kern_descrip.c

来自「基于组件方式开发操作系统的OSKIT源代码」· C语言 代码 · 共 925 行 · 第 1/2 页

/*	$NetBSD: kern_descrip.c,v 1.42 1996/03/30 22:24:38 christos Exp $	*/

/*
 * Copyright (c) 1982, 1986, 1989, 1991, 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.
 *
 *	@(#)kern_descrip.c	8.6 (Berkeley) 4/19/94
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/fcntl.h>
#include <sys/malloc.h>
#include <sys/syslog.h>
#include <sys/unistd.h>
#include <sys/resourcevar.h>
#include <sys/conf.h>

#include <sys/mount.h>
#include <sys/syscallargs.h>

#include <vm/vm.h>

/*
 * Descriptor management.
 */
struct filelist filehead;	/* head of list of open files */
int nfiles;			/* actual number of open files */

static __inline void fd_used __P((struct filedesc *, int));
static __inline void fd_unused __P((struct filedesc *, int));
int finishdup __P((struct filedesc *, int, int, register_t *));

static __inline void
fd_used(fdp, fd)
	register struct filedesc *fdp;
	register int fd;
{

	if (fd > fdp->fd_lastfile)
		fdp->fd_lastfile = fd;
}

static __inline void
fd_unused(fdp, fd)
	register struct filedesc *fdp;
	register int fd;
{

	if (fd < fdp->fd_freefile)
		fdp->fd_freefile = fd;
#ifdef DIAGNOSTIC
	if (fd > fdp->fd_lastfile)
		panic("fd_unused: fd_lastfile inconsistent");
#endif
	if (fd == fdp->fd_lastfile) {
		do {
			fd--;
		} while (fd >= 0 && fdp->fd_ofiles[fd] == NULL);
		fdp->fd_lastfile = fd;
	}
}

/*
 * System calls on descriptors.
 */

/*
 * Duplicate a file descriptor.
 */
/* ARGSUSED */
int
sys_dup(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_dup_args /* {
		syscallarg(u_int) fd;
	} */ *uap = v;
	register struct filedesc *fdp = p->p_fd;
	register int old = SCARG(uap, fd);
	int new;
	int error;

	if ((u_int)old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL)
		return (EBADF);
	if ((error = fdalloc(p, 0, &new)) != 0)
		return (error);
	return (finishdup(fdp, old, new, retval));
}

/*
 * Duplicate a file descriptor to a particular value.
 */
/* ARGSUSED */
int
sys_dup2(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_dup2_args /* {
		syscallarg(u_int) from;
		syscallarg(u_int) to;
	} */ *uap = v;
	register struct filedesc *fdp = p->p_fd;
	register int old = SCARG(uap, from), new = SCARG(uap, to);
	int i, error;

	if ((u_int)old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL ||
	    (u_int)new >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
	    (u_int)new >= maxfiles)
		return (EBADF);
	if (old == new) {
		*retval = new;
		return (0);
	}
	if (new >= fdp->fd_nfiles) {
		if ((error = fdalloc(p, new, &i)) != 0)
			return (error);
		if (new != i)
			panic("dup2: fdalloc");
	} else {
		(void) fdrelease(p, new);
	}
	return (finishdup(fdp, old, new, retval));
}

/*
 * The file control system call.
 */
/* ARGSUSED */
int
sys_fcntl(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_fcntl_args /* {
		syscallarg(int) fd;
		syscallarg(int) cmd;
		syscallarg(void *) arg;
	} */ *uap = v;
	int fd = SCARG(uap, fd);
	register struct filedesc *fdp = p->p_fd;
	register struct file *fp;
	struct vnode *vp;
	int i, tmp, error, flg = F_POSIX;
	struct flock fl;
	int newmin;

	if ((u_int)fd >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[fd]) == NULL)
		return (EBADF);
	switch (SCARG(uap, cmd)) {

	case F_DUPFD:
		newmin = (long)SCARG(uap, arg);
		if ((u_int)newmin >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
		    (u_int)newmin >= maxfiles)
			return (EINVAL);
		if ((error = fdalloc(p, newmin, &i)) != 0)
			return (error);
		return (finishdup(fdp, fd, i, retval));

	case F_GETFD:
		*retval = fdp->fd_ofileflags[fd] & UF_EXCLOSE ? 1 : 0;
		return (0);

	case F_SETFD:
		if ((long)SCARG(uap, arg) & 1)
			fdp->fd_ofileflags[fd] |= UF_EXCLOSE;
		else
			fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE;
		return (0);

	case F_GETFL:
		*retval = OFLAGS(fp->f_flag);
		return (0);

	case F_SETFL:
		fp->f_flag &= ~FCNTLFLAGS;
		fp->f_flag |= FFLAGS((long)SCARG(uap, arg)) & FCNTLFLAGS;
		tmp = fp->f_flag & FNONBLOCK;
		error = (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p);
		if (error)
			return (error);
		tmp = fp->f_flag & FASYNC;
		error = (*fp->f_ops->fo_ioctl)(fp, FIOASYNC, (caddr_t)&tmp, p);
		if (!error)
			return (0);
		fp->f_flag &= ~FNONBLOCK;
		tmp = 0;
		(void) (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p);
		return (error);

	case F_GETOWN:
		if (fp->f_type == DTYPE_SOCKET) {
			*retval = ((struct socket *)fp->f_data)->so_pgid;
			return (0);
		}
		error = (*fp->f_ops->fo_ioctl)
			(fp, TIOCGPGRP, (caddr_t)retval, p);
		*retval = -*retval;
		return (error);

	case F_SETOWN:
		if (fp->f_type == DTYPE_SOCKET) {
			((struct socket *)fp->f_data)->so_pgid =
			    (long)SCARG(uap, arg);
			return (0);
		}
		if ((long)SCARG(uap, arg) <= 0) {
			SCARG(uap, arg) = (void *)(-(long)SCARG(uap, arg));
		} else {
			struct proc *p1 = pfind((long)SCARG(uap, arg));
			if (p1 == 0)
				return (ESRCH);
			SCARG(uap, arg) = (void *)(long)p1->p_pgrp->pg_id;
		}
		return ((*fp->f_ops->fo_ioctl)
			(fp, TIOCSPGRP, (caddr_t)&SCARG(uap, arg), p));

	case F_SETLKW:
		flg |= F_WAIT;
		/* Fall into F_SETLK */

	case F_SETLK:
		if (fp->f_type != DTYPE_VNODE)
			return (EBADF);
		vp = (struct vnode *)fp->f_data;
		/* Copy in the lock structure */
		error = copyin((caddr_t)SCARG(uap, arg), (caddr_t)&fl,
		    sizeof (fl));
		if (error)
			return (error);
		if (fl.l_whence == SEEK_CUR)
			fl.l_start += fp->f_offset;
		switch (fl.l_type) {

		case F_RDLCK:
			if ((fp->f_flag & FREAD) == 0)
				return (EBADF);
			p->p_flag |= P_ADVLOCK;
			return (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &fl, flg));

		case F_WRLCK:
			if ((fp->f_flag & FWRITE) == 0)
				return (EBADF);
			p->p_flag |= P_ADVLOCK;
			return (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &fl, flg));

		case F_UNLCK:
			return (VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &fl,
				F_POSIX));

		default:
			return (EINVAL);
		}

	case F_GETLK:
		if (fp->f_type != DTYPE_VNODE)
			return (EBADF);
		vp = (struct vnode *)fp->f_data;
		/* Copy in the lock structure */
		error = copyin((caddr_t)SCARG(uap, arg), (caddr_t)&fl,
		    sizeof (fl));
		if (error)
			return (error);
		if (fl.l_whence == SEEK_CUR)
			fl.l_start += fp->f_offset;
		error = VOP_ADVLOCK(vp, (caddr_t)p, F_GETLK, &fl, F_POSIX);
		if (error)
			return (error);
		return (copyout((caddr_t)&fl, (caddr_t)SCARG(uap, arg),
		    sizeof (fl)));

	default:
		return (EINVAL);
	}
	/* NOTREACHED */
}

/*
 * Common code for dup, dup2, and fcntl(F_DUPFD).
 */
int
finishdup(fdp, old, new, retval)
	register struct filedesc *fdp;
	register int old, new;
	register_t *retval;
{
	register struct file *fp;

	fp = fdp->fd_ofiles[old];
	fdp->fd_ofiles[new] = fp;
	fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE;
	fp->f_count++;
	fd_used(fdp, new);
	*retval = new;
	return (0);
}

int
fdrelease(p, fd)
	struct proc *p;
	int fd;
{
	register struct filedesc *fdp = p->p_fd;
	register struct file **fpp, *fp;
	register char *pf;

	fpp = &fdp->fd_ofiles[fd];
	fp = *fpp;
	if (fp == NULL)
		return (EBADF);
	pf = &fdp->fd_ofileflags[fd];
	if (*pf & UF_MAPPED)
		(void) munmapfd(p, fd);
	*fpp = NULL;
	*pf = 0;
	fd_unused(fdp, fd);
	return (closef(fp, p));
}

/*
 * Close a file descriptor.
 */
/* ARGSUSED */
int
sys_close(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_close_args /* {
		syscallarg(int) fd;
	} */ *uap = v;
	int fd = SCARG(uap, fd);
	register struct filedesc *fdp = p->p_fd;

	if ((u_int)fd >= fdp->fd_nfiles)
		return (EBADF);
	return (fdrelease(p, fd));
}

/*
 * Return status information about a file descriptor.
 */
/* ARGSUSED */
int
sys_fstat(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_fstat_args /* {
		syscallarg(int) fd;
		syscallarg(struct stat *) sb;
	} */ *uap = v;
	int fd = SCARG(uap, fd);
	register struct filedesc *fdp = p->p_fd;
	register struct file *fp;
	struct stat ub;
	int error;

	if ((u_int)fd >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[fd]) == NULL)
		return (EBADF);
	switch (fp->f_type) {

	case DTYPE_VNODE:
		error = vn_stat((struct vnode *)fp->f_data, &ub, p);
		break;

	case DTYPE_SOCKET:
		error = soo_stat((struct socket *)fp->f_data, &ub);
		break;

	default:
		panic("fstat");
		/*NOTREACHED*/
	}
	if (error == 0)
		error = copyout((caddr_t)&ub, (caddr_t)SCARG(uap, sb),
		    sizeof (ub));
	return (error);
}

/*
 * Return pathconf information about a file descriptor.
 */
/* ARGSUSED */
int
sys_fpathconf(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_fpathconf_args /* {
		syscallarg(int) fd;
		syscallarg(int) name;
	} */ *uap = v;
	int fd = SCARG(uap, fd);
	struct filedesc *fdp = p->p_fd;
	struct file *fp;
	struct vnode *vp;

	if ((u_int)fd >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[fd]) == NULL)
		return (EBADF);
	switch (fp->f_type) {

	case DTYPE_SOCKET:
		if (SCARG(uap, name) != _PC_PIPE_BUF)
			return (EINVAL);
		*retval = PIPE_BUF;
		return (0);

	case DTYPE_VNODE: