MaxScale/server/core/maxscale_pcre2.cc
2019-12-18 13:25:03 +02:00

289 lines
9.4 KiB
C++

/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2023-12-18
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*
*/
/**
* @file maxscale_pcre2.c - Utility functions for regular expression matching
* with the bundled PCRE2 library.
*
* @verbatim
* Revision History
*
* Date Who Description
* 30-10-2015 Markus Makela Initial implementation
* @endverbatim
*/
#include <maxscale/pcre2.h>
#include <maxbase/assert.h>
#include <maxbase/alloc.h>
#include <maxscale/log.hh>
/**
* Utility wrapper for PCRE2 library function call pcre2_substitute.
*
* This function replaces all occurences of a pattern with the provided replacement
* and places the end result into @c dest. This buffer must be allocated by the caller.
* If the size of @c dest is not large enough it will be reallocated to a larger size.
* The size of @c dest is stored in @c size if any reallocation takes place.
*
* @param re Compiled pattern to use
* @param subject Subject string
* @param replace Replacement string
* @param dest Destination buffer
* @param size Size of the destination buffer
* @return MXS_PCRE2_MATCH if replacements were made, MXS_PCRE2_NOMATCH if nothing
* was replaced or MXS_PCRE2_ERROR if memory reallocation failed
*/
mxs_pcre2_result_t mxs_pcre2_substitute(pcre2_code* re,
const char* subject,
const char* replace,
char** dest,
size_t* size)
{
int rc;
mxs_pcre2_result_t rval = MXS_PCRE2_ERROR;
pcre2_match_data* mdata = pcre2_match_data_create_from_pattern(re, NULL);
if (mdata)
{
size_t size_tmp = *size;
while ((rc = pcre2_substitute(re,
(PCRE2_SPTR) subject,
PCRE2_ZERO_TERMINATED,
0,
PCRE2_SUBSTITUTE_GLOBAL,
mdata,
NULL,
(PCRE2_SPTR) replace,
PCRE2_ZERO_TERMINATED,
(PCRE2_UCHAR*) *dest,
&size_tmp)) == PCRE2_ERROR_NOMEMORY)
{
size_tmp = 2 * (*size);
char* tmp = (char*)MXS_REALLOC(*dest, size_tmp);
if (tmp == NULL)
{
break;
}
*dest = tmp;
*size = size_tmp;
}
if (rc > 0)
{
rval = MXS_PCRE2_MATCH;
}
else if (rc == 0)
{
rval = MXS_PCRE2_NOMATCH;
}
pcre2_match_data_free(mdata);
}
return rval;
}
/**
* Do a simple matching of a pattern to a string.
*
* This function compiles the given pattern and checks if the subject string matches
* it.
* @param pattern Pattern used for matching
* @param subject Subject string to match
* @param options PCRE2 compilation options
* @param error The PCRE2 error code is stored here if one is available
* @return MXS_PCRE2_MATCH if @c subject matches @c pattern, MXS_PCRE2_NOMATCH if
* they do not match and MXS_PCRE2_ERROR if an error occurred. If an error occurred
* within the PCRE2 library, @c error will contain the error code. Otherwise it is
* set to 0.
*/
mxs_pcre2_result_t mxs_pcre2_simple_match(const char* pattern,
const char* subject,
int options,
int* error)
{
int err;
size_t erroff;
mxs_pcre2_result_t rval = MXS_PCRE2_ERROR;
pcre2_code* re = pcre2_compile((PCRE2_SPTR) pattern,
PCRE2_ZERO_TERMINATED,
options,
&err,
&erroff,
NULL);
if (re)
{
pcre2_match_data* mdata = pcre2_match_data_create_from_pattern(re, NULL);
if (mdata)
{
int rc = pcre2_match(re,
(PCRE2_SPTR) subject,
PCRE2_ZERO_TERMINATED,
0,
0,
mdata,
NULL);
if (rc == PCRE2_ERROR_NOMATCH)
{
rval = MXS_PCRE2_NOMATCH;
}
else if (rc > 0)
{
/** Since we used the pattern to create the matching data,
* pcre2_match will never return 0 */
rval = MXS_PCRE2_MATCH;
}
pcre2_match_data_free(mdata);
}
else
{
*error = 0;
}
pcre2_code_free(re);
}
else
{
*error = err;
}
return rval;
}
void mxs_pcre2_print_error(int errorcode,
const char* module_name,
const char* filename,
int line_num,
const char* func_name)
{
mxb_assert(filename);
mxb_assert(func_name);
if (mxs_log_is_priority_enabled(LOG_ERR))
{
// 120 should be enough to contain any error message according to pcre2 manual.
const PCRE2_SIZE errbuf_len = 120;
PCRE2_UCHAR errorbuf[errbuf_len];
pcre2_get_error_message(errorcode, errorbuf, errbuf_len);
mxs_log_message(LOG_ERR,
module_name,
filename,
line_num,
func_name,
"PCRE2 Error message: '%s'.",
errorbuf);
}
}
bool mxs_pcre2_check_match_exclude(pcre2_code* re_match,
pcre2_code* re_exclude,
pcre2_match_data* md,
const char* subject,
int length,
const char* calling_module)
{
mxb_assert((!re_match && !re_exclude) || (md && subject));
bool rval = true;
int string_len = ((size_t)length == PCRE2_ZERO_TERMINATED) ? strlen(subject) : length;
if (re_match)
{
int result = pcre2_match(re_match, (PCRE2_SPTR)subject, string_len, 0, 0, md, NULL);
if (result == PCRE2_ERROR_NOMATCH)
{
rval = false; // Didn't match the "match"-regex
if (mxs_log_is_priority_enabled(LOG_INFO))
{
mxs_log_message(LOG_INFO,
calling_module,
__FILE__,
__LINE__,
__func__,
"Subject does not match the 'match' pattern: %.*s",
string_len,
subject);
}
}
else if (result < 0)
{
rval = false;
/* The __FILE__ etc macros here do not match calling_module, but
* the values are only used for throttling messages. */
mxs_pcre2_print_error(result, calling_module, __FILE__, __LINE__, __func__);
}
}
if (rval && re_exclude)
{
int result = pcre2_match(re_exclude, (PCRE2_SPTR)subject, string_len, 0, 0, md, NULL);
if (result >= 0)
{
rval = false; // Matched the "exclude"-regex
if (mxs_log_is_priority_enabled(LOG_INFO))
{
mxs_log_message(LOG_INFO,
calling_module,
__FILE__,
__LINE__,
__func__,
"Query matches the 'exclude' pattern: %.*s",
string_len,
subject);
}
}
else if (result != PCRE2_ERROR_NOMATCH)
{
rval = false;
mxs_pcre2_print_error(result, calling_module, __FILE__, __LINE__, __func__);
}
}
return rval;
}
namespace maxscale
{
std::string pcre2_substitute(pcre2_code* re,
const std::string& subject,
const std::string& replace,
std::string* error)
{
mxb_assert(re);
std::string rval = subject;
size_t size_tmp = rval.size();
int rc;
while ((rc = pcre2_substitute(re, (PCRE2_SPTR) subject.c_str(), subject.length(),
0, PCRE2_SUBSTITUTE_GLOBAL, NULL, NULL,
(PCRE2_SPTR) replace.c_str(), replace.length(),
(PCRE2_UCHAR*) &rval[0], &size_tmp)) == PCRE2_ERROR_NOMEMORY)
{
rval.resize(rval.size() * 2 + 1);
size_tmp = rval.size();
}
if (rc < 0)
{
if (error)
{
char errbuf[1024];
pcre2_get_error_message(rc, (PCRE2_UCHAR*)errbuf, sizeof(errbuf));
*error = errbuf;
}
rval.clear();
}
else
{
rval.resize(size_tmp);
}
return rval;
}
}