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regex: Enhance pcre_match to optionally return the matched string #3901

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regex: Enhance pcre_match to optionally return the matched string #3901

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11 changes: 9 additions & 2 deletions modules/regex/doc/regex_admin.xml
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Original file line number Diff line number Diff line change
Expand Up @@ -222,13 +222,14 @@ modparam("regex", "pcre_extended", 1)

<section id="func_pcre_match" xreflabel="pcre_match()">
<title>
<function moreinfo="none">pcre_match (string, pcre_regex)</function>
<function moreinfo="none">pcre_match (string, pcre_regex [, match])</function>
</title>

<para>
Matches the given string parameter against the regular expression pcre_regex,
which is compiled into a PCRE object. Returns TRUE if it matches, FALSE
otherwise.
otherwise. When the optional match parameter is provided, it is set to
the matched part of the string, or cleared if there is no match.
</para>

<para>Meaning of the parameters is as follows:</para>
Expand All @@ -245,6 +246,12 @@ modparam("regex", "pcre_extended", 1)
in a PCRE object.
</para>
</listitem>
<listitem>
<para>
<emphasis>match</emphasis> (var, optional) - Writable pseudo-variable
where the matched part of the string is stored.
</para>
</listitem>
</itemizedlist>

<para>
Expand Down
104 changes: 94 additions & 10 deletions modules/regex/regex_mod.c
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Original file line number Diff line number Diff line change
Expand Up @@ -77,6 +77,8 @@
#include "../../str.h"
#include "../../locking.h"
#include "../../mod_fix.h"
#include "../../pvar.h"
#include "../../error.h"
#include "../../mi/mi.h"

#define START 0
Expand Down Expand Up @@ -128,12 +130,15 @@ static void destroy(void);
*/
static int load_pcres(int);
static void free_shared_memory(void);
static int fixup_check_pv_setf(void **param);
static int set_match_pvar(struct sip_msg *msg, pv_spec_t *match, str *value);


/*
* Script functions
*/
static int w_pcre_match(struct sip_msg* _msg, str* string, str* _regex_s);
static int w_pcre_match(struct sip_msg* _msg, str* string, str* _regex_s,
pv_spec_t *match);
static int w_pcre_match_group(struct sip_msg* _msg, str* string, int* _num_pcre);


Expand All @@ -152,7 +157,8 @@ static const cmd_export_t cmds[] =
{
{"pcre_match", (cmd_function)w_pcre_match, {
{CMD_PARAM_STR,0,0},
{CMD_PARAM_STR,0,0}, {0,0,0}},
{CMD_PARAM_STR,0,0},
{CMD_PARAM_VAR|CMD_PARAM_OPT, fixup_check_pv_setf, 0}, {0,0,0}},
REQUEST_ROUTE|FAILURE_ROUTE|ONREPLY_ROUTE|BRANCH_ROUTE|LOCAL_ROUTE|
STARTUP_ROUTE|TIMER_ROUTE|EVENT_ROUTE},
{"pcre_match_group", (cmd_function)w_pcre_match_group, {
Expand Down Expand Up @@ -584,8 +590,49 @@ static void free_shared_memory(void)
* Script functions
*/

static int fixup_check_pv_setf(void **param)
{
if (!pv_is_w(((pv_spec_t*)*param))) {
LM_ERR("invalid output parameter: must be writable\n");
return E_SCRIPT;
}

return 0;
}


static int set_match_pvar(struct sip_msg *msg, pv_spec_t *match, str *value)
{
pv_value_t pv_val;

if (!match)
return 0;

if (!value) {
if (pv_set_value(msg, match, 0, NULL) != 0) {
LM_ERR("failed to clear match pvar\n");
return -1;
}

return 0;
}

memset(&pv_val, 0, sizeof(pv_val));
pv_val.flags = PV_VAL_STR;
pv_val.rs = *value;

if (pv_set_value(msg, match, 0, &pv_val) != 0) {
LM_ERR("failed to set match pvar\n");
return -1;
}

return 0;
}


/*! \brief Return true if the argument matches the regular expression parameter */
static int w_pcre_match(struct sip_msg* _msg, str* string, str* _regex_s)
static int w_pcre_match(struct sip_msg* _msg, str* string, str* _regex_s,
pv_spec_t *match)
{
pcre2_code *pcre_re = NULL;
int pcre_rc;
Expand All @@ -594,8 +641,12 @@ static int w_pcre_match(struct sip_msg* _msg, str* string, str* _regex_s)
PCRE2_SIZE pcre_erroffset;
#ifdef PCRE2_LIB
pcre2_match_data *match_data;
PCRE2_SIZE *ovector;
#else
int ovector[3];
#endif
str regex;
str match_str;

if (pkg_nt_str_dup(&regex, _regex_s) < 0)
return -1;
Expand All @@ -616,10 +667,19 @@ static int w_pcre_match(struct sip_msg* _msg, str* string, str* _regex_s)
string->len, /* the length of the subject */
0, /* start at offset 0 in the subject */
0, /* default options */
NULL, /* output vector for substring information */
0); /* number of elements in the output vector */
match ? ovector : NULL, /* output vector for substring information */
match ? 3 : 0); /* number of elements in the output vector */
#else
match_data = pcre2_match_data_create(0, NULL); // no captures needed
if (match)
match_data = pcre2_match_data_create_from_pattern(pcre_re, NULL);
else
match_data = pcre2_match_data_create(0, NULL);
if (!match_data) {
LM_ERR("failed to allocate match data\n");
pcre2_code_free(pcre_re);
pkg_free(regex.s);
return -1;
}

pcre_rc = pcre2_match(
pcre_re, /* the compiled pattern */
Expand All @@ -629,8 +689,6 @@ static int w_pcre_match(struct sip_msg* _msg, str* string, str* _regex_s)
0, /* default options */
match_data, /* match data block */
NULL); /* match context */

pcre2_match_data_free(match_data);
#endif

/* Matching failed: handle error cases */
Expand All @@ -643,14 +701,40 @@ static int w_pcre_match(struct sip_msg* _msg, str* string, str* _regex_s)
LM_DBG("matching error '%d'\n", pcre_rc);
break;
}
#ifdef PCRE2_LIB
pcre2_match_data_free(match_data);
#endif
pcre2_code_free(pcre_re);
pkg_free(regex.s);
if (set_match_pvar(_msg, match, NULL) < 0)
return -1;
return -1;
}

LM_DBG("'%s' matches '%s'\n", string->s, regex.s);

if (match) {
#ifdef PCRE2_LIB
ovector = pcre2_get_ovector_pointer(match_data);
#endif
match_str.s = string->s + ovector[0];
match_str.len = (int)(ovector[1] - ovector[0]);

if (set_match_pvar(_msg, match, &match_str) < 0) {
#ifdef PCRE2_LIB
pcre2_match_data_free(match_data);
#endif
pcre2_code_free(pcre_re);
pkg_free(regex.s);
return -1;
}
}

#ifdef PCRE2_LIB
pcre2_match_data_free(match_data);
#endif
pcre2_code_free(pcre_re);
pkg_free(regex.s);
LM_DBG("'%s' matches '%s'\n", string->s, regex.s);
return 1;
}

Expand Down Expand Up @@ -769,7 +853,7 @@ mi_response_t *mi_pcres_match(const mi_params_t *params, struct mi_handler *asyn
}

/* handle call back function result */
rc = w_pcre_match(NULL, &string, &pcre_regex);
rc = w_pcre_match(NULL, &string, &pcre_regex, NULL);
LM_DBG("w_pcre_match: string<%s>, pcre_regex=<%s>, result:<%i>\n", string.s, pcre_regex.s, rc);

switch(rc) {
Expand Down
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