- 根目录:
- net
- sunrpc
- xdr.c
/*
* linux/net/sunrpc/xdr.c
*
* Generic XDR support.
*
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/pagemap.h>
#include <linux/errno.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/msg_prot.h>
/*
* XDR functions for basic NFS types
*/
__be32 *
xdr_encode_netobj(__be32 *p, const struct xdr_netobj *obj)
{
unsigned int quadlen = XDR_QUADLEN(obj->len);
p[quadlen] = 0; /* zero trailing bytes */
*p++ = cpu_to_be32(obj->len);
memcpy(p, obj->data, obj->len);
return p + XDR_QUADLEN(obj->len);
}
EXPORT_SYMBOL_GPL(xdr_encode_netobj);
__be32 *
xdr_decode_netobj(__be32 *p, struct xdr_netobj *obj)
{
unsigned int len;
if ((len = be32_to_cpu(*p++)) > XDR_MAX_NETOBJ)
return NULL;
obj->len = len;
obj->data = (u8 *) p;
return p + XDR_QUADLEN(len);
}
EXPORT_SYMBOL_GPL(xdr_decode_netobj);
/**
* xdr_encode_opaque_fixed - Encode fixed length opaque data
* @p: pointer to current position in XDR buffer.
* @ptr: pointer to data to encode (or NULL)
* @nbytes: size of data.
*
* Copy the array of data of length nbytes at ptr to the XDR buffer
* at position p, then align to the next 32-bit boundary by padding
* with zero bytes (see RFC1832).
* Note: if ptr is NULL, only the padding is performed.
*
* Returns the updated current XDR buffer position
*
*/
__be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int nbytes)
{
if (likely(nbytes != 0)) {
unsigned int quadlen = XDR_QUADLEN(nbytes);
unsigned int padding = (quadlen << 2) - nbytes;
if (ptr != NULL)
memcpy(p, ptr, nbytes);
if (padding != 0)
memset((char *)p + nbytes, 0, padding);
p += quadlen;
}
return p;
}
EXPORT_SYMBOL_GPL(xdr_encode_opaque_fixed);
/**
* xdr_encode_opaque - Encode variable length opaque data
* @p: pointer to current position in XDR buffer.
* @ptr: pointer to data to encode (or NULL)
* @nbytes: size of data.
*
* Returns the updated current XDR buffer position
*/
__be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
{
*p++ = cpu_to_be32(nbytes);
return xdr_encode_opaque_fixed(p, ptr, nbytes);
}
EXPORT_SYMBOL_GPL(xdr_encode_opaque);
__be32 *
xdr_encode_string(__be32 *p, const char *string)
{
return xdr_encode_array(p, string, strlen(string));
}
EXPORT_SYMBOL_GPL(xdr_encode_string);
__be32 *
xdr_decode_string_inplace(__be32 *p, char **sp,
unsigned int *lenp, unsigned int maxlen)
{
u32 len;
len = be32_to_cpu(*p++);
if (len > maxlen)
return NULL;
*lenp = len;
*sp = (char *) p;
return p + XDR_QUADLEN(len);
}
EXPORT_SYMBOL_GPL(xdr_decode_string_inplace);
/**
* xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf
* @buf: XDR buffer where string resides
* @len: length of string, in bytes
*
*/
void
xdr_terminate_string(struct xdr_buf *buf, const u32 len)
{
char *kaddr;
kaddr = kmap_atomic(buf->pages[0]);
kaddr[buf->page_base + len] = '\0';
kunmap_atomic(kaddr);
}
EXPORT_SYMBOL_GPL(xdr_terminate_string);
void
xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
struct page **pages, unsigned int base, unsigned int len)
{
struct kvec *head = xdr->head;
struct kvec *tail = xdr->tail;
char *buf = (char *)head->iov_base;
unsigned int buflen = head->iov_len;
head->iov_len = offset;
xdr->pages = pages;
xdr->page_base = base;
xdr->page_len = len;
tail->iov_base = buf + offset;
tail->iov_len = buflen - offset;
xdr->buflen += len;
}
EXPORT_SYMBOL_GPL(xdr_inline_pages);
/*
* Helper routines for doing 'memmove' like operations on a struct xdr_buf
*/
/**
* _shift_data_right_pages
* @pages: vector of pages containing both the source and dest memory area.
* @pgto_base: page vector address of destination
* @pgfrom_base: page vector address of source
* @len: number of bytes to copy
*
* Note: the addresses pgto_base and pgfrom_base are both calculated in
* the same way:
* if a memory area starts at byte 'base' in page 'pages[i]',
* then its address is given as (i << PAGE_CACHE_SHIFT) + base
* Also note: pgfrom_base must be < pgto_base, but the memory areas
* they point to may overlap.
*/
static void
_shift_data_right_pages(struct page **pages, size_t pgto_base,
size_t pgfrom_base, size_t len)
{
struct page **pgfrom, **pgto;
char *vfrom, *vto;
size_t copy;
BUG_ON(pgto_base <= pgfrom_base);
pgto_base += len;
pgfrom_base += len;
pgto = pages + (pgto_base >> PAGE_CACHE_SHIFT);
pgfrom = pages + (pgfrom_base >> PAGE_CACHE_SHIFT);
pgto_base &= ~PAGE_CACHE_MASK;
pgfrom_base &= ~PAGE_CACHE_MASK;
do {
/* Are any pointers crossing a page boundary? */
if (pgto_base == 0) {
pgto_base = PAGE_CACHE_SIZE;
pgto--;
}
if (pgfrom_base == 0) {
pgfrom_base = PAGE_CACHE_SIZE;
pgfrom--;
}
copy = len;
if (copy > pgto_base)
copy = pgto_base;
if (copy > pgfrom_base)
copy = pgfrom_base;
pgto_base -= copy;
pgfrom_base -= copy;
vto = kmap_atomic(*pgto);
if (*pgto != *pgfrom) {
vfrom = kmap_atomic(*pgfrom);
memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
kunmap_atomic(vfrom);
} else
memmove(vto + pgto_base, vto + pgfrom_base, copy);
flush_dcache_page(*pgto);
kunmap_atomic(vto);
} while ((len -= copy) != 0);
}
/**
* _copy_to_pages
* @pages: array of pages
* @pgbase: page vector address of destination
* @p: pointer to source data
* @len: length
*
* Copies data from an arbitrary memory location into an array of pages
* The copy is assumed to be non-overlapping.
*/
static void
_copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
{
struct page **pgto;
char *vto;
size_t copy;
pgto = pages + (pgbase >> PAGE_CACHE_SHIFT);
pgbase &= ~PAGE_CACHE_MASK;
for (;;) {
copy = PAGE_CACHE_SIZE - pgbase;
if (copy > len)
copy = len;
vto = kmap_atomic(*pgto);
memcpy(vto + pgbase, p, copy);
kunmap_atomic(vto);
len -= copy;
if (len == 0)
break;
pgbase += copy;
if (pgbase == PAGE_CACHE_SIZE) {
flush_dcache_page(*pgto);
pgbase = 0;
pgto++;
}
p += copy;
}
flush_dcache_page(*pgto);
}
/**
* _copy_from_pages
* @p: pointer to destination
* @pages: array of pages
* @pgbase: offset of source data
* @len: length
*
* Copies data into an arbitrary memory location from an array of pages
* The copy is assumed to be non-overlapping.
*/
void
_copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
{
struct page **pgfrom;
char *vfrom;
size_t copy;
pgfrom = pages + (pgbase >> PAGE_CACHE_SHIFT);
pgbase &= ~PAGE_CACHE_MASK;
do {
copy = PAGE_CACHE_SIZE - pgbase;
if (copy > len)
copy = len;
vfrom = kmap_atomic(*pgfrom);
memcpy(p, vfrom + pgbase, copy);
kunmap_atomic(vfrom);
pgbase += copy;
if (pgbase == PAGE_CACHE_SIZE) {
pgbase = 0;
pgfrom++;
}
p += copy;
} while ((len -= copy) != 0);
}
EXPORT_SYMBOL_GPL(_copy_from_pages);
/**
* xdr_shrink_bufhead
* @buf: xdr_buf
* @len: bytes to remove from buf->head[0]
*
* Shrinks XDR buffer's header kvec buf->head[0] by
* 'len' bytes. The extra data is not lost, but is instead
* moved into the inlined pages and/or the tail.
*/
static void
xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
{
struct kvec *head, *tail;
size_t copy, offs;
unsigned int pglen = buf->page_len;
tail = buf->tail;
head = buf->head;
WARN_ON_ONCE(len > head->iov_len);
if (len > head->iov_len)
len = head->iov_len;
/* Shift the tail first */
if (tail->iov_len != 0) {
if (tail->iov_len > len) {
copy = tail->iov_len - len;
memmove((char *)tail->iov_base + len,
tail->iov_base, copy);
}
/* Copy from the inlined pages into the tail */
copy = len;
if (copy > pglen)
copy = pglen;
offs = len - copy;
if (offs >= tail->iov_len)
copy = 0;
else if (copy > tail->iov_len - offs)
copy = tail->iov_len - offs;
if (copy != 0)
_copy_from_pages((char *)tail->iov_base + offs,
buf->pages,
buf->page_base + pglen + offs - len,
copy);
/* Do we also need to copy data from the head into the tail ? */
if (len > pglen) {
offs = copy = len - pglen;
if (copy > tail->iov_len)
copy = tail->iov_len;
memcpy(tail->iov_base,
(char *)head->iov_base +
head->iov_len - offs,
copy);
}
}
/* Now handle pages */
if (pglen != 0) {
if (pglen > len)
_shift_data_right_pages(buf->pages,
buf->page_base + len,
buf->page_base,
pglen - len);
copy = len;
if (len > pglen)
copy = pglen;
_copy_to_pages(buf->pages, buf->page_base,
(char *)head->iov_base + head->iov_len - len,
copy);
}
head->iov_len -= len;
buf->buflen -= len;
/* Have we truncated the message? */
if (buf->len > buf->buflen)
buf->len = buf->buflen;
}
/**
* xdr_shrink_pagelen
* @buf: xdr_buf
* @len: bytes to remove from buf->pages
*
* Shrinks XDR buffer's page array buf->pages by
* 'len' bytes. The extra data is not lost, but is instead
* moved into the tail.
*/
static void
xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
{
struct kvec *tail;
size_t copy;
unsigned int pglen = buf->page_len;
unsigned int tailbuf_len;
tail = buf->tail;
BUG_ON (len > pglen);
tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
/* Shift the tail first */
if (tailbuf_len != 0) {
unsigned int free_space = tailbuf_len - tail->iov_len;
if (len < free_space)
free_space = len;
tail->iov_len += free_space;
copy = len;
if (tail->iov_len > len) {
char *p = (char *)tail->iov_base + len;
memmove(p, tail->iov_base, tail->iov_len - len);
} else
copy = tail->iov_len;
/* Copy from the inlined pages into the tail */
_copy_from_pages((char *)tail->iov_base,
buf->pages, buf->page_base + pglen - len,
copy);
}
buf->page_len -= len;
buf->buflen -= len;
/* Have we truncated the message? */
if (buf->len > buf->buflen)
buf->len = buf->buflen;
}
void
xdr_shift_buf(struct xdr_buf *buf, size_t len)
{
xdr_shrink_bufhead(buf, len);
}
EXPORT_SYMBOL_GPL(xdr_shift_buf);
/**
* xdr_stream_pos - Return the current offset from the start of the xdr_stream
* @xdr: pointer to struct xdr_stream
*/
unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
{
return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
}
EXPORT_SYMBOL_GPL(xdr_stream_pos);
/**
* xdr_init_encode - Initialize a struct xdr_stream for sending data.
* @xdr: pointer to xdr_stream struct
* @buf: pointer to XDR buffer in which to encode data
* @p: current pointer inside XDR buffer
*
* Note: at the moment the RPC client only passes the length of our
* scratch buffer in the xdr_buf's header kvec. Previously this
* meant we needed to call xdr_adjust_iovec() after encoding the
* data. With the new scheme, the xdr_stream manages the details
* of the buffer length, and takes care of adjusting the kvec
* length for us.
*/
void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
{
struct kvec *iov = buf->head;
int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
xdr_set_scratch_buffer(xdr, NULL, 0);
BUG_ON(scratch_len < 0);
xdr->buf = buf;
xdr->iov = iov;
xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
BUG_ON(iov->iov_len > scratch_len);
if (p != xdr->p && p != NULL) {
size_t len;
BUG_ON(p < xdr->p || p > xdr->end);
len = (char *)p - (char *)xdr->p;
xdr->p = p;
buf->len += len;
iov->iov_len += len;
}
}
EXPORT_SYMBOL_GPL(xdr_init_encode);
/**
* xdr_commit_encode - Ensure all data is written to buffer
* @xdr: pointer to xdr_stream
*
* We handle encoding across page boundaries by giving the caller a
* temporary location to write to, then later copying the data into
* place; xdr_commit_encode does that copying.
*
* Normally the caller doesn't need to call this directly, as the
* following xdr_reserve_space will do it. But an explicit call may be
* required at the end of encoding, or any other time when the xdr_buf
* data might be read.
*/
void xdr_commit_encode(struct xdr_stream *xdr)
{
int shift = xdr->scratch.iov_len;
void *page;
if (shift == 0)
return;
page = page_address(*xdr->page_ptr);
memcpy(xdr->scratch.iov_base, page, shift);
memmove(page, page + shift, (void *)xdr->p - page);
xdr->scratch.iov_len = 0;
}
EXPORT_SYMBOL_GPL(xdr_commit_encode);
static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
size_t nbytes)
{
static __be32 *p;
int space_left;
int frag1bytes, frag2bytes;
if (nbytes > PAGE_SIZE)
return NULL; /* Bigger buffers require special handling */
if (xdr->buf->len + nbytes > xdr->buf->buflen)
return NULL; /* Sorry, we're totally out of space */
frag1bytes = (xdr->end - xdr->p) << 2;
frag2bytes = nbytes - frag1bytes;
if (xdr->iov)
xdr->iov->iov_len += frag1bytes;
else
xdr->buf->page_len += frag1bytes;
xdr->page_ptr++;
xdr->iov = NULL;
/*
* If the last encode didn't end exactly on a page boundary, the
* next one will straddle boundaries. Encode into the next
* page, then copy it back later in xdr_commit_encode. We use
* the "scratch" iov to track any temporarily unused fragment of
* space at the end of the previous buffer:
*/
xdr->scratch.iov_base = xdr->p;
xdr->scratch.iov_len = frag1bytes;
p = page_address(*xdr->page_ptr);
/*
* Note this is where the next encode will start after we've
* shifted this one back:
*/
xdr->p = (void *)p + frag2bytes;
space_left = xdr->buf->buflen - xdr->buf->len;
xdr->end = (void *)p + min_t(int, space_left, PAGE_SIZE);
xdr->buf->page_len += frag2bytes;
xdr->buf->len += nbytes;
return p;
}
/**
* xdr_reserve_space - Reserve buffer space for sending
* @xdr: pointer to xdr_stream
* @nbytes: number of bytes to reserve
*
* Checks that we have enough buffer space to encode 'nbytes' more
* bytes of data. If so, update the total xdr_buf length, and
* adjust the length of the current kvec.
*/
__be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
{
__be32 *p = xdr->p;
__be32 *q;
xdr_commit_encode(xdr);
/* align nbytes on the next 32-bit boundary */
nbytes += 3;
nbytes &= ~3;
q = p + (nbytes >> 2);
if (unlikely(q > xdr->end || q < p))
return xdr_get_next_encode_buffer(xdr, nbytes);
xdr->p = q;
if (xdr->iov)
xdr->iov->iov_len += nbytes;
else
xdr->buf->page_len += nbytes;
xdr->buf->len += nbytes;
return p;
}
EXPORT_SYMBOL_GPL(xdr_reserve_space);
/**
* xdr_truncate_encode - truncate an encode buffer
* @xdr: pointer to xdr_stream
* @len: new length of buffer
*
* Truncates the xdr stream, so that xdr->buf->len == len,
* and xdr->p points at offset len from the start of the buffer, and
* head, tail, and page lengths are adjusted to correspond.
*
* If this means moving xdr->p to a different buffer, we assume that
* that the end pointer should be set to the end of the current page,
* except in the case of the head buffer when we assume the head
* buffer's current length represents the end of the available buffer.
*
* This is *not* safe to use on a buffer that already has inlined page
* cache pages (as in a zero-copy server read reply), except for the
* simple case of truncating from one position in the tail to another.
*
*/
void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
{
struct xdr_buf *buf = xdr->buf;
struct kvec *head = buf->head;
struct kvec *tail = buf->tail;
int fraglen;
int new;
if (len > buf->len) {
WARN_ON_ONCE(1);
return;
}
xdr_commit_encode(xdr);
fraglen = min_t(int, buf->len - len, tail->iov_len);
tail->iov_len -= fraglen;
buf->len -= fraglen;
if (tail->iov_len) {
xdr->p = tail->iov_base + tail->iov_len;
WARN_ON_ONCE(!xdr->end);
WARN_ON_ONCE(!xdr->iov);
return;
}
WARN_ON_ONCE(fraglen);
fraglen = min_t(int, buf->len - len, buf->page_len);
buf->page_len -= fraglen;
buf->len -= fraglen;
new = buf->page_base + buf->page_len;
xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
if (buf->page_len) {
xdr->p = page_address(*xdr->page_ptr);
xdr->end = (void *)xdr->p + PAGE_SIZE;
xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
WARN_ON_ONCE(xdr->iov);
return;
}
if (fraglen) {
xdr->end = head->iov_base + head->iov_len;
xdr->page_ptr--;
}
/* (otherwise assume xdr->end is already set) */
head->iov_len = len;
buf->len = len;
xdr->p = head->iov_base + head->iov_len;
xdr->iov = buf->head;
}
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
* @pages: list of pages
* @base: offset of first byte
* @len: length of data in bytes
*
*/
void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
unsigned int len)
{
struct xdr_buf *buf = xdr->buf;
struct kvec *iov = buf->tail;
buf->pages = pages;
buf->page_base = base;
buf->page_len = len;
iov->iov_base = (char *)xdr->p;
iov->iov_len = 0;
xdr->iov = iov;
if (len & 3) {
unsigned int pad = 4 - (len & 3);
BUG_ON(xdr->p >= xdr->end);
iov->iov_base = (char *)xdr->p + (len & 3);
iov->iov_len += pad;
len += pad;
*xdr->p++ = 0;
}
buf->buflen += len;
buf->len += len;
}
EXPORT_SYMBOL_GPL(xdr_write_pages);
static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
unsigned int len)
{
if (len > iov->iov_len)
len = iov->iov_len;
xdr->p = (__be32*)iov->iov_base;
xdr->end = (__be32*)(iov->iov_base + len);
xdr->iov = iov;
xdr->page_ptr = NULL;
}
static int xdr_set_page_base(struct xdr_stream *xdr,
unsigned int base, unsigned int len)
{
unsigned int pgnr;
unsigned int maxlen;
unsigned int pgoff;
unsigned int pgend;
void *kaddr;
maxlen = xdr->buf->page_len;
if (base >= maxlen)
return -EINVAL;
maxlen -= base;
if (len > maxlen)
len = maxlen;
base += xdr->buf->page_base;
pgnr = base >> PAGE_SHIFT;
xdr->page_ptr = &xdr->buf->pages[pgnr];
kaddr = page_address(*xdr->page_ptr);
pgoff = base & ~PAGE_MASK;
xdr->p = (__be32*)(kaddr + pgoff);
pgend = pgoff + len;
if (pgend > PAGE_SIZE)
pgend = PAGE_SIZE;
xdr->end = (__be32*)(kaddr + pgend);
xdr->iov = NULL;
return 0;
}
static void xdr_set_next_page(struct xdr_stream *xdr)
{
unsigned int newbase;
newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
newbase -= xdr->buf->page_base;
if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0)
xdr_set_iov(xdr, xdr->buf->tail, xdr->buf->len);
}
static bool xdr_set_next_buffer(struct xdr_stream *xdr)
{
if (xdr->page_ptr != NULL)
xdr_set_next_page(xdr);
else if (xdr->iov == xdr->buf->head) {
if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0)
xdr_set_iov(xdr, xdr->buf->tail, xdr->buf->len);
}
return xdr->p != xdr->end;
}
/**
* xdr_init_decode - Initialize an xdr_stream for decoding data.
* @xdr: pointer to xdr_stream struct
* @buf: pointer to XDR buffer from which to decode data
* @p: current pointer inside XDR buffer
*/
void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
{
xdr->buf = buf;
xdr->scratch.iov_base = NULL;
xdr->scratch.iov_len = 0;
xdr->nwords = XDR_QUADLEN(buf->len);
if (buf->head[0].iov_len != 0)
xdr_set_iov(xdr, buf->head, buf->len);
else if (buf->page_len != 0)
xdr_set_page_base(xdr, 0, buf->len);
if (p != NULL && p > xdr->p && xdr->end >= p) {
xdr->nwords -= p - xdr->p;
xdr->p = p;
}
}
EXPORT_SYMBOL_GPL(xdr_init_decode);
/**
* xdr_init_decode - Initialize an xdr_stream for decoding data.
* @xdr: pointer to xdr_stream struct
* @buf: pointer to XDR buffer from which to decode data
* @pages: list of pages to decode into
* @len: length in bytes of buffer in pages
*/
void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
struct page **pages, unsigned int len)
{
memset(buf, 0, sizeof(*buf));
buf->pages = pages;
buf->page_len = len;
buf->buflen = len;
buf->len = len;
xdr_init_decode(xdr, buf, NULL);
}
EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
{
unsigned int nwords = XDR_QUADLEN(nbytes);
__be32 *p = xdr->p;
__be32 *q = p + nwords;
if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
return NULL;
xdr->p = q;
xdr->nwords -= nwords;
return p;
}
/**
* xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
* @xdr: pointer to xdr_stream struct
* @buf: pointer to an empty buffer
* @buflen: size of 'buf'
*
* The scratch buffer is used when decoding from an array of pages.
* If an xdr_inline_decode() call spans across page boundaries, then
* we copy the data into the scratch buffer in order to allow linear
* access.
*/
void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
{
xdr->scratch.iov_base = buf;
xdr->scratch.iov_len = buflen;
}
EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer);
static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
{
__be32 *p;
void *cpdest = xdr->scratch.iov_base;
size_t cplen = (char *)xdr->end - (char *)xdr->p;
if (nbytes > xdr->scratch.iov_len)
return NULL;
memcpy(cpdest, xdr->p, cplen);
cpdest += cplen;
nbytes -= cplen;
if (!xdr_set_next_buffer(xdr))
return NULL;
p = __xdr_inline_decode(xdr, nbytes);
if (p == NULL)
return NULL;
memcpy(cpdest, p, nbytes);
return xdr->scratch.iov_base;
}
/**
* xdr_inline_decode - Retrieve XDR data to decode
* @xdr: pointer to xdr_stream struct
* @nbytes: number of bytes of data to decode
*
* Check if the input buffer is long enough to enable us to decode
* 'nbytes' more bytes of data starting at the current position.
* If so return the current pointer, then update the current
* pointer position.
*/
__be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
{
__be32 *p;
if (nbytes == 0)
return xdr->p;
if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
return NULL;
p = __xdr_inline_decode(xdr, nbytes);
if (p != NULL)
return p;
return xdr_copy_to_scratch(xdr, nbytes);
}
EXPORT_SYMBOL_GPL(xdr_inline_decode);
static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
{
struct xdr_buf *buf = xdr->buf;
struct kvec *iov;
unsigned int nwords = XDR_QUADLEN(len);
unsigned int cur = xdr_stream_pos(xdr);
if (xdr->nwords == 0)
return 0;
/* Realign pages to current pointer position */
iov = buf->head;
if (iov->iov_len > cur) {
xdr_shrink_bufhead(buf, iov->iov_len - cur);
xdr->nwords = XDR_QUADLEN(buf->len - cur);
}
if (nwords > xdr->nwords) {
nwords = xdr->nwords;
len = nwords << 2;
}
if (buf->page_len <= len)
len = buf->page_len;
else if (nwords < xdr->nwords) {
/* Truncate page data and move it into the tail */
xdr_shrink_pagelen(buf, buf->page_len - len);
xdr->nwords = XDR_QUADLEN(buf->len - cur);
}
return len;
}
/**
* xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
* @xdr: pointer to xdr_stream struct
* @len: number of bytes of page data
*
* Moves data beyond the current pointer position from the XDR head[] buffer
* into the page list. Any data that lies beyond current position + "len"
* bytes is moved into the XDR tail[].
*
* Returns the number of XDR encoded bytes now contained in the pages
*/
unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
{
struct xdr_buf *buf = xdr->buf;
struct kvec *iov;
unsigned int nwords;
unsigned int end;
unsigned int padding;
len = xdr_align_pages(xdr, len);
if (len == 0)
return 0;
nwords = XDR_QUADLEN(len);
padding = (nwords << 2) - len;
xdr->iov = iov = buf->tail;
/* Compute remaining message length. */
end = ((xdr->nwords - nwords) << 2) + padding;
if (end > iov->iov_len)
end = iov->iov_len;
/*
* Position current pointer at beginning of tail, and
* set remaining message length.
*/
xdr->p = (__be32 *)((char *)iov->iov_base + padding);
xdr->end = (__be32 *)((char *)iov->iov_base + end);
xdr->page_ptr = NULL;
xdr->nwords = XDR_QUADLEN(end - padding);
return len;
}
EXPORT_SYMBOL_GPL(xdr_read_pages);
/**
* xdr_enter_page - decode data from the XDR page
* @xdr: pointer to xdr_stream struct
* @len: number of bytes of page data
*
* Moves data beyond the current pointer position from the XDR head[] buffer
* into the page list. Any data that lies beyond current position + "len"
* bytes is moved into the XDR tail[]. The current pointer is then
* repositioned at the beginning of the first XDR page.
*/
void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
{
len = xdr_align_pages(xdr, len);
/*
* Position current pointer at beginning of tail, and
* set remaining message length.
*/
if (len != 0)
xdr_set_page_base(xdr, 0, len);
}
EXPORT_SYMBOL_GPL(xdr_enter_page);
static struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
void
xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
{
buf->head[0] = *iov;
buf->tail[0] = empty_iov;
buf->page_len = 0;
buf->buflen = buf->len = iov->iov_len;
}
EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
/**
* xdr_buf_subsegment - set subbuf to a portion of buf
* @buf: an xdr buffer
* @subbuf: the result buffer
* @base: beginning of range in bytes
* @len: length of range in bytes
*
* sets @subbuf to an xdr buffer representing the portion of @buf of
* length @len starting at offset @base.
*
* @buf and @subbuf may be pointers to the same struct xdr_buf.
*
* Returns -1 if base of length are out of bounds.
*/
int
xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
unsigned int base, unsigned int len)
{
subbuf->buflen = subbuf->len = len;
if (base < buf->head[0].iov_len) {
subbuf->head[0].iov_base = buf->head[0].iov_base + base;
subbuf->head[0].iov_len = min_t(unsigned int, len,
buf->head[0].iov_len - base);
len -= subbuf->head[0].iov_len;
base = 0;
} else {
base -= buf->head[0].iov_len;
subbuf->head[0].iov_len = 0;
}
if (base < buf->page_len) {
subbuf->page_len = min(buf->page_len - base, len);
base += buf->page_base;
subbuf->page_base = base & ~PAGE_CACHE_MASK;
subbuf->pages = &buf->pages[base >> PAGE_CACHE_SHIFT];
len -= subbuf->page_len;
base = 0;
} else {
base -= buf->page_len;
subbuf->page_len = 0;
}
if (base < buf->tail[0].iov_len) {
subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
subbuf->tail[0].iov_len = min_t(unsigned int, len,
buf->tail[0].iov_len - base);
len -= subbuf->tail[0].iov_len;
base = 0;
} else {
base -= buf->tail[0].iov_len;
subbuf->tail[0].iov_len = 0;
}
if (base || len)
return -1;
return 0;
}
EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
/**
* xdr_buf_trim - lop at most "len" bytes off the end of "buf"
* @buf: buf to be trimmed
* @len: number of bytes to reduce "buf" by
*
* Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
* that it's possible that we'll trim less than that amount if the xdr_buf is
* too small, or if (for instance) it's all in the head and the parser has
* already read too far into it.
*/
void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
{
size_t cur;
unsigned int trim = len;
if (buf->tail[0].iov_len) {
cur = min_t(size_t, buf->tail[0].iov_len, trim);
buf->tail[0].iov_len -= cur;
trim -= cur;
if (!trim)
goto fix_len;
}
if (buf->page_len) {
cur = min_t(unsigned int, buf->page_len, trim);
buf->page_len -= cur;
trim -= cur;
if (!trim)
goto fix_len;
}
if (buf->head[0].iov_len) {
cur = min_t(size_t, buf->head[0].iov_len, trim);
buf->head[0].iov_len -= cur;
trim -= cur;
}
fix_len:
buf->len -= (len - trim);
}
EXPORT_SYMBOL_GPL(xdr_buf_trim);
static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
{
unsigned int this_len;
this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
memcpy(obj, subbuf->head[0].iov_base, this_len);
len -= this_len;
obj += this_len;
this_len = min_t(unsigned int, len, subbuf->page_len);
if (this_len)
_copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
len -= this_len;
obj += this_len;
this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
memcpy(obj, subbuf->tail[0].iov_base, this_len);
}
/* obj is assumed to point to allocated memory of size at least len: */
int read_bytes_from_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
{
struct xdr_buf subbuf;
int status;
status = xdr_buf_subsegment(buf, &subbuf, base, len);
if (status != 0)
return status;
__read_bytes_from_xdr_buf(&subbuf, obj, len);
return 0;
}
EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
static void __write_bytes_to_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
{
unsigned int this_len;
this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
memcpy(subbuf->head[0].iov_base, obj, this_len);
len -= this_len;
obj += this_len;
this_len = min_t(unsigned int, len, 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_t(unsigned int, len, subbuf->tail[0].iov_len);
memcpy(subbuf->tail[0].iov_base, obj, this_len);
}
/* obj is assumed to point to allocated memory of size at least len: */
int write_bytes_to_xdr_buf(struct xdr_buf *buf, unsigned int base, void *obj, unsigned int len)
{
struct xdr_buf subbuf;
int status;
status = xdr_buf_subsegment(buf, &subbuf, base, len);
if (status != 0)
return status;
__write_bytes_to_xdr_buf(&subbuf, obj, len);
return 0;
}
EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
int
xdr_decode_word(struct xdr_buf *buf, unsigned int base, u32 *obj)
{
__be32 raw;
int status;
status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
if (status)
return status;
*obj = be32_to_cpu(raw);
return 0;
}
EXPORT_SYMBOL_GPL(xdr_decode_word);
int
xdr_encode_word(struct xdr_buf *buf, unsigned int base, u32 obj)
{
__be32 raw = cpu_to_be32(obj);
return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
}
EXPORT_SYMBOL_GPL(xdr_encode_word);
/* 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
* set obj to point to it. */
int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
{
struct xdr_buf subbuf;
if (xdr_decode_word(buf, offset, &obj->len))
return -EFAULT;
if (xdr_buf_subsegment(buf, &subbuf, offset + 4, obj->len))
return -EFAULT;
/* Is the obj contained entirely in the head? */
obj->data = subbuf.head[0].iov_base;
if (subbuf.head[0].iov_len == obj->len)
return 0;
/* ..or is the obj contained entirely in the tail? */
obj->data = subbuf.tail[0].iov_base;
if (subbuf.tail[0].iov_len == obj->len)
return 0;
/* use end of tail as storage for obj:
* (We don't copy to the beginning because then we'd have
* to worry about doing a potentially overlapping copy.
* This assumes the object is at most half the length of the
* tail.) */
if (obj->len > buf->buflen - buf->len)
return -ENOMEM;
if (buf->tail[0].iov_len != 0)
obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
else
obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
__read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
return 0;
}
EXPORT_SYMBOL_GPL(xdr_buf_read_netobj);
/* 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 ||
desc->array_len > desc->array_maxlen ||
(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:
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);
}
EXPORT_SYMBOL_GPL(xdr_decode_array2);
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);
}
EXPORT_SYMBOL_GPL(xdr_encode_array2);
int
xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
int (*actor)(struct scatterlist *, void *), void *data)
{
int i, ret = 0;
unsigned int page_len, thislen, page_offset;
struct scatterlist sg[1];
sg_init_table(sg, 1);
if (offset >= buf->head[0].iov_len) {
offset -= buf->head[0].iov_len;
} else {
thislen = buf->head[0].iov_len - offset;
if (thislen > len)
thislen = len;
sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
ret = actor(sg, data);
if (ret)
goto out;
offset = 0;
len -= thislen;
}
if (len == 0)
goto out;
if (offset >= buf->page_len) {
offset -= buf->page_len;
} else {
page_len = buf->page_len - offset;
if (page_len > len)
page_len = len;
len -= page_len;
page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
thislen = PAGE_CACHE_SIZE - page_offset;
do {
if (thislen > page_len)
thislen = page_len;
sg_set_page(sg, buf->pages[i], thislen, page_offset);
ret = actor(sg, data);
if (ret)
goto out;
page_len -= thislen;
i++;
page_offset = 0;
thislen = PAGE_CACHE_SIZE;
} while (page_len != 0);
offset = 0;
}
if (len == 0)
goto out;
if (offset < buf->tail[0].iov_len) {
thislen = buf->tail[0].iov_len - offset;
if (thislen > len)
thislen = len;
sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
ret = actor(sg, data);
len -= thislen;
}
if (len != 0)
ret = -EINVAL;
out:
return ret;
}
EXPORT_SYMBOL_GPL(xdr_process_buf);