diff options
Diffstat (limited to 'kernel/net/sunrpc/xdr.c')
| -rw-r--r-- | kernel/net/sunrpc/xdr.c | 1515 |
1 files changed, 1515 insertions, 0 deletions
diff --git a/kernel/net/sunrpc/xdr.c b/kernel/net/sunrpc/xdr.c new file mode 100644 index 000000000..4439ac4c1 --- /dev/null +++ b/kernel/net/sunrpc/xdr.c @@ -0,0 +1,1515 @@ +/* + * 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); + |