/* $OpenBSD: sys_generic.c,v 1.57 2007/07/25 23:11:52 art Exp $ */
/* $NetBSD: sys_generic.c,v 1.24 1996/03/29 00:25:32 cgd Exp $ */
/*
* Copyright (c) 1996 Theo de Raadt
* 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.
* 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.
*
* @(#)sys_generic.c 8.5 (Berkeley) 1/21/94
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/ioctl.h>
#include <sys/file.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/socketvar.h>
#include <sys/signalvar.h>
#include <sys/uio.h>
#include <sys/kernel.h>
#include <sys/stat.h>
#include <sys/malloc.h>
#include <sys/poll.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#include <sys/sched.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <uvm/uvm_extern.h>
int selscan(struct proc *, fd_set *, fd_set *, int, int, register_t *);
int seltrue(dev_t, int, struct proc *);
void pollscan(struct proc *, struct pollfd *, u_int, register_t *);
/*
* Read system call.
*/
/* ARGSUSED */
int
sys_read(struct proc *p, void *v, register_t *retval)
{
struct sys_read_args /* {
syscallarg(int) fd;
syscallarg(void *) buf;
syscallarg(size_t) nbyte;
} */ *uap = v;
int fd = SCARG(uap, fd);
struct file *fp;
struct filedesc *fdp = p->p_fd;
if ((fp = fd_getfile(fdp, fd)) == NULL)
return (EBADF);
if ((fp->f_flag & FREAD) == 0)
return (EBADF);
FREF(fp);
/* dofileread() will FRELE the descriptor for us */
return (dofileread(p, fd, fp, SCARG(uap, buf), SCARG(uap, nbyte),
&fp->f_offset, retval));
}
int
dofileread(struct proc *p, int fd, struct file *fp, void *buf, size_t nbyte,
off_t *offset, register_t *retval)
{
struct uio auio;
struct iovec aiov;
long cnt, error = 0;
#ifdef KTRACE
struct iovec ktriov;
#endif
aiov.iov_base = buf;
aiov.iov_len = nbyte;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_resid = nbyte;
auio.uio_rw = UIO_READ;
auio.uio_segflg = UIO_USERSPACE;
auio.uio_procp = p;
/*
* Reads return ssize_t because -1 is returned on error. Therefore
* we must restrict the length to SSIZE_MAX to avoid garbage return
* values.
*/
if (auio.uio_resid > SSIZE_MAX) {
error = EINVAL;
goto out;
}
#ifdef KTRACE
/*
* if tracing, save a copy of iovec
*/
if (KTRPOINT(p, KTR_GENIO))
ktriov = aiov;
#endif
cnt = auio.uio_resid;
error = (*fp->f_ops->fo_read)(fp, offset, &auio, fp->f_cred);
if (error)
if (auio.uio_resid != cnt && (error == ERESTART ||
error == EINTR || error == EWOULDBLOCK))
error = 0;
cnt -= auio.uio_resid;
fp->f_rxfer++;
fp->f_rbytes += cnt;
#ifdef KTRACE
if (KTRPOINT(p, KTR_GENIO) && error == 0)
ktrgenio(p, fd, UIO_READ, &ktriov, cnt, error);
#endif
*retval = cnt;
out:
FRELE(fp);
return (error);
}
/*
* Scatter read system call.
*/
int
sys_readv(struct proc *p, void *v, register_t *retval)
{
struct sys_readv_args /* {
syscallarg(int) fd;
syscallarg(const struct iovec *) iovp;
syscallarg(int) iovcnt;
} */ *uap = v;
int fd = SCARG(uap, fd);
struct file *fp;
struct filedesc *fdp = p->p_fd;
if ((fp = fd_getfile(fdp, fd)) == NULL)
return (EBADF);
if ((fp->f_flag & FREAD) == 0)
return (EBADF);
FREF(fp);
/* dofilereadv() will FRELE the descriptor for us */
return (dofilereadv(p, fd, fp, SCARG(uap, iovp), SCARG(uap, iovcnt),
&fp->f_offset, retval));
}
int
dofilereadv(struct proc *p, int fd, struct file *fp, const struct iovec *iovp,
int iovcnt, off_t *offset, register_t *retval)
{
struct uio auio;
struct iovec *iov;
struct iovec *needfree;
struct iovec aiov[UIO_SMALLIOV];
long i, cnt, error = 0;
u_int iovlen;
#ifdef KTRACE
struct iovec *ktriov = NULL;
#endif
/* note: can't use iovlen until iovcnt is validated */
iovlen = iovcnt * sizeof(struct iovec);
if ((u_int)iovcnt > UIO_SMALLIOV) {
if ((u_int)iovcnt > IOV_MAX) {
error = EINVAL;
goto out;
}
iov = needfree = malloc(iovlen, M_IOV, M_WAITOK);
} else if ((u_int)iovcnt > 0) {
iov = aiov;
needfree = NULL;
} else {
error = EINVAL;
goto out;
}
auio.uio_iov = iov;
auio.uio_iovcnt = iovcnt;
auio.uio_rw = UIO_READ;
auio.uio_segflg = UIO_USERSPACE;
auio.uio_procp = p;
error = copyin(iovp, iov, iovlen);
if (error)
goto done;
auio.uio_resid = 0;
for (i = 0; i < iovcnt; i++) {
auio.uio_resid += iov->iov_len;
/*
* Reads return ssize_t because -1 is returned on error.
* Therefore we must restrict the length to SSIZE_MAX to
* avoid garbage return values.
*/
if (iov->iov_len > SSIZE_MAX || auio.uio_resid > SSIZE_MAX) {
error = EINVAL;
goto done;
}
iov++;
}
#ifdef KTRACE
/*
* if tracing, save a copy of iovec
*/
if (KTRPOINT(p, KTR_GENIO)) {
ktriov = malloc(iovlen, M_TEMP, M_WAITOK);
bcopy(auio.uio_iov, ktriov, iovlen);
}
#endif
cnt = auio.uio_resid;
error = (*fp->f_ops->fo_read)(fp, offset, &auio, fp->f_cred);
if (error)
if (auio.uio_resid != cnt && (error == ERESTART ||
error == EINTR || error == EWOULDBLOCK))
error = 0;
cnt -= auio.uio_resid;
fp->f_rxfer++;
fp->f_rbytes += cnt;
#ifdef KTRACE
if (ktriov != NULL) {
if (error == 0)
ktrgenio(p, fd, UIO_READ, ktriov, cnt,
error);
free(ktriov, M_TEMP);
}
#endif
*retval = cnt;
done:
if (needfree)
free(needfree, M_IOV);
out:
FRELE(fp);
return (error);
}
/*
* Write system call
*/
int
sys_write(struct proc *p, void *v, register_t *retval)
{
struct sys_write_args /* {
syscallarg(int) fd;
syscallarg(const void *) buf;
syscallarg(size_t) nbyte;
} */ *uap = v;
int fd = SCARG(uap, fd);
struct file *fp;
struct filedesc *fdp = p->p_fd;
if ((fp = fd_getfile(fdp, fd)) == NULL)
return (EBADF);
if ((fp->f_flag & FWRITE) == 0)
return (EBADF);
FREF(fp);
/* dofilewrite() will FRELE the descriptor for us */
return (dofilewrite(p, fd, fp, SCARG(uap, buf), SCARG(uap, nbyte),
&fp->f_offset, retval));
}
int
dofilewrite(struct proc *p, int fd, struct file *fp, const void *buf,
size_t nbyte, off_t *offset, register_t *retval)
{
struct uio auio;
struct iovec aiov;
long cnt, error = 0;
#ifdef KTRACE
struct iovec ktriov;
#endif
aiov.iov_base = (void *)buf; /* XXX kills const */
aiov.iov_len = nbyte;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_resid = nbyte;
auio.uio_rw = UIO_WRITE;
auio.uio_segflg = UIO_USERSPACE;
auio.uio_procp = p;
/*
* Writes return ssize_t because -1 is returned on error. Therefore
* we must restrict the length to SSIZE_MAX to avoid garbage return
* values.
*/
if (auio.uio_resid > SSIZE_MAX) {
error = EINVAL;
goto out;
}
#ifdef KTRACE
/*
* if tracing, save a copy of iovec
*/
if (KTRPOINT(p, KTR_GENIO))
ktriov = aiov;
#endif
cnt = auio.uio_resid;
error = (*fp->f_ops->fo_write)(fp, offset, &auio, fp->f_cred);
if (error) {
if (auio.uio_resid != cnt && (error == ERESTART ||
error == EINTR || error == EWOULDBLOCK))
error = 0;
if (error == EPIPE)
psignal(p, SIGPIPE);
}
cnt -= auio.uio_resid;
fp->f_wxfer++;
fp->f_wbytes += cnt;
#ifdef KTRACE
if (KTRPOINT(p, KTR_GENIO) && error == 0)
ktrgenio(p, fd, UIO_WRITE, &ktriov, cnt, error);
#endif
*retval = cnt;
out:
FRELE(fp);
return (error);
}
/*
* Gather write system call
*/
int
sys_writev(struct proc *p, void *v, register_t *retval)
{
struct sys_writev_args /* {
syscallarg(int) fd;
syscallarg(const struct iovec *) iovp;
syscallarg(int) iovcnt;
} */ *uap = v;
int fd = SCARG(uap, fd);
struct file *fp;
struct filedesc *fdp = p->p_fd;
if ((fp = fd_getfile(fdp, fd)) == NULL)
return (EBADF);
if ((fp->f_flag & FWRITE) == 0)
return (EBADF);
FREF(fp);
/* dofilewritev() will FRELE the descriptor for us */
return (dofilewritev(p, fd, fp, SCARG(uap, iovp), SCARG(uap, iovcnt),
&fp->f_offset, retval));
}
int
dofilewritev(struct proc *p, int fd, struct file *fp, const struct iovec *iovp,
int iovcnt, off_t *offset, register_t *retval)
{
struct uio auio;
struct iovec *iov;
struct iovec *needfree;
struct iovec aiov[UIO_SMALLIOV];
long i, cnt, error = 0;
u_int iovlen;
#ifdef KTRACE
struct iovec *ktriov = NULL;
#endif
/* note: can't use iovlen until iovcnt is validated */
iovlen = iovcnt * sizeof(struct iovec);
if ((u_int)iovcnt > UIO_SMALLIOV) {
if ((u_int)iovcnt > IOV_MAX) {
error = EINVAL;
goto out;
}
iov = needfree = malloc(iovlen, M_IOV, M_WAITOK);
} else if ((u_int)iovcnt > 0) {
iov = aiov;
needfree = NULL;
} else {
error = EINVAL;
goto out;
}
auio.uio_iov = iov;
auio.uio_iovcnt = iovcnt;
auio.uio_rw = UIO_WRITE;
auio.uio_segflg = UIO_USERSPACE;
auio.uio_procp = p;
error = copyin(iovp, iov, iovlen);
if (error)
goto done;
auio.uio_resid = 0;
for (i = 0; i < iovcnt; i++) {
auio.uio_resid += iov->iov_len;
/*
* Writes return ssize_t because -1 is returned on error.
* Therefore we must restrict the length to SSIZE_MAX to
* avoid garbage return values.
*/
if (iov->iov_len > SSIZE_MAX || auio.uio_resid > SSIZE_MAX) {
error = EINVAL;
goto done;
}
iov++;
}
#ifdef KTRACE
/*
* if tracing, save a copy of iovec
*/
if (KTRPOINT(p, KTR_GENIO)) {
ktriov = malloc(iovlen, M_TEMP, M_WAITOK);
bcopy(auio.uio_iov, ktriov, iovlen);
}
#endif
cnt = auio.uio_resid;
error = (*fp->f_ops->fo_write)(fp, offset, &auio, fp->f_cred);
if (error) {
if (auio.uio_resid != cnt && (error == ERESTART ||
error == EINTR || error == EWOULDBLOCK))
error = 0;
if (error == EPIPE)
psignal(p, SIGPIPE);
}
cnt -= auio.uio_resid;
fp->f_wxfer++;
fp->f_wbytes += cnt;
#ifdef KTRACE
if (ktriov != NULL) {
if (error == 0)
ktrgenio(p, fd, UIO_WRITE, ktriov, cnt, error);
free(ktriov, M_TEMP);
}
#endif
*retval = cnt;
done:
if (needfree)
free(needfree, M_IOV);
out:
FRELE(fp);
return (error);
}
/*
* Ioctl system call
*/
/* ARGSUSED */
int
sys_ioctl(struct proc *p, void *v, register_t *retval)
{
struct sys_ioctl_args /* {
syscallarg(int) fd;
syscallarg(u_long) com;
syscallarg(void *) data;
} */ *uap = v;
struct file *fp;
struct filedesc *fdp;
u_long com;
int error;
u_int size;
caddr_t data, memp;
int tmp;
#define STK_PARAMS 128
char stkbuf[STK_PARAMS];
fdp = p->p_fd;
if ((fp = fd_getfile(fdp, SCARG(uap, fd))) == NULL)
return (EBADF);
if ((fp->f_flag & (FREAD | FWRITE)) == 0)
return (EBADF);
switch (com = SCARG(uap, com)) {
case FIONCLEX:
fdp->fd_ofileflags[SCARG(uap, fd)] &= ~UF_EXCLOSE;
return (0);
case FIOCLEX:
fdp->fd_ofileflags[SCARG(uap, fd)] |= UF_EXCLOSE;
return (0);
}
/*
* 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)
return (ENOTTY);
FREF(fp);
memp = NULL;
if (size > sizeof (stkbuf)) {
memp = (caddr_t)malloc((u_long)size, M_IOCTLOPS, M_WAITOK);
data = memp;
} else
data = stkbuf;
if (com&IOC_IN) {
if (size) {
error = copyin(SCARG(uap, data), data, (u_int)size);
if (error) {
goto out;
}
} else
*(caddr_t *)data = SCARG(uap, data);
} else if ((com&IOC_OUT) && size)
/*
* Zero the buffer so the user always
* gets back something deterministic.
*/
bzero(data, size);
else if (com&IOC_VOID)
*(caddr_t *)data = SCARG(uap, data);
switch (com) {
case FIONBIO:
if ((tmp = *(int *)data) != 0)
fp->f_flag |= FNONBLOCK;
else
fp->f_flag &= ~FNONBLOCK;
error = (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p);
break;
case FIOASYNC:
if ((tmp = *(int *)data) != 0)
fp->f_flag |= FASYNC;
else
fp->f_flag &= ~FASYNC;
error = (*fp->f_ops->fo_ioctl)(fp, FIOASYNC, (caddr_t)&tmp, p);
break;
case FIOSETOWN:
tmp = *(int *)data;
if (fp->f_type == DTYPE_SOCKET) {
struct socket *so = (struct socket *)fp->f_data;
so->so_pgid = tmp;
so->so_siguid = p->p_cred->p_ruid;
so->so_sigeuid = p->p_ucred->cr_uid;
error = 0;
break;
}
if (tmp <= 0) {
tmp = -tmp;
} else {
struct proc *p1 = pfind(tmp);
if (p1 == 0) {
error = ESRCH;
break;
}
tmp = p1->p_pgrp->pg_id;
}
error = (*fp->f_ops->fo_ioctl)
(fp, TIOCSPGRP, (caddr_t)&tmp, p);
break;
case FIOGETOWN:
if (fp->f_type == DTYPE_SOCKET) {
error = 0;
*(int *)data = ((struct socket *)fp->f_data)->so_pgid;
break;
}
error = (*fp->f_ops->fo_ioctl)(fp, TIOCGPGRP, data, p);
*(int *)data = -*(int *)data;
break;
default:
error = (*fp->f_ops->fo_ioctl)(fp, com, data, p);
break;
}
/*
* Copy any data to user, size was
* already set and checked above.
*/
if (error == 0 && (com&IOC_OUT) && size)
error = copyout(data, SCARG(uap, data), (u_int)size);
out:
FRELE(fp);
if (memp)
free(memp, M_IOCTLOPS);
return (error);
}
int selwait, nselcoll;
/*
* Select system call.
*/
int
sys_select(struct proc *p, void *v, register_t *retval)
{
struct sys_select_args /* {
syscallarg(int) nd;
syscallarg(fd_set *) in;
syscallarg(fd_set *) ou;
syscallarg(fd_set *) ex;
syscallarg(struct timeval *) tv;
} */ *uap = v;
fd_mask bits[6];
fd_set *pibits[3], *pobits[3];
struct timeval atv, rtv, ttv;
int s, ncoll, error = 0, timo;
u_int nd, ni;
nd = SCARG(uap, nd);
if (nd > p->p_fd->fd_nfiles) {
/* forgiving; slightly wrong */
nd = p->p_fd->fd_nfiles;
}
ni = howmany(nd, NFDBITS) * sizeof(fd_mask);
if (nd > sizeof(bits[0])) {
caddr_t mbits;
mbits = malloc(ni * 6, M_TEMP, M_WAITOK);
bzero(mbits, ni * 6);
pibits[0] = (fd_set *)&mbits[ni * 0];
pibits[1] = (fd_set *)&mbits[ni * 1];
pibits[2] = (fd_set *)&mbits[ni * 2];
pobits[0] = (fd_set *)&mbits[ni * 3];
pobits[1] = (fd_set *)&mbits[ni * 4];
pobits[2] = (fd_set *)&mbits[ni * 5];
} else {
bzero(bits, sizeof(bits));
pibits[0] = (fd_set *)&bits[0];
pibits[1] = (fd_set *)&bits[1];
pibits[2] = (fd_set *)&bits[2];
pobits[0] = (fd_set *)&bits[3];
pobits[1] = (fd_set *)&bits[4];
pobits[2] = (fd_set *)&bits[5];
}
#define getbits(name, x) \
if (SCARG(uap, name) && (error = copyin(SCARG(uap, name), \
pibits[x], ni))) \
goto done;
getbits(in, 0);
getbits(ou, 1);
getbits(ex, 2);
#undef getbits
if (SCARG(uap, tv)) {
error = copyin(SCARG(uap, tv), &atv, sizeof (atv));
if (error)
goto done;
if (itimerfix(&atv)) {
error = EINVAL;
goto done;
}
getmicrouptime(&rtv);
timeradd(&atv, &rtv, &atv);
} else {
atv.tv_sec = 0;
atv.tv_usec = 0;
}
timo = 0;
retry:
ncoll = nselcoll;
atomic_setbits_int(&p->p_flag, P_SELECT);
error = selscan(p, pibits[0], pobits[0], nd, ni, retval);
if (error || *retval)
goto done;
if (SCARG(uap, tv)) {
getmicrouptime(&rtv);
if (timercmp(&rtv, &atv, >=))
goto done;
ttv = atv;
timersub(&ttv, &rtv, &ttv);
timo = ttv.tv_sec > 24 * 60 * 60 ?
24 * 60 * 60 * hz : tvtohz(&ttv);
}
s = splhigh();
if ((p->p_flag & P_SELECT) == 0 || nselcoll != ncoll) {
splx(s);
goto retry;
}
atomic_clearbits_int(&p->p_flag, P_SELECT);
error = tsleep(&selwait, PSOCK | PCATCH, "select", timo);
splx(s);
if (error == 0)
goto retry;
done:
atomic_clearbits_int(&p->p_flag, P_SELECT);
/* select is not restarted after signals... */
if (error == ERESTART)
error = EINTR;
if (error == EWOULDBLOCK)
error = 0;
#define putbits(name, x) \
if (SCARG(uap, name) && (error2 = copyout(pobits[x], \
SCARG(uap, name), ni))) \
error = error2;
if (error == 0) {
int error2;
putbits(in, 0);
putbits(ou, 1);
putbits(ex, 2);
#undef putbits
}
if (pibits[0] != (fd_set *)&bits[0])
free(pibits[0], M_TEMP);
return (error);
}
int
selscan(struct proc *p, fd_set *ibits, fd_set *obits, int nfd, int ni,
register_t *retval)
{
caddr_t cibits = (caddr_t)ibits, cobits = (caddr_t)obits;
struct filedesc *fdp = p->p_fd;
int msk, i, j, fd;
fd_mask bits;
struct file *fp;
int n = 0;
static const int flag[3] = { POLLIN, POLLOUT, POLLPRI };
for (msk = 0; msk < 3; msk++) {
fd_set *pibits = (fd_set *)&cibits[msk*ni];
fd_set *pobits = (fd_set *)&cobits[msk*ni];
for (i = 0; i < nfd; i += NFDBITS) {
bits = pibits->fds_bits[i/NFDBITS];
while ((j = ffs(bits)) && (fd = i + --j) < nfd) {
bits &= ~(1 << j);
if ((fp = fd_getfile(fdp, fd)) == NULL)
return (EBADF);
FREF(fp);
if ((*fp->f_ops->fo_poll)(fp, flag[msk], p)) {
FD_SET(fd, pobits);
n++;
}
FRELE(fp);
}
}
}
*retval = n;
return (0);
}
/*ARGSUSED*/
int
seltrue(dev_t dev, int events, struct proc *p)
{
return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
}
/*
* Record a select request.
*/
void
selrecord(struct proc *selector, struct selinfo *sip)
{
struct proc *p;
pid_t mypid;
mypid = selector->p_pid;
if (sip->si_selpid == mypid)
return;
if (sip->si_selpid && (p = pfind(sip->si_selpid)) &&
p->p_wchan == (caddr_t)&selwait)
sip->si_flags |= SI_COLL;
else
sip->si_selpid = mypid;
}
/*
* Do a wakeup when a selectable event occurs.
*/
void
selwakeup(struct selinfo *sip)
{
struct proc *p;
int s;
if (sip->si_selpid == 0)
return;
if (sip->si_flags & SI_COLL) {
nselcoll++;
sip->si_flags &= ~SI_COLL;
wakeup(&selwait);
}
p = pfind(sip->si_selpid);
sip->si_selpid = 0;
if (p != NULL) {
SCHED_LOCK(s);
if (p->p_wchan == (caddr_t)&selwait) {
if (p->p_stat == SSLEEP)
setrunnable(p);
else
unsleep(p);
} else if (p->p_flag & P_SELECT)
atomic_clearbits_int(&p->p_flag, P_SELECT);
SCHED_UNLOCK(s);
}
}
void
pollscan(struct proc *p, struct pollfd *pl, u_int nfd, register_t *retval)
{
struct filedesc *fdp = p->p_fd;
struct file *fp;
u_int i;
int n = 0;
for (i = 0; i < nfd; i++, pl++) {
/* Check the file descriptor. */
if (pl->fd < 0) {
pl->revents = 0;
continue;
}
if ((fp = fd_getfile(fdp, pl->fd)) == NULL) {
pl->revents = POLLNVAL;
n++;
continue;
}
FREF(fp);
pl->revents = (*fp->f_ops->fo_poll)(fp, pl->events, p);
FRELE(fp);
if (pl->revents != 0)
n++;
}
*retval = n;
}
/*
* We are using the same mechanism as select only we encode/decode args
* differently.
*/
int
sys_poll(struct proc *p, void *v, register_t *retval)
{
struct sys_poll_args /* {
syscallarg(struct pollfd *) fds;
syscallarg(u_int) nfds;
syscallarg(int) timeout;
} */ *uap = v;
size_t sz;
struct pollfd pfds[4], *pl = pfds;
int msec = SCARG(uap, timeout);
struct timeval atv, rtv, ttv;
int timo, ncoll, i, s, error;
extern int nselcoll, selwait;
u_int nfds = SCARG(uap, nfds);
/* Standards say no more than MAX_OPEN; this is possibly better. */
if (nfds > min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles))
return (EINVAL);
sz = sizeof(struct pollfd) * nfds;
/* optimize for the default case, of a small nfds value */
if (sz > sizeof(pfds))
pl = (struct pollfd *) malloc(sz, M_TEMP, M_WAITOK);
if ((error = copyin(SCARG(uap, fds), pl, sz)) != 0)
goto bad;
for (i = 0; i < nfds; i++)
pl[i].revents = 0;
if (msec != INFTIM) {
atv.tv_sec = msec / 1000;
atv.tv_usec = (msec - (atv.tv_sec * 1000)) * 1000;
if (itimerfix(&atv)) {
error = EINVAL;
goto done;
}
getmicrouptime(&rtv);
timeradd(&atv, &rtv, &atv);
} else {
atv.tv_sec = 0;
atv.tv_usec = 0;
}
timo = 0;
retry:
ncoll = nselcoll;
atomic_setbits_int(&p->p_flag, P_SELECT);
pollscan(p, pl, nfds, retval);
if (*retval)
goto done;
if (msec != INFTIM) {
getmicrouptime(&rtv);
if (timercmp(&rtv, &atv, >=))
goto done;
ttv = atv;
timersub(&ttv, &rtv, &ttv);
timo = ttv.tv_sec > 24 * 60 * 60 ?
24 * 60 * 60 * hz : tvtohz(&ttv);
}
s = splhigh();
if ((p->p_flag & P_SELECT) == 0 || nselcoll != ncoll) {
splx(s);
goto retry;
}
atomic_clearbits_int(&p->p_flag, P_SELECT);
error = tsleep(&selwait, PSOCK | PCATCH, "poll", timo);
splx(s);
if (error == 0)
goto retry;
done:
atomic_clearbits_int(&p->p_flag, P_SELECT);
/*
* NOTE: poll(2) is not restarted after a signal and EWOULDBLOCK is
* ignored (since the whole point is to see what would block).
*/
switch (error) {
case ERESTART:
error = copyout(pl, SCARG(uap, fds), sz);
if (error == 0)
error = EINTR;
break;
case EWOULDBLOCK:
case 0:
error = copyout(pl, SCARG(uap, fds), sz);
break;
}
bad:
if (pl != pfds)
free(pl, M_TEMP);
return (error);
}
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