Consistently unescape XML attributes when loading scenario

This changes the behaviour of `xp_get_string()` in order to
systematically unescape the returned values, as other XML parsers do.
The custom unescaping in the handling of the `<ereg>` element has been
removed as it is now unneeded.

This will make it possible to e.g. compare strings that contain special
XML characters using `<strcmp>`.

A regression test case has been added to highlight the problem.

SIPp#458

regress/github-#0458/run

@@ -0,0 +1,22 @@
+#!/bin/sh
+# This regression test is a part of SIPp.
+. "`dirname "$0"`/../functions"; init
+
+sippfg -m 1 -sf uas.xml -p 5070 >/dev/null 2>&1 &
+job=$!
+
+sippfg -m 1 -sf uac.xml 127.0.0.1:5070 \
+    -trace_err -error_file err.log \
+    -timeout 4 -timeout_error >/dev/null 2>&1
+status=$?
+wait $job || status=1
+
+if test $status -eq 0; then
+    ok
+else
+    if grep -q 'Matching Error' err.log; then
+        fail "matching error - escaping?"
+    else
+        fail "unknown failure"
+    fi
+fi

regress/github-#0458/uac.xml

@@ -0,0 +1,62 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!DOCTYPE scenario SYSTEM "sipp.dtd">
+<scenario>
+  <send retrans="500" start_txn="invite">
+    <![CDATA[
+
+      INVITE sip:[service]@[remote_ip]:[remote_port] SIP/2.0
+      Via: SIP/2.0/[transport] [local_ip]:[local_port];branch=[branch]
+      From: "Tom Jones" <sip:[email protected]>;tag=[pid]SIPpTag00[call_number]
+      To: "Fromage" <sip:[email protected]>
+      Call-ID: [call_id]
+      CSeq: 1 INVITE
+      Contact: sip:sipp@[local_ip]:[local_port]
+      Content-Length: 0
+
+    ]]>
+  </send>
+
+  <recv response="404" response_txn="invite">
+    <action>
+      <ereg regexp="(&quot;[^&quot;]*&quot; &lt;[^&gt;]*&gt;)" search_in="hdr" header="To:" assign_to="var"/>
+    </action>
+  </recv>
+  <Reference variables="var"/>
+
+  <send ack_txn="invite">
+    <![CDATA[
+
+      ACK [next_url] SIP/2.0
+      Via: SIP/2.0/[transport] [local_ip]:[local_port];branch=[branch]
+      [routes]
+      From: sip:[service]@[local_ip]:[local_port];tag=[pid]SIPpTag00[call_number]
+      To: sip:[service]@[remote_ip]:[remote_port][peer_tag_param]
+      Call-ID: [call_id]
+      CSeq: [cseq] ACK
+      Contact: sip:[service]@[local_ip]:[local_port]
+      Content-Length: 0
+
+    ]]>
+  </send>
+
+  <!--
+    If attribute escaping handling is correct in the scenario loading, then the
+    test below will work. If it doesn't, then it will fail because of the XML
+    entities.
+  -->
+  <nop>
+    <action>
+      <strcmp assign_to="1" variable="var" value="&quot;Fromage&quot; &lt;sip:[email protected]&gt;"/>
+      <test assign_to="result" variable="1" compare="equal" value="0" /> <!-- If strcmp is successful, it returns 0 -->
+    </action>
+  </nop>
+
+  <nop condexec="result" condexec_inverse="true">
+    <action>
+      <warning message="Matching Error: '[$var]' != '&quot;Fromage&quot; &lt;sip:[email protected]&gt;'"/>
+      <exec int_cmd="stop_now" />
+    </action>
+  </nop>
+
+  <timewait milliseconds="500"/>
+</scenario>

regress/github-#0458/uas.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!DOCTYPE scenario SYSTEM "sipp.dtd">
+<scenario>
+  <recv request="INVITE"/>
+
+  <send retrans="500">
+    <![CDATA[
+      SIP/2.0 404 Not Found
+      [last_Via:]
+      [last_From:]
+      [last_To:];tag=[pid]SIPpTag00[call_number]
+      [last_Call-ID:]
+      [last_CSeq:]
+      Contact: sip:sipp@[local_ip]:[local_port]
+      Content-Length: 0
+    ]]>
+  </send>
+
+  <recv request="ACK"/>
+
+  <timewait milliseconds="500"/>
+</scenario>

src/scenario.cpp

@@ -263,12 +263,16 @@ static char* xp_get_keyword_value(const char *name)
 static char* xp_get_string(const char *name, const char *what)
 {
     const char *ptr;
+    char *unescaped;
 
     if (!(ptr = xp_get_value(name))) {
         ERROR("%s is missing the required '%s' parameter.", what, name);
     }
 
-    return strdup(ptr);
+    unescaped = new char[strlen(ptr)+1];
+    xp_unescape(ptr, unescaped);
+
+    return unescaped;
 }
 
 static double xp_get_double(const char *name, const char *what)
@@ -1344,7 +1348,6 @@ void scenario::parseAction(CActions *actions)
 {
     char *        actionElem;
     unsigned int recvScenarioLen = 0;
-    char *        currentRegExp = NULL;
     char **       currentTabVarName = NULL;
     int           currentNbVarNames;
     int           sub_currentNbVarId;
@@ -1357,19 +1360,13 @@ void scenario::parseAction(CActions *actions)
         if(!strcmp(actionElem, "ereg")) {
             ptr = xp_get_string("regexp", "ereg");
 
-            // keeping regexp expression in memory
-            if(currentRegExp != NULL)
-                delete[] currentRegExp;
-            currentRegExp = new char[strlen(ptr)+1];
-            xp_unescape(ptr, currentRegExp);
             tmpAction->setActionType(CAction::E_AT_ASSIGN_FROM_REGEXP);
 
             // warning - although these are detected for both msg and hdr
             // they are only implemented for search_in="hdr"
             tmpAction->setCaseIndep(xp_get_bool("case_indep", "ereg", false));
             tmpAction->setHeadersOnly(xp_get_bool("start_line", "ereg", false));
 
-            free(ptr);
             if ((cptr = xp_get_value("search_in"))) {
                 tmpAction->setOccurrence(1);
 
@@ -1421,7 +1418,7 @@ void scenario::parseAction(CActions *actions)
             int varId = get_var(currentTabVarName[0], "assign_to");
             tmpAction->setVarId(varId);
 
-            tmpAction->setRegExp(currentRegExp);
+            tmpAction->setRegExp(ptr);
             if (currentNbVarNames > 1 ) {
                 sub_currentNbVarId = currentNbVarNames - 1 ;
                 tmpAction->setNbSubVarId(sub_currentNbVarId);
@@ -1433,11 +1430,7 @@ void scenario::parseAction(CActions *actions)
             }
 
             freeStringTable(currentTabVarName, currentNbVarNames);
-
-            if(currentRegExp != NULL) {
-                delete[] currentRegExp;
-            }
-            currentRegExp = NULL;
+            free(ptr);
         } /* end !strcmp(actionElem, "ereg") */ else if(!strcmp(actionElem, "log")) {
             ptr = xp_get_string("message", "log");
             tmpAction->setMessage(ptr);