vfs_syscalls.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 2,115 行 · 第 1/4 页

	vput(vp);
	return (error);
}

/*
 * Set the access and modification times given a file descriptor.
 */
/* ARGSUSED */
int
sys_futimes(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_futimes_args /* {
		syscallarg(int) fd;
		syscallarg(struct timeval *) tptr;
	} */ *uap = v;
	register struct vnode *vp;
	struct timeval tv[2];
	struct vattr vattr;
	int error;
	struct file *fp;

	VATTR_NULL(&vattr);
	if (SCARG(uap, tptr) == NULL) {
		microtime(&tv[0]);
		tv[1] = tv[0];
		vattr.va_vaflags |= VA_UTIMES_NULL;
	} else {
		error = copyin((caddr_t)SCARG(uap, tptr), (caddr_t)tv,
			       sizeof (tv));
		if (error)
			return (error);
	}
	if ((error = getvnode(p->p_fd, SCARG(uap, fd), &fp)) != 0)
		return (error);
	vp = (struct vnode *)fp->f_data;
	VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
	VOP_LOCK(vp);
	if (vp->v_mount->mnt_flag & MNT_RDONLY)
		error = EROFS;
	else {
		vattr.va_atime.tv_sec = tv[0].tv_sec;
		vattr.va_atime.tv_nsec = tv[0].tv_usec * 1000;
		vattr.va_mtime.tv_sec = tv[1].tv_sec;
		vattr.va_mtime.tv_nsec = tv[1].tv_usec * 1000;
		error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
	}
	VOP_UNLOCK(vp);
	return (error);
}

/*
 * Truncate a file given its path name.
 */
/* ARGSUSED */
int
sys_truncate(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_truncate_args /* {
		syscallarg(char *) path;
		syscallarg(int) pad;
		syscallarg(off_t) length;
	} */ *uap = v;
	register struct vnode *vp;
	struct vattr vattr;
	int error;
	struct nameidata nd;

	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
	if ((error = namei(&nd)) != 0)
		return (error);
	vp = nd.ni_vp;
	VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
	VOP_LOCK(vp);
	if (vp->v_type == VDIR)
		error = EISDIR;
	else if ((error = vn_writechk(vp)) == 0 &&
	    (error = VOP_ACCESS(vp, VWRITE, p->p_ucred, p)) == 0) {
		VATTR_NULL(&vattr);
		vattr.va_size = SCARG(uap, length);
		error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
	}
	vput(vp);
	return (error);
}

/*
 * Truncate a file given a file descriptor.
 */
/* ARGSUSED */
int
sys_ftruncate(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_ftruncate_args /* {
		syscallarg(int) fd;
		syscallarg(int) pad;
		syscallarg(off_t) length;
	} */ *uap = v;
	struct vattr vattr;
	struct vnode *vp;
	struct file *fp;
	int error;

	if ((error = getvnode(p->p_fd, SCARG(uap, fd), &fp)) != 0)
		return (error);
	if ((fp->f_flag & FWRITE) == 0)
		return (EINVAL);
	vp = (struct vnode *)fp->f_data;
	VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
	VOP_LOCK(vp);
	if (vp->v_type == VDIR)
		error = EISDIR;
	else if ((error = vn_writechk(vp)) == 0) {
		VATTR_NULL(&vattr);
		vattr.va_size = SCARG(uap, length);
		error = VOP_SETATTR(vp, &vattr, fp->f_cred, p);
	}
	VOP_UNLOCK(vp);
	return (error);
}

/*
 * Sync an open file.
 */
/* ARGSUSED */
int
sys_fsync(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_fsync_args /* {
		syscallarg(int) fd;
	} */ *uap = v;
	register struct vnode *vp;
	struct file *fp;
	int error;

	if ((error = getvnode(p->p_fd, SCARG(uap, fd), &fp)) != 0)
		return (error);
	vp = (struct vnode *)fp->f_data;
	VOP_LOCK(vp);
	error = VOP_FSYNC(vp, fp->f_cred, MNT_WAIT, p);
	VOP_UNLOCK(vp);
	return (error);
}

/*
 * Rename files.  Source and destination must either both be directories,
 * or both not be directories.  If target is a directory, it must be empty.
 */
/* ARGSUSED */
int
sys_rename(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_rename_args /* {
		syscallarg(char *) from;
		syscallarg(char *) to;
	} */ *uap = v;
	register struct vnode *tvp, *fvp, *tdvp;
	struct nameidata fromnd, tond;
	int error;

	NDINIT(&fromnd, DELETE, WANTPARENT | SAVESTART, UIO_USERSPACE,
	    SCARG(uap, from), p);
	if ((error = namei(&fromnd)) != 0)
		return (error);
	fvp = fromnd.ni_vp;
	NDINIT(&tond, RENAME, LOCKPARENT | LOCKLEAF | NOCACHE | SAVESTART,
	    UIO_USERSPACE, SCARG(uap, to), p);
	if ((error = namei(&tond)) != 0) {
		VOP_ABORTOP(fromnd.ni_dvp, &fromnd.ni_cnd);
		vrele(fromnd.ni_dvp);
		vrele(fvp);
		goto out1;
	}
	tdvp = tond.ni_dvp;
	tvp = tond.ni_vp;
	if (tvp != NULL) {
		if (fvp->v_type == VDIR && tvp->v_type != VDIR) {
			error = ENOTDIR;
			goto out;
		} else if (fvp->v_type != VDIR && tvp->v_type == VDIR) {
			error = EISDIR;
			goto out;
		}
	}
	if (fvp == tdvp)
		error = EINVAL;
	/*
	 * If source is the same as the destination (that is the
	 * same inode number with the same name in the same directory),
	 * then there is nothing to do.
	 */
	if (fvp == tvp && fromnd.ni_dvp == tdvp &&
	    fromnd.ni_cnd.cn_namelen == tond.ni_cnd.cn_namelen &&
	    !bcmp(fromnd.ni_cnd.cn_nameptr, tond.ni_cnd.cn_nameptr,
	      fromnd.ni_cnd.cn_namelen))
		error = -1;
out:
	if (!error) {
		VOP_LEASE(tdvp, p, p->p_ucred, LEASE_WRITE);
		if (fromnd.ni_dvp != tdvp)
			VOP_LEASE(fromnd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
		if (tvp)
			VOP_LEASE(tvp, p, p->p_ucred, LEASE_WRITE);
		error = VOP_RENAME(fromnd.ni_dvp, fromnd.ni_vp, &fromnd.ni_cnd,
				   tond.ni_dvp, tond.ni_vp, &tond.ni_cnd);
	} else {
		VOP_ABORTOP(tond.ni_dvp, &tond.ni_cnd);
		if (tdvp == tvp)
			vrele(tdvp);
		else
			vput(tdvp);
		if (tvp)
			vput(tvp);
		VOP_ABORTOP(fromnd.ni_dvp, &fromnd.ni_cnd);
		vrele(fromnd.ni_dvp);
		vrele(fvp);
	}
	vrele(tond.ni_startdir);
	FREE(tond.ni_cnd.cn_pnbuf, M_NAMEI);
out1:
	if (fromnd.ni_startdir)
		vrele(fromnd.ni_startdir);
	FREE(fromnd.ni_cnd.cn_pnbuf, M_NAMEI);
	if (error == -1)
		return (0);
	return (error);
}

/*
 * Make a directory file.
 */
/* ARGSUSED */
int
sys_mkdir(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_mkdir_args /* {
		syscallarg(char *) path;
		syscallarg(int) mode;
	} */ *uap = v;
	register struct vnode *vp;
	struct vattr vattr;
	int error;
	struct nameidata nd;

	NDINIT(&nd, CREATE, LOCKPARENT, UIO_USERSPACE, SCARG(uap, path), p);
	if ((error = namei(&nd)) != 0)
		return (error);
	vp = nd.ni_vp;
	if (vp != NULL) {
		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
		if (nd.ni_dvp == vp)
			vrele(nd.ni_dvp);
		else
			vput(nd.ni_dvp);
		vrele(vp);
		return (EEXIST);
	}
	VATTR_NULL(&vattr);
	vattr.va_type = VDIR;
	vattr.va_mode = (SCARG(uap, mode) & ACCESSPERMS) &~ p->p_fd->fd_cmask;
	VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
	error = VOP_MKDIR(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
	if (!error)
		vput(nd.ni_vp);
	return (error);
}

/*
 * Remove a directory file.
 */
/* ARGSUSED */
int
sys_rmdir(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_rmdir_args /* {
		syscallarg(char *) path;
	} */ *uap = v;
	register struct vnode *vp;
	int error;
	struct nameidata nd;

	NDINIT(&nd, DELETE, LOCKPARENT | LOCKLEAF, UIO_USERSPACE,
	    SCARG(uap, path), p);
	if ((error = namei(&nd)) != 0)
		return (error);
	vp = nd.ni_vp;
	if (vp->v_type != VDIR) {
		error = ENOTDIR;
		goto out;
	}
	/*
	 * No rmdir "." please.
	 */
	if (nd.ni_dvp == vp) {
		error = EINVAL;
		goto out;
	}
	/*
	 * The root of a mounted filesystem cannot be deleted.
	 */
	if (vp->v_flag & VROOT)
		error = EBUSY;
out:
	if (!error) {
		VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
		VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
		error = VOP_RMDIR(nd.ni_dvp, nd.ni_vp, &nd.ni_cnd);
	} else {
		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
		if (nd.ni_dvp == vp)
			vrele(nd.ni_dvp);
		else
			vput(nd.ni_dvp);
		vput(vp);
	}
	return (error);
}

/*
 * Read a block of directory entries in a file system independent format.
 */
int
sys_getdirentries(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_getdirentries_args /* {
		syscallarg(int) fd;
		syscallarg(char *) buf;
		syscallarg(u_int) count;
		syscallarg(long *) basep;
	} */ *uap = v;
	register struct vnode *vp;
	struct file *fp;
	struct uio auio;
	struct iovec aiov;
	long loff;
	int error, eofflag;

	if ((error = getvnode(p->p_fd, SCARG(uap, fd), &fp)) != 0)
		return (error);
	if ((fp->f_flag & FREAD) == 0)
		return (EBADF);
	vp = (struct vnode *)fp->f_data;
unionread:
	if (vp->v_type != VDIR)
		return (EINVAL);
	aiov.iov_base = SCARG(uap, buf);
	aiov.iov_len = SCARG(uap, count);
	auio.uio_iov = &aiov;
	auio.uio_iovcnt = 1;
	auio.uio_rw = UIO_READ;
	auio.uio_segflg = UIO_USERSPACE;
	auio.uio_procp = p;
	auio.uio_resid = SCARG(uap, count);
	VOP_LOCK(vp);
	loff = auio.uio_offset = fp->f_offset;
	error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, (u_long *)0, 0);
	fp->f_offset = auio.uio_offset;
	VOP_UNLOCK(vp);
	if (error)
		return (error);

#ifdef UNION
{
	extern int (**union_vnodeop_p) __P((void *));
	extern struct vnode *union_dircache __P((struct vnode *));

	if ((SCARG(uap, count) == auio.uio_resid) &&
	    (vp->v_op == union_vnodeop_p)) {
		struct vnode *lvp;

		lvp = union_dircache(vp);
		if (lvp != NULLVP) {
			struct vattr va;

			/*
			 * If the directory is opaque,
			 * then don't show lower entries
			 */
			error = VOP_GETATTR(vp, &va, fp->f_cred, p);
			if (va.va_flags & OPAQUE) {
				vput(lvp);
				lvp = NULL;
			}
		}
		
		if (lvp != NULLVP) {
			error = VOP_OPEN(lvp, FREAD, fp->f_cred, p);
			VOP_UNLOCK(lvp);

			if (error) {
				vrele(lvp);
				return (error);
			}
			fp->f_data = (caddr_t) lvp;
			fp->f_offset = 0;
			error = vn_close(vp, FREAD, fp->f_cred, p);
			if (error)
				return (error);
			vp = lvp;
			goto unionread;
		}
	}
}
#endif /* UNION */

	if ((SCARG(uap, count) == auio.uio_resid) &&
	    (vp->v_flag & VROOT) &&
	    (vp->v_mount->mnt_flag & MNT_UNION)) {
		struct vnode *tvp = vp;
		vp = vp->v_mount->mnt_vnodecovered;
		VREF(vp);
		fp->f_data = (caddr_t) vp;
		fp->f_offset = 0;
		vrele(tvp);
		goto unionread;
	}
	error = copyout((caddr_t)&loff, (caddr_t)SCARG(uap, basep),
	    sizeof(long));
	*retval = SCARG(uap, count) - auio.uio_resid;
	return (error);
}

/*
 * Set the mode mask for creation of filesystem nodes.
 */
int
sys_umask(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_umask_args /* {
		syscallarg(int) newmask;
	} */ *uap = v;
	register struct filedesc *fdp;

	fdp = p->p_fd;
	*retval = fdp->fd_cmask;
	fdp->fd_cmask = SCARG(uap, newmask) & ALLPERMS;
	return (0);
}

/*
 * Void all references to file by ripping underlying filesystem
 * away from vnode.
 */
/* ARGSUSED */
int
sys_revoke(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_revoke_args /* {
		syscallarg(char *) path;
	} */ *uap = v;
	register struct vnode *vp;
	struct vattr vattr;
	int error;
	struct nameidata nd;

	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
	if ((error = namei(&nd)) != 0)
		return (error);
	vp = nd.ni_vp;
	if (vp->v_type != VCHR && vp->v_type != VBLK) {
		error = EINVAL;
		goto out;
	}
	if ((error = VOP_GETATTR(vp, &vattr, p->p_ucred, p)) != 0)
		goto out;
	if (p->p_ucred->cr_uid != vattr.va_uid &&
	    (error = suser(p->p_ucred, &p->p_acflag)))
		goto out;
	if (vp->v_usecount > 1 || (vp->v_flag & VALIASED))
		vgoneall(vp);
out:
	vrele(vp);
	return (error);
}

/*
 * Convert a user file descriptor to a kernel file entry.
 */
int
getvnode(fdp, fd, fpp)
	struct filedesc *fdp;
	int fd;
	struct file **fpp;
{
	struct vnode *vp;
	struct file *fp;

	if ((u_int)fd >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[fd]) == NULL)
		return (EBADF);
	if (fp->f_type != DTYPE_VNODE)
		return (EINVAL);
	vp = (struct vnode *)fp->f_data;
	if (vp->v_type == VBAD)
		return (EBADF);
	*fpp = fp;
	return (0);
}