nfs_serv.c

早期freebsd实现

	/*
	 * Check for degenerate cases of nothing useful read.
	 * If so go try again
	 */
	cpos = rbuf + on;
	cend = rbuf + siz;
	dp = (struct dirent *)cpos;
	while (cpos < cend && dp->d_fileno == 0) {
		cpos += dp->d_reclen;
		dp = (struct dirent *)cpos;
	}
	if (cpos >= cend) {
		toff = off;
		siz = fullsiz;
		on = 0;
		goto again;
	}

	cpos = rbuf + on;
	cend = rbuf + siz;
	dp = (struct dirent *)cpos;
	len = 3*NFSX_UNSIGNED;	/* paranoia, probably can be 0 */
	nfsm_reply(siz);
	mp = mp2 = mb;
	bp = bpos;
	be = bp + M_TRAILINGSPACE(mp);

	/* Loop through the records and build reply */
	while (cpos < cend) {
		if (dp->d_fileno != 0) {
			nlen = dp->d_namlen;
			rem = nfsm_rndup(nlen)-nlen;
			len += (4*NFSX_UNSIGNED + nlen + rem);
			if (len > cnt) {
				eofflag = 0;
				break;
			}
			/*
			 * Build the directory record xdr from
			 * the dirent entry.
			 */
			nfsm_clget;
			*tl = nfs_true;
			bp += NFSX_UNSIGNED;
			nfsm_clget;
			*tl = txdr_unsigned(dp->d_fileno);
			bp += NFSX_UNSIGNED;
			nfsm_clget;
			*tl = txdr_unsigned(nlen);
			bp += NFSX_UNSIGNED;
	
			/* And loop around copying the name */
			xfer = nlen;
			cp = dp->d_name;
			while (xfer > 0) {
				nfsm_clget;
				if ((bp+xfer) > be)
					tsiz = be-bp;
				else
					tsiz = xfer;
				bcopy(cp, bp, tsiz);
				bp += tsiz;
				xfer -= tsiz;
				if (xfer > 0)
					cp += tsiz;
			}
			/* And null pad to a long boundary */
			for (i = 0; i < rem; i++)
				*bp++ = '\0';
			nfsm_clget;
	
			/* Finish off the record */
			toff += dp->d_reclen;
			*tl = txdr_unsigned(toff);
			bp += NFSX_UNSIGNED;
		} else
			toff += dp->d_reclen;
		cpos += dp->d_reclen;
		dp = (struct dirent *)cpos;
	}
	vrele(vp);
	nfsm_clget;
	*tl = nfs_false;
	bp += NFSX_UNSIGNED;
	nfsm_clget;
	if (eofflag)
		*tl = nfs_true;
	else
		*tl = nfs_false;
	bp += NFSX_UNSIGNED;
	if (mp != mb) {
		if (bp < be)
			mp->m_len = bp - mtod(mp, caddr_t);
	} else
		mp->m_len += bp - bpos;
	FREE(rbuf, M_TEMP);
	nfsm_srvdone;
}

nqnfsrv_readdirlook(nfsd, mrep, md, dpos, cred, nam, mrq)
	struct nfsd *nfsd;
	struct mbuf *mrep, *md;
	caddr_t dpos;
	struct ucred *cred;
	struct mbuf *nam, **mrq;
{
	register char *bp, *be;
	register struct mbuf *mp;
	register struct dirent *dp;
	register caddr_t cp;
	register u_long *tl;
	register long t1;
	caddr_t bpos;
	struct mbuf *mb, *mb2, *mreq, *mp2;
	char *cpos, *cend, *cp2, *rbuf;
	struct vnode *vp, *nvp;
	struct flrep fl;
	nfsv2fh_t nfh;
	fhandle_t *fhp;
	struct uio io;
	struct iovec iv;
	struct vattr va, *vap = &va;
	struct nfsv2_fattr *fp;
	int len, nlen, rem, xfer, tsiz, i, error = 0, duration2, cache2;
	int siz, cnt, fullsiz, eofflag, rdonly, cache;
	u_quad_t frev, frev2;
	u_long on, off, toff;

	fhp = &nfh.fh_generic;
	nfsm_srvmtofh(fhp);
	nfsm_dissect(tl, u_long *, 3*NFSX_UNSIGNED);
	toff = fxdr_unsigned(u_long, *tl++);
	off = (toff & ~(NFS_DIRBLKSIZ-1));
	on = (toff & (NFS_DIRBLKSIZ-1));
	cnt = fxdr_unsigned(int, *tl++);
	duration2 = fxdr_unsigned(int, *tl);
	siz = ((cnt+NFS_DIRBLKSIZ-1) & ~(NFS_DIRBLKSIZ-1));
	if (cnt > NFS_MAXREADDIR)
		siz = NFS_MAXREADDIR;
	fullsiz = siz;
	if (error = nfsrv_fhtovp(fhp, TRUE, &vp, cred, nfsd->nd_slp, nam, &rdonly))
		nfsm_reply(0);
	nqsrv_getl(vp, NQL_READ);
	if (error = nfsrv_access(vp, VEXEC, cred, rdonly, nfsd->nd_procp)) {
		vput(vp);
		nfsm_reply(0);
	}
	VOP_UNLOCK(vp);
	MALLOC(rbuf, caddr_t, siz, M_TEMP, M_WAITOK);
again:
	iv.iov_base = rbuf;
	iv.iov_len = fullsiz;
	io.uio_iov = &iv;
	io.uio_iovcnt = 1;
	io.uio_offset = (off_t)off;
	io.uio_resid = fullsiz;
	io.uio_segflg = UIO_SYSSPACE;
	io.uio_rw = UIO_READ;
	io.uio_procp = (struct proc *)0;
	error = VOP_READDIR(vp, &io, cred);
	off = (u_long)io.uio_offset;
	if (error) {
		vrele(vp);
		free((caddr_t)rbuf, M_TEMP);
		nfsm_reply(0);
	}
	if (io.uio_resid < fullsiz)
		eofflag = 0;
	else
		eofflag = 1;
	if (io.uio_resid) {
		siz -= io.uio_resid;

		/*
		 * If nothing read, return eof
		 * rpc reply
		 */
		if (siz == 0) {
			vrele(vp);
			nfsm_reply(2 * NFSX_UNSIGNED);
			nfsm_build(tl, u_long *, 2 * NFSX_UNSIGNED);
			*tl++ = nfs_false;
			*tl = nfs_true;
			FREE((caddr_t)rbuf, M_TEMP);
			return (0);
		}
	}

	/*
	 * Check for degenerate cases of nothing useful read.
	 * If so go try again
	 */
	cpos = rbuf + on;
	cend = rbuf + siz;
	dp = (struct dirent *)cpos;
	while (cpos < cend && dp->d_fileno == 0) {
		cpos += dp->d_reclen;
		dp = (struct dirent *)cpos;
	}
	if (cpos >= cend) {
		toff = off;
		siz = fullsiz;
		on = 0;
		goto again;
	}

	cpos = rbuf + on;
	cend = rbuf + siz;
	dp = (struct dirent *)cpos;
	len = 3 * NFSX_UNSIGNED;	/* paranoia, probably can be 0 */
	nfsm_reply(siz);
	mp = mp2 = mb;
	bp = bpos;
	be = bp + M_TRAILINGSPACE(mp);

	/* Loop through the records and build reply */
	while (cpos < cend) {
		if (dp->d_fileno != 0) {
			nlen = dp->d_namlen;
			rem = nfsm_rndup(nlen)-nlen;
	
			/*
			 * For readdir_and_lookup get the vnode using
			 * the file number.
			 */
			if (VFS_VGET(vp->v_mount, dp->d_fileno, &nvp))
				goto invalid;
			bzero((caddr_t)&fl.fl_nfh, sizeof (nfsv2fh_t));
			fl.fl_nfh.fh_generic.fh_fsid =
				nvp->v_mount->mnt_stat.f_fsid;
			if (VFS_VPTOFH(nvp, &fl.fl_nfh.fh_generic.fh_fid)) {
				vput(nvp);
				goto invalid;
			}
			if (duration2) {
				(void) nqsrv_getlease(nvp, &duration2, NQL_READ,
					nfsd, nam, &cache2, &frev2, cred);
				fl.fl_duration = txdr_unsigned(duration2);
				fl.fl_cachable = txdr_unsigned(cache2);
				txdr_hyper(&frev2, fl.fl_frev);
			} else
				fl.fl_duration = 0;
			if (VOP_GETATTR(nvp, vap, cred, nfsd->nd_procp)) {
				vput(nvp);
				goto invalid;
			}
			vput(nvp);
			fp = (struct nfsv2_fattr *)&fl.fl_fattr;
			nfsm_srvfillattr;
			len += (4*NFSX_UNSIGNED + nlen + rem + NFSX_FH
				+ NFSX_NQFATTR);
			if (len > cnt) {
				eofflag = 0;
				break;
			}
			/*
			 * Build the directory record xdr from
			 * the dirent entry.
			 */
			nfsm_clget;
			*tl = nfs_true;
			bp += NFSX_UNSIGNED;

			/*
			 * For readdir_and_lookup copy the stuff out.
			 */
			xfer = sizeof (struct flrep);
			cp = (caddr_t)&fl;
			while (xfer > 0) {
				nfsm_clget;
				if ((bp+xfer) > be)
					tsiz = be-bp;
				else
					tsiz = xfer;
				bcopy(cp, bp, tsiz);
				bp += tsiz;
				xfer -= tsiz;
				if (xfer > 0)
					cp += tsiz;
			}
			nfsm_clget;
			*tl = txdr_unsigned(dp->d_fileno);
			bp += NFSX_UNSIGNED;
			nfsm_clget;
			*tl = txdr_unsigned(nlen);
			bp += NFSX_UNSIGNED;
	
			/* And loop around copying the name */
			xfer = nlen;
			cp = dp->d_name;
			while (xfer > 0) {
				nfsm_clget;
				if ((bp+xfer) > be)
					tsiz = be-bp;
				else
					tsiz = xfer;
				bcopy(cp, bp, tsiz);
				bp += tsiz;
				xfer -= tsiz;
				if (xfer > 0)
					cp += tsiz;
			}
			/* And null pad to a long boundary */
			for (i = 0; i < rem; i++)
				*bp++ = '\0';
			nfsm_clget;
	
			/* Finish off the record */
			toff += dp->d_reclen;
			*tl = txdr_unsigned(toff);
			bp += NFSX_UNSIGNED;
		} else
invalid:
			toff += dp->d_reclen;
		cpos += dp->d_reclen;
		dp = (struct dirent *)cpos;
	}
	vrele(vp);
	nfsm_clget;
	*tl = nfs_false;
	bp += NFSX_UNSIGNED;
	nfsm_clget;
	if (eofflag)
		*tl = nfs_true;
	else
		*tl = nfs_false;
	bp += NFSX_UNSIGNED;
	if (mp != mb) {
		if (bp < be)
			mp->m_len = bp - mtod(mp, caddr_t);
	} else
		mp->m_len += bp - bpos;
	FREE(rbuf, M_TEMP);
	nfsm_srvdone;
}

/*
 * nfs statfs service
 */
nfsrv_statfs(nfsd, mrep, md, dpos, cred, nam, mrq)
	struct nfsd *nfsd;
	struct mbuf *mrep, *md;
	caddr_t dpos;
	struct ucred *cred;
	struct mbuf *nam, **mrq;
{
	register struct statfs *sf;
	register struct nfsv2_statfs *sfp;
	register u_long *tl;
	register long t1;
	caddr_t bpos;
	int error = 0, rdonly, cache, isnq;
	char *cp2;
	struct mbuf *mb, *mb2, *mreq;
	struct vnode *vp;
	nfsv2fh_t nfh;
	fhandle_t *fhp;
	struct statfs statfs;
	u_quad_t frev;

	fhp = &nfh.fh_generic;
	isnq = (nfsd->nd_nqlflag != NQL_NOVAL);
	nfsm_srvmtofh(fhp);
	if (error = nfsrv_fhtovp(fhp, TRUE, &vp, cred, nfsd->nd_slp, nam, &rdonly))
		nfsm_reply(0);
	sf = &statfs;
	error = VFS_STATFS(vp->v_mount, sf, nfsd->nd_procp);
	vput(vp);
	nfsm_reply(NFSX_STATFS(isnq));
	nfsm_build(sfp, struct nfsv2_statfs *, NFSX_STATFS(isnq));
	sfp->sf_tsize = txdr_unsigned(NFS_MAXDGRAMDATA);
	sfp->sf_bsize = txdr_unsigned(sf->f_bsize);
	sfp->sf_blocks = txdr_unsigned(sf->f_blocks);
	sfp->sf_bfree = txdr_unsigned(sf->f_bfree);
	sfp->sf_bavail = txdr_unsigned(sf->f_bavail);
	if (isnq) {
		sfp->sf_files = txdr_unsigned(sf->f_files);
		sfp->sf_ffree = txdr_unsigned(sf->f_ffree);
	}
	nfsm_srvdone;
}

/*
 * Null operation, used by clients to ping server
 */
/* ARGSUSED */
nfsrv_null(nfsd, mrep, md, dpos, cred, nam, mrq)
	struct nfsd *nfsd;
	struct mbuf *mrep, *md;
	caddr_t dpos;
	struct ucred *cred;
	struct mbuf *nam, **mrq;
{
	caddr_t bpos;
	int error = VNOVAL, cache;
	struct mbuf *mb, *mreq;
	u_quad_t frev;

	nfsm_reply(0);
	return (error);
}

/*
 * No operation, used for obsolete procedures
 */
/* ARGSUSED */
nfsrv_noop(nfsd, mrep, md, dpos, cred, nam, mrq)
	struct nfsd *nfsd;
	struct mbuf *mrep, *md;
	caddr_t dpos;
	struct ucred *cred;
	struct mbuf *nam, **mrq;
{
	caddr_t bpos;
	int error, cache;
	struct mbuf *mb, *mreq;
	u_quad_t frev;

	if (nfsd->nd_repstat)
		error = nfsd->nd_repstat;
	else
		error = EPROCUNAVAIL;
	nfsm_reply(0);
	return (error);
}

/*
 * Perform access checking for vnodes obtained from file handles that would
 * refer to files already opened by a Unix client. You cannot just use
 * vn_writechk() and VOP_ACCESS() for two reasons.
 * 1 - You must check for exported rdonly as well as MNT_RDONLY for the write case
 * 2 - The owner is to be given access irrespective of mode bits so that
 *     processes that chmod after opening a file don't break. I don't like
 *     this because it opens a security hole, but since the nfs server opens
 *     a security hole the size of a barn door anyhow, what the heck.
 */
nfsrv_access(vp, flags, cred, rdonly, p)
	register struct vnode *vp;
	int flags;
	register struct ucred *cred;
	int rdonly;
	struct proc *p;
{
	struct vattr vattr;
	int error;
	if (flags & VWRITE) {
		/* Just vn_writechk() changed to check rdonly */
		/*
		 * Disallow write attempts on read-only file systems;
		 * unless the file is a socket or a block or character
		 * device resident on the file system.
		 */
		if (rdonly || (vp->v_mount->mnt_flag & MNT_RDONLY)) {
			switch (vp->v_type) {
			case VREG: case VDIR: case VLNK:
				return (EROFS);
			}
		}
		/*
		 * If there's shared text associated with
		 * the inode, try to free it up once.  If
		 * we fail, we can't allow writing.
		 */
		if ((vp->v_flag & VTEXT) && !vnode_pager_uncache(vp))
			return (ETXTBSY);
	}
	if (error = VOP_GETATTR(vp, &vattr, cred, p))
		return (error);
	if ((error = VOP_ACCESS(vp, flags, cred, p)) &&
	    cred->cr_uid != vattr.va_uid)
		return (error);
	return (0);
}