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Commit db3f58a9 authored by J. Bruce Fields's avatar J. Bruce Fields
Browse files

rpc: define xdr_restrict_buflen 



With this xdr_reserve_space can help us enforce various limits.

Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 30596768

include/linux/sunrpc/xdr.h

+1 −0
Original line number Diff line number Diff line
@@ -217,6 +217,7 @@ extern void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 
extern __be32 *xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes);

extern void xdr_commit_encode(struct xdr_stream *xdr);

extern void xdr_truncate_encode(struct xdr_stream *xdr, size_t len);

extern int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen);

extern void xdr_write_pages(struct xdr_stream *xdr, struct page **pages,

		unsigned int base, unsigned int len);

extern unsigned int xdr_stream_pos(const struct xdr_stream *xdr);

net/sunrpc/xdr.c

+29 −0
Original line number Diff line number Diff line
@@ -648,6 +648,35 @@ void xdr_truncate_encode(struct xdr_stream *xdr, size_t len) 
}

EXPORT_SYMBOL(xdr_truncate_encode);



/**

 * xdr_restrict_buflen - decrease available buffer space

 * @xdr: pointer to xdr_stream

 * @newbuflen: new maximum number of bytes available

 *

 * Adjust our idea of how much space is available in the buffer.

 * If we've already used too much space in the buffer, returns -1.

 * If the available space is already smaller than newbuflen, returns 0

 * and does nothing.  Otherwise, adjusts xdr->buf->buflen to newbuflen

 * and ensures xdr->end is set at most offset newbuflen from the start

 * of the buffer.

 */

int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)

{

	struct xdr_buf *buf = xdr->buf;

	int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;

	int end_offset = buf->len + left_in_this_buf;



	if (newbuflen < 0 || newbuflen < buf->len)

		return -1;

	if (newbuflen > buf->buflen)

		return 0;

	if (newbuflen < end_offset)

		xdr->end = (void *)xdr->end + newbuflen - end_offset;

	buf->buflen = newbuflen;

	return 0;

}

EXPORT_SYMBOL(xdr_restrict_buflen);



/**

 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending

 * @xdr: pointer to xdr_stream