Commit bd8100e7 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Trond Myklebust
Browse files

[PATCH] RPC: Encode and decode arbitrary XDR arrays 



 Signed-off-by: default avatarAndreas Gruenbacher <agruen@suse.de>
 Acked-by: default avatarOlaf Kirch <okir@suse.de>
 Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 7e06b53d

include/linux/sunrpc/xdr.h

+18 −1
Original line number Diff line number Diff line
@@ -146,7 +146,8 @@ extern void xdr_shift_buf(struct xdr_buf *, size_t); 
extern void xdr_buf_from_iov(struct kvec *, struct xdr_buf *);

extern int xdr_buf_subsegment(struct xdr_buf *, struct xdr_buf *, int, int);

extern int xdr_buf_read_netobj(struct xdr_buf *, struct xdr_netobj *, int);

extern int read_bytes_from_xdr_buf(struct xdr_buf *buf, int base, void *obj, int len);

extern int read_bytes_from_xdr_buf(struct xdr_buf *, int, void *, int);

extern int write_bytes_to_xdr_buf(struct xdr_buf *, int, void *, int);



/*

 * Helper structure for copying from an sk_buff.
@@ -168,6 +169,22 @@ struct sockaddr; 
extern int xdr_sendpages(struct socket *, struct sockaddr *, int,

		struct xdr_buf *, unsigned int, int);



extern int xdr_encode_word(struct xdr_buf *, int, u32);

extern int xdr_decode_word(struct xdr_buf *, int, u32 *);



struct xdr_array2_desc;

typedef int (*xdr_xcode_elem_t)(struct xdr_array2_desc *desc, void *elem);

struct xdr_array2_desc {

	unsigned int elem_size;

	unsigned int array_len;

	xdr_xcode_elem_t xcode;

};



extern int xdr_decode_array2(struct xdr_buf *buf, unsigned int base,

                             struct xdr_array2_desc *desc);

extern int xdr_encode_array2(struct xdr_buf *buf, unsigned int base,

			     struct xdr_array2_desc *desc);



/*

 * Provide some simple tools for XDR buffer overflow-checking etc.

 */

net/sunrpc/sunrpc_syms.c

+4 −0
Original line number Diff line number Diff line
@@ -129,6 +129,10 @@ EXPORT_SYMBOL(xdr_encode_netobj); 
EXPORT_SYMBOL(xdr_encode_pages);

EXPORT_SYMBOL(xdr_inline_pages);

EXPORT_SYMBOL(xdr_shift_buf);

EXPORT_SYMBOL(xdr_encode_word);

EXPORT_SYMBOL(xdr_decode_word);

EXPORT_SYMBOL(xdr_encode_array2);

EXPORT_SYMBOL(xdr_decode_array2);

EXPORT_SYMBOL(xdr_buf_from_iov);

EXPORT_SYMBOL(xdr_buf_subsegment);

EXPORT_SYMBOL(xdr_buf_read_netobj);

net/sunrpc/xdr.c

+253 −3
Original line number Diff line number Diff line
@@ -887,8 +887,34 @@ read_bytes_from_xdr_buf(struct xdr_buf *buf, int base, void *obj, int len) 
	return status;

}



static int

read_u32_from_xdr_buf(struct xdr_buf *buf, int base, u32 *obj)

/* obj is assumed to point to allocated memory of size at least len: */

int

write_bytes_to_xdr_buf(struct xdr_buf *buf, int base, void *obj, int len)

{

	struct xdr_buf subbuf;

	int this_len;

	int status;



	status = xdr_buf_subsegment(buf, &subbuf, base, len);

	if (status)

		goto out;

	this_len = min(len, (int)subbuf.head[0].iov_len);

	memcpy(subbuf.head[0].iov_base, obj, this_len);

	len -= this_len;

	obj += this_len;

	this_len = min(len, (int)subbuf.page_len);

	if (this_len)

		_copy_to_pages(subbuf.pages, subbuf.page_base, obj, this_len);

	len -= this_len;

	obj += this_len;

	this_len = min(len, (int)subbuf.tail[0].iov_len);

	memcpy(subbuf.tail[0].iov_base, obj, this_len);

out:

	return status;

}



int

xdr_decode_word(struct xdr_buf *buf, int base, u32 *obj)

{

	u32	raw;

	int	status;
@@ -900,6 +926,14 @@ read_u32_from_xdr_buf(struct xdr_buf *buf, int base, u32 *obj) 
	return 0;

}



int

xdr_encode_word(struct xdr_buf *buf, int base, u32 obj)

{

	u32	raw = htonl(obj);



	return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));

}



/* If the netobj starting offset bytes from the start of xdr_buf is contained

 * entirely in the head or the tail, set object to point to it; otherwise

 * try to find space for it at the end of the tail, copy it there, and
@@ -910,7 +944,7 @@ xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, int offset) 
	u32	tail_offset = buf->head[0].iov_len + buf->page_len;

	u32	obj_end_offset;



	if (read_u32_from_xdr_buf(buf, offset, &obj->len))

	if (xdr_decode_word(buf, offset, &obj->len))

		goto out;

	obj_end_offset = offset + 4 + obj->len;
@@ -943,3 +977,219 @@ xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, int offset) 
out:

	return -1;

}



/* Returns 0 on success, or else a negative error code. */

static int

xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,

		 struct xdr_array2_desc *desc, int encode)

{

	char *elem = NULL, *c;

	unsigned int copied = 0, todo, avail_here;

	struct page **ppages = NULL;

	int err;



	if (encode) {

		if (xdr_encode_word(buf, base, desc->array_len) != 0)

			return -EINVAL;

	} else {

		if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||

		    (unsigned long) base + 4 + desc->array_len *

				    desc->elem_size > buf->len)

			return -EINVAL;

	}

	base += 4;



	if (!desc->xcode)

		return 0;



	todo = desc->array_len * desc->elem_size;



	/* process head */

	if (todo && base < buf->head->iov_len) {

		c = buf->head->iov_base + base;

		avail_here = min_t(unsigned int, todo,

				   buf->head->iov_len - base);

		todo -= avail_here;



		while (avail_here >= desc->elem_size) {

			err = desc->xcode(desc, c);

			if (err)

				goto out;

			c += desc->elem_size;

			avail_here -= desc->elem_size;

		}

		if (avail_here) {

			if (!elem) {

				elem = kmalloc(desc->elem_size, GFP_KERNEL);

				err = -ENOMEM;

				if (!elem)

					goto out;

			}

			if (encode) {

				err = desc->xcode(desc, elem);

				if (err)

					goto out;

				memcpy(c, elem, avail_here);

			} else

				memcpy(elem, c, avail_here);

			copied = avail_here;

		}

		base = buf->head->iov_len;  /* align to start of pages */

	}



	/* process pages array */

	base -= buf->head->iov_len;

	if (todo && base < buf->page_len) {

		unsigned int avail_page;



		avail_here = min(todo, buf->page_len - base);

		todo -= avail_here;



		base += buf->page_base;

		ppages = buf->pages + (base >> PAGE_CACHE_SHIFT);

		base &= ~PAGE_CACHE_MASK;

		avail_page = min_t(unsigned int, PAGE_CACHE_SIZE - base,

					avail_here);

		c = kmap(*ppages) + base;



		while (avail_here) {

			avail_here -= avail_page;

			if (copied || avail_page < desc->elem_size) {

				unsigned int l = min(avail_page,

					desc->elem_size - copied);

				if (!elem) {

					elem = kmalloc(desc->elem_size,

						       GFP_KERNEL);

					err = -ENOMEM;

					if (!elem)

						goto out;

				}

				if (encode) {

					if (!copied) {

						err = desc->xcode(desc, elem);

						if (err)

							goto out;

					}

					memcpy(c, elem + copied, l);

					copied += l;

					if (copied == desc->elem_size)

						copied = 0;

				} else {

					memcpy(elem + copied, c, l);

					copied += l;

					if (copied == desc->elem_size) {

						err = desc->xcode(desc, elem);

						if (err)

							goto out;

						copied = 0;

					}

				}

				avail_page -= l;

				c += l;

			}

			while (avail_page >= desc->elem_size) {

				err = desc->xcode(desc, c);

				if (err)

					goto out;

				c += desc->elem_size;

				avail_page -= desc->elem_size;

			}

			if (avail_page) {

				unsigned int l = min(avail_page,

					    desc->elem_size - copied);

				if (!elem) {

					elem = kmalloc(desc->elem_size,

						       GFP_KERNEL);

					err = -ENOMEM;

					if (!elem)

						goto out;

				}

				if (encode) {

					if (!copied) {

						err = desc->xcode(desc, elem);

						if (err)

							goto out;

					}

					memcpy(c, elem + copied, l);

					copied += l;

					if (copied == desc->elem_size)

						copied = 0;

				} else {

					memcpy(elem + copied, c, l);

					copied += l;

					if (copied == desc->elem_size) {

						err = desc->xcode(desc, elem);

						if (err)

							goto out;

						copied = 0;

					}

				}

			}

			if (avail_here) {

				kunmap(*ppages);

				ppages++;

				c = kmap(*ppages);

			}



			avail_page = min(avail_here,

				 (unsigned int) PAGE_CACHE_SIZE);

		}

		base = buf->page_len;  /* align to start of tail */

	}



	/* process tail */

	base -= buf->page_len;

	if (todo) {

		c = buf->tail->iov_base + base;

		if (copied) {

			unsigned int l = desc->elem_size - copied;



			if (encode)

				memcpy(c, elem + copied, l);

			else {

				memcpy(elem + copied, c, l);

				err = desc->xcode(desc, elem);

				if (err)

					goto out;

			}

			todo -= l;

			c += l;

		}

		while (todo) {

			err = desc->xcode(desc, c);

			if (err)

				goto out;

			c += desc->elem_size;

			todo -= desc->elem_size;

		}

	}

	err = 0;



out:

	if (elem)

		kfree(elem);

	if (ppages)

		kunmap(*ppages);

	return err;

}



int

xdr_decode_array2(struct xdr_buf *buf, unsigned int base,

		  struct xdr_array2_desc *desc)

{

	if (base >= buf->len)

		return -EINVAL;



	return xdr_xcode_array2(buf, base, desc, 0);

}



int

xdr_encode_array2(struct xdr_buf *buf, unsigned int base,

		  struct xdr_array2_desc *desc)

{

	if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >

	    buf->head->iov_len + buf->page_len + buf->tail->iov_len)

		return -EINVAL;



	return xdr_xcode_array2(buf, base, desc, 1);

}