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

sys_unlink(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_unlink_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;

	/*
	 * The root of a mounted filesystem cannot be deleted.
	 */
	if (vp->v_flag & VROOT) {
		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
		if (nd.ni_dvp == vp)
			vrele(nd.ni_dvp);
		else
			vput(nd.ni_dvp);
		vput(vp);
		error = EBUSY;
		goto out;
	}

	(void)vnode_pager_uncache(vp);

	VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
	VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
	error = VOP_REMOVE(nd.ni_dvp, nd.ni_vp, &nd.ni_cnd);
out:
	return (error);
}

/*
 * Reposition read/write file offset.
 */
int
sys_lseek(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_lseek_args /* {
		syscallarg(int) fd;
		syscallarg(int) pad;
		syscallarg(off_t) offset;
		syscallarg(int) whence;
	} */ *uap = v;
	struct ucred *cred = p->p_ucred;
	register struct filedesc *fdp = p->p_fd;
	register struct file *fp;
	struct vattr vattr;
	int error;

	if ((u_int)SCARG(uap, fd) >= fdp->fd_nfiles ||
	    (fp = fdp->fd_ofiles[SCARG(uap, fd)]) == NULL)
		return (EBADF);
	if (fp->f_type != DTYPE_VNODE)
		return (ESPIPE);
	switch (SCARG(uap, whence)) {
	case L_INCR:
		fp->f_offset += SCARG(uap, offset);
		break;
	case L_XTND:
		error = VOP_GETATTR((struct vnode *)fp->f_data, &vattr,
				    cred, p);
		if (error)
			return (error);
		fp->f_offset = SCARG(uap, offset) + vattr.va_size;
		break;
	case L_SET:
		fp->f_offset = SCARG(uap, offset);
		break;
	default:
		return (EINVAL);
	}
	*(off_t *)retval = fp->f_offset;
	return (0);
}

/*
 * Check access permissions.
 */
int
sys_access(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_access_args /* {
		syscallarg(char *) path;
		syscallarg(int) flags;
	} */ *uap = v;
	register struct ucred *cred = p->p_ucred;
	register struct vnode *vp;
	int error, flags, t_gid, t_uid;
	struct nameidata nd;

	t_uid = cred->cr_uid;
	t_gid = cred->cr_gid;
	cred->cr_uid = p->p_cred->p_ruid;
	cred->cr_gid = p->p_cred->p_rgid;
	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
	    SCARG(uap, path), p);
	if ((error = namei(&nd)) != 0)
		goto out1;
	vp = nd.ni_vp;

	/* Flags == 0 means only check for existence. */
	if (SCARG(uap, flags)) {
		flags = 0;
		if (SCARG(uap, flags) & R_OK)
			flags |= VREAD;
		if (SCARG(uap, flags) & W_OK)
			flags |= VWRITE;
		if (SCARG(uap, flags) & X_OK)
			flags |= VEXEC;
		if ((flags & VWRITE) == 0 || (error = vn_writechk(vp)) == 0)
			error = VOP_ACCESS(vp, flags, cred, p);
	}
	vput(vp);
out1:
	cred->cr_uid = t_uid;
	cred->cr_gid = t_gid;
	return (error);
}

/*
 * Get file status; this version follows links.
 */
/* ARGSUSED */
int
sys_stat(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_stat_args /* {
		syscallarg(char *) path;
		syscallarg(struct stat *) ub;
	} */ *uap = v;
	struct stat sb;
	int error;
	struct nameidata nd;

	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
	    SCARG(uap, path), p);
	if ((error = namei(&nd)) != 0)
		return (error);
	error = vn_stat(nd.ni_vp, &sb, p);
	vput(nd.ni_vp);
	if (error)
		return (error);
	error = copyout((caddr_t)&sb, (caddr_t)SCARG(uap, ub), sizeof (sb));
	return (error);
}

/*
 * Get file status; this version does not follow links.
 */
/* ARGSUSED */
int
sys_lstat(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_lstat_args /* {
		syscallarg(char *) path;
		syscallarg(struct stat *) ub;
	} */ *uap = v;
	struct stat sb;
	int error;
	struct nameidata nd;

	NDINIT(&nd, LOOKUP, NOFOLLOW | LOCKLEAF, UIO_USERSPACE,
	    SCARG(uap, path), p);
	if ((error = namei(&nd)) != 0)
		return (error);
	error = vn_stat(nd.ni_vp, &sb, p);
	vput(nd.ni_vp);
	if (error)
		return (error);
	error = copyout((caddr_t)&sb, (caddr_t)SCARG(uap, ub), sizeof (sb));
	return (error);
}

/*
 * Get configurable pathname variables.
 */
/* ARGSUSED */
int
sys_pathconf(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_pathconf_args /* {
		syscallarg(char *) path;
		syscallarg(int) name;
	} */ *uap = v;
	int error;
	struct nameidata nd;

	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
	    SCARG(uap, path), p);
	if ((error = namei(&nd)) != 0)
		return (error);
	error = VOP_PATHCONF(nd.ni_vp, SCARG(uap, name), retval);
	vput(nd.ni_vp);
	return (error);
}

/*
 * Return target name of a symbolic link.
 */
/* ARGSUSED */
int
sys_readlink(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_readlink_args /* {
		syscallarg(char *) path;
		syscallarg(char *) buf;
		syscallarg(int) count;
	} */ *uap = v;
	register struct vnode *vp;
	struct iovec aiov;
	struct uio auio;
	int error;
	struct nameidata nd;

	NDINIT(&nd, LOOKUP, NOFOLLOW | LOCKLEAF, UIO_USERSPACE,
	    SCARG(uap, path), p);
	if ((error = namei(&nd)) != 0)
		return (error);
	vp = nd.ni_vp;
	if (vp->v_type != VLNK)
		error = EINVAL;
	else {
		aiov.iov_base = SCARG(uap, buf);
		aiov.iov_len = SCARG(uap, count);
		auio.uio_iov = &aiov;
		auio.uio_iovcnt = 1;
		auio.uio_offset = 0;
		auio.uio_rw = UIO_READ;
		auio.uio_segflg = UIO_USERSPACE;
		auio.uio_procp = p;
		auio.uio_resid = SCARG(uap, count);
		error = VOP_READLINK(vp, &auio, p->p_ucred);
	}
	vput(vp);
	*retval = SCARG(uap, count) - auio.uio_resid;
	return (error);
}

/*
 * Change flags of a file given a path name.
 */
/* ARGSUSED */
int
sys_chflags(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_chflags_args /* {
		syscallarg(char *) path;
		syscallarg(int) flags;
	} */ *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_mount->mnt_flag & MNT_RDONLY)
		error = EROFS;
	else {
		VATTR_NULL(&vattr);
		vattr.va_flags = SCARG(uap, flags);
		error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
	}
	vput(vp);
	return (error);
}

/*
 * Change flags of a file given a file descriptor.
 */
/* ARGSUSED */
int
sys_fchflags(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_fchflags_args /* {
		syscallarg(int) fd;
		syscallarg(int) flags;
	} */ *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);
	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_NULL(&vattr);
		vattr.va_flags = SCARG(uap, flags);
		error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
	}
	VOP_UNLOCK(vp);
	return (error);
}

/*
 * Change mode of a file given path name.
 */
/* ARGSUSED */
int
sys_chmod(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_chmod_args /* {
		syscallarg(char *) path;
		syscallarg(int) mode;
	} */ *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_mount->mnt_flag & MNT_RDONLY)
		error = EROFS;
	else {
		VATTR_NULL(&vattr);
		vattr.va_mode = SCARG(uap, mode) & ALLPERMS;
		error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
	}
	vput(vp);
	return (error);
}

/*
 * Change mode of a file given a file descriptor.
 */
/* ARGSUSED */
int
sys_fchmod(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_fchmod_args /* {
		syscallarg(int) fd;
		syscallarg(int) mode;
	} */ *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);
	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_NULL(&vattr);
		vattr.va_mode = SCARG(uap, mode) & ALLPERMS;
		error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
	}
	VOP_UNLOCK(vp);
	return (error);
}

/*
 * Set ownership given a path name.
 */
/* ARGSUSED */
int
sys_chown(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_chown_args /* {
		syscallarg(char *) path;
		syscallarg(int) uid;
		syscallarg(int) gid;
	} */ *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_mount->mnt_flag & MNT_RDONLY)
		error = EROFS;
	else {
		VATTR_NULL(&vattr);
		vattr.va_uid = SCARG(uap, uid);
		vattr.va_gid = SCARG(uap, gid);
		error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
	}
	vput(vp);
	return (error);
}

/*
 * Set ownership given a file descriptor.
 */
/* ARGSUSED */
int
sys_fchown(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_fchown_args /* {
		syscallarg(int) fd;
		syscallarg(int) uid;
		syscallarg(int) gid;
	} */ *uap = v;
	register struct vnode *vp;
	struct vattr vattr;
	int error;
	struct file *fp;

	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_NULL(&vattr);
		vattr.va_uid = SCARG(uap, uid);
		vattr.va_gid = SCARG(uap, gid);
		error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
	}
	VOP_UNLOCK(vp);
	return (error);
}

/*
 * Set the access and modification times given a path name.
 */
/* ARGSUSED */
int
sys_utimes(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_utimes_args /* {
		syscallarg(char *) path;
		syscallarg(struct timeval *) tptr;
	} */ *uap = v;
	register struct vnode *vp;
	struct timeval tv[2];
	struct vattr vattr;
	int error;
	struct nameidata nd;

	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);
	}
	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_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);
	}