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

	void *v;
	register_t *retval;
{
	register struct sys_fstatfs_args /* {
		syscallarg(int) fd;
		syscallarg(struct statfs *) buf;
	} */ *uap = v;
	struct file *fp;
	struct mount *mp;
	register struct statfs *sp;
	int error;

	if ((error = getvnode(p->p_fd, SCARG(uap, fd), &fp)) != 0)
		return (error);
	mp = ((struct vnode *)fp->f_data)->v_mount;
	sp = &mp->mnt_stat;
	if ((error = VFS_STATFS(mp, sp, p)) != 0)
		return (error);
	sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
	return (copyout((caddr_t)sp, (caddr_t)SCARG(uap, buf), sizeof(*sp)));
}

/*
 * Get statistics on all filesystems.
 */
int
sys_getfsstat(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_getfsstat_args /* {
		syscallarg(struct statfs *) buf;
		syscallarg(long) bufsize;
		syscallarg(int) flags;
	} */ *uap = v;
	register struct mount *mp, *nmp;
	register struct statfs *sp;
	caddr_t sfsp;
	long count, maxcount, error;

	maxcount = SCARG(uap, bufsize) / sizeof(struct statfs);
	sfsp = (caddr_t)SCARG(uap, buf);
	for (count = 0,
	     mp = mountlist.cqh_first; mp != (void *)&mountlist; mp = nmp) {
		nmp = mp->mnt_list.cqe_next;
		if (sfsp && count < maxcount &&
		    ((mp->mnt_flag & MNT_MLOCK) == 0)) {
			sp = &mp->mnt_stat;
			/*
			 * If MNT_NOWAIT is specified, do not refresh the
			 * fsstat cache. MNT_WAIT overrides MNT_NOWAIT.
			 */
			if (((SCARG(uap, flags) & MNT_NOWAIT) == 0 ||
			    (SCARG(uap, flags) & MNT_WAIT)) &&
			    (error = VFS_STATFS(mp, sp, p)))
				continue;
			sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
			error = copyout((caddr_t)sp, sfsp, sizeof(*sp));
			if (error)
				return (error);
			sfsp += sizeof(*sp);
		}
		count++;
	}
	if (sfsp && count > maxcount)
		*retval = maxcount;
	else
		*retval = count;
	return (0);
}

/*
 * Change current working directory to a given file descriptor.
 */
/* ARGSUSED */
int
sys_fchdir(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_fchdir_args /* {
		syscallarg(int) fd;
	} */ *uap = v;
	register struct filedesc *fdp = p->p_fd;
	struct vnode *vp, *tdp;
	struct mount *mp;
	struct file *fp;
	int error;

	if ((error = getvnode(fdp, SCARG(uap, fd), &fp)) != 0)
		return (error);
	vp = (struct vnode *)fp->f_data;
	VREF(vp);
	VOP_LOCK(vp);
	if (vp->v_type != VDIR)
		error = ENOTDIR;
	else
		error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p);
	while (!error && (mp = vp->v_mountedhere) != NULL) {
		if (mp->mnt_flag & MNT_MLOCK) {
			mp->mnt_flag |= MNT_MWAIT;
			sleep((caddr_t)mp, PVFS);
			continue;
		}
		if ((error = VFS_ROOT(mp, &tdp)) != 0)
			break;
		vput(vp);
		vp = tdp;
	}
	VOP_UNLOCK(vp);
	if (error) {
		vrele(vp);
		return (error);
	}
	vrele(fdp->fd_cdir);
	fdp->fd_cdir = vp;
	return (0);
}

/*
 * Change current working directory (``.'').
 */
/* ARGSUSED */
int
sys_chdir(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_chdir_args /* {
		syscallarg(char *) path;
	} */ *uap = v;
	register struct filedesc *fdp = p->p_fd;
	int error;
	struct nameidata nd;

	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
	    SCARG(uap, path), p);
	if ((error = change_dir(&nd, p)) != 0)
		return (error);
	vrele(fdp->fd_cdir);
	fdp->fd_cdir = nd.ni_vp;
	return (0);
}

/*
 * Change notion of root (``/'') directory.
 */
/* ARGSUSED */
int
sys_chroot(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	struct sys_chroot_args /* {
		syscallarg(char *) path;
	} */ *uap = v;
	register struct filedesc *fdp = p->p_fd;
	int error;
	struct nameidata nd;

	if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
		return (error);
	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
	    SCARG(uap, path), p);
	if ((error = change_dir(&nd, p)) != 0)
		return (error);
	if (fdp->fd_rdir != NULL)
		vrele(fdp->fd_rdir);
	fdp->fd_rdir = nd.ni_vp;
	return (0);
}

/*
 * Common routine for chroot and chdir.
 */
static int
change_dir(ndp, p)
	register struct nameidata *ndp;
	struct proc *p;
{
	struct vnode *vp;
	int error;

	if ((error = namei(ndp)) != 0)
		return (error);
	vp = ndp->ni_vp;
	if (vp->v_type != VDIR)
		error = ENOTDIR;
	else
		error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p);
	VOP_UNLOCK(vp);
	if (error)
		vrele(vp);
	return (error);
}

/*
 * Check permissions, allocate an open file structure,
 * and call the device open routine if any.
 */
int
sys_open(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_open_args /* {
		syscallarg(char *) path;
		syscallarg(int) flags;
		syscallarg(int) mode;
	} */ *uap = v;
	register struct filedesc *fdp = p->p_fd;
	register struct file *fp;
	register struct vnode *vp;
	int flags, cmode;
	struct file *nfp;
	int type, indx, error;
	struct flock lf;
	struct nameidata nd;
	extern struct fileops vnops;

	if ((error = falloc(p, &nfp, &indx)) != 0)
		return (error);
	fp = nfp;
	flags = FFLAGS(SCARG(uap, flags));
	cmode = ((SCARG(uap, mode) &~ fdp->fd_cmask) & ALLPERMS) &~ S_ISTXT;
	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
	p->p_dupfd = -indx - 1;			/* XXX check for fdopen */
	if ((error = vn_open(&nd, flags, cmode)) != 0) {
		ffree(fp);
		if ((error == ENODEV || error == ENXIO) &&
		    p->p_dupfd >= 0 &&			/* XXX from fdopen */
		    (error =
			dupfdopen(fdp, indx, p->p_dupfd, flags, error)) == 0) {
			*retval = indx;
			return (0);
		}
		if (error == ERESTART)
			error = EINTR;
		fdp->fd_ofiles[indx] = NULL;
		return (error);
	}
	p->p_dupfd = 0;
	vp = nd.ni_vp;
	fp->f_flag = flags & FMASK;
	fp->f_type = DTYPE_VNODE;
	fp->f_ops = &vnops;
	fp->f_data = (caddr_t)vp;
	if (flags & (O_EXLOCK | O_SHLOCK)) {
		lf.l_whence = SEEK_SET;
		lf.l_start = 0;
		lf.l_len = 0;
		if (flags & O_EXLOCK)
			lf.l_type = F_WRLCK;
		else
			lf.l_type = F_RDLCK;
		type = F_FLOCK;
		if ((flags & FNONBLOCK) == 0)
			type |= F_WAIT;
		VOP_UNLOCK(vp);
		error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type);
		if (error) {
			(void) vn_close(vp, fp->f_flag, fp->f_cred, p);
			ffree(fp);
			fdp->fd_ofiles[indx] = NULL;
			return (error);
		}
		VOP_LOCK(vp);
		fp->f_flag |= FHASLOCK;
	}
	VOP_UNLOCK(vp);
	*retval = indx;
	return (0);
}

/*
 * Create a special file.
 */
/* ARGSUSED */
int
sys_mknod(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_mknod_args /* {
		syscallarg(char *) path;
		syscallarg(int) mode;
		syscallarg(int) dev;
	} */ *uap = v;
	register struct vnode *vp;
	struct vattr vattr;
	int error;
	int whiteout = 0;
	struct nameidata nd;

	if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
		return (error);
	NDINIT(&nd, CREATE, LOCKPARENT, UIO_USERSPACE, SCARG(uap, path), p);
	if ((error = namei(&nd)) != 0)
		return (error);
	vp = nd.ni_vp;
	if (vp != NULL)
		error = EEXIST;
	else {
		VATTR_NULL(&vattr);
		vattr.va_mode = (SCARG(uap, mode) & ALLPERMS) &~ p->p_fd->fd_cmask;
		vattr.va_rdev = SCARG(uap, dev);
		whiteout = 0;

		switch (SCARG(uap, mode) & S_IFMT) {
		case S_IFMT:	/* used by badsect to flag bad sectors */
			vattr.va_type = VBAD;
			break;
		case S_IFCHR:
			vattr.va_type = VCHR;
			break;
		case S_IFBLK:
			vattr.va_type = VBLK;
			break;
		case S_IFWHT:
			whiteout = 1;
			break;
		default:
			error = EINVAL;
			break;
		}
	}
	if (!error) {
		VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
		if (whiteout) {
			error = VOP_WHITEOUT(nd.ni_dvp, &nd.ni_cnd, CREATE);
			if (error)
				VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
			vput(nd.ni_dvp);
		} else {
			error = VOP_MKNOD(nd.ni_dvp, &nd.ni_vp,
						&nd.ni_cnd, &vattr);
		}
	} else {
		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
		if (nd.ni_dvp == vp)
			vrele(nd.ni_dvp);
		else
			vput(nd.ni_dvp);
		if (vp)
			vrele(vp);
	}
	return (error);
}

/*
 * Create a named pipe.
 */
/* ARGSUSED */
int
sys_mkfifo(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
#ifndef FIFO
	return (EOPNOTSUPP);
#else
	register struct sys_mkfifo_args /* {
		syscallarg(char *) path;
		syscallarg(int) mode;
	} */ *uap = v;
	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);
	if (nd.ni_vp != NULL) {
		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
		if (nd.ni_dvp == nd.ni_vp)
			vrele(nd.ni_dvp);
		else
			vput(nd.ni_dvp);
		vrele(nd.ni_vp);
		return (EEXIST);
	}
	VATTR_NULL(&vattr);
	vattr.va_type = VFIFO;
	vattr.va_mode = (SCARG(uap, mode) & ALLPERMS) &~ p->p_fd->fd_cmask;
	VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
	return (VOP_MKNOD(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr));
#endif /* FIFO */
}

/*
 * Make a hard file link.
 */
/* ARGSUSED */
int
sys_link(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_link_args /* {
		syscallarg(char *) path;
		syscallarg(char *) link;
	} */ *uap = v;
	register struct vnode *vp;
	struct nameidata nd;
	int error;

	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
	if ((error = namei(&nd)) != 0)
		return (error);
	vp = nd.ni_vp;
	NDINIT(&nd, CREATE, LOCKPARENT, UIO_USERSPACE, SCARG(uap, link), p);
	if ((error = namei(&nd)) != 0)
		goto out;
	if (nd.ni_vp) {
		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
		if (nd.ni_dvp == nd.ni_vp)
			vrele(nd.ni_dvp);
		else
			vput(nd.ni_dvp);
		vrele(nd.ni_vp);
		error = EEXIST;
		goto out;
	}
	VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
	VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
	error = VOP_LINK(nd.ni_dvp, vp, &nd.ni_cnd);
out:
	vrele(vp);
	return (error);
}

/*
 * Make a symbolic link.
 */
/* ARGSUSED */
int
sys_symlink(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_symlink_args /* {
		syscallarg(char *) path;
		syscallarg(char *) link;
	} */ *uap = v;
	struct vattr vattr;
	char *path;
	int error;
	struct nameidata nd;

	MALLOC(path, char *, MAXPATHLEN, M_NAMEI, M_WAITOK);
	error = copyinstr(SCARG(uap, path), path, MAXPATHLEN, NULL);
	if (error)
		goto out;
	NDINIT(&nd, CREATE, LOCKPARENT, UIO_USERSPACE, SCARG(uap, link), p);
	if ((error = namei(&nd)) != 0)
		goto out;
	if (nd.ni_vp) {
		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
		if (nd.ni_dvp == nd.ni_vp)
			vrele(nd.ni_dvp);
		else
			vput(nd.ni_dvp);
		vrele(nd.ni_vp);
		error = EEXIST;
		goto out;
	}
	VATTR_NULL(&vattr);
	vattr.va_mode = ACCESSPERMS &~ p->p_fd->fd_cmask;
	VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
	error = VOP_SYMLINK(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr, path);
out:
	FREE(path, M_NAMEI);
	return (error);
}

/*
 * Delete a whiteout from the filesystem.
 */
/* ARGSUSED */
int
sys_undelete(p, v, retval)
	struct proc *p;
	void *v;
	register_t *retval;
{
	register struct sys_undelete_args /* {
		syscallarg(char *) path;
	} */ *uap = v;
	int error;
	struct nameidata nd;

	NDINIT(&nd, DELETE, LOCKPARENT|DOWHITEOUT, UIO_USERSPACE,
	    SCARG(uap, path), p);
	error = namei(&nd);
	if (error)
		return (error);

	if (nd.ni_vp != NULLVP || !(nd.ni_cnd.cn_flags & ISWHITEOUT)) {
		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
		if (nd.ni_dvp == nd.ni_vp)
			vrele(nd.ni_dvp);
		else
			vput(nd.ni_dvp);
		if (nd.ni_vp)
			vrele(nd.ni_vp);
		return (EEXIST);
	}

	VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
	if ((error = VOP_WHITEOUT(nd.ni_dvp, &nd.ni_cnd, DELETE)) != 0)
		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
	vput(nd.ni_dvp);
	return (error);
}

/*
 * Delete a name from the filesystem.
 */
/* ARGSUSED */
int