nfs2xdr.c

linux 内核源代码

	p = xdr_encode_fhandle(p, args->fromfh);
	p = xdr_encode_array(p, args->fromname, args->fromlen);
	*p++ = htonl(args->pathlen);
	sndbuf->len = xdr_adjust_iovec(sndbuf->head, p);

	xdr_encode_pages(sndbuf, args->pages, 0, args->pathlen);

	/*
	 * xdr_encode_pages may have added a few bytes to ensure the
	 * pathname ends on a 4-byte boundary.  Start encoding the
	 * attributes after the pad bytes.
	 */
	pad = sndbuf->tail->iov_len;
	if (pad > 0)
		p++;
	p = xdr_encode_sattr(p, args->sattr);
	sndbuf->len += xdr_adjust_iovec(sndbuf->tail, p) - pad;
	return 0;
}

/*
 * Encode arguments to readdir call
 */
static int
nfs_xdr_readdirargs(struct rpc_rqst *req, __be32 *p, struct nfs_readdirargs *args)
{
	struct rpc_task	*task = req->rq_task;
	struct rpc_auth	*auth = task->tk_msg.rpc_cred->cr_auth;
	unsigned int replen;
	u32 count = args->count;

	p = xdr_encode_fhandle(p, args->fh);
	*p++ = htonl(args->cookie);
	*p++ = htonl(count); /* see above */
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);

	/* Inline the page array */
	replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS_readdirres_sz) << 2;
	xdr_inline_pages(&req->rq_rcv_buf, replen, args->pages, 0, count);
	return 0;
}

/*
 * Decode the result of a readdir call.
 * We're not really decoding anymore, we just leave the buffer untouched
 * and only check that it is syntactically correct.
 * The real decoding happens in nfs_decode_entry below, called directly
 * from nfs_readdir for each entry.
 */
static int
nfs_xdr_readdirres(struct rpc_rqst *req, __be32 *p, void *dummy)
{
	struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
	struct kvec *iov = rcvbuf->head;
	struct page **page;
	int hdrlen, recvd;
	int status, nr;
	unsigned int len, pglen;
	__be32 *end, *entry, *kaddr;

	if ((status = ntohl(*p++)))
		return -nfs_stat_to_errno(status);

	hdrlen = (u8 *) p - (u8 *) iov->iov_base;
	if (iov->iov_len < hdrlen) {
		dprintk("NFS: READDIR reply header overflowed:"
				"length %d > %Zu\n", hdrlen, iov->iov_len);
		return -errno_NFSERR_IO;
	} else if (iov->iov_len != hdrlen) {
		dprintk("NFS: READDIR header is short. iovec will be shifted.\n");
		xdr_shift_buf(rcvbuf, iov->iov_len - hdrlen);
	}

	pglen = rcvbuf->page_len;
	recvd = rcvbuf->len - hdrlen;
	if (pglen > recvd)
		pglen = recvd;
	page = rcvbuf->pages;
	kaddr = p = kmap_atomic(*page, KM_USER0);
	end = (__be32 *)((char *)p + pglen);
	entry = p;
	for (nr = 0; *p++; nr++) {
		if (p + 2 > end)
			goto short_pkt;
		p++; /* fileid */
		len = ntohl(*p++);
		p += XDR_QUADLEN(len) + 1;	/* name plus cookie */
		if (len > NFS2_MAXNAMLEN) {
			dprintk("NFS: giant filename in readdir (len 0x%x)!\n",
						len);
			goto err_unmap;
		}
		if (p + 2 > end)
			goto short_pkt;
		entry = p;
	}
	if (!nr && (entry[0] != 0 || entry[1] == 0))
		goto short_pkt;
 out:
	kunmap_atomic(kaddr, KM_USER0);
	return nr;
 short_pkt:
	entry[0] = entry[1] = 0;
	/* truncate listing ? */
	if (!nr) {
		dprintk("NFS: readdir reply truncated!\n");
		entry[1] = 1;
	}
	goto out;
err_unmap:
	nr = -errno_NFSERR_IO;
	goto out;
}

__be32 *
nfs_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus)
{
	if (!*p++) {
		if (!*p)
			return ERR_PTR(-EAGAIN);
		entry->eof = 1;
		return ERR_PTR(-EBADCOOKIE);
	}

	entry->ino	  = ntohl(*p++);
	entry->len	  = ntohl(*p++);
	entry->name	  = (const char *) p;
	p		 += XDR_QUADLEN(entry->len);
	entry->prev_cookie	  = entry->cookie;
	entry->cookie	  = ntohl(*p++);
	entry->eof	  = !p[0] && p[1];

	return p;
}

/*
 * NFS XDR decode functions
 */
/*
 * Decode simple status reply
 */
static int
nfs_xdr_stat(struct rpc_rqst *req, __be32 *p, void *dummy)
{
	int	status;

	if ((status = ntohl(*p++)) != 0)
		status = -nfs_stat_to_errno(status);
	return status;
}

/*
 * Decode attrstat reply
 * GETATTR, SETATTR, WRITE
 */
static int
nfs_xdr_attrstat(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr)
{
	int	status;

	if ((status = ntohl(*p++)))
		return -nfs_stat_to_errno(status);
	xdr_decode_fattr(p, fattr);
	return 0;
}

/*
 * Decode diropres reply
 * LOOKUP, CREATE, MKDIR
 */
static int
nfs_xdr_diropres(struct rpc_rqst *req, __be32 *p, struct nfs_diropok *res)
{
	int	status;

	if ((status = ntohl(*p++)))
		return -nfs_stat_to_errno(status);
	p = xdr_decode_fhandle(p, res->fh);
	xdr_decode_fattr(p, res->fattr);
	return 0;
}

/*
 * Encode READLINK args
 */
static int
nfs_xdr_readlinkargs(struct rpc_rqst *req, __be32 *p, struct nfs_readlinkargs *args)
{
	struct rpc_auth	*auth = req->rq_task->tk_msg.rpc_cred->cr_auth;
	unsigned int replen;

	p = xdr_encode_fhandle(p, args->fh);
	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);

	/* Inline the page array */
	replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS_readlinkres_sz) << 2;
	xdr_inline_pages(&req->rq_rcv_buf, replen, args->pages, args->pgbase, args->pglen);
	return 0;
}

/*
 * Decode READLINK reply
 */
static int
nfs_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, void *dummy)
{
	struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
	struct kvec *iov = rcvbuf->head;
	int hdrlen, len, recvd;
	char	*kaddr;
	int	status;

	if ((status = ntohl(*p++)))
		return -nfs_stat_to_errno(status);
	/* Convert length of symlink */
	len = ntohl(*p++);
	if (len >= rcvbuf->page_len || len <= 0) {
		dprintk("nfs: server returned giant symlink!\n");
		return -ENAMETOOLONG;
	}
	hdrlen = (u8 *) p - (u8 *) iov->iov_base;
	if (iov->iov_len < hdrlen) {
		dprintk("NFS: READLINK reply header overflowed:"
				"length %d > %Zu\n", hdrlen, iov->iov_len);
		return -errno_NFSERR_IO;
	} else if (iov->iov_len != hdrlen) {
		dprintk("NFS: READLINK header is short. iovec will be shifted.\n");
		xdr_shift_buf(rcvbuf, iov->iov_len - hdrlen);
	}
	recvd = req->rq_rcv_buf.len - hdrlen;
	if (recvd < len) {
		dprintk("NFS: server cheating in readlink reply: "
				"count %u > recvd %u\n", len, recvd);
		return -EIO;
	}

	/* NULL terminate the string we got */
	kaddr = (char *)kmap_atomic(rcvbuf->pages[0], KM_USER0);
	kaddr[len+rcvbuf->page_base] = '\0';
	kunmap_atomic(kaddr, KM_USER0);
	return 0;
}

/*
 * Decode WRITE reply
 */
static int
nfs_xdr_writeres(struct rpc_rqst *req, __be32 *p, struct nfs_writeres *res)
{
	res->verf->committed = NFS_FILE_SYNC;
	return nfs_xdr_attrstat(req, p, res->fattr);
}

/*
 * Decode STATFS reply
 */
static int
nfs_xdr_statfsres(struct rpc_rqst *req, __be32 *p, struct nfs2_fsstat *res)
{
	int	status;

	if ((status = ntohl(*p++)))
		return -nfs_stat_to_errno(status);

	res->tsize  = ntohl(*p++);
	res->bsize  = ntohl(*p++);
	res->blocks = ntohl(*p++);
	res->bfree  = ntohl(*p++);
	res->bavail = ntohl(*p++);
	return 0;
}

/*
 * We need to translate between nfs status return values and
 * the local errno values which may not be the same.
 */
static struct {
	int stat;
	int errno;
} nfs_errtbl[] = {
	{ NFS_OK,		0		},
	{ NFSERR_PERM,		EPERM		},
	{ NFSERR_NOENT,		ENOENT		},
	{ NFSERR_IO,		errno_NFSERR_IO	},
	{ NFSERR_NXIO,		ENXIO		},
/*	{ NFSERR_EAGAIN,	EAGAIN		}, */
	{ NFSERR_ACCES,		EACCES		},
	{ NFSERR_EXIST,		EEXIST		},
	{ NFSERR_XDEV,		EXDEV		},
	{ NFSERR_NODEV,		ENODEV		},
	{ NFSERR_NOTDIR,	ENOTDIR		},
	{ NFSERR_ISDIR,		EISDIR		},
	{ NFSERR_INVAL,		EINVAL		},
	{ NFSERR_FBIG,		EFBIG		},
	{ NFSERR_NOSPC,		ENOSPC		},
	{ NFSERR_ROFS,		EROFS		},
	{ NFSERR_MLINK,		EMLINK		},
	{ NFSERR_NAMETOOLONG,	ENAMETOOLONG	},
	{ NFSERR_NOTEMPTY,	ENOTEMPTY	},
	{ NFSERR_DQUOT,		EDQUOT		},
	{ NFSERR_STALE,		ESTALE		},
	{ NFSERR_REMOTE,	EREMOTE		},
#ifdef EWFLUSH
	{ NFSERR_WFLUSH,	EWFLUSH		},
#endif
	{ NFSERR_BADHANDLE,	EBADHANDLE	},
	{ NFSERR_NOT_SYNC,	ENOTSYNC	},
	{ NFSERR_BAD_COOKIE,	EBADCOOKIE	},
	{ NFSERR_NOTSUPP,	ENOTSUPP	},
	{ NFSERR_TOOSMALL,	ETOOSMALL	},
	{ NFSERR_SERVERFAULT,	ESERVERFAULT	},
	{ NFSERR_BADTYPE,	EBADTYPE	},
	{ NFSERR_JUKEBOX,	EJUKEBOX	},
	{ -1,			EIO		}
};

/*
 * Convert an NFS error code to a local one.
 * This one is used jointly by NFSv2 and NFSv3.
 */
int
nfs_stat_to_errno(int stat)
{
	int i;

	for (i = 0; nfs_errtbl[i].stat != -1; i++) {
		if (nfs_errtbl[i].stat == stat)
			return nfs_errtbl[i].errno;
	}
	dprintk("nfs_stat_to_errno: bad nfs status return value: %d\n", stat);
	return nfs_errtbl[i].errno;
}

#define PROC(proc, argtype, restype, timer)				\
[NFSPROC_##proc] = {							\
	.p_proc	    =  NFSPROC_##proc,					\
	.p_encode   =  (kxdrproc_t) nfs_xdr_##argtype,			\
	.p_decode   =  (kxdrproc_t) nfs_xdr_##restype,			\
	.p_arglen   =  NFS_##argtype##_sz,				\
	.p_replen   =  NFS_##restype##_sz,				\
	.p_timer    =  timer,						\
	.p_statidx  =  NFSPROC_##proc,					\
	.p_name     =  #proc,						\
	}
struct rpc_procinfo	nfs_procedures[] = {
    PROC(GETATTR,	fhandle,	attrstat, 1),
    PROC(SETATTR,	sattrargs,	attrstat, 0),
    PROC(LOOKUP,	diropargs,	diropres, 2),
    PROC(READLINK,	readlinkargs,	readlinkres, 3),
    PROC(READ,		readargs,	readres, 3),
    PROC(WRITE,		writeargs,	writeres, 4),
    PROC(CREATE,	createargs,	diropres, 0),
    PROC(REMOVE,	removeargs,	stat, 0),
    PROC(RENAME,	renameargs,	stat, 0),
    PROC(LINK,		linkargs,	stat, 0),
    PROC(SYMLINK,	symlinkargs,	stat, 0),
    PROC(MKDIR,		createargs,	diropres, 0),
    PROC(RMDIR,		diropargs,	stat, 0),
    PROC(READDIR,	readdirargs,	readdirres, 3),
    PROC(STATFS,	fhandle,	statfsres, 0),
};

struct rpc_version		nfs_version2 = {
	.number			= 2,
	.nrprocs		= ARRAY_SIZE(nfs_procedures),
	.procs			= nfs_procedures
};