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/*
This file is part of GNUnet.
(C) 2012,2013 Christian Grothoff (and other contributing authors)
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 3, or (at your
option) any later version.
GNUnet is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNUnet; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
/**
* @author Bartlomiej Polot
* @file regex/regex_block_lib.c
*/
#include "platform.h"
#include "regex_block_lib.h"
/**
* Struct to keep track of the xquery while iterating all the edges in a block.
*/
struct regex_block_xquery_ctx
{
/**
* Xquery: string we are looking for.
*/
const char *xquery;
/**
* Has any edge matched the xquery so far? (GNUNET_OK / GNUNET_NO)
*/
int found;
};
/**
* Iterator over all edges in a block, checking for a presence of a given query.
*
* @param cls Closure, (xquery context).
* @param token Token that follows to next state.
* @param len Lenght of token.
* @param key Hash of next state.
*
* @return GNUNET_YES, to keep iterating
*/
static int
check_edge (void *cls,
const char *token,
size_t len,
const struct GNUNET_HashCode *key)
{
struct regex_block_xquery_ctx *ctx = cls;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " edge %.*s [%u]\n",
(int) len, token, len);
if (strlen (ctx->xquery) < len)
{
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " too long!\n");
return GNUNET_YES;
}
if (0 == strncmp (ctx->xquery, token, len))
{
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " OK!\n");
ctx->found = GNUNET_OK;
}
else
{
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " KO!\n");
}
return GNUNET_YES; /* keep checking for malformed data! */
}
/**
* Check if the regex block is well formed, including all edges
*
* @param block The start of the block.
* @param size The size of the block.
* @param xquery String describing the edge we are looking for.
*
* @return GNUNET_OK in case it's fine.
* GNUNET_NO in case the xquery is not found.
* GNUNET_SYSERR if the block is invalid.
*/
int
GNUNET_REGEX_block_check (const struct RegexBlock *block,
size_t size,
const char *xquery)
{
int res;
struct regex_block_xquery_ctx ctx;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"* Checking block with xquery \"%s\"\n",
xquery);
if ( (GNUNET_YES == ntohl(block->accepting)) && ('\0' == xquery[0]) )
return GNUNET_OK;
ctx.xquery = xquery;
ctx.found = GNUNET_NO;
res = GNUNET_REGEX_block_iterate (block, size, &check_edge, &ctx);
if (GNUNET_SYSERR == res)
return GNUNET_SYSERR;
return ctx.found;
}
/**
* Iterate over all edges of a block of a regex state.
*
* @param block Block to iterate over.
* @param size Size of block.
* @param iterator Function to call on each edge in the block.
* @param iter_cls Closure for the iterator.
*
* @return How many bytes of block have been processed
*/
int
GNUNET_REGEX_block_iterate (const struct RegexBlock *block,
size_t size,
GNUNET_REGEX_EgdeIterator iterator,
void *iter_cls)
{
struct RegexEdge *edge;
unsigned int n;
unsigned int n_token;
unsigned int i;
size_t offset;
char *aux;
offset = sizeof (struct RegexBlock);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"* Start iterating block of size %u, off %u\n",
size, offset);
if (offset > size) // Is it safe to access the regex block?
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"* Block is smaller than struct RegexBlock, END\n");
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
n = ntohl (block->n_proof);
offset += n;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"* Proof length: %u, off %u\n", n, offset);
if (offset > size) // Is it safe to access the regex proof?
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"* Block is smaller than Block + proof, END\n");
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
aux = (char *) &block[1]; // Skip regex block
aux = &aux[n]; // Skip regex proof
n = ntohl (block->n_edges);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "* Edges: %u\n", n);
for (i = 0; i < n; i++) // aux always points at the end of the previous block
{
offset += sizeof (struct RegexEdge);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "* Edge %u, off %u\n", i, offset);
if (offset > size) // Is it safe to access the next edge block?
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"* Size not enough for RegexEdge, END\n");
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
edge = (struct RegexEdge *) aux;
n_token = ntohl (edge->n_token);
offset += n_token;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"* Token lenght %u, off %u\n", n_token, offset);
if (offset > size) // Is it safe to access the edge token?
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"* Size not enough for edge token, END\n");
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
aux = (char *) &edge[1]; // Skip edge block
if (NULL != iterator)
if (GNUNET_NO == iterator (iter_cls, aux, n_token, &edge->key))
return GNUNET_OK;
aux = &aux[n_token]; // Skip edge token
}
// The total size should be exactly the size of (regex + all edges) blocks
// If size == -1, block is from cache and therefore previously checked and
// assumed correct.
if (offset == size || SIZE_MAX == size)
{
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"* Block processed, END OK\n");
return GNUNET_OK;
}
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"* Size %u (%d), read %u END KO\n", size, size, offset);
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
/* end of regex_block_lib.c */
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