kern_descrip.c

早期freebsd实现

/*
 * 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>

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

/*
 * System calls on descriptors.
 */
struct getdtablesize_args {
	int	dummy;
};
/* ARGSUSED */
getdtablesize(p, uap, retval)
	struct proc *p;
	struct getdtablesize_args *uap;
	int *retval;
{

	*retval = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles);
	return (0);
}

/*
 * Duplicate a file descriptor.
 */
struct dup_args {
	u_int	fd;
};
/* ARGSUSED */
dup(p, uap, retval)
	struct proc *p;
	struct dup_args *uap;
	int *retval;
{
	register struct filedesc *fdp;
	u_int old;
	int new, error;

	old = uap->fd;
	/*
	 * XXX Compatibility
	 */
	if (old &~ 077) { uap->fd &= 077; return (dup2(p, uap, retval)); }

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

/*
 * Duplicate a file descriptor to a particular value.
 */
struct dup2_args {
	u_int	from;
	u_int	to;
};
/* ARGSUSED */
dup2(p, uap, retval)
	struct proc *p;
	struct dup2_args *uap;
	int *retval;
{
	register struct filedesc *fdp = p->p_fd;
	register u_int old = uap->from, new = uap->to;
	int i, error;

	if (old >= fdp->fd_nfiles ||
	    fdp->fd_ofiles[old] == NULL ||
	    new >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
	    new >= maxfiles)
		return (EBADF);
	if (old == new) {
		*retval = new;
		return (0);
	}
	if (new >= fdp->fd_nfiles) {
		if (error = fdalloc(p, new, &i))
			return (error);
		if (new != i)
			panic("dup2: fdalloc");
	} else if (fdp->fd_ofiles[new]) {
		if (fdp->fd_ofileflags[new] & UF_MAPPED)
			(void) munmapfd(p, new);
		/*
		 * dup2() must succeed even if the close has an error.
		 */
		(void) closef(fdp->fd_ofiles[new], p);
	}
	return (finishdup(fdp, (int)old, (int)new, retval));
}

/*
 * The file control system call.
 */
struct fcntl_args {
	int	fd;
	int	cmd;
	int	arg;
};
/* ARGSUSED */
fcntl(p, uap, retval)
	struct proc *p;
	register struct fcntl_args *uap;
	int *retval;
{
	register struct filedesc *fdp = p->p_fd;
	register struct file *fp;
	register char *pop;
	struct vnode *vp;
	int i, tmp, error, flg = F_POSIX;
	struct flock fl;
	u_int newmin;

	if ((unsigned)uap->fd >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[uap->fd]) == NULL)
		return (EBADF);
	pop = &fdp->fd_ofileflags[uap->fd];
	switch (uap->cmd) {

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

	case F_GETFD:
		*retval = *pop & 1;
		return (0);

	case F_SETFD:
		*pop = (*pop &~ 1) | (uap->arg & 1);
		return (0);

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

	case F_SETFL:
		fp->f_flag &= ~FCNTLFLAGS;
		fp->f_flag |= FFLAGS(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, (int)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 = uap->arg;
			return (0);
		}
		if (uap->arg <= 0) {
			uap->arg = -uap->arg;
		} else {
			struct proc *p1 = pfind(uap->arg);
			if (p1 == 0)
				return (ESRCH);
			uap->arg = p1->p_pgrp->pg_id;
		}
		return ((*fp->f_ops->fo_ioctl)
			(fp, (int)TIOCSPGRP, (caddr_t)&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)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)uap->arg, (caddr_t)&fl, sizeof (fl));
		if (error)
			return (error);
		if (fl.l_whence == SEEK_CUR)
			fl.l_start += fp->f_offset;
		if (error = VOP_ADVLOCK(vp, (caddr_t)p, F_GETLK, &fl, F_POSIX))
			return (error);
		return (copyout((caddr_t)&fl, (caddr_t)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, *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++;
	if (new > fdp->fd_lastfile)
		fdp->fd_lastfile = new;
	*retval = new;
	return (0);
}

/*
 * Close a file descriptor.
 */
struct close_args {
	int	fd;
};
/* ARGSUSED */
close(p, uap, retval)
	struct proc *p;
	struct close_args *uap;
	int *retval;
{
	register struct filedesc *fdp = p->p_fd;
	register struct file *fp;
	register int fd = uap->fd;
	register u_char *pf;

	if ((unsigned)fd >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[fd]) == NULL)
		return (EBADF);
	pf = (u_char *)&fdp->fd_ofileflags[fd];
	if (*pf & UF_MAPPED)
		(void) munmapfd(p, fd);
	fdp->fd_ofiles[fd] = NULL;
	while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
		fdp->fd_lastfile--;
	if (fd < fdp->fd_freefile)
		fdp->fd_freefile = fd;
	*pf = 0;
	return (closef(fp, p));
}

#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
/*
 * Return status information about a file descriptor.
 */
struct ofstat_args {
	int	fd;
	struct	ostat *sb;
};
/* ARGSUSED */
ofstat(p, uap, retval)
	struct proc *p;
	register struct ofstat_args *uap;
	int *retval;
{
	register struct filedesc *fdp = p->p_fd;
	register struct file *fp;
	struct stat ub;
	struct ostat oub;
	int error;

	if ((unsigned)uap->fd >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[uap->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("ofstat");
		/*NOTREACHED*/
	}
	cvtstat(&ub, &oub);
	if (error == 0)
		error = copyout((caddr_t)&oub, (caddr_t)uap->sb, sizeof (oub));
	return (error);
}
#endif /* COMPAT_43 || COMPAT_SUNOS */

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

	if ((unsigned)uap->fd >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[uap->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)uap->sb, sizeof (ub));
	return (error);
}

/*
 * Return pathconf information about a file descriptor.
 */
struct fpathconf_args {
	int	fd;
	int	name;
};
/* ARGSUSED */
fpathconf(p, uap, retval)
	struct proc *p;
	register struct fpathconf_args *uap;
	int *retval;
{
	struct filedesc *fdp = p->p_fd;
	struct file *fp;
	struct vnode *vp;

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

	case DTYPE_SOCKET: