/* * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 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 * $FreeBSD$ */ #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/malloc.h> #include <sys/poll.h> #include <sys/resourcevar.h> #include <sys/selinfo.h> #include <sys/syscallsubr.h> #include <sys/sysctl.h> #include <sys/sysent.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> #include <machine/limits.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 *, struct file *, int, void *, size_t, off_t, int); static int dofilewrite(struct thread *, struct file *, int, const void *, size_t, off_t, 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 file *fp; int error; if ((error = fget_read(td, uap->fd, &fp)) == 0) { error = dofileread(td, fp, uap->fd, uap->buf, uap->nbyte, (off_t)-1, 0); fdrop(fp, td); } return(error); } /* * Pread 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 file *fp; int error; if ((error = fget_read(td, uap->fd, &fp)) != 0) return (error); if (fp->f_type != DTYPE_VNODE) { error = ESPIPE; } else { error = dofileread(td, fp, uap->fd, uap->buf, uap->nbyte, uap->offset, FOF_OFFSET); } fdrop(fp, td); return(error); } /* * Code common for read and pread */ static int dofileread(td, fp, fd, buf, nbyte, offset, flags) struct thread *td; struct file *fp; int fd, flags; void *buf; size_t nbyte; off_t offset; { struct uio auio; struct iovec aiov; long cnt, error = 0; #ifdef KTRACE struct iovec ktriov; struct uio ktruio; int didktr = 0; #endif aiov.iov_base = buf; aiov.iov_len = nbyte; auio.uio_iov = &aiov; auio.uio_iovcnt = 1; auio.uio_offset = offset; if (nbyte > INT_MAX) return (EINVAL); auio.uio_resid = nbyte; auio.uio_rw = UIO_READ; auio.uio_segflg = UIO_USERSPACE; auio.uio_td = td; #ifdef KTRACE /* * if tracing, save a copy of iovec */ if (KTRPOINT(td, KTR_GENIO)) { ktriov = aiov; ktruio = auio; didktr = 1; } #endif cnt = nbyte; 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 (didktr && error == 0) { ktruio.uio_iov = &ktriov; ktruio.uio_resid = cnt; ktrgenio(fd, UIO_READ, &ktruio, error); } #endif td->td_retval[0] = cnt; 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(td, uap) struct thread *td; struct readv_args *uap; { struct file *fp; struct uio auio; struct iovec *iov; struct iovec *needfree; struct iovec aiov[UIO_SMALLIOV]; long i, cnt; int error; u_int iovlen; #ifdef KTRACE struct iovec *ktriov = NULL; struct uio ktruio; #endif if ((error = fget_read(td, uap->fd, &fp)) != 0) return (error); needfree = NULL; /* note: can't use iovlen until iovcnt is validated */ iovlen = uap->iovcnt * sizeof (struct iovec); if (uap->iovcnt > UIO_SMALLIOV) { if (uap->iovcnt > UIO_MAXIOV) { error = EINVAL; goto done; } MALLOC(iov, struct iovec *, iovlen, M_IOV, 0); needfree = iov; } else iov = aiov; auio.uio_iov = iov; auio.uio_iovcnt = uap->iovcnt; auio.uio_rw = UIO_READ; auio.uio_segflg = UIO_USERSPACE; auio.uio_td = td; auio.uio_offset = -1; if ((error = copyin(uap->iovp, iov, iovlen))) goto done; auio.uio_resid = 0; for (i = 0; i < uap->iovcnt; i++) { if (iov->iov_len > INT_MAX - auio.uio_resid) { error = EINVAL; goto done; } auio.uio_resid += iov->iov_len; iov++; } #ifdef KTRACE /* * if tracing, save a copy of iovec */ if (KTRPOINT(td, KTR_GENIO)) { MALLOC(ktriov, struct iovec *, iovlen, M_TEMP, 0); bcopy(auio.uio_iov, ktriov, iovlen); ktruio = auio; } #endif cnt = auio.uio_resid; if ((error = fo_read(fp, &auio, td->td_ucred, 0, td))) { if (auio.uio_resid != cnt && (error == ERESTART || error == EINTR || error == EWOULDBLOCK)) error = 0; } cnt -= auio.uio_resid; #ifdef KTRACE if (ktriov != NULL) { if (error == 0) { ktruio.uio_iov = ktriov; ktruio.uio_resid = cnt; ktrgenio(uap->fd, UIO_READ, &ktruio, error); } FREE(ktriov, M_TEMP); } #endif td->td_retval[0] = cnt; done: fdrop(fp, td); if (needfree) FREE(needfree, M_IOV); 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 file *fp; int error; if ((error = fget_write(td, uap->fd, &fp)) == 0) { error = dofilewrite(td, fp, uap->fd, uap->buf, uap->nbyte, (off_t)-1, 0); fdrop(fp, td); } else { error = EBADF; /* XXX this can't be right */ } return(error); } /* * Pwrite 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 file *fp; int error; if ((error = fget_write(td, uap->fd, &fp)) == 0) { if (fp->f_type == DTYPE_VNODE) { error = dofilewrite(td, fp, uap->fd, uap->buf, uap->nbyte, uap->offset, FOF_OFFSET); } else { error = ESPIPE; } fdrop(fp, td); } else { error = EBADF; /* this can't be right */ } return(error); } static int dofilewrite(td, fp, fd, buf, nbyte, offset, flags) struct thread *td; struct file *fp; int fd, flags; const void *buf; size_t nbyte; off_t offset; { struct uio auio; struct iovec aiov; long cnt, error = 0; #ifdef KTRACE struct iovec ktriov; struct uio ktruio; int didktr = 0; #endif aiov.iov_base = (void *)(uintptr_t)buf; aiov.iov_len = nbyte; auio.uio_iov = &aiov; auio.uio_iovcnt = 1; auio.uio_offset = offset; if (nbyte > INT_MAX) return (EINVAL); auio.uio_resid = nbyte; auio.uio_rw = UIO_WRITE; auio.uio_segflg = UIO_USERSPACE; auio.uio_td = td; #ifdef KTRACE /* * if tracing, save a copy of iovec and uio */ if (KTRPOINT(td, KTR_GENIO)) { ktriov = aiov; ktruio = auio; didktr = 1; } #endif cnt = nbyte; 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 && fp->f_type != DTYPE_SOCKET) { PROC_LOCK(td->td_proc); psignal(td->td_proc, SIGPIPE); PROC_UNLOCK(td->td_proc); } } cnt -= auio.uio_resid; #ifdef KTRACE if (didktr && error == 0) { ktruio.uio_iov = &ktriov; ktruio.uio_resid = cnt; ktrgenio(fd, UIO_WRITE, &ktruio, error); } #endif td->td_retval[0] = cnt; 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(td, uap) struct thread *td; register struct writev_args *uap; { struct file *fp; struct uio auio; register 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; struct uio ktruio; #endif mtx_lock(&Giant); if ((error = fget_write(td, uap->fd, &fp)) != 0) { error = EBADF; goto done2; } /* note: can't use iovlen until iovcnt is validated */ iovlen = uap->iovcnt * sizeof (struct iovec); if (uap->iovcnt > UIO_SMALLIOV) { if (uap->iovcnt > UIO_MAXIOV) { needfree = NULL; error = EINVAL; goto done; } MALLOC(iov, struct iovec *, iovlen, M_IOV, 0); needfree = iov; } else { iov = aiov; needfree = NULL; } auio.uio_iov = iov; auio.uio_iovcnt = uap->iovcnt; auio.uio_rw = UIO_WRITE; auio.uio_segflg = UIO_USERSPACE; auio.uio_td = td; auio.uio_offset = -1; if ((error = copyin(uap->iovp, iov, iovlen))) goto done; auio.uio_resid = 0; for (i = 0; i < uap->iovcnt; i++) { if (iov->iov_len > INT_MAX - auio.uio_resid) { error = EINVAL; goto done; } auio.uio_resid += iov->iov_len; iov++; } #ifdef KTRACE /* * if tracing, save a copy of iovec and uio */ if (KTRPOINT(td, KTR_GENIO)) { MALLOC(ktriov, struct iovec *, iovlen, M_TEMP, 0); bcopy(auio.uio_iov, ktriov, iovlen); ktruio = auio; } #endif cnt = auio.uio_resid; if (fp->f_type == DTYPE_VNODE) bwillwrite(); if ((error = fo_write(fp, &auio, td->td_ucred, 0, td))) { if (auio.uio_resid != cnt && (error == ERESTART || error == EINTR || error == EWOULDBLOCK)) error = 0; 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 (ktriov != NULL) { if (error == 0) { ktruio.uio_iov = ktriov; ktruio.uio_resid = cnt; ktrgenio(uap->fd, UIO_WRITE, &ktruio, error); } FREE(ktriov, M_TEMP); } #endif td->td_retval[0] = cnt; done: fdrop(fp, td); if (needfree) FREE(needfree, M_IOV); done2: mtx_unlock(&Giant); 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(td, uap) struct thread *td; register struct ioctl_args *uap; { struct file *fp; register struct filedesc *fdp; register u_long com; int error = 0; register u_int size; caddr_t data, memp; int tmp; #define STK_PARAMS 128 union { char stkbuf[STK_PARAMS]; long align; } ubuf; if ((error = fget(td, uap->fd, &fp)) != 0) return (error); mtx_lock(&Giant); if ((fp->f_flag & (FREAD | FWRITE)) == 0) { fdrop(fp, td); mtx_unlock(&Giant); return (EBADF); } fdp = td->td_proc->p_fd; switch (com = uap->com) { case FIONCLEX: FILEDESC_LOCK(fdp); fdp->fd_ofileflags[uap->fd] &= ~UF_EXCLOSE; FILEDESC_UNLOCK(fdp); fdrop(fp, td); mtx_unlock(&Giant); return (0); case FIOCLEX: FILEDESC_LOCK(fdp); fdp->fd_ofileflags[uap->fd] |= UF_EXCLOSE; FILEDESC_UNLOCK(fdp); fdrop(fp, td); mtx_unlock(&Giant); 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) { fdrop(fp, td); mtx_unlock(&Giant); return (ENOTTY); } memp = NULL; if (size > sizeof (ubuf.stkbuf)) { memp = malloc((u_long)size, M_IOCTLOPS, 0); data = memp; } else { data = ubuf.stkbuf; } if (com&IOC_IN) { if (size) { error = copyin(uap->data, data, (u_int)size); if (error) { if (memp) free(memp, M_IOCTLOPS); fdrop(fp, td); goto done; } } else { *(caddr_t *)data = 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 = uap->data; } switch (com) { case FIONBIO: FILE_LOCK(fp); if ((tmp = *(int *)data)) fp->f_flag |= FNONBLOCK; else fp->f_flag &= ~FNONBLOCK; FILE_UNLOCK(fp); error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); break; case FIOASYNC: FILE_LOCK(fp); if ((tmp = *(int *)data)) fp->f_flag |= FASYNC; else fp->f_flag &= ~FASYNC; FILE_UNLOCK(fp); error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td); break; default: error = fo_ioctl(fp, com, data, td->td_ucred, td); /* * Copy any data to user, size was * already set and checked above. */ if (error == 0 && (com&IOC_OUT) && size) error = copyout(data, uap->data, (u_int)size); break; } if (memp) free(memp, M_IOCTLOPS); fdrop(fp, td); done: mtx_unlock(&Giant); 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; mtx_lock(&Giant); FILEDESC_LOCK(fdp); if (nd > td->td_proc->p_fd->fd_nfiles) nd = td->td_proc->p_fd->fd_nfiles; /* forgiving; slightly wrong */ FILEDESC_UNLOCK(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, 0); /* * 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); mtx_unlock(&Giant); 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; { caddr_t bits; char smallbits[32 * sizeof(struct pollfd)]; struct timeval atv, rtv, ttv; int error = 0, timo; u_int ncoll, nfds; size_t ni; nfds = uap->nfds; mtx_lock(&Giant); /* * 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. */ if ((nfds > td->td_proc->p_rlimit[RLIMIT_NOFILE].rlim_cur) && (nfds > FD_SETSIZE)) { error = EINVAL; goto done2; } ni = nfds * sizeof(struct pollfd); if (ni > sizeof(smallbits)) bits = malloc(ni, M_TEMP, 0); 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, (struct pollfd *)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: mtx_unlock(&Giant); 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); } /*ARGSUSED*/ int seltrue(dev, events, td) dev_t dev; int events; struct thread *td; { return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); } /* * 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); } /* * Do a wakeup when a selectable event occurs. */ void selwakeup(sip) struct selinfo *sip; { struct thread *td; mtx_lock(&sellock); td = sip->si_thread; if ((sip->si_flags & SI_COLL) != 0) { nselcoll++; sip->si_flags &= ~SI_COLL; cv_broadcast(&selwait); } if (td == NULL) { mtx_unlock(&sellock); return; } TAILQ_REMOVE(&td->td_selq, sip, si_thrlist); sip->si_thread = NULL; mtx_lock_spin(&sched_lock); if (td->td_wchan == &selwait) { cv_waitq_remove(td); TD_CLR_SLEEPING(td); setrunnable(td); } else td->td_flags &= ~TDF_SELECT; mtx_unlock_spin(&sched_lock); 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); }