/* $OpenBSD: sys_generic.c,v 1.78 2012/07/09 17:51:08 claudio 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef KTRACE #include #endif #include #include #include #include int selscan(struct proc *, fd_set *, fd_set *, int, int, register_t *); void pollscan(struct proc *, struct pollfd *, u_int, register_t *); int pollout(struct pollfd *, struct pollfd *, u_int); /* * 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; struct iovec iov; 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); iov.iov_base = SCARG(uap, buf); iov.iov_len = SCARG(uap, nbyte); FREF(fp); /* dofilereadv() will FRELE the descriptor for us */ return (dofilereadv(p, fd, fp, &iov, 1, 0, &fp->f_offset, retval)); } /* * 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), 1, &fp->f_offset, retval)); } int dofilereadv(struct proc *p, int fd, struct file *fp, const struct iovec *iovp, int iovcnt, int userspace, off_t *offset, register_t *retval) { struct iovec aiov[UIO_SMALLIOV]; struct uio auio; struct iovec *iov; struct iovec *needfree = NULL; 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 the iovec array exists in userspace, it needs to be copied in; * otherwise, it can be used directly. */ if (userspace) { 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; } if ((error = copyin(iovp, iov, iovlen))) goto done; } else { iov = (struct iovec *)iovp; /* de-constify */ } auio.uio_iov = iov; auio.uio_iovcnt = iovcnt; auio.uio_rw = UIO_READ; auio.uio_segflg = UIO_USERSPACE; auio.uio_procp = p; 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. Note that the addition is * guaranteed to not wrap because SSIZE_MAX * 2 < SIZE_MAX. */ 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, p); 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; struct iovec iov; 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); iov.iov_base = (void *)SCARG(uap, buf); iov.iov_len = SCARG(uap, nbyte); FREF(fp); /* dofilewritev() will FRELE the descriptor for us */ return (dofilewritev(p, fd, fp, &iov, 1, 0, &fp->f_offset, retval)); } /* * 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), 1, &fp->f_offset, retval)); } int dofilewritev(struct proc *p, int fd, struct file *fp, const struct iovec *iovp, int iovcnt, int userspace, off_t *offset, register_t *retval) { struct iovec aiov[UIO_SMALLIOV]; struct uio auio; struct iovec *iov; struct iovec *needfree = NULL; 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 the iovec array exists in userspace, it needs to be copied in; * otherwise, it can be used directly. */ if (userspace) { 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; } if ((error = copyin(iovp, iov, iovlen))) goto done; } else { iov = (struct iovec *)iovp; /* de-constify */ } auio.uio_iov = iov; auio.uio_iovcnt = iovcnt; auio.uio_rw = UIO_WRITE; auio.uio_segflg = UIO_USERSPACE; auio.uio_procp = p; 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. Note that the addition is * guaranteed to not wrap because SSIZE_MAX * 2 < SIZE_MAX. */ 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) ptsignal(p, SIGPIPE, STHREAD); } 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, p); 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 long long stkbuf[STK_PARAMS / sizeof(long long)]; 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: case FIOCLEX: fdplock(fdp); if (com == FIONCLEX) fdp->fd_ofileflags[SCARG(uap, fd)] &= ~UF_EXCLOSE; else fdp->fd_ofileflags[SCARG(uap, fd)] |= UF_EXCLOSE; fdpunlock(fdp); 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 = (caddr_t)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 process *pr = prfind(tmp); if (pr == NULL) { error = ESRCH; break; } tmp = pr->ps_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, p); 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 (ni > sizeof(bits[0])) { caddr_t mbits; mbits = malloc(ni * 6, M_TEMP, M_WAITOK|M_ZERO); 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 #ifdef KTRACE if (ni > 0 && KTRPOINT(p, KTR_STRUCT)) { if (SCARG(uap, in)) ktrfdset(p, pibits[0], ni); if (SCARG(uap, ou)) ktrfdset(p, pibits[1], ni); if (SCARG(uap, ex)) ktrfdset(p, pibits[2], ni); } #endif if (SCARG(uap, tv)) { error = copyin(SCARG(uap, tv), &atv, sizeof (atv)); if (error) goto done; #ifdef KTRACE if (KTRPOINT(p, KTR_STRUCT)) ktrreltimeval(p, &atv); #endif 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 #ifdef KTRACE if (ni > 0 && KTRPOINT(p, KTR_STRUCT)) { if (SCARG(uap, in)) ktrfdset(p, pobits[0], ni); if (SCARG(uap, ou)) ktrfdset(p, pobits[1], ni); if (SCARG(uap, ex)) ktrfdset(p, pobits[2], ni); } #endif } 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, p); } } } *retval = n; return (0); } /*ARGSUSED*/ int seltrue(dev_t dev, int events, struct proc *p) { return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); } int selfalse(dev_t dev, int events, struct proc *p) { return (0); } /* * 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; KNOTE(&sip->si_note, 0); 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, p); if (pl->revents != 0) n++; } *retval = n; } /* * Only copyout the revents field. */ int pollout(struct pollfd *pl, struct pollfd *upl, u_int nfds) { int error = 0; u_int i = 0; while (!error && i++ < nfds) { error = copyout(&pl->revents, &upl->revents, sizeof(upl->revents)); pl++; upl++; } return (error); } /* * 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 = pollout(pl, SCARG(uap, fds), nfds); if (error == 0) error = EINTR; break; case EWOULDBLOCK: case 0: error = pollout(pl, SCARG(uap, fds), nfds); break; } bad: if (pl != pfds) free(pl, M_TEMP); return (error); }