sys_generic.c

早期freebsd实现

/*
 * 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
 */

#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/socketvar.h>
#include <sys/uio.h>
#include <sys/kernel.h>
#include <sys/stat.h>
#include <sys/malloc.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif

/*
 * Read system call.
 */
struct read_args {
	int	fd;
	char	*buf;
	u_int	nbyte;
};
/* ARGSUSED */
read(p, uap, retval)
	struct proc *p;
	register struct read_args *uap;
	int *retval;
{
	register struct file *fp;
	register struct filedesc *fdp = p->p_fd;
	struct uio auio;
	struct iovec aiov;
	long cnt, error = 0;
#ifdef KTRACE
	struct iovec ktriov;
#endif

	if (((u_int)uap->fd) >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[uap->fd]) == NULL ||
	    (fp->f_flag & FREAD) == 0)
		return (EBADF);
	aiov.iov_base = (caddr_t)uap->buf;
	aiov.iov_len = uap->nbyte;
	auio.uio_iov = &aiov;
	auio.uio_iovcnt = 1;
	auio.uio_resid = uap->nbyte;
	auio.uio_rw = UIO_READ;
	auio.uio_segflg = UIO_USERSPACE;
	auio.uio_procp = p;
#ifdef KTRACE
	/*
	 * if tracing, save a copy of iovec
	 */
	if (KTRPOINT(p, KTR_GENIO))
		ktriov = aiov;
#endif
	cnt = uap->nbyte;
	if (error = (*fp->f_ops->fo_read)(fp, &auio, fp->f_cred))
		if (auio.uio_resid != cnt && (error == ERESTART ||
		    error == EINTR || error == EWOULDBLOCK))
			error = 0;
	cnt -= auio.uio_resid;
#ifdef KTRACE
	if (KTRPOINT(p, KTR_GENIO) && error == 0)
		ktrgenio(p->p_tracep, uap->fd, UIO_READ, &ktriov, cnt, error);
#endif
	*retval = cnt;
	return (error);
}

/*
 * Scatter read system call.
 */
struct readv_args {
	int	fdes;
	struct	iovec *iovp;
	u_int	iovcnt;
};
readv(p, uap, retval)
	struct proc *p;
	register struct readv_args *uap;
	int *retval;
{
	register struct file *fp;
	register struct filedesc *fdp = p->p_fd;
	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;
#endif

	if (((u_int)uap->fdes) >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[uap->fdes]) == NULL ||
	    (fp->f_flag & FREAD) == 0)
		return (EBADF);
	/* 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)
			return (EINVAL);
		MALLOC(iov, struct iovec *, iovlen, M_IOV, M_WAITOK);
		needfree = iov;
	} else {
		iov = aiov;
		needfree = NULL;
	}
	auio.uio_iov = iov;
	auio.uio_iovcnt = uap->iovcnt;
	auio.uio_rw = UIO_READ;
	auio.uio_segflg = UIO_USERSPACE;
	auio.uio_procp = p;
	if (error = copyin((caddr_t)uap->iovp, (caddr_t)iov, iovlen))
		goto done;
	auio.uio_resid = 0;
	for (i = 0; i < uap->iovcnt; i++) {
		if (iov->iov_len < 0) {
			error = EINVAL;
			goto done;
		}
		auio.uio_resid += iov->iov_len;
		if (auio.uio_resid < 0) {
			error = EINVAL;
			goto done;
		}
		iov++;
	}
#ifdef KTRACE
	/*
	 * if tracing, save a copy of iovec
	 */
	if (KTRPOINT(p, KTR_GENIO))  {
		MALLOC(ktriov, struct iovec *, iovlen, M_TEMP, M_WAITOK);
		bcopy((caddr_t)auio.uio_iov, (caddr_t)ktriov, iovlen);
	}
#endif
	cnt = auio.uio_resid;
	if (error = (*fp->f_ops->fo_read)(fp, &auio, fp->f_cred))
		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)
			ktrgenio(p->p_tracep, uap->fdes, UIO_READ, ktriov,
			    cnt, error);
		FREE(ktriov, M_TEMP);
	}
#endif
	*retval = cnt;
done:
	if (needfree)
		FREE(needfree, M_IOV);
	return (error);
}

/*
 * Write system call
 */
struct write_args {
	int	fd;
	char	*buf;
	u_int	nbyte;
};
write(p, uap, retval)
	struct proc *p;
	register struct write_args *uap;
	int *retval;
{
	register struct file *fp;
	register struct filedesc *fdp = p->p_fd;
	struct uio auio;
	struct iovec aiov;
	long cnt, error = 0;
#ifdef KTRACE
	struct iovec ktriov;
#endif

	if (((u_int)uap->fd) >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[uap->fd]) == NULL ||
	    (fp->f_flag & FWRITE) == 0)
		return (EBADF);
	aiov.iov_base = (caddr_t)uap->buf;
	aiov.iov_len = uap->nbyte;
	auio.uio_iov = &aiov;
	auio.uio_iovcnt = 1;
	auio.uio_resid = uap->nbyte;
	auio.uio_rw = UIO_WRITE;
	auio.uio_segflg = UIO_USERSPACE;
	auio.uio_procp = p;
#ifdef KTRACE
	/*
	 * if tracing, save a copy of iovec
	 */
	if (KTRPOINT(p, KTR_GENIO))
		ktriov = aiov;
#endif
	cnt = uap->nbyte;
	if (error = (*fp->f_ops->fo_write)(fp, &auio, fp->f_cred)) {
		if (auio.uio_resid != cnt && (error == ERESTART ||
		    error == EINTR || error == EWOULDBLOCK))
			error = 0;
		if (error == EPIPE)
			psignal(p, SIGPIPE);
	}
	cnt -= auio.uio_resid;
#ifdef KTRACE
	if (KTRPOINT(p, KTR_GENIO) && error == 0)
		ktrgenio(p->p_tracep, uap->fd, UIO_WRITE,
		    &ktriov, cnt, error);
#endif
	*retval = cnt;
	return (error);
}

/*
 * Gather write system call
 */
struct writev_args {
	int	fd;
	struct	iovec *iovp;
	u_int	iovcnt;
};
writev(p, uap, retval)
	struct proc *p;
	register struct writev_args *uap;
	int *retval;
{
	register struct file *fp;
	register struct filedesc *fdp = p->p_fd;
	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;
#endif

	if (((u_int)uap->fd) >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[uap->fd]) == NULL ||
	    (fp->f_flag & FWRITE) == 0)
		return (EBADF);
	/* 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)
			return (EINVAL);
		MALLOC(iov, struct iovec *, iovlen, M_IOV, M_WAITOK);
		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_procp = p;
	if (error = copyin((caddr_t)uap->iovp, (caddr_t)iov, iovlen))
		goto done;
	auio.uio_resid = 0;
	for (i = 0; i < uap->iovcnt; i++) {
		if (iov->iov_len < 0) {
			error = EINVAL;
			goto done;
		}
		auio.uio_resid += iov->iov_len;
		if (auio.uio_resid < 0) {
			error = EINVAL;
			goto done;
		}
		iov++;
	}
#ifdef KTRACE
	/*
	 * if tracing, save a copy of iovec
	 */
	if (KTRPOINT(p, KTR_GENIO))  {
		MALLOC(ktriov, struct iovec *, iovlen, M_TEMP, M_WAITOK);
		bcopy((caddr_t)auio.uio_iov, (caddr_t)ktriov, iovlen);
	}
#endif
	cnt = auio.uio_resid;
	if (error = (*fp->f_ops->fo_write)(fp, &auio, fp->f_cred)) {
		if (auio.uio_resid != cnt && (error == ERESTART ||
		    error == EINTR || error == EWOULDBLOCK))
			error = 0;
		if (error == EPIPE)
			psignal(p, SIGPIPE);
	}
	cnt -= auio.uio_resid;
#ifdef KTRACE
	if (ktriov != NULL) {
		if (error == 0)
			ktrgenio(p->p_tracep, uap->fd, UIO_WRITE,