SETSIZE
* infds with the new FD_SETSIZE of 1024, and more than enough for
* FD_SETSIZE infds, outfds and exceptfds with the old FD_SETSIZE
* of 256.
*/
fd_mask s_selbits[howmany(2048, NFDBITS)];
fd_mask *ibits[3], *obits[3], *selbits, *sbp;
struct timeval atv, rtv, ttv;
int error, timo;
u_int ncoll, nbufbytes, ncpbytes, nfdbits;
if (nd < 0)
return (EINVAL);
fdp = td->td_proc->p_fd;
FILEDESC_LOCK_FAST(fdp);
if (nd > td->td_proc->p_fd->fd_nfiles)
nd = td->td_proc->p_fd->fd_nfiles; /* forgiving; slightly wrong */
FILEDESC_UNLOCK_FAST(fdp);
/*
* Allocate just enough bits for the non-null fd_sets. Use the
* preallocated auto buffer if possible.
*/
nfdbits = roundup(nd, NFDBITS);
ncpbytes = nfdbits / NBBY;
nbufbytes = 0;
if (fd_in != NULL)
nbufbytes += 2 * ncpbytes;
if (fd_ou != NULL)
nbufbytes += 2 * ncpbytes;
if (fd_ex != NULL)
nbufbytes += 2 * ncpbytes;
if (nbufbytes <= sizeof s_selbits)
selbits = &s_selbits[0];
else
selbits = malloc(nbufbytes, M_SELECT, M_WAITOK);
/*
* Assign pointers into the bit buffers and fetch the input bits.
* Put the output buffers together so that they can be bzeroed
* together.
*/
sbp = selbits;
#define getbits(name, x) \
do { \
if (name == NULL) \
ibits[x] = NULL; \
else { \
ibits[x] = sbp + nbufbytes / 2 / sizeof *sbp; \
obits[x] = sbp; \
sbp += ncpbytes / sizeof *sbp; \
error = copyin(name, ibits[x], ncpbytes); \
if (error != 0) \
goto done_nosellock; \
} \
} while (0)
getbits(fd_in, 0);
getbits(fd_ou, 1);
getbits(fd_ex, 2);
#undef getbits
if (nbufbytes != 0)
bzero(selbits, nbufbytes / 2);
if (tvp != NULL) {
atv = *tvp;
if (itimerfix(&atv)) {
error = EINVAL;
goto done_nosellock;
}
getmicrouptime(&rtv);
timevaladd(&atv, &rtv);
} else {
atv.tv_sec = 0;
atv.tv_usec = 0;
}
timo = 0;
TAILQ_INIT(&td->td_selq);
mtx_lock(&sellock);
retry:
ncoll = nselcoll;
mtx_lock_spin(&sched_lock);
td->td_flags |= TDF_SELECT;
mtx_unlock_spin(&sched_lock);
mtx_unlock(&sellock);
error = selscan(td, ibits, obits, nd);
mtx_lock(&sellock);
if (error || td->td_retval[0])
goto done;
if (atv.tv_sec || atv.tv_usec) {
getmicrouptime(&rtv);
if (timevalcmp(&rtv, &atv, >=))
goto done;
ttv = atv;
timevalsub(&ttv, &rtv);
timo = ttv.tv_sec > 24 * 60 * 60 ?
24 * 60 * 60 * hz : tvtohz(&ttv);
}
/*
* An event of interest may occur while we do not hold
* sellock, so check TDF_SELECT and the number of
* collisions and rescan the file descriptors if
* necessary.
*/
mtx_lock_spin(&sched_lock);
if ((td->td_flags & TDF_SELECT) == 0 || nselcoll != ncoll) {
mtx_unlock_spin(&sched_lock);
goto retry;
}
mtx_unlock_spin(&sched_lock);
if (timo > 0)
error = cv_timedwait_sig(&selwait, &sellock, timo);
else
error = cv_wait_sig(&selwait, &sellock);
if (error == 0)
goto retry;
done:
clear_selinfo_list(td);
mtx_lock_spin(&sched_lock);
td->td_flags &= ~TDF_SELECT;
mtx_unlock_spin(&sched_lock);
mtx_unlock(&sellock);
done_nosellock:
/* select is not restarted after signals... */
if (error == ERESTART)
error = EINTR;
if (error == EWOULDBLOCK)
error = 0;
#define putbits(name, x) \
if (name && (error2 = copyout(obits[x], name, ncpbytes))) \
error = error2;
if (error == 0) {
int error2;
putbits(fd_in, 0);
putbits(fd_ou, 1);
putbits(fd_ex, 2);
#undef putbits
}
if (selbits != &s_selbits[0])
free(selbits, M_SELECT);
return (error);
}
static int
selscan(td, ibits, obits, nfd)
struct thread *td;
fd_mask **ibits, **obits;
int nfd;
{
int msk, i, fd;
fd_mask bits;
struct file *fp;
int n = 0;
/* Note: backend also returns POLLHUP/POLLERR if appropriate. */
static int flag[3] = { POLLRDNORM, POLLWRNORM, POLLRDBAND };
struct filedesc *fdp = td->td_proc->p_fd;
FILEDESC_LOCK(fdp);
for (msk = 0; msk < 3; msk++) {
if (ibits[msk] == NULL)
continue;
for (i = 0; i < nfd; i += NFDBITS) {
bits = ibits[msk][i/NFDBITS];
/* ffs(int mask) not portable, fd_mask is long */
for (fd = i; bits && fd < nfd; fd++, bits >>= 1) {
if (!(bits & 1))
continue;
if ((fp = fget_locked(fdp, fd)) == NULL) {
FILEDESC_UNLOCK(fdp);
return (EBADF);
}
if (fo_poll(fp, flag[msk], td->td_ucred,
td)) {
obits[msk][(fd)/NFDBITS] |=
((fd_mask)1 << ((fd) % NFDBITS));
n++;
}
}
}
}
FILEDESC_UNLOCK(fdp);
td->td_retval[0] = n;
return (0);
}
/*
* Poll system call.
*/
#ifndef _SYS_SYSPROTO_H_
struct poll_args {
struct pollfd *fds;
u_int nfds;
int timeout;
};
#endif
/*
* MPSAFE
*/
int
poll(td, uap)
struct thread *td;
struct poll_args *uap;
{
struct pollfd *bits;
struct pollfd smallbits[32];
struct timeval atv, rtv, ttv;
int error = 0, timo;
u_int ncoll, nfds;
size_t ni;
nfds = uap->nfds;
/*
* This is kinda bogus. We have fd limits, but that is not
* really related to the size of the pollfd array. Make sure
* we let the process use at least FD_SETSIZE entries and at
* least enough for the current limits. We want to be reasonably
* safe, but not overly restrictive.
*/
PROC_LOCK(td->td_proc);
if ((nfds > lim_cur(td->td_proc, RLIMIT_NOFILE)) &&
(nfds > FD_SETSIZE)) {
PROC_UNLOCK(td->td_proc);
error = EINVAL;
goto done2;
}
PROC_UNLOCK(td->td_proc);
ni = nfds * sizeof(struct pollfd);
if (ni > sizeof(smallbits))
bits = malloc(ni, M_TEMP, M_WAITOK);
else
bits = smallbits;
error = copyin(uap->fds, bits, ni);
if (error)
goto done_nosellock;
if (uap->timeout != INFTIM) {
atv.tv_sec = uap->timeout / 1000;
atv.tv_usec = (uap->timeout % 1000) * 1000;
if (itimerfix(&atv)) {
error = EINVAL;
goto done_nosellock;
}
getmicrouptime(&rtv);
timevaladd(&atv, &rtv);
} else {
atv.tv_sec = 0;
atv.tv_usec = 0;
}
timo = 0;
TAILQ_INIT(&td->td_selq);
mtx_lock(&sellock);
retry:
ncoll = nselcoll;
mtx_lock_spin(&sched_lock);
td->td_flags |= TDF_SELECT;
mtx_unlock_spin(&sched_lock);
mtx_unlock(&sellock);
error = pollscan(td, bits, nfds);
mtx_lock(&sellock);
if (error || td->td_retval[0])
goto done;
if (atv.tv_sec || atv.tv_usec) {
getmicrouptime(&rtv);
if (timevalcmp(&rtv, &atv, >=))
goto done;
ttv = atv;
timevalsub(&ttv, &rtv);
timo = ttv.tv_sec > 24 * 60 * 60 ?
24 * 60 * 60 * hz : tvtohz(&ttv);
}
/*
* An event of interest may occur while we do not hold
* sellock, so check TDF_SELECT and the number of collisions
* and rescan the file descriptors if necessary.
*/
mtx_lock_spin(&sched_lock);
if ((td->td_flags & TDF_SELECT) == 0 || nselcoll != ncoll) {
mtx_unlock_spin(&sched_lock);
goto retry;
}
mtx_unlock_spin(&sched_lock);
if (timo > 0)
error = cv_timedwait_sig(&selwait, &sellock, timo);
else
error = cv_wait_sig(&selwait, &sellock);
if (error == 0)
goto retry;
done:
clear_selinfo_list(td);
mtx_lock_spin(&sched_lock);
td->td_flags &= ~TDF_SELECT;
mtx_unlock_spin(&sched_lock);
mtx_unlock(&sellock);
done_nosellock:
/* poll is not restarted after signals... */
if (error == ERESTART)
error = EINTR;
if (error == EWOULDBLOCK)
error = 0;
if (error == 0) {
error = copyout(bits, uap->fds, ni);
if (error)
goto out;
}
out:
if (ni > sizeof(smallbits))
free(bits, M_TEMP);
done2:
return (error);
}
static int
pollscan(td, fds, nfd)
struct thread *td;
struct pollfd *fds;
u_int nfd;
{
register struct filedesc *fdp = td->td_proc->p_fd;
int i;
struct file *fp;
int n = 0;
FILEDESC_LOCK(fdp);
for (i = 0; i < nfd; i++, fds++) {
if (fds->fd >= fdp->fd_nfiles) {
fds->revents = POLLNVAL;
n++;
} else if (fds->fd < 0) {
fds->revents = 0;
} else {
fp = fdp->fd_ofiles[fds->fd];
if (fp == NULL) {
fds->revents = POLLNVAL;
n++;
} else {
/*
* Note: backend also returns POLLHUP and
* POLLERR if appropriate.
*/
fds->revents = fo_poll(fp, fds->events,
td->td_ucred, td);
if (fds->revents != 0)
n++;
}
}
}
FILEDESC_UNLOCK(fdp);
td->td_retval[0] = n;
return (0);
}
/*
* OpenBSD poll system call.
* XXX this isn't quite a true representation.. OpenBSD uses select ops.
*/
#ifndef _SYS_SYSPROTO_H_
struct openbsd_poll_args {
struct pollfd *fds;
u_int nfds;
int timeout;
};
#endif
/*
* MPSAFE
*/
int
openbsd_poll(td, uap)
register struct thread *td;
register struct openbsd_poll_args *uap;
{
return (poll(td, (struct poll_args *)uap));
}
/*
* Remove the references to the thread from all of the objects
* we were polling.
*
* This code assumes that the underlying owner of the selinfo
* structure will hold sellock before it changes it, and that
* it will unlink itself from our list if it goes away.
*/
void
clear_selinfo_list(td)
struct thread *td;
{
struct selinfo *si;
mtx_assert(&sellock, MA_OWNED);
TAILQ_FOREACH(si, &td->td_selq, si_thrlist)
si->si_thread = NULL;
TAILQ_INIT(&td->td_selq);
}
/*
* Record a select request.
*/
void
selrecord(selector, sip)
struct thread *selector;
struct selinfo *sip;
{
mtx_lock(&sellock);
/*
* If the selinfo's thread pointer is NULL then take ownership of it.
*
* If the thread pointer is not NULL and it points to another
* thread, then we have a collision.
*
* If the thread pointer is not NULL and points back to us then leave
* it alone as we've already added pointed it at us and added it to
* our list.
*/
if (sip->si_thread == NULL) {
sip->si_thread = selector;
TAILQ_INSERT_TAIL(&selector->td_selq, sip, si_thrlist);
} else if (sip->si_thread != selector) {
sip->si_flags |= SI_COLL;
}
mtx_unlock(&sellock);
}
/* Wake up a selecting thread. */
void
selwakeup(sip)
struct selinfo *sip;
{
doselwakeup(sip, -1);
}
/* Wake up a selecting thread, and set its priority. */
void
selwakeuppri(sip, pri)
struct selinfo *sip;
int pri;
{
doselwakeup(sip, pri);
}
/*
* Do a wakeup when a selectable event occurs.
*/
static void
doselwakeup(sip, pri)
struct selinfo *sip;
int pri;
{
struct thread *td;
mtx_lock(&sellock);
td = sip->si_thread;
if ((sip->si_flags & SI_COLL) != 0) {
nselcoll++;
sip->si_flags &= ~SI_COLL;
cv_broadcastpri(&selwait, pri);
}
if (td == NULL) {
mtx_unlock(&sellock);
return;
}
TAILQ_REMOVE(&td->td_selq, sip, si_thrlist);
sip->si_thread = NULL;
mtx_lock_spin(&sched_lock);
td->td_flags &= ~TDF_SELECT;
mtx_unlock_spin(&sched_lock);
sleepq_remove(td, &selwait);
mtx_unlock(&sellock);
}
static void selectinit(void *);
SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, selectinit, NULL)
/* ARGSUSED*/
static void
selectinit(dummy)
void *dummy;
{
cv_init(&selwait, "select");
mtx_init(&sellock, "sellck", NULL, MTX_DEF);
}
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