From: Andreas Gruenbacher Add xdr_encode_array2 and xdr_decode_array2 functions for encoding end decoding arrays with arbitrary entries, such as acl entries. The goal here is to do this without allocating a contiguous temporary buffer. Signed-off-by: Andreas Gruenbacher Acked-by: Olaf Kirch Signed-off-by: Andrew Morton --- 25-akpm/include/linux/sunrpc/xdr.h | 19 ++- 25-akpm/net/sunrpc/sunrpc_syms.c | 4 25-akpm/net/sunrpc/xdr.c | 231 ++++++++++++++++++++++++++++++++++++- 3 files changed, 250 insertions(+), 4 deletions(-) diff -puN include/linux/sunrpc/xdr.h~nfsacl-encode-and-decode-arbitrary-xdr-arrays include/linux/sunrpc/xdr.h --- 25/include/linux/sunrpc/xdr.h~nfsacl-encode-and-decode-arbitrary-xdr-arrays 2005-01-23 01:27:54.119078976 -0800 +++ 25-akpm/include/linux/sunrpc/xdr.h 2005-01-23 01:27:54.126077912 -0800 @@ -146,7 +146,8 @@ extern void xdr_shift_buf(struct xdr_buf 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. */ diff -puN net/sunrpc/sunrpc_syms.c~nfsacl-encode-and-decode-arbitrary-xdr-arrays net/sunrpc/sunrpc_syms.c --- 25/net/sunrpc/sunrpc_syms.c~nfsacl-encode-and-decode-arbitrary-xdr-arrays 2005-01-23 01:27:54.121078672 -0800 +++ 25-akpm/net/sunrpc/sunrpc_syms.c 2005-01-23 01:27:54.126077912 -0800 @@ -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); diff -puN net/sunrpc/xdr.c~nfsacl-encode-and-decode-arbitrary-xdr-arrays net/sunrpc/xdr.c --- 25/net/sunrpc/xdr.c~nfsacl-encode-and-decode-arbitrary-xdr-arrays 2005-01-23 01:27:54.122078520 -0800 +++ 25-akpm/net/sunrpc/xdr.c 2005-01-23 01:27:54.128077608 -0800 @@ -868,8 +868,34 @@ out: 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; @@ -881,6 +907,14 @@ read_u32_from_xdr_buf(struct xdr_buf *bu 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 @@ -891,7 +925,7 @@ xdr_buf_read_netobj(struct xdr_buf *buf, 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; @@ -924,3 +958,194 @@ xdr_buf_read_netobj(struct xdr_buf *buf, 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[desc->elem_size], *c; + unsigned int copied = 0, todo, avail_here; + struct page **ppages = NULL; + int err = 0; + + 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 (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) { + 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; + unsigned int 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 (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 (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; + } + } + +out: + 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); +} _